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Misc May Creek Drainage Improvement
VICINTIY MAP ---.. , COALf1ELD INDEX .s&.EL DESCRIPTION 1. VICINITY ~AP AND INDEX PROJECT "LOCATION 2. L£GE~DS AND ABBREVIATIONS 3. SUMMARY.&.NO OUANllllES (droft version) "4. EXlSTlNG CONOITIOJ6, SHEET KEY. LEGEND, CONSTRUCTION NOTES 5. TEMPORARY EROSION N-ID S£O\L4ENT CONTROL PLAN AND LEGEND 6. TEMPORARY (ROSION AND SEOIMENT CONTROL Pl.AN 7. lESe SEDIMENT DISPOSAL AND PUMPING LOCATIONS (draft ~fsion) 8. TEMPORARY EROSION AND SEOIMENT CONTROL NOTES AND DETAiLS 9. TEI.1PORARY EROSION AND SEDIMENT DETAILS 10. PLAN AND PROFILE 51A. 0+00 TO STA 8+00 11. PLAN AND PROFILE, STA. 8+00 TO STA. 16+20 12. PLAN AND PROnLE. Sf ..... 16+20 TO STA. 24+00 13. PLAN AND PROFILE. STA. 2:4+00 TO STA 29+00 END OF PROJECT 14. WETLAND AND RIPARIAN MI11(;.A,TlON PlAN 15. CROSS SECT10NS AND HABITAT Mm(JATION DETAILS , 6. CROSS SECTIONS AND HABITAT MmGATlON DETAILS 17. FlSH HABITAT ENHANCEMENT INSTALlATION DETAILS AND NOTES 18. PLANTING PlAN I --...o.GT Dt"JOl caN 171201 \ I;;:;' - ~ King County Department of Natural Resources and Parks Water and Land Resources DMsion Stormwater Services SectIon Capital Services Unit ChrtsUe TN8, DInIdDr Depaf1ment of Natural R8MNroIIII and ParIaI ~~ \ ~~,. _dJ ",-;'" MAY CREEK DRAINAGE IMPROVEMENT SE May Valley Rd. + 148th Ave SE C'" hy Of P", .. _ '. r-, • --"Un j...J1Cinn;··,c. {' _ . . "f I...:. JiL.'ISiOI/ AU6 -" [ui! 1R~'(j::)k ~ King County _rt ___ _ t.CAYCREEK~~1 "'-==--'0_ .. -"",~---------~ VICNTY MAl" AN) NleX ~ :::I: toot 0:1 ~ N ~m 1 '" 18 ."," -. • ':i! \~ ,~ 'o! 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II )h---J------J-,;-;;"-,'.,-,.'~ , , ---------------------------------- EXHIBIT 7 \ -------------------- EXHIBIT 8 ( . .:' .... ti King County Water and Land Resources Division Department of Natural Resources and Parks King Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 206-296-6519 Fax 206-296-0192 TTY Relay: 711 EXHIBIT 9 Mitigated Determination of Non-Significance Date of Issue: September 8, 2010 Name of Proposal: May Creek Drainage Improverrient Project (9A 1205) Description of Proposal: King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. Sediment accumulation and in-stream vegetation (e.g., reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used pastures on adjacent rural residential properties with flood conditions now persisting well into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both the start and end of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration oflocalized ·flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. Due to the high groundwater table in the May Valley and because there will be no measureable difference in the geographic extent of flooding, it is not likely that this project will change the amount of wet pasture or wetland in the project vicinity. In addition, the project hydraulic analysis found that the potential for erosion downstream of May Valley is virtually unchanged for the pre-versus post-project conditions. Flow obstructing in-stream vegetation and accumulated sediment will be removed from the stream channel primarily using machinery operated from the stream bank. The vegetation and sediment removal will negatively impact existing in-stream fish habitat. Mitigation has been proposed to offset these impacts. Mitigation: The following mitigation will be implemented to avoid, minimize, and compensate for negative impacts to the in-stream and wetland habitat. • During construction, the stream flow will be diverted around the work area, and in-water work will only be conducted during the summer low flow when fish are less likely to be present. A King County biologist will be onsite during construction to monitor water quality. • Construction techniques, such as utilizing existing access roads or using temporary steel plates (or equivalent), where additional acces.s is needed, will minimize disturbance to existing vegetation. In addition, direct access to the stream channel by equipment will only be allowed in specific areas where vegetation disturbance can be minimized. • Approximately 1.3 acres of wetland and riparian vegetation will be planted along May Creek (IS feet on each side of the stream from I 48th A venue SE upstream to the end of the project). Fencing will be installed to protect the plantings and the stream from livestock. 813112010 -, Mitigated Determination of Non-Significance May Creek Drainage Improvement Project Page 2 • Approximately 3.75 acres of wetland will be enhanced on the west side of 148th Avenue SE by removing invasive reed canarygrass and replanting with native wetland vegetation. Off- channel alcoves will also be excavated along May Creek in this location and large woody debris and streambed gravel will be added in the alcoves to enhance wetland fish habitat. • Fish habitat and natural stream processes witl be restored at either the confluence of Long Marsh Creek and May Creek, or at another similar location in the project vicinity. Location of Proposal: The project is located in the May Valley near the cities of Renton and Newcastle (Sections 2 and 3, Township 23N, Range 5E) on the south side ofSE May Valley Road. The project area includes multiple segments of May Creek between approximately River Mile 4.3 (about 0.25 miles downstream of 148th Avenue SE in Renton) and River Mile 4.9. Responsible Official: Position/Titie: Address: DATE: q-vlO Proponent and Lead Agency: Contact Person(s): Mark Isaacson Division Director, Water and Land Resources Division 201 South Jackson Street, Suite 600 SIGNATURE: /fo6P Seattle, WA 981lp4-55 II • King County Department of Natural Resources and Parks Water and Land Resources Division Doug Chin, Project Manager, 206-296-8315 The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An Environmental Impact Statement (EIS) is not required under Revised Code of Washington (RCW) 43.2 IC.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. THIS INFORMATION IS AVAILABLE TO THE PUBLIC ON REQUEST (for a nominal photocopying fee). It is also available on the King County website at: http://IYwIV.kingcollnty.gov/environmenlllVatersheds/cedar -Li ver -I ake-walma y -creek. aspx THIS MITIGATED DETERMINATION OF NON-SIGNIFICANCE (MONS) is issued under Washington Administrative Code (WAC) 197-11-340(2). The lead agency will not act on this proposal until after September 22, 2010. Comments must be submitted or postmarked by that date. For additional information, please contact: Doug Chin, Project Manager King County Water and Land ResourcesDivision 201 South Jackson Street, Suite 600 Seattle, W A 98104-3855 (206) 296-83 15 Doug.Chin@kingcounty.gov 8/) t/:!OIO I I I I I I I I I I I I I I I I I I I EXHIBIT 11) ----------- City of Renton Planning Division AUG -5 "lull May Creek Drainage Improvement Project (9A1205) King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan Prepared by: King County Road Services Division Lindsey Miller, Environmental Engineer Erick Thompson, Senior Environmental Engineer King County Water and Land Resources Division Doug Chin, Supervising Engineer Prepared for: King County Department of Natural Resources and Parks Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 Revised July 2011 -, • • • • • • • • • -. • • I • I I I • I ._------------------------------------------- Table of Contents . Executive Summary .......................................................................................................... iii 1. Introduction ................................................................................................................ 1 2. Project Description ............................................................................... , ..................... 2 3. Existing Conditions .................................................................................................... 6 3.1. . Geology .............•........................•................................•....•....•..•.........................•........•.. 6 3.2. Stream Habitat Conditions .......................................................................................... 6 3.3. Wetlands Conditions .•.•............................•.......................................•..•....•................... 9 3.4. Hydraulic Conditions ................................................................................................... 9 4. Impact Analysis ........................................................................................................ 13 4.1. Stream Impacts ...•..•.......................•..•......•............•....•..•............................•................ 13 4.2. Wetland Impacts .................•....•.........•........................................................................ 16 5. Mitigation Approach ................................................................................................ 19 5.1. Impact Avoidance and Minimization ....................................................................... 19 5.2. Compensatory Mitigation ............ ; ............................................................................. 20 5.3. Compensatory Mitigation Goals ............................................................................... 24 5.4. Compensatory Mitigation Objectives ....................................................................... 24 5.5. Compensatory Mitigation Description / Design ....................................................... 25 6. Performance Standards, Monitoring, Maintenance, and Contingencies ............ 27 6.1. Performance Standards ............................................................................................. 27 6.2. Monitoring ....•.....................• ; ...•.•....•......................•..•............................•.•.................. 27 6.3. Maintenance ........................................................................... " .......•.............•.•........... 28 6.4. Protection .................................................................................................................... 28 6.5. Contingencies .............................................................................................................. 28 7. References ................................................................................................................ 29 Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan July 2011 List of Tables Table I: Type and Location of Vegetation RemovaL ..................................................... 14 Table 2: Summary of Stream and Wetland Impacts ......................................................... 17 Table 3: Mitigation Ratios and Proposed Mitigation Areas ............................................. 22 List of Figures Figure I: Project Vicinity Map ........................................................................................ : .. 5 Figure 2: Habitat Unit Proportions ..................................................................................... 8 Figure 3: Existing Riparian and In-Stream Vegetation .................................................... 11 Figure 4: Existing In-stream and Wetland Habitat ........................................................... 12 Appendices Appendix A -May Creek Drainage Improvement Design Plans Appendix B -Long Marsh Creek Restoration Design Plans Impact Analysis and Mitigation Plan ii May Creek Drainage Improvement Project July 201 I I I I I I I I I' I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Executive Summary King County Water and Land Resources Division (WLRD) is proposing to improve flow conditions along May Creek between River Mile (RM) 4.3 and 4,9 in the May Valley located in southeastern King County near the cities of Renton and Newcastle. One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990) and three tributaries to May Creek are within the proposed project area. May Creek in this area is nearly flat and flows through large wetlands, many of which are currently used as pastures for horses. Historically, May Valley provided floodwater storage for tributaries draining the upper May Creek basin. May Creek was then ditched into a uniform channel in order to use the floodplain for agricultural purpose. Limited capacity to transport sediment through the flat valley allowed sediment to accumulate. Landowners periodically cleared the stream of sediment and in-channel plants until about the I 940s (King County 1995). Since then, development in the upper watershed to the north and south of May Valley has increased stormwater run-off, leading to an increase in the frequency and duration, but not magnitude, of flooding in May Valley (King County 1995). In addition, invasive non-, native vegetation has choked the channel exacerbating the duration of flooding. The flat May Valley reach of May Creek stores stormwater and sediment, releasing both to a higher gradient ravine downstream of the study reach. Slow water and cover from overhanging vegetation in the study reach provide rearing and refuge habitat for fish. To improve flow conditions in May Creek, King County WLRD is proposing to remove accumulated sediment and channel-blocking vegetation in May Creek, as well as reconstruct a portion of Long Marsh Creek to provide sediment storage. As a result of the proposed vegetation and sediment removal, aquatic and wildlife species may be temporarily or permanently degraded in May Creek. Vegetation removal in these areas· would degrade riparian habitat by reducing canopy cover, organic inputs, prey sources, bank stability, and future large wood recruitment. May Creek would experience localized hydraulic changes within the project area when the willow, reed canarygrass and sediment removal occurs. Riparian and in-stream habitat associated with Long Marsh Creek would also be temporarily degraded as a result of the channel reconstruction. King County has designed the project to avoid and minimize impacts to wetlands, streams, and buffers to the greatest extent possible. Impacts that cannot be avoided and minimized must be compensated for by constructing mitigation. The mitigation goal for this project is to achieve no overall net loss in habitat functions in the May Creek sub- basin. This would be accomplished with out-of-kind mitigation by enhancing approximately five acres of riparian buffer and riverine wetland. The enhancements would include planting native riparian/wetland vegetation, reed canary grass suppression, Impact Analysis and Mitigation Plan iii July 2011 May Creek Drainage Improvement Project construction of two off-channel alcoves, placement of large woody debris (76 pieces), and installation of snags in the wetland. The mitigation is considered out-of-kind, because the majority of the impacts are to in-stream habitat, while the proposed mitigation enhances riparian and wetland habitat. Impact Analysis and Mitigation Plan iv July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1. Introduction King County Water and Land Resources Division (WLRD) proposes to improve in- stream flow of May Creek in May Valley between about RM 4.3 and 4.9 in southeastern King County, near the cities of Renton and Newcastle (Figure I) Sections 2 and 3, Township 23N, Range SE. Sediment accumulation and in-stream vegetation (e.g., reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used horse pastures on adjacent rural residential properties, with standing water and wet pastures now persisting into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both the start and end of the wet season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. The reach proposed for improvement begins on the south side of SE May Valley Road about 0.1 mile downstream of 148th Avenue SE in Renton and includes the main stem of May Creek extending upstream about 2,900 feet to a point just downstream from the confluence of May Creek with Indian Meadow Creek. One large riverine wetland, May Creek #S, May Creek, and three tributaries to May Creek are within the proposed project area. The project area is located in the Watershed Resource Inventory Area (WRIA) 8 Lake Washington Basin. The existing conditions of streams and wetlands are described in more detail in Section 3. The King County current zoning classification in the majority ofthe project area is RA-S and RA-IO, rural residential with future development limited to rural uses with maximum densities of one house per five acres and ten acres, respectively. There is also a designated open space tract on the west side of l48th Avenue SE within the City of Renton where the majority of the compensatory mitigation would be constructed .. Currently, small horse farms and open space are the primary land uses.in the project area. A large portion of the riverine wetland in May Valley was converted to agriculture in the early 1900s, and May Creek was regularly dredged to support agriculture. About SO years ago, regular dredging ceased in May Creek, and agricultural production has ceased as a result of increased flooding. The small farms in the project area are flooded during most months of the year. Many of these pastures are located within the delineated wetland boundary. Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan July 2011 The purpose of this report is to analyze the potential stream and wetland impacts associated with the project, and to describe how the mitigation has been designed to avoid, minimize, and compensate for these impacts. 2. Project Description The project proposal consists offour components: vegetation removal, sediment removal, sediment management, and stream/wetland mitigation. The vegetation/sediment removal and the sediment management would negatively impact existing in-stream fish habitat and riparian buffer functions, so mitigation has been proposed to offset these impacts. The project components are described below. Vegetation Removal: The first component of the project includes removal of flow obstructing in-stream vegetation and debris that have been identified as choking the channel and creating a backwater effect, causing flooding on adjacent properties during small storm events. Invasive reed canarygrass is the dominant vegetation that would be removed from the channel and banks. In addition, willows, located in multiple locations throughout the project area, currently have branches crossing over the stream channel at selected locations within the winter flow elevation, further contributing to the backwater effect. A portion of the willows that are identified as obstructing flow would also be removed. The willows on the west side of 148th Avenue SE would be primarily removed by hand, but some small, hand-held, mechanized machinery may be used to assist. Willows and reed canarygrass on the east side of 148th Avenue SE would be removed in conjunction with the sediment removal using machinery, most likely a low impact spyder hoe, operated from the stream bank. Prior to removal of in-stream vegetation using machinery, the stream would be diverted around the construction site and erosion and sediment control best management practices would be used during construction to minimize temporary downstream water-quality impacts (King County July 2011). The impacts associated with the vegetation removal are described in Section 4. Sediment Removal: Sediment would be removed from the stream channel using machinery, most likely a low impact spyder hoe, operated from the stream bank. The stream would be diverted around the construction site and erosion and sediment control best management practices would be used during construction to minimize temporary downstream water-quality impacts (King County July 20 II). Construction techniques, such as, using existing access roads and requiring all machinery to be tracked or rubber tired, would be used to minimize temporary impacts to adjacent wetlands. Sediment would be first placed in on-site soil drying areas and then would be disposed of on-site in a stable, non-erosive manner outside flood prone and sensitive areas. The impacts associated with the sediment removal are described in Section 4. Sediment Management: To increase the longevity of the project, 300 feet of the Long Marsh Creek channel and its confluence with May Creek would be reconstructed to allow Impact Analysis and Mitigation Plan 2 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I sediment to drop out more naturally prior to reaching the mainstem of May Creek. This reconstruction would include an approximately 100 foot long side channel adjacent to May Creek. Based on the sediment yield rate in Long Marsh Creek over the past eight years (2002 to 2010), the channel reconstruction wbuld provide approximately 70 years of sediment storage capacity. StreamlWetland Mitigation: The final component of the project includes providing mitigation to avoid, minimize, and compensate for in-stream and wetland habitat impacts. The following mitigation would be implemented and is further described in Section 5: • During construction, the stream flow would be diverted around the work area, and in- water work would only be conducted during summer low flow when fish are less likely to be present. King County staff would be onsite during construction to monitor water quality. Water quality monitoring and protection procedures are described in the project's Construction Water Quality Protection and Monitoring Plan (King County July 20 II). • Construction techniques, such as using existing access roads and requiring all machinery to be tracked or rubber tired would minimize disturbance to existing vegetation. In addition, direct access to the stream channel by equipment would be in specific areas where vegetation disturbance can be minimized and removal of mature trees can be avoided. Excavation would likely be performed by spyder hoe, which is excavator designed for rough terrain and low impact operation in sensitive areas. Stream access points would be limited to avoid removal of mature trees. • Prior to sediment removal, approximately 60 linear feet of streambed gravels located in May Creek (Station 15+60 to 16+30) near the confluence of Long Marsh Creek, would be removed and saved so that they can be placed back in the same reach of stream channel after the sediment removal is complete. • A buffer of native vegetation (primarily wetland vegetation) would be restored for approximately 15 feet on each side of May Creek east and west of 148th Avenue SE for a total of approximately two acres. This buffer is intended to minimize reed canarygrass infestation and to compensate for the cover that would be lost by removing flow-obstructing willows and reed canarygrass. Native vegetation would be planted in areas where, under existing conditions, only reed canarygrass exists. In most of the project area, the regulatory stream buffer is contained within the delineated wetland boundary, which means that stream buffer enhancement could also be considered wetland enhancement. Fencing would be installed around the planting areas to eliminate livestock access to the newly planted areas and to the stream. Impact Analysis and Mitigation Plan .3 July 2011 May Creek Drainage Improvement Project • In addition to the two acres of riparian buffer planting, an additional three acres of wetland enhancement would be constructed on the west side of l48th Avenue SE to compensate for impacts associated with the sediment removal. This enhancement would include construction of approximately 0.24 acres of off-channel wetland alcoves along May Creek, reed canarygrass suppression, placement of large woody debris (LWD) (76 pieces), two snags, and planting native vegetation. This would provide out-of-kind mitigation for impacts to in-stream habitat functions by enhancing wetland habitat functions. • King County would protect the mitigation areas in perpetuity by recording a conservation easement, or similar document, on the title of each property. Impact Analysis and Mitigation Plan 4 May Creek Drainage Improvement Project July 2011 " I I I I I I I I I I I I I I I I I I I May Creek Drainage Improvement Project Project Vicinity • Study Area 0 Mile Markers /'/ Stream Incorporated Areas • Cougar Mountain Wildland Park March 2010 tQ King County 380 570 T1w ............ -.-0II'I1fIiI_ ... 1IMn-..w~ ~ CowMy .......• __..01 __ II Nljldto -.. ....... IIGIIoI. IOni Catnr ..... 110.. .....01'-.-. __ Of iInpIId ... "'~ ___ .....--01' rigta ID ....... _~ TJooII;_II .. ~Iar ...... ..-..yPf'Cldod. .. Cao.ftyllMllnCllt.. ...... blftY~.~ 1nd ..... ~0! ______ ....... ~~ rot-..:.1ID. __ 0I'Ia.tpf'lllll ........ -..... .. ... ar_oI .. l ........... canllliNdon .. _. My .... 01 !hi. _ or I,*",,-on .... ""'II .. PfO/'IIIlhd -.xl¥ '""'*' ............. at Mq Counl)'. Figure 1 I I I I I I I I I I I I I I I I 3. Existing Conditions This section describes the existing geology, stream, wetland and hydrologic conditions in the project area. 3.1. Geology The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice- melt runoff and is part of the "Kennydale Channel". The recessional phase of the Vashon Glaciation created a series of drainage channels. As the Vashon Glacier receded, the outlet drainage continued to shift to the northwest through the Cedar Grove, Kennydale; and Eastgate Channels (now occupied by 1-90). The valley is underlain by recent alluvium and wetland deposits over recessional outwash deposits and compacted glacial till. These recent deposits overlie Eocene Tukwila Formation. The Tukwila Formation is composed of volcanic tuff, fine-grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop east of 146 th Avenue Southeast and forms a physical boundary between the downstream ravine and May Valley upstream. The compacted glacial materials and bedrock are resistant to erosion by May Creek in the valley. Surface water infiltration into the glacial till and bedrock is limited due to low permeability. 3.2. Stream Habitat Conditions May Creek is about 11.3 kilometers (seven miles) long, with about 30.6 km (19 miles) of tributary streams, draining about 38.3 square kilometers (14 square miles). It is classified as a Type F Water (fish present) under the King County Critical Area Code, requiring a 50.3 m (I 65-ft) regulatory buffer. Under City of Renton Critical Area Code, May Creek is considered a Class 2 stream (salmonid bearing) requiring a I OO-foot buffer. Three tributary creeks (Indian Meadow Creek, Long Marsh Creek, and Greenes Creek) join the mainstem of May Creek in the project area, which flows through the valley and into a: narrow, erosive canyon before flowing into Lake Washington. May Valley was historically an area of sediment deposition and flood storage, and the stream channel braided through extensive wetlands. The stream was put in a ditched single-strand channel so the surrounding floodplain could be used for agriculture and was regularly dredged until about 50 years ago. The May Valley provides stormwater storage, which helps control erosion downstream of the project area (King County 2001, Anchor QEA 2010). Riparian areas adjacent to May Creek are mostly wetland that has been converted to agriculture (wetlands are described in Section 3.3). These riparian areas are primarily dominated by reed canarygrass; however, the stream in the western reach of the project is beginning to revert to more natural conditions due to the presence of an undisturbed buffer of willows (Salix spp.) and red alder (Alnus rubra) about 50 to 75 feet wide. These woody plants stabilize stream banks, provide shade, food, and hiding cover, and increase in-stream Impact Analysis and Mitigation Plan 6 July 2011 May Creek Drainage Improvement Project habitat complexity by providing hard points that create a mixture of slow-water and fast- water areas. The channel in the upstream portion of the project reach lacks woody plants and is almost exclusively vegetated with reed canarygrass. The channel in this reach is more uniform and has filled in with sediment so it is more prone to flooding. Figure 3 shows the vegetation units in the project area. In-stream habitat in the surveyed reach of May Creek is influenced by riparian plant communities. Aquatic habitat is more complex in places where the riparian corridor has woody plants, such as willows, engaged with the stream channel and connected floodplain. Overhanging or rooted willow branches or stems provide cover and hard points necessary for bedform complexity, producing both turbulent and non-turbulent flow areas, and creating six of the nine pools identified in the project area (King County 20 lOb). Terrestrial insects falling from the willow canopy provide food for fish living in the stream, and fallen leaves provide nutrients. Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel. May Creek within the surveyed stream reach was dominated by slow-water glides (Figure 2). Pools made up approximately 25 percent of the surface area in Reaches One and Two, approximately ten percent of the area in Reach Three, and approximately 13 percent of the area over the entire surveyed reach; no pools were present in Reach Four. All of the pools were lateral scour pools except one mid-channel pool in Reach One. Fast water was limited to a single low-gradient riffle at the 148th Avenue SE Bridge, and a couple of pool tail-outs in Reach One. Impact Analysis and Mitigation Plan 7 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 100 80 60 40 20 o IJ4 [8 co 85 Reach 1 Reach 2 Reach 3 Reach 4 Entire o Glide • Pool [] Riffle Figure 2: Habitat Unit Proportions, as surface area (m 2). Dotted area is fast water; solid area is slow water. Water flows from Reach 4 to Reach I. Many of the areas inventoried as glide during.the low-flow stream survey in August 2010 had both turbulent and non-turbulent flow during the February 2010 stream reconnaissance. This is most apparent in Reach Two, which has a relatively wide, mature, willow-dominated riparian corridor. Dense willow branches cross the stream channel throughout this reach, functioning like a debris complex and creating numerous backwater areas during higher flows. This reach is well-connected with its floodplain, and some floodplain terracing is present, which also increases habitat complexity during higher flows. The wider forested riparian area has shaded out reed canarygrass. In areas where reed canarygrass dominates, such as Reach Four, the channel tends to be deeper and has much thicker accumulations of fine sediment. May Creek historically was an important salmon stream in the Lake Washington Basin '(WDF 1975). The stream supported five species of salmonids: Chinook (Oncorhyncus Tschawytscha), sockeye (0. nerka), and coho (0. kisutch) salmon, and rainbow/steelhead (0. mykiss) and cutthroat (0. clarki) trout (King County 1995). Salmon still use the stream and its tributaries even though their numbers have decreased (King County 1995). Chinook and sockeye salmon are found in the lower reaches of May Creek and in May Canyon; they most likely do not travel upstream as far as May,Yalley (King County 1995). Coho salmon and rainbow/steelhead and cutthroat trout rear in May Yalley and use it as a travel corridor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 0291A (upstream of proposed project) (King County 1995). Impact Analysis and Mitigation Plan 8 July 2011 May Creek Drainage Improvement Project -----------, Although we did not conduct a fOl1llalcensus offish in the surveyed reach of May Creek, we observed many schools of salmon ids during the August 2010 habitat survey (Appendix 8). Most schools were about 10 to 30 individual juvenile fish, and appeared to have both coho salmon and trout. [J.[l Wetlands Conditions One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990), is located in the project study area. This wetland is about 140 acres in total size; about 25 acres are contained in the project study area. The portion of the wetland located in the project area was delineated by King County wetland biologists in early 20 I 0, and the entire wetland was also rated at that time (King County 20 I Oa). May Creek #5 is a Category II riverine wetland with a 110-foot buffer under the King County Critical Area Code. The majority of the wetland is located in unincorporated King Couniy; however, the portion west of 148th Avenue SE is located in the City of Renton. Under the City of Renton Critical Area Code this is a Category 3 wetland with a regulatory buffer width of 25 feet. The wetland is located in the I OO-year floodplain of May Creek. Primary sources of hydrology to the May Creek #5 wetland are a combination of overbank flooding and a high groundwater table. While the wetland still received a high rating, it has been degraded over the years by adjacent fal1lling and agriculture. Many areas of the wetland. are actively mowed and used for grazing horses and other livestock. In the fal1ll areas on the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in the wetland over the years to allow pasturing. On the south side of the wetland, the wetland boundary more closely follows valley topography, and multiple groundwater seeps were visible on the valley walls at higher elevations. In the majority of the wetland not regularly mowed and maintained as pasture, the dominant vegetation was reed canarygrass, which grew as thick blankets with almost 100-percent coverage. The only unmowed areas without reed canarygrass were in the scrub- shrub/forested components of the wetland near May Creek where the reed canarygrass was shaded out. The width of the scrub-shrub/forested buffer along the stream was about 50 to 75 feet in areas 'where the reed canarygrass was shaded out (i.e., 25 to 37 feet wide on each side of the stream). 0.4. Oydcaulic Conditions May Creek valley experiences out of bank flooding that last several days to weeks at a time on a routine basis every wet season. The stream course is essentially in a bowl for . approximately 2100 feet (river mile 4.6 to 5.0) between a footbridge upstream of Parcel #0223059005 property down to Long Marsh Creek confluence where a sediment delta has built up, just upstream of another footbridge. Long Marsh Creek is primarily a forested basin with steep gradients. This characteristic gives the tributary the ability to Impact Analysis and Mitigation Plan 9 July 2011 May Creek Drainage Improvement Project I I I I I II I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I deposit gravels large enough such that May Creek is not capable to redistribute gravels downstream. Thus stream bed elevations at this location rise as more gravel is deposited. This accumulation causes May Creek to backwater upstream causing more deposition of fines and decaying vegetation subsequently reducing conveyance capacity and increasing frequency of valley flooding. Two types of models were used to perform hydraulic and hydrologic analyses for current conditions and proposed drainage improvement scenarios, HEC-RAS for hydraulics and HSPF (Bicknell 2005) for hydrology. Both models used were adapted from existing models and updated to reflect current conditions. HEC-RAS (USACE 2008) was used to evaluate channel conveyance capacities and flooding inundations, while HSPF was used to provide statis'tical measures of durations and magnitudes of events used for defining boundary conditions in the HEC-RAS model. The analysis shows that during mean annual flows (8.6 cfs through the study area), control points include vegetation choking points in the wetland downstream of 148th Avenue SE bridge and mildly so upstream of 148th Avenue SE and gravel deposition where Long Marsh Creek enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04. Similarly for flows above the one year event, Long Marsh Creek again controls water surfaces upstream for the same reach length. Downstream of 148th Avenue SE, hydraulic model runs show the natural constriction change from open wetland on valley floor to well defined channel entering into the ravine. controls storm events flows of one year return interval and greater. Removal of vegetation choke points in the wetland produce a few tenths of a foot change in water surface, within the range of model accuracy and very small amount oflost storage, this natural land form constriction downstream of the proposed restoration channel activities is the control for erosion in the ravine. Flows below the one year flood event would have a slightly longer duration but not higher velocity. The flows at these lower events are below levels that cause channel erosion below May Valley (AnchorQEA, 2010). Impact Analysis and Mitigation Plan 10 July 2011 May Creek Drainage Improvement Project May Creek Drainage Improvement Project Legend /'../ Willow (893') /'../ Willow/RCG Mix (580') /'../ Reed Canarygrass (RCG) (1360') '- " N + December 2010 tQ King County O;. .. ~75~~'~~======~~ ......... ~~======~~ • Feet The i'1brnIciort included on Ihi5 map ha5 been ~ by King County staff from. variety of sources and .. t.Ubted to change wthout notice. King County makft no representations Of wallantin, expr_ Of~. as to KCUfacy. ~M . timel.,.., Of righm to h use of such information. This document is not intended for use as a s.urvey product. King County sha. not be liable for any general, speciaL indirect, incidental. Of consequential da~ ilduding, but not IrMed to, bst revenues Of lost profits IKlJlting from the UIe Of misuse of the information contained on this map. Ally ulli of this map or Infofmation on this map i$ prohibited except by written permission of King County Figure 3 Existing Reparian and In-Stream Vegetation fI01IA.. ~l~·~....,o.I<lI __ r-~,," May Creek Drainage Improvement Project Legend • Study Area o River Mile Habitat Units /\/ GLD /\/ LGR /\/ LSP /\/ MCP /\/T /"y/ Streets /"y/ Streams .. Wetlands Cougar Mountain Wildland Park N + December 2010 ~ King County O;. .. OO ..... '80~=======~ ........ ~-========~~ • Feet The inform8tjon Included on this"...p I'Ias been compiled by King County mfJ from. variety at SOUfce. 80d is sub§ed to cn.nge wthout notice. King County IT'IiIkn no r~.aem.tions Of _rrantie5, expr .. Of~." to accwacy. OOIliplete.,ea.. trneinela. 01' rights to th<t 11M C1I such "'ormation. Thia document is not ntended few 11M as • awv., product. King County shal net be .. bIe for any ge".,..!. special. indirect, InCidental. Of conseq~1 darnagH inctuding , but not Mmited 10, bst !lw.nun Of lost pl'ofits !HUling from the use Of ITlISUM of the iotorm.tion contained on this map. Any sale of mis map Of InfoImatJon on this map IS pfonibited except by written permisSIOn of King County Figure 4 PO~l*·t:II«P""'~_I ___ 'GIS I I I I I I I I I I I I I I I I I I I 4. Impact Analysis The unavoidable stream and wetland impacts associated with the project are described in this section. 4.1. Stream Impacts As a result of vegetation and sediment removal, the aquatic and terrestrial habitat features within May Creek and its buffer may be temporarily or permanently degraded. Vegetation removal in these areas would degrade riparian habitat by reducing canopy cover, organic inputs, prey sources, bank stability, and future large wood recruitment. The stream would experience localized hydraulic changes within the project area when the willow and reed canarygrass removal and sediment removal occurs. These changes have the potential to modify fish habitat in May Creek, such as the locations and depths of pools, quantity and quality of coho and trout rearing and refuge habitat, and quantity oflocal spawning gravel. Impacts to Long Marsh Creek as a result of the sediment management activities include temporarily disturbed in-stream habitat and riparian buffer. These impacts are described in more detail below and are summarized in Table 2 at the end of this section. 4.1.1. Impacts from Sediment Removal Sediment removal would occur in May Creek from Station 5+40 to 26+26 (2,086 linear feet) and would have both short-and long-term effects on the stream. As part of the sediment removal, the stream channel would be excavated to a uniform elevation of 308 feet. The following list summarizes the potential impacts that could occur as part of the sediment removal operations: • removal of stream bank and aquatic vegetation • removal, release, or rearrangement of silts and sediments • reduction of water quality 1. remobilization of contaminants (if any were to exist in project area) 2. increased turbidity 3. increased erosion and sedimentation • alteration of fish habitat 1. elimination of habitat type (channel complexity) 2. alteration of fish-spawning habitat 3. alteration of benthic habitat 4. disruption or removal of benthic communities Several factors influencing the magnitude of the effects of dredging-type activities such as this include: size of the dredging operation, frequency of dredging, stream channel size and depth, size of material, background levels of water and sediment quality, Impact Analysis and Mitigation Plan J3 July 2011 May Creek Drainage Improvement Project suspended sediment, turbidity, stream velocity, design of final contours, and stability of channel up-and down-stream from the dredging operation. The list of impacts above may occur at May Creek. Sediment removal would occur along 72 percent of the proposed project area and would impact in-stream habitat, spawning habitat, water quality, and alter the timing and magnitude of silt and sediment migration. Sediment removal would have its biggest impact on Reach Two because this reach is well-connected with its floodplain, has some floodplain terracing, and is well vegetated. Sediment removal would reduce the stream's floodplain connection during smaller flow events and would remove functioning riparian vegetation. Sediment removal in Reach Three, which includes the alluvial fan of Long Marsh Creek, would temporarily disturb spawning gravels in May Creek. 4.1.2. Impacts from Vegetation Removal In combination with sediment removal impacts, the stream would also be negatively impacted by removal of in-stream and bankside willows and reed canary grass throughout the entire project area. Table I describes the type and location of vegetation removal associated with this project. Table 1: Type and Location of Vegetation Removal Type of Vegetation Removal Station Station As mentioned in the May Creek Drainage Improvement Baseline Stream Conditions Report (King County 2010b), in-stream habitat in the surveyed reach of May Creek is greatly influenced by riparian plant communities. Aquatic habitat is much more complex in places where the riparian corridor has woody plants, such as willows, actively engaged with the stream channel and connected floodplain. Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel. This is most evident when comparing reaches with just reed canarygrass versus reaches with native riparian vegetation, such as willows. In areas where reed canarygrass Impact Analysis and Mitigation Plan 14 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I dominates, such as Reach Four, the channel tends to be deeper and is 100 percent glide habitat. In Reaches One and Two, where some native willows grow along the stream banks and interact with the stream channel, some pools are also present. The proposed removal of willows (Table I) includes willows obstructing flow within the channel. This removal of willows actively engaged with the stream channel would reduce the number of pools within the surveyed reach of May Creek; it would also reduce or eliminate channel complexity within Reach Two. Six out of nine surveyed pools were formed by scour against willows. These six pools would be eliminated by the proposed project. Furthermore, dense willow branches crossing the stream in Reach Two function like a debris complex, creating numerous backwater areas during higher flows. As with pools, this habitat would be eliminated with willow removal. Willow removal would reduce pool formation and channel complexity. Eliminating these complexities would reduce available fish habitat. In addition to the removal of in-stream habitat components, willow removal would eliminate some streamside vegetation that shades the stream to maintain cool temperatures, and contributes organic debris and leaf litter, which support many stream food webs. This likewise would reduce fish (and other aquatic organism) habitat quality. Overhanging plants provide cover for fish rearing and seeking refuge along the streambanks. Over 80 percent of both streambanks have either reed canary grass or willows, identified as obstructing flow hanging over the channel (20 I Ob King County). Reed canarygrass, while undesirable from a native plant and diversity ecological perspective, does provide abundant cover for fish and it also shades the water to reduce water temperature. The entire project length would have its flow obstructing overhanging and in-stream vegetation removed. Fish and other aquatic organisms would lose the habitat provided by overhanging or in-stream vegetation until newly planted riparian areas can again begin to provide these needed functions after a few growing seasons. Typically these types of vegetation removal impacts would be considered temporary because the riparian area cleared would be replanted and would begin to provide the lost functions within a few growing seasons. However, in Table 2, these impacts were also considered permanent due to the lost functions that may not be restored within a few growing seasons. These permanent impacts include lost fish habitat from removal of reed canarygrass and willow. Willow branch complexes have taken 15 to 20 years to establish themselves in this manner and would not replicate pool-forming functions within a few growing seasons. Furthermore, the intent of the proposed riparian buffer plantings is to shade out reed canarygrass, thus the habitat function provided by reed canarygrass would be permanently lost and replaced by different types of vegetation (native plant species) that would likely provide different types of habitat. Impact Analysis and Mitigation Plan 15 July 2011 May Creek Drainage Improvement Project In addition, adjacent to Long Marsh Creek, sixteen trees over 6-inch dbh (primarily red alder) would be removed to reconstruct the channel for sediment management. This riparian buffer area would be replanted with native vegetation, but the temporal functional loss associated with removal of mature trees would take years to replace so this is being considered a permanent impact. 4.2. Wetland Impacts The proposed project would not permanently impact the wetland; however, there would be areas of temporary impacts within the wetland and wetland buffer. These consist of reed canarygrass and willow removal and construction of access roads. The primary wetland functions impacted include loss of grass and shrub habitat that may currently be used by birds, small mammals, amphibians, reptiles, and resident fish during certain times of the year. This project is not expected to change the amount of wet pasture or wetland in the project vicinity. Because ofthe high groundwater table in May Valley and no measureable difference in the geographical extent of overbank flooding (just the duration of flooding at the start and end of the rainy season) the wetland should not be affected. To confirm this; King County WLRD has installed five groundwater monitoring wells in various locations throughout the wetland to monitor pre-and post-project groundwater levels. Impact Analysis and Mitigation Plan 16 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I ------------- ---- - Table 2: Summary of Stream and Wetland Impacts Resource Resource Impact Area Type May Creek TypeF 45,300 square feet*· Channel May Creek TypeF 14,500 square feet""" Vegetation May Creek TypeF 14,500 square feet"*" Vegetation May Creek TypeF May Creek Floodplain May Creek TypeF . May Creek Sediment Transport Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan 17 Impact Type Functional Impact Permanent Impact Alteration of stream channel resulting in the loss of Excavation of sediment and reshaping in-stream habitat and complexity. of the May Creek channel. Permanent Impact Loss of in-stream habitat including fish rearing Removal of in-stream and overhanging habitat and six pools formed by willow branches. willow and reed canarygrass Temporary Impact Loss of hiding cover, loss of thermal cover, loss of Removal of in-stream and overhanging bank stability, loss of surface water runoff filtration willow and reed canarygrass until buffer planting is established. Permanent Impact The reduced connection of May Creek to its Reduced connection between May floodplain in May Valley will result in loss of off- Creek and the floodplain. channel rearing and refuge habitat for coho salmon and trout during smaller flow events. Temporary Impact During construction and during the first storm event Increased sediment transport fter the construction is complete, the following downstream to May Canyon and Lake mpacts may occur: Washington. I. Increased turbidity. Spawning gravels or salmon redds covered with and or silt (fines). j. Increased deposition in the alluvial fan in Lake Washington (fines). July 2011 - Table 2 Continued Resource Resource Impact Area Impact Type Functional Impact TYPe May Creek Category 5,922 square feet Temporary Impact Disturbance to existing wildlife habitat (mostly rced Wetland #5 II Fill for construction access roads. canarygrass), soil compaction. Buffer' Wetland 8,992 square feet Temporary Impact Disturbance to existing wildlife habitat (mostly reed Stream Fill for construction access roads. canarygrass and pasture grasses), soil compaction. May Creek/ TypeF 60 linear feet Temporary Impact Disturbance to existing in-stream habitat, including Long Marsh Excavation of gravels and change in an existing pool at the confluence. Creek channel geometry at the confluence. Confluence Long Marsh TypeF 16,520 square feet Temporary Impact Disturbance of existing stream habitat: Buffer Stream channel excavation, removal of I. Loss of shade 16 trees over 6" dbh (primarily red 2. Loss of habitat alders) as well as ground cover. 3. Creation of new off-channel habitat. • Wetland and stream buffers overlap throughout the project area so for simplicity wetland buffer and stream buffer impacts have been combined . •• This area calculation is based on the width from top of bank to top of bank for the entire length of proposed sediment removal. ••• The area was calculated by using 5,800 linear feet (2,900 linear feet on each bank) and assuming 2.5 feet of disturbance on each bank as part ofthe invasive vegetation removal. Willow removal is also included in this overall impact area. Impact Analysis and Mitigation Plan 18 July 2011 May Creek Drainage Improvement Project - ------------ ------ ------ I I I I I I I I I I I I I I I I I I I 5. Mitigation Approach 5.1. Impact Avoidance and Minimization King County has designed the project to avoid and minimize impacts to wetlands, streams, and buffers to the greatest extent possible. Total avoidance through design was not possible because the purpose of the project is to reduce the duration of flooding on local property owners by removing in-stream channel obstructions. To avoid and minimize impacts during construction, appropriate Best Management Practices (BMPs) would be used. Proposed construction limitations and BMPs include the following: I. Construction would comply with the King County (2009) Surface Water Design Manual for erosion and sediment-control features. Erosion-and sediment-control features include the use of ground covers such as plastic, fabrics (jute, excelsior, woven straw, or synthetic fiber), hydroseeding, sediment traps, silt fences, check dams, inlet protection and other proven techniques for minimizing erosion and sedimentation. The temporary sediment and erosion control (TESC) plan prepared for the project would include standard BMPs as well as site-specific measures to prevent and control erosion within the project area. 2. A Spill Prevention Control and Countermeasures (SPCC) Plan would be prepared prior to start of construction to address specific potential sources of spills, spill prevention and containment methods, spill response procedures and on-site materials and equipment, reporting, site security measures, and inspection procedures. 3. When practicable, all equipment fueling and maintenance would occur outside the wetland, stream, and buffer. All vehicles operated within sensitive areas would be inspected daily for fluid leaks before leaving the vehicle staging area. Any leaks detected would be repaired before the vehicle resumes operation. When not in . use, vehicles would be stored in the vehicle staging areas outside the buffers. 4. The contractor would install temporary high-visibility fencing and silt fencing to demarcate and protect critical areas in the approved TESC plan. Any work that is required in critical areas would only be done at the engineer's direction and per the design plans. When the fencing is no longer needed, or at the engineer's direction, the contractor would completely remove and dispose of temporary high-visibility fencing and silt fencing. 5. Whenever possible, construction equipment would use existing farm access roads to cross the wetland and access the stream. 6. When wetland or stream access is needed outside of existing farm roads tracked or rubber tired machinery would be used to minimize ground disturbance and to Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan 19 July 2011 avoid the need to construct additional access roads. Direct access to the stream channel by equipment would only be allowed in specific areas where disturbance to vegetation can be minimized and removal of mature trees can be avoided. 7. In-water work would be done during low-flow stream conditions, in accordance with the regulatory in-stream work window. 8. During the sediment removal, the stream would be temporarily diverted around the work area as part of the temporary erosion-and sediment-control plan. This diversion may involve using one or more gas-powered pumps to remove water from the channel just upstream of the work area. The water would then be discharged downstream of the work area, in a safe, non-erosive manner. 9. May Creek would be protected during construction of the off-channel alcoves by leaving an earth plug between the existing stream channel and the excavation area for the alcove. Prior to removing the earth plug and connecting the alcove to the existing channel, a turbidity curtain would be installed to protect the stream from sediment and turbidity during the connection. A more detailed description of construction BMPs can be found in the project's Construction Wa'ter Quality Protection and Monitoring Plan (King County Juiy 2011). 5.2. Compensatory Mitigation Impacts that cannot be avoided and minimized must be compensated for by constructing compensatory mitigation. The majority of the impacts to May Creek, Long Marsh Creek and the associated wetlands would occur in unincorporated King County, while the compensatory mitigation would be constructed in both King County and the City of Renton. 5.2.1. Mitigation Ratios The wetland impacts associated with this project are all temporary, and all the impacted wetland areas would be restored to equivalent or better function after construction. For this reason, mitigation ratios for wetlands were not applied to this project. King County and City of Renton mitigation requirements for streams are approximately equivalent (King County Code 21 A.24.380 and City of Renton Municipal Code 4-3-050- Ll), with King County Code being slightly more stringent. For this reason, and because the majority of the stream impacts are located in King County, King County mitigation ratios are referenced in this report. The King County Critical Area Code specifies that any mitigation for impacts to streams must achieve equivalent or greater functions. Typically a I: I mitigation ratio is applied for in-kind stream mitigation performed onsite; however, the project cannot offer onsite in-kind stream mitigation because adding Impact Analysis and Mitigation Plan 20 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I mitigation in the May Creek channel conflicts with project goal of flood reduction. For this reason, onsite out-of-kind mitigation in the form of riparian buffer and wetland enhancement is being proposed to compensate for in-stream impacts. King County and City of Renton code does not provide specific mitigation ratios for out-of-kind mitigation, but because out-of-kind mitigation replaces different functions from those that are impacted, the replacement ratios typically must be higher in order for mitigation to achieve equivalent or greater functions. For this project, the proposed replacement ratio is approximately three acres of wetland enhancement for one acre of in-stream impact to the May Creek channel (3:1 ratio). The proposed replacement ratio for impacts to in-stream and riparian vegetation is approximately two acres of riparian buffer planting for 113 acre impact to May Creek vegetation (6:1 ratio). The proposed replacement ratio for impacts to trees along Long Marsh Creek is approximately 2 trees replanted for each tree removed (2: I). 5.2.2. Mitigation Functions The proposed compensatory mitigation (Table 3) is focused on enhancing wetland and riparian habitat functions in May Valley. The wetland enhancement includes off-channel alcoves that would increase fish habitat complexity in the wetland during high flows and would partially replace some in-stream habitat functions lost due to the in-stream sediment and vegetation removal. The wetland enhancement also includes suppression of reed canarygrass and replanting of native vegetation, which would improve general wildlife habitat complexity in May Valley. The riparian buffer planting would improve buffer function in the long-term by minimizing reed canary grass infestation and providing native vegetation that would shade the stream, provide bank stability, capture sediment from pasture runoff, and provide wildlife habitat. The riparian buffer plantings would be installed in many areas where only reed canarygrass or pasture grass currently exists. While the proposed mitigation does not provide the same functions as those being impacted (impacted functions are primarily in-stream habitat while mitigation is focused on wetland/riparian habitat function), it does provide an improvement over existing conditions over a large area (approximately 5 acres total). A more detailed discussion of the functions provided by the mitigation is provided in Section 5.5. The mitigation proposed for this project is summarized in Table 3. Impact Analysis and Mitigation Plan 21 July 2011 May Creek Drainage Improvement Project. - --------------- Table 3: Mitigation Ratios and Proposed Mitigation Areas Impacted Impact Resource Area May Creek 45,300 square feet Channel May Creek 14,500 square feet Vegetation May Creek May Creek Floodplain May Creek Sediment May Creek Transport May Creek 5,922 square feet Wetland #5 Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan Impact Proposed Type Mitigatiou Permanent 3 acres of out-of-kind wetland enhancement west of Excavation of sediment and 148th Avenue SE including off-channel alcoves, reed reshaping of the May Creek canary grass suppression, replanting with native channel. vegetation, and LWD placement. Permanent and Temporary 2 acres of riparian/wetland buffer planting for 15 feet Removal of in-stream and on both sides of May Creek, protected by fencing (to overhanging willow aud reed restrict livestock access) and permanent conservation canarygrass. casements. Permanent Compensation is included in the 3.0 acres of propos cd Reduced connection between May wetland enhancement west of 148th Avenue SE by Creek and the floodplain constructing off-channel alcoves to provide fish habitat during higher flows. Temporary Off-channel alcoves in the wetland enhanccment area Increased sediment transport would provide sediment storage for the temporary downstream to May Canyon and Lake Washington. pulse. Temporary Construction access areas would be restored to previous condition using native plants or appropriate Fill for construction access roads. seed mixes. 22 July2011 --- Proposed Replacement Ratio 3:1 6: I Includcd in the 3: 1 ratio above. Included in the 3: I ratio above. Area would be restored. ------ Table 3 Continued Impacted Impact Impact Proposed Proposed Resource Area Type Mitigation Replacement Ratio Temporary Construction access areas would be restored to Arca would be Buffer* 8,992 square feet previous condition using native plants or appropriate Fill for construction access roads. restored. seed mixes. May Creek/ Temporary Channel and confluence would be reconstructed and Long Marsh 16,520 square feet Excavation of gravels in May restored to include a wider channel with streambed Area would bc Confluence Creek and change in channel gravels, and LWD. restored. geometry at confluence. Permanent Area would be Long Marsh 16,520 square feet Stream channel excavation, Buffer replanting with 32 trees, 150 willow stakes, and restored. Buffer (16 trees greater than removal of 16 trees over 6" dbh 156 shrubs, and 282 emergents / groundcover. Trees Replaced 6-inch dbh removed). (primarily red alders) and groundcover. at a 2: I Ratio ·Wetland and stream buffers overlap throughout the project area so for simplicity wetland buffer and stream buffer impacts have been combined. Impact Analysis and Mitigation Plan 23 July 2011 May Creek Drainage Improvement Project ------------------- I I I I I I' I I I I I I I I I I I I I 5.3. Compensatory Mitigation Goals The mitigation goal for this project is to achieve no overall net loss in habitat functions in the May Creek subbasin. 5.4. Compensatory Mitigation Objectives The objectives listed in this section were selected after analyzing multiple potential mitigation alternatives. Some of the mitigation alternatives considered but not selected included: • In-stream LWD: Enhancement to in-stream habitat by placing L WD in the stream channel was considered, but this option was eliminated because placing LWD in the channel is counterproductive to the primary project goal of removing flow obstructions. As a compromise, L WD would be placed in off-channel alcoves adjacent to the stream where it would not obstruct flow, but would provide habitat during higher flows (see Objective 1 below) and would also be placed throughout the wetland enhancement area. • Side Channels/Floodplain Terraces: Creation of side channels and/or floodplain terraces in the open space area west of 148th Avenue SE was considered, but this option was eliminated due to the lack of elevation change and potential for sediment accumulation on this property. The lack of elevation change and sediment accumulation posed a potential risk of fish stranding in side channels and terraces during the summer low-flow. . The final mitigation objectives for the project include: 1. -Objective 1-Wetland Habitat: Enhance approximately three acres of riverine wetland on the west side of 148th Avenue SE to increase fish habitat complexity during high flows and general wildlife habitat complexity year-round. Enhancement would include: a. Construction of approximately 0.24 acres of off-channel alcoves along May Creek with emergent wetland vegetation, LWD (16 pieces), two snags, and streambed gravels. b. Suppression of approximately three acres of reed canary grass using weed fabric, planting of native wetland vegetation, and placement ofLWD (60 pieces). 2. Objective 2 -Riparian Habitat: Enhance approximately two acres of riverine wetland/riparian buffer by suppressing invasive species and planting a IS-foot wide fenced buffer of native vegetation along both banks of May Creek Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan 24 July 2011 throughout the project limits (approximately 2,900 linear feet) east and west of 148th Avenue SE. 5.5. Compensatory Mitigation Description I Design Compensatory mitigation for temporary wetland impacts and permanent stream impacts along May Creek would focus on restoring wetland and riparian habitat in May Valley. Please note that in the majority of the project area, the stream buffer for May Creek is contained within the delineated wetland boundary. For this reason the riparian enhancement could also be considered wetland enhancement, but they are discussed separately below. 5.5.1. Riparian Enhancement Area The riparian enhancement area encompasses a 15-foot wide planting area along each side of May Creek for the entire project length (approximately 2,900 linear feet) for a total of approximately two acres. In planting areas where reed canarygrass is the dominant vegetation, the grass would first be mowed if necessary, and covered with a weed barrier fabric intended to shade out the grass in the short-term. The new plants (primarily trees and willow stakes) (Appendix A - Sheet 18) would be planted through the temporary weed barrier fabric. This would improve long-term function of the riparian area as a whole by establishing populations of tree and shrub species that would, in time, serve as perches, nesting habitat, snags and provide a native seed bank. Establishing vegetation would also create a dynamic stability to the stream bank and would help filter out sediment that is suspended in runoff from the adjacent farms and pastures. 5.5.2. Wetland Enhancement Area The wetland enhancement area is located on the west side of 148th Avenue SE (Appendix A -Sheet 14) in a designated open-space tract in the City of Renton owned by the Stonegate Homeowners Association. In addition to the riparian buffer planting described in the previous section, approximately three more acres of enhancements would be constructed on the west side of 148th Avenue SE and include: I. In-stream Enhancements: Approximately 0.24 acre of off-channel alcoves would be constructed along May Creek in the wetland on the west side of 148th Avenue SE. The existing banks would be replaced with a terrace (wide bench) and gradual slopes. Within this terrace, an alcove would be created that incorporates woody debris (Appendix A -Sheet 14) and streambed gravels would be placed for the first 15 feet adjacent to May Creek. Jute matting would be placed in the alcoves beyond 15 feet to minimize erosion, and the alcoves would be densely planted with emergent and scrub-shrub wetland plants. This would increase the amount of available instream habitat and would decrease flow velocities, thus improving the Impact Analysis and Mitigation Plan 25 July 201 I May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I quality of off-channel overwintering habitat. During a flood, water would inundate the terrace and interact with the woody debris and vegetation. Sediment deposition would occur outside of the main channel in the alcoves. The woody debris and vegetation would trap and hold sediment and then allow a more gradual pulsing of sediment back into the channel over time. This mitigation would improve winter rearing habitat for salmonid and other fish species in areas adjacent to the mainstem of May Creek. The mitigation would increase biological functions for riparian species within May Creek through introduction of woody debris; woody debris would also provide substrate for invertebrates, hiding habitat for juvenile fish, perching habitat for riparian birds, and desirable niches for river otters, other mammals, and crustaceans. The proposed mitigation is also designed to enhance refuge and rearing habitat through the establishment of habitat features along May Creek. Such enhancements would make these habitat features available to salmonids and other wildlife species at a wider range of flow rates on May Creek. In addition, willows and other native shrubs would be planted along streambanks and confluence margins to increase cover of overhanging branches above the waterways. Lastly, the removal of reed canarygrass and root system from the floodplain would create additional area for sediment deposition, thereby allowing some decrease in fines downstream. 2. Wetland Habitat Enhancements: In addition, to the 0.24 acres of off-channel alcoves, approximately 2.75 acres of wetland habitat enhancement would occur on the west side on 48th A venue SE. In this area, reed canarygrass would be suppressed using a weed barrier fabric and native vegetation (cottonwood, willow, and dogwood) would be planted through the fabric. LWD (76 pieces) would also be placed throughout the wetland. These activities would improve the wildlife habitat complexity in the wetland, providing habitat for mammals and riparian birds. It would also increase the native seed bank in May Valley and provide a future source for LWD. Impact Analysis and Mitigation Plan 26 July 2011 May Creek Drainage Improvement Project 6. Performance Standards, Monitoring, Maintenance, and Contingencies King County WLRD would provide monitoring services during and after construction of the proposed project. 6.1. Performance Standards I. Regulated Noxious Weeds: If noxious weeds are discovered during monitoring, they would be treated according to currently established standards. 2. Invasive Weeds: The percentage of buffer and wetland planting areas covered by non-regulated invasive weeds would not exceed ten percent through the monitoring period, except for reed canarygrass. Due to the existing 100-percent coverage of reed canarygrass in the project area, it would not be possible to achieve less than ten percent coverage of this species during the monitoring period. Over the long-term, reed canarygrass would be reduced in density by meeting the Vegetation Coverage performance standard below. 3. Vegetation Coverage: Within the wetland and buffer planting areas, woody native vegetative cover shall be 65% by the end of the monitoring period. 4. Vegetation Survival: Within the wetland and buffer planting areas, qualitative inspections for plant replacement would be conducted annually by an ecologist during the monitoring period, and plants would be replaced as needed to ensure that coverage performance standards are met. 6.2. Monitoring Construction Monitoring Construction-phase monitoring would focus on protection of water quality and important vegetation that is to be preserved. King County WLRD prepared a Construction Water Quality Protection and Monitoring Plan (King County July 2011) which describes the construction monitoring techniques and best management practices that would be utilized to monitor and protect water quality. Post-construction Monitoring Vegetation would be monitored throughout the ten-year monitoring period. Post- construction monitoring would be conducted to establish whether performance standards for the mitigation have been met. Monitoring reports would be submitted at the end of years three, five, seven, and ten. These reports would describe and, to the extent possible, quantify the level of success of the mitigation. Data collected on physical and biological Impact Analysis and Mitigation Plan 27 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I ,---------------- I I I I I I I I I I I I I I I I I I I parameters would be compared to the established performance standards defined in Section 6.1. 6.3. Maintenance All planted areas would be watered through the first year of installation as needed. Other maintenance activities would be performed for ten years as needed, including weeding, watering and fabric maintenance. After vegetation has matured enough to reduce the reed canary grass density (about two to three growing seasons) the weed fabric would be removed by hand. 6.4. Protection The mitigation areas would be fully fenced to restrict livestock access and would be demarcated with wetland protection signage. King County would also protect the mitigation areas in perpetuity by recording a conservation easement, or similar document, on the title of each property. 6.5. Contingencies Based on the data collected during annual monitoring of the completed mitigation site, it may be necessary to implement contingency measures to ensure that the established mitigation performance standards are met. These include mitigation objectives for plant survival, vegetation cover, and amount of invasive species, all of which help to define viable riparian fun~tions. Several factors, both artificial and natural, could have detrimental effects on the successof the mitigation sites. These factors include changes in hydrology from drought or flooding, water pollution from excessive nutrients or toxicants, erosion of soil during flood events, plant mortality, and competition from invasive plants. King County would commit to the maintenance, monitoring, reporting, and the replacement of dead plants as required to meet the established performance standards for plant cover and survival and for measures to control invasive species. Impact Analysis and Mitigation Plan 28 July 2011 May Creek Drainage Improvement Project ._-------------------------------- 7. References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. Bicknell, Brian, et aI., July 2005. HSPF Version 12.2 User's Manual. Prepared for U.S. EPA-NERL. Prepared by Aqua Terra Consultants. King County. 20 II. Construction Water Quality Protection and Monitoring Plan. July 2011. Prepared by King County Department of Natural Resources and Parks. Seattle, Washington. King County. 2010a. May Creek Channel Restoration Project Wetland Delineation Report. March 10, 20 I O. Prepared by King County Road Services Division Environmental Unit for King County Department of Parks and Natural Resources. Seattle, Washington. King County. 20 lOb. Baseline Stream Conditions May Creek Drainage Improvements CIP# 9AI205 Revised December 2,2010. Prepared by King County Road Services Division Environmental Unit for King County Department of Parks and Natural Resources. Seattle, Washington. King County. 2001. Final Adopted May Creek Basin Action Plan. King County. 1995. May Creek Current and Future Conditions Report. August 1995. Prepared by Foster Wheeler Environmental Corp, King County Surface Water Management Division, and City of Renton Surface Water Utility. USACE, March 2008. HEC-RAS, River Analysis System-Hydraulic Reference Manual (Version 4.0). Washington Dept. of Fisheries (WDF). 1975. A Catalog of Washington Streams and Salmon Utilization, Volume I Puget Sound. Washington Department of Ecology (Ecology). 2004. Washington State Rating System for Western Washington. Publication No. 04-06-025. Olympia, Washington. Impact Analysis and Mitigation Plan 29 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I .' I I I I .1 II I I I I I I 09056 I 01-201 SURVEYED KING COUNTY 01 2010 SURVEY BASE ~ING COUNTY 02 2010 TREVOR CRAY, PLS 02-2010 CHECKED: DAlE NELSON 02-2010 HUM. V10NITY MAP ~ COALFIELD INDEX SHEET DESCRIPTION 1 . VICINllY MAP AND INDEX PROJECT "LOCATION 2. LEGENDS AND ABBREVATIONS 3. SUMMARY AND QUANTITIES (droft version) o 4. EXISTING CONDITIONS, SHEET KEY, LEGEND, CONSTRUCTION NOTES 5. TEMPORARY EROSION AND SEDIMENT CONTROL PLAN AND LEGEND 6. TEMPORARY EROSION AND SEDIMENT CONTROL PLAN 7. TESC SEDIMENT DISPOSAL AND PUMPING LOCATIONS (droft version) 8. TEMPORARY EROSION AND SEDIMENT CONTROL NOTES AND DETAILS 9. TEMPORARY EROSION AND SEDIMENT DETAILS 10. PLAN AND PROFILE STA. 0+00 TO STA 8+00 11. PLAN AND PROFILE, STA. 8+00 TO STA. 16+20 12. PLAN AND PROFILE, STA. 16+20 TO STA. 24+00 13. PLAN AND PROFILE, STA. 24+00 TO STA 29+00 END OF PROJECT 14. WETLAND AND RIPARIAN MITIGATION PLAN . 15. CROSS SECTIONS AND HABITAT MITIGATION DETAILS 16. CROSS SECTIONS AND HABITAT MITIGATION DETAILS 17. FISH HABITAT ENHANCEMENT INSTALLATION DETAILS AND NOTES 18. PLANTING PLAN APPRO'JED: DON ALTHAUSER. P .E. 7 2011 PRo.£CT KCFCZD No. I.IANAGER: DOUG CHIN 7 2011 PROJECT No. DESIGNEOo DALE NELSON 17/2011 SURVEY No. DESIGN ENTERED; M. RADEllA I 7 (2011 I ~~15~~E "'ON I BY I DATE 9A1205 • tQ King County Department of Natural Resources and Parks Water and Land Resources Division Stormwater Services Section Capital Services Unit Christie True, Director Department of Natural Resources and Parks MAY CREEK DRAINAGE IMPROVEMENT SE May Valley Rd. + 148th Ave SE MAY CREL< DRAINAGE IMPROVEMENT ~ King County Department of Natural Resources and Parks Water and Land Resources DiviSion S\onnwater Services Section capital Service. Unit VICNTY MAP />K) NlEX Christie Trw, DIr8ctor SHEET 1 OF 18 SHEETS 2006-16 I EXISTIN!:i DESCRleTION SYMBOL QcS~RIPIlQ~ SYMBOL I OES!!:!N LE~E~Q • MONUMENT IN CASE (MIC) ---------EXISTING DRIVEWAY, EDGE W$'&f//~~ a HUB AND TACK OF ASPHALT SEDIMENT REMOVAL AREA I' --PROPERlY LINE It REBAR AND CAP KING COUNTY ,4'no)1/i iid6 6J IN-STREAM WILLOW PRUNING AREA HW OHW---O.H.W.M. LINE -----PlAIffiNG MmGATION UNE ('5' BUFFER) • BERNTSEN NAIL --X--y--,:--x--x-FENCE-WIRE. BARBED WIRE, sPur RAIL I " fORMER FENCE POSTS, GATE POSTS , , , , , , GUARDRAIL -EXISTING lOGS I =:.=::=::=::=::= TOE OF CHANNEL -MAY, LONG 0) UTILITY POLE WITH OR WITHOUT MARSH, AND INDIAN MEADOW CREEKS UNDERGROUND CONNECTIONS T GUY WIRE --ROCK RETAINING WALL AT TSEGAY ENTRANCE WERlDWf ~ ~ ---:----W.S.LG.N.Z. , SIGN NAD 63/91 .' 3 TElEPHONE RISER , ~w ____ w ____ w ____ EXISTING WETLAND BOUNDARY " WATER VAlVE 1IA I ABBREVIATIONS It LARGE ROCK/BOULDER ... _-------_.-.. _-EXISTING WETLAND BUFFER ABBREVIATION DEFINITION () SEC SECTION -_,1_"-EXISTING STREAt.! BUFFER TOWNSHIP NAVD 88 TREE DECIDUOUS lWN I f----------100 YR. flOODPlAIN UNE R. E RANGE EAST W.M. WllLAMETTE MERIDIAN STA. STATlON , I • R-O-W RIGHT OF WAY SNAG (DEAD lREE) r'V~ -:.. .... TREE BUSH/SHRUB I, I y~ lREE EVERGREEN "'\ It ' I TEMPOBARY EROSIQN SEDIMENIATIQN I ~ !;!~BIEI!Q~ CONTROL .srMf!Ql. !;!~BIE1IQH JP§M&ili8lliJ CONSTRUCTION ACCESS ROAD I I \' ' ....... m .... ...... .. ...... : ............ : ...... STAGING AREA SPOILS AREA .. .... .. ........ .. .. ................ "" .......... . . . c&G ClEARING AND GRADING UMITS NOTES: WEIGHTED SilT CURTAIN 1. PARCEL UNES SHOWN ARE KING COUNTY GIS PARCEL UNES AND ARE I SHOWN FOR VISUAL PURPOSES ONLY. THESE PARCEL UNES ARE NOT SILT FENCE ACCURATE ENOUGH TO BE USED FOR PURPOSES OF SURVEYING. DEED • • • • • TAKES. OR PNY OTHER lAND TRANSACTIONS OR DEUNEATIONS. 2. BASIS OF BEARING FOR THIS PROJECT IS NZ01'12"E, THE INVERSE BETWEEN KING COUNTY CONTROL POINTS 3871 (N188995.987. E1316685.925) AND I 3705 (N'91108.582. E13'6760.44')(NAO 83/9' COORDINATE VALUES). 3. BENCH MARK IS KING COUNTY CONTROL· POINT NUMBER 3871, WITH A NAVD88 ELEVATlON OF 405.42. I I _. 7/2011 SHEET 09056 01 2010 ~ APPRO\m: DON ALTHAUSER, P .E. ti King County MAY U£EK DRAINAGE IMPROVEMENT 2 RElD BOOK: KCFCZO No. KING COUNTY 01-2010 PRO.JECT DOUG CHIN 7/2011 SU~ WAHAGER: Department of Natural Resources and Parks OF SURVEY BASE ~lNG COUNTY PROJECT No. 9A1205 Water and Land Resources Division 02 2010 ~ 18 7/2011 ___ DALE NELSON SURVEY No. TREVOR CRAY, PLS 02-2010 O<SIGHEI>. capltel serv\ces Unit I..SCEN:)S />H) AllBFE'llA11ONS SHEETS DALE NELSON 02-2010 -CHECKED: -7/2011 MAJNTENANCE Christie True, DirfK:1or 0ESI(J4 EHTERm: M. RADEllA DIVISION No. 4 2006-16 Nuw·1 RNsroN BY OATE I I I I I' Ii I .' I I I I I .' I I I I I PROJECT LIMITS: LENGTH: x x ITEM NO. TOTAL OUANTITY UNIT STD. ITEM NO. l. Nnn:-· ~nR ~c~,.. .. or FlElD 8001<: 09056 01-201 SURVEYED: KING COUNTY 01-2010 SUIM'r BASE ~ING COUNTY 02-2010 TREVOR eRAY, PLS 02-2010 CHECKED:. _DALE NELSON 02-2010 NUl.!. ITEM PlEPAAA: <¥WlNl IlRAI'IACE SiluCm.FES cae!!: .eA' .T PA'IB9IT BIOSION -. - ;1 ---.£JgON BY I DAlE PROJECT NUMBERS x PRo.ECT WAN"GER: DOUG CHIN DESIGNED: DALE NELSON DESIGN EHTtRED: M. RADEUA SUMMARY OF QUANTITIES , AS-BUILT ;;;ox: 7 2011 KCFCZD No. 7 2011 PROJECT No. 9A120S 7/2011 SURVEY No. 7/2011 MAINTENANCE DIVISION No. 4 ITEM NO. TOTAL QUANTITY UNIT STD. ITEM NO. ITEM na.t!! tQ King County . Department of Na1l.IraI Resources and Parks Water and land Resource5 Division Stonnwater Services section Capital SefYIca Unit Clrrfstie True, DImctor PROJECT NUMBERS AS-BUILT MAY CH£L( DRAINAGE IMPROVEMeolT SHEET 3 OF 18 SlIoIotARY OF OUANTITES SHEETS 2006-16 1 I I 1 I Ii I I 1 I, I ,I Ii I~ .' I I: I 1 -------------------SEC. 2, TWN.23, R. 5 E, W.M. DESIGN ! FGENO ~#L2W/h0\ SEDIMENT REMOVAL AREA = ---------- IN-STREAM WILLOW PRUNING AREA WETlAND BUffiR (110') PER KING COUNTY CAD REGULATION (FOR PURPOSES OF THIS PROJECT ONLY) EXISTING LEGEND -'-'- - ------DRIVEWAY UNE ~-~ --x --)' -~-FD<C£ • suRVEY CONTROL ~~-PROPERTY UNES ~~~~~~~~-"R o-w UNES STREAM BUffiR (165') PER KING COUNlY CAD REGULATION (FOR PURPOSES OF THIS PROJECT ONLY) _'>11 W ------DEUNEATED WE11.AND --PlANTING MmGATlON UNE (15' BUFFER) HOLD PRECONSTRUCTION MEEflNG. \ \ ESTABLISH REQUIRED SIGNAGE AND TRAFFIC PlAN REQUIREMENTS PS APPROVED BY KING COUNTY ENGINEER. STAKE OR FlAG THE LIMITS OF CONSTRUCTION. SEE NOTES 13, 16, AND 17 FOR CONSTRUCTION UMITS. LOCATE AND MARK UTILITIES INSTALL TEMPORARY EROSION CONTROL MEASURES SHOWN ON SHEETS 5 TO 9. INSTALl CONSTRUCTION ACCESS RAMP AND CONSTRUCTION ENTRANCE PAD AS NEEDED AND APPROVED IN THE FlELD BY ENGINEER. INSTALL STAGING AND TURN AROUND AREAS AS APPROVED IN THE FlELD BY THE ENGINEER. TO MINIMIZE DISTURBANCE TO EXISTING NATIVE VEGETATION, MACHINERY ACCESS ALONG THE STREAM WILL ONLY BE ALLOWED APPROXIMATELY EVERY 50 FEET AS SHOWN ON SHEETS 5 AND 11. MIl} , . ~~ '~~ REMOVE FLOW OBSTRUCTING WIllOWS AS DESCRIBED IN NOTES 13 TO 15. .....,. i , '" '-..::. ::--.... ~. \.--. ~ ~ , . REMOVE SEDIMENT AND REED CANARY GRASS AS DESCRIBED IN NOTES 1 6 TO 21. • -' I~ ~ " --.,...-.....---:------ 1. REMOVE ANY TEMPORARY CONSTRUCTION ENTRANCES AND ACCESS ROADS THAT ARE NOT _ I ,I'; ~~ ,". \: -Mt~~~~~\ . NEEDED FOR MITIGATION CONSTRUCTION . I -. I( / -r--. "::~~ ~ ,-, __ ~, __ '~~-''''~\\~''''''--"" "'~~, 2. CONSTRUCT MmGATION AND REVEGETATE AS SHOWN ON SHEETS '4 TO 18. ;', { {T~~"'bt:'::'::-' '\ ~'\ \..\ '....~ I \ f /~·=-tooO&.=u!Jll,~~, __ -......~ \ " IN SELECTED LOCATIONS FROM STA 0+00 TO STA 5+40; SEE TABLE ON SHEET 10 AND DETAIL SHEET 15. 4. WILLOW BRANCHES AND ROOTS THAT ARE lIMITlNG THE STREAM flOW WILL BE REMOVED BY HAND AND/OR HANDHELD SMALL MACHINERY TO MINIMIZE DISTURBANCE. WILLOW BRANCHES THAT ARE NOT UMmNG STREAM FLOW WILL NOT BE REttAOVED. EXACT WIllOWS TO BE REMOVED WILL BE DIRECTED IN THE FIELD BY THE ENGINEER OR ECOLOGIST. WOODY NATIVE VEGETATION THAT IS REMOVED WILL BE MULCHED AND SPREAD OVER REED CANARY GRASS TO SHADE OUT GRASS /IS DIRECTED IN THE FIELD BY THE ENGINEER OR ECOLOGIST. FROM STA 5+40 TO STA 26+26 Will OCCUR IN SELECT LOCATIONS FROM STA 0+00 TO STA 29+00. SEE TABLE ON SHEET 10. MACHINERY FOR REMOVING SEDIMENT AND REED CANARY GRASS SHALl BE OPERATED FROM THE BANK. SEDIMENT AND REED CANARY GRASS REMOVAl SHAll BE DONE IN THE DRY. A STREAM BYPASS PLAN SHALL BE SUBMIlTED TO THE ENGINEER IN ADVANCE OF INSTALLATION FOR FINAL APPROVAl. PRIOR TO INSTAllATION OF THE BYPASS THE KING COUNTY ECOLOGIST Will REMOVE FISH FROM THE CHANNEL DO NOT INSTALL THE BYPASS UNTIL YOU HAVE BEEN GIVEN PERMISSION BY THE KING COUNTY INSPECTOR TO DO SO. EXCAVATE SEDIMENT AND/OR REED CANARY GRASS FROM NOW ORY CHANNEL . RETURN FLOw TO CHANNEL UNDER DIRECTION OF ENGINEER/ECOLOGIST. SEE NOTES ON SHEET 8 RELD BOOK: 09056 APPROI£D: WN Al..1HAU:St.t<, I".t.. PRO.£CT KCFCZO No. ~~. / --.. .... ..: /c=r ~~ ( ! ~ '\ \. I / ~ \ , NOTES: 1. PARCEl UNES SHOWN ARE KING COUNlY GIS PARCEL UNES AND ARE SHOWN FOR VISUAl PURPOSES ONLY. THESE PARCEL LINES ARE NOT ACCURATE ENOUGH TO BE USED FOR PURPOSES OF SURVEYING, DEED TAKES. OR ANY OTHER LAND TRANSACTIONS OR DEUNEATIONS, 2. BASIS OF BEARING FOR THIS PROJECT IS NT01'12"E. THE INVERSE BETWEEN KING COUNTY CONTROL POINTS 3871 (NI88995.987, E1316685.925) AND 3705 (NI91108.582, E1J16760.441)(NAD 83/91 COORDINATE VALUES) . 3. BENCH MARK IS KING COUNlY CONTROL POINT NUMBER 3871. WITH A NAVD88 ELEVATION OF 405.42. "'--... ,... " ' , -: \ '----, \ , \ , I\'A \ "~ 10" \ "'«~ :1-1\ , , , , , c?"C , , , , \ , , " " \\ I I , , , , , MAY CREEK DRAINAGE 1MPROVEM8IIT MANAGER: DOUG CHIN 9A1205 t.; King County Depar1rnent of NabJraJ Resoun:es and Parks No. Water and Land Resources Dtvislon CESlGNEI> UAU:. Nt..L::>VN ! I/LUII I :::.urw\:.1 No. ---Capital SerticeI Unft DESIGN ENTERED: M. 1VIIJ\:.l..1.A I '{LUll 1~~~~"1j~~ 4 Chri$tie TI1I8. DInJctor ElCJSIIIIQ ClONlI11ClNS. SlEET KEY, LEGEN>, OONSTR.ICI'ICN NOTeI CHECKED: NAYO 88 SHEET 4 OF 18 SHEETS # ~ ~~~, ~-::.. ---S,E,/oIAYVALlEYROAO ..... ~-~ ---, ----' ....... "-i f'-...... t; .... ~ " ====n'l :.' ~'" ':'<, ,"',' '~ [~~~~~~~~:~~C==1!!"U, . /XC" '~', 1 I I I ~ ---.... 0' '~::\\:\il\ :-::::-:"-'2:;::---.v,-.~! ________ '" _._ _ • .-"""n ~-~ 'fi:\,v_" -,O-YR. Ftro-o-_ ~"' ______ , .' .. 'V /' . 1"" , "'" / '_" ~ ~\, "S>'''", -,/ _ 'if, _,' \" b, ') '-',_ \ '\: ~\\-_ ... "'"" ',,, /' ~'LT ----'c. ~>~'~'! '\ ) \.'>",_ I NSTALL WEIG "AINTAJN coG .,,~~ ~~,: !I \ "'\ ~_ \, T AIN AND M ORARY ~ '" " "~ C2URFOOT WIDE TEN"EPL ALCOVE 'TO"."".!!' ~ , :".( ~ ,'< ~\. _" ...... ~ _ ~2' I I / ,- Y/J~" _ ~.,_/ I / \\ I Q'L / \\. -\..-- Y;H;n~E'( !I JEFFREY WAU<ER 15125 ::..t, t.1AY VAl.LEY RD I I I I I I, I, I 1 I, I: I I .' .' I ' " ~ -, " , .. ~'v, '" ""' CO ~ , ,-"""4, , -TREIw BUFFER /\ \ \.\ '" @ ~/ ,,-.,~ , , ,,' '", ~-/ D~),~ -I l ,/~/ '-------1 ~, WETLAND MITIGATION _",_,ARU-' -1\ OFF-CHANNEL", ALCOVES r. ' / \ ----~" ( 0 , , / . o o + ! ~,=--, ,. o o + --- lEse LEGEND t ' , , , '/ + + ~ + + + .. ~ ± t MXXX2J ilihlAARR&§§p ~iii[[[j,ITTH gtIITUlrXIITl "0 r";'tr! -- .... ---.. ·--r---.... ---\_·· WETLAND STAGING AREA DRYING AREA ACCESS ROAD CONSTRUCTlON ENTRANCE SiREAM ACCESS, APPROXlJ,I,A.TElY ~ 50 Fr:ET CONCRETE BAARIERS WITH PlASTlC UNER SANDBAG BARRIER OR EOUIVAlENT ______ -i@lBYPASSHOSEANDPUMP __ , _ _ _ PI.AN11NG/MmGA110N BUFfER A ;C A H A SD...T FENCE _ i _, I _ STREAN BUFFER WEiGHTED SILT fENCE/CURTAIN •••••••••• _ WETlAND BUFFER ---C&G---ct..£MING AND GRADING UNITS ---100 YR FlOODPl.AIN OF CONSTRUCnON. PLANT ALL AREAS WITH NATIVE VEGETATION PER ECOLOGIST. \ -- \ \ \\ CALL 2 WORKING DAYS \ BEFORE YOU DIG \ '"'YO .. 1-800-424-5555 \ (UNDERGROUND LmUTY l.OCI.TIOHS ARE APPROX.) /" PRo..ECT MANAGER: OOUG CHIN [7/2011 I KCFCZO No. ---------" DESIGNED: UALt. Nt.t.::iUN 17/2011 I SURVE'I' NO, _____ -I DESIGN ENTERED: >.WNTENAJNCE DIVISION No. \~ . -- \._--_.-----------.... -STREAM BYPASS SUMP. -PUMP. HOSES ANO ECOLOGY . _ ~ BLOCK/STEEL PLATE DAM TO BE E'QUIVAlENT. ________ ~ RELOCATED AS CONSTRUCTION PROCEEDS ,~( A \ ~-., -EXIs;nNG-f'AFfM FENCES Tn...... ____ _ ALONG CREEK. -, "'-.. TEMP,ORARILV RELOCATED AfTER CONSTRUCTION SILT FENCE ffi • - SOUTH SOIL ~~:,~\,,,.~ ~ ~~ -------------~ --~~'----' --------~-'-____ '\. TS(GE TSEGAY & KIDANE AYElE __ ______ ',--- \ ., ~,,~~V' "'" '\, ~ ~ 10(k'B 148TH "JE~~ \ -~ ,0,,' ~ // __________ -::: __ <'''._-':= :&t,',;/~:\?~>C.~/ :-~'-~/0~-. ~-----~~s W King County Department of NatunIJ Resoortes and Parb Water and Land Resources DIvision Stormwater Services SeaIon Capital Servicel Unit Christie True. Ditvctor ~ ----~~-------~ ----~ ~ MAY UiEEK DRAINAGE IMPROVEMENT 1BIPOfWI'( SIOSION /lK) SECIIENTAllON 00N1lI0L PLAN, LEOEI\I) SHEET 5 OF 18 SHEETS I I I I I I I I I I I I I I I I I I I , I \ \ II \ ~ .. < \ I -----' *\~' > r:I --. " ~ "f:lIl!a -, ,"""'" ".""." -, : CSSI \ I ' IiEIii9 " STREAM BUFFER \ ,1lEIII ,--', 1lIl!!IlII"IlIl!!IlII"'- " \ \ " \ '--'1/ \ > I x 'II \ Y , -~, I I \ i \ I I? .l.J) 1_ - \ 1.....-\"1 f ' \ \ ~ \ -'1'""1 --\ \ \ ~4111 iii '" CI '" '" CI), iii III eJ... IiICI CIS '" \ \ \ I I ., \\ I ~~ f /~ / CO /"/ ~ i \ NOTE: IMPACTS TO MATURE VEGETAn-ON WILL BE MINIMIZED OR AVOIDED TO THE MAXIMUM EXTENT POSSIBLE UNDER THE DIRECnON OF ECOLOGIST IN THE FIELD. NO MATURE TREES SHALL BE REMOVED. METHOD TO AVOID IMPACT: APPROXIMATELY EVERY 50 FEET. AT ONE SIDE. EXCAVATOR WILL ACCESS CREEK AT THE DIRECTION OF ENGINEER OR ECOLOGIST. SEE BELOW. \ "" '. \. \ \ ~ --.----.~.~ <2, \ \ I I ' \, I I ' \ I J " \ \ \ ~ I \ 'f. " r-REMOVE SEDIMENT 5+40 TO STA. 26+26 TYPICAL SECTION. SHEET I o 0 o "'ct o 0 0 + + + .~ ~ PLANTING MmGATI~ BUFFER :: ~ ______ ' _' __ 1 __ • __ '--, ..... - , \~ '.,-~-~_,_..J \\ ' . '--"~.,.,,,---, --""i'!!'!.._, -"1 -T~'-"W'" ,;;:.~ ........ ' -_'V ___ 'l/~~, ;),¢\ ~-~~~ -'-~;¥1*~ -'-.. ~ESHE ~C , , " , ----... -, LANE 15' ~ SPACED APPROX, 50' APART (TYPICAL), EXISTING VEGETATION BETWEEN 'LANES WILL NOT BE DISTURBED. ACCESS lANE WILL EXTEND FROM CREEK TO EDGE OF ACCESS POINTS WILL BE ~ ",<, X"'--'--IN FlELO BY , V' ENGINEER/ECOLOGIST TO AVOID ':-., DISTURBANCE TO MATURE TREES, OFF ~,._. __ -ROAD EQUIPMENT REQUIRED TO . -""INIMIZE SITE IMPACT TO INCLUDE TRACKED EXCAVATOR, OR EQUIVALENT AND TRACKED DUMP Tn ...... ~ ........... Af1£R -_' __ 1.- ...-...-. ...:=-------~ WIiJ . --,;--,,--'<~" --,-.--' -;--'- ,11'--'" .. CONJUNCTION WITH SEDIMENT. ALSO ~.d--'REMOVE VEGETATION OBSTRUCTING CHANNEL FLOW AND REED CANARY GRASS AT THE DIRECTION OF ECOLOGIST OR ENGINEER PER CROSS SECTION DErAIL SHEET 15 ALONG STATIONS 5+40 THROUGH STA 29+00. '., --------'-3, s-------- -, -- •••••••••••• ,.. ~"!'~~' .--------,-"/'/ ~~21r"----; ~ -----~-~. -------'-'--==-", ..... " \ , \ " \ ~--\ii, -. W-II: ,?, \ II , ,0 :\ _, ."~ "_,:,_.r,_,,, ·';_·ii_l'~-\.Y-. \ \ ~_//' \,j/' /'/'\ /~ "0,-,,,0 SUFFER ~ .... - l~;_\i_i' ===-------== . -/'- ~2~~ --,-----~ ~"c;.. ___ ----- ------- \. \ \ ~ ~~ \ ~ CALL 2 WORKING DAYS BEFORE YOU DIG '~ 1-800-424-5555 (UNDERG~~ L.OC'ATIONS AAE APPROx.) \ \ \ \ . \ \ 7+50 7+80 8+10 -201 -- 40 8+70 9+00 9+30 9+60 9+90 0+20 0+50 10+80 1+10 1+40 PROJECT WANAGER: DOUG CHIN 17 /2011 III.I".~I".LU No. PROJECT DESIGNED: UAL...t. NELSON DESIGN ENTERED: ![L.Oll MAINTENANCE DMSION No. 1+70 12+00 2+30 2+60 2+90 13+20 3+50 3+80 4+10 14+40 4+70 5+00 5+30 15+60 5+90 6+20 W King County Department of Natural Rosouroes and Parial Water and Land Resources Division stormwater 5eM'ce& Section CapItal ServIcn Untt ChmIie T roe, DirectIN MAY CHEEK DRAINAGE 1MPROVEMBfl" PLAN »D PROFLE STA &100 TO STA 18+20 315,0 SHEET 11 OF 18 SHEETS 1 1 1 1 1 1 I I" I' 1 I I I I I 1 1 I' 1 ) -~\.~ 1~1L-~..:-~~, __ -,~·~ / \ ) " REMOVE VEGETATlO¥'"OBSTRUCTING CHANNEL FLOW AND REED~Y GRASS AT THE DIRECTION OF ,ECOLOGIST OR ENGINEER PER VEGETATION REMOVAL CROSS SECTION DETAIL ON SHEET 15 JAND TABLE 2 ON mls SHEET. ~'i~JI,~,· NOTES: 1. SEDIMENT REMOVAL FROM $TA. 5+40 TO $lA. 26+26 2. STAGING AREA SHOWN ON SHEET 5 (S~GA"'" PROPERTY) ._' _",_ --.- ,--" -- \ ..,,- .:;;f--~ 1 - - IN STREAM'VEGETATION AT STATIONS LISTED IN TABLE 1 BELOW . AND PER VEGETATION REMOVAL CROSS \ SECTION DETAIL SHEET 1 5 ~ '\~ ... TABLE 1 Stationing of the In-Stream Willow Pruning for May Creek Station From Station To 0+00 0+30 0+70 1 +50 3+00 4+5Ci 4+90 5+40 "'" -0+90 -0+60 \ "\ TABLE 2 Stationing of the In Stream Reed Canary Grass RemOVal Station From Station To 0+30 0+70 1+50 3+00 4+50 4+90 26+26 29+00 /--r-----t-..-.,...,-: -_!-______ . __ L_-'--- < <"0 " <:? . ~ '. 0* TABLE 3 _ "~ Stationing of Sediment and Vegetation _______ . :> Removal -. ----------- -......... ~.... ' ,............... ---\ ....•.... } ) I~ :--:=.-, 1+50 1+80 2+10 PRO.£CT MANAGER: DOUG CHIN 17 /2011 I KCFCZD No. I PROJECT No. 9A 1205 • No. ______ -l DESIGNED: UAU. 1'Iu.;:>V1'I 1("LUll DESIGN ENTERED: MAINTENANCE DIVISION No. I STREAM tQ King County DeparIment 01 Natural Resources and Parks Water and Land Resow-ces Division StormwatBr ServIces Section capital ServIces Unit ChrlstitJ True, Dit8ctor \ (.ttt---EXISTING GUARDRAil \J i;~ (/''-- I." 1\ II A.' "m' ~STING GUYWIRE ,\ 1 n."'\\ " ) 148TH I BRIDGE 7+20 7+50 7+80 CALL 2 WOAKINCl DAYS BEFORE YOU DIG 1-800-424-5555 UTILITY LOCATIONS ARE 300.0 SHEET 10 MAY CFIEEK DRAINAGE IMPROVEMENT PlAN AK) PIIOFI.E STA 0100 TO STA 8+00 OF 18 SHEETS I I I • I I I' l I • I I' I I I I .' I • ",al'll 'i-'l-IC;\II'>G ~ INSTALL DRIVEWAY CULVERT IF THERE IS A ROADSIDE' DITCH PRESENT, PER KING COUNTY ROAD STANDARDS 4~-8~ QUARRY SPAlLS GEOTEXTILE UNDER SPALLS 12" MIN. THICKNESS PER KING COUNTY ROAD STANDARDS, DRIVEWAYS SHALL BE PAVED TO THE EDGE OF R-O-W PRIOR TO INSTAlLATION OF THE CONSTRUCTION ENTRANCE TO AVOID DAMAGING THE ROADWAY. IT IS RECOMMENDED THAT THE ENTRANCE BE CROWNED SO THAT RUNOFF DRAINS Off THE PAD. V MIN. ~ PROVIDE FULL WIDTH OF INGRESS/EGRESS AREA CONSTRUCTION ENTRANCE fB\ JOINTS IN FILTER FABRIC SHAlL BE SPUCED AT POSTS. USE STAPLES. WIRE RINGS. OR EQUIVALENT TO ATTACH FABRIC TO POSTS NOTE: FILTER fABRIC FENCES II II II NOT TO SCAlf SHALL BE INSTALLED I I I I 5,6 '--" 2"X2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC ........... ANCHOR FABRIC ALONG CONTOUR • 6' MAX. WHENEVER POSSIBLE U \. ~ 2"x4" WOOD POST SPACING MAY BE INCREASED STEEl FENCl FlElD BOOK: TO 8' IF WIRE BACKING IS USED REBAR, OR EQUIVALEN SILT FENCE NOT TO SCAlE 090561 01-20101 fE\ 5,6 '--" UNIVERSAL CONNEC---CTORS MARINE GRADE ALUMINUM b I II ) " ---BALLAST CHAI SILT CURTAIN NOT TO SCALE t: ~ N 7/2011 SURVE'Ym: KING COUNTY SURVEY BASE ~ING COUNTY ~ _ .~ KCFCZD No. PRMCT MANAGER: OOUG CHIN 1/ L, CHECKED: 02-2010 TREVOR CRAY, PLS I 02-2010 DALE NELSON 02-2010 - NO". BY I DATE PROJECT No. -._-" I SURVEY No. 7/2011 MAINTENANCE DIVISION No. DESIGNED: DALE NELSON 1/ £l DESIGN ENTERED: t.4. RADEllA ATION FLOTPo.IIVI'f ..i.. TENSION CABLE BELOW FLOTATION GROMMETS LACED TOGETHER WITH MANILA ROPE CONNEcnON '. 9A120S • \. \" CLEAR PlASTIC COVER '\ lEAVE EXISTING SOIL 24" ~I ~~;R;E~ill~~r,R;'N~~ SAND BAGS 0 80TH ENDS TO ANCHOR PLASTIC RESS \ H L 2'-0" 3'-0" 2'-0" 6'-0" MAY CREEK W 2'-0" 2'-0" / / / / Il).::!-t,-$';if) / &!.~'::;;;!/k. / -H -"7 ~I~ / ' ';.-~ / / \. EARTH BERM / (EXISTING SOIL) ~ SECTION TEMPORARY EROSION PLUG AT CHANNEL ALCOVE GRADING N15 rVISOUEEN OVERLAP AT JOINTS A MINIMUM OF 1 FOOT 3 / / METAL UFT 'I / __ / / ~ (D\ 5 '--" ~s:;~~~~gR~'N~G~J ~~.-"""~ /. / / /~-'/~./~/ f .4 • ;.. ~. 4 /' ..,-/ ~ --/,,' 6~~ MIN. DRAIN ROCK T ", '." '~.' '. ;4; 6..4 --'/.' / ---/ /" -----. -BACKFILL AROUND 6" ':.: '.<4'." :--4'.-< -.. :.:. • • _', / . / DRYING SOIL---Y -~ PERFORATED PIPE WITH ...,' • ': .,. , '. I -/ / -' / FILTER FABRIC WRAPPED H • -<. •. • •• ': ..... " 4 HIGH " ' '~" -,.,,"'-ALL SIDES DRAIN TO SUMP I . .'4>..,: ~-:" .... :':;: . '.,: I _~·".·,,<.,~.-.. ~~' •.. :.'~.I"" '.,-'/,._ / /.----"///./"(40 MIL 'VISQUEEN L \ L -.. " I ," ---/ ,/ CON~G~E AND GRk; BLOC~ - -i:;~~'0'0~~J&~~~/~~/~ ~ / /'-/ /'-/ /, / /, / /, / /'-/ /'-/ /'-/ /, / -", /" / /" /'" /, SOIL DRYING CONTAINMENT IF 5,6 NOT TO SCAlE '--'" tQ King County Department of Natural Resourca and Par1aI Water and Land Resources Division Stormwater Services Section Capital Services Unit Chri:stie True, DitfJctrx MAY UiEEK DRAINAGE IMPROVBAENT 1BII'alARY EROEIION N>D SEDlENT CONTRJL DETAI.S ,( SHEET 9 OF 18 SHEETS 2006-16 ,------------------------------------- /-------" \ I \ I \ I -----/ I I I / I \ \ / / / ( --~ / /; ') II - )1 I Jf .-'/'/ / / / / ( / I / 8 ...... CID~ :J:: I~O ..... W Vl ill I I I I I, I I I I:, I I I I! I, I I' I .' I -_ ........ _-.. ,-"" 8.~ 4f-4y ; .... ; .... ; .... ; .... ~ ;; .... V-4{{~ I?O-4D (UNOERGROUND um.ITY LOCATlOt6 ARE APPROX,) . . ; .. .. \ # '-" .... .. \ ;" .... \,' /I .... #\ / '" '-.... ...... l \ --"-~ l 4rp"410" ;' \ .--"'1. :---/" "-" '-... ...... . ';'. ~, '-","".,/\ : 'i ~. "". "%,. t ---\"'"NEY" i;::":'"LE' 001 \' i\~' L ~ .~ ''''''' 15'25 S, ~/,' \ ~IV~ <..<J/..y .. , ; , , " . I '. • \ ' l /... \ ! i' ,~\ ~ --• 'I" ~ \'.--~ ,t-,./-.......... 11/ '\\ '~'.~'-~ ~.IV)~" \\ I / ' " .-)~.,...-, ---' --'. 1\ , \' , '. \) , \' \. \ . . . .; --'-?" '. ~ ., .. ' .•... " y , " ". _. ---,,'" / " ~. ".' ", \" , ; ':7---': ,~''''''"" .• " . ,4/ \) "i., .... , '. \ f!' "')' \ «-ill ;--, .... .:~ L /" /~\ /"'" \'\.... _ .... " 'J .. t'/ ••• .,.,., . '.' II , " ",.., '0. • "~, ~' ,\ j i ,,"', \ \:' ""~, _ \\" ~"". \ \, #/" '. , ,I' -• , .". '" ~ 0' '~ .... t;:,". -ill ~,~, ~""-'~~. '"","', . '. '. "'~ ""''''-'''''' ~~; "" )/ c " ~''''-_" •• , "" ~ '" , 'I'''"",-~ "' .•. "" ~ .~' y_ '", =,~-.,."""" .... ;;,;" ....~ ", { .... '~ , STREAM r 1~~~~~~~~~(H~_"~ __ ' " ,. ,~ " "', ";' ....... , '\ '\ \ I<-~ ~~h, ~FFER (1.5')/ ' '-'''' ,. \ BYPASS HOSES AND BLOCK/STEEL PLATE DAM TO BE "'-'" RELOCATED AS CONSTRUCTION PROCEEDS ALO~~.CR~EK _~ ____ . • _______ ~~' ~' ,-/ ~~-.-'---=\\--..-. -----~-"""""'-:.. ~. ' ........ -----_. 81".LJINDER s ... RA$PHA.l BUITAR 9846 1"'8T,; AvE SE SOlfTH -" : sr~, \ ''''~<R\ ~"~ REtAO""l. PROJEC 1 '" .~, -~ <'----~'- ~~ '" ~~ , ~IV ____ '-'-"-";;;:'. --..... ";;--- "'" "'--- ;:;~~;;;;;;;;===-;:; ----~ ~, -~,\ --===:::--... " \ ,~ AnD """':~'~~~~D9jO!5!.10!';-!2!D~'Dti~;i~il~!ii~~it!lAPPRO'vfD: DON ALTHAUSER P.E. 7/2011 SURllE'fEO KING COUNTY 01-2010 PRO..ECT DOUG CHIN . KCFCZO No. IoIANAGER: 7/2011 SURVEY ~ ~ING COUNTY 02-2010 ~ PROJECT No. 9A1205 TREVOR CRAY, PLS 02-2010 2!: DESIGNED: DALE NELSON 7/2011 SURVEY No. ---------/ CHECKED; 0A1..E NElSON 02-2010 NULl N .... ~.. DESlQII omREO; M. RADELlA 7/2011 ~~T5~~~ "-, ----IV ________ W King County Department of Natural Rosourc:es BOd Partes Water and Land Resources Division stormwater Services SectIon capital ServIceS Un" ChristIe True, DiIector ....... --....... MAY UiEb< DRAINAGE 1MPROVEM8IIT 'IBoFORARY BIOSION AN) SBlIENTAllON CONTROL PLAN MER10L6.N W.S.LG.N.Z. NAD 83/91 NAYO 88 SHEET . 6 OF 18 SHEETS TEMPORARY EROSION AND SEDIMENT CONTROL NOTES: 1. THE IMPLEMENTATION OF THESE ESC PlANS AND THE CONSTRUCTION, MAINTENANCE. REPLACEMENT. AND UPGRADING OF THESE ESC FACILiTIES IS THE RESPONSIBllllY OF THE CERTIFIED EROSION SEDIMENT CONTROL LEAD (CESCL) UNTIL AlL CONSTRUCTION IS APPROVED. 2. THE BOUNDARIES OF THE CLEARING LIMITS SHOWN ON THIS PLAN SHALL BE CLEARLY FLAGGED BY SURVEY TAPE OR FENCING. WHERE DmRMINED NECESSARY BY ECOLOGIST, PRIOR TO CONSTRUCTION (2009 SWDM APPENDIX D). DURING THE CONSTRUCTION PERIOD, NO DISTURBANCE BEYOND THE CLEARING LIMITS SHALl BE PERMlTIED. THE CLEARING LIMITS SHALL BE MAINTAINED BY THE CERTIFIED EROSION SEDIMENT CONTROL LEAD FOR THE DURATION OF CONSTRUCTION. 3. THE ESC FACIUTIES SHOWN ON THIS PlAN MUST BE CONSTRuCTED PRIOR TO OR IN CONJUNCTION WITH AlL ClEARING AND GRADING TO ENSURE THAT THE TRANSPORT OF SEDIMENT TO SURFACE WATERS. DRAINAGE SYSTEMS AND ADJACENT PROPERTIES IS MINIMIZED. 4. THE ESC FACILiTIES SHOWN ON THIS PlAN ARE THE MINIMUM REQUIREMENTS FOR ANTICIPATED SITE CONDmONS. DURING THE CONSTRUCTION PERIOD. THESE ESC FACILITIES SHALL BE UPGRADED AS NEEDED FOR UNEXPECTED STORM EVENTS AND MODIFIED TO ACCOUNT FOR CHANGING SITE CONDITION (e.g. ADDmONAL COVER MEASURES. ADDITIONAL SUMP PUMPS. RELOCATION OF DITCHES AND SILT FENCES, PERIMETER PROTECTION, ETC.)' AS DIRECTED BY THE PROJECT ENGINEER/ECOLOGIST. S. THE ESC FACILITIES SHALL BE INSPECTED DAILY BY THE CERTIFIED EROSION SEDIMENT CONTROL lEAD AND MAINTAINED TO ENSURE CONTINUED PROPER FUNCTIONING. WRmEN RECORDS SHALl BE KEPT OF DAlLY REVIEWS OF THE ESC FACIUTIES. 6. WHERE APPROPRIATE, AREAS OF EXPOSED SOILS. INCLUDING EQUIPMENT ROUTES. THAT WILL NOT BE DISTURBED FOR TWO CONSECUTIVE DAYS OURING THE WET SEASON OR SEVEN DAYS DURING THE DRY SEASON SHALL BE IMMEDIATELY STABIUZED WITH THE APPROVED ESC METHODS (e.g., SEEDING. MULCHING. PLASTIC COVERING. ETC.) 7. TEMPORARY PATHS USED FOR EQUIPMENT ACCESS WILL BE RESTORED TO ORIGINAL CONDITIONS ONCE CONSTRUCTION IS COMPLETED USING THE APPROPRIATE UPlAND OR WETlAND SEED MIX (SHEET 18). ONLY TRACK VEHIClES OR APPROVED EQUIPMENT ARE ALLOWED BEYOND ACCESS. LANDINGS AND STAGING AREAS. B. ISOLATE MAY CREEK FROM CONSTRUCTION AREA BY USING COFFER DAM, AS DETERMINED FROM SITE CONDITIONS DURING CHANNEL EXCAVATION. INSTAlL A ClEAN SUMP UPSlREAM OF COFFER DAM AND PUMP FROM SUMP TO SUITABLE LOCATION AS DETERMINED BY ENGINEER OR ECOLOGIST. 9. SECONDARY PUMP WIU BE USED IF EXCESSIVE GROUNDWATER IS ENCOUNTERED DURING CONSTRUCTION. SECONDARY PUMP WILL BE ON SITE AT ALL TIMES. 10. PUMP SYSTEM/SETUP TO BE FIELD ADJUSTED AS NEEDED AND DIRECTED BY PROJECT ENGINEER/ECOLOGIST. 11. REINTRODUCE STREAM FLOW TO THE EXCAVATED CHANNEL SLOWLY. DO NOT REINTRODUCE FLOW INTO THE EXISTING STREAM UNTIL THE FLOW MEETS STATE WATER QUALfTY STANDARDS. PUMP TURBID WATER TO THE DESIGNATED VEGErATED UPlAND AREA OR A BAKER TANK. . 12. MOVE PUMP SYSTEM/SETUP DOWNSTREAM AS CONSTRUCTION PROCEEDS AND AS DIRECTED BY PROJECT ENGINEER/ECOLOGIST. 13. MONITOR MAY CREEK UPSTREAM AND DOWNSTREAM OF THE CONSTRUCTION AREA TO MAKE SURE THAT STATE WATER QUALIlY STANDARDS ARE MET AT AlL TIMES DURING CONSTRUCTION ACTMlY. IF WATER QUAI.JTY THRESHOLDS ARE EXCEEDED STOP CONSTRUCTION ACTMlY AND MODIFY BMP'S TO BECOME COMPlIANT AS DIRECTED BY PROJECT ENGINEER/ECOLOGIST. 14. PRESERVE EXISTING NATIVE VEGETATlON IN CLEARING AREA UNDER DIRECTION OF ECOLOGIST. .~ WELL VEGETATED UPLAND MEA PUMP -SUMP (AS NEEDED) PERF' PIPE o ." ECOLOGY BLOCKS ~91L -~:~Y~N~:iR~~. .0 .. · ... ~ .. · •• 0 GRADE SUMP AS DIRECTED BY THE ENGINEER OR CESCl AS NEEDED. CESCL SHALL INSPECT SUMP DAILY TO DETERMINE IF SOIL IS SATURATED. IF SOIL IS SATURATED PUMP EXCESS WATER TO TURBID WATER DISPOSAL AREA PUMP WILL BE ON SITE AT ALL TIMES. IF TURBID WATER DISPOSAL AREA BECOMES SATURATED PUMP TURBID WATER TO BAKER TANK. SOIL DRYING SUMP DETAIL NTS SECONDARY PUMP ON STANDBY TOP OF BANK TO STABLE CHANNEL ..... 200. PRIMARY (DOWNSTREAM) PUMP -.,j -.\T ! r -y--'T-_ . I .now WASHED GRAVEL --1!8~,t: 1 M -1f' ROUND PERFORATED 24 ~ ~ PIPE/RISER ALL MATERIALS SHALL BE REMOVED WHEN MOVING TEMPORARY CHANNEL BYPASS PROFI! E ->I PLAN AND PROFILE VIEWS TEMPORARY CHANNEL BYPASS DOWNSTREAM COFFER DAM " AND PUMP. SEE NOTE 11 24 ~ RISER THIS SHEET. . .r-UPSTREAM COFFER DAM ,/ .~ ~... rONSTRUCTION ~ " I<RfJo. ~ -FLOW PUMP '--i.~ PUMP ON STANDBY ~ FOR WET CONDITIONS) 'W . . 4-PRIMARY PUMP DISCHARGE TO (6-PUMP ON STABLE CHANNEL, STANDBY FOR WET BEYOND ACTIVE PLAN CONDITIONS) WORK AREA -- (DOWNSTREAM) PUMP, DAM MoLD PIPE DETAIL (TYe.) fA\ NOT TO SCAL..£ 5.6 '---" .. , .... SHEET 7/2011 09056 01-2010 APPRO...m: DON ALTHAUSER, P.E. U1 King County MAY CREEK DRAINAGE IMPROVEMENT FIELD BOOK: SURVEYED: KING COUNTY 01-2010 PRQ.ECT DOUG CHIN MANAGER: SURVEY BASE ~ING COUNTY 02-2010 TREVOR CRAY, PLS 02 2010 DESIGNED: DALE NELSON CHECKED: DAlE NELSON 0'-'01 -DESIGN ENTERED: M. RADaLA ""'SIOII NUM. BY "'TE KCFCZD No. 7/2011 PROJECT No. 9A1205 7/2011 SURVEY No. 7/2011 MAINTENANCE DMSION No. • Department of Narural Resources and P8I"Q Water and Land Resources Division Stormwater Services SectIon Capital ServIces Unit Chri$Iie T roe, DinJclor 'I'ENI'ORARY B\OeION NoD SEDlENTA110N NOTES NoD OETALS 8 OF 18 SHEETS 2006-16 I I I I I I I I I I I I I I I I I I I -~ > '------", '\ x_ --eX ;-IMPACTS TO MATURE VEGETATION WILL BE MINIMIZED ! . OR AVOIDED TO THE MAXIMUM EXTENT POSSIBLE ! ~ER THE DIRECTION OF ECOLOGIST IN THE FIELD. NO MATURE TREES SHALL BE REMOVED. METHOD TtN.VOIO IMPACT: APPROXIMATELY EVERY 50 FEET. AT '\lNE SIDE. EXCAVATOR WILL ACCESS CREEK AT THE DIRECTION OF ENGINEER OR ECOLOGIST. SEE SHEET 11. " .~-~".~-)( - i I r-___ ___ / ................... -- I ---I / L.. I / /' ------I / -'" ----.......... / // /.? ----.Jv -' iT 'r II ' II .s:~ ·"tql'k ~«~ <\'0,,<> / II II /1& Sl; 1/ &UrF; //c.u, / I II £:// (/65) ~ /1 .... , ~--...-\V. ·_'--x---.x -....,......... -.:::::----....... . " ------------'~ -...-... '" " ;r."O-...... ._,. -"'lIlaaiir 'lIlaaiir,' ....... , . lIlaaiir, ..... FlB..D EIQOK; 50"""'" " "" IN CONJUNCTION WITH SEDIMENT, AlSO REMOVE VEGETATION OBSTRUCTING CHANNEL FLOW AND REED CANARY GRASS AT THE DIRECTION OF ECOLOGIST OR ENGINEER PER CROSS SECTION DETAIL SHEET 15 ALONG STATIONS 5+40 THROUGH STA 26+26. "lIlaaiir ........ ~r~~UFit:""" ..... ,' <~J o o ... ... '" REMOVE SEDIMENT STA. 5+40 TO STA. 25+26 SEE lYPlCAl SECTION. SHEET 15 .... ~ --' ........ --y --, ------·x _ ..... ,~..:..~ F-X '.--. -I ... / C "'{+ ~ + ~ -----x __ )( _ -........... - ~ II) -5' NOTE: 1. STAGING AREA SHOWN ON SHEET 5, (SEGAY PROPERTY) " ""'" .... ,,, ..... ,. , ", " " i i 41/ _.9:-" >.: :$:-, j I , £ -. ~ ~~~., . ~--"':--" ---........~ REMOVE VEGETATIoN AND REED ~-X _____ .. GRASS OBSTRUCTING-CHANNEL ALONG STA \ --......... x_-......---.J v 26+26 THROUGH ST029+00 \ ' ~.I -- .- /1 ~II . I II / II / I /1 &Ur%r//c.u, £:// (/65) .,..- ';l,.:~1!r ____ ~x ___ x ___ I 1::., x ____ :.:-_ .>J 23+70 24+00 4+30 4+60 4+90 25+20 5+50 5+80 6+10 26+40 6+70 27+00 7+30 27+60 7+90 28+20 8+50 28+80 29+10 9+40 9+ 70 30+00 0+30 0+60 0+90 31+20 1+50 1+80 32+10 32+40 090561 01 20101 I ~rfL r$-"i?r1\h I APPRO\o£D: UUN ALIHAU::>t.t<, !-'.t.. 7 2011 KING COUNTY 01 2010 KCFCZD No. =~; DOUG CHIN 7 2011 PROJECT No. DESIGN'" UALt. Nt.l.:>UN ! I/~Ull I SURVEY No. DESIGN ENTERED; M. KAUt.LLA . MAINTENANCE ! I nUll I DIVISION No. W King County 9A1205 Department of Natural Rasourt:es and ParKs Water and Land Resources Division stormwatar ServIceS SectIon capital s.mces Unit • C/Iti3tJfJ True, Dit8ctOr CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 MAY CREEK DRAINAGE IMPROVEMENT SHEET 13 OF 18 PLAN NC PROFI..E SHEETS STA 24+00 10 STA 29tOO I I I I I I I I I I I I I I I I I I I SCAlE IN FEET /~/ ... >~ / CCC WETlAND BUFFER -rW ~-' pC'c-=~~~~~:=§i~~~ --...,-~. -... '. ···.-oI~ NOTE: LOG PLACEMENT TO BE DIRECTED IN THE FIELD BY THE ENGINEER/ECOLOGIST. SEE LOG TABLE AND MmGAnON CONSTRUCTION-NOTES SHEET 17. LOG LOCATIONS SHOWN ON THIS SHEET ARVtONCEPTUAL ONLY. ~ " " / ~ /: /,,/\/ -\.:~~~ " ./ ..4- , 't~'/ , -, -~ , J -~. ", t:... \ ~- ~ ;t. .~>" ".~ ~, "'\ ' . -""',.--~_ : . J/.' ,. ~ ~ y~ "0../ -, ,-"'" \, \., :-. / ''''Q "'- APPLY PROPEX 841 8 OR . EQUIVALENT AS DESCRIBED SHEET 17, NOTES (8) 4. PlANT WITH WETlAND ENHANCEMENT VEGETATION FROM TABLE ON SHEET 18. " ~ ~4P ~ -<; j'" ~"-.-._-,.."' " oS' "-I "-.~~ "-I "-'f)-" "-I "-,"-" "-" ~ >-\. 0..,,, I "- \/ I "-" \ "- \ "-,,- \ ;~ ? "- CALl. 2 WOFlKING DAYS BEFORE YOU DIG 1-800-424-5555 (UNDERGROUND UTIUTY LOCATIONS ARE APPROx.) MERIDIAN W.S.LG.N.Z. NAD 83/91 "-"-"- NAVD 88 --..... .~ "- "-"-"- "--", ............ .~ "-"- ~"-"- "" ......... ~3JJ,> ('-~/ i: : , ! t:::::::J I -.i /' , , J1) "~ " '.~, "~ ~~ ....... .'\~. '" -. . ',~ -~-:-~ '--;~:: _'-. ___ I ~>, \~ --.,:: -:..:0:",.' EAM lltIfl'ER (100'~ \~ -~ , ~ .... ~0 O.~/~~~T~IN]G~P~O~S~TgSI .... / ~ / / .... .... INSTAll. 3-STRAND BARBED-WIRE ~NCE WITH T -POSTS. TO BE fiELD ADJUSTED AS OIRECTEO TO JCH MmGATION AREA. ..... W£rL4tvo ..... ::e ~~~: DOUG CHIN 7/2011 KCFCZO No. PROJECT No. 9A 1205 DESIGNED: DALE NELSON 7/2011 SURVEY No. --------1 DESIGN ENTERED: MAINTENANCE DIVISION No. -." IEXIS .-, ' .... ""')..;: .. ,. _-.co ';':,~::;.:.. --'~ -~ -- tQ King County Department of Natural Resources and ParU Water and Land Resources Division Stormwater Services Section capital ServIces Unit Christie True, Dit8cIor MAY CREU< DRAINAGE IMPROVEMENT WE11.AN) NoD II"AAAN 1oIl1QA1ION BrA. 0f(J0 -BrA 7iOO .§' c? SHEET 14 OF 18 SHEETS I I I I I I I I I I I I I I I I I I I L """, .. ";,~ ~" ~; "'" I '%"'-'" :.:" '-"\,1-" '" ................ ,'11 r---.---- SCALE: A: ,/.',,- += ,! • __ .• ",m."_"m"., ... ,.""=:L,,,,.,., m, •• ,.,.",.31~,oL J ........ 315,0. J m •• "4.".,. "ANti"t-'·· NCHE' ~I~'[,"I • :.s:::::i .... :=J ... ?i?S':O-' '-"'-'] ?i1:O;.O /) Iv," . ,nPicALbHWMfRdMSTAO),OO I BEGIN .¢OVE' 1 FboT ABove mmNG I '"n nn TO ?+09 ELPATI?N 3~ 1.7' h. '\i-CHA/<NEL!. BOrt.O,q.EC·jijii:SI. AT l}jIS I GFWlE!'l. COVE 5,~.'" (1801) STREAMBED GRAVEL FOR ALCOVE APPLICATION: . . 'I " '\ TYPIGAl SECTION) i , I i to CATCH EXISTING us sm. SIEV'E SIZE . . ' . , . '('l"CUUNU ~t't<LI'lI'\.. 1 U:) , . • ; , ; J~,:':::,"":+~',:~I:~LOf~~~# -/:-~~j-:/~ %', ~' . '/'Y. .'/.~).,.:-.::, ~:.:. /._' >!:y).: >'j .;/_y~ I ...... ..1 .l .. .1.. .. .1 .... ..1 ........ ; ....... t:01:. ;'5' WIDE (INLAi<D) . "hrALl JlITE MATnNG' 8EY(>ND . l : :: i-1f-~-tG~~]- 40,00 60iOO I 70iOO 80iOO I 90iOO i 100.00 1110.00 12, ---, TYPICAL SECTION OHWM NOTE: HABITAT MITIGATION ALCOVE GRADING STATIONS 2+33 TO 3+04 AND 5+09 TO 5+53 OLSON. P. AND E. STOCKDAI..£. 2010. DETERMINING THE ORDINARY HIGH WATER MARK ON STREAMS IN WASHINGTON STATE. SECOND REVIEW DRAfT. WASHINGTON STATE DEPARTMENT OF ECOLOGY, SHORELANDS 7 ENVIRONMENTAL ASSISTANCE PROGRAM. LACEY, WA. ECOLOGY PUBLICATION #08-08-001. FlElD STAKED BY KING COUNTY ENGINEER III. ENVIRONMENTAL UNIT MARCH 2011. SCALE: H: 1--10', V: 1"=10' ..... REiD BOOK: 09056 SlJFNEYED: KING COUNlY SURVEY B.\S[ ~ING COUNlY TREVOR CRAY, PLS I 02-2010 a-IECKED: _ DAlE NELSON I HUM. idsOH l.vl DATE PRO.ECT MAN"GER: DOUG CHIN 7 2011 7/2011 0ESIGNfD; DAI...E NELSON KCFCZDNO'~ 17~2011 I ::~\~O 9A1205 0ES1Q.1 ENTERED: M. RADEllA 7 2011 MAiNTENAN'CE DIVISION No. • 6 INCHES 4 INCHES 1 1/2 INCH 3/4 INCH 3/8 INCH NO.4- NO. 40 NO. 200 PERCENT PASSING AX WEIGHT 70-80 55-70 45-60 .30-50 25-.35 16-.30 15-20 0-5 COBBLES MAY BE INCLUDED IN THE GRAVEL AND ALL COBBLES lARGER THAN 4-INCHES IN DIAMETER SHALL BE EXCLUDED FROM THE GRADATION TEST. GRAVEL AND COBBLES SHAlL BE ROUNDED. CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 unUTY I..OC\TlONS ARE .\PPROX.) U1 King County . Department of Natural Resources and Parks Water and Land Resources Dlvtsion Stormwatar ServIces SectIon _-- ChristIe True, DJnK:tor MAY CREEK DRAINAGE IMPROVEMENT CRC SS !EC lIONS AN) HAllTAT 1.ITIQA11ON DETALS SHEET 15 OF 18 SHEETS ."" "1'0 ~ ~~STALLAT!QN NoTES' .... y ............. " ............. ' ............... , ...... ~ ......... -••• , ..... , ...... " ...... ..:.QI-" .. <iF LWP, • I • I • I . I .1 ._MANTRA LRAY...;MR~J.NCHO . . . IT OF 50 PERCENl SURFACE AREA OF II leV ,::nl Dt"k't-t"1\IT !Q~ . ..I:¥?~ Lf.~~~ .... "':)f*f/:~A?7'-'" k ' i ' 1 ' I AlCOVE GRADING ~-, E. ISTING Gf'!OUNq : : I: : 7'\j .. ·· ~-~."7:.:,..,.-<1::'<. ~\I t MAyJ ..... /~'/l~\Y>1»S»~y;~7v " • .fR/EEK ",.\'\10"/ /1 . /:V/l:,(/.,,\.v,-q::;;.~(:<h.«J:. V-v(.I',..:: A,f' , I , I,/\")j,,,,/,'{/,,-/ /"",' ····r········I···I".t..~\1vt.··:t-""'\:I"··~Mct.ptJl:.uJ·······:l······· : LLI 30 ,FO0l11' LO~ t.11~. 1 2, 08'1. , 1 : jy.ANtJ.-I.QI=<' ~'---S.HOW.l'a.l .. nN:"'.nrr.4.l1 ~_C;:HFIT-1_7 t.,n nn '7'1'1'1'1 : r 'T'"L9G I I . _ ..... , ... ;c' .. ·:::;:C-CI" -_I~ .' y ,,<,/0:)A ',y-:>::' '~}»1;y}"y,,"0I';~\Y~' ,\Z7J'~lO nn : / r )~Y'i /:>.. ,ur/I'\",/)(V/."f /'l"r~~ , i"--..: :!: : 1\. :/11'/': "inn nn N'\I'lrT'\lI'~lr" ~JYPI~ M~nJ:"V I ~ ,. _ ............. . LOCATIONS: 40,00 ! 30,00 I 20,00 I 10.J)0 I' "".' , 10l)0 I 20,00 I 30,00 1 40,00 1 50,00 I 60,00 1 70,00 1 80mO i 90,00 1 100.001 11 0:00 . I . I TYPICAL SECTION -HABITAT MITIGATION LOG PLACEMENT HABITAT FLOODPLAIN AREA AND ALCOVE STATIONS 2+33 TO 3+04 AND 5+09 TO 5+53 SCALE: H: '"-10', V: 1"-10' APPROVED DON ALTHAUSER P.E. 09056 FIElD BOOK' I'RO.£CT WANAGER: DOUG CHIN I SUR'vnED: KING COUNTY SURVEY 8'S£ ~ING COUNTY r 02-201C ! CRAY, PLS' "'.1-~ DAlE NELSON - 1"""·1 f1( DESIGN ENTERtD: M. RADELLA "'IT I CHECKED: • DAlE NFl SON ............ ~ ... I ::=-·~::f-~~=:=~·]=~·-·=,,-:~·:~:\.JI., -"-_ .. _·_·_·'--'&1 EROSION CONTROL CLOTH ~ I EROSION' SEDIMENT -=-1 --= -." :::.::=--=-_~_ ._ . . '-...: __ __ __ /'c" ~/» V>:,'" ~' ,--_ _ I ____ >:___ ,-' ~'/)J/; >j"-;;/ A A " \~«::;-0 =--------"_, ~O "7;~ "l';-.-oWrn'ro ' " -Y:l\r~~%'" ~~~~(~2~~~i~~( s~L~g~O'STsg}f5~~r~~~' '#~~~/T(<< V //, /, /",» <,,,V"C,v,,-,,(O±OO-29) AllONS -,,,/(~'V/'7)Y .-_"" ::v-::v-V _ " A' A' =~ ~ ~-~2 % -,-' ""''''' 'iPI/oi""----- _ '-' ", ,,( V ~"".,~ ",< " "m ''" -/ / / / / ," "I' , EQUIVALE' JID "V"Y'OOO "', -~. ~. . i' ,00' CLOTH, &OE fROSION 20'00 ±OlLIO M STA. 'V? 7/2011 KCFCZO No. 7/2011 PROJECT No. 9A120~ 7/2011 SURVEY No. 7/2011 MAINTENANCE DIVISION No. 4 . _~~o~n __ _ 30.00 TYPICAL SECTION FABRIC APPLICATION SCALE: H: 1· ;: 2.5'; V: 1· =2.5' UI King County Department of Natural Resoun::es and P8Ib Water and Land Resoun:es DivIsion stormwater SeNIcea 5edion C8pItaJ SeIYIces Unit ChrlstJs True, Director CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 (UNDERGROUND UTlUTY lOCATIONS ARE /lPPROX.) MAY CREEK DRAINAGE IMPROVEMENT SHEET 16 CRO 99 SEC'llONS AN> HABITAT 1ITlClA11ON DETAlS OF 18 SHEETS -10 I I I I I I I I I I I I I I I I I I I 3/4" NON-GAlVlNIZED CHAJN FINISH GRADE PROVIDE MANTA RAY MR-l ANCHOR PER LOG WITH 5/16" DIA. STAINLESS STEEL CABLE FROM ANCHOR TO CHAIN ATTACHMENT EYE AT EXISTING GRADE. CONNECT WITH lOK-A-LOY 10 CONNECTING UNK OR EQUIVAlENT. SECTION LOGS WITH 5/B" DIAM. REBAR CUT FLUSH TO LOG MIN. DEPTH BELOW FINISH GRADE. ACQUIRE 6' EMBEDMENT IN CONSOUOATED SOIL LAYER. TEST HOLDING CAPACIlY PER MANTA'RAY VENDOR SPECIFICATIONS. # of LOGS 7 5 4 16 total 30 30 60 total 2 78 total LOG TABLE LOG ROOTWAD OR LOG SIZE LENGTH WITHOUT (W/OUT) ALCOVE AREAS 18"-24" dbh 30' rootwads 16"-18~ dbh 30' rootwads 12"-18~ dbh 30' rootwads FLOODPLAIN ROUGHN ESS 12"-14"dbh 30' w/out 12"-lB"dbh 30' rootwods 27'min snags LOG WITH ANCHORS fJ\ tognde FlEl.D BOOK: SURVEYED: i ~ :t:1;i • ~ ? g 09056 KING COUNTY StJIM:f BASE ~ING COUNTY TREVOR CRAY, PLS CHECKED: DAlE NELSON SNAG DETAIL N15 01 2010 01 2010 02 2010 02 2010 02-2010 NlAI. N15 ~ -RE'ASION fR'\ BY 13 '---" DATE 13 '---" Attach sign to post __ 5/16 galvanized lag bolts with .ashers +--8' .4x4 c .... or .................. WETLAND PROTECTION SIGNAGE N15 SNAG NOTES: 1. WILDUFE SNAG TO BE PLACED N5 DIRECTED BY ENGINEER OR ECOLOGIST. 2. AlL SNAGS SHALL BE WESTERN RED CEDAR OR DOUGlAS-FIR TREES WITH A SUBSTANTIAl PORTION OF THEIR UMBS LEFT INTACT. DO NOT TRIM TOPS, AS DAMAGED OR BROKEN TOPS ARE PREFERRED. PROVIDE lOGS WITH NUMEROUS UNTRIMMED UMBS, WITH A MINIMUM OF 6 UMBS. lOGS USED FOR SNAGS MAY BE PARTIAllY HOLLOW AND CONTAIN CAvmES /!S LONG AS THEY ARE GENERALLY SOUND AND INTACT. 3. SNAGS SHALL BE A MINIMUM OF 10 INCHES IN DIAMETER AT BREAST HEIGHT (DBH) WHEN INSTALLED AND SHAlL BE PLACED INTO THE GROUND TO A DEPTH EQUAl TO 1/3 OF TREE HEIGHT BELOW GROUND. 4. SNAGS WITH SUBSTANTIAL ROOT MASSES ATIACHED MAY BE PLACED TO THE DEPTH INDICATED AND BACKFILLED WITH QUARRY SPALLS AND SOIL ONLY UPON APPROVAl BY THE ENGINEER. APPRO'l[[): DON AlTHAUSER, P .E. 7/2011 PRO.£CT DOUG CHIN 7/2011 KCFCZO No. ~ANAGER: PROJECT No. 9A1205 DESIGNED: DALE NELSON 7/2011 SURVEY No. DESIGN ENTERED: M. RADEllA 7/2011 Ml'JNTENANCE DIVISION No. 4 r- MmGA]QN PLAN NOTES <Al CONSTRUCTION NOTES 1. TREES TO BE PRESERVED WILL BE FLAGGED IN THE FIELD BY THE ECOLOGIST. 2. INSTALL SILT FENCES WHERE DESIGNATED ON THE PlANS. INSTALL ANY OTHER EROSION AND SEDIMENT CONTROL MEASURES AS REQUESTED BY THE ENGINEER 3. ELEVATION SHOWN ARE FINAL GRADE, 4 TO 6 INCHES OF OVER-X WILL OCCUR AND BE BACKFILLED FILLED WITH STREAMBED GRAVELS OR COMPOST WHERE INDICATED ON PlANS. 4. EXCAVATION OF ALCOVES ADJACENT TO THE STREAM CHANNEL SHALL TAKE PLACE ONLY DURING THE FISH WINDOWS AS DESIGNATED IN THE PERMITS. WHEN EXCAVATING ADJACENT THE STREAM CHANNEL AN EARTH PLUG SHALL BE LEFT BETWEEN THE EXISTING STREAM CHANNEL AND THE EXCAVATION AREA. PRIOR TO REMOVING THE EARTH PLUG AND CONNECTING THE EXCAVATED CHANNEL, A TURBIDITY CURTAIN SHALL BE INSTALLED AS SHOWN IN THE DETAILS TO PROTECT THE STREAM FROM SEDIMENT AND TURBIDITY DURING CONNECTION. 5. IF /JJf( GROUNDWATER IS ENCOUNTERED DURING" EXCAVATION, DEWATER BY PUMPING AND BROADCASTING TURBID WATER THROUGH SILT FENCE AND DISSIPATED OVER VEGETATED STRIP IN UPlAND AREAS OF THE SITE. IF GROUND BECOMES SATURATED A BAKER TANK SHALL BE USED. 6. ELEVATIONS ASSOCIATED WITH CONTOURING ALCOVE AND FLOODPlAIN AREAS IS TO BE DIRECTED BY ECOLOGIST IN THE FIELD. 7. PARTIALLY BURY AND PLACE LOGS IN THE EXCAVATED ALCOVE, LOG PLACEMENT SHOWN IN THE PlANS ARE SCHEMATIC; ACTUAl PLACEMENT AND ARRANGEMENT TO BE DETERMINED BY THE ECOLOGIST IN THE FIELD. ANCHOR AS SHOWN IN PlAN DETAILS. 8. PLACE 6 INCHES OF STREAMBED GRAVELS WITHIN THE ALCOVE AREA. 9. PlANT EMERGENTS AND SHRUBS IN ALCOVES ACCORDING TO PLANTING PLAN. 10. REMOVE TEMPORARY STABILIZED CONSTRUCTION ENTRANCES AND REMOVE H1GH-VlSIBIUTY FENCES, AND /JJf( OTHER EROSION CONTROL MEASURES STILL INSTALLED AT THE SITE. 1 1. CONTRACTOR SHALL PROVIDE STREAM ISOLATION / TURBIDIlY CURTAIN PER WASHINGTON DEPARTMENT OF ECOLOGY STANDARDS. <Al 1. 2. 3. 4. 5. 6. PLANTING NOTES MmGATION PLANTING PlANS REPRESENT A CONCEPTUAl PLANT LAYOUT. ALL MmGATION PLANTING PREPARATION WILL BE DIRECTED IN THE FIELD BY THE ECOLOGIST. PLANTING SHALL TAKE PLACE DURING THE DORMANT SEASON (NOVEMBER I ST THROUGH FEBRUARY 28TH). PLANTING MAY BE ALLOWED AT OTHER TIMES AFTER REVIEW AND WRITIEN APPROVAL BY THE ECOLOGIST. APPLY JUTE EROSION CONTROL FABRIC AS DIRECTED BY ECOLOGIST WITHIN THE FLOODPLAIN EXCAVATION AREAS AND ALL PLANTING AREAS WHERE REED CANARY GRASS HAS BEEN COMP~LY REMOVED. IN ALL PlANTING AREAS WHERE REED CANARY GRASS IS PRESENT, FIRST MOW THE GRASS. COVER MOWED REED CANARY GRASS WITH PROPEX 8418 (OR A SIMILAR BARRIER MATERIAL AS APPROVED BY THE ECOLOGIST) AS NEEDED AND DIRECTED BY ECOLOGIST. AND STAKE IN PLACE USING UVE STAKES. PlANT STAKES AND TREES ~ DIRECTED BY THE ECOLOGIST THROUGH THE PROPEX (OR EQUIVALENT). ALl. PLANTS SHALL BE NURSERY GROWN A MINIMUM OF ONE YEAR. PLANT MATERIAL IS TO BE SUPPUED BY COMMERCIAL NURSERIES THAT SPECIAUZE IN PLANTS NATIVE TO THE PACIFIC NORTl-lWEST. PLANT MATERIAL SUBSTlTUTIONS ARE SUBJECT TO APPROVAL BY THE ECOLOGIST. 7. NO TACKIFlER, HERBICIDE, OR FERTlUZER SHALL BE USED IN THE PLANTING AREAS. <Al GENERAl NOTES 1. TO PREVENT REESTABLISHMENT OF INVASIVE VEGETATION, THE TOP 24 INCHES OF EXCAVATED SOIL IS NOT TO BE REUSED ~ FILL ANYWHERE ON THE PROJECT SITE. (D) KING COUNlY WrnAND/STREAM PROTECnON SIGN INSTALlATION NOTES: THE WrnAND/STREAM PROTECTION SIGNS SHALL BE POSTED ON THE BOUNDARY OF THE MmGATION AREA AND/OR THE CONSERVATION EASEMENT. ONE SIGN SHAlL BE POSTED FOR EVERY lS0-FEET OF THE BOUNDARY OF THE MmGATION AREA AND/OR THE CONSERVATION EASEMENT IN A PROMINENT LOCATION. SIGNS MAY AlSO BE ATIACHED TO NEW AND EXISTING FARM FENCES. SIGNS ARE AVAILABLE FOR $9.22 FROM: KING COUNlY DEPARTMENT OF DEVELOPMENT AND ENVIRONMENTAL SERVICES 900 OAKSDALE AVENUE SOUTHWEST RENTON, WA 98055-1219 t&1 King County Department of Natural Resources and Pam Water and Land Resources DiVision stormwater Servloea Section CapItal Servtcn Unit ChtisIie True, DIrector CALl. 2 WORKING DAYS Bs=ORE YOU DICl 1-800-424-5555 (UNDERGROUND Ul1tITY LOCATIONS ARE APPROx.) t.4A Y CREEK DRAINAGE IMPROVEMENT HABITAT 1IOOA1ION INiANCBENT NSTALLA1ION DETAlS AHJ NOTES SHEET 17 OF 18 SHEETS 2006-16 I I I I I I I I I I I I I I I I I I I ~~~. .~ .. - \ _ 11- \t"" ~ \ \ \. ':::;P' \' \'- ~-::...~ g + ... OF 148TH AVE SE BUFFER MITIGATION PLANTING SCAlE: It 1" .. 60' May Creek Riparian Buffer Planting. west & east of 148th Ave SE 1'1:,,-. 6-~ ~ May Creek Alcoves Planting Plan· west of 148th Avenue SE o Slza/Sp8dIIcatJons QuanUty latin Nama I Common Nama I SIzoISpoclflcatJons I QuanUty LaUnName common Name T ...... A""' ...... ...."" .... -Pluil9' O,C. --.......... 'pi .. S-4' Heisbt Full Druse Fotiqc Plant9'O.C. Popu"'-""" """=-rood 6_c.lOpOll.I·~ ...""",,,'" plant 9' a.C, TlJiljtJplklaJa Wcam ml c:cdaT 5 pl., U' Hefabt full Dmse FoIiaae Plam9'O.c.. Shru __ CanrlU urlct4 --Ban: JOOl, Minimum 36" Lana Pludl'O.C. ScJixltu..,. ""'''' ....... Live SUkcs. 61..oq. 11l-'" DiamI:te PIanlJ'O.C. S41ixWdt-u SitbwiDow Lke S1akcs, (; Lon .. Ill·'" DiII:mda Plant)' O.C. May c .... w ....... en"-_"'n·_of'_A .... * Ili.r.'...:.Jl1 T ... ~:~ 110,110 ...... WIIaa.) ..... -"-_ &I T . - Emergents .. for alcoves near stream Sdqna III:IlIm I Hanfs1an bu!brusb 260 EkocItGriI pahuIrU I CommoIl5pikt-Nlh C..u SJipaIfJ s..tJcak Rd&e SbrubsIWUJoWl 260 C~ ........ Rcd-oiscr dopood 260 PIo'JOaltJ1ll1 eopiUltUs PacUIC I1indwt 260 --Pal fnWd rose R""~ "'-21" 285' Stdu,~ ............ 28" Salk ltulalttba PacifIC willow ---I BlICk Cottoawood 'q(Plam Iro.c) Plua ('_Iaw Q,C) Plus (Piw IT O.C) I Bue tool, mi 12" Ima Plat)' a.c. I Ban: root. mi. 12" kaa PI&III)'O.C I Bue IOOl, ad. 12" toaa Plant)' O.C I Ban: mal, mi. 12" lima Pb:nI,l' O.c. LivcSUlta ,Wic&Dum fI Lq 3/4-'" "'-PImt)'O.C .......... I Mbrinnan 61oq: MinimuIa lJ4-.I" dia:mdcr Plaltl'O.C. IJvc pole cuaina I Minfmurn 6'Iq: Mirlimum 3(4".," 4IamcIer Plant l' o.c. I'op/III4 ,ridIoa1rpG ."'" """"""'" tllUIb, top Oft, 1-diamdcr 7,000 EROSION CONTROL SEED MIXES PIallt9'o.c Bate nxx. Minimum 12'" ConwSDimll --..... '00 Pbntl'Q.C live Sbkcs. tll.oaJ,lf2-t" Stdi.t~ Pxilic:wiDuw -'.000 Pbml'O.C Salix siIcbmriJ .......... Uve Silka. 6' Loztc.II2-I" '.000 -PlIDll'O.C "I'lN<TS WIlL BE IHSTALWllHROUGH·PROPEJ< (OR _IVAUI"), SEE NOItS ON SHEET III. fI!lD .... 08058 01-201 :;t --OON ALnaIJ<FR P.E. 7h011 """""'" I<INC.COlIHIY 01-2010 =. DOUO CHIN 7/2011 SIIIMY .... ~ COUN1Y 02-2010 ~ PRO.IECl lRE\IOR CRAY, PIS 02-2010 ......... DALE NELSON 7""11 SU1M.' .......... ... ......... 1_-_ -...... 1 ~ __ DE!IIQI ,.. "Xl '''' '" '" ". ,., 300 300 ". ~ '" -8 i .... .. , 8 ~ 'V WEST OF 148TH AVE SE MITIGATION PLANTING SCAlE: II: ,. = 6D' \8 ~ \ \ (UlaRoRouND unurr 1..OCAl1DNS ME SHEET 18 ti King County MAY a+ ~ DRAINAQE IMPROVB&fT OF 18 _ ........ _ .... - Water and land ReIowces DIviIIon ------...---fI.NIINIl'LM .1 I I I I I I I I I I I I I I I I I I I Appendix B -Long Marsh Creek Restoration Design Plans Impact Analysis and Mitigation Plan 31 July 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I AELD BOOK; VICINITY MAP SEC. 22, TWN.25N, R. 5 E, W.M. [j;]~\Y!!I©&®'D'ib[;! . .., ... /' I I I I I : ~~.., : c,~~ '/ c,«. t Couger j{ountain Regional Wildland Pari: Sf MAY VALLEY RD . +*":, ..... ./ " ~/ ~'1 .= " N£ 28TH ST OO~Im'D'©[j;] NE 24TH CT ~ SHEET Gl Cl C2 C3 SWPPI SWPP2 L1 L2 ----------: '------ l:i NE 24TH ST w % ~ ~ ,____ Z I ----- I I w I '" I W I .. I r I ... I ~ I INDEX DESCRIPTION , " VICINllY MAP AND SHEET . INDEX ~ I \ EXISTING CONDITIONS PLAN, CHANNEL PROFILE, LEGEND AND ABBREVIATIONS , " PROJE LOCATI GRADING PLAN AND PROFILE -LONG MARSH CREEK AND MAY CREEK SIDE CHANNEL CROSS SECTIONS AND LOG DETAILS . TEMPORARY EROSION AND SEDIMENT CONTROL PLAN AND NOTES TEMPORARY EROSION AND SEDIMENT CONTROL DETAILS PLANTING PLAN AND NOTES PLANTING SCHEDULE AND DETAILS 2010-2 9 20101 APf'RO~ ~!l Althauser, P.E. -'7-2011 SURVEYED: Gou1et,Radella 8 2010 ~~~ Doun Chin 7 2011 D£S1GNED: WES KAMEDA, P .E. I PROJECT No. 7-2011 Julia Tumev LG. 7-2011 SURVEY BASE 1oW': Radella 9-2010 CHECKED: Dale Nelson 9-2010 BY I ~TE • OESJGN DnIRED: L TRAXlNGER 7 2011 -I~~~~~ HU". EVISION lC1205 • W King County Department of Natural Resources and Parks Water and Land Resources Division Stormwater Services Section Capital Services Unit Christie True, Director Department of Natural Resources and Parks LONG MARSH CREEK RESTORATION CONFLUENCE TO RIVER MILE 0.05 tQ King County Department 01 Natural Resources t:nd PartG Water and Land Resources Division StorJrr,¥ater Services Section capital Stlrvlca Unh Chtfslie True, Di8ct!;x LONG MARSH CiiEEK REST0RA11ON CONR.UENCE TO R.M. 0.05 VICNTY MAP /IK) SHEET NlEX SHEET G1 OF 8 SHEETS 2006-42 \ \1 ",'"'./ \// BARN 5''''0''' " / / '" ~¢ ","''V<;j:::.<':'''' ","''V¢''''''' /' ~\~0 /' ~ \ GENERAL LEGEND: , ___ '1' __ _ \ /'.,::.S /' nNt. 1 MA,\Si1! CR(EK '" '" ~ '" --all. ~ A!liJ&III~"--/ ---"-,, /\ // \ --.(--Y.--).- EXISTING WETLAND BOUNDARY EXISTING STREAM/CREEK EXISTlNG WIRE FENCE \ _\ - / / / \--- / / / I \ \ / / '" U'. / \ \ HOUSE ;. I!IZI' ___ IIililIIiI EXISTING 165' STREAMM BUFFER .1 I I. I I. I I. EXISTING 42". STORM DRAIN CULVERT \ ( \ \ \ HARO~tg GAMBINI, JR \ 15019 $£. MAY VALLEY RD \,.,...,..-/ @ ~ !t. L ~ ~ :.t. WHITNEY & JEFFREY WALKER 15125 S.E. MAY VALLEY RD ~ ~ --I --\ S \ \ \ ---- STREAM BUFFER LONG MARSH CREEK _1: -. :_, :_:1:_ //'\ // \ \ POLLUTION PREVENTION PLANS HYDRAUUC PROJECT APPROVAL TEMPORARY EROSION AND SEDIMENT CONTROL CONTOUR INTERVAL = 2 FT. _ Jc~~~l~ ~ J ~--tl, t-i"¥=,,,,~,:;:;t";;;~i~~;;3! '--::;-,j 21l'::::-_1_.2 32h-~ --: . ..J.-"-=------325 If Iii I I l 1~~ i J _ 2~4'!i. L24"j_~~::':~:~::~~;:~::~:::~":::::"1""":::L,,,,"::~ -;'--~ ------t------r-----i------+------t----~------~----~, 320 i J-;S9% t:::---'='-i-.!?c9i" ---1 -T ElXISTINr, TON~ ~I-l (,R~~I( ~ -315 CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 , '6'+00---+1--'-;------;100 -l--+------i-;:ClQ'----SC&E1'~20' ~ORIZ::_'" l' VERT '.00---:-----11 -L-----+-J----i---, -310 (UNDERGROUND UTIUTY lOCA.TIONS AAE APPROX.) APf'RO'IE): Don A/thouser, P.E. 17-2011 1 PRo..ECT .. ANAGER: Dou Chin DESIGNED: WES KAMEDA, P.E. PROJECT No. lC12U:J DESCN MAINTENANCE DJVlSION No. t&1 King County Department of Natural Resources and ParQ Water and Land Resoun:es Division Stormwatef Servloes SectIon CapItal Setvk:a Unit CIlrlstie Troe, Ditector LONG MARSH U\EEK RESTORAllON CONR.UENCE TO RM. 0.05 EXISTNl CXHlI110NS PLAN, OWIEL PROfI.E LEQEN) NC A EYlAlIONS SHEET C1 OF 8 SHEETS I I I I I I I I I I I I I I I I I I I ~ o 1 22, TWN.2SN. Ir- V / / / I I I \ \ \ CONSTRUCTION SEQUENCE, 1.HOLD PRE-CONSTRUCTION MEETING AND NOTIFY PERMIT AUTHORlTlES OF THE PROJECT START DATE. L j /1 :' I / / HAROLD GAMBINI, \JR 15019 5.E. MAY VALL~Y RD @\ 2.KING COUNTY ENGINEER OR ECOLOGIST WILL fLAG THE CLEARING AND GRADING LIMITS AS SHOW ON THE PlANS. 3. TREES TO BE PRESERVED SHAlL BE FLAGGED BY THE KING COUNTY ECOLOGIST. A.INSTALL SILT FENCES WHERE DESIGNATED ON THE PlANS. IMPLEMENT THE TESC , I i-- I ----~-.. ------~ ,,-) -_.------_._=-..--< __ 1 ----r...........- ) CHANNEL \ --~)(--J'_~'\j:. __ NEW FENCE CLEARING AND AS NEEDED I I ., , ,- \ ;.. l -, \ \ / B?ULDER DETAIL ffi NE~\·\ ~~ ON... /! \ /" I ~~\ \ \ \ '\ \WHITNEY & \ \'25 S.E. \ 330 , I I I . I ' 330 I , I ' , I I I .J ___ J. ._L .. __ ""-+ ____ "_ .. _____ i ~ ___ i ... __ .... _______ .L __ J ___ ._. _1. ~_l J~--.-.---... --......~! _ .. --"-::':~:_:::::?!:;I I ! imJIlNG I . ; ~~ ':;'~JD M;rE Btk~£U:66g ~uf°fot. i""".~:::::::::f .. ::::.::::\;~~;~~r. ~;,:;: O-li 2;7" li ll'. ! 'GROUND t ~CHORING iAND EMBE;DMENT I : / '06.86 Lf. 42 t CO, i ' I I I I . .. :, I 12."% -----------------, ---f----~I----I ~ ./ \----= ~ -'C _.L,---=--~----~---------f------==f=-:.::.:.:.:::-:r-j --+-.- ! j 1 1--~ --J_ ~ i 1 -~~~ 73; I! , , ' __ , -• .' I I _--I If" 1 ; ; CHANNELAj 1 ! i I -~---l-~-"+ -----+-·--~··~-f--! ~; ~-----+----IN~ELALCUTVERT---r___-!--.-'"---+----------~--." i I -t ' I '_24B~ r I ' , STAl EQUATION I I ! : LONG MARSH LOW FLOWj CHANNEL i STA, 0+00 (EL 309;00)= ___ ~y, .c:R~Q< lSID!' _~HNL STA 0+42.07 . ,I I 300 I ! I I: I : : 1300 0+00 1+00 2+00 3+00 3+90 -320 --------i-_·------L---+310 IPRAP, PROTECT]ON , ! ; ----··-+--------+-------t-·-------"-.- nEW :~'~:~~2!O~1!O!-!2t19~2~0~1jOl~~~!i~il;!ii~~I~!;1 APPROVED Don Althauser P.E. 7-2011 SURVEYED: Goulet,Radelia 8-2010 PRo..£CT SUIM:Y BASE 1iW': Radella 9-2010 W,,"AGER: Doug Chin 7-2011 CHECKED: Dale Nelson 9-2010 DESIGNED: WES KAMEDA. P.E. 7 2011 PROJECT No. 1C1Z0:::' Julio Tum~ L.G. 7-2011 DESIGN ENlERED: L TRAX1NGER 7 2011 MAINTENANCE DMSION No. \ \ PLAN. PREVENT SEDIMENT FROM ENTERING THE WATER AT ALL TIMES. INSTALL ADDmONAL lEse MEASURES TO SUIT THE CONDITIONS AT THE TIME OF CONSTRUCTION AND /J.S REQUESTED BY THE-KING COUNlY ENGINEER OR ECOLOGIST. 5.BYPASS LONG W,RSH CREEK FlOWS PER THE TEse PlAN. 1--6.EXCAVATION WITHIN THE STREAM CHANNEL SHALL TAKE PLACE ONLY DURING THE FISH WINDOW AS DESIGNATED IN THE HPA. 7.FlNAL GRADE/STREAM CHANNEL ELEVATIONS ARE SHOWN ON THE PlAN. OVEREXCAVATION OF ROUGHLY 6 INCHES AND BACKFILLING WITH STREAMBED GRAVELS IS REQUIRED WITHIN THE LONG MARSH LOW FLOW CHANNEL AND THE MAY CREEK SIDE CHANNEL. EXISTING ONSITE STREAMBED GRAVEL MAY BE REUSED. 8. WHILE EXCAVATING THE SIDE CHANNEL IN MAY CREEK, AN EARTH PLUG SHALL BE LEFT BETWEEN THE EXISTING STREAM CHANNEL AND THE EXCAVATION. A SILT CURTAIN SHAll BE DEPLOYED PRIOR TO REMOVAL OF THE EARTH PLUG PER TESC NOTE NO. 7 SHEET SWPP1. 9.CHANNEL/BENCH WIDTHS AND LARGE WOOD PLACEMENT ARE TO BE ADJUSTED IN THE FlELD BY THE KING COUNTY ENGINEER OR ECOLOGIST. . 10.0VEREXCAVATE AND EMBED AT LEAST HAlf OF THE LENGTH OF THE LARGE WOOD PIECES UNDER BACKFILL AND BOULDERS. 11. PLANT EMERGENTS AND SHRUBS ACCORDING _TO THE PLANTING PLAN. 12. REMOVE THE TESC MEASURES AND FLAGGING. 13. RESTORE AND/OR RESEED AN( AREAS THAT WERE OISTRUBED BY THE CONSTRUCTION. 2 FT. [Sid';-Channel MoyCRK PROFILE I Station ~ ~ "" ~ ~ ;.<, ~ ~ 3201 ,1320 I rt~~~G 31 1 bI=-~ .--~~. ...--': ., ./ i ' ,DESIGN i ,: ; GRADE 31 . 2.3B" 0.5' STREAMBED GRAVEL . -310 30 I 305 0+00 1+00 EQUATION STA. 0+42.07~ STA. 0+00 LONG MARSH CREEK EL.~309.00 CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 tQ King County Department of NabJraI Resources and Par1uI Water and Land Resources Division ---Capital Servk:es Unit Christie TnI8. Dir8ctor (Ut«RGROUND UTIUn LOCAllONS ARE APPRox.) LONG MARSH U\EEK REST0RA11ON CONR..UENCE TO R.M 0.05 CJIADINQ PLAN AN> PIIOR..E I..ONQ IIAFtSH a'EEK-MAYa'EEK SI)E 0iANB. SHEET C2 OF 8 SHEETS I I I I I I I I I I I I I I I I I I I ~OG .. ~_B.o!JJDfR NOTfS: --------, I. U;)~ LVuS WITH ROOT WMJ ATTACHED. 2. LOGS MUST BE BETWEEN 1 S-INCHES TO 3O-INCHES IN DIAMffiR AND BETWEEN 12-FEET TO 20-FEET IN ""'" \ I V-I I I I I I, . L LENGTH. _ '\ Ii I , ___ , /~ , 3. LOGS SHALL BE WESTERN RED CEDAR OR DOUGlAS FlR. " / Y I J 'I J. ,,( I 4. BOULDERS SHALL BE GLACIALLY WORN AND ROUNDED ~", ....... /' II 3D' .L ! ....... ~ -.. IlL--..1- S,REA" 6M'K --"'-" . _ ... "- AND TO INCREASE HABITAT COMPLEXITY. x ~ ~ ! : ,f /~ ! 1 "":-..... .. '\\ \;' ,~l i // , x (BOTH iSIDES) I ~ FLOW 6. BOULDERS WILL BE USED TO AID IN ANCHORING LOGS '\ \~ rf{/ f'/' ill;' \. \, I h I / j' I NOTE ON SHEET C3 5 ~~:~~~thlH~;ogu~;;G~~:~~~~T~~EA 1-~1-' ~.\~.:II.r ~C-______ . I __ ~~E_RA_G_E_D: A:C_~ __ ::r~E~_EXIST~::. FE~CtE: __ J ___ . J. _~,,~ ~.1. ~~7-.. ~. ________ .~. __ ... __ ... fENCE.+-. _ ... __ !_ ... __ .. __ . MIN. OF lS" SOIL COVER. '\-, ~'~' it ':1 I~/ I --------r II ' '\ '\ I ;7"---TT 1 ·-··· EXISTING AND NEW PER l':;:::~~~~~==~~~~~: 7. THE EXACT PLACEMENT OF LOGS AND BOULDERS IS TO I~i '\ Ifl ,f/-DECIDUOUS TREES-! -------... \1 i.l It! ~...... I i NK BE DIRECTED BY THE ENGINEER IN THE FIELD. ~'. ,; " (PRESEi<VE-FtAGGElrTREES) ,,---'.' 1t' l' " I S1RV',,6~ ~ Ilj!IJ:~ I I I '"" I. " I I ~ ~ I ~ \;l.t7 i i .,~\.il !'~ .-.,,~, •• ~ ..... ..-........... EXISTING "\ 'I \) II I I ! ~" ""i.'.!' PADOOCK~ x "" I j '"\j1' Ix / ANCHOR AND DEFLECTOR BOULDERS 28"-36" (3 MAN) LOG AND BOULDER PLACEMENT DETAIL fT\ C2 '-" -t~ll~ Ji, ~~}I =-.EM£RL ~ Ilf ~~JII /J2i7-+---':""-1-- "1S lB~ MINIMUM SOIL COVER A MINIMUM OF 1/2 OF LOG SHAlL BE BURIED ALONG LENGTH WITH STREAMBED GRAVEL AND SOIL LOG IS 20' LONG AND 1 S" _30" DIAMETER. STABILIZE WITH 2B~ TO 36~ BOULDERS ON TOP OF LOG, ALONG AT lEAST 1/2 LENGTH OR ALTERNATIVE ANCHOR EQUIVALENT . • _0 .0 •• • •• "!. .• '. _0_. m~·J;/°' (---lS.00 16.00 14.00 WEIGHT REiD BOOK: SURVEYED: ~~~----- STR~BED GRAVEL STREAMBED GRAVEL 1 1/2 INCHES I US STD. SIEVE SIZE PERCEIfr PASSING BY 3/4 INCHES 18 INCHES 95 100 3/8 INCHES 12 INCHES 90 95 NO.4 9 INCHES 80 90 NO. 40 6 INCHES 70 80 NO. 200 4 INCHES 55 70 18 INCHES LOG AND BOULDER PLACEMENT SECTION © " ---- IS C5 C3 ----"-"-"- '---' , 45-60 30 50 25 35 16-30 1520 o 5 18 INCHES /' / /' ./ I 2 / / ,/ Y SCALE IN FEET ~ / / '~ -- MAY CREEK MAiN , CHANNE~ ---EL=30B -" 2010-2 9-201 Goulet,Rodelio 6-2010 OVEREXCAVATE AND PLACE 6" ~'N . ./ DEPTH smpMBEO GRAVEL l::£Q.U PRo.ECT t.lANAGER: Doug Chin 7-2011 SURVEY BASE t.IAP: Rodelkl 9-2010 '\'i I PROJECT No. OESICHED: WES KAMEOA. P .E. 7-2011 ~ 7-2011 ~I~~~~~~ CHECKED: Dole Nelson 9-2010 Julio Tumey LG. OESIGN EHlERED: l. TRAXINGER m.s.o.. NUt.I. 8Y I OATE 12.00 r- lC1205 • 10.00 8.00 6.00 '.00 2.00 'I. 2.00 4.00 6.00 S.OO 10.00 12.00 14.00 16.00 lS.00 20.00 LONG MARSH CREEK TYPICAL CHANNEL SECTION fA\ EMERGENTS~ I ~'. --'-• __ -i ~ . ~AY CREEK , SIDE CHANNEL SECTION "1S "1S C2 '-" _~'l ---314 -" ~OG WITH ROOTWMJ fB\ C2 '-" ti King County Department of Nalural Resourt:8llDl PariaJ Water and Land Resources Division Stormwaler ServIoea Section capital ServIca Unit ChriStie True, Diet:tor -t.A1'::>11!' PASTURE _-1-_1.- c~ 2 WORKING pAYS BEFORE YOU DO (UNDERGROUND UTlUTY LOCATIONS ARE APPROX.) LONG MARSH CREEK RESTORATION CONR.lJ8IICE TO RM. 0"05 SHEET C3 OF 8 aI05S SECTIONS Nf) LOG DETALS I SHEETS LONQ MARSH a&K-MAY a&K SIlE CHANEL 2006-42 I I \ , \ \ , I I l. I I I I I \ I I \. ;"-1 I I I I ~ I I )~ / \ / " 1 ;.. \ 'i' , / \ ' / /.( "\ / \ I t I AElD """'" 2010-2 9-201 SURVEYED: Goulet,Radelia 8-2010 SURVEY BASE NAP: Radella 9-2010 a<[CKEI>. Dale Nelson 9-2010 I NUN. ''''''ON ~, ~. ~\ r- oo I ",. ~, oo- ~- '-ID.tPORARY BYPASS .. FLOW \ 8 t> PVC PIPE \,~~ " \ (.o-l -I ~ "' ~ '" \ W!' /~ (( SEd. 22, TWN.2SN, R. S E, W.M. " \ \ - ffi SILT FENCE----.... S'M'P2 '-' _"'. __ )( ____ .~ -_"i.-- ----I' II 'BARN ----- II II II II II II I Ii / / / \ \ \ ;rORE :ONSTRUCTlON STAGING AREA TO ORIGINAl CONDmON ~.L 4 ~ ~ ;.L. ~~~ \ ~ ~ ",,-< ././ o<:?--\'2-./--.... ./ O\<:?--"\,/ \ ././ "5,\>{:.G ././ CREEK 't..'f...\S./ \ ~ ~ , ;..~ ;_,,-"-1_:; ./ ----\ ~ -\ / r \-\ I I I HOUSE \ I J _ \ -i I \ r I ~ I \ m ~ ~ ~ \ HAROL~ GAM8INI, JR \ 1§Q1.9-s:t:_ MAY VALLEY RD -@ WHITNEY & JEFFREY WALKER 15125 S.E. MAY VALLEy RO ----I @ 1 1 1 1 L.. ___ _ / TEMPORARY EROSION AND SEDIMENT CONTROL NOTES: 1. ALL WORK ON PRIVATE PROPERTY WILL BE CONSTRUCTED USING A TEMPORARY CONSTRUCTION EASEMENT. THE DRAINAGE SYSTEM ON PRIVATE PROPERTY WILL NOT BE MAINTAINED BY KING COUNlY AfTER COMPlITION OF THE PROJECT. 2. THE ESC FACIUnES MUST BE CONSTRUCTED IN CONJUNCTION WITH ALL CLEARING AND GRADING ACnvmES,AND IN SUCH A MANNER AS TO INSURE THAT SEDIMENT LADEN WATER DOES NOT ENTER THE DRAINAGE SYSTEM OR VIOLATE APPLICABLE WATER STANDARDS. (KeC 9.04.020 M, KCRS 7.09 D). 3. THE PROJECT SHALL BE SCHEDULED FOR CONSTRUCTION IN DRY CONomONS. LONG MARSH CREEK SHALl BE BYPASSED AROUND THE CONSTRUCTION AREA. 4. ALL WORK SHALL COMPLY WITH THE WASHINGTON STATE DEPARTMENT OF fiSH AND WILDLIFE HYDRAULIC PERMIT APPROVAL CONomONS. 5. THE PROPERlY OWNERS SHALL BE CONTACTED ONE WEEK PRIOR TO CONSTRUCTION. 6. AFTER COMPLETION OF CONSTRUCTION. THE STAGING AREA AND THE DIRT PATH SHALL BE RESTORED TO ORIGINAL CONDmONS. AlL OTHER DISTURBED AREAS • SHALL BE SCARIFIED. MULCHED AND SEEDED . 7. A SILT CURTAIN. AS DIRECTED BY THE WLRD ECOLOGIST OR ENGINEER, SHAlL BE DEPLOYED IN THE EVENT OF TURBIDIlY PRODUCING ACTIVITY. 8. SEDIMENT LADEN WATER SHALL BE PUMPED INTO AN UNPAVED UPLAND AREA WHERE IT CAN SHEET FLOW THROUGH VEGETATION PRIOR TO RE-ENTRY INTO MAY CREEK. 9. ALL PAVED ROADS USED FOR INGRESS AND EGRESS SHAlL BE KEPT FREE FROM SEDIMENT ACCUMULATION BY SWEEPING AND/OR WASHING AT LEAST ONCE PER DAY. 10. HAND BROOMS AND OTHER APPROPRIATE TOOLS SHAlL BE USED TO REMOVE SOIL AND ROCKS FROM CONSTRUCTION VEHICLE TIRES PRIOR TO EXmNG THE SITE. 11. THE fOLLOWING BMP'S SHALL BE ONSITE OR READILY ACCESSIBLE DURING CONSTRUCTION: MULCH. STRAW WATTLES AND/OR STRAW BALES SILT fENCING AND SILT CURTAIN SPILL RESPONSE KIT 12. THE CONSTRUcnON UMITS OF THIS PROJECT SHAlL BE DEfiNED BY THE CULVERT ON THE UPSTREAM END. THE EXISTING WIRE fENCE ON BOTH SIDES OF LONG MARSH CREEK AND THE SILT FENCE ON THE DOWNSTREAM END. EXCEPT FOR AN ADDmONAL 5 FT BEYOND THE FENCE AT THE MAY CREEK SIDE CHANNEL AND A PORTION OF THE SOUTH SIDE OF LONG MARSH CREEK. TESCLEGEND ~ - ----5'--- -CL- ---'1'--- ~ ~ --~C&G--- TEMPORARY BYPASS PUMP TEMPORARY 8-' BYPASS PIPE SILT FENCE SIt T CURTAIN TEMPORARY BYPASS PIPE/HOSE CLEARING UMITS UNE EXISTING WETLAND BOUNDARY EXISTING STREAM/CREEK CONSTRUCTION ACCESS ROAD Cl£ARING AND GRADING UMITS ) --------~ \ " .... !. CALL 2 WORKING DAYS as=a:e YOU DIG 1-800-424-5555 I SCALE IN FEET _. CONTOUR INTERVAl = 1 FT. APf"RO'ofil: Don Althauser, P.E. __ __ 17-2011 PR<>£CT MANAGER: Ooua Chin 7-2011 DESIGNED: WES KAMEOA. P.E. 1 PROJECT No. lC1205 7 2011 Julia Tumev LG. 7-2011 BY I DATE • DESGN ENTERED: L. TRAXINGER 7-2011 I ~~~~~ • til King County Department d Natural Resources and Parks Water and Land Resources Division SIl:m1Wat8t s.vIces SedIon Capital SeMca Un« CMstie TfV8, DinIdot" (UNDERGROUND lJTlUTY LOCATIONS ARE APPROX.) LONG MARSH cnax RESTORATION CONR...UENCE TO R.M. 0.05 1BIPORARY EROSION »D SECIIENT CONIlIOL PLAN »D NOTES SHEET SWPP1 OF 8 SHEETS 2006-42 I I I I I I I I I I I I I I I I I I fiELD BOOK; 2010-2 SlIRYM&. Goulet.Radelio SURVEY BASE MAP: Radello CHECKED: Dale Nelson I JOINTS IN FILTER FABRIC SHALL BE SPUCED AT POSTS. USE STAPLES, WIRE RINGS. OR EQUIVAlENT TO ATTACH FABRIC TO POSTS 2"X2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC -Tr, - -6'!:iAx. - - --n -, I I \ • I I MINIMUM 4 "x4" TRENCH U ~ACKFILL TRENCH WITH NATIVE SOIL OR 3/4"-1/5" WASHED GRAVEL POST SPACING MAY BE INCREASED TO 8' IF WIRE BACKING IS USED 2"x4" WOOD POSTS, STEEL FENCE NOTE, FILTER FABRIC FENCES SHAlL BE POSTS, REBAR, OR EQUIVAlENT INSTALLED ALONG CONTOUR WHENEVER POSSIBLE SILT FENCE DETAIL NTS AlUMINUM b'l I IL ;" \ \~SION CABLE BELOW FLOTATION GROMMETS LACED . TOGETHER WITH MANILA ROPE ( "' U"'~' Tt"~'C"I"'U"'1"\ TUO"" I, f1\ SIII'Pl "--'" FLOTATION STRESS BALLAST CHAIN PLATES. VIA HOOK AND RING CONNECTION 9-201 8-2010 9-2010 9-2010 SILT CURTAIN (TYPICAL) f3\ NOT TO SCALE -NIl •. ION BY I DATE SWPPl '-'" Af'PRO'£D: Don Althouser, P.E. ~~~ Douo Chin DES\QEt): WES KAA4EDA, P .E. Julio Tume LG. [)£SIGN ENTERED: L TRAXINGER z ::; N ~>~~~ N ",,,,,'<- G ?'" ,<-i-\c,~'i' HOG FUEL OR rJ ... SS ~G 12" MIN. 9EPTH~ 4"-8" QUARRY SPAlLS OVER GEOTEXTILE FABRIC TEMPORARY CONSTRUCTION ACCESS NTS STEEL PLATE OR SANDBAGS ACROSS WIDTH OF CHANNEL CONSTR"CTION ACCESS NOTfS' 1. THE ENTRANCE SHAlL BE MAINTAINED IN A CONDITION WHICH Will PREVENT TRACKING OR FLOW OF MUD ONTO puauc RIGHT -OF-WAY. THIS MAY REQUIRE PERIODIC TOP DRESSING WITH 2" STONE, AS CONDITIONS DEMAND, AND REPAIR AND/OR CLEAN--OUT OF ANY STRUCTURES USE TO TRAP SEDIMENT. 2. ALL MATERIALS SPILLED, DROPPED, WASHED OR TRACKED FROM VEHICLES ONTO ROADWAYS OR INTO STORM DRAINS MUST BE REMOVED IMMEDIATELY. 3. PROVIDE TRAme CONTROL AND ROAD SIGNAGE FOR CONSTRUCTION VEHICLES ENTERING AND LEAVING SITE. 4. COORDINATE WITH THE PROPERTY OWNER REGARDING THE EXACT SIZE AND LOCATION OF THE TEMPORARY CONSTRUCTION ACCESS TO AVOID DISRUPTION OF THE HORSE BOARDING ACTMTY ON THIS PROPERTY. REMOVAl OF THE QUARRY SPAlLS MAY BE REQUIRED AfTER THE CONSTRUCTION. 5. HOG FUEL MAY BE SUBSTITUTED FOR THE QUARRY SPAllS DEPENDING ON WEATHER CONomONS. AT THE DIRECTION OF THE WLRD SITE REPRESENTATIVE. EXISTING [ 48"\& CULVERT STEEL PLATE AND/OR COFFER DAM o ... ~. <_."'. . ..• _ ~. . ....... ..:: r ----~ PUMP TO STABLE CHANNEL '(DOWNSTREAM) Q - - - - . ,. .. < •• ~ ....... ,.... • 17-2011 7-2011 7-2011 7-2011 4" PRIMARY PUMP (6" PUMP ON STANDBY FOR WET CONDmONS) 1 PROJECT No. 1C1205 7 2011 I~~~~~ • 2" SECONDARY PUMP (4-PUMP ON STANDBY FOR WET CONDmONS) '-_________ TO STABLE CHANNEL, BEYOND ACTIVE WORK eJ.& AREA (DOWNSTREAM) STEEL PLATE AND/OR SANDBAGS WITH 40 MIL POL YETHYL£NE SHEETING OR EQUrvAlENT ELEVATION TEMPORARY STREAM BYPASS PUMP, DAM AND PIPE DETAIL (4\ NTS ti King County Department of NatlJraI Resources and PaU Water and Land Resources Division StormwatBr ServIces Sec::IIon capital s.rvtces Unit Christie T roe, Diredor ~ LONG MARSH CREEK RESTORATION CONR.ue«:E TO RM. 0.05 1EM'ORAfII' EftOIION /IK) _ DETALS SHEET SWPP2 OF 8 SHEETS 2006-42 j I I I I I, I I I I I I I I I I I I I I \ " \\ ~\ \ , \ \ \ \ \A \ \ \\ \ \ \\(~) \ \. .: )c \,/ \ "-' '~\ '\ ~ " /\1'" / 1~ ,tl\ [)I\ ) ~ \ ~ \ / : , ~ ... /p "\ /\ // \ . /"". / ,.,(/ \ \ \ / It /~ \ \ \ \ \ ~\ i""~ \ SEC·t 2, \ \ ./ / / -L NEW FENCE ..- ALONG PROJECT LIMITS /' AS NEEDED /' /' / .. /i. ',. \ \ / / / \ . __ '( _ '-:'ii / / / LIMITS (/ \ \. \ \ / \ \ ,~ \ ~,' ~I""""""'" '//1 / \ / \ /X/ -- \./ \ \ \< -- \ \ \ ---- C;\Rt:P-"-" eurf£.R-""'''' \ -, \ \ \ \ \ \ / 'h'H1TNEY & JEFFREY WALKER 15125 S.L MAY VALLEY RD / > 9>\ % ...--... --- . ..-'~7'";y''::' S PRo..ECT -17-2011 I . . ., WAHAGER: Doug Chin PROJECT No. I \,.; I ~u PlANTING DESIGN, DE'ON MAINTENANCE DIVISION No. --- ---c _D "GAMBINr~~ VALLEY-,.R D --- - \ \ --- \ \ \ \ ~ ~ L ~ ~ ;.I.. \ PLANTING NOTES: \ \ \\ 1. PRIOR TO MmGATlON CONSTRUCTION, CLEARING LIMITS SHALL BE ~ ~ CLEARLY IDENTIFIED WITH ORANGE PlASTIC FENCING. KING COUNTY'S BIOLOGIST SHAll VERIFY AND APPROVE FENCE LOCATIONS PRIOR TO CONSTRUCTION. 2. CONTRACTOR SHALl ARRANGE TO MEET ON SITE WITH ENGINEER AND BIOLOGIST PRIOR TO THE COMMENCEMENT OF CONSTRUCTION ACTMTIES TO DISCUSS ACCESS, UMrTS OF WORK AND METHODS. 3. MmGATION PlANTING PlANS REPRESENT A CONCEPTUAL PlANT LAYOUT. FINAl PlANT LOCATIONS SHAlL BE DETERMINED AT THE TIME OF PlANTING BY THE BIOLOGIST. 4. WITHIN ALL DISTURBED AREAS TO BE PLANTED OR SEEDED, PROVIDE AND INSTALL FOUR (4) INCH DEPTH OF COMPOST ROTOTILLED TO A lWELVE (12) INCH MINIMUM DEPTH. 5. ALL PlANTS SHALL BE NURSERY GROWN A MINIMUM OF ONE YEAR. PlANT MATERIAL IS TO BE SUPPUED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PlANTS NATIVE TO THE PUGET SOUND REGION OF THE PACIFIC NORTHWEST. PlANT SUBSTITUTIONS ARE SUBJECT TO APPROVAL BY KING COUNlY'S BIOLOGIST. 6. PlANTING SHALl TAKE PLACE DURING THE PLANT DORMANCY PERIOD (NOVEMBER 1 ST TO MARCH 1 ST), OR AS DIRECTED BY KING COUNTY'S BIOLOGIST. 7. THE CONTRACTOR SHALL BE RESPONSIBLE FOR DISPOSING OF ALL DEBRIS AND EXCESS SOIL EXCAVATED BY THIS PROJECT. CR'-C\", .• \ -\:: 8. CONTRACTOR SHALL VERIFY THE LOCATION OF ALL UTlUTlES PRIOR TO EXCAVATION. 9. EXISTING AREAS DISTURBED BY CONSTRUCTION ACTIVITIES AND NOT SHOWN TO BE RE-VEGETATED ON THESE PlANS SHALL BE RESTORED AND SEEDED, AS DIRECTED BY THE ENGINEER. 10. DISCREPANCIES BETWEEN THE PlANS AND SITE CONDmONS SHALl BE BROUGHT TO THE AlTENTION OF THE ENGINEER AND BIOLOGIST PRIOR TO PROCEEDING. 11. NO TACKIFIER, HERBICIDE OR FERTlUZER SHALL BE USED IN THE STREAM PlANTING AREAS. CONTOUR INTERVAL c:: 1 FT. CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 (UNDERGROUND UTIUlY LOCA.T1ONS ARE APPROX.) SHEET L1 ~ King County Oepartmerrt of Natural Resources and Par1aI Water and Land Resources Division LONQ MARSH CALL< RESTORATION CONR.UENCE TO RM. 0.05 OF 8 -....".",-capital Serv\c:eI: Unit f'LAN1N) PLAN f>H) NOTES ChrtsIie True, Dir'ector I J I Nama I I Long Marsh Creek b I "*" 0 I 0 IFraxlnus Iatifolia I 0 0 I 0 I 0 I 0 I @ * 30 ~ I PoJvstichum munltLm iWesf<wn SW«d Fem I I .., 10 cubic inch Inch PILIgS or 4"po1 I I I ...... no 50 I I I I I Slope edge locate in "wiI_ High flow channel, base distributed stong CtOOk distributed along creek "*" I Red Cedar 0 vomu~ ~em;ea Red 3 Osier Dogwood ,0.;;" ~:? Symphoricarpos Snowber 6 albus ry Shore 6 lenticularis Sedge l.flUil 6 ted Bulrul 0 Salix iaslandra Paci1i 0 Salix sitchensis Sitka Willow TREE STAKING "ARBOR TIE" DR APPROVED SUBsnTUTE -------~, 8'-0" "lIVe" LODGE POLE PINE STAKE, 2" DIA. (1 PER TREE) ORNEN INTO UNDISTURBEO DIAGONAJLlY SUBSOIL MIN. 24" DEPTH-------------- !IQIE;: STAKE ALL TREES .' AND TALLER. BACKFILL WITH MIXTURE OF 1/3 COMPOST AND 2/3 NATIVE SOILS. WATER AND TAJMP TO REMOVE AIR POCKETS. SCARIFY SIDES OF PLANl1NG PITS PRIOR TO BACKFlWNG. !!llIt: DECIDUOUS TREES SHALL HAVE TWO STAKES FOR SUPPORT. INSTALLED PERPENDICULARLY PER u.s. HORT. STANDS. 20 full. dense foliaae. 1 gal Container min two stems 1 gal Container min two stems 10 cubic inch I _ •• "... .." .... _ Uve stake, min 36" long at y.-to % • diameter, min 12 lateral buds per stake ,-PlANT SO THAT TOP OF ROOT BALL IS EVEN WITH THE FINISHED GRAJDE '-r.n",n:· OF HAND TOPSOIL PlANTS side channel "Island".between main and side channel I side channel I!QI&: MIN. 12 NODES BElOW GRADE PAINT OR DIP EXPOSEO ENOS OF LIVE STAKE WITH WHITE LATEX PAlNT PRIOR TO INSTAllATION LIVE STAKE INSTAUATION: iNSTAll LIVE STAKES AT MIN. 36-SPACING. INSTALL PER DETAlL POKE HOLE IN SUBGRADE WITH SlEEl BAR. CAREFULLY PlANT STAKE IN HOLE. 00 NOT BREAK OFF LEAF NODES. CAREFULLY FIRM SOIL AROUND INSTALLED LIVE STAKE TO REDUCE AlR POCKETS. , driven into banks distributed LIVE STAKE DETAIL ffi along island between May Creek main and side channel 3 'oc staggered Stakes driven Into bankS distributed along creek 2" DEPTH loS A MULCH. KEEP MULCH AWAY FROM MAIN SlEM --------~ FORM SAUCER WITH 3" CONTINUOUS RIM BACKALL WITH I.IIXTURE OF 1/3 COMPOST & 2/3 NATIVE SOILS. WATER AND TAMP TO REMOVE AIR POCKETS. SCARIFY SIDES OF PLANl1NG PITS PRIOR TO BACKFlWNG. ----- l!IQ!E: NTS r-F1NISH GRADE SOIL CONE OF HANO FIRMED SOIL FOR ALl PLANTS "BUTTERFLY" ROOTBALL PRUNE DEAD OR BRDKEN ROOTS. SUCE THROUGH ROOTS CIRCUNG THE BALL SPREAD ("BUT1ERFLY") ROOTS ON BARE ROOT & CONTAINERIZED ut-TERIAL SMALL TREE, SHRUB '--/ CONIFEROUS TREE PLANTING rT\ AND GROUND COVER PLANTING f2\ N15 O'RO.£CT 1'-'''''' I . MANAGER: DOug uun PROJECT No. .\", L~ PI.ANl1Nr; 1 •• 11-T •• __ • I... .,-"" •• DESIG1< DESIGN EN1ERfD: L. IraXlnger 1/-~Ul1 I MAINTENANCE OMSION No. '---" ti King County Departmant d HarurII ResaWaIe and ~ 'Haler and Lantl ReSOJrces DIvIsIon ----_ .... ~ Trw, Dhc:far .15 '--/ CALL 2 WORKING DAYS BEFORE YOU'OO 1-800-424-5555 (\.M)ERGROUND UTIUJY LOCAlIONS ARE. N"PROX.) LONG MARSH CREEK RESTORATION CONR..UENCE TO RM. 0.05 SHEET L2 OF 8 PI..ANTNI3 SCIEDI.l.E NO CETALS SHEETS '. . ~ - ". '. J I I I • • I I I I I I • • I I EXHIBIT 11 May Creek Channel Restoration Project King County Water and Land Resources Division Wetland Delineation~oa.,o . annmgD" n IlilSion AUG ~ 5 ZOn fRl~((;~U~~/t)) Prepared for: King County Department of Parks and Natural Resources Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 . Prepared by: Lindsey Miller, Environmental Engineer Cindy Clark, Environmental Engineer Todd Martin, Environmental Engineer King County Road Services Division Environmental Unit March 10, 2010 I I I I I I I I I' I I I I ., I I I I I Table of Contents Executive Summary ............................................................................................................ 3 I Introduction ................................................................................................................. 4 1.1 Study Objectives ................................................................................................. 4 1.2 Study Area .......................................................................................................... 4 2 Methods ....................................................................................................................... 6 2.1 Existing Literature Review ................................................................................. 6 2.2 Wetland Classification ........................................................................................ 6 2.3 Wetland Rating ................................................................................................... 7 2.4 Wetland Buffers .................................................................................................. 7 2.S Delineation Methods ............................................... : ........................................... 7 3 Wetland Description ................... : ............................................................................. II 3.1 Landscape Setting ............................................................................................. II 3.2 Hydrology ......................................................................................................... 12 3.3 Soils ................................................................................................................... 13 3.4 Vegetation ......................................................................................................... 14 3.S Wetland Rating ................................................................................................. 16 3.6 Wetland Buffer .................................................................................................. 17 3.7 Wetland Mitigation Ratios ............. ; .................................................................. 17 References ......................................................................................................................... 24 Appendix A -Wetland Rating Form ....................................................................... : ........ 26 Appendix B -Wetland Delineation Data Forms .............................................................. 27 Appendix C -Wetland Photos .......................................................................................... 28 List of Figures Figure I-I: May Valley Vicinity Map ............................................................................... S Figure 3-1: May Valley Wetland Delineation in East Study Area ................................... 19 Figure 3-2: May Valley Wetland Delineation in West Study Area .................................. 20 Figure 3-3: NRCS Soil Survey Map of May Valley ......................................... : ............... 21 Figure 3-4: National Wetland Inventory (NWI) Map of May Valley .............................. 22 Figure 3-S: USGS Topographic Map of May Valley ....................................................... 23 List of Tables Table 3-1: Wetland Vegetation Identified in May Creek #S .............. ; ............................ IS Table 3-2: Mitigation Ratios for Category II Wetlands in King County (KCC 21A.24.340) ..................................................................................................... : ................ 18 May Creek Channel Restoration Wetland Delineation 2 March 2010 I I I I I I' I I I I I I I I Executive Summary King County Department of Parks and Natural Resources (DNRP) is proposing to improve flow conditions and fish passage along approximately 1,500 feet of May Creek between River Mile (RM) 4.3 and 4.S in the May Valley located in southeastern King County near the cities of Renton and Newcastle. One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990), is located in the project study area. This wetland is approximately 140 acres in total size, and approximately 25 acres of it is contained in the project study area and was delineated for this report. The purpose of this wetland delineation was to identify the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. Wetland area was delineated on multiple site visits using the definitions, methods, and standards established in Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineer 200S) and the Washington State Wetlands Identification and Delineation Manual (WDOE 1997). May Creek #5 is a Category II riverine wetland with a 110 foot buffer, located in the natural 1 ~O-year floodplain of May Creek. While the wetland still received a high rating, it has been degraded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. On the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side of the wetland, the wetland boundary more closely follows the natural valley topography. The hydrology source to the wetland is a combination of overbank flooding from May Creek and a high groundwater table. Numerous groundwater seeps were identified on the valley walls. The wetland is primarily palustrine emergent with some scrub- shrub/forested components that are concentrated near May Creek. The vegetation in this wetland has been degraded by the adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing, and therefore contain pasture grasses that could not be accurately identified given the season (late January) and regular mowing. In a majority of the wetland areas not regularly mowed, the dominant vegetation was reed canarygrass (Phalaris arundinacea), which grew in thick blankets with almost 100 percent coverage. The only unmowed areas without reed canarygrass were in the scrub-shrub/forested components of the wetland where the reed canarygrass was shaded out. This wetland, while fairly degraded due to adjacent land use practices, still received a Category II rating due to its high flood storage potential and opportunity, high opportunity to improve water quality, and its moderate potential to provide habitat to a variety of species. Any impacts to this wetland (permanent or temporary) resulting from this project will require mitigation as defined in the King County Critical Area Code (21 A.24.340). Those impacts will be quantified later in the project design process in a separate report. May Creek Channel Restoration Wetland Delineation 3 March 2010 1 Introduction King County Department of Parks and Natural Resources (DNRP) is proposing to improve flow conditions and fish passage along approximately 1,500 feet of May Creek between River Mile (RM) 4.3 and 4.9 in the May Valley (Sections 2 and 3, Township 23N, Range 5E) located in southeastern King County near the cities of Renton and Newcastle (Figure I-I). Active horse pastures and farmland adjacent to May Creek are seasonally flooded and unusable due partially to ineffective flow capacity in this reach of May Creek. The reach of stream being investigated for potential improvement begins on the south side'ofSE May Valley Road approximately 0.1 mile downstream of 14Sth Avenue SE in Renton and includes the main stem of May Creek extending approximately 3,200 feet to a point just upstream from the confluence of May Creek with Indian Meadow Creek. Any project activities proposed in the stream will be completed in coordination with the adjacent property owners. One large riverine wetland, May Creek #5, is located in the study area, and is described in this report. 1.1 Study Objectives The purpose of this wetland delineation was to identify the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. Wetland area was identified and flagged during multiple sites visits using the definitions, methods, and standards established in Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineer 200S) and the Washington State Wetlands Identification and Delineation Manual (WDOE 1997). This study was undertaken to meet permitting requirements for the U.S. Army Corps of Engineers (Corps), Washington State . Department of Ecology (Ecology), and King County Department of Development and Environmental Services (ODES). 1.2 Study Area The study area is located in the Cedar River -Lake Washington Watershed, Water Resource Inventory Area (WRIA) S. The study area includes the properties on the north and south sides of May Creek starting approximately 0.1 mile downstream of 14Sth Avenue SE (RM 4.3) and continuing upstream to approximately RM 4.9 (Figure I-I). The wetland described in this report continues to the east and west outside of the project study area and is identified as May Creek #5 in the King County Wetland Inventory (King County 1990). According to the King County Wetland Inventory, the entire wetland is approximately 140 acres. The full 140 acre wetland boundary was not delineated as part of this study. The boundary was delineated only in the area where potential impacts may occur from the proposed project activities. May Creek Channel Restoration Wetland Delineation 4 March 2010 'I ,. I I I I I I. I I '1 I I I I I I I I ure 1-1: Ma Creek Channel Restoration Project Vicini Legend • Study Area Limits City Boundaries o River Miles Marcil 08, 2010 ---------- , 450225 0 450 900 1,350 1,800 Feet - - ---- ThIt infoo'rNoIon included on ... IMP '-bewI coonPIed ~ King County I&8ft'ffom'......ey d _ WId .. ~ 10 dlrv-wilhoul~. King County mMIol no ~ or ____ . ea\QI'_ Ot~ied, MIOar.:euracy.~.~. orl9>ti 1O"llMoI...c:n~IIOr'I. Thf; ~. not 1I'IIIII'od«l 1ot ...... ......,. procb:l. King County .... no! be .... far.",....., ..... lr'Idir.t.iroodIo"....or~~inc:tUdM'ID.boA IIIIlIir!*d 10. loa __ or k* proIb _ling from .. l.eor_d"'~ODI-.cI an"'INp. ""' .... d .. ....,or~lIOnanthoilll"'fl.~ ... lIywrtlln ~ DfKircl c.c...w.y U1 KIng County -----,---- I I I I I I I I I I I I I I I I I I I 2 Methods The methods used to delineate and characterize the May Creek #5 wetland are described in this chapter. 2.1 Existing Literature Review Prior to visiting the wetland site, ecologists carried out a review of relevant literature, surveys, studies and other works encompassing the cultural and ecological characteristics of the project vicinity and the wetland. Findings from historical topographic maps, aerial photographs, and other documents were incorporated into this report. The following existing documentation was reviewed as part of this study: • May Creek Basin Action Plan (King County 2001) • May Creek Drainage and Restoration Plan (GeoEngineers Inc. 2008) • May Creek Erosion Stabilization Draft Report-May Creek Sediment Transport Study Phase 3 (Anchor QEA LLC 20 I 0) • King County Wetland Inventory (1990) ~ Washington State Dep<\rtment of Natural Resources Natural Heritage Program (2009) • U.S. Geologic Service (USGS) Topographic maps (1921) • U.S. Department of Agriculture (USDA) National Resources Conservation Service (NRCS) Web Soil Survey for King County (2009) • U.S. Fish and Wildlife Service National Wetland Inventory (USFWS 2010a) 2.2 Wetland Classification Wetlands were classified using both the u.S. Fish and Wildlife Service (USFWS) Cowardin habitats (Cowardin et al. 1979), and Washington State's hydrogeomorphic systems (Brinson 1993 and Hruby et al. 1999). . 2.2.1 USFWS Cowardin Classification The USFWS Cowardin classification system (Cowardin et al. 1979) was developed as part of the National Wetlands Inventory (NWI) and used aerial photographs to identifY and map wetlands to the greatest extent possible. This classification system identifies, gathers, and summarizes information on hydrologic, geomorphic, chemical and biological wetland characteristics. Specifically, water flow, water chemistry, substrate types, vegetation types, and dominant plant species are identified and characterized. Wetlands and their habitats are then classified based on the system (palustrine or estuarine, etc.), class (dominant life fOITn of vegetation or physiography and composition ofthe substrate) and by the dominant vegetation stratum and physiographic modifiers present (Cowardin et al. 1979). 2.2.2 Hydrogeomorphic (HGM) Classification The hydrogeomorphic (HGM) classification system (Brinson 1993 and Hruby et al. 1999) identifies and stratifies wetlands into hierarchical classes according to their differences or similarities in wetland functions (Brinson 1993). The HGM classification system complements the USFWS Cowardian system by identifying and categorizing wetlands based on their geomorphic setting (e.g., position of the wetland in the landscape), the source of water for the wetland (e.g., river, lake), and on the flow and fluctuation of the water in the wetland (e.g., hydrodynamics). 2.3 Wetland Rating The wetland within the project area was first characterized by its HGM class and then rated by the degree of hydrologic service, water quality enhancement, and habitat functions it provides using the wetland rating criteria referenced in the King County Critical Area Code (KCC 21A.318). King County adopts the Washington State's Department of Ecology: Washington State Wetland Rating System for Western Washington (Hruby 2004). In King County, wetlands are classified into Category I through IV based on the combination of each wetland's HGM class, rarity and sensitivity, and the cumulative point scores of specific, actual and/or potential, physiobiological functions they may provide based on the wetland characteristics and its surrounding landscape context. Category I wetlands provide the highest wetland function and are difficult to replace, while Category IV wetlands are degraded and disturbed wetlands providing limited function. The completed wetland rating form for May Creek #5 can be found in Appendix A. 2.4 Wetland Buffers A fixed buffer width was subsequently assigned to the wetland based on the wetland's score in the rating system as defined in the King County Critical Area'Code (KCC 2IA.24.325). These buffer widths are further modified based on the wetland's location with respect to the Urban Growth Boundary, habitat functions performed, and the intensity of disturbance from adjacent land use (KCC 21A.24.325). Buffer widths are measured horizontally from the edge of the wetland boundary. Although King County Code stipulates specific fixed buffer widths, the code also allows incremental variations, buffer averaging and other variances from fixed standards based on site-specific features' or the type of action anticipated. King County DOES is responsible for officially implementing the required buffer protection and/or approving variances from fixed widths. 2.5 Delineation Methods King County ecologists visited the project site on five separate days (January 21, 26, and 28,2010, February 24, 2010 and March 1,2010) to delineate the wetland described in this report. They used the guidance provided in the Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineer 2008) and the Washington State Wetlands Identification and Delineation Manual (WDOE 1997) to delineate and characterize the wetland. Potential wetlands were first identified on the dominance of hydrophytic vegetation and both surface and subsurface hydrology. Then, a more detailed analysis of hydrology, soil, and vegetation were performed to confirm the presence of the wetland and its boundary. This analysis is described in more detail later in this section. May Creek Channel Restoration Wetland Delineation 7 March 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I The infonnation collected during these investigations was recorded on the Wetland Detennination Data Fonn from the Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Anny Corps of Engineer 2008). Completed data fonns are attached in Appendix B. Based on infonnation from the three wetland field indicators (hydrology, soils, and vegetation), the boundaries of the wetland were flagged in the field (when possible) and the flag locations were recorded with a GPS unit (Trimble GeoXT Explorer). It was not possible to hang flags along the entire wetland boundary because some wetland areas extended into pastures with active horse use. When it was possible to enter a horse pasture, the GPS unit was used to note the wetland boundary points but no flags were hung. 2.5.1 Hydrology Pennanent or periodic inundation (where soil is saturated within the rooting zone at least seasonally) is the hydrologic force behind wetland fonnation. The presence of water for 12.5 percent or more of the growing season typically creates an anaerobic condition in the soil, which affects the types of plants that grow and the types of soils that develop (WDOE 1997). Hydrological characteristics of the area were assessed to detennine the hydrologic control (i.e., the detenninants of inflow and outflow of water to and from the area) and the capability of the area to pond surface water. The presence of surface water, depth to groundwater, and depth to saturation was recorded at each soil pit location and can be found in the data fonns in Appendix B. Other indicators of wetland hydrology included signs oflengthy inundation, unique drainage patterns, drift lines, watennarks on vegetation and other structures, sediment deposits, water-stained leaves, and hydrophytic vegetation (i.e., plants with morphological adaptations [e.g., adventitious roots] for survival in saturated soils). 2.5.2 Soil Hydric soils are defined as soils that are flooded, ponded, or saturated long enough during the growing season to develop anaerobic conditions in the upper part of the soil profile (WDOE 1997). Anaerobic conditions are created when flooding, ponding, or saturation is of sufficient duration to result in the absence of oxygen. These soils usually support hydrophytic vegetation. A common indicator of hydric soil in this part of Washington is a "Depleted [Gray] Matrix" (U .S. Anny Corps of Engineer, 2008). Hydric soil meeting this criteria must have a layer at least 6 inches thick starting within 10 inches of the mineral soil surface, and that has a depleted matrix with at least 60 percent of that layer having a chroma less than or equal to 2. Soil pits were dug in representative locations throughout the wetland to characterize the soil and to detennine the presence of hydric soil which helped identify the wetland boundary. The soil pits were dug to at least 18 inches in depth and the characteristics May Creek Channel Restoration Wetland Delineation 8 March 2010 were recorded on the data forms found in Appendix B. Soil auger holes, typically dug to at least 16 inches, were used in between soil pits to help establish the presence or absence of hydric soil indicators and to help identify or confirm wetland boundaries. Soil auger holes were also used in the pasture areas with active horse use, where large soil pits were not permitted. The soil profile was described using the standard USDA NRCS Soil Conservation Service (1981) system. Soil texture and color was described using Munsell Soil Color charts assessed for hydric condition (Munsell 2009). 2.5.3 Vegetation Hydrophytic vegetation is defined as plant life growing in water or soil, or on a substrate that is at least periodically deficient in oxygen as a result of excessive water content (WDOE 1997). Vascular plants can be classified in five groups according to the plant's affinity for wetland areas (Reed 1988). These groups are described as follows: • Obligate Wetland (08L): Occur almost always (estimated probability> 99 percent) under natural conditions in wetlands. ~ Facultative Wetland (FACW): Usually occur in wetlands (estimated probability 67 to 99 percent), but occasionally found in nonwetlands. • Facultative (FAC): Equally likely to occur in wetlands and nonwetlands (estimated probability 34 to 66 percent). • Facultative Upland (FACU): Usually occur in nonwetlands (estimated probability 67 to 99 percent), but occasionally found in wetlands (estimated probability I to 33 percent). • Obligate Upland (UPL): Occur in wetlands in another region, but occur almost always (estimated probability < 99 percent) under natural conditions in nonwetlands in the region specified. An area has hydrophytic vegetation when more than 50 percent of the dominant species from all strata are OBL, FACW, and/or FAC species, which are on lists of plant species that occur in wetlands. When either all considered species are FAC or the number of species wetter than FAC equals the number of species drier than F AC, the wetland determination is based on soil and hydrology parameters. Other indicators of hydrophytic vegetation can also be considered in difficult situations. These include observed morphological adaptations of plants to an inundated or flooded environment or review of technical literature. The dominance and locations of hydrophytic vegetation assisted in delineating the wetland boundaries. Vegetation plots were created and analyzed at the soil test pit locations and the vegetation at these locations was recorded on the data forms in Appendix B. The common and scientific plant names and indicator status (OBL, FACW, May Creek Channel Restoration Wetland Delineation 9 March 2010 I I I I I I I I I I I I I I I I ,. I I ,---c----------------------------------- I I I I I I I I I I I I I I I I I I I etc.) used in this report are consistent with A Field Guide to the Common Wetland Plants a/Western Washington and Northwestern Oregon (Cooke et al. 1997) unless updated by other works as noted. May Creek Channel Restoration Wetland Delineation 10 March 2010 3 Wetland Description This section describes the existing conditions of the wetland located in May Valley, referred to as May Creek #5 in the King County Wetland Inventory (1990). The King County Wetland Inventory indicates that this wetland is approximately 140 acres. Approximately 25 acres of this wetland are contained within the project study area. 3.1 Landscape Setting May Creek #5 is a riverine wetland located in the mapped 100-year floodplain of May Creek (WRIA Stream #08.0282). May Creek is a 7-mile stream in the Lake Washington Watershed (WRIA 8). The stream originates in the steep forested slopes of Cougar and Squak Mountains, and flows northwesterly eventually draining into the southern portion of Lake Washington. In the project study area May Creek flows through May Valley, a natural floodplain that has historically been prone to flooding. The May Creek #5 wetland covers the majority of the May Valley. According to the May Creek Current and Future Conditions Report (King County 1995) May Creek has been channelized and dredged throughout the May Valley since at least 1936. King County continued to dredge May Valley in the 1940's and deposited the material onto the surrounding properties. This dredging reduced the duration and extent of flooding in the May Valley and allowed property owners to use the land for agriculture and grazing livestock. Regular dredging appears to have ceased sometime after the 1940's due to increasing protection of sensitive areas. Today, the majority of the properties in the May Valley are rural residential with active agriculture and grazing; however, the lack of dredging activities over the last 50 years means that May Valley is once again experiencing prolonged periods of flooding during the wet season. This flooding limits the amount of area that residents can use for agriculture and·grazing. During the wet season, horses and other livestock are either moved to areas located on the higher valley slopes or to areas that appear to have been raised out of the floodplain (over many years) with fill. While the current extent of the flooding limits horse pasture use, it is likely that it is closer to natural historical conditions pre-development. In the northeast quadrant of the study area, where farm use is the most pronounced, the wetland boundary closely follows the fence line associated with the horse pastures. Over the years, fill appears to have been placed in the wetland to increase usable farm area. The wetland boundary in the southeast quadrant of the study area is also located in horse pastures, but more closely follows the natural valley topography (Figure 3-1). In the undeveloped area in the northwest quadrant of the study area, the wetland boundary extends into the scrub-shrub/forested areas located at the toe of the valley wall, with one exception; In the most northwestern quadrant of the study area it appears that fill was placed in the wetland many years ago to accommodate a home that no longer exists (Figure 3-2). Remnants of the old buildings can be seen in this area. \ The wetland boundary in the undeveloped areas in the southwestern quadrant of the study area, closely follows the topography and is easily visible by a change in vegetation (reed May Creek Channel Restoration Wetland Delineation 11 March 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I canarygrass (Pha/aris anmdinacea) to Himalayan blackbeny (Rubus procerus). In a small area directly west side of I48th Avenue NE it appears that fill was placed in the wetland. The boundary in this area is irregular (it does not follow the natural topography) and is demarcated by large patches of scotch broom (Cytisus scoparius) and an unknown pasture grass (Figure 3-2). 3.2 Hydrology The primary source of hydrology to the May Creek #5 wetland is a combination of overbank flooding and a high groundwater table. Multiple groundwater seeps were visible on the valley walls at higher elevations. Two tributaries flow south off the northern hillside and one tributary flows north from the southern side of the project area, providing additional sources of hydrology. Many areas ofthis wetland are frequently flooded (at least once every 2 years) by May Creek, and therefore May Creek #5 would be classified as a riverine wetland using HGM system (Hruby 2004). It should be noted that riverine wetlands also commonly receive significant amounts of water from other sources such as groundwater and slope discharges (Hruby 2004) as is the case in the May Valley. A wetland hydroperiod is the period of time during which the wetland is covered by water. Hydroperiods in this wetland include areas that are seasonally flooded and areas that appear to be only occasionally flooded at higher elevations. At even higher elevations along the valley walls, soil is saturated and hydrology is driven by primarily groundwater seeps. Overbank flooding in these higher areas is limited. Wetland Soil Pit #1 (Figure 3-2) was located on the south side of May Creek on the east side of l48th Avenue SE approximately 35 feet from the stream. Indicators of hydrology at this location included visible observation of surface water (within 10 feet of the soil pit) high water table (present at 8 inches below the surface), soil saturated to the surface, water marks, and water stained leaves. Based on the strong hydrology indicators at this location, it was assumed that hydrology would be present at this location and in locations at a similar elevation throughout the growing season. Wetland Soil Pit #3 (Figure 3-1) was located on the south side of May Creek on the eastern side of the study area at a higher elevation than the first pit. This area does not appear to receive regular overbank flooding due to its elevation; however other indicators of hydrology included a high water table (present 5.5 inches below the ground surface), and soil saturated to the surface. Groundwater seeps were also identified nearby at similar elevations. Wetland Soil Pit #4 (Figure 3-2) was located on the north side of May Creek on the east side of l48th Avenue SE. Indicators of hydrology in this area included a high water table (present 4.5 inches below the ground surface), soil saturation to the surface, water marks, algal mat, water-stained leaves, a hydrogen sulfide odor, and oxidized rhizospheres along living roots. May Creek Channel Restoration Wetland Delineation 12 March 2010 Wetland Soil Pit #6 (Figure 3-2) was located on the north side of May Creek and on the west side of 148th Avenue SE. This area is probably too far from the stream to receive regular overbank flooding, but indicators of hydrology in this location include a high water table (present 9 inches below the ground surface) and soil saturated to the surface. Wetland Soil Pit #7 (Figure 3-2) was located on the south side of May Creek and on the west side of 148th Avenue SE. This area probably receives overbank flooding from May Creek during annual storm events. Indicators of hydrology on the field day included a high water table (present 12 inches below the surface) and saturated soil to the surface. A soil pit was not dug in the northeastern quadrant of the study area because the wetland area extended into active horse pastures (Figure 3-1). In these· areas hydrology indicators included visual observation of surface water (seeps), water marks, water stained leaves, and a high water table that was observable using a soil auger. Upland Soil Pits #2 and #S (Figure 3-2), near Wetland Soil Pits #1 and #S respectively, did not contain any hydrology indicators. The water table was not present at 18 inches below the surface, and the soil was not saturated. 3.3 Soils The NRCS Web Soil Survey (2009) indicates that Beliingham silty loam (Bh) is found at the lower elevations in the May Valley (Figure 3-3). The Ragnar-Indianola association (RdC) is found on the higher elevations on the south side ofthe May Valley, and Alderwood gravelly sandy loam (AgC and AgO) is found on the north side of May . Valley. Alderwood gravelly sand loam (AgC) and Bellingham silty loam (Bh) are both on the NRCS hydric soil list for Washington State. Field visits confirmed the presence of these hydric soils in the May Valley. In addition, the field visits found a thick layer of clay in the western half ofthe study area. Wetland Soil Pit #1 contained one uniform soil horizon from 0 to 18 inches below the surface. The soil was a black clay (I OYR 2/1) with redoximorphic (redox) features (soil mottling) that were too small to color. Redox features are soil properties, associated with wetness, which results from the reduction and oxidation of iron and manganese compounds in the soil after water saturation and desaturation, respectively. Soil mottles are commonly identified redox features. The redox features were concentrations covering about I percent of the matrix. This soil meets the criteria F3 for hydric soil (depleted matrix with a layer at least 6 inches thick starting within 10 inches of the mineral soil surface). Wetland Soil Pit #3 contained three soil horizons. The first horizon (from 0 to 6.S inches) was a black loamy sand (SYR 2.S/I) without redox features. This soil meets the criteria F3 for hydric soil (depleted matrix with a layer at least 6 inches thick starting with 10 inches of the mineral soil surface). The second horizon (from 6.S to 11.S inches) was a yellowish brown silty loam (lOYR S/4) with redox features in approximately 10 percent of the matrix. The third horizon (l1.S inches to 18 inches) was a dark yellowish brown silty loam (IOYR 4/6) without any redox features. The second two horizons did not meet May Creek Channel Restoration Wetland Delineation 13 March 2010 I I I I I I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I the criteria for hydric soil; however, since the first horizon met the criteria for hydric soil, this sampled area was determined to be inside the wetland. Wetland Soil Pit #4 also contained three soil horizons. The first horizon (0 to 8.5 inches) was a black clay (10 YR 2/1) without any redox features. The second horizon (8.5 to 13.5 inches) was also a black clay (2.5 YR 2.5/1) with 50 percent coverage of redox features. The third horizon (13.5 to 18 inches) was again a black clay (lOYR 2/1) without any redox features. This soil meets the criteria F3 for hydric soil (depleted matrix with a layer at least 6 inches thick starting with 10 inches of the mineral soil surface). Wetland Soil Pit #6 contained two soil horizons. The first horizon (0 to 5 inches) was the same black clay (10 YR 211) without redox features that was observed in Soil Pit #4. The second horizon (5 to 18 inches) was the same black clay but it contained faint redox feature in about 20 percent of the matrix. This soil meets the criteria F3 for hydric soil (depleted matrix with a layer at least 6 inches thick starting with 10 inches of the mineral soil surface). Wetland Soil Pit #7 had a two inch dufflayer that was followed by one uniform horizon (2 to 18 inches). This horizon was a very dark grayish brown (I OYR 3/2) clay layer with yellowish red redox features (5 YR 5/8) in 20 percent of the matrix. This soil meets the criteria F3 for hydric soil (depleted matrix with a layer at least 6 inches thick starting with 10 inches ofthe mineral soil surface). Soil pits were not dug in the northeastern quadrant of the study area because the wetland area extended into active horse pastures. In these areas, the soil was sampled using a soil auger and examined for hydric indicators. The soil in this area had similar characteristics as what was recorded for Soil Pit #3 .. Upland Soil Pits #2 and #5, near Wetland Soil Pits #1 and #5 respectively, did not.contain any indicators of hydric soil. The soil chroma (3 and 4) was too high to meet the criteria for a depleted matrix, and the soil did not exhibit any other hydric indictors. 3.4 Vegetation According to the NWI, May Creek #5 is a palustrine wetland with primarily emergent vegetation. This is consistent with what was found in the field; however, in addition, many portions ofthe wetland immediately adjacent to May Creek also contain a scrub- shrub vegetation component. A smaller portion of the wetland could be considered forested (Figure 3-4). The vegetation in this wetland has been degraded by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing, and therefore contain pasture grasses that could not be accurately identified given the season (late January) and regular mowing. In a majority of the wetland areas not regularly mowed, the dominant vegetation was reed canarygrass which grew thick blankets with almost 100 percent coverage. On the western side of the wetland, hardhack (Spirea doug/asii) out- May Creek Channel Restoration Wetland Delineation 14 March 20.10 competed the reed canarygrass is some areas. The only unmowed areas without reed canary grass were in the scrub-shrub/forested components of the wetland where the reed canarygrass was shaded out. The dominant vegetation in the scrub-shrub/forested portions of the wetland were willow species (Salix spp.), red alder (Alnus rubra), and Oregon ash (Fraxinus lalifolia). A portion of the scrub-shrub vegetation along May Creek was planted in the past 10 years by King County DNRP to improve riparian coverage and shade out the reed canarygrass. A complete list of the vegetation identified in the wetland is shown in Table 3-1 with its Latin name, common name, wetland indicator status, and whether or not it was a dominate species in any of the areas surveyed. A species was considered dominant if it had at least 20 percent absolute coverage within its stratum. T bl 3 1 W tl d V t f Id ff d' M C k #5 a e -e an ege a Ion en lie In ay ree Latin Name Common Name Dominant Herb Stratum Carex obnupla slough sedge No Equisetum telmateia giant horsetail No Juncus effusus soft rush Yes Lysichitum americananum skunk cabbage No Phalaris arundinacea reed canarygrass Yes Polyslichum munitum sword fern No Ranunculus repens creeping buttercup No unknown moss Yes unknown various pasture grasses Yes ShrubNine Stratum .. Amelanchier alnifolia Saskatoon serviceberry Yes Cornus sericea red-osier dogwood No Oemleria cerasiformis Indian plum Yes Physocarpus capitatus Pacific ninebark No Rosa pisocarpa peafrui t rose Yes Rubus procerus Himalayan blackberry Yes Rubus speclabilis Salmonberry Yes Salix hookeriana Hooker's willow Yes Salix lasiandra Pacific willow Yes Salix scouleriana Scouler's willow Yes Salix sitchensis sitka willow Yes Spirea douf;!lasii hardhack Yes Svmphoricarpos albus snowberrv No Tree Stratum Alnus rubra red alder Yes Fraxinus latifolia Oregon ash Yes Picea silchensis Sitka spruce No Prunus spp. Cherry Yes Pseudotsuf;!a menziesii Douglas fir Yes Thuia plic/ala Western red cedar Yes unknown ornamental fruit trees No "Identifies a tentative assIgnment based on confhctmg revIews May Creek Channel Restoration Wetland Delineation 15 .' Indicator Status . . . OBL FACW FACW OBL FACW FACU FACW unknown unknown .' FACU FACW FACU FACW FAC FACU FAC FACW FACW FAC FACW FACW FACU .. FAC FACW FAC FACU FACU" FAC unknown March 2010 I I I I I I I I I I' I I I I I I I I I I I I I I I I I I I I I I' I I I I I I Upland vegetation in the wetland buffer included ornamental maple (Acer sp.), Indian plum (Oemleria cerasiformis), beaked hazelnut (Corylus cornuta), unknown fruit trees, Himalayan blackberry, sword fern (Polystichum munitum), bracken fern (Pteridium aquilinum), tall fescue (Festuca arundinacea), orchard grass (Datctylis glomerata), bentgrass (Agrostis sp.), scotch broom, and unknown thistle species. 3.5 Wetland Rating The wetland in the study area was rated as one unit using the Washington State Wetland Rating System/or Western Washington (Hruby 2004). According to the guidance in the rating system, when a stream that is less than 50 feet wide bisects a contiguous vegetated wetland, wetland area on both sides of the stream should be treated as a single unit (Hruby 2004). Additionally, even though the wetland is divided by 148th Avenue SE, the wetland was not divided into separate units for the purposes of the rating system because there is a level surface-water connection (May Creek) between the two parts of the wetland (Hruby 2004). Under the Washington State Wetland Rating System/or Western Washington, May Creek #5 is a Category II riverine wetland scoring 61 out of 100 points (Appendix A). The wetland provides moderate water quality function (scoring 14 points). The wetland has high opportunity to improve water quality due to the close proximity of grazing, roadways, and residential development; however, its potential to improve water quality is only moderate due to a lack of un grazed herbaceous vegetation and trees/shrubs in the wetland. The wetland provides high hydrologic function (scoring 26 points). The wetland has the opportunity to reduce flooding and erosion due to the roads and bridges downstream, as well as potential salmon habitat. In addition, due to the large amount of available flood storage it also has a high potential to reduce flooding and erosion. The wetland provides moderate habitat function (scoring 21 points). The wetland has high potential to provide habitat for many species because it is large enough (over 140 acres) to contain mUltiple vegetation classes, hydroperiods, and a richness of plant species. On the other hand, the opportunity that this wetland has to provide habitat is limited due to disturbed buffers and active grazing adjacent to much of the wetland, as well as disturbed connections to other vegetated corridors or wetlands. Wildlife observations in the study area during the wetland survey included over 25 species of birds, including great blue heron (Ardea herodias) and red-tailed hawk (Buteo jamaicensis), as well as Columbia black-tailed deer (Odocoileus hemionus columbianus), raccoon (Procyon lotor) and coyote (Canis latrans). This wetland rating is preliminary and should not be considered final until King County DOES has reviewed and approved this report. May Creek Channel Restoration Wetland Delineation 16 March 2010 3.6 Wetland Buffer The buffer for this wetland would be liD feet according King County Code 21A.24.325. The wetland buffer is determined by using the wetland rating (Category II), in conjunction with the wetland habitat score (21 points), and the adjacent land use (moderate impact). Moderate adjacent impact land use is assumed due to agricultural use on some of the adjacent properties without an approved farm management plan. Two of the farms adjacent to the wetland have farm management plans, but the other farms and properties do not. In addition, the majority of the wetland buffer contains paved areas, buildings, and pastures. These areas provide limited wetland buffer function. This wetland buffer is preliminary should not be considered final until King County DOES has reviewed and approved this report. 3.7 Wetland Mitigation Ratios King County Code 21 A.24.340 defines mitigation replacement ratios to compensate for adverse effects to a wetland or its buffer. The mitigation replacement ratio is based on the wetland category of the impacted wetland and the type of mitigation proposed to compensate for the impact. King County Code also adjusts mitigation replacement ratios based on the type of impact (permanent or temporary). A permanent impact would be placing permanent fill in the wetland or permanently dewatering a portion of wetland. A temporary impact would be conversion of a scrub-shrub/forested wetland to an emergent wetland, or temporary vegetation removal associated with construction activities. Alterations to a wetland buffer require compensation at a simple I: I ratio (i.e., I acre of mitigation for every I acre of impact). Table 3-2 summarizes the mitigation replacement ratios for Category II wetlands according to King County Code 2IA.24.340. The impacts resulting from the project activities, as well as any required mitigation will be analyzed in a separate report. May Creek Channel Restoration Wetland Delineation 17 March 20tO I I I I I I I I I I I I '1 I I I I I I I I I I I I I I I I I I I I I I I I I Table 3·2: Mitiaation Ratios for Cateaorv II Wetlands in King County (KCC 21A.24.3401 Impact Type Wetland reestablishment or creation Permanent fill or 3:1 dewatering Conversion of forested/scrub· 1.5:1 shrub to emergent Temporary construction 0.75:1 impacts May Creek Channel Restoration Wetland Delineation Mitigation Type 1:1 Wetland Wetland reestablishment or Wetland rehabilitation wetland creation (RIC) enhancement and wetland only enhancement (E) 8:1 1:1 RIC and 4:1 E 12:1 2:1 N/A 3:1 1 : 1 N/A 1.5:1 18 March 2010 Figure 3-1: May Valley Wetland Delineation in East Study Area Legend • Tribs or Seeps --Streets o Soil Pit Wetland Buffer 110' Wetland • Wetland GPS Points March 08 , 2010 130 65 0 130 260 390 520 Feel --- --- - TN dorTNton inca.dId 001" IMp'" ban ~ try Ki'lgeo..ntyItllll'FI'om.~d_~.-.cI;'~1O d'I.nge 'OIIhout noIic&. King County m.kM IICI ~1IilIIII'tI or -.r. ..... __ orimplied •• lo 8CICUfKlI.~, ........ III' I!IP* 10 ". u_ 01 auc:h .. '-lion n.~.I'IOt....-.:l"b ...... .......,.pI'OIt.ocl. King Caunty .... no!: be .... Ior ...,. gINtIIII. ~. inchct.~.or~~irQJdong, boA nail ~ 10, me __ ..... prc*I; _Me 110m It. _or_oI".~cor-...dOl'l""', ktfA'-d"""pOlon~on~lIIIC).pt'IItoibUd UOIpI t.,1fIIriI .. ~ oIKinQCClUnIy ti KkIg County ------------------- - Figure 3-2: May Valley Wetland Delineation in West Study Area Legend • Tribs or Seeps --Streets o Soil Pit Wetland Buffer 110' Wetland • Wetland GPS Points March 08 , 2010 - -- ---- - -- 100 50 0 100 200 300 400 Feet - - ---- - - The""'~ irIc:II.odtd on .. _p tIM ~ c:cmPIed by King Cciunly ..." from • ....-..y ai_"*, .-d it; IUbjtocIIO Cf'I.-.ge without ~, King County ......... no repl1l$8ntabON or warranties, IUpreH Of implied. .. 10 ..:an.c:y. ~, 1imeIiness, or nghls lID Ihe use '" -..ell infarmalian. TIu dco;umIonI iI no! inwoded b 11M _ • ~ pt'CICb:t. King CaJnIy ... noI be ~ lor fn1 gerwwaI . ~. irMIiNCt.~, or ~ dMn8ges indudIng, but not limited 10. "* re __ or "-' profitt ,-,ling ffl)lllh 11M Of mis .... of Chi intormaIion conIIIined 011 this ""p . 1>nt .. 1e oIlh11 ""POI' in~rioI'I on 11'i1"..P;' prot;bQd acep; by~ .. ~ of King ec..nt)'. tQ KIng County - -- -- - - Figure 3-3: NRCS Soil Survey Map of May Valley 310155 0 310 620 930 1,240 Feet -------- March 06 , 2010 N Legend NRCS Soil Survey Soil Types + _ AgC (Alderwood Gravelly Sandy Loam) _ AgO (Alderwood Gravelly Sandy Loam) _ BeD (Beausije Sandy Loam) _ Bh (Bellingham Silt Loam) _ EvB (Everett Gravelly Sandy Loam) _ EvC (Everett Gravelly Sandy Loam) _ OvC (Ovall Gravelly Loam) _ OvO (Ova ll Gravelly Loam) _ RdC (Ra gn a r-Indianola association) n. inIormMiarI inc:IucMd an It-. INP "-bMn ~ try IGrog Coutty .-rfrom_ ....... 'Y d __ 8nd It ~ II:! cn.nge WIIIDut rae. I<ingCclurly",*-no,.~_or~ ~ orft'41litd,.IO-.acy,~""""CII' ngtU II) ,. ~ of IYCtI ontcmw ..... n..~ .. I'd ~ 1Dr ....... ..-..y product. I<ing Coutty .... nat t. WI6Io ... q,..... ...... ndirKl. irodIraI. or CIIfIMqUOtI'IIi '*""'" indudong. but nallimiMod 10.l0iii _ or kilt ~ _Ing &an lie; ... or _oI .. 1IIfarrnIbon ~ 01'1" INP. I>nt ... oI .... n-.p or ~1IIr!Nban on"lMP. protibi'-l aoepI by wn-.n ""..........., 01 KA<Ig COunty UI King County ------------------ Figure 3-4: National Wetland Inventory (NWI ) Map of May Valley 480240 0 480 960 1,440 1,920 Feet - - -- - - Mar ch 08 , 2010 -------- Legend USFWS NWI Wetla nds Classes N + _ PEMAd (Palustrine Emergent Temporarily Flooded Partially Drained) _ PEMC (Palustrine Emergent Seasonally Flooded) PEMCd (Palustrine Emergent Seasonally Flooded Partially Drained) _ PEMF (Palustrine Emergent Semipermanently Flooded) _ PFOC (Palustrine Forested Seasonally Flooded ) _ PFOCd (Palustrine Forested Seasonally Flooded Partially Drained) _ PSSC (Palustrine Scrub-Shrub Seasonally Flooded) _ PSSCd (Palustrine Scrub-Shrub Seasonally Flooded Partially Drained) TheIri'OIINlcIn irdudItd on .. ""*' '* ~ ~ iI1 iring co..., ""'!rom • ....-.t)' af -.rc. wd ;. 8Utijed '" ~...,..-. Ki'ogCaunry"....no, .......... _'IIb;;o_N.or __ ..... ~ Of ompIiad. _ to 1ICiCUrK'y.~ ........ , 01 nghM III .. uN 01 aid'! inbmIlion. n. ~;. not ~td far ...... SU"Ie)' procU:l. King CoutCy IIhIoII no! be hIM kif ." ~.IIj)eCIII. ncnd, 1nadrMI, or oor.equ ..... ~~. but noIlimiMd to , 10M ,....,.".. Of loll proIIa _1Mg from IN .... or __ af III; Wornwbon CCIII'DiwI on ... II'W(t krf .... af .. _p Of ~tiarI on 'I'M INP .. prahitlad __ iI1 "etI .---01 K'Ig COr.onty. ----------- I I I I I I I I I I ~ 9- 0 ? '" ~ 0 • 0 ~ ~ ~ 't 0 ~ ~ "T1 CO· C CD c..v I (]'I -, I I I I I I I I I I I I I I I I I I I References Anchor QEA LLC., 20 I O. May Creek Erosion Stabilization Draft Report -May Creek Sediment Transport Study Phase 3. January 2010. Prepared for King County Department of Parks and Natural Resources. Seattle, Washington. Available online at: http://www.kingcounty.gov/environment/watersheds/cedar-river-Iake- wa/may-creeklerosion-stabilization-report.aspx (Accessed February 2010) Brinson, M. M. 1993. A hydrogeomorphic classification for wetlands. U. S. ArmyCorps of Engineers, Waterways Experiment Station, Vicksburg, MS. Tech. Rep. WRP- DE-4. Brinson, M. M, Hauer, FR., Lee, L. c., Nutter, W. L., Smith, R.D., Whigham, D. 1994. Guidebook for Application of Hydrogeomorphic Assessments to Riverine Wetlands.203pp. Cooke, S. S. ed. 1997. A Field Guide to the Common Wetland Plants of Western Washington and Northwestern Oregon. Seattle Audubon Society Washington Native Plant Society.417 pp. Cowardin, L. M., V. Carter, F.C. Golet and E.T. LaRoe. (1979). Classification of wetlands and deepwater habitat of the United States. Washington D.C., USA, U. S. Fish and Wildlife Service: 103pp. GeoEngineers Inc., 2008. Final Draft May Creek Drainage and Restoration Plan. December 19,2008. Prepared for King County Water and Land Resources Division. Seattle, Washington. Hruby, T, T. Granger, K. Brunner, S. Cooke, K. Dublanica, R. Gersib, L. Reinelt, K. Richter, D. Sheldon, E. Teachout, A. Wald, and F. Weinmann. July 1999. Methods for Assessing Wetland Functions Volume I: Riverine and Depressional Wetlands in the Lowlands of Western Washington. WA State Department Ecology Publication #99-115. Hruby, T. 2004, Washington State wetland rating system for western Washington- Revised. Washington State Department of Ecology Publication # 04-06-025. King County Environmental Division. 1990. King County Wetland Inventory. Department of Parks, Planning, and Resources, King County, Washington. King County and City of Renton. 1995. May Creek Current and Future Conditions . Report. King County Surface Water Management Division and Renton Department of Public Works, August 1995. Seattle, Washington. May Creek Channel Restoration Wetland Delineation 24 March 2010 King County and City of Renton. 200 I. Final Adopted May Creek Basin Action Plan. King County Surface Water Management Division and Renton Department of Public Works, April 2001. Seattle,Washington. Available online at: http://www.kingcounty.gov/environmentlwatersheds/cedar-river,lake-waimay- creeklmay-creek-basin-plan.aspx (accessed February 2010) Munsell Soil Color Charts (2009). (http://www.munsellstore.comiindex.cfmlMenultemID/468IMenuGroup/Home.ht m) Date Accessed 4/20109 Reed, P.B., Jr. 1988. National list of plant species that occur in wetlands: Northwest (Region 9). U.S. Dept. of the Interior, Fish and Wildlife Service. Biological Report 88 (26.9). 89 pp. USFWS (U.S. Fish and Wildlife Service). 2010a. National Wetland Inventory from Wetlands Online mapper located at http://www.fws.gov/wetlandslData/mapper.html( accessed January 2010) USFWS (U.S. Fish and Wildlife Service). 2010b. Wetlands and Deepwater Habitats Classification -National Wetlands Inventory Mapping Code Description. Available online: http://www.fws.gov/wetlands/Data/webatxlatx.html (accessed September 2009) USDA Natural Resources Conservation Service. 2009. Soil Survey of King County, Washington. Version 6, September 22, 2009. Online mapper located at http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm (accessed January 2010) USGS (U.S. Coast and Geodetic Survey) (1900). Washington: Tacoma Quadrangle. March 1900 edition (Surveyed in 1894-1895). Tacoma, WA, USDI -u.s. Geological Survey: Topographic Map. WDOE (Washington Department of Ecology) (1997). Washington State Wetlands Identification and Delineation Manual. Olympia, W A, Department of Ecology: 88 plus Appendices .. DNR (Washington Department of Natural Resources). 2009. Natural Heritage Program Wetland Information. July 21, 2009. Olympia, Washington. Available online at: http://wwwl.dnr.wa.gov/nhp/refdeskldatasearchlindex.html (Accessed February 2010) May Creek Channel Restoration Wetland Delineation 25 March 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number WETLAND RATING FORM -WESTERN WASHINGTON Version 2 -Updated july 2006 to increase accuracy and ,'eproducibility alllong usel's Updated Oct 2008 with the new WDFW definitions fol' priority habitats 1/21/z..oI0 ,1/2 b /:J,o/l> Name of wetland (if known): fVl~ Oe.ek 1f 5 Date of site visit: 1/2.8'j..2.<> '0 ,:1/)o.I):J.oto Rated by l-fv1 ,e..e.. I TM Trained by Ecology? Yes_No_ Date oftraining, __ _ SEC:2 ,3TWNSHP:A3N RNGE: 2£.. Is SrrtR in Appendix D? Yes_ No X Map of wetland unit: Figure _1_ Estimated size !,-/O a cr L S SUMMARY OF RATING Category based on FUNCTIONS provided by wetland 1_ IlL III_ IV_. Score for Water Quality Functions / t.f Score for Hydrologic Functions d to Score for Habitat Functions ,?-I r-oi---.I TOTAL score fOl' Functions !o I ....... _ .. Category based on SPECIAL CHARACTERISTICS of wetland 1_ 11_ Does not Apply X Final Category (,b_ th. "'"gh .... ,".g'", lrom ,,,,,,,.) I' [ I None of the above Wetland Rating FOl'm -westem Washington August 2004 vel'sion2 To be used with Ecology Publication 04-06-025 · Wetland name or number __ Does the wetland unit being rated meet any of the, criteria below? I f you answer YES to any of the questions below you will need to protect the wetland according to the regulations regarding the special characteristics found in the wetland. unit as Threatened or Endangered animal species? For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. Note: Wetlands with State listed plant species are as I Natural Wetlands 19 of data SP3. Does the wetland unit contain individuals o.(Priority species listed by the WDFW for the state? SP4. Does the wetland unit have a local significance in addition to its functions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local management plan as having special significance. To complete the next part ofthe data sheet YOU will need to determine the Hvdrogeomorphic Class ofthe wetland being rated. >( The hydrogcomorphic classification groups wetlands into those that function in similar ways. This simplifies the questions needed to answer how well the wetland functions. The Hydrogeomorphic Class of a wetland can be determined using the key below. See p. 24 for more detailed instructions on classifying wetlands. Wetland Rating Fonn -western Washington 2 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 I I I I I I I I I I I I I I I I I I I ,-------------------------------- I I I I I I I I I I I I I I I I I I I Wetland name or number Classification of Wetland Units in Western Washington 1. Are the water levels in the entire unit usually controlled by tides (i.e. except during floods)? & go to 2 YES -the wetland class is Tidal Fringe If yes, is the. salinity of the water during periods of annual low flow below 0.5 ppt (parts pel' thousand)? YES ~ Freshwater Tidal Fringe NO -Saltwater Tidal Fringe (Estuariue) !f your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. Ifit is Saltwater 1Ydal Fringe it is rated as an Estuarine wetland. Wetlands that were called estuarine in the first and second editions of the rating system are called Salt Water Tidal Fringe in the Hydrogeomorphic Classification. Estuarine wetlands were categorized separately in the earlier editions, and this separation is being kept in this revision. To maintain consistency between editions, the IeI'm "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category I and II estuarine wetlands have changed (see p. ). 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water toit. Groundwater and surface water runoff are NOT sources of water to the unit. ~ go to 3 YES -The wetland class is Flats If your wetland can be classified as a "Flats" wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet both ofthe following criteria? _The vegetated paJ1 of the wetland is on the shores ofa body of penn anent open water (without any vegetation on the surface) at least 20 acres (8 ha) in size; _At least 30% of the open water area is deeper than 6.6 ft (2 m)? §-go to 4 YES -The wetland class is Lake-fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following critelia? __ The wetland is on a slope (slope can be very gradual), __ The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks. . __ The water leaves the wetland without being impounded? NOTE: Su~face water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3ji diameter and less than 1 foot deep). ®-go to 5 YES -The wetland class is Slope Wetland Rating Fonn -western Washington 3 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 Wetland name or number 5. Does the entire wetland unit meet all of the following criteria? -2( The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river ~ The overbank flooding occurs at least once every two years. NOTE: The riverine unit can contain depressions that are filled with water when the river is not flooding. NO -go to 6 @-The wetland class is Riverine 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year. This means that any outlet, if present, is higher than the interior of the wetland. NO -go to 7 YES -The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding. The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO -go to 8 YES -The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM clases. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS \-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within your wetland. NOTE: Use this table only if the class that is recommendcd in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. as wetland wetlands with special I I I I I I I I I I I I I I I If you are unable still to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional I for the rating. Wetland Rating Foml-westen! Washington 4 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 I I I I I I I I I I I I I I' I I I I I I I I Wetland name or number D D D D D D 1. Does the wetland unit have the potential to impt'ove water quality? D 1.1 water the wetland: Unit is a depression with no surface water leaving it (no outlet) points = 3 Unit has an intermittently flowing, OR highly constricted permanently flowing outlet points = 2 Unit has an Ul1collstricted, or slightly constricted. surface outlet (permanently flowing) points = I Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanelll surface outflow alld 110 obvious 1IatufIli outlet and/or outlet is a man·made ditch points = 1 ar (litch is no/ permanently flowing treal unit (/s "iniermitlelllly flowing ") definitions) YES NO below the persistent Wetland has perSistent, ungrazed, vegetation> = 95% of area Wetland has persistent, ungrazed, vegetation> = 1/2 of area Wetland has persistent, ungrazed vegetation> = \/10 of area Wetland has persistent, ungrazed vegetation <\11 0 of area Cowardin D 1.4 Characteristics of seasonal ponding or inundation. points = 5 points = 3 points = 1 points = 0 classes 11l1s is the area of the weiland unit that is ponded for at least 2 months, but dries out sometime during the year. Do not count the area that is permanently ponded. Estimate area as the average condition 5 out of J 0 yrs. Area seasonally ponded is > y, total area of wetland Area seasonally ponded is> \Ii total area of wetland Area seasonally ponded is < \Ii total area of wetland points = 4 points = 2 points = 0 (seep,38) ~------------------~~~~~------Total (01' Dl Add the points in the boxes above D ~---r~~=---~----~----~----~--------~----~------------~~~-----------i~----D D 2. Does the wetland unit have the opportunity to improve water quality? (see p. 44) D Answer YES if you know 01' believe there are pollutants in groundwater 01' surface water coming into the wetland that would othelwise reduce water quality in streams, lakes or groundwater downgradient from the wetland. Note which of the following conditions provide the sources ofpollut(rnts. A unit may have pollutants comingfrom several sources, bUI (my single source would qualijyas opportunity. Grazing in the weiland or within I SO ft Untreated storm water discharges to wetland Tilled fields or orchards within 150 ft of wetland A stream or CUlVC11 discharges inlo wetland that drains developed areas, residential areas, farmed fields, roads, or c!ear·cullogging Residential, urban areas, golf courses are within 1 SO ft of wetland multiplier Wetland is fed by groundwater high in phosphorus or nitrogen Other YES NO is 1 TOTAL -Watel' Qnality Fnnctions Multiply the score from D1 by D2 Add Wetland Rating Form -weslcl'I1 Washington 5 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 .' Wetland name or number D D D water out unit Unit is a depression with no surface water leaving it (no outlet) points = 4 Unit has an intermittently flowing, OR highly constricted permanently flowing outlet points = 2 Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanent surface outflow and no obvious natural, outlet and/or outlet is a man-made ditch points = I (If ditch is nol permanenl(v freat unit as "inlel'millenl()I. ") Unit has an surface = 0 D 3,2 Depth of storage wet Estimate the height ofponding above the bottom oflile outlet. For units with no ollllet measure from the sUijace'ofpermanent water or deepest part (if dlY). Marks of ponding are 3 ft or more above the surface or bottom of outlet points = 7 The wetland is a "headwater" wetland" points = 5 Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet points = 5 Marks are at least 0.5 ft to < 2 ft from surface or bottom of outlet points = 3 Unit is flat (yes to Q. 2 or Q. 7 on key) but has small depressions on the surface that trap water points = I Marks less than 0.5 ft = 0 to storage Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself ' The area of the basin is less than 10 times the area of unit points = 5 The area of the basin is IOta 100 times the area of the unit points = 3 The area of the basin is more than 100 times the area of the unit points = 0 Entire unit FLATS ~~~~~~~~~~~~~~-------~----------~~--~~~~-I .... ------ Total for D 3 Add the pOints ill the boxes above D ~~~~~~--~------~--~--------------------------~------------~--~~ ........ D D 4. Does the wetland unit have the opportunity to reduce flooding and erosion? (see p. 49) D Answer YES if the unit is in a location in the watershed where the flood storage, or reduction in water velocity, it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Answer NO if the water coming into the wetland is controlled by a structure such as flood gate, tide gate, flap valve, reservoir etc. OR you estimate that more than 90% of the water in the wetland is from groundwater in areas where damaging groundwater flooding does not occur. Note which of the following indicators of opportunity apply. Wetland is in a headwater of a river or stream that has flooding problems Wetland drains to a river or stream that has flooding problems Wetland has no outlet and impounds surface runoff water that might otherwise flow into a river or stream that has flooding problems -Other _______________ _ YES NO is 1 TOTAL -Hydrologic Functions Multiply the score from D 3 by D 4 Add score to table 011 p. 1 Wetland Rating Fonn -western Washington 6 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 multiplier I I I I I I I I I I I. I I I I I I I I I ,. I I I I I I I I I I I' I ,I I I I I Wetland name 01' number " .. ; .. R 1. Does the wetland unit have the potential to improve water quality? R R 1.1 Area depressions within the riverine that can trap sediments during a flo~ding event: . (PM p" Slur e. (AfOPS , DepreSSIOns covel' >3/4 area of wetland aft.. ~m45+ edJ2.' pomls = 8 Depressions covel' > 1/2 area of wetland cJ.LprtS:sr('rl" ~oints = ~ If depressions> Y, of area of unit draw polygons on aerial photo or map Depressions present but cover < 1/2 area of wetland . points = 2 No =0 R R 1,2 Characteristics of the vegetation in the unit (al'cas with >90% covel' at PCI'SOIl height): Tt'ees or shrubs> 213 the area of the unit' points = 8 Trees or shrubs> 1/3 area of the unit points = 6 ..3 Ungrazed, herbaceous plants> 2/3 area of unit Roints = 6 Ungrazed herbaceous plants> 1/3 area of unit (foints = "D Trees, shrubs, and herbaceous < 1/3 area of unit pomts -0 ~~~I~~~~~~~~~~~~~--------~-----Add the points in the boxes above R ~--+---------------------------------------------------------------------~-.~--R R R 2. Does the wetland unit have the opportunity to improve water quality? Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes Or groundwater downgradient from the wetland? Note which ofthefollowing conditions provide the sources o.l'poJ/utants, A unit may have pollutants coming/rom several sources, Inri any single source would qUi/Ii/yas opportunity, X. Grazing in the wetland or within I SOft X Untreated stonnwater discharges to wetland Tilled fields or orchards within ISO feet of wetland i. A stream or culvert discharges into wetland that drains developed areas, residential areas, fanned fields, roads, or clear-cut logging ~ Residential, urban areas, golf courses are within ISO ft of wetland ~ The river or stream linked to the wetland has a contributing basin where human activities have raised levels of sediment, toxic compounds or nutrients in the river waterabovestandat'dsforwaterquality ~ Cr&.t.. 0(1 3 D !?>{,,) ItS+-.ree cd Ct> I d~ oV" ~:.-----------------~~~. multiplier is 2 NO multiplier is 1 TOTAL -Wate.· Quality I·'unctions Multiply the score from R 1 by R 2 Add score to table on 1 Comments Wetland Rating Form -western Wa.shington 7 version 2 ypdated with new WDFW detinitiollS Oct. 2008 August 2004 (see p.53) multiplier Wetland name or number R R R R R R 3.1 storage Estimate the average width of the wetland unit perpendicular to the direction of the flow and the width of the stream or river channel (distance between banks). Calculate the ratio: ( average width of unit)/( average width o.fstream between b-:;a:;.n<k",s...-,:--.. If the ratio is more than 20 5fft I'Y\'" 12..4 oints = 9 If the ratio is between 10 -20 d; "'-s = 6 If the ratio is 5 -<10 Ic.h+le<.no/ ::.. ..... 3 00 f-l-points = 4 If the ratio is I -<5 points = 2 If the ratio is < I points = I or R 3.2 Characteristics that down water velocities during Treat large woody debris as "forest or shrub ". Choose the poinls appropriate for the best description. (polygons need to have >90% cover at person height NOT Cowardin classes): Forest or shrub for >1/3 area OR herbaceous plants> 213 area points = 7 Forest or shrub for> 1110 area OR herbaceous plants> 1/3 area (JlOints --3::> Vegetation does not meet above criteria pomts -0 Add the points in the boxes above R 4. Does the wetland unit have the opportunity to reduce flooding and erosion? Answer YES if the unit is in a location in the watershed where the flood"slorage. or reduction in water velocity. it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Note which of the following conditions apply. X There are human suuctures and activities downstream (roads. buildings. bridges, :f fanus) that can be damaged by flooding. There are natural resources downstream (e.g. salmon redds) that can be damaged by flooding Chlno.1t-Sf'o.w~ I'\R.M U' WC),SI1, Other ______ ~--------- (Answer NO if the major source o.(water to the wetland is controlled by a reservoir or the w~'i!llJ'd is tidalfrillge along the sides 0.( a dike) Comments multiplier is 2 NO mUltiplier is t TOTAL -Hydrologic Functions Multiply the score from R 3 by R 4 Add score to table on p. 1 Wetland Rating Form -western Washington 8 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 ,-------------------------------- I I I I I I I I I I I I I I I I I I .1 Wetland name or number L L L L 1. Does the wetland unit have the potential to impt'ove water quality? 1.1 Average the Vegetation is more than33fi (10m) wide Vegetation is more than 16 (5m) wide and <33ft Vegetation is more than 6ft (2m) wide and < 16 fi Vegetation is less than 6 ft wide cowart//'n c/asse:.): points = 6 points = 3 points = 1 points = 0 classes with widths marked Characteristics vegetation in the wetland: choose the appropriate description IhCII results in the highest points, and do not include any open water in your eslim(lte of coverage. The herb(lceous plants can be either the dominanl jorm or (IS an understory ill a shrub or/orest ,·omlnunity. These are not Cowurdin classes. Areu of Cover is tOUlI cover in the IInit, bUI it can be ill pCllches. NOTE: Herbaceous does not include aquatic bed. Cover of herbaceous plants is >90% of the vegetated area points = 6 Cover of herbaceous plants is >2/3 of the vegetated area points = 4 Cover of herbaceous plants is > I /3 of the vegetated area points = 3 Other vegetation that is not aquatic bed or herbaceous covers > 2/3 unit points = 3 Other vegetation that is not aquatic bed in > 113 vegetated area points = 1 Aquatic bed vegetation and open water cover> 2/3 of the unit points = 0 (see p.59) Figure_ I __________________________ ~~~~~~~~~~~~~~i~~~_~l-- I-----Add the points in the boxes above L ~~+---~----~----~----------------~----~--------------~~----------1~--------L L 2. Does the wetland have the opportunity to improve water quality? (see p.61) L Answer YES if you know or believe there are pollutants in the lake water, or polluted surface water flowing through the unit to the lake. Note which ofthejol/owing co/uti/'ion!sl provide the sOllrces of pol/II/an Is. A IIni/may have pol/u/(tnts comingfrom sei'erlll sources, bu/any single source would qualify (IS opportunity. Wetland is along the shores of a lake or reservoir that does not meet water quality standards -Grazing in the wetland or within 150ft Polluted water discharges to wetland along upland edge Tilled fields or orchards within 150 feet of wetland Residential or urban areas are within 150 ft of wetland Parks with grassy areas that are maintained, ballfields, golf courses (all within 150 ft. oflake shore) Power boats with gasoline or diesel engines use the lake -Other _______________ _ YES is 2 NO TOTAL -Water Quality Functions Comments is 1 Multiply the score from Ll by L2 AIM score to table 011 1 Wetland Rating F0I111 -westen! Washington 9 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 multiplier Wetland name or number L L 3. Does the wetland unit have the potential to reduce shorelinc ere.sirm? L 3 Distance along shore and average width of Cowardin classes along the lakeshore (do not include aquatic bed): (cIJoose tlJe highest scoring description that matches conditions ill the wetland) > r.; of distance is shrubs or forest at least 33 ft (10m) wide > r.; of distance is shrubs or forest at least 6 ft. (2 m) wide > \4 distance is shrubs or forest at least 33 ft (lOm) wide Vegetation is at least 6 ft (2m) wide (any type except aquatic bed) Vegetation is less than 6 ft (2m) wide (any type except aquatic bed) points = 6 points = 4 points = 4 points = 2 points = 0 ~ _________ ~_~~!!.£!l2J£'£!!:..!!!!!E~!\t!.:QQ:~~~!fl!:!~!2!!.~~~ __ ! ____ _ L Record the points from the box above ~--+-----------------------------------------------------------------4----L L 4. Does the wetland unit have the opportunity to reduce erosion? (.~ee p.63) Are there features along the shore that will be impacted if the shoreline erodes? Note which of the follOWing conditions apply. There are human structures and activities along the upland edge of the wetland (buildings, fields) that can be damaged by erosion. There are undisturbed natural resources along the upland edge of the wetland (e,g, mature forests other wetlands) than can be damaged by shoreline erosion -Other multiplier YES multiplier is 2 NO multiplier is ] L TOTAL -Hydrologic Functions Multiply the score from L 3 by L 4 Add score to table 011 p. 1 Comments Wetland Rating Fornl-western Washington 10 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 I I I I I , 'I I I I I I I I I I I I I I 'I I I I I I I I I I I I I . Wetland name or number s s s s S 1. Does the wetland unit have the potential to imp.·ove water quality? S 1.1 Characteristics of average slope . unit: Slope isl% or less (a l%slope has a 1/001 vertical drop in elevation/or every 100ft horizontal distance) points = 3 Slope is 1 % • 2% points = 2 Slope is 2% . 5% points = I Slope is greater than 5% points = 0 is clay or d~finitions) . YES=3 S 1.3 the trap Choose the points appropriate/or the description that best fits the vegetation illihe wetland. Dense vegetation means you he/ve trouble seeing the soil sUlface (> 75% covel), and uncut means not grazed or mowed and plants are higher than 6 inches. Dense, uncut, herbaceous vegetation> 90% of the wetland area points = 6 Dense, uncut, herbaceous vegetation> 112 of area points = 3 Dense, woody, vegetation> \oS of area points = 2 Dense, uncut, herbaceous vegetation> 1/4 of area points = I Does not meet any of the criteria above for vegetalion points = 0 (see p.64) ~--------------~~I~~~~~~~~~----~---- Add the points in the boxes above Total for S 1 s ~~~~~--~------~----~~--------~~--~.~---S S 2. Does the wetland unit have the opportunity to improve water quality? (see p.67) s Answer YES if you know or believe there are pollutants in groundwater or surface waler coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland. NOle which o/the following conditions provide the SOurces ofjJollutants. A unit may have pollutanls coming/rom several sources, bUI any single source would qualifY liS opportunity. Grazing in the wetland or within 150ft Untreated slonllwater discharges to wetland Tilled fields, logging, or orchards within 150 feet of wetland Residential, urban areas, or golf courses are within 150 ft upslope of wetland Other ______________ _ YES multiplier is 2 NO multiplier is 1 TOTAL -Wate.· Quality Functions Multiply the score ii'om S 1 by S2 Add score to table on 1 Comments Wetland Raling Form-weslern Washington 11 August 2004 version 2 Updated wilh new WDFW definitions Oct. 2008 multiplier Wetland name or number H 104. Interspersion of habitats (see p. 76) Decide from the diagrams below whether interspersion between Cowardin vegetation classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, medium, low, or none. " 0 ,,' None = 0 points Low = I point Moderate = 2 points ~ High = 3 points [riparian braided channels] NOTE: If you have four or more classes or three vegetation classes and open water the ratill is alwa s "hi h". Use map of Cowardiri vegetation classes H 1.5. Special Habitat Features: (see p. 77) Check Ihe habitatfiwtures that are present in the wetland. The number of checks is the number o.f points you put into the next column. LLarge, downed, woody debris within the wetland (>4in. diameter and 6 ft long). LStanding snags (diameter at the bottom> 4 inches) in the wetland L Undercut banks are present for at least 6.6 ft (2m) andlor overhanging vegetation extends at least 3.3 ft (1m) over a stream (or ditch) in, or contiguous with the unit, for at least 33 ft (10m) __ Stable steep banks of fine material that might be used by beaver or muskrat for denning (>30degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet turned grey/browl1) __ At least ~ acre of thin-stemmed persistent vegetation or woody branches are present in areas that are pennanently or seasonally inundated.(structuresfor egg-laying by amphibians) __ Invasive plants cover less than 25% of the wetland area in each stratum of plants NOTE: The 20% stated il1 early pril1tings of the manual 011 page 78 is al1 error. H 1. TOTAL Score -potential for providing habitat Add the scores (rom Hi.I, HJ.2, Hi.3, HI.4, Hi.S Comments Wetland Rating Form -western Washington 14 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 I I I I I I I I II I' I I I 3 I ---- 12-I ---_ ... Ii Ii 'I! , I .1 • I I I I I I I I I I I I '. I I I I I Wetland name or number H 1. Does the wetland unit have the potential to provide habitat for many species? H 1.1 Vegetation structure (see p. 72) H Check the types l.!lvegetaJion classes present (as defined by Cowardin)-Size thresholdfor each class is )i,; acre or more than 10% of the area il.mit is smaller than 2.5 {leres. __ Aquatic bed ~Emergent plants -78crub/sluub (areas where shrubs have >30% cover) ;:7 Forested (areas where trees have >30% cover) If the IInit has a/orested class check if __ The forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each covel' 20% within the forested polygon Add the IIl1mber olvegetatioll structllres that qualifY. If yo II have: Map of Cowardin vegetation classes p. 4 structures or more 3 structures 2 structures I structure points = 4 @ints-p points -I =0 Check the types of water regimes (hytlroperiod~~ present within the wetland. The water regime has to cover more than /0% of the wetland or )i,; acre /0 cOt/nt. (see texl for descriptions of hydroperio{/;) ~ts~' __ Permanently flooded or inundated 4 01' more types present ---2LSeasonally flooded or inundated 3 types present L Occasionally flooded or inundated 2 types present ~Saturated only I type present ~ Permanently flowing stream or river in, or adjacent to, the, wetland __ Seasonally flowing stream in, or adj acent to, the wetland poznts = 2 point = I points = 0 _._ Lake-Ji'inge wet/lmd = 2 points __ Freshwater lid{11 wetland = 2 points Map of hydro periods HI (seep. 75) Count the number of plant species in the wetland that cover at least 10 ft2. (di/Jerent palches of the same species Clm be combined to meelthe size Ihreshold) YOII do nOlhave 10 name the species. Do nol include Eurasian Milfoil. reed canlllygruss, pUiple looses/rile, If you counted: > 19 specie List species below if you wunl /0: species Chtr'j TrUll Y'e.oI 0,J.cJ..v.,. < 5 species .5(.>ZA.U1S wi liD,.) h-...... fJ/hC/(.I'JQ(('1 ;},atl+ n.ors~.:f!:L;/ Sl.j..~ ... wi /lDW tyWsS 25O++-I'USh c..rtt..pln~ b",.:H(.(W-P pCt51w'"t tl or S5 t S c5/(W(/h Sed9 e.. ~s SpwL.... Otil&,Y' as/) ~or(l PeIli.4'rv...<-+ ('Dolo!-(/l.o( o'Strd.o~,f)ood -:c-~ PllA.W1 .51H::.t< .5prnu ~.5 ..fir Pf'A..L.t.f.t, wi'llow jbcI.fu_ h-tntOatl-1C. Canadian Thislle points = 2 points = I points = 0 :3 Total for page _7-,-_ WeIland Raling F0I111-weslern Washington 13 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number H 1.4. Interspersion of habitats (.vee p. 76) Decide from the diagrams below whether interspersion between Cowardin vegetation classes (described in H I. I), or the classes and unvegetated areas (can include open watcr or mudflats) is high, medium, low, or none. o None = 0 points Low = 1 point Moderate = 2 points ~. High = 3 points [riparian braided channels] NOTE: If you have four or more classes or three vegetation classes and open water the ratin is alwa s "hi h". Use rna of Cowardiri vegetation classes H 1.5. Special Habitat Features: (see p. 77) Check the habitat features that are present in the wetland. The /lumber of checks is the /lumber o.fpoints you put into the next column. LLarge, downed, woody debris within the wetland (>4in. diameter and 6 ft long) . ...LStanding snags (diameter at the bottom> 4 inches) in the wetland L Undercut banks are present for at least 6.6 ft (2m) and/or overhanging vegetation extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the unit, for at least 33 ft (10m) __ Stable steep banks of fine material that might be used by beaver or muskrat for denning (>30degree slope) OR signs of recent beaver activity are present (cut shrubs or trees thai have not yet turned grey/browlI) __ At least y.; acre of thin-stemmed persistent vegetation or woody branches are present in areas that are pennanently or seasonally inundated. (structures for egg-laying by amphibians) __ Invasive plants cover less than 25% of the wetland area in each stratum of plants igure 3 NOTE: The 20% staled in early printings of the manual 011 page 78 is all erro,'. r-----------------------------~------------------~--------------------~--......... H 1. TOTAL Score -potential for providing habitat : 12- '--____________ .......:.A;,:d::;d;,.:l,;,:,h.:..e .::,:sc:.:0c...re=:s""fi.:.,;ro'-",;,:,I1..:,;H;..:Ic.... /,-",..:.H:.,;/",,' 2::':'..:.H,;;.;/:..;,.",3'c.:Hc.../:,,;'..;,,4,:...:I..:.i:.,;/ • ..:.5--60 ____ ... Comments Wetland Rating Form -western Washington 14 August 2004 version 2 Updated with new WOFW definitions Oct. 2008 I I I I , I I ./ ,I 'I I , I I I I , I I I I I I I I I I I I I I I Wetland name or number H 2. Does the wetland unit have the opportunity to provide habitat for many species? II 2.1 Buffers (see p. 80) Figure J. Choose the description Ihal best represents condilion of btdJer of wetland tlnil. 111e highest scoring criterionlhat applies to Ihe wetlewd is to be IIsed in the rating. See texlJiJr deJinition q{ "undislurbed. .. -100111 (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% of circumference. No structures are within the undisturbed palt of but IeI'. (relatively undisturbed also means no-grazing, 110 landscaping, no daily human usc) l'oints = 5 -100 m (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water> 50% circumference. Points = 4 -50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% circumference. Points = 4 -100 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water> 25% circumference, . Points = 3 -50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water for> 50% circumference. Points = 3 If buffel' does not meet any of the criteria above -No paved areas (except paved trails) or buildings within 25 m (SOft) of wetland > 95% circumference. Light to moderate grazing, or lawns are OK. Points = 2 X No paved areas or buildings within 50m of w'etland for >50% circumference. Light to moderate grazing, or lawns are OK. Points = 2 -Heavy grazing in buffer. Points = 1 -Vegetated buffers are <2m wide (6.6ft) for more than 95% of the circumference (e.g. lilled fields, paving, basalt bedrock extend to edge of wetland Points = O. '7 -Buffer does not meet any of the criteria above. Points = 1 c;r.. Aerial photo showinq buffers H 2.2 Corridors and Connections (see p. 81) H 2.2.1 Is the wetland pali of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at leas! 150 ft wide, has at least 30% covel' of slnubs, forest 01' native undisturbed prairie, that connects to estuaries, other wetlands or undisturbed uplands that are at least 250 acres in size? (dams in riparian corridors, heavily IIsed gmvel roads, paved roads. are considered breaks in the corrido'b .' YES = 4 points (go to H 2.3) <...9 go to H 2.2.2 H 2.2.2 Is the wetland P8lt of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 50ft wide, has at least 30% covel' of shlubs or forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a Lake-fringe wetland, ifit does not have an undisturbed corridor as in the question above? YES = 2 points (go 10 H 2.3) @= H 2.2.3 H 2.2.3 Is the wetland: within 5 ini (Skm) of a brackish or salt water estuary OR within 3 mi of a large field 01' pasture (>40 acres) OR)t I withi~i of a lake greater than 20 acres? (yESj= 1 point NO = 0 points Total for page 3 Wetland Rating Fonu -WeSlel'll Washinglon IS August 2004 version 2 Updated wilh new WOFW definitions OCI. 2008 Wetland name or number H 2.3 Near or adjacent to other priority habitats Iistcd by WDFW (see new alld co",plele de.~criptio"s of WDFW priority "abitars, afld rile coullties ill w"ic" tltey call befOlll/d, ill rite PHS report Itrlp:llwd(w.wa.govlhahlpltslist."'",) Which of the following priority habitats arc within 330ft (1 OOm) of the wetland unit? NOTE: the connections do not have to be relatively undisturbed. __ Aspen Stands: Pure or mixed stands of aspen greater than 0.4 ha (I acre). __ Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report p. 152). __ Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. __ Old-growthlMaturc forests: (Old-growth west of Cascade crest) Stands of at least 2 tree species, fOlming a multi-layered canopy with occasional small openings; with at least 20 trees/ha (8 trees/acre) > 81 em (32 in) dbh or> 200 years of age. (Mature forests) Stands with average diameters exceeding 53 cm (21 in) dbh; crown cover may be less that 100%; crown cover may be less that 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80 -200 years old west of the Cascade crest. __ Oregon white Oak: Woodlands Stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important (full descriptions in WDFW PHS J report p. 15lJ). _,,_Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. __ Westside Prairies: Herbaceous, non-forested plant communities that can either take the fonn of a dry prairie or a wet prairie (filii descriptions in WDFW PHS report p. 161). --x"Instrcam: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. __ Nearshore: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Pugct Sound Nearshore. (filII descriptions o/habitats and the d~finition o/relatively undisturbed are in WDFWreport: pp. 167-169 alld glossa/y in Appendix A). __ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological fonnations and is large enough to contain a human. _Cliffs: Greater than 7.6 m (25 ft) high and occurring below 5000 ft. _Talus: Homogenous areas of rock rubble ranging in average size 0.15 -2.0 m (0.5 -6.5 ft), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. __ Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of> 51 cm (20 in) in western Washington and are> 2 m (6.5 ft) in height. Priority logs are> 30 cm (12 in) in diameter at the largest end, and> 6 m (20 ft) long. . If wetland has 3 or more priority habitats = 4 points If wetland has 2 priority habitats =(3'iIOlii!J> If wetland has 1 priority habitat = 11rniiit No habitats = 0 points Note: All vegetated wetlands are by d~finitiol7 a priority !rabitat but are 1I0t included in this list. Nearby wetlands are addressed ill question H 2.4) Wetland Rating Fonn -westem Washington 16 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 I I I I I I I 'I I I I I I • I 3 I I I I I I I I I I I I I .' I I I I I Wetland name or number H 2.4 Wetland Landscape (choose the one description of the landscape around Ihe wetlalld Ihill . , best/its) (see p. 84) There are at least 3 other wetlands within Y, mile, and the connections between them are relatively undisturbed (light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads, fill, fields, or other development. points ~ 5 The wetland is Lake-fringe on a lake with little disturbance and there are 3 other lake-fringe wetlands within Y, mile points ~ 5 There are at least 3 other wetlands within \/, mile, BUT the connections between t~~~ disturbed . points ~ The wetland is Lake-fringe on a lake with disturbance and there are 3 other lake-thl1lli' wetland within Y, mile points = 3 There is at least 1 wetland within Y, mile. points = 2 There are no wetlands within Y, mile. points ~ 0 H 2. TOTAL Score -opportunity for providing habitat Add Ihe scores (rom H2.1.H2.2. H2.3. H2.4 TOTAL lor H 1 from page 14 Total Score for Habitat Functions -add the points tor HI, H 2 and record the result on p. 1 Wetland Rating FOlm -western Washington 17 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 3 -----I CJ I I I ----- /1.------ (j.\ Wetland name or number CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Please determine ~f the wetland meets the attributes described below and circle the appropriate answers altd Category. Wetland Type Category Check o.ff any criteria that apply to the wetland. Circle the CategO/y when the appropriate criteria are met. SC 1.0 Estuarine wetlands (see p. 86) Does the wetland unit meet the following criteria for Estuarine wetlands? -The dominant water regime is tidal, -Vegetated, and -With a salinity greater than 0.5 ppt. NOY YES = Go to SC 1.1 SC 1.1 Is the wetland unit within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, . Cat. I Environmental, or Scientific Reserve deSign~~~der WAC 332-30-151? YES = Category I NO 0 to SC 1.2 SC 1.2 Is the wetland unit at least I acre in size'iiii"d meets at least two of the following three conditions? YES = Category I NO = Category II Cat. I -The wetland is relatively undisturbed (has no diking, ditching, filling, Cat. II cultivation, grazing, and has less than 10% cover of non-native plant species. If the non-native Spartina spp. are the only species that cover more thanlO% of the wetland, then the wetland should be given a dual Dual rating (1111). The area of Spartina would be rated a Category" while the rating relatively undisturbed upper marsh with native species would be a 1111 Category J. Do not, however, exclude the area of Spartina in determining the size threshold of I acre. -At least l4 of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland has at least 2 of the following features: tidal channels, . depressions with open water, or contiguous freshwater wetlands. Wetland Rating Fonn -westen, Washington 18 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 I I I I I 1 I I I I I I I I I '" I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number SC 2.0 Natural Heritage Wetlands (see p. 87) Natural Helitage wetlands have been identified by the Washington Natural Heritage Program/DNR as either high quality undisturbed wetlands 01' wetlands that support state Threatened, Endangered, or Sensitive plant species. SC 2.1 Is the wetland unit being rated in a Section/Township/Range that contains a Natural Heritage wetland? (this question is used to screen out most sites before you need to contact WNHPIDNR) Sn'/R information from Appendix D _ or accessed from WNHI'/DNR web site 2/Z /'2.0/ 0 C.loSts"" I ~ ..,. z. 3 N R S t: .5-15 YES __ -contact WNHP/DNR (see p. 79) and go to SC 2.2 NO X SC 2.2 Has DNR identified the wetland as a high quality undisturbed wetland or as 01' as a site with state threatened or endangered plant species? YES = Category I , NO ~not a Heritage Wetland SC 3.0 Bogs (see p. 87) Does the wetland unit (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key be/ow to identifY if the wetland is Ct bog. l/yoll answer yes you will stilll/eed to "ate the wetlalld base(/ 011 itl·jimctiolls. 1. Does the unit have organic soil horizons (i.e. layers of organic soil), either peats 01' mucks, that compose 16 inches or more of the first 32 inches of the soil profile? (See Appendix B for a field key to identify organic soils)? Yes,- ~~Q.3 ~-~~Q2 2. Does the unit have organic soils, either peats 01' mucks that are less than 16 inches deep over bedrock, or an impelmeable hardpan such as clay 01' volcanic ash, or that are floating on a lake or pond? Yes -go to Q. 3 No -Is not a bog for purpose of rating 3. Does the unit have more than 70% cover of mosses at ground level, AND other plants, if present, consist of the "bog" species listed in Table 3 as a significant component of the vegetation (more than 30% of the total shrub and herbaceous cover consists of species in Table 3)? Yes -Is a bog for purpose of rating No -go to Q. 4 NOTE: If you are uncertain about the extent of mosses in the understory you may substitute that critelion by measuring the pH of the water that seeps into a hole dug at least 16" deep. If the pH is less than 5.0 and the "bog" plant species in Table 3 are present, the wetland is a bog. J. Is the unit forested (> 30% cover) with sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Englemann's spruce, or western white pine, WITH any of the species (or combination of species) on the bog species plant list in Table 3 as a significant component of the ground cover (> 30% coverage a/the total shrub/herbaceous cover)? 2. YES = Category I No ~ Is not a bog for purpose ofrating Wetland Rating Fonll -westcm Washington 19 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Cat. I Cat. I Wetland name or number SC 4.0 Forested Wetlands (see p. 90) Does the wetland unit have at least I acre of forest that meet one of these criteria for the Department ofFish and Wildlife's forests as priority habitats? If you answer yes you will still need to rate the wetland based on its/illletions. -Old-growth forests: (west of Cascade crest) Stands of at least two tree species, fonning a multi-layered canopy with occasional small openings; with at least 8 trees/acre (20 treeslhectare) that are at least 200 years of age OR have a . diameter at breast height (dbh) ()f32 inches (81 Col) or more. NOTE: The criterion for dbh is based on measurements for upland forests. Two-hundred year old trees in wetlands will often have a smaller dbh because their growth rates are often slower. The DFW criterion is and "OR" so old-growth forests do not necessarily have to have trees of this diameter. -Mature forests: (west of the Cascade Crest) Stands where the largest trees are 80 -200 years old OR have average diameters (dbh) exceeding 2 I inches (53cm); crown cover may be less that 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth. YES = Category I NO X not a forested wetland with special characteristics SC 5.0 Wetlands in Coastal Lagoons (see p. 91) Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? -The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks -The lagoon in which the wetland is located contains surface water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom) YES = Go to SC 5.1 NO..x not a wetland in a coastal lagoon SC 5. I Does the wetland meets all of the following three conditions? -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of invasive plant species (see list of invasive species on p. 74). -At least 1;1 of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland is larger than 1110 acre (4350 square feet) YES = Category I NO = Category II Wetland Rating Fonn -western Washington 20 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Cat. I Cat. I Cat. II I I I I I I ·1 I I I .1 I '1 '. I I I I I I I I I I I I I I I I I I I I I I I I Wetland name 01' number SC 6.0 Intcrdunal Wetlands (see p. 93) Is the wetland unit west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? YES -go to SC 6.1 NO X not an interdunal wetland for rating If yo II aflswer yes yo" will still fleed 10 /'{Ite the wet/ami based Ofl its jimctiofls. In practical telms that means the following geographic areas: • Long Beach Peninsula-lands west of SR 103 • Grayland-Westport~ lands west ofSR 105 • Ocean Shores-Copalis-lands west of SR 115 and SR 109 SC6.1 Is the wetland one acre or larger, 01' is it in a mosaic of wetlands that is once acre 01' larger? ' YES = Category II NO -go to SC 6.2 SC 6.2 [s the unit between 0.1 and 1 acre, or is it in a mosaic of wetlands that is between 0.1 and I acre? YES = Category III (!;i~~t~~!i~YX!i,fi~¥~!'~n~,~~i,Q~:~,#,;§~~~i,#.,I"q~~f~~t,~i!~!i#~;!:;;!,\\t:r;";)k;;;:;\ii},.xd(,,t;i,iS';, ,', ""'Chdo'$e:the/jhighes('t',;ilfjngif.:wetlandfall$,,intd.~·eveiy:ilcaiiigij~ies;jiiid:W/ciji;d'dn'!/ f;~ii~~~{iAl~W~~~;!~:!~~ij;~ll~{~~\~;~;l~~~;~'~Wgf'~bJi;1~~~i~~'gi~)~jl':{S';$,\":~f:;:;;::f;:::':"~,\ Wetland Rating Forlll-western Washington 21 version 2 ,Updated with new WDFW definitions Oct. 2008 August 2004 Cat. II Cat. III rJlA I LI • . * . c • I ~ :::r Q) I ~ a. s: Q) ;; I ~ '< () """'" CD I o r-g co c IQ '" ~ ::J Co I g. ~ CD 7' < Q) ~ ~ -- I ::J a. '" :j" 1ii I :a 0 .;;? CD , "8 '< ~ CD I i 1"'+ '" I V-) Q) ::J a. ~ IO~ 0 ~~ 0 I~ ~ (0 "" ;s ~.f' ~ I~ . » CD I """'" _. Q) -I 0 J.\ I • Ii': c.s:. ~ ,.. I ~ .., N." OJ! I --- • . * . • '" --.... ~ -,~ --~ "" .... - - -IViay CreeK valley vvetlana LOu9 Aerial ~JCA("l 2- Legend - ----.: U S Fish and Wildlife Service: Conus national wellands inventory -polygons 61~(1L Ow-Line SS : SCrlotb -Sh'l.l. ... r-----------'F.~ o 4eo 96() 1.920 I I I I I I I I I I I I I I I I I I I " , ~ .L. , Appendix B -Wetland Delineation Data Forms May Creek Channel Restoration Wetland Delineation 27 March 2010 I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: May Creek VaUey -DNRP King County DNRP lnvestigator(s): Miller, Martin, Clark Landform (hillslope, terrace, etc.): Valley Subregion (lRR): lat: Soil Map Unit Name: RdC, Bh 47.51495 CitylCounty: King Sampling Date: State: WA Sampling Point: Soil Pit #1 Section, Township, Range: 52, T23N, R5E Local relief (concave, convex, none): flat Slope (%): 0.5 Long: -122.14239 Datum: No NWI classification: o (If no, explain in Remarks.) PEM/PSS Are climatic I hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D, Soil D, Or Hydrology D. significanlly disturbed? Are Vegetation D, Soil D, Or Hydrology D, naturally problematic? Are ~Normal Circumstances" present? Yes 181 No 0 (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS Attach site map showing sampling point locations transects Important features etc -, Hydrophytic Vegetation Present? Yes 181 No 0 Hydric Soil Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Yes 181 . No 0 Wetland Hydrology Present? Yes 181 No 0 Remarks: SP #1 south of creek just west of barbed wire fence (probably 1.1 property east of 1481h ) -about 30·35 feet south of creek. VEGETATION Use scientific names of Dlants Tree Stratum (Plot Size: 10m) 1. Prunus spp. 2. 3. 4. Sapling/Shrub Stratum (Plot Size: 10m) 5. Oem/eria cerasiformis 6. Salix sitchensis 7. Salix scou/eriana 8. 9. Herb Stratum (Plot Size: Sm) 10. Pha/arls arundinacea 11. Unknown grass 12. Unknown grass 13. 14. 15. 16. 17. 18. 19. 20. Woody Vine Stratum (Plot Size: ) 1. Rubus procerus 2. % Bare Ground in Herb Stratum 65 Absolute "10 Cover 30 30 5 30 30 65 30 5 Trace 35 Trace 130 Dominant Species? Y = Total Cov~r Indicator Slatus FACU N FACU Y Y = Total Cover Y N N = Total Cover N = Total.Cover FACW FAC FACW ? ? FACU Dominance Test Worksheet: Number of Dominant Species That Are OBl, FACW, or FAG: Total Number of Dominant SpeCies Across All Strata: Percent of Dominant Species That Are OBl, FAGW, or FAG: Prevalence Index worksheet: Total "10 Cover of: OBl species FAGW species FAC species FAGU species UPl species 3 4 75 Multiply by' x1 = ><2= x3 = x4 = x5 = (A) (8) (NS) Column Totals: (A) (8) Prevalence Index = BfA = Hydrophytic Vegetation Indicators: X Dominance Test is >50"10 Prevalence Index is !3.0' Morphological Adaptations' (Provide supporting data in Remarks or on a separate sheet) Wetland NonNascular Plants' Problematic Hydrophytic Vegetation' (Explain). 'Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytlc Vegetation Present? Ye. No o Remarks: Starting to see buds. This is a forested/scrub-shrub portion of the wetland along the stream. US Army Corps of Engineers Westem Mountains, Valley, and Coast -Interim Version I Project Site; May Creek Valley -ONRP SOIL s p I amollna oint: #1 Profile Description: (Describe to the depth needed to document the Indicator or conflnn the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type' Loc2 Texture Remarks ---------a_18ft 10YR 211 100 Too small color 1 C M clay I I I 'Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coaled Sand Grains. 2Location: PL=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric 50118 3 : 0 Histosol (A1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Greyed Matrix (F2) 0 Depleted Below Dark Surface (A11) 181 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (S1) 0 Depleted Dark Surface (F7) 3 ,ndicators of hydrophytic vegetation and weUand 0 Sandy Gleyed Matrix (S4) 0 Redox Depressions (F8) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): . Type: Depth (Inches): Hydric Soils Present? Ye. 181 No 0 I Remarks: Very uniform matrix, all one horizon within 18 inches. Contains live roots. I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 181 Surface Water (A 1) 0 Water-Stained Leaves (B9) 0 Water-Stained Leaves (B9) 181 High Water Table (A2) (except MlRA 1,2, 4A, and 4B) (MLRA " 2, 4A. and 48) I 181 Saturation (A3) 0 Salt Crust (811) 0 Drainage Pattems (910) 181 Water Marks (81) 0 Aquatic Invertebrates (813) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (82) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (85) 0 Recent Iron Reduction in Tilled Soils (G6) 0 FAG-Neutral Test (05) I 0 Surface Soil Gracks (86) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (88) Field Observations: I Surface Water Present? Yes 0 No 181 Depth (inches): Water Table Present? Yes 181 No 0 Depth (inches): Binches Saturation Present? Yes 181 No 0 Depth (inches): o inches Wetland Hydrology Present? Ve. 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: About 35 feet from stream in an area with less reed canarygrass. Some standing water present within about 10 feet. Assuming hydrology would also be present later in the grOWing season. I US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanUOwner: Investigator(s): May Creek Valley -DNRP King County DNRP Miller, Martin, Clark Landform (hilJ!ilope, terrace, etc.): Valley Subregion (LRR): Lat: Soil Map Unit Name: RdC, Bh 47.51495 City/County: King State: WA Sampling Date: Sampling Point Section, Township, Range: . $2, T23N. R5E 1-21-2010 Soil Pit #2 Local relief (concave, convex, none): flat Slope (%): 0.5 Long: No -122.14239 Datum: NWI classification: o (If no, explain in Remarks.) PEM/PSS Are climatic I hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D, Soil D. Or Hydrology D, significantly disturbed? Are "Normal Circumstances" present? Yes t8I No 0 Are Vegetation D, Soil D. Or Hydrology D, naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS Attach site map showing sampling point locations transects Important features etc -, , , Hydrophytic Vegetation Present? Yes 0 No 181 Hydric Soil Present? Yes 0 No 181 Is the Sampling Area within a Wetland? Yes 0 No 181 Weiland Hydrology Present? Yes 0 No 181 Remarks: Too many grasses were present that we could not identify given the time of year for us to feel confident about the vegetation analysis; however, we are comfortable In saying this sample area is not within a wetland because the hydric soil and hydrology are not present. VEGETATION Use scientific names of Dlant5 Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. None Number of Dominant Species That Are 1 (A) 2. OBl, FACW, or FAC: 3. Total Number of Dominant Species Across (B) All Strata: 2 4. • = Total Cover Percent of Dominant Species That Are OBl, FACW, or FAC: 50 (NB) Sapling/Shrub Strat"m (Plot Size: 10m) 5. Cytlsus scoparius (scotch broom) Trace N ? Prevalence Index worksheet: 6. Total,,& Qover of: M,ulliQI:tb:t: 7. OBl species 0 x1 = 0 8. FACW species 15 x2 = 3. 9. FAC species .2 .x3 = 126 0 = Total Cover FACU species .2 x4 = 168 Herb Stratum (Plot Size: 5m) UPL species 0 x5= • 10. Thistle species Trace N ? Column Totals: 99 (A) 32' (B) 11. Festuca .rundlnacea 42 Y FAC Prevalence Index = BfA = 3.2 12. Datctylls g/omerafa 42 Y FACU Hydrophytic Vegetation Indicators: 13. Pha/aris arundinacea 15 N FACW No Dominance Test is >50% 14. Unknown grasses No Prevalence Index is !3.01 15. Morphological Adaptations 1 (Provide supporting data in 16. Remarks or on a separate sheet) 17. Wetland Non-Vascular Plants 1 18. Problematic Hydrophytic Vegetation 1 (Explain) 19. 20. llndicalors of hydric soil and wetland hydrology must be present, 99 = Total Cover unless disturbed or problematic. Woody Vine Strat"m (Plot Size: 10m) 1. Rubus procerus Trace N FACU 2. 99 = Total Cover Hydrophytic Vegetation % Bare Ground in Herb Stratum 0% Present? Ve. 0 No 181 Remarks: us Army Corps of Engineers Western Mountains, Va/ley, and Coast -Interim Version I Project Site: May Creek Valley -DNRP SOIL s p #2 I ampllnQ Oint: Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type l loc2 Texture Remarks ---------0-8" 7.SYR 2.S13 100 2.SYR SI8 1 C M Sandy loam 8·1S-10YR 0/4 100 Loamy sand Contains large gravels I I I 1Type : C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Localion: PL=Pore Lining, M=Matrix Hydric Soli Indicators: (Applicable to all LRRs. unless otherwise noted.) Indicators for Problematic Hydric 501la l : 0 Histosol (A 1) 0 Sandy Redox (85) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (S6) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Glayed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 0 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (S1) 0 Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (F8) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Salls Present? Ve. 0 No 181 I Remarks: This soil is dry as a bone and very bright. About 10 feet north of this soil pit (towards the wetland). another hole has a grayish transition (Gley1 5110Y) at 10-11 inches at approximate boundary between reed canarygrass and blackberry. About 5 feet north of this soil pit the color is 2.5Y 5/2 in bottom of the pit. I HVDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A 1) 0 Water-Stained Leaves (B9) 0 Water-Stained Leaves (B9) 0 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1. 2. 4A, and 4B) I 0 Saturation (A3) 0 Salt Crust (B11) 0 Drainage Patterns (B10) 0 Water Marks (B 1) 0 Aquatic Invertebrates (813) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (82) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (C9) I 0 Orin Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorpnic Position (02) 0 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (85) 0 Recent Iron Reduction in TIlled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (86) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (88) I Field Observations: Surface Water Present? Yes 0 No 181 Depth (inches): Water Table Present? Yes 0 No 181 Depth (inches): Saturation Present? Yes 0 No 181 Depth (inches): Wetland Hydrology Present? Ya. 0 No 181 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: No groundwater within 18 inches of surface. I us Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I ,-------------------------------------------- I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanVOwner: I nvestigalOr( s): May Creek Valley -DN RP . King County DNRP Martin, Clark City/County: King Sampling Date: State: WA Sampling Point: Section, Township, Range: 52, T23N, R5E 1-26-2010 Soil Pit #3 Landform (hillslope, terrace, etc.): Valley Lal: Local relief (concave, convex, none): flat Slope (%): 0.5 Subregion (LRR): 47.51495 Soil Map Unit Name: RdC. Bh Are climatic I hydrologic conditions on the site typical for this time of year? Yes long: -122.14239 Datum: No NWt classification: o (If no, explain in Remarks.) PEM/PSS Are Vegetation 181, Soil D, Or Hydrology D, significantly disturbed? Are "Normal Circumstances" present? Ves tgI No 0 Are Vegetation D, Soil D, Or Hydrology D, naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, Important features, etc. Hydrophylic Vegetation Present? Yes 181 No 0 Hydric Soil Present? Wetland Hydrology Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Yes 181 No 0 Yes 181 No 0 Remarks: Soil Pit #3 Is located on Colasurdo property, just east of the tributary along the access road. Chose this location because there are horses south of the fence. The vegetation In this area is mowed and grazed. VEGETATION -Use scientific names of Dlants Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. None Number of Dominant Species That Are ? (A) 2. 08L. FACW. or FAC: 3. Total Number of Dominant Species Across 2 (8) 4. All Strata: 0 = Total Cover Percent of Dominant Species That Are ? (AlB) §~(;!liD9/§hrub §lrntum (Plot Size: 10m) OSl, FACW, or FAC: 5. None Prevalence Index worksheet: 6. TQtS!1 O{~ QQver of: Multil2l~ Ill' 7. OBl species x1 = 8. FACW speCies ? x2= ? 9. FAC species x3 = 0 = Total Cover FACU species x4 = Herb Strat!.!m (Plot Size: 5m) UPL species x5= 10. Juncus effusus 51 Y FACW Column Totals: (A) (B) 11. Unknown pasture grasses 42 Y ? Prevalence Index = BIA ? 12. Ranunculus repens Trace N FACW Hydrophytic Vegetation Indicators: 13. Moss species 5 N ? ? Dominance Test is >50% 14. ? Prevalence Index is '::'3.0 ' 15. Morphological Adaptations 1 (Provide supporting data in 16. Remarks or on a separate sheet) 17. Wetland Non-Vascular Plants' 18. Yo. Problematic Hydrophytic Vegetation' (Explain) 19. 20. 'Indicators of hydric soil and wetland hydrology must be present, 9. = Total Cover unless disturbed or problematic. ~Qod~ :iiD~ SlrS!tum (Plot Size: ) 1. Rubus procerus Trace N FACU 2. 98 = Total Cover Hydrophytlc Vegetation % Bare Ground in Herb Stratum Present? Yes \81 No o Remarks: Vegetation may be marginal, but It is difficult to determine because the area is highly disturbed with previous horse use, Some of the dominant grass types cannot be determined due to the season and mowing, Based on the large amount of Juncus effusus, and the obvious Indicators of hydrology and hydric soli we are assuming that the vegetation would be hydric If given an opportunity to naturally grow, US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Valley -DNRP SOIL Sampling Point: #3 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of indicators.) I I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type' Loc2 Texture Remarks ---------0-6.5-5YR 2.5/1 100 Loamy sand Saturated to the surface 6.S-11S 10YR 5/4 90 10YR 4/6 10 C M Silty loam I 11.5-16-10YR 4/6 100 Sitty loam I I 'Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Localion: PL=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils': 0 Histosol (A1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Malerial (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (51) 0 Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (Fa) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Solis Present? Ve. 181 No 0 I Remarks: At line between NB horizons, contained charcoal-like organic malerial. < 1 cm band of mottles between NB horizons. I HVDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A1) 0 Water-Stained Leaves (B9) 0 Water-Stained Leaves (B9) 181 High Water Table (A2) (except MlRA 1, 2, 4A, and 48) (MlRA 1, 2, 4A, and 48) I 181 Saturation (A3) 0 Salt Crust (B 11) 0 Drainage Patterns (B10) 0 Water Marks (B1) 0 Aquatic Invertebrates (613) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (B2) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (B3) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mal or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (BS) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (86) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR Al 0 Inundation Visible on Aerial Imagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hun:tmocks (07) 0 Sparsely Vegetated Concave Surface (BB) I Field Observations: Surface Water Present? Yes 0 No 181 Depth (inches): Water Table Present? Yes 181 No 0 Depth (inches): 5.5- Saturation Present? Yes 181 No 0 Depth (inches): surface Wetland Hydrology Present? Ve. 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: I US Anny Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I ~----------------------------------------------- I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: Investigator(s): May Creek Valley -DNR~ King County DNRP Martin, Clark Landform (hillslope, terrace, etc.): Valley Subregion (lRR): lat: Soil Map Unit Name: RdC, Bh 47.51495 City/County: King Sampling Dale: 1-26-2010 State: WA Sampling Point: Soil Pit #4 Section, Township, Range: S2, T23N, R5E Local relief (concave, convex, none): flat Slope (%): 0.5 Long: -122.14239 Datum: No NWI classification: o (If no, explain in Remarks.) PEMIPSS Are climatic f hydrologic conditions on .the site typical for this time of year? Yes Are Vegetation D, Soil D, Or Hydrology D, significantly disturbed? Are Vegetation D, Soil D, Or Hydrology D, naturally problematic? Are "Normal Circumstances~ present? Yes 181 No 0 (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects Important features, etc. , Hydrophytic Vegetation Pre'sent? Ves 181 No 0 Hydric Soil Present? Ves 181 No 0 Is the Sampling Area within a Wetland? Ve. 181 No 0 Wetland Hydrology Present? Ves 181 No 0 Remarks: Soil Pit #4 is located just southeast of SE May Valley Rd/148th Avenue SE intersection. Pit dug at the northern extent of the Spirea near 148th. VEGETATION -Use scientific names of plants . Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. Fraxinus latifalia 60 Y FACW Number of Dominant Species That Are 3 (A) 2. Fruit tree 5 N ? OSl, FACW, or FAC: 3. Total Number of Dominant Species Across 3 (B) 4. All Strata: 65 = Total Cover Percent of Dominant Species That Are 100% (AlB) Sapling/Shrub Stratum (Plot Size: 10 m) OBL, FACW, or FAC: 5. Spirea douglasll 15 N FACW Prevalence Index worksheet: 6. Rosa pisocarpa 20 V FAC I2ll!1 0&1 QQver of: M!.!llipl~ tl~· 7. eBl species x1 = B. FACW species ><2= 9. FAC species x3 = 35 = Total Cover FACU species x4 = Herb Stratum (Plot Size: Sm ) UPl species x5 = 10. Phs/arls srundinacea 100 V FACW Column Totals: (A) (B) 11. Prevalence Index = B/A = 12. Hydrophytlc Vegetation Indicators: 13. Ve. Dominance Test. is >50% 14. Prevalence Index is !3.0' 15. Morphological Adaptations' (Provide supporting data in 16. Remarks or on a separate sheet) 17. Weiland Non-Vascular Plants' 1B. Problematic Hydrophytic Vegetation' (Explain) 19. 20. 'Indicalors of hydriC soil and wetland hydrology must be present, 100 = Total Cover unless disturbed or problematic. WQQg:t ~i[]ft S:tralum (Plot Size: ) 1. 2. 200 = Total Cover Hydrophytlc Vegetation % Bare Ground in Herb Stratum 0 Present? Ves 181 No 0 RemarKs: us Army Corps C?f Engineers Western Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Valley -DNRP SOIL Sampling Point: #4 Profile Description: (Describe to the depth needed to document the Indicator or conflnn the absence of Indicators.) I I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Typal Lao' Texture Remarks --------- 0-B.5" 10YR 2/1 100 Clay Oxidized roots B.5-13.5" 2.5Y 2.511 50 10YR 5/6 50 Clay Bottom 1/3 of layer has mottles I 13.5-18 10YR 2/1 Clay Organic pieces, oxidized roots I I IType: C= Concentration, D=DepJetion, RM=Reduced Matrix. CS=Covered or Coated Sand Grains. 2location: PL=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric 501ls3 : 0 Histosol (A 1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A11) 181 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (Sl) 0 Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (S4) 0 Redox Depressions (Fa) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Soils Present? Ve. 0 No 0 Remarks: The soil in the third layer is actually darker than the color noted, but there was not a good match in the Munsell. I I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A 1) 181 Water~Stained leaves (89) 0 Water~Stained leaves (B9) 181 High Water Table (A2) (except MLRA 1,2, 4A, and 48) (MLRA 1, 2, 4A, and 48) I 181 Saturation (A3) 0 Salt Crust (B11) 0 Drainage Pattems (810) 181 Water Marks (81) 0 Aquatic Invertebrates (813) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (82) 181 Hydrogen Sulfide Odor (Cl) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (B3) 181 Oxidized Rhizospheres along living Roots (C3) 0 Geomorphic Position (02) 181 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (BS) 0 Recent Iron Reduction in Tilled Soils (CG) 0 FAC·Neutral Test (OS) I 0 Surface Soil Cracks (86) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR Al 0 Inundation Visible on Aerial Imagery (B7) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (B8) Field Observations: I Surface Water Present? Yes 0 No 181 Oepth (inches): Water Table Present? Yes 181 No 0 Depth (inches): 4.5" Saturation Present? Yes 181 No 0 Depth (inches): surface Wetland Hydrology Present? Ve. 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: I US Army Corps of Engineers Western Mountains, Val/ay, and Coast -Interim Version I ,----------------------------------------------------------------------------------------------- I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanVOwner: Investigator(s): May Creek. Valley -DNRP King County ONRP Miller, Clark Landform (hillslope, terrace, etc.): Valley Subregion (LRR): Lat Soil Map Unit Name: RdC, Bh 47.51495 City/County: King Sampling Date: State: WA Sampling Point: Soil Pi! #5 Section, Township, Range: 82, T23N, R5E Local relief (concave, convex, none): flat Slope (%): 0.5 Long: -122.14239 Datum: No NWI classification: o (If no, explain in Remarks.) PEMfPSS Are climatic I hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D. Soil D. Or Hydrology D, significanlly disturbed? Are "Normal Circumstances" present? Yes ~ No 0 Are Vegetation 0, Soil D, Or Hydrology D, naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations transects Important features etc , , Hydrophytic Vegetation Present? Ves 0 No 181 Hydric Soil Present? Yes 0 No 181 Is the Sampling Area within a Wetland? Yo. 0 No 181 Wetland Hydrology Present? Yes 0 No 181 Remarks: Soil Pit #515 located slightly east and just upslope of Soli Pit #4 (SE of May Valley Rd/148t~ Ave SE intersection). Selected spot within the change from reed canarygrass to blackberry. VEGETATION -Use scientific names of plants Tree Stratum (Plot Size: 10m) 1. Acersp.* 2. Prunus sp.· 3. 4. SaphngfShrub Stratum (Plot Size: 10m) 5. Oemlaria cerasiformis 6. Cory/us cornuta* 7. B. 9. Herb Stratum (Plot Size: 5m) 10. Po/ystichum munJtum 11. PteridJum aqulllnum 12. Phs/aris arundinacea 13. 14. 15. 16. 17. 1B. 19. 20. Woody Vine Stratum (Plot Size: ) 1. Rubus procerus 2. % Bare Ground in Herb Stratum Absolute % Cover 25 15 40 20 33 53 20 20 20 60 45 19B Dominant Species? Y Y = Total Cover Indicator Status FACU FACU Y FACU Y FACU = Total Cover Y Y y. = Total Cover Y = Total Cover FACU FACU FACW FACU Dominance Test Worksheet: Number of Dominant Species That Are OBl, FACW, or FAC: Total Number of Dominant Species Across All Strata: Percent of Dominant Species That Are OSl, FACW. or FAC: Prevalence Index worksheet: Tota! % Cover of: Del species 0 FACW species 20 FAC species 0 FACU species 178 (A) 9 (B) 10 (AlB) Multiply by: xl = 0 x2 = 40 x3= 0 x4 = 712 x5 = UPl species Column Totals: o 198 (A) o 752 (B) Prevalence Index = BfA = 3.8 Hydrophytlc Vegetation Indicators: No No No No No Dominance Test is >50% Prevalence Index is !S3.0' Morphological Adaptations' (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants' Problematic Hydrophytic Vegetation' (Explain) 'Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytic Vegetation Present? Yes o No Remarks: ·Vegetation was hard to Identify. The cherry tree appears to be ornamental-it is next to an ornamental cedar and the maple appears to be a sugar maple and not a n~t1ye maple, but It is hard to tell this time of year. us Army Corps of Engineers Western Mountains, Valley. and Coast -Interim Version I Project Site: May Creek Valley -DNRP SOIL p' #5 I Samollna Oint: Profile Description: (Describe to the depth needed to document the Indicator or conflrm the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type' Loc2 Texture Remarks --------- 0-18" 7.5YR 3/3 100 5VR 518 5 Clay Small mottles throughout I I I 'Type: C= Concentration, D=Depietion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2location: Pl=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Solls3: 0 Histosol (A 1) 0 Sandy RedOX (55) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (All) 0 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (FS) 0 Sandy Mucky Mineral (51) . 0 Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (Fa) hydrology must be present, unless disturbed or oroblematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Salls Present? Vo. 0 No 181 I Remarks: I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A 1) 0 Water-Stained leaves (B9) 0 Water-Stained leaves (89) 0 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1, 2. 4A, and 48) I 0 Saturation (A3) 0 Sail Crust (811) 0 Drainage Patterns (810) 0 Water Marks (81) 0 Aquatic Invertebrates (813) 0 Dry-Season Waler Table (C2) 0 Sediment DepOSits (82) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (Cg) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (B4) 0 Presence of Reduced Iron (C4) 0 Shallow Aquilard (03) 0 iron Deposits (B5) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (88) I Field Observations: Surface Water Present? Ves 0 No 181 Depth (inches): Water Table Present? Ves 0 No 181 Depth (inches): Saturation Present? Ves 0 No 181 Depth (inches): Wetland Hydrology Present? Vo. 0 No 181 (includes capillary fringe) I Describe Recorded Data (stream gauge. monitoring well, aerial photos, previous inspections), if available: I Remarks: No indicators of hydrology are present here. I us Army Corps C?' Engineers Westem Mountains, Valley, and Coast -Inten'm Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: May Creek Valley -DNRP King County DNRP Investigator(s): Miller, Clark Landform (hillslope, terrace, etc.); Subregion (LRR): Soil Map Unit Name: RdC, Bh Valley Lat: 47.51495 City/County: King Sampling Date: State: WA Sampling Point: Section, Township, Range: 52. T23N, R5E 2-24-2010 Soil Pit #6 Local relief (concave, convex, none): flat Slope (%): 0.5 Long: No -122.14239 Datum: NWI classification: o (If no, explain in Remarks.) PEMfPSS Are climatic I hydrologic conditions on the site typical for this lime of year? Yes Are Vegetation 0, Soil D.' Or Hydrology D. significantly disturbed? Are Vegetation D, Soil D, Or Hydrology D. naturally problematic? Are ~Normal Circumstances· present? Yes 181 No 0 (If needed, exptain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects Important features etc , Hydrophytic Vegetation Present? Yes 181 No 0 Hydric Soil Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Yes 181 No 0 Wetland Hydrology Present? Yes 181 No 0 • Remarks: VEGETATION -Use scientific names of Dlants Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. ThuJa pl/cata 20 Y FAC Number of Dominant Species That Are 3 (A) 2. Pseudotsuga menz/es/J 30 Y FACU' OBl, FACW, or FAC: 3. Alnus ,ubra 35 Y FAC Total Number of Dominant Species Across 4. Fraxlnus latlfolia 5 N FACW All Strata: 5 (B) 5. Prunus spp. 5 N FACU 95 = Total Cover Percent of Dominant Species That Are 60 (NB) Sapling/Shrub Stratum (Pial Size: 10m) OBl, FACW, or FAC: 5. Oem/eria ceras/formis 5 N FACU Prevalence Index worksheet:. 6. Rubus spectabills 30 Y FAC Total % Cover st Multiply: by:: 7. Symphor/carpos albus 5 N FACU OBl species x1 = 8. Ame/anchie, a/n/folla 20 Y FACU FACW species x2 = 9. FAC species x3 = 50 = Total Cover FACU species x4 = Herb Stratum (Plot Size: 5m) UPl species x5= 10. Po/ystlchum munitum 2 N FACU Column Totals: (A) (B) 11. moss species·· 60 Y ? Prevalence Index = B/A = 3.4 12. Hydr~phytic Vegetation Indicators: 13. Yes Dominance Test is >50% 14. Prevalence Index is ::='3.0' 15. Morphological Adaptations' (Provide supporting data in 16. Remarks or on a separate sheet) 17. Wetland Non-Vascular Plants' lB. Problematic Hydrophytic Vegetation' (Explain) 19. 20. , Indicators of hydric soil and wetland hydrology must be present, 2 = Total Cover unless disturbed or problematic. Woody: Vin!;! SlratmD (Plot Size: ) 1. Rubus proce'us 10 N FACU 2. 167 = Total Cover Hydrophytic Vegetation % Bare Ground in Herb Stratum Present? Yes 181 No 0 Remarks: *The indicator status of douglas fir is stili being studied. One of the fir trees in this plot was growing In standing water. ··We did not include the moss in the dominance calculations. We also saw a trace of the native blackberry but did not Include that because the amount was <1%. This area passes based On the dominance test, so based on this finding hydrophytic vegetation is determined to be present. US Army Corps of engineers Westem Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Valley -DNRP SOIL Sampling Point: #6 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type' Loc2 Texture Remarks --------- 0-5" 10VR 2/1 100 Clay Almost to black to match the Munsell 5-18-10YR 2/1 100 Too small, faint 20 C M Clay Texture is even more sticky than top layer I I I 'Type: C= Concentration, O=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore lining, M=Matrix HydriC Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric 501ls 3: 0 Histosol (A 1) 0 Sandy Redox (85) 0 2 em Muck (A10) I 0 Histie Epipedon (A2) 0 Stripped Matrix (86) 0 Red Parent Material (TF2) 0 Black Histic (A3) 0 loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 18! Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (FG) 0 Sandy Mucky Mineral (S1) 0 Depleted 'Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (S4) 0 Redox Depressions (F8) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Salls Present? Ve. 18! No 0 I Remarks: Both layers are clay, but the top layer is more crumbly and contains small gravels. I HVDROLOGV I WetJand Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A1) 0 Water-Stained Leaves (B9) 0 Water-Stained leaves (B9) 18! . High Water Table (A2) (except MLRA 1. 2, 4A, and 48) (MLRA 1, 2, 4A, and 48) I 18! Saturation (A3) 0 Salt Crust (811) 0 Drainage Patterns (810) 0 Water Marks (B1) 0 Aquatic Invertebrates (B13) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (B2) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03). 0 Iron Deposits (B5) 0 Recent Iron Reduction in Tilled Soils (CG) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (B7) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (B8) I Field Observations: Surtace Water Present? Yes 0 No 18! Depth (inches): Water Table Present? Yes 18! No 0 Depth (inches): 9" Saturation Present? Vas 18! No 0 Depth (inches): surface Wetland Hydrology Present? Ve. 18! No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), jf available: I Remarks: I US Army Corps of Engineers Westem Mountains, Valley, and Coast -Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanUOwner: Investigator(s): May Creek Valley. DNRP King County DNRP Miller, Martin, Clark landform (hillslope, terrace, etc.); Valley Subregion (lRR): Lat: Soil Map Unit Name: RdC, Bh 47.51495 City/County: King Sampling Date: State: WA Sampling Point: Section, Township, Range: 52, T23N, RSE 2-24-2010 Soil Pit #7 local relief (concave, convex, none): flat Slope ("!o): 0.5 long: ·122.14239 Datum: NWI classification: PEM/PSS 181 No 0 (If no, explain in Remarks.) Are climatic I hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D, Soil D, Or Hydrology D, significantly disturbed? Are Vegetation D, Soil D, Or Hydrology D, naturally problematic? Are "Normal Circumstances· present? Yes 181 No 0 (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, Important features etc Hydrophytic Vegetation Present? Yes 181 No 0 Hydric Soil Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Yes 181 .No 0 Weiland Hydrology Present? Yes 181 No 0 Remarks: This pit is located on the southwest side of May Creek near fence posts. The hole was pre-exlsting -It appears it may be leftover from when the fence was Installed. VEGETATION -Use sCientific names of plan s Tree Stratum (Plot Size: 10m) ~ob~~~!~ 1. None 2. 3. 4. Sapling/Shrub stratum (Plot Size: 10m) 5. Spirea douglasii 6. 7. 8. 9. Herb Stratum (Plot Size: 5m ) 10. Pha/srls srundinacea 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Woody Vine Strat!Jm (Plot Size: 10m) 1. None 2. % Bare Ground in Herb Stratum 0 o 25 25 75 75 100 Dominant Species? = Total Cove~ .y = Total Cover Y = Total Cover = Total Cover Indicator Status FACW FACW Dominance Test Worksheet: Number of Dominant Species That Are OBl, FACW, or FAC: Total Number of Dominant Species Across Ali Strata: Percent of Dominant Species That Are OBl, FACW, or FAC: Prevalence Index worksheet: Total % Coyer of: DBl species FACW species FAC species FACU species UPl species 2 2 100 Multiply bv: x1 = x2= x3 = x4 = x5= (A) (B) (AlB) Column Totals: (A) (B) Prevalence Index = BtA = Hydrophytlc Vegetation Indicators: Yes Dominance Test is >50% Prevalence Index is ;::'3.01 Morphological Ada~tations 1 (Provide supporting data in Remarks or on a separate sheet) Wetland Non·Vascular Plants 1 Problematic Hydrophylic Vegetation 1 (Explain) 11ndicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytlc Vegetation Present? Yes No o Remarks: Some riparian plantings at edge of plot were recenUy Installed, and are too small to provide any coverage. We excluded those plantings from this plot. US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Valley· DNRP SOIL SamplinQ Point: #7 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type' Loc' Texture Remarks ---------0-2" Duff layer Mostly reed canarygrass roots 2 -18" 10 YR 3/2 80 5YR 5/8 20% C PL, M clay I I I 'Type: C= Concentration, O=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix Hydric Soli Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problemat ; HydriC SOils': 0 Histosal (A 1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 His!ic Epipedon (1\2) 0 Stripped Matrix (86) 0 Red Parent Malerial (TF2) I 0 Black His!ic (A3) 0 loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (S1) 0 Depleted Dark Surface (F7) 3'ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (S4) 0 Redox Depressions (Fa) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Solis Present? Ve. 181 No 0 I Remarks: I HYDROLOGY I Wetland Hydrology Indlestors: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A1) 0 Water-Stained Leaves (B9) 0 Water-Stained Leaves (89) 181 High Water Table (A2) (except MLRA 1, 2,4A, and 48) (MLRA 1. 2. 4A. and 48) I 181 Saturation (A3) 0 Salt Crust (811) 0 Drainage Patterns (810) 0 Water Marks (81) 0 Aquatic Invertebrates (B13) 0 Dry-Season Water Table (C2) 0 Sediment DepOSits (B2) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (Cg) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (B5) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aeriallrnagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (B8) Field Observations: I Surface Water Present? Ves 0 No 181 Depth (inches): Water Table Present? Ves 181 No 0 Depth (inches): 12' Saturation Present? Ve, 181 No 0 Depth (inches): surface Wetland Hydrology Present? Ve. 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: . I US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I ------------------- Photo 1: Typical May Valley flooding looking south from SE May Valley Road in central portion of study area (January 26,2010) Photo 3: Scrub-shrub portion of the wetland near Soil Pit #1 in southwestern quadrant ofthe study area (January 21 , 2010) May Creek Channel Restoration Wetland Delineation 29 Photo 2: Looking just east of an undeveloped portion of the wetland Avenue SE (January 21 ,2010) J r " ~I ~ ~ f~,' .~;.~~~. ~<:;. _\~~ ~ ~. ' .... -::;. f r # :.\.(1 ...:-~ .-<\ I~"" _ __. _ "-~M·.I'''' 'I..~ ~ ,.' '~~ .. ~., "-~ /. . ,~, .: ' .. ~' , ~. ~,~.~ . -----=, -., '\ "'.\ -• ~ '~ ~ .... ",'Ii ('I g ~ ~. C» I' \ II !l • I / I~/," . . '~~. ". ~ --' .' \. /l:" 'f:> , ~ -Photo 4 : Hydric soil at Soil Pit #4 in the northwestern quadrant of the study area (January 26, 2010) March 2010 ------------------- Photo 5 : Southern extent of the wetland near Soil Pit #3 in the southeastern quadrant of the study area (January 26 , 2010) Photo 7: May Creek in the eastern portion prolonged overbank flooding occur s (January May Creek Cha nnel Res toration Wetla nd Delineation 30 Photo 6: May Creek i n the central portion of study area where less overbank flooding occurs due to floodpla i n fill (January 21 ,2010) Photo Flooded pasture areas within the wetland in the central portion ofthe study area (January 21 , 2010) March 2010 ------------------- Photo 9: Hydric soil in Soil Pit #6 in the northwestern quadrant of the study area (February 24, 2010) Photo 11: Wetland area on the south side of May Creek on the west side of 148th Avenue 5E (March 1,2010) May Creek Channel Restoration Wetland D elineation 31 Photo 10: Fill area at the northwestern side of the study area outside the wetland boundary (February 24, 2010) Photo 12: Wetland boundary on the south side of May Creek on the west side of 148'" Avenue 5E where the blackberry begins to grow into the reed canarygrass (March 1,2010) March 2010 I:. _" May Creek Channel Restoration Project King County Water and Land Resources Division City of Renton Wetlan~itRating Addendum to Wetland Delineation Report Dated MeJrs,K'tOm9110 nrltng 0-_ .On III/Sian 4UG ~ 5 ' <VII ~~©~§W~ffJJ Prepared for: King County Department of Parks and Natural Resources Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 Prepared by: Cindy Clark, Environmental Engineer King County Road Services Division Environmental Unit November 17, 2010 CITY OF RENTON WETLAND RATING This document is an addendum to the May Creek Channel Restoration Project Wetland Delineation Report prepared by King County Road Services Division, Environmental Unit, dated March 10, 20 I O. The wetland delineation report described a large riverine wetland (total size approximately 140 acres) along a section of May Creek in southeastern King County near the cities of Renton and Newcastle. The project study area is located between River Mile (RM) 4.3 and 4.8 of May Creek, and included approximately 25 acres of the wetland complex (referred to as May Creek #5 in the King County Wetland Inventory (1990)). The purpose of the wetland delineation was to identifY the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. To determine the required buffer width, the wetland was also rated, using criteria referenced in the King County Critical Area Code (KCC 2IA.318). King County adopts the Washington State's Department of Ecology: Washington State Wetland Rating System for Western Washington (Hruby 2004). May Creek #5 was determined to be a Category 1I riverine wetland with a 110 foot buffer, located in the natural I OO-year floodplain of May Creek. However, the portion of the study area/wetland that lies west of 148 th Ave SE lies within the City of Renton jurisdiction, and therefore must also be classified using those criteria. The wetland, when rated using the City of Renton classification system, is a Category 3 wetland with a 25-foot buffer. The wetland is not a Category I wetland because it does not meet any of the following criteria: a. The presence o(species listed by the Federal or State government as . endangered or threatened, or the presence of essential habitat for those species; and/or b. Wetlands having forty percent (40%) to sixty percent (60%) permanent open water (in dispersed patches or otherwise) with two (2) or more vegetation classes; and/or c. Wetlands equal to or greater than ten (10) acres in size and having three (3) or more vegetatiori classes, one of which is open water; and/or d. The presence of plant associations of infrequent occurrence; or at the geographic limit of their occurrence The wetland is not a Category 2 wetland because it does not meet any of the following criteria: a. Wetlands that are not Category I or 3 wetland; and/or b. Wetlands that have heron rookeries or osprey nests, but are not Category I wetlands; and/or c. Wetlands of any size located at the headwaters of a watercourse, i.e., a wetland with a perennial or seasonal outflow channel, but with no defined influent channel, but are not Category I wetlands; and/or d. Wetlands having minimum existing evidence of human-related physical alteration such as diking, ditching or channelization 2 ... • The wetland is a Category 3 wetland because it meets criteria in (a): a, Wetlands that are severely disturbed, Severely disturbed wetlands are wetlands which meet the following criteria: 1, Are characterized by hydrologic isolation, human-related hydrologic alterations such as diking, ditching, channelization and/or outlet modification; and 2. Have soils alterations such as the presence of till, soil removal and/or compaction of soils; and 3. May have altered vegetation Criteria (b) and (c) under the Category 3 classification·include newly emerging wetlands and all other wetlands not classified as a Category 1 or 2. These are not applicable since criteria defined in (a) are met. The hydrology within the wetland is partly controlled by May Creek, which has been channelized in the past. On the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side qf the wetland, the wetland boundary more closely follows the natural valley topography. The wetland has also been deb'l'aded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. The wetland received a higher rating based on the King County and Washington State classification system, and has a larger buffer under that system (110 feet versus 25 feet with the City of Renton rating). The more conservative King County rating and buffer will be used when calculating project impacts and mitigation. 3 5 '. I I I I I I I I I I I I I I I I I I I EXHIBIT 12 BASELINE STREAM CONDITIONS MAY CREEK CHANNEL RESTORATION CIP#9A1205 April 15, 2010 ti King County Prepared by: Erick Thompson Environmental Scientist III and Kerry Bauman Environmental Scientist III Department of Transportation Roads Services Division Environmental Unit 20 I South Jackson Street, Suite 200 Seattle, Washington 98104 I I I I I I I I I I I I I I I I I I I Table of Contents I Summary .................................................................................................................. 1-3 2 Introduction .............................................................................................................. 2-5 3 Methods .................................................................................................................... 3-7 3.1 Literature Review ............................................................................................. 3-7 3.2 Field Methods .................................................................................................. 3-7 4 Existing Conditions .................................................................................................. 4-8 4.1 General Site Survey ........................................................................................ .4-8 4.2 Stream Habitat ............................................................................................... 4-11 4.3 Fish Habitat and Use ...................................................................................... 4-14 5 Discussion .............................................................................................................. 5-16 6 References .............................................................................................................. 6-17 List of Figures Figure I. Vicinity Map .................................................................................................... 2-6 Figure 2. May Creek Drainage Basin ............................................................................ .4-9 Figure 3. Stream Features ..................................................................... .4-14 Appendix A: Photos May Creek Channel Restoration Baseline Stream Conditions Page 1-2 1 Summary King County Department of Natural Resources and Parks proposes to dredge portions of May Creek in the May Valley to increase channel capacity and reduce flooding to adjacent pastures. The stream in this area is nearly flat and flows through large wetlands, many of which are currently used as pastures for horses. Historically, May Valley provided floodwater storage for tributaries draining the upper May Creek basin. Limited capacity to transport sediment through the flat valley allowed sediment to accumulate. Land owners periodically cleared the stream of sediment and in-channel plants until about the 1940's (King County 1995). Since then, development in the upper watershed to the north and south of May Valley has increased storm water run-off, leading to an increase in the frequency and duration, but not magnitude, of flooding in May Valley (King County 1995). Some infilling of the May Creek channel by fine sediment mobilized during flooding has probably contributed to increased flooding in the valley. Chronic winter flooding of some properties in May Valley limits the use of these properties for pasture and grazing of livestock, mostly horses. Stream baseline conditions were determined on about 853 meters (2,800 feet) of May Creek, beginning about 100 meters (328 feet) downstream of I 48th Ave SE, near river kilometer 7.0 (river mile 4.35), and ending near river kilometer 7.8 (river mile 4.87). In the proposed project area, May Creek flows through a flat, formerly ditched channel in an oversized valley formed by glacial meltwater (King County 1995). The valley is bordered on the north by Cougar and Squak mountains, which are underlain with bedrock, and on the south by the East Renton Plateau, which is formed by glacial deposits. The flat May Valley reach of May Creek stores stormwater and sediment, slowly releasing both to a steep, erosive canyon section downstream of the study reach, Slow water and abundant cover from overhanging vegetation in the study reach provide rearing and refuge habitat for coho salmon, cutthroat trout, and rainbow/steelhead trout. These fishes also use the mainstem creek as a migration corridor to spawning and rearing habitat in tributaries such as the North Fork, Cabbage Creek, Country Creek, and Tributary 0291 A. Stormwater and sediment storage in the valley also help maintain spawning and rearing habitat for salmon in May Canyon, located immediately downstream of May Valley. Five species of salmon are found in May Canyon: Chinook, sockeye, and coho salmon, and cutthroat and rainbow/steelhead trout (King County 1995). Puget Sound Chinook salmon and steelhead are listed as threatened under the Federal Endangered Species Act. If the proposed project requires a federal permit or has federal funding, then endangered species act consultation for Chinook salmon and steelhead will be necessary. May Creek Channel Restoration Baseline Stream Conditions Page 1-3 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Key Points: I. May Valley was historically an area of floodwater and sediment storage as the nearly flat stream braided through extensive wetlands. The channel was ditched between 1910 and 1936 for agriculture (King County 1995). The ditched channel filled with sediment and was dredged by King County in the 1940's to reduce flooding, and refilled with sediment again by the 1960's (King County 1995). Truck farming was taking place in the valley during this time, and agricultural fields were plowed right up to the top of the stream banks (King County 1995). 2. Current sediment sources to May Creek in May Valley have not been clearly identified. The May Creek Erosion Stabilization Draft Report (Anchor QEA, LLC 2110) only addresses erosion downstream of May Valley. It is unclear if flows in the flat valley reach have enough power to transport sediment the nearly two miles from upstream sources to the project area, and large sediment plumes from tributaries were not observed during site visits. Gravel transported to May Creek from Long Marsh Creek creates one of the few potential spawning areas within the project area, and did not appear to hinder water flow during the ·site visit. Severe erosion is present in a canyon reach below the project area (King County 1995, Anchor QEA 20 I 0). The May Creek Hydraulic Ana/ysis (King County 20 I 0) evaluated whether dredging in the valley would worsen erosion in the canyon. This analysis showed that there is no substantial difference between the erosion that occurs in the canyon under existing conditions and the erosion that would occur under any of the dredging alternatives. 3 .. Areas of the valley that are designated as open space, where flooding does not threaten homes or pastures, and where an intact woody riparian corridor exists provide pockets of refuge for rearing and migrating fish. Ifleft intact, these areas may provide refuge for fish affected by dredging in the valley. 4. The proposed project is one of four proposed "Insufficient Flow Projects" identified in the May Creek Drainage and Restoration Plan (GeoEngineers 2008). The four projects together would result in dredging of about 3.64 km (2.26 miles) of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. May Creek Channel Restoration Baseline Stream Conditions Page 1-4 2 Introduction King County Department of Natural Resources and Parks, Water and Land Resources Division (KC DNRP) proposes to remove sediment and in-channel plants from May Creek within May Valley to increase channel conveyance capacity and reduce flooding to adjacent pastures. A total of four "ineffective flow" channel clearing projects were proposed in the May Creek Drainage and Restoration Plan, totaling about 3.64 kilometers (2.26 miles, GeoEngineers 2008), which is about 75% of the total length of May Creek in May Valley, and about 32% of the total seven-mile length of May Creek. We studied existing conditions on about 853 meters (2,800 feet) of May Creek, beginning about" I 00 meters (328 feet) downstream of 148 th St, near river kilometer 7.0 (river mile 4.35), and ending near river kilometer 7.8 (river mile 4.87), and roughly corresponding to the area of May Creek identified in "Ineffective Flow Project #1" (GeoEngineers 2008, Figure I). Our study evaluates the suitability of the stream as fish habitat, and physical processes affecting the stream, stream channel, and stream inhabitants. Included in the study is a review of existing literature and information about May Creek, and a qualitative general site survey which evaluates the physical and biological characteristics of the channel and the surrounding areas. May Creek Channel Restoration Baseline Stream Conditions Page 2-5 I I I I I I I I I I I I I I I I I I I - M:,y Creek Channel Restoration Project Proj ect V icinity • Study Area o Mile Markers Stream Incorporated Areas • Cougar Mountain Wildland Par k ~ • N + March 2010 ttl King County o 95 190 380 570 760 •• ~ ........... _, •• Io_-.-.", IOrotC~.." .... ~ .... riIIt"""_."".,,,,joIdlo ................ IGooIc-.,...." •. ---..,. .. _ ....... _ .~.Io_"'-'''''''.----. • ..,. ........ _w-IN. ,.. ........... li0ii .......................... ,. ..... ~C __ .... IIOII ... I* ..... ,. .. _ ......... . ~ .. __ ...... _ .... I'iWI ...... _iotII ...... 1M .............. '-1_ ..... ,..... ......... _ ... ........... .... "" ........ ---.. ........ ",-. "", ... "'tNr_p .,IMo~ _11* IN, iii ,..hibiW .... ,.., ...... ,.n.II.KiooeC....ay. Figure 1 I I I I I I I I I I I I I I I I I I I 3 Methods 3.1 Literature Review We reviewed the following infonnation to identify natural drainage system features and provide background infonnation prior to field visits: • May Creek Current and Future Conditions Report, March 1995. King County Surface Water Management Division; • May Creek Basin Action Plan, April 2001. King County Department of Natural Resources, Water and Land Resources Division; • May Creek Drainage and Restoration Plan, December 2008. GeoEngineer; • May Creek Erosion Stabilization Draft Report, May Creek Sediment Transport Study Phase 3, January 2010. Anchor QEA, LLC; • Washington Department of Fisheries. 1975. A Catalogue of Streams and Salmon Utilization. Volume 1. Olympia, Washington; • Snyder et a!. 1973. Soil Survey of King County Area, Washington. Soil Conservation Service; • King County Sensitive Areas Map Folio. 1990. Maps 4 (Duwamish) and 9 (Issaquah). 3.2 Field Methods On February 1,2010 King County Roads Environmental Unit Senior Ecologists Erick Thompson and Kerry Bauman walked about 853 meters (2,800 feet) of May Creek, beginning about 1 00 meters (328 feet) downstream of 148 1h Ave SE, near river kilometer 7.0 (river mile 4.35), and proceeding upstream to the "red bam" at about river kilometer 7.8 (river mile 4.87, Figure I). We walked May Creek to visually characterize channel morphology, bank condition, substrate, in-stream aquatic habitat, large wood, and riparian plant communities and land-uses. We measured wetted channel width and depth in representative locations, but high water prevented identification ofbankful channel width and depth. We used field observations to characterize the present condition of the stream channel, including its suitability as fish habitat and its apparent conveyance capacity for water and sediment. We also noted any fish, other aquatic organisms, and wildlife or wildlife signs we noticed during the survey, and took photographs to provide a visual record (Appendix A). May Creek Channel Restoration Baseline Stream Conditions Page 3-7 4 Existing Conditions 4.1 General Site Survey The general site survey is qualitative, based on information obtained through review of existing background information and observations made during site visits. Results of the general site survey should not be viewed as a systematic, quantitative evaluation of the features described. . 4.1.1 Natural Drainage System May Creek is about 11.3 kilometers (seven miles) long, with about 30.6 km (19 miles) of tributary streams, draining about 38.3 square kilometers (14 square miles) in eastern King County (Figure 2, King County 1995). Three headwater creeks join at the top of May Valley to form the main channel, which flows through the valley and a narrow, erosive canyon before flowing into Lake Washington (Figure 2). The bedrock foothills of Cougar Mountain, Squak Mountain, and Newcastle Hills fonn the uplands north of May Valley, and a gently rolling plateau of glacial deposits (East Renton Plateau) forms the uplands south of May Valley (King County 1995). The valley itselfwas carved by glacial meltwater, and is underlain by 61 to 152 meters (200 to 500 feet) of unconsolidated glacial sediments (King County 1995). Tributaries descending through the glacial deposits of the plateau to the south and across the steep bluffs of the canyon are highly erosive and contribute large amounts of sediment to May Creek, whereas tributaries descending from the bedrock-underlain foothills to the north of May Valley are less erosive (King County 1995). May Valley was historically an area of sediment deposition and flood storage, and the stream channel braided through extensive wetlands. The stream was put in a ditched single-strand channel so the surrounding floodplain could be used for agriculture. Storm water storage in May Valley is important for controlling erosion in May Canyon, which is experiencing severe erosion in both the mainstem and tributaries (King County 200 I, Anchor QEA 20 10). Much of the sediment plume deposited by May Creek in Lake Washington is probably a result of canyon erosion, since sediment is stored in May Valley (King County 1995). May Creek Channel Restoration Baseline Stream Conditions Page 4-8 I I I I I I I I I I I I I I I I I I I Be ll eyue Newcastle Renton ,. w o ! ~ .. ~ Iq';NTON ~TEAU Bellenle Issaquah • ~ • May Creek Channel Restoration Project May Creek Basin • Study Area 0 River Mile /"--./ Streets /"--./ Streams 50 Foot Contours o May Creek Basin -Water Features Wetlands (NWI) Incorporated Areas • Cougar Mountain Wildland Park , N -(- March 2010 W King County o 900 1,800 3,600 5.400 The information induded on Ihismap has been compied by ~ng County statrfrom II variety of SOUfceS and is subjed to changewlhoul notice . !<ing Count y makes no representa1 ion s or w arranties, 8Jq?ress or implied , as to acruracy, completeness , tim.~nes., or nghts 10 the use of such information . This dowment is not ntended for use as a surve y produd . King County shall not be l iable br any general , special , m irect , ina dental , or consequent ial damage s indud ing , but nOllimited to , lost revenues or kist profits resuhing from the use or misuse of the information contai'1ed on this map. hly sale of this map or information on th is map is proh ibited exce pt by written permission of King Count y Figure 2 7 'D ""_.E!'D.e ...... __ I$\IiIlI»5 ... ,., ~e .u ,...t>_. (IIa era-_'c c; I I I I I I I I I I I I I I I I I I I 4.1.2 Riparian Land Use and Vegetation Small horse farms and open space are the primary land-uses in May Valley. Wetlands that have been converted to horse pastures border both sides of the stream in the project reach, except for the area downstream of I 48 th Ave SE, which is open-space associated with the Stonegate development (Figure 3). Reed canarygrass (Phalaris arundinaceae) is pervasive. Stands of willow (Salix spp.) and red alder (Alnus rubra) in the downstream portion of the project reach greatly improve the stream channel from a habitat and natural channel morphology perspective. These woody plants stabilize stream banks, provide shade, food, and hiding cover, and affect in-stream habitat by providing hard points that create a mixture of slow-water and fast water areas. The channel in the upstream portion of the project reach, which lacks woody plants and is almost exclusively vegetated with reed canarygrass, is more uniform and has filled in with sediment so it is more prone to flooding. Sources of this sediment are unclear. It may be deposited by tributaries and stored in the valley, or it may be eroded from surrounding horse pastures, deposited in the stream channel, and stored in the valley. Horse pastures in the vicinity of the filled-in channel sections slope toward the stream and are muddy throughout much of the year (Appendix A, Photos 42, 44, 56, 59, 64, 67). 4.1.3 Adjacent Wetlands Wetlands are present along May Creek through most of the project area. Many wetlands have been converted to horse pastures and will be described in more detail under separate cover. Dominant vegetation is reed canarygrass. We saw both resident and migratory waterfowl using the open water wetland on the south side of May Creek, including mallards (Anas platyrhynchos), American widgeon (A. Americana), and wood ducks (Aix sponsa). 4.1.4 Animal Habitat and Use May Creek and associated wetlands provide habitat for a wide variety of animal species. Although we did not see terrestrial wildlife during site visits, we can assume that the following species use habitats within the study area: deer, bobcat, coyote, raccoon, moles, voles, and mice, as well as waterfowl and songbirds. We saw two buck rubs on willows adjacent to the stream; one rub was downstream of the l48th Ave SE bridge, near RM 4.4, and one rub was upstream of the bridge, near RM 4.5. We saw both resident and migratory waterfowl in the open water wetland on the south side of May Creek near RM 4.75, including mallards, American widgeon, and wood ducks. Fish, salamanders, frogs, and crayfish, are probably present in aquatic habitats within the proposed project area. 4.1.5 Riparian Soils, Bank Stability, and Channel Morphology From our vantage on the streambanks, it looked as though the project reach of May Creek has two primary channel forms, which are dependent on the riparian plant community. In areas where willows are present and in contact with stream flow, the May Creek Channel Restoration Baseline Stream Conditions Page 4-10 channel form appears to be mostly forced pool rime. In areas where riparian vegetation consists of reed canarygrass or trees high on the banks, the channel form appears to be plane-bed. Both channel forms derive from past excavations and ditching for agriculture and sediment deposition. The channel gradient is flat throughout. The water was too high for us to see the banks in most locations. Where banks were visible, stability looked good. The King County Area Soils Survey maps soils in May Valley as mostly Alderwood and Bellingham soils. Alderwood soils formed in glacial deposits, and Bellingham soils formed in alluvium found mostly in depressions in glacial deposits (Snyder et al. 1973). We did not sample soil during site visits, but soils observed in soil pits during the wetland delineation will be described under separate cover. 4.2 Stream Habitat We could not wade most of the stream reach during the February 1,2010 survey because the water was too deep. Most observations and limited measurements were made while standing on the banks. In-stream habitat in the surveyed reach of May Creek is greatly influenced by riparian plant communities. Aquatic habitat is much more complex in places where the riparian corridor has woody plants, such as willows, actively engaged with the stream channel and connected floodplain. Overhanging or rooted willow branches or stems provide cover and hard points necessary for bedform complexity, producing both turbulent and non-turbulent flow areas, backwaters and rimes, and shade and nutrients during the summer (Appendix A, photos 9,12,14,23,25). Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel (Appendix A, Photos 4, 5,10, II, 13,47,50 to 58, 60, 61). We divided the surveyed portion of May Creek into four reaches based mostly on the nature of the riparian corridor (Figure 3). These reaches are described in greater detail below. Reach One: Edge of forest (about RK 6.97 [RM 4.33}) to 148'h Ave SE bridge (about RK 7.18 [RM 4.46]). The effect of riparian plant communities is pronounced in Reach One. Most ofthe reach has a mature willow-dominated riparian' corridor, with reed canarygrass dominating the understory. Abundant lichens grow on willows, suggesting they've been there awhile. Wetted channel width is 10 to 15 m (32 to 49 ft). Substrate consists mostly of fine-grained sand and silt, but some small gravels (2 to 5-cm [I to 2- inch 1 size) are exposed in fast water areas. As described above, overhanging and rooted willow branches and stems provide cover and hard points to create complex in-stream aquatic habitat. Water is clear and cold. The mixture of slow water and fast water habitats and abundant cover provide good rearing habitat for coho salmon and trout. We also saw a buck rub on a willow in this reach (Appendix A, Photo 8). The channel is well connected with its floodplain, and the reach provides good flood storage. May Creek Channel Restoration Baseline Stream Conditions Page 4-11 I I I I I I I I I I I I I I I I I I I May Creek Channel Restoration Project Stream Features • Study Area o River Mile A/ Streets A/ Streams Incorporated Areas Cougar Mountain Wildland Park ... N -i- March 2010 ~ King County O;. .. ro .... '2~O======~=-O ....... ~~O======~;O • Feet The information induded on th is map has been compiled by !<jng County staffftom a variety 0( soureas and i s subjed to change w~hout notee. !<jng County makes no representations orwarrantiu, expres s Of implied, as 10 aCC1Jracy. completeness, timeliness , or rights to the use of such information . Th is dOQJrnent is not mended fot use as a survey product . King Countr shin not be liable for any general , speci." ndirect, madental, or consequent ial damages induding. but not limited to ,lost revenues or lost profits resulting from the use or misuse oflhe information confaned on thi s map. hly sale of this map or information on this map is prohibited except by vmtten permission of King County. Figure 3 'D M._acoog"el"' ..... I1IfI' ...... Wo\.':D5 .0M" __ Cu. 110.-._. ~.~_'Ge I I I I I I I I I I I I I I I I I I I Interspersed among the willow-dominated areas are a few stretches of stream with no woody riparian plants (Figure 3). The riparian corridor in these areas is dominated by reed canarygrass. Flow is uniformly slow and deep, with deep accumulations of fine sediment. Wetted width is about 4 m (13 ft), wetted depth is about 1.5 m (4.9 ft), and fine sediment accumulation is about 0.5 m (1.6 ft). These stretches of stream are less structurally complex than the willow-dominated areas, and reed canarygrass is the primary influence on in-stream fish habitat. Although reed canarygrass-dominated slow water, uniform, channels provide limited habitat for most species of salmonids, these areas do provide good rearing habitat for coho salmon fry because the grass slows the water current and provides hiding cover and shade. The channel becomes wider and shallower, and accumulations of fine sediment disappear near the entrance to the forested riparian corridor (Figure 3). Wetted channel width is about 5.8 m (19 ft), wetted depth is about 0.5 m (1.6 ft), and 2 to 5-cm (I to 3- inch) clean, loose gravels dominate the substrate, with some cobbles present along the channel edges. Red alder, willows, Indian plum, sword fern, and reed canarygrass are dominant riparian vegetation. The forested reach may provide some spawning habitat for coho salmon and trout, as well as rearing habitat. We observed Greenes Creek during a second site visit on March 1,2010, when the May Creek stream level was substantially lower than on the February 1,2010 (Appendix A, Photo 6). Greenes Creek flows from the East Renton Plateau toward the left (south) bank of May Creek at about RKM 7.0 (RM 4.4, Figure 3). The creek did not enter May Creek at the time of the site visit, but instead dissipated and infiltrated in the adjacent wetland (Appendix A, photo 7). We saw no sediment deposition from Greenes Creek in either the wetland or in May Creek. Reach Two: 148 th Ave SE bridge (about Rkm 7.8 [RM 4.46]) upstream to Fence line (about RK 7.3 [RM 4.55]). This reach has a relatively wide, mature willow-dominated riparian corridor. In-stream habitat is mixed riffle and glides or pools. Substrate is dominated by accumulations of fine sediments. This reach is well-connected with its floodplain. We observed evidence of recent overbank flooding and flood storage in the riparian corridor. We saw a second buck rub on a willow in this reach (Appendix A, Photo 26). Reach Three: Fenceline (about RK 7.3 [RM 4.55]) upstream to End of woody riparian corridor (about RK 7.6 [RM 4.7]). Willows are absent and the mature red alder- dominated riparian corridor is much narrower, about three meters (lOft) wide, in Reach Three. Reed canarygrass dominates the understory, and horse pastures are present on both sides of the stream. The wetted channel width is about 6.4 m (21 ft) and the wetted depth is about 0.9 m (3.0 ft), substrate is mostly fine sediment. The horse pasture on the right bank is about a meter (3 to 4 ft) above the current water surface, suggesting that the channel in this reach is currently large enough to transport higher flows than those present during our survey (Appendix A, Photo 44). The increased channel capacity in May Creek Channel Restoration Baseline Stream Conditions Page 4-13 this area is likely a result of sediment that was removed by King County in 2002 as part of a channel obstruction removal pilot project. Long Marsh Creek enters May Creek on the right bank at about RK 7.44 (RM 4.62, Figure 3). This tributary is a source of gravels to May Creek and there is about a 20 m (65 ft) section of stream with spawning-sized gravels around the stream confluence (Appendix A, Photos 30, 32, 37, 38). Reach Four. End of woody riparian corridor (about RK 7.6 [RM 4.7]) to Red Barn (about RK 7.9 [RM 4.9]). The riparian corridor in Reach Four consists almost entirely of reed canarygrass. The channel is straight, narrow, and deep, and has less capacity to contain water than the other reaches. Wetted channel width is about 4m (13 ft), wetted depth is about l.3m (4.3 ft), and fine sediment deposited on the channel bottom is 0.3 to 0.5m (I to 1.6 ft) deep. During the February I, 2010 site visit, pastures on both banks of the stream were flooded. It was not clear whether the flooding was entirely a result of overbank flow from May Creek, or whether a combination of overbank flow and high groundwater level. It appears that the valley slopes slightly to the north in the study area. Water from the flooded pasture on the left bank was flowing into May Creek at the time of our . survey, and overbank flow from May Creek seemed to be flooding the pasture on the right bank (Appendix A, Photo 48). It was difficult for us to identify the May Creek channel in some of the flooded areas, and we could not find the confluence ofindian Meadow Creek, so we were unable to evaluate sediment inputs from this tributary. It also looked as though erosion from muddy horse pastures upslope of May Creek may possibly contribute some sediment to the stream. During a follow-up site visit on March I, 20 lOwe were able to identify the Indian Meadow Creek confluence with May Creek (Appendix A, Photos 63 to 68). This stream drains Grand Ridge on the north side of May Valley and is piped and channelized along a private driveway before entering the right bank of May Creek at about RKM 7.85 (4.88, Figure 3). Substrate in the flat, unpiped portions of this stream consisted of spawning- sized gravels that are routinely removed from the channel prior to reaching May Creek (Appendix A, Photos 64, 65, 67). A small deposit of fine sediment from Indian Meadow Creek is present in May Creek at the confluence, but the sediment does not appear to have much effect on the channel's capacity to contain flow. 4.3 Fish Habitat and Use May Creek historically was an important salmon stream in the Lake Washington Basin (WDF 1975). The stream supported five species of salmon ids: Chinook (Oncorhyncus Tschawytscha), sockeye (0. nerka), and coho (0. kisutch) salmon, and rainbow/steelhead (0. mykiss) and cutthroat (0. clarki) trout (King County 1995). Salmon still use the stream and its tributaries even though their numbers have decreased (King County 1995). Chinook and sockeye salmon are found in the lower reaches of May Creek May Creek Channel Restoration . Baseline Stream Conditions Page 4-14 I I I I I I I I I I I I I I I I I I I I 'I I I I , I I I I I I I I I I I I I I and in May Canyon; they most likely do not travel upstream as far as May Valley (King County 1995). Coho salmon and rainbow/steelhead and cutthroat trout rear in May Valley and use it as a travel corridor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 0291 A (King County 1995). Stormwater stored in May Valley helps maintain spawning and rearing habitat downstream, especially in May Canyon. Floodwaters stored in the valley are released slowly and are thus less likely to scour redds in spawning beds in the canyon. Slow release of stormwater from the valley also probably decreases the potential erosion of canyon walls from storm flows. May Creek is located in Watershed Resource Inventory Area (WRIA) 8: Lake Washington Basin. It is a King County Critical Areas Ordinance Class F (fish present) stream, with 50.3 m (I 65-ft) regulatory buffers. Puget Sound Chinook salmon and steelhead are listed as threatened under the Federal Endangered Species Act. May Creek Channel Restoration Baseline Stream Conditions Page 4-15 5 Discussion May Valley has historically been an area of floodwater and sediment storage. The nearly flat stream historically braided through extensive wetlands. The channel was ditched between 1910 and 1936 for agriculture (King County 1995). The ditched channel filled with sediment and was dredged by King County in the 1940's to reduce flooding, and refilled with sediment again by the 1960's (King County 1995). Heavy truck farming was taking place in the valley during this time, and agricultural fields were plowed right up to the top of the stream banks (King County 1995). Sediment sources to May Creek in May Valley have not been clearly identified. The May Creek Erosion Stabilization Draft Report (Anchor QEA, LLC 2010) only addresses erosion downstream of May Valley. The flat valley reach may not have enough power to transport sediment nearly two miles from upstream sources to the project area, and large sediment plumes from tributaries were not observed during site visits. Gravel transported to May Creek from Long Marsh Creek creates one of the few potential spawning areas within the project area, and did not appear to hinder water flow during the site visit. Gravels in Indian Meadow Creek that are removed from the channel before they reach May Creek could provide additional spawning habitat. While erosion in the May Canyon is an ongoing problem, the May Creek Hydraulic Study (King County 2010), which evaluates several alternatives for dredging in the valley, shows that there is no substantial difference in the erosion that occurs in the canyon under existing conditions and erosion that would occur under any of the proposed dredging alternatives. If dredging is proposed in areas of the valley that are designated as open space, where flooding does not threaten homes or pastures, and where an intact woody riparian corridor provides better fish habitat, mitigation would likely be required to offset the negative affects that the dredging would have on fish habitat. These existing areas may provide pockets of refuge for rearing and migrating fish, and may provide such refuge for fish affected by dredging in the valley. The proposed project is one of four proposed "Insufficient Flow Projects" identified in the May Creek Drainage and Restoration Plan (GeoEngineers 2008). The four projects together would result in the dredging of about 3.64 km (2.26 miles) of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. May Creek Channel Restoration Baseline Stream Conditions Page 5-16 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -------------------------- 6 References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. King County 1990. Sensitive Areas Map Folio. King County. 1995. May Creek Current and Future Conditions Report. King County. 2001. Final Adopted May Creek Basin Action Plan. King County. 2010. May Creek Hydraulic Study (Draft). Snyder, D.E., P.S. Gale, and R.F. Pringle. United States Department of Agriculture, Soil Conservation Service. 1973. Soil Survey, King County Area, Washington, Sheet Number 5. .Washington Department of Fisheries. 1975. A Catalogue of Streams and Salmon Utilization. Volume 1. Olympia, Washington. May Creek Channel Restoration Baseline Stream Conditions Page 6-17 I I I I I I I I I I I I I I I I I I I Appendix A . May Creek Channel Restoration photograph log . Photo perspective is looking upstream unless otherwise noted. Left bank is on the left side when facing downstream . Photo I. Entrance to forest at downstream end of survey; perspective is looking downstream. Photo 2. Cobbles in forested area. Photo 3. Perspective is looking downstream . Photo 4. No woody riparian plants. Photo 5. Photo 6. Greenes Creek . Photo 7. Greenes Creek. No surface flow to May Creek but greener grass probably marks subsurface route . Photo 8. Buck rub on willow. Photo 9 . Photo 10. Perspective is looking downstream . Photo II . Photo 12. Willows provide cover and in-stream structure . I I I I I I I I I I I I I I I I I I I I I I I I I Photo 13 . Photo 16 . Newly planted spruce on left bank open space property. I I I I I Photo 14 . Photo 17 . I I I I I Photo 15. Photo 18 . Ponded water downstream of I I 48 th Ave S E bridge. I I Photo 19. 148 th Ave S E bridge . Photo 20. I 48 th Ave SE. Photo 21. Looking downstream under 14s'h Ave S E bridge. Photo 22. Upstream of 148 th Ave SE bridge . Photo 23. Photo 24. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 25. Photo 26. Another buck rub on willows . Photo 27 . Photo 28 . Photo 29. Photo 30 . Confluence of Long Marsh Creek. Photo 3 I . Footbridge over May Creek near Long Marsh Creek. Photo 32. Looking upstream at Long Marsh Creek confluence. Gravels at confluence. Photo 33. Photo 34. Photo 35. Photo 36. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 37 . Long Marsh Creek, looking up th e channel from May Creek. Photo 38 . Looking down May Creek from Long Marsh Creek. Photo 39. Narrow a lder riparian corridor up s trea m of Long Mars h Creek confluence. Photo 40 . Right bank armor. Photo 41. Photo 42. Pasture on left bank. Photo 43 . View of right bank . Photo 44. Horse in right bank pasture . Photo 45 . Flooded left bank pasture. Photo 46 . End of woody riparian corridor. Photo 47 . Photo 48. Flooded left bank pasture flowing into May Creek . I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 49. Flooding adjacent to May Creek . Photo 50 . Looking upstream toward Red Bam . Photo 51. Looking downstream . Photo 52. Flooding along both banks of May Creek. Photo 53. Photo 54. Flooded pasture near Red Bam. Photo 55. Photo 56. May Creek channel near Red Bam. Photo 57. Photo 58. Looking downstream from near Red Bam. Photo 59. Muddy pasture on left bank. Photo 60. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 61. Photo 62. Red Barn driveway bridge across May Creek, looking south. 2/1/10. Photo 63. Looking toward May Creek on 3/1110 . Indian Meadows Creek is in ditch. Photo 64. Indian Meadows Creek culvert outlet. Excavated gravels are piled on banks. Photo 65. Indian Meadows Creek culvert outlet. Photo 66. Indian Meadows Creek looking toward May Creek. All gravels are deposited in this reach. Photo 67 . Indian Meadows Creek, looking upstream from May Creek. All gravels are deposited in short reach indicated by arrow. Stream substrate is fines below lower culvert. Photo 68. Confluence of Indian Meadows Creek with May Creek, 311110. Minimal sediment deposition at confluence: May Creek is more than a meter (3 ft) deep . I I I I I I I I I I I I I I I I I I I Gerald Wasser From: Sent: To: Subject: Mr. Wasser, urban separator [urbanseparator@hotmail.comj Friday, September 09, 2011 2:27 PM Gerald Wasser May Creek Dredging ProjecULUA11-065, V-H, SP EXHIBIT 13 I respectfully request that the City of Renton deny King County a "Special Permit for Grade/Fill and a Critical Area Variance". The project is in a critical area, The downstream area that this project may potentially negatively impact is also a critical area! The downstream area was prezoned one dwelling per acre and declared an urban separator for good reasons: the presence of May Creek, and erosion and flooding in this area of May Creek. Both the County and the City recognize this urban separator designation. As Alex Pietsch once said, the City received more input regarding creating the May Valley Urban Separator than they did for the whole Boeing rezone. Our community has lived by May Creek and along side the steep slopes of the ravine that surround May Creek for many years. We know the sensitivity of this environmentally critical area. We have supported its protection amid concerns for the landscape and negative impacts to our own lives. We care deeply about our environmentally sensitive area. In fact, we gave up the potential economic gain of higher dwelling density by supporting the urban separator concept. We believe this project will exacerbate downstream flooding and erosion. As a community, we have been communicating these serious concerns to all agencies involved since May 2010. As a result, the county has revised the project several times. Nevertheless;it is still not good enough. To address concerns, the Washington State Department of Ecology sent a hydro-geologist to site visit the downstream properties. Doctor Patricia Olson, the sole departmental hydro-geologist for all of Washington State, typically reviews much larger scaled projects. In her report dated August 15th , 2011, she questioned, among other things, the very effectiveness of the project and erosion and sedimentation thresholds values assumed downstream. Subsequently, on September 1st, 2011 state Ecology notified the county that the proposed project is lacking and Ecology will deny the permits if not revised. I urge the City of Renton staff and hearing examiner to request Dr. Olson's memo and Ecology's letter directly. We ask that the City of Renton deny the permits requested by King County and support its own citizens in assuring that this project will not increase flooding and erosion downstream. We have new erosion pins placed in February 2010 and a new stream gauge (37H) in place in the center of the downstream properties. Monitoring these erosion pins and gauge for 1 water year with above average rainfall would enable a better understanding when erosion occurs in our community. We ask the City of Renton to support its' citizens and require this monitoring before this project is allowed to proceed. Thank you, Jean Rollins 1 Gerald Wasser From: Sent: To: Subject: Attachments: Hello Mr. Wasser: --------------------------------------- A DUFFUS [klassicars@hotmail.comj Friday, September 09, 2011 11 :35 AM Gerald Wasser EXHIBIT 14 May Creek Drainage Improvement Project LUA 11-065, V-H, SP Cityof rentoncomments090911.doc; FINAL May 5 -May Creek Summary 05251 O.doc; May Creek residence sandbagged.jpg; May Valley Pasture Storm 2010.jpg; Trees & property lost FOREVER.jpg; May Valley Temporary Pasture Flooding Storm 201 O.jpg; Home in Peril.jpg Attached please find my comments and question regarding this King County dredging proposal. Depending on how it goes I may send the photograph attachments to my letter separately. Also the Meeting Notes from the Office of Regulatory Assistance. (ORA) Thank you, Andrew Duffus p.s. looks like everything uploaded fine. Should be one letter, one meeting's notes ORA and five (5) photographs. 1 ,------------------------------------------------ 2905 Ilwaco NE Renton, WA 98059-3764 September 9th, 20 II Gerald Wasser, Associate Planner Department of Community & Econorrllc Development City of Renton Renton City Hall lOSS South Grady Way Renton, W A 98057 VIAE-MAIL RE: May Creek Drainage Improvement Project ILUAII-065, V-H.SP Dear Mr. Wasser: King County Water & Land Resources Division proposes to dredge and/or remove reed canary grass and native willows between river mile 4.3 and 4.9 on May Creek. The goal of this ill-conceived project is an attempt to improve drainage on three horse pastures that are located within a wetland. Many downstream property owners, (all citizens of Renton) are apprehensive that this proposal may exacerbate stream flow velocity, volume and peak flow timing during storm events. (Footnote I) There are severe and well documented flooding and erosion issues downstream that put our homes, properties and sole access bridges in peril. (please see photographs attached.) Due to easement restrictions and development patterns, there is no way to access our properties other than private bridges across the creek. Recently the Washington State Department of Ecology conducted a review of the downstream issues. Their conclusion was that King County's project failed to provide the appropriate level of detail for potential downstream impacts. While we are less concerned about the removal of non-native invasive vegetation and replacement with native species suitable for stream bank stabilization and fish habitat, we are very concerned with the proposal to dredge, which we believe, will increase downstream flow during storm events. We are not isolated. Many of our concerns were echoed in an inter-agency meeting for the proposed project held on May 5, 20 I O. (See attached "Final Meeting Notes" ORA) Personnel from the City of Renton, two King County departments, the conservation district, state fisheries and ecology, the Muckleshoot Tribe and the U.S. Army Corps of Engineers attended this meeting. Several agencies expressed concern that this project was more about drainage of horse pastures than enhancement of May Creek and its associated wetlands. Questions asked regarded "buffers, repeated sedimentation, downstream impacts, inadequate mitigation," etc. During the past 16 months, the county has attempted to address some of those concerns. However, we do not believe that all issues are adequately resolved. As stated above the state Department of Ecology has recently concluded that King County's project failed to provide detail for potential downstream impacts .. I am reiterating some of the unanswered questions of downstream property owners and public agenCIes. 1. Proposed stream and wetland buffer width? 2. Timing of May Creek storm surge flows? ,--------------------------------- 3. Downstream bank erosion and destabilization of infrastructure? 4. Cumulative impacts of similar future proposed projects? 5. Ephemeral nature of this proposed project? First question, why is the county proposing only IS-foot mitigation buffers? My property straddles May Creek. When I applied for a permit to build a garage located over 300' (three hundred feet) from the creek, I was required to dedicate and publicly record a 165-foot conservation easement/buffer on both sides of the creek. A 15' buffer is considerably less than the 50 to 100 foot buffers that King County's own Code requires in rural areas. Further, within Renton city limits, Ordinance No. 5137 requires minimum 1 ~O-foot buffers for a class 2 stream. (Page 1025. a. I (a)) Even by administrative reduction the minimum requirement is 75 feet. WHY ONLY 15 FOOT BUFFERS? Second question, will peak storm flow timing be altered post-project? Any alterations of upstream conditions in either the May Creek channel, wetlands, natural floodplain or any of the tributaries (i.e. Long Marsh Creek) may have significant adverse impacts on the timing of peak flows·through the valley, the canyon and the creek's mouth at Lake Washington. The relationship between flow, velocity and timing of storm impulses and the role of the upstream May Valley wetlands and tributaries is not addressed in any of the county's reports or the design of this proposed project. The "May Creek Current and Future Conditions Report" released in 1995 has an informative narrative and analysis of a storm event that occurred in1990. This analysis discusses the January 1990 storm and how the tributaries and valley wetlands influenced the timing of peak flows. (See pages 5-24 to 5- 30) The report states, "upper basin tributaries ... peaked long before the valley." While the storm was generally considered a I ~O-year storm, the storage and metering effect of May Valley reduced the flood flow at I 48 th Ave SE (a.k.a. Nile NE) andforther downstream to the range a/a 10-to 25-year flow. "While the tributaries peaked in the morning of the 9th during the heaviest rainfall, the main stem of May Creek did not peak until some 8 to 14 hours later. ... the large amount of valley floodplain storage resulted in a relatively small peak flow moving down through the valley at that time. A large portion of the flood volume was retained in the valley until the afternoon of the 9th , when floodwaters in May Valley began to recede .... The flood flow at I 48 th equaled that ... of a 10-to -25 year flood .... This spread out the time of peak or near-peak discharge in the canyon and at the mouth, rather than concentrating the flood volume with a consequent higher peak." (Page 5-26 MCC&FC Report) This begs the question, what are the post-project impacts on storm event timing relationships of May Creek, its tributaries, wetlands and floodplains and downstream erosion and flooding? Ifwe are going to remove natural wetland/floodplain choke points (stormwater metering points) and/or "manage" sediment contributed by Long Marsh Creek, what will be the downstream impacts to storm flow intensity and timing? Conclusion, the downstream impacts of the storm (scary enough as they were in 1990) could have been much worse had the creek, tributaries and wetland not interacted as they did. Has the timing of flood events and flow rate post channel clearing/dredging been adequately addressed? Third question, what about erosion and destabilization of homes and bridges downstream? The threshold of sediment transport (i.e. erosion) affects the creek's banks (our property), infrastructure (homes and sole access bridges) and aquatic habitat. To support the proposed dredging project the county is relying, in part, on the May Creek Sediment Transport Study (KC 2010) and the Hydraulic and Hydrologic Analysis o[the May Creek Channel Restoration Project. (KC 2010) These studies use hydrologic simulation (HSP-F) and hydraulic model HEC-RAS. The number of data points in the Sediment Transport Study is limited because only three (3) flow-monitoring stations were established and one failed during the short 14-month study period. The County has attempted to make up for this lack of hard data by simulating hydrologic conditions. We are not comfortable with this as there have been acknowledged errors in previous modeling of May Creek. Further, as in most streams, all sediment is not created equal. There are different size particles in the various reaches of May Creek. Particle size sampling is required to validate any model or simulation. King County has many times acknowledged the downstream erosion and flooding problems. In 2007, the county hired the consulting firm of Anchor QEA, LLC to study sediment transport (erosion) and suggest ways to mitigate erosion and flooding of homes, bridges and properties. King County spent a great deal of money and staff time to work with the consultants to determine how to stabilize the banks of May Creek downstream of the proposed project. Ideas to reduce erosion and flooding of homes, loss of bridges, etc. included re-aligning the creek channel, shoring up the banks and/or the outright purchase of at-risk-properties. The downstream challenges are significant. Yet, to-date, King County has not proceeded with any of this mitigation. Instead, they are proposing an upstream project that may exacerbate downstream risks! . Between RM 3.8 and 4.0, the creek makes four 90-degree bends. At these bends, the creek banks are extremely unstable. Furthermore, over time the creek bed is armoring itself with larger and larger cobble thus flow is now impacting bank stability to a greater extend. The creek banks are eroding and migrating. This is not only imperiling at least one home but is most certainly causing loss of property and habitat through bank collapse. (This geomorphology was predicted in the "May Creek Sediment Transport Study". (See excerpt reproduced below [2]) We asked the county install more in-stream flow monitoring stations, gather more data and be absolutely certain that there will be no unintended negative consequences to downstream public and private properties, and stream habitat. On February 11th, 2011, King County Water and Land Resources (W&LR) completed the installation of six erosion-monitoring pins between River Mile 3.9 and RM 4.2 downstream of the proposed dredging project. Please note the stream bank erosion pins were installed on February II, 20 II. These were set sticking one-tenth (III Oth) of a foot out of the stream bank per King County email reproduced here. "> From: Tim.Kelly@kingcounty.gov > To: klassicars@hotmail.com ._--------------------------------------- > Date: Mon, 25 Apr 2011 12:12:57 -0700 > Subject: Emailing: Survey Notes for Andrew Duffus.pdf > > Hi Andrew, tried calling a few times but your number (425-255-xxxx) goes straight to a busy signal. I'll try and call again later today (and tomorrow if necessary), but if you get this just email me back so I know. The pins all look to be set around 0.1'." At the bottom of this correspondence are stream flow records [(3) from October 1st, 2010 to AprilSth, 2011. Notice the flow recorded on the second day of April 2011 -91.59 cubic feet per second. This writer examined three of the erosion monitoring pins on April 11th, 2011. Two of the pins were exposed over three-tenths (3/1 Oth) of a foot. This indicated over two-tenths (211 Oth) of a foot erosion between date of install and date of observation. The stream flow records at gauge site 37H show a maximum flow of 92 cubic feet per second between February 11 th, 2011 and the observation date, April 11 tho It is reasonable to conclude that erosion occurred at 92 cfs OR LESS!! In the past King County, or its consultants, have come up with various erosion thresholds. These theoretical thresholds have been determined by interpolation and modeling. The current estimate the county is using is 233 cubic feet per second. However, this estimate rests on a limited number of empirical observations. Recently we have seen with our own eyes that bank erosion has occurred at just 92 cfs or less. Through our lawyer, we have asked the county to delay this project until potential adverse impacts downstream can be evaluated. Now that the county has installed more stream flow gauges and erosion monitoring sites there is a wonderful opportunity to determine a refined erosion baseline and clearly .document that this proposed channel dredging will not create any unintended negative consequences downstream. Fourth question, what about cumulative impacts of similar future proposed projects? The May Creek Channel Restoration Baseline Stream Conditions (KC April IS, 2010) states, "The proposed project is one of four proposed "Ineffective Flow Projects" identified in the May Creek Drainage and Restoration Plan (GeoEngineers 2008). The four projects together would result in dredging of about 3.64 km (2.26 miles) of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length." (Page 1-4 MCCBRSC) The cumulative impacts orall these projects must be addressed now! Not piecemeal as each subsequent project is considered. Fifth question, what about the ephemeral nature of this proposed project? GeoEngineers, the authors of the May Creek Drainage and Restoration Plan (GeoEngineers 2008) stated: "The greatest challenge and limitation to IPF I (Ineffective Flow Project One) is the ephemeral nature of the solution proposed. While IFP I would be expected to immediately address flood duration, conveyance, fish passage, and other issues, the benefits would be expected to be short lived .... May Valley is naturally a sediment deposition zone, and as sediment sources in the ~---c----------------------------------- headwaters of the May Valley remain unmitigated, May Creek would be expected to fill back in." Before a lot of time, energy and money are spent, we ask that there is a concrete plan to address the otherwise ephemeral nature of the current proposal. MOREOVER, all the downstream impacts must be addressed! We are not saying that the project should not go forward. We are only saying that the county does not, at this time, have sufficient information to make this critical decision. We appreciate that the county has taken considerable time getting to this point. However, passage of time, by itself, does not fill in data gaps. As of today, data essential to making an informed decision is still missing. We ask that the City of Renton permit/variance decision be deferred to allow time to collect the necessary data and correlate the rainfall, stream flows and erosion in real time. Until this pear, there were no erosion monitoring stations in the reach oUlte creek tTrat contains {our (4) erosion prone 90 degree bends. Until the (all 0{2009 there was no {low meter in this reach oUTre creek either. With these additional erosion monitoring stations pins and the additional flow gauge, it is now possible to have real time data to establish the erosion threshold with greater certainty. This, in turn, will allow the permitting agencies to understand better how the additional volume and velocity post-project may, or may not, exacerbate downstream flooding and erosion. We are asking for more time to collect and analyze data based on current known conditions (not assumption, interpretations or hypothesis). We are requesting greater certainty for the downstream citizens. We deserve mitigation to reduce any significant impacts to our homes, property and bridges and habitat. The city must not issue the permit/variance until the Washington State Department of Ecology, other local state and federal agencies, tribes and the public (particularly the downstream property owners, all citizens of the City of Renton,) have had their questions and concerns adequately addressed by the applicant. Moreover, adequate mitigation be proposed downstream. The city has an obligation to look out for its citizen's best interests. This also applies to the public and private infrastructure and riparian habitat at the mouth of May Creek (i.e. Barbee Mills). In summary, our questions are threshold of sediment transport, cumulative impacts, timing of peak flows, the projects ephemeral nature and regulatory critical areas buffer widths. We are asking that your department review our concerns and ensure that the county's proposed project does not have any unintended negative consequences downstream within the City of Renton. As a downstream property owner, I request that the City of Renton defer the Special Permit for Grade/fill and Critical Areas Variance at this time. This will allow time to correlate rainfall data, stream flow and the recently established erosion monitoring pins. We must establish and better understand the actual threshold of erosion as it affects the downstream reach of May Creek. The proposed project is primarily about draining several upstream horse pastures located in a wetland. There is potential for significant downstream impacts to people's homes and sole access private bridges! We ask Renton to consider this application very carefully and hold King County accountable. Sincerely, Andrew Duffus cc: Mayor's Office, City of Renton FOOTNOTES: (1) There are seven properties adjacent to May Creek within River Mile 4.3 an 4.9, the proposed project reach. One of these properties is a dedicated open space wetland; the second is an undeveloped-unused property that is obviously a wetland; and the third is not used for farming activity of any kind. The remaining four properties do pasture horses. None of the homes on these properties is in danger of flooding. Converselv. between Nile Avenue NE and Coal Creek Parkway there are 18 homes along the creek and two sole access bridges. At least eight of these homes are within 30 to 50 feet of the unstable creek banks and/or close enough to experience flooding (2) The armoring of the streambed and subsequent erosion of the banks was predicted in the "May Creek Sediment Transports·Study", June 2009, Anchor QEA, LLC. Page 25 and 26 state the following: "The portion of May Creek examined in this study lacks an upstream sediment source for gravels and sands. As flow events impact the reach, the sediment size distribution along the channel bed will tend to coarsen over time; due to the transport of finer sediments out of the reach with no incoming sediment supply to replenish these materials. This armoring effect will tend to increase the threshold of sediment motion for the channel bed. On the other . hand, bank sediments, which are likely of finer gradation than the bed sediments, will remain unchanged and are not affected by a natural armoring effect. Therefore, future erosion events may be characterized by bank migration (movement ofthe stream channel from its current location) as opposed to channel incising." Writer's comments: Bank migration equals risk and peril for homes and bridges. So we are draining horse pastures in wetlands to increase seasonal use, while we run the risk of exacerbating downstream conditions that put at peril not only sole access to properties (bridges), but the actual properties themselves and the homes that people, --not horses --LIVE IN! (3) Site 37H -May Creek at 143 PI SE Stream Gauge(Recording) Select a different water year: 12011 3~ 2 .14261163729.2791.59 1 3 17.48 12.54! 15.25 29.09 4 .. 14.17 111 .17 ,15.8030.01 i 5 6 ; I I ' 1.50,14.26,11.56,13.4818.88 7 'i: 1.51 30.30 10.64 ,26.56 22.03 8 1.39 25.61 20.17 39.84 9 10 I I :-_; ::T:'---~--,----.wr-·-",,----"-- , 11 '11.53,11.70i 46.52 127.78:16.67158.52: i i ; I : i ~·--·----'"---4·"-~·---~-i --~-(----~-, --'~-r"'-__ W".,+.,_~ ··--i·-"--'·'-l·w ...... w--r---·r--··I-~ -i-'--~~ 12 ~564 ;1017i221~78i~60~.f~~9l4611 ~ ___ ~_ .. ~_+_ l __ ~--I 13 13.81 ; 9.03 1199.52,68.46121.12,46.59, ! I i I ! 1 1 •• __ • __ ••••••• _._ ••• ".". __ ....... • •••••••• •••••••••••••••• __ ••• ... ·-r-·"·"-_·········r····--····················y-··· .. · .. ·_ .... ···"·i·······,,· __ ·_····,,-_· .. ·'" ....... ,-..... ,,---j----"-',,"'''''''' ""-T" .--.' , --".-, i""".""" ,,--,---r .---..... .--...... ,,-,--+--_ .. ----., ..... 14 13.13,11.33,128.83171.90,25.21154.40, ! ! ! I i I f-, --15 _~.99J146~! 89.8916298!29.80f49.6~I ___ ! _. r1---1 ~ ___ ' ! 16 12.6315.67,64.71i68.11,26.27151.37, L...J I I , 17 2.36 :1608! 48.86 16 1.97!22.90'42.461 . iii I i 18 . __ t2.38 118.081 38.66151.1~0 36.48, ___ i _1.. ! L_1i f---! i I I I . ! I I ! 19 2.20 i 17.30,33.19 43.17j 17.33 35.69,; ! WASHINGTON STATE Governor's Office of Regulatory Assistance FINAL Meeting Notes May Creek Channel Restoration Agency Meeting May 5,2010 Location Purpose Department of Ecology, NWRO, 3190 160,n Avenue SE, Bellevue, WA 98008 Review and comment on the May Creek proposal submitted by King County Water and Land Resource Division (King WLRD). Comments provided in the summary below were prepared by the Governor's Office of Regulatory Assistance (ORA) and are intended to offer a general overview of the information presented during the meeting. Participating agency staff reviewed and provided comments for the Final Notes. Introduction King County Water and Land Resources Division (KC WLRD) presented a proposal for a channel restoration project in May Creek. The project description includes improving in-stream flow conditions and restoring a buffer of native riparian vegetation along segments of May Creek in May Valley between approximately river mile 4.3 and 4.9. The three primary components are: vegetation removal, sediment removal, and stream I wetland mitigation. Participants were provided the following information before the meeting primarily via the May Creek website (http://www.kingcounty.gov/environmentlwatersheds/cedar-river-lake-walmay- creek.aspx): • State Environmental Policy Act (SEPA) Checklist and Mitigated Determination of Non- significance (April 21, 2010). • Wetland Delineation Report (March 20 I 0). • Baseline Stream Conditions Report (April 2010). • Draft Hydraulics Report (April 20, 2010). • Draft JARP A (Joint Aquatic Resources Permit Application) and project plans (Note: not available on website). The meeting began with a question and answer session regarding the project. The second half of the meeting was conducted as an agency round table to identify issues of concern, clarify requirements, offer suggestions how to avoid and minimize impacts, and describe permits and permit conditions. At the conclusion of the meeting, KC WLRD submitted application packets to the US Army Corps of Engineers (Corps) and Ecology (ECY). Next Steps Identified during the meeting were three action items regarding the following topics: SEP A public comment period, reference materials, and a follow-up agency meeting. www.ora.wa.gov 360-407-7037' 800·917-0043 -----------------------------------------------------------, WASHINGTON STATE Governor's Office of Regulatory Assistance .. SEPA Public Comment Period -7 Several agencies (Muckleshoot Tribe at the meeting; WDFW, City of Renton, ECY after the meeting) commented that it appeared their agencies did not receive a SEP A notice for the project. -7 A request was made to reopen or extend the comment period, which closed on May 5th . Next Steps: KC WLRD will review the situation with their SEP A staff and report back their fmdings to the group. -7 Follow-up from KC WLRD after the meeting: After reviewing our records, King County has confirmed, that due to an administrative error, the SEP A notification did not get sent to the necessary agencies per WAC 197-ll-3409(2)(d) for the May Creek Channel Restoration Project. Therefore, King County has not officially issued SEP A for this project. King County will be issuing SEPAfor this project within the next 4 to 6 weeks. We are delaying the issuance to allow time to consider modifying the project description based on the feedback received at the May 5, 2010 meeting. We are sorry for any inconvenience that this may have caused and thank you for your ongoing assistance with this project. .. Reference Material(sl for Earlier Projects on May Creek. -7 A previous sediment removal project was conducted near the McFarland property in 2002. This was a small, pilot project by KC WLRD. -7 A planting project on the Colassurdo property was implemented in the fall of 1995. Next Steps: KC WLRD will review their files and forward information to the group regarding these two projects. The planting plan from circa 1995 may no longer be available in King County archives. King County is searching through their files to see if project files are still available. Next Steps: Agency staff participating in the meeting will review files to determine if they have information on these projects to share with the group. If they find relevant information, please distribute to the group. ORA can also assist with distribution. .. Agency meeting, -7 The Corps offered to review the proposal and offer design suggestions to reduced impacts on the aquatic environment. '. The Corps invited other agencies and tribes to participate in the review and comment process. The outcome could result in a substantial redesign to facilitate review under the standard Individual Permit (IP). Or suggestion for activities such simply planting in the buffer which would have a shorter review, potentially under a Nationwide Permit (NWP) 27. ECY would need to verifY the wetland delineation. www.ora.wa.gov 36_0_4_07_-_70_3_7_' _80_0._-9_1_;~_··_~~_-; __ • :_a_~s_~s_~~~~~~.~~~~o_v_··_l __ -··_·~_-~_y 2_5~_20_;_~_-~1I WASHINGTON STATE Governor's Office of Regulatory Assistance Meeting and suggestions could be provided within a 30-60 day window. (Note: this assumes staff availability within 30-60 days.) KC WLRD suggested that the technical experts wbo worked on the various reports (wetland, stream, and bydraulics studies) be available to answer questions for agency staff. Next Steps: KC WLRD will discuss to detennine if this is an approacb they would . like the agencies to pursue. If yes, KC WLRD will coordinate with the Corps. Agency Comments King COUlity Department of Development and Environmental Services (King DDES) Two pennit processes are possible for the project: Grading pennit as allowed alteration under tbe Critical Areas Code if considered Habitat Enhancement OR Grading pennit with a separate Alteration Exception / Reasonable Use Exception of Critical Area Code ifnot considered babitat eilhancement. ~ Habitat Eilhancement Project 7 After reviewing proposal, King DDES anticipates it would be able to pennit the project under this approacb. 7 Requirements: Demonstrate that project restores babitat fonning processes or directly restores babitat function and value. Restoration and eilhancement plans must be prepared by a qualified biologist OR all properties bave an approved King County Farm Management Plan (approved by KingDDES). Average review time 120 days after submittal of a complete application. ~ Alteration Exception 7 Includes a public conunent process. 7 Requires an alternative analysis, similar to tbe Corps 404(b)(1) analysis, to ensure minimal impacts. 7 Appealable decision. 7 Average processing time 4-6 months after submittal of complete application. 7 In general, this process is usually longer and more expensive for the applicant. www.ora.wa.goy , 360-407·7037' 800-917-0043 assistance@ora.wa.goY May 25. 2010 .... II fJ" 'j', } "I'P''':'- WASHINGTON STATE Governor's Office of Regulatory Assistance ~ Other Comments. ~ If the Corps requires a standard Individual Pennit (!P), King DDES would require the Alteration Exception process. Much of the infonnation the Corps would request of KC WLRD for the !P process would likely be similar to what King DDES would need to generate for the Alteration Exception application. ~ Buffers: no specific distance required to qualify for a habitat restoration process. The buffers must provide an improvement over existing conditions. Acceptable buffer widths vary by project. Mayor may not accept buffer widths in Farm Management Plans by the King Conservation District. Right now, most of May Creek does not have any effective buffers. King DDES would see planting buffers with appropriate native vegetation as an improvement to the existing conditions. Buffer plantings would need to be fenced. Overall, King DDES needs to see an improvement or net gain. King Conservation District (KCD) ~ Two properties in project area currently have Farm Management Plans. ~ Existing Fann Management Plans in project area generally try to achieve 25 ft buffers on average for pasture areas. However, one property has a fence that is grandfathered in at 15 ft as it was installed prior to 1990 (the Celigoy property). KCD generally promotes installing larger buffers but it doesn't work all the time. ~ Fann Management Plans are landowner driven. ~ Prepared under National Resource Conservation Service (NRCS) methodology. Plans are not public documents. However, property owners may grant pennission to release the plan to specified individuals. ~ Some of the fann land in the May Valley has recently gone through ownership changes . . Many of the new owners are interested in implementing Fann Management Plans. Implementing Plans often involves relationship building between the landowner and KCD. Renton ~ For the work within Renton City limits, project would most likely require: ~ Grading and Fill pennit. ~ Critical Area Ordinance (CAO) Pennit. Review will be required to detennine if project qualifies for an exemption or needs a variance. ~ Construction pennit. Land Use Examiner process used for GradinglFill pennit. Both the GradingIFiIl and CAO process require a public hearing. ~ Average time 8-10 weeks, assuming no appeals. ~ .•. .J .' .. / ... , ..... : WASHINGTON STATE Governor's Office of Regulatory Assistance ~ lfproject has only 280 cubic yards offill, then an Annual Grading License may be another option. ~ Renton offers a pre-application meeting to discuss the details and clarifY requirements. U.S. Army Corps of Engineers (Corps) ~ Corps considers the purpose and need for the project when determining which permit is appropriate. ~ As proposed, the purpose of the project appears to be "flood control" or "increased conveyance" with some habitat features incorporated in the design for mitigation. ~ The current proposal appears to contradict some of the recommendations for improving stream habitat and functions as presented in the Baseline Stream Conditions Report. ~ The project as proposed does not meet the terms and conditions of a NWP 27. ~ At this time, project appears it will require a standard Individual Permit (IP) where a range of off-and on-site alternatives will be considered. The off-site alternatives will likely address source control and sustainability of any proposed action. On-site alternatives will evaluate ways in which impacts to the aquatic environment could be reduced. ~ A 404(b )(1) Alternatives Analysis required for an IP. Different evaluation than is required under SEP A. Considers alternative with least impact to aquatic resources. ~ Public Notice period part of process. ~ Endangered Species Act (ESA) consultation required. ~ Cultural Resources Survey also required. ~ Threshold for an IP vs. an NWP is based on the ecosystem restoration. The values and functions of the stream are considered. ~ For example, a NWP 27 would consider sediment removal when the purpose is for improved habitat functions. ~ Timelines: (Note: "average" asswnes straight-forward project review without significant issues I concerns and project revisions.) ~ IP: 180 days to I year average based on submittal of a complete application. ~ NWP: usually shorter than for an IP but still 4-6 months on average. ESA and Cultural Resources still required for NWP . ., The ESA process for all projects has been averaging 71 days. Mucklesboot Tribe ~ Note: Some of the Corps permits processes include consultation with the Tribes. This is the case with the Corps IP. ~ The project needs to provide details about the proposed mitigation; how does the mitigation compensate for the amount of dredging? The details for the proposed wood are missing, www.ora.wa.gov 360407·7037' 800·917-0043 assistance@ora.wa.gov -.. -........ -. _. "II!I May 25,2010 iii ,------------------~-------------------------------------- WASHINGTON STATE Governor's Office of Regulatory Assistance including the sizes, numbers, and species. The project will result in a loss of rearing habitat (albeit due to reed canary grass) and will need mitigation. A 15 ft buffer is insufficient. There needs to be fencing and long term protection of the buffer. ~ The Muckleshoot Tribe will review how much mitigation is included and what is sufficient. ~ Reed canary grass: even though a non-native species, provides juvenile salmon rearing habitat particularly because it provides lower water velocities. ~ Mitigation and riparian buffer proposed for the project (15 ft) may not be adequate because it does not appear to fully mitigate the project impacts. ~ More information to evaluate impacts would be required. ~ Concerned about long term, repeated sedimentation and subsequent removal projects. One of the project reports mentioned three other sediment removal projects for a total of 2.6 miles of May Creek. Need more information if this is the case. Cumulative impact from·more dredging on this reach of the stream as well as other locations is a concern. ~ Also, questions about how removing sediment from May Valley will impact downstream flow, erosion, and fish habitat. W A Department of Fish and Wildlife (WDFW) ~ Project needs to demonstrate no net loss of habitat. ~ Planting plan required. Crucial for long term prevention of reed canary grass proliferation, which increases sediment continuing to accumulate in stream. ~ The wider the buffer width on the stream, the better. WDFW does not have specific buffer requirements. However, WDFW has buffer recommendation in Management Recommendation for WA Priority Habitats, Riparian (flt/p://wd(w. we govlhablripxsum.htm). ~ Stream Report, page 8 and II. Gravel from Long Marsh Creek is an important spawning habitat. Do not want to see gravel in this area of May Creek disturbed. Would be better to widen this area where Long Marsh Creek flows into May Creek. ~ Not meaning to speak for the Corps, but in trying to qualifY for a NWP, it is recommended to design the project without a flat channel profile by adding pools and large woody material. ~ Note: the WDFW application cannot accept a Hydraulic Project Approval (HPA) application until the SEP A process is complete. Ecology 401/ Coastal Zone Management (CZM) ~ The 40 I Certification status depends in part on what permit the Corps determines is appropriate for the project. ~ If project is a NWP, then a 401 mayor may not be required. ~ If IP from the Corps, then ECY will require an Individual 40 I and a CZM Consistency Determination. www.ora.wa.gov 360-407-7037' 800-917-0043 .-... ... -.. -..... - -.. -.... --.---.. --------... 6 assistance@ora.wa.gov I May 25, 2010 , ---------------------------------------------------------------- WASHINGTON STATE Governor's Office of Regulatory Assistance -7 Individual 40 I and CZM must be completed before Corps can issue lP. ~ Other comments: -7 Project needs to follow current ECY Storm water Management Manual for Western Washington. -7 If greater than I acre disturbed, ECY Construction Stormwater General Permit required. -7 Since the mitigation report is pending, not able to review in full at this time. Ecology Wetlands ~ Concerned about several inconsistencies between Baseline Stream Conditions Report and the proposal. For example: -7 The purpose of the project appears to be to provide stormwater conveyance rather than habitat restoration. -7 From ECY perspective, concerned that project will not meet goal to drain water from pastures such that pastures will be dJ;y earlier in the year. The high groundwater table in many of the pasture areas will keep the pastures wet. -7 At this point, ECY may not be able to approve application as proposed. -7 Concerned that adequate buffer widths have not been proposed based on Best Available Science (BAS). Proposed buffers for wetlands and the stream may not be effective. Ecology Water Quality (ECY WQ) ~. May Creek is on the state 303(d) list for Fecal Coliform. -7 Most of the sampling and data is from King County. ~ Because of this, ECY would like to see limiting of animal access to May Creek. ~ ECY WQ staff prefers 35 foot buffers. The proposed 15 foot buffers appear thin for preventing future sedimentation of the Creek. ~ ECY WQ staff prefers South side buffer to be wider than 15 feet since it provides the best shading which helps reduce summer temperatures in the Creek. ~ Stream morphology, such as a meanderiIig stream, provides benefits of reducing sedimentation and improving water quality. Realize there are limitations with private ownership and that this might counter the water conveyance objectives of the project. Channel meander might be considered for the improvements in the area south of 14Sth . www.ora.wa.gov 360407·7037·800·917 . .()043 ....... ..... _ .... -.. -_ ..... _. __ ....... _ ... _ .. r-... -.. -_ .. _._. ···_··_·--···-11 assistance@ora.wa.gov I May 25, 2010 WASHINGTON STATE Governor's Office of Regulatory Assistance Attendees (per sign-in sheet) ~. Zelma Zieman, ORA ~ Jane Dewell, ORA ~ Doug Chin, KC WLRD ~ Rachel Berryessa, KC WLRD ~ Don Althauser, KC WLRD ~ Curt Crawford, KC WLRD ~ Lindsey Miller, KC WLRD ~ Randy Sandin, King DDES ~ Jamie Hartley, King DDES ~ Karen Walter, Muckleshoot Indian Tribe Fisheries ~ Larry Fisher, WDFW ~ Jay Mirro, KCD ~ Jennifer Henning, Renton ~ Ron Straka, Renton ~ Lori Lull, Corps ~ Matt Bennett, Corps ~ Rebekah Padgett, ECY 40 IICZM ~ Paul Anderson, ECY Wetlands ~ Patrick McGraner, ECY Wetlands ~ Dave Garland, ECY WQ ~ Chris Coffin, ECY WQ www.ora.wa.goy 360407·7037' BOO-917"'()043 assistance@ora.wa.gov May 25, 201011 r .. ~ I 'l .. - , ~ , l: • '. ; ., r . ' • ,":I" " . I " . I. ". , . • r , . . ... ~. .. , ~ I ~ ~~~ , . ~ . . , . . .. . . ", t .;. .' ' ... /I" . -. ... ' : .,_ ~ I, ~. ' . ' -:t. J I~ • • • ~' J, J • ... '" . r~ \.. I' ~\ ... -I l ,I' ~-' f ' -, , , ' • r , ., , ... ' .. • ... , t-"':;-. ~" .. " ...... ... ~ • ,;--. -'''(!)'b 1. • ¥- ~ • ~, " ~-, '. "-J \ ~ • .~. .,. , "'4 " ,\ " -, '~." , . tt t :,' , ' ~ ~ .. , " , ~ I , ", " • I ( , • I, I ' , ~ , 1 1 . L~' 'iJ.~ I l" I I' I ' , . i, ' r" j, I ~ t , I I 1 h t , I ' , " ; , ,.." \ . ' .......• A, I. • r' .. .. ,~~ , , ," i t' J" , f I f I , • f '. • • J Gerald Wasser From: Sent: , To: Subject: Attachments: Hello, A DUFFUS [klassicars@hotmail.com] Wednesday, September 14, 20113:16 PM Gerald Wasser May Creek Dredging EcyOlsonquestions.pdf; EcytoKC9111.pdf EXHIBIT 15 Attached is a recent memo from Dr. Patricia Olson of Washington State Department of Ecology. She questions the county's proposal to dredge a section of May Creek Also, attached is a formal letter from Ecology regarding the county's application for a Section 401 Water Quality Certificate and determination of Coastal Zone Management Consistency. These validate downstream property owners' concerns. Thanks for your support. Andrew Duffus 1 .-----------------------------------------------------------------------------~ Memo Page 1 To: Rebekah Padgett, 401 Coordinator, SEA-NWRO From: Patricia L. Olson, Senior Hydrogeologist, PhD, LHG, SEA-HQ cc: Patrick McGraner, Erik Stockdale Date.: August 15, 2011 Re: Comments on Upper May Creek dredging project My comments are mostly based on observations from our field visit on 07/29/2011 supplemented by technical documents provided by King County. I also reviewed comments from USCOE, Muckleshoot Tribe, and downstream.property owners but did not include in my discussions. I have many comments on the King County documents. But I have limited time so this memo contains only a summary of some important issues. 401 certification and WQ issues The King County memo from Julia Tumey to Doug Chen dated 2/11/2011 discusses how the project will increase the channels fine sediment transport efficiency within the project area (pp 14). The memo also states that fine sediment and organic material will be transported downstream at a constant rate rather than an episodic rate (pp 15) and sediment delivery to May Creek will be reduced "in the project area". This will be a change in the current sediment transport regime and current downstream effects from the fine sediment transport Since lower flows will be transporting sediment, the fine sediment will likely be deposited in areas upstream of where high, episodic flows would deposit the sediment However, the memo does not address what sediment volumes will be transported and where fine sediment will be deposited downstream other than to say it won't be Lake Washington. While the memo says that the project will decrease the agricultural sediment source at some time in the future, it does not say how long the increased sediment load will occur. The memo states that quantitative sediment estimates are not available (pp 16). These factors present ambiguities in terms of water quality effects. Dredging The project seems somewhat short-sighted because one time dredging will not solve the flooding extent and duration over time. LiDAR data indicate that there are large floodplain areas below the channel elevation (Figure 1). Some of this is may be due to LiDAR processing for the bare earth OEM. However, the Hand H study supports this conclusion (pp 19). The "flood basin" type landform may be a natural condition or it may be due to years of dredging and lowering groundwater levels which promotes subsidence in organic rich soils (e.g. hydric and peat soils). Wetland drainage leads to oxidation of the upper organic horizon burning up organic component The weight of livestock and machinery will increase the compaction and subsidence as well (e.g. Devin and others 1999). The survey notes that accompany the General Land Office (GLO) maps shown in the Turney memo indicate that the upper basin was mostly a groundwater fed wetland system. These conditions suggest that dredging is somewhat akin to trying to channelize a bathtub where water inflow is greater than outflow. Cost-benefit There may be a cost-benefit analysis but I haven't found it There" should be cost-benefit analysis of various options including removing backwater effects caused by bridges, reducing reed canary grass, reducing or eliminating fine sediment sources, and removing willows and replanting with vegetation that was documented to occur in the area including cottonwood, ash, maple, cedar and undergrowth species such as alder, native Pacific crabapple (Malus fusca), and vine maple. Backwater effects Backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge. The FEMA longitudinal profile indicates that backwater likely occurs at floods less than the 10-year flood. The King County Hydraulic and Hydrologic, Analyses of the May Creek, Channel Restoration Projec~ 12/17/2010 (hereafter referred to as the Hand H study) includes measured water surface profiles that include the footbridge. Table 1, pp 4-5 shows the footbridge location as river mile 4.612. Figure 3, pp 19 shows the water surface elevations measured on 01/08/2009 and 01/22/2009. The measured water surface profiles just upstream of the bridge show the backwater effect However, the documents ignore this effect For example, on pp 31, of the Hand H study, a description of gravel bar and flooding is given: "During mean annual flows (8.6 cfs through the study area), control points are vegetation choking points in the wetland downstream of 148th Ave " SE bridge and mildly so upstream of 148th and gravel deposition where Long Marsh enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5,04. Similarly for higher flows (e.g, 1 year event), Long Marsh again controls water surfaces upstream for the same reach length." Again on pp 54: "These results are also dependant on the relocation of where Long Marsh creek deposits gravels during storm events. This tributary has clearly been shown in the past to deposit enough gravels to effectively backwater May Creek upstream of its confluence. Additionally, shear stresses in May Creek are far below forces necessary to mobilize gravels that are being deposited by Long Marsh creek." Well, shear stresses generally are lower in backwater areas. We visited this site, and the form and location of the gravel bar strongly suggests that the bridge is causing the excess gravel deposition probably due to the back water effect Therefore the bridge is the primary cause of the deposition and backwater effect extending 2000 feet upstream (from H and H study). The gravel would disburse downstream rather than creating an oversized gravel bar if the bridge were sized properly or removed during overbank flows. Instead of evaluating this option, the documents focus on removing the gravel and "mitigating" by removing the existing vegetation buffer along Long Marsh Creek and forcing the Creek into an unnatural planform. The documents acknowledge that the 148'" Street Bridge causes a backwater effect This effect can be seen of the FEMA longitudinal flood profiles. While the effect is more local resizing the bridge would also increase hydraulic efficiency just upstream of the bridge. The Long Marsh Creek mitigation project is not mitigation. The proposed stream alignment does not appear to be based on the existing or historic channel characteristics. The LiDAR data shows an alluvial fan but it indicates that there were distributary channels rather than a single channel meandering stream (Figure 1). A similar situation occurs on the Indian Meadows alluvial fan. The proposed planform and the area allotted for channel movement is not natural to an alluvial fan • Page 2 system so is not a restoration project but more of a drainage efficiency project not related to historic fluvial processes and landforms. Geomorphic analysis The geomorphic interpretations and sediment transport study appear to be done by persons not well-versed in fluvial geomorphology and channel response. For example, the Sediment transport study conducted in the ravine (Anchor QEA, LLC, 06/2009) relies on pebble counts along 3 transects for evaluating sediment transport Pebble counts tend to be biased towards larger sediment This bias means that the median sediment size, for example, could be larger than it really is resulting in higher discharge estimate to mobilize bedload. This may explain why the calculated effective sediment mobilization"discharges are between the 5-10-year floods. In boulder areas this makes more sense. However, the sediment I saw in the near the Duffus and downstream properties is much smaller and should be mobilized at a lower discharge. The lower end" of the range (73-150 cfs) estimated in the Hand H study appears more realistic for the areas we observed. Moreover, for sediment transport pebble counts should be done primarily on bars not the channel. The sediment transport study appears to have only relied on cross-channel pebble counts. Plus, a statement is made that the channel maybe armored. Channels with pavement or armoringshould include a subsurface pebble count (e.g., Buffington and Montgomery 1997, 1999). As pointed out in the documents, HEC-RAS sediment transport model cannot address variable sediment transport conditions and changing channel elevations (erosion or deposition). Pebble counts may work for reconnaissance level study on the site basis (but not the whole reach), but not for a study related to assessing potential hazards such as damage to structures. Volumetric sediment sampling and more sample locations would be more appropriate in this case King County's Department of Natural Resources, Water and Land Resources Division have well qualified fluvial geomorphologists and geologists. The proponents of this project and the geomorphologists and geologists are in the same division. However, these qualified people appear to not have been consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomorphic processes that created the current conditions, and downstream channel response including migration to changes in flow and sediment regimes. The expertise is available within the same King County department and division. These people should be consulted on this project Downstream bank erosion. Since the sediment transport study and the Hand H study appear to rely on reconnaissance site level data that does not include adequate sampling points, I cannot make a determination " concerning potential for increased bank erosion downstream of the project area. There are many factors affecting bank erosion in the downstream reach such as riprap focusing flow against unprotected banks, reduction in natural sediment source from bank erosion, and head cutting from response to glacial lowering of the base level and more recent lowering of base level when Lake Washington water levels were lowered for transportation purposes. However, I disagree with the statement made in the Hand H study that the increase in frequency of smaller floods is insignificant While it may be the case, this hypotheSiS has not been tested using adequate data. This conclusion wouldn't be an issue if there were not structures downstream, but there are. The Hand H study indicates thatthe project will increase the frequency of occurrence for smaller floods (Table 8, pp 47-48). For example, the 1.01 year flood • Page 3 ---------------, (67 cfs) and 1.11 year flood (118 cfs) frequency of occurrence will increase by 16% and 10% respectively. The 2-year event, often considered a surrogate for effective discharge where data are not available, frequency will increase by 5%. The increase in frequency of these small floods could affect sediment transport dynamics. Simply put, the increase in small flood frequency will increase the occurrenc~ of unit stream power (specific weight ofwater*channel gradient * discharge/active channel Width) associated with these small floods by 16, 10 and 5%, unless gradient decreases or width increases. Since gradient is somewhat controlled by valley conditions, stream width is more likely to change. Stream power is an indicator of transport capacity. Increased transport capacity can lead to increased incision and bank erosion. Yet the Hand H study says there will be no significant effect There appears to be a disconnection in the conclusions supporting dredging. A 5-16% increase in stream power for potential sediment transport events is not Significant but a 0.04% decrease in flooding duration of 50 cfs is significant enough to dredge (Table 9, pp 53, Hand H study). Since there is disagreement between sediment transport numbers, King County should use its geologic and geomorphic expertise and further evaluate adding sampling points and designing an appropriate sediment transport and erosion study. Also the existing transport modeling should have independent review because not all sediment transport models apply everywhere. In the meantime King County and residents should explore other options such as increasing conveyance capacity under 148'" Street Bridge and footbridge just downstream of Long Marsh Creek. The foot bridge is obviously an imposition on water conveyance as the sediment wedge developed upstream testifies. The King County documents indicate that flood storage will be reduced in the project area, so additional flood storage to compensate for that loss should be included in the project The GLO survey notes describe upper May Creek from just downstream of the Renton-Issaquah Road and upstream as a crabapple swale. Vegetation consisted of Pacific crabapple, hardhack, willow and some indiscernible tea. There was no mention of any 'brook" or other flOwing water feature. The vegetation and lack of surface water implies it was a groundwater fed wetland. Restoration of some wetland functions in the project area as well as this area could increase flood storage and attenuate flood volumes downstream. Other options include, reducing reed canary grass, reducing or eliminating fine sediment sources (those above background), and replanting vegetation that was documented to occur in the area including cottonwood, ash, maple, cedar and undergrowth species such as alder, native Pacific crabapple (Malus fusca), and vine maple . • Page 4 c---------------- Page 5 References Buffington, j.M., and Montgomery, D.R 1997. A systematic analysis of eight decades of incipient motion studies, with special reference to gravel-bedded rivers. Water Resour. Res. 33: 1993-2029. Buffington, j.M., and Montgomery, D.R 1999. Effects of sediment supply on surface textures of gravel-bed rivers. Water Resour. Res. 35: 3523-3530 Galloway, Devin, David R jones, and S.E.lngebritse, eds. 1999, Land Subsidence in the United States U.S. Geological Survey Circular 1182. ,-------------------------- Page 6 Figure 1: A relative water surface elevation DEM was derived from the LiDAR bare earth DEM. The DEM shows t he relative height of land surface in relation to water surface (in feet) at the time of the LiDAR flight The blue values indicate areas that are below the water surface elevation. --[lslrtbutaryJrac:es --~pecMay-cr1I;_slream Up_may_rwae <VALUE> _ -7 .71--7.5 _ -7 .'0--7 ~.99 --6.5 __ -6.49--6 c:::;:J -539 --5.5 Cii] -5 .'9 --5 D .. 39-... 5 c:::J ".'9 --. 0-339--3.5 0-3··9--3 0-2.09--2.5 0-2 .• 0--2 0-139 --1.5 0-1 .• 9 --1 D.o·oo-.o.5 D.o·· .. -o 00.001-0.5 0 0.501 -1 01.01-1.5 01.51-2 02.01-2.6 02.51 -3 D3.01-~5 D~51-' 0··01-•. 5 0··51-5 05.01-5.5 05.51-6 06.01 -6.5 06.51-7 07.01-7.5 07.51 -8 ; D8.Q1-8.5 0 8.51 -9 00.01-0.5 00.51-10 010.1-10.5 010.6-11 011.1-11 .5 D 11.6-12 c:J 12 .1 -12.5 012.5-13 D 13.1-13.5 D 13.6-14 D 14.1-14.5 14 .6 -15 STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Norlhwest Regional Office' 3190 160lh Avenue Sf' Bel/evue, Washington 98008-5452 • (425) 649-7000 September 1, 2011 Doug Chin, Project Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 RE: U.S. Army Corps of Engineers (Corps) Reference #NWS-2010-1S8 Status of Application for Section 401 Water Quality Certification and Coastal Zone Management Consistency for the May Creek Drainage Improvement Project, Renton, King County, Washington Dear Mr. Chin: The U.S. Army Corps of Engineers (COlpS) issued a joint public notice with the Department of Ecology (Ecology) for the above project on September 24,2010. Ecology has one year to issue its individual Section 401 Water Quality Certification (WQC). On August 31, 2010, Ecology notified you by certified letter that this project would require an individual WQC and Coastal Zone Management Consistency (CZM) determination and requested additional information. Throughout the review of this project, Ecology has raised a number of questions about the purpose and need of the project, as well as technical issues regarding the wetlands, sediment lI1!flSport, and water quality (see Attachment 1). As the statutory deadline of September 23. 2011 aWroaches. we are concerned that many of these issues have yet to be fully addressed and we will not have reasonable assurance that water quality standards will be met. In order to complete the WQC process and make our CZM determination; we need the following additional information: • Description of how the sediment disposal areas will be stabilized in order to prevent fine material from entering waters of the state (including wetlands). • Construction Water Quality Protection and Monitoring Plan (King County, July 2011): o Page 1, Section 2: The citation for the section of the water quality standards that allows a temporary area of mixing for turbidity during construCtion should be cOrrected from wAc 173-201A-400 (4) and (6) should be corrected to WAC 173- 201A-200(I)(e)(i). Doug Chin, Project Manager September I, 2011 Page 2 of6 o Page 2, Section 3, Sampling Locations: Ecology agrees that the background and point of compliance sampling locations will need to change as the project moves from segment to segment. And it is understood that Figure 1 is a representative site plan showing sampling locations. Please note that background samples should be taken at the same time as the point of compliance samples. o Page 4, Section 3, Long-term Data Storage and Reporting: The plan iitdicates that data will be provided to regulatory agencies upon request. The plan should be. updated to reflect that ifno exceedances are detected results of water quality sampling should be sent to my attention at Ecology on a monthly basis and that any exceedances should be reported within 24 hours with the following information: a. A description of the nature and cause of exceedance. b. The period of non-compliance, including exact dates, duration, and times and/or the anticipated time when the Applicant will return to compliance .. c. The steps tsken, or to be taken, to reduce, eIiminate, and prevent recurrence of the non-compliance. d. In addition, within five (5) days after notification of an exceedance, submit a written report that describes the nature of the exceedance, turbidity results and location, photographs, and any other pertinent information. • It is expected that there will be stream water temperature changes between the time the County removes more mature vegetation and when the replanted vegetation reaches the size to shade the creek, creating an additional impact to water quality. What measures will be tsken to address this? • The May Creek Drainage Improvement Project (9AI205) King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan, prepared by King County Road Services Division, revised July 2011, needs to be revised to: o Vegetative coverage of 80 percent under Section 6.1, o Replanting of dead plants to J 00 percent for· years J and 2 under Section 6.1, and . o Include submittal of an As-Built Report and monitoring reports for years 1 and 2 under Section 6.2, Post-Construction Monitoring, • The memorandum from Julia Tumey to Doug Chin, King County, R.E: May Creek Drainage Improvement Project: SE May Valley Road 148 th Avenue S~Sedim~nt Assessment, dated February 9, 2011, does not address what sediment volumes will be transported and where fine sediment will be deposited downstream other than to say it will not be Lake Washington. While the memorandum states that the project will decrease the agricultural sediment source at some time in the future, it does not say how long the increased sediment load will occur. The memorandum states that quantitative sediment estimates are not available (page J 6). Doug Chin, Project Manager September 1, 2011 Page 3 of6 King County developed a plan to monitor for erosion downstream from the project area (memorandum from Don Althauser, King County, to Bill Kerschke and Julia Turney, King County, RE: May Creek Drainage Improvement Project (9AI20S) Post- Construction Erosion Monitoriog Plan -Downstream of 148th Avenue SE, dated August 4,2011). The plan needs to be revised to include the project area. The sediment monitoring plan should monitor sediment accumulation or erosion in the creek and changes in channel cross-sections and longitudinal profile to provide information on project effectiveness. It also should include contingencies in case the project does not perform as expeCted. • The revised JARP A #6a, StreamlWetiand Mitigation, first bullet, states that fencing will be installed around the planting areas to minimize livestock access to the stream. This appears to refer to the riparian planting buffer on both sides of May Creek-is this correct? Current site plans show fencing around the mitigation area west of 148 th Avenue SE, however the plans are do not show fencing that would permanently exclude livestock from direct access to the restored riparian planting buffer area and. creek upstream of 148th Avenue SE. The plans should be updated to reflect this. • #6d of the JARP Arerers to a riparian planting buffer along Long Marsh Creek. Will the buffer be on both sides of the creek? How wide will the buffer be? Will there be a buffer along the new side channel, and if so, how wide will this buffer be? Are the riparian buffer areas along Long Marsh Creek and the side channel included in the proposed mitigation calculations-Ecology does not believe that this should be included. • #6d of the JARPA mentions that 16 pieces oflarge woody debris will be placed in the off-channel alcoves. Does this figure mclude the snags? And is it correct that another 60 pieces cif large woody debris will be placed in the wetland enhancement area per the JARP A? These figures are Inconsistent with the May Creek Drainage Improvement Project (9A1205) King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan, prepared by King County Road Services Division, revised July 2011, page 4, first bullet, which states that 76 pieces oflarge woody debris and 2 snags will be installed. These figures need to be clarified. • In King County's July 22,2011 response to May 11, 2011 comments by Karen Walter, . Muckleshoot Indian Tribe (page 3), the County mentions a Draft Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report and says that the final repOlt will be available upon request. Please provide a copy of this report to Ecology. • On September 16,2010, Ecology noted concern about the IS-foot riparian vegetation buffer in comments on the State Environmental Policy Act Mitigated Determination of Non-Sigcificance (MDNS). Specifically, we questioned the effectiveness of this size buffer in shading out reed canary grass and stated that we could not support the proposed Doug Chin, Project Manager September 1,2011 Page 4 of6 project with this size buffer. The proposed IS-foot buffers remain below the best available science which would more closely approximate 30-35 feet. As Karen Walter of the MuckleshootIndian Tribe has pointed out (May 11, 2011 comment letter to Ecology), King County Code requires existing livestock operations to . implement a farm management plan or meet management standards outlined in the Code. In King County's July 22, 2011 response to Ms. Walter, you indicate that two of the fOill' livestock operations have developed plans and that the buffers specified in these plans are 25 feet-I 0 feet more than the County is proposing. • In Ecology's comments on the MDNS we also hoted that the proposed planting of the "buffer" particularly on the left bank in Reach 4 is problematic because this area is NOT . buffer. It is wetland that likely receives runoff from upslope seepage as well as bank ovel10pping. This area is very wet and needs to be planted with native vegetation that can tolerate long periods of inundation. Concerns remain with regards to plant establishment in wetter reaches, specifically on the left bank upstream of Long Marsh Creek. Site plans are not specific as to which plants will be installed in this reach. • It is Ecology's assessment that backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge, extending 2,000 feet upstream. The form and location of the gravel bar indicates. that the bridge is the primary cause for excess gravel deposition probably due to the backwater effect. Therefore, it appears that the bridge, rather than the gravel bar, is the primary cause of the deposition and backwater effect extending 2,000 feet upstream. The report focuses on dredging and vegetation removal, without considering resizing or removal of the bridge. Additionally,the documents acknowledge that the 148th Avenue SE Bridge causes a backwater effect. Resizing the 148 th Avenue SE bridge would increase hydraulic efficiency just upstream of the bridge. King County and residents should explore other options such as increasing conveyance capacity under the 148th Avenue SE bridge and the footbridge just downstream of Long Marsh Creek. • Ecology believes that the effectiveness of the proposed action for the stated intent of decreasing the duration of surface water on the grazed wetlands: o Has not been fully demonstrated to merit the level of impacts proposed for 0.04% decrease in flooding duration of 50 cubic feet per second (cfs), and o· One-time dredging will not solve the flooding extent and duration over time because large floodplain areas lie below the channel elevation; water inflow into the wetland system appears to be greater than the outflow; no upstream sediment study has been provided with detailed plans to reduce upstream sediment; changes to the l48th Ave SE bridge and footbridge downstream of Long Marsh Creek have not been proposed to increase conveyance capacity. • King County's Department of Natural Resources, Water and Land Resources Division has well qualified fluvial geomorphologists and geologists on staff; however, it does not r------------------------------------------------------- Doug Chin, Project Manager September I, 2011 Page 5 of6 appear that they were consulted for evaluating the sediment transport study, baseline geology and hiStoric channel form and geomolphic processes that created the current conditions, the downstream chanoel response including migration to changes in flow and sedinient regimes. The studies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data King County should utilize its geologic and geomorphic expertise and further evaluate adding sampling points and desigrIing an appropriate sediment transport and erosion study. Additionally, the existing transPOlt modeling should have independent review because not all sediment transport models apply everywhere. Ecology questions the premise upon which the proposal is based and cannot complete its review imtil this work is complete and the County has reassessed the project. Unless we receive all of the above documentation by September 16,2011, Ecology will have to deny the WQC/CZM for this project. Receipt of a denial without prejudice does not preclude you from resubmitting a request for 491 Certification at a later date. Please contact me if you have any questions regarding this letter or the 401lCZM Certification process at (425) 649-7129 or e-mail atRebekah.Padgett@ecy.wa.gov. Sincerely, (!{(!jtI Federal Permit Manager Shorelands and Environmental Assistance Program RRP:cja By certified mail #7011 0470 0003 3720 8964 Cc: TJ Stetz, U,S. Army Corps of Engineers Lori Lull, U.S. Army Corps of Engineers E-Cc: Patrick McGraner, Ecology Patricia Olson, Ecology Erik Stockdale, Ecology Loree Randall, Ecology Doug Chin, Project Manager September 1, 2011 Page 6 of6 3/24/10 5/5/10 9/16/10 4/26/11 4/28/11 Attachment 1: May Creek Key Ecology Correspondence Chronology Ecology raised concerns in an e-mail that followed up on a 2/22/10 site visit,· including the effectiveness, purpose, and need of the project, as well as the effectiveness of the 15-foot-wide buffers. Ecology p8.lticipated in an interagency pre-application meeting where. we provided substantive comments regarding the effectiveness, purpose, and need of the project, as well as the need to redelineate the wetland, buffer width, and livestock access to the creek. Ecology submitted comments on the State Environmental Policy Act mitigated determination of non-significance regarding effectiveness, purpose, and need of the proposal, buffer width, how wet the left bank is in Reach 4 for establishing canopy cover, the degradation of the pastures and need for farm plans to protect riparian habitat and creeks, and livestock access to the creek. Ecology participated in an interagency site visit where we raised questions about the effectiveness, purpose, and need of the project, permanent protection of the mitigation area, the buffers on Long Marsh Creek, whether the Long Marsh Creek work was really mitigation, monitoring of sediments in the project area and downstream, best managenient practices, buffer width, how wet the left bank is in Reach 4, the need for future dredging. Ecology followed up bye-mail documenting questions raised at the 4/26/11 site visit. -------------~ ~-- Gerald Wasser From: Sent: To: Cc: Subject: Julie P. Bonwel/ Ubonwel/@Iesourd.com] Friday, September 09, 2011 3:37 PM Gerald Wasser Hebe Bernardo LUA 11-065 May Creek Project Gerald C. Wasser, Associate Planner City of Renton Dear Mr. Wasser: EXHIBIT 16 PLEASE DO NOT ISSUE A PERMIT TO THE COUNTY ON THEIR PROPOSED PROJECT ON MAY CREEK. Our family home is immediately downstream of the proposed project. Access to our home is across a privately-owned bridge built many years ago. We have witnessed firsthand the damaging effects of runoff and erosion on our creek banks and bridge abutments and believe the project as currently proposed to be meritless. We feel vulnerable, even threatened, by the County's proposal to dredge and relocate a stream bed in an effort to "enhance" drainage of a wet land (horse pasture). We experience seasonal flooding on our property. We believe the project without consideration for the homeowners 'most impacted, from beginning right down to the type of trees it intends to replant. The County should be measuring bank stability and bank erosion of the specific areas at risk. Permits to the County at this juncture are premature at best. Julie & Jim Bonwell Katie Bonwell 2914 Lyons Avenue NE Renton, W A 98059 1 l Gerald Wasser From: Sent: To: Jennifer T. Henning Thursday, September 15, 20112:19 PM Gerald Wasser EXHIBIT 17 - Subject: FW: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 401 c and CZM Attachments: May Creek Dredging 401c and CZM Public Notice comments. pdf From: Karen Walter [KWalter@muckleshoot.nsn.us] Sent: Thursday, September 15, 2811 2:86 PM To: ECY RE FED PERMITS Cc: Lull, Lori C NWS; Randy McIntosh; 'Fisher, Larry D (DFW)'; Padgett, Rebekah (ECY); McGraner, Patrick (ECY); Dave Garland; Jennifer T. Henning; Chin, Doug; Hartley, James Subject: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 481c and CZM To Whom It May Concern, Attached you will find comments from the Muckleshoot Indian Tribe Fisheries Division in response to the Public Notice of Application for the above referenced project. A signed hard copy has also been sent to the Olympia office of Ecology. Please let me know if you have any questions. Thank you, Karen Walter Watersheds and Land Use Team Leader Muckleshoot Indian Tribe Fisheries Division 39815 172nd Ave SE Auburn, WA 98892 253-876-3116 1 · MUCKLESHOOT INDIAN TRmE Fisheries Division 39015 -172nd Avenue SE • Auburn, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 May 11,2011 Washington Department of Ecology-SEA Program Federal Project Coordinator P.O. Box 47600 Olympia, W A 98504 RE: May Creek Drainage Improvement Project 401c and CZM Consistency Public Notice of Application Dear Sir or Madame: The Muckleshoot Indian Tribe Fisheries Division (MITFD) has reviewed the Public Notice of Application for a State of Washington 401 Water Quality Certification and Coastal Zone Management Act Consistency for the May Creek Drainage Improvement Project. This project is the first of potentially four phases to dredge May Creek. In this first phase, the project proposes to dredge May Creek from Rivermile 4.3 to Rivermile 4.9, removing sediments, reed canarygrass and some of the existing willows that are within the flooded area of concern. As noted in previous comments, the MITFD has expressed concerns about proposals to dredge May Creek because of potential adverse impacts to salmon and their habitats. This project proposes to dredge 2,000 linear feet of May Creek and its associated wetland in areas identified as salmon spawning and rearing habitat (May Creek Baseline Stream Conditions Report). As noted in various May Creek documents reviewed, this is the first dredging proposal of potentially four projects that would result in the dredging of 2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. The combined impact of all of these dredging projects would likely result in a significant loss of existing salmon habitat, and potentially future adverse impacts upstream and downstream from the dredged reaches as other landowners seek to protect their properties from bank erosion. We recommend that King County implement and exhaust all less impacting alternatives prior to dredging May Creek. We remain concerned that this project will adversely affect salmon and aquatic habitats without sufficient mitigation for these impacts. The project proposes to directly impact the natural process of sedimentation and floodwater storage along May Creek without adequately assessing the potential impacts to salmon and their habitat in the project area and in upstream and downstream areas. In particular, the potential pre-and post-project rearing habitat available for juvenile salmon in May Creek has not been quantified .. Furthermore, for those impacts which have been quantified, the project impacts exceed the proposed mitigation in length and area. While the proposal to fence and plant native wetland! riparian vegetation I i I' Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401c and CZM Public Notice May 11, 2011 Page 2 . and create alcoves with wood and sediment is an improvement over the existing conditions for most of the project area, the extent of these mitigation measures is insufficient to mitigate for the potential loss of 48,000 square feet ofinstream habitat as a result of this dredging project. The planting buffer is significantly less than the regulated buffer and would provide inadequate riparian functions as a result. Additional mitigation for this project will likely be required to fully mitigate for the unavoidable environmental impacts from the project. Mitigation should include maximizing the natural processes that create and sustain salmon habitat including: I) improving pasture conditions and controlling other existing sediment sources through agricultural best management practices, farm conservation plans, and other measures as appropriate; 2) greatly minimizing the dredge area; 3) adding additional habitat mitigation to the dredged portion; 4) increasing the streamlwetland buffer width to the regulated 25 foot buffer width and increase riparian plantings; 5) avoid impacting downstream portions of May Creek; and 6) mitigating any unavoidable impacts to downstream areas. We are concerned that this project is a "short term fix" and that there is a high likelihood that additional dredging will be proposed elsewhere andlor in the future that may again adversely affect May Creek, its associated wetlands, and potentially the mitigation implemented for this project. Instead we recommend focusing more effort on the obvious land use and pasture-related sediment sources and allow the May Creek more room to store and. transport its sediment load, consistent with natural stream processes, Additional specific comments and questions about this project are attached for your review and consideration, Please let me know if you have any'questions at 253-876-3116. Sincerely, K~IN~ Karen Walter Watersheds and Land Use Team Leader Cc: Lori Lull, USACOE. Randy Mcintosh, NMFS Larry Fisher, WDFW Region 4 Rebekah Padgett, WDOE, NW Region Patrick McGranger, WDOE, NW Region Dave Garland, WDOE, NW Region Jennifer Henning, City of Renton Planning Doug Chin, King County DNRP Jamie Hartley, King County DDES Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and ClM Public Notice Other Potential Alternatives . May 11, 2011 Page 3 We are concerned that King County has not fully pursued all available alternatives that could reduce the need to dredge the entire area proposed under Phase I (and future phases) and reduce the amount of native vegetation removals to better protect existing instream and riparian functions. For example, most of the properties that would benefit from Phase I dredging are used for livestock pasture. King County Code (Title 21.A.30) regulates these areas to "support the raising and keeping of livestock in the county in a manner that minimizes the adverse impacts of livestock on the environment particularly with regard to their impacts on water quality and salmonid fisheries habitat in King County watersheds ". It is not clear how the adjacent properties are in compliance with this code which limits the maximum number of livestock on a per acre basis. As part of the Code compliance, property owners are required to have a farm plan with maximum densities of livestock. These farm plans require: "Site-specific management measures for minimizing nonpoint pol/ution from agricultural activities and for managing wetland and aquatic areas including, but not limited to: a. livestock watering; b. grazing and pasture management; c. confinement area management; d manure management; and e. exclusion of animals from aquatic areas and their buffers and wetlands and their buffers with the exception of grazed wet meadows. "(KCC 21A.30.045.2). It should be noted that KCC 21.A.30.045.B requires that farm management plans seek to achieve a "minimum 25 foot buffer of diverse, mature vegetation between grazing areas.and the ordinary high water mark of all type S and F aquatic areas and the wetland edge of any category I, II or III wetland with the exception of grazed wet meadows, using buffer averaging where necessary to accommodate existing structures." The proposed mitigation buffer for dredging is a maximum of 15 feet that is substantially less that the County Code. Another problem is that the mitigation buffer area is not proposed to be permanently protected in a conservation easement. From our field visit on April 26, 2011, it appears that the properties in question are not complying with King County Code Title 21.A.30. Prior to the approval of any dredging proposal that will adversely impact salmon habitat in May Creek, we recommend that the properties demonstrate compliance with Title 21.A.30 in that the property owners have minimized their contributions to the sedimentation and flooding problem, including providing a vegetated buffer to control sediment loading and shading out the existing reed canarygrass in and along May Creek and its tributaries. The project should also evaluate the potential for the existing SE 148 th Street Bridge to create an obstruction and create backwater conditions that cause sediment to deposit upstream. Per the Hydraulic and Hydrologic Analyses for the project (December 2010), this bridge cannot pass a 100-year flood without overtopping the roadway. I' I I I ,---------------- Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice Project benefits May 11, 2011 Page 4 The purpose of the project is to reduce the duration of flooding on local property owners by removing in- stream channel obstructions. There should be further analysis that discusses how much used pasture area will have reduced flooding and for what duration for each of the affected properties to determine project impacts versus potential benefits. The Hydraulic and Hydrologic Analysis report suggests that the decrease in flood durations at 100 cfs is 7 hours which suggests little benefit for substantial environmental impacts to May Creek. Project Impacts We are concerned that the existing rearing habitat in May Creek will be lost through the combination of channel dredging, reed canarygrass removal, and removal of in-water and adjacent willows. There is no estimate given for the potential loss of rearing habitat. However, the impact analysis indicates that the total impact area is 43,995 square feet (1.01 acres), whereas, the proposed mitigation area at the two off- channel alcoves is 10,238 square feet (0.24 acres). This is less than a 1: 1 ratio of impact to mitigation area and will likely result in unmitigated impacts to existing rearing habitat for juvenile salmon. In addition, details are lacking regarding the flood event needed to connect the alcoves to May Creek, the corresponding water depth in the alcoves, how long they will be inundated, and how much rearing habitat would be created. If the alcoves are not fully connected to May Creek or the entire area is not inundated, then the mitigation area alcoves may actual provide less habitat than the proposed 10,238 square feet and also may potentially result in stranding mortality. The project has not adequately described or analyzed the sediment sources coming into May Creek from Long Marsh Creek. For example, it is not clear if undersized culverts on Long Marsh Creek are contributing to bank erosion and contributing to the sediment load. Alternatively, upstream stormwater contribution may be causing sediment transport in Long Marsh Creek too. Additional information is needed to assess the contribution from Long Marsh Creek and if needed, measures taken since Long Marsh Creek was identified a major contribution in the County's sediment assessment report. Finally, we do not view the proposed Long Marsh Creek work as mitigation for reasons noted below. It is also unknown what benefit, if any, would occur from creating a side channel at the Long MarshlMay Creek confluence to trap sediment. It seems likely that this constructed feature would fill in from upstream sediment, since the mitigation design is not providing sufficient width in the upstream portions of Long Marsh Creek to slow down the rate of sediment transport and retain sediment in the channel upstream. In addition, the proposal to remove existing red alders that are 10-15 years old with smaller trees in the same 15 foot wide buffer on Long Marsh Creek is an impact, not mitigation. The project may not have fully considered potential impacts to Chinook, coho, and sockeye salmon, According to the Stream and Wetland Impact Analysis and Mitigation Plan, King County indicates that chinook and sockeye salmon do not travel upstream as far as May Valley. However, King County has data from the Salmon Watcher's program that indicates that adult Chinook, sockeye, and coho were reported as far upstream as Greene's Creek in 2001, which is just downstream of the SE 148tb bridge. (see http://your.kingcounty.gov/dnrp/librarv/archive- l 'I, Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and eZM Public Notice documents/wlr/waterres/salmon/Maps/200 11020 5di stroEASTlake W A. pdf). May 11. 2011 Page 5 The project also needs to mitigate for the loss of the full channel spanning pool at the Long Marsh Creek confluence. This pool will be eliminated by the stream dredging and not replaced based on the proposed mitigation plans. Since pools are limited in this portion of May Creek per the baseline stream conditions report, the pool should be replaced, potentially downstream of SE 148 th adjacent to the NGPE tract for Stonegate where there are fewer constraints. Alluvial fans are natural features at Long Marsh Creek and farther upstream at Indian Meadow Creek. According to the sediment assessment report, these features have been documented ill the May Creek Valley since 1872. As a result, they will likely be continued sources of sediment to May Creek. Phase I and the future phases need to develop strategies that accommodate these natural features instead of proposing dredging now and into the future. The project may also aggravate existing conditions for water temperature and dissolved oxygen in May Creek. Currently May Creek through the May Valley is shown as a "Category 2" water for temperature and dissolved oxygen on Ecology's 2008 303 (d) list. The removal of vegetation along 0.6 miles of May Creek that currently provides shade may worsen this condition. Once a redesigned project has been developed that addresses the concerns above, then a water quality protection plan and a monitoring plan that assesses the project's effects on sediment transport/filling, flooding, habitat creation and riparian planting success can be developed. Any approved project should be monitored for 10 years to determine project success (or failure) prior to allow any new dredging. I I CITY OF NEWCASTLE TOWNSHIP PROJECT LOCATION (f) Z g -_L..:" EXHIBIT 18 S[ MAY VAllC"V '-r RD CITY OF RENTON STONEGATE 8035+0 UNDIVIDED INTEREST TRACT "An CITY OF RENTON w (f) w ~ THE EXISTING PHYSICAL FEAlURES SHOWN ON THIS PLAN ARE FROM G.I.S. PROJECT TITLE: ;.-;1 ~2,;,;:O--O~~~~~;-:-=:~~==--....:2:::.oo~1 MAY CREEK DRAINAGE IMPROVEMENT SCALE IN FEET IDIREClnONIS TO SITE: SHEET TITLE: tQ, FROM COAL CREEK PARKWAY (EAST OF VICINITY MAP 1-405) lURN EAST ON S.E. MAY VALLEY SCALE: H: 1" = 200' ROAD. GO TO 148TH AVE S.E., lURN SOUTH ASSISTANCE BY: LINDSEY MILLER King County MAY CREEK. DRAWN BY: MEREDITH RADELLA • I EXHIBIT 19 ! ~ I , I /I I·- "~ -I . "-:1} ,~i ~ill / ~I 7 i, / / ~ / • i / / • / ----Z.. ----- RECEIVED MAR 152m! KC. Roads Engineering Services NMFS Tracking Number: 2011/00601 Erick Thompson Road Services Division Department of Transportation KSC-TR-0231 201 S. Jackson Street /i--4 " . " • • \ ,; ~!UD'f' Seattie, Washington 98104-3856 EXHIBIT 20 UNITED STATES DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration NATIONAL MARINE FISHERIES SERVICE Northwest Region 7600 Sand Point Way N.E., Bldg. 1 Seattle, Washington 98115 March 10, 2011 Re: Endangered Species Act Section 7 lnfonnal Consultation and Magnuson-Stevens Fishery Conservation and Management Act Essential Fish Habitat Consultation for King County for the May Creek Drainage Improvement Project (Sixth-field Hydrologic Unit Code 171100120400, Lake Washington-Sammamish River). Dear Mr. Thompson: This correspondence is in response to your request for informal consultation under the Endangered Species Act (ESA) of 1973, as amended, 16 U.S.c. 1531. The National Marine Fisheries Service (NMFS) has reviewed the Biological Assessment (BA) for the above referenced proposal, received on February 25, 2011. King County (County) requested concurrence with its determination that the proposed action "may affect, but is not likely to adversely affect" the threatened Puget Sound (PS) Chinook salmon (Oncorhynchus tshawytscha) (70 FR 37160), and the threatened PS Steelhead (D. mylciss) (72 FR 26722). This consultation with the County is conducted under section 7(a)(2) of the ESA, and its implementing regulations, 50 CFR Part 402. There is no critical habitat in the action area. The County is proposing to improve in-stream flow conditions between approximately river mile (RM) 4.3 and 4.9 of May Creek. Sediment accumulation and in-stream vegetation have been gradually decreasing channel flow capacity, causing a backwater effect and increasing flood duration on pastures. The project includes vegetation and sediment removal, along with stream and wetland mitigation. Invasive reed canary grass and sediment will be removed from the channel with machinery, most likely a trackhoe operated from the bank. The stream will be diverted around the work site, and erosion and sediment control best management practices will be implemented. In addition, willows that are obstructing flow , would be removed by hand or with hand-held machinery. Approximately 4,050 cubic yards of material will be removed from the stream channel. 2 As mitigation for these. actions, the County will enhance about two acres of wetland and riparian habitat by suppressing invasive vegetation and replanting with native vegetation. Fencing will be installed around the planting areas to minimize livestock access to the stream. In-stream mitigation activities will also Occur at two locations. At the first site on May Creek, the County will excavate off-channel alcoves, and enhance them with large woody debris and native vegetation. At the second site, the County will create meanders and plant native vegetation along 300 feet of Long Marsh Creek at the confluence with May Creek. A 100-foot long side channel will also be created at this site. These mitigation activities will increase habitat complexity and overwintering habitat, and increase sediment retention capabilities, reducing sediment transport to do~trearn reaches. The in-water work window will be August 1 through 31. In-water work will be limited to activities required to bypass the creek, including fish exclusion and installation of cofferdams. The action area will extend for 300 feet do~tream of the do~-most in-water work (i.e. to RM 4.2) to account for increased suspended sediment concentrations. In general, this type of project could affect ESA listed salmonids by increasing the amount of suspended sediments in the stream, by injuring fish with equipment, or by displacing fish from the project site. In addition, removal of vegetation from the riparian zone and stream channel could potentially affect shade, cover, and allochthonous input. Species Determination Neither PS Chinook salmon or PS steelhead have been documented witliin about 0.75 miles of the project action area. Thus, potential direct effects, including injury and displacement from equipment and in-stream work, will be discountable. The County will divert flows around the work site, helping to decrease the amount of suspended sediments drifting downstream. Also, suspended sediment concentrations will dissipate before reaching PS Chinook salmon or steelhead habitat, so potential effects will be insignificant. Potential reductions in shade, cover, and allochthonous input will have insiguificant effects due to distance of the action area from PS Chinook salmon and steelhead habitat. The NMFS concurs with the County's determination that the project "may affect, but is not likely to adversely affect" PS Chinook salmon and PS steelhead: This concludes informal consultation on these actions in accordance with SO CFR 402.14{b)(I). The County must reiuitiate the ESA consultation if: (1) new information reveals effects of the actions that may affect listed species in a way not previously considered; (2) the actions are modified in a manner that causes an effect on the listed species that was not previously considered; or (3) a new species is listed, or critical habitat is designated, that may be affected by the proposed actions. • ... , .' 3 Magnuson-Stevens Fishery Conservation and Management Act Federal agencies are required, under section 305(b)(2) of the MSA and its implementing regulations (50 CPR 600 Subpart K), to consult with NOAA Fisheries regarding actions that are autho~d, funded, or undertaken by that agency that may adversely affect Essential Fish Habitat (EFH). The MSA section 3 defines EFH as "those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity". If an action' would adversely affect EFH, NMFS is required to provide the Federal action agency with EFH conservation recommendations (MSA section 305(b)(4)(A». This consultation is based, in part, on information provided by the Federal action agency and descriptions ofEFH for Pacific salmon contained in Appendix A to Amendment 14 to the Pacific Coast Salmon Plan (August 1999) developed by the Pacific Fishery Management Council and approved by the Secretary ofColllIrierce (September 27, 2000). The proposed action and acticin area are described in this letter and in the BA. TIle action area includes habitat that has been designated as EFH for various life stages of Chinook and coho(O.~ch)~oa . EFH Conservation Recommendations: Because the conservation measures that the County included as part of the proposed action to address ESA concerns are also adequate to avoid, minimize, or otherwise offset potential adverse impacts to the EFH of the species listed . above, conservation recommendations pursuant to MSA (section 305(b)(4)(A» are not necessary. Since NMFS is not providing conservation recommendations at this time, no 30- day response from the County is required (MSA section 305(b)(4)(B». This concludes consultation under the MSA. If the proposed action is modified in a manner that may adversely affect EFH, or if new information becomes available'that affects the basis for NMFS' EFH conservation recommendations, the County will need to reinitiate EFH consultation with NMFS in accordance with implementing regulations for EFH at 50 CFR 600.920(k). The NMFS appreciates your efforts to comply with requirements under the ESA and MSA. If you have questions, please contact Jody Walters at the Washington State Habitat Office, (360) 534-9307, or email Jody.Walters@noaa.gov. Sincerely, c~ .Q. :::> cc: Lori ,Lull, COE .r; William W lie, Jr. "\) Regional A ministrator ---------- STATE OF WASHINGTON DEPARTMENT OF ECOLOGY EXHIBIT 21 Northwest Regional Office 3190 /60,h SE Belle,,"e, Washington 98008-5452 (425) 649-7000 September 22,2011 Doug Chin, Project Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 6.0.0 Seattle, WA 98104-3855 RE: Ecology Denial for Section 401 Water Quality Certification for the May Creek Drainage Improvement Project, Renton, King County, Washington Dear Mr. Chin: The U.S. Army Corps of Engineers (Corps) issued ajoint public notice with the Washington State Depm1ment of Ecology (Ecology) for the above project on September 24, 2010. Ecology has one year to issue an individual Section 401 Water Quality Certification (401 Certification). On August 31, 2010, Ecology notified you by celtified letter that this project would require a 401 Cel1ification. On April 21, 2.011 and September 1,2011, Ecology issued additional public notices regarding King County's two revised applications for 401 Certification. We determined that your application for an individual 401 Certification was incomplete and sent you a certified letter on September I, 2.0 II detailing the specific information that was needed to complete your application and stating that if Ecology did not receive all of the required documentation by September 16,2011, Ecology would deny the 401 Celtification for this project. In our September I, 20 II letter we identified the following information needed in order to complete our revicw: o A description of how sediment disposal areas will be stabilized. o A Construction Water Quality Protection and Monitoring Plan. o Measures to be taken regarding stream water temperature changes between removal of mature vegetation and when replanted vegetation reaches the size to shade the creek. o Revisions to the Mitigation Plan. o Revisions to the sediment monitoring plan. o Site plan revisions. . o Details on the Long Marsh Creek riparian planting buffer. o A copy of the Final Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report. o Expanded riparian vegetation buffers. o Study of the resizing or removal ofthe 148 th Avenue SE Bridge. King County Water and Land Resources Division' September 22, 2011 Page 2 • Reassessment and redesign of the project to address its effectiveness, including further evaluation and study of sediment transport and downstream erosion, as well as independent review of sediment transport modeling. On September 16, 2011, Ecology received a response addressing some of the infOimation requested. Unfortunately we have not received all of the documentation needcd in order to demonstrate that we have reasonable assurance that state water quality standards will be met. We have attached a project chronology that details that we have been trying to work with you to get the needed information in order to process your request for a 401 Certification. Pursuant to Section 401 of the Clean Water Act, ch. 90.48 RCW and ch, 173-201A WAC, !lie May Creek Drainage Improvement Project water quality certification is denied without prejudice. Receipt of a denial without prejudice does not preclude King County Water and Land Resources Division from resubmitting a request for 401 Certification at a later date. You have a right to appeal this Order to the Pollution Control Hearing Board (PCHB) within 30 days of the date ofreceipt of this Order. The appeal process is governed by Chapter 43.21B RCW and Chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.001(2). To appeal you must do the following within 30 days of the date of receipt of this Order: • File your appeal and a copy of this Order with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. • Serve a copy of your appeal and this Order on Ecology in paper form -by mail 01' in person. (See addresses below.) E-mail is not accepted. You must also comply with other applicable requirements in Chapter 43.21B RCW and Chapter 371-08 WAC. !Ap!{E{EgS·f\1'iJ1l1t!()e~ml.f:rN.rjNTf0'R~it~'liI~.,I\I~~~~i,~~~~~~~'¥lil~;a;J Departmenl of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, W A 98503 Pollution C,onlro) Hearings Board 1111 Israel Rd SW STE 301 Tumwater, WA 9850) Department of Ecology Attn: Appeals Processing Desk PO Box 47608 Olympia, WA 98504-7608 Pollution Conlrol Hearings Board -PO Box 40903 Olympia, W A 98504-0903 King County Water and Land Resources Division September 22, 2011 Page 3 . Please direct all questions about this Order to: Rebekah Padgett Depal1ment of Ecology NOlihwest Regional Office 3190 160tl • Avenue SE Bellevue, W A 98008 (425) 649-7129 Rebekah.Padgett@ecy.wa.gov Pollution Control Hearings Board Website www.eho.wa.gov/Boards PCHB.aspx Chapter 43.21B RCW -Environmental Hearings Offiee -Pollution Control Hearings Board http://apps.leg.wa.govIRCW/default.aspx?cite=43.21B Chapter 371-08 WAC -Practice and Procedure http://apps.leg.wa.govIWAC/default.aspx?cite=371-08 Chapter 90.48 RCW -Water Pollution Control http://apps.leg.wa.govIRCW/default.aspx?cite=90.48 Chapter 173-201A WAC -Water Quality Standards for Surface Waters of the State of Washington www.ecy.wa.govlbiblio/wacI7320IA.html Erik Stockdale, Unit Supervisor Wetlandsl401 Unit Shore1ands and Environmental Assistance Program Northwest Regional Office ES:rrp:cja Enclosure By certified mail 7011 0470 0003 3720 9107 September 22, 2011 King County Water and Land Resources Division September 22, 2011 Pagc4 cc: Lori Lull, U.S. Army Corps of Engineers TJ Stetz, U.S. Army Corps of Engineers Larry Fisher, Washington Department ofFish and Wildlife Karen Walter, Muckleshoot Indian Tribe Katie Bonwell e-cc: Patrick McGraner-NWRO Patricia Olson -HQ Loree' Randall-HQ Raman Iyer -NWRO ecyrefedpClmits@ecy.wa.gov Jennifer Henning, City of Renton Jhenning@Rentonwa.gov Jean Rollins urbanseparator@hotmail.com Debra Rogers herogers@comcast.net Susan Malin susiemalin@msn.com Gw')' Amundson garv.a@comcast.net Andrew Duffus klassicars@hotOlail.com Carol Tabacek caroltabacek@aol.com Mary Weirich marvvweirich@comcast.net A. Duffus blueheron6987@hotmail.com Julie & Jim Bonwell ibonwell@lesourd.com 1/26/10 2/22110 3124/10 5/5/10 5/13/10 6/24/10 Attachment 1: May Creek WQC Permitting Chronology Ecology attended an interagency meeting organized by King County with discussion about the potential to create a mUlti-agency permitting team. A brief introduction and overview of the project concept at this early stage was presented. The U.S. Army Corps of Engincers (Corps), Ecology, Washington Deprutment of Fish and Wildlife (WDFW), Muckleshoot Indian Tribe, Governor's Office of Regulatory Assistance, and King County representatives were present. Ecology attended a field meeting with King County, WDFW, and the Muckleshoot Indian Tribe. Ecology staff raised concerns about the effectiveness, purpose and need ofthe proposed project. Specific comments included: the effectiveness of the 15-foot-wide buffers, concerns about direct animal access to stream, severely degraded pastures and the need for fann plans, extent of the wetland and primary sources of hydrology, and concerns about establishing woody vegetation in very wet soils. Ecology observed that livestock have direct access on one of the project properties upstream of the project area. Ecology provided written comments via e-mail that followed up on the 2/22/1 0 site visit. Ecology participated in an interagency pre-application meeting and provided substantive comments regarding the effectiveness, pwpose, and need of the project, as well as the need to redelineate the wetland, buffer width, and limit livestock access to the creek. Ecology raised concerns about 303(d) listing for fecal colifonn and the preference for 35-foot buffers and wider planting on the south side buffer to reduce summer temperatures through shading. Ecology questioned the 2002 pilot desclibed by King County whcrc two sediment plugs were removed from side channels on the McFarland property, specifically whether it would bc comparable to the current proposal and what post- construction monitoring was completed. Ecology raised the question of whether the proposed one-time dredging would accomplish the goals of the proposal; the County indicated that it was planning a series of projects, working from this site upstream. Ecology also pointed out that the baseline stream report included language that contradicted and would not support this proposal. Downstream erosion concerns were discussed, and King County staff noted that they had conducted modeling and did not believe that the sediment removal would increase erosion downstream. King County submitted the Joint Aquatic Resources Pennit Application (JARP A) package to Ecology. The Corps can,celed the application. Ecology canceled the 40 I application based on the Corps' 5/13/10 action. ~---I r--~--------------- King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment 1 September 22, 2011 Page 2 8116/10 9/8/10 9116110 9/20/10 9122/10 9124/10 10110 10/23/10 12/16110 313111 3118111 King County submitted a revised JARPA to Ecology. King County submitted a Certification of Consistency with the Washington State Coastal Zone Management (CZM) Program to Ecology. Ecology submitted comments on the State Environmental Policy Act mitigated determination of non-significance (MDNS) regarding effectiveness, purpose, and need of the proposal, buffer width, how wet the left bank is in Reach 4 for establishing canopy cover, the degradation ofthe pastures and need for fatm plans to protect riparian habitat and creeks, and livestock access to the creek. Ecology received substantive public comments from downsU'eam residents. Issues raised included concerns about increased erosion, sediment transpolt tln'esholds, cumulative impacts, and the need for additional detailed study of the potential downstream impacts. Ecology received substantive public comments from the Muckleshoot Indian Tribe raising concerns about net loss of habitat, downstream erosion, insufficient buffers and the probability that the proposed dredging will be a short-term fix. Corps issued a joint public notice with Ecology. Ecology received substantive public comments from downstream residents. Issues raised included concerns about the purpose and need of the project, draining of wetlands, water quality, salmon habitat, increased flow, and bank erosion, as well as questions about the 2002 pilot. Ecology received substantive public comments from the City of Renton that included concern about effects of increased velocity, flow, or erosion on downstream propelties. Ecology received King County's responses to Ecology MDNS comments. In the response letter, the County defends the proposed I 5-foot buffer not as best available science (BAS) but as an improvement over existing conditions citing property owners' reluctancc to expand planting areas, states that it cannot require frum plans from private property ow.p.er~,or require owners with farm plans to implement them properly, and notes that the planting areas will be fenced and will therefore effectively eliminate livestock access to the creek. Ecology and King County jointly extended the CZM review period until 9/8/11. King County submitted another revised JARP A to Ecology. This revision included new impacts to Long Marsh Creek that the County refen-ed to as miti~ation, therefore reducing proposed mitigation downstrerun of 148' Avenue SE. King County Water and Land Resources Division May Creek Dminage Improvement Project Attachment 1 September 22, 2011 Page 3 4/5/11 4/21111 4/26/11 4/28/11 Sill 5111111 Ecology received substantive public comments from the Neighbors for May Valley, who raised concerns about stream flow velocity, volume and timing of stonn events, flooding and erosion. Downstream property owners requested that King County allow the project to be delayed at least one water year to establish a pre-project erosion baseline. The downstream citizens requested additional assurances that the proposed dredging will not have unintended negative consequences to downstream properties. Ecology issued a public notice on the revised application. Ecology participated in an interagency site visit where staff raised questions about the effectiveness, purpose, and need ofthe project, pennanent protection of the mitigation area, the buffers on Long Marsh Creek, whether the Long Marsh Creek work was really mitigation, project-specific monitoring of sediments in the project area and downstrcam, best management practices, proposed buffer widths, how wet the left bank is in Reach 4, and the need for future dredging. Ecology followed up bye-mail documenting questions raised at the 4/26/11 site visit. Ecology received substantive public comments from downstream property owners questioning assumptions being made by King County based on modeling within the Hydraulics and Hydrologic Analyses using limited data, expressing concerns about downstream erosion, increased turbidity, and the proposed 15-foot planting buffer as not meeting BAS or County code. Specific questions also were raised with regards to the adequacy of the information provided by King County that claimed that the 2002 pilot project along a 300-foot section of the creek upstream of the proposed project was successful, erosion thresholds, potential for shallow well contamination, flow velocity, volume and peak flow during stonn events potentially risking sole-access bridges to properties, and the adequacy of the 15- foot planting buffer. Ecology received additional substantive comments from the Muekleshoot Indian Tribe emphasizing the need to improve pastw'e conditions and control other existing sediment sources through agricultural best management practices andlor farm plans, minimize the dredging area with increased mitigation for impacts, increase the proposed planted buffer width, provide additional riparian plantings, measures to avoid impacts to downstream reaches, mitigation for any unavoidable impact to downstream reaches, future dredging projects, and potential impacts to . salrnonids. . ------------------------------- King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment I September 22, 2011 Page 4 6110/11 7/1/11 7/8/11 7/19/11 7/22111 Ecology received King County's responses to Ecology's 4/26/11 and 4/28/11 comments. In its letter, King County stated that downstream impacts have been sufficiently analyzed and that a formal monitoring plan is not wa11'anted; based on previous analysis and CUl1'ent design features, re-sedimentation monitoring is not wal1'anted at this time; and there are no future plans to implcment additional upstream sediment removal projccts. King County continued to defend the proposed IS-foot buffer as being adequate even within the very wet portion of the left bank in Reach 4. In response to ongoing concerns from Ecology regarding the effectiveness of the proposed project, King County again stated that the project is only designed to reduce overbank pasture flooding for a short period of time on each end of the rainy season and that monitoring wells have been installed to assess groundwater pre-and post-project. Ecology received King County's responses to a public comment in which the County restated that the 15-foot proposed planting buffer, while not based on BAS, is an improvement over existing conditions as demonstrated by the results of the 2002 pilot project upstream of the CUlTent proposal and that the continuous hydrologic watershed mode used accounted for all peaks, all durations and all . flow rates at all locations. King County reversed its position from 6/10111 and . agreed to conduct downstream monitoring for a period of 5 years post-project. Ecology responded to King County by requesting a copy of the downstream monitoring plan with note that the plan should be comprehensive and not simply address the issues raised by one property owner. Ecology received King County's responses to a public comment in which the County stated that downstream monitoring will be conducted for a period of 5 years and that if monitoring data collected clearly shows that erosion problems result from the project, that it will offer technical assistance and perform remediation. The County indicated that it has no future plans to implement additional sediment removal projects upstream of this project site. Ecology received King County's responses to a public comment stating that the project will not increase existing erosion problems downstream, proposing 5 years of downstream monitoring and working with the property owner on a solution if the monitoring shows downstream erosion resulting from this project. Ecology received King County's responses to the Muckleshoot Indian Tribe 5111/11 comments. The e-mail states that the COlmty does not have plans to implement the other three upstream dredging projects. In response to the tribe's comment that King County Code requires existing livestock operations to implement a farm management plan or meet management standards outlined in the Code, the County indicates that two of the four livestock operations have developed plans and that the buffers specified in these plans are 25 feet (10 feet more than the County is proposing through this project). The County also acknowledges that the 148th Avenue SE Bridge causes a backwater effect. \. King County Water and Land Resource~ Division May Creek Drainage Improvement Project Attachment I September 22, 20 II Page 5" 7/26/11 8/2/11 9/1111 9/7/11 9/14111 9/15/11 9/16/11 Ecology again visited the project site, including downstream properties. King County submitted another revised JARP A. The revision addresses Long Marsh Creek impacts and includes additional mitigation. Ecology sent a letter by Certified Mail to Doug Chin requesting additional infOlmation and stating that projcct 401 Ce11ification would be denied if the requested documentation was not received at Ecology by September 16,2011. Ecology issued a public notice on the revised application . . Ecology and King County jointly cxtended the CZM review period until 11/8/11. Ecology received a public comment from a property owner reiterating questions about the need for the project and concerns about downstream erosion and flooding impacts Ecology received public comments from a propel1y owner reiterating concerns about downstream erosion and flooding impacts, raising the need for additional erosion monitoring and stream flow devices, and questioning the need for the project. The property owner raises questions about the stream and wetland buffer width, storm surge flows, hydraulic and hydrologic analysis, cumulative impacts, compensatory stormwater storage, and the need for additional daui and analysis. Ecology received public comments from the Muckleshoot Indian Tribe rciterating concerns about salmonids and habitat, cumulative impacts, likely future dredging, insufficient buffer widths, and the adequacy of mitigation. The letter also notes the need to consider less-impacting alternatives, have enforceable farm plans in place, for further analysis on backwater effect of the McFarland/Gambini footbridge, to consider impacts of sediment deposition in the mitigation alcoves, for sediment accumulation and erosion monitoring, to collect data regaiuing changes in channel cross-sections and longitudinal profiles and data on flood frequency durations, to monitor for salmonid use, and for a contingency plan. Ecology received additional public comments reiterating concerns about downstream flooding and erosion. Ecology received King County's responses to the 9/1111 letter requesting additional information. While some questions were addressed, outstanding issues remain including: buffers, baseline data, and sediment transport and data about what will happen downstream. . A.Duffus 143rd Avenue SE Renton, WA 98059-3764 October 3, 2011 Phil Olbrecht Renton Hearing Examiner City of Renton 1055 South Grady way Renton, WA 98057 Re: LUAII-065. V-H. SP May Creek Dredging Pro;ect Dear. Mr. Olbrecht: , . EXHIBIT 22 This Master Application is part of a larger proposal to dredge May Creek. The project is an ill-conceived attempt to temporally reduce seasonal flooding in a grazed wetland, i.e. horse pastures! To accomplish this over 2000 lineal feet of May Creek will be dredged. Once dredged, the King County Water & Land Resources Division expects that storm-water will flow more freely downstream. Downstream properties already experience flooding and erosion that threatens our homes, rips away our property and imperils our sole-access- private-bridges. Repeat, our only access private bridges. (These bridges are our only way out because of development patterns and lack of easements. Repairing or replacing is prohibitive due to environmental regulations and the financial burden.) Downstreiun property owners and state, federal, and tribal agencies are strongly opposed to this dredging proposal because of the probable significant adverse impacts. The Preliminary Report to the Hearing Examiner is flawed. The report contains substantial errors in fact. There are gaps in relevant information. For example, no reference is made to scientific information available from the Washington State Department of Ecology. The staff recommendation is misguided and is clearly erroneous in light of the documentation. On September 22nd, 2011, the Washington State Dept. of Ecology formally denied King County the right to dredge May Creek. Ecology requires additional baseline information, design changes, assurances that there will be no downstream impacts and further mitigation. (Copy attached.) On August 15 th , 2011, the Department of Ecology released an internal memo from, Dr. Patricia Olson, Ecology's Senior Hydrogeologist. (See August 15, 2011 memo, attached) Dr. Olson, who reviewed all the documentation from King County and personally visited the site, questioned the lack of detail in the county's studies and design, the very effectiveness of the project, uncertainty as to downstream impacts, cost-benefits, etc. I repeat, this memo is from Dr. Patricia L. Olson, Master of Science, 'phD, and licensed hydro-geologist. She is the Senior Hydrogeologist for the State of Washington Department of Ecology. Dr. Olson publishes scientific documents on rivers, lakes and groundwater issues. Dr Olson lectures. Dr. Olson testifies as an expert witness. Dr. Olson's work is actually referenced in King County's documentation for this dredging proposal. The City received a copy of Dr. Olson's memo on September 14th, 2011. Why was this vital document not referenced in the staff report to the Hearing Examiner? I urge the Hearing Examiner to please read Dr. Olson's profession evaluation and give it the substantive weight it deserves in your deliberation. I have personally worked with City of Renton staff and council for almost thirty years. I know the City has good, well-meaning people. Together, we have made our community a better place to live. However, who on the Renton staff reviewed this Master Application? How much time was spent on review and research? What is the staffreviewers' level of expertise? How could they make a recommendation to proceed given Dr. Olson's thorough design review, recent site visit and subsequent damming oUhe proposal? Did city staff visit the site? Did city personnel physically look at the downstream erosion and flooding conditions and the at-risk sole-access-private-bridges? I am hesitant to say the staff's recommendation is arbitrary and capricious, but I am tempted. On September 1st, 2011, the State Department of Ecology informed Water & Land Resources Division that, "Unless we receive all of the above documentation by September 16th , 2011, Ecology will have to deny the WQC/CZM for this project." (Copy attached) The city also received a copy of this letter on September 14th, yet it is not mentioned in the preliminary report. On September 22od, 2011, Ecology formally denied the Section 401 Water Quality Certification for the May Creek Drainage Improvement Project. While the denial notification acknowledged Ecology "received some of the information requested ... we (Ecology) have not received all of the documentation needed in order to demonstrate that we have reasonable assurance that the state water quality standards will be met." Why is the state Dept. of Ecology denial not given substantial weight? It is a pretty big deal that the state refused to certify the county's proposal! Yet, there is no reference to the state decision to deny certification except in one sentence in the preliminary report. Almost a fOotnote! . MAJOR POINT ! A COPY OF ECOLOGY'S DENIAL WAS NOT EVEN INCLUDED AS ANEXIlIBIT in the preliminary report. How can an omission like this occur??? City staff has not only over looked the facts; there is a gap in relevant information. If the state Department of Ecology in its wisdom, expertise, and experience denies King County the right to dredge, how can the City of Renton even consider approving the Critical Areas Variance and issuing the Special Grade & Fill Permit? Especially; given that the denial is determined, in part, on the probable significant adverse impacts to the critical areas. The Department of Ecology has repeatedly "provided substantive comments (questioning) the effectiveness, purpose, and need of the project." Dr. Olson in her words asks why King County did not consult with the county's very own qualified fluvial geomorphologists and geologists on staff. (See her actual quote in footnote 1. below.) Just two weeks ago, the Muckleshoot Indian Tribe repeated their recommendation, " ... that King County implement and exhaust all less impacting alternatives prior to dredging May Creek ... " (Letter to Washington Department of Ecology-SEA Program dated September 15th , 2011, copy attached) Apparently, this letter is not included in the preliminary report either. These documents must be accorded substantive weight in the City's decision on this Master Application to Fill & Grade and seek a Critical Areas Variance. The Washington State Dept. of Ecology has denied King County the right to dredge May Creek. Ecology is requesting more baseline information, design changes, assurances that there will be no downstream impacts and further mitigation. Obviously, the project will need to be significantly re-engineered to comply with state and federal requirements. Conceivably additional mitigation may be required in the big wetland. Perhaps additional off -channel alcoves or secondary by-pass channels. Possibly additional stormwater storage to compensate for up-stream dredging and reduction of natural storm water retention. To meet permitting agencies' requests the final design in the Tract A wetland will be quite different from the county's current proposal. The City of Renton cannot assess the probable significant impacts with the information currently available. The state and the Muckleshoot Indian Tribe are asking for larger planting buffers and perhaps more or larger off stream alcoves, all which will increase the impact of the clearing and grading. The City needs to appraise the final design changes before approving the Critical Areas Variance and issuing the Special Grade & Fill Permit. Questions: What will be the impacts of the revised design, both to the wetland and downstream? Will these design changes further disturb this natural wetland, if so to what degree? What further mitigation will be required? The proposed project is in a relatively undisturbed wetland on the rural growth line and is an important part of the wildlife corridor from Cougar Mountain to May Creek Canyon. The project will significantly adversely impact the riparian zone, i.e. fish and wildlife habitat. Three acres of this 3.75-acre wetland (80%) will be impacted by this project. If there are not permanent adverse impacts, there will most certainly be temporary impacts as the creek is dredged and wetland altered. The riparian zone will be cordoned offwith orange silt fences. The morning air will be filled with a cacophony of growling diesel engines and piercing backup alarms as heavy construction equipment churns through the wetland. Not to mention the diesel fumes. The county is proposing three-strand barbwire fences. Hardly user friendly for wildlife! The city's own regulations call for no fences in opens spaces unless absolutely necessary. In the past, when necessary, the city specified split rail cedar. See LUA-05-083 Preliminary Report to the Hearing Examiner, November 29th, 2005. That plat was within the May Valley Urban Separator contiguous-open-space-corridor of which, Stonegate Tract A wetland is a part. (Reference City of Renton map, December 17th, 2004). I ask the Hearing Examiner to follow the precedence set by your predecessor and require split rail fences around the wetland buffer's perimeter, if this Master Application is ever approved. Frankly, I am surprised that the City is pressing ahead with this application. City staff is a scarce resource in this era of restricted public budgets. Processing this application incurs staff and material costs, yet the project is not design finalized, nor sanctioned by all permitting agencies. More Questions: Where is the broad citizen support for this expenditure of public funds to benefit a few private interests? This project is to benefit four horse pastures at the risk of many downstream homeowners. Other than county staff, how many citizen dredging proponents testified at the hearing? (See footnote 2.) Where is the state, federal and tribal support? Ecology has denied water quality certification. The Muckleshoot Tribe's opposition is on record. The United States Army Corps of Engineers has concerns and unanswered questions. The Army Corps has not yet made a determination under the Federal Clean Water Act, Essential Fish Habitat nor the Endangered Species Act. Of note, the Army Corps has been reviewing this proposal since September 2010! (See copy enclosed.) Can this project pass a cost benefit analysis? If so, where is it? This proposal has no economic value to the City of Renton or its citizens. In fact, there is the possibility of downstream liability to the environment, and public and private infrastructure. This could result in far reaching lawsuits. I urge the City wait until this project has been fully justified and designed. The State Dept. of Ecology is not satisfied with the proposal including the mitigation in the wetland within Renton City limits. More mitigation will be required, which could expand the clearing and grading footprint. The project is not yet fully designed. In good faith, the city cannot grant a Critical Areas Variance for a proposal that is incomplete. A proposal that has been denied Section 401 Water Quality Certification by the State. A proposal that has not yet had a decision rendered by the Army Corps of Engineers under Section 404 of the Clean Water Act. I urge the Hearing Examiner to read and give full weight and consideration to Dr. Olson's memo and the Department of Ecology'S letters of September 1st and the subsequent denial of September 22Dd, 2011. Please wait until the state, the feds and the Muckleshoot are satisfied that there will be no adverse impacts to Renton citizens' property, public infrastructure and the environment. I ask that the City of Renton defer to the wisdom, expertise, and experience of the Washington State Dept. of Ecology. I ask that the City insist that the project be fully engineered to the satisfaction of all public and private stakeholders. Please deny the Critical Areas Variance. Please deny the Special Grade & Fill Permit. Thank you for your thoughtful deliberations. Andre Attachments: Five FOOTNOTES: I. Excepted from August 15th, 2011 internal state Department of Ecology memo from Patricia 1. Olson, Senior Hydrogeologist, PhD, LHG. "King County's Department of Natural Resources, Water and Land Resources Division have well qualified fluvial geomorphologists and geologists. The proponents of this project and the geomorphologists and geologists are in the same division. However, these qualified people appear to not have been consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomorphic processes that created the current conditions, and downstream channel response including migration to changes in flow and sediment regimes. The expertise is available within the same King County department and division. These people should be consulted on this project: 2. There are seven properties adjacent to May Creek within River Mile 4.3 an 4.9, the proposed project reach. One of these properties is a dedicated open space wetland; a second is an undeveloped-unused property that is obviously a wetland; and a third is not used for farming activity of any kind. The remaining four properties have horse pastures within the seasonally flooded wetlands. None of the homes on these properties is in danger of flooding. . Converselv. between Nile Avenue NE (ak.a. 148 th Avenue SE) and Coal Creek ParkwRy there are 18 homes along the creek and two at-risk sole-access-private-bridges. At least eight of these homes are within 20 to 50 feet of the unstable creek banks and/or close enough to experience flooding. There are also a half a dozen homes down in the flood prone May Creek canyon and the public and private infrastructure at the mouth of May Creek (Barbee Mills). / . Gerald Wasser From: Sent: To: Jennifer T Henning Thursday, September 15, 2011 2: 19 PM Gerald Wasser EXHIBIT 23 Subject: FW: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 401c and CZM Attachments: May Creek Dredging 401c and CZM Public Notice comments. pdf From: Karen Walter [KWalter@muckleshoot.nsn.usJ Sent: Thursday, September 15, 2011 2:06 PM To: ECY RE FED PERMITS Cc: Lull, Lori C NWS; Randy McIntosh; 'Fisher, Larry D (DFW)'; Padgett, Rebekah (ECY); McGraner, Patrick (ECY); Dave Garland; Jennifer T. Henning; Chin, Doug; Hartley, James Subject: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 481c and CZM To Whom It May Concern, Attached you will find comments from the Muckleshoot Indian Tribe Fisheries Division in response to the Public Notice of Application for the above referenced project. A signed hard copy has also been sent to the Olympia office of Ecology. Please let me know if you have any questions. Thank you, Karen Walter Watersheds and Land Use Team Leader Muckleshoot Indian Tribe Fisheries Division 39815 172nd Ave SE Auburn, WA 98892 253-876-3116 1 - · MUCKLESHOOT INDIAN TRIBE Fisheries Division 39015 -172"d Avenue SE • Aubum, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 May 11,2011 Washington Department of Ecology-SEA Program Federal Project Coordinator P.O. Box 47600 Olympia, WA 98504 RE: May Creek Drainage Improvement Project 401c and CZM Consistency Public Notice of Application. Dear Sir or Madame: The Muckleshoot Indian Tribe Fisheries Division (MITFD) has reviewed the Public Notice of Application for a State of Washington 401 Water Quality Certification and Coastal Zone Management Act Consistency for the May Creek Drainage Improvement Project. This project is the first of potentially four phases to dredge May Creek. In this first phase, the project proposes to dredge May Creek from Rivermile 4.3 to Rivermile 4.9, removing sediments, reed canarygrass and some of the existing willows that are within the flooded area of concern. As noted in previous comments, the MITFD has expressed concerns about proposals to dredge May Creek because of potential adverse impacts to salmon and their habitats. This project proposes to dredge 2,000 linear feet of May Creek and its associated wetland in areas identified as salmon spawning and rearing habitat (May Creek Baseline Stream Conditions Report). As noted in various May Creek documents reviewed, this is the first dredging proposal of potentially four projects that would result in the dredging of 2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. The combined impact of all of these dredging projects would likely result in a significant loss of existing salmon habitat, and potentially future adverse impacts upstream and downstream from the dredged reaches as other landowners seek to protect their properties from bank erosion. We recommend that King County implement and exhaust all less impacting alternatives prior to dredging May Creek. We remain concerned that this project will adversely affect salmon and aquatic habitats without sufficient mitigation for these impacts. The project proposes to directly impact the natural process of sedimentation and floodwater storage along May Creek without adequately assessing the potential impacts to salmon and their habitat in the project area and in upstream and downstream areas. In particular, the potential pre-and post-project rearing habitat available for juvenile salmon in May Creek has not been quantified .. Furthermore, for those impacts which have been quantified, the project impacts exceed the proposed mitigation in length and area. While the proposal to fence and plant native wetland! riparian vegetation I I' .,." .. Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401c and CZM Public Notice - -------------------- May 11, 2011 Page 2 . and create alcoves with wood and sediment is an improvement over the existing conditions for most of the project area, the extent of these mitigation' measures is insufficient to mitigate for the potential loss of 48,000 square feet ofinstream habitat as a·result of this dredging project. The planting buffer is significantly less than the regulated buffer and would provide inadequate riparian functions as a result. Additional mitigation for this project will likely be required to fully mitigate for the unavoidable environmental impacts from the project. Mitigation should include maximizing the natural processes that create and sustain salmon habitat including: I) improving pasture conditions and controlling other existing sediment sources through agricultural best management practices, farm conservation plans, and other measures as appropriate; 2) greatly minimizing the dredge area; 3) adding additional habitat mitigation to the dredged portion; 4) increasing the streamlwetland buffer width to the regulated 25 foot buffer width and increase riparian plantings; 5) avoid impacting downstream portions of May Creek; and 6) mitigating any unavoidable impacts to downstream areas. We are concerned that this project is a "short term fix" and that there is a high I.ikelihood that additional dredging will be proposed elsewhere and/or in the future that may again adversely affect May Creek, its associated wetlands, and potentially the mitigation implemented for this project. Instead we recommend focusing more effort on the obvious land use and pasture~ related sediri:tent sources and aiIow the May Creek more room to store and transport its sediment load, consistent with natural stream processes. Additional specific comments and questions about this project are attached for your review and consideration. Please let me know if you have any'questions at 253-876-3116. Sincerely, KMw\V~ Karen Walter Watersheds and Land Use Team Leader Cc: Lori Lull, USACOE Randy McIntosh, NMFS Larry Fisher, WDFW Region 4 Rebekah Padgett, WDOE, NW Region Patrick McGranger, WDOE, NW Region Dave Garland, WDOE, NW Region Jennifer Henning, City of Renton Planning Doug Chin, King County DNRP Jamie Hartley, King County DDES Mucklesho011ndian Tribe Fisheries Division Commen1s 10 May Creek Dredging 401 c and CZM Public No1ice Other Potential Alternatives . May 11, 2011 Page 3 We are concerned that King County has not fully pursued all available alternatives that could reduce the need to dredge the entire area proposed under Phase I (and future phases) and reduce the amount of native vegetation removals to better protect existing instream and riparian functions. For example, most of the properties that would benefit from Phase I dredging are used for livestock pasture. King County Code (Title 21.AJO) regulates these areas to "support the raising and keeping of livestock in the county in a manner that minimizes the adverse impacts of livestock on the environment particularly with regard to their impacts on water quality and salmonidfisheries habitat in King County watersheds". It is not clear how the adjacent properties are in compliance with this code which limits the maximum number of livestock on a per acre basis. As part of the Code compliance, property owners are required to have a farm plan with maximum densities of livestock. These farm plans require: "Site-specific management measures for minimizing nonpoint pollution from agricultural activities and for managing wetland and aqU£Jtic areas including, but not limited to: a. livestock watering; b. grazing and pasture management; c. confinement area management; d manure management; and e. exclusion of animals from aquatic areas and their buffers and wetlands and their buffers with the exception of grazed wet meadows. " (KCC 21A.30.045.2). It should be noted that KCC 21.AJO.045.B requires that farm management plans seek to achieve a "minimum 25 foot buffer of diverse, mature vegetation between grazing areas.and the ordinary high water mark of all type S and F aquatic areas and the wetland edge of any category I, II or III wetland with the exception of grazed wet meadows, using buffer averaging where necessary to acco=odate existing structures." The proposed mitigation buffer for dredging is a maximum of 15 feet that is substantially less that the County Code. Another problem is that the mitigation buffer area is not proposed to be permanently protected in a conservation easement. From our field visit on April 26, 2011, it appears that the properties in question are not complying with King County Code Title 2I.A.30. Prior to the approval of any dredging proposal that will adversely impact salmon habitat in May Creek, we reco=end that the properties demonstrate compliance with Title 21.A.30 in that the property owners have minimized their contributions to the sedimentation and flooding problem, including providing a vegetated buffer to control sediment loading and shading out the existing reed canarygrass in and along May Creek and its tributaries. The project should also evaluate the potential for the existing SE 14 81b Street Bridge to create an obstruction and create backwater conditions that cause sediment to deposit upstream. Per the Hydraulic and Hydrologic Analyses for the project (December 2010), this bridge cannot pass a 100-year flood without overtopping the roadway. I I Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice Project benefits May 11, 2011 Page 4 The purpose of the project is to reduce the duration of flooding on local property owners by removing in- stream channel obstructions. There should be further analysis that discusses how much used pasture area will have reduced flooding and for what duration for each of the affected properties to determine project impacts versus potential benefits. The Hydraulic and Hydrologic Analysis report suggests that the decrease in flood durations at 100 cfs is 7 hours which suggests little benefit for substantial environmental impacts to May Creek. Project Impacts We are concerned that the existing rearing habitat in May Creek will be lost through the combination of channel dredging, reed canarygrass removal, and removal of in-water and adjacent willows. There is no estimate given for the potential loss of rearing habitat. However, the impact analysis indicates that the total impact area is 43,995. square feet (1.01 acres), whereas, the proposed mitigation area at the two off- channel alcoves is 10,238 square feet (0.24 acres). This is less than a I: I ratio of impact to mitigation area and will likely result in unmitigated impacts to existing rearing habitat for juvenile sa:!mon. In addition, details are lacking regarding the flood event needed to connect the alcoves to May Creek, the corresponding water depth in the alcoves, how long they will be inundated, and how much rearing habitat would be created. If the alcoves are not fully connected to May Creek or the entire area is not inundated, then the mitigation area alcoves may actual provide less habitat than the proposed 10,238 square feet and also may potentially result in stranding mortality. The project has not adequately described or analyzed the sediment sources coming into May Creek from Long Marsh Creek. For example, it is not clear if undersized culverts on Long Marsh Creek are contributing to bank erosion and contributing to the sediment load. Alternatively, upstream stormwater contribution may be causing sediment transport in Long Marsh Creek too. Additional information is needed to assess the contribution from Long Marsh Creek and if needed, measures taken since Long Marsh Creek was identified a major contribution in the County's sediment assessment report. Finally, we do not view the proposed Long Marsh Creek work as mitigation for reasons noted below. It is also unknown what benefit, if any, would occur from creating a side channel at the Long Marsh/May Creek confluence to trap sediment. It seems likely that this constructed feature would fill in from upstream sediment, since the mitigation design is not providing sufficient width in the upstream portions of Long Marsh Creek to slow down the rate of sediment transport and retain sediment in the channel upstream. In addition, the proposal to remove existing red alders that are 10-15 years old with smaller trees in the same 15 foot wide buffer on Long Marsh Creek is an impact, not mitigation. The project may not have fully considered potential impacts to Chinook, coho, and sockeye salmon. According to the Stream and Wetland Impact Analysis and Mitigation Plan, King County indicates that chinook and sockeye salmon do not travel upstream as far as May Valley. However, King County has data from the Salmon Watcher's program that indicates that adult Chinook, sockeye, and coho were reported as far upstream as Greene's Creek in 2001, which is just downstream of the SE 1481h bridge. (see http://your.k.ingcounty.gov/dnro/library/archive- Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice documentsfwlrfwaterresfsalmoniMapsf200 If0205distroEASTIake W Apdf). May 11, 2011 PageS The project also needs to mitigate for the loss of the full channel spa.nnillg pool at the Long Marsh Creek confluence. This pool will be eliminated by the stream dredging and not replaced based on the proposed mitigation plans. Since pools are limited in this portion of May Creek per the baseline stream conditions report, the pool should be replaced, potentially downstream of SE 148 th adjacent to the NGPE tract for Stonegate where there are fewer constraints . . Alluvial fans are natural features at Long Marsh Creek and farther upstream at Indian Meadow Creek. According to the sediment assessment report, these features have been documented in the May Creek Valley since 1872. As a result, they will likely be continued sources of sediment to May Creek. Phase I and the future phases need to develop strategies that accommodate these natural features instead of proposing dredging now and into the future. The project may also aggravate existing conditions for water temperature and dissolved oxygen in May Creek. Currently May Creek through the May Valley is shown as a "Category 2" water for temperature and dissolved oxygen on Ecology's 2008 303(d) list. The removal of vegetation along 0.6 miles of May Creek that currently provides shade may worsen this condition. Once a redesigned project has been 'developed that addresses the concerns above, then a water quality protection plan and a monitoring plan that assesses the project's effects on sediment transport/filling, flooding, habitat creation and riparian planting success can be developed. Any approved project should be monitored for 10 years to determine project success ( or failure) prior to allow any new dredging. I -------------------- EXHIBIT 24 US Army Corps of Engineers Seattle District Joint Public NotIce e Illlt .. l .. $llll Hltll.Elf " ECOLOGY Application for a Department of the Army Permit and a Washington Department of Ecology Water Quality Certification and/or Coastal Zone Management Consistency Concurrence US Army Corps of Engineers Regulatory Branch Post Office Box 3755 Seattle, Washington 98124-3755 Telephone (206) 766-6438 Attn: Lori C. Lull, Project Manager WA Department of Ecology SEA Program .. Post Office Box 47600 Olympia, Washington 98504-7600 Telephone (360) 407-6068 Name: Attn: SEA Program, Federat Permit Coordinator Interested parties are hereby notified that the U.S. Army Corps of Engineers (Corps) and the Washington Department of Ecology (Ecology) have received an application to perfonn work in waters of the United States as described below and shown on the enclosed drawings. The Corps will review the work in accordance with Section 404 of the Clean Water Act (CWA). Ecology will review the work pursuant to Section 401 of the CWA, with applicable provisions of State water pollution control laws and the Coastal Zone Management Act. APPLICANT: King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, Washington 98104-3855 Attention: Doug Chin Telephone: (206) 296-8315 LOCATION: In May Creek and wetlands abutting May Creek at Renton, Washington WORK: The work includes removal of sediment from 2,000 linear feet of May Creek and clearing of reed canarygrass and willows from ·8500 square feet of the May Creek channel. Sediment removal will be done with a trackhoe or similar equipment. A portion of material removed from the streambed will be stockpiled, dried, and spread in adjacent upland horse pastures. Excess sediments and material that is removed with reed canary grass will be disposed of offsite at an undetermined upland location. Construction impacts will also include placement of quarry spalls in approximately 7550 square feet of wetlands for a temporary access road: After construction is complete (approx. 10 days), this fill will be removed and the area will be replanted with native vegetation . . MITIGATION: The applicai1t has proposed mitigation to offset negative impacts to in-stream fish habitat. The mitigation includes a 15 foot buffer of native riparian and wetland planting on both sides of May Creek (1.3 acres), enhancement of 3.75 acres of wetland on the west side of 148th Avenue Southeast, which includes excavation and placement of streambed gravel in approximately 0.7 acre along the channel of May Creek to create off-channel NWS-2010-158 alcoves. If an easement is granted, mitigation will also include excavation and placement of streambed gravel and Large Woody Debris, impacting 150 linear feet at the confluence of Long Marsh Creek and May Creek. PURPOSE: The applicant has stated that the purpose is to reducethe duration of flooding in pastures on rural residential properties. ENDANGERED SPECIES: The Endangered Species Act (ESA) requires federal agencies to consult with the National Marine Fisheries Service (NMFS) andlor U.S. Fish and Wildlife Service (USFWS) pursuant to Section 7 of ESA on all actions that may affect a species ,listed (or proposed for listing) under the ESA as threatened or endangered or any designated critical habitat. After receipt of comments from this public notice, the Corps will evaluate the potential impacts to proposed andlor listed species and their designated critical habitat. ESSENTIAL FISH HABITAT: The Magnuson-Stevens Fishery Conservation and Management Act, as amended by the Sustainable Fisheries Act of 1996, requires all Federal agencies to consult with the NMFS on all actions, or proposed actions, permitted, funded, or undertaken by the agency, that may adversely affect Essential Fish Habitat (EFH). The proposed action would impact EFH in the project area. If the Corps determines that the proposed action may adversely affect EFH for federally managed fisheries in Washington waters, the Corps will initiate EFH consultation with the NMFS. The Corps' final determination relative to project impacts and the need for mitigation measures is subject to review by and coordination with the NMFS. CULTURAL RESOURCES: The District Engineer has reviewed the latest published version of the National Register of Historic Places, lists of properties determined eligible and other sources of information. No known historic properties occur in the vicinity of the proposed project. Due to the project's location in the landscape (i.e. adjacent to a river), there is a high likelihood that unknown historic properties occur in the project area. An historic properties investigation may be required during the pennit review. The District Engineer invites responses to this public notice from Native American Nations or tribal governments; Federal, State, and local agencies; historical and archeological societies; and other parties likely to have knowledge of or concerns with historic properties in the area. This public notice initiates consultation under Section 106 of the National Historic Preservation Act with any Tribe that has information or concerns with historic properties in the proposed permit area. EV ALUA TlON -CORPS: The decision whether to issue a permit will be based on an evaluation of the probable impacts, including cumulative impacts, of the proposed activity on the public interest. That decision will reflect the national concern for both protection and utilization of important resources. The benefits, which reasonably may be expected to accrue from the proposal, must be balanced against its reasonably foreseeable detriments. All factors which may be relevant to the proposal will be considered, including the cumulative effects thereof; among those are conservation, economics, aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood haZards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, considerations of property ownership, and, in general, the needs and welfare of the people. The Corps is soliciting comments from the public; Nati~e American Nations or tribal governments; Federal, State, and local agencies and officials; and other interested parties in order to consider and evaluate the impacts of this activity. Any comments received will be considered by the Corps to determine whether to issue, modify, condition or deny a permit for the work. To make this decision, comments are used to assess impacts on endangered species, historic properties, water quality, general environmental effects, and the other public interest factors listed above. Comments are used in the preparation oran Environmental Assessment andlor an Environmental Impact Statemerit pursuant to the National Environmental Policy Act. Comments are also used to determine the need for a public hearing and to determine the overall public interest of the activity. 2 NWS-20 I 0-158 The described discharge will be evaluated for compliance with guidelines promulgated by the Environmental Protection Agency under authority of Section 404(b)(I) of the CW A. These guidelines require an alternatives analysis for any proposed discharge of dredged or fill material into waters of the United States. EVALUATION-ECOLOGY: Ecology is soliciting comments from the public; Federal, Native American Nations or tribal governments, State, and local agencies and officials; and other interested parties in order to consider and evaluate the impacts of this activity. Ecology will be considering all comments to determine whether to certifY or deny certification for the proposed project. COMMENT AND REVIEW PERIOD: Conventional mail or e-mail comments on this public notice will be accepted and made part of the record and will be considered in determining whether it would be in the public interest to authorize this proposal. In order to be accepted, ewrnail comments must originate from the author's e- mail account and must include on the subject line of the e-mail message the pennit applicant's name and reference number as shown below. Either conventional mail or e-mail comments must include the permit applicant's name and reference number. as shown below, and the commenter's' name, address, and phone number. All comments whether conventional mail or e-mail must reach this office, no later t an-lfle-el<P; date of this public notic~ to ensure consideration. Corns Comments: All e-mail commentsshouldbesentolori.c.lull@usace.army.mil. Con ntional mail comments should be sent to U.S. Army Corps of Engin ers, Regulatory Branch, Attentio . Lori C. Lull, Post Office Box 3755, Seattle, Washington, 98124-3755. Ecology Comments: Any person desiring to present views on the project pertaining to a request for water quality certification under Section 401 of the CW A and/or Coastal Zone Management consistency concurrence, may do so b ·subilllttmg wntten com to the following address: Department of Ecology, Attention: SEA program- Federal Permit Coordinator, Post ffice Box 47600, Olympia, Washington, 98504-7600, or e-mail to ecyrefedpermits@ecy.wa.gov To ensure proper consideration of all comments, responders must include the following name and refercnce number in the text of their comments: King County (May Creek); NWS-201 0-158 Encl: Figures (8) 3 1 -------I THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATURES SHOWN ON THIS PLAN ARE FROM G.i.S. REDUCE DURAll ON OF FLOODING ON PROPERllES ADJACENT TO MAY CREEK; BETWEEN APPROX. RIVER MILE 4.3 AND 4.9. TO SHE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AVE S.E.. TURN SOUTH TO BRIDGE OVER MAY CREEK. N.A. ON THIS SHEET MAY CREEK DRAINAGE SCALE: H: 1" = 2000' ASSISTANCE BY: liNDSEY MILLER DRAWN B~ RADELLA ~ King County REMOVE FLOW OBSllRUCllNG VEGETAllON AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NA llVE VEGETA llON ON BOTH SIDES OF CHANNEL ENHANCE OFF-CHANNEL WETLAND FISH HABITAT DOWNSllREAM OF 148TH S.E. SHEET: 1 OF 8 DATE: AUG 13, 201 0 -----------~----------------------------------------------------------------- .. v" --- "-...... ----... ..... ,/ "~~. "'-' ',~~-)~ .. , •• <e'" • , ... ~ ,~,,/ \ '. v· (' \ ' . [\"/",\. ~)-tC" , ,) i U DESIGN lEGEND ~M SEDIMENT REMOVAL AREA ~ .. /' . MITIGATION WORK AREA ~ WITH ALCOVES --'--WETLAND BUFFER (110') .STREAM BUFFER (165') --- PLANTING MITIGATION LINE (15' BUFFER) . EXISTING lEGEND . . -.. -.. -TOE (BOTTOM) OF STREAM --DRIVEWAY UNE . FENCE SURVEY CONTROL ---PROPERTY UNES ------R-O-W UNES .v . ,,, ---'--oEUNEATED WETlAND SlIT: I AND PHYSICAL THIS PLAN ARE BASED OF FIELD OBSERVATIONS FROM CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S,E. MAY VALLEY ROAD, GO TO 148TH AVE S.E., TURN TO BRIDGE OVER MAY CREEK. WASHING STATE LAMBERT GRID 1" = 200' '. -". ' ... " 0+00 -15+00 / 91; NAW 88 ASSISTANCE BY: UNDSEY MILLER DRAWN BY: MEREDITH RADELLA ~"-" ~~,-.. '. '. \ \.~ '-" . ------------------, . ....... ~ King County REMOVE FLOW OBSTRUCTING VEGETATION AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NAllVE VEGETAilON ON 80lH SIDES OF CHANNEL ENHANCE OFF-CHANNEL WETLAND FISH HABITAT DOWNSTIREAM OF 148TH S,E. SHEET: 2 OF 8 DA IT: AUG 13, 201 0 \ \ \ EXISTING TOPOGRAPHIC AND PHYSICAL '~t~'~~~~SH~:O~lWN ON THIS PLAN ARE BASED I~ I OF FIELD OBSERVATIONS InIO"r'nf"'~ TO SITIE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD, GO TO 148TH AVE S.E .. TURN SOUTH TO BRIDGE OVER MAY CREEK. WASHING STATIE LAMBERT GRID / 91; NAVD 88 -':::20"'"0------.J0 200 SCALE IN FEET SHEET TITLE: PLAN VIEW STA. 15+00 -29+00 SCALE: 1· = 200' ASSISTANCE BY: UNDSEY MILLER DRAWN BY: MEREDITH RADELLA \ \ \ \ \ '\ \ W King County REMOVE FLOW OBSTRUCTING VEGETATION AND SEDIMENT FROM MAY CREEK, PlANT 15' BUFIFIER OF NATIVE VEGETATION ON BOTH SIDES OF CHANNEL ENHANCE OFIF -CHANNEL WETLAND FISH HABITAT DOWNSTREAM OF 148TH S.E. 3 OF 8 AUG 13, 2010 TYPICAL SECTION: SEDIMENT REMOVAL "'r--.. :... . t--'----I _;325.0 I_ i . i· ···1 .. CUT AND REMOVE WlUOW , :.: . .31.i:Lb. f. . ... t . ... _·t ·--l ,_305.00,_ .. + 25100 . -20;00' 1" = 10' TYPICAL SECTION: VEGETATION REMOVAL URPOSE: REDUCE DURATION OF FLOODING ON PROPERTIES ADJACENT TO MAY CREEK; BETWEEN APPROX. RIVER MILE 4.3 AND 4.9. IRECTIONS TO SITE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD. GO TO 146TH AVE S.L, TURN SOUTH TO BRIDGE OVER MAY CREEK. ATUM: AS STATEO 1" -= 10' PROJECT TITLE: MAY CREEK DRAINAGE-IMPROVEMENT SHEET TITI£: SECTION VIEWS SCALE: NOT TO SCALE ASSISTANCE BY: UNDSEY MILLER ORA ~ BY: t.tEREDITH RADELLA T ---20;00--25100 W King County ROPOSED WORK: REMOVE FLOW OBSTRUCTING VEGETATION AND SEDIMENT FROM t.tA Y CREEK. PLANT 15' BUFFER OF NATIVE VEGETATION ON BOTH SIDES OF CHANNEL. ENHANCE- OFF-CHANNEL WETLAND FISH HABITAT DOWNSTREAM OF 146TH A S.E. SHEET: 4 OF 8 DATE: AUG 13, 2010 l' ~BOYE' I: ::::::'::.: I l~;;~'i~~r~'~"""': ................ , ............... "'I1RAOE'A1;CO\IE'S:5X"(18:1)' Ib .. OOCH ...... · .. · .. · .. , ... ..... ., :: :: EXISTING GROUND APPROX, '105! . : . : I .,. . , .. · ................ ' .. ·FRQM'LOW·PO)NT·pF·CHANNEL' .... , ........ ·, .. . :. ::.' . .::':' HABITAT MITIGATION ALCOVE GRADING 1" ~ 20' LWD INSTALLATION NOTES: THE FOLLOWING METHODS OR COMBINATIONS THEREOF WILL BE USED TO REDUCE MOBIUlY OF LWD: • EMBEDMENT OF 50 PERCENT SURFACE AREA OF LOGS AND WILLOW ANCHOR POLES • TRENCH/BURY 60 PERCENT OF LOG LENGTH PINNING OF LOGS AND ROOTWAOS BEHIND .EXISTING TREES GREATER THAN 12" DIAMETER IN COMBINATION WITH PARTIAL TRENCHING OF lOG hIQ'>r.'''N~ TO SITE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E, MAY ROAD. GO TO 148TH AVE s.£., TURN TO BRIDGE OVER MAY CREEK. AS STAllED HABITAT LOG MITIGATION PLACEMENT 1" ~ 50' TITLE, I ":",:;:;,,.;~ VIEWS SCALE, NOT TO SCALE ASSISTANCE BY: UNDSEY MILLER BY: MEREDITH til King County FLOW OBSTRUCTING VEGETATION AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NATIVE VEGETATION ON BOTH SIDES OF CHANNEL ENHANCE OFF-CHANNEL WETLAND nSH HABITAT DOWNSTREAM OF 148TH S.£. SHEET: 5 OF B DAllE: AUG 13, 2010 • M mGATION PLAN NOTES (A) CON~TRUCTION NOTES 1. mEES TO BE PRESERVED WILL liE FlAGGED IN THE FlELD BYTHE ECOUGIST. 2. INSTALL SILT FENCES WHERE DESIGNATED ON THE PlANS. INSTALL t>m OTHER EROSION AND SEDIMENT CONffiOL MEASURES AS REQUESTED BY THE ENGINEER 3. ELEVATION SHOWN ARE FlNAL GRADE, 4 TO 6 INCHES OF OVER-X WILL OCCUR AND BE BACKFILLED FlLLED WITH SffiEAMBED GRAVELS OR COMPOST ON AREA 4. EXCAVATION ADJACENT TO THE STREAM CHANNEL SHALL TAKE PLACE ONLY DURING THE FlSH WINDOWS AS DESIGNATED IN THE PERMITS. WHEN EXCAVATING ADJACENT THE STREAM CHANNEL AN EARTH PLUG SHALL BE LEFT BETWEEN THE EXISTING STREAM CHANNEL AND THE EXCAVATION AREA. PRIOR TO REMOVING THE EARTH PLUG AND CONNECTING THE EXCAVATED CHANNEL, A TURBIDnY CURTAIN SHALL BE INSTALLED AS SHOWN IN THE DETAILS TO PROTECT THE STREAM FlROM SEDIMENT AND TURBIDITY DURING CONNECTION. S. IF ANY GROUNDWATER IS ENCOUNTERED DURING EXCAVATION, DEWATER BY PUMPING AND BROAOCASTING TURBID WATER THROUGH SILT FENCE AND DISSIPATED OVER VEGETATED STRIP IN UPlAND AREAS OF THE SITE 6. ELEVATIONS ASSOCIATED WITH CONTOURING ALCOVE AND FLOODPLAN AREAS IS TO BE DIRECTED BY ECOLOGIST IN THE FlELD. 7. PARTIIALLY BURY AND PLACE LOGS IN THE EXCAVATED ALCOVE, LOG PLACEMENT SHOWN IN THE PLANS ARE SCHEMATIC; ACTUAL PLACEMENT AND ARRANGEMENT TO BE DETERMINED BY THE ECOLOGIST IN THE FlELD. INSTALL 2" DIAMETER WILLOW AND COTTONWOOD ANCHORING POLES AS SHOWN IN THE PLAN DETAlLS. 8. PLACE 6 INCHES OF STREAMBED GRAVELS WITHIN THE ALCOVE AREA. 9. PLACE LOGS IN THE FLOOPLAIN, LOG PLACEMENT SHOWN IN THE PLANS ARE SCHEMATIC; ACTUAL PLACEMENT AND ARRANGEMENT TO BE DETERMINED BY .THE ECOLOGIST IN THE FlELD. INSTALL 2" DIAMETER WILLOW AND COTTONWOOD ANCHORING POLES AS SHOWN IN THE PLAN DET>JLS. 10.PLANT EMERGENTS AND SHRUBS ACCORDING TO PLANTING PLAN. 11. REMOVE TEMPORARY STABIUZED CONSffiUcnON ENTRANCES AND REMOVE HIGH-VlSIBILnY FENCES, AND ANY OTHER EROSION CONTROL MEASURES STILL INSTALLED AT THE SITE. 12. CONTRACTOR SHALL PROVIDE STREAM ISOLATION / TURBIDnY CURTAIN PER WASHINGTON DEPARTMENT OF ECOLOGY STANDARDS. SEE SHEET 7 FOR PlANTING NOTES. PURPOSE: REDUCE DURATION OF FLOODING ON PROPERTIES ADJACENT TO MAY CREEK; BETWEEN APPROX. RIVER MILE 4.3 AND 4.9. PIRECTIONS TO SITE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AVE S.E., TURN SOUTH TO BRIDGE OVER MAY CREEK. PA TUM: AS STATED N~ 7.o1~1t;fi .~ King County PROJECT TITLE: PROPOSED WORK: MAY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING SHEET 11M: MIllGAllON NOTES SGALE: NOT TO SCALE ASSISTANCE BY: UNDSEY MILLER DRAWN BY: MEREDITH RADELLA VEGETATION AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NAllVE VEGETAllON ON BOTH SIDES OF CHANNEL ENHANCE OFF-CHANNEL WETLAND FlSH HABITAT DOWNSTREAM OF 148TH AVI S.E. SHEET: 6 OF 8 DATE: AUG 13, 2010 M [[]~AIIQ~ ~I.l\~ ~QIf;~ CONTINUED (B) PlANTING NOTES 1. MITIGATION PLANTING PLANS REPRESENT A CONCEPTUAL PLANT LAYOUT. All MITIGATION PLANTING PREPARATION WILL BE DIRECTED IN THE FIELD BY THE ECOLOGIST. 2. PLANTING SHALL TAKE PLACE DURING THE DORMANT SEASON (NOVEMBER 1 ST THROUGH FEBRUARY 28TH). PlANTING MAY BE ALLOWED AT OTHER TIMES AFTER REVIEW AND WRmEN APPROVAL BY THE ECOLOGIST. 3. WITHIN THE FLOODPlAIN EXCAVATION AREAS AND ALL PLANTING AREAS WHERE REED CANARYGRASS HAS BEEN COMPLETELY REMOVED, PROVIDE AND INSTALL 4 INCHES OF COMPOST (PER SPEC) RDTOTILLED TO A (12) INCH MINIMUM. 4. IN ALL PLANTING AREAS WHERE REED CANARYGRASS IS PRESENT, FlRST MOW .THE GRASS. COVER MOWED REED CANARYGRASS WITH CARDBOARD (OR A SIMILAR BARRIER MATERIAL AS APPROVED BY THE ECOLOGIST) FOLLOWED BY 6 INCHES OF COMPOST. S. PLANT SHRUBS AND TREES THROUGH THE CARDBOARD AND COMPOST AS DIRECTED BY THE ECOLOGIST. 6. All PLANTS SHALL BE NURSERY GROWN A MINIMUM OF ONE YEAR. PLANT MATERIAL IS TO BE SUPPLIED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PLANTS NATIVE TO THE PACIFIC NORTHWEST. PLANT MATERIAL SUBSTITUTIONS ARE SUBJECT TO APPROVAL BY THE ECOLOGIST. 7. NO TACKIFER, HERBICIOE, OR FERTILIZER SHALL BE USED IN THE PLANTING AREAS. (e) GENERAL NOTES 1. TO PREVENT REESTABUSHMNET OF INVASIVE VEGETATION, THE TOP 24 INCHES OF EXCAVATED SOIL IS NOT TO BE REUSED AS FILL ANYWHERE ON THE PROJECT SITE. 2. DO NOT DRIVE EQUIPMENT IN AREAS OF THE SITE WHERE COMPOST HAS BEEN MIXED INTO THE NATIVE SOIL. May Creek Riparian Buffer Planting. east of 148th Ave SE latin Name Common Name SIze/Speclflcations Quantity T_ ....... ~-\"Oo!ipct@os.rllolJlIl '" I'IaoIVO-C -....... --un. 5"" u.;"" Ful 0.... folio.., '''' ,. .. .,'Oc. 1qM1lS~1I'P---1·~@l6-I' HeiIloE Si.pS1ralp.. Troak '" m-,. ...... vo.e. --W_nd ...... BAlI, J4' llei"u l'1li1 DeNt Yolias* '" ......,.oc. ShrubsIWlllow8 eo", .. _ Rtd ... io<r~ . wu.; .. ~ 11-b>tSprad~4~llm_ ,~ PIu!6'Oc. -~-hcilicnZoobori: :u-H"'~ II" _Spo-'M-..' ..... llMo .... ftu1f1 = 0"-_ ..... --,,.. Hd,u. II"""" SpnoodMiloimum4 ...... l v.._ = i'bot6'O,c, .... _. ---2,..a<ip.l.ll" ...... SpnodW .......... r..;p.lu.._ = 1'bM6'QC u..~~36"l.oq"ll2.I·~ s..1z"-" "*"Sc,..;a".. Wio ....... 'IMIo.5I ~ P1Dt4'o.C. Lin$btQ.MiIoimoro.Wi.<lqlll.I-~ :rt1IU1I:tJIIkri""" tIoDuIcr'lwillN WiUIr=. 6 .... bad! ~ PIaooH'O.C. GroundcoVGr ij1 ~""""".1Jb.}DIri .. _. ....,m '" ...... ,....,t~4....u ~' qtr:1~-1'1U14'o.C. 8It%u'l'i=r ...... r ..... ,.. ... MiooiIauaa4_ ~ ~ ingCounty PbnI4'O,C. URPOSE: REDUCE DURATION OF FLOODING PROJECT TITLE: ROPOSED WORK: ON PROPERTIES ADJACENT TO MAY CREEK; MAY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING BETWEEN APPROX. RIVER MILE 4.3, AND 4.9. VEGETATION AND SEDIMENT FROM PIRECTIONS TO SITE: SHEET TITLE: MAY CREEK. PLANT 15' BUFFER OF NATIVE VEGETATION ON BOTH SIDES FROM COAL CREEK PARKWAY, (EAST OF PLANl1NG NOTES AND TABLE OF CHANNEL. ENHANCE 1-405) lURN EAST ON S.E. MAY VALLEY OFF-CHANNEL WETLAND FISH ROAD. GO TO 148TH AVIE S.E., lURN SOUTH HABITAT DOWNSTREAM OF 148TH AVI TO BRIDGE OVER MAY CREEK. pAlUM: AS STATED SCALE: NOT TO SCALE S.E. ASSISTANCE BY: LINDSEY MILLER SHEET: 7 OF 8 I NW~-lOrQ~\~ DRAWN BY: MEREDITH RADELLA DATE: AUG 13. 201 0 . , ------~ LOG TABLE # of LOGS LOG SIZE LOG ROOlWAD OR LENGTH WITHOUT (W/OUT) flOODPLAIN ROUGHNESS 30 12~-14·dbh 30' w/out " 30 12"'-lS'"dbh 30' rootwods 60 totol ALCOVE AREAS 7 16"'-2."' dbh 30' rootwods 5 16"'-lS'" dbh 30' rootwods 4 12"'-lS" dbh 30' .aotwo<b 16 totol 76 totol May Creek Stream and Wetland Enhancement Planting Plan - west of 148th Ave SE Latin Name Common Name SlzelSpeclflcatlons Quantity Emergents .. for alcoves near stream ----c-.m. ,." (I'l1:01 IT O.c.) ~ --~IpilH1lS~ Pac (PII:IIlZ"O.Cj "" C."...,¥/ipIlta Sawbeak ed&e Plus (P'Wl1 Ir O.c.) so, ShrubslWlllows 24w Heiibl, II· Root Spread Red-oiscJ dogwood. M'mimum .. tori .. ,] livc buds o",,/U fri:az Plant]' D,C. '" 2." Hcjpl, 11" lttIoJI Spla4 PhysaOJrpllS capWtuJ MinImz>m 4 IWias. 3 li~e bwh .... ,,-.. PI>Io!J'Oc. "" 24" Height,ll" Root SJ::n:ad Roup4ocGrptI. SWartlPrOK Minimum" twias.lliYC buds Plant]' O.C '" 2.· Hd&ht, II" Root Spread $pif"Qft d~lClas:ii DoualasSpire:a Minimum .. nrip,l live b.od! Plant)' O,c. '" 24" Helaht,ll" Root Spread RlllHu Jl'"lablfl$ ,_ Minimum 4 rwip. ] live bIIds Plant l' O.C. ,SO LiwSWtc, Minimum 6O"-7r Lm,3i4-1" D1~ M'1IIim=I 6 liR buds &JJ/zlasitmtJ", f'Kific wiUow Plant 2' a.c. ,~OO LiveSWcs Minimum 60" -72" Lone: 3/4-\" Di2lMlef . Minimum Ii live buds StJliz .cpuJ"i4ttQ ScouIer'. ""mow PlaDt2'O.C. ,~ lJ.oe pole Qll!lna Mirlimum7r_96R ~ Slllix Imllmthv PKitk willow Minimum r .)R diameter ''''''' Uve pole euttmg Mirlimum12R _96'" PopuJw Irld.O«lIpll Btacie Cmlonwood Minimum 2· .)~ diamccer 1,000 King County URPOSE: REDUCE DURATION OF flOODING PROJECT TITLE: ROPOSED WORK: ON PROPERTIES ADJACENT TO MAY CREEK: MAY CREEK DRAINAGE IMPROVEMENT REMOVE flOW OBSTRUCTING BETWEEN APPROX. RIVER MILE 4.3 AND .4.9. VEGETATION AND SEDIMENT FROM ClIRECTIONS TO SITE: SHEET TITLE: MAY CREEK. PLANT 15' BUFFER OF FROM COAL CREEK PARKWAY. (EAST OF LOG AND PLANTING TABLES NATIVE VEGETATION ON BOTH SIDES 1-405) TURN EAST ON S.E. MAY VALLEY OF CHANNEL. ENHANCE ROAD. GO TO 148TH AVE S.E .• TURN SOUTH OFF -CHANNEL WETLAND FISH TO BRIDGE OVER MAY CREEK. HABITAT DOWNSTREAM OF 148TH AVE DATUM: AS STATED SCALE: NOT TO SCALE S.E. N\\l\-)olo-I~ ASSISTANCE BY: LINDSEY MILLER SHEET: 8 OF 8 DRAWN BY: MEREDITH RADELLA DATE: AUG 13 •. 2010 --.-.------'-------------~ Jean Rollins 2905 Ilwaco Ave NE Renton, WA 98059 October 4, 20 II Mr. Phil Olbrecht Renton Hearing Examiner City of Renton 1055 South Grady way Renton, W A 98057 EXHIBIT 2S Re: May Creek Dredging Project-LUAII-065, V-H, SP Dear Mr. Olbrecht: Citations from scientific experts demonstrate that 9 of the 10 variance criteria to be used in the decision have not been met. Scientific statements in the record clearly provide there is an absence of valid scientific information and incomplete scientific information. Thls invalid and incomplete scientific information regarding the critical area of May Creek and its associated wetlands requires the Hearing Examiner take a "precautionary or a no-risk approach". (Renton Municipal Code 49-250 F.) Therefore, due to criteria not being met (90ut of 10) and invalid scientific information, we respectfully ask the Hearing Examiner deny the special permits. The following 5 documents will be referenced using the abbreviations in parentheses: Letter from Muckleshoot Indian Tribe Fisheries Division to Washington Department of Ecology dated May 11, 2011 (MITFD 5-11) Memo from Dr. Patricia Olson, Senior Hydrogeologist to Rebekah Padgett Washington Department of Ecology dated August 15, 2011 (Olson) Letter from Rebekah Padgett, Washington Department of Ecology to Doug Chin, WLRD(King County Water and Land Resources Division) dated Septemberl, 2011 (Ecology 9-1) Letter from Rebekah Padgett, Washington Department of Ecology to Doug Chin, WLRD (King County Water and Land Resources Division) dated September 22,2011. A copy is attached, as this letter is not in the record (Ecology 9-22) Letter from Muckleshoot Indian Tribe Fisheries Division to Washington Department of Ecology dated September 15,2011. A copy is attached, as this letter is not in the record (MITFD 9-11) 5bl. Public health & safety and welfare are not best served. Thls project is attempting to drain horse pastures at the detriment of family homes and sole access bridges. Dr. Olson, Senior Hydrogeologist a PHD with Ecology stated, " ... this hypothesis has not been tested using adequate data. Thls conclusion wouldn't be an issue if there were not structures downstream, but there are." (Olson Page 3) Experts stated in their denial letter that the county does not know what will happen downstream. -------------------------- . " ... outstanding issues remain ... sediment transport and data about what will happen downstream." (Ecology 9-22 Page 5) Staff states the hydraulic analysis shows the proposed project will not further contribute to ongoing erosion on properties downstream. However, experts state this hydraulic analysis is inappropriate: " ... for a study related to accessing potential hazards such as damage to structures (Olson Page 3) and "As pointed out in WLRD documents, HEC-RAS sediment transport model cannot address variable sediment transport conditions and changing channel elevations (erosion and deposition). Experts assert the County's conclusion that this project will not further .contribute to erosion is incorrect: "Since the sediment transport report and H&H study to rely on ... data that does not include adequate sampling points, I can not make a determination concerning potential for increased bank erosion downstream of the project area" (Olson Page 3) Dr. Olson goes on to say, "I disagree with the statement made in the H and H study that the increase in frequency of smaller floods is insignificant. The increase in frequency of these small floods could affect sediment transport dynamics." (Olson Page 3 -4) These unknown issues (erosion, increased frequency of flooding, sediment transport, sediment deposition and changing morphology of May Creek) jeopardize the health, safety and welfare of Renton residents downstream. 5b3. This project does not serve established indentified public needs. State and tribal experts reviewing this project are adamantly alarmed that this project will harm May Creek and its associated wetlands. Dr. Olson disagrees with many of the studies used and speaks to potential public harm downstream. "The studies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data." (Ecology 9-1 Page 5~ Muckleshoot Tribe's fish biologist has repeatedly warned adverse impacts could result. "As noted in all previous comments, MITFD is concerned that dredging May Creek will cause adverse impacts to salmon and their habitat. This project proposes to dredge 2,000 linear feet of May Creek and its associated wetlands in areas identified as salmon spawoing and rearing habitat (May Creek Baseline Stream Conditions Report)" (MITFD 5-11 Page 1) "The Impact Analysis and Mitigation report {(WLRD's} clearly states the project will adversely affect Essential Fish habitat for Coho." (MITFD 9-11 Page 1) "If the County is going to conduct dredging of May Creek to benefit existing livestock operations on private property then enforceable farm plans should be part of this project." (MITFD 9-11 Page 4) This project serves private properties not public needs. This project does not protect residential properties downstream; rather it places them in jeopardy! Harming downstream does not serve public needs neither does adverse impacts to May Creek nor its salmon rearing habitat. 5b4. Alternatives comparable in benefit to this project were not examined Practical alternatives such as bullet 4 in Renton's staff recommendation regarding farm management plans were not seriously considered. In their May 11, 2011 letter, the Muckleshoot Indian Tribe Fisheries Division listed potential alternatives on page 3. MlTFD even quotes the KC code that, "property owners are required to have a farm plan with maximum densities oflivestock." Further, " ... more effort of the obvious land use and pasture related sediment sources and allow the May Creek more room to store and transport its sediment load, consistent with natural stream processes." (MlTFD 5-11 Page 2) Muckleshoot Indian Tribe Fisheries Division requested the County " ... exhaust all less impacting alternatives prior to dredging May Creek ... (MITFD 9-11 Page 1) Dr. Olson's memo on page 2, suggests various options including a cost benefit analysis. Also on page 4, Dr. Olson states that King County should explore other options. The County used large projects as alternatives and justified this proposal by saying it was all the county could afford. The WLRD (King County Water and Land Resources Division) did not compare apples with apples. Those large scale alternative projects do not reduce flooding duration by a mere .04 %, as this project will do. The benefit of this proposal is very small. Other alternatives comparable in benefit were not examined. For example, farm management plans and critter pads. Alternatives comparable in benefit have been ignored. Given the minimal benefit of the proposal and the enormous cost of mitigation: what about the alternative of no action at all? Eighty percent of a 3.7S-acre wetland will have to be disturbed. Why not consider taking no action and save taxpayers dollars? SbS. The proposed action DOES NOT TAKE afflrmative and appropriate measures to minimize and compensate (or unavoidable impacts. The scientists at Ecology purport the models used do not adequately address erosion or deposition and hence WLRD does not know what will happen downstream: " ... outstanding issues remain including buffer, baseline data, sediment transport and data about what will happen downstream" (Ecology 9-22 Page 5) Dr. Olson disputes the erosion thresholds, and sediment transport numbers. Dr. Olson laments the lack of accurate studies as to where sediment volumes will be transported, downstream sediment deposition, an upstream sediment report, geomorphic analysis and an erosion report. On erosion thresholds she states, "This bias ... resulting in higher discharge to mobilize bedload." "The lower end of the range (73-150 cfs) estimated in the H and H study appears more realistic for the areas we observed." She continues, "As pointed out in {WLRD} documents, HEC-RAS sediment transport model cannot address variable sediment transport conditions and changing channel elevations (erosion and deposition)." Further, since the sediment transport report and H&H study rely on " ... data that does not include adequate sampling points, I can not make a determination concerning potential for increased bank erosion downstream of the project area." (Olson Page 3) Please review Olson page 3 & 4 under downstream bank erosion and geomorphic analysis. She disagrees with the insignificance of smaller floods to downstream areas. She disagrees with the sediment transport numbers. She states King County's expertise should be consulted on this project. --------------- Dr. Olson ends her in-depth discussion of bank erosion, " ... the existing transport modeling should have independent review .... " (Olson Page 4) lbis means WLRD needs to go outside their organization to have the modeling reviewed. Incorrect baseline data, disputed sediment transport study, the lack of a sediment deposition study and appropriate erosion study all strongly indicate WLRD does not know what will happen downstream. "The studies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data. (Ecology 9-1 Page 5) "Outstanding issues remain ... data about what will happen downstream" (Ecology 9-22 Page 5) "King County should utilize its geologic and geomorphic expertise and further evaluate adding sampling points and designing an appropriate sediment transport and erosion study." (Ecology 9- 22 Page 5) It is inconceivable after so much input by scientists that the County does not have the necessary appropriate sediment transport and erosion studies. Since baseline data, sediment studies and erosion studies are inadequate or incorrect and downstream impacts are unknown, appropriate measures to minimize and compensate for unavoidable impacts is not possible. 5b6. Loss of value and function of Mav Creek & its wetlands The scientific experts indicate there will be function and value loss of both regulated May Creek and associated wetlands: " ... adversely affect May Creek, its associated wetiands."(MITFD 5-11 Page 2) " ... the extent of these mitigation measures is insufficient to mitigate for the permanent loss of 59,800 square feet of instream and overhanging habitat/vegetation as a result of this dredging project. "Additional mitigation is needed to fully mitigate for the unavoidable environmental impacts from this project. (MITFD 9-15 Page 1) "There appears to be a disconnection in the conclusions supporting dredging. A 5-16% increase in stream power for potential sediment transport events is not significant but a .04% decrease in flooding duration of 50cfs is significant enough to dredge. (Olson Page 4) Dr. Olson is stating she believes erosion could be increased by up to 15%. lbis potential increase is without appropriate erosion, sediment transport (both upstream and downstream) and sediment deposition studies. The potential increase could be much higher based on appropriate and correct studies, which do not exist. This is why Ecology stated WLRD is lacking, "data about what will happen downstream." The whole range of appropriate and correct data about what will happen downstream has not been gathered, and thus WLRD has produced flawed conclusions. ''The stUdies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data." (Ecology 9-1 Page 5) "The Hydraulic and Hydrologic Analysis report suggests that the decrease in flood durations at 100 CFS is 7 hours which suggests little benefit for substantial environmental impacts to May Creek." (MITFD 5-11 Page 4) "The King County documents indicate that flood storage will be reduced in the project area, so additional flood storage to compensate for that loss should be included in the project." (Olson Page 4). 'The Long Marsh Creek mitigation project is not mitigation. Further" ... is not a restoration project but more of a drainage efficiency project. .. " (Olson Page 2& 3) "These alcoves are proposed as mitigation for lost instream fish habitat. If they fill in during high flows, then their mitigation value will be lost or substantially reduced. (MITFD 9-11 Page 4) Mitigation proposed to compensate for loss function and value of both regulated May Creek and associated wetlands is not mitigation as declared by experts. Compensatory flood storage is not provided. For little benefit, a .04% decrease in flood duration versus substantial increases in erosion, stream value and function of May Creek and its wetlands will be lost. 5b7. Fish species are jeopardized Fish biologist in their submitted comments to the City of Renton avows various .fish species will be jeopardized : "This project proposes to directly impact the natural process of sedimentation and floodwater storage along May Creek without adequately assessing the potential impacts to salmon and their habitat in the project area and in upstream and downstream areas." "There is no estimate given for the potential loss of rearing habitat" (MITFD 5-11 Page 1 & 4 ) "Salmon watchers program indicate that adult Chinook, sockeye and Coho were reported as far upstream as Greene's Creek ... " (MITFD 5-11 Page 4) Greene's Creek is home to endangered, threatened or sensitive fish species. Greene's Creek is downstream in an area that Ecology says WLRD does not know what will happen if this project is permitted to proceed. Without quantifying the potential pre-and post project rearing habitat available for juvenile salmon in May Creek, it is not known which fish ( endangered, threatened or sensitive) utilize downstream rearing areas which may be negatively impacted by this project. Unknown loss of rearing habitat means the fish species are injeopardy. 5bS. Water QualitvDegradation Ecology denied WLRD the 401 certificate since WLRD did not demonstrate with reasonable assurance that water quality standards for surface water of the State of Washington will be met. (Ecology 9-22 Page 2) " ... outstanding issues remain including buffer, baseline data, sediment transport and data about what will happen downstream" (Ecology 9-22 Page 5) Baseline data, sediment transport, upstream sediment report (not done) and what will happen downstream {erosion, deposition, downstream channel response, sediment transport dynamics} were all found lacking by Ecology. These flaws in this project could negatively affect the surface water quality of May Creek. Further, impacts to groundwater including the wells in the downstream areas of May Creek have not even been addressed. 5b9. This poject requires more than a minimum variance (or an unlikelv desired purpose Throughout this whole process, the effectiveness of this project has been strongly questioned. The Army Corp of Engineers and Ecology has repeatedly stated and written that they question the very need and purpose of the project. The desired purpose being met is unlikely and oflittle benefit as expressed by the reviewing scientists: " ... one time dredging will not solve the flooding extent and duration over time. LiDAR data indicate that there are large floodplain areas below the channel elevation." "These conditions suggest that dredging is somewhat akin to trying to channelize a bathtub where water inflow is greater than water outflow." (Olson, Page 1) Ecology reaffirms Dr. Olson's input " ... Ecology believes the effectiveness of the proposed action for the stated intent of decreasing the duration of surface water on the grazed wetlands: Has not been fully demonstrated to merit the level of impacts proposed for .04% decrease in flooding duration 0[50 cfs and ... no upstream sediment study has been provided ... ," (Ecology 9-1 Page 4) Even as late as the denial letter on 9-22 Ecology required, "Reassessment and redesign of the project to address its effectiveness ... " (Ecology 9-22 Page 2) Avoidance of adverse impacts has not been accomplished by this project. The scientific experts repeatedly assert that the project is lacking necessary studies. They maintain the studies that are available are inappropriate, incorrect, or insufficient. Compensatory flood storage is not provided. Therefore, the adverse impacts of this project are not known. These flaws make it highly unlikely this project is avoiding significant adverse impacts to critical areas. The MITFD continue to stress the extent of these mitigation measures is insufficient to mitigate for the permanent loss of 59,800 square feet of instream and overhanging habitat/vegetation. Ecology believes this project does not merit the level of impacts proposed. SblO. Lack of Best Available Science. The scientific information used in the baseline data; stream transport, downstream erosion and modeling have been invalidated by state scientific authorities: "WLRD has well qualified fluvial geomorphologists and geologists on staff; however, it does not appear they were consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomorphic processes that create the current conditions, the downstream channel response including migration to changes in flow and sediment regimes." (Ecology 9-1 Page 5) The Long Marsh Creek Mitigation plan is not a mitigation plan according to Dr. Olson. 'The Long Marsh Creek mitigation project is not mitigation." (Olson Page 2) The mitigation for dredging including the alcoves according to the MITFD is insufficient. "These alcoves are proposed as mitigation for lost instream fish habitat. If they fill in during high flows, then their mitigation value will be lost or substantially reduced. (MITFD 9-11 Page 4) Compensatory flood storage is not provided. "The King County documents indicate that flood storage will be reduced in the project area, so additional flood storage to compensate for that loss should be included in the project." (Olson Page 4) "No upstream sediment study has been provided ... ," (Ecology 9-1 Page 4) "The project is re-dredging portions of May Creek dredged last in 2002 "with no data collected afterwards. (MITFD 9-15 Page 4) It is not Best Available Science to subject a creek to dredging and not monitor the effects. The lack of the use ofWLRD expertise to design this project is alarming to Ecology. Scientists have purported that best available science has not been used to design, understand, or mitigate this proposal. Conclusion 1bis project embodies alarming scientific issues and flawed conclusions based on inappropriate, insufficient, incorrect data and information. Ecology has upheld their serious scientific issues with denial of the 401 certificate. Ecology clearly substantiates that WLRD does not know what will happen downstream. For little benefit, a .04% decrease in flood duration; verses substantial increases in erosion, stream value and function of May Creek and its wetlands will be lost. 1bis project's potential detriment to downstream, May Creek and its wetlands far outweighs the private property benefit. These are not my conclusions, rather the conclusions of expert scientists, such as a PhD Hydrogeologist, fish biologist and wetlands biologist. Downstream of this project are homes and bridges in Renton. We citizens are faced with negative impacts involving safety, erosion and flooding. The reviewing scientists have validated all of our fears and more. Citations from scientific experts reflect that 9 of the 10 variance criteria in Renton's code have not been met. Experts' statements reveal this activity would be unreasonably detrimental to the surrounding area. Scientific statements in the record clearly provide there is an absence of valid scientific information and incomplete scientific information. 1bis invalid and incomplete scientific information regarding the critical area of May Creek and its associated wetlands requires the Hearing Examiner take a "precautionary or a no-risk approach". Therefore, we respectfully request the Hearing Examiner not grant a variance or special permit. Thank you for your thoughtful consideration in this manner, l.{.a.1'\.. 2~ J~Rollins Enclosures: Letter from Muckleshoot Indian Tribe Fisheries Division to Washington Department of Ecology dated September 15, 2011 Letter from Rebekah Padgett, Washington Department of Ecology to Doug Chin, WLRD dated September 22, 2011 MUCKLESHOOT INDIAN TRIBE Fisheries Division 39015 -172nd Avenue SE. Auburn, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 September 15,2011 Washington Department of Ecology-SEA Program Federal Project Coordinator P.O. Box 47600 Olympia, WA 98504 RE: May Creek Drainage Improvement Project, revised project, 401c and CZM Consistency Public Notice of Application Dear Sir or Madame: r". The Muckleshoot'Indian Tribe Fisheries Division (MITFD) has reviewed the Public Notice of Application for a State of Washington 401 Water Quality Certification and Coastal Zone Management Act Consistency for the May Creek Drainage Improvement Project This project is the first of potentially four phases to dredge May Creek in May Valley. In this first phase, the project proposes to dredge May Creek from River Mile 43 to River Mile 4.9, removing sediments, reed canarygrass, and some of the existing willows that are Within and adjacent to May Creek. As noted in all previous comments, MITFD is concerned that dredging May Creek will cause adverse impacts to salmon and their habitats. The Impact Analysis and Mitigation report clearly concludes that this project will adversely affect Essential Fish Habitat for coho. In addition, this is the first of potentially four dredging projects that would result in the dredging of2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May' Creek's entire length. The combined impact of all of these dredging projects would likely result in a significant loss of existing salmon habitat, and potentially future adverse impacts upstream and downstream from the dredged reaches as other landowners seek to protect their properties from bank erosion or sediment deposition and flooding. Again, we recommend that King County implement and exhaust all less impacting alternatives prior to dredging May Creek discussed further in the attached comments. While the proposal to fence and plant native wetland! riparian vegetation and create alcoves with wood and sediment is an improvement over the existing· conditions for most of the project area, the extent of these mitigation measures is insufficient to mitigate for the permanent loss of 59,800 square feet of ·instream and overhanging habitat! vegetation as a result of this dredging project. The proposed 15' planting buffer on both sides of May Creek, including the mitigation site that is an open space tract, is significantly leSs than Renton or King County's regulated buffers and will be insufficient to provide the Muckleshoot Indian Tribe Fisheries Division Comments to May Creek dredging Public Notice for 401c and CZM September 15, 2011 Page 2 full suite of riparian functions. Additional mitigation for this project is needed to fully mitigate for the unavoidable environmental impacts from the project. We remain concerned that this project is a "short term fix" and that there is a high likelihood that additional dredging will be proposed here and elsewhere in May Valley that may again adversely affect May Creek, its associated wetlands, and potentially the mitigation implemented for this project. Instead we recommend focusing more effort on the obvious land use and pasture-related sediment sources and to aJiow May Creek more room to store and lIansport its sediment load, consistent with natural stream processes. Additional specific comments and questions about this project are attached for your review and consideration. Please let me YJlOW if you have any questions al253-876-3 i 16. Sincereiy, , ;1 \ :.'V._/~ Y' .. Karen Walter Wakrsheds and Land Use Team Leader Cc: Lori Lull, USACOE Randy McIntosh, NMFS Larry Fisher, WDFW Region 4 Rebekah Padgett, WDOE, NW Region Patrick McGranger, WDOE, NW Region Dave Garland, WDOE, NW Region Jennifer Henning, City of Renton Planning Doug Chin, King County DNRP Jamie Hartley, King County DDES ..--------------- Muckleshoot Indian Tribe Fisheries Division Comments to May Creek dredging Public Notice for 401c and CZM May Creek 40 I (c) and CZM comments ---------- September 15, 2011 Page 3 1. We agree with the WDFW's issued HP A pennit condition that requires rounded boulders, cobbles, and gravel proposed to protect the outlet of Long Marsh Creek instead of the quarry spalls riprap shown on Sheet 4 of the July 20, 201 I drawings and Sheet C2 of the 70% Design Plans. A new project drawing should be submitted to reflect these changes. 2. Any tree equal to or greater than 4 inches diameter (DBH) and removed from within 200 feet of Long Marsh Creek or May Creek should be placed back into Long Marsh Creek or May Creek downstream of 14Sth Ave SE to partially mitigate for the temporal impacts from their removal. The 1-npact Analysis and Mitigation Plan states that sixteen trees over 6 inches DBH will be removed along Long Marsh Creek (page 16). Tnere may be more once May Creek is considered. 3. The 200 I May Creek Basin Plan Appendix H an?Jyzed dredging in some detail and made several conclusions: • A dredged channel of 1.5 feet in depth and 11 feet in width with a planted 61 foot wide floodplain bench would need to be dredged and replanted every 20 years at an estimated maintenance cost of2.8 million dollars from 2001 estimates; • Increasing the stream gradient to minimize sediment deposition and maintenance would require dredging 9 to 32 feet; • Dredging would compromise the bridges at 14Sth Ave SE and I 64th Ave SE and their replacement was identified as a necessary element of any dredging project; • If a dredging project moves water more quickly out of May Valley, then peak flows in the downstream reaches of May Creek would significantly aggravating an existing erosion problem in May Creek canyon, thus requiring detention ponds that would cover 23 acres or 113 ofthe existing May Valley eliminating riparian and wetland habitat; and • Appendix H also noted that dredging May Creek would likely drain 100 of the estimated 142 acres of May Creek Wetland 5. It is not apparent that much has changed since King County completed the Final 200 I May Creek Basin Plan leading to the conclusions above including additional information in the 200S May Creek Drainage and Restoration Plan. For example neither bridge is proposed to be replaced. King County should discuss each of these bulleted items and explain in detail what has changed or what new analysis exists to refute these earlier conclusions. 4.· Of the alternatives identified in King County's responses to the previous MITFD 40lc comments (letter dated May 11 2011), additional information a..'1d a..'1alysis should be provided to support the Muckleshoot Indian Tribe Fisheries Division Comments to May Creek dredging Public Notice for 401 c and CZM September 15, 2011 Page" statement that the "implementation of farm management plans, including construction of farm pads would have more long-term adverse impact on critical areas", including instream habitat for salmon than dredging May Creek here and at the future sites upstream. 5. King County has code authority to require farm management plans under 21A.30.070 (see King County's responses to MITFD 401c comments). If the County is going to conduct dredging of May Creek to benefit existing livestock operations on private property, then enforceable farm plans should be part of this project. 6. We request a copy of the survey data from the Long Marsh and May Creek sediment removal projects (see King County's responses to MITFD 401c comments). 7. More wood should be added to Long Marsh Creek to provide sediment storage, including channel spanning logs to meter sediment transport and deposition. 8. The McFarlandiGambini footbridge needs further analysis to demonstrate that it is not causing a backwater effect and allowing gravel to deposit into May Creek causing one identified obstruction. If the bridge is causing a backwater effect, then the new 100 foot side channel and channel meandering in Long Marsh Creek will not resolve this problem and sediment deposition at the confluence will continue. Instead, the footbridge should be modified to accommodate the gravel load or removed during overbank flooding to allow sediment movement in May Creek. 9. In King County's 2010 responses to the 1I1ITFD and WDOE SEPA comments, the County suggests that the proposed mitigation alcoves downstream of 148th Ave SE will allow sediment to deposit outside of the main channel at higher flows. These alcoves arc proposed as mitigation for lost instream fish habitat. If they fi1J in during higher flows, then their mitigation value will be lost or substantially reduced. Additional analysis is needed to demonstrate that these alcoves will not fill in and if so, what additional mitigation will be provided. 10. The plan sheets (Sheet 14 of70% design) show only a portion of the existing open space tract west of 148 th Avenue SE being enhanced. Additional mitigation needed to meet the "no net loss" standard for wetland and strealn impacts could occur here, including expanding the wetland mitigation area and enhancing Green Creek that flows into the mitigation site. 11. The project is re-dredging portions of May Creek dredged last in 2002. Unfortunately, no data was collected regarding effects on salmon, flooding and sediment accumulation, nor were as-built drawings prepared (see King County's response to MITFD dated December 22, 2010). All we know is that whatever work completed in 2002 was not sufficient to avoid dredging 10 years later. We are concerned that the project will not function as designed requiring more frequent dredging than modeled. At a minimum, the Construction Water Quality Protection and Monitoring Plan needs to be modified as follows: Muckleshool Indian Tribe Fisheries Division C":nmmAnt. to Mav Creek dredaina Public Notice for 401 c and CZM September 15, 2011 PageS • Monitor sediment accumulation and erosion in May Creek, including downstream in the M~v Creek ravine: • Collect data to document changes in channel cross-sections and longitudinal profiles; and • Collect data to document that the flood frequency durations were reduced as predicted, • The project should also monitor for adult and juvenile salmon use this year and post con<t1'llctjon. • Any project deficiencies should be addressed through an enforceable contingency plan. 12, We request a copy of the Draft Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report that was referenced but not included with King County's responses to our May II 2011 comments, 13, We are still very concerned that the I S foot mitigation riparian vegetation buffer will not provide the sillte of riparian functions needed to create and maintain salmon habitat. As I S foot riparian buffer is also inconsistent with KCC 2IAJO.04S.B and the farm plans that exist for 2 of the project's properties, A minimum 2S foot buffer on all properties benefiting from this project should be provided as a partial "out of kind" mitigation measure for this project's adverse impacts to salmon habitat documented in the Stream and Wetland Impact Analysis and Mitigation Plan (KC 2011). The open space property downstream of 148th Avenue SE should have a riparian buffer of at least 100 feet as required by the City of Renton's Critical Areas code, STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional DjJictJ 3190 160th SE Bellevue. Washinglo1l98008-5452 (425) 649-7000 September 22, 2011 Doug Chin, Project Manager King County Water and, Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 RE: Ecology Denial for Section 401 Water Quality Certification for the May Creek Drainage Improvement Project, Renton, King County, Washington Dear Mr. Chin: The U.S. Anny Corps of Engineers (Corps) issued a joint public notice with the Washington State Department of Ecology (Ecology) for the above project on September 24,2010. Ecology has one year to issue an individual Section 401 Water Quality Certification (401 Certification). On August 31, 2010, Ecology notified you by celtified letter that this project would require a 401 Certification. On April 21, 2011 and September I, 2011, Ecology issued additional public notices regarding King County's two revised applications for 401 Certification. We detennined that your application for an individual 401 Celtification was incomplete and sent you a certified letter on September 1, 2.0 II detailing the specific information that was needed to complete your application and stating that if Ecology did not receive all of the required documentation by September 16,2011, Ecology would deny the 401 Certification for this project. In our September 1, 20 II letter we identified the following infonnation needed in order to complete our review: • A description' of how sediment disposal areas will be stabilized. • A Construction Water Quality Protection and Monitoring Plan. • Measures to be taken regarding stream water temperature changes between removal of mature vegetation and when replanted vegetation reaches the size to shade the creek. • Revisions to the Mitigation Plan. • Revisions to the sediment monitoring plan. • Site plan revisions. . • Details on the Long Marsh Creek riparian planting buffer. • A copy of the Final Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report. • . Expanded riparian vegetation buffers. • Study of the resizing or removal of the 1481h Avenue SE Bridge. King County Water and Land Resources Division' September 22, 20 II Page 2 • Reassessment and redesign of the project to address its effectiveness, including further evaluation and study of sediment transport and downstream erosion, as well as independent review of sediment transport modeling. On September 16, 2011, Ecology received a response addressing some of the information requested. Unfortunately we have not rec.eived all of the documentation needed in order to demonstrate that we have reasonable assurance that state water quality standards will be met:«We have attached a project chronology that details that we have been trying to work with you to get the needed information in order to process your request for a 401 Certification.· Pursuant to Section 401 of the Clean Water Act. ch. 90.48 RCW and ch. 173-201A WAC, the May Creek Drainage Improvement Project water quality certification is denied without prejudice. Receipt of a denial without prejudice does not preclude King County Water and Land Resources Division from reSUbmitting a request for 401 Certification at a later date. t'[QlTI~t§!!i'OO\'._~~~~~~~~ You have a right to appeal this Order to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this Order. The appeal process is governed by Chapter 43.21B RCW and Chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.00I(2). To appeal you must do the following within 30 days of the date of receipt of this Order: • File your appeal and a copy of this Order with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. • Serve a copy of your appeal and this Order on Ecology in paper form -by mail or in person. (See addresses below.) E-mail is not accepted. You must also comply with other applicable requirements in Chapter 43.21B RCW and Chapter 371-08 WAC. Department of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, W A 98503 Pollution Control Hearings Board 1111 Israel RdSW STE 301 Tumwater, WA 98501 Department ofEeology Attn: Appeals Processing Desk PO Box 47608 Olympia, W A 98504-7608 Pollution Control Hearings Board PO Box 40903 Olympia, W A" 98504.0903 King County Water and Land Resources Division September 22, 2011 Page 3 . Please direct all questions about this Order to: Rebekah Padgett Department of Ecology Northwest Regional Office 3190 1 60th Avenue SE Bellevue, W A 98008 (425) 649-7129 Rebekah.Padgett@ecy.wa.gov liIliiE>°E;~E~Ii'Qi''''Sm'I~''~-3~~;;g;:i;;~~~~~~~#~ ~!!,.~.,_,~~~IIJ, .. '..i,~ ._-,;: -.: __ ~ ."..,;:'::';. :~~'P-'--===-=",",:~..::..-r:.-g:::s:=-~~~'='~S-=--:;'*~= . ~ Pollution Control Hearings Board Website www.eho.wa.govlBoards PCHB.aspx Chapter 43.21B RCW -Environmental Hearings Office -Pollution Control Hearings Board http://apps.leg.wa.govIRCW/default.aspx?cite=43.21B Chapter 371-08 WAC -Practice and Procedure http://apps.leg.wa.govIWAC/default.aspx?cite=371-08 Chapter 90.48 RCW -Water Pollution Control http://apps.leg.wa.govIRCW/default.aspx?cite=90.48 Chapter 173-201A WAC -Water Quality Standards for Sunace Waters of the State of Washington www.ecy.wa.govlbiblio/wacI73201A.html Erik Stockdale, Unit Supervisor Wetlandsl401 Unit Shore1ands and Environmental Assistance Program Northwest Regional Office ES:rrp:cja Enclosure By certified mail 7011 0470000337209107 September 22, 20 II King County Water and Land Resources Division September 22, 20 II Page 4 cc: Lori Lull, U.S. Anny Corps of Engineers TJ Stetz, U.S. Anny Corps of Engineers Larry Fisher, Washington Department ofFish and Wildlife Karen Walter, Muckleshoot Indian Tribe Katie Bonwell e-cc: Patrick McGraner -NWRO Patricia Olson -HQ Loree' Randall-HQ Raman Iyer -NWRO ecvrefedpennits@ecy.wa.gov Jennifer Henning, City of Renton Jhenning@Rentonwa.gov Jean Rollins urbanseparator@hotrnail.com Debra Rogers herogers@comcast.net Susan Malin susiemalin@msn.com Gal)' Amundson garv.a@comcast.net Andrew Duffus klassicars@hotmail.com Carol Tabacek caroltabacek@aol.com Mary Weirich maryyweirich@comcast.net A. Duffus blueheron6987@hoimai1.com Julie & Jim Bonwell ibonwell@lesourd.com 1126/10 2122110 3124/10 5/5110 5/13/10 6124/10 Attachment 1: May Creek WQC Permitting Chronology Ecology attended an interagency meeting organized by King County with discussion about the 'potential to create a multi-agency permitting team, A brief introduction and overview of the project concept at this early stage was presented. The U.S. Army Corps of Engineers (Corps), Ecology, Washington Department of Fish and Wildlife (WDFW), Muckleshoot Indian Tribe, Governor's Office of Regulatory Assistance, and King County representatives wet'e present. Ecology attended a field meeting with King County, WDFW, and the Muckleshoot Indian Tribe. Ecology staff raised concerns about the effectiveness, purpose and need of the proposed project. Specific comments included: the effectiveness of the IS-foot-wide buffers, concerns about direct animal access to stream, severely degraded pastures and the need for farm plans, extent of the wetland and primary sources of hydrology, and concerns about establishing woody vegetation in very wet soils. Ecology observed that livestock have direct access on one of the project properties upstream of the project area Ecology provided written comments via e-mail that followed up on the 21221\ 0 site visit. Ecology participated in an interagency pre-application meeting and provided substantive comments regarding the effectiveness, purpose, and need of the project, as well as the need to redelineate the wetland; buffer width, and limit livestock access to the creek. Ecology raised concerns about 303( d) listing for, fecal coliform and the preference for 35-foot buffers and wider planting on the south side buffer to reduce summer temperatures through shading. Ecology questioned the 2002 pilot described by King County where two sediment plugs were removed from side chanoels on the McFarland property, specifically whether it would be comparable to the current proposal and what post- construction monitoring was completed. Ecology raised the question of whether the proposed one-time dredging would accomplish the goals of the proposal; the COlmty indicated that it was planning a series of projects, working from this site upstream. Ecology also pointed out that the baseline stream report included language that contradicted and would not support this proposal. Downstream erosion concerns were discussed, and King County staff noted that they had conducted modeling and did not believe that the sediment removal would increase erosion downstream. King County submitted the Joint Aquatic Resources Permit Application (JARP A) package to Ecology. The Corps canceled the application. Ecology canceled the 401 application based on the Corps' 5/13/1 0 a~tion. King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment 1 September 22, 2011 Page 2 8/16/10 9/8110 9/16/10 9/20/10 9/22/10 9124110 10110 10/23110 12/16/10 313/11 3/18111 King County submitted a revised JARP A to Ecology. King County submitted a Certification of Consistency with the Washington State Coastal Zone Management (CZM) Program to Ecology. Ecology submitted comments on the State Environmental Policy Act mitigated determination of non-significance (MDNS) regarding effectiveness, purpose, and need of the proposal, buffer width, how wet the left bank is in Reach 4 for establishing canopy cover, the degradation of the pastures and need for farm plans to protect riparian habitat and creeks, and livestock access to the creek. Ecology received substantive public comments from downstream residents. Issues raised included concerns about increased erosion, sediment transport thresholds, cumulative impacts, and the need for additional detailed study of the potential downstream impacts. Ecology received substantive public comments from the Muckleshoot Indian Tribe raising concerns about net loss of habitat, downstream erosion, insufficient buffers and the probability that the proposed dredging will be a sholt-term fix. Corps issued a joint public notice with Ecology. Ecology received substantive public comments from downstream residents. Issues raised included concerns about the purpose and need of the project, draining of wetlands, water quality, salmon habitat, increased flow, and bank erosion, as well as questions about the 2002 pilot. Ecology received substantive public comments from the City of Renton that included concern about effects of increased velocity, flow, or erosion on downstream properties. Ecology received King County's responses to Ecology MDNS comments. In the response letter, the County defends the proposed 15-foot buffer not as best available science (BAS) but as an improvement over existing conditions citing property owners' reluctance to expand planting areas, states that it calUlot require farm plans from private property 0'<':!lerl\0r require owners ,vith farm plans to implement them properly, and notes tliat the planting areas will be fenced and will therefore effectively eliminate livestock access to the creek. Ecology and King County jointly extended the CZM review period until 9/8/11. King County submitted another revised JARPA to Ecology. This revision included new impacts to Long Marsh Creek that the County referred to as miti,jfation, therefore reducing proposed mitigation downstream of 148 Avenue SE. - ----~~~~~~~~~~~~~~~---- King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment 1 September 22, 2011 Page 3 4/5/11 4/21/11 4/26/11 4/28/11 5/11 5/11/11 Ecology received substantive public comments from the Neighbors for 1\1[ay Valley, who raised concerns about stream flow velocity, volume and timing of storm events, floodiog and erosion. Downstream property owners requested that King County allow the project to be delayed at least one water year to establish a pre-project erosion baseline. The downstream citizens requested additional assurances that the proposed dredging will not have unintended negative consequences to downstream properties. Ecology issued a public notice on the revised application. Ecology participated in an interagency site visit where staff raised questions about the effectiveness, purpose, and need of the project, permanent protection ofthe mitigation area, the buffers on Long Marsh Creek, whether the Long Marsh Creek work was really mitigation, project-specific monitoring of sediments in the project area and downstream, best management practices, proposed buffer widths, how wet the left bank is in Reach 4, and the need for future dredging. Ecology followed up bye-mail documenting questions raised at the 4/26111 site visit. Ecology received substantive public comments from downstream property owners questioning assumptions being made by King County based on modeling within the Hydraulics and Hydrologic Analyses using limited data, expressing concerns about downstream erosion, increased turbidity, and the proposed IS-foot planting buffer as not meeting BAS or County code. Specific questions also were raised with regards to the adequacy of the information provided by King County that claimed that the 2002 pilot project along a 300-foot section of the creek upstream of the proposed project was successful, erosion thresholds, potential for shallow well contamination, flow velocity, volume and peak flow during storm events potentially risking sole-access bridges to properties, and the adequacy of the 15- foot planting buffer. Ecology received additional substantive comments from the Muckleshoot Indian Tribe emphasizing the need to improve pasture conditions and control other existing sediment sources through agricultural best management practices andlor farm plans, minimize the dredging area with increased mitigation for impacts, increase the proposed planted buffer width, provide additional riparian plantings, measures to avoid impacts to downstream reaches, mitigation for any unavoidable impact to downstream reaches, future dredging projects, and potential impacts to . salmonids. King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment I September 22, 2011 Page 4 6110/11 7/1111 7/8/11 7/19/11 7122111 Ecology received King County's responses to Ecology's 4126/11 and 4128/11 conunents. In its letter, King County stated that downstream impacts have been sufficiently analyzed and that a formal monitoring plan is not warranted; based on previous analysis and current design features, re-sedimentation monitoring is not warranted at this time; and there are no future plans to implement additional upstream sediment removal proj ecls. King County continued to defend the proposed 15-foot buffer as being adequate even within the very wet portion of the left bank in Reach 4. In response to ongoing concerns from Ecology regarding the effectiveness of the proposed project, King County again stated that the project is only designed to reduce overbank pasture flooding for a short period of time on each end of the rainy season and that monitoring wells have been installed to assess groundwater pre-and post-project. Ecology received King County's responses to a public comment in which the County restated that the 15-foot proposed planting buffer, while not based on BAS, is an improvement over existing conditions as demonstrated by the results of the 2002 pilot project upstream of the current proposal and that the continuous hydrologic watershed mode used accounted for all peaks, all durations and all . flow rates at all locations. King County reversed its position from 611 Dill and . agreed to conduct downstream monitoring for a period of 5 years post-project. Ecology responded to King County by requesting a copy of the downstream monitoring plan with note that the plan should be comprehensive and not simply address the issues raised by one property owner. Ecology received King County's responses to a public comment in which the County stated that downstream monitoring will be conducted for a period of 5 years and that if monitoring data collected clearly shows that erosion problems result from the project, that it will offer technical assistance and perform remediation. The County indicated that it has no future plans to implement additional sediment removal projects upstream of this project site. Ecology received King County's responses to a public comment stating that the project will not increase existing erosion problems downstream, proposing 5 years of downstream monitoring and working with the property owner on a solution if the monitoring shows downstream erosion resulting from this project. Ecology received King County's responses to the Muckleshoot Indian Tribe 5/11/11 comments. The e-mail states that the County does not have plans to implement the other three upstream dredging projects. In response to the tribe's comment that King County Code requires existing livestock operations to implement a farm management plan or meet management standards outlined in the Code, the County indicates that two ofthe four livestock operations have developed plans and that the buffers specified in these plans are 25 feet (10 feet more than the County is proposing through this project). The County also acknowledges t/lat the I 48th Avenue SE Bridge causes a backwater effect. King County Water and Land Resour"",! Division May Creek Drainage Improvement Project Attachment I September 22, 2011 PageS" 7/26/11 8/2/11 9/1/11 9/7/11 9/14/11 9/15/11 9/16/11 Ecology again visited the project site, including downstream properties. King County submitted another revised JARP A. The revision addresses Long Marsh Creek impacts and includes additional mitigation. Ecology sent a letter by Certified Mail to Doug Chin requesting additional information and stating that project 401 Celiification would be denied if the requested documentation was not received at Ecology by September 16, 2011. Ecology issued a public notice on the revised application. Ecology and lGng County jointly extended the CZM review period until 11/8/11. Ecology received a public comment from a property owner reiterating questions about the need for the project and concerns about downstream erosion and flooding impacts Ecology received public comments from a property owner reiterating concerns about downstream erosion and flooding impacts, raising the need for additional erosion monitoring and stream flow devices, and questioning the need for the project. The property owner raises questions about the stream and wetland buffer width, storm surge flows, hydraulic and hydrologic analysis, cumulative impacts, compensatory stormwater storage, and the need for additional data and analysis. Ecology received public comments from the Muckleshoot Indian Tribe reiterating concerns about salmonids and habitat, cumulative impacts, likely future dredging, insufficient buffer widths, and the adequacy of mitigation. The letter also notes the need to consider less-impacting alternatives, have enforceable farm plans in place, for further analysis on backwater effect of the McFar1andlGambini footbridge, to consider impacts of sediment deposition in the mitigation alcoves, for sediment accumulation and erosion monitoring, to collect data regarding changes in channel cross-sections and longitudinal profiles and data on flood frequency durations, to monitor for sa4nonid use, and for a contingency plan. Ecology received additional public comments reiterating concerns about downstream flooding and erosion. Ecology received King County's responses to the 911111 letter requesting additional information. While some questions were addressed, outstanding issues remain including: buffers, baseline data, and sediment transport and data about what will happen downstream. . I I I I I I I I I I I I I I I I I I I EXHIBIT 26 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project December 17, 2010 King County Department of Natural Resources and Parks Water and Land Resources Division Science section King Street Center, KSC-NR-0600 201 SOuth Jackson Street, Suite 600 Seattle. WA 98104 Alternate Formats Available 206-296-7380 TTY Relay: 711 CiW of Renton Planning DIVISion ",\Jb -5 lUl\ Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Prepared for: King C()unty Department of Natural Resources and Parks Stormwater Services Section, Capital Services Unit Prepared by: Jeff Burkey Hydrologist King County Water and Land Resources Division Department of Natural Resources and Parks ti King County Department of Natural Resources and Parks Water and Land Resources DIvIsion (206) 296-6519 I I I I I I • I I I ,. • I I • • I I • I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Citation King County. 2010. Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by.Jeff Burkey, King County Department of Natural Resources and Parks, Science Section. Prepared for Stormwater Services Section, Capital Services Unit. King County December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table of Contents Executive Summary ....................................................................................................................... vi 1.0. Introduction ......................................................................................................................... I 1.1 Study Goals ..................................................................................................................... I 1.2 Study Extent .................................................................................................................... I 2.0. Model System Design ......................................................................................................... 3 2.1 Objectives ....................................................................................................................... 3 2.2 System Overview ...................................................................................... : ..................... 3 2.3 HEC-RAS Model Setup ...................................... ; ........................................................... 3 2.3.1 Survey Data ................................................................................................................. 4 2.3.2 Flow Rate Change Locations ...................................................................................... 5 2.3.3 Channel Roughness ..................................................................................................... 6 2.4 Hydrology ....................................................................................................................... 7 2.4.1 Precipitation ................................................................................................................ 7 2.4.2 FT ABLES ................................................................................................................... 8 2.4.3 Refined Estimate of Stream Flow Events for Phase II Sediment Study ..................... 9 2.4.4 Model Validation ...................................................................................................... 15 3.0. Scenario Development ...................................................................................................... 25 3.1.1 Model Geometry ....................................................................................................... 25 3.1.2 Typical Channel Cross-Section ................................................................................. 28 4.0. Sediment Transport ........................................................................................................... 30 5.0. Results ............................................................................................................................... 31 5.1 Improved Channel Conveyance .................................................................................... 37 5.2 Updated Flow Frequencies ........................................................................................... 46 5.3 Reduced Duration of Flood Inundation for Smaller more Frequent Events ................. 52 5.4 Flow Rates Competent to Pass Silts through the System ............................................. 54 5.5 Durations of Flow Rates in the Ravine ......................................................................... 56 5.6 Other Considerations .................................................................................................... 57 6.0. References ......................................................................................................................... 58 Figures King County ii December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure I Locator map of study area in May Creek basin ................................................................ 2 Figure 2 Extent of January 20 I 0 King County Survey ................................................................... 4 Figure 3 Gauge monitoring locations ............................................................................................. 9 Figure 4 Flow rates for the December 2007 event.. ...................................................................... 10 Figure 5 Flow rates for the January 2009 event.. ........................................................................... II Figure 6 Stages for December 2007 event. Note the obvious data errors in station 37G ............. II Figure 7 Stages for January 2009 event. Note the missing data for 37G ..................................... 12 Figure 8 Robust Regression (LOWESS-Locally weighted scatter plot smoothing) on Daily Peak Flow Rates from 11/1/1998 through 2/5/2009. X-axis = 37A, Y-axis = 378. Lower graph is a simulation of 37B using the regression and observed with time on the x-axis, and flow rate on the y-axis ................................................................................................................... 13 Figure 9 December 2007 Hydrograph of event ............................................................................ 14 Figure 10 January 2009 Hydrograph of event .................................................................. : ........... 15 Figure II Edge of water survey shown in light blue lines ............................................................ 16 Figure 12 January 2010 Hydrograph for King County Gauge 37G (148th Bridge) ..................... 18 Figure 13 Profile of observed water surface elevations for January 8 (downstream of footbridge) & 22 (upstream of footbridge) with left and right bank elevations (LOB, ROB) plotted .... 19 . figure 14 Example of cross-section where water surface elevation is same elevation as bank elevation (RM 4.974). Obstruction in cross-section is representative of dense canary reed grass on the banks ................................................................................................................. 20 Figure 15 Example of overbank flooding slowly draining back into channel after a storm from 7 days prior (with some minor precipitation 4 days prior). Photo taken 3119/2010 ............... 21 Figure 16 Observed water surface elevation for January 14,2010 at 64 cfs at Parcel #0223059005 footbridge ....................................................................................................... 22 Figure 17 Observed water surface elevation for March 30, 2010 at 48 cfs at three bridges ........ 23 Figure 18 Scenario 7 longitudinal profile in study area. The black line is channel bottom using top of sediment (used in Scenario I) and fuschia color line is profile of channel bottom to firm sediment. ....................................................................................................................... 26 Figure 19 Scenario 8 showing existing conditions and proposed profile after sediment removal (308 ft) and flushing of silts .................................................................................................. 27 Figure 20 Scenario 9 showing existing conditions and proposed profile after sediment removal (309 ft) and flushing of silts .................................................................................................. 28 Figure 21 Typical Channel Geometry of existing (black line) and proposed (fuschia line) ......... 29 Figure 22 Guo-Shields Empirical Curve ....................................................................................... 30 Figure 23 Scenario I (existing conditions) water surface profile for mean annual (filled in water surface) and Conditions Report I year event (blue line with symbols) ................................ 31 King County iii December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure 24 Water surface profiles for the I-year (Conditions Report) for Scenario I and 8. Red circle highlights the convergence of profiles at 146th Ave bridge ....................................... 32 Figure 25 Water surface profiles at 50 cfs for Scenario I and Scenario 8 .................................... 33 Figure 26 Water surface profiles for the 100 year flood event for Scenario I and 8 .................... 34 Figure 27 Water surface elevations (Scenario I and 8) for the 100 year (Conditions Report) at the 146th Ave bridge ................................................................................................................... 35 Figure 28 Water surface elevations for the 100 year return period (Current Conditions) at bridge crQssing at I 43rd Avenue SE for Scenario I and 8 .............................................................. 36 Figure 29 Perspective plot for Scenario I (Existing Conditions) mean annual flow rate (8.6 cfs at 148th Street) .......................................................................................................................... 37 Figure 30 Longitudinal plot for Scenario I (Existing Conditions) water surface profile for mean annual flow rate ..................................................................................................................... 38 Figure 31 Perspective plot for Scenario I and 7 (vegetation removal).50 cfs at 148th Street. Light blue are for existing conditions while dark blue are for Scenario 7 ............................ 39 Figure 32 Water surface profile at 50 cfs for Scenario I and 7 .................................................... 40 Figure 33 Perspective plot comparing Scenario I and 7 under mean annual flow rates .............. 41 Figure 34 Perspective plot for Scenario I and 8 overbank flooding with 50 cfs at 148th Street. Light blue areas are inundated areas for Scenario I and dark blue are Scenario 8 ............... 42 Figure 35 Water surface profile at 50 cfs for Scenario I and 8 .................................................... 43 Figure 36 Water surface elevations for the 2 year return period (229 and 240 cfs) for Scenario I and 8 ...................................................................................................................................... 44 Figure 37 Perspective plot for Scenario I and 9 overbank flooding with 50 cfs at 148th Street. Dark blue areas are for Scenario 9, light blue are for Scenario I (existing conditions) ....... 45 Figure 38 Water surface profile at 50 cfs for Scenario I and 9 .................................................... 46 Figure 39 Flow Frequencies for existing conditions using USGS 17-8 methodology for flows at 148th Avenue SE (catchment MVL) .................................................................................... 49 Figure 40 Flow Frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) for flows drainging to 148th Aveneue SE ........................................................ 50 Figure 41 Flow Frequencies using USGS 17-8 methodology for existing conditions at Coal Creek Parkway (catchment CCP) ......................................................................................... 51 Figure 42 Flow frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) at Coal Creek Parkway (catchment CCP) ........................................................ 52 Tables Table I Stationing for structures in the HEC-RAS modeL ........................................................... 4 King County iv December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table 2 Example of Flow Change Locations in HEC-RAS for mean annual flow rate ................. 5 Table 3 Vertical varying roughness by flow rate ............................................................................ 6 Table 4 Monthly scalars to transpose SeaTac precipitation to May Valley ................................... 7 Table 5 Accuracy of robust regression for simulated versus observed for gauging station 378 using linear regression statistics, with observed on the x-axis for slope .............................. 14 Table 6 Water surface observations, elevations in NAVD88 .............................................. , ........ 16 Table 7 Summary of flood frequencies for Scenario 1 and Scenario 8 for May Creek in the valley ..................................................................................................................................... 47 Table 8 Summary of flood frequencies for Scenario 1 and Scenario 8 for May Creek in the ravine ..................................................................................................................................... 47 Table 9 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows passing through the project area (catchment MVL outlet at 148'h Avenue SE) based on HSPF simulation WY 1949 -WY 2008 .......................................................................... 53 Table 10 HEC-RAS calculated shear stress in channel for Scenario 8, mean annual equals 8.6 cfs. Zero shear stresses are highlighted in tan color ...................... ~ ..................................... 55 Table 11 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows in the ravine (catchment CCP) based on HSPF simulation WY 1949 -WY 2008 (525,960 hours) ..................................................................................................................... 56 King County v December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project EXECUTIVE SUMMARY May Creek in May Valley routinely flows out of channel inundating adjacent pastures and wetlands during the wet season. At the downstream end of the valley, the natural landscape constrains stream flows back into channel controlling flow rates leaving the valley before entering the ravine. This feature, coupled with the flat pasture lands, are reasons why flooded areas in the valley can take several days to sufficiently drain; returning to usable pasture lands. Combine this with a frequent occurrence of small stmms and portions of the pasture lands expectedly remain unusable for much of the wet season with frequent undesirable inundation continuing through spring and into the summer months. Given these conditions, the proposed project focuses on areas upstream leaving the natural constricting features unaltered. A study was conducted for May Creek in May Valley to evaluate stream channel capacity for existing and proposed conditions. This report contains hydrologic and hydraulic analyses (H&H) used to help optimize project design. Analyses include: assessment of channel capacity . for existing and proposed designs, assessment of flood frequencies and durations, assessment of channel competency to mobilize fine sediments and improve lifespan of the project, and assessment of impacts to erosivity in the ravine downstream of 148 th Ave SE. Two types of models were used, HSPF and HEC-RAS. HSPF is an U.S. EPA hydrologic watershed model used extensively in the Puget Sound region. The original model used was developed for the May Creek Current and Future Conditions report (King County \995). This model was updated with more current meteorology and channel routing to improve understanding of stream responses with longer periods of precipitation record and more accurate hydraulics. The HEC-RAS model used was last modified by Otak in 2006. For this study, new land survey work was completed in 2010 to update channel geometry and enhance resolution specific to this project study area, supporting simulation of several proposed channel restoration activities to reduce frequency of flooding without significant downstream impacts. At the lowest point in channel capacity under existing conditions, it is estimated that May creek begins to flow overbank at approximately 6 cubic feet per second (cfs). This flow rate is below the estimated mean annual flow rate of 9 cfs. Thus for most of the wet months, small portions of the pasture susceptible to these minor exceedences will remain inundated. Additionally, a tributary (Long Marsh Creek) historically deposits large gravels from a mostly forested subbasin in May Creek just upstream of a footbridge (approximately at river mile 4.6). These gravel deposits are large enough to backwater May Creek upstream for a couple thousand feet. This backwater condition facilitates the recruitment of more fines and vegetation litter that decays into organic muck. This muck then allows for an increase of vegetation encroachment of the channel further reducing channel capacity. The project study proposes an excavation of the channel between 148 th Ave SE and approximately 2000 feet upstream to an elevation of 308 ft (NA VO 88). Additionally, dense vegetation choke points downstream of 148 th Ave SE will be thinned to reduce impediment of low flows exiting the valley heading to the ravine. Hydraulic analyses estimate that post project channel capacity will be increased from 6 cfs to approximately 50 cfs before overbank flows begin. This improvement will effectively reduce most small storms from flooding the pasture areas. However, this channel improvement is still below the magnitude of an annual storm, thus May Valley is still expected to flood annually, but with shorter duration. This change in low King County vi December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project flow hydraulics frees up overbank storage for larger storms, such that results of this study estimate that storm events greater than the I O-year will either remain the same or marginally reduce in peaks. Storm events between the I-year (approximately 10% increase) and the IO-year (approximately I % increase) slightly increase, with all estimated increases or decreases calculated within model accuracy of a calibrated hydrologic model. Durations of flows near the 2-year (i.e. 200 cfs) and above are essentially the same. Durations of flows at 100 cfs again are nearly the same with an estimated difference in durations of approximately 400 hours over a 60 year period (525,960 hours, 0.08%). The higher the flow rates the less difference in durations to be expected. . Sediment mobility was also evaluated to estimate expected lifespan of the project. Channel bottom sediments in the project area are comprised mostly of silty fines and organic muck. With this type of channel bottom, it's estimated that a shear stress of 0.01 pounds per square foot is required to move sediment downstream. A mean annual flow rate (i.e. 9 cfs) was selected to evaluate success of the project given that flows at or above the mean annual level occur during most of the year, thus minimizing the possibility of any significant recruitment of fines or vegetation re-establishing in the channel. Post project, estimates of shear stress at 9 cfs are at or above 0.0 I psf except downstream of 148 th Ave SE in the wetland. There at low flows, deposition is expected to occur similar to existing conditions. These results signify that given the management of gravel deposition from Long Marsh Creek and ability to mobilize fines in May Creek, post project conditions should continue into the future with minimal deposition of fines reducing intended channel capacity. Based on the sediment transport study conducted downstream in the ravine (King County 2009), channel sediment mobilizes approximately at 233 cfs (refined from original flow rate estimates of275 cfs). This estimate along with marginal changes in durations of flows (maximum difference at 100 cfs with 0.08%), suggest no significant downstream impacts in the ravine resulting from proposed project designs. It is acknowledged that there is a level of uncertainty in estimates of stream channel sediment mobilization thresholds that could be lower. Given the maximum estimated difference in durations (at 100 cfs) is approximated to an annual average increase of 7 hours during the course of a year; these effects would likely be undetectable in the ravine. King County vii December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 1.0. INTRODUCTION May Creek valley experiences out of bank flooding on a routine basis every wet season lasting from several days to weeks at a time. The stream course is essentially in a bowl for approximately 2100 feet (river mile 4.6 to 5.0) between a footbridge upstream of Parcel #022305.9005 property down to Long Marsh confluence-just upstream of another footbridge. Long Marsh is primarily a forested basin with steep gradients. This characteristic gives the tributary the ability to deposit gravels large enough that May Creek is not capable to redistribute gravels downstream. Thus stream bed elevations at this location rise as more gravels are deposited. This accumulation then backwaters May Creek upstream causing more deposition of fines and decaying vegetation-·ultimately reducing conveyance capacity and increasing frequency of valley flooding. Like any natural stream system, larger but less frequent flow rates perform work on the stream banks and bed. Downstream of the valley, May Creek drops into a ravine where channel forming processes are expected. A recent sediment transport study was conducted at three locations in the ravine between Coal Creek Parkway and I48 th Ave SE (King County 2009) characterizing conditions capable of causing erosion in the ravine. Those results are used to evaluate effects of this proposed study. 1.1 Study Goals The goal of this study is to evaluate channel capacity for different alternatives in the valley area to maintain flow rates near I-year flood return interval by showing a reduction in frequency and duration of flooding. The reduction in duration of flooding is intended to affect only the mosi frequent, smaller storms, therefore unlikely to have any significant impact to the larger storms capable of eroding downstream conditions. Additionally, the proposed conveyance improvement should also be sustainable by passing through silts and retarding buildup of fines. In order to perform these types of analyses, a combination of techniques was necessary to evaluate detailed hydraulics and hydrology. Two types of models were used to perform the analyses, HEC-RAS for hydraulics and HSPF (Bicknell 2005) for hydrology. Both models used were adapted from existing models and updated to reflect current conditions. HEC-RAS (USACE 2005) was used to evaluate channel conveyance capacities and flooding inundations, while HSPF was used to provide statistical measures of durations and magnitudes of storm events. 1.2 Study Extent While the extent of the proposed channel improvements extend from river mile 4.31 up to river mile 4.99 (yellow highlight in Figure I), it was necessary to extend the boundary conditions to support the ravine erosion analysis and include the lower portions of the HEC-RAS hydraulic model down to the Coal Creek Parkway, river mile 3.59 (model extent shown as cross-sections in green in Figure 1). Similarly, the watershed model used encompasses the entire basin as shown in light red in Figure 1. King County 1 December 2010 .1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project -XSOJ1a..nn Dba"" --SIrODm' Figure 1 Locator map of study area in May Creek basin. King County 2 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.0. MODEL SYSTEM DESIGN Model design was dependant on available information and intended goals of the project. Modeling of the May Creek sy:;tem included a hydrologic (HSPF) and hydraulic model (HEC- RAS). The hydrologic model used was developed for the May Creek Current and Future Conditions report (King County 1995), while the HEC-RAS model was based on multiple modifications over time (King County 1995, Entranco 2002, Otak 2006) as projects occurred, with the most recent modifications performed by Otak in 2006. 2.1 Objectives The model system setup was designed to address May Creek Capital Improvement Project restoring hydraulic capacity with these objectives: I. assess channel capacity for existing and proposed designs, 2. assess changes in flood frequencies and durations, 3. assess channel competency to mobilize fines in May Creek through the valley, and 4. assess impacts to erosivity in the ravine downstream of l4Sth Ave SE. 2.2 System Overview In order to evaluate the stochastic nature of stream hydrology, it was necessary to perform a deterministic evaluation of the flow rates in the ravine and vaHey. Using the backwater computational abilities ofHEC-RAS, channel routing tables (FTABLES) were created to provide a detailed characteristic of reaches in May Creek in HSPF. Then using HSPF, hourly continuous stream flow data are simulated through the May valley and ravine. By simulating continuous hydrologic conditions for multiple decades (i.e. 60 years), the sequencing and permutations of selecting shapes and magnitudes of storm events are not needed. This framework then allows for a comprehensive durational analysis of exceedances of flow rates that inundate the valley and exceedances of flows above the incipient motion threshold in the ravine. 2.3 HEC·RAS Model Setup An existing model was used as a starting point for updating existing channel geometry with recent survey data collected in January 2010. Outside of the surveyed area, existing model definitions were used. Additionally, there was the intent to use the same stationing for location of cross-sections as was previously defined in the model within the surveyed area with cross- sections added where recent survey data suggested a change in topography that may not have· been present in the previous modeling efforts. This included a denser set of cross-section stationing to better encapsulate undulations of the stream profile where adverse slopes between segments were common or where vegetation choke points are occurring .. The existing model domain started a short distance downstream of Coal Creek Parkway, to two- thirds ofa mile upstream of where May Creek crosses May Valley Road at S.R. 900 (a little over 4 miles in total). King County 3 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.3.1 Survey Data King County recently surveyed much of the lower valley starting at Parcel #0323059038 property (approximately 950 ft downstream of 148 t \ to approximately 640 ft upstream of Parcel #0223059005 lower footbridge-approximately 3800 ft of stream length, during the month of January 20 I O. This surveyed area coincides with river miles: 4.266 through 4.99 (Figure 2). To further extend the model cross-sections from valley wall to valley wall, ground elevations using LiDAR data were used. Given the comprehensive extent of the field survey work, the addition of LiDAR was more for visualization rather than included in any of the hydraulic computations. The one exemption in the recent survey data were any bridge geometries upstream of 148 th street (including 148 th Street bridge). For these structures, existing geometry in the HEC-RAS model was used (see Table 1 for longitudinal stationing). o 0), \~t. StIfoc.e 2010 SUrvty ""aD -1.t4y(> ... -X$QJ1Li'1a Footbridge: Parcel # 0323059038 Figure 2 Extent of January 2010 King County Survey Table 1 Stationing for structures in the HEC-RAS model Station Description 7.07 Bridge-May Valley Road 6.95 Bridge-Renton-Issaquah Road King County 4 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 5.87 Bridge-164th Avenue SE 5.04 Footbridge-Upstream of Parcel #323059038 4.868 Footbridge-Parcel #323059038 4.612 Footbridge-McFarland's 4.455 Bridge-148th Avenue SE 4.28 Bridge-146th Avenue SE 4.265 Weir-Partial rock weir 4.114 Bridge-143rd Avenue SE 2.3.2 Flow Rate Change Locations In a stream system where tributaries occur or where attenuations from in-channel and overbank storage volumes reduce peak flow rates, a defined water surface profile may have changing flow rates associated to a set of cross-sections in the model. These flow rate changing locations in the hydraulic model were derived from two methods; either using observed gauge flows or results from continuous hydrologic model (HSPF). Statistical type flows such as mean annual, or 2 yr, etc., are based on outputs of the HSPF model, while any specific flow rate events evaluated were based on gauge data. In the hydraulic model, there were five defined inflow points starting near the headwaters as the upstream inflow down to where two lateral tributaries drain into the wetland on Open Space 803540, west of 148 th Ave SE. River mile stations for the flow change locations defined in the model are: • River mile: 7.605 (defined as catchment outlet NFK), head waters of May Creek • River mile: 7.05 (defined as aggregation of catchment outlets: NFK, EFK, and LKC), confluence of North Fork, East Fork, and Lake Kathleen, at SR-900 • River mile: 6.943 (defined as catchment outlet MVM), local drainages feeding to downstream of I 64 th Ave SE ' • River mile: 5.277 (defined as catchment outlet MVL), drainag'es leading to 148 th Ave SE • River mile: 4.388 (defined as catchment outlet CCP), drainages leading to Coal Creek Parkway. As an example, the mean annual water surface profile is defined using the stationing from above. Flow rates start at the headwaters with 4.6 cfs, and accumulate to 13.6 cfs entering into the ravine. Table 2 Example of Flow Change Locations in HEC-RAS for mean annual flow rate r Station mean annual King County 5 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 7.605 4.6 7.05 10 6.943 8.4 5.278 8.6 4.388 13.6 2.3.3 Channel Roughness Defined channel roughness followed previous modeling efforts developed by Otak. Essentially, channel reaches with substantial reed canary grass or collections of willow tree root systems were simulated with a channel roughness decreasing with increasing flow rates (Table 3). Otherwise, channel roughness in continuously choked reaches has a constant channel roughness of 0.07 and where channel was assumed clear, a roughness of 0.04. In addition to channel roughness, obstructions were used represent effective blockages either from dense clusters of willow trees, or heavy mats of canary reed grass on the banks. Table 3 Vertical varying roughness by flow rate 5 0.080 0.089 0.080 10 0.070 0.081 0.070 25 0.065 0.060 0.065 50 0.065 0.051 0.065 75 0.055 0.047 0.055 100 0.055 0.045 0.055 125 0.055 0.042 0.055 150 0.050 0.040 0.050 175 0.050 0.039 0.050 200 0.050 0.037 0.050 King County 6 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 250 0.050 0.036 0.050 300 0.050 0.035 0.050 350. 0.050 0.034 0.050 2.4 Hydrology A numerical hydrologic model (HSPF) developed for the 1995 May Creek Current and Future Conditions Report was used to simulate the hydrologic regime for a 60 year period. To generate this long period of record, the National Weather Service Sea-Tac metrological station was used for precipitation, and the Washington State University Puyallup station was used for evapotranspiration (ET). The period of record simulated was from water year 1949 through water year 2008 (10/1/1948 -9/30/2008). 2.4.1 Precipitation Precipitation is processed to hourly intervals, while the ET is processed to daily increments. However in the lower Puget sound basin, the Cascade foothills topography create an orographic effect of increasing precipitation the further east and closer to the mountain range. As a result, the observations made at Sea-Tac station needs to be translated to the May Valley basin. There are any number ofwllYs of doing this, one typical way is to scale precipitation using mean annual ratios of Sea-Tac to any local data in the basin. In general, this will provide a means for representing annual runoff volumes, but the scalar can be greatly divergent for a given season (e.g. over estimate storms in thl: winter and under estimate in the summer). This technique was used in the original Conditions report model. However, for this project a slightly more sophisticated technique was used to better preserve the Individual seasons (i.e. by month). In May Valley, there were two local precipitation stations used to scale the Sea-Tac data (King County station 37u for the lower parts of the valley, and 37v for the upper elevations of the valley. The Sea-rac data were then scaled on a monthly basis using linear regressions with a constant of 0.0 for ea'ch month, such that zero precipitation at SeaTac will be zero precipitation in May Valley. This allows for closer approximation of seasonal variability. Thus, in the HSPF model where one would use a scalar to adjust the Sea-Tac precipitation, the scalar is kept at 1.0 since the scaling was done prior to the model run. Monthly Scalars are listed in the table below. Table 4 Monthly scalars to transpose SeaTac precipitation to May Valley. January 1.172 1.044 February 1.150 1.096 King County 7 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project SeaTac SeaTac Month to 37V to 37U March 1.252 1.197 April 1.270 1.150 May 1.555 1.378 June 1.311 1.283 July 1.785 1.438 August 1.187 1.163 September 1.462 1.272 October 1.352 1.158 November 1.178 1.069 December 1.112 1.064 2.4.2 FTABLES FTABLES are user defined channel routing tables characterizing the relationship between stage, surface area, storage volumes, and flow rates. Four of these FT ABLEs were modified to reflect the hydraulics modeled using HEC-RAS. Using the multiple flow rate profiles defined in HEC- RAS ranging from mean annual flow rates to I OO-year flood frequencies, a series of cross- sections were used to define the transient storage HSPF utilizes for kinematic wave routing. For every cross-section in HEC-RAS the stage and wetted area can be highly distinct, thus an average was developed for each of the four catchments in HSPF. The groupings of cross- sections per catchment are listed below: • RM 3.5 though 4.451 were used for HSPF catchment CCP-FT ABLE 100 • RM 4.53 through 5.49 were used for HSPF catchment MVL-FTALBE 80 • RM 5.69 through 5.86 were used for HSPF catchment MVM-FTABLE 70 • RM 5.87 through 6.84 were used for HSPF catchment CFD-FTABLE 60. The depth and flow rates are weighted averages using the downstream channel length defined in HEC-RAS. Surface areas and storage volumes are summed up for each group of cross-sections defined above. While the overall differences are minor, this was performed for each geometric scenario and inserted into the HSPF scenarios for durational analyses. King County 8 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.4.3 Refined Estimate of Stream Flow Events for Phase II Sediment Study During the sediment study time period, there were two significant storm events that occurred, December 2007 and January 2009. Recorded stream flows during those events were determined to be unreliable (see Phase II, May Creek Sediment Transport Study). Additional investigation . into estimating the magnitude of those two events was instructional to better understanding the sediment mobilization that occurred during the two events. Flows at stations: 37 A, 37B, May2, and 37G were evaluated for the two defining storm events (December 2007, January 2009) used to estimate incipient motion, 37H was not installed until WY 2010. At stations Mayl and May3 no flow estimates were done, only stage was recorded (see Figure 3 for locations). Because it has been reported of active erosion/deposition influencing water levels at 37B, during the January 2009 event there is more uncertainty for flow estimates. Additionally, using a scaling method to synthesize records at 37B, Anchor estimated the peak flow rates for December 2007 and January 2009 to be very similar (339 and 348 cfs, respectively). However, upon further investigation the estimate used for the December 2007 event was based on a peak at 37A not appropriate for transposition to monitoring station 378. Figure 3 Gauge monitoring locations The peak flow for the December 2007 event at 37 A was near 600-cfs; however, that peak clearly occurs prior to the peaks measured upstream at the various continuous recording stations. King County 9 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Moreover, there is a considerable area of highly developed landscape draining to 37A below 378. This drainage area with relatively high amounts of impervious would respond to an event significantly faster than the upper May VaHey basin. This is illustrated by overlaying the various hydrographs for the December event (Figure 4). Thus, even though the daily peak flow rates for the various stations do occlir within the same day, the peak event at 37 A used should be just below SOO cfs--rather than the near 600-cfs for that event. 700 ,--------------_________ -, 6001-------------------------1 500 400 -37A -May2 378 300 -37G 200·j-----------/-~A~~~~~---------~ 100 j-----------/ 0~~==~~~~--L------L--------------~ 1211120070:00 1212f20070:00 12/3120070:00 12/4120070:00 1215/20070:00 ·1216120070:00 12f7120070:00 Figure 4 Flowrates for the December 2007 event Conversely, while the fast response of the lower drainage areas presents themselves in the January 2009 event (Figure S), that local maximum is less than the daily maximum coincident with the other stations. Thus the daily peaks used for the January 2009 event should be near 600-cfs at 37a (as was previously used). While the citation for the basis of the censoring the multiple years of continuous stream gauge records for 37a and 37b is provided, two apparent actions were taken in pre-processing the data: I) data were split into high flow and low flow events, and 2) some periods of record were filtered for use. Given the survey results at monitoring station May2, there were minor changes in channel geometry between the beginning and the end of the sediment study. Therefore, the continuous water level measured at that station was assumed to remain consistent throughout the sediment study period with possibly small adjustments to the associated flow rates. Thus all else being equal, a greater depth at that location would coincide with greater flows-assuming no downstream conditions influence the gauge. Reviewing the stages at May2 (Figure 6 and Figure 7) for those two events, January 2009 was observed to have a stage approximately O.S-ft higher than the December 2007 event. Thus, it is assumed the flows during the January event were greater than the 2007 event. King County 10 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 700 r--------------------------------------------------------------, 600 ~--~---------~ ----------1 500 ----~--~--------------------------1 400 ~~ ---------~ -----------------1 300 \----------- 200 1/112009 0:00 113120090:00 1{5I20090:OO 1nI20090:00 1/9/20090:00 1/11/20090:00 1/1312009 0:00 1/15120090:00 Figure 5 Flow rates for the January 2009 event 10-,-------------------------------, 9 .... ---. -----. ----- 7 -------- • 5 ---- ~=~ 3 ------- 2 1 ------- o~-_--_--_-----_-____ ----~_ -37A -May2 37. -37G 37G -37A -37. -May2 -May3 12/1/2007 121212007 121312007 12/412007 1215/2007 12/6/2007 121712007 121812007 121912007 12110/2007 ---------- Figure 6 Stages for December 2007 event. Note the obvious data errors in station 37G. King County 11 December 2010 I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project I I I I I I I I o 11G/20D9 1161'2009 1f7f2009 1f712009 1/8/2009 1f8J2009 11912009 1f9J2009 1/1012009 1/10f2009 1111/2009 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 I Figure 7 Stages for January 2009 event. Note the missing data for 37G. I I I I I I I I I King County 12 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project In lieu of investigating Anchor's approach on using a subset of data and estimate an independent peak flow for 37b, a moderately different method was performed but for preliminary review adequate for comparison to Anchor's approach. Peak daily flow rates (based on mean-hourly) were assembled from November I, 1998 through February 5, 2009 to be similar to Anchor absolute start and end dates-Ten plus years of data were used, and any days with missing data in either gauge were disregarded for this analysis. Then a robust regression (LOWESS) was performed on the entire set of peak daily data (subsequently, the same date ranges were used as in Anchor-the LOWESS results remained the same). In short, the LOWESS regression provides a sophisticated method for performing regressions applicable for linear and non-linear data making it not necessary to separate high and low storm events (Helsel and Hirsch, 2002). In addition to estimating the most likely value for 378, secondary regressions were performed on the positive and negative residuals of the primary regression to estimate a range of possible values based on the primary regression (Figure 8). LOWE 55 Regression plot f=0.25 300r-----r-----~----,-----,_----------, 250 200 :fl ! 150 250 ~ 200 iii ~ 150 ,., • 200 300 400 500 x-Values Simulated y-Values using LOWESS Regression Sequence Index (e.g. datenum) 600 • Observed -Regression Upper/Lower Jan 2009 • Observed --Simulated Lower Upper 7.34 X 10' Figure 8 Robust Regression (LOWESS-Locally weighted scatter plot smoothing) on Daily Peak Flow Rates from 11/111998 through 215/2009. X-a lis = 37A, V-axis = 378. Lower graph is a simulation of 378 using the regression and observed with time on [he x-axis, and flow rate on the y-axis. Results from the regressions estimates peak daily flows at 378 to be 233-cfs (with a possible range of 198 cfs to 260 cfs) for December 2007 (Figure 9) and 272-cfs (with a possible range of 218 cfs to 310 cfs) for January 2009 (Figure 10). Notably, this revised estimate more closely King County 13 December 2010 I I I I I I I I I I I I I I I I I I I r--------------------------- I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project matches the critical shear stress presented in the sediment transport study based on observed data. Additionally, performing the same analysis but not including data after January 13,2006,_ the flow estimates at 378 are estimated to be 240 cfs and 280 cfs (rounding to the nearest 10 cfs) for the 2007 and 2009 events. These are based on linear extrapolation of the LOWESS regression results since the magnitude of the peaks for the 2007 and 2009 events did not exist in the reduced dataset. Comparing the simulated flow rates using the robust regression to observed at gauging station 378, there are good correlations, r-square's, and slope's when using all data greater than 100 cfs and for data greater than 100 cfs but excluding gauge records after January 13,2006 (Table 5). A perfect fit would have a coefficient of 1.0 for each of those statistics and an intercept of 0.0. As such, the robust regression slightly under predicts observed. Table 5 Accuracy of robust regression for simulated versus observed for gauging station 37B using linear regression statistics, with observed on the x-axis for slope. Intercept Dataset Pearson r-square Slope All Data greater than 100 cis 0.87 0.75 0.91 Greater than 100 cis and excludes data after 1/13/2006 0.88 0.78 0.82 700,---------------------------------------------------, 600~-----------------------------------------------__1 sOOr------------------------I---~~----------------~ ~400r-----------------------1----------\_--------------__1 .!< ~ ~ 300-~---------------------~------------~-------------__1 200~-------------------f--~--~~~~--\-----------__1 l00-~------------------J~~------------~~~~'"----__1 O~ __ ~~--------__ ~ (cis) 10.1 14.8 ~37a_obs ---0-37b-sim -0 -Lower -C -Upper .......... 37b-obs 11/2912007 11/30/2007 121112007 12{212oo7 1213/2007 121412007 1215/2007 12/612007 121712007 Time (Dally) Figure 9 December 2007 Hydrograph of event King County 14 December 2010 700 6{)0 200 100 o Hydraulic and l!ydrologi~ Analyses of the May Creek Channel Restoration Project ~378-obs "'-37b-sim ..... Lower ..... Upper """-37b-obs 1/4/2009 1/512009 1t6/2009 1f712009 "8/2009 11912009 1/1012009 111112009 1/1212009 Time (Dally) Figure 10 January 2009 Hydrograph of event It is worth noting that although it was discussed previously about the faster response for drainages below 378, no effort was made on a storm event basis to match up peaks that might have shifts within the same day; which is similar to the method previously done by the sediment study .. One other comparison was perr.Jrmed using the HEC-RAS model developed for this project. At the May2 station, it was noted in the May Creek Sediment Transport Study, that the model was estimating approximately l-ft higher than observed after calibration. This was based on the flow rate of 340+ cfs for those two storm events. An attempt was made to reconcile where the monitoring stations were in the HEC-RAS model and known stations and locations in the ravine. Stationing between the HEC-RAS model and assumed known locations of the gauging did not reconcile; thus, matching up where the documented elevations are at the study sites and cross- sections in the model was not possible at this time. 2.4.4 Model Validatuon Edge of water was surveyed on two different days, January 8, 2010 and January 22, 20 I O. The January 8 survey was preceded by a small storm on January 5 cresting at 42 cfs as estimated at 148 th Ave SE bridge (KC Gauge 37G). Flows computed from the gauge during the survey on January 8 were approximately 29 cfs. The second survey occurred after a larger storm that began to recede January 16. The peak flow rate using the same stream flow gauge for that event was estimated to be 66 cfs. During the January 22 survey of edge of water, flows were estimated to have receded to a flow rate of 13 cfs as measured at KC gauge 37G (see Figure 12). King County 15 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Survey data for the January 8 event were transposed to the nearest cross-sections (RM 4.8612 and 4.8285)just downstream of Parcel #0223059005 footbridge and the January 22 survey work was taken upstream of the Parcel #0223059005 footbridge (see Figure 11 and Table 6 below for more detail). Figure II Edge of water survey shown in light blue lines. Table 6 Water surface observations, elevations in NAVD88. Station Date Left Bank Right Bank Avg. 4.992552 1/22 314.27 313.85 314.06 4.988154 1/22 314.20 314.20 4.9749 1/22 314.35 314.04 314.20 4.949 1/22 314.08' 314.14 314.11 4.937 1/22 314.17 314.14 314.16 King County 16 37G Flow Rate WS Profiles Dill. 13 cis 313.00 -1.06 13 cfs 312.99 -1.21 13 cfs 312.98 -1.22 13 cfs 312.94 -1.17 13 cfs 312.91 -1.25 December 20/0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 4.868 3/30 313.54' 40 cfs 313.60 +0.06 4.612 3/30 313.97' 48 cfs 313.47 -0.50 4.455 3/30 312.04' 48 cfs 311.89 -0.15 'Elevation is based on tape down from top of footbridge. King County 17 December 20/0 I I I I I I I I I I I, I I I I I I I I I I I I I I I I I I I I I I I I I I I 70 60 50 ol!! 40 ~ ., ~ .. 0:: 3 30 0 u:: 20 ilWlf IlUi\: 10 o Hydraulic and Hydrologic Analyses of the May Creek Channel Restorationproject· • I e ~~~ml lIlli\1 I ~.t:::.t::::.t:::.t:::.t::: .... .... I-> .... .... .... '&:"U"IO"I-.JOOIJ) Date/Time Figure 12 January 2010 Hydrograph for King County Gauge 37G (148th Bridge) King County 18 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Reviewing the surveyed water surface elevations shows that for those two dates, the elevations are virtually the same with the exception of the lower most point a halffoot lower (associated with the 29 cfs date) than the rest. This does present an inconsistency between the calculated flow rates and expected water surface elevations. With flow rates on January 22 less than half of what was estimated for January 8, one would expect the water surface elevations to be lower on January 22, when in fact they appear the same or higher with half the associated flow rate. MayCreek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment \4 3/2412010 MayCreekMalnsem Legend Ground 24500 25000 25500 26000 Meln Channel Dlslanee (ft ~ ~ "I.--rr- 26500 ~ . d ~ § -: f------ ~ g .n . .,.;. Figure 13 Profile of observed wllter surface elevations for January 8 (downstream of footbridge) & 22 (upstream of footbridge) with left and right bank elevations (LOB, ROB) plotted. LOB ROB [n addition, in the area when: edge of water was taken, overbank ground elevations are lower than bank elevations effectively creating a bowl outside the channel. This is consistent for about 570 feet (RM 4.88 through 4.99). The observed edge of water was either very near bank elevations (i.e. depressional area filled with water) or up to a halffoot above assumed bank. elevations (see Figure 14). Given the combined circumstances of inconsistent water surface elevations relative to flow rates, and the overbank depressional areas, conveyance out of bank in the pastures likely will behave in a couple of different fashions. When flows are initially going over bank, the flow pathways will act like a branch in the stream with its own water surface profile until it rejoins the mainstem. Then as flooding waters increase, the whole valley acts as one conveyance. As the storm recedes, the overbank flooding areas begin to behave like a slow draining lake (see Figure 15). Each of these conditions has a different hydraulic characteristic that may yield these inconsistent out of bank water surfaces for a given estimated flow rate. King County December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project f-v1ay Creek EXis~ing Condition NAVoa8 Plan: Scenario 1: KC Existing with Sediment v4 312412010 RS = 4.974923 .065 'II .065 'I \ 0 Legend 320 \ 5 4 WS 40 cfs 6 • Ground • Bank Sta , 318 OWS 40 efs 316 \ g ~ 6 ~ ~ " w 314 .'-..... I ---Dr 312 J I . 200 300 400 500 600 Station (ft) Figure 14 Example of cross-section where water surface elevation is same elevation as bank elevation (RM 4.974). Obstruction in cross-section is representative of dense canary reed grass on the banks. King County 20 December 2010 Hydraulic and Hydrologic Analyses ojihe May Creek Channel Restoration Project Figure 15 Example of overbank flooding slowly draining back into channel after a storm from 7 days prior (with some minor precipitation 4 days prior). Photo taken 3/19/2010. King County 21 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project January 14, 2010 Water Surface Observation A second observation of water surface was made during the larger storm event between the two survey dates on January 14, 2010 I :00 pm, at Parcel #0223059005 footbridge (tape down from top of bridge was.used). Using the gauged flow rate at 148 th Ave SE bridge of64 cfs, the water surface profile was within a two tenths of a foot to observed (see Figure 16). € 6 ] w May Creek Exisiting Condition NAV08a Plan: Scenario 1: KC Existing with Sediment y4 10 Main!tem WS 64cfs-Jan14 • Ground 3t8i----.-----~--------+_--------t_------~r_------_+---------1 3t7i---------~------~--------_+--------_r--------_r---------II·-----LO-B---- i-----------+-----j----\------j---------+----+---------I -~.---- Main Channal Figure 16 Observed water surface elevation for January 14, 2010 at 64 cfs at Parcel #0223059005 footbridge King County 22 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project March 30, 2010 Observed Water Surface Elevations In an attempt to capture water surface elevations for smaller storm events, another site visit was conducted. Water surface elevations were obtained by taping down from top of bridge. Additionally, flow rates were estimated using standard methods and velocity meters at each water surface observation point. Observations were made at three locations, l48 th Ave SE bridge, McFarland footbridge, and parcel #0223059005 footbridge with their respective estimated flow rates of 45 cfs (poor quality), 48 cfs (good quality), and 40 cfs (good quality). Long Marsh creek enters in upstream of the McFarland footbridge, hence the increase in flows at that measurement. Using these field measured flow rates, model accuracy validates with good accuracy with the greatest error equal to 0.50 feet. A water surface profile and observed water surface elevations is shown in Figure 17 below, and previously in Table 6. May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment '10'4 411/2010 320+=========;=======:~~==~~~~~~==~========~=========1r~=-, WS 48 efs • Ground LOB ROB , i---.--t----·-jf---J'i---j-----!----I--t,..-o----Jl ows 48 eta € j w Figure 17 Observed water surface elevation for March 30, 2010 at 48 cfs at three bridges. 2.4.4.1 Validation Summary This validation shows that the model under predicts water surface elevations for lower flows in the Valley floor anywhere from 0.06 feet to 1.3 feet (assuming calculated stream flows are accurate, but appear suspect) with most of the differences in the range of 1.0 feet and has better accuracy with higher flows (e.g. 48 and 64 cfs water surface observation). One hypothesis has been presented to partially account for the discrepancies, however there are multiple other plausible causes for the elevated water surfaces for low flows: some of which might be, error in gauge flow estimates at 37G, or unaccounted for choke points in the channel. At present, assuming the flow rate estimates are correct, it is very unlikely that water surface elevations King County 23 December 2010 I I I I •• I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project could be as high as surveyed. To reproduce those elevations for those low flow rates, the McFarland footbridge would have to be nearly completely damned to backwater upstream that high. While it is not known if this may have happened, it again seems unlikely. Therefore, while the accuracy of the survey data is not in question, the combination of assumed accuracy in flow rates and the edge of water survey in flooded conditions appear to represent a set of conditions neither characterized in the model configurations nor explainable in their contradictions. Therefore those two dates of observations should not be considered part of the validation. Conversely, model accuracy seems to be quite good for larger storms with error less than or equal to 0.50 feet. However, further model validation is still being pursued at this time targeting storms in the range of 10 to 20 cfs. King County . 24 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 3.0. SCENARIO DEVELOPMENT Hydraulic scenarios were designed with changes in channel geometry representative to the three proposed channel improvements: I) removal of choking vegetation points, 2) removal of choking vegetation points with increased sediment removal to an elevation of 308 feet, and 3) removal of choking vegetation points with some sediment removal to an elevation of 309 feet. 3.1.1 Model Geometry Scenarios were designed to characterize existing and proposed conditions in the valley. The first scenario includes characterizing existing conditions, and three other scenarios were designed to evaluate increasing levels of channel modification to address the objectives. The naming of the scenarios are representative of the stepwise process of developing the geometry files to get from one scenario to the next in HEC-RAS rather than suggesting that multiple additional scenarios were evaluated but not presented in this report. Scenario I: Existing conditions Survey work done in January 2010 included two channel bottom elevations: on top of soft sediment, and harder substrate assumed to be the more historical channel bottom. Existing conditions is meant to represent current channel geometry with channel bottom defined as on top of soft sediment. King County 25 December 20 I 0 I I I I I I I I I I I I I I I I I I I ,---------------------------~~--------- I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 7: Removal of vegetation choke points This scenario represents enhancements to the channel conveyance capacity by assuming Reed Canary grass is removed from the channel and banks, and Willow root systems are removed from the channel. The assumed channel bottom for this scenario and subsequent scenarios are based on the harder substrate sediment. This is based on the calculation of critical shear stress of silts in the channel and steam competency to mobilize the silts (see Section 4.0). ~yCrook Exlslting Condition NAVD88 Plan: 1) KC_SCN_1 312612010 2) KC_SCN_7 3126f2010 r===========r===========r====~M'~~~'M~'~M'~"~"Fm~=========r===========r====j'~~gl m _~ -Top of Sed . 3r2000 23000 24000 25000 26000 21000 Mllin ChaMel Olllance (It) Figure 18 Scenario 7 longitudinal profile in study area. The black line is channel bottom using top of sediment (used in Scenario I) and fuschia color line is profile of channel bottom to firm sediment. King County 26 December 20 I 0 LOB ROB -Chnnl Btm. Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8: Removal of vegetation choke points and increased sediment removal This is the most aggressive scenario with sediment removal assumed to occur between just downstream of 148th Ave SE bridge to the 125 ft upstream of McFarland footbridge-in total approximately 1025 ft at an elevation of 308 ft. The elevation of 308 ft was selected based on the apparent historical channel bottom at 148 th Avenue SE bridge crossing. 23400 23600 23800 24000 24200 24400 24600 Main Channeillsance (ft Figure 19 Scenario 8 showing existing conditions and proposed profile after sediment removal (308 ft) and nushing of silts. King County 27 December 20 J 0 I I I I I , I I I I I I I I I I I I I I I I I I I, I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 9: Removal of vegetation choke points and some sediment removal Approximately 518 ft of sediment (\25 ft upstream, 393 ft downstream) of McFarland footbridge is assumed to be removed to an elevation of309 ft. This elevation was selected to be similar to historical channel bottom elevations leading down to l48th Avenue SE bridge crossing and to evaluate an intermediate alternative. May Creek Exisiting Condition NAV08a Plan: 1) KC_SCN_1 312512010 2) KC_SCN_9 312512010 MayCraekMalnsem ---I--:--T:---I-~ilt ~~~~I Ltg,nd • op of Sedl men 3"1----t----t----+----+----t----t,f\\:-'----t---I--~~-: - -d \:--~-1 Channel Bottom ~~ '------~.--"----1-_ ~- 23400 23600 23800 24000 24200 24400 24600 Main Channel Dlmanea (ft) Figure 20 Scenario 9 showing existing conditions and proposed profile after sediment removal (309 ft) and flushing of silts. 3.1.2 Typical Channel Cross-Section Typical Channel Cross-section within the sediment removal segments was simplified for this study to assume existing channel geometry with the bottom dropped to the proposed elevation, In final design, sections where excavation exceed 2 feet below top of sediment, channel banks will be given side slopes to prevent bank sloughing. This simplification represents a conservative side of expected as-built conditions given the addition of side slopes will slightly increase channel capacity. King County 28 December 2010 I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: 1) KC_SCN_1 2) KC_SCN_8 I RS = 4.622613 V ~ Legend Ground -KC_SCN_8 • ank Sia -KC_SeN -• Ground -KC_Sa·c 1 314 --• I I ankSla -KC_SeN 1 I 312 g V 6 ~ I " w 310 I I 308 I 200 250 300 350 Station (ft) I Figure 21 Typical Channel Geometry of existing (black line) and proposed (fuschia line). I I I I I I I I King County 29 December 2010 I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 4.0. SEDIMENT TRANSPORT A particle size distribution was not performed for stream reaches in the valley floor; however, during field visits, it was noted that much of the channel bottom is extremely soft-in some places up to 3 feet of muck. Given the amount of bank vegetation and slow velocities, the soft sediments are likely made of up fine silts and organic matter from decaying vegetation. Given this condition, the particle size distribution (050) used for incipient motion in the valley channel was assumed to be 0.10 mm diameter (0.000328 ft). Aside from the percent of organic matter and possible colloidal conditions, incipient motion was calculated assuming the sediment is non- cohesive in nature and made up ofmostIy silt. While Shield's curve is nearly constant for substrate sizes largerthan 5 mm (Re* -400), it varies with smaller particle sizes. Thus it was necessary to compute the particle Reynolds number to obtain the Shields value (Guo 2002). Using a particle diameter of 0.1 mm, translates to a Re* approximately equal to 1.1, and Shields number of approximately 0.10 (Figure 22). Hence, the computed critical shear stress of less than 0.0 I psf is estimated for silty fines. on ... Guo-Shields Empirical Gi 0.1 !lIBIBllIE :c '" 0.01 0.1 1 10 100 ReO Figure 22 Guo-Shields Empirical Curve In Hec-RAS, the shear stress is computed with the following formula: r=}RS, where R is the hydraulic radius, and S is the energy slope. King County 30 1000 December 2010 Hydraulic and Hydrologic Analyses o/the May Creek Channel Restoration Project 5.0. RESULTS Summary of results include assessments of existing and proposed channel capacities, changes in flood frequencies and durations, stream competency to mobilize fines, and changes in erosion in the ravine. Reviewing existing conditions, it is apparent where hydraulic controls are located in the system (based on available survey data). During mean annual flows (8.6 cfs through the study area), control points are vegetation choking points in the wetland downstream of 148 th Ave SE bridge and mildly so upstream of 148 th and gravel deposition where Long Marsh enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04 (Figure 23). Similarly for higher flows (e.g. I year event), Long Marsh again controls water surfaces upstream for the same reach length. 10 Figure 23 Scenario I (existing conditions) water surface profile for mean annual (filled in water surface) and Conditions Report 1 year event (blue line with symbols). However, downstream of 148 th model runs show a convergence of water surfaces for the same flow rates for pre (Scenario I) and post (Scenario 8) project based on the transition from a valley to a ravine. This abrupt natural constriction changing from open wetland on valley floor to a well defined channel entering into the ravine become more controlling the larger the storm event. While water surface elevations may be lower for Scenario 8 in the wetland for the same flow rate, water surface elevations approaching 146 th Ave bridge converge to the same elevation (Figure 24). King County 31 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project , , t: ." , : ,.i.-t I , , I d g g , j s !-~ • s il ! , • t -f I " " " " +t 0 , 0 0 0 I I ;; I ~ ;; ;; I ' r---i-Ii --! !. , I • -·t't , \ t ---u • ~ Figure 24 Water surface profiles for the I-year (Conditions Report) for Scenario I and 8. Red circle highlights the convergence of profiles at I46th Ave bridge. Secondarily, removal of vegetation choke points in the wetland show a few tenths change in water surface, but given the model accuracy and very small amount oflost storage, this natural land form downstream of the proposed restoration channel activities will greatly control potential changes in erosion in the ravine, and less control from the bridge at 146 Avenue SE. In the following sections, three scenarios (plus existing conditions) were focused on for evaluations: • Scenario I-existing conditions, . • Scenario 7-removal of vegetation choke points, • Scenario 8-removal of vegetation choke points with increased sediment removal, and • Scenario 9-removal of vegetation choke points with some amounts of sediment removal. As previously mentioned there are three main control points in the system under existing conditions: I) the natural transition from valley to a ravine, 2) vegetation choking the channel downstream and upstream of l48 th Ave. SE, and 3) sediment depositions upstream of l48 th to the confluence of Long Marsh Creek. Each of the proposed scenarios improve in channel conveyance to varying degrees of success with Scenario 8 resulting with the ability to maintain waters in channel up to approximately 50 cfs for properties upstream of 148 th Ave SE. King County 32 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Estimated hydraulics for Scenario 8 elucidate that the control points effectively move down to the transition of the wetland to a channel entering the ravine for lower flows (Figure 25) and for high, infrequent flows (Figure 26). This characteristic supports the results of no increases in erosive flows to the ravine before/after the proposed project for the same flow rates. --to I - --t -_. I Figure 25 Water surface profiles at 50 cfs for Scenario 1 and Scenario 8. King County 33 December 20 I 0 I I I I I I I I I I I I I I I I I I I ,------------------------------------- I I I I I I I I I I I I I I I I I I s , 1 w Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure 26 Water surface profiles for the 100 year flood event for Scenario 1 and 8. King County 34 . December 2010 I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Capacity at the bridge located at 146 th Ave SE show that the 100-year (Conditions Report) flow I rate does go overbank (left side looking downstream) under both existing and proposed conditions and at the same elevation. Again it is worth noting that under the proposed project, 'I' the magnitude of the 100 year return period decreases, water surface elevations post project will be less (Figure 27). Similarly, the bridge downstream at 143 rd Ave SE shows to have capacity to pass the 100-year pre and post project (Figure 28) as well. It is worth noting that the bridge I geometry used for 143 rd Ave SE is based on previously existing geometry from the previous ' HEC-RAS model. A survey crew is s~heduled to resurvey this bridge and confirm existing geometry from previous modeling efforts. I May Creek 8<is,i19 Condition NA VD8B Plan: 1) KC_SCN_B 412212010 2) KC_SCN_1 412212010 RS = 4.28 BR Bridge #2 146TH AVENUE (RM 4.280) 10-----.08 '1·04+ .08--;-;--.,'1, r--~__;__-..., I Legend 320'------1--------1-------j-------'",----S 100-yr cur. ·KC~SCN_8 :=-:-::.,..:-c.-, -:-:.:=-~ WS 100-yrcur. -KC_SCN_1 • Ground • BankSla Station (tt) Figure 27 Water surface elevations (Scenario 1 and 8) for the 100 year (Conditions Report) at the 146th Ave bridge. King County 35 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses o/the May Creek Channel Restoration Project fv1ay Cre~k Exisiting Condition NAVDBB Plan: 1) KC 501 8 '-"<LU 'U 2) KC 5CN 1 4122/2010 RS=4.114 BR Bridge #1 143RO-;;"c.,,,c ~8) --,' ·no i4 Le.end / iws 100->,' c"': • KC_SCN. IwS 1 OO.yr cur. -KC SeN • Ground • OLV / Ineff • BankSta 3 '" g ~ II 6 ~ -------~ .., w .../ 3 :--, 0 WO 2'" 3,io .00 . SlaHon 1ft) Figure 28 Water surface elevations for the 100 year return period (Current Conditions) al bridge crossing al 143rd Avenue SE for Scenario I and 8. King County 36 December 2010 . ________________________ ..1 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 5.1 Improved Channel Conveyance Hydraulic analyses using HEC-RAS estimate that Scenario I (i.e. existing conditions) flow rates as low as mean annual (8.6 cfs) over top banks inundating pasture lands (Figure 29). In fact, channel capacity estimates for a few sections show that flows can go out of bank at rates as low as 6 cfs for existing conditions (Figure 30) while Scenario 8 (later in this section) keeps flows in channel up to 50 cfs. Thus calculations for evaluating improved conditions in May Valley are based on this threshold of flows between 6 and 50 cfs, such that any improved conveyance capacity will reduce the frequency and duration of minor storm events flowing out of bank. MayCrHk E.i.ltl,,!! ConditlDn NAV088 Plln: SceNl'io 1: KC ..-----1l #022305900 McFarland Footbridge ~~~i~~~:' ".~ I48 th Ave SE Bridge Figure 29 Perspective plot for Scenario 1 (Existing Conditions) mean annual now rate (8.6 cfs at 148th Street) King County 37 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I, I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment \4 .... 11 nn1n .... "", , ... , I,d, logend WS mean annual 31B1-~~~~~~~~-+~~----~--------+-~------~-------11 Gm~nd 3171-------,-,__-------+--------+-------+_-----,I--------II--lo-.--- 3161------~I__-----+--I----+-----+_---__ --_I-------II----RoB-- // 1\ /1\ ~ / irf € 3 -! ,,!_ / I-- / • / II 1 ill, 1 .. ~ 301 ~ ~ ~ l ~ ~ ! ~ 5: ~ ~ ~ ~ ~ ~ ~ , ;' ;;,;;' :; , "'" <, :il,.:ci,"," ::1, "'2DOO 23000 24000 2~100 26 00 '27(,00 28000 Main Channel ""an" (ft) Figure 30 Longitudinal plot for Scenario 1 (Existing Conditions) water surface profile for mean annual flow rate. King County 38 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 7 With complete removal of encroaching canary reed grass and Willow trees, flows are kept in bank between 14S th Ave SE and at the footbridge just downstream of Long Marsh Creek (Figure 31). However, this is predicated on the fact that all the silty fines are flushed out of the system. Without that successful element, in-channel capacity will be greatly reduced and more representative of existing conditions (Figure 32). One of the most effective choke points to be removed is just downstream of 14S th Ave SE. The combination of canary reed grass and Willow trees significantly reduce potential channel capacity at this location and a few others further downstream. 41112010 .a-4---l #022305900 McFarland Footbridge 14sth Ave SE Bridge Figure 31 Perspective plot for Scenario 1 and 7 (vegetation removal) 50 cfs at 148th Street. Light blue are for existing conditions while dark blue are for SClmarlo 7. King County 39 December 2010 I I I I I I I I I I I I I I I I I I I - ---, ------... .. ------- ~ .." 00' ElevatiCJ'l (tt) " g ;: '" :: .... " ~ ~ I '" .. ~ -_4.265343, DoNnstream, of, Ro. ~ .. _4.200185 KC,Survey.yeaL .. _ (") ... N .4.31'''''' I ---~--. @ ~ m " A ... ~ ..4.353836.KC_Surv,6'/...Y.EBr. _ m ;: g _4.378325 ~. " A4,11003 0 .. ~ .... A.432545.KC Survey.YOOr. S· A455 Brid;je,tt3.Hah '" ... (") ., A482C62.KC,SulV6'/.ymc2nO ___ => 0 N A507641 " ;' .p. _4.532Z7A '" .. o __ . 15 $ -g _4.56200a " '" ~ Z ~ <:> • A.600738 ~ ~ " " 5' _4.640315 :: :;;> " g= 0-~ ~ ~ • " ~ " , N • ... , ~ ~ " ~ 0 "-en 0 " ." " '" 0 · -$ .. ~ _. ~ = • ' " ~I .. , ~ .. ~ 0 • ... • 3 C S· ~ is" -N '" il<>. .. m (") ,,' 0 I = 0 '" ;.. C-o (") " ... Z " I ~ -'" .. :;; N1 . I ~~J II ~ .s; ~ _5.097003,otak xs.7875 o I ;;:. o fi 1::1N'i4 oI::ak Xl': ACII!i " 0 g: '" ~ ~ Q " IQ -" " " " ~ " ~ .. " , , :> " " "-"-~ '" -:l Q " ~ ~ • 0 '" "" a 0 °la 0 0 .. ;; " " c " " 3 ~ ~ • '" , , ~ ~ ~ ~ c '" I " " ~. c " " ~ , , c ~ '" -" ~ oQ. Q Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project With only a water surface reduction of half a foot through the study area, conditions upstream of Long Marsh are clearly unimproved given flooding still occurs at the mean annual flow rate (Figure 39). Furthermore, storm flows may begin to overtop downstream of Long Marsh depending on the magnitude of the event again not meeting project goals. MayCrltflk ExiSlling Cond,jlon NAVD88 Plan: 1) KC_SCN_7 41112010 411"'010 · l #022305900 ~ McFarland Footbridge ~ ~ 48 th Ave SE Bridge ~ I Figure 33 Perspective plot comparing Scenario I and 7 under mean annual flow rates King County 41 December 2010 I I I I I I I I I I • I I I I I I I I I I I I I I I, I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8 Under the proposed project design, Scenario 8, with vegetation removal and sediment removal down to 308 feet for approximately 1000 feet, the conveyance capacity increases to approximately 50 cfs in the previous sections where 6 cfs would be out of bank. This improvement effectively mitigates storms near the I-year magnitude (i.e. 61 cfs). Figure 34 shows that for 50 cfs, May Creek is over bank for existing conditions in the entire project area while for Scenario 8, flows are kept in-channel until the wetland area downstream of 148 th Ave SE (shown in dark blue). Hydraulic controls in the system coalesce down to the outlet of the wetland entering into a well defined channel 'Ieading to the ravine, with a small difference in water surfaces through the wetland area as a result of removal of vegetation choke points (Figure 35). One of the primary choke points to be removed affecting upstream of 148 th Ave SE is the combination of canary reed grass and clumps of Willow trees encroaching in the channel just downstream of 148 th Ave SE-significantly reducing channel capacity. ... 1 #022305900 McFarland Footbridge . -"<: •• ,.,., ~ 14th Ave SE Bridge Figure 34 Perspective plot for Scenario I and 8 overbank flooding with 50 cfs at 148th Street. Light blue areas are inundated areas for Scenario 1 and dark blue are Scenario 8. King County 42 December 20 10 I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project MayCreek Exisiting Condition 4/1/2010 I I I € I I I I I Figure 35 Water surface profile at 50 cfs for Scenario t and 8 I I I I I I I I I King County 43 December 2010 I .' I I I I I I I, I I I I' I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project In addition to lower flows, a review of higher flows was done. Focusing on downstream of the wetland through the bridge located at 143 rd Ave SE, the same return period of flood frequency was used, but with their respective flow rates of 229 cfs (Scenario I) and 240 cfs (Scenario 8) for the 2-year return period through the ravine. There is a marginal increase in water surface elevations downstream of I 46 th Ave SE of 0.08 ft and diminishes to 0.05 ft at I 43 rd SE (Figure 36). More importantly, the velocity changes are minimal as well with 0.10 ftls at 146 th Ave and 0.06 ftls down at 143 rd Ave SE. This marginal change in water surface elevations and velocities are essentially within the accuracy of the model validation. Thus, no effectively apparent significant changes between existing and proposed conditions at this flood frequency. Moreover, selecting any higher flow rates will result in even less differences between pre and post conditions. Figure 36 Water surface elevations for the 2 year return period (229 and 240 cfs) for Scenario I and 8. King County '44 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 9 The alternative scenario of removing sediment and choking vegetation to an elevation of 309 feet (Scenario 9) is less effective at keeping flows in-channel at 50 cfs through the project area (Figure 37). However flows are estimated to stay within bank between 148 th Ave SE and at the footbridge downstream of Long March creek confluence. However, this is primarily because of the element of removing vegetation choke points and the assumed flushing of existing silts with the increased velocities. Again, convergence of the water surface profiles converge at the natural control of wetland outlet (Figure 38). It is worth noting that flows are maintained in channel through the pasture areas up to approximately 40 cfs. 41112010 .A .. --....,l #022305900 McFarland Footbridge l48th Ave SE Bridge Figure 37 Perspective plot for Scenario I and 9 overbank flooding with 50 cfs at 148th Street. Dark blue areas are for Scenario 9, light blue are for Scenario 1 (existing conditions). King County 45 December 2010 I I I I I' I I I I I I I I I I I I I I I I I I I I I I I' I I --------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: 1) KC_SCN_1 4/1/2010 2) ~~ ~~N • 4/112010 Main5lem Figure 38 Water surface profile at 50 cfs for Scenario 1 and-9. 5.2 Updated Flow Frequencies Original flood flow frequency estimates in the May Creek Current and Future Conditions Report were based on a 42 year period of record from water year 1949 through water year 1990, and a single scalar to translate SeaTac precipitation to May Valley conditions using Bulletin 17-B (USGS 1982). As previously mentioned, current hydrologic analyses include additional data through water year 2008 (\ 8 years more data). This combined with the updated FTABLES for existing conditions, and flow frequencies have changed since the original analysis was done in the May Creek conditions report. Frequency analysis was done for two locations in the basin, flows draining through project area to 148'h Ave SE bridge (Figure 39) and flows down to Coal Creek Parkway. This illustrates how estimates of flood frequencies are dependant on period of record in addition to magnitude of events and any small changes in frequency estimates should be viewed with that understanding. Through the valley area, the magnitude of the 2 year flood frequency increases from 283 to 289 cfs (5 %). The increases in changes between Scenario 1 and Scenario 8 diminish to no change between scenarios at the 20 year event. In fact, flood events greater than the 20 year event decrease after the project. It is also worth noting that all the changes either increasing or decreasing are within the 95% confidence interval of existing conditions (Table 7). For convenience, the original May Creek Current and Future Conditions report flood frequencies are included in the table. King County 46 December 2010 Hydraulic and Hydrologic Analyses olthe May Creek Channel Restoration Project Table 7 Summary of flood frequencies for Scenario I and Scenario 8 for May Creek in the valley. 1.01 53 64 41 61 . 73 48 16% 110 1.11 94 108 80 104 118 89 11% nla 1.25 120 135 104 130 145 114 8% nla 1.67 163 182 145 173 191 155 6% nla 2 186 208 167 195 216 176 5% 165 5. 283 326 252 289 329 259 2% nla 10 351 414 307 354 412 312 1% 285 20 417 503 359 416 496 362 0% nla 25 438 532 376 436 523 378 0% nla 40 483 595 410 478 581 411 -1% nla 50 504 625 426 498 . 609 426 -1% 413 100 571 722 476 561 698 473 -2% 468 . Flows were interpolated and extrapolated from published 2, 10, and 100 year flow rates in the May Creek Current and Future Conditions Report. Similarly for the ravine, these changes in flood events are nearly the same. The 2 year flood event increases from 229 cfs to 240 cfs (5%). Flood frequency magnitudes decrease starting around the 20 year event. Again, this estimated change is within the 95% confidence range of existing conditions (Table 8). Table 8 Summary of flood frequencies for Scenario I and Scenario 8 for May Creek in the ravine. 1.01 67 81 52 78 92 62 16% 141* 1.11 118 135 100 130 147 112 10% n/a 1.25 149 167 130 161 179 142 8% nla 1.67 202 225 180 213 236 192 6% nla King County 47 December 20 I 0 I I I I I I I I I I I I I I I I. I '. I I I I I I I I I I, I I I I I- I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project !lWJ iY!mlW,. ~ -,:, "" ,~-,-~~': --'- 2 229 256 206 240 266 217 5% 208 5 349 400 310 355 404 319 2% nla 10 431 508 378 435 506 384 1% 357 20 513 618 442 512 609 446 0% nla 25 539 654 463 537 643 466 0% nfa 40 594 731 506 590 716 507 -1% nla 50 621 769 526 615 751 526 -1% 514- 100 704 889 588 694 864 586 --1% 582 -Flows were interpolated and extrapolated from published 2, 10, and 100 year flow rates in the May Creek Current and Future Conditions Report, Additionally with the proposed improved channel conveyance, attenuation of flows is marginally less thus slightly increasing flow frequencies on the lower end with the I year event increasing from 54 cfs to 61 cfs (Figure 40), Flow frequencies in the ravine were similarly indifferent between existing (Figure 41) conditions and proposed (Figure 42), King County 48 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 1 -MVL RBO Weighted Skew (G= -0.15274) Probability Plot . ___ ~._p71 .().cfs ___ . __ "3Jt .. 1.::..~!L .. _. __ .. __ .. _. __ . ____ ._. __ ._._. __ . __ ._._, __ .... _ ..... _ . ...!"~'.~ ... _._._._. __ ._~l?~L9.:.cJ§_. __ . __ ._ .. _,, ____ ._ ... __ ._ ... _ .. _._. __ . ___ .... _ .... __ . ____ ._.l.~~:.§:E!'., ___ ._ .. __ .... _. __ .. ____________ . ~ J!l • rr ---~-·---·----T ~ ~ ;; , c c 10' '" ill o ~ § o 0 ~ o ~ o § o 8 o ~ o ~ o Exceedance Probability ~ ~ a 8:3 o 0 0 00 J<';\..ur(l '" E"pt:!cld (year) (ets) {;::{s I -----_ .. --------_ .. -_ .. _- :l'iO.CO 61'; l(lO.CO 511 :iO.CO !jO~ ,,(1. ron m lS.CO 4::1101 ~O.C[) m IO.CO 3'Jl ~ .r.n Z9l Z .co :86 1.50 :H 1.2~ ::0 l.CI S~ -178 95%CI --Expeded * Weibull • 2008 • 2004 • 2008 • ',99, • 1990 • 1951 671 '" 51.;J ~t.!'> H1 ~ :'!'> ~Co'.> 286 IIH) He ua " Figure 39 Flow Frequencies for existing conditions using USGS 17-8 methodology for flows at 148th Avenue SE (catchment MVL) King County 49 December 2010 I '. I I I I I I I I I: I I I I I , I I I' I' I I .' I I I ~ * '" ~ ;; -• • '" 10' ~ ~ '" 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project • Scenario 8 -MVL R80 Weighted Skew (G= -0.12543) Probability Plot :t o N 560.7-cfs .,' ---.---.--------.--.-.. ----... ----------.. ---.-.7"" __ . __ ._..1~.J;£!L._. ___ .. ___ ... ______ . _____ ... ____ ~ I ! 0 0 0 0 ~ g M 0 0 0 0 ~ ~ 0 0 W M 0 " ~ N ~ ~ ~ ~ w ~ M N 0 0 0 0 0 0 0 0 .; 0 .; 0 Exceedance Probability 0 ~ N ;; ;; 0 0 0 0 0 0 0 0 0 !i"'lurr. 113 F",PE>C i.c1 II'e,H'i 'cflll (efs I .. -----" ----. --_ .. ---. -- ~O().Cl' 6H IOO.CO 5(:\ jC.CO 4~t'I 1,0.Cf! 178 2:', CO 4:i6 :0.(:0 11(, to.CO '.l~~ 5.CO 2B<:I 2.CO :~!l 1. ~() :!'>" J. 2~ : )0 l.CI 61 _178 95%Cl ---Expeded * Welbull • ,2008 • 2004 • 2008 • 1990 • 1991 • 2007 6-;,4 SH ~lJ 1",~ 4~4 1:1 3~ I 2<:12 19~' If,~ 12::' 50 Figure 40 Flow Frequencies using USGS 17-B methodology for proposed project design (Scenario 8) for flows drainging to 148th Aveneue SE. King County 50 December 2010 - 10' Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project • Scenario 1 -CCP R100 Weighted Skew (G= -0.12501) Probability Plot __ ._..2Q1 .. .1g __ ._.~ ___ . ____________ .. ____ .. ~" •. ......,""~ ____ 539J.:f!? _________ . __ .M _____ • ______ ._ ._. ____ ~~.4-cfs ____ .. ___________ _ . _. ____ 1i§2~~ ____ ._ .. ___ ._. ___ ._. ____ _ 229 <I-efs ,.Ii" -.----.. --.:.--.... -----.-----.. ~:r:;; g o l8 o o 0 I.tl (\oj ... ~ q ~ a ~ cioooo Exceedance Probability I<",lurr. m rAFael d l,'earl lefs) 1:::1 !'l 1 ---------------------- .riO.CO "')' I.l~. lllO.eO '" :'O.CD GIl {O.Cfl :,'If, 2~. CO ~39 ~O.t:fl :,13 10. GO 431 ~.CO :119 2.CO 2:9 1.50 :!If, 1.2~ :49 l.Cl " -178 95%CI --Expeded * Weibull • 2008 • 2004 • 2008 • ,gg, • '951 • '990 1.l2~ 12~ 6.;0 I}I~ !)~O ~:3 '" iSZ ::::9 18 • H' G4 Figure 41 Flow Frequencies using USGS 17-8 methodology for existing conditions at Coal Creek Parkway (catchment CCP) King COllnty 51 December 2010 I I I 1 I I' I I I I ·1 '. I I I I I I I .' I 1\ I I~ I I I I I • ' I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8 -CCP R 100 Weighted Skew (G= -0.082482) Probability Plot •• M. ___ • __ 21?.J.:f!!._ ..... __ .. _._ .. ___ .. _ .... _ .... _. ______ .. __ .. _.on ._ ___ . ___ ... 1~.J~;:.£f~ ______ ... __ .. __ . ___ . ___ .. _ .. _._._. __ _ ..... ¥ " 355 5.cfs _d' -:: , •••• -----_ ... _ ..... __ ... _------_. __ . __ ._-----_.-_.-~ -,.,. m 0 0 0 0 ~ 0 M 0 0 0 0 m m ~ 0 0 ID 0 M 0 0 ~ N m m m m ~ ID ~ M N d 0 0 0 0 0 0 0 0 0 0 0 0 0 Exceedance Probability 0 ~ N ;; ;; 0 0 0 0 0 0 0 0 0 Ii<'lLun, no E.<I''''Cl.d (ye"n (e1 ~I I.::fs) ---------------------- ~ao. ell 7/ ~ lO(l.CO ('<1' :.O.CU &15 f,ll. CO ~'l() 2~.CO ~37 :O.Cil 51~ lC.CO 4J~ :.r.o 3;,~ Z .CO '" 1.5e, ~<if, 1. .I:' :61 1.e1 " -178 95%CI --Expected * Weibull • '2006 • 2004 • 2006 • 1991 • 1990 • 1951 !!13 '" tlJ2 00' ':in "1:2 nSo ~,5~ :~:) H:> 1!;J!l 75 Figure 42 Flow frequencies using USGS 17-B methodology for proposed project design (Scenario 8) at Coal Creek Parkway (catchment CCP). 5.3 Reduced Duration of Flood Inundation for Smaller more Frequent Events Reductions of durations in pasfure flooding are quite substantive given the conveyance improvement from 6 cfs to 50 cfs. Using HSPF, a watershed model was run for a period of 60 years (water year 1949 through water year 2008) at one hour time steps for each scenario. Using the continuous output from the model, a durational analysis can be perfonned estimating the length of exceedances at any given threshold . It is worth noting that these analyses are a simplification of acfual conditions. These results do not take into account the time it takes for the flooded pastures to recede back into the channel after a stonn event, thus acfual reductions in durations of inundation will be less than presented here, but for the purposes of demonstrating improvements this method is valid. Relevant for valley flooding, the two key thresholds of interest are 6 cfs and 50 cfs where flows are either out of bank or in-bank-post project. Under existing conditions, flows are forecasted to be over bank, on average, 24-percent of the time or roughly 3 months of the year. Which given the episodic nafure of stonns in the Pacific Northwest, and the unaccounted time for King County 52 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project receding waters, this could be interpreted as multiple more months of inundation. Durations of flows flooding the pasture for the proposed design (Scenario 8), shows a significant decrease assuming flows are not out of bank until flows exceed 50 cfs. For this threshold, flooding is expected to occur, on average, 3 percent of the time per year or roughly 2 weeks (Table 9). Again, it is important to note that this does not account for time draining the pastures after an event has occurred, thus the effective reduction in pasture flooding will be less than presented here. Reductions in duration of flooding are likely to occur when storm magnitudes begin to diminish in spring and summer with peak flow rates more likely to be less than 50 cfs. While the other two scenarios are included in the durational analysis and in the table below, the threshold for over topping banks is less than 50 cfs, hence reductions of durations will be considerably less with Scenario 7 (removal of vegetation choke points) the least effective, marginally increasing in-channel capacity to approximately 8 cfs before flows go out of bank. While Scenario 9 (removal of vegetation choke points, some sediment removal) does significantly improve conveyance capacity over existing conditions (i.e. approximately 40 cfs in channel capacity), over bank flows are estimated to occur 33 percent more of the time (i.e. 4 % of total duration versus 3 %) relative to Scenario 8. Table 9 Percent of time nows are equaled or exceeded at each of the now rate thresholds for nows passing through the project area (catchment MVL outlet at 14S" Avenue SE) based on HSPF simulation WY 1949- WY200S. 6 24.04% 23.77% 23.41% 23.49% 10.4 13.77% 13.65% 13.44% 13.50% 28 6.03% 6.01% 5.99% 5.99% 40 4.01% 4.02% 4.04% 4.04% 50 2.94% 2.96% 2.98% 2.98% 75 1.39% 1.42% 1.46% 1.45% 100 0.70% 0.74% 0.78% 0.77% 150 0.26% 0.26% 0.29% 0.28% 175 0.18% 0.18% 0.19% 0.19% 200 0.12% 0.12% 0.13% 0.12% 233 0.08% 0.08% 0.08% 0.08% 275 0.04% 0.04% 0.04% 0.04% 300 0.03% 0.03% 0.03% 0.03% King County 53 December 20 I 0 I I I I '. I I I I I I I I ,I I I I I I I 'I I .' I I I I I I' I I I~ I I: I I 5.4 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project , , ' ~,1i!tlJ>9 "~ ~ 00ilillIt!l 00ilillIt!l f; m it. 1\ 7J @ @ i. ~ ~- 350 0,02% 0,02% 0.02% 0.02% 400 0.01% 0.00% 0.01% 0.01% Flow Rates Competent to Pass Silts through the System Based on the estimated incipient motion for silts, shear stresses equal to or greater than 0.004 psf are capable to mobilize silty-fines assuming non-cohesive and median diameter size of 0.000328 feet (0.10 mm). Using HEC-RAS computations of shear stress, it is assumed that shear stresses greater than or equal to 0.0 I are capable to mobilize silts. Two flow rate profiles were evaluated for their competency: mean annual flow rates and 29 cfs. The goal was to obtain shear stresses above 0.01 for the mean annual flow rate of8.6 cfs throughout the project area. Results show that shear stresses do equal or exceed 0.0 I through the project area except for in the wetland downstream of 148 th Ave SE bridge (Table 10). The threshold of29 cfs is meant to represent that typically, there is at least one event of that magnitude each month between November and May-with a few exceptions during dry months. However, barely meeting the minimum target is not optimal given the possible inaccuracies in assuming non-cohesive silty fines. Fines with a diameter of 1 mm or greater require shear stresses above what the mean annual flow rate can produce. Moreover, during summer months when flows are their lowest, it would be expected that silts will settle on the channel bottom based on these results. This introduces another uncertainty about characterization of the fines when the next wet season starts. If vegetation has started to grow in the channel bottom, the root system will bind the soils together thus increasing the incipient motion threshold. Therefore, it is unclear what levels of flow rates are necessary to eradicate any new growths that may occur in the channel bottom during the summer. These results are also dependant on the relocation of where Long Marsh creek deposits gravels during storm events. This tributary has clearly been shown in the past to deposit enough gravels to effectively backwater May Creek upstream of its confluence. Additionally, shear stresses in May Creek are far below forces necessary to mobilize gravels that are being deposited by Long Marsh creek. King County 54 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table 10 HEC-RAS calculated shear stress in channel for Scenario 8, mean annual equals 8.6 cfs. Zero shear stresses are highlighted in tan color . ~ ~ ~ IMll!IDl ~ IMll!IDl ,-------------,------~ . . -1 : ~ ~ Z@c9Iil I ~ ~ Z@c9Iil ~ ~ Z@@ll\ I 4,9926 0,01 0.03 4.6120 McFarland footbridge 4.4550 148th Ave SE Bridge 4.9882 0.02 0.07 4.6112 0.01 0.03 4.4512 0.01 0.03 --------~ 4.9749 0.1 0.25 4.6067 0.02 0.07 4.4454 : 0: 0.01 4.9687 0.53 0.26 4.5754 0.01 0.05 4.4325 0.01 0.04 4.9491 0.04 0.09 4.5628 0.02 0.05 4.4265 0.01 0.06 4.9372 0.03 0.08 4.5516 0.01 0.04 4.4155 0.01 0.04 4.9120 0.01 0.05 4.5429 0.01 0.03 4.4116 0.01 0.04 ,----I 4.8874 0.01 0.06 4.5323 0.01 0.02 4.3 947 1 Or 0.02 I : 4.8701 0.29 0.32 4.5144 0.01 0.04 4.3876 I oi 0.01 I l. Parcel #0223059005 I 4.8680 footbridge 4.5076 0.01 0.04 4.3783 r 0 0 I 4.8658 0.18 0.18 4.5055 0.01 0.03 4.3713 I ,---0, 0.01 I r I r 4.8613 0.42 0.12 4.4974 0.01 0.03 4.3694 ! O! 0.01 4.3538 1 , 4.8286 0.02 0.06 4.4821 0.01 0.04 o j 0.01 L . --_. -~ 4.7885 0.01 0.04 4.4814 0.01 0.03 4.3360 0.04 0.07 4.7495 0.04 0.1 4.4788 0.01 0.03 4.3234 0.06 0.08 4.7207 0.02 0.07 4.4729 0.01 0.03 4.3195 0.05 0.08 4.7087 0.02 0.06 4.4648 0.01 0.03 4.3108 0.14 0.23 4.6403 0.01 0.02 4.4613 0.09 0.14 4.2892 0.04 0.07 4.6226 0.01 0.04 4.2861 0.31 0.21 4.6177 0.02 0.06 4.2826 0.06 0.09 4.6138 0.03 0.09 King County 55 December 2010 I I I I I I I I I t I' I I I I I I I '.' I I I I I' I' I I I I" I I I I I I -------------------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. 5.5 Durations of Flow Rates in the Ravine Using the results in the May Creek Phase 11 Sediment Transport Study, erosive flows in the ravine were observed to occur in the range of 73 t0340 cfs, and a theoretical estimate of incipient motion approximate to 275 cfs. Refinements for the flow events used in that study, presented in this study, narrows the range of observed mobilization of sediment estimates for incipient motion to a range of 75 to 275 cfs (rounding to the nearest 5 cfs). For this study, characterization of changes in erosion in the ravine are based on evaluating durations of flows above the defined incipient motion. As previously mentioned, an HSPF model was used to estimate continuous flows at one hour increments for a period of 60 years (from October 1,1948 through September 30,2008) using scaled historical precipitation and evapotranspiration. This method enables a statistical characterization using observed historical climate data for May Creek in the valley and ravine that would not be available otherwise. Thus, any phases of dry years, wet years, and everything in between are contained in this analysis as opposed to any potential climate bias using local data of shorter time spans. Durations of flows evaluated in the range of 75 cfs or greater for the ravine show that there are small increases that progressively get smaller the higher the flow rate. Comparing Scenario I to Scenario 8, these increases start with 0.07 percent increase at 75 cfs and become less than 0.01 percent for flow rates at or above 275 cfs. As an example, there is 0.003 percent (i.e. 0.00003) increase in duration of flow rates between 300 and 350 cfs. Over 60 years of duration, that is equivalent to 15 hours increase or on average 15 minutes more per year (Table II). This level of detail is beyond the accuracy of the calibrated model, but any biases in the models would be consistent such that relative comparisons between scenarios like this are valid. Table 11 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows in the ravine (catchment CCP) hased on HSPF simulation WY 1949 -WY 2008 (525,960 hours). "" .,"''''~ ~"'"~,. . ~ ~' ~;.,-" ~7-, f • --']:;:n' -;~.",~ ~~~.~; OO';W 11 7J @. @'.'j " ... -,.~)<;ao~{.Ji:."'ti., ,. ~>r;;"_'~~:"'~'~~'~ 6 43,26% 43,15% 42,97% 43.00% 10.4 25,06% 24.89% 24.63% 24.68% 28 8.84% 8.77% 8.66% 8.69% 40 6.10% 6.10% 6.06% 6.08% 50 4.60% 4.61% 4.61% 4.61% 75 2.41% 2.44% 2.48% 2.48% 100 1.32% 1.36% 1.40% 1.39% 150 0.47% 0.50% 0.52% 0.52% 175 0.33% 0.34% 0.36% 0.35% 200 0.23% 0.24% 0.26% 0.25% King County 56 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 233 0.15% 0.15% 0.16% 0.16% 275 0.10% 0.10% 0.10% 0.10% 300 0.072% 0.074% 0.075% 0.075% 350 0.041% 0.041% 0.040% 0.040% 400 0.027% 0.029% 0.028% 0.028% 5.6 Other Considerations Presented in all the scenarios except for Scenario I (existing conditions), the channel bottom profiles were based on survey elevations taken to the harden channel bottom and not on top of the soft sediment. This assumption is based on the fact that after the project when velocities are improved, existing silts will flush out of the system over some period of time. Although in-channel silt mobility analysis indicates improvements will restore competence to mobilize this material, there are in-channel features that will likely retard this process including re-vegetation by aquatic plants during summer base flow conditions, thus changing soil inobility characteristics and estimates of flushing for the next wet season. Lastly, the modeling verification is still in progress. Low flow conditions in the 10 to 20 cfs range should be validated to a reasonable accuracy, but given how well the model simulated for slightly larger flow rates (i.e. > 40 cfs), it's reasonable to assume that the model represents conditions at lower flows acknowledging that there will be numerous specific locations in channel geometry and vegetation blockages not included at every location. However, it is intended to include all major features. At present, the results of the modeling characterize out of bank flows in the 6 cfs range along with the durational analyses estimating that on average over time, pasture areas are flooded on average 3 months out of the year and likely longer. However given the preliminary hydraulic verification, existing channel capacity is uncertain at this time. King County 57 December 2010 I I I I I I I I I I I' I ,- I, I I I I I ,--------------------------------- I I I I I I, I I, I, I I I I '." I' I I, 'I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 6.0. REFERENCES Bicknell, Brian, et aI., July 2005, HSPF Version 12.2 User's Manual. Prepared for U.S. EPA- NERL, Prepared by Aqua Terra Consultants. GeoEngineers,2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid-Sound Fisheries Enhancement Group. Guo, Junke, 2002. "Hunter Rouse and Shields diagram," Advances in Hydraulics and Water Engineering, Proc. 13 th IAHR-APD Congress, Vol. 2,1096-1098. Helsel, D.R. and R, M, Hirsch, 2002. Statistical Methods in Water Resources Techniques of Water Resources Investigations, Book 4, chapter A3. U.S. Geological Survey. 522 pages. King County, 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler Environmental Corp. King County, 2002. May Creek Sediment Wedge Removal Project-HEC-RAS Model. Prepared by Entranco, Inc. King County, 2009, May Creek Sediment Transport Study. Prepared by Anchor QEA, LLC. Otak,2006 USACE, March 2008. HEC-RAS, River Analysis System-Hydraulic Reference Manual (Version 4.0), U.S. Interagency Advisory Committee on Water Data, 1982, Guidelines for determining flood flow frequency, Bulletin 17-B of the Hydrology Subcommittee: Reston, Virginia, U.S. Geological Survey, Office of Water Data Coordination, [183 p.]. [Available from National Technical Information Service, Springfield VA 22161 as report no. PB 86 157 278 or from FEMA on the World-Wide Web at (http://water.usgs.gov/oswlbulletinI7blbulletin 17B.html). King County 58 December 2010 I. I I I I I I I I I I I I I I I I I I tQ King County Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296·6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov February 9, 2011 EXHIBIT 27 ity of Renton fanning Division AUG -5 2011 TO: Doug Chin, Senior Engineer, Water and Land Resources Division, Department of Natural Resources and Parks FM: Julia Turney, L.G., Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation and " Jeff Burkey, Hydrologist, Water and Land Resources Division, Department of Natural Resources and Parks RE: May Creek Drainage Improvement Project: SE May Valley Road and 148th A venue SE Sediment Assessment Introduction This memo provides information on sediment conditions in May Creek from approximately 148 th Avenue SE upstream to 164th Avenue SE. This evaluation addresses geomorphologic controls, sediment sources, sediment behavior in the drainage and how the project actions are likely to influence future sedimentation in May Valley. The purpose of the following background evaluation is to provide information to assist King County Department of Natural Resources and Parks, Water and Land Resources Division in the design process for a drainage improvement project in May Valley. The proposed project location is shown in Figure I. Two questions have been raised regarding sediment associated with the May Valley drainage improvement project: Question 1: Will the project change sediment delivery downstream to May Creek? Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? --- -.. .. - ----.. -.. -.. -.. .. P.---------------------------------------------------------------------------------------" May Creek Channel Restoration Project Proj ect Vicinity • Study Area o Mile Markers Stream • Incorporated Areas Cougar Mountain Wildland Park ~ • N ~?- March 2010 t&I King County a 95 190 380 570 760 ..... iMo_ ........... _ .. ~.b_ ........ "" ~c~ .... *-.... ..,.~_ ..... Ir:I~'" ... _ ........ ...... I4I'IC ___ ........ __ .... _. __ ..... _ .......... 10_..:1\1. ..., ................... 01 ""* .a. ... .,._w.-k'" 1tHo ....... ntilIolltW .... db ..... "' ... .,"'tduol I4JoeC~"'''1IOI M "'Io*", • .., .. _.l l"', .... d., IIoci6orQl, ...... _IIIUI Uowog . "' ......... Iout ... r..m.Ito,l..t __ ................... _ ... .... , ........... h ........... ~d_ ... _ ,." ..... ot_ .... ,., .• II'\IIIIIIft ........ ,11:,.. ......... .. ~~ ... ~m* .... ~c~ Figure 1 I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 3 There are a number of factors that were not available for the assessment: • The actual suspended sediment loads in May Creek in the project area, the suspended and bed loads from the tributaries and the relative contribution of sediment from different sources are not known. • The change in sediment loading over time due to changes in land use in the basin; logging, development, agriculture and channel dredging is not known. • All ofthe tributaries provide some amount of sediment to May Creek within the valley but the actual volume is not known. Long Marsh Creek delivers gravel to silt sized sediment to May Creek. A depositional area of gravel and sand is visible in May Creek. Estimates of the delivery rate for Long Marsh are made from surveyed elevation changes between a sediment-removal project in 2002 and 2010. • Beaver dams above the project area trap sediment and release sediment periodically due to flooding or breaching. An assessment of the sediment behavior presented here is based on published basin information, aerial photo interpretation, survey data from 1965, 1979, 1993, 2002 and 2010, a soil-loss analysis by Jeff Burkey, sediment samples from the May Creek channel, and May Creek survey records and studies conducted for the project. This assessment provides a working hypothesis about sediment movement in the valley and the basis for future investigations. Background Geology and Stream History The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The valley is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Formation. The formation is composed of volcanic tuff, fine- grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop west of I 46th and forms a physical boundary between the downstream ravine and May Valley upstream. The geologic map is shown on Figure 2. The creek gradient within May Valley is 0.2 percent and the valley is predominately a depositional environment. Aerial photography and Lidar image of the valley show evidence of pre- dredging channel meanders. Historic survey mapping from 1872 shows May Creek as a meandering stream and Tributary 0291a extending north to join May Creek just south of Indian Meadows rather than the current confluence approximately 1,440 feet west of I 64th Avenue SE. The alluvial fans from Indian Meadows and Long Marsh Creeks appear on the 1872 map and the mapped location of May Creek is routed to the southwest around the higher elevations of the Long MarshlIndian Meadows alluvial fans. The historic channel map for 0291a is consistent with Lidar images showing meander scars in the valley. (Aerial photos and historic map information is located in Appendix A). May Creek was dredged to form a linear channel between 1910 and 1936 (Foster Wheeler, 1995). A description of May Creek by Bretz (1913) describes May Valley as a "swampy, wide bottomed old channel". A project plan dated 1935 (King County Map Vault) shows creek modifications extending from Lake Washington to I 64th Avenue SE. I I I I I I I I I I I I I I I I I I I May Creek, May Valley • Legend Qw-Wetland Deposits Organic Rich Sediment Qvr-Recessional Outwash Deposits Sand and Gravel Qvt-Vashon TlII Compacted Mix of Slit Sand and Gravel Tpt-Tukwila Formation-Mix of Volcanic and Sedimentary Material 1050 10 20 :lO 40 Mile. - ----- N + Figure 2 tQ King County I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 5 Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited shrubs or trees. Periodic dredging is reported during the 1940s through 1960s (Foster Wheeler, 1995). Property owners may have removed sediment periodically. Sediment Sources to May Creek Agr!culture and Pastures In the immediate area of the proposed project there are roughly 8.4 hectares of active animal pasture that abut the stream on both sides with a few animal access points to the stream water (assumed watering holes). Under existing conditions, these animal pasture areas are flooded at stream flows below mean annual flow rate (8.6cfs)-over-bank flooding begins approximately at 6 cfs at the low point in the bank. Thus, its likely sediments that may not have washed off during a rain event with overland flow will be washed off when the stream-system capacity is exceeded and floods overbank. After a flood event, there does not appear to be any visual deposition of sediments resulting from the stream itself and upstream conditions but erosion rills are present in the pastures. Thus, it is assumed that sediments suspended in the water column that flush into the. pasture retreat back into the stream system. Given this condition with the added animal activity, sediments from soil disturbance would be additive to upstream sediment loads, thus increasing sediment loads downstream. The proposed project goal is to reduce frequency of pasture flooding, thus sediment loads, from a frequency of any appreciable storm to a near one-year storm frequency. To assess potential sediment loads from pastures in the project area, similar studies in the Green River watershed were evaluated (King County, 2007). The Green River studies have estimated sediment loads (via total suspended solids) ranging from 50 to 170 kg/ha/yr; residential = 158 kg/ha/yr, commercial = 172 kg/ha/yr, forest = 110 kg/ha/yr, and agriculture = 50 kg/ha/yr. Literature values (Burton and Pitt, 2002) are significantly different with 10, 420, 3, and 343 kg/ha/yr for residential, commercial, forest, and agriculture, respectively. Monitoring stations used for agriculture land use in the Green River watershed study were downstream of pasture lands in ditches that had significant amounts of choking vegetation in them just upstream of the sampling station. Given the relative position of the sampling location and the proximity of vegetation upstream, one may expect the Green River sediment loads to be lower than expected because of the vegetation trapping wash-off loads. Consequently, estimated loads from the May Valley pasture areas are then estimated in the range of 50 -340 kg/ha/yr (assumed 200 kg/ha/yr average). Simplistically if we estimate loads from the pasture lands to be 200 kg/ha/yr, and post-project loads are reduced in half, then for a ten-year period and 8.4 ha, there is a reduction of 8.4 metric tons of sediment contribution to May Creek. An estimated range would be a reduction of 2.1 to 8.4 metric tons of sediment contributed to May Creek. Doug Chin February 9, 2011 Page 6 Hydraulic model results estimate that the channel capacity to carry bedload and suspended sediment through the project area will be increased after the proposed project by increasing the channel efficiency. Velocities associated with lower flow rates are increased with the removal of vegetation choke points in the channel along with channel- bottom high points that otherwise create backwater conditions conducive to deposition, while depths are increased with a lower channel bottom in conjunction with more water kept in-channel rather than over bank because of improved flow-rate capacity. Reduced overbank flooding into reed canarygrass may allow the annual volume of fine sediment and muck moving downstream to increase on a yearly basis. Higher flow or flood events would continue to carry stored in-channel and off-channel fine sediment downstream in a larger pulse. rather then metering sediment at lower flows. The cumulative total volume of sediment over a longer time frame. ten years for example, would not be expected to change. May Creek bottom sediments were sampled by the King County Department of Transportation Materials Laboratory (King County, May 2010 and October 2010, Appendix B). In the area of I 46th Avenue SE the channel bottom is composed on sands and gravels, to well-graded gravel. Larger gravel, cobbles and occasional boulders are also present. In the relatively flat and low-gradient portions of May Valley in the area of I 48 th Avenue SE the hard channel is composed of silty-sand and sandy-silt. At the confluence with Long Marsh Creek the hard-channel bottom is composed of well-graded gravel. A variable layer of semi-liquid, organic rich mud (herein referred to as muck) is present within the stream channel behind constrictions in the channel (Figure 3). The muck was sampled 25 feet upstream of a private bridge at RM 4.6. A modified Loss on Ignition analysis (LOl) was performed on the sample and the organic content was approximately 28 percent. This is a very high percent organic material compared to King County streams (Burkey, personal communication). The exact source of this high organic content is unknown; however. the tributary stream channels within the project area do not contain the same muck material and the most likely sources are pastures, agricultural fields and grass/tree litter within and above the project limits. Sources of Stream Sediment Most of the major tributaries to May Valley enter May Creek upstream of I 64th or downstream of 146th , outside of the project area. Fromjust below I 48 th and I 64th four tributaries: an unnamed tributary (029Ia), Indian Meadows (0291). Long Marsh Creek (0289) and Greenes Creek (0288) enter May Creek. Small alluvial fans occurring at the base ofTrib. 0291a and Indian Meadows identifY where sediment is deposited at the valley floor. • A ditch carries Indian Meadows Creek to May Creek. The ditch carrying Indian Meadows has piles of sediment adjacent to the. ditch. These appear to be hand dug sediment piles removed from Indian Meadows Creek (Bauman, personal I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 7 communication). Finer sand and silt reached May Creek and the confluence with May Creek is clogged with silt and reed canarygrass (GeoEngineers, 2008). • Tributary 0291 a is shown on the 1872 map and before development ofthe valley flowing northwest parallel to May Creek, joining May Creek near the confluence with Indian Meadows. The stream now joins May Creek downstream of I 64th and is hydraulically controlled by a culvert under SR-900. Sediment is primarily deposited upstream from the culvert (Foster Wheeler). The creek lacks a defined channel above the confluence with May Creek. • Greenes Creek enters May Creek west of 148th Street and currently does not contribute significant sediment to the project area because Greenes Creek discharges to a wetland and the confluence with May Creek is choked with reed canarygrass. Table I: Two year flow for May Creek Tributaries in the Project Area (Foster Wheeler, 1995). Drainage Unnamed Trib. Indian Long Marsh Greenes 0291a Meadows 2 year flow in 23.8* 17 42 26 cfs *USGS StreamStats Estimate Within the project area, Long Marsh is one of the largest flow (Table I) and sediment inputs. The Long Marsh sediment deposits constrict flow and muck movement in May Creek. Long Marsh Creek joins May Creek south of May Valley Road near 150th Place NE . Aerial photography from 1936 shows the creek in a relatively straight channel. The current channel is on the order of two (2) feet wide and several inches in depth at winter low flow. The stream banks are approximately one foot in height, and the surrounding floodplain/fan surface is primarily planted in pasture grass with some recent native plantings. Evidence was found of gravel deposition throughout this reach. Discussions with earlier property tenants indicate that sediment deposition extended into the adjacent pastures following a January 2009 storm event. Long Marsh Creek deposits form an alluvial fan composed of cobble-to silt-sized particles and discharge silt, sand and gravel into May Creek. May Creek channel bottom elevations are higher near the confluence and this channel fill is a choke point for flow within the channel. During high-flow events, Long Marsh carries large gravel-sized sediment to May Creek. Before Long Marsh was straightened, the stream would have migrated across the alluvial fan as sediment was deposited in the stream channel. As noted in the previous section, the Long Marsh and Indian Meadows alluvial fans built out into May Valley and forced May Creek around the fan. Doug Chin February 9, 2011 Page 8 May Creek Channel Changes with Time Horizontal Boundaries Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited vegetation. Foster Wheeler measured the mean May Valley Creek channel width in 1995 as 20 to 25 feet, with wider sections up to 60 feet at RM 5.6 (Foster Wheeler, 1995). In March of 2002 a stream survey was conducted between I 64th Avenue SE and I 48th Avenue SE (O'Rollins, 2002) and measured the average channel width at ten to 14 feet. A stream survey was conducted in 2010 (Thompson and Bauman), and the average wetted width of habitat units was approximately 12.1 feet and the widest wetted width was 23 feet (surveyed reach RM 4.35 to RM 4.87). While no change in average width occurred from 2002 to 2010, there is a possible pattern of channel narrowing between the 1936 and 1995 and comparison between the 2002 and 2010 stream surveys. This is reflected in the available measurements; especially in areas dominated by reed canarygrass. The channel is still a relatively straight excavated ditch but grass, shrubs and trees have encroached into the channel. Survey data from 2002 and 2010 surveys are also available. Cross sections of May Creek are shown in Figure 4 (cross section locations are shown in Figure 5). Five cross sections were chosen to compare the stream channel at relatively fixed locations in the stream. Upstream of the road bridge at I 48th Avenue SE the channel is narrower and slightly shallower (Section B-B). Downstream ofthe bridge the channel is wider and more uniform in shape (Section A-A). The cross section at Long Marsh (Section D-D) shows the 2002 bank deposits (right bank) associated with excavating sediment from May Creek (private property owner activity) and the filled-in 2002 channel profile from Long Marsh Creek deposits. During the 2002 pilot excavation project in May Creek at the Long Marsh confluence, sediment was removed to approximately elevation 309. The left bank (looking upstream) has now filled in to 2002 elevations at the confluence but the rectangular channel shape is still present on the right bank. Upstream of Long Marsh Creek, the channel is approximately the same width but shallower. This may be due to where the survey staff was placed and the CAD program interpolating between points. Downstream of Long Marsh Creek the channel has narrowed. Survey locations varied slightly between center line, right bank or left bank and cross section elevations are approximate. I I I I I I I I I I. I II I I I I I I I I ;:: • 5 Q • , , "- Q ~ • , n • 3 Elevatim (ft) w w w w w ~8 5: ;:) if 9 g 14'a2008'~~ I"";;; <, r ' , 1 '"~ ~ ~ . I' 'I 4.265343 DO'Mlstream of Rodi. Weir .... , '--I 4.278770 DO'M'Istream of 146th BrilL ' "7 --:---.. 1 ~ 4.310823 KC Survey year 3)10 I -~, 4.3Z3418· t-< _.r· 1 . , .--n----------..--;-- ~ 1.4.353836 K'C Survey y~r aJ10~ '-~I'I_' . g l4.3e3391 KG Survey year 3)19, ' 1 \... I 4.387575 KG Survey year 2)10 I' . . 1 ,\. A.411003 ~ ~ . _ 4.426539 KG Survey year 2010 -\_ :::~~dJe~I·~~h·~J.--~1 _ _ ,~ 4.472884 KG Survey year .<DID (similar to OTA .. "'-..;, "+:- ~ '< " i& ~ m ~. ;;: " <C " o " ~ g :::::.K,C S"~~~: ~1' -- 4.532274 .'~ ~4.551f£lB .. -\:: Ie 1-' -~-~-j ~ ! ~ N A 0 0 0 4.575359 KG Survey year 2010 .4.600738 4.612613 4.640315 j " I ""l . ",,-l='"' I :-r /' ., I I ,/i '" '" s: 3' • m ~ " o ~ ",-· '" 4.700732 KG Survey yea, r all0 (Simil,ar to OTAK X.. , __ {.I ' '" / I _'Y."T l __ ~_-_'_----+ __ 4.749514 KG Survey year 2:110 (similar to OTAK XS . I k ~. to • (f> 3 " N g: 0 0 I j \. 4.788456 KG Survey year 2)10 (similar to otak xs " j I 4.828!"£O K,C Suryey year 2010 {similar to otak x .. 4.861266 4.887389 I... I I '! I § 1.4.912045 K,C su~ey year 2)10 {similar to ~tak xsid 014,937175 .. ,._.., I. _. _ ' , .4.949111 KC Survey year :<D10 (similar to otak xs , .. A.96B724_ ~ --/"".---t . ~.'- .4.988154 .1.. . 5.038988 otak xs 7'515 5.04 ~odtrid'Je u~tr63n: of Ca!asurd? pro~rty 1 I . -f-----1-· -- " " , \\, , " II , ' , I , ' , ; , - ?\ '-;.-\-, '\. ,z f5 ~ o o N '" ," (f> " ,z ~ '" " '" ~ o '.' '1--' 'd"1 ~ 1·5,09if03oiakxs?875~, __ . "1 \', ,C' _____ -'--_-'-__ 21 . , , ' '\ I 5, 13:1954 otak xs 8005 I , • • f \ -f~----'I \' 5 185707 o~ak xs 8315 :1-~--::-.: "r':" -!I ~I ;0 I =-a I " ", 3 , 51 !tli mien ~ I~ &. '(uo 1 0<: 'AjUno:) ;WI)! UI01,j) 010<: Ul SSOIDfJI'!l IllOUl!pOS~Jnl"J pUll ll0!lUAOI3 wonog IOllll",!:) ~UlMO,!S all/Old ~OOl:) AUI"J £ OlH~I,j 6 O~"d OIOZ '8 loqwOJOa ll!'!:) ~noa I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 20 II Page 10 Channel Bottom Elevation Channel elevation surveys were conducted in 1965, 1979, 1993,2002 and 2010 (Data is located in Appendix C). A profile of May Creek channel from just below 14Sth Avenue . SE to approximately 1,300 feet upstream of the confluence with Long Marsh Creek as shown in Figure 5. The figure compares the 2002 and 2010 survey profiles and gives spot elevations at the 14Sth Avenue road bridge and at the horse-crossing bridge on parcel 0223059091,15019 SE May Valley Road from 1965, 1979, and 1993. Upstream of Long Marsh, between 2002 and 20 I 0 the hard channel bottom is a foot lower in some areas and a foot to two feet higher in others. At the horse bridge the elevation has varied from 307 feet to 311 feet associated with sediment deposition from Long Marsh Creek. From station 11 +00 to S+OO at 14S'h A venue, the channel profile has flattened and the channel bottom has shall owed approximately three feet. This area coincides with thick areas of reed canarygrass. Between 1965 and 2010, the 14Sth Avenue road bridge channel profile has stayed relatively consistent at 307 to 30S feet. It appears from the elevation differences that where the muck and vegetation builds up, the channel bottom has also been aggrading. Changes in the bottom elevation should be considered approximate, perhaps within a foot of elevation change. Survey elevations have not been taken at the exact same locations and stationing is different between projects. Stream profiles in 2002 and 2010 (Figures 4 and 5) show thicker areas of muck build up behind higher elevations in the channel. Up to four feet of muck was measured above the Long Marsh Creek confluence in 2002 and three feet in 2010. Stream and elevation survey data indicates that soft muck present in the channel varies in thickness by'location and with time. The muck thickness is variable and transitory, building up in the channel until higher flows in May Creek are able to move the sediment downstream. , Muck and fine sediment is moved downstream by May Creek within the valley as bedload and suspended sediment. However, the valley and May Creek above May Valley is not the main source of sediment to Lake Washington. The May Creek Current and Future Conditions report (1995) identified the major source of sediment to the May Creek delta in Lake Washington as the May Creek canyon and eroding channels oftributaries that enter the mainstem downstream of May Valley. I I I I I I I I I I I I I I I I I I I 320. 1'320 2010 CHANNEL '2002 :CHANNEL 3101~~~~\llr---------1310 300,100 -to 6 5'0 (\300 1 0 SECTION A-A STA. 7+00 DOWNSTREAM OF 148TH ST (I\ Nl'3 ""-..-/ 3201 nnn') 1320 3101.·· :2010 :CHANNEL r- .f./ .. .. "310 3':.0,1 00 -to b ~O 1 ~'600 SECTION 8-8 STA. 8+00 UPSTREAM OF 148TH ST N15 f2\ ""-..-/ MAY CREEK CHANNEL RESTORATION FIG. @] CROSS SECTIONS 3201 1320 3101 .. 3001 -100 -to 2010 CHANNEL .?002 CHANNa,- ~~ ...... 6 ~o SECTION C-C STA. 15+00 DOWNSTREAM OF LONG MARSH CREEK NTS "310 <1 300 1 0 ffi .........., 320r~~------o---~=;~-r----------r=~mo----~ c:::::= 2010 1 ;:--2002 1 320 CHANNaL / : CHANNEL ~~ r---. 310" -. "310 3'!.~100 -to b 510 ,~'600 SECTION D-D STA. 16+00 LONG MARSH CREEK NTS f4\ .........., 320, 1320 2002 CHANNEL ------- 3101. . 3001 -100 -to 6 5'0 SECTION E-E STA. 17+00 UPSTREAM OF LONG MARSH CREEK NTS NOlE' ALL CROSS SECTIONS ARE CREATED LEFT TO RIGHT LOOKING UPSTREAM . "310 <1300 1 0 f5\ .........., I I I I ;. I I I I' I I I. 335 r-~--~--~--~----~--~--~--~--~--~--~--~--__ --__ --__ ---'1335 I 330 I 325 330 325 I 320 I 315 • 310 Ii::: 295 320 ~ ..• 6Z~P~~~K~'f~'6~UNE • L~~~NEL £~~INEL.~. • ••• '310 ·····i.C?·O : Z(7?</(.(?7??7/D.(71/~.: 305 315 3DD 295 I I 290 UTVU I 9+00 10+00 1 1 +00 290 I I DETAiL 1 SCAlE: 1"=40' I MAY CREEK CHANNEL RESTORATION FIG.~PROFILES 3351' -. ,335 330 325 320 315 31 0 F:'".;,.-,-~ ,""",~~ 305 300 295 16+00 :~APPROX. ELEVATION: : . r 201G . . ( __ OF:C~ ATFLOWUNE .. .L __ . C><AtL · 17+00 18+00 19+00 20+00 DETAiL 2 SCALE: r =40' 330 325 320 2002 . , CHANNEl· 315 310 -.-~-305 300 295 21+00 22+00 23+00 [ •• ---. -i/ ~ 0 ~ ro I~ SCALE IN FE£T I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 13 Findings: Project Features and Estimated Results Pre-project May Creek Sediment Sources and Channel Behavior above the May Creek Ravine: Based on field reviews of the project area, stream report (King County, 2010), a literature review of past reports on the May Creek basin, and a review of aerial photographs a qualitative estimate of sediment sources has been developed. Sediment entering the project area comes from: • Upstream May Creek (east of I 64 th ). Most of the major tributaries enter May Creek above the project and therefore will be a contributor to suspended sediment in the Creek. Six beaver dams are present or have been active in the past above the project area; two below 164th and four upstream of the project. • Long Marsh Creek is a contributor to channel fill by sand; gravel and small cobbles. The larger materials are able to reach May Creek during high flows due to the straight channel, slope and past channel maintenance by property owners. • Indian Meadows Creek is a minor drainage that is partially ditched through a pasture that reaches May Creek and contributes sediment toMay Creek. • Tributaries (029IA, 0291) contribute minor but unknown amounts of fine sediment. • Stormwater runoff and pasture flooding contributes an estimated .2 to .8 metric tons of organic material and sediment to the stream. The May Creek channel is essentially a ditch, excavated in a historic wetland system prior to 1930. The gradient in May Valley is very low and the creek is only able to transport clay to sand sized sediment. • The May Creek channel stores organic muck/sediment from pasture~ behind relatively high spots in the channel bottom and releases it downstream to the ravine during higher flows. Muck then builds up again as flows recede and during rain events. Some ofthe muck contributes to aggrading the channel bottom as it is trapped and entrained by vegetation. The May Creek project proposes a number of features to reduce sedimentation to May Creek and channel filling. The 70% design plans include: • removal and control ofreed canarygrass (Phalaris arundinacea); • native plant buffers along the banks; • reducing overbank flooding; • selected removal of vegetation from the channel downstream of I 48th A venue SE; • excavated alcoves adjacent to the channel downstream of 148'h Avenue SE, • a sediment management design for Long Marsh Creek, the primary source of sediment and channel constriction in the project area. These features are expected to produce the following results: • Removal and control of reed canarygrass will slow channel narrowing and infilling due to growth during spring and summer during low flows. Doug Chin February 9, 20 II Page 14 • Adding plant buffers on either side of May Creek will shade the banks where reed canarygrass is present and help control grass growth and encroachment. • Reducing over-bank flooding of pastures will reduce the amount of sediment and organic material being carried to the creek by an estimated .2 to 0.8 metric tons per year. • Improved channel hydraulic efficiency will improve and move fine sediment and organic material that reaches the creek downstream, reducing the amount of sediment trapped in reed canarygrass above I 48 th Avenue SE. • The proposed alcove excavation and planting areas west of I 48 th Avenue SE will allow the creek to overflow into the alcoves during higher flows; this will slow the current velocities and minor amounts of sediment will drop out of suspension, but the amount of deposition is unknown. • The May Creek channel is likely to be both a depositional area and a source of suspended sediment during higher flows. Soft muck in the stream bottom above the confluence with Long Marsh Creek is a combination of organic material from pasture runoff with mineral sediment. The muck builds up in the channel after rain storms and floods and is moved downstream during higher flows. Reducing flooding within the project area will help reduce the build up of muck in the channel. • A mitigation project in Long Marsh Creek will intercept gravel and large sand-size sediment reaching May Creek. • Bank stabilization with jute netting and seeding will reduce erosion and sediment input to May Creek after excavation. Estimated Changes in Sediment Transport and Channel Dimensions after Drainage Improvement Project: The proposed project elements and existing conditions were evaluated for how sediment would ente~ and move within the project area. Ifno change in behavior was expected, the conditions were assumed to remain the same and are listed below as "constant". I f the project element was expected to modify sediment behavior by qualitatively reducing the amount of sediment reaching May Creek, a reduction is noted in the bulleted list below. During construction, temporary increases in sediment are possible and this is noted. • Constant Upstream May Creek (east of I 64th ). Most of the major tributaries enter May Creek above the project and therefore will continue to be a contributor to fine sediment in the Creek. Beaver dams will hold back sediment and periodically release it when breached. • Constant Tributaries (029IA, 0291 and Indian Meadows Creek) contribute unknown amounts of fine sediment. These are expected to be minor. • Reduction Small proposed mitigation alcoves downstream from 148 th will allow sediment to deposit at higher flows. • Reduction Long Marsh Creek mitigation project will minimize course sediment reaching May Creek and channel infilling. • Reduction Reduced pasture flooding will reduce the organic material and sediment discharged to the stream, estimated at .2 to .8 metric tons. I I I I I I I I Ii I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 15 • • • Reduction Reduce channel narrowing by controlling reed canarygrass along the banks by establishing a buffer of plants on either side of the channel and shading the banks. Temporary Increase Channel excavation will temporarily expose "raw" bank and channel sediments to the channel. Jute matting and bank planting will control erosion but minor erosion within the channel may occur as the channel stabilizes. Change in fine sediment movement Fine mineral and organic sediments that reach May Creek and are now stored in the stream channel or trapped by grass during low flows will move downstream during lower flows. Fine sediment and organic material currently stored in the channel and moved downstream during high-flow events, will move downstream at a constant rate rather than episodic rate. The overall estimate is a net reduction in fine sediment and organic ma!erial reaching May Creek within the project area. Long Marsh Creek mitigation, the mitigation alcoves, reduced flooding, and reed canarygrass control are project features that decrease sediment contributions to May Creek in the project area. Controlling willow and reed canarygrass will control channel narrowing. Responses to Questions on Project Performance Question I: Will the project change sediment delivery downstream to May Creek? Response: The May Creek Current and Future Conditions report (Foster Wheeler, 1995) identified the major sources of sediment to May Creek as coming from the ravine and tributaries below May Valley. The hydraulic analysis (King County, 201 Oa) shows that changes in flow velocity below 143rd Avenue SE are negligible. Sediment movement is controlled by flow. Therefore, the same size sediments would be moved within the May Creek system. Muck sediments are currently stored behind topographic highs in the stream channel and are moved downstream in pulses during high flow events. In general fine sediment that does enter the creek as bedload or suspended sediment will move downstream due to improved channel efficiency rather than being stored in the creek channel above 148th, incorporated into the banks and moving though during large flow events. However, some fine sediment or muck that does enter the creek will continue to be stored behind topographic highs in the channel or in topographic lows above and below 148 th Avenue. We estimate the project-related reductions in sediment delivered to the creek primarily from reduced overbank flooding, will reduce the total fine sediment and organic muck in the stream. Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? Response: We estimate that there will be an overall reduction in sediment contributions to May Creek within the project area. The stream channel bottom elevation is relatively stable, except where Long Marsh Creek discharges to May Creek and where reed cannarygrass and muck aggrades the channel. Reducing sediment and organic matter input to the channel from Long Marsh Creek and the pastures and removing reed Doug Chin February 9, 2011 Page 16 canarygrass will slow narrowing of the channel. Active monitoring and buffer-planting management along the creek banks will take place for ten years to allow establishment of native vegetation buffers. The larger channel can be expected to last beyond ten years. This assessment is based on qualitative analysis with available information. Quantitative sediment estimates are not available. I I Ii I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 17 References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. Booth, D.B., Haugerud, R.A., and Sacket, 1. Geologic map of King County, Washington: scale I: I 00,000. Bretz, J. Harlen, 1913, Glaciation ofPuget Sound Region, Bulletin 8, Washington Geological Survey, 244p. Burton, G. Allen, and Robert Pitt. 2002. Stormwater Effects Handbook: A Toolbox for Watershed Managers, Scientists, and Engineers. Lewis Publishers, Boca Raton, Florida. hltp:llwww.epa.gov/ednnrmrllpublications/books/handbook/toc.pdf Foster Wheeler,.1995. See King County, 1995 below. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. Hart Crowser, 2009, Final Site Investigation Report, Loon Lake, Washington, prepared for the Washington Department of Natural Resources, 117 p. Access online September 20 I 0 at: http://www.dnr.wa.govfPublicationsfaqr loon lake tinal invest report. pdf Homer, Richard R., Joseph J. Skupien, Eric H. Livingston, and H. Earl Shaver. 1994. Fundamentals of Urban Runoff Management: Technical and Institutional Issues. Prepared by the Terrene Institute, Washington, DC, in cooperation with the U.S. Environmental Protection Agency. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. April 2001, May Creek Basin Action Plan. King County Department of Natural Resources, Water and Land Resources Division. King County 2007. Water Quality Statistical and Pollutant Loadings Analysis -Green- Duwamish Watershed Water Quality Assessment. Prepared by Herrera Doug Chin February 9, 20 II Page 18 Environmental Consultants, Inc. http://grccn.kingcolinty.gov/WLR/Waten·cs/StreamsData/reports/green- dllwamish-Ioading-report.aspx King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. 20 lOb. King County GIS Center LIDAR, Topography, Geology, and Stream Location Layers, viewed with ARCGIS http://www5.kingcollnty.gov/gisdataportal/ King County. 2010c. Particle Size Evaluation of May Creek Water Channel Soils, Job Number IB1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, W A. King County. 2010d. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, W A. . King County. 201Oe. May Creek Drainage Improvement Project 70% Design Progress Plans dated 10-22-10. King County. 2010f. Baseline Stream Conditions May CreekDrainage Improvements, CIP#9AI205. NCRS 1993. Soil Survey Division Staff. Soil survey manual. Soil Conservation Service. u.s. Department of Agriculture Handbook 18. http:// so i I s. usda. gov Itechni ca IImanua II Yount, J.C. and Glower, H.D., 1991 Bedrock Geologic Map of the Seattle 30' by 60' Quadrangle, Washington: U.S. Geological Survey, Open-File Report OF-91-147, scale I: 1000000. I II I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin January 10, 2011 Page 19 Appendix A Aerial Photos and Historic Maps I I I I I I I I I I I I I I I I I I I .... ~ , ~ , .. Doug Chin February 9, 20 I I Page 20 May Creek Drainage Project, May Valley Lldar Image 2002 7V,CIIl5OCD 79.000I58 ,00Q37,OOO10,1XJO F-.t N + tQ KIng County I I I I I I I I I I I I I I I I I I I May Creek Drainage Project, May Valley 1936 Aerial Photo 79 .1D)5O(D 79.000158.00Q37 .00016.000 F •• , -- -- - - N + ttl King County .... --'-- I"" 1 . : .. ,." " 1 \.: . ' ... i " •.... \ ' , I " I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 23 Appendix B Channel Bottom Sediment Sample Analysis I I I I I I I I I I I I I I I I I I I ti Kinlc:. It) Road Services Division Materials Laboratory Department of Transportation RSD-TR-0100 155 Monroe Avenue Northeast, Building 0 Renton, WA 98056-4199 www.metrokc.gov/roads May 11, 2010 TO: VIA: Jeff Burkey, Hydrologist, King County Department of Natural Resources and Parks, Water and Land Resources Division . Ala~ Materials Engineer, King County Department of Transpo tion, Road Services Division, Materials Laboratory :;::---;-;<i'i''":>----FM: Timot Hyden, Engineer III, King County Department of Transportation, Road ices Division, Materials Laboratory RE: Particle Size Evaluation of May Creek Water Channel Soils Job Number 1B1205. Task MTR The King County Materials Laboratory (KCML) obtained soil samples and performed field evaluations to determine the distribution of soil and rock particle sizes in the water channel along a section of May Creek. Areas from which samples were obtained or evaluations performed are summarized as follows: Area 1: Colasurdo Property (Red Barn) Sample KC-10-429: The sample was obtained using chest waders and a shovel from the north side of the water channel approximately 75 feet downstream from the bridge. The water was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately 0" to 3" below the bottom of the channel. At the sample location, the bottom of the channel appeared to be exposed and was not covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is sandy silt (ML). Sample KC-10-430: The sample was obtained from the same location and using the same methods as KC-10-429, except at a depth of approximately 3" to 6" below the bottom of the channel. At approximately 3" there was a transition in the soil and it was visually classified as a mixture of the silt from KC-10-429 with gray, fine silty sand. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is silty sand (SM). Report of May Creek Sampling & Testing Particle Size Evaluation of May Creek Water Channel Soils Job Number 161205, Task MTR =-----,,-;-:-=:-:-::,--------, Gambini 2010 Area 2: McFarla d Property (Yellow House and Out Buildings) Page 2 of 4 5/11/2010 Sample KC-10-426: The sample was obtained at the confluence of a small unnamed stream and May Creek, approximately 30 feet upstream from the bridge. The water depth was approximately 12 inches with moderate flow and the surface of the water channel consisted of Clean sand and gravels. This sample represents materials from approximately 0" to 6" below the bottom of the channel. No significant vegetation was noted at the sampling location. A gradation test using conventional screening methods was performed and the USCS classification for this material is well graded gravel (GW). Sample KC-10-431: The sample was obtained using chest waders and a shovel from the south side of the water channel, approximately 100 foot upstream from the bridge. The water depth was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately 0" to 6" below the bottom of the channel. At the sample location, the bottom of the channel did not appear to be covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is sandy silt (ML). Area 3: 14Sth Avenue SE Sample KC-10-432: The sample was obtained using chest waders and a shovel from the north side of the water channel approximately 75 feet downstream from the bridge. The water was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately 0" to 6" below the bottom of the channel. At the sample location, the bottom of the channel appeared to be exposed and was not covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is silty sand (SM). Area 4: 146th Avenue SE Sample KC-10-427: The sample was obtained using hip waders and a shovel from the thalweg area of the creek channel, immediately adjacent to the upstream side of the bridge. The water was approximately 2 feet deep, flowing moderately fast and the surface of the water channel consisted of sands and gravels. Some of the fine sands were washed off the shovel while sampling due to the moderately fast water flows. It is roughly estimated that 75% percent of the bottom of the water channel surface area consists of sand and small gravel. Larger gravel and cobbles with a maximum particle size of about 4 inches make up the remaining approximate 25% of the channel bottom surface area. A gradation test using conventional screening methods was performed and the USCS classification for this material is well graded gravel with sand (GW). The mid-stream bridge pier appears to have 12" to 18" rip rap placed as armoring on the upstream nose of the footing/pile cap. Report of May Creek Sampling & Testing I I I I I I I I I II I I I I I I I I I I I I I I I I I I I I I I I I I I I I Particle Size Evaluation of May Creek Water Channel Soils Job Number 161205, Task MTR Page 3 of 4 5/11/2010 Sample KC-10-428: The sample was obtained using hip waders and a shovel from the thalweg area of the creek channel, immediately adjacent to the downstream side of the bridge. The water was approximately 2 feet deep, flowing moderately fast and the surface of the water channel consisted of sands and gravels. Some of the fine sands were washed off the shovel while sampling due to the moderately fast water flows. It is roughly estimated that 60% percent of the bottom of the water channel surface area consists of sand and small gravel. A gradation test using_ conventional screening methods was performed on material finer than a 3" sieve and the USCS classification for this material is well graded gravel (GW). Larger gravel, cobbles and occasional boulders with a maximum particle size of about 12 inches make up the remaining approximate 40% of the channel bottom surface area. The sides of the channel directly adjacent to the abutment are armored with broken pieces of concrete. A few pieces of broken concrete were observed in the thalweg of the creek channel. Directly downstream from the concrete armoring the sides of the water channel are undercut. An estimate of the overall creek bottom material gradation was obtained in the vicinity of the thalweg. The evaluation of material gradation was determined by reaching into the water and randomly touching a location on the creek bed. Material encountered at the bottom of the creek bed larger than 1 inch was removed from the water and measured. Materials finer than 1 inch were visually assessed as being similar to materials from sample KC-10-428 that were also finer than 1 inch. The particular sizes of material found on the creek bed were recorded and are shown in Table 1. The dimensions shown in Table 1 are approximately equal to a square mesh sieve that the materials would pass. - -TABLE 1 Sieve Size *Count Sieve Size Count -1" Fines 5 5" 2 1W 5 6" . 1 -. 2" 5 7" 1 3" 5 12" 1 4" 0 • Indicates number of times the referenced size of material was encountered. Area 5: 143rd Avenue SE Samples of fine materials for laboratory gradation testing were not obtained from the bottom of the creek channel. The water was approximately 18 inches deep and flowing fast. There was very little fine (sand size and smaller) material present on the creek bed surface and representative samples could not be obtained with a shovel or similar tool due to the fast flowing water. An estimate of the overall creek bottom material gradation was obtained in the vicinity of the thalweg. The estimate was performed directly adjacent to, and on the upstream and downstream sides of the bridge. The evaluation of material sizes was Report of May Creek Sampling & Testing Particle Size Evaluation of May Creek Water Channel Soils Job Number 161205, Task MTR Page 4 of4 5/11/2010 determined as previously described for Area 4: 146th Avenue SE, Sample KC-10- 428. Most all materials larger than about 3 inches had sharp edges and a few pieces of broken brick were encountered. Material size counts for the upstream and downstream sides of the bridge are shown below as Table 2 and Table 3, respectively. TABLE 2 Sieve Size Count Sieve Size Count -1 1/2" Fines 2 8" 2 2" 2 9" 0 3" 3 10" 0 4" 6 10" -12" 0 5" 5 12" -15" 2 6" 3 15" -18" 0 7" 1 TABLE 3 Sieve Size Count Sieve Size Count -1 1/2" Fines 1 8" 3 2" 0 9" 0 3" 1 10" 0 4" 2 10" -12" 1 5" 4 12" -15" 1 6" 8 15" -18" 2 7" 4 We appreciate the opportunity to have been of service and trust this report addresses your current needs. Please call me at 206-391-0552 or Alan Corwin at 206-296-7711, should you have questions or we can be of further assistance. Attachments: Figure 1 -Laboratory Test Results KC-10-426 through KC-10-428 Figure 2 -Laboratory Test Results KC-10-429 through KC-10-431 Figure 3 -Laboratory Test Results KC-10-432 Report of May Creek Sampling & Testing I I I •• - I· I •• I I I I I I ,I I I I I -' - - - ----, ---' -•. --- - - - '" IW ,2 u:: !z w ~ W Il. I I 1°1 Ie; ~I Particle Size Distribution Report J u.s, SIEVE" OPENING IN INCHES U.S.,.STANDARD SIEVE NUMSEB:S HYDROMETER . _ 1 ~·in. %In..., 318 in, "#":40 & in, -, ... :: ,lJ.:},';':' 2 in; . 1 in. Yz in: #4 #10 #2Q#30 ·#40 #GO #100 #200 1001 'j I l' I I' . 'Ii : "ll 'I '1" ! I 1:1 1" 'I ,. ,:: 1:1 , i: j : f 1 1 '. ~ l' 1 \ 1 ') ill l j • , , ,', ' 1 I 'I ' : ~ 'j I ,'f ' I ! " ~ , , , I I 1 " ' , I !" , 1.., , , 1_101-: , ,1 , 90 --.--J-T'i : ~-;-~-~II~:-:-:--:---, :;~:~--~:~~: HI • I . . ; i .; I I :::=I=!~ __ j_'-_--_--i-llff' -1-~-:=~~~~i-;"!+!:'-~;-----;----==;:I';~!~~;~:~~--':-'=~=:;~:~;~:~~~;~~-~----=~i:-~:I.'-·!'-----:'·'''''---_+_,~_ ; I i "...LI T ' ' , , I . I" I '..L ' , , " i' , , , I -' I ' i ! ' L' I J . 601-'I~i-' -. ,--, -, 11-' TI , --'-'--,-1 1-:,"---" ---,-------, , ,-1---, -.• ---{----;--j-. -i--, -, ,--' r,',-I--, ,_. --,----!---,--. j !, f I! ! !I II: I f J I II Ll " 'I I , I.J . , ' I' ! ". ,', J I ' , , . I -o'l-i t -' ri-"1---'. .-. 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Sample # I ·o"plhlElev, Date Samp~1 uses I Material Description l NM% I LL I PL I [01 'KC,IO-429 0", 3" 4127/10 . ML , Sandy silt -':-----r NV r N[J iKC-I0-430 I 3:',6" 4127110 I SM I SilIV sand ! I -NV ! Np· 10 ___ 1_ fAr i'KG-l 0-43 l' 0",6" r-4ii7flO' ML i Sand\' silt INV!NP L " KING COUNTY o Colossurdo 75' downstreanl from bridge. center of channel "Clieni K;llg Go'un!J> o Colosurdo 75' downstream from bridge, 'N third of channel ,Project May Creek Stream Bottom Evaluation " McFarland 100' upstream from bridge, N third of channel --! I Figur~_. MATERIALS LABORATORY ----"-"--JJ II Project No, IBI,205 , 2 -I , --_ .•. _"",.=-""",,," ----_ .... " ..... ---._". 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NV r NP II Client King County KING COUNTY 1° 148th, 75' downstream from bridge, N third ofehannel !lfrojecLMa,r Creek Stream Bottom Evaluation PrQj~ct No. IBI20S Tf'ig~re 3 MATERIALS LABORATORY , ...... .;:. --.-'"~'"' ._ ....... .'~i!-t .. ~---.~. '-'''' I I I I I I I I I I I I I I I I I I I ~ King County Department of Transportation Road Services Oivision Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov DATE: February 8,2011 TO: File FROM: Julia Tumey, LG 2493 King County Road Services Division Environm ental Unit RE: May Creek Organic Sediment Sample Results Sample Date: October 8, 20 I O. MEMO Sample Location: The sample was obtained from the May Creek Channel approximately 25 feet upstream from the foot bridge crossing the May Creek Channel (Gam bini and Tse~ay properties 15019 SE May Valley Road Parcel number 0223059091 and 10008 148 Ave SE Parcel 0223059075.) Sample Methodology: The sample was taken using a small three cup plastic container. The sample was scooped from the soft sediment layer on the bottom of the channel. Several passes were made in the sediment to obtain a full container and representative sample. Free water was decanted from the top ofthe container and the soft muck sample was poured into a wide mouth one quart plastic jar with a screw top. The jar was labeled and taken back to the KCRSD office at 20 I S Jackson Street, Seattle W A. The sample was stored in the sample refrigerator in a locked storage room from Oct. 9-11. The sample was transported to the King County Materials Laboratory (KCML) on October 12th. Sample Analysis: The King County Materials Laboratory (KCML) performed testing to determine the percent of organic material. The sample was designated as "May Creek Sediment Muck';" Gambini Prop., 25' Upstream from Bridge". The sample was initially placed in an oven and dried at a temperature of 1400 Fahrenheit to a constant weight to determine moisture content. The dried material was weighed and placed in an oven at 4400 Fahrenheit until reaching a constant weight to determine the organic material content based upon loss on ignition. Organic matter that had not ignited at a temperature of 4400 Fahrenheit was observed in the sample. The remaining sample was weighed and placed in an oven at 1000 0 until reaching a constant weight to ignite additional organic material. r May Creek Organic Sediment Sample Results Page 2 Sample Results: • Initial Moisture Content of Material Dried at 140° Fahrenheit: 498% (140° Fahrenheit Oven) • Total Loss on Ignition (Organic Content) of Material Initially Dried at 140° Fahrenheit: 15.3% (440° Fahrenheit Oven) • Total Loss on Ignition (Organic Content) of Material Initially Dried at 140° Fahrenheit: 28.2% (1000° Fahrenheit Oven) • . The moisture content percent is weight of water lost compared to the dry weight of the sediment sample. • The total percent organic material in the sample is 28.2%. • The organic material content percent is weight loss during thetest compared to the dry weight of the sediment sample. • The 1000 degree test temperature may cause water loss in the clay mineral structure and this would contribute to a high reading for organics. The test was run until the sample weight was consistent. • 28.2% represents an approximate organic content but may be a slightly high result due to test conditions. References King County 20 lOa. Particle Size Evaluation of May Creek Water Channel Soils, Job Number 1B1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, W A. King County 2010b. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, WA. NCRS 1993. Soil Survey Division Staff. Soil Survey Manual. Soil Conservation Service. u.s. Department of Agriculture Handbook 18. http://soils. usda. gov /tech nical/man ual/ Oliver, H. et.a1.2001. Loss on Ignition as a Method For Estimating Organic and Carbonate Content in Sediments: Reproducibility and Comparability of Results, Journal of Paleolimnology 25: 101-110,2001 . I 'I, I I: I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 33 Appendix C May Creek Channel Survey Elevations 1965, 1979, 1993,2002 and 2010. -------- -, - - - ------------ - - - - May Creek Profiles Comparison 1993 Stream Profile Cross-sections SUlVeyed 411993 for HEC-2 Model for Max..Creek Basin Plan River Min Ch EI Length Cum Chnl Station (ft) Chnl (ft)' Length (ft) 2756 298,3 10 10 3061 302,5 305 315 3571 r-~3,3 510 825 359"1 303,2 20 845 3596,5 146th Ave Bridge 3602 303.2 0,1 845 3622 304.4 20 865 4047 304.3 425 1290 4397 303.2 350 1640 4507 304.3 110 1750 4518.5 148th Ave Bridge 4530 304.3 0.1 1750 4580 304.4 50 1800 4630 305.3 50 1850 4825 305.3 195 2045 5310.5 Red Bam Pvt. Bridge 5316 306.9 0.1 2045 5366 306.4 50 2095 6041 305.8 695 2790 6646 306.8 605 3395 6652 Colasurdo East Pvt. Bridge 6658 3072 0.1 6708 306.8 50 7123 306 455 7618 308.4 495 7628 308,1 10 7634 Private Bridge 7640 308.1 0.1 7650 308.41 10 StreamProfile _ comp.xls tdp 11/20/2001 I3lYss- 3395 3445 3900 4395 4405 4406 4416 1965 Harstad Study Drainage Comerehenslve Plan Referenced by 1981 May Creek Basin Plan Techlncal Appendix Seg Chnl Chnl Length # Elevation (ft) 930 300.4 20 929 304 895 928 304.1 930 927 304.1 1835 926 304.5 1860 1--. 924 305.9 -~ 1--- 1-- L. ._-L ______ . __ 1979 Stream Profile FEMA Data for May Creek May Creek Basin Plan Technlca'--Flood Profiel for May Cree!! ___ .. Appendix, Figure C-1 ----r-.-.-- Sta Chnl Chnl Length River Chnl Chnl Length 10 Elevation (ft) Station Elevation I jft) 1 299.3 30 ~=t---~ --- ---------.-- 1------c=-== --2 . 304,9 842 AG 303.1 850 2A 304.2 1060 --,,- .3 303,5 1755 AI 304.3 1748 304 2055 AK 306.9 2540 - 305.4 3425 AM 307 3913 3A 306B 3690 - - 308 4455 AO 308 4969 _. --_. 1 of 2 May Creek Profiles Comparison 1993 Stream Profile Cross-sections Sutveyed 411993 for HEC-2 Model for May Creek Basin Plan River MinCh EI Length Cum Chnl Station (ftl Chnl (ft) Length (ft) 8835 307.1 1185 5601 9985 310.4 1150 6751 10935 310.1 950 7701 11435 313.3 500 8201 11735 313.5 300 8501 11835 313.5 100 8601 11849 164th Ave Bridge 11863 313.5 0.1 8601 11963 314.2 50 8651 12323 313.3 410 9061 13143 315 820 9881 13893 316.4 750 10631 14608 316.5 715 11346 15488 318.5 880 12226 16148 318.7 660 12886 16953 319.8 805 13691 17563 321.6 610 14301 17573 322 10 14311 17602 Renton-Issaq. Road Bridge 17631 322 0.1 14311 17641 321.5 10 14321 17741 321.5 100 14421 18026 326.1 285 14706 18216 327.7 190 14896 ·18316 327.8 100 14996 18323 SE May Valley Road Bridge 18329 327.81 SlreamProfile_comp.xls Idp 11/20/2001 0.1 14996 1965 Harstad Study 1979 Stream Profile FEMA Data for May Creek Drainage Comprehensive Plan May Creek Basin Plan Technical Flood Profiel for May Creek Referenced by 1981 May Creek Appendix, Figure C-1 Basin Plan Techincal Appendix Sta Chnl Chnl Length Sta Chnl Chnl Length River Chnl Chnl Length 10 Elevation (ftl 10 Elevation (ft) Station Elevation (ftl 4A 306.1 5900 5 310.7 7030 1 921 313.5 9200 6 314 '8670 AS 314.5 8290 7 317 11340 1 8 317.1 12680 8A 319.9 13060 918 320.3 14955 9 321.5 14380 BA 322 14045 915 327.8 15735 10 328 15030 BC 328 14784 20f2 ------------------- I I qq.~ rf!-op/_~ I - I CAD Values for drawing profile Min Ch EI Length Chnl Ely Distance Cum Length Chnl (ft) (ft) Ely. Difference Diy. By 10 Diy. By 100 (ttl I 298.' 10 0.10 10 302.5 305 -4.2 of!J.4~ 3.05 315 303.3. 530 -0.8 Al.08 ·5.30 845 304.3 445 -1 ..a. 1 4.45 1290 I 303.2 350 1.1 ( ~6:r1) 3.50 1640 _. 304.3 160 -1.1 ..0.11 1.60 1800,- -305.3 245 -1 ~.1 2.45 2045 I 306.4 50 -1.1 1,(l.11 0.50 2095 305.8 695 0.6 ,~6:O~ 6.95 2790 ~---- 306.8 655 -1 1/00.1 6.55 3445 I 306 455 0.8 ~.·Jl:li8·· 4.55 3900 308.4 515 -2.4 ...0.24 5.15 4415 307.1 1185 1.3 c':::::'::fi~; 11.85 5600 310.4 2100 -3.3 '0.33 21.00 7700 I 313.3 900 -2.9 JlO.29 9.00 8600 314.2 50 -0.9 Al.09 0.50 8650 313.3 410 0.9 _~O.o9;> 4.10 9060 I 315 820 -1.7 rO·17 8.20 9880 31.6.4 1465 -1.4 ..0.14 14.65 11345 318.5 1540 -2.1 10.21 15.40 12885 I 319.8 805 -1.3 ~.13 8.05 13690 321.6 610 -1.8 .0.18 6.10 14300 322 10 -0.4 Al.04 0.10 14310 I 321.5 110 0.5 .::::!!Jl.5·. 1.10 14420 326.1 285 -4.6 ,.0.46 2.85 14705 327.7 290 -1.6 .. 0.16 2.90 14995 328.5 100 -0.8 ~.08 1.00 15095 I 329.2 305 -0.7 ~.07 3.05 15400 I I I I I I I jqq3 c;rr5Yi pPof4 I CAD Values for drawing profile I Min Ch EI Length Chnl Cum Length Chnl Elv Distance (ft) (tt) (tt) Elv. Difference Div. By 10 Div. By 100 298.3 10 10 0.10 302.5 305 315 -4.2 ,--._-:9-,.~2 .:J c3,15'_) I 303.3 825 O~ 1 0.01 8.45 I Bridge -1.2 -0.12 8.65 304.3 0.1 0.01 12.90 I 30~2. .. 350 1.1 0.11 16.40 I~A\k IllCtD&" ~ 304.3 110 -1.1 -0.11 17.50 :?tif P '~J.<t-Bridge . ~ :; I I -" QED 50 -0.1 -0.01 18.00 395.3 @Uf) -0.9 -0.09 18.50 I 305.3 2045.2 0 0 20.45 Bridge 396.9 9.1 ;1946.6 I 306.4 50 2095.3 0.5 0.05 20.95 305.8 695 2790.3 0.6 0.06 27.90 306.8 605 3395.3 -1 -0.1 33.95 I Bridge < 397.2 9.1 3395.4 306.8 50 3445.4 0.4 0.04 34.45 .306 455 3900.4 0.8 0.08 39.00 I 308.4 dP ')0\ 4395.4 -2.4 -0.24 43.95 698.1 1196.4 0.3 0.03 44.05 Bridge I 388.1 Q,1 44055 308.4 10 4415.5 -0.3 -0.03 44.16 307.1 1185 5600.5 1.3 0.13 56.01 I 310.4 1150 6750.5 -3.3 -0.33 67.51 310.1 950 7700.5 0.3 0.03 77.01 313.3 8200.5 -3.2 -0.32 82.01 313.5 8500.5 -0.2 -0.02 85.01 I 0 0 86.01 Bridge jf~ .( -7 0 0 86.51 I 0.9 0.09 90.61 (I!-" )' -1.7 -0.17 98.81 I -1.4 -0.14 106.31 -0.1 -0.01 113.46 318.5 12225.6 -2 -0.2 122.26 I -0.2 -0.02 128.86 319.8 -1.1 -0.11 136.91 321.6 -1.8 -0.18 143.01 322 -0.4 -0.04 143.11 I Bridge I It q'l I rlO I I I I I I I I I I I I I I 321.5 326.1 328.5 329.2 10 100 285 14320.7 14420.7 14705.7 14895.7 15400.8 0.5 0 -4.6 -1.6 -0.7 0.05 143.21 0 144.21 -0.46 147.06 -0.16 148.96 -0.01 149.96 -0.07 150.96 -0.07 154.01 p 1993 Stream Profile HEC-RAS Plan River Sta Min Ch EI (tt) 2756 3061 298.3 302.5 Lenglh Chnl (ft) 10 305 Cum Length Chnl (tt) 10 315 X-sec 1 starts about here + about another 96 tt dis 3571 303.3 510 3591 303.2 2.0 f>(, ", 3596.5 Bridge -viI {,'-'-'-' ~._ 3602 303 .. 2 0.1 3622 304.4 20 825 845 845.1 -bT~ '?~oo I I I I I I 4047 304.3 425 4397 303.2 350 4507 304.3 110 865.1 I 1290.1 ~5 W A J 1640.1 I'~ 1" 6 ~ V"" u 114,"l1ti 6" Al 4518.5 Bridge 148th Ave Bridge AM 4530 ~ 0.1 4580 ~ 50 4630 305.3 50 4825 305.3 195 5310.5 Bridge 5316 306.9 5366 306.4 6041 305.8 6646 306.8 6652 Bridge 6658 307.2 6708 306.8 7123 306 7618 . 308.4 7628 308.1 7634 Bridge 0.1 50 695 605 0.1 50 ic-. 455 495 10 ~- 7640 308.1 0.1 7650 308.4 to 8835 307.1 1185 9985 310.4 1150 10935 310.1 950 11435 313.3 500 11735 313.5 300~ 11835 313.5 100J 1750.2- 1.800.2 1850.2 2045.2 2045.3 2095.3 2790.3 3395.3 3395.4 3445.4 3900.4 4395.4 4405.4 4405.5 4415.5 5600.5 6750.5 7700.5 8200.5 8500.5 8600.5 ~~....., A.4.--I 41 ~, ~ I~'~ ~~~ I I I I I I I AS. 11849 Bridge 164th Ave Bridge -,?~"'--~=~oEQg,-;,.pt"":~==--"'1l~8:S4!~1QI0.e.:.y# 12323 313.3 410 9060.6 b.j,), ,Q11, -d f V 1' I.L I 13143 315 820 9880.6 13893 316.4 750 10630.6 14608 316.5 715 11345.6 15488 318.5 880 12225.6 16148 318.7 660 12885.6 16953 319.8 805 13690.6 17563 321.6 610 14300.6 J. : ,\ A'0J _~I:. ~. 'i I I I I I I I I I I I I I I I I I I I I I 17573 322 10 14310.6 ';:e.q(O 17602 Bridge Renton-Issaq. Road Bridge CV\I>e . .J 17631 322 0.1 14310.7 17641 \EiiJ 18 14828.7 y;if q. / 17741 321.5 100 14420.7 18026 326.1 285 14705.7 . 18216 327.7 190 14895.7 . 18316 327.8 100 14995.7 Sf \1\ "1\1, Rd.. 18322.5 Bridge 10 is aboul here 18329 mM::-c-:-:-:-:~--~~~-? .{of (0 .-I E;~i~i~e"; ht: 15095.8 U 19400 .8 I/'~'~~'~ . M!!:U ~ t?: ""-V' ~ \ '" ~ ~ ') ~ .........., ,,-", \ 1.jJ j ..... '" '-,--, LG 0 .~ " ... ~ ~ (f:J j\ '" , , . 30. I 1.1 H--- 0)0 I I I I I I I I I I I 11~1---r--+--~:!-------a:t Z'~U'MU .\'JP __ ------------;- --- T~( ------ ... j..-/ v~~ .... i· .... ! ..... ~ .... Q I ,.",) c) ~"s .' ----' ,~1 "'. "" v ." '" . I "" '" ~ '" ~ I" - -------------------------------------- I I I I I I I I I I I I I I I I I I I 1)/> I t J (S 1979 May Creek Basin Plan's Stream Profile Sta.ID Elv Chnl Lenllth Cum Lenllth 1 299.8 0 0 rt 1.1 299.3' ~ 30 14 CP 304.9 >842 2A 304.2 225 1067 3 304:7 ~ 1747 Iq.g:t QJ5 -;~~:~'S~m 1787 ,"'" 3A ' '391';-0 " 2",,3058 j "----4-308.2 4805 4A 306.1 ,. c.:1@ 6173 5 310.7 ,,),~ 7302 I(,q~@ 313.8 17 9038 c_ 314 ~ 9078 7 317 ,263 , 11708 8 317.1 4,8 13056 SA 319.9 384 13440 9 320.8 (f42P 14862 <;R<jooGP 321.5 [~ 14922 '<;f 0<"1 ~? 328.2 15512 v-i {"I' 11 328 @ 15870 G'l I ~ \JU' t "\ \1 c ... .c:. c: ~ '" E: .c: u ... ... c: '" '" u E c '" v: c: 0 Rotton Selll'lent ~ ... ~'J i dth LenQth '" u or (ft. ) ~ .... Pioe ~ ... Di~. c: CII (ft. ) '0 CHI4 1290 CU 1.5 80 CH 5 100 CU 1.5 30 CH 3 400 CU 1.5 30 CH 2 110 3(') 1,800 40 30 1,850 20 2,840 2,090 ---. ... If)~n·\~:Ir:.\,[ln F, A~5.0CI:.TE~ '··W eRHI: nr~n;~r.~ 5T!'['" \1~·~!1."i~\', 1977 "'~OP' I j Inlet Outlet Il~nk Slooe [lev. [lev. Vert.tHori z. (ms1) (I'1S 1) !,'AY 1451.3!.5 426.0:!:.5 1/1 1/1 426.0!.5 422.4!.5 - 422.4:!:.5 416.4*.5 2/1 2/1 416.4!.5 415.0±.5 - 415.0±.5 395.2*.5 1/1 1/1 395.2t.S 3Q4.8t.5 - 394.8 t .5 385.9*.7 1/1 1/1 385.9*.7 384.5*.5 - 384.5±.5 357.1)*.5 1/2 1/2 357.0±.5 356.0!.5 1/4 1/4 356.0!.5 355.9*.5 - 355.9*.5 339.8*.4 3/5 3/5 339.8±.4 339.7t.4 - 339.7t.4 327.9t.4 1/1 1/1 Vert. 1.5/1 1/1 HCiX • Flo\-.' Depth IRouQ~ness (ft. ) 13 1.5 . 3 1.5 2 1.5 3 1.5 2 1 3.0 3 3.0 3 5 3 1.5 ream Orde Gra;sy roads i de ditch Concrete Roadside ditch Concrete Roadi sde ditch Concrete Roadside ditch Concrete Na tura 1 channel Brushy CorruQiI ted s tee 1 Soil bnl:, mud Bottom sand, grilvel, mud 1 Remnks Inflow at Se~ment 003 at upstream end. Two driveways. Bank erosion. Driveway. Rank erosion. Driveway. Bank erosion, small inflow from Sub- catchment 3. Driveway. flank erosion. After inflo~1 of Segment 044. Driveway to camPQround in Subcatch- ment 5. Begin Harstad profile (1965). Private drive; SE 109th Street. Under Below inf1o~1 of SeQment 116. 6.1 CorruQated s tee 11." ·'!~ftlc·'IIj!/;'~~':'q.~!!t1;~-'}~llftf' ~ 2: 8 x 8 foot cu1 vert '. elr on upstream end 1/1 3 1 .5/1 1/1 13.0 Vert. Vert. 4.5 1313.5±.3 I 3'l9.8±.41 1.5/1 11/1 14 ~'ud bottom, grassy ba nks IHeavy brush in channel 309.8±.4 305.1\~r !1 ~.5 Jravel bottom 305.1:!:.4 305.9*.4 .5/1 .5/1. 3.5 !1ud bOttOM - -." --~",-. .0.-=- and 2.4 foot on downstream end. Below inflow of Segment 195. If!!!' .!_'._-._-:~,t-.: I,,;~·"".;f,'.,,'_I-in flow of Below inflO\~ of Segment 319. 8elow inflow of Segment 333. -.-- - - - Cl I , N Ie..> +> &:: a: E: .= .s --r --,-934 CH 16 ~~~ ~~ 17 , .. 950 I flP. p2 951 CH 30 905 15 ,030 _ ,220 '1 ,390 1,050 200 30 280 490 30 Y")~n·\·il r.V[':T Ft ~~·S"'I(! !'T[~ I.~,,~· r:p.rn: flf'~~',r,r:~ ~,.~!:'\ Inlet 1 ev. 1) nutlet Elev. (!'Is1) RAnk Slooe I"·ax. Vert./Hori z. Fl 0'" Depth IRouo~ness (ft. ) eft \Rioht 1.5/1 1/1 3.5 IMUd bottom Vert. Vert. 5.6 r~ud bot tom 1303.5!.413O4.1-1.411/1 1/1 4.0 Thick .mud bot 304.1t.4 304.0!.4 Vert. Vert. 8 Five 1.5 foot 304.0!.S 7t .5/1 . S/1 supports 2.5 Gravel bottom 300.7!.4 300.4!.4 -6.8 Concrete 300.41.4 24311 .511 .511 4.5 Gravel bottom 243±1 186i2 1/1 1/1 4 186 t 2 147.1t.5 1/1 1/1 3.5 147.1t.S 121.3t .S 1/1 1/1 4.5 121.3!.5 107.2t.5 1/1 1/1 3 107.2i.5 100.2±.5 1/1 1/1 3.S 100.2-1.5 100.1±.5 -7.25 10O.lt.5 100.Ot.5 1/1 1/1 3 100.Ot.5 89.3±.5 1/1 1/1 3 89.3!.5 90.4!.S Vert. Vert. 6 ",'i~ 90.4±.5 . 1,050 77.4!.S 1/1 1/2 2.5 IGravel bottom 3,980 77.41:.5 34.0!1 1/1 1/1 3 2S0 34.01:1 32.0tl 1/1 1/1 50 930 32.0tl 21 .2!.1 1/1 1/1 3 IGravel boHom 30 21.2± .1 21.2t.l 1/1 1/1 12 3 21.5±.5 21.St.5 Vert. Vert. 6 Concrete 50 20. S!l 20. 6±. 1 1/2 1/2 .5 15 20.6!.1 20.S!.1 Vert. Vert. 12 530 -+ 20. S:!:.l 16.2±.2 2/1 2/1 5 1 25 16.2±.2 15.5t.2 Vert. Vert. 6 I Concrete 480 15.5!.2 12. g±. 2 2/.1 2/1 4 r,rave 1 43,801) Total .. ",·::.1~~'·. 1 q77 P. ne 14 KernarJo:S 8elow inflow of Se~ment 345. 16 . .,: :,' .\, ~ . ~,: .. ~. )etlilNH inflow of Se~ment 369. --- . J< I Small bridge. (1% / Small arch brid~e. End Harstad profile; 136th Ave. bridqe does not affect f10\~. Below Senment 472. Be 1 0\'/ Se~ment 535. Below Seqment 994.(Honeydew Creek). Below Se~ment 763. Below Segment 787. Bridge over ME 31st. Riorapped banks. Below Segment 784. Bridge over NE 31st; elevations double checked. Below inflow of SeQment 816. 1-405 freeway bridge as built in 1956 Lake HashinClton Blvd. USGS Gagin~ Station; V-shaped wei r '"loS C : :Jx. Railroad bridge. !·1an-made chAnnel; enter Lake \·Iash. JA JORDAN I AVENT a. ASSOCIATES Segment Parameters ,:.:,CJlo1Q'-' ". May Creek StudY, . . Page 4 After the subcatchment was divided into segments, each was described.by seven parameters as required by the SHMM rodel: . , 1) Channel bottom width OR pipe diameter 2) Segment length. 3) Inlet elevation 4) Outlet elevation 5) Bank slopes 6) Roughness 7) !~aximum flow depth Existing information ~/as reviewed to minimize field work. Major SOurces included: 1) 1 ongitudi na 1 This study provided For four of the ei"ht miles of ~1ay Creek, a with cross sections every 100 feet was surveyed-. information for Segments 912 -931. 2) Topographic maps with 5, 10, and 20 foot contour intervals. These maps were crucial to check surveyed elevations, to supply spot elevations at many pOints, and to estimate some reMOte inlet and outlet elevations. 3) USGS topographic map of 25 foot contour interval. In spite of the large scale, these maps provided the most accurate positions of stream channels. The upstream elevations of most natural channels in the uplan1s were taken from these maps. 4) En~ineerinq plat maDS for urbanized areas. These were used to locate storm sewers. As requested, all storm sewers greater than t\-/elve inches are shown on the base map overlay. As can be clearly seen. most residential areas do not have storm sewers. 5) Road crossing plans for 1-405, State Highway 900, 148th Avenue and 164th Avenue. In addition to describing channel segments, they provided references and checks for our survey. Values from the RIBCO study were rot used. A brief discussion about the accuracy, sources, measuring techniques and other pertinent information for each parameter may help in using the da.ta most effectively. G-4 JORDAN I AVENT & ASSOCIATES Channel Bottom lJidth: May Creek Study Page 5 For Segments 912 -931, bottom width was measured by averaqin.!I four to eiqht Harstad cross secti.ons within each segment. In a majority of cases, bottom width was measured in the field. Please note that for trfbutaries flowing from the hills, channel dimensions were measured only on the down- stream end. If additional descriptions are needed, these seqments can be· further investigated. Normal channel irregularities limited accuracy to· within one foot. For Segments 919 -927, the completeness of the Harstad study enabled us to stretch this to within ~ foot. Pipe Diameter: Culvert diameters were nearly all measured in the field to within ~.l foot. Bridges were measured as accurately as possible, from t.OS to !.5 foot. In the table in Appendix 2, care should be taken to notice that crossinqs may have rectanqular, oval or circular cross sections. Seqment Length: Smaller values (less than 100 feet) were usually determined in the field by pacing. These are !2 feet. Lon!ler distances were measured and carefully compared on the. base map and on at least one other. map. Values from the most accurate map were chosen •. Therefore, base map distances may not be the same .as distances on the table. The table values should be regarded as the most accurate. Table values are at least ~20 feet. Inlet and Outlet Elevations: Determination of elevation represented the majority of tiPle expended. Because of the absence or destruction of almost all benchmarks in the baSin, most surveys were run from points of known elevations. These included spot· elevations on road and topographic maps, engineering plat maps and bridge· plans. The precision of these starting elevations has been taken into account in G-S ....... -.. -~------------- JA JORDAN I AVENT II< ASSOCIATES May Creel< Study Page 6 assessinq accuracy. E1evationssurv~ed from benchmarl<s and these spot elevations are usually listed as !.5 foot. The elevations of some remote segments were taken ·from maps of 5 foot contour interval. They are evaluated as t2 feet. Elevations from the USGS map of 25 foot contour interval are assessed as I !5 feet. Elevations taken from the Harstad profile are given as !.4 foot. Bank Slopes: In Segments 912--931, bank slopes were measured on the Harstad cross sections. For most segments, banI< slopes were estimated in the field. Natural channels are usually not trapezoidal as required by the S~It·1M model; and, therefore, precision in these values should not be expected. 11axirnum F10l~ Depth: A~ain the natural changes and irreqularities of stream channels prevented great accuracy in measuring the bank full depths. Values should be considered to be within one foot. Measurements for culverts represent the actual depth available for flow as of January, 1977. If the culvert has been filled. this I~ill be evident because the maximum flow depth will be less than the pipe diameter. The accuracy of maximum flow depth in pipes is t.l foo.t. r~aximum flow depth may :hanqe during flood conditions due to scouring or.filling. Roughness: Roughness was described briefly to aid in selection of a Manning's n. Culverts were noted as . either concrete or corrugated steel, and the general conditions of channels were stated. For the mainstream of tlay Creel<. roughness due to mid channel vegetation can be most adequately described by examining .. the available air photos. G-6 I I I I I I I I I I I I I I I I I I I GU;"I ()::'~ i I q C:, ) t(~~TktJ 4T<AJ'/ __ ~3~0 ____ .~~q 1 :E ~-,::: ~ .~""'i ""'-e'l ,~ -;;;;;~_J.J81~0 _______ -J.1!§!5~l§. 0:::: '"' a 2200 3010 ____ -=:c.-/' "--\,0 0 3530 6540 l4955 ------------- -;n~25~~6~~5W, 12755 2090 8655 9225 [:::::;?""-==:::......!I~b~C(2_.Ilr~· -- 3100 11755 200-~ 1320 13075 7110 830 13905 4010 25 13930 2690 --;;;90::-5-...!.:14~8;1135LL .. --~~~ -,-~.-.• ;::-!4-? 1lr -;~:;:r,~~~'\'"'~;~:~~~!Q.~~ .. _. --~-~.-=--ILtC~ 20 15765' 20 - ... ID .-:'7 - ~.---1.&' TABLE 1 -SUMMARY OF DISCHARGES (Cont'd) Floodina Sourc~and Location North Fork Issaquah creek At mouth At mouth (including overtopping from Issaquah Creek) East Fork Issaquah Creek At mouth West Fork Issaquah Creek Above Issaquah Creek confluence 2,900 feet upstream of 229th Drive S.E. Above tributary confluence near 208th Avenue S.E. Holder Creek Above confluence with Carey Creek Tibbetts Creek At mouth May Creek At USGS gage 12-119600 At Coal Creek Parkway -: _~!; 14.6th AvenUe .5. E. At 148th Avenue S.E. At 164 tit _,!l,.'!:~n1,1_I;! __ S~_~ • .._ ..... __ ..... At S.E. Renton-Issaquah Road At S.E. May Valley Road At S.E. 109th Place May Creek Tributary Above confluence with May Creek Vasa Creek At mouth At cross section R Drainage Area (sq. miles) 4.8 4.8 9.5 4.9 4.7 1.5 7.5 3.9 12.7 8.9 7.7 6.9 4.8 2.9 . 1.2 0.9 1.5 1.37 0.53 - - - --- -- - 10-Year - 176 176 440 290 270 100 420 220 480 350 310 280 .200 130 59 46 72 55 24 - Peak Discharges (cfs) 50-Year IQQ-Year 269 489 725 460 440 160 660 355 315 835 950 550 530 200 800 425 SOO-Year 445 1,995 1,100 790 770 280 1,150· 600 , 800 870 1,020 580 640 750 520 56Q 660 470--·--·--510 600 340 370 440 --220--·--·-·-24-0-----280- - 100 110 130 78 87 100 120 81 39 140 93 44 - -- 160 123 60 - - - I I I I I I I I I I I I I I I I I I I Kln~ County /viAL Su ace Water J!l13 \I~. Management Everyone lives downstream Comp -rll~ Engineering & Environmental Services Date \ f. -'NG-\) I 5T,A;N u:: 14-[, 1l!---f 14 g 111-- I fa4 1lf:- C?lZ-qoo lP~( ~'c/7{( ~J SWM-EngWorkSheel 4122193 (P(Bi. Project /171-q{lZf:{M P/2'DPLfS Chk Rev c\ Date Date Page_ot_Pages D/;-r.&-':> 0 v t: r.-c-"--"--'--'- I "'cA(ooJ~ 1f/.1 =." .L q"Gt -rt..-{ ::rr-,YI'\- VL-MJ 1-""7e:C • "VJ(.<7"t ) flA I u:.S ( ( g q8/ '1<;0 qo)' , ( I 0G7f C~i)o 7~1Z ( I I 61 q) '0 '77/0 S-7rr ---_._ .. _ .. _-_ .. -- ( 13ff0S/ j 11-, DLf)-f !?kZ) I . _ .... _._-'-- T A B l Ii FLOODING SO.URCE CROSS SECTION May Creek A B C D E F G H I J K L M N o p Q R S T U V W X Y Z IMiles ·Above Houth DISTANCE I 0.14. 0.16 0.24 0.25 0.31 0.39 0.46 0.52 0.57 0.63 0.78 0.94 1.09 1.25 1.36 1.39 1.41 1.42 1.46 1.54 1.56 1.61 1. 74 1.83 1.96 2.02 WIDTH (fUT) 34 60 42 42 31 40 28 23 45 31 33 79 33 39 32 40 33 33 30 22 8 43 27 38 52 42 FEDERAL EMERGENCY ~ANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS FLOODWAY nellOH .". (SQUARE fEn) 158 239 99 110 121 150 87 123 165 89 133 143 113 128 89 172 90 111 95 91 68 283 81 170 101 130 MEAN VELOCITY (fEET PiR SECOND) 5.5 3.6 8.8 7.9 7.2 5.8 10.0 7.1 5.3 9.7 6.5 6.1 7.7 6.6 9.6 4.9 9.5 7.7 8.9 9.3 12.5 2.9 9.9 4.8 8.0 6.3 REGULArORY 21.0 21.8 23.3 25.7 29.0 32.5 35.8 40.0 41.8 45.3 55.2 64.7 76.4 85.4 93.1 95.6 95.8 96.4 99.8 106.8 112.2 114.2 120.9 125.0 135.8 140.4 BASE FLOOD WATER SURFACE ELEVATION WITHOUT I WrTH. fLOODWAY fLOOOWAY (fEEt NGVO) 21.0 21.8 23.3 25.7 29.0 32.5 35.8 40.0 41.8 45.3 55.2 64.7 76.4 85.4 93.1 95.6 95.8 96.4 99.8 106.8 112.2 114.2 120.9 125.0 135.8 140.4 21.5 22.2 23.3 25.7 29.2 33.0 35.8 40.6 42.5 45.3 55.2 64.7 76.6 85.4 93.2 96.0 95.8 96.4 99.9 106.9 112.2 115.1 120.9 125.7 135.8 140.5 FLOODWAV DATA· ·MAYCREEK INCR(AS~ 0.5 0.4 0.0 0.0 0.2 0.5 0.0 0.6 0.7 0.0 0.0 0.0 0.2 0.0 0.1 0.4 0.0 0.0 0.1 0.1 0.0 0.9 . 0.0 0.7 0.0 0.1 - - ----------- -- ----.-~.-... '\ .. -. "'. , .. """.-... -.. ~-." -..... . • ----_. __ .. - BASE FLOOD WATER SURFACE ELEVATION FLOODING SOURCE FLOODWAY SECIION M(AN REG TO V WITHOut WITH CROSSUCTION DISTANCE' W(,IOTH, ARU VELOCITY UlA R FlOOOWAV ftOODW EEl (SQUARE (fEET PER Kay Creek (Cont'd) AA 3.23 AS 3.34 AC' 3.49 AD 3.68 ~\--J/ -?AE ~.74 .c-~ AF Sf( 3.80 LI% 1Il. e>i2.)AG ~ 3.90 I I AH (o.n,.:.) 3.99 ~'l' ok .. 1(/'1< .... ",2.) AI ''1lQ&' 4.07 , AJ G 17" 4.13 AK 1b~ t. % zqo AL (/.+ ..... ) "1<Z! 4.37 '" AM· 1'71) ~ AN 1~Z-' f4,'4.58 I. AO 4.68'v AP -4:'90 AQ ,5.12 ~ AR 41 1( 5.30 ~11J(,1-BI', ') AS un y;", ) q,<il(( AT AU AV (I.o'f""t) AW ~ t;-W( AZ 1HilesAbo../e Houth: 5.56 5.72 5.86 6.00 6.16 6.29 6.44 -.;J (";I?'l~l e>kt 'll? 37 33 41 40 15 21 18 53 19 92 75 231 96 137 19 133 US 44 12 73 85 184 216 50 100 170 T A B L E FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS 4 fEU) U(ONO) (FEEl NGVO) 124 78 135 134 78 80 105 257 92 371 303 983 387 540 78 559 325 120 57 413 444 743 491 70 271 324 5.1 8.2 4.7 4.8 8.2 8.0 5.3 2.2 5.5 1.4 1.7 0.5 1.3 0.9 6.5 0.9 1.6 4.2 6.5 0.9 0.8 0.5 0.8 5.3 1.4 1.1 266.4 278.3 289.6 300.3 304.3 306.5 309.2 310.0 3~0.2 311.5 311.5 311.8 311.9 312.1 312.5 313.4 313.8 315.5 319.2 320.3 320.3 320.4 320.4 321.9 323.2 324.0 266.4 278.3 289.6 300.3 304.3 306.5 309.2 310.0 310.2 311.5 311.5 311.8 311.9 312.1 312.5 313.4 313.8 315.5 319.2 320.3 320.3 320.4 320.4 321.9 323.2 324.0 267.3 278.3 290.2 300.3 304.5 306.9 310.0 310.7 311.1 312.1 312.3 312.8 312.9 313.1 313.1 314.4 314.8 316.0 319.2 321.1 321.2 321.4 321.4 322.2 324.2 324.8 FLOODWAY DATA MAY CREEK .. _ .. --........... ..... -" ...:.......-:..~ INCREAn: 0.9 0.0 0.6 0.0 0.2 0.4 0.8 0.7 0.9 0.6 0.8 1.0 1.0 1.0 0.6 1.0 1.0 0.5 0.0 0.8 0.9 1.0 1.0 0.3 1.0 0.8 T A B L E FLOODING SOURCE (ROSSilCTION DISTANCE' WIDTH (fEn, Hay Creek (Cont'd) ce qo~) BA 6.56 13 BB 1\1~1 6.65 138 "iE ""Ii'f "¥I$'C 6 .. 70 11 BD 6.78 34 -BE 6.93 61 BF 7.10 33 BG 7.24 11 IHiles Above Houth, FEDERAL EMERGENCY MANAGEMENT AGENCY _ KING COI)NTY, WA AND INCORPORATED AREAS I FLOODWAY SleTtON ARlA {SQUAfI.( fUll 40 106 26 58 48 37 26 BASE FLOOD WATER SURFACE ELEVATION MEAN REGULA10RY WiTHOUt 1 :fL=~.\Y· INCREASE VElOCIty flOODWAY (fffT PER SECOND' (fEU NGVO, 6.0 324.3 324.3 325.3 1.0 2.3 329.5 329.5 329.5 0.0 4.3 330.8 330.8 331.4 0.6 1.9 332.0 332.0 332.8 0.8 2.3 334.1 334.1 335.1 1.0 2.9 338.1 338.1 338.8 0.7 4.2 341.9 341.9 342.7 0.8 . FLOODWAY DATA MAY CREEK lFeet Above Mouth 2Elevations Computed Without Consideration of Backwater from May Creek , FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPO~ATED AREAS FLOODWAY DATA MAY CREEK TRIBUTARY , --.,-- - - - - - - - - - - - - - - - - 100 ,. 80D I'~k' -Ot' 70 . r: :M:. ,- g ~ 60 ~ w !C 7-o ~ ~ 50 l~mm :t:t --'~r rf!-Jlm'--r - , , ~ l:rmm .. i II l-nrrlTCP+! e 40 ~ T >t 30 L ~ :r- -f-t 1< ... -~ Jt:ammtit J!li1-1: .j. LEGEND '00 ,. BO 7. 500 • YEAR FLOOD 100· YEAR FLOOD 50· YEAR FLOOD 10-YEAR FLOOD 20 20 ;T~' ~l~!ht-n: I ~ STREAMBED j¢[~~F Lm~ 1m L6 CR~~~ON ,. '0 0.1 0.2 0.3 0.4 0.6 0.6 ._7 •. B 0.9 STREAM DISTANCE IN-FEE'fABOVE MOUTH HUs. 1.0 1.1 1.2 1.3 1.' en ... ..... ;:: :.: co ... ::: ~ ~ i co ..... ... > u z w " • .. z ~ w ~ ... .. CO< ~~ " -... • >-0-z 0-.. ~ z: "" =>0 > 0 "-~ (.) D:: w <.:> 0 " z: ~ '" -z: w ""_ ~ c w z: ~ .. '" w Q w ~ 109P I I I I I I I I I I I I I I I I I I I --~ " ' 011 I I I I I I I ~ m Q m n M ~ g U z '" -< Q " a! '" ' :. m < < < !: ~ m ,. m m :;jm m '" '" ,. ,. !I~ m ~ ~ '" '" " ~ ~ ~ ~ l! § g ~ ~ " g 8 c c FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS " '.' "~,, ELEVATION (FEET NGVO) ';j-F '+, FLOOD PROFILES MAY CREEK H-+t '~ +T. I II -'r~----------------I t+++l+i4tHH,","i.;f,eL!+;.d..!d."'li"'!Il'.!<fil"'jqi';:'l:i:':L~:'ihrj""L:.t"":'~.r.·iji.~:L.L.. '-'_'" _1'".1'.' •• _,1 •• '.,',1.,,1,',11 IT :P ; :;",;,.!; ,"",::i j .!: 11.:i .. Trl~~Tlrl··-T r _" .• ',f-f-t:l - , ::'.' ii' . ',"'" 11"'''i'! '''+1··:' ,f·:~li-;j:.:· q: .. !:: .. ~ I ': \" I" ',I :' :,!,~ !-, l"r L!-IT-t" ...;·I-J. t.~-l--f.ftitf:\:l:tl:t:l:l,::t'l:IT .~q';;:!I .. l~:;!i.!-qi _~·_~·:~ .. 'l-I·-""'"I!-:"!H -H+·,-". .' -~-.1: ~"'~, r "ltc" t'"'' 'YEr ,,}!;lj~!:~;mf L ,,-,-,u, L ill Lrn· ,n, d I' .. :. :MY '. j. ; ... &--'-315--:":'-'-'-'-'-' 29. rGF=F' Ij ~ ttl"Wi''''''r+';H'tyt': q iI .·t'fj": ,.1 ,. .{...l-,-.. -!-...... I '.' 0 I - -I '-....L...! .. [. , i t· 1 . , .. ,:. . ~ -'. , . ; .. .: 'I . . I . . . • • ~ "5 -j: 'h" ~ 'j I±-~i!'i+:' .; /!! I; .>.,:!:':'; l·::~:;: i:',! t· !d:JJ~· ~~~~~~~~~~~~~~i~~~~~~~~~~~ L ,.,,].,1 ~I ,w,,",; I .. ..I,.11i", ,;,v;, , 'c, ~.~~ 1":7 " :t]/r~T ': :.Xi." f, ' '.'. ;;" _ •. ,.! oJ':' '7' 'I:; '~8 "'.1 :~.:J •• o'-~o~ !",:,_. ,_._ .. '}jii' . .. . . T ..... 1 ... • ff:T:t78:1~~~ffMtI~rffi#ffifd, iii :.:.' :11 " 0'; , .. ", .. , , .... '. , -,. ,.;. ~}~;:-T75"[~~ n~:...:. ,+,..+..t++--;-j.l·-+'·t~·t' +"-fJdMt~t: ;1:.::( ,; i ii' [ili \: J ilt'f 1""<-, : . . .. .. . .." ,_ _ _ ." _ 2 ••. " :.,.,.,+ ::' ...... ,; --. " 1 •• ...:..:. .. 2 ... ~·r ",'" '.'hf--, i-:.-r,j~_ "d-jmR,T!Ff8:I;-;j+I'ttmttl-ftll-.-rJ"~ '.'.::~t4i.~ ':':.:.:.:r:~j it "Ii~ ':" .: ",., ,., :1 '.:';-j' I1t:f-1 TI 11\ ' ;--.,--".,", ·f .. , ",.:.,' "11 " ., . , .. " •. ':'. -"il,e".t' 'l:rllH 2 •• iJ.il·nl:.!;;~;<:,.. ~:,~~~ ___ ' ~':h~.L ... _~: ',~_. :.~frf: .. D. :.~'!'iL.~ ~::~. IJ;,;' ,,~,:: Ii' .,' ~ ..' !,oi--t-~l~iinmjk,. ... , ~" ' '+1" : ; , t·'''· , ___ .. 1 . _.J.2.JL:...... ..\_ .. " 'ff:lli:.:! 'i', 1 ;tbI; II .... ., .. 1 ~ ........ : : r: ,-; . 500 -YEAR FLOOD ------100· YEAR FLOOD -----50 • YEAR FLOOD -------10· YEAR FLOOD ~ STREAM BED A CROSS SECTION lOCAnON 3.1 3.2 3.3 3.4' 3.5 3.6 3.6 3.7 3.8 3.9 4.0 4,' 4.2 •. , STREAM DISTANCE IN MilES ABOVE MOUTH' en .... ..... '" ... .... = .... ... "" ... <> >-= < = = ::E ..... ... ~ ~ en ~ < ... .... z < "" ; =--< w -c " -.... ~ >-1- Z 1-< ~ z: "" ~ ~C> > =11. ~ c.l c::: w <:> C> " z: t.> ~ -z: S !II:_ w ~ < ~ l!I w ~ c z: < lllP I I ELEVATION !FEET NGVOI I I J.tH:,-t +;--H+::=tti: IVAlbG,::jf I .~ I . ' I I I I I I I I .a:t±±l, ;'-:p-:, . H- ." . i, I I II I I I i FiR -. I I n 0 ;; iii ~ ., ~i ~ :. ~ m < ~ ~ m m >0 > > .,m ~ ~ " -n m ~ ~ 0., Zo " ~ § 0 Z 0 " " ~ 1 + ~ I FEDERAL EMERGENCV MANAGEMENT AGENCV flOOD PROFILES - I -~ KING COUNTY. WA AND INCORPORATED AREAS MAY CREEK , . , ! , I I ___ . _______ .... -.--.--II---II---------------Jl!!!!!L- 340 335 r-; t,·,· -i-' -:- 330 ... , Tr '. ';:r~--··'·r·~· ... ,-,-,,' l·'~·'++·'·' I··' .,-;L!, ;.~,I "·,·,H r·f· :':1 ::~-1'+~L.;tF ",:LCi]:t.L" t ~" "i·~+t+ t ~-h+t-t}+;· -~ 6oJ.ANDhob!YEAFi )OO&GQfNGfOE . , 1·' .• " Je" '" . __ :.t" -I"T -t~· -j-~"f~' ,';"1.,:. m '· L:j~:t '""'lj:j:I+H/' -:: t -.. i+~ttr -:t ~'±r": ~ :::i tilT' ):1 f' + itT;. TttTf1. ~ l:;,~±r+:t-1f~l; Eli'T"""--' z 325 1 ' "'i "T t~t$:i± t;;.;"' .c4W~: TfctLE(,f;rh*t . rin l·l-tfr:r:;t;}~tJ:~~w· i fn-HHfi ; i{iffitfE l't( ~320~ w w~ ~ ~lfq~~,,· 316 ----'-r-----,---,-----'-, ' :;~+~~,j;.tl~~L,,!~i: --: ~ t :-1-r-"'[" 1;·1-.....-, ---;--·i~.fE+Lt 11}'; ~ +.-:-- 310 6,6 ,,7 6,8 5,' 11:J ,.," ~".1.,". ,., " "".!: ,,'. ... "'¢Lh:~; ;-tti ~:' .,.1); /i~t:;~~~; ;: '- ., ... 1T i~.t: ; :P ~ff I ~!F:~::",:·::;:U+:l+FFL, "'FIl~-Jt,1 Fr.,~ H·l;iiii:; -. '''-_i~W.~t ,: r,~-~J:: +.r=:t~.i 1::--. '.:rlr;ttJ: .,,-... --;.; ,..L..."' ,.~~:ttfn:~-TIiE+0-- li:J#mt b.d::-:~ , t::~ .:.q-h'!" ·+f-ti.d..:t-°' r.l:~ '~i-;'~ ll~' :~~ 1~~~t~ .. ;j . _ : ," t rMI; !:..!l:t-.,.,. ~_t,~.r: .... ~. .:fW'+I+l,.',c ;:1 h j1f;·l-lltF T':fU ~ ·tt:~~~q.i: ~,;L';~t~: :~:ttL -. '!i'lj·ill-!i1-·t) j~": .. '.'-~: .. , .;.~' :;+ ,~1:jIF .r-/.f.! l.._ . 1 ~ tr 1,-1-·· • to J I r ,. . IIff1l ',:,,;. ~L:i~"'i+t'~tl.'·~ + :.i.. ",,).4 ±r!:1' +,.,;.'.,.; l,' JT' '. '-' W+i:nJ, r r' . '-:Ii. H-tti·~ !-:-.:-::.1 ;·~~t~ :t:+=!"rfH . .,0 .,1 .,2 6,3 h.~ •. 4 \:. ~ I STR EAM DISTANCE IN MILES ABOVE MOUTH f. ~ '\.'- I 340 330 I '" ... ..... ... i C> a: .... '" >- 330 I C> i C> C> ..... ... I 325 11111111111111111::: '. • w 0 en • ~ i::5 • w "" "" 310 ! ~q LEGEND ~ .. fa z ~ .... 500 • YEAR FLOOD • z"" '" => "" 100 -YEAR FLOOD ~ CO z ","- 50· YEAR FLOOD w "" o ~o 10· YEAR FLOOD ~ z<> w -z '" ""-~ STREAMBED w 0 ~ z • 6 CROSS SECTION ~ "" w LOCATION D w ~ 8,5 8,. .,7 .,8 a" 1I3P I I I I I I I I I I I I I I I I I I I --~ ~ ,", rr t iii "r , . ~tW 01 I. I I I I I I I I I I I I ~ I m ~ m " ~ g ~ § Z ~ ~ 0 , 8 0 6~ ~ m < < < < ~ ~ m ~~ ~ m m :lm m ~ ~ ~ ~ o~ m ~ ~ ~ ~ 0 ~ ~ ~ ~ 20 g 8 ~ ~ Z o 0 0 0 o 0 o 0 , : ,:'-j-; FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS ElEVATI~N.IFEET NOVDI " r",-H-· ~ * iT , "I=J: -+ f I· I!: =4 ~:t;41J ...!.~--!-' , " , " FLOOD PROFILES MAY CREEK ------------ I" . -~~. . '-',,--', ~;-:-, .. -. _ .. ~! "I it I~II ," -' . :':';" ...... ," '-' .. -. --.. .. ... -.. -,. , .. ~' . . :I>e l>ell> ~ Ii) I ~ }' ~ ~ lH ~p r II a ~ 1 t- t i i " ql - • ~ I !i '. ~ ., ... il! 1 .. ! ~ i:. • r--.. 'I; - .11 l:" tH!I - j J j twe I • • i I :-:-: I ~ ~r':' ~tut' --II i· .. ~i: ~ , I'-'~ i .11 . ' ..... II ....... ~_ • .......,.. •. ,.··)~~~~{f*~;~~.~;~~i~ij I I I I I I I I , , I: ! I I , Ii I I I I I I I' I I: Ii . , I I I Ii I Ii I: I I I I 1 I I· I I , "'.' . ,." . .","' ., . I!Sa iii I~IJ ',::.' '.':., . .' ,: ... :.;;,~ .: ';"_~'.~;,':i:' -'"'' .. ;, ... , .. --: . , . 1 1 , \ ,! \ II " , ti . "l 11 •• i ::l~ - ~ .~ 1. >3l l~ • . . .. .. ,. < •. . ..• , .•. ,,"' .. ,., ~ . r.·: , 1>< \.e\ I ! ~ - .. , .:~ , . . \ I :~ loll I - ~ i~i , {I I - -, I ! i , -:-- ~ I""" I JH I ~ 1M-- ~ I , , ~ ...... . do.. t ii I ::;;... .,... • _:c ~ -n , I ; ..... -I :-- . i\ Ia- " ~ '15-::'1 , , t'i1 T '3! r- :I-I~ ~~ I I iU ill II II II II II JA JORDAN I AVENT a. ASSOCIATES Remarks: t1ay Creek Study Page 7 Remarks included any suprlemental information which might help to describe the segment or subcatchment. Land use for each subcatchment was entered in this column. Other comments included: Street names to aid in locatin!] culverts, clarification of inflow of one segment into another, or the existence of storm sewers or curbs. Please note that streets in this area have changed their names and numbers several times. those taken from street signs. PROBLH' AREAS Names or numbers 1 isted under remarks are \ The second objective of this study was to photograph and briefly comment on areas subject to serious flooding, erosion or sedimentation. Forty-ei~ht color slides and their descrirtions are included in Appendix 1. flooding The problem of flooding along Hay Creek has been a subject of local concern for several y~ars. Harstad and Associates were contracted in 1965 to plan flood control correctives. Their solution was channelization. This plan was never carried out, ~nly for financial reasons. Flooding and high water tables are problems in a 170,000 foot reach of middle and uppper May Creek. More specifically, this area begins about 2,500 feet above the Highway 900 bridqe over Hay Creek, High water problems also exist in the valley which extends southeast toward Issaquah. In this valleypondinq is a frequent problem from May Creek almost to the basin divide, a distance of about 3,400 feet. The cause of flooding in this section of the valley .is Simple: ·low channel gradient. Flooding problems end where the channel slope again increases, i.e., about 800 feet below the 143th Avenue bridge. Seasonal hiqh water presents a G-7 I I I I I I I: I Ii I I I I I I I I I I I ~----------------------- /' .•.. ~.;;:r . Washington Department of " FISH and . WILDLIFE HYDRAULIC PROJECT APPROVAL EXHIBIT 28 RCW 77.55.021· See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: 123184-2 N/A Project Expiration Date: August 10,2016 FPNPublic Notice #: PERMITTEE AUTHORIZED AGENT OR CONTRACTOR King County Water and Land Resources Division ATIENTION: Doug Chin 201 S Jackson St Ste 600 Seattle, WA 98104 206-296-8315 Fax: 206-296-0192 Project Name: Project Description: . May Creek Drainage Improvement Project (9A 1205) Improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. Remove vegetation and instream debris which is impeding flows and dredge 4,050 cubic yards of sediment from May Creek. Stream and wetland mitigation consists of: 1. Enhancing a 15 foot wide buffer of vegetation on each side of May Creek. 2. Installation of off-channel alcoves adjacent to May Creek downstream of 148th Ave. SE. 3. Restoration at the lower end of Long Marsh Creek. PROVISIONS 1. The project may begin immediately and shall be completed by August 10, 2016, provided work below the ordinary high water line (OHWL) shall occur only between ~une 16 and September 15 2. NOTIFICATION REQUIREMENT: The Area Habitat Biologist (AHB) listed below (e-mail to fisheldf@dfw.wa.gov) and the Enforcement Program Officer (e-mail to capeljlc.@dfw.wa.gov) shall receive e-mail notification from the person to whom this HPA is issued (permittee) no less ihan three working days prior to start of work, and again within seven days of completion of work to arrange a compliance inspection. The notificatipn shall include the permittee's name, project location, starting date of work.or completion date of work, and the control number of this HPA. 3. Work shall be accomplished per plans and speCifications approved by the Washington Department of Fish and Wildlife (WDFW) entitled, "MAY CREEK DRAINAGE IMPROVEMENT", dated September 15, 2011; "LONG MARSH CREEK RESTORATION", dated July 18, 2011; and "May Creek Drainage Improvement"Project (9Q1205) King County Water and Land Resources Division Stream and Wetlal")d Impact Analysys and Mitigation Plan", dated revised September 2011, except as modified by this HPA. A copy of these plans shall be available on site during construction. . 4. Installation of project mitigation components are required to compensate for impacts of the project on fish life and shall be overseen by a qualified stream ecologiSt. 5. A temporary. bypass to divert flow around the work area shall be.in place prior to initiation of other work within, the wetted perimeter. Page 1 of 6 1.:.2-. Washington Department of -~ FISH and _ WILDLIFE HYDRAULIC PROJECT APPROVAL RCW 77.55.021 -See appeal process al end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPAlPublic Notice #: North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425)775-1311 123184-2 N/A 6. A sandbag revetment or similar device shall be installed at the bypass inlet to divert the entire flow through the bypass. . , 7. A sandbag revetment or similar device shall be installed at the downstream end of the bypass to prevent backwater from entering the work area. 8. The bypass shall be of sufficient size to pass all flows and debris for the duration of the project. 9. Prior to releasing the water flow to the project area, all instream work shall be completed. 10. Upon completion of the project, all material used in the temporary bypass shall be removed from the site and the site returned to preproject or improved conditions. 11. The permittee shall capture and safely move food fish, game fish, and other fish life from the job site. The permittee shall have fish capture and transportation equipment ready and'on the job site. Captured fish shall be immediately and safely transferred to free-flowing water downstream of the project site. The permittee may request that WDFW assist in capturing and safely moving fish. life from the job site to free-flowing water, and assistance may be granted if personnel are available. 12. Any device used for diverting water from a fish-bearing stream shall be equipped with a fish guard to prevent passage of fish into the diversion device pursuant to RCW 77.57.010 and 77.57.070. The pump intake shall be screened with 118-inch mesh to prevent fish from eritering the system. The screened intake shall consist of a facility with enough surface area to ensure that the velocity through the screen is less than 0.4 feet per second. Screen maintenance shall be adequate to prevent injury' or entrapment to juvenile fish and the screen shall remain in place whenever water is withdrawn from the stream through the pump intake. 13. Dredging shall be accomplished by starting at the upstream end of the project boundary and working downstream. 14'. Dredging shall be limited to deepening of the streambed. Banks shall not be disturbed. /-----~----------- 15. Upon completion of the dredging, the streambed shall be contoured with pools and riffles similar to its configuration prior to the dredging. "1---------' 16. Salmonid spawning habitat at the confluence of Long Marsh Creek with May Creek shall not be impacted. There shall be a minimum of 18 inches deep spawning gravels there upon completion of dredging . . 17. Materials plilced at the outlet of the. culver! on Long Marsh Creek shall consist of rolJl)dee bouldeJs,.cQgble.~, and_g~ther than the riprap shown on page 4 of ~for .Long Marsh Creek. . . Page 2 of 6 I Washington , ". -Department of '.' . ~ FISH and _ WILDLIFE HYDRAULIC PROJECT APPROVAL RCW 77.55.021 ~ See appeal process al end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August .10,2016 FPNPublic Notice #: North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012~1296 (425) 775-1311 123184-2 N/A 18. Fish habitat components as shown in the approved plans (Provision-3) are required as part of the project to mitigate project impacts. Large woody material installed as fish habitat components shall be coniferous and shall be installed in a manner sufficiently far from the bank to provide fully functioning fish habitat and shall be securely anchored to withstand 190-year peak f1o~s using ) buried anchors and heavy duty chain or sufficient rock ballast. --.. -.. -...•.. 19. Disturbance of the streambed and banks and their associated vegetation shall be limited to that necessary to perform the project. Affectea streambed and bank areas shall be restored to preproject or improved habitat configuration. Prior to December 31 of the year of project grading, the approved planting plan (Provision 3) shall be installed. Project performance standards, monitoring, maintenance, and contingencies shall occur as described in this plan on pages 27-28. 20. Equipment used for this project shall be free of external petroleum-based products while working around the stream and wetlands associated with the stream. Accumulation of soils or debris shall be removed from the drive mechanisms (wheels, tires, tracks, etc.) and undercarriage of equipment prior to its working below the OHWL. Equipment shall be checked daily for leaks and any necessary repairs shall be completed prior to commencing work activities along the stream and wetlands associated with the stream. 21. If at any time, as a result of project activities, fish are observed in distress, a fish kill occurs, or water quality problems develop (including equipment leaks or spills), immediate notification shall be made to the Washington Emergency Management Division at 1-800-258-5990, and to the AHB. 22. Erosion control methods shall be used to prevent silt-laden water from entering the stream and wetlands associated with the stream. These may include, but are not limited to, straw bales, filter fabric, temporary sediment ponds, check dams of pea gravel-filled burlap bags or other material, and/or immediate mulching of exposed areas. 23. Prior to starting work, the selected erosion control methods (Provision 22) shall be installed. Accumulated sediments shall be removed during the projectand prior to removing the erosion control methods after completion of work. 24. Wastewater from project activities and water removed from within the work area shall be routed to an area landward of the OHWL to allow removal of fine sediment and other contaminants prior to being discharged to the stream or wetlands associated with the stream. 25. All waste material such as construction debris, silt, excess dirt or overburden resuliing from this project shall be deposited above the limits of floodwater in an approved upland disposal site. 26. If high flow conditions that may cause siltation are encountered during this project, work shall . stop until the flow subsides. - Page 3 of 6 ----------------------------------- I Washington Department of HYDRAULIC PROJECT APPROVAL North Puget Sound :, '" FISH and , WILDLIFE RCW 77.55.021 -See appeal process at end of HPA 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425)775-1311 Issue Date: September 26, 2011 Project Expiration Date: August 10, 2016 Control Number: FPNPublic Notice #: 123184-2 NIA 27. Extreme care shall be taken to ensure that no petroleum products, hydraulic fiuid, fresh cement, sediments, sediment-laden water, chemicals, or any other toxic or deleterious materials are allowed to enter or leach into the stream or wetlands associated with the stream. NOTE This HPA is a modification of and supercedes the original HPA issued August 11, 2011 for this project. The modification pertains to updated plans referenced in Provision 3. PROJECT. LOCATIONS Location #1 May Creek rm 4 :3 to 4 9 WORK START: September 26,2011 IWORKEND: August 10, 2016 WRIA: --Waterbody: Tributary to: 08.0282 May Creek Lake Washington 1/4 SEC: Section: Township: Range: Latitude: Longitude: County·, ---- NW 1/4 02 23 N 05 E N 47.51149 W 122.13461 King Location #1 Driving Directions Location #2 May Creek rm 4 3 to 4 9 WORK START: September 26,2011 \WORKEND: August 10, 2016 WRIA: Waterbody: Tributary to: -- 08.0282 May Creek Lake Washington 1/4 SEC: Section: Township: Range: Latitude: Longitude: County: NE 1/4 03 23 N 05 E N 47.51599 W 122.14429 King Location #2 Driving Directions APPLY TO ALL HYDRAULIC PROJECT APPROVALS This Hydraulic Project Approval pertains only to those requirements of the Washington State Hydraulic Code, specifically Chapter 77.55 RCW (formerly RCW 77.20). Additional authorization from other public agencies may be necessary for this project. The person(s) to whom this Hydraulic Project Approval is issued is responsible for applying for and obtaining any additional authorization from other public agencies (local, state andlor federal) that may be necessary for this project. This Hydraulic Project Approval shall be available on the job site at all times and all its provisions followed by the person(s) to whom this Hydraulic Project Approval is issued and operator(s) performing the work. Page 4 of 6 , Washington Department of HYDRAULIC PROJECT APPROVAL , FISH and RCW 77.55.021 -See appeal process at end of HPA " WILDLIFE Issue Date: September 26, 2011 Control Number: Project Expiration Date: August10, 2016 FPNPublic Notice #: This Hydraulic Project Approval does not authorize trespass, North Pugel Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425)775-1311 123184-2 NIA The person(s) to whom this Hydraulic Project Approval is issued and operator(s) performing the work may be held liable for any loss or damage to fish life or fish habitat that results from failure to comply with the provisions of this Hydraulic Project Approval. Failure to comply with the provisions of this Hydraulic Project Approval could result in a civil penalty of up to one hundred dollars per day andlor a gross misdemeanor charge, possibly punishable by fine andlor imprisonment. All Hydraulic Project Approvals issued under RCW 77.55,021 are subject to additional restrictions, conditions, or revocation if the Department of Fish and Wildlife determines that changed conditions require such action, The person(s) to whom this Hydraulic Project Approval is issued has the right to appeal those decisions, Procedures for filing appeals are listed below. "'- Requests for any change to an unexpired HPA must be made in writing. Requests for new HPAs must be made by submitting a new complete application. Send your requests to the department by: mail to the Washington Department of Fish and Wildlife, Habitat Program, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. APPEALS INFORMATION If you wish to appeal the issuance, denial, conditioning, or modification of a Hydraulic Project Approval (HPA), Washington Department of Fish and Wildlife (WDFW)recommends that you first contact the department employee who issued or denied the HPA to discuss your concerns. Such a discussion may resolve your concerns wi~hout the need for further appeal action. If you proceed with an appeal, you may request an informal or formal appeal. WDFW encourages you to take advantage of the informal appeal process before initiating a formal appeal. The informal appeal process includes a review by department management of the HPA or denial and often resolves issues faster and with less legal complexity than the formal appeal process. If the informal appeal process does not resolve your concerns, you may advance your appeal to the formal process. You may contact the HPA Appeals Coordinator at (360) 902-2534 for more information. A. INFORMAL APPEALS: WAC 220-110-340 is the rule describing how to request an informal appeal of WDFW actions taken under Chapter 77.55 RCW. Please refer to that rule for complete informal appeal procedures. The following information summarizes that rule. A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request an informal appeal of that action. You must send your request to WDFW by mail to the Washington Department of Fish and Wildlife HPA Appeals Coordinator, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. WDFW must receive your request within 30 days from the date you receive notice of the decision. If you agree, and you applied for the HPA, resolution of the appeal may be facilitated through an informal conference with'the WDFW employee responsible for the decision and a supervisor. If a resolution is not reached through the informal conference. or you are not the person who applied for the HPA. the HPA Appeals Coordinator or designee will conduct an informal hearing and recommend a decision to the Director or designee. If you are not satisfied with the results of the informal appeal, you may file a request for a formal appeal. B. FORMAL APPEALS: WAC 220-110-350 is the rule describing how to request a formal appeal of WDFW actions taken under Chapter 77 .55 RCW. Please refer to that rule for complete formal appeal procedures. The following information summarizes that rule. Page 5 of 6 ------------- Ie Washington , , Department of " . FISH and , .' WILDLIFE . HYDRAULIC PROJECT APPROVAL RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPNPublic Notice #: North Pugel Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775·1311 123184-2 N/A A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request a formal appeal of that action, You must send your request for a formal appeal to the clerk of the Pollution Control Hearings Boards and serve a copy on WDFW within 30 days from the date you receive notice of the decision, You may, serve WDFW by mail.to the WaShington Department of Fish and Wildlife HPA Appeals Coordinator, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov;faxto (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. The time period for requesting a formal appeal is suspended during consideration of a timely informal appeal. If there has been an informal appeal, you may request a formal appeal within 30 days from the date you receive the Director's or designee's written decision in response to the informal appeal. C. FAILURE TO APPEAL WITHIN THE REQUIRED TIME PERIODS: If there is no timely request for an appeal, the WDFW action shall be final and unappealable. ENFORCEMENT: Sergeant Chandler (34) P1E Habitat Biologist Larry Fisher CC: 425-313-5683 for Director WDFW Page 6 of 6 ,--------------------------------------- EXHIBIT 29 May Creek Drainage Improvement Project Biological Evaluation Report for: Chinook Salmon and Steelhead Trout as protected under the Endangered Species Act May Creek, King County, Washington State Prepared for: King County Water and Land Resources Division Department of Natural Resources and Parks 201 South Jackson Street Sle 600 Seattle, W A 98104-3856 Phone number: (206) Prepared by: Mistie Hammer King County Road Services Division February 2011 Acronyms BE BMP DPS EFH ESA ESU HUC LWD NOAA Fisheries NMFS RM SPCC TESC WDFW WLRD WRIA WSDNR Biological Evaluation Best Management Practices Distinct Population Segment Essential Fish Habitat Endangered Species Act of 1973 (amended 1996) Evolutionarily Significant Unit Hydrologic Unit Code Large Woody Debris National Oceanic & Atmospheric Administration -Fisheries Department National Marine Fisheries Service River Mile Spill Prevention, Control, and Countermeasures Temporary Erosion and Sediment Control Washington State Department of Fish and Wildlife King County Water and Land Resources Division Water Resource Inventory Area Washington State Department of Natural Resources ,-------------------------------- Table of Contents INTRODUCTION ...................................................................................................... 1 1.1 Consultation Activilies ............................................................................................... I 1.2 Description of Proposed Project Action .................................................................... I 1.2.1 Description of Project Elements ................................................................. 3 1.2.2 Project Sequencing and Timeline ............................................................... 6 1.3 Impact Avoidance and Minimization Measures ........................................................ 7 Construction Equipment: ............................................................................................ 7 1.4 Action Area ................................................................................................................ 9 2 FEDERALLY LISTED FISH AND WILDLIFE SPECIES IN THE ACTION AREA .................................................................................................................................. II 2.1 Chinook Salmon ....................................................................................................... II 2.1.1 Critical Habitat.. ........................................................................................ II 2.2 Steel head Trout ........................................................................................................ II 2.2.1 Critical Habitat.. ........................................................................................ 12 3 ENVIRONMENTAL SETTING .............................................................................. 12 3.1 May Creek Basin Overview ..................................................................................... 12 3.2 Habitat Conditions at the Project Location .............................................................. 13 4 4.1 4.2 4.3 5 6 3.2.1 Aquatic Resources .................................................................................... 13 3.2.2 Wetlands ................................................................................................... 15 3.2.3 Geology ............................... , ..................................................................... 15 EFFECTS OF ACTION ............................................................................................ 16 Direct Effects ............................................................................................................ 16 I ndirect Effects ......................................................................................................... 16 Effects from Interrelated and Interdependent Actions ............................................. 18 CONCLUSIONS ....................................................................................................... 19 MAGNUSON STEVENS FISHERY CONSERVATION AND MANAGEMENT ACT .......................................................................................................................... 21 6.1 Essential Fish Habitat Background .......................................................................... 21 6.2 Description of the Proposed Action ...................................................................... : .. 21 6.3 Adverse Effects Essential Fish Habitat for Salmon ids ............................................ 22 6.4 6.5 7 Essential Fish Habitat Conservation Measures ........................................................ 22 Conclusions .............................................................................................................. 22 REFERENCES ......................................................................................................... 23 Appendix A ....................................................................................................................... 25 Appendix B ....................................................................................................................... 28 Appendix C ....................................................................................................................... 37 ----- 1 INTRODUCTION 1.1 Consultation Activities No consultation with National Marine Fisheries Service (NMFS) has occurred. Species under NMFS jurisdiction were investigated through the development of a series of special studies completed as part of the project selection process, as well as by means of personal communications with local fish and wildlife authorities and a review of pertinent literature. The personal communication included conversations with Larry Fisher, Area Habitat Biologist and Aaron Bosworth, Anadromous Fish Biologist for the Washington Department ofFish and Wildlife (WDFW). The literature review included: the WDFW Priority Habitats and Species database and species maps (dated October 29, 20 10); the Washington State Department of Natural Resources (WSDNR) Natural Heritage Information System, and list of rare plants and high-quality native plant communities and wetlands in King County. 1.2 Description of Proposed Project Action The purpose of this Biological Evaluation (BE) is to determine if the proposed action may affect any species listed by the NMFS. Section 7(c) of the Endangered Species Act (ESA) requires that projects with a federal nexus evaluate and document impacts to threatened and endangered species and their critical habitats before funding, authorizing, or carrying out an action that may affect the species or their environment. A BE is necessary for this project because of its federal permit (from the Army Corps of Engineers). Information on listed species and habitats known or potentially occurring in the project vicinity was provided by state and federal agencies (Appendix A) and is summarized below (Table I). Table 1: Information on Listed Species in the May Creek Project Action Area Species and Habitats Federally threatened endangered, and proposed plant species and communities Federally threatened and endangered and proposed fish speCIeS Critical habitat for federally threatened and endangered species Agency WDNR NMFS NMFS Data Provided No species or communities occur in the project action area. Two threatened species could occur in the project action area: I-Puget Sound Chinook salmon ESU 2-Puget Sound steelhead trout DPS No critical habitat is present in the action area King County Department of Natural Resources and Parks, Water and Land Resources Division (WLRD), proposes to improve in-stream flow conditions along segments of May Creek. Sediment accumulation and in-stream vegetation (e.g., reed canarygrass and ------------------------------- The project is located in unincorporated King County and the City of Renton in Sections 2 and 3 of Township 23 North , Range 5 East (47.51521 N latitude / -122.14301 W longitude) (Figure I). The May Creek drainage basin is part of the Lake Washington watershed (6 th field HUC 17110012030 I). The project is located in the May Valley and construction activities will directly impact May Creek (WRIA 08.0282) and Long Marsh Creek (WRlA 08.0289). Figure 1. May Creek Drainage Improvement Project Vicinity Map 2 May (','eek f'h tlnrlel Re"tor-.. lion Project Pl'6jrd YI<'inlty Stud y A raa Inc.Orponl ted Ar eas Couga r Mou nta in 'Midla nd Park • ,.. .., ,ttl -_ ..... __ ... ..... -::....-:-._. __ .-::f ____ _ ~~;=7~_; ...... _-_ ........ -_ .. --_ ..... '- Figure 1 1.2.1 Description of Project Elements King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. This project proposal consists of three components: vegetation removal, sediment removal, and stream/wetland mitigation. The vegetation and sediment removal will negatively impact existing in-stream fish habitat, so mitigation has been proposed to offset these impacts. The mitigation is also designed to improve the longevity of the project by decreasing the opportunity for channel obstructions to form in the future. A temporary erosion and sediment control (TESC) plan will be implemented. TESC measures will be installed, inspected, and maintained throughout construction as determined by the plan. Control measures will be installed and in place prior to ground- disturbing activities. All clearing limits, staging area perimeters, and site boundaries will be flagged and/or fenced. 1.2.1.1 Vegetation Removal The first component of the project includes removal of approximately 2,550 linear feet of flow obstructing in-stream vegetation and debris from speci fic reaches where it is choking the channel creating a backwater effect. Water trapped behind these channel constrictions result in extended periods of flooding on adjacent properties during storm events. Invasive reed canarygrass is the dominant vegetation that will be removed from the channel and banks. In addition, willows located in multiple locations throughout the project area, are currently growing in the middle of the channel, further contributing to the backwater effect. A portion of the willows (along approximately 1,070 linear feet) that are identified as obstructing flow would be removed (Figure 2). The willows will be primarily removed by hand, but some small, hand-held, mechanized machinery may also be used. The reed canarygrass that is growing in the channel will be removed with machinery, most likely a trackhoe, operated from the stream bank. During removal of the reed canary grass, the stream would be diverted around the construction site and erosion/sediment control best management practices will be implemented to minimize temporary downstream water quality impacts. 3 ------------------------------------------------------------------------------------ Figure 2. Willow Pruning Exhibit 1.2.1.2 Sediment Removal TIlt' selrc tivt pnaling ofillt u.isling wUJows would w donr as shown In the IIttubf'd plctun. TIlt' obJtrtln ortbt pruning would W 10 reduc t' lht br:mchu thM cross tilt .~f1 I'run nlld c:nch nf'd cnn:ar y g ... u innIs lhllt brt:t1; loolit upstream. L. Tht willow brancble1i (ltd I'Irrow) IlJ:\t :uf'btlowtlltWllltl \'iould bf' pl'wled bnck 10 thf' In :Ull inlllk of Ihf' willow . 2 . TIlt willow bll'lllches (blut nrrow) would bf' PIIUlf'd so Oint they would nOI block nows till'll ue c ootninf'd w ithin the stre:U1\ b::mks . 3 . Tilt willow bUllt heli (ytlloW lIHOWS) tli :u pro\idt tbt' 1i h::adt c anopy for Ihf' stream would not bf'touc lif'd , ... Tht 1001 syn~no( tht' willow lh:n Is providing bank ,t.billty I'lnd SII e~n cOll\l)lu:hy would not bt toucilf'd. The second component of the project includes the removal of accumulated sediment from the stream channel. Sediment would be removed using machinery, most likely a trackhoe, operated from the stream bank. As with the vegetation removal process described in section I .2.1. I., the stream would be diverted around the construction site and erosion/sediment control best management practices will be implemented to minimize temporary downstream water quality impacts. Construction techniques, such as utilizing existing access roads or using non-permanent steel plates (or equivalent) where additional access is needed, would be used to minimize temporary impacts to adjacent wetlands. Approximately 4 ,050 cubic yards of material will be removed from the stream channel. Sediment removed from the stream will be temporarily stockpiled in designated soil drying areas (Appendix B, Sheet 2 and 3) immediately after removal from the stream. Once the soil is dry, it will be hauled ofTsite and disposed of at an approved location. 1.2.1.3 Channel Modification May Creek's channel will be modified by the dredging activity, as well as by in-stream mitigation activities . The dredging activities will result in a uniform channel elevation at 308 feet (NA VD 88) with varying channel cross sections (Appendix B, Sheet 4). This channel modification will occur in May Creek from approximately river mile (RM) 4.3 to RM 4 .9. The dredging construction techniques were described above. 4 1.2.1.4 Conservation Measures The mitigation was designed to provide compensation for removal of existing in-stream vegetation (i.e., reed canarygrass and willows) and sediment by enhancing the existing riverine wetland and riparian buffer, as well as restoring instream habitat function at the confluence of Long Marsh Creek and May Creek. King County has developed multiple basin reports and action plans for the May Creek subarea over the years and the proposed mitigation incorporates the results of these studies. The mitigation goal for this project is to increase project longevity and to achieve no overall net loss in habitat functions in the May Creek subbasin. In most ofthe project area the regulatory stream buffer is contained within the delineated wetland boundary, which means that stream buffer enhancement could also be considered wetland enhancement. Compensatory mitigation objectives include: Wetland Habitat: Enhance about 2.24 acres (this includes 2.0 acres of riparian habitat described below) of riverine wetland adjacent to May Creek downstream of I 48th Avenue SE by suppressing invasive vegetation and replanting native wetland vegetation. About 0.24 acre ofthis enhancement will be in the form of off-channel alcoves along May Creek with emergent wetland vegetation, woody debris, snags, and gravels. This mitigation will enhance fish and wildlife habitat by increasing habitat complexity. Riparian Habitat: Enhance about 2.0 acres (included in the 2.24 acre of wetland habitat) of riverine wetland/May Creek buffer by suppressing invasive species and planting a 15- feet wide buffer of native vegetation along both banks of May Creek from· I 48th Avenue SE upstream to the end of the project limits (about 2,500 linear feet on each stream bank). This buffer is intended to shade out future reed canarygrass and to compensate for the cover that would be lost by removing flow obstructing willows and reed canarygrass. The native riparian vegetation would be planted in areas where, under existing conditions, virtually no native vegetated buffer exists. Fencing will also be installed around the planting areas to minimize livestock access to the stream. In-stream habitat and function: In-stream mitigation activities will occur in two locations. In the first location, 0.24 acre of off-channel alcoves (these are the same alcoves described above under Wetland Habitat) will be excavated along May Creek west of 148th Avenue SE. The existing banks will be replaced with a terrace (wide bench) and gradual slopes. Sixteen (16) pieces of large woody debris (L WD) will be placed and native vegetation will be planted in the alcoves (Appendix B, Sheet 2) and streambed gravels will be placed along the first 15 feet adjacent to May Creek. Jute matting will be placed in the alcoves beyond 15 feet to minimize erosion, and the alcoves will be densely planted with emergent and scrub-shrub wetland plants. During a flood, water will inundate the terrace and interact with the woody debris and vegetation. This will increase the amount of available in-stream habitat and will decrease flow velocities, thus improving the quality of off-channel overwintering habitat. Sediment deposition will occur outside of the main channel in the alcoves. The woody debris and vegetation will trap and hold sediment and then allow a more gradual pulsing of sediment back into the channel over time. 5 The second location will restore in-stream fish habitat complexity and alluvial fan functions at the confluence of Long Marsh Creek and May Creek. The project will enhance approximately 300 feet of the lowest reach of Long Marsh Creek by creating meanders, adding habitat features, and planting native vegetation, These enhancements will improve the sediment trapping capabilities of the Creek to reduce transport of sediment to May Creek. The enhancement also includes creation of an approximately 100 foot long side channel parallel to May Creek that will join with Long Marsh Creek prior to discharging to May Creek. (Appendix B) This mitigation will improve winter rearing habitat for salmonid and other fish species in areas adjacent to the main stem of May Creek. The mitigation will increase biological functions for riparian species within May Creek through introduction of woody debris; woody debris will also provide substrate for invertebrates, hiding habitat for juvenile fish, perching habitat for riparian birds, and desirable niches for river otters, other mammals, and crustaceans. The proposed mitigation is also designed to enhance refuge and rearing habitat through the establishment of habitat features along May Creek. Such enhancements would make these habitat features available to salmonids and other wildlife species at a wider range of May Creek flow rates. In addition, willows and other native shrubs will be planted along streambanks and confluence margins to increase cover of overhanging branches above the waterways. Lastly, the removal of reed canarygrass and root system from the floodplain will create additional area for sediment deposition, thereby allowing some decrease in the volume of fine sediment moving downstream. 1.2.2 Project Sequencing and Timeline Project construction is expected to take three to four weeks to complete, with plantings occurring in the spring. The time line detailed in table 2 assumes the in-water work window issued by WDFW to be August 1-31, which is typical for tributaries to Lake Washington. 6 Table 2. Construction Sequencing and Timeline Date I-Aug 4-Aug 4-Aug 5-Aug 5-Aug 6-Aug 7-Aug 14-Aug 26-Aug 30-Aug I-Sep 17-0ct I-Apr Activi Locate and Mark Utilities Install Temporary Erosion and Sediment Control (TESC) Measures Install Temporary Construction Access Ramps and Entrance Pads Install Staging Areas Fish Removal Install Stream Bypass (in-water) Selective Removal of Vegetation Sediment and Reed Canary Grass Removal (In Channel) Construct Mitigation Area (grading and L WD) Remove Temporary Stream Bypass (in-water) Remove Temporary Access Ramps and Pads Remove TESC Best Management Practices (BMPs) Install Plantings 1.3 Impact Avoidance and Minimization Measures The following project elements will be implemented in order to minimize project impacts on listed species. Site and Equipment Preparation: • The contractor will install temporary high-visibility fencing and silt fencing to demarcate clearing limits and protect sensitive areas according to the approved TESC plan. No work. including the placement or stockpiling offill materials or excavated materials, will be performed in any sensitive area. When it is no longer needed or at the engineer's direction, the contractor will completely remove and properly dispose of temporary high-visibility fencing and silt fencing. • A TESC plan and a Spill Prevention, Control, and Countermeasures (SPCC) plan will be developed and implemented by WLRD for this project and will be used at all times. As construction progresses, erosion-control measures will be re-Iocated or newly installed if necessary so that as site conditions change erosion and sediment-control measures are always functioning in accordance with local and state erosion and sediment-control standards. Construction Equipment: • Refueling operations will be conducted at a minimum distance of 100 feet from an open water body, or ditch, and an SPCC plan will be prepared by the contractor and approved by WLRD prior to the initiation of construction to ensure that all pollutants and products are controlled and contained. Additionally, drip pans will be fitted with absorbent pads and placed under all equipment being ~I~. . 7 • All vehicles operated within 100 feet of the creek will be inspected daily for fluid leaks before leaving the vehicle staging area. Any leaks detected will be repaired before the vehicle resumes operation. When not in use, vehicles will be stored in the vehicle staging areas. • Construction equipment will use existing farm access roads, whenever possible to cross wetlands. • Construction equipment will not enter any water body without authorization from WDFW, as appropriate. Equipment will be operated as far from the water's edge as possible. Debris, Erosion, and Disturbed Areas: • The contractor will install temporary high-visibility fencing and silt fencing to demarcate clearing limits and protect sensitive areas according to the approved TESC plan. No work, including the placement or stockpiling offill materials or excavated materials, will be performed in any sensitive area. When it is no longer needed or at the project manager's direction, the contractor will completely remove and properly dispose of temporary high-visibility fencing and silt fencing. • All debris from construction and removal activities will be contained and disposed of in accordance with federal, state, and local laws. • Erosion of disturbed areas will be controlled using silt fence staked and keyed-in (depth of five inches); use of mulching or hydroseeding, planting disturbed areas to establish cover vegetation, or other similar approved methods to contain erosion. • All exposed areas that will be unworked for more than seven days during the dry season (May I to September 30) and two days during the wet season (October 1 to April 30) will be covered in accordance with the project's TESC plan. o Disturbed areas will be restored to pre-project conditions or better, using site- appropriate native plant species. Stream Work: • In-water work will be conducted during the in-water work window listed in the hydraulic project approval issued by WDFW. Typical windows for tributaries to Lake Washington allow an in-water work window of August 1 to August 31, though final approval from WDFW has not been issued. o In-water work will be limited to activities required to bypass the creek, including fish exclusion and installation of cofferdams. The remainder of project activities will occur once the stream has been bypassed. • Work will not inhibit passage of any adult or juvenile salmonid species after project completion. • Sediment-laden water generated during construction will be pumped to an infiltration or filtration site, or to a settling area, where it is subsequently treated and sediments are consolidated prior to returning water to streams. Discharge of water back to streams will occur in such a manner as not to cause erosion. • Machinery access along the stream, in areas where there is a willow canopy, will only be allowed approximately every 50 feet to minimize disturbance to native vegetation. 8 • In-stream willow removal will be limited to the minimum amount required to restore flow conditions. Branches that are crossing the stream and obstructing flow will be removed by pruning the branches back to the trunk. Willows that are providing canopy cover for the stream without obstructing flow will not be removed, and similarly, the willow roots that are providing bank stability will not be removed. 1.4 Action Area The action area includes all areas that could potentially be affected directly and indirectly by the federal action, and not merely the immediate area involved in the action (50 CFR 17.11). This area is the geographic extent of the physical, chemical, and biological effects resulting from the Project, including direct and indirect effects, and effects of interrelated and interdependent activities. Effects from the project are not expected beyond the action area (Figure 3). Terrestrial: The terrestrial portion of the action area is delineated by the point at which project related noise generated by construction equipment attenuates to background noise levels. Construction noise levels where estimated assuming use of dump trucks and trackhoe/excavator and the distance at which noise levels attenuate to background is 1,200 feet. Aquatic: In the aquatic portion of the action area, the effects from project activities would occur through water-quality impacts. Direct effects from turbidity and siltation resulting from construction activities will be minimized through the implementation ofBMPs and impacts are not expected to extend beyond 100 feet downstream as required under Washington Administrative Code 173-201A-200. This limit was established based upon the type of construction activities that are to occur, the location of those activities in relationship to the creek, timing of construction, and the implementation of BMPs through the TESC plan. Indirect effects resulting from reductions in sediment transport may extend 3.2 miles downstream of the project, near the confluence with Lake Washington. Sediment potentially transported this distance is assumed to deposit in the lower 2,000 feet of May Creek, where the gradient becomes less than one percent. 9 o May Creek Channel Restoration Project Action Area Legend D Action-A.rea -Streams and Rivers "* Project Location' I~'~"~~ <~.t'" '~': ,",.4.-f . ',~ '1:,';'! "~ ~, \ ~:8~:-?;" r.'"'";'~~~'-"/ ,;,<\(""~",,, Y'1f"".n I'? 1~"'-i /.' '" !Z,' ,:.i. .. \ ~ .;:,.: __ ,:" -,,:t': .. ,.~ "'\ -~t:,' .. , ~" ","", \1;;:; ,,~, • ~-:.r. N A 'If"' 0.2 0.1 0 0."2 0.4 0.6 Miles --U1: King County Th 1f> .. 4>t_C'IO<.~N.t~'--I ... ,,«wop""f>,' IlgOJo ,\"'tlII_~ 1J",\,,,,., • .,., ... <lI,..,~ctb ?:;~~:to,:.~;:t:.; .p"',t1II:>uor Rtta,,,; . .,p,m' ~11t(>~'llll t>ao;:"""f,,",,,'II>"U.1b.M,,'.O! 8)11' blot u.or"Ci 11t>"~1I!1 lIl'tr. ... rtll(llll" ".a tf ..... :"""~r""'rt IlgO>o.\".I,dtolto tI ... ftUfl'\II"DI..~~nL 11"~t 1tCII •• QI.(tr"" .... I .. ,~.-"7< """'-g."'! ,oll"'It<l". btl ... "" Q' ~<tp"'l; ''''1111~.'''' to '~'lI"'II"""1tt ItlCIII""'''''''tI1o'''~IO.''4'. ~'i:.n _.,."" '" 11> .. "", o,'n ,,~, I f'l~ll'I'~ .... I'Ii." ..... puntobl cttlyOU'\"' ">j ;a' = ~ !H "0 a -. a ~ o· = > ~ 2 FEDERALLY LISTED FISH AND WILDLIFE SPECIES IN THE ACTION AREA Based on a review of an endangered species listing provided by the WDNR (dated November 5, 2010) and NMFS (accessed January 24, 20 II; revised July 1,2009) the following species have been evaluated as part of this biological evaluation: Chinook salmon and steelhead trout (Table I). 2.1 Chinook Salmon In 1998, NMFS conducted an ESA status review of Chinook salmon populations from Washington, Idaho, Oregon, and California and determined that Chinook salmon in the Puget Sound region constituted an evolutionary significant unit (ESU) and that the Puget Sound ESUis at risk of becoming endangered in the foreseeable future (Meyers et aI., 1998). Following this status review, the Puget Sound ESU was federally listed as threatened in 1999 (Federal Register 1999). Primary factors attributed to population declines include habitat blockages, hatchery introgression, urbanization, logging, hydropower development, harvests, and flood control and flood effects (NMFS 1998). Chinook salmon are not present at the project location, but have been documented approximately one mile downstream, within the project action area; lifestages present include adult spawners and rearing juveniles. Adult Chinook typically arrive On the spawning grounds in May Creek in October and finish spawning in November. Fry begin emerging in January and continue through early-to mid-March. Juveniles typically rear in fresh water for a few months before migrating downstream in the spring. Chinook in May Creek likely represent fish straying from the Cedar River and Issaquah Creek and do not represent a reproducing population. Nearly all spawning occurs in the lower two miles of May Creek, though spawning has been observed up to RM 3.0. The number of Chinook observed in May Creek varies between zero and 12 fish annually (pers. comm. Aaron Bosworth, WDFW, November 15,2010). Preliminary results of WDFW spawner surveys conducted in 2010 in May Creek observed three live Chinook and one redd. Surveys were conducted weekly from September 22 to November 10 and the Chinook were observed on a single survey within the middle reach (RM 0.4 to \.8). 2.1.1 Critical Habitat No critical habitat is designated in May Creek; the nearest critical habitat for Chinook salmon occurs in Lake Washington approximately 4.3 miles downstream of the project location, below the downstream extent of the action area. 2.2 Steelhead Trout Puget Sound steelhead were listed as a threatened species on June I I, 2007 (FR Vol 72, No 9 I p 26722). The DPS includes all naturally spawned anadromous winter-run and summer-run steel head populations, in streams in the river basins of the Strait of Juan de Fuca, Puget Sound, and Hood Canal, Washington, bounded to the west by the Elwha River (inclusive) and to the north by the Nooksack River and Dakota Creek (inclusive), I 1 as well as the Green River natural and Hamma Hamma winter-run steel head hatchery stocks. 0. mykiss can be anadromous or freshwater resident (and under some circumstances, apparently yield offspring of the opposite form). Anadromous 0. mykiss are called steelhead and non-anadromous (freshwater resident) forms of the species are usually called rainbow trout. Those that are anadromous spend one to four years in fresh water prior to smoltification, although most within the Puget Sound ESU smolt after two years in fresh water. Steelhead then spend one to four years at sea before returning to their natal streams to spawn. The steelhead run in the Lake Washington basin is characterized as "depressed" (WDFW, 1992). Past hatchery practices by WDFW included planting of steelhead fry throughout tributaries in the Lake WashingtonlLake Sammamish Basin and were unsuccessful in producing return adult spawners. The Cedar River has a naturally spawning population of steelhead and weekly surveys are conducted annually to assess abundance. Redd counts have been steadily declining and 20 10 surveys observed only one redd (pers. comm. Hans Berge, King County, November 22,2010). Steelhead occurring in the project action area are part of the Lake Washington winter-run population. They typically enter fresh water between November and April and spawn from late-March through early June. Survey data from 1984 though 1987 observed steel head in the lower reaches of May Creek (Newcastle 2002). Data from the WDFW Salmon Scape website (accessed November 22,2010) report that steelhead have been observed in the lower three miles of May Creek, with the nearest observation 0.75 mile downstream of the proposed project. 2.2.1 Critical Habitat Critical habitat has not been designated for the Puget Sound steelhead DPS. 3 ENVIRONMENTAL SETTING 3.1 May Creek Basin Overview The mouth of May Creek is located on Lake Washington approximately two miles north of the Cedar River in Renton, Washington. The May Creek Basin drains an area approximately 14 square miles west of the Cascade Foothills between Issaquah Creek, Coal Creek, and the Cedar River. The headwaters of the basin include Cougar Mountain, Squak Mountain, and the East Renton Plateau. The main stem of May Creek contains approximately seven river-miles of habitat and is fed by 13 primary tributaries. There are two lakes in the drainage, Lake Kathleen and Lake Boren that form the headwaters of the South Fork May Creek and Boren Creek, respectively. The northern portion of the basin includes Cougar Mountain Regional Wildland Park and some low-density residential development (City of Newcastle 2002). In the flat floodplain and wetlands of May Valley, the creek broadens and slowly flows through rural pastures, small commercial areas, and suburban development (King County 2001). Land use in the southern May Creek basin includes low and high-density single-family development, commercial development, forest lands, and meadows. 12 May Valley is largely composed of a natural floodplain that periodically filled with floodwaters even before this region was settled. May Valley was cleared and drained around the beginning of the last century, and has supported agricultural and residential uses ever since. Sediment eroded from streams in the Highlands and East Renton Plateau is gradually reducing the capacity of the May Creek channel in May Valley and until the I 990s, portions of the channel were maintained by landowners who removed sediment deposits and stands of choking vegetation (King County 2001). Analysis of past, existing, and forecast storm runoff and flooding conditions of the May Creek Basin indicate that flooding has increased significantly and will probably continue to increase as the basin is developed (KCSWM, 1995). As more development occurs throughout the basin, many of these problems are anticipated to worsen unless steps are taken to address these issues (King County 200 I). 3.2 Habitat Conditions at the Project Location 3.2.1 Aquatic Resources Aquatic resources directly impacted by the proposed project include May Creek and Long Marsh Creek. Stream surveys were conducted and the results are summarized below, additional detailed information can be found in the King County Baseline Stream Conditions Report (2010). . May Creek May Creek at the project location is dominated by slow water glides. The creek has two primary channel forms, which are influenced by the riparian plant community. In areas where willows are present and in contact with stream flow, the channel form appears to be mostly forced pool rime, with pools being forced by scour against channel-spanning willow branches or willow stems within the active channel. In areas where riparian vegetation consists of reed canarygrass or trees high on the banks, the channel form appears to be plane-bed. Both channel forms derive from past excavations and ditching for agriculture and sediment deposition. The channel gradient is flat throughout. Aquatic habitat is more complex in places where the riparian corridor has woody plants, such as willows, engaged with the stream channel and connected floodplain. Overhanging or rooted willow branches or stems provide cover and hard points necessary for bedform complexity, producing both turbulent and non-turbulent flow areas (King County 2010). Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel (Photos 1-5). Long Marsh Creek Long Marsh Creek is a tributary of May Creek that drains portions of the south side of Cougar Mountain. In-stream habitat below SE May Valley Road is somewhat shallow low-gradient rime with little to no pools. The stream is maintained in a relatively straight alignment by property owners to the streams confluence with May Creek (Photo 6). 13 ,-----,----------------------------- , :'1 ,'I ' Photo I. Looking upstream toward August 2010 Photo 3. May Creek looking downstream August 2010 Photo 5. May Creek channel 14 Photo 2. Looking upstream toward Red Bam February 20 I 0 Photo 4. May Creek looking downstream February 20 10 6. Long Marsh Creek, looking upstream from May Creek 3.2.2 Wetlands One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990), is located at the project location. This wetland is approximately 140 acres in total size, and approximately 25 acres of it is contained in the project study area that was delineated for this project (King County, 2010). The results ofthe delineation report are summarized below. May Creek #5 is a Category II riverine wetland with a 110 foot buffer, located in the natural I OO-year floodplain of May Creek. The wetland has been degraded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. On the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side of the wetland, the wetland boundary more closely follows the natural valley topography. While fairly degraded due to adjacent land use practices, it received a Category II rating due to its high potential and opportunity to provide flood storage and improve water quality along with its moderate potential to provide habitat to a variety of species. The hydrology source to the wetland is a combination of overbank flooding from May Creek and a high groundwater table. Numerous groundwater seeps were identified on the valley walls. The wetland is primarily palustrine emergent with some scrub- shrub/forested components that are concentrated near May Creek. The vegetation in this wetland has been degraded by the adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing, and therefore contain pasture grasses that could not be accurately identified given the season (late January) and regular mowing. In a majority of the wetland areas not regularly mowed, the dominant vegetation was reed canarygrass (Phalaris arundinacea), which grows in thick blankets with almost 100 percent coverage. The only unmowed areas without reed canarygrass were in the scrub-shrub/forested components ofthe wetland where the reed canarygrass was shaded out. 3.2.3 Geology The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The valley is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Formation. The formation is composed of volcanic tuff, fine- . grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop west of I 46 th and forms a physical boundary between the downstream ravine and May Valley upstream. The creek gradient within May Valley is 0.2 percent and the valley is predominately a depositional environment. Aerial photography and Lidar image of the valley show evidence of pre-dredging channel meanders. Historic survey mapping from 1872 show May Creek as a meandering stream and Tributary 0291 a extending north to join May Creek just south of Indian Meadows rather than the current confluence approximately 1440 feet west of I 64th Ave SE. The alluvial fans from Indian Meadows and Long Marsh Creeks appear on the 1872 map and the mapped location of May Creek 15 is routed to the southwest around the higher elevations of the Long Marsh/Indian Meadows alluvial fans. The historic channel map for 0291a is consistent with Lidar images showing meander scars in the valley. 4 EFFECTS OF ACTION 4.1 Direct Effects No direct effect on listed species will occur because these species are not present at the project location. Direct effects are analyzed below in Section 6 for the essential fish habitat consultation. 4.2 Indirect Effects Indirect effects are those impacts that are caused by the action and occur later in time (after the action is completed) but are still reasonably certain to occur. Indirect effects from modification of May Creek and Long Marsh Creek will result in long-term habitat alterations. These effects include temporary increases is stream temperature from riparian clearing and modification to sediment transport. A technical memo prepared by King County to assess sediment conditions in May Creek is provided in Appendix B and summarized below. The project proposes a number of features to reduce sedimentation to May Creek and channel filling. These include native plant buffers along the banks, removal and control of reed canarygrass, reduced overbank flooding, selected removal of vegetation from the channel downstream of 148 th Ave SE, and a sediment management design for Long Marsh Creek. These features are expected to produce the following effects: • • • • • • Adding plant buffers on either side of May Creek will locally reduce the amount of sediment reaching May Creek from rainfall runoff. Where reed canarygrass is present above the channel slopes, the grass is effective at catching and trapping sediment. Removal and control of reed canarygrass will slow channel narrowing and infilling due to growth during spring and summer during low flows. Reducing over bank flooding of pastures will reduce the amount of sediment and organic material being carried to the creek by an estimated 0.21 to 0.84 metric tons per year. Improved channel hydraulic efficiency will improve and move fine sediment and organic material that reaches the creek downstream, reducing the amount of sediment trapped in reed canary grass above 148 th Ave SE. The proposed alcove excavation and planting areas west of 148 th Ave will allow the creek to overflow into the alcoves during higher flows, this will slow the current velocities allowing sediment to drop out of suspension, but the actual amount of deposition is unknown. The May Creek channel is likely to be both a depositional area and a source of suspended sediment during higher flows. Soft muck in the stream bottom above the confluence with Long Marsh Creek is a combination of organic material from pasture runoff with mineral sediment. The muck builds up in the channel after rain storms 16 • A mitigation project in Long Marsh Creek will intercept gravel and large sand size sediment before it reaches May Creek. • Following bank stabilization with jute netting and seeding will reduce erosion and sediment input to May Creek. The May Creek Current and Future Conditions report (King County, 1995) identified the major sources of sediment to May Creek as coming from the ravine and tributaries below May Valley. The hydraulic analysis (King County, 20 lOa) shows that changes in flow velocity below I 43rd Ave SE will be negligible. Sediment movement is controlled by flow. Therefore, the same size sediments would be moved within the May Creek system. We estimate the project related reductions in sediment delivered to the creek primarily from reduced overbank flooding, will reduce the total fine sediment and organic muck in the stream. In general, fine sediment that does enter the creek as bedload or suspended sediment will move downstream due to improved channel efficiency rather than being stored in the creek channel above 148th, incorporated into the banks or moving though during large flow events. Some fine sediment or muck entering the creek will continue to be stored behind topographic highs and lows·in the channel above and below I 48 th Ave. At issue are the potential indirect effects of exposing adult, juvenile, and embryonic Chinook salmon to degraded water quality associated with sedimentation. Project activities will result in the removal of channel sediment and existing vegetation. Temporary impacts include sedimentation, loss of shade, and loss of organic detritus recruitment. Permanent beneficial effects include a net reduction in sedimentation and establishment of a riparian buffer planted with woody vegetation. Sedimentation and turbidity from land use activities can degrade salmonid habitat (Bash et aI., 200 I). Other impacts associated with elevated turbidity levels include behavioral modification, gill trauma, increased stress, reduced osmoregulation, modification of blood chemistry, reduced growth, reduced forage success, higher predation, redd damage, and lower reproduction. High levels of suspended solids may be fatal to salmon ids, while lower levels may cause chronic sub-lethal effects (Lloyd et aI., 1987). Juveniles and eggs appear to be more sensitive to sedimentation and turbidity than do adults (Lloyd et aI., 1987). Sedimentation and turbidity are normal occurrences in natural streams and can periodically reach relatively high levels. Depending on the time of year and location of the sediment discharge, increased turbidity could negatively affect an individual's ability to forage, seek shelter, and access cold-water refuge. The size of the sediment particles and flow velocities can affect the duration of sediment suspension in the water column. Larger particles (> 2mm), such as sand and gravel, typically settle rapidly, but silt and very fine sediment may be suspended for several hours. Suspended solids can potentially reduce light transmission and, if chronic, may suppress primary production negatively affecting the feeding success of juvenile Chinook. Sediment and turbidity also have the potential to modify adult migration and spawning. Limiting the in-water work to approved construction windows when few, if any, Chinook are present and the implementation, maintenance and monitoring of appropriate BMPs to reduce the risk of discharges of fine sediments will limit any potential impacts to Chinook. 17 Physical removal of muck (fine sediment) within the channel, maintaining topographic controls (i.e. bridge at 148'\ creating off-channel alcoves for deposition, and establishing riparian buffer with woody vegetation will reduce or eliminate the potential to introduce fine sediment into water containing listed species. By taking these protective measures it is unlikely that any life stage of Chinook will be negaiively impacted by sediment discharges from this project. Additionally, effects on steelhead are expected to be similar to those described above for Chinook. 4.3 Effects from Interrelated and Interdependent Actions An interdependent activity is an activity that has no independent utility apart from the proposed action. An interrelated activity is an action that is part of a larger action and depends on the larger action for its justification. No interrelated or interdependent actions will occur as a result of the proposed project action for Chinook, steelhead, or bull trout. 18 -------------------------------------- 5 CONCLUSIONS The determination of effects for protected fish species is contingent upon implementation of the previously identified impact minimization measures and mitigation. The proposed action may have the following impacts on Chinook and steelhead trout (Table 3): I) Modifications in sediment transport described in chapter 4.2 have the potential to indirectly impact fish within the project action area. • Preliminary assessments of sediment loading (Appendix B) indicate a net reduction in sediment loading resulting from the project • While some topographic controls will remain in place, removal of channel obstructions will allow sediment to pulse through during smaller flow events. 2) Temporary removal of riparian vegetation has the potential to indirectly disturb or harm fish within the project action area. • Temporary clearing of riparian vegetation will result in elevated summer stream temperatures. Based on post construction monitoring of similar activities, we anticipate elevated stream temperatures for approximately five years. Considering the information referenced in this report and project information provided in the construction plans, an effect determination of may affect is appropriate for Chinook and steelhead trout because: • Chinook presence has recently been documented downstream of the project within the action area. • Steelhead presence has historically been documented downstream of the project within the action area The project is not likely to adversely affect these species because: • The project is proposed to occur during the designated in-water work window (Augustl-31) when species, primarily Chinook, are least likely to be present. • These species are not present at the project location where direct impacts would occur. • Short-term water quality effects to listed species resulting from rewatering of the newly excavated channel will be discountable or insignificant. • Long-term water quality effects to listed species resulting from net reductions in sediment loading will be insignificant. • Short-term effects to species from elevated stream temperatures resulting from riparian clearing will be discountable and/or insignificant. 19 -------------------- • Permanent beneficial effects from mitigation elements will result in riparian, in- stream, and wetland improvements. • Potential impacts described above will be reduced through impact avoidance and minimization measures. Table 3: Summary of Project Effects on Species Protected Under the ESA Species Federal Status Life Stages Effect Determinations Considered Chinook Salmon (Oncorhynchus Threatened All freshwater May affect, not likely to adversely tshawytscha) phases affect Steelhead Trout (0. mykiss) Threatened All freshwater May affect, not likely to adversely phases affect Essential Fish Habitat May Creek Will adversely effect 20 6 MAGNUSON STEVENS FISHERYCONSERV A TION AND MANAGEMENT ACT Action Agency: King County Department of Natural Resources and Parks Project Name: May Creek Drainage Improvement Project (9AI205) 6.1 Essential Fish Habitat Background The Magnuson-Stevens Fishery Conservation and Management Act, as amended by the Sustainable Fisheries Act of 1996 (Public Law 104-267), requires federal agencies to consult with NOAA Fisheries on activities that may adversely affect essential fish habitat (EFH). The objective of this EFH assessment is to determine whether or not the proposed action(s) "may adversely affect" designated EFH for relevant commercially, federally- managed fisheries species within the proposed action area. It also describes conservation measures proposed to avoid, minimize, or otherwise offset potential adverse effects to designated EFH resulting from the proposed action. Pacific Coast Salmon NMFS has designated EFH for Pacific Coast salmon, including Chinook, coho and pink salmon, in Amendment 14 to the Pacific Coast Salmon Plan (NMFS 2000a). Within the action area, May Creek and Long Marsh Creek contain EFH for species present (Chinook and coho salmon). The Pacific salmon fishery EFH includes all those streams, lakes, ponds, wetlands, and other water bodies currently or historically accessible to salmon in Washington, Oregon, Idaho, and California, except above the impassable barriers identified by the PFMC (1999). Construction projects can significantly alter land surface, soil, vegetation, and hydrology, and can adversely impact salmon EFH through habitat loss or modification. Among numerous types of non-fishing activities that may affect EFH, should BMPs fail, those applicable to the action area are those that will: • Alter sediment delivery to, and quantity in, streams and estuaries; • Alter water flow, quantity, timing, or temperature; • Alter the amount or types of nutrients or prey. • Discharge pollutants, nutrients, or contaminants. 6.2 Description of the Proposed Action The proposed action, environmental baseline, and action area are described in Chapter 1.2, Description of Proposed Project Action; Chapter 1.4, Action Area; and Chapter 3, Environmental Setting of this BE. The action area includes Chinook and coho rearing and spawning habitat. Proposed project actions include: • Clearing, grubbing, grading, and dredging; • Work area isolation via stream bypass; • Habitat enhancement and creation, and site restoration; • Landscaping and planting. 21 ------------------ 6.3 Adverse Effects Essential Fish Habitat for Salmon ids The detennination of the effects of the proposed project on EFH is based on Section 305(b)(2) of the Magnuson-Stevens Act. Under this act, federal agencies are required to consult with NMFS regarding any of their actions or proposed actions authorized, funded, or undertaken that may "adversely affect" EFH. "Adverse effect" means any impact which reduces the quality and/or quantity of EFH. This can include direct (e.g., contamination, physical disruption), indirect (e.g., loss of prey, reduction in species' fecundity), site-specific, and habitat-wide impacts, including individual, cumulative, or synergistic consequences of actions. Project effects to ESA listed species are described in Section 4 and will also apply to coho in May Creek. In addition to those indirect effects, coho are present at the project location and will be directly impacted by the project action. Adverse effects from dredging of 2,000 linear feet of channel will result from an alteration in availability and quality of migration/rearing habitat for coho salmon in May Creek. Strict adherence to BMPs (see Section \.3) will minimize impacts to water quality in May Creek during project construction and proposed mitigation is designed to offset the operational impacts. Overall, there will be direct (coho) and indirect (coho and Chinook) effects upon Pacific Coast salmon EFH during project construction, but the proposed conservation measures and project BMPs will limit the scope and scale of the impacts, and no large-scale deleterious effects are expected to occur. 6.4 Essential Fish Habitat Conservation Measures Conservation measures will be implemented to minimize the potential adverse effects on designated EFH are described in Chapter 1.3 6.5 Conclusions Based on the EFH requirements of Pacific Coast salmon species, BMPs, and conservation measures proposed as part of the project, the detennination is that the project will adversely affect EFH for coho salmon. 22 7 REFERENCES Bash, J.e. Bennan, and S. Bolton. 2001. Effects of turbidity and suspended solids on salmonids. Center for Streamside Studies, University of Washington. Berge, Hans. Senior Fish Biologist, King County Water and Land Resources Division. 201 South Jackson Street, Seattle, Washington. Personal Communication on November 22, 2010. Bosworth, Aaron. Anadromous Fish Biologist, Washington Department ofFish and Wildlife. 16018 Mill Creek Boulevard, Mill Creek, Washington. Phone Conversation on November 15, 2010. City of Newcastle. 2002. City of Newcastle 2001 Stream Inventory. Prepared by Adolfson Associates Inc. for City of Newcastle, January 2002. Newcastle, Washington Federal Register, Vol. 72, No. 91 Friday, May 11,2007. Final rule. Endangered and Threatened Species: Final Listing Determination for Puget Sound Steelhead. Federal Register, Vol. 64, No. 147 Monday, August 2,1999. Final rule. Endangered and Threatened Wildlife and Plants; Listing of Nine Evolutionarily Significant Units of Chinook Salmon, Chum Salmon, Sockeye Salmon, and Steelhead. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Stonnwater Services Section, Capital Services Unit. King County and City of Renton. 200 I. Final Adopted May Creek Basin Action Plan. King County Surface Water Management Division and Renton Department of Public Works, April 2001. Seattle,Washington. King County. 2010. Baseline Stream Conditions May Creek Drainage Improvement Report. King County Water and Land Resources Division, March 20 10. Seattle, WA King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks. Prepared for Stonnwater Services Section, Capital Services Unit. King County. 2010b. May Creek Channel Restoration Project, Wetland Delineation Report. King County Water and Land Resources Division, March 2010. Seattle, WA Lloyd, D.S., J.P. Koenings, J.D. LaPerriere. 1987. Effects of turbidity in freshwaters of Alaska. North American Journal of Fisheries Management. 7: 18-33. 23 NMFS (National Marine Fisheries Service). 1999. Essential fish habitat consultation guidance. Office of Habitat Conservation. NMFS (National Marine Fisheries Service). 2000a. Appendix' A: Description and identification of essential fish habitat, adverse impacts, and recommended conservation measures for salmon. Amendment 14 to the Pacific Coast Salmon Plan. Pacific Fishery Management Council (January 1999). Available from the PSMFC Web site: http://www.pcouncil.org/ NMFS (National Marine Fisheries Service). 2000b. Magnuson-Stevens Fishery Conservation and Management Act and essential fish habitat. Available rrom NMFS Northwest Region Habitat Conservation Division Web site: http://www.nwr.noaa.govlhabcon/habweb/msa.htm. PFMC (Pacific Fishery Management Council). 1999. Appendix A: Description and identification of essential fish habitat, adverse impacts, and .recommended conservation measures for salmon. In: Amendment 14 to the Pacific Coast Salmon Plan. Available from PFMC Web site: http://www.pcouncil.org/ WDFW and Western Washington Treaty Indian Tribes. 1994. 1992 Washington State Salmon and Steelhead Stock Inventory (SASSI) Appendix One: North Puget Sound Volume. WDFW. 1998. 1998 Washington Salmonid Stock Inventory Bull Trout and Dolly Varden Appendix. WDFW, 20 I O. Salmonscape Interactive mapper -Salmon presence. Available at: http://wdfw.wa.gov/mapping/salmonscape/. Accessed on November 22,2010. 24 Appendix A Species Lists 25 Endangered Species Act Status of West Coast Salmon & Steelbead Sockeye S"lro"n (Oncori1yn"hllS """'klf) Chinook Salmon (O.l.Ihlm)"rsc1!aJ CoboSnlmon (0. /::isul"i.) Chum Sillmoo (O.l:cm) Slcclhe.ul (0. "'J-kits) 10 II " 13 " " 16 J7 " " " 21 " ~3 l~ " " 2S " 30 32 3J " J6 3; 3S " 40 'I " 43 .. " 46 " " " 'I (liJl/llrd JIl(r), lj"'~']'[~;c.~~ '" " , , The £S .... dciin~~ a "'pccic~" to iuehKl: any di~lincr population ~cpnau of ~lIy ~pccic~ of ... encbrat< fi<J\ or wildtit"!. For Pa~ific ~3111l"n. );,O.'oA Fi,betic; Scn;;ec cOlll.idn'\ nn C\'o\u!iou:uily ~i;nifican1 unit, or '-ESU.-a k\~:ie\~ 1m&.-me ESA. For Pacific \~clhtld. NOAA Fi,htti~ ~nicc ha, dcli.ucllfcd dil1im" POpul"tioll '~p1Icuh (DP~ • .I ill' cOlll.;,\mlliou ft, "~pc~ieo." u"dl:1 the ESA. 26 The project is located in T23N ROSE S02 & S03. Sections that Contain Natural Heritage Features Data Current as of November 5. 2010 Ust of surveyed land sections in Washington identified by the Natural Heritage Program as reported to contain Natural Herttage Features. Contact the Washington Natural Heritage Program at (360) 902·1667 for more detailed information on locations and occurrences. Town. Range Sec. T22N R35E 513 T22N R35E 523 T22N R35E S24 T:2N R35E 529 T22N R35E 530 T22N R35E 531 T22N R35E 532 T~2N R35E 533 T22N R36E 504 TZZN R37E S~6 T:::::?N R39E 519 T22N R3:;E S:::4 T22N R3SE 525 T22N R39E 5:::6 T:;::2N R39E 535 T22N R39E 836 T2:?N R40E 516 T22N R40E 517 T:::~N R40E 519 T22N R40E 8::0 T22H R40E 521 T22N R40E 529 T22N R40E 530 T22N R40E 531 T2~N R41E 501 T22N R41E 502 T22N RUE 503 T22N R41E 504 T22N R41E 507 T22N R41E 511 T22N R41E 512 T~2N R41E 513 T2~N R41E S14 T2:2N R41E s15 T22N R41E 516 T22N R41E 521 T22N R42E 503 T22N R4:?E 504 T22N R42E S05 T::2N R42E 506 T22N R42E 507 T22N R42E 508 T22N R42E 809 T22N R42E 513 T22N R42E 816 T22N R4ZE 517 T2:;:N R42E SIS T22N R42E 522 T22N R42E 524 T22N R44E 509 T23N ROlE 516 T23N ROIW S31 T23N ROIW 532 T23N R02W 501 Town. Range Sec. T23N R02w 814 T23N RO::'W S15 T23N R02W 816 T23N RO::'W 517 T23N R02W 820 T23N R02W 521 T23N R021'1 822 T23N R03W 503 T23N R03W 504 T23N R03W SO, T23N RO)W 510 T23N R03W s16 T23N R03W 835 T23N R03W 536 T23N ROSE 525 T23N R05E 536 T23N R05w S19 T23N R06E 510 T23N ROGE 511 T23N ROGE 531 T23N R06W 517 T23N R06W S2~ T23N R06W 830 T23N R07W S09 T:::3N R07W SID T23N R07W 511 T23N R07W 814 T23N R07W 515 T23N R07N 516 T23N R07W 521 T23N R07W 822 T::3N R07W 523 T23N ROBE 801 TZ3N ROBE 502 T23N Roaw 507 T.23N Roaw 813 T23N RO$W 814 T23N ROaw 515 T23N R08W 517 T23N ROSW SIS T23N Roaw 520 T.23N R08W 536 T23N R08W 539 T23N ROSW 846 T23N R09E 802 T23N R09E 503 T23N ROSIE 805 T23N R09E 506 T23N R09E 529 T23N ~09E 530 T23K R09W sao T23N R09W 506 T23N R09W S07 T23N R09W 518 Town. Range Sec. T23N R09w 519 T23N ROSW 520 T23N R09W 5':'; ,T23N R09W 82:6 T23N R09W 529 T2:3N ROSW 530 T23N R09W 53: Tz3N ROSW 832 T23N R09W 538 T23N ROSlW 540 T23N R09N s50 T23N RIOE 83: T23N RI0W 501 T23N R10W 502 T23N R10w 503 T23N RIOW 504 T23N RIOW 511 T23N RI0W 51::: T23N R10w 813 T23N RI0W S14 T23N R10W 536 T23N RIlE 515 T23N RIlE 535 T23N R12W S05 T23N P.l:::W 5::4 r23N R13W S02: T2.3N p.13W 503 T23N R13W S10 T23N R13w 511 T23N R14E Sal T23N R14E 511 T23N RI4E 812- T2:3N RI4E 826 T23N R14E 83S -r:3N RI4E 836 T23N RISE S13 T23N RISE 824 T23N RISE S26 T23N RISE 527 T23N RISE S32 T23N R15E S35 T23N RUE S10 T23N R16E 511 T23N RI6E 812 T23N R16E 813 T:::3N R16E 514 T23N Rl€E S15 T:::3N P.16E S"':' T23N R16E 823 T23N R16E S24 T23N RI6E 531 T23N RI6E 532 T23N RI7E SOl 'I'23N R17E 502 Washington Natural Heritage Program, POBox 47016. Olympia, WA 98504-7016 27 Town. Range Sec. T23N R17E 504 T23N RnE S12 T23N R17E 513 T23N Rl7E 5'27 T23N RISE S07 T23N RISE S08 T23N RISE 516 T23N R18E 817 T23N RISE 518 T23N RISE 819 T23N RISE s~o TZ3N RI8E 521 T23N RISE S22 T23N RISE 823 T23N RISE 5:6 T23N RISE S27 T:!3N R1SE 528 T23N RISE S29 T23N RISE 830 T23N R18E S31 T23N RISE 532 T23N RISE S33 T:BN RI8E S34' T23N R18E S35 T23N R19E 507 T23N RISE 818 T23N RISE 522 T23N R19E 827 T23N R19E 831 TZ3N R1~E 833 T23N RISE 534 T23N R20E S02 T23N R20E 503 T23N R20E S06 T23N R20E S10 T23N R20E 514 T23N P.20E S15 T23N R20E 831 T23N P.20E 532 T23N R21E 513 T23N R21E 514 T23N R21E S17 T23N R21E 52:0 T::!3N R21E S21 T23N P.21E s~3 T23N R21E 524 T23N P.21E 527 T23N R21E 528 T23N R21E 533 T23N R21E 534 T23N R22E 507 T23N R22E S'27 T23N R22E S28 T23N R22E 531 Appendix B May Creek Drainage Improvement Project-Plan Sheets 28 W1////!10 """"'" i22J SEDIMENT REYOVAL VEGETATION REMOVAL ALC~VES WORK, AREA ., WETLAND BUFFER (1'0') STREAM BUFFER (165') PlANTING MITIGATION LINE (15' BUFFER) EXISTING lEGEND ,TOE (BOTTOM), OF: STREAM ----DRIVEWAy'UNE FENCE ~ SURVEY CONTROL I :==~===. PROPERTY LINES R-O-W LINES DELINEATED WETl.A~D Stationing of the In Stream Willow Pruning for May Creek Station From Station To 0+00 0+30 0+70 1+50 3+00 4+50 4+90 5+40 7+50 9+80 10+20 15+00 -"'20'""0-------'0 200 SCALE IN FEEr '. / PROPOSED / :' TEI,4PORA'n' SOIL '-'2:-+?:~'-' / ,I'll DRYING AREA THE EXISTING TOP{)cr.(APHIC ANti PHYSICAL FEATURES SHOIt,!,: ON THIS PLAN ARE BASED ON.A COM8INAllO>i OF FIELD OBSERvATIONS AND LANi) SURVEY 9+00 -15+00 8'1': MEREDITH .RADELLA 29 WORK: REMOVE FLOw OBSTRUCTIN~ VEGETATlON AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFfER OF NAllV£ VEGETATION ON 88TH SIDES Of CHANNEL. ENHANCE OFF-CHANNEL WElL~ND F"1SH HABITAT-DO'l'l'NSTREAM OF i48TH S.E. SHEET: 2 OF 8 DAlE: FEB 3, 2011 MARSH CHEEK RESTORATION PLAN TO BE I"ROVICED IN ...s.gARA.TE PLAN SET ! ~~-700 0 200 SCALE IN FEET 5fOltJEkI ~EttOyAL D:OTE' REMOVE SELJI\.IENT fROM STA. 5+40 TO 7+50 ST:.._ 8+00 TO 26+26 'WOliK: "",,"_GE 1'I.?RCVEt.lENT FLOw 03STRUCn~G VEGETATION A:'>JJ SEDIMENT FROM ~A,Y C~EEK_ PLANT 15' BUFfER CF 1'\,:'.l1vE VECETATIQ.'J D;-'; BOTH SlOES Qf CH,ANNEL ENHANCE OFF-~HANNEL · .... ETLANi) FISH HABITAT DO\h'NSTREA\~ OF 14BTH S,L 15+00 -]9+00 VE:;;EDITH ii.A.DELLA 30 SHEET; .3 CF 8 DATE: FEE 3, 2Crd 10.00 5.00 Cf. 5.00 15.00 20.00 25.00 30.00 TYPICAL SECnON: SEDIMENT REMOVAL r = 10' 15.00 20.00 25.00 30.00 TYPICAL SECnON: VEGETAnON REMOVAL 1" = W' I ' IMPROVEMENT MEREDITH RADELLA 31 ""'".Fl·"'"N ANO SEDIMENT FROM MAY CREEK. PLANT 15' BUffER OF NAll\£ 'vLGElAllON ON BOTH SIDES OF CHANNEL. ENHANCE OFF-CHi\XJ\El ""'ETlAND FISH HABITAT DO .... 'NSTREAM OF 148rH S.E SHEET; 4 Of 8 OA 1E: FEB 3, 2m 1 • CHi'it,' ~'CT[; 5TA 0+00 TO 7';)0 ElEi~nON .:111.7 cc; 0"'.0 "'''M'~ ,'~ v", Tt,.'PICAL s:-c'nbl~".~' /'" " Y)\ '/'\." AT ALCOVE S AllONS >" SEE GRAVEL PECIFICi liONS T IS SHEE , I i 30100 2000 1000 10 00 20.00 3000 4000 50 00 60 00 6000 90 00 100.00 1 HABITAT ~ITIGAnON ALCOVE. GRADING ," = 20' HABITAT LOG ~ITIGATION PLACE~ENT ,. = ;0' LWD IN$TAl !,ADON NOTES- THE FOLLOWING METHODS OR COMBINATIONS THEREOf WILL 8E USED TO REDuCE ~OBIUTY OF lWO: • EMBED~ENT OF 50 PERCENT SURfACE AREA OF lOGS A.~D WILLOW ANCHOR POLES • TRENCH/BURY 60 PERCENT OF UDG LENGTH • PINNING OF LOGS AND ROQTV/ADS B8-lIND EXISTING TREES GREATER THAN 12" DIAMETER IN COMBINATION WITH PARnAL TRENCHING OF lOG PURPOSE: REDUCE DlJRATION OF FLOODING PRo,JEer 11M: ON PROPERTIES ADJACENT TO MAY CREEK: MAY CREEK DRAINAGE IMPROVEMENT BET'o\£[N APPRQX. RiVER MILE 4.3 AND 4.9. DIRECTIONS TO SITE: FROM COAL C:REEK PARKWAY, (EAST OF 1--'05) TURN EAST ON S.L MAY VALLEY ROAD, GO TO 148TH AVE S.E .• TJRN SOUTH TO BRIDGE OVER t.\A)' CREEK. DATUM: AS STATED SHEET ll1LE: 'SECTION VLEWS SCALL NOT TO SCALE ASSISTANCE !3Y: LINDSEy MILLER DRA .... 'N BY: MEREOITH RADELLA 32 RQPOSED WORK: RE~OVE FLOW OBSTRUCTING VEGETATlON AND SEDf!.4ENT F"RO!.4 MAY CHEEK. PLANT i5' BUrFER OF NATlV£ V£GETAnON ON 80TH SIDES OF CHANNEL ENHANCE OfF-CHA~NEL WETLAND FlSH HABITAT DOIA'NSTREAM OF 148TH Altl S.E. SHEET; 5 OF 8 DATE: FEB 3, 20;1 M IIIGAIIQ~ PI.!!:i ~QIES CONTINUED (8) PWlTlNG NOTES 1. MmGATION PLANTINC PLANS REPRESENT A CONCEPTUAL PLANT LAYOUT, All UrTICATION PlANTlNG PREPARATlON WILL BE DIRECTED IN THE FIELD BY THE ECOLOGIST. 2. PlANTING SHALL TAKE PLACE OURING THE DORMANT SEASON (NOVEMBER 1ST THROUCH FEBRUARY 26TH). PLANTING w.y BE ALLOWED AT OTHER TlMES AFTER REVIEW AND WRITTEN APPROVAL BY THE ECOLOGIST. 3. WITHIN THE FLOODPlAIN EXCAVATION AREAS AND All.. PLANTING AREAS WHERE REED CANAR'f GRASS HAS BEEN COMPLETELY REMOVED, PROVIDE AND INSTALL 4 INCHES OF COMPOST (PER SPEC) ROTOTlLLEO TO A (12) INCH MINIMUM. 4. IN ALL PLANTING AREAS WHERE REED CANARY GRASS IS PRESENT, FIRST MOW THE GRASS. COVER MOWED REED CANARYGRASS wITH CARDBOARD (OR A SIMILAR BARRIER MATERIAL AS APPROVED BY THE ECOLOGIST) FOllOWED BY 6 INCHES OF COMPOST. 5. PLANT SHRUBS AND TREES THROUGH THE CARDBOARD AND COMPOST AS DIRECTED BY THE ECOlOGIST. 6. ALL PLANTS SHALL BE NURSERY GROWN A MINIMUM OF ONE YEAR, PlANT hAATERIAL IS TO BE SUPPUED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PLANTS NATNE TO THE PACIFIC NORTHWEST, PLANT MATERIAL SUBSTlTUnONS ARE SUBJECT TO APPROVAl BY THE ECOLOGIST. 7. NO TACKIFlER, HERBICIDE, DR FERTlUZER SHALL 8E USED IN THE PLANTlNG AREAS, (e) GENERAL NOTES 1. TO ?REVENT REESTABLISHMENT OF INVASIVE VEGETATION, THE TOP 24 INCHES OF EXCAVATED SOIL IS NOT TO BE REUSED AS FILL ANYWHERE ON THE PRQJEcr SITE. 2. DO NOT DRrvE EQUIPMENT IN AREAS OF THE SITE WHERE COMPOST HAS BEEN MIXED INTO THE NATNE SOIL May Creek Riparian Buffer Planting, west & east of 148th Ave SE lOoOoOoO[ 0""'°0°0° Latin Name Common Name SiZe/Specmcations Quantity Trees --ft$d alder t" Caliper 0 6-8' Haight '" ~t 9' O.C, Pk_~ Sitka ~\,I(:. ~ {lal., $-6' Haighl Full o.r-FoIf~ "" PIc:am 9' O.C • .l'cpo1ro:~:pp. Black catt_d 15' .t_. taFt on, t· dlametar '" ......,. ~t 9' O.C, 1bJ9aphcu= Wnilm r.d ~ar !t {!CII •• 5-6' ~'ilht F,,' De..-ralia9'! ,.., Pli2>t g' O.C. SllrubSIWilJows """'-R~-a"" dlN;lwot>d Bllt. root. iIIlIl!mum 36" LDn{l -PIarlt l' O.C. -.. -PacifIC .. II" U .... Slokn. S' Lo~ 1/2-1" DiClrTHMr "" P\Qnt J' O.C, 54Ur~ Sitka *110 ... U .... Stck •• , 6' LDfI'i!, 1/2-1· DiorT>Gt_ "" ti Pml Y O.C, Klagc-ty PURPOSE; REDUCE DU~,l:.TlON OF flOODING PRO.IEer TITlE: ROPOSED WORK: ON PROPERTIES ADJACENT TO t.t.AY CREEK: MAY CREEK DRAINAGE II.',PROV£MENT REMOv[ FLOW OBSTRUCTlN::; 8ET~£EN APPROX. RIV£R MILE 4.3 AND 4.9. VEGETATlON AND SEDIMENT FROM ;)IRECTlONS TO sm:::: SHEET TlTLE: MAY CREEK. PLANT 15' BUFFER OF FROM COAL CREEK PARKWAY. (EAST OF PLANTING NOTES AND TABLE XATlYE VEGETATION ON BOTH SIDES 1-405) TURN EA.5T ON S.L MAY VALLEY OF CHANNEL ENHANCE ROAD. GO TO 148TH AVE S.L. TURN SOUTH OFF-CHANNEL 'HEllAND nSH 'TO BRIDGE OVER MAY CREEK. SCALE: NOT TO SCALE HABITA.T DOWNSTREAM OF 145TH AVE DATUM: AS STATED S.L ASSISTANCE BY: LINDSEY MILLER SHEET: 7 OF 6 DRA~ BY: II.EREOITH RADELLA DATE: FEB 3, 2ml 33 May Creek Alcoves & Wetland Enhancement. Planting Plan -west of 148th Avenue SE Latin Name I Common Name Size/Specifications Quantity Emergents -for alcoves near stream .ftmoI.:"fIffi= Common_ Pl:.lg (::>I:mt ,:;::" Q,C.} 500 ElIOCMri; palu.rITil Creeping rpib..wh Pl. .. " (Pknot ~:t O.C.; 500 C_mpam m-tc.k~<>e PI.Jii (?Iorrt ,2" O,C.) 5(}O 5hru bsfWiUows Comtt.; ~t:ri.r:w:f ~dogwood 8<lre rcC":, mi. " ICl19 125 PI:JIlt 3' O.C. Ph}~oc:arpus capftatus PacificcitaebMt BOf" (oct. rni. PII;r\~ 3' O.C. " lell'\! 100 --S\\~rtW. BtUd tOO~, mi, " long 175 Plan 3' D,C. Sptrnm dougfmii Dou",,_ 801'3 rcO., mi, 1"101",: !/ C.C Y len\l 175 Rubul" ~tDbilU ..,."",.,.", B<1h'J rc<)~. mi, " leng 150 PI(ll"'t 3' C,C. U~c:' 5t"~.n Salt! la.;iandm Paci:fie willow l.1i,;',,,,,,, 6' Lor>;;! Jj':-l" .10:1 tlklm<'Jl",r PI"rr:. 2' o.c. livoti St:lk~$ Stllix mthlmru .... willcw i.t..,i,'\uf't'". Ir LN''.l J/"-1· 300 Cromd'" Plan: 2' a.c. u~C' $'!.~k",~ s;a& la:iandm Pacific ",'inC!\\" ),I.,.,,,,,,, f' b. ~ 250 ~1~'ft'·'Jm !;/~· -1' <Jot1'~~rr Popuhc /ri('hocmpa """'''''''''''''''''' Ulo'f! pde c~.,:: tJr"".-urr, 5' I~"(l 250 M.,jmu", :VI,"-I" do~~e! tQ Kilgc:a..ty URPOSE: REDUCE DURATION OF FLOODING PROJECT TITLE: ROPOSED WORK: ON PROPERTIES ADJACENT TO MAY CREEK: ~AY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING BETvt£EN APPRQX. RIVER VILE 4.3 AND 4.9. VEGETAllON AND SEDIMENT FROf,A OlRECllONS TO SllE: SHEET l1llE: MAY CREEK. PLANT 15' BUffER OF FROM COAL CREEK PARKWAY, (EAST Of LOG AND PLANTING TABLES NAllY[ VEGETATION ON BOTH SIDES 1-405) TURN EAST ON S,L MAY VALLEY OF CHANNEL.. ENHANCE ROAD. GO TO 1481H AVE S.c. TURN SOUTH OFF-CHANNEL WETLAND F"lSH TO BRIDGE OVER MAY CREEK. NOT TO SCALE HABITAT DOWNSTREAJ.i OF 148TH AVI: DATUM; AS STATED SCALE: S.E. ASSISTANCE BY: UNDSEY fJ.lillR SHEET: 8 OF 8 DRAWN BY: MEREDITH RADELLA DAlE: FEB 3, 2011 34 --------------------- 35 ~ :3 ~ ~ J i .~ ~ Ii ~ Vi " , ...... : ...... , ... : . ' ~ , , ...... , .. :....... ., '\r· 36 ··!II: . I { . ..... ". ,_ .... /~ ... I I I ' I . ........ :.. f ··r··· .. ·· . I I I I i • -III i II , Appendix C May Creek Drainage Improvement Project-Sediment Assessment (Without Appendices) 37 tQ King County Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TIY Relay: 711 www.metrokc.gov February 9, 20 II TO: Doug Chin, Senior Engineer, Water and Land Resources Division, Department of Natural Resources and Parks FM: Julia Tumey, L.G., Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation and Jeff Burkey, Hydrologist, Water and Land Resources Division, Department of Natural Resources and Parks . RE: May Creek Drainage Improvement Project: SE May Valley Road and 148th Avenue SE -Sediment Assessment Introduction This memo provides information on sediment conditions in May Creek from approximately I 48 th Avenue SE upstream to I 64th Avenue SE. This evaluation addresses geomorphologic controls, sediment sources, sediment behavior in the drainage and how the project actions are likely to influence future sedimentation in May Valley. The purpose of the following background evaluation is to provide information to assist King County Department of Natural Resources and Parks, Water and Land Resources Division in the design process for a drainage improvement project in May Valley. The proposed project location is shown in Figure I. Two questions have been raised regarding sediment associated with the May Valley drainage improvement project: Question 1: Will the project change sediment delivery downstream to May Creek? Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? May C."eek Channel Restoration P."oject ProJ oct Vicinity • Study Area o Mile Markers Stream Incorporated Areas • Cougar Mountain Wildland Park • N -i- March 2010 t.i1 King County o 95 '90 390 510 lh ...................... ....,h ..... -..,. •• ..... c~ ..... _· ... IWJ .... _· ........ joot .. . _ ........ ..... ..... c....., ..... "., ........... ,_ ...... _ • ............. _..,.-"'-........... .... ,. ..... CII._w--.... _ .. -.......................... ....,. .. ....... ~c~ .......... IoIW. ... "' ...... ll,..w. _ ... " ........... N_ .... ~.M .. -.. .... ... ~I .... I_" .. t,..._ .. t""' .. ................. ' ......... ~ .... lIio_. ""I ............. , ................... "II .... ~ _,t._"',. ......... """c ...... Figure 1 Doug Chin February 9, 2011 Page 3 There are a number of factors that were not available for the assessment: • • • • The actual suspended sediment loads in May Creek in the project area, the suspended and bedloads from the tributaries and the relative contribution of sediment from different sources are not known. The change in sediment loading over time due to changes in land use in the basin; logging, development, agriculture and channel dredging is not known. All of the tributaries provide some amount of sediment to May Creek within the valley but the actual volume is not known. Long Marsh Creek delivers gravel to silt sized sediment to May Creek. A depositional area of gravel and sand is visible in May Creek. Estimates of the delivery rate for Long Marsh are made from surveyed elevation changes between a sediment-removal project in 2002 and 20 I O. Beaver dams above the project area trap sediment and release sediment periodically due to flooding or breaching. An assessment of the sediment behavior presented here is based on published basin information, aerial photo interpretation, survey data from 1965, 1979, 1993, 2002 and 20 I 0, a soil-loss analysis by Jeff Burkey, sediment samples from the May Creek channel, and May Creek survey records and studies conducted for the project. This assessment provides a working hypothesis about sediment movement in the valley and the basis for future investigations. Background Geology and Stream History The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The valley is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Formation. The formation is composed of volcanic tuff, fine- grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop west of I 46th and forms a physical boundary between the downstream ravine and May Valley upstream. The geologic map is shown on Figure 2. The creek gradient within May Valley is 0.2 percent and the valley is predominately a depositional environment. Aerial photography and Lidar image of the valley show evidence of pre- dredging channel meanders. Historic survey mapping from 1872 shows May Creek as a meandering stream and Tributary 0291 a extending north to join May Creek just south of Indian Meadows rather than the current confluence approximately 1,440 feet west of 164th Avenue SE. The alluvial fans from Indian Meadows and Long Marsh Creeks appear on the 1872 map and the mapped location of May Creek is routed to the southwest around the higher elevations of the Long MarshlIndian Meadows alluvial fans. The historic channel map for 0291 a is consistent with Lidar images showing meander scars in the valley. (Aerial photos and historic map information is located in Appendix A). May Creek was dredged to form a linear channel between 1910 and 1936 (Foster Wheeler, 1995). A description of May Creek by Bretz (1913) describes May Valley as a "swampy, wide bottomed old channel". A project plan dated 1935 (King County Map Vault) shows creek modifications extending from Lake Washington to I 64 th Avenue SE. May Creek, May Valley • Legend Qw-Wetland Deposits Organic Rich Sediment Qvr-Recessional Outwash Deposits Sand and Gravel Qvt-Vashon TIll Compacted Mix of Silt Sand and Gravel Tpt-Tukwila Formation-Mix of Volcanic and Sedimentary Material 1050 10 20 30 40 Mi les ------ N + Fig u re 2 tQ King County Doug Chin February 9, 20 II Page 5 Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited shrubs or trees. Periodic dredging is reported during the I 940s through 1960s (Foster Wheeler, 1995). Property owners may have removed sediment periodically. Sediment Sources to May Creek Agriculture and Pastures In the immediate area of the proposed project there are roughly 8.4 hectares of active animal pasture that abut the stream on both sides with a few animal access points to the stream water (assumed watering holes). Under existing conditions, these animal pasture areas are flooded at stream flows below mean annual flow rate (8.6cfs}----over-bank flooding begins approximately at 6 cfs at the low point in the bank. Thus, its likely sediments that may not have washed off during a rain event with overland flow will be washed off when the stream-system capacity is exceeded and floods overbank. After a flood event, there does not appear to be any visual deposition of sediments resulting from the stream itself and upstream conditions but erosion rills are present in the pastures. Thus, it is assumed that sediments suspended in the water column that flush into the pasture retreat back into the stream system. Given this condition with the added animal activity, sediments from soil disturbance would be additive to upstream sediment loads, thus increasing sediment loads downstream. The proposed project goal is to reduce frequency of pasture flooding, thus sediment loads, from a frequency of any appreciable storm to a near one-year storm frequency. To assess potential sediment loads from pastures in the project area, similar studies in the Green River watershed were evaluated (King County, 2007). The Green River studies have estimated sediment loads (via total suspended solids) ranging from 50 to 170 kg/ha/yr; residential = 158 kg/ha/yr, commercial = 172 kg/ha/yr, forest = 110 kg/ha/yr, and agriculture = 50 kg/ha/yr. Literature values (Burton and Pitt, 2002) are significantly different with 10,420,3, and 343 kg/ha/yr for residential, commercial, forest, and agriculture, respectively. Monitoring stations used for agriculture land use in the Green River watershed study were downstream of pasture lands in ditches that had significant amounts of choking vegetation in them just upstream of the sampling station. Given the relative position of the sampling location and the proximity of vegetation upstream, one may expect the Green River sediment loads to be lower than expected because of the vegetation trapping wash-off loads. Consequently, estimated loads from the May Valley pasture areas are then estimated in the range of 50 -340 kg/ha/yr (assumed 200 kg/ha/yr average). Simplistically if we estimate loads from the pasture lands to be 200 kg/ha/yr, and post-project loads are reduced in half, then for a ten-year period and 8.4 ha, there is a reduction of 8.4 metric tons of sediment contribution to May Creek. An estimated range would be a reduction of 2.1 to 8.4 metric tons of sediment contributed to May Creek. Doug Chin February 9, 20 II Page 6 Hydraulic model results estimate that the channel capacity to carry bedload and suspended sediment through the project area will be increased after the proposed project by increasing the channel efficiency. Velocities associated with lower flow rates are increased with the removal of vegetation choke points in the channel along with channel- bottom high points that otherwise create backwater conditions conducive to deposition, while depths are increased with a lower channel bottom in conjunction with more water kept in-channel rather than over bank because of improved flow-rate capacity. Reduced overbank flooding into reed canarygrass may allow the annual volume of fine sediment and muck moving downstream to increase on a yearly basis. Higher flow or flood events would continue to carry stored in-channel and off-channel fine sediment downstream in a larger pulse, rather then metering sediment at lower flows. The cumulative total volume of sediment over a longer time frame, ten years for example, would not be expected to change. May Creek bottom sediments were sampled by the King County Department of Transportation Materials Laboratory (King County, May 20 I 0 and October 20 I 0, Appendix B). In the area of I 461h Avenue SE the channel bottom is composed on sands and gravels, to well-graded gravel. Larger gravel, cobbles and occasional boulders are also present. In the relatively flat and low-gradient portions of May Valley in the area of 148 lh Avenue SE the hard channel is composed of silty-sand and sandy-silt. At the confluence with Long Marsh Creek the hard-channel bottom is composed of well-graded gravel. A variable layer of semi-liquid, organic rich mud (herein referred to as muck) is present within the stream channel behind constrictions in the channel (Figure 3). The muck was sampled 25 feet upstream of a private bridge at RM 4.6. A modified Loss on Ignition analysis (LOI) was performed on the sample and the organic content was approximately 28 percent. This is a very high percent organic material compared to King County streams (Burkey, personal communication). The exact source of this high organic content is unknown; however, the tributary stream channels within the project area do not contain the same muck material and the most likely sources are pastures, agricultural fields and grass/tree litter within and above the project limits. Sources of Stream Sediment Most of the major tributaries to May Valley enter May Creek upstream of 164lh or downstream of I 46 lh, outside of the project area. Froln just below 148 lh and 164lh four tributaries: an unnamed tributary (029Ia), Indian Meadows (0291), Long Marsh Creek (0289) and Greenes Creek (0288) enter May Creek. Small alluvial fans occurring at the base of Trib. 0291a and Indian Meadows identify where sediment is deposited at the valley floor. • A ditch carries Indian Meadows Creek to May Creek. The ditch carrying Indian Meadows has piles of sediment adjacent to the ditch. These appear to be hand dug sediment piles removed from Indian Meadows Creek (Bauman, personal ,------------------- Doug Chin February 9, 20 II Page 7 communication). Finer sand and silt reached May Creek and the confluence with May Creek is clogged with silt and reed canarygrass (GeoEngineers, 2008). • Tributary 0291a is shown on the 1872 map and before development of the valley flowing northwest parallel to May Creek, joining May Creek near the confluence with Indian Meadows. The stream now joins May Creek downstream of I 64 th and is hydraulically controlled by a culvert under SR-900. Sediment is primarily deposited upstream from the culvert (Foster Wheeler). The creek lacks a defined channel above the confluence with May Creek. • Greenes Creek enters May Creek west of I 48 th Street and currently does not contribute significant sediment to the project area because Greenes Creek discharges to a wetland and the confluence with May Creek is choked with reed canarygrass. Table I: Two year flow for May Creek Tributaries in the Project Area (Foster Wheeler, 1995. Drainage Unnamed Trib. 0291a 2 year flow in 23.8' cfs 'USGS StreamStats Estimate Indian Meadows 17 Long Marsh 42 Greenes 26 Within the project area, Long Marsh is one of the largest flow (Table I) and sediment inputs. The Long Marsh sediment deposits constrict flow and muck movement in May Creek. Long Marsh Creek joins May Creek south of May Valley Road near 150th Place NE. Aerial photography from 1936 shows the creek in a relatively straight channel. The current channel is on the order of two (2) feet wide and several inches in depth at winter low flow. The stream banks are approximately one foot in height, and the surrounding floodplain/fan surface is primarily planted in pasture grass. with some recent native plantings. Evidence was found of gravel deposition throughout this reach. Discussions with earlier property tenants indicate that sediment deposition extended into the adjacent pastures following a January 2009 storm event. Long Marsh Creek deposits form an alluvial fan composed of cobble-to silt-sized particles and discharge silt, sand and gravel into May Creek. May Creek channel bottom elevations are higher near the confluence and this channel fill is a choke point for flow within the channel. During high-flow events, Long Marsh carries large gravel-sized sediment to May Creek. Before Long Marsh was straightened, the stream would have migrated across the alluvial fan as sediment was deposited in the stream channel. As noted in the previous section, the Long Marsh and Indian Meadows alluvial fans built out into May Valley and forced May Creek around the fan. ,-------------------------------------------- Doug Chin February 9, 20 II Page 8 May Creek Channel Changes with Time Horizontal Boundaries Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited vegetation. Foster Wheeler measured the mean May Valley Creek channel width in 1995 as 20 to 25 feet, with wider sections up to 60 feet at RM 5.6 (Foster Wheeler, 1995). In March of2002 a stream survey was conducted between I 64th Avenue SE and I 48 th Avenue SE (O'Rollins, 2002) and measured the average channel width at ten to 14 feet. A stream survey was conducted in 20 I 0 (Thompson and Bauman), and the average wetted width of habitat units was approximately 12.1 feet and the widest wetted width was 23 feet (surveyed reach RM 4.35 to RM 4.87). While no change in average width occurred from 2002 to 2010, there is a possible pattern of channel narrowing between the 1936 and 1995 and comparison between the 2002 and 20 I 0 stream surveys. This is reflected in the available measurements; especially in areas dominated by reed canarygrass. The channel is still a relatively straight excavated ditch but grass, shrubs and trees have encroached into the channel. Survey data from 2002 and 20]0 surveys are also available. Cross sections of May Creek are shown in Figure 4 (cross section locations are shown in Figure 5). Five cross sections were chosen to compare the stream channel at relatively fixed locations in the stream. Upstream of the road bridge at I 48 th Avenue SE the channel is narrower and slightly shallower (Section B-B). Downstream of the bridge the channel is wider and more uniform in shape (Section A-A). The cross section at Long Marsh (Section 0-0) shows the 2002 bank deposits (right bank) associated with excavating sediment from May Creek (private property owner activity) and the filled-in 2002 channel profiie from Long Marsh Creek deposits. During the 2002 pilot excavation project in May Creek at the Long Marsh confluence, sediment was removed to approximately elevation 309. The left bank (looking upstream) has now filled in to 2002 elevations at the confluence but the rectangular channel shape is still present on the right bank. Upstream of Long Marsh Creek, the channel is approximately the same width but shallower. This may be due to where the survey staff was placed and the CAD program interpolating between points. Downstream of Long Marsh Creek the channel has narrowed. Survey locations varied slightly between center line, right bank or left bank and cross section elevations are approximate. s: • o· " ~ • , , "- " ~ • , £ ~ -" Elevatim (ft) w w W NO 0 ~ NO ~ 0 L g 1 .. 4 . 182 (68 xs -4.18._ -"---i"-:'SO\ < oi_' -'., -,,,. r .. ,. ..1 , ~'... \ 1 i L '. "~ I 4,265343 Downstream of Rodt~ir i • ~ -" •• , ,-j '., , __ ~.: i , I ,--, 4.3Z3418 ... ", I" .--" ~: ,.-,----'- I ~::::::::~:r1::~:~_-J__ t! ~-~~--- ; I ~ ~+4.353636 KG SUNe,t year 2010~ '...." ':..J\----~. o 4.3E9~1 KC SUiVey year 2010 t' o ~:387.:r5 KC Survey year 201f'~':" .. _, _. _ ~~ \. ,.. I'" N ~ 0 0 0 N ~ 0 0 0 .4.411OO3,,,j I _ . I ~::=_~:~~_~_~~:,.,:ear ~~r:~~~~----':";:----: ~~,--::. -_ .----: --,1- 4.455BIiQjettlt48h J -' i 4472884 KC Survey year altO (similar to OTA 3 t :=:KC~~",::'>1l_~ __ ~ ___ ': _ I I 455'''''' -------1--: ---~-----' -'\ ,I 4575:!l9KCSurveyyear2010. -I .------.---I-. .!. • \_. ··t- 4.6007J8._.L ...... _4.622613._.L. __ 4.640315 _1... -. I :,--I--.7 ;/ ,- ./ ,. '" " I ' I • , -I , "/ --1--/ 4.700732 KC Survey year :2010 (similar to OTAK X.. ~_ ~ I -I: ~ , I \. \ .. 1 .. :. . ... -: .. .4.7B8456KCSurveyyear:aJ10(similarlootakxs. _____ __ ~t 1 .4 749514 KC Survey year 2010 (similar to OTAK xs -1 i ~-.8~~~ ~c-~urv'~'~~r'-311i (s'im;':ar 10 ~t~; f. "" .. ~ i , 1 ~I Q, ~ ~ ~ I ~ m I " . ~ I C; , , -I '" 0 0 -1 , c. g-, Z § '" '" s: J! •• I'" ? •• I· ~ r~ "-0 , I ~ '" ,3 0 ; z I I .---1 -" I ~ 1 '" '" '" I 0 0 4861.,. ------~ . -----------!; ',-, I @ ! : ::: KC Surve,--y~r 2)10 (Slml~r~o Ola~ ~ .--_~_~{; ---. r ------- g 14937175 ____ _ _ _ _ -1 __ : _______ ~ ___ H. 'I I J .\ ~ I ---j 1'\ I I 4.949111 1~.c_.:>~~~ . .Y~r_.2010IJs.!m!~~.t??!~k.~ \ , .. ,1.... .... I· 4.9687.Z4 . :~ ') -4·~_~~·-:-::-::::-_:·-::-:::-·:::'--":T -. --_ -.-":' j _ _ .-... ~ 7·~:--",\-: ---1--· I ' 5.03891S otak xs 7'5l5::·.~ .............. J .. __ H' _ •• ___ ..... :.:-'_i::: .... :: ... ::~ .. : ...... _ .H -.~. "\\1"'-- 5.04 focttrict;le upstream ofCalasurdo property ..... :.____ I ~ \.5.097"'301" '" 7875:.1: gl:~::::-::~:~J~T_~,.-~: ___ .. ~ __ ." ! 5.185it17olakxsS315 .. · \ I .-.. ( ••• \ .. 1 , -r'''-' o .1 , ',I -~ \1-r , .. ! ! j I I .! .. --I "I 1 "'\ ~ 0 r 5::tllr~.3 -010 .... G !!! '", ,,>I g> lit ? I I ~ , '" 0 z ' ... '" '" '" N 0 0 -(£0[01: ',\JunO;) alI!)[ mOld) 0101: lI! SSOUJ(o!'U jU0llI!poS'pnW P"" U0!l£"~13 mOllOS: 10=4;) gU!M04S omold l(OOl;) h£W £ omg!d 6 og£d O! 01: '8 lOqmoooa lI!4;) gnoa Doug Chin February 9, 2011 Page 10 Channel Bottom Elevation Channel elevation surveys were conducted in 1965, 1979, 1993, 2002 and 20 I 0 (Data is located in Appendix C). A profile of May Creek channel from just below I 48 th Avenue SE to approximately 1,300 feet upstream of the confluence with Long Marsh Creek as shown in Figure 5. The figure compares the 2002 and 20 I 0 survey profiles and gives spot elevations at the I 48 th Avenue road bridge and at the horse-crossing bridge on parcel 0223059091, 15019 SE May Valley Road from 1965, 1979, and 1993. Upstream of Long Marsh, between 2002 and 20 I 0 the hard channel bottom is a foot lower in some areas and a foot to two feet higher in others. At the horse bridge the elevation has varied from 307 feet to 311 feet associated with sediment deposition from Long Marsh Creek. From station II +00 to 8+00 at I 48th A venue, the channel profile has flattened and the channel bottom has shall owed approximately three· feet. This area coincides with thick areas of reed canarygrass. Between 1965 and 2010, the 148 th Avenue road bridge channel profile has stayed relatively consistent at 307 to 308 feet. It appears from the elevation differences that where the muck and vegetation builds up, the channel bottom has also been aggrading. Changes in the bottom elevation should be considered approximate, perhaps within a foot of elevation change. Survey elevations have not been taken at the exact same locations and stationing is different between projects. Stream profiles in 2002 and 2010 (Figures 4 and 5) show thicker areas of muck build up behind higher elevations in the channel. Up to four feet of muck was measured above the Long Marsh Creek confluence in 2002 and three feet in 20 I O. Stream and elevation survey data indicates that soft muck present in the channel varies in thickness by location and with time. The muck thickness is variable and transitory, building up in the channel until higher flows in May Creek are able to move the sediment downstream. Muck and fine sediment is moved downstream by May Creek within the valley as bedload and suspended sediment. However, the valley and May Creek above May Valley is not the main source of sediment to Lake Washington. The May Creek Current and Future Conditions report (1995) identified the major source of sediment to the May Creek delta in Lake Washington as the May Creek canyon and eroding channels of tributaries that enter the mainstem downstream of May Valley. "'r---------,--------r------------------- I h~ n~ 1 320 3101·· -;'00 3101·· - --.- " SECTION A-A STA. 7+00 DOWNSTREAM OF 148TH ST j'D m ~ ,,,, ........ ~ .. lrLC>L "",L 1;; I j, . !lim SECTION B-B STA. 8+00 UPSTREAM OF 148TH ST 'n f2'\ ~ MAY CREEK CHANNEL RESTORA noN FIG. @] CROSS seCTIONS , /1'" 320 Z-010 I /~_ I """'" ~.,-= r " ......... p'o ~L L ok .b.oo SECTION C-C STA. 15+00 DOWNSTREAM OF LONG MARSH CREEK en m , ~ ~~~ "",L .1;; j j, .b.oo SECTION 0-0 STA. 16+00 LONG MARSH.CREEK (}[\ m ~ ,,~ ............. , .......... ";j7 SECTION E-E STA. 17+00 "'" """"'- " UPSTREAM OF LO~G MARSH CREEK ffi , .. ~ IIQlE! ALL CROSS SECTIONS ARE CREATED LEFT TO RIGHT LOOKING UPSTREAM. , f . • • ~ Is i I~ r- 18 I" I~ Ii' 18 r- I~ f" Is I- 18 I: ~ .~ 18 f- lo I" 18 I" 18 I; . ~ ~ ~ ~ .. ~ ~ = § ~ ~ 0' i § ;; • ~ 10 .,. , .. , ... ~ , 8 ···.·~r ........... . .. ; T>.J .. . >~! ..•........ ~ ••••. ·.·.· .•. ·.·.··.T .. I.~.I : ,,~ .: ... : ... : ... ~ , ., ...•.. 1 . ' I ... , ·.1 .. ....... } 'J'i. 8 8 • ; ~ 0' i .... ~ '-- '. , 8 ••• • Doug Chin February 9, 2011 Page 13 Findings: Project Features and Estimated Results Pre-project May Creek Sediment Sources and Channel Behavior above the May Creek Ravine: Based on field reviews of the project area, stream report (King County, 2010), a literature review of past reports on the May Creek basin, and a review of aerial photographs a qualitative estimate of sediment sources has been developed. Sediment entering the project area comes from: • Upstream May Creek (east of l64th ). Most of the major tributaries enter May Creek above the project and therefore will be a contributor to suspended sediment in the Creek. Six beaver dams are present or have been active in the past above the project area; two below 1 64th and four upstream of the project. • Long Marsh Creek is a contributor to channel fill by sand, gravel and small cobbles. The larger materials are able to reach May Creek during high flows due to the straight channel, slope and past channel maintenance by property owners. • Indian Meadows Creek is a minor drainage that is partially ditched through a pasture that reaches May Creek and contributes sediment to May Creek. • Tributaries (029lA, 0291) contribute minor but unknown amounts of fine sediment. • Stormwater runoff and pasture flooding contributes an estimated .2 to .8 metric tons of organic material and sediment to the stream. The May Creek channel is essentially a ditch, excavated in a historic wetland system prior to 1930. The gradient in May Valley is very low and the creek is only able to transport clay to sand sized sediment. • The May Creek channel stores organic muck/sediment from pastures behind relatively high spots in the channel bottom and releases it downstream to the ravine during higher flows. Muck then builds up again as flows recede and during rain events. Some of the muck contributes to aggrading the channel bottom as it is trapped and entrained by vegetation. The May Creek project proposes a number of features to reduce sedimentation to May Creek and channel filling. The 70% design plans include: • removal and control of reed canarygrass (Phalaris arundinacea); • native plant buffers along the banks; • reducing overbank flooding; • selected removal of vegetation from the channel downstream of I 48th Avenue SE; • excavated alcoves adjacent to the channel downstream of 148th Avenue SE, • a sediment management design for Long Marsh Creek, the primary source of sediment and channel constriction in the project area. These features are expected to produce the following results: • Removal and control of reed canarygrass will slow channel narrowing and infilling due to growt11 during spring and summer during low flows. Doug Chin February 9, 2011 Page 14 o o o o o o o Adding plant buffers on either side of May Creek will shade the banks where reed canary grass is present and help control grass growth and encroachment. Reducing over-bank flooding of pastures will reduce the amount of sediment and organic material being carried to the creek by an estimated .2 to 0.8 metric tons per year. Improved channel hydraulic efficiency will improve and move fine sediment and organic material that reaches the creek downstream, reducing the amount of sediment trapped in reed canary grass above I 48th A venue SE. The proposed alcove excavation and planting areas west of I 48th A venue SE wi II allow the creek to overflow into the alcoves during higher flows; this will slow the current velocities and minor amounts of sediment will drop out of suspension, but the amount of deposition is unknown. The May Creek channel is likely to be both a depositional area and a source of suspended sediment during higher flows. Soft muck in the stream bottom above the confluence with Long Marsh Creek is a combination of organic material from pasture runoff with mineral sediment. The muck builds up in the channel after rain storms and floods and is moved downstream during higher flows. Reducing flooding within the project area will help reduce the build up of muck in the channel. A mitigation project in Long Marsh Creek will intercept gravel and large sand-size sediment reaching May Creek. Bank stabilization with jute netting and seeding will reduce erosion and sediment input to May Creek after excavation. Estimated Changes in Sediment Transport and Channel Dimensions after Drainage Improvement Project: The proposed project elements and existing conditions were evaluated for how sediment would enter and move within the project area. Ifno change in behavior was expected, the conditions were assumed to remain the same and are listed below as "constant". If the project element was expected to modify sediment behavior by qualitatively reducing the amount of sediment reaching May Creek, a reduction is noted in the bulleted list below. During construction, temporary increases in sediment are possible and this is noted. o Constant Upstream May Creek (east of I 64 th). Most of the major tributaries enter May Creek above the project and therefore will continue to be a contributor to fine sediment in the Creek. Beaver dams will hold back sediment and periodically release it when breached. o Constant Tributaries (0291A, 0291 and Indian Meadows Creek) contribute unknown amounts of fine sediment. These are expected to be minor. o Reduction Small proposed mitigation alcoves downstream from I 48th will allow sediment to deposit at higher flows. o Reduction Long Marsh Creek mitigation project will minimize course sediment reaching May Creek and channel infilling. o Reduction Reduced pasture flooding will reduce the organic material and sediment discharged to the stream, estimated at .2 to .8 metric tons. Doug Chin February 9, 2011 Page IS • Reduction Reduce channel narrowing by controlling reed canarygrass along the banks by establishing a buffer of plants on either side ofthe channel and shading the banks. • Temporary Increase Channel excavation will temporarily expose "raw" bank and channel sediments to the channel. Jute matting and bank planting will control erosion but minor erosion within the channel may occur as the channel stabilizes. • Change in fine sediment movement Fine mineral and organic sediments that reach May Creek and are now stored in the stream channel or trapped by grass during low flows will move downstream during lower flows. Fine sediment and organic material currently stored in the channel and moved downstream during high-flow events, will move downstream at a constant rate rather than episodic rate. The overall estimate is a net reduction in fine sediment and organic material reaching May Creek within the project area. Long Marsh Creek mitigation, the mitigation alcoves, reduced flooding, and reed canary grass control are project features that decrease sediment contributions to May Creek in the project area. Controlling willow and reed canarygrass will control channel narrowing. .. . Responses to Questions on Project Performance Question 1: Will the project change sediment delivery downstream to May Creek? Response: The May Creek Current and Future Conditions report (Foster Wheeler, 1995) identified the major sources of sediment to May Creek as coming from the ravine and tributaries below May Valley. The hydraulic analysis (King County, 20 I Oa) shows that changes in flow velocity below 143rd Avenue SE are negligible. Sediment movement is controlled by flow. Therefore, the same size sediments would be moved within the May Creek system. Muck sediments are currently stored behind topographic highs in the stream channel and are moved downstream in pulses during high flow events. In general fine sediment that does enter the creek as bedload or suspended sediment will move downstream due to improved channel efficiency rather than being stored in the creek channel above 148th, incorporated into the banks and moving though during large flow events. However, some fine sediment or muck that does enter the creek will continue to be stored behind topographic highs in the channel or in topographic lows above and below 148 th Avenue. We estimate the project-related reductions in sediment delivered to the creek primarily from reduced overbank flooding, will reduce the total fine sediment and organic muck in the stream. Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? Response: We estimate that there will be an overall reduction in sediment contributions to May Creek within the project area. The stream channel bottom elevation is relatively stable, except where Long Marsh Creek discharges to May Creek and where reed cannarygrass and muck aggrades the channel. Reducing sediment and organic matter input to the channel from Long Marsh Creek and the pastures and removing reed .----------------------------- ---- Doug Chin February 9, 20 II Page 16 canarygrass will slow narrowing of the channel. Active monitoring and buffer-planting management along the creek banks will take place for ten years to allow establishment of native vegetation buffers. The larger channel can be expected to last beyond ten years. This assessment is based on qualitative analysis with available information. Quantitative sediment estimates are not available. Doug Chin February 9, 20 II Page 17 References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. Booth, D.B., Haugerud, R.A., and Sacket, 1. Geologic map of King County, Washington: scale I: I 00,000. Bretz, J. Harlen, 1913, Glaciation ofPuget Sound Region, Bulletin 8, Washington Geological Survey, 244p. Burton, G. Allen, and Robert Pitt. 2002. Stormwater Effects Handbook: A Toolbox for Watershed Managers, Scientists, and Engineers. Lewis Publishers, Boca Raton, Florida. http://www.epa.gov/ednnrmrl/publications/books/handbook/toc.pdf Foster Wheeler, 1995. See King County, 1995 below. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. Hart Crowser, 2009, Final Site Investigation Report, Loon Lake, Washington, prepared for the Washington Department of Natural Resources, 117 p. Access online September 2010 at: http://www.dnr.wa.govlPublications/aqr loon lake final invest report.pdf Horner, Richard R., Joseph J. Skupien, Eric H. Livingston, and H. Earl Shaver. 1994. Fundamentals of Urban Runoff Management: Technical and Institutional Issues. Prepared by the Terrene Institute, Washington, DC, in cooperation with the U.S. Environmental Protection Agency. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Storrnwater Services Section, Capital Services Unit. King County. April 200 I, May Creek Basin Action Plan. King County Department of Natural Resources, Water and Land Resources Division. King County 2007. Water Quality Statistical and Pollutant Loadings Analysis -Green- Duwamish Watershed Water Quality Assessment. Prepared by Herrera Doug Chin February 9, 2011 Page 18 Environmental Consultants, Inc. http://green.kingcounty.gov/WLRlWaterres/StreamsDataireports/green- duwamish-Ioading-report.aspx King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. 2010b. King County GIS Center LIDAR, Topography, Geology, and Stream Location Layers, viewed with ARCGIS http://www5.kingcountv.gov/gisdataportal/ King County. 2010c. Particle Size Evaluation of May Creek Water Channel Soils, Job Number 1 B 1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, W A. King County. 2010d. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, W A. King County. 201Oe. May Creek Drainage Improvement Project 70% Design Progress Plans dated 10-22-10. . King County. 2010f. Baseline Stream Conditions May Creek Drainage Improvements, CIP#9AI205. NCRS 1993. Soil Survey Division Staff. Soil survey manual. Soil Conservation Service. Us. Department of Agriculture Handbook 18. http://soils.usda.gov/technical/manuall Yount, J.e. and Glower, H.D., 1991 Bedrock Geologic Map of the Seattle 30' by 60' Quadrangle, Washington: U.S. Geological Survey, Open-File Report OF-91-147, scale I: I 000000. II II • II II II JA JORDAN I AVENT a. ASSOCIATES Remarks: r1ay Creek Study Page 7 Remarks included any supplemental information which mi9ht help to describe the segment or subcatchment. Land use for each subcatchment was entered in this column. Other comments included: Street names to aid in locatinq culverts, clarification of inflow of one segment into another, or the existence of storm sewers or curbs. Please note that streets in this area have changed their names and numbers several times. flames or numbers listed under remarks are those taken from street siqns. \ PROBLn1 AREAS The second objective of this study was to photograph and briefly comment on areas subject to serious flooding, erosion or sedimentation. Forty-eiqht color slides and their descriptions are included in Appendix 1. Flooding The problem of flooding along Hay Creek has been a subject of local concern for several y~ars. Harstad and Associates were contracted in 1965 to plan-flood control correctives. Their solution was channelization. This plan was never carried out, m~nly for financial reasons. Flooding and high water tables are problems in a 170,000 foot reach of middle and uppper May Creek. More specifically, this area begins about 2,500 feet abOve the Highway 900 bridge over nay Creek, High water problems also exist in the valley which extends southeast toward Issaquah. In this valley-pondinq is a frequent problem from May Creek almost to the basin divide, a distance of about 3,400 feet. The cause of flooding in this section of the valley _is simple:-low channel gradient. Flooding problems end where the channel slope again increases, i.e., about 800 feet below the 143th Avenue bridge. Seasonal high water presents a G-7 I I, I I I I I I I I I I I I I I I I I I' , , I , I: I' , , I I, I I: Ii I, I, I I I I I " .',.' . . , ... ·1' .. •• Q I!ilil ~~~ I~IJ ~!! . '-. . , ". :," .. .. '."'.'. :. '., :". ,-, ' .. :., .. , i·"',' • 1 ,1 H \ i II ,; , ti . i 11 i ~i' ~ ~ .. 1 ·~l l~ " • " .' . ',: , .... ': '" T :., ...... , .1'</' •• ;','_,.' ~.:.:: ··I)(a,(.I~ - , .': ~ \ " ® - -:--.Ir : - -,-- L-Illir! ~ - -·1 - -, - I I ! i _ . ...;, ~ Iii' jJ J I .,~ ~ 4 I I 1 , !!= --"':1 , 44 :::;;... ... • II ',; >-~ ~ I ; .-1-' I' - -= \., Ill- " lJ II : rr 1111 1-<' a '" :: . it -- - 1 ..., ; I Iii L... . 1"'-. ~:l I~I) ~t ------------ , .. : '. -'.'.:" . ---... 1411. ~ j )L ,61. I Is • • i I J, ~ I r :-ltat" ~ ~ . (- ~. ' .. ~~ "" ,) , I, ~ " I I I I I I I I, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I - ;' . -"L *," 011 I I I I I I I ~ m g m n ~ ~ ~ § Z ~ 0 . 8 0 6~ m < < .. ~ ~ m < < ~~ ~ m m m ~ ~ ;; ;; ~g m ~ ~ ~ ~ 0 ~ ~ 0 8 0 ~ ~ Z 0 8 g 0 0 o 0 FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS ELEVATION (FEET NQVO) "' ' ...J,~~, , -~:H-' . - ~H ." FLOOD PROFILES MAY CREEK , i , I I ,11 __________ ..... -.-II .... -I--I--I----J-L--L..II!!!!!L... Q 340 335 . ~,. I· ~4 ::~·:t;: ~.!:p-;:;:Trcc'~· , 4;: ,,-;rr:"7!.i'lli"i~" .- ".t]r'" .'; ,.' 'r' .. ' .. '.' .... 1:1. r.,r. ..• l+++r++-L~~:--; .-C-l'~ 1 1 + . ;m""!"~' . t~~~·i(~mJ.iI·t-R.'~ ., .. ~ ~S-GGf tffi ' : .. ' ;.1-.,.-_ ..•. :' NGiOE) .' . . 1'1 i;.:,:;r '.1+' If.:fj· ~-: •• _L -I .• , t- 0-' I' . ' .......... . , \'It:t1HiH z ~~~~~~~~~~~~~~~~~~~~~~~~~~~tt~~rt~It~ o ~ ~ 320 ~ w 315 ____ ~P.~ .~ ~~,;f ~Ll~+lr -1·-1 :;1:; ••• 6.7 6.8 '.9 •. 0 •. 1 '.2 •. 3 I II "."," oj.! 1- fijI •. 4 ••• 1.1 ~ LEGEND ~ 6 ..7 500 • YEAR FLOOD 100· YEAR fLOOD 50· YEAR fLOOD 10 . YEAR FLOOD STREAMBED CROSS SECTION LOCATION ••• :~; ~ I STREAM DISTANCE IN,MILES ABOVE MOUTH ,,~ 'L. _______________________________ _ ,\,' 340 33 • 330 32. 320 31. 310 •. 9 '" ... ~ ... .,. "" ... CI .,. .,. ~ ... > y • w " < ~ z i >-~ '" ~ ~ -=I: 0:: w ~"" " c < -... • >-1-~ !i?~ > :> c:> ~ eta.. w c.> a: " '" c:> ffi z:: 0 ~ 52!: ~ li! < "' "" w c w ~ IJ:IP I I I I I I I I I I I I I I I I I --'" .... w o ~ FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS ELEVATION ~FEET NGVD) + .Ij I:n",~1-RIDG , . " ., FLOOD PROFILES MAY CREEK - "~ ----------------300 CTTTTrn~~~ ,++++H I!+H ,+, I,. ,.1 ,. ,I I, • T' ~'!: : ! . " I' I .l I t L.j -r ... 'in 295 1 , I P, ,I" i ~~ r : ~ ll-~t;.. I t ~ ! i . ~ql ·"-i' i~ "~+I r±±±-+t±ti-T1f+L2-R+fri..;.lJ.f.4.1:'ffi" ,~j • ' • • • i ~ -!l . At i .--~:~~:. -:- __ I. ~(_l i1r !~ ~:, , .1; t -I [., 1--, i' . -dW la.' _"1 fflmoom J!lw+!t~ ~ : : I : ~ I I . I ": I , I ,I _ ~ . ,: ". j .r.t'. 'i' '.' tt [11-"'" --, ',W"'" '''' ./ . . . ., , ! tl.: en tJ " ::J,' 1 I .M'7 ~f-fl9&--315 ---~--~nr!'-tl "B" . 'ti:':;~T;-i-+l ~l-t11I~ 315 -.T.UT~=L .,"'h+-r--, --.-. j,: •. r -0' . ;:: : . , 'H'-~. '=r-:'~ "-' .. . , 30!; ;--: 1 ....,.:.: +~_.;. 310 \;; . dJ!Hi I ' . " .... -....... ,-, -;; . ' . . "1 . I ' . +-~r rHHft ## .1. i. . , ., : ,-i-+-1..." r ;·t 1275 rmlJLriH:-~E~rw .!-I I .\; . t'I' .. ,-1'·0 -->0'1---.1 :#/0, .,.: ;:cqH~*;iimnJr ::"1;::1.. " , .-, ' ••• "I 270 .;. t ~ t't..,.-i-.: !. , . ' , i .. 1. _. 1 .. ~, . :.Ll'·! ... _: .. __ .:,;::. !:U: i. 260 "1~"';'-i i_.~_,: I'!'· . l ' . , _. I · , · " . " I I -~ I ~.L>:· ._;.~ , 265 L'F!' ,'Tn i-~ : ; • -. ~!., ; i _!-"I-" I }I{~f:T: .-,-.. . ~ . -; L: '-~! L:.; • -! •• ,.;. , • .-! ... .~.: .' . AA . , ; . :l~ 1 ; AS" 3. , 3.2 3.3 3.4 3.5 3.6 3.6 ; : : :' ( 'i t -~ - ._1 •. -i.. • ; ! ; I : . . : r ~ . ~ .. .'.j. , 1 !~. -..:../-- :', (' ',., ,,-.. , . -. 3.7 ., _. 11 3 .• STREAM DISTANCE IN MilES ABOVE MOUTH 29O 500· YEAR FLOOD ------100· YEAR FLOOD -----50· YEAR FLOOD -------10· YEAR FLOOD ~ STREAM BeD 6 GROSS SECTION LOCATION 3.9 4.0 4.1 4.2 4.3 - V) ... ..... ... "" ... "" ... ... '" ... 0 >-.,. "" "'" ::E "'" ..... ... > u Z w u en < ~ "" z ... w ",,'" I ~ ;=< 0 c < -... :i >-0-t-"" ~ z", > ~o u 00. z 0", w ",0 ~ : zo w -z ~ '" -w C> ~ z < co: : w 0 w • l11P I I I I II I I I I I I I I I I I I I I I --'" ,. .. -':\J~"-~f,~j_j '.' ., ELEVATION (FEET NGVDI .,. 01 I I I I I /' I I I :;; Q m n ~ ; IS 8 § z " ~ c o~ " :.: :.: m .... ~ m m ~~ > > m m ::jm " " > > i~ ~ ... ... " " c 8 ~ ... ... !1 0 ~ ~ 0 o 0 c c o c c c fEDERAL EMERGENCY MANAGEMENT AGENCY FLOOD PROFILES KING COUNTY, WA AND INCORPORATED AREAS MAY CREEK r 00 , " C ~'j .:$: .. ' h ' , ' !~: ll::::: ' t~'~,· , 1 ", .; ; o ... ew-' :[.,' L I , o '. f-l- ,lol! I I I I I I I g ~ ;:; s ... § ~~ " ' , 8 § 1'1'10(0(" W ,. m ,., -< 0( "'s,.,.;:> ~ § ~ ~ :,: :D, :II i 0"''''''' "II !il 8 8§ § C C' C c :. ;; ia: ~ m " m Z " " 1~ ":" , ,-'-' ~ 0 • 0 FEDERAl. EMERGENCY MANAGEMENT AGENCY ~ KING COUNTY, WA .... AND INCORPORATED AREAS , ..... ~. .\ ,,' .... . ELEVATION (FEET NOVO I .. o FLOOD PROFILES MAY CREEK ~ 0 , ",r' .: .::!-=' .I ~ 0 I ,', I g I I I I I I I I I I I I I I I 8 I I -- -- -- -- ---- - - - n°, !S·i+&#}:ckii<Wi xL -1 -O'OW' .: ! -nt-e--ya-r ........ -r-r --e= • , I FLOODING SOURCE FLOODWAY BASE FLOOD WATER SURFACE ELEVATION iECTlON MEAN RHiUlATORY WITHQUrol I WITH (11055 \1 CflON GlSJAHCl I WIDTH ARlA VELOCITy flOODWAY fLOODWAY "Ul, (SQUAll (fEET PER fEU, SECOND) IfEETNGVDI • • Hay Creek Tributary A 700 61 127 1.1 329.5 328.0 329.0 B 1,100 78 198 0.7 329.5 328.1 329.1 C 1,600 69 151 0.3 329.5 328.2 329.2 D 1,950 45 92 0.5 329.5 328.2 329.2 E 2,420 51 96 0.5 329.5 328.3 329.3 F 2,760 13 22 2.1 329.5 328.5 329.4 IFeet Above Houth 2Elevations Computed Without Consideration of Backwater from Hay Creek , FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPOltATED AREAS FLOODWAY DATA MAY CREEK TRIBUTARY , --=.',,\f--"";t'..~ lNCRfASf. 1.0 1.0 • - 1.0 1.0 1.0 0.9 T A B L E FLOODING SOURCE (ROssuetloN DISTANCE 1 W1DtH (fEn) May Creek (Cont'd) <;12. qo~) BA 6.56 13 BB J\1;'11 6.65 138 Sf JA.A 'f ~,f(It8'C 6.70 11 BD 6.76 34 'BE 6.93 61 BF 7.10 33 BG 7.24 11 IMi1es Above Mouth. FEDERAL EMERGENCY MANAGEMENT AGENCY. KING COI)NTY, WA AND INCORPORATED AREAS \ FlOODWAY SECTION ARE.A (SQUARE fEET) 40 106 26 58 48 37 26 BASE FLOOD WATER SURFACE ELEVATION . ".' MEAN RtGULAI0RY WITHOUt I "('!!' INCIUASE VELOCITY 'lOODWAY flOODWAY IfEn PER SECOND' (fElT NGVO, 6.0 324.3 324.3 325.3 1.0 2.3 329.5 329.5 329.5 0.0 4.3 330.8 330.8 331.4 0.6 1.9 332.0 332.0 332.8 0.8 2.3 334.1 334.1 335.1 1.0 2.9 338.1 338.1 338.8 0.7 4.2 341.9 341.9 342.7 0.8 . FLOODWA Y DATA MAY CREEK - - --------------.:...:..::'~.: , ......... ".. .... . . FLOODING SOURCE ,Pl.OUUCTlON May Creek (Cont'd) OISTANC[1 AA 3.23 AB 3.34 AC 3.49 AD 3.68 ~\-:1' ~AE ~.74 .c-~ AF WfS'" I, 3 • BO \140 ..... EIK.JAG ,L< 3.90 AH' (0.11';") 3.99 ,;K"" a.) AI q£ ~. , ~q[ , AJ G" 4.13 AK -1 b-lJ 4 22 AL (1.+"':') r}::l! 4.37 '" AM I'? ".I 4.48 AN 1~2-' £<4,'4.58\t I. I AO 4.68' %Z40, AP -~ AQ 15.12 ! ~,AR 41 1 ( 5.30 .~ 1(4-fP, I. 5.47 £,b"-< i If ,orK ! AT AU AV ~1.0l""') AW ~ t;-W! AZ 1Miles 'Abo~e Mouth 5.56 5.72 5.86 6.00 6.16 6.29 6.44 -V (-:.gq~) !?k~ CSG WIDTH (fEn) 37 33 41 40 15 21 18 53 19 92 75 231 96 137 19 133 115 44 12 73 85 184 216 50 100 170 T A B l E FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS 4 • fLOODWAY SECtiON .Rt. (SQUARE FEEl) 124 78 135 134 78 80 105 257 92 371 303 983 387 540 78 559 325 120 57 413 444 743 491 70 271 324 MEAN VUOCIT't (fEn PER UCOND) 5.1 8.2 4.7 4.B 8.2 8.0 5.3 2.2 5.5 1.4 1.7 0.5 1.3 0.9 6.5 0.9 1.6 4.2 6.5 0.9 0.8 0.5 0.8 5.3 1.4 1.1 REGULATORY 266.4 278.3 289.6 300.3 304.3 306.5 309.2 310.0 3:0.2 311.5 311.5 311.8 311.9 312.1 '312.5 313.4 313.8 315.5 319.2 320.3 320.3 320.4 320.4 321.9 323.2 324.0 .. __ .-._ .. '-'-.. -------.-. BASE fLOOD WATER SURfACE ELEVATION WITHOUT I -WITH FlOOOWAV •. ---.•.• (FEET NGVO) 266.4 278.3 289.6 300.3 304.3 306.5 309.2 310.0 310:2 311.5 311.5 311.8 311.9 312.1 312.5 313.4 313.8 315.5 319.2 320.3 320.3 320.4 320.4 321.9 323.2 324.0 267.3 278.3 290.2 300.3 304.5 306.9 310.0 310.7 311.1 312.1 312.3 312.8 312.9 313.1 313.1 314.4 314.8 316.0 319.2 321.1 321.2 321.4 321.4 322.2 324.2 324.8 FLOODWAY DATA MAY CREEK - ---eNdS = 'J INCREASE 0.9 0.0 0.6 0.0 0.2 0.4 0.8 0.7 0.9 0.6 0.8 1.0 1.0 1.0 0.6 1.0 1.0 0.5 0.0 0.8 0.9 1.0 1.0 0.3 1.0 0.8 \ T A B l E FLOODING SO,URCE (ROSS SECTION May Creek A B C D E F G H I J K L M N o p Q R S T U V W X Y Z I MilesAbove Mouth DIHANCE' 0.14. 0.16 0.24 0.2~ 0.31 0.39 0.46 0.52 0.57 0.63 0.78 0.94 1.09 1.2~ 1.36 1.39 1.41 1.42 1.46 1.54 1.56 1.61 1. 74 1.83 1.96 2.02 WIDTH CfEU) 34 60 42 42 31 40 28 23 45 31 33 79 33 39 32 40 33 33 30 22 8 43 27 38 ~2 42 FEDERAL EMERGENCY ~ANAGEMENT AGENCY KING COUNTY, WA AND INCORPORATED AREAS FLOODWAY SECTION .... (SQUARE fEET) 158 239 99 110 121 1~0 87 123 165 89 133 143 113 128 89 172 90 111 95 91 68 283 81 170 101 130 MEAN VELOCITY (fEET PER SECOND) ~.~ 3.6 8.8 7.9 7.2 ~.8 10.0 7.1 ~.3 9.7 6.~ 6.1 7.7 6.6 9.6 4.9 9.5 7.7 8.9 9.3 12.5 2.9 9.9 4.8 8.0 6.3 REGULATORY 21.0 21.8 23.3 25.7 29.0 32.~ 35.8 40.0 41.8 45.3 55.2 64.7 76.4 85.4 93.1 95.6 95.8 96.4 99.8 106.8 112.2 114.2 120.9 125.0 135.8 140.4 BASE FLOOD WATER SURFACE ELEVATION WITHOUT I WITH FlOODWAY flOODWAY (FEn NGVO) 21.0 21.8 23,,3 2~.7 29.0 32 .~ 35.8 ' 40.0 41.8 45.3 55.2 64.7 76.4 85.4 93.1 95.6 95.8 96.4 99.8 106.8 112.2 114,,2 120.9 125.0 13~.8 140.4 21.5 22.2 23.3 2~.7 29.2 33.0 35.8 40.6 42.5 45.3 55.2 64.7 76.6 85.4 93.2 96.0 95.8 96.4 99.9 106.9 112.2 U5.1 120.9 125.7 135.8 140.5 FLOODWAY DATA' ,MAY CREEK INCR£A~ o.~ 0.4 0.0 0.0 0.2 0.5 0.0 0.6 0.7 0.0 0.0 0.0 0.2 0.0 0.1 0.4 0.0 0.0 0.1 0.1 0.0 0.9 0.0 0.7 0.0 0.1 I I I I I il i il I I I I I I I I I I I I King County Surface Water Management [(2 Efe Project ___ _ {17't q{72f'lM P/2.'DP Lff Everyone lives downstream ~'-1---0,-Chk Rev ___ _ Engineering & Environmental Services Date \ "" Date Date Page_ol_Pages -Dl\i.8"'" '> QU~ (...C" "--"-'-I--'leG-\) ( ST /'iN C€ 1 ",.. Ml)oJ~J ... "!. ,." I q~ -Il"'~ :PEJL1/r f'L-MJ ~eL I' '<W;<'</"1" ") 14-G ~ I /<A I Le.S f f g q8/ q<:;o qo~ 14{1J}-, ( f I b4 1M-: 0~7r; C~S-O 7 ':)'1 Z ( I I 61 llJo C;-7 f 0 )7rr C;1Z-100 ._ .•. _ .. _-.-... -- ~v7{( .:::j I / /;ff0 S_'~_.J 11,OLf),( 1""~( 1?~2) -_. __ .- SWM-EngWorkSheeI4122193 01> '" ,-:'f - -& & • TABLE 1 -SUMMARY OF DISCHARGES (Cont'd) Floodina source and Location North Fork Issaquah creek At mouth At mouth (including overtopping from Issaquah Creek) East Fork Issaquah Creek At mouth west Fork Issaquah creek Above Issaquah Creek confluence 2,900 feet upstream of 229th Drive S.E. Above tributary confluence near 208th Avenue S.E. Holder Creek Above confluence with Carey Creek Tibbetts Creek At mouth May Creek At USGS gage 12-119600 At Coal Creek Parkway -.. ~t;. 146th AvenueS.E. At 148th Avenue S.E. At 164t~J\.Y~!:ll!!;L~-,-!:' _._,_ ... _ .... At S.E. Renton-Issaquah Road At S.E. May Valley Road At S.E. 109th Place May Creek Tributary ·Above confluence with May Creek Vasa Creek At mouth At cross section R Drainage Area (sq. miles) 4.B 4.8 9.5 4.9 4.7 1.5 7.5 3.9 12.7 8.9 7.7 6.9 4.8 2.9 : 1.2 0.9 1.5 1. 37 0.53 10-Year 176 176 440 290 270 100 420 220 480 350 310 280 200 130 59 46 72 55 24 Peak Discharges (cfs) 50-Year lOO-year 269 489 725 460 440 160 660 355 315 835 850 550 530 200 800 425 SOO-Year 445 1,995 1,100 790 770 280 1,150' 600 , 800 870 1,020 580 640 750 520 56Q 660 470--""---5To 600 340 370 440 -220---_ ... --2-40-----280- 100 110 130 78 87 100 120 81 38 140 93 44 160 123 60 - - ---- - - --- - ---- - - I I I I I I I I I I I I I I I I I I I 30 330 370 80 2200 3530 25 2090 3100 1320 830 25 905 15 -~ 20 3 !l.1-_~_ . -....... 36 0 730 810 3010 6540 6565 8655 11755 13075 13905 13930 .. _- 14835 14850 15745 15765' v0 J5}65 15405 15035 (j4955 12755 9225 ('9200 7110 4010 2690 -~ <i<ln - ~ ,-.. ~~ v/sU..,f;'( I q b ) f(~STktJ 4T<ff)'/ <:::p-. ::::::=-='-..:::-_____ 50 ~- Ike( % V- . --~? 1lt-- ",-,,--"---' .. -,--. .-14C~ ..",..-...".......,.. ... ~-.,.-' 20 JA JORDAN I AVENT & ASSOCIATES May Creek Study Page 6 assessinq accuracy. Elevationssurv~ed from benchmarks and these spot elevations are usually listed as !.5 foot. The elevations of some remote segments were taken 'from maps of 5 foot contour interval. They are evaluated as !2 feet. Elevations from the USGS map of 25 foot contour interval are assessed as I !5 feet. Elevations taken from the Harstad profile are given as !.4 foot. Bank Slopes: In Segments 912--931, bank slopes were measured on the Harstad cross sections. For most segments, bank slopes were estimated in the field. Natural channels are usually not trapezoidal as required by the S~lf·1M model; and. therefore. precision in these values should not be expected. tlax imum Flow Depth: A'lain the natural changes and irreqularities of stream channels prevented great accuracy in measuring the bank full depths. Values should be considered to be within one foot. '~easurements for culverts represent the actual depth available for·flow as of January, 1977. If the culvert has been filled. this \~i 11 be evident because the nlaximum flow depth wi 11 be I ess than the pi pe diameter. The accuracy of maximum flow depth in pipes is t.l foo.t. f1aximum flow depth may :hanqe during flood cnnditions due to scouring or.filling. Roughness: Roughness was described briefly to aid in selection of a Manning's n. Culverts were noted as . either concrete or CIorrugated steel. and the general conditions of channels were stated. For the mainstream of r~ay Creek. roughness due to mid channel vegetation can be most adequately described by examining the available air photos. G-6 JORDAN I AVENT 8< ASSOCIATES Channel Bottom ~Iidth: May Creek Study Page 5 For Segments 912 -931, bottom width was measured by averaqin,9 four to eight Harstad cross sections within each segment. In a majority of cases, bottom width was measured in the field. Please note that for trfbutaries flowing from the hills, channel dimensions were measured only on the down- stream end. If additional descriptions are needed, these segments can be· further investigated. Normal channel irregularities limited accuracy to within one foot. For Segments 919 -927, the completeness of the Harstad study enabled us to stretch this to within ~ foot. Pipe Diameter: Culvert diameters were nearly all measured in the field to within :.1 foot. Bridges were measured as accurately as possible, from !.05 to ±.5 foot. In the table in Appendix 2, care should be taken to notice that crossinqs may have rectangular, oval or circular cross sections. Segment length: Smaller values (less than 100 feet) were usually determined in the field by pacing. These are !2 feet. lonqer distances were measured and carefully compared on the.base map and on at least one other. map. Values from the most accurate map were chosen. Therefore, base map distances may not be the same .as distances on the table. The table values should be regarded as the most accurate. Table values are at least !20 feet. Inlet and Outlet Elevations: Determination of elevation represented the majority of tiPle expended. Because of the absence or destruction of almost all benchmarks in the basin, most 'surveys were run from points of known elevations. These included spot elevations on road and topographic maps, engineering plat maps and bridge plans. The precision of these starting elevations has been taken into account in G-5 JA JORDAN I AVENT a. ASSOCIATES ,:·:·::J),o\,-. May Creek Studi Page 4 Segment Parameters After the subcatchment was divided into segments, each was described,by seven parameters as required by the SI'IMM I'1Odel: , , 1) Channel bottom width OR pipe diameter 2) Segment length 3) Inlet elevation' 4) Outlet elevation 5) Bank slopes 6) Routjhness 7) ~iaximum flow depth Existing information was reviewed to minimize field work. Major Sources included: 1) 1 ongitudi na 1 This study provided For four of the eiQht miles of ~1ay Creek, a with cross secti ons every 100 feet was surveyed,. information for Segments 912 -931. 2) Topographic maps with 5, 10, and 20 foot contour intervals. These maps were crucial to check surveyed elevations, to supply spot elevations at many points, and to estimate some reMOte inlet and outlet elevations. 3) USGS topographic map of 25 foot contour interval. In spite of the large scale, these maps provided the most accurate positions of stream channels. The upstream elevations of most natural channels in the uplan~s were taken from these maps. 4) Engineerinq plat maDS for urbanized areas. These were used to locate storm sewers. As requested, all storm sewers greater than t"lelve' inches are shown on the base map overlay. As can be clearly seen, most residential areas do not have storm sewers. 5) Road crossing plans for 1-405, State Highway 900, 148th Avenue and 164th Avenue. In addition to describing channel segments, they provided references and checks for our survey. Va 1 ues from the RI BCD study were rot used. A brief discussion about the accuracy, sources, measuring techniques and other pertinent information for each parameter may help in using the data most effectively. G-~ Gl I~~~ I ~t IW-I N \AI SeOl'lent lenQth (ft~ ) 3,030 ('220 1,390 l,OSO 200 30 )'1~n·~ .. ;,r.\'!:'n F,. ~~·snCJ !'T[~ Inlet .1 ev. (ms1) 243:1 186 t 2 147.1t.S 121.3t.5 1107.2t.5 100.2io.5 100.1t.5 100.0t.S .3±.5 20.5tl 20.6t.l 20.5!.1 16.2±.2 lS.5±.2 1 let Elev. (1'151 ) 304.1 t .41 1/1 304.0:.4 Vert. .5/1 243tl .5/1 186t2 1/1 147.1t.5 1/1 121 .3%.5 1/1 107.2t.5 1/1 100.2±.5 1/1 100.1t.5 - 100.0t.S 1/1 89.3!.5 1/1 90.4t.5 Vert. 17.4±.S 1/1 34.0t1 1/1 32.0t1 1/1 21.2t.1 1/1 21.2t.1 1/1 21.S%.S Vert. 20.6!.1 1/2 20.5t.l Vert. 16.2t.2 2/1 lS.5t.2 Vert. 12.910.2 2/.1 "~:Y r:p.r.rK f'r'lt..J',r,r·r >T~!~\ ioht 1/1 Vert. ~CJ X • FlOI·, Depth IRouo~ness (ft. ) 3.5 Mud 110ttom 5.6 r~ud bottom \'r.I~:.I~~\· •. 1 q77 P.oe 14 Rema rks Below inflow of Seqment 345. .,' ... , ',., ," .'IiI' I._ inflow of 1/1 4.0 Thick.inud Vert. 8 Five 1.5 foot Seqrnent 369. -_1IiIIa hnttnml . J< 1 Small bridge. (1% / 1.5/1 12.5 6.8 .5/1 14.5 1/1 4 1/1 3.5 1/1 4.5 1/1 3 1/1 3.5 7.25 1/1 3 1/1 3 Vert. 6 1/2 2.S 1/1 3 1/1 50 1/1 3 1/1 12 Vert. 6 1/2 .5 Vert. 12 2/1 S Vert. 6 2/1 4 supports Gravel bottom Concrete Gravel bottom IGravel bottol'1 I Grave 1 bottom I Concrete I Concrete lira vel Small arch I1ridQe. End Harstad profile; 136th Ave. bridne'does not affect flow. Below Senment 472. Be 1 OI~ Seqment 535. Below Seqment 994. (Honeyde\'/ Creek). Below Se~ment 763. Below Seqment 787. Bridge over NE 31st. Riorapped banks. Below Seqrnent 784. Bridge over NE 31st; elevations double checked. Below inflow of Seament 816. 1-40S freeway bridge as built in 19S6 lake Hashinllton Blvd. USGS Gagin~ Station; V-shaped weir ~/.5 ( :' :JJf. Railroad bridge. r·'an~made cn~nnel; enter lake I'lash. ..... r:: 0: E: ..c: u ..... '" u 0r- '" or. Cl I ~ L. '" or- ~ ..... r:: '" E e '" V> <: 0 Rotton -..... \.Ji d th '" u or -0+-Pioe -..... Di ~. <: QJ (ft. ) '0 CH 4 CU 1.5 CH 5 CU 1.5 CH 3 CU 1.5 CH 2 9201 CHI9.S Serment LenQth (ft. ) 290 30 110 3() 1,800 40 30 1,850 20 2,840 ~3.53Q 2,090 3,100 1,320 \.'I')~n·'\~:lr:.\'[·:T ~ A~~0CIt'.Tr.~ '··\Y CRf.EI: [)~qr;.',r:~ STl'fW lll!';!I!\~V, 1977 ~'~np 1,$ Inlet Outlet Il~nk SloDe r~ax . [lev. [lev. Vert./Horiz. Flo\"' (msl) (T'1s1) Depth (ft. ) Left Downs 451.3:.5 426.0±.5 1/1 1/1 3 426.0:.5 422.4!.5 -1.5 422.4±.5 416.4*.5 2/1 2/1 3 416.4:.5 41S.0±.5 -1.5 415.0t.5 395.2*.5 1/1 1/1 2 395.2±.5 394.8±.5 -1.5 3g4.a±.S 38S.9*.7 1/1 1/1 3 385.9*.7 384.5 t .5 -1.5 384.5±.5 357.1)±.5 1/2 1/2 2 357.0t.5 356 .ot. 5 1/4 1/4 1 356.0:.5 355.9*.5 -3.0 355.9*.5 339.8*.4 3/5 3/5 3 339.8±.4 339.7t.4 -3.0 339.7t.4 327.9 t .4 1/1 1/1 3 Vert. 5 1.5/1 3 1/1 1.5 6.1 1/1 13 L'312. 8t.ti.n1...6! .311. 5/1 11/1 i3. 0 Vert. 4.5 1313. 5±. 3 1309 .8± .4k 5/1 11/1 14 IRourt~ness GrC5sy roadside ditch Concrete Ro~dside ditch Concrete Roadisde ditch Concrete Roadside ditch Concrete Natural channel Brushy Corrugated steel Soi 1 bnk, mud. Bottom sand, gravel, mud Corrugated 1 ~lud bottom, grassy banks IHeavy brush in channel 1309 .8±.4 305.1*'1'1 J:l .u.5 Jravel bottom 30S.1±.4 305.9*.4 .5/1 .5/1 3.5 tlud bottor.1 -_." -- IRe~rks Inflow at Se~ment 003 at upstream end. Two driveways. Bank erosion. Driveway. Rank erosion. Driveway. Bank erosion, small inflow from Sub- catchment 3. Driveway. flank erosion. After inflow of Segment 044. Driveway to camoQround in Subcatch- ment 5. ~ Begin Harstad profile ( .. 1965). Private drive; SE 109th Street. Under iBe10w inflow of Segment 195. inflow of Below inf1ol~ of Segment 319. Below inflow of Segment 333. --- - -- I I I I I I I I I I I I I I I I I I I ~!) t J I) 1979 May Creek Basin Plan's Stream Profile Sta.IO Elv Chnl Lensth Cum Lensth 1 299.8 0 0 (tfGf CP 299.3 ~ 30 304.9 >842 2A 304.2 225 1067 3 304.7 ~ 1747 ILtg:t Q35 303:5·~· 1787 ...... ---~ 3A ;~::~ 2173 .... -!~~~ . -2' ... 3058 . .-~ 4- 4A 306.1 . c.:13@ 6173 5 310.7 )~ 7302 I(,Lf~@ 313.8 -17 9038 '-314 ~ 9078 7 317 .263 11708 8 317.1 4.8/ 13056 8A 319.9 384 13440 9 320.8 (!ill) 14862 Sa.'l"oG9 321.5 ~ 14922 <;r; wr-I C!!f? 328.2 15512 v~ 1«")' 11 328 @ 15870 n' n' '" ... .~ > '" ~ ~, ." -, • I • N.I 'f l , • 'j -I ~ ~ ? I I I I I I I I I I I "!. ~ ~ . , . 1 ~ , jltl-t--r-'.'-,.-"'-.-..... ---t-----+_-.\'If':-:,-~----_-~-,-----.-_-~-------;l--. .--~-. -----..---iii .~ --'-~' -------~;------~---- / -- o", .. i\ ® e ".')@ .... (i> ." , . 30 T~I .~. 1-• I (,I I I I I I I I I I I I I I I I I I I I 17573 322 10 14310.6 <;.eQCO 17602 Bridge Renton-Issaq. Road Bridge CV\lJ.€Nt 17631 322 0.1 14310.7 17641 \E.iIJ 18 14829.7;> ;# q. f 17741 321.5 100 14420.7 18026 326.1 285 14705.7 18216 327.7 190 14895.7 . 18316 327.8 100 14995.7 SE 11\<'1\1· M·18322.5 Bridge 10 is aboul here 18329 ;;)\~~C--:~t"--~:::-? # 10 ..-\ ,; 15095.8 U 1~00.8 /'~·~~·21 l~f~ ~ /::2 """-G7" CJ'-, -.... ~ ~ ~ 1'<\ ~ ,-,", I 'v J ..... ..... ,'-' ~ 0 A::. o· "' ~ .. ~ tV (j\ 1993 Stream Profile HEC-RAS Plan River Sta Min Ch EI (ft) 2756 3061 298.3 302.5 Length Chnl (ft) 10 305 Cum Length Chnl (ft) 10 315 X-sec 1 starts about here + about another 96 ft dis 3571 303.3 510 3591 303.2 20 p.(, -; 3596.5 Bridge -ull I;c<..<.J... . ,_ .•. 3602 303,2 0.1 825 845 845.1 -b\~ ":>~oo I I I I I I 3622 304.4 20 4047 304.3 425 4397 303.2 350 4507 304.3 110 865.1 I 1290.1 ~5 """ A J 1640.1 f~ L11" 6 ~ V"" U 11 .. ,")1&1 6'" Al 4518.5 Bridge 148th Ave Bridge 4530 ~ 0.1 4580 ~ 50 4630 305.3 50 4825 305.3 195 5310.5 Bridge 5316 306.9 5366 306.4 6041 305.8 6646 306.8 6652 Bridge 6658 307.2 6708 306.8 7123 306 7618 . 308.4 7628 308.1 7634 Bridge 0.1 50 695 605 0.1 50 k 455 495 10 ~- 7640 308.1 0.1 7650 308.4 1'0 8835 307.1 1185 9985 310.4 1150 10935 310.1 950 11435 313.3 500 11735 313.5 300" 11835 313.5 100J 1750.2- 1.800.2 1850.2 2045.2 2045.3 2095.3 2790.3 3395.3 3395.4 3445.4 3900.4 4395.4 4405.4 4405.5 4415.5 5600.5 6750.5 7700.5 8200.5 8500.5 8600.5 ~JP."""-~ I 44 ~, ~ 1~'~ ~~~ I I I I I I AS, 11849 Bridge 164th Ave Bridge -"?~-..... ", ..... A'I!iii~~~· "':::J,....,c?~---S"!!816i:~1l\!~l.i~ . .J' # 12323 313.3 410 9060.6 13143 315 820 9880.6 13893 316.4 750 10630.6 14608 316.5 715 11345.6 15488 318.5 880 12225.6 16148 318.7 660 12885.6 16953 319.8 805 13690.6 17563 321.6 610 14300.6 I I I It q .j I rio I I I I I I I I I I I I I I 321.5 326.1 328.5 329.2 10 100 285 14320.7 14420.7 14705.7 15400.8 0.5 0 -4.6 -1.6 -0.7 -0.7 0.05 143.21 0 144.21 -0.46 147.06 -0.16 148.96 -0.01 149.96 -0.07 150.96 -0.07 154.01 --------- Iqq3 c;rrf:#-1 pPaf4 I CAD Values for drawing profile I Min Ch EI Length Chnl Cum Length Chnl Elv Distance (tt) (It) (tt) Elv. Difference Div. By 10 Div. By 100 298.3 10 10 0.10 302.5 305 315 -4.2 ,--:4,.~2j C3.15'_' I 303.3 825 0·.1 0.01 8.45 I Bridge -1.2 -0.12 8.65 304.3 0.1 0.01 12.90 I 303.2. •. 350 1.1 0.11 16.40 I~AV£ Ut.I~C.~ ~ 304.3 110 -1.1 -0.11 17.50 ,14 r ,~~~ Bridge ~ -I /' ---" -0.1 -0.01 18.00 -0.9 -0.09 18.50 I 305.3 2045.2 0 0 20.45 Bridge 396.S 8.1 2946.3 I 306.4 50 2095.3 0.5 0.05 20.95 305.8 695 2790.3 0.6 0.06 27.90 306.8 605 3395.3 -1 -0.1 33.95 I Bridge ( 387.2 9.1 . 33Qa 4 306.8 50 3445.4 0.4 0.04 34.45 .306 455 3900.4 0.8 0.08 39.00 I 308.4 ~ ')0\ 4395.4 -2.4 -0.24 43.95 a98.1 4496.1 0.3 0.03 44.05 Bridge I 398.1 Q.1 44055 308.4 10 4415.5 -0.3 -0.03 44.16 307.1 1185 5600.5 1.3 0.13 56.01 I 310.4 1150 6750.5 -3.3 -0.33 67.51 310.1 950 7700.5 0.3 0.03 77.01 313.3 8200.5 -3.2 -0.32 82.01 313.5 8500.5 -0.2 -0.02 85.01 I 0 0 86.01 Bridge :it~ -( ~ 0 0 86.51 I 0.9 0.09 90.61 -1.7 -0.17 98.81 I 316.4 -1.4 -0.14 106.31 -0.1 -0.01 113.46 318.5 12225.6 -2 -0.2 122.26 I -0.2 -0.02 128.86 319.8 13690.6 -1.1 -0.11 136.91 321.6 14300.6 -1.8 -0.18 143.01 322 10 14310.6 -0.4 -0.04 143.11 I Bridge I I ,I I I I I I I I I I I I I I I I I I Min Ch EI Length Chnl (It) (It) 298.1P 10 302.5 305 303.3. 530 304.3 445 303.2 350 304.3 160 -305.3 245 306.4 50 305.8 695 306.8 655 306 455 308.4 515 307.1 1185 310.4 2100 313.3 900 314.2 50 313.3 410 315 820 316.4 1465 318.5 1540· 319.8 805 321.6 610 322 10 321.5 110 326.1 285 327.7 290 328.5 100 329.2 305 CAD Values for drawing profile Ely Distance Cum Length Chnl Ely. Difference Diy. By 10 Diy. By 100 (It) 0.10 10 -4.2 ,.o.~ 3.05 315 -0.8 ..0.08 5.30 845 -1 .00.1 4.45 1290 1.1 .' "':O:n.> 3.50 1640 '---~ -1.1 ..0.11 1.60 1800f -1 <>.1 2_45 2045 -1 .1 '10.11 0_50 2095 0.6 ,~6lQ1r' 6.95 2790 -1 40.1 6.55 3445 0.8 <-.ll:OS···· 4.55 3900 -2.4 ...0.24 5.15 4415 1.3 '-'::;::':-O:f3'" 11.85 5600 ~----3.3 ~0.33 21.00 7700 -2.9 JlO.29 9.00 8600 -0.9 10.09 0.50 8650 0.9 -:"Ojl9-~ 4.10 9060 -1.7 ,.0.17 8.20 9880 -1.4 ,.0.14 14.65 11345 -2.1 10.21 15.40 12885 -1.3 ~.13 8.05 13690 -1.8 .0.18 6.10 14300 -0.4 10.04 0.10 14310 0.5 _:::::Q,9.5'. 1.10 14420 -4.6 ,.0.46 2.85 14705 -1.6 .. 0.16 2.90 14995 -0.8 10.08 1.00 15095 -0.7 All.07 3.05 15400 May Creek Profiles Comparison 1993 Stream Profile I Cross-sections Surveyed 4/1993 for HEC-2 Model for May Creek Basin Plan River Min Ch EI Length Cum Chnl Station (ft) Chnl (ft) Length (ft) 8835 307.1 1185 5601 9985 310.4 1150 6751 10935 310.1 950 7701 11435 313.3 500 8201 11735 313.5 300 8501 11835 313.5 100 8601 11849 164th Ave Bridge 11863 313.5 0.1 8601 11963 314.2 50 8651 12323 313.3 410 9061 13143 315 820 9881 13893 316.4 750 10631 14608 316.5 715 11346 15488 318.5 880 12226 16148 318.7 660 12886 16953 319.8 805 13691 17563 321.6 610 14301 17573 322 10 14311 17602 Renton-)ssaq. Road Bridge 17631 322 0.1 14311 17641 321.5 10 14321 17741 321.5 100 14421 . 18026 326.1 285 14706 18216 327.7 190 14896 18316 327.8 100 14996 18323 SE MallValley Road Bridge 18329 327.81 StreamProfile_comp.xls tdp 11/20/2001 0.11 14996 1965 Harstad Study Drainage Comprehensive Plan Referenced by 1981 May Creek Basin Plan Techincal Ap~endlx Sta Chnl Chnl Length 10 Elevation (ft) 921 313.5 9200 918 320.3 14955 915 327.8 15735 1979 Stream Profile FEMA Data for May Creek May Creek Basin Plan Technical Flood Profiel for May Creek Appendix, Figure C-1 . Sta Chnl Chnl Length River Chnl Chnl Length 10 Elevation (ft) Station Elevation (ft) 4A 306.1 5900 5 310.7 7030 . I , I I 6 314 '8670 AS 314.5 8290 I 7 317 11340 8 317.1 12680 8A 319.9 13060 9 321.5 14380 BA 322 14045 10 328 15030 BC 328 14784 20f2 ------------______ ,- •. _----------,-_._----May Creek Profiles Comparison 1993 Stream Profile Cross-sections Survol-ed 411993 for HEC-2 Model (or May Creok Basin Plan River Min Ch EI Length Cum Chnl Station (ft) Chnl (ft) Length (ft) 2756 298.3 10 10 3061 302.5 305 315 3571 303.3 510 825 3591 303.2 20 845 3596.5 146th Ave Bridge 3602 303.2 0.1 845 3622 304.4 20 865 4047 304.3 425 1290 4397 303.2 350 1640 4507 304.3 110 1750 4518.5 148th Ave Bridge 4530 304.3 0.1 1750 4580 304.4 50 1800 4630 305.3 50 1850 4825 305.3 195 2045 5310.5 Red Bam Pvt. Bridge 5316 306.9 0.1 2045 5366 306.4 50 2095 6041 305.8 695 2790 6646 306.8 605 3395 6652 Colasurdo East Pvt. Bridge 6658 307.2 0.1 6708 306.8 50 7123 306 455 7618 308.4 495 7628 308.1 10 7634 Private Bridge 7640 308.11 0.1 7650 308.41 10 SlreamProfile_comp.xls Idp 11/20/2001 B1Y8s- 3395 3445 3900 4395 4405 4406 4416 1965 Harstad Study Drainage Comprehensive Plan Referenced by 1981 May Creek Basin Plan Techincal Appendix Seg Chnl Chnl Length # Elevation (ft) 930 300.4 20 929 304 895 928 304.1 930 927 304.1 1835 926 304.5 1860 I 924 305.9 _iQ.!Q L.... ,---- -- 1979 Stream Profile ~~~~~~:~ !~rM~~r:::ek May Creek Basin Plan Technical Appendix, Figure C-1 '-'-- Sta Chnl Chnl Length River Chnl Chnl Length 10 Elevation (ft) Station Elevation Jft) 1 299.3 30 r-'---' -_ .. - '--"-, ._--, I 2 304.9 842 AG 303.1 -, ----~ 850 2A 304.2 1060 ,3 303.5 1755 AI 304.3 1748 304 2055 AI( 306.9 2540 305.4 3425 AM 307 3913 3A 306.8 3690 .. 308 4455 AO 308 4969 1 of 2 I I I I I I I :1 I I I I, I I I I I I I I Doug Chin February 9, 2011 Page 33 Appendix C May Creek Channel Survey Elevations 1965, 1979, 1993,2002 and 2010. May Creek Organic Sediment Sample Results Page 2 Sample Results: • Initial Moisture Content of Material Dried at 140 0 Fahrenheit: 498% (1400 Fahrenheit Oven) • Total Loss on Ignition (Organic Content) of Material Initially Dried at 140 0 Fahrenheit: 15.3% (4400 Fahrenheit Oven) • Total Loss on Ignition (Organic Content) of Material Initially Dried at 140 0 Fahrenheit: 28.2% (1000 0 Fahrenheit Oven) • The moisture content percent is weight of water lost compared to the dry weight of the sediment sample. • The total percent organic material in the sample is 28.2%. • The organic material content percent is weight loss during the test compared to the dry weight ofthe sediment sample. • The 1000 degree test temperature may cause water loss in the clay mineral structure and this would contribute to a high reading for organics. The test was run until the sample weight was consistent. • 28.2% represents an approximate organic content but may be a slightly high result due to test conditions. References King County 2010a. Particle Size Evaluation of May Creek Water Channel Soils, Job Number IB1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, W A. King County 2010b. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, WA. NCRS 1993. Soil Survey Division Staff. Soil Survey Manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://soils. usda. gov /tee hni cal/ manual! Oliver, H. et.a1.2001. Loss on Ignition as a Method For Estimating Organic and Carbonate Content in Sediments: Reproducibility and Comparability of Results, Journal of Paleolimnology 25: 101-110,2001 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ti King County Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov DATE: February 8, 20 II TO: File FROM: Julia Tumey, LG 2493 King County Road Services Division Environm ental Unit RE: May Creek Organic Sediment Sample Results Sample Date: October 8, 20 I O. MEMO Sample Location: The sample was obtained from the May Creek Channel approximately 25 feet upstream from the foot bridge crossing the May Creek Channel (Gam bini and Tse~ay properties 15019 SE May Valley Road Parcel number 0223059091 and 10008 148 Ave SE Parcel 0223059075.) Sample Methodology: The sample was taken using a small three cup plastic container. The sample was scooped from the soft sediment layer on the bottom of the channel. Several passes were made in the sediment to obtain a full container and representative sample. Free water was decanted from the top ofthe container and the soft muck sample was poured into a wide mouth one quart plastic jar with a screw top. The jar was labeled and taken back to the KCRSD office at 20 I S Jackson Street, Seattle W A. The sample was stored in the sample refrigerator in a locked storage room from Oct. 9-11. The sample was transported to the King County Materials Laboratory (KCML) on October 12th. Sample Analysis: The King County Materials Laboratory (KCML) performed testing to determine the percent of organic material. The sample was designated as "May Creek Sediment Muck':' Gambini Prop., 25' Upstream from Bridge". The sample was initially placed in an oven and dried at a temperature of 1400 Fahrenheit to a constant weight to determine moisture content. The dried material was weighed and placed in an oven at 440 0 Fahrenheit until reaching a constant weight to determine the organic material content based upon loss on ignition. Organic matter that had not ignited at a temperature of 4400 Fahrenheit was observed in the sample. The remaining sample was weighed and placed in an oven at 1000 0 until reaching a constant weight to ignite additional organic material. -----~------~------ Particle Size Distribution Report U.S.,SIEVE OPENING IN INCHES U,S. STANDARD SIEVE NUMBERS HYDROMETER 1 'Ii in. 0/., in, 3lBio. #140 6 in 3 in. 2 in. 1 in. y" in. '"'. _ _~ ____ tt:_19_ #20 #30 _~O ____ #5D #100 #200 -~ --~r-Il '" I' ' ; ill ill I i I j I '11111 I I 1001 Jill J Ii':" 'I ITT l' 'tl'U:~1 [':'i' i L i ~--",--L--'-:i;-~Ll'''-l--I--''i'!ll'-'I-11 L1-'i---I' I ' I , ,I '-'" 1--. . " I I I I j I I l' 901-'-1. ~.-" .. 11-.,-t--j--'-1'1' ,---'I-I I Ilil J i I !! i'l iii! I, _ I I I i I I I, I I I, ,. I _, -'-' __ . _ _ 'iT' '-I I I j I I I -1-. -: 7' 1_,--',' '1--i' . I ' ' , I . , 1 I I ,I -' --,-----'11---, ' . I I I 701-'+-I--~---'j+ -r 1 i ,-, 'I '-1 r ~. I ! I I i J __ -.-J L~-rJ I ! I, I --L I -:, +, I __ .1._ .. -, -'1-' -) '-I I I' 'i! ' I ' , '---" '--, r I I' , ! I I ,I '" 60--'-'---I -'''-.•. t I Ii" I I I I ' 1 I I I _1, '_:''';, __ -1"-~ , I I I 1 I L-,-1+1 --H --'I' I' , ~ -LI ___ , j--_1--'_I I'll, --_I---'-J1-1 -rH-,'-il! 1 I I 111'1 : I r I _. z 50 I I I L I I !! I I I I ,Lu_ __ ____ 1 1 __ , ';--'I ,+-__ , __ WI, , ' L _ --. __ • rt f I ' ----, I I, I . . U . I , I. -' ---., __ I. ,"I-, ", I I 'I' ' I I ' IT I . "L --""n' ,-" ~I ' I', ' I I I I , -' __ ,-" -.. H-, -, , , . ' , : .1 ' 301-L. -.. -.. t ,J '. -. -" --III 11 i! ! ,J l_dJ~. _'-. ___ I !~ J ! 1-{ L ! __ I " I I ' , , I I _ ~_t -' L_" -, I' I ' '~~ J ! , I I I I . I I' :. "-1'-,,--,--"[ r, , I I . I" I J'.-----1 ' --.. I' -;' I , I' I " i, , 101----.. I ,1,"; .. -h" --f! I II I \ I I ',I: I I I I ! I : 1 ; I I ; I 'I I, , I I , t ' I ,,' . 001 0.001 " ! iii ! 1 : , I -, 01 _ I , "10 1 o 100 GRAIN SIZE, mm. % +3" I-~'-' ¥'-Coars~ -~t~"l~~ ·-Fin~· -. ___ ' __ coa~s;·t=-=-MediU: ~~-~\-----Fi~~~' ~ sat Clay % Fines --_. ~ . _." . 0.0 0.0 0.5 l.l 14.5 50.S 33.4 Ii ---_ .... _--- I I J Client King County KING COUNTY ,0 148th, 7S' downstream from bridge, N third ofchaIlllel . \ Project May Creek Stream Bottom Evaluation ,lfrQject No. 1B120S Figure 3 I MATERIALS LABORATORYI J .. ........:. • .... _... "-,,,t ••. -----------------------~----~------ II Particle Size Distribution Report Ii a: w z u:: f- Z W U a: w 0.. 0 0 U,S, SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS Hl'OROMETER S'in. 1 Y: In. ',.~ irt 3/8 in, #140 3; ."m: 210. • 1 in. ~~~ #10 #20 :7ao :~O .':60 #100 i..'200 --h---:' ;~'_X I 7JlJL1l2 l~~! I ! '! 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I :! 1 1'-. , j , 401 I -.----. -]1 i-..L --.' __ .l ·t .. ---H .' I -T--I'IJL J I .. : -·1·]1. -~ ~-~ .. ~---~t"- I I! I' i t I I i I! ! I I I I" '] I : II I T"=;J, ',,', d'i ' '1 1,1!11 I, I I' :, "! II!\I: ,'0 ' li!i;' j. ' j ~ '" 30 I·' I I -, " I -, I ---I ! ! I ., . -, • I -'1 ., --"1-J :, ----' . --'i·' I . Ii 'i' i '! I I I ' ! 'I I' i ' ' Ll I 1 , I , , ! II I-I! I' ., t 1 i I It,!! j .j !I It! I I \. l!! I 1, I' , , , 1 , , , I 1! \ -;--..." ' , 201 ,-,. I j '. ,J . __ ,1,;..1._' I ---II f' ., : • . .,. -,-' , ---, .-, 't I I 'II!' I : I i I I I . i! II ' I I I ~'+-..-! I' "I , ! I ! J'i I II! i I I I I " I I ~T-=~-i-tJN'-.t 101--1' ... ---I-H ['. -, .II! :-.'-. III' -I -, I -" !, '.7.;::1-1-"); I! III I I! ! , ' I I !, I ! ! I ! ' , , I , I I l', ' , 1 ,I I j I' . ~ 1 > l ! 01 j i !! III ' i: i I ! , l . i I I I, I, I i I I i I I -I I --,- I ! 10 '0.1--0.01 100 13.4 I Coarse I 0.0 % Gravel --~e Fine 2_0 2.4 % Fines % +3" 0.0 Fine Silt _ 33.6 38.1 Clay '0.0 I 0.0 0.5 I 4.2 45.9 27.9 I II --, 'I I ! I II 'I r 0.001 I Ii ! 'f:, 0.0 7.7 0.8 I 0.5 19.5 46.9 . ····-18.0 Ii U Source 01 ~ ~ Glient King.c'::ounty Project May. Creek Stream Bottom Evaluation Proiect No. lB 1205 Figure 2 MATERIALS LABORATORY Tested By: vw.~~~~~ ____ _ ----------~---~---- Particle Size Distribution Report U,S. SIEVE OPENING IN INCHES U.S. ST At,mARO SIEVE NUMBERS HYDROlvlETER 1}i in. v.. in. 318 in. #;140 6 in. ".l-.\q, " 2irt , in. ~ in. #4 '110 #20 #30 #40 #iiO #100 #2OD -,""-jT· --ii I I IP 111 11-: i '1111111 ,.1111 III i 901-, ---TI' I \fl rJ IJIJ---I-I" ,-r-Il I i l ' I i r!!~ I _, 1-+, --I-!-I r 1001 lJ f.' I~I~ 1\ r L I~_I ru-~[~.---1'-1-Ii !. i -,-t.fl -iTI+~-( IJ __ L --H-+~1 1+1 '1-- --11 -. -!_.-I 'I, '. ___ , +--1--I I I , "H--h--, ~. .' " -'. 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Iii I. ,) .. 1 I !, I I , fO GRAIN SIZE _ mm. o ' I 100 %+3" 11.4 0.0 0.0 % Gravel Coarse-~I-·-Fine 33.0 43.6 50.6 31.3 57.0 28.7 % Sand -,-.----r ·------1 Coarse I Medium 5.2 4,6 6.7 T-6.7 I 6.3 I 6.7 __ !o_Fi~~~ __ ~_ Fine Silt Clay 1.9 0.3 4.2 0.5 1.0 0.3 Source Sample # I DepthlElev. Date Sampled L uses MateriaiDesC!iptionl NM % I LL I PL KC-10-426 4/27110 GW Well-graded gravel . I NY I NP 0 b KC-IO-427I KC-IO-428 'I I "-VjV"'~' 4/27/10 GW Well-,aded gravel with sand ! . '--, NY NP ,,~ .n .on 4/27/10 GW Well-"",ded gravel I I NY NP . Client King County . Project May Creek Stream Bottom Evaluation Project No. 1B1205 ,Figure Tested By: ..lv'!wL-________ _ KING COUNTY MATERIALS LABORATORY Ci" McFarland residence, upstream from bridge o l46th Ave SE, upstream side of bridge "-l46th Ave SE, downstream side of bridge Particle Size Evaluation of May Creek Water Channel Soils Job Number 181205, Task MTR Page 4 of4 5/11/2010 determined as previously described for Area 4: 146th Avenue SE, Sample KC-10- 428. Most all materials larger than about 3 inches had sharp edges and a few pieces of broken brick were encountered. Material size counts for the upstream and downstream sides of the bridge are shown below as Table 2 and Table 3, respectively. TABLE 2 Sieve Size Count Sieve Size Count -1 1/2" Fines 2 8" 2 2" 2 9" 0 3" 3 10" 0 4" 6 10" -12" 0 5" 5 12" -15" 2 6" 3 15" -18" 0 7" 1 TABLE 3 Sieve Size Count Sieve Size Count -1 1/2" Fines 1 8" 3 2" 0 9" 0 3" 1 10" 0 4" 2 10""': 12" , 1 5" 4 12" -15" 1 6" 8 15" -18" 2 7" 4 We appreciate the opportunity to have been of service and trust this report addresses your current needs. Please call me at 206-391-0552 or Alan Corwin at 206-296-7711, should you have questions or we can be of further assistance. Attachments: Figure 1 -Laboratory Test Results KC-10-426 through KC-10-428 Figure 2 -Laboratory Test Results KC-10-429 through KC-10-431 Figure 3 -Laboratory Test Results KC-10-432 Report of May Creek Sampling & Testing I I I I I I ·1 '. I I I I I I ,I I I I I - -------------------- I I I I I I I I I I I I I I I I I I I Particle Size Evaluation of May Creek Water Channel Soils Job Number 181205, Task MTR Page 3 of 4 5/11/2010 Sample KC-10-428: The sample was obtained using hip waders and a shovel from the thalweg area of the creek channel, immediately adjacent to the downstream side of the bridge. The water was approximately 2 feet deep, flowing moderately fast and the surface of the water channel consisted of sands and gravels. Some of the fine sands were washed off the shovel while sampling due to the moderately fast water flows. It is roughly estimated that 60% percent of the bottom of the water channel surface area consists of sand and small gravel. A gradation test using conventional screening methods was performed on material finer than a 3" sieve and the USCS classification for this material is well graded gravel (GW). larger gravel, cobbles and occasional boulders with a maximum particle size of about 12 inches make up the remaining approximate 40% of the channel bottom surface area. The sides of the channel directly adjacent to the abutment are armored with broken pieces of concrete. A few pieces of broken concrete were observed in the thalweg of the creek channel. Directly downstream from the concrete armoring the sides of the water channel are undercut. An estimate of the overall creek bottom material gradation was obtained in the vicinity of the thalweg. The evaluation of material gradation was determined by reaching into the water and randomly touching a location on the creek bed. Material encountered at the bottom of the creek bed larger than 1 inch was removed from the water and measured. Materials finer than 1 inch were visually assessed as being similar to materials from sample KC-10-428 that were also finer than 1 inch. The particular sizes of material found on the creek bed were recorded and are shown in Table 1. The dimensions shown in Table 1 are approximately equal to a square mesh sieve that the materials would pass. TABLE 1 Sieve Size ·Count Sieve Size Count -1" Fines 5 5" 2 1W 5 6" 1 2" 5 7" 1 3" 5 12" 1 4" 0 • Indicates number of times the referenced size of material was encountered. Area 5: 143rd Avenue SE Samples of fine materials for laboratory gradation testing were not obtained from the bottom of the creek channel. The water was approximately 18 inches deep and flowing fast. There was very little fine (sand size and smaller) material present on the creek bed surface and representative samples could not be obtained with a shovel or similar tool due to the fast flowing water. An estimate of the overall creek bottom material gradation was obtained in the vicinity of the thalweg. The estimate was performed directly adjacent to, and on the upstream and downstream sides of the bridge. The evaluation of material sizes was Report of May Creek Sampling & Testing ----------------- Particle Size Evaluation of May Creek Water Channel Soils < Job Number 1B1205, Task MTR ,=-----;--,--,'=:-;-;::---" :Gambini 2010 . Area 2: McFarl~d Property (Yellow House and Out Buildings) Page 2 of 4 5/11/2010 Sample KC-10-426: The sample was obtained at the confluence of a small unnamed stream and May Creek, approximately 30 feet upstream from the bridge. The water depth was approximately 12 inches with moderate flow and the surface of the water channel consisted of dean sand and gravels. This sample represents materials from approximately 0" to 6" below the bottom of the channel. No significant vegetation was noted at the sampling location. A gradation test using conventional screening methods was performed and the USCS classification for this material is well graded gravel (GW). Sample KC-10-431: The sample was obtained using chest waders and a shovel from the south side of the water channel, approximately 100 foot upstream from the bridge. The water depth was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately 0" to 6" below the bottom of the channel. At the sample location, the bottom of the channel did not appear to be covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is sandy silt (ML). Area 3: 14Sth Avenue SE Sample KC-10-432: The sample was obtained using chest waders and a shovel from the north side of the water channel approximately 75 feet downstream from the bridge. The water was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately 0" to 6" below the bottom of the channel. At the sample location, the bottom of the channel appeared to be exposed and was not covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is silty sand (SM). Area 4: 146th Avenue SE Sample KC-10-427: The sample was obtained using hip waders and a shovel from the thalweg area of the creek channel, immediately adjacent to the upstream side of the bridge. The water was approximately 2 feet deep, flowing moderately fast and the surface of the water channel consisted of sands and gravels. Some of the fine sands were washed off the shovel while sampling due to the moderately fast water flows. It is roughly estimated that 75% percent of the bottom of the water channel surface area consists of sand and small gravel. Larger gravel and cobbles with a maximum particle size of about 4 inches make up the remaining approximate 25% of the channel bottom surface area. A gradation test using conventional screening methods was performed and the USCS classification for this material is well graded gravel with sand (GW). The mid-stream bridge pier appears to have 12" to 18" rip rap placed as armoring on the upstream nose of the footing/pile cap. Report of May Creek Sampling & Testing I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ti KlntCowIty Road Services Division Materials Laboratory Department of Transportation RSD-TR-0100 155 Monroe Avenue Northeast, Building 0 Renton, WA 98056-4199 www.metrokc.gov/roads May 11,201.0 TO: VIA: FM: RE: Jeff Burkey, Hydrologist, King County Department of Natural Resources and Parks, Water and Land Resources Division Ala~ Materials Engineer, King County Department of Transport tion, Road Services Division, Materials Laboratory =---""",-.",.- Hyden, Engineer III, King County Department of Transportation, Ices Division, Materials Laboratory The King County Materials Laboratory (KCML) obtained soil samples and performed field evaluations to determine the distribution of soil and rock particle sizes in the water channel along a section of May Creek. Areas from which samples were obtained or evaluations performed are summarized as follows: Area 1: Colasurdo Property (Red Barn) Sample KC-10-429: The sample was obtained using chest waders and a shovel from the north side of the water channel approximately 75 feet downstream from the bridge. The water was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately 0" to 3" below the bottom of the channel. At the sample location, the bottom of the channel appeared to be exposed and was not covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is sandy silt (ML). Sample KC-10-430: The sample was obtained from the same location and using the same methods as KC-10-429, except at a depth of approximately 3" to 6" below the bottom of the channel. At approximately 3" there was a transition in the soil and it was visually classified as a mixture of the silt from KC-10-429 with gray, fine silty sand. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is silty sand (SM). Report of May Creek Sampling & Tesllng , I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 23 Appendix B Channel Bottom Sediment Sample Analysis ~. --.~-- --• " .. I • ... ~.,.,; • i-:~ " 1t""fi~:\ :. r ~ ':"l~i " ~,f .. TI" I ------f; ---- I "~ . . .. . , " -··t-- i ! ...... {~ ·rr 00 ........,]:; I N'I I!n '.~ Ii .. , ,(1) I~~ r:;' . .,- I I" I" , \ J I I I I I I I I I I I I I I I I I I I May Creek Drainage Project, May Valley 1936 Aerial Photo 79,1aI5OOl 79,000I58,00Q37,OOO16 ,OOO F .. l -- --- - N + U1 King County I Doug C hin February 9, 20 11 I Page 20 I I May Creek Drainage Project, May Valley Lldlr Imlge 2002 I I N + I I I I I I I I I I I Foot tG King County I I .. "" ~ -'" -_.. , .... I I I I I I I I I I I I I I I I I I I Doug Chin January 10, 20 II Page 19 Appendix A Aerial Photos and Historic Maps Doug Chin February 9, 2011 Page 18 Environmental Consultants, Inc. http://green.kingcounty.gov/WLR/Waterres/StreamsData/reports/grecn- duwamish-Ioading-report.aspx King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. 2010b. King County GIS Center LIDAR, Topography, Geology, and Stream Location Layers, viewed with ARCGlS http://www5.kingcounty.gov/gisdataportall King County. 2010c. Particle Size Evaluation of May Creek Water Channel Soils, Job Number IB1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, W A. King County. 2010d. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department ofTransportat~on, Materials Lab, Renton, W A. King County. 2010e. May Creek Drainage Improvement Project 70% Design Progress Plans dated 10-22-10. King County. 2010f. Baseline Stream Conditions May Creek Drainage Improvements, CIP#9AI205. NCRS 1993. Soil Survey Division Staff. Soil survey manual. Soil Conservation Service. u.s. Department of Agriculture Handbook 18. http://soils.usda.gov/technical/manual/ Yount, J.C. and Glower, H.D., 1991 Bedrock Geologic Map of the Seattle 30' by 60' Quadrangle, Washington: U.S. Geological Survey, Open-File Report OF-91-147, scale I: I 000000. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 20 II Page 17 References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. Booth, 0.8., Haugerud, R.A., and Sacket, 1. Geologic map of King County, Washington: scale I: I 00,000. Bretz, J. Harlen, 1913, Glaciation ofPuget Sound Region, Bulletin 8, Washington Geological Survey, 244p. Burton, G. Allen, and Robert Pitt. 2002. Storm water Effects f:landbook: A Toolbox for Watershed Managers, Scientists, and Engineers. Lewis Publishers, Boca Raton, Florida. http://www.epa.gov/ednnrmrl/publications/books/handbook/toc.pdf Foster Wheeler,. 1995. See King County, 1995 below. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. Hart Crowser, 2009, Final Site Investigation Report, Loon Lake, Washington, prepared for the Washington Department of Natural Resources, 117 p. Access online September 20 I 0 at: http://www.dnr.wa.gov/Publications/agr loon lake final invest report. pdf Homer, Richard R., Joseph J. Skupien, Eric H. Livingston, and H. Earl Shaver. 1994. Fundamentals of Urban Runoff Management: Technical and Institutional Issues. Prepared by the Terrene Institute, Washington, DC, in cooperation with the U.S .. Environmental Protection Agency. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. April 2001, May Creek Basin Action Plan. King County Department of Natural Resources, Water and Land Resources Division. King County 2007. Water Quality Statistical and Pollutant Loadings Analysis -Green- Duwamish Watershed Water Quality Assessment. Prepared by Herrera Doug Chin February 9, 2011 Page 16 canarygrass will slow narrowing of the channel. Active monitoring and buffer-planting management along the creek banks will take place for ten years to allow establishment of native vegetation buffers. The larger channel can be expected to last beyond ten years. This assessment is based on qualitative analysis with available information. Quantitative sediment estimates are not available. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 15 • Reduction Reduce channel narrowing by controlling reed canarygrass along the banks by establishing a buffer of plants on either side of the channel and shading the banks. • Temporary Increase Channel excavation will temporarily expose "raw" bank and channel sediments to the channel. Jute matting and bank planting will control erosion but minor erosion within the channel may occur as the channel stabilizes. • Change in fine sediment movement Fine mineral and organic sediments that reach May Creek and are now stored in the stream channel or trapped by grass during low flows will move downstream during lower flows. Fine sediment and organic material currently stored in the channel and moved downstream during high-flow events, will move downstream at a constant rate rather than episodic rate. The overall estimate is a net reduction in fine sediment and organic material reac~ing May Creek within the project area. Long Marsh Creek mitigation, the mitigation alcoves, reduced flooding, and reed canarygrass control are project features that decrease sediment contributions to May Creek in the project area. Controlling willow and reed canarygrass will control channel narrowing. Responses to Questions on Project Performance Question 1: Will the project change sediment delivery downstream to May Creek? Response: The May Creek Current and Future Conditions report (Foster Wheeler, 1995) identified the major sources of sediment to May Creek as coming from the ravine and tributaries below May Valley. The hydraulic analysis (King County, 20l0a) shows that changes in flow velocity below l43rd Avenue SE are negligible. Sediment movement is controlled by flow. Therefore, the same size sediments would be moved within the May Creek system. Muck sediments are currently stored behind topographic highs in the stream channel and are moved downstream in pulses during high flow events. In general fine sediment that does enter the creek as bedload or suspended sediment will move downstream due to improved channel efficiency rather than being stored in the creek channel above 148th, incorporated into the banks and moving though during large flow events. However, some fine sediment or muck that does enter the creek will continue to be stored behind topographic highs in the channel or in topographic lows above and below 148th Avenue. We estimate the project-related reductions in sediment delivered to the creek primarily from reduced overbank flooding, will reduce the total fine sediment and organic muck in the stream. Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? Response: We estimate that there will be an overall reduction in sediment contributions to May Creek within the project area. The stream channel bottom elevation is relatively stable, except where Long Marsh Creek discharges to May Creek and where reed cannarygrass and muck aggrades the channel. Reducing sediment and organic matter input to the channel from Long Marsh Creek and the pastures and removing reed Doug Chin February 9, 20 II Page 14 • • • • • • • Adding plant buffers on either side of May Creek will shade the banks where reed canarygrass is present and help control grass growth and encroachment. Reducing over-bank flooding of pastures will reduce the amount of sediment and organic material being carried to the creek by an estimated .2 to 0.8 metric tons per year. Improved channel hydraulic efficiency will improve and move fine sediment and organic material that reaches the creek downstream, reducing the amount of sediment trapped in reed canarygrass above I 48th Avenue SE. The proposed alcove excavation and planting areas west of 148 th A venue SE will allow the creek to overflow into the alcoves during higher flows; this will slow the current velocities and minor amounts of sediment will drop out of suspension, but the amount of deposition is unknown. The May Creek channel is likely to be both a depositional area and a source of suspended sediment during higher flows. Soft muck in the stream bottom above the confluence with Long Marsh Creek is a combination of organic material from pasture runoff with mineral sediment. The muck builds up in the channel after rain storms and floods and is moved downstream during higher flows. Reducing flooding within the project area will help reduce the build up of muck in the channel. A mitigation project in Long Marsh Creek will intercept gravel and large sand-size sediment reaching May Creek. Bank stabilization with jute netting and seeding will reduce erosion and sediment input to May Creek after excavation. Estimated Changes in Sediment Transport and Channel Dimensions after Drainage Improvement Project: The proposed project elements and existing conditions were evaluated for how sediment would ente~ and move within the project area. If no change in behavior was expected, the conditions were assumed to remain the same and are listed below as "constant". If the project element was expected to modify sediment behavior by qualitatively reducing the amount of sediment reaching May Creek, a reduction is noted in the bulleted list below. During construction, temporary increases in sediment are possible and this is noted. • Constant Upstream May Creek (east of 164th). Most of the major tributaries enter May Creek above the project and therefore will continue to be a contributor to fine sediment in the Creek. Beaver dams will hold back sediment and periodically release it when breached. • Constant Tributaries (0291A, 0291 and Indian Meadows Creek) contribute unknown amounts of fine sediment. These are expected to be minor. • Reduction Small proposed mitigation alcoves downstream from 148 th will allow sediment to deposit at higher flows. • Reduction Long Marsh Creek mitigation project will minimize course sediment reaching May Creek and channel infilling. • Reduction Reduced pasture flooding will reduce the organic material and sediment discharged to the stream, estimated at .2 to .8 metric tons. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 13 Findings: Project Features and Estimated Results Pre-project May Creek Sediment Sources and Channel Behavior above the May Creek Ravine: Based on field reviews of the project area, stream report (King County, 2010), a literature review of past reports on the May Creek basin, and a review of aerial photographs a qualitative estimate of sediment sources has been developed. Sediment entering the project area comes from: • Upstream May Creek (east of I 64 th ). Most of the major tributaries enter May Creek above the project and therefore will be a contributor to suspended sediment in the Creek. Six beaver dams are present or have been active in the past above the project area; two below I 64th and four upstream of the project. • Long Marsh Creek is a contributor to channel fill by sand, gravel and small cobbles. The larger materials are able to reach May Creek during high flows due to the straight channel, slope and past channel maintenance by property owners. • Indian Meadows Creek is a minor drainage that is partially ditched through a pasture that reaches May Creek and contributes sediment to May Creek. • Tributaries (0291 A, 0291) contribute minor but unknown amounts of fine sediment. • Stonnwater runoff and pasture flooding contributes an estimated .2 to .8 metric tons of organic material and sediment to the stream. The May Creek channel is essentially a ditch, excavated in a historic wetland system prior to 1930. The gradient in May Valley is very low and the creek is only able to transport clay to sand sized sediment. • The May Creek channel stores organic muck/sediment from pasture~ behind relatively high spots in the channel bottom and releases it downstream to the ravine during higher flows. Muck then builds up again as flows recede and during rain events. Some of the muck contributes to aggrading the channel bottom as it is trapped and entrained by vegetation. The May Creek project proposes a number of features to reduce sedimentation to May Creek and channel filling. The 70% design plans include: • removal and control of reed canarygrass (Phalaris arundinacea); • native plant buffers along the banks; • reducing overbank flooding; • selected removal of vegetation from the channel downstream of 148 th Avenue SE; • excavated alcoves adjacent to the channel downstream of I 48th Avenue SE, • a sediment management design for Long Marsh Creek, the primary source of sediment and channel constriction in the project area. These features are expected to produce the following results: • Removal and control of reed canarygrass will slow channel narrowing and infilling due to growth during spring and summer during low flows. I I I I I I I I I' I I I I 335 I 330 I 325 ~--------~--~----~--:---:---:---~--:---__ --------__________ ~'335 330 325 I 320 III 315 310 320 . ;JI' .. ; . ~P~~~i<.~~~~O~tJNE~· L' . : ... ~~~NE~' L" .. : ... 2~b2' .: ... < _. . ..... CHANNEL. .. '-'-'C·· ~--' ..... '-'0' '-'-' :.;.c ... :~_.~._. : 'O-_~--'--' :-=-=----.~. . . ·1310 315 Ii::: 295 305 300 295 I I 290 OTVV L----'---'----'~---'-----'----'-~~o_---'-------'~~~--"----'---~~c_~---'290 9+00 10+00 11+00 I I ••• II 40 0 40 80 120 SCALE IN fEET III DETAIL 1 SCALE: 1";40' I MAY CREEK CHANNEL RESTORATION FIG.~ PROFILES [jIJ.. II 80_ _ _---.!L 80 160 240 SCALE IN FEET 3351 . ,335 330 325 320 315 310 305 300 295 .... . . -"'-..,----.-••• -. oa:!i -, 16+00 APPROX. ELEVATION. : .. ~201O . _ OF MU: ATFLOWUNE •• 1 __ CHAr L . • . 17+00 18+00 19+00 330 325 320 315 310 -;----._-7""'- 305 300 295 20+00 21+00 22+00 23+00 SCALE IN f'EET DETAIL 2 SCALE: ,·",40' I I I I I I I I I I I I I I I I I I I 320. .320 ';-2010 : CHANNEL :2002 :CHANNEL 3101 ...-.C---.--\\Jf -- 3001 -100 Jo 6 56 SECTION A-A STA. 7+00 DOWNSTREAM OF 148TH ST NlS ·'310 J300 1 0 CD '--"" 320. ~nn., .320 310'· - :2010 :CHANNEL ,- ..) .. /. .. "310 3001 b b I /300 -100 -0 50' SECTION B-B STA. 8+00 UPSTREAM OF 148TH ST NTS f2\ '-/ MAY CREEK CHANNEL RESTORATION FIG. ~ CROSS SECTIONS 3201 .320 310 1. 3001 -100 -~o 2010 CHANNEL 6 ,~ SECTION C-C STA. 15+00 2002 CHANNEk- ~ 56 DOWNSTREAM OF LONG MARSH CREEK NTS "310 J300 1 0 ffi '--"" 320~------------~=:~~,---------~~~,-----c:=::= 2010 1 ;:--2002 1 320 CHANNeL j: CHANNEL {------: 310"" "310 , . 3c:~100 -Eo b 56 1 AilOO SECTION 0-0 STA. 16+00 LONG MARSH CREEK NlS L4\ '--"" 3201 .320 310" 3001 -100 NOTE, -=--=------ ~O c\ do SECTION E-E STA. 17+00 2002 CHANNEL UPSTREAM OF LONG MARSH CREEK NTS ALL CROSS SECTIONS ARE CREATED LEFT TO RIGHT LOOKING UPSTREAM . ·'310 J300 1 0 f5\ '--"" " I I I I I I I I I I • I I I I I I I I Doug Chin February 9, 2011 Page 10 Channel Bottom Elevation Channel elevation surveys were conducted in 1965, 1979, 1993, 2002 and 2010 (Data is located in Appendix C). A profile of May Creek channel from just below 148 th Avenue . SE to approximately 1,300 feet upstream of the confluence with Long Marsh Creek as shown in Figure 5. The figure compares the 2002 and 2010 survey profiles and gives spot elevations at the 148 th Avenue road bridge and at the horse-crossing bridge on parcel 0223059091,15019 SE May Valley Road from 1965, 1979, and 1993. Upstream of Long Marsh, between 2002 and 20 I 0 the hard channel bottom is a foot lower in some areas and a foot to two feet higher in others. At the horse bridge the elevation has varied from 307 feet to 311 feet associated with sediment deposition from Long Marsh Creek. From station 11+00 to 8+00 at 148 th Avenue, the channel profile has flattened and the channel bottom has shallowed approximately three feet. This area coincides with thick areas of reed canarygrass. Between 1965 and 2010, the 1 48 th Avenue road bridge channel profile has stayed relatively consistent at 307 to 308 feet. It appears from the elevation differences that where the muck and vegetation builds up, the channel bottom has also been aggrading. Changes in the bottom elevation should be considered approximate, perhaps within a foot of elevation change. Survey elevations have not been taken at the exact same locations and stationing is different between projects. Stream profiles in 2002 and 20 I 0 (Figures 4 and 5) show thicker areas of muck build up behind higher elevations in the channel. Up to four feet of muck was measured above the Long Marsh Creek confluence in 2002 and three feet in 20 I O. Stream and elevation survey data indicates that soft muck present in the channel varies in thickness by location and with time. The muck thickness is variable and transitory, building up in the channel until higher flows in May Creek are able to move the sediment downstream. , Muck and fine sediment is moved downstream by May Creek within the valley as bedload and suspended sediment. However, the valley and May Creek above May Valley is not the main source of sediment to Lake Washington. The May Creek Current and Future Conditions report (1995) identified the major source of sediment to the May Creek delta in Lake Washington as the May Creek canyon and eroding channels of tributaries that enter the mainstem downstream of May Valley. Elevalicn (ft) w w w w w N8 0 -" ..... '" ~ (/I 0 VI 0 o~058"-4.18 I I o I ".100, , ..... " \ . .........1. ,: " \ , . "'1-"::'\ 4.265343 DO'Mlstream of Rock Weir " ~ 4.278770 DO'M1stream of 146th Brid.. ' " --:---... -1 ---.=- 4.310823 KC Survey year 2)10 __ _ ,-~ it 4.323418-t 1 '. r, f .: • -?f-----. ~ 1.4.353836 KC Survey year 2)10-=-= ' ... 1~'--' --'-'--~-:--------;I----:-----7--:---I g 14.369391 KC Survey year 2)19 .J 1 4.387575 KC SUlVey year 2)10 ' "\ " 4.41~OO3. : . : 1 _ ~ 4.426539 KC Survey year 2.)10 l -\_ '< " il ~ m ". m a. , :::~~ctIet3~~i-; --1 ~-'.~-;-~-- 4.472884 KC Survey year 2)10 (similar to OTA .. '" (") o , 0-4.482002 KC 5UfVey year 2)10 ~ "'-H: :::-~ -'---~ -i--~· 't g 14551598 -t i *-~-~\,~~~,--,-----+---,---~----'--~----j g-, Z ~ '" '" 4,575359 KC Survey year Zl10 ~, 1 ~ , Q) 4,600738 "t -~ ·--t i -.: . ~_=--"1J :i' 4.622613 I -r 3: -g 4.640315 / ~ ~ ~ --I" / g , ,~ !!. ,J_ ,/-/.l 3:;,;;; ~ 4.700732 KC Survey year alia (similar to OTAK X.. 1/ / ~. (") • N . I ~ "-~ I ~ g, .' ,i .,-'I-CD ~ : 0 4.749514 KC Survey year 3)10 (similar to OTAK XS.. 11, 3 z -= -' --' -'. -' -I -. \' 1·1-I I I I, "I -" 4.788456 KC SUfVey year 2)10 (similar 10 olak X5 . \\ "~"I~'f ',~ ~ 4.887389 .... ....: -!. "::......: ':-_~ : .. ::::~:.,C _~u~~.:~r2)101 ("":a,,o ola', I; ~ ~ , , '" Ii :::;~::c s~~~~~r 2J_1r~i=i~~rto :Iak :~.. ~ 4.949111 KC SUfVey year 2J10 (similar 10 otak X5 ... en 4.9""24.:: --~~--.-r --'';'~ ~ :;. ? '-, ~ 4.900154.L _.1 _ , __ 1 -' ~ ." _ 1-.../ r I -r--" , ~ 1 , "I W , 'l . '. l I, j\J 5.038968 olak xs 7515 '1"-' 0) .5.04 fodtric:ge up;tream of Calasurdo property --r N , - o . '-t If-) \ 0 I~ \1 f' t e Z 1~~~?!5?3 o~~k_~ ,7ffl5: t---'-r'-.......1..::...,' o o 5.1:B954 o~ak X5 8005: ~ "-"'""'1'" , -, I , ~ I I ;5.1~707 o!ak xs .8315_~_ , -r -:+ -T' ..:1-":"':::"1':' ~I"I rl~ll:; -OIOg,cg OJ OJ1OJlcn :::J ~ I I ~ CL '(eOIOl'AjUno::> gUDI WOld) OlOl til SS'U~Jlq.L jU'Wlp'S~Jnw pue UO!jeA'13 WOnOS I,uueq::> ilu!NloqS 'I!JOld ~OJl::> AeW £ ,milld 6,jled o IOl '8 "'qW'J'a U!q::> ilnoa Doug Chin February 9, 2011 Page 8 May Creek Channel Changes with Time Horizontal Boundaries Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited vegetation. Foster Wheeler measured the mean May Valley Creek channel width in 1995 as 20 to 25 feet, with wider sections up to 60 feet at RM 5.6 (Foster Wheeler, 1995). In March of2002 a stream survey was conducted between 164th Avenue SE and 148th Avenue SE (O'Rollins, 2002) and measured the average channel width at ten to 14 feet. A stream survey was conducted in 2010 (Thompson and Bauman), and the average wetted width of habitat units was approximately 12.1 feet and the widest wetted width was 23 feet (surveyed reach RM 4.35 to RM 4.87). While no change in average width occurred from 2002 to 2010, there is a possible pattern of channel narrowing between the 1936 and 1995 and comparison between the 2002 and 20 I 0 stream surveys. This is reflected in the available measurements; especially in areas dominated by reed canarygrass. The channel is still a relatively straight excavated ditch but grass, shrubs and trees have encroached into the channel. Survey data from 2002 and 2010 surveys are also available. Cross sections of May Creek are shown in Figure 4 (cross section locations are shown in Figure 5). Five cross sections were chosen to compare the stream channel at relatively fixed locations in the stream. Upstream of the road bridge at 148th Avenue SE the channel is narrower and slightly shallower (Section B-B). Downstream of the bridge the channel is wider and more uniform in shape (Section A-A). The cross section at Long Marsh (Section 0-0) shows the 2002 bank deposits (right bank) associated with excavating sediment from May Creek (private property owner activity) and the filled-in 2002 channel profile from Long Marsh Creek deposits. During the 2002 pilot excavation project in May Creek at the Long Marsh confluence, sediment was removed to approximately elevation 309. The left bank (looking upstream) has now filled in to 2002 elevations at the confluence but the rectangular channel shape is still present on the right bank. Upstream of Long Marsh Creek, the channel is approximately the same width but shallower. This may be due to where the survey staff was placed and the CAD program interpolating between points. Downstream of Long Marsh Creek the channel has narrowed. Survey locations varied slightly between center line, right bank or left bank and cross section elevations are approximate. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 7 communication). Finer sand and silt reached May Creek and the confluence with May Creek is clogged with silt and reed canarygrass (GeoEngineers, 2008). • Tributary 0291a is shown on the 1872 map and before development of the valley flowing northwest parallel to May Creek. joining May Creek near the confluence with Indian Meadows. The stream now joins May Creek downstream of I 64 th and is hydraulically controlled by a culvert under SR-900. Sediment is primarily deposited upstream from the culvert (Foster Wheeler). The creek lacks a defined channel above the confluence with May Creek. • Greenes Creek enters May Creek west of 148 th Street and currently does not contribute significant sediment to the project area because Greenes Creek discharges to a wetland and the confluence with May Creek is choked with reed canarygrass. Table I: Two year flow for May Creek Tributaries in the Project Area (Foster Wheeler, 1995). Drainage Unnamed Trib. Indian Long Marsh Greenes 0291a Meadows 2 year flow in 23.8* 17 42 26 cfs *USGS StreamStats EstImate Within the project area, Long Marsh is one of the largest flow (Table I) and sediment inputs. The Long Marsh sediment deposits constrict flow and muck movement in May Creek. Long Marsh Creek joins May Creek south of May Valley Road near 150th Place NE. Aerial photography from 1936 shows the creek in a relatively straight channel. The current channel is on the order of two (2) feet wide and several inches in depth at winter low flow. The stream banks are approximately one foot in height, and the surrounding floodplain/fan surface is primarily planted in pasture grass with some recent native plantings. Evidence was found of gravel deposition throughout this reach. Discussions with earlier property tenants indicate that sediment deposition extended into the adjacent pastures following a January 2009 storm event. Long Marsh Creek deposits form an alluvial fan composed of cobble-to silt-sized particles and discharge silt, sand and gravel into May Creek. May Creek channel bottom elevations are higher near the confluence and this channel fiIl is a choke point for flow within the channel. During high-flow events, Long Marsh carries large gravel-sized sediment to May Creek. Before Long Marsh was straightened, the stream would have migrated across the alluvial fan as sediment was deposited in the stream channel. As noted in the previous section, the Long Marsh and Indian Meadows alluvial fans built out into May Valley and forced May Creek around the fan. Doug Chin February 9, 2011 Page 6 Hydraulic model results estimate that the channel capacity to carry bedload and suspended sediment through the project area will be increased after the proposed project by increasing the channel efficiency. Velocities associated with lower flow rates are increased with the removal of vegetation choke points in the channel along with channel- bottom high points that otherwise create backwater conditions conducive to deposition, while depths are increased with a lower channel bottom in conjunction with more water kept in-channel rather than over bank because of improved flow-rate capacity. Reduced overbank flooding into reed canarygrass may allow the annual volume of fine sediment and muck moving downstream to increase on a yearly basis. Higher flow or flood events would continue to carry stored in-chamlel and off-channel fine sediment downstream in a larger pulse, rather then metering sediment at lower flows .. The cumulative total volume of sediment over a longer time frame, ten years for example, would not be expected to change. May Creek bottom sediments were sampled by the King County Department of Transportation Materials Laboratory (King County, May 2010 and October 2010, Appendix B). In the area of 146th Avenue SE the channel bottom is composed on sands and gravels, to well-graded gravel. Larger gravel, cobbles and occasional boulders are also present. In the relatively flat and low-gradient portions of May Valley in the area of 148 th Avenue SE the hard channel is composed of silty-sand and sandy-silt. At the confluence with Long Marsh Creek the hard-channel bottom is composed of well-graded gravel. A variable layer of semi-liquid, organic rich mud (herein referred to as muck) is present within the stream channel behind constrictions in the channel (Figure 3). The muck was sampled 25 feet upstream of a private bridge at RM 4.6. A modified Loss on Ignition analysis (LOI) was performed on the sample and the organic content was approximately 28 percent. This is a very high percent organic material compared to King County streams (Burkey, personal communication). The exact source of this high organic content is unknown; however, the tributary stream channels within the project area do not contain the same muck material and the most likely sources are pastures, agricultural fields and grass/tree litter within and above the project limits. Sources of Stream Sediment Most of the major tributaries to May Valley enter May Creek upstream of 164th or downstream of 146th , outside of the project area. Fromjust below 148th and 164th four tributaries: an unnamed tributary (0291a), Indian Meadows (0291), Long Marsh Creek (0289) and Greenes Creek (0288) enter May Creek. Small alluvial fans occurring at the base ofTrib. 0291a and Indian Meadows identify where sediment is deposited at the valley floor. • A ditch carries Indian Meadows Creek to May Creek. The ditch carrying Indian Meadows has piles of sediment adjacent to the. ditch. These appear to be hand dug sediment piles removed from Indian Meadows Creek (Bauman, personal I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 20 II Page 5 Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited shrubs or trees. Periodic dredging is reported during the 1940s through 1960s (Foster Wheeler, 1995). Property owners may have removed sediment periodically. Sediment Sources to May Creek Agriculture and Pastures In the immediate area ofthe proposed project there are roughly 8.4 hectares of active animal pasture that abut the stream on both sides with a few animal access points to the stream water (assumed watering holes). Under existing conditions, these animal pasture areas are flooded at stream flows below mean annual flow rate (8.6cfs)--over-bank flooding begins approximately at 6 cfs at the low point in the bank. Thus, its likely sediments that may not have washed off during a rain event with overland flow will be washed off when the stream-system capacity is exceeded and floods overbank. After a flood event, there does not appear to be any visual deposition of sediments resulting from the stream itself and upstream conditions but erosion rills are present in the pastures. Thus, it is assumed that sediments suspended in the water column that flush into the pasture retreat back into the stream system. Given this condition with the added animal activity, sediments from soil disturbance would be additive to upstream sediment loads, thus increasing sediment loads downstream. The proposed project goal is to reduce frequency of pasture flooding, thus sediment loads, from a frequency of any appreciable storm to a near one-year storm frequency. To assess potential sediment loads from pastures in the project area, similar studies in the Green River watershed were evaluated (King County, 2007). The Green River studies have estimated sediment loads (via total suspended solids) ranging from 50 to 170 kg/ha/yr; residential = 158 kg/ha/yr, commercial = 172 kg/ha/yr, forest = 110 kg/ha/yr, and agriculture = 50 kg/ha/yr. Literature values (Burton and Pitt, 2002) are significantly different with 10, 420, 3, and 343 kg/ha/yr for residential, commercial, forest, and agriculture, respectively. Monitoring stations used for agriculture land use in the Green River watershed study were downstream of pasture lands in ditches that had significant amounts of choking vegetation in them just upstream ofthe sampling station. Given the relative position of the sampling location and the proximity of vegetation upstream, one may expect the Green River sediment loads to be lower than expected because of the vegetation trapping wash-off loads. Consequently, estimated loads from the May Valley pasture areas are then estimated in the range of 50 -340 kg/ha/yr (assumed 200 kg/ha/yr average). Simplistically if we estimate loads from the pasture lands to be 200 kg/ha/yr, and post-project loads are reduced in half, then for a ten-year period and 8.4 ha, there is a reduction of 8.4 metric tons of sediment contribution to May Creek. An estimated range would be a reduction of 2.1 to 8.4 metric tons of sediment contributed to May Creek. I I I I I I I I I I I I I I I I I I I May Creek, May Valley • Legend Qw-Wetland Deposits Organic Rich Sediment Qvr-Recessional Outwash Deposits Sand and Gravel Qvt-Vashon 1111 Compacted Mix of Silt Sand and Gravel Tpt-Tukwila Formation-Mix of Volcanic and Sedimentary Material 1050 10 20 30 40 Mil •• - ---- - N + Figure 2 ti King County I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 3 There are a number offactors that were not available for the assessment: • The actual suspended sediment loads in May Creek in the project area, the suspended and bedloads from the tributaries and the relative contribution of sediment from different sources are not known. • The change in sediment loading over time due to changes in land use in the basin; logging, development, agriculture and channel dredging is not known. • All ofthe tributaries provide some amount of sediment to May Creek within the valley but the actual volume is not known. Long Marsh Creek delivers gravel to silt sized sediment to May Creek. A depositional area of gravel and sand is visible in May Creek. Estimates of the delivery rate for Long Marsh are made from surveyed elevation changes between a sediment-removal project in 2002 and 2010. • Beaver dams above the project area trap sediment and release sediment periodically due to flooding or breaching. An assessment of the sediment behavior presented here is based on published basin information, aerial photo interpretation, survey data from 1965,1979,1993,2002 and 2010, a soil-loss analysis by Jeff Burkey, sediment samples from the May Creek channel, and May Creek survey records and studies conducted for the project. This assessment provides a working hypothesis about sediment movement in the valley and the basis for future investigations. Background Geology and Stream History The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The valley is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Formation. The formation is composed of volcanic tuff, fine- grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop west of I 46th and forms a physical boundary between the downstream ravine and May Valley upstream. The geologic map is shown on Figure 2. The creek gradient within May Valley is 0.2 percent and the valley is predominately a depositional environment. Aerial photography and Lidar image of the valley show evidence of pre- dredging channel meanders. Historic survey mapping from 1872 shows May Creek as a meandering stream and Tributary 0291a extending north tojoin May Creek just south of Indian Meadows rather than the current confluence approximately 1,440 feet west of I 64th Avenue SE. The alluvial fans from Indian Meadows and Long Marsh Creeks appear on the 1872 map and the mapped location of May Creek is routed to the southwest around the higher elevations of the Long Marsh/Indian Meadows alluvial fans. The historic channel map for 0291a is consistent with Lidar images showing meander scars in the valley. (Aerial photos and historic map information is located in Appendix A). May Creek was dredged to form a linear channel between 1910 and 1936 (Foster Wheeler,1995). A description of May Creek by Bretz (1913) describes May Valley as a "swampy, wide bottomed old channel". A project plan dated 1935 (King County Map Vault) shows creek modifications extending from Lake Washington to I 64th Avenue SE. - - -.. - - -.. .. .. -.. .. .. -.. --.. r.---------------------------------------------------------------------------------------" May Creek Channel Restoration Project Proj eet Vicinity • study Area o Mile Markers Stream Incorporated Areas • Cougar Mountain Wildland Park ~ • '- N ~L 1, March 2010 t.i King County o 95 190 380 570 ...... _ ...... "'"""ood ........ pll •• _-.Iod .. ~C_II" .... _ ......... "'_ ...... iol .. jodlo ... _....-.-........ I4!oec ............... _IUiot ... ,_ ........ ... .......... Io_q-..pIRn&l ............ .,. tI:I ....... fA ..... w.m..to ... 1hiI~ ... otll .... ~ .. db ...... ~poNd. I&oG c ......... ""' ....... too • ..,. .. _ .. t.,...... . .... ct,In ................ ntW 4MYg_ .. 01 ....... but noIlirritMl .. '.t __ ..... I~_ .... * ... tM .... , .......... I ............. -uiooe .... " ..... Anru'eottt. INptllffolmIlIon ""til; .... p ill "",*"" _pi"' ...... ,..mu6u fIIIl(ioog C-*\l Figure 1 I I I I I I I I I I I I I I I I I I I ~ King County Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov February 9, 20 II EXHIBIT 27 ity of Renton fanning Division AUG -5 ZO/1 TO: Doug Chin, Senior Engineer, Water and Land Resources Division, Department of Natural Resources and Parks FM: Julia Tumey, L.G., Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation and Jeff Burkey, Hydrologist, Water and Land Resources Division, Department of Natural Resources and Parks RE: May Creek Drainage Improvement Project: SEMay Valley Road and 148th Avenue SE -Sediment Assessment Introduction This memo provides information on sediment conditions in May Creek from approximately 148 th Avenue SE upstream to 164th Avenue SE. This evaluation addresses geomorphologic controls, sediment sources, sediment behavior in the drainage and how the project actions are likely to influence future sedimentation in May Valley. The purpose of the following background evaluation is to provide information to assist King County Department of Natural Resources and Parks, Water and Land Resources Division in the design process for a drainage improvement project in May Valley. The proposed project location is shown in Figure I. Two questions have been raised regarding sediment associated with the May Valley drainage improvement project: Question 1: Will the project change sediment delivery downstream to May Creek? Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? I I I I 'I I I I I I I I I l I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 6.0. REFERENCES Bicknell, Brian, et aI., July 2005. HSPF Version 12.2 User's Manual. Prepared for U.S. EPA- NERL. Prepared by Aqua Terra Consultants. GeoEngineers, 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid-Sound Fisheries Enhancement Group. Guo, Junke, 2002. "Hunter Rouse and Shields diagram." Advances in Hydraulics and Water Engineering, Proc. 13 th IAHR-APD Congress, Vol. 2,1096-1098. Helsel, D.R. and R. M. Hirsch, 2002. Statistical Methods in Water Resources Techniques of Water Resources Investigations, Book 4, chapter A3. U.S. Geological Survey. 522 pages. King County, 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler Environmental Corp. King County, 2002. May Creek Sediment Wedge Removal Project-HEC-RAS Model. Prepared by Entranco, Inc. King County, 2009. May Creek Sediment Transport Study. Prepared by Anchor QEA, LLC. Otak,2006 USACE, March 2008. HEC-RAS, River Analysis System-Hydraulic Reference Manual (Version 4.0). U.S. Interagency Advisory Committee on Water Data, 1982, Guidelines for determining flood flow frequency, Bulletin 17-8 of the Hydrology Subcommittee: Reston, Virginia, U.S. Geological Survey, Office of Water Data Coordination, [183 p.]. [Available from National Technical Information Service, Springfield VA 22161 as report no. P8 86 157 278 or from FEMA on the World-Wide Web at (http://water.usgs.gov/oswlbulletinI7blbulletin 17B.html). King County 58 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project ~. . ''''''; .-, ~. l" ~~~~" rOO!w ,2 _ 7):, ';, III . @, 233 0,15% 0,15% 0,16% 0,16% 275 0,10% 0,10% 0,10% 0,10% 300 0,072% 0,074% 0,075% 0,075% 350 0,041% 0,041% 0,040% 0,040% 400 0,027% 0,029% 0,028% 0,028% 5.6 Other Considerations Presented in all the scenarios except for Scenario I (existing conditions), the channel bottom profiles were based on survey elevations taken to the harden channel bottom and not on top of the soft sediment. This assumption is based on the fact that after the project when velocities are improved, existing silts will flush out of the system over some period of time, Although in-channel silt mobility analysis indicates improvements will restore competence to mobilize this material, there are in-channel features that will likely retard this process including re-vegetation by aquatic plants during summer base flow conditions, thus changing soil mobility characteristics and estimates of flushing for the next wet season, Lastly, the modeling verification is still in progress. Low flow conditions in the 10 to 20 cfs range should be validated to a reasonable accuracy, but given how well the model simulated for slightly larger flow rates (i.e. > 40 cfs), it's reasonable to assume that the model represents conditions at lower flows acknowledging that there will be numerous specific locations in channel geometry and vegetation blockages not included at every location. However, it is intended to include all major features. At present, the results of the modeling characterize out of bank flows in the 6 cfs range along with the durational analyses estimating that on average over time, pasture areas are flooded on average 3 months out of the year and likely longer. However given the preliminary hydraulic verification, existing channel capacity is uncertain at this time. King County 57 December 2010 I I I -,' I I I I I I I I I I I I I I' I I I I .' I I I I " I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. 5.5 Durations of Flow Rates in the Ravine Using the results in the May Creek Phase II Sediment Transport Study, erosive flows in the ravine were observed to occur in the range of 73 t0340 cfs, and a theoretical estimate of incipient motion approximate to 275 cfs, Refinements for the flow events used in that study, presented in this study, narrows the range of observed mobilization of sediment estimates for incipient motion to a range of75 to 275 cfs (rounding to the nearest 5 cfs), For this study, characterization of changes in erosion in the ravine are based on evaluating durations of flows above the defined incipient motion, As previously mentioned, an HSPF model was used to estimate continuous flows at one hour increments for a period of 60 years (from October I, 1948 through September 30, 2008) using scaled historical precipitation and evapotranspiration, This method enables a statistical characterization using observed historical climate data for May Creek in the valley and ravine that would not be available otherwise, Thus, any phases of dry years, wet years, and everything in between are contained in this analysis as opposed to any potential climate bias using local data of shorter time spans, Durations of flows evaluated in the range of 75 cfs or greater for the ravine show that there are small increases that progressively get smaller the higher the flow rate, Comparing Scenario I to Scenario 8, these increases start with 0,07 percent increase at 75 cfs and become less than 0,01 percent for flow rates at or above 275 cfs, As an example, there is 0,003 percent (Le, 0,00003) increase in duration of flow rates between 300 and 350 cfs, Over 60 years of duration, that is equivalent to 15 hours increase or on average 15 minutes more per year (Table 11). This level of detail is beyond the accuracy of the calibrated model, but any biases in the models would be consistent such that relative comparisons between scenarios like this are valid. Table II Percent of time nows are equaled or exceeded at each of the now rate thresholds for nows in the ravine (catchment CCP) based on HSPF simulation WY 1949 -WY 2008 (525,960 hours). 6 43.26% 43,15% 42,97% 43,00% 10.4 25,06% 24.89% 24,63% 24.68% 28 8,84% 8.77% 8,66% 8.69% 40 6,10% 6,10% 6.06% 6,08% 50 4,60% 4,61% 4.61% 4,61% 75 2.41% 2.44% 2.48% 2.48% 100 1,32% 1.36% 1.40% 1.39% 150 0.47% 0.50% 0,52% 0.52% 175 0,33% 0.34% 0.36% 0,35% 200 0.23% 0,24% 0,26% 0,25% King County 56 December 2010 -------------------------------------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table 10 HEC-RAS calculated shear stress in channel for Scenario 8, mean annual equals 8.6 cfs. Zero shear stresses are highlighted in tan color . w~I-~ --- ~ IMl!IDiJ IMl!IDiJ ~ IMl!IDiJ ~ ti'!iIiI!I;jJ ti'!iIiI!I;jJ w~ ~ ti'!iIiI!I;jJ w~ 4.9926 0.01 0.03 4.6120 McFarland footbridge 4.4550 148th Ave SE Bridge 4.9882 0.02 0.07 4.6112 0.01 0.03 4.4512 0.01 0.03 4.9749 0.1 0.25 4.6067 0.02 0.07 4.4454L ~J 0,01 4.9687 0.53 0.26 4.5754 0.01 0.05 4.4325 0.01 0.04 4.9491 0.04 0.09 4.5628 0.02 0.05 4.4265 0.01 0.06 4.9372 0.03 0.08 4.5516 0.01 0.04 4.4155 0.01 0.04 4.9120 0.01 0.05 4.5429 0.01 0.03 4.4116 0.01 0.04 4.8874 0.01 0.06 4.5323 0.01 0.02 4.3947 1 0 0.02 4.8701 0.29 0.32 4.5144 0.01 0.04 4.3876 0 0.01 Parcel #0223059005 4.8680 footbridge 4.5076 0.01 0.04 4.3783 0 0 4.8658 0.18 0.18 4.5055 0.01 0.03 4.3713 0 0.01 4.8613 0.42 0.12 4.4974 0.01 0.03 4.3694 0 0.01 4.8286 0.02 0.06 4.4821 0.01 0.04 4.3538 0 0.01 4.7885 0.01 0.04 4.4814 0.01 0.03 4.3360 0.04 0.07 4.7495 0.04 0.1 4.4788 0.01 0.03 4.3234 0.06 0.08 4.7207 0.02 0.07 4.4729 0.01 0.03 4.3195 0.05 0.08 4.7087 0.02 0.06 4.4648 0.01 0.03 4.3108 0.14 0.23 4.6403 0.01 0.02 4.4613 0.09 0.14 4.2892 0.04 0.07 4.6226 0.01 0.04 4.2861 0.31 0.21 4.6177 0.Q2 0.06 4.2826 0.06 0.09 4.6138 0.03 0.09 King County 55 December 2010 I I I I I I I I I I I t I I t I I I I I I '1 I I I I I I I I '1' I I I. I I' I I 5.4 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 350 0.02% 0.02% 0.02% 0.02% 400 0.01% 0.00% 0.01% 0.01% Flow Rates Competent to Pass Silts through the System Based on the estimated incipient motion for silts, shear stresses equal to or greater than 0.004 psf are capable to mobilize silty-fines assuming non-cohesive and median diameter size of 0.000328 feet (0.10 mm). Using HEC-RAS computations of shear stress, it is assumed that shear stresses greater than or equal to 0.0 I are capable to mobilize silts. Two flow rate profiles were evaluated for their competency: mean annual flow rates and 29 cfs. The goal was to obtain shear stresses above 0.0 I for the mean annual flow rate of 8.6 cfs throughout the project area. Results show that shear stresses do equal or exceed 0.0 I through the project area except for in the wetland downstream of 148 th Ave SE bridge (Table 10). The threshold of 29 cfs is meant to represent that typically, there is at least one event of that magnitUde each month between November and May-with a few exceptions during dry months. However, barely meeting the minimum target is not optimal given the possible inaccuracies in assuming non-cohesive silty fines. Fines with a diameter of I mm or greater require shear stresses above what the mean annual flow rate can produce. Moreover, during summer months when flows are their lowest, it would be expected that silts will settle on the channel bottom based on these results. This introduces another uncertainty about characterization of the fines when the next wet season starts, If vegetation has started to grow in the channel bottom, the root system will bind the soils together thus increasing the incipient motion threshold. Therefore, it is unclear what levels of flow rates are necessary to eradicate any new growths that may occur in the channel bottom during the summer. These results are also dependant on the relocation of where Long Marsh creek deposits gravels during storm events. This tributary has clearly been shown in the past to deposit enough gravels to effectively backwater May Creek upstream of its confluence. Additionally, shear stresses in May Creek are far below forces necessary to mobilize gravels that are being deposited by Long Marsh creek. King County 54 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project receding waters, this could be interpreted as multiple more months of inundation. Durations of flows flooding the pasture for the proposed design (Scenario 8), shows a significant decrease assuming flows are not out of bank until flows exceed 50 cfs. For this threshold, flooding is expected to occur, on average, 3 percent of the time per year or roughly 2 weeks (Table 9). Again, it is important to note that this does not account for time draining the pastures after an event has occurred, thus the effective reduction in pasture flooding will be less than presented here. Reductions in duration of flooding are likely to occur when storm magnitudes begin to diminish in spring and summer with peak flow rates more likely to be less than 50 cfs. While the other two scenarios are included in the durational analysis and in the table below, the threshold for over topping banks is less than 50 cfs, hence reductions of durations will be considerably less with Scenario 7 (removal of vegetation choke points) the least effective, marginally increasing in-channel capacity to approximately 8 cfs before flows go out of bank. While Scenario 9 (removal of vegetation choke points, some sediment removal) does significantly improve conveyance capacity over existing conditions (i.e. approximately 40 cfs in channel capacity), over bank flows are estimated to occur 33 percent more of the time (i.e. 4 % of total duration versus 3 %) relative to Scenario 8. Table 9 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows passing through the project area (catchment MVL outlet at 148" Avenue SE) based on HSPF simulation WY 1949- WY2008. 6 24.04% 23.77% 23.41% 23.49% , 10.4 13.77% 13.65% 13.44% 13.50% 28 6.03% 6.01% 5.99% 5.99% 40 4.01% 4.02% 4.04% 4.04% 50 2.94% 2.96% 2.98% 2.98% 75 1.39% 1.42% 1.46% 1.45% 100 0.70% 0.74% 0.78% 0.77% 150 0.26% 0.26% 0.29% 0.28% 175 0.18% 0.18% 0.19% 0.19% 200 0.12% 0,12% 0.13% 0.12% 233 0.08% 0.08% 0.08% 0.08% 275 0.04% 0.04% 0.04% 0.04% 300 0.03% 0.03% 0.03% 0.03% King County 53 December 2010 I I I I I I I I I I I I I .1 I I I I I , I 1\ I I I I I , 'I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8 -CCP R 100 Weighted Skew (G= -0.082482) Probability Plot ~ ~~ ~~$~J;~~~ • N M __ ~,§I~·£s __ ~, .. _._._._. ___ .. 1!?.5..:.§:£f§ ___ 'N'_" __ •• _. _ ••• __ • ___ • _____ ~;.-1!'!!' ";!.., ' ~ 0 0 0 g ~ 0 M 0 0 0 0 0 ~ ~ ~ 0 w 0 M 0 ~ ~ N ;; ~ ~ ~ ~ ~ w ~ M N 0 0 0 0 0; 0; 0; 0 0; 0; 0; 0; ci 0 0 Exceedance Probability .. ~ N ;; 0 0 <> 0 0 0 0 0; fi"l.urr. m r"po?Cl.d (,'~ilr'i (.;:ts) lefs) ---------------------- ~O(). Cll ;?~ l(lO.CfJ G!l( ~O. CLl r,15 f,O.1:1l 5911 2!;o.CO ~:;1 :,').r.fi 51; lO.CO 4j~ ~.r.{j :>:,5 .2 .co 2~O 1. 50 :96 1.<:~ :61 l.Cl " -178 95%CI --E)(pected * WeJbull • 2006 • 2004 • 2006 • 1991 • 1990 • 1951 ~l"l H6 bJ3 '" ,),7 5:; ~j~. :;.,~! :.',~. 195 l!l:' " Figure 42 Flow frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) at Coal Creek Parkway (catchment CCP). 5.3 Reduced Duration of Flood Inundation for Smaller more Frequent Events Reductions of durations in pasture flooding are quite substantive given the conveyance improvement from 6 cfs to 50 cfs. Using HSPF, a watershed model was run for a period of 60 years (water year 1949 through water year 2008) at one hour time steps for each scenario. Using the continuous output from the model, a durational analysis can be performed estimating the length of exceedances at any given threshold. It is worth noting that these analyses are a simplification of actual conditions. These results do not take into account the time it takes for the flooded pastures to recede back into the channel after a storm event, thus actual reductions in durations of inundation will be less than presented here, but for the purposes of demonstrating improvements this method is valid. Relevant for valley flooding, the two key thresholds of interest are 6 cfs and 50 cfs where flows are either out of bank or in-bank-post project. Under existing conditions, flows are forecasted to be over bank, on average, 24-percent of the time or roughly 3 months of the year. Which given the episodic nature of storms in the Pacific Northwest, and the unaccounted time for King County 52 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 1 -CCP R100 Weighted Skew (G= -0.12501) Probability Plot J .. ! .. .. t .. .. .. .. .. .. J. J. :il $ J. :!! " :il " 0 <> N N :;! N ~ .. " ~ § 704.1-cfs ... '> ------------------.-.--------------;~-, _. __ . __ . __ §2~J.:f!!_. __ .. __ . __ ._. __ .... ___ .... __ ._ ... _ ..•...• -.• --...... -.. -.. --.... ~'!.'.' ...• 1.' ____ 431 4.C~ __ . _______ ._____ .... '" I .. .~. ...... .. _ .. _ .. ___ ._ .... _~.§~?..:f~ __ ._ .. _____ ._._._. __ . __ ._. __ . _____ . ___ ~ ".,.,'... g ______ ._._}~~.:.4~ _______ . ____ --;.,_: .. I § g o 0 III N'" o o N o Exceedance Probability ~ 0 ~ ~ ~ o 0 0 00 I<"t.urr, m r,,!=(><:Ld (year) (o;;ls) Ic[s) .---------.----------- ~oo.co 7tE' l('O.CO '0' SO.CO 6/1 I,,,,cn 5'<'. 25.CO ~j9 :O.CO ,,13 lC, CO 4:31 ~ .to ~H 2. CO l:;~ 1.5r, ~ [if, 1. 2~ :~9 l.CI G7 _178 95%CI --Expected * Weibull • 2000 • 2004 • 2000 • 1991 • 1951 • 1990 tl29 72" o4~ lit:) ~!i:J ~:3 no ~,.~~ ~29 1,11 Hi 6~ Figure 41 Flow Frequencies using USGS 17-8 methodology for existing conditions at Coal Creek Parkway (catchment CCP) King County 51 December 2010 I I I I I I' I ·1 I I ,. '. I I i I I I I I t I I. I I I I' I, I I I ~ • " " ~ " , c c " 10' m m 0> 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario a -MVL RaO Weighted Skew (G= -0.12543) Probability Plot 560.7-cfs 353.7-cfs _____ 289,~!S ____ .. __ ~ ______ . ___ .. ___ ;=""~: .' " " ____ 195,~~-C~~L_ __ 0 0 0 g ~ 0 M 0 0 0 0 " m ~ 0 w g M i'l " ~ N ~ m m w w M 0 0 0 .; .; 0 0 0 0 0 .; 0 0 0 Exceedance Probability ~ N :; 0 0 0 0 0 .; 0 .; l<<'Ilur'" m E"Ff'C~d (yean tel ~) I ::tsl ----------------------:'OC.C() 62' 1(\0.(:0 '" 50.CO H'ti t.O.r.O 411:1 4!~.C(1 4.36 :O.r.O 4U; 10. CO l!.>' 5.CD '" 2. CO :(.~ 1.50 :~~ 1.,z", : )0 I.el 61 _178 95%CI ---E)(pected * Weibull • ,200<1 • 2004 • 2008 • 1990 · '''' • 2007 6~,1 51: ~13 ~ (.:1 H~ 1.c~ 3~ I ::(J~ H!.> lSE 12~ " Figure 40 Flow Frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) for flows drainging to 148th Aveneue SE. King County 50 December 2010 --------------------------------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 1 -MVL RBO Weighted Skew (G= -0:15274) Probability Plot ~ 1 ~ ~ N M _._ .. _. ____ .,J:EJ_"Q;s:!.lli __ .... _ ... __ .. _ .... _ .. __ ... __ . __ .. _ ... __ ._ .. _. __ . ___ . ___ .. _ .... _ ... __ . ___ .. _ .. ~:~_ .. _ .. _ ... _. ____ ... _,t~.~.J.:£~ __ .... _ .. _ ....... _ ... __ ._._ ... __ . __ .... _. __ ..... __ ._._. __ ._ .. _ ... _ ..... _ .. _ . ....t~. ________ 1!?~Y._cf!l; __ ._ .. _ ... _ ... _________ ._. ___ . ____ _ ------.R~L.--------------_:_;i,rtr ,;- '" $ • Ir ~ ~ .. 0 c c 10' <{ § B~a~ij o o 0 0 00 Exceedance Probability Ii€Lurr, 173 r.~~ecld (Y~i'.r) (cisi Iclsi ------------------_ .. _- :OO.CO 6)~' 1(10.CO .~71 50.CO :;O~ I,O.r.n 1f11 2!:>.(:O 4:1101 :!O.r.O 117 10. CO ~'.>1 !' .CO '" 2. co :P'1j 1.50 :1q 1. 2::. :~O 1. Cl :;: _178 95%CI --E:r:pected * Weibull • 2008 • 2004 • 2008 • 1991 • 1990 • 1951 6'1 ~,.:) ~~:) ~ ,.~, H7 ~~5 )!.o'.> 2S6 WE> 11, e 118 " Figure 39 Flow Frequencies for existing conditions using USGS 17-8 methodology for flows at 148th Avenue SE (catchment MVL) King County 49 December 2010 I I I I I I I I I I I I I I I I I ,~ I I I I I. I I I I' I l- I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2 229 256 206 240 266 217 5% 208 5 349 400 310 355 404 319 2% nla 10 431 508 378 435 506 384 1% 357 20 513 618 442 512 609 446 0% nla 25 539 654 463 537 643 466 0% nla 40 594 731 506 590 716 507 -1% nla 50 621 769 526 615 751 526 -1% 514" 100 704 889 588 694 864 586 --1% 582 "Flows were interpolated and extrapolated from published 2, 10, and 100 year flow rates in the May Creek Current and Future Conditions Report. Additionally with the proposed improved channel conveyance, attenuation of flows is marginally less thus slightly increasing flow frequencies on the lower end with the I year event increasing from 54 cfs to 61 cfs (Figure 40). Flow frequencies in the ravine were similarly indifferent between existing (Figure 41) conditions and proposed (Figure 42). King County 48 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table 7 Summary of flood frequencies for Scenario I and Scenario 8 for May Creek in the valley. . 1.01 53 64 41 61 73 48 16% 110 1.11 94 108 80 104 118 89 11% nfa 1.25 120 135 104 130 145 114 8% nfa 1.67 163 182 145 173 191 155 6% nfa 2 186 208 167 195 216 176 5% 165 5. 283 326 252 289 329 259 2% nfa 10 351 414 307 354 412 312 1% 285 20 417 503 359 416 496 362 0% nfa 25 438 532 376 436 523 378 0% nfa 40 483 595 410 478 581 411 -1% nfa . 50 504 625 426 498 609 426 -1% 413 100 571 722 476 561 698 473 -2% 468 . Flows were interpolated and extrapolated from published 2, 10, and 100 year flow rates in·the May Creek Current and Future Conditions Report. Similarly for the ravine, these changes in flood events are nearly the same. The 2 year flood event increases from 229 cfs to 240 cfs (5%). Flood frequency magnitudes decrease starting around the 20 year event. Again, this estimated change is within the 95% confidence range of existing conditions (Table 8). Table 8 Summary of flood frequencies for Scenario 1 and Scenario 8 for May Creek in the ravine. 1.01 67 81 52 78 92 62 16% 141" 1.11 118 135 100 130 147 112 10% nfa 1.25 149 167 130 161 179 142 8% nfa 1.67 202 225 180 213 236 192 6% nfa King County 47 December 2010 I I I I I I I I I I I I I I I I, I I ----_._------------------------------ I I I I I I I I I I I I I I I I I I, I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project §: 6 1 w MayCreek Exisiting Condition Plan: 1) KC_SCN_1 4/1/2010 2) ~"._O"N_" Mainsem Figure 38 Water surface profile at 50 cfs for Scenario 1 and 9. 5.2 Updated Flow Frequencies 41112010 LOB ROB Ground Original flood flow frequency estimates in the May Creek Current and Future Conditions Report were based on a 42 year period of record from water year 1949 through water year 1990, and a single scalar to translate SeaTac precipitation to May Valley conditions using Bulletin 17-B (USGS 1982). As previously mentioned, current hydrologic analyses include additional data through water year 2008 (18 years more data). This combined with the updated FTABLES for existing conditions, and flow frequencies have changed since the original analysis was done in the May Creek conditions report. Frequency analysis was done for two locations in the basin, flows draining through project area to 148 th Ave SE bridge (Figure 39) and flows down to Coal Creek Parkway. This illustrates how estimates of flood frequencies are dependant on period of record in addition to magnitude of events and any small changes in frequency estimates should be viewed with that understanding. Through the valley area, the magnitude of the 2 year flood frequency increases from 283 to 289 cfs (5 %). The increases in changes between Scenario I and Scenario 8 diminish to no change between scenarios at the 20 year event. In fact, flood events greater than the 20 year event decrease after the project. It is also worth noting that all the changes either increasing or decreasing are within the 95% confidence interval of existing conditions (Table 7). For convenience, the original May Creek Current and Future Conditions report flood frequencies are included in the table. King COllnly 46 December 2010 Hydraulic and Hydrologic Analyses oj the May Creek Channel Restoration Project Scenario 9 The alternative scenario of removing sediment and choking vegetation to an elevation of 309 feet (Scenario 9) is less effective at keeping flows in-channel at 50 cfs through the project area (Figure 37). However flows are estimated to stay within bank between l48 th Ave SE and at the footbridge downstream of Long March creek confluence. However, this is primarily because of the element of removing vegetation choke points and the assumed flushing of existing silts with the increased velocities. Again, convergence of the water surface profiles converge at the natural control of wetland outlet (Figure 38). It is worth noting that flows are maintained in channel through the pasture areas up to approximately 40 cfs. MayC" ... k Em,ling CondItion NAVD88 Plan: 1) KC_SCN_9 41112010 41112010 ··---Jl #022305900 McFarland Footbridge ,,~,~ 148 th Ave SE Bridge Figure 37 Perspective plot for Scenario I and 9 overbank flooding with 50 cfs at 148th Street. Dark blue areas are for Scenario 9, light blue are for Scenario I (existing conditions). King County 45 December 2010 I I I I I I I I I I • I I I I I I I I' I I I I I I I I, I I I I' I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project In addition to lower flows, a review of higher flows was done, Focusing on downstream of the wetland through the bridge located at I 43 rd Ave SE, the same return period of flood frequency was used, but with their respective flow rates of 229 cfs (Scenario I) and 240 cfs (Scenario 8) for the 2-year return period through the ravine, There is a marginal increase in water surface elevations downstream of 146 th Ave SE of 0,08 ft and diminishes to 0.05 ft at 143 rd SE (Figure 36). More importantly, the velocity changes are minimal as well with 0.10 ftls at 146 th Ave and 0.06 ftls down at I 43 rd Ave SE. This marginal change in water surface elevations and velocities are essentially within the accuracy of the model validation. Thus, no effectively apparent significant changes between existing and proposed conditions at this flood frequency. Moreover, selecting any higher flow rates will result in even less differences between pre and post conditions. ·~~··t~-·~---.-.-.------WS 2-)'811' a· 2ylScn6 ws 2-year a -2y,scn1 Ground Figure 36 Water surface elevations for the 2 year return period (229 and 240 cf,) for Scenario I and 8. King County '44 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project MayCreek Exisiting Condition NAVD68 Plan: 1) KC_SCN_1 4/1/2010 2) Kv ~\,N 0 41112010 Mainstem € 6 1 w Figure 35 Water surface profile at 50 cf. for Scenario 1 and 8 King County 43 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8 Under the proposed project design, Scenario 8, with vegetation removal and sediment removal down to 308 feet for approximately 1000 feet, the conveyance capacity increases to approximately 50 cfs in the previous sections where 6 cfs would be out of bank. This improvement effectively mitigates storms near the I-year magnitude (i.e. 61 cfs). Figure 34 shows that for 50 cfs, May Creek is over bank for existing conditions in the entire project area while for Scenario 8, flows are kept in-channel until the wetland area downstream of 148 th Ave SE (shown in dark blue). Hydraulic controls in the system coalesce down to the outlet of the wetland entering into a well defined channel 'leading to the ravine, with a small difference in water surfaces through the wetland area as a result of removal of vegetation choke points (Figure 35). One of the primary choke points to be removed affecting upstream of 148 th Ave SE is the ' combination of canary reed grass and clumps of Willow trees encroaching in the channel just downstream of 148 th Ave SE-significantly reducing channel capacity. -----1i #022305900 McFarland Footbridge' 148 th Ave SE Bridge Figure 34 Perspective plot for Scenario I and 8 overbank flooding with 50 cfs at l48th Street. Light blue areas are inundated areas for Scenario I and dark blue are Scenario 8. King County 42 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project With only a water surface reduction of half a foot through the study area, conditions upstream of Long Marsh are clearly unimproved given flooding still occurs at the mean annual flow rate (Figure 39). Furthermore, storm flows may begin to overtop downstream of Long Marsh depending on the magnitude of the event again not meeting project goals. MayCreak €xis;tong Condition NAV088 Plan: 41112010 U49111 ~ 1 #022305900 ~ McFarland Footbridge ----l 148 th Ave SE Bridge ~ I Figure 33 Perspective plot comparing Scenario I and 7 under mean annual flow rates King County 41 December 20/0 I I I I I I I I I I I I I I a' I I I I I I: I I I I I I I I I I I I I I I I I € 6 j w Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project MayCreek Exisiting Condition NAVD86 Plan: 1) KC_SCN_1 4/1/2010 2) ~"_o,,,,_, Malnsam 4/112010 Main Channel Diltance (ft) legend WS In Chnnl 50 ds· KC_SOII_' WS In Chnnl 50 cfs-KC_SCN_7 • Ground LOB ROB Ground Figure 32 Water surface profile at 50 cfs for Scenario I and 7 King County 40 December 20 J 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 7 With complete removal of encroaching canary reed grass and Willow trees, flows are kept in bank between 148 th Ave SE and at the footbridge just downstream of Long Marsh Creek (Figure 31). However, this is predicated on the fact that all the silty fines are flushed out of the system. Without that successful element, in-channel capacity will be greatly reduced and more representative of existing conditions (Figure 32). One of the most effective choke points to be removed is just downstream of 148 th Ave SE. The combination of canary reed grass and Willow trees significantly reduce potential channel capacity at this location and a few others further downstream. MayCreek Exi .. tinll Condl1ion NAV08B Plan: 1) KC_SCN_7 41112010 41112010 ··---;l #022305900 McFarland Footbridge 148 th Ave SE Bridge Figure 31 Perspective plot for Scenario 1 and 7 (vegetation removal) 50 cfs at 148th Street. Light blue are for existing conditions while dark blue are for Scenario 7. King County 39 December 20 I 0 I I I I I I I I I I I I I I I I. I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project MayCreek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment \04 4/112010 Legend WS mean annual 318i-------~~------_+--------~--------~---------~-------1 Gro~nd LOB 316i------~~------_+---I-----~--------+_------,.---~-------1 --ROB .... I .... /~ , /' / 1\< ITf ~ /\ .r" € 311 ,I . 6 I-- j 7 w / , -1 , fi Figure 30 Longitudinal plot for Scenario 1 (Existing Conditions) water surface profile for mean annual flow rate. King County 38 December 2010 ,---------------------------------------------------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 5.1 Improved Channel Conveyance Hydraulic analyses using HEC-RAS estimate that Scenario I (i.e. existing conditions) flow rates as low as mean annual (8.6 cfs) over top banks inundating pasture lands (Figure 29). In fact, channel capacity estimates for a few sections show that flows can go out of bank at rates as low as 6 cfs for existing conditions (Figure 30) while Scenario 8 (later in this section) keeps flows in channel up to 50 cfs. Thus calculations for evaluating improved conditions in May Valley are based on this threshold of flows between 6 and 50 cfs, such that any improved conveyance capacity will reduce the frequency and duration of minor storm events flowing out of bank. May Crlltlk Exisiling ConditIOn NAW88 Plan: Sce ..... no 1: KC ExrU"" With Sedimanl ~~~:.:: ..... ·---;l #022305900 McFarland Footbridge . Figure 29 Perspective plot for Scenario I (Existing Conditions) mean annual flow rate (8.6 cfs at 148th Street) King County 37 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek ed"ing Condition NAVDBB Aan: 1) KC_SCN_B 4122/2010 2) KC_SCN_1 412212010 J<> . RS=4.114 BR Bridge#1143RDAVENUE ~B) I . I· Lagend / WS 100-yrcur. -KC SeN 8 WS 100"",cu: -KC SCN..1 • Ground • 320 / Ineff • Bank 8ta "--315 ~ ~~ g 6 j r-------w .-/ 1\ -310 I 0 100 200 3'10 4;0 Station (ftl Figure 28 Water surface elevations for the 100 year return period (Current Conditions) at bridge crossing at 143rd Avenue SE for Scenario 1 and 8. King County 36 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Capacity at the bridge located at l46th Ave SE show that the I OO-year (Conditions Report) flow rate does go overbank (left side looking downstream) under both existing and proposed conditions and at the same elevation. Again it is worth noting that under the proposed project, the magnitude of the 100 year return period decreases, water surface elevations post project will be less (Figure 27). Similarly, the bridge downstream at 143 rd Ave SE shows to have capacity to pass the 100-year pre and post project (Figure 28) as well. It is worth noting that the bridge geometry used for I 43 rd Ave SE is based on previously existing geometry from the previous HEC-RAS model. A survey crew is scheduled to resurvey this bridge and confirm existing geometry from previous modeling efforts. g 6 1 w May Greek Btis,ing Condition NAVD88 Aan: 1) KG_SaC8 4122/2010 2) KC_SCN_' 4122/2010 RS = 4.28 BR Bridge #2 146TH AVENUE (RM 4.280) 1-----.08 -1-041 .08 -I,--_~~_-, Legend 3201-----'f-------+------t------,~----WS 1 OO-yr cur .• KC_SeN_B ·315i---~d-----t_-~;::::.,¢+---~-t_--- 100 200 300 400 Station (ft) -S 100-yrcur. -KC_SCN_1 • Ground • Bank Sta Figure 27 Water surface elevations (Scenario 1 and 8) for the 100 year (Conditions Report) at the 146th Ave bridge. King Counly 35 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project g i w Figure 26 Water surface profiles for the 100 year flood event for Scenario 1 and 8. King County 34 . December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Estimated hydraulics for Scenario 8 elucidate that the control points effectively move down to the transition of the wetland to a channel entering the ravine for lower flows (Figure 25) and for high, infrequent flows (Figure 26). This characteristic supports the results of no increases in erosive flows to the ravine before/after the proposed project for the same flow rates. g i w Figure 25 Water surface profiles at 50 cfs for Scenario 1 and Scenario 8. King County 33 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I 'I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project € j w : , .. • d ~ '. ~ s s • s i! I I ~ f i : " I " " ~6 ij ! ,~ S! ~ , 0 ~ ~ 0 I ij' D:'. " " iii iii , .. . ' I! ! J! i. I i. H " . • • • • ~ • • ~ ~ ~ . ~ ~ , ~ H , m m m m m 0 o 0 ,~ 0 0 .' • • • • , u m ~ ~U~ . j " , ~. ~ ~ I , • " .fi-ioi , , , •• • • '" 26000 Figure 24 Water surface profiles for the I-year (Conditions Report) for Scenario I and 8, Red circle highlights the convergence of profiles at 146th Ave bridge. Secondarily, removal of vegetation choke points in the wetland show a few tenths change in water surface, but given the model accuracy and very small amount of lost storage, this natural land form downstream of the proposed restoration channel activities will greatly control potential changes in erosion in the ravine, and less control from the bridge at 146 Avenue SE. In the following sections, three scenarios (plus existing conditions) were focused on for evaluations: • Scenario l-existing conditions, • Scenario 7-removal of vegetation choke points, • Scenario 8-removal of vegetation choke points with increased sediment removal, and • Scenario 9-removal of vegetation choke points with some amounts of sediment removal. As previously mentioned there are three main control points in the system under existing conditions: I) the natural transition from valley to a ravine, 2) vegetation choking the channel downstream and upstream of 148 th Ave, SE, and 3) sediment depositions upstream of 148 th to the confluence of Long Marsh Creek, Each of the proposed scenarios improve in channel conveyance to varying degrees of success with Scenario 8 resulting with the ability to maintain waters in channel up to approximately 50 cfs for properties upstream of 148 th Ave SE, King County 32 December 2010 -------------------------------------------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 5.0. RESULTS Summary of results include assessments of existing and proposed channel capacities, changes in flood frequencies and durations, stream competency to mobilize fines, and changes in erosion in the ravine. Reviewing existing conditions, it is apparent where hydraulic controls are located in the system (based on available survey data). During mean annual flows (8.6 cfs through the study area), control points are vegetation choking points in the wetland downstream of 148 th Ave SE bridge and mildly so upstream of 148 th and gravel deposition where Long Marsh enters into May Creek at approximately river mile 4.64, just upstream of a footbridge: This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04 (Figure 23). Similarly for higher flows (e.g. I year event), Long Marsh again controls water surfaces upstream for the same reach length. Figure 23 Scenario 1 (existing conditions) water surface profile for mean annual (filled in water surface) and Conditions Report 1 year event (blue line with symbols). However, downstream of 148 th model runs show a convergence of water surfaces for the same flow rates for pre (Scenario I) and post (Scenario 8) project based on the transition from a valley to a ravine: This abrupt natural constriction changing from open wetland on valley floor to a well defined channel en.tering into the ravine become. more controlling the larger the storm event. While water surface elevations may be lower for Scenario 8 in the wetland for the same flow· rate, water surface elevations approaching 146 th Ave bridge converge to the same elevation (Figure 24). King County 31 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 4.0. SEDIMENT TRANSPORT A particle size distribution was not performed for stream reaches in the valley floor; however, during field visits, it was noted that much of the channel bottom is extremely soft-in some places up to 3 feet of muck. Given the amount of bank vegetation and slow velocities, the soft sediments are likely made of up fine silts and organic matter from decaying vegetation. Given this condition, the particle size distribution (Dso) used for incipient motion in the valley channel was assumed to be 0.10 mm diameter (0.000328 ft). Aside from the percent of organic matter and possible colloidal conditions, incipient motion was calculated assuming the sediment is non- cohesive in nature and made up of mostly silt. While Shield's curve is nearly constant for substrate sizes larger than 5 mm (Re* -400), it varies with smaller particle sizes. Thus it was necessary to compute the particle Reynolds number to obtain the Shields value (Guo 2002). Using a particle diameter of 0.1 mm, translates to a Re* approximately equal to 1.1, and Shields number of approximately 0.10 (Figure 22). Hence, the computed critical shear stress of less than 0.0 I psf is estimated for silty fines. '" " 1 ]! 0.1 .c III 0.01 . -. - .~ - - - - 0.1 Guo-Shields Empirical ~-I f.= .-.---. . --, :.=e-lm· "- 1 10 100 Re* Figure 22 Guo-Shields Empirical Curve In Hec-RAS, the shear stress is computed with the following formula: r=;RS, where R is the hydraulic radius, and S is the energy slope. King COllnty 30 1000 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: 1) KC_SCN_1 2) KC_SCN_8 RS::: 4.622613 V ~ Legend • Ground -KG_8CN_B • ank Sia -KC SeN • Ground· KC_SCN_1 31. • ank Sia -KC SeN 1 312 g V 6 ~ ~ .. UJ 310 308 I 200 250 300 350 Station (ft) Figure 21 Typical Channel Geometry of existing (black line) and proposed (fuschia line). King County 29 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I, I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 9: Removal of vegetation choke points and some sediment removal Approximately 518 ft of sediment (125 ft upstream, 393 ft downstream) of McFarland footbridge is assumed to be removed to an elevation of 309 ft. This elevation was selected to be similar to historical channel bottom elevations leading down to 148'h Avenue SE bridge crossing and to evaluate an intermediate alternative. fvlayCreek Exlslting Condition NAVD88 Plan: 1) KC_SCN_1 3/25/2010 2) KC_SCN_9 312512010 23400 23600 23800 24000 24200 24400 24600 Main Channel Ilsance ) Figure 20 Scenario 9 showing existing conditions and proposed profile after sediment removal (309 ft) and flushing of silts. 3.1.2 Typical Channel Cross-Section Typical Channel Cross-section within the sediment removal segments was simplified for this study to assume existing channel geometry with the bottom dropped to the proposed elevation. In final design, sections where excavation exceed 2 feet below top of sediment, channel banks will be given side slopes to prevent bank sloughing. This simplification represents a conservative side of expected as-built conditions given the addition of side slopes will slightly increase channel capacity. King County 28 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8: Removal of vegetation choke points and increased sediment removal This is the most aggressive scenario with sediment removal assumed to occur between just downstream of l48 th Ave SE bridge to the 125 ft upstream of McFarland footbridge-in total approximately 1025 ft at an elevation of 308 ft. The elevation of 308 ft was selected based on the apparent historical channel bottom at 148 th Avenue SE bridge crossing. May Creek Exisiting Condition NAV088· Plan: 1) KC_SCN_1 3/25/2010 2) KC_SCN_8 312512010 MayCreek Maln!tem I I Legend • op 01 5adlmen ! -_.- LOB ---- 315 ROB ----=J \ _______ lChannel Grade / ' 1-----~',-~ ----// k ~-L':~ ~ /! l \ ~->7' --r ITfF --~-~ ---' L_,~ __ ~\/ 11t~f nifl III i I I 310 -J I g 6 1 I w ~ ~ -a ~ • 305 t ~ O __ J' m ~ ~ ~'" ~ ~ ~ ~ -E ~~ ~ ~ ~ . • II iI ~ I j iii Hi ;3 ~ "':"1' i.<:: flf > > Ii f n E! , , f ~ ~ ~ ~ ~-l~ Ii ~ ~ ~ ~ A Q Q Q 300 -;~_i;;l~~ a-I ~ ~ ~ ~~ m ~ I ~ ;:;~ ~~ i9 ~ ~. i ~ ~ • ~ ~ n $~ ~ ........ In 1R<t ~" ~ ~ ~ ~~ ~ :;,~ ~.J ~:,~:, '<1:'<1: ~ ~ ~ ~ .,., ~, ~. ~, " ~, " ~, ~, .¢, -i, ~..r, ~. 23400 23600 23800 24000 24200 24400 24600 Main Channel Disenea (II) Figure 19 Scenario 8 showing existing conditions anil proposed profile after sediment removal (308 ft) and flushing of silts. King County 27 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 7: Removal of vegetation choke points This scenario represents enhancements to the channel conveyance capacity by assuming Reed Canary grass is removed from the channel and banks, and Willow root systems are removed from the channel. The assumed channel bottom for this scenario and subsequent scenarios are based on the harder substrate sediment. This is based on the calculation of critical shear stress of silts in the channel and steam competency to mobilize the silts (see Section 4.0). May Creek Exlsiling Condition NAVD68 Plan: 1) KC_SCN_' 3126f2010 2) KC_SCN_7 3/26/2010 Ma)CrlMlkMainll:am 320 ! I I I I J-· , . -.- 315 ---------H - , , \ '. /~ \ --" -' -"':------ I "" -:J ~ // \ ' ...... /' r, !" I' {",. \ ''1 1-,' ~-' i I 1 '-Pf . , .. c-> r- "j\ / I ;;-' ,'" ~ ~ / " /'" +.,,-'l,!! I I /."I A s 1 '" / \. I\~H~" rifffLnmiV . w , '~I I I J 1++1 ~ I , Jttq I ' . " ,I 1\ I I' ~ ~ •• If I~~ I' 'II I I!i II I iii iii i i ID pi s. I I ssaa .a.!l. I" f----. 305 ~-......,1- R, RR R R I'll<! t R ! R R R fa R R l~ ~;; ~ I U I U Ii: I I I I.. i I II d n i iii i!ii I ill iii iii i i .! ~. ~ ~ ..,. (I) U)U) If) (I) $it <lUI) VJ Vol (1.1 (I) (f.I III (I) ~~ • , , ~I JJ ~! ~~ ~ ,~ ~~~ ! I I ~ I ~ ~ ~ ~ ~ j~ I ~f ! ~ 1 ~ ~~§~r·niw~·m0i~" ~iipnF~~ ~E ~ ~, , c ~~~~J~ .. ,.J~~~ ~~ ~ ~ ~ ,~~ .. ~~~ S! ~ ~ .,., "" ... , ... , ........ ,~ ... , ",,,,,~.,,,,,~, .. , "" ... , ... , ","','" ... , ... , ....... ,..,., ... "',.,.,., ~.n. :ri. 300 22000 23000 24000 25000 26000 27000 Main ChaOflat OIltancQ (ft Figure 18 Scenario 7 longitudinal profile in study area. The black line is channel bottom using top of sediment (used in Scenario I) and fuschia color line is profile of channel bottom to firm sediment. King County 26 December 2010 I l~.nd -Top of Sed, LOB ---- ROB -ChMI atm. Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 3.0. SCENARIO DEVELOPMENT Hydraulic scenarios were designed with changes in channel geometry representative to the three proposed channel improvements: 1) removal of choking vegetation points, 2) removal of choking vegetation points with increased sediment removal to an elevation of 308 feet, and 3) removal of choking vegetation points with some sediment removal to an elevation of 309 feet. 3.1.1 Model Geometry Scenarios were designed to characterize existing and proposed conditions in the valley. The first scenario includes characterizing existing conditions, and three other scenarios were designed to evaluate increasing levels of channel modification to address the objectives. The naming of the scenarios are representative of the stepwise process of developing the geometry files to get from one scenario to the next in HEC-RAS rather than suggesting that multiple additional scenarios were evaluated but not presented in this report. Scenario 1: Existing conditions Survey work done in January 2010 included two channel bottom elevations: on top of soft sediment, and harder substrate assumed to be the more historical channel bottom. Existing conditions is meant to represent current channel geometry with channel bottom defined as on top of soft sediment. King County 25 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project could be as high as surveyed. To reproduce those elevations for those low flow rates, the McFarland footbridge would have to be nearly completely damned to backwater upstream that high. While it is not known if this may have happened, it again seems unlikely. Therefore, while the accuracy of the survey data is not in question, the combination of assumed accuracy in flow rates and the edge of water survey in flooded conditions appear to represent a set of conditions neither characterized in the model configurations nor explainable in their . contradictions. Therefore those two dates of observations should not be considered part of the validation. Conversely, model accuracy seems to be quite good for larger storms with error less than or equal to 0.50 feet. However, further model validation is still being pursued at this time targeting storms in the range of 10 to 20 cfs. King County . 24 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project March 30, 2010 Observed Water Surface Elevations In an attempt to capture water surface elevations for smaller storm events, another site visit was conducted. Water surface elevations were obtained by taping down from top of bridge. Additionally, flow rates were estimated using standard methods and velocity meters at each water surface observation point. Observations were made at three locations, l48'h Ave SE bridge, McFarland footbridge, and parcel #0223059005 footbridge with their respective estimated flow rates of 45 cfs (poor quality), 48 cfs (good quality), and 40 cfs (good quality). Long Marsh creek enters in' upstream of the McFarland footbridge, hence the increase in flows at that measurement. Using these field measured flow rates, model accuracy validates with good accuracy with the greatest error equal to 0.50 feet. A water surface profile and observed water surface elevations is shown in Figure 17 below, and previously in Table 6. May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment 'v4 4/112010 € j w Figure 17 Observed water surface elevation for March 30, 2010 at 48 cfs at three bridges. 2.4.4.1 Validation Summary WS 48 efs • Ground LOB ROB This validation shows that the model under predicts water surface elevations for lower flows in the Valley floor anywhere from 0.06 feet to 1.3 feet (assuming calculated stream flows are accurate, but appear suspect) with most of the differences in the range of 1.0 feet and has better accuracy with higher flows (e.g. 48 and 64 cfs water surface observation). One hypothesis has been presented to partially account for the discrepancies, however there are multiple other plausible causes for the elevated water surfaces for low flows: some of which might be, error in gauge flow estimates at 37G, or unaccounted for choke points in the channel. At present, assuming the flow rate estimates are correct, it is very unlikely that water surface elevations King County 23 December 2010 I I I I -I I I I I I I I I I • I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project January 14, 2010 Water Surface Observation A second observation of water surface was made during the larger storm event between the two survey dates on January 14,2010 I :00 pm, at Parcel #0223059005 footbridge (tape down from top of bridge was. used). Using the gauged flow rate at 148'h Ave SE bridge of64 cfs, the water surface profile was within a two tenths ofa foot to observed (see Figure \6). May Creek Exisitlng Condition NAVD88 Plan; Scenario 1; KC Existing with Sediment \4 10 WS 64cfs·Jan14 31B~----'-----~------~---------+---------+---------b---------1I • Ground 6 1 w LOB ROB , 64 cfs-Jan 1 Figure 16 Observed water surface elevation for January 14,2010 at 64 cfs at Parcel #0223059005 footbridge King County 22 December 2010 Hydraulic and Hydrologic Analyses ojihe May Creek Channel Restoration Project Figure 15 Example of overbank flooding slowly draining back into channel after a storm from 7 days prior (with some minor precipitation 4 days prior). Photo taken 3119/2010. King County 21 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment v4 312412010 RS = 4.974923 .065 'I . I' .065 ,J \ 0 legend 320 \ 5 4 6 WS 40 cfs • Ground • Bank 8ta • 318 \ OWS 40 cfs 316 g \ 6 i w 314 ""-I ----B~ ~ J 312 I , 200 300 400 500 600 Station (ft) Figure 14 Example of cross-section where water surface elevation is same elevation as bank elevation (RM 4.974). Obstruction in cross-section is representative of dense canary reed grass on the banks. King County 20 December 20 J 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Reviewing the surveyed water surface elevations shows that for those two dates, the elevations are virtually the same with the exception of the lower most point a halffoot lower (associated with the 29 cfs date) than the rest. This does present an inconsistency between the calculated flow rates and expected water surface elevations. With flow rates on January 22 less than half of what was estimated for January 8, one would expect the water surface elevations to be lower on January 22, when in fact they appear the same or higher with half the associated flow rate. MayCreek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment IA 312412010 =======~========~M:'J~[''':k:M.:;": .. :m~===I==========I=========~:I~~~~~I Legend 316 -~-r--'. Gro:nd 1\1 ___ -=L=O.==_-, jl ~ 24500 25000 25500 26000 26500 Main Channel Dis.anea (II) Figure I3 Profile of observed water surface elevations for January 8 (downstream of footbridge) & 22 (upstream of footbridge) with left and right bank elevations (LOB, ROB) plotted. In addition, in the area where edge of water was taken, overbank ground elevations are lower than bank elevations effectively creating a bowl outside the channel. This is consistent for about 570 feet (RM 4.88 through 4.99). The observed edge of water was either very near bank elevations (i.e. depressional area filled with water) or up to a halffoot above assumed bank. elevations (see Figure 14). Given the combined circumstances of inconsistent water surface elevations relative to flow rates, and the overbank depressional areas, conveyance out of bank in the pastures likely will behave in a couple of different fashions. When flows are initially going over bank, the flow pathways will act like a branch in the stream with its own water surface profile until it rejoins the mainstem. Then as flooding waters increase, the whole valley acts as one conveyance. As the storm recedes, the overbank flooding areas begin to behave like a slow draining lake (see Figure 15). Each of these conditions has a different hydraulic characteristic that may yield these inconsistent out of bank water surfaces for a given estimated flow rate. King County 19 December 2010 I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration,Project I 70 I ~o I 50 I ~ 40 GI ... I .. '" ~ 30 il: I 20 I 10 I 0 I .... .... .... .... .... .... .... .... .... .... .... ........ I-'~~""''''''''''' .... .... .... .... .... .... .... .... .... .... .... .... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ........ ........ ........ ....... -. ......... ...... ...... ...... ...... ...... ...... ............ .................. ...... .... N W ... '" en ..., 00 '" .... .... ... .... .... .... .... .... .... .... N N N N N N N N N N W W a .... N W ... '" en ..., 00 '" a .... N W ... '" en ..., 00 '" a ..... Date/Time I Figure 12 January 2010 Hydrograph for King County Gauge 37G (148th Bridge) I I I I I I I I King County 18 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 4.868 3/30 313.54' 40 cfs 313.60 +0.06 4.612 3/30 313.97' 48 cfs 313.47 -0.50 4.455 3/30 312.04' 48 cfs 311.89 -0.15 'Elevation is based on tape down from top of footbridge. King County 17 December 2010 I I I I I I I •• I I I I I I I I ~--------------___________________ .. ________________ , .. __________ u. ____________________ ...... I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Survey data for the January 8 event were transposed to the nearest cross-sections (RM 4.8612 and 4.8285) just downstream of Parcel #0223059005 footbridge and the January 22 survey work was taken upstream of the Parcel #0223059005 footbridge (see Figure 11 and Table 6 below for more detail). Figure 11 Edge of water survey shown in light blue lines. Table 6 Water surface observations, elevations in NAVD88. Station Date Left Bank Right Bank Avg. 4.992552 1/22 314.27 313.85 314.06 4.988154 1/22 314.20 314.20 4.9749 1/22 314.35 314.04 314.20 4.949 1/22 314.08' . 314.14 314.11 4.937 1/22 314.17 314.14 314.16 King County 16 37G Flow Rate WS Profiles Diff. 13 cfs 313.00 -1.06 13 cfs 312.99 -1.21 13 cfs 312.98 -1.22 13 cfs 312.94 -1.17 13 cfs 312.91 -1.25 December 2010 700 600 500 :i 400 ~ ~ • £. 300 200 100 o Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project ~37a·obs ..... 37b-sim ..... Lower ..... Upper -+-37b-obs 1/4/2009 1151'2009 1/612009 11712009 118/2009 119/2009 1/1012009 1/11/2009 1f12/2009 TIme (Dally) Figure 10 January 2009 Hydrograph of event It is worth noting that although it was discussed previously about the faster response for drainages below 378, no effort was made on a storm event basis to match up peaks that might have shifts within the same day; which is similar to the method previously done by the sediment study. , One other comparison was performed using the HEC-RAS model developed for this project. At the May2 station, it was noted in the May Creek Sediment Transport Study, that the model was estimating approximately I-ft higherthan observed after calibration. This was based on the flow rate of 340+ cfs for those two storm events. An attempt was made to reconcile where the monitoring stations were in the HEC-RAS model and known stations and locations in the ravine. Stationing between the HEC-RAS model and assumed known locations of the gauging did not reconcile; thus, matching up where the documented elevations are at the study sites and cross- sections in the model was not possible at this time. 2.4.4 Model Validation Edge of water was surveyed on two different days, January 8, 2010 and January 22,2010. The January 8 survey was preceded by a small storm on January 5 cresting at 42 cfs as estimated at 14S th Ave SE bridge (KC Gauge 37G). Flows computed from the gauge during the survey on January 8 were approximately 29 cfs. The second survey occurred after a larger storm that began to recede January 16. The peak flow rate using the same stream flow gauge for that event was estimated to be 66 cfs. During the January 22 survey of edge of water, flows were estimated to have receded to a flow rate of 13 cfs as measured at KC gauge 37G (see Figure 12). King County 15 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project matches the critical shear stress presented in the sediment transport study based on observed data. Additionally, performing the same analysis but not including data after January 13,2006," the flow estimates at 378 are estimated to be 240 cfs and 280 cfs (rounding to the nearest 10 cfs) for the 2007 and 2009 events. These are based on linear extrapolation of the LOWESS regression results since the magnitude of the peaks for the 2007 and 2009 events did not exist in the reduced dataset. Comparing the simulated flow rates using the robust regression to observed at gauging station 378, there are good correlations, r-square's, and slope's when using all data greater than 100 cfs and for data greater than 100 cfs but excluding gauge records after January 13,2006 (Table 5). A perfect fit would have a coefficient of 1.0 for each of those statistics and an intercept of 0.0. As such, the robust regression slightly under predicts observed. Table 5 Accuracy of robust regression for simulated versus observed for gauging station 378 using linear regression statistics, with observed on the x-axis for slope. Intercept Dataset Pearson r·square Slope All Data greater than 100 ets 0.87 0.75 0.91 Greater than 100 cfs and exdudes data after 1/13/2006 0.88 0.78 0.82 700 "r---------------------------------------------------, 600----- 500 ._---"- 200 ------ -------- 100 ----- ----~--- o~ __ _e~ __________ ~ (ets) 10.1 14.8 ....... 37a·obs ~37b-slm -C -lower -0 -Upper ~37b-obs 1112912007 11/3012007 1211/2007 121212007 121312007 121412007 121512007 121612007 12fl12007 Time (Dally) Figure 9 December 2007 Hydrograph of event King County 14 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project In lieu of investigating Anchor's approach on using a subset of data and estimate an independent peak flow for 37b, a moderately different method was perfonned but for preliminary review adequate for comparison to Anchor's approach. Peak daily flow rates (based on mean-hourly) were assembled from November I, 1998 through February 5,2009 to be similar to Anchor absolute start and end dates-Ten plus years of data were used, and any days with missing data . in either gauge were disregarded for this analysis. Then a robust regression (LOWESS) was perfonned on the entire set of peak daily data (subsequently, the same date ranges were used as in Anchor-the LOWESS results remained the same). In short, the LOWESS regression provides a sophisticated method for perfonning regressions applicable for linear and non-linear data making it not necessary to separate high and low stonn events (Helsel and Hirsch, 2002). In addition to estimating the most likely value for 37B, secondary regressions were perfonned on the positive and negative residuals of the primary regression to estimate a range of possible values based on the primary regression (Figure 8). LOWESS Regression plot f=0.25 300r----,r----,-----,-----,--c-------~ 250 200 '" " ! 150 '" 100 300 250 ~ 200 'iii ~ 150 >- 100 200 300 x-Values • 400 500 Simulated y-Values using LOWESS Regression Sequence Index (e.g. datenum) 600 X 10' • Observed -Regression Upper/Lower Jan 2009 • Observed -Simulated Lower Upper Figure 8 Robust Regression (LOWESS-Locally weighted scatter plot smoothing) on Daily Peak Flow Rates from 11/111998 through 2/5/2009_ X-axis = 37A, Y-axis = 37B. Lower graph is a simulation of 37B using the regression and observed with time on the x-axis, and now rate on the y-axis. Results from the regressions estimates peak daily flows at 37B to be 233-cfs (with a possible range of 198 cfs to 260 cfs) for December 2007 (Figure 9) and 272-cfs (with a possible range of 218 cfs to 310 cfs) for January 2009 (Figure 10). Notably, this revised estimate more closely King County 13 December 2010 I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project I I I 8 I I I I I o 1/612009 11612009 11712009 1(712009 11812009 1/812009 119/2009 1/912009 1/10/2009 1/10/2009 1/11/2009 0:00 12:00 0;00 12:00 . 0:00 12:00 0:00 12:00 0:00 12:00 0:00 I Figure 7 Stages for January 2009 event. Note the missing data for 37G. I I I I I I I I I King County 12 December 2010 ---------------------------~ Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project roo 600 ~ soo 400 , ,\ ~"'-~ -lr ~ --~ '. .- 300 200 100 = o 1/1/2009 0:00 113120090:00 1/5120090:00 1(7120090:00 119120090:00 1111120090:00 111312009 0:00 1f15120090:00 Figure 5 Flow rates for the January 2009 event 10r----------------------------------------------------------, 9~--------------~------------------------------------~ 8~----------~====~~----------------------~ 3~----------------------------------------------__1 2~----------------------------------------------__1 1~----------------------------------------------__1 o~----__ ----__________________ ----------__ ----__ -----J -37A --M.y2 379 -37G 37G --37A -378 -May2 --May3 121112007 121212007 121312007 121412007 12f512OO7 121612007 12f712oo7 121812007 1219/2007 12110/2007 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 Figure 6 Stages for December 2007 event. Note the obvious data errors in station 37G. King County II December 20 I 0 I I I I I 1 I I' I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Moreover, there is a considerable area of highly developed landscape draining to 37A below 378. This drainage area with relatively high amounts of impervious would respond to an event significantly faster than the upper May Valley basin. This is il.lustrated by overlaying the various hydrographs for the December event (Figure 4). Thus, even though the daily peak flow rates for the various stations do occlir within the same day, the peak event at 37 A used should be just below 500 cfs--rather than the near 600-cfs for that event. 700 "r------------------------------------------------, 600 --.---------------------"--- 500 ----------- 400 -----. ~ '-----------.-- ----- 300 ------.,---- 200 ------------ -- 100· --- ------- ~ o"~-=====~~~-L---__ -L----------____ ~ -37A -May2 379 -37G 1211120070:00 1212/20070:00 12/3120070:00 1214120070:00 1215120070:00 ·'2/6120070:00 1217120070:00 Figure 4 Flow rates for the December 2007 event Conversely, while the fast response of the lower drainage areas presents themselves in the January 2009 event (Figure 5), that local maximum is less than the daily maximum coincident with the other stations. Thus the daily peaks used for the January 2009 event should be near 600-cfs at 37a (as was previously used). While the citation for the basis of the censoring the multiple years of continuous stream gauge records for 37a and 37b is provided, two apparent actions were taken in pre-processing the data: I) data were split into high flow and low flow events, and 2) some periods of record were filtered for use. Given the survey results at monitoring station May2, there were minor changes in channel geometry between the beginning and the end ofthe sediment study. Therefore, the continuous water level measured at that station was assumed to remain consistent throughout the sediment study period with possibly small adjustments to the associated flow rates. Thus all else being equal, a greater depth at that location would coincide with greater flows-assuming no downstream conditions influence the gauge. Reviewing the stages at May2 (Figure 6 and Figure 7) for those two events, January 2009 was observed to have a stage approximately O.5-ft higher than the December 2007 event. Thus, it is assumed the flows during the January event were greater than the 2007 event. King County 10 December 2010 ------------------------------ Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.4.3 Refined Estimate of Stream Flow Events for Phase II Sediment Study During the sediment study time period, there were two significant storm events that occurred, December 2007 and January 2009. Recorded stream flows during those events were determined to be unreliable (see Phase II, May Creek Sediment Transport Study). Additional investigation into estimating the magnitude of those two events was instructional to better understanding the sediment mobilization that occurred during the two events. Flows at stations: 37 A, 37B, May2, and 37G were evaluated for the two defining storm events (December 2007, January 2009) used to estimate incipient motion, 37H was not installed until WY 2010. At stations Mayl and May3 no flow estimates were done, only stage was recorded (see Figure 3 for locations). Because it has been reported of active erosion/deposition influencing water levels at 37B, during the January 2009 event there is more uncertainty for flow estimates. Additionally, using a scaling method to synthesize records at 37B, Anchor estimated the peak flow rates for December 2007 and January 2009 to be very similar (339 and 348 cfs, respectively). However, upon further investigation the estimate used for the December 2007 event was based on a peak at 37 A not appropriate for transposition to monitoring station 37B. Figure 3 Gauge monitoring locations The peak flow for the December 2007 event at 37 A was near 600-cfs; however, that peak clearly occurs prior to the peaks measured upstream at the various continuous recording stations. King County 9 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project -';, SeaTac SeaTac Mo.nt.~ to37V to 37U March 1.252 1.197 April 1.270 1.150 May 1.555 1.378 June 1.311 1.283 July 1.785 1.438 August 1.187 1.163 September 1.462 1.272 October 1.352 1.158 November 1.178 1.069 December 1.112 ,1.064 2.4.2 FTABLES FT ABLES are user defined channel routing tables characterizing the relationship between stage, surface area, storage volumes, and flow rates. Four of these FT ABLEs were modified to reflect the hydraulics modeled using HEC-RAS. Using the multiple flow rate profiles defined in HEC- RAS ranging from mean annual flow rates to I OO-year flood frequencies, a series of cross- sections were used to define the transient storage HSPF utilizes for kinematic wave routing. For every cross-section in HEC-RAS the stage and wetted area can be highly distinct, thus an average was developed for each of the four catchments in HSPF. The groupings of cross- sections per catchment are listed below: • RM 3.5 though 4.451 were used for HSPF catchment CCP-FTABLE 100 • RM 4.53 through 5.49 were used for HSPF catchment MVL-FTALBE 80 • RM 5.69 through 5.86 were used for HSPF catchment MVM-FTABLE 70 • RM 5.87 through 6.84 were used for HSPF catchment CFD-FTABLE 60. The depth and flow rates are weighted averages using the downstream channel length defined in HEC-RAS. Surface areas and storage volumes are summed up for each group of cross-sections defined above. While the overall differences are minor, this was performed for each geometric scenario and inserted into the HSPF scenarios for durational analyses. King County 8 December 2010 ,----------------------------------------------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 250 0.050 0.036 0.050 300 0.050 0.035 0.050 350. 0.050 0.034 0.050 2.4 Hydrology A numerical hydrologic model (HSPF) developed for the 1995 May Creek Current and Future Conditions Report was used to simulate the hydrologic regime for a 60 year period. To generate this long period of record, the National Weather Service Sea-Tac metrological station was used for precipitation, and the Washington State University Puyallup station was used for evapotranspiration (ET). The period of record simulated was from water year 1949 through water year 2008 (10/1/1948 -9/30/2008). 2.4.1 Precipitation Precipitation is processed to hourly intervals, while the ET is processed to daily increments. However in the lower Puget sound basin, the Cascade foothills topography create an orographic effect of increasing precipitation the further east and closer to the mountain range. As a result, the observations made at Sea-Tac station needs to be translated to the May Valley basin. There are any number of WllYS of doing this, one typical way is to scale precipitation using mean annual ratios of Sea-Tac to any local data in the basin. In general, this will provide a means for representing annual runoff volumes, but the scalar can be greatly divergent for a given season (e.g. over estimate storms in the winter and under estimate in the summer). This technique was used in the original Conditions report model. However, for this project a slightly more sophisticated technique was used to better preserve the Individual seasons (i.e. by month). In May Valley, there were two local precipitation stations used to scale the Sea-Tac data (King County station 37u for the lower parts of the valley, and 37v for the upper elevations of the valley. The Sea-Tac data were then scaled on a monthly basis using linear regressions with a constant of 0.0 for ea'ch month, such that zero precipitation at SeaTac will be zero precipitation in May Valley. This allows for closer approximation of seasonal variability. Thus, in the HSPF model where one would use a scalar to adjust the Sea-Tac precipitation, the scalar is kept at 1.0 since the scaling was done prior to the model run. Monthly Scalars are listed in the table below. Table 4 Monthly scalars to transpose SeaTac precipitation to May Valley. January 1.172 1.044 February 1.150 1.096 King County 7 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 7.605 4.6 7.05 10 6.943 8.4 5.278 8.6 4.388 13.6 2.3.3 Channel Roughness Defined channel roughness followed previous modeling efforts developed by Otak. Essentially, channel reaches with substantial reed canary grass or collections of willow tree root systems were simulated with a channel roughness decreasing with increasing flow rates (Table 3). Otherwise, channel roughness in continuously choked reaches has a constant channel roughness of 0.07 and where channel was assumed clear, a roughness of 0.04. In addition to channel roughness, obstructions were used represent effective blockages either from dense clusters of willow trees, or heavy mats of canary reed grass on the banks. Table 3 Vertical varying roughness by now rate 5 0.080 0.089 0.080 10 0.070 0.081 0.070 25 0.065 0.060 0.065 50 0.065 0.051 0.065 75 0.055 0.047 0.055 100 0.055 0.045 0.055 125 0.055 0.042 0.055 150 0.050 0.040 0.050 175 0.050 0.039 0.050 200 0.050 0.037 0.050 King County 6 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 5,87 Bridge-164th Avenue SE 5,04 Footbridge-Upstream of Parcel #323059038 4,868 Footbridge-Parcel #323059038 4,612 Footbridge-McFarland's 4.455 Bridge-148th Avenue SE 4,28 Bridge-146th Avenue SE 4,265 Weir-Partial rock weir 4,114 Bridge-143rd Avenue SE 2.3.2 Flow Rate Change Locations In a stream system where tributaries occur or where attenuations from in-channel and overbank storage volumes reduce peak flow rates, a defined water surface profile may have changing flow rates associated to a set of cross-sections in the modeL These flow rate changing locations in the hydraulic model were derived from two methods; either using observed gauge flows or results from continuous hydrologic model (HSPF), Statistical type flows such as mean annual, or 2 yr, etc" are based on outputs ofthe HSPF model, while any specific flow rate events evaluated were based on gauge data, In the hydraulic model, there were five defined inflow points starting near the headwaters as the upstream inflow down to where two lateral tributaries drain into the wetland on Open Space 803540, west of l48 th Ave SE, River mile stations for the flow,change locations defined in the model are: • River mile: 7,605 (defined as catchment outlet NFK), head waters of May Creek • River mile: 7,05 (defined as aggregation of catchment outlets: NFK, EFK, and LKC), confluence of North Fork, East Fork, and Lake Kathleen, at SR-900 • River mile: 6,943 (defined as catchment outlet MVM), local drainages feeding to downstream of I 64 th Ave SE • River mile: 5.277 (defined as catchment outlet MVL), drainages leading to I 48 th Ave SE • River mile: 4388 (defined as catchment outlet CCP), drainages leading to Coal Creek Parkway, As an example, the mean annual water surface profile is defined using the stationing from above, Flow rates start at the headwaters with 4,6 cfs, and accumulate to \3,6 cfs entering into the ravine, Table 2 Example of Flow Change Locations in HEC-RAS for mean annual now rate Station mean annual King County 5 December 2010 I I I I I I I I I I I I I I I I I I I -------------------------------------------------------~ I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.3.1 Survey Data King County recently surveyed much of the lower valley starting at Parcel #0323059038 property (approximately 950 ft downstream of 148 th ), to approximately 640 ft upstream of Parcel #0223059005 lower footbridge-approximately 3800 ft of stream length, during the month of January 2010. This surveyed area coincides with river miles: 4.266 through 4.99 (Figure 2). To further extend the model cross-sections from valley wall to valley wall, ground elevations using LiDAR data were used. Given the comprehensive extent of the field survey work, the addition of LiDAR was more for visualization rather than included in any of the hydraulic computations. The one exemption in the recent survey data were any bridge geometries upstream of 14S'h street (including 14S'h Street bridge). For these structures, existing geometry in the HEC-RAS model was used (see Table I for longitudinal stationing). o Ct>.I'.bt. Surln", 2O'OSUMly .... -~P'" -XSOJ1Un .. Footbridge: Parcel # 0323059038 Figure 2 Extent of January 2010 King County Survey Table I Stationing for structures in the HEC-RAS model Station Description 7.07 Bridge-May Valley Road 6.95 Bridge-Renton-Issaquah Road King County 4 December 20 IO Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.0. MODEL SYSTEM DESIGN Model design was dependant on available information and intended goals. of the project. Modeling of the May Creek system included a hydrologic (HSPF) and hydraulic model (HEC- RAS). The hydrologic model used was developed for the May Creek Current and Future Conditions report (King County 1995), while the HEC-RAS model was based on multiple modifications over time (King County 1995, Entranco 2002, Otak 2006) as projects occurred, with the most recent modifications performed by Otak in 2006. 2.1 Objectives The model system setup was designed to address May Creek Capital Improvement Project restoring hydraulic capacity with these objectives: I. assess channel capacity for existing and proposed designs, 2. assess changes in flood frequencies and durations, 3. assess channel competency to mobilize fines in May Creek through the valley, and 4. assess impacts to erosivity in the ravine downstream of 14Sth Ave SE. 2.2 System Overview In order to evaluate the stochastic nature of stream hydrology, it was necessary to perform a deterministic evaluation of the flow rates in the ravine and valley. Using the backwater computational abilities of HEC-RAS, channel routing tables (FT ABLES) were created to provide a detailed characteristic of reaches in May Creek in HSPF. Then using HSPF, hourly continuous stream flow data are simulated through the May valley and ravine. By simulating continuous hydrologic conditions for multiple decades (i.e. 60 years), the sequencing and permutations of selecting shapes and magnitudes of storm events are not needed. This framework then allows for a comprehensive durational analysis of exceedances of flow rates that inundate the valley and exceedances of flows above the incipient motion threshold in the ravine. 2.3 HEC·RAS Model Setup An existing model was used as a starting point for updating existing channel geometry with recent survey data collected in January 2010. Outside of the surveyed area, existing model definitions were used. Additionally, there was the intent to use the same stationing for location of cross-sections as was previously defined in the model within the surveyed area with cross- sections added where recent survey data suggested a change in topography that may not have been present in the previous modeling efforts. This included a denser set of cross-section stationing to better encapsulate undulations of the stream profile where adverse slopes between segments were common or where vegetation choke points are occurring .. The existing model domain started a short distance downstream of Coal Creek Parkway, to two- thirds ofa mile upstream of where May Creek crosses May Valley Road at S.R. 900 (a little over 4 miles in total). King County 3 December 2010 I I .' I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I '20 10 SWv.,.,,, -XSQI1Unoo 0"""" --s ...... Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure I Locator map of study area in May Creek basin. King County 2 December 2010 Hydraulic and Hydrologic Analyses of the May Creek 'Channel Restoration Project 1.0. INTRODUCTION May Creek valley experiences out of bank flooding on a routine basis every wet season lasting from several days to weeks at a time, The stream course is essentially in a bowl for approximately 2100 feet (river mile 4.6 to 5,0) between a footbridge upstream of Parcel #0223059005 property down to Long Marsh confluence-just upstream of another footbridge. Long Marsh is primarily a forested basin with steep gradients. This characteristic gives the tributary the ability to deposit gravels large enough that May Creek is not capable to redistribute gravels downstream. Thus stream bed elevations at this location rise as more gravels are deposited. This accumulation then backwaters May Creek upstream causing more deposition of fines and decaying vegetation-ultimately reducing conveyance capacity and increasing frequency of valley flooding. Like any natural stream system, larger but less frequent flow rates perform work on the stream banks and bed, Downstream of the valley, May Creek drops into a ravine where channel forming processes are expected. A recent sediment transport study was conducted at three' locations in the ravine between Coal Creek Parkway and 148 th Ave SE (King County 2009) characterizing conditions capable of causing erosion in the ravine. Those results are used to evaluate effects of this proposed study, 1.1 ,Study Goals The goal of this study is to evaluate channel capacity for different alternatives in the valley area to maintain flow rates near I-year flood return interval by showing a reduction in frequency and duration of flooding. The reduction in duration of flooding is intended to affect only the most frequent, smaller storms, therefore unlikely to have any significant impact to the larger storms capable of eroding downstream conditions. Additionally, the proposed conveyance improvement should also be sustainable by passing through silts and retarding buildup of fines. In order to perform these types of analyses, a combination of techniques was necessary to evaluate detailed hydraulics and hydrology. Two types of models were used to perform the analyses, HEC-RAS for hydraulics and HSPF (Bicknell 2005) for hydrology. Both models used were adapted from existing models and updated to reflect current conditions. HEC-RAS (VSACE 2005) was used to evaluate channel conveyance capacities and flooding inundations, while HSPF was used to provide statistical measures of durations and magnitudes of storm events. 1.2 Study Extent While the extent of the proposed channel improvements extend from river mile 4.31 up to river mile 4.99 (yellow highlight in Figure I), it was necessary to extend the boundary conditions to support the ravine erosion analysis and include the lower portions of the HEC-RAS hydraulic model down to the Coal Creek Parkway, river mile 3.59 (model extent shown as cross-sections in green in Figure I). Similarly, the watershed model used encompasses the entire basin as shown in light red in Figure I. King County 1 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project flow hydraulics frees up overbank storage for larger stonns, such that results of this study estimate that stonn events greater than the 10-year will either remain the same or marginally reduce in peaks. Stonn events between the I-year (approximately 10% increase) and the 10-year (approximately 1% increase) slightly increase, with all estimated increases or decreases calculated within model accuracy of a calibrated hydrologic model. Durations of flows near the 2-year (i.e. 200 cfs) and above are essentially the same. Durations of flows at 100 cfs again are nearly the same with an estimated difference in durations of approximately 400 hours over a 60 year period (525,960 hours, 0.08%). The higher the flow rates the less difference in durations to be expected. Sediment mobility was also evaluated to estimate expected lifespan of the project. Channel bottom sediments in the project area are comprised mostly of silty fines and organic muck. With this type of channel bottom, it's estimated that a shear stress of 0.01 pounds per square foot is required to move sediment downstream. A mean annual flow rate (i.e. 9 cfs) was selected to evaluate success of the project given that flows at or above the mean annual level occur during most of the year, thus minimizing the possibility of any significant recruitment of fines or vegetation re-establishing in the channel. Post project, estimates of shear stress at 9 cfs are at or above 0.0 I psf except downstream of 148 th Ave SE in the wetland. There at low flows, deposition is expected to occur similar to existing conditions. These results signify that given the management of gravel deposition from Long Marsh Creek and ability to mobilize fines in May Creek, post project conditions should continue into the future with minimal deposition of fines reducing intended channel capacity. Based on the sediment transport study conducted downstream in the ravine (King County 2009), channel sediment mobilizes approximately at 233 cfs (refined from original flow rate estimates of275 cfs). This estimate along with marginal changes in durations of flows (maximum difference at 100 cfs with 0.08%), suggest no significant downstream impacts in the ravine resulting from proposed project designs. It is acknowledged that there is a level of uncertainty in estimates of stream channel sediment mobilization thresholds that could be lower. Given the maximum estimated difference in durations (at 100 cfs) is approximated to an annual average increase of 7 hours during the course of a year; these effects would likely be undetectable in the ravine. King County vii December 2010 ,-------------------------------------------------------- Hydraulic and Hydrologic Analyses otthe May Creek Channel Restoration Project EXECUTIVE SUMMARY May Creek in May Valley routinely flows out of channel inundating adjacent pastures and wetlands during the wet season. At the downstream end ofthe valley, the natural landscape constrains stream flows back into channel controlling flow rates leaving the valley before entering the ravine. This feature, coupled with the flat pasture lands, are reasons why flooded areas in the valley can take several days to sufficiently drain; returning to usable pasture lands. Combine this with a frequent occurrence of small storms and portions of the pasture lands expectedly remain unusable for much of the wet season with frequent undesirable inundation continuing through spring and into the summer months. Given these conditions, the proposed project focuses on areas upstream leaving the natural constricting features unaltered. A study was conducted for May Creek in May Valley to evaluate stream channel capacity for existing and proposed conditions. This report contains hydrologic and hydraulic analyses (H&H) used to help optimize project design. Analyses include: assessment of channel capacity . for existing and proposed designs, assessment of flood frequencies and durations, assessment of channel competency to mobilize fine sediments and improve lifespan of the project, and assessment of impacts to erosivity in the ravine downstream of 148'h Ave SE. Two types of models were used, HSPF and HEC-RAS. HSPF is an U.S. EPA hydrologic watershed model used extensively in the Puget Sound region. The original model used was developed for the May Creek Current and Future Conditions report (King County 1995). This model was updated with more current meteorology and channel routing to improve understanding of stream responses with longer periods of precipitation record and more accurate hydraulics. The HEC-RAS model used was last modified by Otak in 2006. For this study, new land survey work was completed in 2010 to update channel geometry and enhance resolution specific to this project study area, supporting simulation of several proposed channel restoration activities to reduce frequency of flooding without significant downstream impacts. At the lowest point in channel capacity under existing conditions, it is estimated that May creek begins to flow overbank at approximately 6 cubic feet per second (cfs). This flow rate is below the estimated mean annual flow rate of 9 cfs. Thus for most of the wet months, small portions of the pasture susceptible to these minor exceedences will remain inundated. Additionally, a tributary (Long Marsh Creek) historically deposits large gravels from a mostly forested subbasin in May Creek just upstream Ofa footbridge (approximately at river mile 4.6). These gravel deposits are large enough to backwater May Creek upstream for a couple thousand feet. This backwater condition facilitates the recruitment of more fines and vegetation litter that decays into organic muck. This muck then allows for an increase of vegetation encroachment of the channel further reducing channel capacity. The project study proposes an excavation of the channel between 148'h Ave SE and approximately 2000 feet upstream to an elevation of 308 ft (NA VO 88). Additionally, dense vegetation choke points downstream of 148'h Ave SE will be thinned to reduce impediment of low flows exiting the valley heading to the ravine. Hydraulic analyses estimate that post project channel capacity will be increased from 6 cfs to approximately 50 cfs before overbank flows begin. This improvement will effectively reduce most small storms from flooding the pasture areas. However, this channel improvement is still below the magnitude of an annual storm, thus May Valley is still expected to flood annually, but with shorter duration. This change in low King County vi December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table 2 Example of Flow Change Locations in HEC-RAS for mean annual flow rate ................. 5 Table 3 Vertical varying roughness by flow rate ....................................................................... : .... 6 Table 4 Monthly scalars to transpose SeaTac precipitation to May Valley ................................... 7 Table 5 Accuracy of robust regression for simulated versus observed for gauging station 378 using linear regression statistics, with observed on the x-axis for slope .............................. 14 Table 6 Water surface observations, elevations in NAVDSS ....................................................... 16 Table 7 Summary of flood frequencies for Scenario I and Scenario S for May Creek in the valley ..................................................................................................................................... 47 Table S Summary of flood frequencies for Scenario I and Scenario S for May Creek in the ravine ..................................................................................................................................... 47 Table 9 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows passing through the project area (catchment MVL outlet at 14Sth Avenue SE) based on HSPF simulation WY 1949 -WY 200S .......................................................................... 53 Table 10 HEC-RAS calculated shear stress in channel for Scenario S, mean animal equals S.6 cfs. Zero shear stresses are highlighted in tan color ............................................................ 55 Table II Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows in the ravine (catchment CCP) based on HSPF simulation WY 1949 -WY 200S (525,960 hours) ..................................................................................................................... 56 King County v December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure 24 Water surface profiles for the I-year (Conditions Report) for Scenario I and 8. Red circle highlights the convergence of profiles at 146th Ave bridge ........... , ........................... 32 Figure 25 Water surface profiles at 50 cfs for Scenario I and Scenario 8 .................................... 33 Figure 26 Water surface profiles for the 100 year flood event for Scenario I and 8 .................... 34 Figure 27 Water surface elevations (Scenario I and 8) for the 100 year (Conditions Report) at the I 46th Ave bridge ................................................................................................................... 35 Figure 28 Water surface elevations for the 100 year retumperiod (Current Conditions) at bridge crqssing at 143rd Avenue SE for Scenario I and 8 .................................................... : ......... 36. Figure 29 Perspective plot for Scenario I (Existing Conditions) mean annual flow rate (8.6 cfs at 148th Street) .......................................................................................................................... 37 Figure 30 Longitudinal plot for Scenario I (Existing Conditions) water surface profile for mean annual flow rate ..................................................................................................................... 38 Figure 31 Perspective plot for Scenario I and 7 (vegetation removal) 50 cfs at 148th Street. Light blue are for existing conditions while dark blue are for Scenario 7 ... : ........................ 39 Figure 32 Water surface profile at 50 cfs for Scenario I and 7 .................................................... 40 Figure 33 Perspective plot comparing Scenario I and 7 under mean annual flow rates .............. 41 Figure 34 Perspective plot for Scenario I and 8 overbank flooding with 50 cfs at 148th Street. Light blue areas are inundated areas for Scenario I and dark blue are Scenario 8 ............... 42 Figure 35 Water surface profile at 50 cfs for Scenario I and 8 ................................................... , 43 Figure 36 Water surface elevations for the 2 year return period (229 and 240 cfs) for Scenario I and 8 ...................................................................................................................................... 44 Figure 37 Perspective plot for Scenario I and 9 overbank flooding with 50 cfs at 148th Street. Dark blue areas are for Scenario 9, light blue are for Scenario I (existing conditions) ....... 45 Figure 38 Water surface profile at 50 cfs for Scenario I and 9 .................................................... 46 Figure 39 Flow Frequencies for existing conditions using USGS 17-8 methodology for flows at I 48th Avenue SE (catchment MVL) .................................................................................... 49 Figure 40 Flow Frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) for flows drainging to 148th A veneue SE. ....................................................... 50 Figure 41 Flow Frequencies using USGS 17-8 methodology for existing conditions at Coal Creek Parkway (catchment CCP) ......................................................................................... 51 Figure 42 Flow frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) at Coal Creek Parkway (catchment CCP) ........................................................ 52 Tables Table I Stationing for structures in the HEC-RAS model... .................................... :; ..................... 4 King County iv December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure I Locator map of study area in May Creek basin ................................................................ 2 Figure 2 Extent of January 20 I 0 King County Survey ................................................................... 4 Figure 3 Gauge monitoring locations ............................................................................................. 9 Figure 4 Flow rates for the December 2007 event.. ...................................................................... 10 Figure 5 Flow rates for the January 2009 event.. .......................................................................... II Figure 6 Stages for December 2007 event. Note the obvious data errors in station 37G ............. II Figure 7 Stages for January 2009 event. Note the missing data for 37G ..................................... 12 Figure 8 Robust Regression (LOWESS-Locally weighted scatter plot smoothing) on Daily Peak Flow Rates from 111111998 through 2/5/2009. X-axis = 37A, Y-axis = 378. Lower graph is a simulation of 37B using the regression and observed with time on the x -axis, and flow rate on the y-axis ................................................................................................................... 13 Figure 9 December 2007 Hydrograph of event ............................................................................ 14 Figure 10 January 2009 Hydrograph of event .............................................................................. 15 Figure II Edge of water survey shown in light blue lines ............................................................ 16 Figure 12 January 2010 Hydrograph for King County Gauge 37G (148th Bridge) ..................... 18 Figure 13 Profile of observed water surface elevations for January 8 (downstream of footbridge) & 22 (upstream offootbridge) with left and right bank elevations (LOB, ROB) plotted .... 19 Figure 14 Example of cross-section where water surface elevation is same elevation as bank elevation (RM 4.974). Obstruction in cross-section is representative of dense canary reed grass on the banks ................................................................................................................. 20 Figure 15 Example of overbank flooding slowly draining back into channel after a storm from 7 days prior (with some minor precipitation 4 days prior). Photo taken 3/19/2010 ............... 21 Figure 16 Observed water surface elevation for January 14, 2010 at 64 cfs at Parcel #0223059005 footbridge ....................................................................................................... 22 Figure 17 Observed water surface elevation for March 30, 2010 at 48 cfs at three bridges ........ 23 Figure 18 Scenario 7 longitudinal profile in study area. The black line is channel bottom using top of sediment (used in Scenario I) and fuschia color line is profile of channel bottom to firm sediment. ....................................................................................................................... 26 Figure 19 Scenario 8 showing existing conditions and proposed profile after sediment removal (308 ft) and flushing of silts .................................................................................................. 27 Figure 20 Scenario 9 showing existing conditions and proposed profile after sediment removal (309 ft) and flushing of silts .................................................................................................. 28 Figure 21 Typical Channel Geometry of existing (black line) and proposed (fuschia line) ......... 29 Figure 22 Guo-Shields Empirical Curve ....................................................................................... 30 . Figure 23 Scenario I (existing conditions) water surface profile for mean annual (filled in water surface) and Conditions Report I year event (blue line with symbols) ................................ 31 King County December 2010 -------------------------_ .. _------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table of Contents Executive Summary ....................................................................................................................... vi 1.0. Introduction ......................................................................................................................... I 1.1 Study Goals ..................................................................................................................... I 1.2 Study Extent ............................................................... , .................................................... I 2.0. Model System Design ......................................................................................................... 3 2.1 Objectives ....................................................................................................................... 3 2.2 System Overview ...................................................................................... : ..................... 3 2.3 HEC-RAS Model Setup ...................................... : ........................................................... 3 2.3.1 Survey Data ................................................................................................................. 4 2.3.2 Flow Rate Change Locations ...................................................................................... 5 2.3.3 Channel Roughness ..................................................................................................... 6 2.4 Hydrology ....................................................................................................................... 7 2.4.1 Precipitation ................................................................................................................ 7 2.4.2 FTABLES ................................................................................................................... 8 2.4.3 Refined Estimate of Stream Flow Events for Phase II Sediment Study ..................... 9 2.4.4 Model Validation ...................................................................................................... 15 3.0. Scenario Development ...................................................................................................... 25 3.1.1 Model Geometry ....................................................................................................... 25 3.1.2 Typical Channel Cross-Section ................................................................................. 28 4.0. Sediment Transport ........................................................................................................... 30 5.0. . Results ............................................................................................................................... 31 5.1 Improved Channel Conveyance .................................................................................... 37 5.2 Updated Flow Frequencies ........................................................................................... 46 5.3 Reduced Duration of Flood Inundation for Smaller more Frequent Events ................. 52 5.4 Flow Rates Competent to Pass Silts through the System ...................................... ; ...... 54 5.5 Durations of Flow Rates in the Ravine ......................................................................... 56 5.6 Other Considerations .................................................................................................... 57 6.0. References ......................................................................................................................... 58 Figures King County ii December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Citation King County. 2010. Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks, Science Section. Prepared for Stormwater Services Section, Capital Services Unit. King County December 2010 ------------ - ------------------------------------------ Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Prepared for: King County Department of Natural Resources and Parks Stormwater Services Section, Capital Services Unit Prepared by: Jeff Burkey Hydrologist King County Water and Land Resources Division Department of Natural Resources and Parks ti King County Department of Natural Resources and Parks Water and Land Resources Division (206) 296-6519 I I I I I I I I I I I I I I I I I I I I I I II I I I I I I I I I I I I I I I I EXHIBIT 26 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project December 17, 2010 King County Department of Natural Resources and Parks Water and Ulnd Resources Oivlslon Science Section King Street Center. KSC-NR-0600 201 South Jackson Street. Suite 600 Seattle. WA 98104 Alternate Formats Available 206-296-7380 TTY Relay: 711 Cit\' of Renton °n90IVISIOn Plannl --------------~- EXIS11NG TOPOGRAPHIC AND PHYSICAL SHOWN ON 'THIS PLAN ARE FROM TO SITE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) WRN EAST ON S.E. MAY VALLEY ROAD. GO TO 148'TH AVE S.E.. WRN TO BRIDGE OVER MAY CREEK. N.A. ON THIS SHEET 11TLE: CREEK DRAINAGE I 11TLE: "r,""" MAP H: 1" -2000' I A<:<I<:TA"o.. BY: LINDSEY MILLER MEREDI'TH RADELLA ---~-------- o 1 W King County WORK: FLOW OBSTRUC11NG VEGETA110N AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NA 11VE VEGET A l10N ON BO'TH SIDES OF CHANNEL. ENHANCE OFF-CHANNEL I\£TLAND FISH HABITAT DOWNSTREAM OF 148'TH S.E. SHEET: 1 OF 8 DATE: AUG 13, 2010 i :1 pESIGN L fGEND W?A'?W7Aa SEDIMENT REMOVAL AREA ~ .. /' . MITIGATION WORK AREA ~ WITH ALCOVES ~ ... --. --WETlAND BUFFER (11 0') .STREAM BUFFER (165') PLANTING MrTlGATION LINE (15' BUFFER) . EXISTING ~EGEND -.. -.. -.. -TOE (BOTTOM) OF STREAM --DRIVEWAY LINE ... FENCE SURVEY CONTROL ---PROPERTY LINES ------R-O-W LINES .v'..:·---''''----OELINEATED WETLAND THE EXISTING TOPOGRAPHIC AND PHYSICAL TURES SHOWN ON THIS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVATIONS AND LAND SURVEY . I SITE: FROM CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AVE S.E .. TURN SOUTH TO BRIDGE OVER MAY CREEK. WASHING STATE LAMBERT GRID / 91; NAVD 88 \ ~_--l_ o 200 SCALE IN FEET 0+00 -15+00 1" = 200' ",""<~r"'rF BY: LINDSEY MIUER MEREDITH RADELIlA tQ King County REMOVE FLOW OBSTRUCTING VEGETATION AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NATIVE VEGETA110N ON BOTH SIDES OF CHANNEL ENHANCE OFF-CHANNEL WETLAND FISH HABITAT DOWNSTREAM OF 148TH 5.E. SHEET: 2 OF 8 DATE: AUG 13, 2010 ,----------------------------------------------------------------------- " \ .. ~, TO SITE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD. GO TO HBTH AVE S.E .. TURN TO BRIDGE OVER MAY CREEK. TUM: WASHING STATE LAMBERT GRID /91; NAVO BB -~20;:::0:----:!O 200 SCALE IN FEET MAY CREEK DRAINAGE 15+00 -29+00 1" = 200' I ASSls~r ANCE BY: UNOSEY MILLER MEREDITH RADElLA \ \ \ WORK: \ \ .\ \ w'\ W King County REMOVE FLOW OBSTRUCTING VEGETATION AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NATIVE VEGETATION ON BOTH SIDES OF CHANNEL ENHANCE OFF-CHANNEL WElLAND FISH HABITAT DO\\NSTREAM OF 148TH S.E. SHEET: 3 OF 8 DAlE: AUG 2010 , , , .315 .. 6, .! ... :Q(J$iiNq ~~ .. t ..• + .. _ ............ cc ....• .... J-. ......... - ElCIS,I1N.G .. SlEWlBED ..... \.3.1.5.0. ,: . .....•. ~., .... --..• : .. ~:... .... -.... -: ... ·_1 +~.o.~ ___ .". _+ i····· StO~E-BANKSJI3OlH-SiDEs-·TO· -+._, . .:. ... 1\ ... " SlU'LAR·-TO-EXlSTlNG;-lYPICAttY·-O:5··.. . ·-··T"-t:: .jj(io ! 'TO'1 ·H/'T. MAXIl.t"UIof S[()pE"1:S:"1" . t···:·· .:., "-. . '30~:o .•. !:.···· •.• · •.•..• ·\\-t.~ •.••. ···~s~J"~~;':"~ •• ~ ... ~ ... e:.-::~-:~:~,~:.!.~ .. ~ .. ~~~3~S~~:2~ .=35(0'0' . 3O':O'O'·"~~i()Q2l?:9O'.~·tN)()'tO':O'O'·· '5:~ci' TYPICAL SECTION: SEDIMENT REMOVAL .. ; .325.0' .. ' ... ;.320'.0' il~~~~~=1~~~EJ . :. ...\ ..... I .. _." __ .... . i :::'~~3f5:0 .i. .... ; .jjQ~O .. !. ; 3O'5~6DI ! .. 10',0'0- 1" = 10' ... t . TYPICAL SECTION: VEGETATION REMOVAL 1".= 10' URPDSE: REDUCE DURATION OF FLOODING PROJECT TITLE: DN PRDPERTIES ADJACENT TO MAY CREEK; MAY CREEK DRAINAGE'IMPRDVEMENT BETWEEN APPRDX. RIVER MILE 4.3 AND 4.9. IRECTlDNS TO SITE: SHEET TITLE: FRDM CDAL CREEK PARKWAY, (EAST DF SECTION VIEWS 1-405) TURN EAST ON S.E. MAY VAU,EY RDAD. GO TO 148TH AVE S.E .. TURN SDUTH TO BRIDGE OVER MAY CREEK. ATUM: AS STATEC SCALE: NDT TO' SCALE ASSISTANCE BY: LINDSEY MILLER DRAWN BY: MEREDITH RADEu.A . 5:C . ........ '. I .. i :3"o5:ty. ~ King County RO'PDSED WDRK: REMOVE FLOW DBSlRUCTlNG VEGETATlDN AND SEDIMENT FRDM MAY CREEK. PLANT 15' BUFFER DF NATIVE VEGETATION DN BOTH SIDES DF CHANNEL ENHANCr OFF-CHANNEL WETLAND FISH HABITAT DDWNSlREAM OF 14BTH A S.E. SHEET: 4 OF B DATE: AUG 13, 20'10' . ALCOVE( l' ABOVE' I . . . : : : . : . : . : I ~~~~.: .... : .... " ... ; .... :. .. .... .... .... .. ...... " .. "GRAO£' AiCOl/E . 5' s:d Wi) . Iii 'OOCH" ... :.... .... .... .... ... Ie (EL; : EXISTING GROUND APPRoX, :10S! . : I 'lYPICAI;' : . '" . ... :..: FI«Jt.1;LOW POlNT OF' ¢HAll!NEl: '.. .... ~E'<E!~)IL';: ':~~~ .. ~.:. H ~~ •• ':::.::~::.::: ::::~::':;,'::,::: ':;:0:: ::::i~;~;:' ;': .. ::.: :':.;: ;·.l<Y::. " ... ".dNsrALL. STREAuBED . .GRAVEi. 6~ .DEEP..IiY .. l5: .. Y.iDE.(JNLANo): .... : .. " .... : ..... . AT ALCOVE :;rATIONS. : ::: : . : : . . : ... SEE .GRAVEL .srEClFlcArIONs. rillS. SHEEr . ...:.. . :. .:...:. : HABITAT MITIGATION ALCOVE GRADING 1" = 20' OR COMBINATIONS THEREOF WILL BE USED TO REDUCE MDBIU'lY OF LWD: EMBEDMENT OF 50 PERCENT SURFACE AREA OF LOGS AND WILLOW ANCHOR POLES • TRENCH/BURY 60 PERCENT OF LOG LENGTH PINNING OF lOGS AND ROOTWADS BEHIND EXISTING TREES GREATER THAN 12" DIAAlETER IN COMBINATION WITH PARTIAL TRENCHING OF lOG HABITAT LOG MITIGATION PLACEMENT 1" = 50' SHm TITLE: SECilON VIEWS tQ King County REMOVE flOW OBSTRUCTING VEGETAilON AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NAilVE VEGETATION ON BOTH SIDES OF CHANNEL ENHANCE OFF-CHANNEL WETlLAND FISH HABITAT DOWNSTREAM OF 148TH S.E. SHEET: 5 OF B AUG ,2010 M mGATION PI AN NOTES (Al CON~TRUCnoN NOTES 1. TREES TO BE PRESERVED WILL BE FlAGGED IN THE FlELD BY rHE ECOUGIST. 2. INSTALL SILT FENCES WHERE DESIGNATED ON THE PLANS. INSTALL f>Ioff OTHER EROSION AND SEDIMENT CONTROL MEASURES AS REOUESTED BY THE ENGINEER 3. ELEVATION SHOWN ARE FlNAL GRADE, 4 TO 6 INCHES OF OVER-X WILL OCCUR AND BE BACKFlLLED FlLLED WITH STREAMBED GRAVELS OR COMPOST ON AREA 4. EXCAVATION ADJACENT TO THE STREAM CHANNEL SHALL TAKE PLACE ONLY DURING THE FISH WINDOWS AS DESIGNATED IN THE PERMITS. WHEN EXCAVATING ADJACENT THE STREAM CHANNEL AN EARTH PLUG SHALL BE LEFT BETWEEN THE EXISTING STREAM CHANNEL AND THE EXCAVATION AREA. PRIOR TO REMOVING THE EARTH PLUG AND CONNECTING THE EXCAVATED CHANNEL, A TURBIDrTY CURTAIN SHALL BE INSTALLED AS SHOWN IN THE DETAILS TO PROTECT THE STREAM FROM SEDIMENT AND TURBIDrTY DURING CONNECTION. S. IF ANY GROUNDWATER IS ENCOUNTERED DURING EXCAVATION, DEWATER BY PUMPING AND BROAOCASTINGTURBID WATER THROUGH SILT FENCE AND DISSIPATED OVER VEGETATED STRIP IN UPLAND AREAS OF THE SITE 6. ELEVATIONS ASSOClo'oTED WrTH CONTOURING ALCOVE AND FLOODPlAIN AREAS IS TO BE DIRECTED BY ECOLOGIST IN THE FlELD. 7. PARTIALLY BURY AND PLACE LOGS IN THE EXCAVATED ALCOVE, ·LOG PLACEMENT SHOWN IN THE PLANS ARE SCHEMATIC; ACTUAL PLACEMENT AND ARRANGEMENT TO BE DETERMINED BY THE ECOLOGIST IN THE FlELD. INSTALL 2" DIAMETER WILLOW AND COTTONWOOD ANCHORING POLES AS SHOWN IN THE PLAN DETAILS. 8. PLACE 6 INCHES OF STREAMBED GRAVELS WITHIN THE ALCOVE AREA. 9. PLACE LOGS IN THE FLOOPLAIN, LOG PLACEMENT SHOWN IN THE PLANS ARE SCHEMATIC; ACTUAL PLACEMENT AND ARRANGEMENT TO BE DETERMINED BY THE ECOLOGIST IN THE FIELD. INSTALL 2" Dlo'oMETER WILLOW AND COTTONWOOD ANCHORING POLES AS SHOWN IN THE PLAN DETAILS. 10. PLANT EMERGENTS AND ·SHRUBS ACCORDING TO PLANTING PLAN. 11. REMOVE TEMPORARY STABIUZED CONSTRUCTION ENTRANCES AND REMOVE HIGH-VlSIBILrTY FENCES, AND ANY OTHER EROSION CONTROL MEASURES STILL INSTALLED AT THE SmE. 12. CONTRACTOR SHALL PROVIDE STREAM ISOLATION / TURBIDrTY CURTAIN PER WASHINGTON DEPARTMENT OF ECOLOGY STANDARDS. SEE SHEET 7 FOR PLANTING NOTES. URPOSE: REDUCE DURATION OF FLOODING ON PROPERTIES ADJACENT TO MAY CREEK; BETWEEN APPROX. RIVER MILE 4.3 AND 4.9. DIRECTIONS TO SITE: FROM COAL CREEK PARKWAY, (EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AVE S.E., TURN SOUTH TO BRIDGE OVER MAY CREEK. pA TUM: AS STATED N ~ 7.olo--IQi .~ King County PROJECT TITLE: PROPOSED WORK: MAY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING SHEET TITLE: MITIGATION NOTES SCALE: NOT TO SCALE ASSISTANCE BY: UNDSEYMILLER DRAWN BY: MEREDITH RADELLA VEGETATION AND SEDIMENT FROM MAY CREEK. PLANT 1S' BUFFER OF NATIVE VEGETATION ON BOTH SIDES OF CHANNEL. ENHANCE OFF-CHANNEL WETLAND FISH HABITAT DOWNSTREAM OF 148TH AVI S.E. SHEET: 6 OF 8 DAlE: AUG 13. 2010 .------------------------------ MI]M]]Q~ e~N ~QIES CONTINUED (B) PLANTING NOTES 1. MrnGATION PLANTING PLANS REPRESENT A CONCEPTUAL PlANT LAYOUT. WILL BE DIRECTED IN THE FlELD BY THE ECOLOGIST. ALL MITIGATION PLANTING PREPARATION 2. PlANTING SHALL TAKE PLACE DURING THE DORMANT SEASON (NOVEMBER 1 ST THROUGH· FEBRUARY 28TH). PlANTING MAY BE ALLOWED AT OTHER TIMES AFTER REVIEW AND WRITTEN APPROVAL BY THE ECOLOGIST. 3. WITHIN THE FLOODPLAIN EXCAVATION AREAS AND ALL PLANTING .AREAS WHERE REED CANARYGRASS HAS BEEN COMPLETELY REMOVED, PRO~DE AND INSTALL 4 INCHES OF COMPOST (PER SPEC) ROTOTILLED TO A (12) INCH MINIMUM. 4. IN ALL PlANTING AREAS WHERE REED CANARYGRASS IS PRESENT, FlRST MOW THE GRASS. COVER MOWED REED CANARYGRASS WITH CARDBOARD (OR A SIMIlAR BARRIER MATERIAL AS APPROVED BY THE ECOLOGIST) FOLLOWED BY 6 INCHES OF COMPOST. 5. PlANT SHRUBS AND TREES THROUGH THE CARDBOARD AND COMPOST AS DIRECTED BY THE ECOLOGIST. 6. ALL PLANTS SHALL BE NURSERY GROWN A MINIMUM OF ONE YEAR. PLANT MATERIAL IS TO BE SUPPLIED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PlANTS NATIVE TO THE PACIFlC NORTHWEST. PlANT MATERIAL SUBSTITUTIONS ARE SUBJECT TO APPROVAL BY THE ECOLOGIST. 7. NO TACKIFER, HERBICIDE, OR FERTlUZER SHALL BE USED IN THE PlANTING AREAS. (C) GENERAL NOTES 1. TO PREVENT REESTABLlSHMNET OF INVASME VEGETATION, THE TOP 24 INCHES OF EXCAVATED SOIL IS NOT TO BE REUSED AS FlLL ANYWHERE ON THE PROJECT SITE • 2. . DO NOT DRME EQUIPMENT IN AREAS OF THE SITE WHERE COMPOST HAS BEEN MIXED INTO THE NATME SOIL. May Creek Riparian Buffer Planting, east of 148th Ave SE .......... Common Name SImISpeclflcaUons QuanUty T .... ~.-....... l"CtIipor@6-I'&; .... '" PIMl9'o.c. n.:..1iI<...w ........ UB,UHciIk< Fulo....,,,,,,,,, '" I'IIIIIVO.C 1qM1lJi~_ --I" Cdip<r@l_HapISboakSnipTnmk '''' -..,. PIUI,.o.c. -"" ... Woalemr«l ..... !WI,:5~ Hcistu hi! na... JIaIiop '" Plul VO.C Shrubs/Willows --J.af...c...-~ _ 24" KO",~ I r _ SpraoI Nmmum ~ """"') r;.._ ,. "..,vo.c P~cap~-... ille"""'" U" lIo!p~ n"Il ... ,Sj:I_MiRimum 4 ...... , Ji .... b""'f'IMI .. m '" ----U"Hc/aItt. IC" I.0oI SpnIIodMirlimllm4...,;p, 1 1Ioc_ m _vue. 1I ....... spu>tIbIIlJ ~-24""Ha.u, II" R_Sp-tMio ....... 4 lwiJr,3 u.._ = PIuIL6'o.c .... -.. """ .... a.;....-....~W'l.cIqlll-l·Diomaa- MitiaMua 6 IM_ -PbIoI4'ac. U..SIak ... ~l~Loocm-I"~ '""--SoouI .... .wiJkM MiIIimom 6 JioH IoIIb •• PIaaI~·o.c. Groundtovor iji l.~ftlIz-ftJrdOfl_ ...,~ 6" Ui;Iu, r....sI>llnbnwll..1tandI '00 --PlaaI4'o.c. .Ic<h ... ~ "-m tl' h;p, ".,.ad. JoollaiaD ....... ~ ~ ingCounty PbnI4'o.C. URPOSE: REDUCE DURATION OF FLOODING PROJECT TITLE: ROPOSEO WORK: ON PROPERTIES ADJACENT TO MAY CREEK: MAY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING BETWEEN APPROX. RIVER MILE 4.3. AND 4.9. VEGETATION AND SEDIMENT FROM PIRECTIONS TO SITE: SHEET TITLE: MAY CREEK. PLANT 15' BUFFER OF FROM COAL CREEK PARKWAY, (EAST OF PLANTING NOTES AND TABLE NATIVE VEGETATION ON BOTH SIDES 1-405) T1JRN EAST ON S.E. MAY VALLEY OF CHANNEL. ENHANCE OFF-CHANNEL WETLAND FISH ROAD. GO TO 148TH AVE S.E., TURN SOUTH HABITAT DOWNSTREAM OF 148TH AV TO BRIDGE OVER MAY CREEK. PATUM: AS STATED SCALE: NOT. TO SCALE S.E. . ASSISTANCE BY: LINDSEY MILLER SHEET: 7 OF 8 I NW~-l.OrO-\~ DRAWN BY: MEREDITH RADELLA DATE: AUG 13, 2010 ,---------------------------------------- .. ------~ LOG TABLE H of LOGS LOG SIZE LOG ROOTWAD OR LENGTH WITHOl!T (W/O\IT) FLOODPLAIN ROUGHNESS '0 12'"-14"dbh '0' w/out '0 12"-lS"dbh ",,' rootwods 60 totol ALCOVE AREAS 7 lB" -24· dbh ",,' rootwads 5 16'"-18'" dbh ",,' rootwads 4 12"-18'" dbh ",,' rootwads 16 total 76 total May Creek Stream and Wetland Enhancement Planting Plan - west of 148th Ave SE latin Name Common Name SizeiSpeclflcations Quantity Emergents .. for alcoves near stream '--eo-.... "'" (P\m112" o.c.) '00 -"., .... CrcqriD&JPiII:HWI1 P1uz(Plzlt12"O.c.) '00 c_lftpII/Q .. _-Plug (Plant 12" Q,C.) soo SbrubsIWilIOW9 2.~ Heiiht. 11· Root S~ Red-oiserdogwood Minimum4 twip.3Jiw: \lud$ """"'-PIaGI]' D.C. '" 24" HtiPI. 11~ RDat Sprca1 P1r)tfQCIJtpllS capilfJfUS Minimzml4 fWias. 3 live bwh hcille..mct.zrt. Pllllllro,c ,., 24" Heigh!, II" Root Sprelld IIrml pUoctJrp4 Swarnprosc: Mininnun4 twigs. 3 live buds Pbnll'O.C. '" 2"''' Heiaht, II" Roex Sprad Spin.~ dol¢l<Ufi """'" """ Minimum '" nrip,31i""buds Plant)' D.C. '" 14" Hd&ht. II" RootSprcad Rub..s .~ctablt;. SaImollbcny Minimum '" twigs. 3 live buds Plam3'O.C. '" LiveStaka Minirnwn 6(1--7r Loo& 3.'''-1" '"-M"mimum 6 \i"e bOO! Salk lasitmbD Pacif~ willow l'bIlll' a.c. ,~oo LivcSlallel Minlnuun 50" -72" l..oai 314-'" Oi~ Minimum6 live buds Slllixnmd"iluuJ ScouIcr'r ..,iUow PlaIlt2'O.C I.'" Lin pole ClI!I!na Minilll\Url72-_96-W Salix flUiMd.." hc;ifi~ willow Minimgm2 M .]-diamcu:r . 1,500 Uve pole euttina Minimum72w_96" Popu1,..Irichr;>CD.rptl B~Cotlonwood Minimmn 2w. 3" diamero:r 1,000 King County PURPOSE: REDUCE DURATION OF FLOODING PROJECT TITLE: ROPOSED WORK: ON PROPERTIES AOJACENT TO MAY CREEK; MAY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING BET'M:EN APPROX. RIVER MILE 4.3 AND .4.9. VEGETATION AND SEDIMENT FROM DIRECTIONS TO SITE: SHEET TITLE: MAY CREEK. PLANT 15' BUFFER OF FROM COAL CREEK PARKWAY. (EAST OF LOG AND PLANTING TABLES NATIVE VEGETATION ON BOlli SIDES 1-40S) TURN EAST ON S.E. MAY VALLEY OF CHANNEL. ENHANCE ROAD. GO TO 148lli AVE S.E .• TURN SOUlli OFF-CHANNEL WETlAND FISH TO BRIDGE OVER MAY CREEK. NOT TO SCALE HABITAT DOWNSTREAM OF 148lli AVI' DATUM: AS STATED SCALE: S.E. NI\)\-Pllo-I~ ASSISTANCE BY: LINDSEY MILLER SHEET: 8 OF 8 ORAWN BY: MEREDIlli RADELLA DATE: AUG 13._ 2010 '.;, i'- Jean Rollins 2905 Ilwaco Ave NE Renton, WA 98059 October 4, 2011 Mr. Phil Olbrecht Renton Hearing Examiner City of Renton 1055 South Grady way Renton, W A 98057 EXHIBIT 25 Re: May Creek Dredging Project-LUAll-065, V-H, SP Dear Mr. Olbrecht: Citations from scientific experts demonstrate that 9 of the 10 variance criteria to be used in the decision have not been met. Scientific statements in the record clearly provide there is an absence of valid scientific information and incomplete scientific information. Ibis invalid and incomplete scientific information regarding the critical area of May Creek and its associated wetlands requires the Hearing Examiner take a ''precautionary or a no-risk approach". (Renton Municipal Code 49-250 F.) Therefore, due to criteria not being met (90ut of 10) and invalid scientific information, we respectfully ask the Hearing Examiner deny the special permits. The following 5 documents will be referenced using the abbreviations in parentheses: Letter from Muckleshoot Indian Tribe Fisheries Division to Washington Department of Ecology dated May 11,2011 (MITFD 5-11) Memo from Dr. Patricia Olson, Senior Hydrogeologist to Rebekah Padgett Washington Department of Ecology dated August 15,2011 (Olson) Letter from Rebekah Padgett, Washington Department of Ecology to Doug Chin, WLRD(King County Water and Land Resources Division) dated Septemberl, 2011 (Ecology 9-1) Letter from Rebekah Padgett, Washington Department of Ecology to Doug Chin, WLRD (King County Water and Land Resources Division) dated September 22,2011. A copy is attached, as tl)is letter is not in the record (Ecology 9-22) Letter from Muckleshoot Indian Tribe Fisheries Division to Washington Department of Ecology dated September 15,2011. A copy is attached, as this letter is not in the record (MITFD 9-11) 5bJ. Public health & safety and welfare are not best served. Ibis project is attempting to drain horse pastures at the detriment offamily homes and sole access bridges. Dr. Olson, Senior Hydrogeologist a PHD with Ecology stated, " ... this hypothesis has not been tested using adequate data. Ibis conclusion wouldn't be an issue if there were not structures downstream, but there are." (Olson Page 3) Experts stated in their denial letter that the county does not know what will happen downstream. · " ... outstanding issues remain ... sediment transport and data about what will happen downstream." (Ecology 9-22 Page 5) Staff states the hydraulic analysis shows the proposed project will not further contribute to ongoing erosion on properties downstream. However, experts state this hydraulic analysis is inappropriate: " ... for a study related to accessing potential hazards such as damage to structures (Olson Page 3) and "As pointed out in WLRD documents, HEC-RAS sediment transport model cannot address variable sediment transport conditions and changing channel elevations (erosion and deposition). Experts assert the County's conclusion that this project will not further contribute to erosion is incorrect: "Since the sediment transport report and H&H study to rely on ... data that does not include adequate sampling points, I can not make a determination concerning potential for increased bank erosion downstream of the project area" (Olson Page 3) Dr. Olson goes on to say, "I disagree with the statement made in the H and H study that the increase in frequency of smaller floods is insignificant. The increase in frequency of these small floods could affect sediment transport dynamics." (Olson Page 3 -4) These unknown issues (erosion, increased frequency of flooding, sediment transport, sediment deposition and changing morphology of May Creek) jeopardize the health, safety and welfare of Renton residents downstream. 5b3.This project does not serve established indentified public needs. State and tribal experts reviewing this project are adamantly alarmed that this project will harm May Creek and its associated wetlands. Dr. Olson disagrees with many of the studies used and speaks to potential public harm downstream. "The studies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data." (Ecology 9-1 Page 5) Muckleshoot Tribe's fish biologist has repeatedly wamed adverse impacts could result. "As noted in all previous comments, MITFD is concerned that dredging May Creek will cause adverse impacts to salmon and their habitat. This project proposes to dredge 2,000 linear feet of May Creek and its associated wetlands in areas identified as salmon spawning and rearing habitat (May Creek Baseline Stream Conditions Report)" (MITFD 5-11 Page 1) "The Impact Analysis and Mitigation report {(WLRD's} clearly states the project will adversely affect Essential Fish habitat for Coho." (MITFD 9-11 Page 1) "If the County is going to conduct d.redging of May Creek to benefit existing livestock operations on private property then enforceable farm plans should be part of this project." (MITFD 9-11 Page 4) This project serves private properties not public needs. This project does not protect residential properties downstream; rather it places them in jeopardy! Harming downstream does not serve public needs neither does adverse impacts to May Creek nor its salmon rearing habitat. 5b4. Alternatives comparable in benefit to this project were not examined ,-----------------------------------_._-------- ------------------- Practical alternatives such as bullet 4 in Renton's stafi'recommendation regarding farm management plans were not seriously considered. In their May 11,2011 letter, the Muckleshoot Indian Tribe Fisheries Division listed potential alternatives on page 3. MITFD even quotes the KC code that, "property owners are required to have a farm plan with maximum densities oflivestock." Further, " ... more effort of the obvious land use and pasture related sediment sources and allow the May Creek more room to store and transport its sediment load, consistent with natural stream processes." (MlTFD 5-11 Page 2) Muckleshoot Indian Tribe Fisheries Division requested the County " ... exhaust all less impacting alternatives prior to dredging May Creek ... (MlTFD 9-11 Page 1) Dr. Olson's memo on page 2, suggests various options including a cost benefit analysis. Also on page 4, Dr. Olson states that King County should explore other options. The County used large projects as alternatives and justified this proposal by saying it was all the county could afford. The WLRD (King County Water and Land Resources Division) did not compare apples with apples. Those large scale alternative projects do not reduce flooding duration by a mere .04 %, as this project will do. The benefit of this proposal is very small. Other alternatives comparable in benefit were not examined. For example, farm management plans and critter pads. Alternatives comparable in benefit have been ignored. Given the minimal benefit of the proposal and the enormous cost of mitigation: what about the alternative of no action at all? Eighty percent of a 3.75-acre wetland will have to be disturbed. Why not consider taking no action and save taxpayers dollars? 5b5. The proposed action DOES NOT TAKE afflrmative and appropriate measures to minimize and compensate (or unavoidable impacts. The scientists at Ecology purport the models used do not adequately address erosion or deposition and hence WLRD does not know what will happen downstream: " ... outstanding issues remain including buffer, baseline data, sediment transport and data about what will happen downstream" (Ecology 9-22 Page 5) Dr. Olson disputes the erosion thresholds, and sediment transport numbers. Dr. Olson laments the lack of accurate studies as to where sediment volumes will be transported, downstream sediment deposition, an upstream sediment report, geomorphic analysis and an erosion report. On erosion thresholds she states, "This bias ... resulting in higher discharge to mobilize bedload." "The lower end of the range (73-150 cfs) estimated in the H and H study appears more realistic for the areas we observed." She continues, "As pointed out in {WLRD} documents, HEC-RAS sediment transport model cannot address variable sediment transport conditions and changing channel elevations (erosion and deposition)." Further, since the sediment transport report and H&H study rely on " ... data that does not include adequate sampling points, I can not make a determination concerning potential for increased bank erosion downstream of the project area." (Olson Page 3) Please review Olson page 3 & 4 under downstream bank erosion and geomorphic analysis. She disagrees with the insignificance of smaller floods to downstream areas. She disagrees with the sediment transport numbers. She states King County's expertise shoUld be consulted on this project. Dr. Olson ends her in-depth discussion of bank erosion, " ... the existing transport modeling should have independent review .... " (Olson Page 4) Ibis means WLRD needs to go outside their organization to have the modeling reviewed. Incorrect baseline data, disputed sediment transport study, the lack of a sediment deposition study and appropriate erosion study all strongly indicate WLRD does not know what will happen downstream. "The studies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data. (Ecology 9-1 Page 5) "Outstanding issues remain ... data about what will happen downstream" (Ecology 9-22 Page 5) "King County should utilize its geologic and geomorphic expertise and further evaluate adding sampling points and designing an appropriate sediment transport and erosion study." (Ecology 9- 22 Page 5) It is inconceivable after so much input by scientists that the County does not have the necessary appropriate sediment transport and erosion studies. Since baseline data, sediment studies and erosion studies are inadequate or incorrect and downstream impacts are unknown, appropriate measures to minimize and compensate for unavoidable impacts is not possible. 5b6. Loss of value and function of Mav Creek & its wetlands The scientific experts indicate there will be function and value loss of both regulated May Creek and associated wetlands: " ... adversely affect May Creek, its associated wetiands."(MlTFD 5-11 Page 2) " ... the extent of these mitigation measures is insufficient to mitigate for the permanent loss of59,800 square feet of instream and overhanging habitat/vegetation as a result of this dredging project. "Additional mitigation is needed to fully mitigate for the unavoidable environmental impacts from this project. (MlTFD 9-15 Page 1) "There appears to be a disconnection in the conclusions supporting dredging. A 5-16% increase in stream power for potential sediment transport events is not significant but a .04% decrease in flooding duration of SOds is significant enough to dredge. (Olson Page 4) Dr. Olson is stating she believes erosion could be increased by up to 15%. Ibis potential increase is without appropriate erosion, sediment transport (both upstream and downstream) and sediment deposition studies. The potential increase could be much higher based on appropriate and correct studies, which do not exist. Ibis is why Ecology stated WLRD is lacking, "data about what will happen downstream." The whole range of appropriate and correct data about what will happen downstream has not been gathered, and thus WLRD has produced flawed conclusions. "The stUdies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data." (Ecology 9-1 Page 5) "The Hydraulic and Hydrologic Analysis report suggests that the decrease in flood durations at 100 CFS is 7 hours which suggests little benefit for substantial environmental impacts to May Creek." (MITFD 5-11 Page 4) .---------- "The King County documents indicate that flood storage will be reduced in the project area, so additional flood storage to compensate for that loss should be included in the project." (Olson Page 4). 'The Long Marsh Creek mitigation project is not mitigation. Further" ... is not a restoration project but more of a drainage efficiency project..." (Olson Page 2& 3) "These alcoves are proposed as mitigation for lost instream fish habitat. If they fill in during high flows, then their mitigation value will be lost or substantially reduced. (MlTFD 9-11 Page 4) Mitigation proposed to compensate for loss function and value of both regulated May Creek and associated wetlands is not mitigation as declared by experts. Compensatory flood storage is not provided. For little benefit, a .04% decrease in flood duration versus substantial increases in erosion, stream value and function of May Creek and its wetlands will be lost. 5b7. Fish species are jeopardized Fish biologist in their submitted comments to the City of Renton avows various fish species will be jeopardized: "This project proposes to directly impact the natural process of sedimentation and floodwater storage along May Creek without adequately assessing the potential impacts to salmon and their habitat in the project area and in upstream and downstream areas." "There is no estimate given for the potential loss of rearing habitat" (MITFD 5-11 Page I & 4 ) "Salmon watchers program indicate that adult Chinook, sockeye and Coho were reported as fur upstream as Greene's Creek. .. " (MlTFD 5-11 Page 4) Greene's Creek is home to endangered, threatened or sensitive fish species. Greene's Creek is downstream in an area that Ecology says WLRD does not know what will happen if this project is permitted to proceed. Without quantifying the potential pre-and post project rearing habitat available for juvenile salmon in May Creek, it is not known which fish ( endangered, threatened or sensitive) utilize downstream rearing areas which may be negatively impacted by this project. Unknown loss of rearing habitat means the fish species are in jeopardy. 5b8. Water Quali/vDegradation Ecology denied WLRD the 40 I certificate since WLRD did not demonstrate with reasonable assurance that water quality standards for surface water of the State of Washington will be met. (Ecology 9-22 Page 2) " ... outstanding issues remain including buffer, baseline data, sediment transport and data about what will happen downstream" (Ecology 9-22 Page 5) Baseline data, sediment transport, upstream sediment report (not done) and what will happen downstream {erosion, deposition, downstream channel response, sediment transport dynamics} were all found lacking by Ecology. These flaws in this project could negatively affect the surface water quality of May Creek. Further, impacts to groundwater including the wells in the downstream areas of May Creek have not even been addressed. 5b9. This poject requires more than a minimum variance (or an unlikelv desired purpose Throughout this whole process, the effectiveness of this project has been strongly questioned. The Army Corp of Engineers and Ecology has repeatedly stated and written that they question the very ---~ -----------_ ... need and purpose of the project. The desired purpose being met is unlikely and oflittle benefit as expressed by the reviewing scientists: " ... one time dredging will not solve the flooding extent and duration over time. LiDAR data indicate that there are large floodplain areas below the channel elevation." "These conditions suggest that dredging is somewhat akin to trying to channelize a bathtub where water inflow is greater than water outflow." (Olson, Page 1) Ecology reaffinns Dr. Olson's input " ... Ecology believes the effectiveness of the proposed action for the stated intent of decreasing the duration of surface water on the grazed wetlands: Has not been fully demonstrated to merit the level of impacts proposed for .04% decrease in flooding duration of 50 cfs and ... no upstream sediment study has been provided ... ," (Ecology 9-1 Page 4) Even as late as the denial letter on 9-22 Ecology required, "Reassessment and redesign of the project to address its effectiveness ... " (Ecology 9-22 Page 2) A voidance of adverse impacts has not been accomplished by this project. The scientific experts repeatedly assert that the project is lacking necessary studies. They maintain the studies that are available are inappropriate, incorrect, or insufficient. Compensatory flood storage is not provided. Therefore, the adverse impacts of this project are not known. These flaws make it highly unlikely this project is avoiding significant adverse impacts to critical areas. The MITFD continue to stress the extent of these mitigation measures is insufficient to mitigate for the permanent loss of 59,800 square feet of instream and overhanging habitat/vegetation. Ecology believes this project does not merit the level of impacts proposed. 5blO. Lack of Best Available Science. The scientific information used in the baseline data; stream transport, downstream erosion and modeling have been invalidated by state scientific authorities: "WLRD has well qualified fluvial geomorphologists and geologists on staff; however, it does not appear they were consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomorphic processes that create the current conditions, the downstream channel response including migration to changes in flow and sediment regimes." (Ecology 9-1 Page 5) The Long Marsh Creek Mitigation plan is not a mitigation plan according to Dr. Olson. 'The Long Marsh Creek mitigation project is not mitigation." (Olson Page 2) The mitigation for dredging including the alcoves according to the MITFD is insufficient. "These alcoves are proposed as mitigation for lost instream fish habitat. If they fill in during high flows, then their mitigation value will be lost or substantially reduced. (MITFD 9-11 Page 4) Compensatory flood storage is not provided. "The King County documents indicate that flood storage will be reduced in the project area, so additional flood storage to compensate for that loss should be included in the project." (Olson Page 4) "No upstream sediment study has been provided ... ," (Ecology 9-1 Page 4) "The project is re-dredging portions of May Creek dredged last in 2002 "with no data collected afterwards. (MITFD 9-15 Page 4) It is not Best Available Science to subject a creek to dredging and not monitor the effects. The lack of the use ofWLRD expertise to design this project is alarming to Ecology. Scientists have purported that best available science has not been used to design, understand, or mitigate this proposal. Conclusion This project embodies alarming scientific issues and flawed conclusions based on inappropriate, insufficient, incorrect data and information. Ecology has upheld their serious scientific issues with denial of the 401 certificate. Ecology clearly substantiates that WLRD does not know what will happen downstream. For little benefit, a .04% decrease in flood duration; verses substantial increases in erosion, stream value and function of May Creek and its wetlands will be lost. This project's potential detriment to downstream, May Creek and its wetlands far outweighs the private property benefit. These are not my conclusions, rather the conclusions of expert scientists, such as a PhD Hydrogeologist, fish biologist and wetlands biologist. Downstream of this project are homes and bridges in Renton. We citizens are faced with negative impacts involving safety, erosion and flooding. The reviewing scientists have validated all of our fears and more. Citations from scientific experts reflect that 9 of the 10 variance criteria in Renton's code have not been met. Experts' statements reveal this activity would be unreasonably detrimental to the surrounding area. Scientific statements in the record clearly provide there is an absence of valid scientific information and incomplete scientific information. This invalid and incomplete scientific information regarding the critical area of May Creek and its associated wetlands requires the Hearing Examiner take a "precautionary or a no-risk approach". Therefore, we respectfully request the Hearing Examiner not grant a variance or special permit. Thank you for your thoughtful consideration in this manner, l.{..a. ~ 2. s-U~ J~Roliins Enclosures: Letter from Muckleshoot Indian Tribe Fisheries Division to Washington Department of Ecology dated September 15, 2011 Letter from Rebekah Padgett, Washington Department of Ecology to Doug Chin, WLRD dated September 22, 2011 MUCKLESHOOT INDIAN TRIBE Fisheries Division 39015 -172nd Avenue SE • Auburn, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 September 15,2011 WashinRton Department of Ecology-SEA Progmm Federal Project Coordinator P.O. Box 47600 Olympia, W A 98504 RE: May Creek Drainage Improvement Project, revised project, 401c and CZM Consistency Public Notice of Application Dear Sir or Madame: ,-. The Muckleshooi Indian Tribe Fisheries Division (MITFD) has reviewed the Public Notice of Application for a State of Washington 401 Water Quality Certification and Coastal Zone Management Act Consistency for the May Creek Drainage Improvement Project. This project is the first of potentially four phases to dredge May Creek inMay Valley. In this first phase, the project proposes to dredge May Creek from River Mile 43 .to River Mile 4.9, removing sediments, reed canarygrass, and some of the existing willows that iu"e Within and adjacent to May Creek. As noted in all previous comments, MlTFD is concerned that dredging May Creek will cause adverse impacts to salmOn and their habitats. The Impact Analysis and Mitigation report clearly concludes that this project will adversely affect Essential Fish Habitat for coho. In addition, this is the first of potentially four dredging projects that would result in the dredging of2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. The combined impact of all of these dredging projects would likely result in a significant loss of existing salmon habitat, and potentially future adverse impacts upstream and downstream from the dredged reaches as other landowners seek to protect their properties from bank erosion or sediment deposition and flooding. Again, we recommend that King County implement and exhaust all less impacting alternatives prior to dredging May Creek discussed further in the attached comments. While the proposal to fence and plant native wetland! riparian vegetation and create alcoves with wood and sediment is an improvement over the existing-conditions for most of the project area, the extent of these mitigation measures is insufficient to mitigate for the permanent loss of 59,800 square feet of jnstream and overhanging habitat! vegetation as a result of this dredging project. The proposed IS' . planting buffer on both sides of May Creek, including the mitigation site that is an open space tract, is significantly leSs than Renton or King County's regulated buffers and will be insufficient to provide the Muckleshoot Indian Trtbe Fisheries Division Comments to May Creek dredging Public Notice for 401c and CZM Seplember 15, 2011 Page 2 full suite of riparian functions. Additional mitigation for this project is needed to fully mitigate for the unavoidable environmental impacts from the project. We remain concerned that this project is a "short term fix" and that there is a high likelihood that additional dredging will be proposed here and elsewhere in May Valley that may again adversely affect May Creek, its associated wetlands, and potentially the mitigation implemented for this project. Instead we recommend focusing more effort on the obvious land use and pasture-related sediment sources and to allow May Creek more room to store and transport its sediment load, consistent 'with nat.rral stream processes. Additional specific comments and questions about this project are attached for your review and consideration. Please let me Y~'10W if you have any questions at 253-876-3116, Sincereiy, " ,; )!..) J,.!i·:<:<~ Karen Walter Watersheds and Land Use Team Leader Cc: Lori Lull, USACOE Randy McIntosh, NMFS Larry Fisher, WDFW Region 4 Rebekah Padgett, WDOE, NW Region Patrick McGranger, WDOE, NW Region Dave Garland, WDOE, NW Region Jennifer Henning, City of Renton Planning Doug Chin, King County DNRP Jamie Hartley, King County DOES Muckleshoot Indian Tribe Fisheries Division C9mments to May Creek dredging Public Notice for 401c and CZM May Creek 40 I (c) and CZM comments September 15, 2011 Page 3 1. We agree with the WDFW's issued HPA permit condition that requires rounded boulders, cobbles, and gravel proposed to protect the outlet of Long Marsh Creek instead of the quarry spalls riprap shown on Sheet 4 of the July 20, 201 1 drawings and Sheet C2 of the 70% Design Plans. A new project drawing should be submitted to reflect these changes. 2. Any tree equal to or greater than 4 inches diameter (OBH) and removed from within 200 feet of Long Marsh Creek or May Creek should be placed back into Long Marsh Creek or May Creek downstream of 148th Ave SE to partially mitigate for the temporal impacts from their removal. The Impact Analysis and Mitigation Plan states that sixteen trees over 6 inches DBH will be removed along Long Marsh Creek (page 16). Tnere may be more once May Creek is considered. 3. The 2001 May Creek Basin Plan Appendix H analyzed dredging in some detail and made several conclusions: • A dredged channel of 1.5 feet in depth and 11 feet in width with a planted 61 foot wide floodplain bench would need to be dredged and replanted every 20 years at an estimated maintenance cost of2.8 million dollars from 2001 estimates; e Increasing the stream gradient to minimize sediment deposition and maintenance would require dredging 9 to 32 feet; • Dredging would compromise the bridges at 14Sth Ave SE and I 64th Ave SE and their replacement was identified as a necessary element of any dredging project; • If a dredging project moves water more quickly out of May Valley, then peak flows in the d01'<'l1stream reaches of May Creek would significantly aggravating an existing erosion problem in May Creek canyon, thus requiring detention ponds that would cover 23 acres or 113 oft.J.,e existing May Valley eliminating riparian and wetland habitat; and • Appendix H also noted that dredging May Creek would likely drain 100 of the estimated 142 acres of May Creek Wetland 5. It is riot apparent that much has changed since King County completed the Final 200 I May Creek Basin Plan leading to the conclusions above including additional information in the 2008 May Creek Drainage and Restoration Plan. For example neither bridge is proposed to be replaced. King County should discuss each of these bulleted items and explain in detail what has changed or what new analysis exists to refute these earlier conclusions, 4.· Of the alternatives identified in King County's responses to the previous MITFD 401c comments (letter dated May 11 2011), additional information and a!lalysis should be provided to support the Muckleshoot Indian Tribe Fisheries Division Comments to May Creek dredging Public Notice for 401 c and ClM September 15, 2011 Page 4 statement that the "implementation of farm management plans, including construction of farm pads would have more long-term adverse impact on critical areas", including instream habitat for salmon than dredging May Creek here and at the future sites upstream, 5, King County has code authority to require farm management plans under 21A.30.070 (see King County's responses to MITFD 401c comments). lfthe County is going to conduct dredging of May Creek to benefit existing livestock operations on private property, then enforceable farm plans should be part of this project. 6. We request a copy of the survey data from the Long Marsh and May Creek sediment removal projects (see King County's responses to MlTFD 401c comments). 7. More wood should be added to Long Marsh Creek to provide sediment storage, including channel spanning logs to meter sediment transport and deposition, 8. The McFarlandlGambini footbridge needs further analysis to demonstrate that it is not causing a backwater effect and allowing gravel to deposit into May Creek causing one identified obstruction. If the bridge is causing a backwater effect, then the new 100 foot side channel and channel meandering in Long Marsh Creek will not resolve this problem and sediment deposition at the confluence will continue. Instead, the footbridge should be modified to accommodate the gravel load or removed during overbank flooding to allow sediment movement in May Creek. 9. In King County's 2010 responses to the MlTFD and WDOE SEPA conunents, the County suggests that the proposed mitigation alcoves downstream of I48th Ave SE will allow sediment to deposit outside ofthe main channel at higher flows. These alcoves arc proposed as mitigation for lost instream fish habitat. If they fill in during higher flows, then their mitigation value will be lost or substantially reduced. Additional analysis is needed to demonstrate that these alcoves will not fill in and if so, what additional mitigation will be provided. 10. The plan sheets (Sheet 14 of70% design) show only a portion of the existing open space tract west of l48th Avenue SE being enhanced. Additional mitigation needed to meet the "no net loss" standard for wetland and stream impacts could occur here, including expanding the wetland mitigation area and enhancing Green Creek that flows into the mitigation site. 11. The project is re-dredging portions of May Creek dredged last in 2002. Unfortunately, no data was collected regarding effects on salmon, flooding and sediment accumulation, nor were as-built drawings prepared (see King County's response to MITFD dated December 22,2010), All we know is that whatever work completed in 2002 was not sufficient to avoid dredging 10 years later. We are concerned that the project will not function as designed requiring more frequent dredging than modeled. At a minimum, the Construction Waler Quality Protection and Monitoring Plan needs to be modified as follows: Muckleshoot Indian Tribe Fisheries Division r.nmmAn'" '0 Mav Creek dredalna Public Notice for 401c and CZM September 15. 2011 P,,!!e 5 • Monitor sediment accumulation and erosion in May Creek, including downstream in the M~v Creek ravine: • Col1ect data to document changes in channel cross-sections and longitudinal profiles; and • Collect data to document that the flood frequency durations were reduced as predicted. • The project should also monitor for adult and juvenile salmon use this year and post cnn8tmction. • Any project deficiencies shoul4 be addressed through an enforceable contingency plan. 12. We request a copy of the Draft Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report that was referenced but not included with King County's responses to our May 11 2011 comments. 13. We are still very concerned that the 15 foot mitigation riparian vegetation buffer will not provide the suite of riparian functions needed to create and maintain salmon habitat. As 15 foot riparian buffer is also inconsistent with KCC 21.AJO.045.B and the farm plans that exist for 2 of the project's properties. A minimum 25 foot buffer on all properties benefiting from this project should be provided as a partial "out of kind" mitigation measure for this project's adverse impacts to salmon habitat documented in the Stream and Wetland Impact Analysis and Mitigation Plan (KC 2011). The open space property downstream of 148th Avenue SE should have a riparian buffer of at least 100 feet as required by the City of Renton's Critical Areas code. STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office 3190 160th SE Bell",.., .. Washil/g/oll 98008-5452 (425) 649-7000 September 22, 2011 Doug Chin, Project Manager King County Water and.Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 RE: Ecology Denial for Section 401 Water Quality Certification fortlte May Creek Drainage Improvement Project, Renton, King County, Washington Dear Mr. Chin: The U.S. Anny Corps of Engineers (Corps) issued a joint public notice with tlte Washington State Department of Ecology (Ecology) for the above project on September 24, 2010. Ecology has one year to issue an individual Section 401 Water Quality Certification (401 Certification). On August 31, 2010, Ecology notified you by celiified letter that this project would require a 40 I Certification. On April 21, 2011 and September I, 2011, Ecology issued additional public notices regarding King County's two revised applications for 401 Certification. We detennined that your application for an individual 401 Certification was incomplete and sent you a certified letter on September 1, 2.011 detailing the specific infonnation that was needed to complete your application and stating that if Ecology did not receive all of the required documentation by September 16, 2011, Ecology would deny the 401 Certification for this project. In our September I, 20 II letter we identified the following infonnation needed in order to complete our review: • A description of how sediment disposal areas will be stabilized. • A Construction Water Quality Protection and Monitoring Plan. • Measures to be taken regarding stream water temperature changes between removal of mature vegetation and when replanted vegetation reaches the size to shade the creek. • Revisions to the Mitigation Plan. • Revisions to the sediment monitoring plan. • Site plan revisions. . • Details on the Long Marsh Creek riparian planting buffer. • A copy ofthe Final Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report. • . Expanded riparian vegetation buffers. • Study of the resizing or removal of the 148'h Avenue SE BIidge. IGng County Water and Land Resources Division . September 22, 2011 Page 2 • Reassessment and redesign of the project to address its effectiveness, including further evaluation and study of sediment transport and downstream erosion, as well as independent review of sediment transport modeling. On September 16,2011, Ecology received a response addressing some of the information requested. Unfortunately we have not rec.eived all of the documentation needed in order to demonstrate that we have reasonable assurance that state water quality standards will be met:"We have attached a project chronology that details that we have been trying to work with you to get the needed information in order to process your request for a 401 Certification.· Pursuant to Section 401 of the Clean Water Act, ch. 90.48 RCW and ch. 173-20 lA WAC. the May Creek Drainage Improvement Project water quality certification is denied without prejudice. Receipt of a denial without prejudice does not preclude King County Water and Land Resources Division from resubmitting a request for 401 Certification at a later date. You have a right to appeal this Order to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this Order. The appeal process is governed by Chapter 43.21B RCW and Chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.001(2). To appeal you must do the following within 30 days of the date of receipt of this Order: • File your appeal and a copy of this Order with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. • Serve a copy of your appeal and this Order on Ecology in paper form -by mail or in person. (See addresses below.) E-mail is not accepted. You must also comply with other applicable requirements in Chapter 43.21B RCWand Chapter 371-08 WAC. Department of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, W A 98503 Pollution Control Hearings Board 1111 Israel Rd SW STE 301 Tumwater, WA 98501 Department of Ecology Attn: Appeals Processing Desk PO Box 47608 Olympia, WA 98504-7608 Pollution Control Hearings Board PO Box 40903 Olympia, WA 98504·0903 ------------------------------- King County Water and Land Resources Division September 22,2011 Page 3 . Please direct all questions about this Order to: Rebekah Padgett Department of Ecology Northwest Regional Office 3190 1 60th Avenue SE Bellevue, WA 98008 (425) 649-7129 Rebekah.Padgett@ecy.wa.gov Pollution Control Hearings Board Website www.eho.wa.govlBoards PCHB.aspx Chapter 43.21B RCW -Environmental Hearings Office -Pollution Control Hearings Board http://apps.leg.wa.govIRCW/default.aspx?cite=43.21B Chapter 371-08 WAC -Practice and Procedure http://apps.leg.wa.gov/wAC/default.aspx?cite=371-08 Chapter 90.48 RCW -Water Pollution Control http://apps.leg.wa.govIRCW/default.aspx?cite=90.48 Chapter 173-201A WAC -Water Quality Standards for Surface Waters of the State of Washington www.ecy.wa.govlbiblio/wacl73201A.html Erik Stockdale, Unit Supervisor Wetlandsl401 Unit Shorelands and Environmental Assistance Program Northwest Regional Office ES:rrp:cja Enclosure By certified mail 7011 047000033720 9107 September 22, 2011 King County Water and Land Resources Division September 22, 2011 Page 4 cc: Lori Lull, U.S. Army Corps of Engineers TJ Stetz, U.S. Army Corps of Engineers Larry Fisher, Washington Department ofFish and Wildlife Karen Walter, Muckleshoot Indian Tribe Katie Bonwell e-cc: Patrick McGraner -NWRO Patricia Olson -HQ Loree' Randall-HQ Raman Iyer -NWRO ecyrefedpennits@ecy.wa.gov Jennifer Henning, City of Renton Jhenning@Rentonwagov Jean Rollins urbanseparator@hotmail.com Debra Rogers herogers@comcast.net Susan Malin susiemalin@mso.com Gary Amundson gary.a@comcast.net Andrew Duffus klassicars@hotmail.com Carol Tabacek caroltabacek@aol.com Mary Weirich maryvweirich@comcast.net A. Duffus blueheron6987@hobnail.com Julie & Jim Bonwell jbonwell@lesourd.com I 1126/10 2122110 3124/10 515/10 5113/10 6124/10 Attachment 1: May Creek WQC Permitting Chronology Ecology attended an interagency meeting organized by King County with discussion about the 'potential to create a multi-agency permitting team. A brief introduction and overview of the project concept at this early stage was presented. The U.S. Anny Corps of Engineers (Corps), Ecology, Washington Department of Fish and Wildlife (WDFW), Muckleshoot Indian Tribe, Governor's Office of Regulatory Assistance, and King County representatives were present. Ecology attended a field meeting with King County, WDFW, and the Muck1eshoot Indian Tribe. Ecology staff raised concerns about the effectiveness, purpose and need of the proposed project. Specific comments included: the effectiveness of the IS-foot-wide buffers, concerns about direct animal access to stream, severely degraded pastures and the need for fann plans, extent of the wetland and primary sources of hydrology, and concerns about establishing woody vegetation in very wet soils. Ecology observed that livestock have direct access on one of the project properties upstream of the project area. Ecology provided written comments via e-mail that followed up on the 212211 0 site visit. Ecology participated in an interagency pre-application meeting and provided substantive comments regarding the effectiveness, purpose, and need of the project, as well as the need to redelineate the wetland, buffer width, and limit livestock access to the creek. Ecology raised concerns about 303( d) listing for, fecal coliform and the preference for 35-foot buffers and wider planting on the south side buffer to reduce summer temperatures through shading. Ecology questioned the 2002 pilot described by King County where two sediment plugs were removed from side channels on the McFarland property, specifically whether it would be comparable to the C\lITent proposal and what post- construction monitoring was completed. Ecology raised the question of whether the proposed one-time dredging would accomplish the goals of the proposal; the County indicated that it was planning a series of projects, working from this site upstream. Ecology also pointed out that the baseline stream report included language that contradicted and would not support this proposal. Downstream erosion concerns were discussed, and King County staff noted that they had conducted modeling and did not believe that the sediment removal would increase erosion downstream. King County submitted the Joint Aquatic Resources Permit Application (JARP A) package to Ecology. The Corps canceled the application. Ecology canceled the 40 I application based on the Corps' 5/13/10 action. ,---------------------------- King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment 1 September 22, 2011 Page 2 8116/10 9/8/10 9/16/10 9120110 9/22/10 9124110 10110 10/23110 12/16/10 313/11 3118/11 King County submitted a revised JARPA to Ecology. King County submitted a Certification of Consistency with the Washington State Coastal Zone Management (CZM) Program to Ecology. Ecology submitted comments on the State Environmental Policy Act mitigated determination of non-significance (MONS) regarding effectiveness, purpose, and need of the proposal, buffer width, how wet the left bank is in Reach 4 for establishing canopy cover, the degradation of the pastures and need for farm plans to protect riparian habitat and creeks, and livestock access to the creek. Ecology received substantive public comments from downstream residents. Issues raised included concerns about increased erosion, sediment transport thresholds, cumulative impacts, and the need for additional detailed study of the potential downstream impacts. Ecology received substantive public comments from the Muckleshoot Indian Tribe raising concerns about net loss of habitat, downstream erosion, insufficient buffers and the probability that the proposed dredging will be a sholt-term fix. Corps issued a joint public notice with Ecology. Ecology received substantive public comments from downstream residents. Issues raised included concerns about the purpose and need of the project, draining of wetlands, water quality, salmon habitat, increased flow, and bank erosion, as well as questions about the 2002 pilot. Ecology received substantive public comments from the City of Renton that included concern about effects of increased velocity, flow, or erosion on downstream properties. Ecology received King County's responses to Ecology MONS comments. In the response letter, the County defends the proposed 15-foot buffer not as best available science (BAS) but liS an improvement over existing conditions citing property owners' reiuctllnce to expand planting areas, states that it cllnnot require farm plans from private property 01!'1ler~ or require owners ~vith fann plans to implement them properly, and notes that the planting areas will be fenced and will therefore effectively eliminate livestock access to the creek. Ecology lind King County jointly extended the CZM review period until 9/8/11. King County submitted another revised JARPA to Ecology. This revision included new impacts to Long Marsh Creek that the County referred to as mitilation, therefore reducing proposed mitigation downstream of 148 Avenue SE. King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment 1 September 22, 20 II Page 3 4/5/11 4121111 4/26/11 4/28/11 5/11 5111111 Ecology received substantive public comments from the Neighbors Jor ]'t[ay Valley, who raised concerns about stream flow velocity, volume and timing of storm events, flooding and erosion. Downstream property owners requested that King County allow the project to be delayed at least one water year to establish a pre-project erosion baseline. The downstream citizens requested additional assurances that the proposed dredging will not have unintended negative consequences to downstream properties. Ecology issued a public notice on the revised application. Ecology participated in an interagency site visit where staff raised questions about the effectiveness, purpose, and need of the project, permanent protection of the mitigation area, the buffers on Long Marsh Creek, whether the Long Marsh Creek work was really mitigation, project-specific monitoring of sediments in the project area and downstream, best management practices, proposed buffer widths, how wet the left bank is in Reach 4, and the need for future dredging. Ecology followed up bye-mail documenting questions raised at the 4/26/11 site visit. Ecology received substantive public comments from downstream property owners questioning assumptions being made by King County based on modeling within the Hydraulics and Hydrologic Analyses using limited data, expressing concerns about downstream erosion, increased turbidity, and the proposed IS-foot planting buffer as not meeting BAS or County code. Specific questions also were raised with regards to the adequacy of the information provided by King County that claimed that the 2002 pilot project along a 300-fool section of the creek upstream ofthe proposed project was successful, erosion thresholds, potential for shallow well contamination, flow velocity, volume and peak flow during storm events potentially risking sole-access bridges to properties, and the adequacy of the 15- foot planting buffer. Ecology received additional substantive comments from the Muckleshoot Indian Tribe emphasizing the need to improve pasture conditions and control other existing sediment sources through agricultural best management practices and/or farm plans, minimize the dredging area ,vith increased mitigation for impacts, increase the proposed planted buffer width, provide additional riparian plantings, measures to avoid impacts to downstream reaches, mitigation for any unavoidable impact to downstream reaches, future dredging projects, and potential impacts to salmonids. King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment I September 22, 2011 Page 4 6110/11 711111 718/11 7/19/11 7122111 Ecology received King County's responses to Ecology's 4126/11 and 4128/11 comments. In its letter, King County stated that downstream impacts have been sufficiently analyzed and that a formal monitoring plan is not warranted; based on previous analysis and current design features, re-sedimentation monitoring is not ",arran ted at this time; and there are no future plans to implement additional upstream sediment removal projects. King County continued to defend the proposed 15-foot buffer as being adequate even within the very wet portion of the left bank in Reach 4. In response to ongoing concerns from Ecology regarding the effectiveness of the proposed project, King County again stated that the project is only designed to reduce overbank pasture flooding for a short period of time on each end of the rainy season and that monitoring wells have been installed to assess groundwater pre-and post-project. Ecology received King County's responses to a public comment in which the County restated that the I5-foot proposed planting buffer, while not based on BAS, is an improvement over existing conditions as demonstrated by the results ofthe 2002 pilot project upstream of the current proposal and that the continuous hydrologic watershed mode used accounted for all peaks, all durations and all . flow rates at all locations. King County reversed its position from 6/10111 and . agreed to conduct downstream monitoring for a period of 5 years post-project. Ecology responded to King County by requesting a copy of the downstream monitoring plan with note that the plan should be comprehensive and not simply address the issues raised by one property owner. Ecology received King County's responses to a public comment in which the County stated that downstream monitoring will be conducted for a period of 5 years and that if monitoring data collected clearly shows that erosiun problems result from the .project, that it will offer technical assistance and perform remediation. The County indicated that it has no future plans to implement additional sediment removal projects upstream of this project site. Ecology received King County's responses to a public comment stating that the project will not increase existing erosion problems downstream, proposing 5 years of downstream monitoring and working with the property owner on a solution if the monitoring shows downstream erosion resulting from this project. Ecology received King County's responses to the Muckleshoot Indian Tribe 5111/11 comments. The e-mail states that the COlmty does not have plans to implement the other three upstream dredging projects. In response to the tribe's comment that King County Code requires existing livestock operations to implement a farm management plan or meet management standards outlined in the Code, the County indicates that two of the four livestock operations have developed plans and that the buffers specified in these plans are 25 feet (10 feet more than the County is proposing through this project). The County also acknowledges that the 148th Avenue SE Bridge causes a backwater effect. · , King County Water and Land Resourcel! Division May Creek Drainage Improvement Project Attachment I September 22, 2011 Page 5" 7/26/11 8/2/11 9/1/11 9/7/11 "J- 9/14/11 9/15/11 9/16/11 Ecology again visited the project site, including downstream properties. King County submitted another revised JARP A. The revision addresses Long Marsh Creek impacts and includes additional mitigation. Ecology sent a letter by Certified Mail to Doug Chin requesting additional' information and stating that project 401 Cel1ification would be denied if the requested documentation was not received at Ecology by September 16, 2011. Ecology issued a public notice on the revised application. Ecology and King County jointly extended the CZM review period until 11/8111. Ecology received a public COnmlent from a property owner reiterating questions about the need for the project and concerns about downstream erosion and flooding impacts Ecology received public comments from a property owner reiterating concerns about downstream erosion and flooding impacts, raising the need for additional erosion monitoring and stream flow devices, and questioning the need for the project. The property owner raises questions about the stream and wetland buffer width, storm surge flows, hydraulic and hydrologic analysis, cumulative impacts, compensatory stormwater storage, and the need for additional data and analysis. Ecology received public comments from the Muckleshoot Indian Tribe reiterating concerns about salmonids and habitat, cumulative impacts, likely future dredging, insufficient buffer widths, and the adequacy of mitigation. The letter also notes the need to consider less-impacting alternatives, have enforceable farm plans in place, for fwiher analysis on backwater effect of the McFarlandlGambini footbridge, to consider impacts of sediment deposition in the mitigation alcoves, for sediment accumulation and erosion monitoring, to collect data regai'ding changes in channel cross-sections and longitudinal profiles and data on flood frequency durations, to monitor for sal1nonid use, and for a contingency plan. Ecology received additional public comments reiterating concerns about downstream flooding and erosion. Ecology received King County's responses to the 9/1111 letter requesting additional information. While some questions were addressed, outstanding issues remain including: buffers, baseline data, and sediment transport and data about what will happen downstream. . Gerald Wasser From: Sent: To: Subject: Mr. Wasser, urban separator [urbanseparator@hotmail.com] Friday, September 09, 2011 2:27 PM Gerald Wasser May Creek Dredging ProjectlLUA11-065, V-H, SP EXHIBIT 13 I respectfully request that the City of Renton deny King County a "Special Permit for Grade/Fill and a Critical Area Variance". The project is in a critical area. The downstream area that this project may potentially negatively impact is also a critical area! The downstream area was prezoned one dwelling per acre and declared an urban separator for good reasons: the presence of May Creek, and erosion and flooding in this area of May Creek. Both the County and the City recognize this urban separator designation. As Alex Pietsch once said, the City received more input regarding creating the May Valley Urban Separator than they did for the whole Boeing rezone. Our community has lived by May Creek and along side the steep slopes of the ravine that surround May Creek for many years. We know the sensitivity of this environmentally critical area. We have supported its protection amid concerns for the landscape and negative impacts to our own lives. We care deeply about our environmentally sensitive area. In fact, we gave up the potential economic gain of higher dwelling density by supporting the urban separator concept. We believe this project will exacerbate downstream flooding and erosion. As a community, we have been communicating these serious concerns to all agencies involved since May 2010. As a result, the county has revised the project several times. Nevertheless, ·it is still not good enough. To address concerns, the Washington State Department of Ecology sent a hydro-geologist to site visit the downstream properties. Doctor Patricia Olson, the sole departmental hydro-geologist for all of Washington State, typically reviews much larger scaled projects. In her report dated August 15th, 2011, she questioned, among other things, the very effectiveness of the project and erosion and sedimentation thresholds values assumed downstream. Subsequently, on September 1st, 2011 state Ecology notified the county that the proposed project is lacking and Ecology will deny the permits if not revised. I urge the City of Renton staff and hearing examiner to request Dr. Olson's memo and Ecology's letter directly. We ask that the City of Renton deny the permits requested by King County and support its own citizens in assuring that this project will not increase flooding and erosion downstream. We have new erosion pins placed in February 2010 and a new stream gauge (37H) in place in the center of the downstream properties. Monitoring these erosion pins and gauge for 1 water year with above average rainfall would enable a better understanding when erosion occurs in our community. We ask the City of Renton to support its' citizens and require this monitoring before this project is allowed to proceed. Thank you, Jean Rollins 1 ,----------------------- Gerald Wasser From: Sent: To: Subject: Attachments: Hello Mr. Wasser: ------------------------------------------- A DUFFUS [klassicars@hotmail.com] Friday, September 09, 2011 11 :35 AM Gerald Wasser EXHIBIT 14 May Creek Drainage Improvement Project LUA11-065, V-H, SP Cityof rentoncomments090911.doc; FINAL May 5 -May Creek Summary 05251 O.doc; May Creek residence sandbagged.jpg; May Valley Pasture Storm 201 O.jpg; Trees & property lost FOREVER.jpg; May Valley Temporary Pasture Flooding Storm 2010.jpg; Home in Peril.jpg Attached please find my comments and question regarding this King County dredging proposal. Depending on how it goes I may send the photograph attachments to my letter separately. Also the Meeting Notes from the Office of Regulatory Assistance. (ORA) Thank you. Andrew Duffus p.s. looks like everything uploaded fine. Should be one letter, one meeting's notes ORA and five (5) photographs. 1 2905 Ilwaco NE Renton, WA 98059-3764 September 9th, 20 II Gerald Wasser, Associate Planner Department of Community & Economic Development City of Renton Renton City Hall 1055 South Grady Way Renton, W A 98057 VIAE-MAIL RE: May Creek Drainage Improvement Project ILUAII-065. V-ESP Dear Mr. Wasser: King County Water & Land Resources Division proposes to dredge and/or remove reed canary grass and native willows between river mile 4.3 and 4.9 on May Creek. The goal of this ill-conceived project is an attempt to improve drainage on three horse pastures that are located within a wetland. Many downstream property owners, (all citizens of Renton) are apprehensive that this proposal may exacerbate stream flow velocity, volume and peak flow timing during storm events. (Footnote I) There are severe and well documented flooding and erosion issues downstream that put our homes, properties and sole access bridges in peril. (please see photographs attached.) Due to easement restrictions and development patterns, there is no way to access our properties other than private bridges across the creek. Recently the Washington State Department of Ecology conducted a review of the downstream issues. Their conclusion was that King County's project failed to provide the appropriate level of detail for potential downstream impacts. While we are less concerned about the removal of non-native invasive vegetation and replacement with native species suitable for stream bank stabilization and fish habitat, we are very concerned with the proposal to dredge, which we believe, will increase downstream flow during storm events. We are not isolated. Many of our concerns were echoed in an inter-agency meeting for the proposed project held on May 5, 20 I O. (See attached "Final Meeting Notes" ORA) Personnel from the City of Renton, two King County departments, the conservation district, state fisheries and ecology, the Muckleshoot Tribe and the U.S. Army Corps of Engineers attended this meeting. Several agencies expressed concern that this project was more about drainage of horse pastures than enhancement of May Creek and its associated wetlands. Questions asked regarded "buffers, repeated sedimentation, downstream impacts, inadequate mitigation," etc. During the past 16 months, the county has attempted to address some of those concerns. However, we do not believe that all issues are adequately resolved. As stated above the state Department of Ecology has recently concluded that King County's project failed to provide detail for potential downstream impacts. I am reiterating some of the unanswered questions of downstream property owners and public agencIes. 1. Proposed stream and wetland buffer width? 2. Timing of May Creek storm surge flows? 3. Downstream bank erosion and destabilization of infrastructure? 4. Cumulative impacts of similar future proposed projects? 5. Ephemeral nature of this proposed project? First question, why is the county proposing only IS-foot mitigation buffers? My property straddles May Creek. When I applied for a pennit to build a garage located over 300' (three hundred feet) from the creek, I was required to dedicate and publicly record a 165-foot conservation easementlbuffer on both sides of the creek. A 15' buffer is considerably less than the 50 to 100 foot buffers that King County's own Code requires in rural areas. Further, within Renton city limits, Ordinance No. 5137 requires minimum 100-foot buffers for a class 2 stream. (Page 1025. a. I (a» Even by administrative reduction the minimum requirement is 75 feet. WHY ONLY 15 FOOT BUFFERS? Second question, will peak storm flow timing be altered post-project? Any alterations of upstream conditions in either the May Creek channel, wetlands, natural floodplain or any of the tributaries (i.e. Long Marsh Creek) may have significant adverse impacts on the tinling of peak flows through the valley, the canyon and the creek's mouth at Lake Washington. The relationslllp between flow, velocity and timing'of storm impulses and the role of the upstream May Valley wetlands and tributaries is not addressed in any of the county's reports or the design of this proposed project. The "May Creek Current and Future ConditionS Report" released in 1995 has an informative narrative and analysis of a storm event that occurred in1990. Tills analysis discusses the January 1990 storm and how the tributaries and valley wetlands influenced the timing of peak flows. (See pages 5-24 to 5- 30) The report states, "upper basin tributaries ... peaked long before the valley." While the storm was generally considered a 100-year storm, the storage and metering effect of May Valley reduced the flood flow at 148 th Ave SE (a.k.a Nile NE) andforther downstream to the range of a 10-to 25-year flow. "While the tributaries peaked in the morning of the 9th during the heaviest rainfall, the main stem of May Creek did not peak until some 8 to 14 hours later .... the large amount of valley floodplain storage resulted in a relatively small peak flow moving down through the valley at that time. A large portion of the flood volume was retained in the valley until the afternoon of the 9th, when floodwaters in May Valley began to recede .... The flood flow at 148 th equaled that ... of a 10-to -25 year flood .... TIlls spread out the time of peak or near-peak discharge in the canyon and at the mouth, rather than concentrating the flood volume with a consequent Illgher peak." (Page 5-26 MCC&FC Report) This begs the question, what are the post-project impacts on storm event timing relationships of May Creek, its tributaries, wetlands and floodplains and downstream erosion and flooding? lfwe are going to remove natural wetland/floodplain choke points (stormwater metering points) and/or "manage" sediment contributed by Long Marsh Creek, what will be the downstream impacts to storm flow intensity and timing? Conclusion, the downstream impacts of the storm (scary enough as they were in 1990) could have been much worse had the creek, tributaries and wetland not interacted as they did. Has the timing of flood events and flow rate post channel clearing/dredging been adequately addressed? Third question, what about erosion and destabilization of homes and hridges downstream? The threshold of sediment transport (i.e. erosion) affects the creek's banks (our property), infrastructure (homes and sole access bridges) and aquatic habitat. To support the proposed dredging project the county is relying, in part, on the May Creek Sediment Transport Study (KC 2010) and the Hydraulic and Hydrologic Analysis ofthe May Creek Channel Restoration Project. (KC 201 0) These studies use hydrologic simulation (HSP-F) and hydraulic model HEC-RAS. The number of data points in the Sediment Transport Study is limited because only three (3) flow-monitoring stations were established and one failed during the short 14-month study period. The County has attempted to make up for this lack of hard data by simulating hydrologic conditions. We are not comfortable with this as there have been acknowledged errors in previous modeling of May Creek. Further, as in most streams, all sediment is not created equal. There are different size particles in the various reaches of May Creek. Particle size sampling is required to validate any model or simulation. King County has many times acknowledged the downstream erosion and flooding problems. In 2007, the county hired the consulting firm of Anchor QEA, LLC to study sediment transport (erosion) and suggest ways to mitigate erosion and flooding of homes, bridges and properties. King County spent a great deal of money and staff time to work with the consultants to determine how to stabilize the banks of May Creek downstream of the proposed project. Ideas to reduce erosion and flooding of homes, loss of bridges, etc. included re-a1igning the creek channel, shoring up the banks and/or the outright purchase of at -risk -properties. The downstream challenges are significant. Yet, to-date, King County has not proceeded with any of this mitigation. Instead, they are proposing an upstream project that may exacerbate downstream risks! Between RM 3.8 and 4.0, the creek makes four 90-degree bends. At these bends, the creek banks are extremely unstable. Furthermore, over time the creek bed is arrnoring itself with larger and larger cobble thus flow is now impacting bank stability to a greater extend. The creek banks are eroding and migrating. This is not only imperiling at least one home but is most certainly causing loss of property and habitat through bank collapse. (This geomorphology was predicted in the "May Creek Sediment Transport Study". (See excerpt reproduced below [2]) We asked the county install more in-stream flow monitoring stations, gather more data and be absolutely certain that there will be no unintended negative consequences to downstream public and private properties, and stream habitat. On February 11th, 2011, King County Water and Land Resources (W&LR) completed the installation of six erosion-monitoring pins between River Mile 3.9 and RM 4.2 downstream of the proposed dredging project. Please note the stream bank erosion pins were installed on February 11,2011. These were set sticking one-tenth (l/lOth) ofa foot out of the stream bank per King County email reproduced here. "> From: Tim.Kelly@kingcounty.gov > To: klassicars@hotmail.com > Date: Man, 25 Apr 2011 12:12:57 -0700 > Subject: Emailing: Survey Notes for Andrew Duffus.pdf > > Hi Andrew, tried calling a few times but your number (425-255-xxxx) goes straight to a busy signal. I'll try and call again later today (and tomorrow if necessary), but if you get this just email me back so I know. The pins all look to be set around 0.1 '." At the bottom of this correspondence are stream flow records [(3) from October 1st , 2010 to April 8th , 2011. Notice the flow recorded on the second day of April 2011 -91.59 cubic feet per second. This writer examined three of the erosion monitoring pins on April 11th, 2011. Two of the pins were exposed over three-tenths (3/1 Oth) of a foot. This indicated over two-tenths (2/IOth) of a foot erosion between date of install and date of observation. The stream flow records at gauge site 37H show a maximum flow of 92 cubic feet per second between February 11th, 2011 and the observation date, April 11th. It is reasonable to conclude that erosion occurred at 92 cfs OR LESS!! In the past King County, or its consultants, have come up with various erosion thresholds. These theoretical thresholds have been determined by interpolation and modeling. The current estimate the county is using is 233 cubic feet per second. However, this estimate rests on a limited number of empirical observations. Recently we have seen with our own eyes that bank erosion has occurred at just 92 cfs or less. Through our lawyer, we have asked the county to delay this project until potential adverse impacts downstream can be evaluated. Now that the county has installed more stream flow gauges and erosion monitoring sites there is a wonderful opportunity to determine a refined erosion baseline and clearly document that this proposed channel dredging will not create any unintended negative consequences downstream. Fourth question, what about cumulative impacts of similar future proposed projects? The May Creek Channel Restoration Baseline Stream Conditions (KC April IS, 20 I 0) states, "The proposed project is one of four proposed "Ineffective Flow Projects" identified in the May Creek Drainage and Restoration Plan (GeoEngineers 2008). The four projects together would result in dredging of about 3.64 km (2.26 miles) of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length." (Page 1-4 MCCBRS(J The cumulative impacts o(all these projects must be addressed now! Not piecemeal as each subsequent project is considered. Fifth question, what about the ephemeral nature of this proposed project? GeoEngineers, the authors of the May Creek Drainage and Restoration Plan (GeoEngineers 2008) stated: "The greatest challenge and limitation to IPF 1 (Ineffective Flow Project One) is the ephemeral nature of the solution proposed. While IFP I would be expected to immediately address flood duration, conveyance, fish passage, and other issues, the benefits would be expected to be short lived .... May Valley is naturally a sediment deposition zone, and as sediment sources in the headwaters of the May Valley remain unmitigated, May Creek would be expected to fill back in." Before a lot of time, energy and money are spent, we ask that there is a concrete plan to address the otherwise ephemeral nature of the current proposal. MOREOVER, all the downstream impacts must be addressed! We are not saying that the project should not go forward. We are only saying that the county does not, at this time, have sufficient information to make this critical decision. We appreciate that the county has taken considerable time getting to this point. However, passage of time, by itself, does not fill in data gaps. As of today, data essential to making an informed decision is still missing. We ask that the City of Renton permitlvariance decision be deferred to allow time to collect the necessary data and correlate the rainfall, stream flows and erosion in real time. Until this year, there were no erosion monitoring stations in the reach oUlte creek that contains (our (4) erosion prone 90 degree bends. Until tlte (all 0(2009 there was no flow meter in this reach ofthe creek either. With these additional erosion monitoring stations pins and the additional flow gauge, it is now possible to have real time data to establish the erosion threshold with greater certainty. This, in turn, will allow the permitting agencies to understand better how the additional volume and velocity post-project may, or may not, exacerbate downstream flooding and erosion. We are asking for more time to collect and analyze data based on current known conditions (not assumption, interpretations or hypothesis). We are requesting greater certainty for the downstream citizens. We deserve mitigation to reduce any significant impacts to our homes, property and bridges and habitat. The city must not issue the permitlvariance until the Washington State Department of Ecology, other local state and federal agencies, tribes and the public (particularly the downstream property owners, all citizens of the City of Renton,) have had their questions and concerns adequately addressed by the applicant. Moreover, adequate mitigation be proposed downstream. The city has an obligation to look out for its citizen's best interests. This also applies to the public and private infrastructure and riparian habitat at the mouth of May Creek (i.e. Barbee Mills). In summary, our questions are threshold of sediment transport, cumulative impacts, timing of peak flows, the projects ephemeral nature and regulatory critical areas buffer widths. We are asking that your department review our concerns and ensure that the county's proposed project does not have any unintended negative consequences downstream within the City of Renton. As a downstream property owner, I request that the City of Renton defer the Special Permit for Grade/fill and Critical Areas Variance at this time. This will allow time to correlate rainfall data, stream flow and the recently established erosion monitoring pins. We must establish and better understand the actual threshold of erosion as it affects the downstream reach of May Creek. The proposed proj ect is primarily about draining several upstream horse pastures located in a wetland. There is potential for significant downstream impacts to people's homes and sole access private bridges! We ask Renton to consider this application very carefully and hold King County accountable. Sincerely, Andrew Duffus cc: Mayor's Office, City of Renton FOOTNOTES: (I) There are seven properties adjacent to May Creek within River Mile 4.3 an 4.9, the proposed project reach. One of these properties is a dedicated open space wetland; the second is an undeveloped-unused property that is obviously a wetland; and the third is not used for farming activity of any kind. The remaining four properties do pasture horses. None of the homes on these properties is in danger of flooding. Conversely. between Nile Avenue NE and Coal Creek Parkway there are 18 homes along the creek and two sole access bridges. At least eight of these homes are within 30 to 50 feet of the unstable creek banks and/or close enough to experience flooding (2) The armoring of the streambed and subsequent erosion of the banks was predicted in the "May Creek Sediment Transports Study", June 2009, Anchor QEA, LLC. Page 25 and 26 state the following: "The portion of May Creek examined in this study lacks an upstream sediment source for gravels and sands. As flow events impact the reach, the sediment size distribution along the channel bed will tend to coarsen over time; due to the transport of finer sediments out of the reach with no incoming sediment supply to replenish these materials. This armoring effect will tend to increase the threshold of sediment motion for the channel bed. On the other hand, bank sediments, which are likely of finer gradation than the bed sediments, will remain unchanged and are not affected by a natural armoring effect. Therefore, future erosion events may be characterized by bank migration (movement of the stream channel from its current location) as opposed to channel incising." Writer's comments: Bank migration equals risk and peril for homes and bridges. So we are draining horse pastures in wetlands to increase seasonal use, while we run the risk of exacerbating downstream conditions that put at peril not only sole access to properties (bridges), but the actual properties themselves and the homes that people, --not horses --LIVE IN! (3) Site 37H -May Creek at 143 PI SE Stream Gauge(Recording) Select a different water year: 12011 3~ :. l 3 4 5 6 7 8 9 10 ...... -Y" I WASHINGTON STATE Governor's Office of Regulatory Assistance FINAL Meeting Notes May Creek Channel Restoration Agency Meeting May 5,2010 Location Purpose Department of Ecology, NWRO, 3190 160·h Avenue SE, Bellevue, WA 98008 Review and comment on the May Creek proposal submitted by King County Water and Land Resource Division (King WLRD). Comments provided in the summary below were prepared by the Governor's Office of Regulatory Assistance (ORA) and are intended to offer a general overview of the infonnation presented during the meeting. Participating agency staff reviewed and provided comments for the Final Notes. Introduction King County Water and Land Resources Division (KC WLRD) presented a proposal for a channel restoration project in May Creek. The project description includes improving in-stream flow conditions and restoring a buffer of native riparian vegetation along segments of May Creek in May Valley between approximately river mile 4.3 and 4.9. The three primary components are: vegetation removal, sediment removal, and stream / wetland mitigation. Participants were provided the following information before the meeting primarily via the May Creek website (http://www.kingcountv.gov/environmentiwatersheds/cedar-river-lake-wa/may- creek.aspx): • State Environmental Policy Act (SEPA) Checklist and Mitigated Determination of Non- significance (April 21, 2010). • Wetland Delineation Report (March 2010). • Baseline Stream Conditions Report (April 2010). • Draft Hydraulics Report (April 20, 20 I 0). • Draft JARP A (Joint Aquatic Resources Permit Application) and project plans (Note: not available on website). The meeting began with a question and answer session regarding the project. The second half of the meeting was conducted as an agency round table to identify issues of concern, clarify requirements, offer suggestions how to avoid and minimize impacts, and describe permits and permit conditions. At the conclusion of the meeting, KC WLRD submitted application packets to the US Anny Corps of Engineers (Corps) and Ecology (ECY). Next Steps Identified during the meeting were three action items regarding the following topics: SEPA public comment period, reference materials, and a follow-up agency meeting. www.ora.wa.go~ .. ';6~~~;~;037 . 800-917-0043 [ assistance@ora.wa.gov T-······M·····a···y·····2·····5, 2010 · .. ··a WASHINGTON STATE Governor's Office of Regulatory Assistance ~ SEP A Public Comment Period ~ Several agencies (Muckleshoot Tribe at the meeting; WDFW, City of Renton, ECYafter the meeting) commented that it appeared their agencies did not receive a SEP A notice for the project. ~ A request was made to reopen or extend the comment period, which closed on May 5th . Next Steps: KC WLRD will review the situation with their SEPA staff and report back their fmdings to the group. ~ Follow-up from KC WLRD after the meeting: After reviewing our records. King County has confirmed, that due to an administrative error, the SEP A notification did not get sent to the necessary agencies per WAC 197-ll-3409(2)(d) for the May Creek Channel Restoration Project. Therefore, King County has not officially issued SEPAfor this project. King County will be issuing SEPAfor this project within the next 4 to 6 weeks. We are delaying the issuance to allow time to consider modifying the project description based on the feedback received at the May 5, 2010 meeting. We are sorry for any inconvenience that this may have caused and thank you for your ongoing assistance with this project. ~ Reference Material(sl for Earlier Projects on May Creek. ~ A previous sediment removal project was conducted near the McFarland property in 2002. This was a small, pilot project by KC WLRD. ~ A planting project on the Colassurdo property was implemented in the fall of 1995. Next Steps: KC WLRD will review their files and forward information to the group regarding these two projects. The planting plan from circa 1995 may no longer be available in King County archives. King County is searching through their files to see if project files are still available. Next Steps: Agency staff participating in the meeting will review files to determine if they have information on these projects to share with the group. If they find relevant information, please distribute to the group. ORA can also assist with distribution. ~ Agency meeting. ~ The Corps offered to review the proposal and offer design suggestions to reduced impacts on the aquatic environment. The Corps invited other agencies and tribes to participate in the review and comment process. The .outcome could result in a substantial redesign to facilitate review under the standard Individual Permit (IP). Or suggestion for activities such simply planting in the buffer which would have a shorter review, potentially under a Nationwide Permit (NWP) 27. ECY would need to verifY the wetland delineation. www.ora.wa.gov 360-407-7037' 800-917-0043 i assistance@0ra.wa.gov May 25. 20;;--11 --- WASHINGTON STATE Governor's Office of Regulatory Assistance· Meeting and suggestions could be provided within a 30-60 day window. (Note: this assumes staff availability within 30-60 days.) KC WLRD suggested that the technical experts who worked on the various reports (wetland, stream, and hydraulics studies) be available to answer questions for agency staff. Next Steps: KC WLRD will discuss to detennine if this is an approach they would . like the agencies to pursue. If yes, KC WLRD will coordinate with the Corps. Agency Comments King COUJity Department of Development and Environmental Services (King DDES) Two pennit processes are possible for the project: Grading pennit as allowed alteration under the Critical Areas Code if considered Habitat Enhancement OR Grading pennit with a separate Alteration Exception I Reasonable Use Exception of Critical Area Code if not considered habitat enhancement. .. Habitat Enhancement Project ~ After reviewing proposal, King DDES anticipates it would be able to permit the project under this approach. ~ Requirements: Demonstrate that project restores habitat fonning processes or directly restores habitat function and value. Restoration and enhancement plans must be prepared by a qualified biologist OR all properties have an approved King County Farm Management Plan (approved by KingDDES). Average review time 120 days after submittal ofa complete application. .. Alteration Exception ~ Includes a public comment process. ~ Requires an alternative analysis, similar to the Corps 404(bXl) analysis, to ensure minimal impacts. ~ Appealable decision. ~ Average processing time 4-6 months after submittal of complete application. -7 In general, this process is usually longer and more expensive for the applicant. WASHINGTON STATE Governor's Office of Regulatory Assistance ~ Other Comments. 7 If the Corps requires a standard Individual Permit (lP), King DDES would require the Alteration Exception process. Much of the information the Corps would request of KC WLRD for the lP process would likely be similar to what King DDES would need to generate for the Alteration Exception application. 7 Buffers: no specific distance required to qualify for a habitat restoration· process. The buffers must provide an improvement over existing conditions. Acceptable buffer widths vary by project. Mayor may not accept buffer widths in Farm Management Plans by the King Conservation District. Right now, most of May Creek does not have any effective buffers. King DDES would see planting buffers with appropriate native vegetation as an improvement to the existing conditions. Buffer plantings would need to be fenced. Overall, King DDES needs to see an improvement or net gain. King Conservation District (KCD) ~ Two properties in project area currently have Farm Management Plans. ~ Existing Farm Management Plans in project area generally try to achieve 25 ft buffers on average for pasture areas. However, one property has a fence that is grandfathered in at 15 ft as it was installed prior to 1990 (the Celigoy property). KCD generally promotes installing larger buffers but it doesn't work all the time. ~ Farm Management Plans are landowner driven. ~ Prepared under National Resource Conservation Service (NRCS) methodology. Plans are not public documents. However, property owners may grant permission to release the plan to specified individuals. ~ Some of the farm land in the May Valley has recently gone through ownership changes . . Many of the new owners are interested in implementing Farm Management Plans. Implementing Plans often involves relationship building between the landowner and KCD. Renton ~ For the work within Renton City limits, project would most likely require: 7 Grading and Fill permit. 7 Critical Area Ordinance (CAO) Permit. Review will be required to determine if project qualifies for an exemption or needs a variance. 7 Construction permit. Land Use Examiner process used for Grading/Fill permit. Both the Grading/Fill and CAO process require a public hearing. ~ Average time 8-10 weeks, assuming no appeals. www.ora.wa.gov ._---------------------- I WASHINGTON STATE Governor's Office of Regulatory Assistance ~ If project has only 280 cubic yards of fill, then an Annual Grading License may be another option. ~ Renton offers a pre-application meeting to discuss the details and clarifY requirements. U.S. Army Corps of Engineers (Corps) ~ Corps considers the purpose and need for the project when determining which permit is appropriate. ~ As proposed, the purpose of the project appears to be "flood control" or "increased conveyance" with some habitat features incorporated in the design for mitigation. ~ The current proposal appears to contradict some of the recommendations for improving stream habitat and functions as presented in the Baseline Stream Conditions Report. ~ The project as proposed does not meet the terms and conditions ofa NWP 27. ~ At this time, project appears it will require a standard Individual Permit (lP) where a range of off-and on-site alternatives will be considered. The off-site alternatives will likely address source control and sustainability of any proposed action. On-site alternatives will evaluate ways in which impacts to the aquatic environment could be reduced. ~ A 404(b)(l) Alternatives Analysis required for an lP. Different evaluation than is required under SEP A. Considers alternative with least impact to aquatic resources. ~ Public Notice period part of process. ~ Endangered Species Act (ESA) consultation required. ~ Cultural Resources Survey also required. ~ Threshold for an lP vs. an NWP is based on the ecosystem restoration. The values and functions of the stream are considered. ~ For example, a NWP 27 would consider sediment removal when the purpose is for improved habitat functions. ~ Timelines: (Note: "average" assumes straight-forward project review without significant issues / concerns and project revisions.) ~ lP: 180 days to 1 year average based on submittal of a complete application. ~ NWP: usually shorter than for an lP but still 4-6 months on average. ESA and Cultural Resources still required for NWP. ~ The ESA process for all projects has been averaging 71 days. MuckIeshoot Tribe ~ Note: Some of the Corps permits processes include consultation with the Tribes. This is the case with the Corps lP. ~ The project needs to provide details about the proposed mitigation; how does the mitigation compensate for the amount of dredging? The details for the proposed wood are missing, www.ora.wa.gov 360-407-;~37 . 800-917-0043 '] assistance@ora.wa.gov May 25.201011 WASHINGTON STATE Governor's Office of Regulatory Assistance --------- including the sizes, numbers, and species. The project will result in a loss of rearing habitat (albeit due to reed canary grass) and will need mitigation. A 15 ft buffer is insufficient. There needs to be fencing and long term protection of the buffer. ~ The Muckleshoot Tribe will review how much mitigation is included and what is sufficient. ~ Reed canary grass: even though a non-native species, provides juvenile salmon rearing . habitat particularly because it provides lower water velocities. ~ Mitigation and riparian buffer proposed for the project (15 ft) may not be adequate because it does not appear to fully mitigate the project impacts. ~ More information to evaluate impacts would be required. -> Concerned about long term, repeated sedimentation and subsequent removal projects. One of the project reports mentioned three other sediment removal projects for a total of2.6 miles of May Creek. Need more information if this is the case. Cumulative impact from'more dredging on this reach of the stream as well as other locations is a concern. -> Also, questions about how removing sediment from May Valley will impact downstream flow, erosion, and fish habitat. WA Department of Fisb and Wildlife (WDFW) ~ Project needs to demonstrate no net loss of habitat. ~ Planting plan required. Crucial for long term prevention of reed canary grass proliferation, which increases sediment continuing to accumulate in stream. ~ The wider the buffer width on the stream, the better. WDFW does not have specific buffer requirements. However, WDFW has buffer recommendation in Management Recommendation for WA Priority Habitats, Riparian (f1ttp://wdfw. wa. gov/hab/ripxsum.htmJ. ~ Stream Report, page 8 and II. Gravel from Long Marsh Creek is an important spawning habitat. Do not want to see gravel in this area of May Creek disturbed. Would be better to widen this area where Long Marsh Creek flows into May Creek. ~ Not meaning to speak for the Corps, but in trying to qualify for a NWP, it is recommended to design the project without a flat channel profile hy adding pools and large woody material. ~ Note: the WDFW application cannot accept a Hydraulic Project Approval (HP A) application until the SEP A process is complete. Ecology 401/ Coastal Zone Management (CZM) ~ The 40 I Certification status depends in part on what permit the Corps determines is appropriate for the project. -> If project is a NWP, then a 401 mayor may not be required. -> If IP from the Corps, then ECY will require an Individual 401 and a CZM Consistency Determination. WASHINGTON STATE Governor's Office of Regulatory Assistance ~ Individual 401 and ClM must be completed before Corps can issue IP. ~ Other comments: -7 Project needs to follow current ECY Stormwater Management Manual for Western Washington. -7 If greater than I acre disturbed, ECY Construction Stormwater General Permit required. -7 Since the mitigation report is pending, not able to review in full at this time. Ecology Wetlands ~ Concerned about several inconsistencies between Baseline Stream Conditions Report and the proposal. For example: ~ The purpose of the project appears to be to provide stormwater conveyance rather than habitat restoration. -7 From ECY perspective, concerned that project will not meet goal to drain water from pastures such that pastures will be dry earlier in the year. The high groundwater table in many of the pasture areas will keep the pastures wet. -7 At this point, ECY may not be able to approve application as proposed. -7 Concerned that adequate buffer widths have not been proposed based on Best Available Science (BAS). Proposed buffers for wetlands and the stream may not be effective. Ecology Water Quality (ECY WQ) ~. May Creek is on the state 303(d) list for Fecal Coliform. ~ Most of the sampling and data is from King County. ~ Because of this, ECY would like to see limiting of animal access to May Creek. ~ ECY WQ staff prefers 35 foot buffers. The proposed IS foot buffers appear thin for preventing future sedimentation of the Creek. ~ ECY WQ staff prefers South side buffer to be wider than 15 feet since it provides the best shading which helps reduce summer temperatures in the Creek. ~ Stream morphology, such as a meandermg stream, provides benefits of reducing sedimentation and improving water quality. Realize there are limitations with private ownership and that this might counter the water conveyance objectives of the project. Channel meander might be considered for the improvements in the area south of 148"'. ---_._--------------------- WASHINGTON STATE Governor's Office of Regulatory Assistance Attendees (per sign-in sheet) ~ Zelma Zieman, ORA . ~ J ane Dewel~ ORA ~ Doug Chin, KC WLRD ~ Rachel Berryessa, KC WLRD ~ Don Althauser, KC WLRD ~ Curt Crawford, KC WLRD ~ Lindsey Miller, KC WLRD ~ Randy Sandin, King DDES ~ Jamie Hartley, King DDES ~ Karen Walter, Muckleshoot Indian Tribe Fisheries ~ Larry Fisher, WDFW ~ Jay Mirro, KCD ~ Jennifer Henning, Renton ~ Ron Straka, Renton ~ Lori Lull, Corps ~ Matt Bennett, Corps ~ Rebekah Padgett, ECY 40 JlCZM ~ Paul Anderson, ECY Wetlands ~ Patrick McGraner, ECY Wetlands ~ Dave Garland, ECY WQ ~ Chris Coffm, ECY WQ www.ora.wa.goy 360-407.7037' 800.917~~;·· [ assistance@ora.wa.gov . I" MaY;~.201~ .....• ------- > • " ~" 1-> ,. .... • ~ . ~ I -l' ,. r , • -. • f ~ • ~ J. ~ -.. ..: ).. . ; ij .' . . • .. ~' .~ .' ....... -. • • • 'f "I' .. e' , .. .~ ~ r t " , . • _ • o- f:-f· ,H , I • • • I~ I t , , I ) .'. . '4 i , ,. I . , i • ,. ,,-.,------------------------ -v, Gerald Wasser From: Sent: ,. To: Subject: Attachments: Helio, A DUFFUS [klassicars@hotmail.com] Wednesday, September 14, 2011 3:16 PM Gerald Wasser May Creek Dredging EcyOlsonquestions.pdf; Ecy1oKC9111.pdf EXHIBIT 15 Attached is a recent memo from Dr. Patricia Olson of Washington State Department of Ecology. She questions the county's proposal to dredge a section of May Creek Also, attached is a formal letter from Ecology regarding the county's application for a Section 401 Water Quality Certificate and determination of Coastal Zone Management Consistency. These validate downstream property owners' concerns. Thanks for your support. Andrew Duffus 1 ~---------------------------------------------------------------------- Memo Page 1 To: Rebekah Padgett, 401 Coordinator, SEA-NWRO From: Patricia I.. Olson, Senior Hydrogeologist, PhD, LHG, SEA-HQ cc: Patrick McGraner, Erik Stockdale Date: August 15, 2011 Re: Comments on Upper May Creek dredging project My comments are mostly based on observations from our field visit on 07/29/2011 supplemented by technical documents provided by King County. I also reviewed comments from USCOE, Muckleshoot Tribe, and downstream.property owners but did not include in my discUssions. I have many comments on the King County documents. But I have limited time so this memo contains only a summary of some important issues. 401 certification and WQ issues The King County memo from Julia Tumey to Doug Chen dated 2/11/2011 discusses how the project will increase the channels fine sediment transport efficiency within the project area (pp 14). The memo also states that fine sediment and organic material will be transported downstream at a constant rate rather than an episodic rate (pp 15) and sediment delivery to May Creek will be reduced "in the project area". This will be a change in the current sediment transport regime and current downstream effects from the fine sediment transport Since lower flows will be transporting sediment, the fine sediment will likely be deposited in areas upstream of where high, episodic flows would deposit the sediment However, the memo does not address what sediment volumes will be transported and where fine sediment will be deposited downstream other than to say it won't be Lake Washington. While the memo says that the project will decrease the agricultural sediment source at some time in the future, it does not say how long the increased sediment load will occur. The memo states that quantitative sediment estimates are not available (pp 16). These factors present ambiguities in terms of water quality effects. Dredging The project seems somewhat short-sighted because one time dredging will not solve the flooding extent and duration over time. LiDAR data indicate that there are large floodplain areas below the channel elevation (Figure 1). Some of this is may be due to LiDAR processing for the bare earth DEM. However, the Hand H study supports this conclusion (pp 19). The "flood basin" type landform may be a natural condition or it may be due to years of dredging and lowering groundwater levels which promotes subsidence in organic rich soils (e.g. hydric and peat soils). Wetland drainage leads to oxidation of the upper organic horizon burning up organic component The weight of livestock and machinery will increase the compaction and subsidence as well (e.g. Devin and others 1999). The survey notes that accompany the General Land Office (GLO) maps shown in the Tumey memo indicate that the upper basin was mostly a groundwater fed wetland system. These conditions suggest that dredging is somewhat akin to trying to channelize a bathtub where water inflow is greater than outflow. . . -------------------_ ... Cost-benefit: There may be a cost-benefit analysis but I haven't found it There should be cost-benefit analysis of various options including removing backwater effects caused by bridges, reducing reed canary grass, reducing or eliminating fine sediment sources, and removing willows and replanting with vegetation that was documented to occur in the area including cottonwood, ash, maple, cedar and undergrowth species such as alder, native Pacific crabapple (Malus Fusca), and vine maple. Backwater effects Backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge. The FEMA longitudinal profile indicates that backwater likely occurs at floods less than the 10-year flood. The King County Hydraulic and Hydrologic, Ana!JIses of the May Creek, Channel Restoration Project, 12/17/2010 (hereafter referred to as the Hand H study) includes measured water surface profiles that include the footbridge. Table 1, pp 4-5 shows the footbridge location as river mile 4.612. Figure 3, pp 19 shows the water surface elevations measured on 01/08/2009 and 01/22/2009. The measured water surface profiles just upstream of the bridge show the backwater effect However, the documents ignore this effect For example, on pp 31, of the Hand H study, a description of gravel bar and flooding is given: "During mean annual flows (8.6 cfs through the study area), control points are vegetation choking points in the wetland downstream of 148th Ave SE bridge and mildly so upstream of 148th and gravel deposition where Long Marsh enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04. Similarly for higher flows (e.g. 1 year event), Long Marsh again controls water surfaces upstream for the same reach length." Again on pp 54: "These results are also dependant on the relocation of where Long Marsh creek deposits gravels during storm events. This tributary has clearly been shown in the past to deposit enough gravels to effectively backwater May Creek upstream of its confluence. Additionally, shear stresses in May Creek are far below forces necessary to mobilize gravels that are being deposited by Long Marsh creek." Well, shear stresses generally are lower in backwater areas. We visited this site, and the form and location of the gravel bar strongly suggests that the bridge is causing the excess gravel deposition probably due to the back water effect Therefore the bridge is the primary cause of the deposition and backwater effect extending 2000 feet upstream (from H and H study). The gravel would disburse downstream rather than creating an oversized gravel bar if the bridge were sized properly or removed during overbank flows. Instead of evaluating this option, the documents focus on removing the gravel and "mitigating" by removing the existing vegetation buffer along Long Marsh Creek and forcing the Creek into an unnatural planform. The documents acknowledge that the 148"' Street Bridge causes a backwater effect This effect can be seen of the FEMA longitudinal flood profiles. While the effect is more local resizing the bridge would also increase hydraulic efficiency just upstream of the bridge. The Long Marsh Creek mitigation project is not mitigation. The proposed stream alignment does not appear to be based on the existing or historic channel characteristics. The LiDAR data shows an alluvial fan but it indicates that there were distributary channels rather than a single channel meandering stream (Figure 1). A similar situation occurs on the Indian Meadows alluvial fan. The proposed planform and the area allotted for channel movement is not natural to an alluvial fan • Page 2 system so is not a restoration project but more of a drainage efficiency project not related to historic fluvial processes and landforms. Geomorphic analysis The geomorphic interpretations and sediment transport study appear to be done by persons not well-versed in fluvial geomorphology and channel response. For example, the Sediment transport study conducted in the ravine (Anchor QEA, LLC, 06/2009) relies on pebble counts along 3 transects for evaluating sediment transport Pebble counts tend to be biased towards larger sediment This bias means that the median sediment size, for example, could be larger than it really is resulting in higher discharge estimate to mobilize bedload. This may explain why the calculated effective sediment mobilization discharges are between the s-10-year floods. In boulder areas this makes more sense. However, the sediment I saw in the near the Duffus and downstream properties is much smaller and should be mobilized at a lower discharge. The lower end· of the range (73-150 cfs) estimated in the Hand H study appears more realistic for the areas we observed. Moreover, for sediment transport, pebble counts should be done primarily on bars not the channel. The sediment transport study appears to have only reliecj on cross-channel pebble counts. Plus, a statement is made that the channel maybe armored. Channels with pavement or armoring should include a subsurface pebble count (e.g., Buffington and Montgomery 1997, 1999). As pointed out in the documents, HEC-RAS sediment transport model cannot address variable sediment transport conditions and changing channel elevations (erosion or deposition). Pebble counts may work for reconnaissance level study on the site basis (but not the whole reach), but not for a study related to assessing potential hazards such as damage to structures. Volumetric sediment sampling and more sample locations would be more appropriate in this case King County's Department of Natural Resources, Water and Land Resources Division have well qualified fluvial geomorphologists and geologists. The proponents of this project and the geomorphologists and geologists are in the same division. However, these qualified people appear to not have been consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomorphic processes that created the current conditions, and downstream channel response including migration to changes in flow and sediment regimes. The expertise is available within the same King County department and division. These people should be consulted on this project Downstream bank erosion. Since the sediment transport study and the Hand H study appear to rely on reconnaissance site level data that does not include adequate sampling points, I cannot make a determination concerning potential for increased bank erosion downstream of the project area. There are many factors affecting bank erosion in the downstream reach such as riprap focusing flow against unprotected banks, reduction in natural sediment source from bank erosion, and head cutting from response to glacial lowering of the base level and more recent lowering of base level when Lake Washington water levels were lowered for transportation purposes. However, I disagree with the statement made in the Hand H study that the increase in frequency of smaller floods is insignificant While it may be the case, this hypotheSiS has not been tested using adequate data. This conclusion wouldn't be an issue if there were not structures downstream, but there are. The Hand H study indicates thatthe project will increase the frequency of occurrence for smaller floods (Table 8, pp 47-48). For example, the 1.01 year flood • Page 3 (67 cfs) and 1.11 year flood (118 cfs) frequency of occurrence will increase by 16% and 10% respectively. The 2-year event, often considered a surrogate for effective discharge where data are not available, frequency will increase by 5%. The increase in frequency of these small floods could affect sediment transport dynamics. Simply put, the increase in small flood frequency will increase the occurrence of unit stream power (specific weight of water' channel gradient' discharge/active channefwidth) associated with these small floods by 16, 10 and 5%, unless gradient decreases or width increases. Since gradient is somewhat controlled by valley conditions, stream width is more likely to change. Stream power is an indicator of transport capacity. Increased transport capacity can lead to increased incision and bank erosion. Yet the Hand H study says there will be no significant effect. There appears to be a disconnection in the conclusions supporting dredging. A 5-16% increase in stream power for potential sediment transport events is not significant but a 0.04% decrease in flooding duration of 50 cfs is significant enough to dredge (Table 9, pp 53, Hand H study). Since there is disagreement between sediment transport numbers, King County should use its geologic and geomorphic expertise and further evaluate adding sampling points and designing an appropriate sediment transport and erosion study. Also the existing transport modeling should have independent review because not all sediment transport models apply everywhere. In the meantime King County and residents should explore other options such as increasing conveyance capacity under 148<h Street Bridge and footbridge just downstream of Long Marsh Creek. The foot bridge is obviously an imposition on water conveyance as the sediment wedge developed upstream testifies. The King County documents indicate that flood storage will be reduced in the project area, so additional flood storage to compensate for that loss should be included in the project. The GLO survey notes describe upper May Creek from just downstream of the Renton-Issaquah Road and upstream as a crabapple swale. Vegetation consisted of Pacific crabapple, hardhack, willow and some indiscernible tea. There was no mention of any 'brook" or other flowing water feature. The vegetation and lack of surface water implies it was a groundwater fed wetland. Restoration of some wetland functions in the project area as well as this area could increase flood storage and attenuate flood volumes downstream. Other options include, reducing reed canary grass, reducing or eliminating fine sediment sources (those above background), and replanting vegetation that was documented to occur in the area including cottonwood, ash, maple, cedar and undergrowth species such as alder, native Pacific crabapple (Malus fusca), and vine maple . • Page 4 Page 5 References Buffington, j.M., and Montgomery, D.R 1997. A systematic analysis of eight decades of incipient motion studies, with special reference to gravel-bedded rivers. Water Resour. Res. 33: 1993-2029. Buffington, j.M., and Montgomery, D.R 1999. Effects of sediment supply on surface textures of gravel-bed rivers. Water Resour. Res. 35: 3523-3530 Galloway, Devin, David R jones, and S.E. Ingebritse, eds. 1999, Land Subsidence in the United States U.S. Geological Survey Circular 1182. Page 6 Figure 1: A relative water surface elevation DEM was derived from the LiDAR bare earth OEM. The OEM shows t he relative height of land surface in relation to water surface (in feet) at the time of the LiDAR flight The blue values indicate areas that are below the water surface elevation. --DIstributary-traces --Upper_MaLcr1I:_stream Up_may_rws9 <VALUE> ,E-Hl--7,5 _-1.49--7 WFifi1 ~.99 --6.5 ~'U9--6 !!a?lt4l1-5.99 --5.5 lillIWl-s.49 --5 1,7' '14,99 -4,5 1.-"·'1",,49-4 roo, ·:1-3.99 --3.5 1,"'·1-3A9--3 1:;'1"1-2,99 --2.5 D-2A9--2 0-1.99--1.5 0-1.49--1 o -0,99 --0,5 0-0·499-0 00,001-0.5 00,501-1 01.01-1,5 01.51-2 02.01-2.5 02.51-3 0 3.01-3.5 0 3.51 -4 04.01-4.5 04.51-5 05,01-5,5 05,51-6 06,01-6,5 0 6,51-7 0 7,01-7.5 07,51-8 0 8.01-8.5 0 8.5 1-9 09,01-0.5 00.51-10 0,0.1-,0,5 010.6-11 p.:~, 111.1-11.5 1"",;ellL6 -12 h~ ···'1 12.1 -12.5 1,·+", 12,6 -13 1::;;-.·-.113.1 -13.5 b.': :-..113.6-14 I:;,:;, 114.1 -14.5 .,4.6-15 STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office' 3190 160th Avenue Sf· Bel/evue, Washington 98008·5452 • (425) 649·7000 September 1, 2011 Doug Chin, Project Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 RE: U.S. Army Corps of Engineers (Corps) Reference #NWS-2010-1S8 Status of Application for Section 401 Water Quality Certification and Coastal Zone Management Consistency for the May Creek Drainage Improvement Project, Renton, King Coup.ry, Washington Dear Mr. Chin: The U.S. Army Corps of Engineers (COlpS) issued a joint public notice with the Department of Ecology (Ecology) for the above project on September 24,2010. Ecology has one year to issue its individual Section 401 Water Quality Certification (WQC). On August 31, 2010, Ecology notified you by certified letter that this project would require an individual WQC and Coastal Zone Management Consistency (CZM) determination and requested additional information. Throughout the review of this project, Ecology has raised a number of questions about the purpose and need of the project, as well as technical issues regarding the wetlands, sediment tI1j11SpOlt, and water quality (see Attachment 1). As the statutory deadline of September 23,2011 apProaches, we are concerned that many of these issues have yet to be fully addressed and we will not have reasonable assurance that water quality standards will be met. In order to complete the WQC process and make our CZM determination; we need the following additional information: .. • Description of how the sediment disposal areas will be stabilized in order to prevent fine material from entering waters of the state (including wetlands). • Construction Water Quality Protection and Monitoring Plan (King County, July 2011): o Page 1, Section 2: The citation for the section of the water quality standards that allows a temporary area of mixing for turbidity during construction should be cOrrected from WAC 173-201A-400 (4) and (6) should be corrected to WAC 173- 201A-200(I)(e)(i). ----------------------_ ... ----------_ ... Doug Chin, Project Manager September 1,2011 Page 2 of6 o Page 2, Section 3, Sampling Locations: Ecology agrees that the background and point of compliance sampling locations will need to change as the project moves from segment to segment. And it is understood that Figure 1 is a representative site plan showing sampling locations. Please note that background samples should be taken at the same time as the point of compliance samples. o Page 4, Section 3, Long-term Data Storage and Reporting: The plan illdicates that data will be provided to regulatory agencies upon request. The plan should be. updated to reflect that if no exceedances are detected results of water quality sampling should be sent to my attention at Ecology on a monthly basis and that any exceedances should be reported within 24 hours with the following information: a. A description of the nature and cause of exceedance. b. The period of non-compliance, including exact dates, duration, and times and/or the anticipated time when the Applicant will return to compliance .. c. The steps taken, or to be taken, to reduce, eliminate, and prevent recurrence Df the nDn-compliance. d. In addition, within five (5) days after notification of an exceedance, submit a written report that describes the nature of the exceedance, turbidity results and location, photographs, and any other pertinent information. • It is expected that there will be stream water temperature changes between the time the CDunty removes more mature vegetation and when the replanted vegetation reaches the size to shade the creek, creating an additional impact to water quality. What measures will be taktm to address this? • The May Creek Drainage Improvement Project (9AI205) King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan, prepared by King County Road Services Division, revised July 2011, needs to be revised to: o Vegetative coverage of 80 percent under Section 6.1, o Replanting of dead plants to 100 percent for· years I and 2 under Section 6.1, and o Include submittal of an As-Built Report and monitoring reports for years I and 2 under Section 6.2, Post-Construction Monitoring, • The memorandum from Julia Turney to Doug Chin, King County, RE: May Creek Drainage Improvement Project: SE May Valley Road 148 th Avenue SE-Sedim~nt Assessment, dated Febluary 9, 2011, does not address what sediment vDlumes will be transported and where fine sediment will be deposited downstream other than to say it will not be Lake Washington. While the memDrandum states that the project wi.ll decrease the agricultural sediment source at some time in the future, it does not say how long the increased sediment load will occur. The memorandum states that quantitative sediment estimates are not available (page 16). Doug Chin, Project Manager September 1, 2011 Page 3 of6 King County developed a plan to monitor for erosion downstream from the project area (memorandum from Don Althauser, King County, to Bill Kerschke and Julia Turney, King County, RE: May Creek Drainage Improvement Project (9A120S) Post- Construction Erosion Monitoring Plan -Downstream of 148th Avenue SE, dated August 4,2011). The plan needs to be revised to include the project area. The sediment monitoring plan should monitor sediment accumulation or erosion in the creek and changes in channel cross-sections and longitudinal profile to provide information on project effectiveness. It also should include contingencies in case the project does not perform as' expeCted. • The revised JARP A #6a, StreamlWetland Mitigation, first bullet, states that fencing will be installed around the planting areas to minimize livestock access to the stream. This appears to refer to the riparian planting buffer on both sides of May Creek-is this correct? Current site plans show fencing around the mitigation area west of I 48 th Avenue SE, however the plans are do not show fencing that would permanently exclude livestock from direct access to the restored riparian planting buffer area and. creek upstream of 148th Avenue SE. The plans should be updated to reflect this. • #6d of the JARP A refers to a riparian planting buffer along Long Marsh Creek. Will the buffer be on both sides of the creek? How wide will the buffer be? Will there be a buffer along the new side channel, and if so, how wide will this buffer be? Are the riparian buffer areas along Long Marsh Creek and the side channel included in the proposed mitigation calculations-Ecology does not believe that this should be included. • #6d of the JARPA mentions that 16 pieces oflarge woody debris will be placed in the off-channel alcoves. Does this figure iriclude the snags? And is it correct that another 60 pieces of large woody debris will be placed in the wetland enhancement area per the JARP A? These figUres are inconsistent with the May Creek Drainage Improvement Project (9A1205) King County Water and Land Resources Division Stream and Wetland Impact AnalYSis and Mitigation Plan, prepared by King County Road Services Division, revised July 2011, page 4, first bullet, which states that 76 pieces oflarge woody debris and 2 snags will be installed. These figures need to be clarified. • In King County's July 22, 2011 response to May II, 2011 comments by Karen Walter, . Muckleshoot Indian Tribe (page 3), the County mentions a Draft Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report and says that the final report will be available upon request. Please provide a copy of this report to Ecology. • On September 16,2010, Ecology noted concem about the IS-foot riparian vegetation buffer in comments on the State Environmental Policy Act Mitigated Determination of Non-Significance (MDNS). Specifically, we questioned the effectiveness of this size buffer in shading out reed canary grass and stated that we could not support the proposed Doug Chin, Project Manager September I, 2011 Page 4 of6 project with this size buffer. The proposed IS-foot buffers remain below the best available science which would more closely approximate 30-35 feet. As Karen Walter of the Muckleshootlndian Tribe has pointed out (May 11, 2011 comment letter to Ecology), King County Code requires existing livestock operations to , implement a farm management plan or meet management standards outlined in the Code. In King County's July 22, 2011 response to Ms. Walter, you indicate that two of the four livestock operations have developed plans and that the buffers specified in these plans are 25 feet-l 0 feet more than the County is proposing. • In Ecology's comments on the MDNS we also noted that the proposed planting of the "buffer" particularly on the left bank in Reach 4 is problematic because this area is NOT , buffer. It is wetland that likely receives runoff from upslope seepage as well as bank oveltopping. TIlls area is very wet and needs to be planted with native vegetation that can tolerate long periods of inundation. Concerns remain with regards to plant establishment in wetter reaches, specifically on the left bank upstream of Long Marsh Creek. Site plans are not specific as to which plants will be installed in this reach. • It is Ecology's assessment that backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge, extending 2,000 feet upstream. The form and location of the gravel bar indicates that the bridge is the prim81Y cause for excess gravel deposition probably due to the backwater effect. Therefore, it appears that the bridge, rather than the gravel bar, is the primary cause of the deposition'and backwater effect extending 2,000 feet upstream. The report focuses on dredging and vegetation removal, without considering resizing or removal of the bridge. Additionally, the documents' acknowledge that the 14Sth Avenue SE Bridge causes a backwater effect. Resizing the 14Sth Avenue SE bridge would increase hydraulic efficiency just upstrerun of the bridge. King County and residents should explore other options such as increasing conveyance capacity under the 148th Avenue SE bridge and the footbridge just downstream of Long Marsh Creek. • Ecology believes that the effectiveness of the proposed action for the stated intent of decreasing the duration of surface water on the grazed wetlands: o Has not been fully demonstrated to merit the level of impacts proposed for 0.04% decrease in flooding duration of 50 cubic feet per second (cfs), and o' One-time dredging will not solve the flooding extent and duration over time because large floodplain areas lie below the channel elevation; water inflow into the wetland system appears to be greater than the outflow; no upstream sediment study has been provided with detailed plans to reduce upstream sediment; changes to the 1.48th Ave SE bridge and footbridge downstream of Long Marsh Creek have not been proposed to increase conveyance capacity. • King County's Department of Natural Resources, Water and Land Resources Division has well qualified fluvial geomorphologists and geologists on staff; however, it does not Doug Chin, Project Manager September 1, 2011 Page 5 of6 appear that they were consulted for evaluating the sediment transport study, baseline geology and hiStoric channel form and geomorphic processes that created the current conditions, the doWnstream channel response including migration to changes in flow and sediment regimes. The studies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data. King County should utilize its geologic and geomorphic expertise and further evaluate adding sampling points and designing an appropriate sediment transport and erosion . study. Additionally, the existing transport modeling should have independent review because not all sediment transport models apply everywhere. Ecology questions the premise upon which the proposal is based and cannot complete its review Until this work is complete and the County has reassessed the project. Unless we receive all ofthe above documentation by September 16, 2011. Ecology will have to deny the WOc/CZM for this project. Receipt of a denial without prejudice does not preclude you from resubmitting a request for 4~1 Certification at a later date. Please contact me if you have any questions regarding this letter or the 40l/CZM Certification process at (425) 649-7129 or e-mail atRebekah.Padgett@ecy.wa.gov. Sincerely, tl(~ Federal Permit Manager Shorelands and Enviromnental Assistance Program RRP:cja By certified mail #7011 0470 0003 37208964 Cc: TJ Stetz, U,s. Army Corps of Engineers Lori Lull, U.S. Army Corps of Engineers E-Cc: Patrick McGraner, Ecology Patricia Olson, Ecology Erik Stockdale, Ecology Loree Randall, Ecology Doug Chin, Project Manager September I, 2011 Page 6 of'6 3/24/10 5/5/10 9116/10 4/26/11 4/28/11 Attachment 1: May Creek Key Ecology Correspondence Chronology Ecology raised concerns in an e-mail that followed up on a 2122/10 site visit,· including the effectiveness, purpose, and need of the project, as well as the effectiveness of the IS-foot-wide buffers. Ecology pru.ticipated in an interagency pre-application meeting where. we provided substantive comments regarding the effectiveness, purpose, and need of the project, as well as the need to redelineate the wetland, buffer width, and livestock access to the creek. Ecology submitted comments on the State Environmental Policy Act mitigated determination of non-significance regarding effectiveness, purpose, and need of the proposal, buffer width, how wet the left bank is in Reach 4 for establishing canopy cover, the degradation of the pastures and need for farm plans to protect riparian habitat and creeks, and livestock access to the creek. Ecology participated in an interagency site visit where we raised questions about the effectiveness, purpose, and need of the project, permanent protection of the mitigation area, the buffers on Long Marsh Creek, whether the Long Marsh Creek work was really mitigation, monitoring of sediments in the project area and downstrealD, best management practices, buffer ·width, how wet the left bank is in Reach 4, the need for future dredging. Ecology followed up bye-mail documenting questions raised at the 4/26/11 site visit. Gerald Wasser From: Sent: To: Cc: Subject: Julie P. Bonwell Obonwell@lesourd.com] Friday, September 09, 2011 3:37 PM Gerald Wasser Hebe Bernardo LUA 11-065 May Creek Project Gerald C. Wasser, Associate Planner City of Renton Dear Mr. Wasser: EXHIBIT 16 PLEASE DO NOT ISSUE A PERMIT TO THE COUNTY ON THEIR PROPOSED PROJECT ON MAY CREEK. Our family home is immediately downstream of the proposed project. Access to our home is across a privately-owned bridge built many years ago. We have witnessed firsthand the damaging effects of runoff and erosion on our creek banks and bridge abutments and believe the project as currently proposed to be meritless. We feel vulnerable, even threatened, by the County's proposal to dredge and relocate a stream bed in an effort to "enhance" drainage of a wet land (horse pasture). We experience seasonal flooding on our property. We believe the project without consideration for the homeowners most impacted, from beginning right down to the type of trees it intends to replant. The County should be measuring bank stability and bank erosion of the specific areas at risk. Permits to the County at this juncture are premature at best. Julie & Jim Bonwell Katie Bonwell 2914 Lyons Avenue NE Renton, WA 98059 1 Gerald Wasser From: Sent: To: Jennifer T. Henning Thursday, September 15, 20112:19 PM Gerald Wasser EXHIBIT 17 - , .. Subject: FW: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 401c and CZM Attachments: May Creek Dredging 401c and CZM Public Notice comments. pdf From: Karen Walter [KWalter@muckleshoot.nsn.usJ Sent: Thursday, September 15, 2a11 2:a6 PM To: ECY RE FED PERMITS Cc: Lull, Lori C NWS; Randy McIntosh; 'Fisher, Larry D (DFW)'; Padgett, Rebekah (ECY); McGraner, Patrick (ECY); Dave Garland; Jennifer T. Henning; Chin, Doug; Hartley, James Subject: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 4a1c and CZM To Whom It May Concern, Attached you will find comments from the Muckleshoot Indian Tribe Fisheries Division in response to the Public Notice of Application for the above referenced project. A signed hard copy has also been sent to the Olympia office of Ecology. Please let me know if you have any questions. Thank you, Karen Walter Watersheds and Land Use Team Leader Muckleshoot Indian Tribe Fisheries Division 39a15 172nd Ave SE Auburn, WA 98092 253-876-3116 1 · MUCKLESHOOT INDIAN TRIBE Fisheries Division 39015 -172'd Avenue SE • Auburn, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 May 11,2011 Washington Department of Ecology-SEA Program Federal Project Coordinator P.O. Box 47600 Olympia, W A 98504 RE: May Creek Drainage Improvement Project 401c and CZM Consistency Public Notice of Application. Dear Sir or Madame: The Muckleshoot Indian Tribe Fisheries Division (MlTFD) has reviewed the Public Notice of Application for a State of Washington 401 Water Quality Certification and Coastal Zone Management Act Consistency for the May Creek Drainage Improvement Project. This project is the first of potentially four phases to dredge May Creek. In this first phase, the project proposes to dredge May Creek from Rivermile 4.3 to Rivermile 4.9, removing sediments, reed canarygrass and some of the existing willows that are within the flooded area of concern. As noted in previous comments, the M1TFD has expressed concerns about proposals to dredge May Creek because of potential adverse impacts to salmon and their habitats. This project proposes to dredge 2,000 linear feet of May Creek and its associated wetland in areas identified as salmon spawning and rearing habitat (May Creek Baseline Stream Conditions Report). As noted in various May Creek documents reviewed, this is the first dredging proposal of potentially four projects that would result in the dredging of 2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. The combined impact of all of these dredging projects would likely result in a significant loss of existing salmon habitat, and potentially future adverse impacts upstream and downstream from the dredged reaches as other landowners seek to protect their properties from bank erosion.· We recommend that King County implement and exhaust all less impacting alternatives prior to dredging May Creek. We remain concerned that this proj ect will adversely affect salmon and aquatic habitats without sufficient mitigation for these impacts. The project proposes to directly impact the natural process of sedimentation and floodwater storage along May Creek without adequately assessing the potential impacts to salmon and their habitat in the project area and in upstream and downstream areas. In particular, the potential pre-and post-project rearing habitat available for juvenile salmon in May Creek has not been quantified .. Furthermore, for those impacts which have been quantified, the project impacts exceed the proposed mitigation in length and area. While the proposal to fence and plant native wetland! riparian vegetation I Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401c and CZM Public Notice May 11, 2011 Page 2 . and create alcoves with wood and sediment is an improvement over the existing conditions for most of the project area, the extent of these mitigation measures is insufficient to mitigate for the potential loss of 48,000 square feet ofinstream habitat as aresult of this dredging project. The planting buffer is significantly less than the regulated buffer and would provide inadequate riparian functions as a result. Additional mitigation for this project will Iikelybe required to fully mitigate for the unavoidable environmental impacts from the project. Mitigation should include maximizing the natural processes that create and sustain salmon habitat including: I) improving pasture conditions and controlling other existing sediment sources through agricultural best management practices, farm conservation plans, and other measures as appropriate; 2) greatly minimizing the dredge area; 3) adding additional habitat mitigation to the dredged portion; 4) increasing the streamlwetland buffer width to the regulated 25 foot buffer width and increase riparian plantings; 5) avoid impacting downstream portions of May Creek; and 6) mitigating any unavoidable inlpacts to downstream areas. We are concerned that this project is a "short term fix" and that there is a high likelihood that additional dredging will be proposed elsewhere and/or in the future that may again adversely affect May Creek, its associated wetlands, and potentially the mitigation implemented for this project. Instead we recommend focusing more effort on the obvious land use and pasture~ related sediment sources and allow the May Creek more room to store and. transport its sediment load, consistent with natural stream processes. Additional specific comments and questions about this project are attached for your review and consideration. Please let me know if you have anY'questions at 253-876-3116. Sincerely, KMw\V~ Karen Walter Watersheds and Land Use Team Leader Cc: Lori Lull, USACOE Randy McIntosh, NMFS Larry Fisher, WDFW Region 4 Rebekah Padgett, WDOE, NW Region Patrick McGranger, WDOE, NW Region Dave Garland, WDOE, NW Region Jennifer Henning, City of Renton Planning Doug Chin, King County DNRP Jamie Hartley, King County DDES Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice Other Potential Alternatives . May 11, 2011 Page 3 We are concerned that King County has not fully pursued all available alternatives that could reduce the need to dredge the entire area proposed under Phase I (and future phases) and reduce the amount of native vegetation removals to better protect existing instream and riparian functions. For example, most of the properties that would benefit from Phase I dredging are used for livestock pasture. King County Code (Title 21.AJO) regulates these areas to "support the raising and keeping of livestock in the county in a manner that minimizes the adverse impacts of livestock on the environment particularly with regard to their impacts on water quality and salmonidfisheries habitat in King County watersheds". It is not clear how the adjacent properties are in compliance with this code which limits the maximum number of livestock on a per acre basis. As part of the Code compliance, property owners are required to have a farm plan with maximum densities of livestock. These farm plans require: "Site-specific management measures for minimizing nonpoint pollution from agricultural activities and for managing wetland and aquatic areas including, but not limited to: a. livestock watering; b. grazing and pasture management; c. confinement area management; d manure management; and e. exclusion of animals from aquatic areas and their buffers and wetlands and their buffers with the exception of grazed wet meadows." (KCC 21A.30.045.2). It should be noted that KCC 21.AJO.04S.B requires that farm management plans seek to achieve a "minimum 25 foot buffer of diverse, mature vegetation between grazing areas,and the ordinary high water mark of all type S and F aquatic areas and the wetland edge of any category I, II or III wetland with the exception of grazed wet meadows, using buffer averaging where necessary to accommodate existing structures." The proposed mitigation buffer for dredging is a maximum of IS feet that is substantially less that the County Code. Another problem is that the mitigation buffer area is not proposed to be permanently protected in a conservation easement. From our field visit on April 26, 2011, it appears that the properties in question are not complying with King County Code Title 21.A.30. Prior to the approval of any dredging proposal that will adversely impact salmon habitat in May Creek, we recommend that the properties demonstrate compliance with Title 21.AJO in that the property owners have minimized their contributions to the sedimentation and flooding problem, including providing a vegetated buffer to control sediment loading and shading out the existing reed canary grass in and along May Creek and its tributaries. The project should also evaluate the potential for the existing SE 148 th Street Bridge to create an obstruction and create backwater conditions that cause sediment to deposit upstream. Per the Hydraulic and Hydrologic Analyses for the project (December 2010), this bridge cannot pass a I ~O-year flood without overtopping the roadway. I' , I I I Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice Project benefits May 11, 2011 Page 4 The purpose of the project is to reduce the duration of flooding on local property owners by removing in- stream channel obstructions. There should be further analysis that discusses how much used pasture area will have reduced flooding and for what duration for each of the affected properties to determine project impacts versus potential benefits. The Hydraulic and Hydrologic Analysis report suggests that the decrease in flood durations at 100 cfs is 7 hours which suggests little benefit for substantial environmental . impacts to May Creek. Project Impacts We are concerned that the existing rearing habitat in May Creek will be lost through the combination of channel dredging, reed canarygrass removal, and removal of in-water and adjacent willows. There is no estimate given for the potential loss of rearing habitat. However, the impact analysis indicates that the total impact area is 43,995 square feet (1.01 acres), whereas, the proposed mitigation area at the two off- channel alcoves is 10,238 square feet (0.24 acres). This is less than a 1:1 ratio of impact to mitigation area and will likely result in unmitigated impacts to existing rearing habitat for juvenile salmon. In addition, details are lacking regarding the flood event needed to connect the alcoves to May Creek, the corresponding water depth in the alcoves, how long they will be inundated, and how much rearing habitat would be created. If the alcoves are not fully connected to May Creek or the entire area is not inundated, then the mitigation area alcoves may actual provide less habitat than the proposed 10,238 square feet and also may potentially result in stranding mortality. The project has not adequately described or analyzed the sediment sources coming into May Creek from Long Marsh Creek. For example, it is not clear if undersized culverts on Long Marsh Creek are contributing to bank erosion and contributing to the sediment load. Alternatively, upstream stormwater contribution may be causing sediment transport in Long Marsh Creek too. Additional information is needed to assess the contribution from Long Marsh Creek and if needed, measures taken since Long Marsh Creek was identified a major contribution in the County's sediment assessment report. Finally, we . do not view the proposed Long Marsh Creek work as mitigation for reasons noted below. It is also unknown what benefit, if any, would occur from creating a side channel at the Long Marsh/May Creek confluence to trap sediment. It seems likely that this constructed feature would fill in from upstream sediment, since the mitigation design is not providing sufficient width in the upstream portions of Long Marsh Creek to slow down the rate of sediment transport and retain sediment in the channel upstream. In addition, the proposal to remove existing red alders that are 10-15 years old with smaller trees in the same 15 foot wide buffer on Long Marsh Creek is an impact, not mitigation, The project may not have fully considered potential impacts to Chinook, coho, and sockeye salmon, According to the Stream and Wetland Impact Analysis and Mitigation Plan, King County indicates that chinook and sockeye salmon do not travel upstream as far as May Valley. However, King County has data from the Salmon Watcher's program that indicates that adult Chinook, sockeye, and coho were reported as far upstream as Greene's Creek in 2001, which is just downstream of the SE 148 th bridge. (see http://your.kingcountv.gov/dnm/library/archive- " . ------------------------- Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401c and CZM Public Notice documents/wlr/waterres/salmon/Maps/200 1I0205distroEASTlake W Apdf). May 11, 2011 Page 5 The project also needs to mitigate for the loss of the full channel spanning pool at the Long Marsh Creek confluence. This pool will be eliminated by the stream dredging and not replaced based on the proposed mitigation plans. Since pools are limited in this portion of May Creek per the baseline stream conditions report, the pool should be replaced, potentially downstream of SE l48'h adjacent to the NGPE tract for Stonegate where there are fewer constraints. Alluvial fans are natural features at Long Marsh Creek and farther upstream at Indian Meadow Creek. According to the sediment assessment report, these features have been documented in the May Creek Valley since 1872. As a result, they will likely be continued sources of sediment to May Creek. Phase I and the future phases need to develop strategies that accommodate these natural features instead of proposing dredging now and into the future. The project may also aggravate existing conditions for water temperature and dissolved oxygen in May Creek. Currently May Creek through the May Valley is shown as a "Category 2" water for temperature and dissolved oxygen on Ecology's 2008 303(d) list. The removal of vegetation along 0.6 miles of May Creek that currently provides shade may worsen this condition. Once a redesigned project has been developed that addresses the concerns above, then a water quality protection plan and a monitoring plan that assesses the project's effects on sediment transport/filling, flooding, habitat creation and riparian planting success can be developed. Any approved project should be monitored for 10 years to determine project success ( or failure) prior to allow any new dredging. I I CITY OF NEWCASTLE TOWNSHIP PROJECT LOCATION (/) z o ~ -_1-:: EXHIBIT 18 S£ MAY VALU" "T RD CITY OF RENTON ,,'rON EGATE 803S40 UNDIVIDED INTEREST TRACT "A" CITY OF RENTON w (/) w ~ THE EXISTING PHYSICAL FEATURES SHOWN ON THIS PLAN ARE FROM G.I.S. PROJECT TITLE: I ':-20::-::0----'~ I MAY CREEK DRAINAGE IMPROVEMENT SCALE I N FEET I TO SInE: SHEET TITLE: til' FROM COAL CREEK PARKWAY (EAST OF VICINITY MAP 1-405) TURN EAST ON S.E. MAY VALLEY SCALE: H: 1" = 200' GO TO 148TH AVE S.E .. TURN SOUTH ASSISTANCE BY: LINDSEY MILLER MAY CREEK. DRAWN BY: MEREDITH RADELLA King County / "- • ~ • i • / / • I I / / / / / / / / / / / / I / I / -----L..t- I :1} / EXHIBIT 19 1/ r ~I ' "~ ~~i ~III I ~I '/ I ~f / I / / / ---z -- RECEIVED MAR 1 5 2011 K.C. Roads Engineering &rvires NMFS Tracking Number. 2011100601 Erick Thompson Road Services Division Department of Transportation KSC-TR-023I 201 S. Jackson Street Seattle, Washington 98104-3856 EXHIBIT 20 UNITED STATES DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration NATIONAL MARINE FlSHERIES SERVICE Northwest Reg ion 7600 Sand Point Way N.E., Bldg. 1 Seattle, Washington 98115 March 10, 2011 Re: Endangered Species Act Section 7 Informal Consultation and Magnuson-Stevens Fishery Conservation and Management Act Essential Fish Habitat Consultation for King County for the May Creek Drainage Improvement Project (Sixth-field Hydrologic Unit Code 171100120400, Lake Washington-Sammamish River). Dear Mr. Thompson: This correspondence is in response to your request for informal consultation under the Endangered Species Act (ESA) of 1973, as amended, 16 U.S.C. 1531. The National Marine Fisheries Service (NMFS) has reviewed the Biological Assessment (BA) for the above referenced proposal, received on February 25, 2011. King County (County) requested concurrence with its determination that the proposed action "may affect, but is not likely to adversely affect" the threatened Puget Sound (PS) Chinook salmon (Oncorhynchus tshawytscha) (70 FR 37160), and the threatened PS Steelbead (0. myldss) (72 FR 26722). This consultation with the County is conducted under section 7(a)(2) of the ESA, and its implementing regulations, 50 CFR Part 402. There is no critical habitat in the action area The County is proposing to improve in-stream flow conditions between approximately river mile (RM) 4.3 and 4.9 of May Creek. Sediment accumulation and in-stream vegetation have been gradually decreasing channel flow capacity, causing a backwater effect and increasing flood duration on pastures. The project includes vegetation and sediment removal, along with stream and wetland mitigation. Invasive reed canary grass and sediment will be removed from the channel with machinery, most likely a trackboe operated from the bank. The stream will be diverted around the work site, and erosion and sediment control best management practices will be implemented. In addition, willows that are obstructing flow , would be removed by hand or with hand-held machinery. Approximately 4,050 cubic yards of material will be removed from the stream channel. 2 As mitigation for these. actions, the County will enhance about two acres of wetland and riparian habitat by suppressing invasive vegetation and replanting with native vegetation. Fencing will be installed around the planting areas to minimize livestock access to the stream. In-stream mitigation activities will also occur at two locations. At the first site on May Creek, the County will excavate off-channel alcoves, and enhance them with large woody debris and native vegetation. At the second site, the County will create meanders and plant native vegetation along 300 feet of Long Marsh Creek at the confluence with May Creek. A 100-foot long side channel will also be created at this site. These mitigation activities will increase habitat complexity and overwintering habitat, and increase sediment retention capabilities, reducing sediment transport to downstream reaches. The in-water work window will be August 1 through 31. In-water work will be limited to activities required to bypass the creek, including fish exclusion and installation of cofferdams. The action area will extend for 300 feet downstream of the downstream-most in-water work (i.e. to RM 4.2) to account for increased suspended sediment concentrations. In general, this type of project could affect ESA listed salmonids by increasing the amount of suspended sediments in the stream, by injuring fish with equipment, or by displacing fish from the project site. In addition, removal of vegetation from the riparian zone and stream channel could potentially affect shade, cover, and allochthonous input. . Species Determination Neither PS Chinook salmon or PS steelhead have been documented within about 0.75 miles of the project action area. Thus, potential direct effects, including injury and displacement from equipment and in-stream work, will be discountable. The County will divert flows around the work site, helping to decrease the amount of suspended sediments drifting downstream. Also, suspended sediment concentrations will dissipate before reaching PS Chinook salmon or steelhead habitat, so potential effects will be insignificant. Potential reductions in shade, cover, and allochthonous input will have insignificant effects due to distance of the action area from PS Chinook salmon and steelhead habitat. The NMFS concurs with the County's determination that ilie project "may affect, but is not likely to adversely affect" PS Chinook salmon and PS steelhead; This concludes informal consultation on these actions in accordance with 50 CFR 402.14(b )(J). The County must reinitiate the ESA consultation if: (1) new information reveals effects of the actions that may affect listed species in a way not previously considered; (2) the actions are modified in a manner that causes an effect On the listed species that was not previously considered; or (3) a new species is listed, or critical habitat is designated, that may be affected by the proposed actions. • 3 Magnuson-Stevens Fisbery Conservation and Management Act Federal agencies are required, under section 305(b)(2) of the MSA and its implementing regulations (50 CPR 600 Subpart K), to consult with NOAA Fisheries regarcling actions that are authorize,d, funded, or undertaken by that agency that may adversely affect Essential Fish Habitat (EFH). The MSA section 3 defines EFH as "those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity". If an action'would adversely affect EFH, NMFS is required to provide the Federal action agency with EFH conservation recommendations (MSA section 305(b)(4)(A». This consultation is based, in part, on information provided by the Federal action agency and descriptions ofEFH for Pacific salmon contained in Appendix A to Amendment 14 to the Pacific Coast Salmon Plan (August 1999) developed by the Pacific Fishery Management Council and approved by the Secretary of Comnierce (September 27, 2000). The proposed action and action area are described in this letter and in the BA. The action area includes habitat that has been designated as EFH for various life stages of Chinook and coho (0. kisutch) salmon. . EFH Conservation Recommendations: Because the conservation measures that the Comity included as part of the proposed action to address ESA concerns are also adequate to avoid, minimize, or otherwise offset potential adverse impacts to the EFH of the species listed ' above, conservation recommendations pursuant to MSA (section 305(b)(4)(A» are not necessary. SinCe NMFS is not providing conservation recommendations at this time, no 30- day response from the County is required (MSA section 305(b)(4)(B»). This concludes consultation under the MSA. If the proposed action is modified in a manner that may adversely affect EFH, or if new information becomes available that affects the basis for NMFS' EFH conservation recommendations, the County will need to reinitiate EFH consultation with NMFS in accordance with implementing regulations for EFH at 50 CFR 600.920(k). The NMFS appreciates your efforts to comply with requirements under the ESA and MSA. lfyou bave questions, please contact Jody Walters at the Washington State Habitat Office, (360) 534-9307, or email Jody.Walters@noaagov. Sincerely, ce: Lori Lull, COE ,(; William W \J Regional A=="r;ator STATE OF WASHINGTON DEPARTMENT OF ECOLOGY EXHIBIT 21 Northwest Regional O/flee 3190 160th SE Bellel'lle, Washingtoll 98008-5452 (425) 649-7000 September 22, 2011 Doug Chin, Project Manager King County Water and.Land Resources Division 20 I South Jackson Street, Suite 600 Seattle, WA 98104-3855 RE: Ecology Denial fOI" Section 401 Water Quality Certification for the May Creek Drainage Improvement Project, Renton, King County, Washington Deal' Mr. Chin: The U.S. Army Corps of Engineers (Corps) issued ajoint public notice with the Washington State Department of Ecology (Ecology) for the above project on September 24,2010. Ecology has one year to issue an individual Section 401 Water Quality Certification (401 Certification). On August 31,2010, Ecology notified you by celtified letter that this project would requirc a 40 I Celtification. On April 21, 2011 and Scptembcr 1,2011, Ecology issued additional public notices regarding King County's two revised applications for 40 I Certification. We determined that your application for an individual 401 Celtification was incomplete and sent you a certificd letter on September 1,2.011 detailing the specific information that was necded to complete your application and stating that if Ecology did not receive all of the required documentation by September 16,2011, Ecology would deny the 401 Celtification for this project. In our September 1, 20 II letter we identified the following infOlmation needed in order to complete our review: • A description of how sediment disposal areas will be stabilized. • A Construction Water Quality Protection and Monitoring Plan. o Measures to be taken regarding stream water temperature changcs between removal of mature vegetation and when replanted vegetation reaches the size to shade the creek. o Revisions to the Mitigation Plan. o Revisions to the sediment monitoring plan. o Site plan revisions. . o Details on the Long Marsh Creek riparian planting buffer. o A copy ofthe Final Long Marsh Crcek Sediment Control and Habitat Restoration Project Basis of Design Report. o Expanded riparian vegetation buffers. o Study of the resizing or removal of the 148'h Avenue SE Bridge. King County Water and Land Resources Division' September 22, 20 II Page 2 • Reassessment and redesign of the project to address its effectiveness, including further evaluation and study of sediment transport and downstream erosion, as well as independent review of sediment transport modeling. On September 16, 20 II, Ecology received a response addressing some of the infOlmation requested. Unfortunately we have not received all of the documentation nccded in ordcr to demonstrate that we have reasonable assw-ancc that state water quality standards will be met. We have attached a project chronology that details that we have been trying to work with you to get the needed infOlmation in order to process your request for a 40 I Certification. Pursuant to Section 401 ofthe Clean Water Act. ch. 90.48 RCW and ch. 173-20 IA WAC, the May Creek Drainage Improvement Project water quality certification is denied without prejudice. Receipt of a denial without prejudice does not preclude King County Water and Land Resources Division from resubmitting a request for 401 Certification at a later date. You have a right to appeal this Order to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this Order. The appeal process is governed by Chapter 43.21B RCW and Chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.00I(2). To appeal you must do the following within 30 days of the date of receipt ofthis Order: • File your appeal and a copy of this Order with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. • Serve a copy of your appeal and this Order on Ecology in paper form -by mail or in person. (See addresses below.) E-mail is not accepted. You must also comply with other applicable requirements in Chapter 43.21B RCW and Chapter 371-08 WAC. ~DQRESS\fI:~Plt:O:G~'fl(i[N.rINE,0Bi~1~m.I~~l!:ii~~.~.i&"i'f~~i~~~ ~'$t~~t\;;,'dii~~~~~~c,f2ij:}",'j:,~i;:;::;:::':;,;~,;";;;';~;;:Malllh~,'AdiJ;f~t~~S":g':':'I':i:~I~L,;:";:::;~;::S\':i;2~i=I1i Department of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, W A 98503 Pollution C.ontrol Hearings Board III I Israel Rd SW STE 301 Tumwaler, WA 98501 Department of Ecology Attn: Appeals Processing Desk PO Box 47608 Olympia, W A 98504-7608 Pollution Control Hearings Board , PO Box 40903 Olympia, W A 98504-0903 r---------------------------------------- King County Water and Land Resources Division September 22, 20 II Page 3 . Please direct all questions about this Order to: Rebekah Padgett Department of Ecology Northwest Regional Office 3190 160th Avenue SE Bellevue, W A 98008 (425) 649-7129 Rebekah.Padgett@ecy.wa.gov Pollution Control Hearings Board Website www.eho.wa.gov/Boards PCHB.aspx Chapter 43.21B RCW -Environmental Hearings Office -Pollution Control Hearings Board http://apps.leg.wa.govIRCW/default.aspx?cite=43.21B Chapter 371-08 WAC -Practice and Procedure http://apps.leg.wa.govIWAC/default.aspx?cite=371-08 Chapter 90.48 RCW -Water PolIution Control http://apps.leg.wa.govIRCW/default.aspx?cite=90.48 Chapter 173-201A WAC -Water Quality Standards for Surface Waters of the State of Washington www.ecy.wa.govlbiblio/waeI7320IA.html Erik Stockdale, Unit Supervisor Wetlands/401 Unit Shorelands and Environmental Assistance Program Northwest Regional Office ES:ITp:eja Enclosure By certified mail 7011 04700003 3720 9107 September 22, 2011 ----------------------------------------- King County Water and Land Resources Division September 22, 2011 Pagc4 cc: Lori Lull, U.S. Army Corps of Engineers TJ Stetz, U.S. Army Corps of Engineers Larry Fisher, Washington Deprutment of Fish and Wildlife Karen Walter, Muckleshoot Indian Tribe Katie Bonwell e-cc: Patrick McGraner -NWRO Patricia Olson -HQ Loree' Randall -HQ Raman Iyer -NWRO ecyrefedpelmits@ecy.wa.gov Jennifer Henning, City of Renton Jhenning@Rentonwa.gov Jean Rollins urbanseparator@hotmail.com Debra Rogers herogers@comcast.net Susan Malin susiemalin@msn.com Gru'Y Amundson gary.a@comcast.net Andrew Duffils klassicars@hotmail.com Carol Tabacek caroltabacek@aol.com Mary Weirich mruyvweirich@comcast.net A. Duffus blueheron6987@hotmail.com Julie & Jim Bonwell ibonwell@lesourd.com 1126/10 2/22110 3/24/10 515110 5/13/10 6/24/10 Attachment 1: May Creek WQC Permitting Chronology Ecology attended an interagency meeting organized by King County with discussion about the 'potential to create a multi-agency permitting team. A brief introduction and overview ofthe project concept at this early stage was presented. The U.S. Almy Corps of Engineers (Corps), Ecology, Washington Deprutment of Fish and Wildlife (WDFW), Muckleshoot Indian Tribe, Governor's Office of Regulatory Assistance, and King County representatives were present. Ecology attended a field meeting with King County, WDFW, and the Muckleshoot Indian Tribe. Ecology staff raised concerns about the effectiveness, purpose and need of the proposed project. Specific comments included: the effectiveness of the 15-foot-wide buffers, concerns about direct animal access to stream, severely degraded pastures and the need for farm plans, extent of the wetland and primary sources of hydrology, and concerns about establishing woody vegetation in very wet soils. Ecology observed that livestock have direct access on one of the project properties upstream of the project area. Ecology provided written comments via e-mail that followed up on the 2/2211 0 site visit. Ecology participated in an interagency pre-application meeting and provided substantive comments regarding the effectiveness, pW'Pose, and need of the project, as well as the need to redelineate the wetland, buffer width, and limit livestock access to the creek. Ecology raised concerns about 303( d) listing for, fecal coliform and the preference for 35-foot buffers and wider planting on the south side buffer to reduce summer temperatures through shading. Ecology questioned the 2002 pilot described by King County where two sediment plugs were removed from side channels on the McFarland property, specifically whether it would be comparable to the current proposal and what post- construction monitoring was completed. Ecology raised the question of whether the proposed one-time dredging would accomplish the goals of the proposal; the County indicated that it was planning a series of projects, working from this site upstream. Ecology also pointed out that the baseline stream report included language that contradicted and would not support this proposal. Downstream erosion concerns were discussed, and King County staff noted that they had conducted modeling and did not believe that the sediment removal would increase erosion downsb·eam. King County submitted the Joint Aquatic Resources Permit Application (JARP A) package to Ecology. The Corps can,celed the application. Ecology canceled the 401 application based on the Corps' 5/13/10 action. King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment 1 September 22, 2011 Page 2 8/16/10 9/8/10 9/16/10 9/20110 9/22110 9/24/10 10110 10/23110 12/16110 3/3/11 3/18/11 King County submitted a revised JARPA to Ecology. King County submitted a Certification of Consistency with the Washington State Coastal Zone Management (CZM) Program to Ecology. Ecology submitted comments on the State Environmental Policy Act mitigated determination of non-significance (MONS) regarding effectiveness, purpose, and need of the proposal, buffer width, how wet the left bank is in Reach 4 for establishing canopy cover, the degradation of the pastures and need for farm plans to protect riparian habitat and creeks, and livestock access to the creek. Ecology received substantive public comments from downstream residents. Issues raised iocluded concerns about iocreased erosion, sediment transport thresholds, cumulative impacts, and the need for additional detailed study of the potential downstream impacts. Ecology received substantive public comments from the Muckleshoot Indian Tribe raising concerns about net loss of habitat, downstream erosion, insufficient buffers and the probability that the proposed dredging will be a short-term fix. Corps issued a joint public notice with Ecology. Ecology received substantive public comments from downstream residents. Issues raised included concerns about the purpose and need of the project, draining of wetlands, water quality, salmon habitat, increased flow, and bank erosion, as well as questions about the 2002 pilot. Ecology received substantive public comments from the City of Renton that iocluded concern about effects of increased velocity, flow, or erosion on downstream properties. Ecology received King County's responses to Ecology MONS comments. In the response letter, the County defends the proposed 15-foot buffer not as best available science (BAS) but as an improvement over existing conditions citing property owners' reluctance to expand planting areas, states that it cannot require frum plans from private property ow.Jler~. or require owners with farm plans to implement them properly, and notes that the planting areas will be fenced and will therefore effectively eliminate livestock access to the creek. Ecology and King County jointly extended the CZM review period until 9/8/11. King County submitted another revised J ARP A to Ecology. This revision included new impacts to Long Mru'sh Creek that the County refened to as miti~ation, therefore reducing proposed mitigation downstream of 148' Avenue SE. King County Water and Land Resources Division May Creek Drainage Improvement Project Attaclunent 1 September 22, 2011 Page 3 4/5111 4/2111 I 4/26111 4/28/11 5/1\ 5/11111 Ecology received substantive public comments from the Neighbors for lylay Valley, who raised concerns about stream flow velocity, volume and timing of storm events, flooding and erosion. Downstream property owners requested that King County allow the project to be delayed at least one water year to establish a pre-project erosion baseline. The downstream citizens requested additional assurances that the proposed dredging will not have unintended negative consequences to downstream properties. Ecology issued a public notice on the revised application. Ecology participated in an interagency site visit where staff raised questions about the effectiveness, purpose, and need ofthe project, permanent protection of the mitigation area, the buffers on Long Marsh Creek, whether the Long Marsh Creek work was really mitigation, project-specific monitoring of sediments in the project area and downstream, best management practices, proposed buffer widths, how wet the left bank is in Reach 4, and the need for future dredging. Ecology followed up bye-mail documenting questions raised at the 4/26/11 site visit. Ecology received substantive public comments from downstream property owners questioning assumptions being made by King County based on modeling within the Hydraulics and Hydrologic Analyses using limited data, expressing concerns about downstrcam erosion, increased turbidity, and the proposed IS-foot planting buffer as not meeting BAS or County code. Specific questions also were raised with regards to the adequacy of the information provided by King County that claimed that the 2002 pilot project along a 300-foot section of the creek upstream of the proposed project was successful, erosion thresholds, potential for shallow welJ contamination, flow velocity, volume and peak flow during storm events potentially Iisking sole-access blidges to properties, and the adequacy of the 15- foot planting buffer. Ecology received additional substantive comments from the Muckleshoot Indian Tlibe emphasizing the need to improve pastw'e conditions and control other existing sediment sources through agricultural best management practices and/or . farm plans, minimize the dredging area with increased mitigation for impacts, increase the proposed planted buffer width, provide additional riparian plantings, measures to avoid impacts to downstream reaches, mitigation for any unavoidable impact to downstream reaches, future dredging projects, and potential impacts to . salmonids. King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment I September 22,2011 Page 4 6/10111 711111 7/8/11 7/19/11 7122111 Ecology received King County's responses to Ecology's 4/26/11 and 4/28/11 comments. In its letter, King County stated that downstream impacts have been sufficiently analyzed and that a fonnal monitoring plan is not wananted; based on previous analysis and cunent design features, re-sedimentation monitoring is not wan·anted at this time; and there are no future plans to implement additional upstream sediment removal projects. King County continued to defend the proposed IS-foot buffer as being adequate even within the very wet portion of the left bank in Reach 4. In response to ongoing concerns from Ecology regarding the effectiveness of the proposed project, King County again stated that the project is only designed to reduce overbank pasture flooding for a short period of time on each end of the rainy season and that monitoring wells have been installed to assess groundwater pre-and post-project. Ecology received King County's responses to a public comment in which the County restated that the 15-foot proposed planting buffer, while not based on BAS, is an improvement over existing conditions as demonstrated by the results of the 2002 pilot project upstream of the cUlTent proposal and that the continuous hydrologic watershed mode used accounted for all peaks, all durations and all . flow rates at all locations. King County reversed its position from 6/10111 and . agreed to conduct downstream monitoring for a period of 5 years post-project. Ecology responded to King County by requesting a copy of the downstream monitoring plan with note that the plan should be comprehensive and not simply address the issues raised by one property owner. Ecology received King County's responses to a public comment in which the County stated that downstream monitoring will be conducted for a period of 5 years and that if monitoring data collected clearly shows that erosion problems result from the project, that it will offer technical assistance and perfol1"O remediation. The County indicated that it has no future plans to implement additional sediment removal projects upstream of this project site. Ecology received King County's responses to a public comment stating that the project will not increase existing erosion problems downstream, proposing 5 years of downstream monitoring and working with the propeliy owner on a solution if the monitoring shows downstream erosion resulting from this project. Ecology received King County's responses to the Muckleshoot Indian Tribe 5111111 comments. The e-mail states that the COlmty does not have plans to implement the other three upstream dredging projects. In response to the tribe's comment that King County Code requires existing livestock operations to implement a farm management plan or meet management standards outlined in the Code, the County indicates that two of the four livestock operations have developed plans and that the buffers specified in these plans are 25 feet (l0 feet more than the County is proposing through this project). The County also acknowledges that the 148th Avenue SE Bridge causes a backwater effect. --------------------------- King County Water and Land Resources Division May Creek Drainage Improvement Project Attachment I September 22, 20 II Page 5' 7/26/11 8/2111 911/11 9/7/11 9/14/11 9/15111 9/16/11 Ecology again visited the project site, including downstream properties. King County submitted another revised JARP A. The revision addresses Long Marsh Creek impacts and includes additional mitigation. Ecology sent a letter by Certified Mail to Doug Chin requesting additional infOlmation and stating that project 401 Celiification would be denied if the requested documentation was not received at Ecology by September 16, 2011. Ecology issued a public notice on the revised application . . Ecology and King County jointly extended the CZM review period until 11/8/11. Ecology received a public comment from a property owner reiterating questions about the need for the project and concems about downstream erosion and flooding impacts Ecology received public comments from a propeJ.ty owner reiterating coneems about downstream erosion and flooding impacts, raising the need for additional erosion monitoring and stream flow devices, and questioning the need for the project. The property owner raises questions about the stream and wetland buffer width, storm surge flows, hydraulic and hydrologic analysis, cumulative impacts, compensatory stormwater storage, and the need for additional data and analysis. Ecology received public comments from the Muckleshoot Indian Tribe reiterating concerns about salmonids and habitat, cumulative impacts, likely future dredging, insufficient buffer widths, and the adequacy of mitigation. The letter also notes the need to consider less-impacting alternatives, have enforceable farm plans in place, for further analysis On backwater effect of the McFarlandlGambini footbridge, to consider impacts of sediment deposition in the mitigation alcoves, for sediment accumulation and erosion monitoring, to collect data rega£ding changes in channel cross-sections and longitudinal profiles and data on flood frequency durations, to monitor for salmonid use, and for a contingency plan. Ecology received additional public comments reiterating concerns about downstream flooding and erosion. Ecology received King County's responses to the 9/1/11 letter requesting additional information. While some questions were addressed, outstanding issues remain including: buffers, baseline data, and sediment transport and data about what will happen downstream. . A. Duffus 143rd Avenue SE Renton, WA 98059-3764 October 3,2011 Phil Olbrecht Renton Hearing Examiner City of Renton 1055 South Grady way Renton, WA 98057 Re: LUAll-065. V-H SP May Creek DredgingProject Dear. Mr. Olbrecht: EXHIBIT 22 This Master Application is part of a larger proposal to dredge May Creek. The project is an ill-conceived attempt to temporally reduce seasonal flooding in a grazed wetland, i.e. horse pastures! To accomplish this over 2000 lineal feet of May Creek will be dredged. Once dredged, the King County Water & Land Resources Division expects that storm-water will flow more freely downstream. Downstream properties already experience flooding and erosion that threatens our homes, rips away our property and imperils our sole-access- private-bridges. Repeat, our only access private bridges. (These bridges are our only way out because of development patterns and lack of easements. Repairing or replacing is prohibitive due to environmental regulations and the financial burden.) Downstre3.m property owners and state, federal, and tribal agencies are strongly opposed to this dredging proposal because of the probable significant adverse impacts. The Preliminary Report to the Hearing Examiner is flawed. The report contains substantial errors in fact. There are gaps in relevant information. For example, no reference is made to scientific information available from the Washington State Department of Ecology. The staff recommendation is misguided and is clearly erroneous in light of the documentation. On September 22nd, 2011, the Washington State Dept. of Ecology formally denied King County the right to dredge May Creek. Ecology requires additional baseline information, design changes, assurances that there will be no downstream impacts and further mitigation. (Copy attached.) On August 15 th, 2011, the Department of Ecology released an internal memo from, Dr. Patricia Olson, Ecology's Senior Hydrogeologist. (See August 15, 2011 memo, attached) Dr. Olson, who reviewed all the documentation from King County and personally visited the site, questioned the lack of detail in the county's studies and design, the very effectiveness of the project, uncertainty as to downstream impacts, cost-benefits, etc. I repeat, this memo is from Dr. Patricia L. Olson, Master of Science, J>hD, and licensed hydro-geologist. She is the Senior Hydrogeologist for the State of Washington Department of Ecology. Dr. Olson publishes scientific documents on rivers, lakes and groundwater issues. Dr Olson lectures. Dr. Olson testifies as an expert witness. Dr. Olson's work is actually referenced in King County's documentation for this dredging proposal. The City received a copy of Dr. Olson's memo on September 14th, 2011. Why was this vital document not referenced in the staff report to the Hearing Examiner? I urge the Hearing Examiner to please read Dr. Olson's profession evaluation and give it the substantive weight it deserves in your deliberation. I have personally worked with City of Renton staff and council for almost thirty years. I know the City has good, well-meaning people. Together, we have made our community a better place to live. However, who on the Renton staff reviewed this Master Application? How much time was spent on review and research? What is the staff reviewers' level of expertise? How could they make a recommendation to proceed given Dr. Olson's thorough design review, recent site visit and subsequent damming oUhe proposal? Did city staff visit the site? Did city personnel physically look at the downstream erosion and flooding conditions and the at-risk sole-access-private-bridges? I am hesitant to say the staff's recommendation is arbitrary and capricious, but I am tempted. On September 1st, 2011, the State Department of Ecology informed Water & Land Resources Division that, "Unless we receive all of the above documentation by September 16th , 2011, Ecology will have to deny the WQC/CZM for this project." (Copy attached) The city also received a copy of this letter on September 14th, yet it is not mentioned in the preliminary report. On September 22nd, 2011, Ecology formally denied the Section 401 Water Quality Certification for the May Creek Drainage Improvement Project. While the denial notification acknowledged Ecology "received some of the information requested ... we (Ecology) have not received all of the documentation needed in order to demonstrate that we have reasonable assurance that the state water quality standards will be met." Why is the state Dept. of Ecology denial not given substantial weight? It is a pretty big deal that the state refused to certify the county's proposal! Yet, there is no reference to the state decision to deny certification except in one sentence in the preliminary report. Almost a fOotnote! . MAJOR POINT ! A COPY OF ECOLOGY'S DENIAL WAS NOT EVEN INCLUDED AS ANEXHIBIT in the preliminary report. How can an omission like this occur??? City staffhas not only over looked the facts; there is a gap in relevant information. If the state Department of Ecology in its wisdom, expertise, and experience denies King County the right to dredge, how can the City of Renton even consider approving the Critical Areas Variance and issuing the Special Grade & Fill Permit? Especially; given that the denial is determined, in part, on the probable significant adverse impacts to the critical areas. The Department of Ecology has repeatedly "provided substantive comments (questioning) the effectiveness, purpose, and need of the project." Dr. Olson in her words asks why King County did not consult with the county's very own qualified fluvial geomorphologists and geologists on staff. (See her actual quote in footnote 1. below.) Just two weeks ago, the Muckleshoot Indian Tribe repeated their recommendation, " ... that King County implement and exhaust all less impacting alternatives prior to dredging May Creek ... " (Letter to Washington Department of Ecology-SEA Program dated September 15 th , 2011, copy attached) Apparently, this letter is not included in the preliminary report either. These documents must be accorded substantive weight in the City's decision on this Master Application to Fill & Grade and seek a Critical Areas Variance. The Washington State Dept. of Ecology has denied King County the right to dredge May Creek. Ecology is requesting more baseline information, design changes, assurances that there will be no downstream impacts and further mitigation. Obviously, the project will need to be significantly re-engineered to comply with state and federal requirements. Conceivably additional mitigation may be required in the big wetland. Perhaps additional off-channel alcoves or secondary by-pass channels. Possibly additional stormwater storage to compensate for up-stream dredging and reduction of natural storm water retention. To meet permitting agencies' requests the final design in the Tract A wetland will be quite different from the county's current proposal. The City of Renton cannot assess the probable significant impacts with the information currently available. The state and the Muckleshoot Indian Tribe are asking for larger planting buffers and perhaps more or larger off stream alcoves, all which will increase the impact of the clearing and grading. The City needs to appraise the fina1 design changes before approving the Critical Areas Variance and issuing the Special Grade & Fill Permit. Questions: What will be the impacts of the revised design, both to the wetland and downstream? Will these design changes further disturb this natural wetland, if so to what degree? What further mitigation will be required? The proposed project is in a relatively undisturbed wetland on the rural growth line and is an important part of the wildlife corridor from Cougar Mountain to May Creek Canyon. The project will significantly adversely impact the riparian zone, i.e. fish and wildlife habitat. Three acres of this 3.75-acre wetland (80%) will be impacted by this project. If there are not permanent adverse impacts, there will most certainly be temporary impacts as the creek is dredged and wetland altered. The riparian zone will be cordoned off with orange silt fences. The morning air will be filled with a cacophony of growling diesel engines and piercing backup alarms as heavy construction equipment churns through the wetland. Not to mention the diesel fumes. The county is proposing three-strand barbwire fences. Hardly user friendly for wildlife! The city's own regulations call for no fences in opens spaces unless absolutely necessary. In the past, when necessary, the city specified split rail cedar. See LUA-05-083 Preliminary Report to the Hearing Examiner, November 29th , 2005. That plat was within the May Valley Urban Separator contiguous-open-space-corridor of which, Stonegate Tract A wetland is a part. (Reference City of Renton map, December 17th, 2004). I ask the Hearing Examiner to follow the precedence set by your predecessor and require split rail fences around the wetland buffer's perimeter, if this Master Application is ever approved. Frankly, I am surprised that the City is pressing ahead with this application. City staff is a scarce resource in this era of restricted public budgets. Processing this application incurs staff and material costs, yet the project is not design fina1ized, nor sanctioned by all permitting agencies. More Questions: Where is the broad citizen support for this expenditure of public funds to benefit a few private interests? This project is to benefit four horse pastures at the risk of many downstream homeowners. Other than county staff, how many citizen dredging proponents testified at the hearing? (See footnote 2.) Where is the state, federal and tribal support? Ecology has denied water quality certification. The Muckleshoot Tribe's opposition is on record. The United States Army Corps of Engineers has concerns and unanswered questions. The Army Corps has not yet made a determination under the Federal Clean Water Act, Essential Fish Habitat nor the Endangered Species Act. Of note, the Army Corps has been reviewing this proposal since September 2010! (See copy enclosed.) Can this project pass a cost benefit analysis? If so, where is it? This proposal has no economic value to the City of Renton or its citizens. In fact, there is the possibility of downstream liability to the environment, and public and private infrastructure. This could result in far reaching lawsuits. I urge the City wait until this project has been fully justified and designed. The State Dept. of Ecology is not satisfied with the proposal including the mitigation in the wetland within Renton City limits. More mitigation will be required, which could expand the clearing and grading footprint. The project is not yet fully designed. In good faith, the city cannot grant a Critical Areas Variance for a proposal that is incomplete. A proposal that has been denied Section 401 Water Quality Certification by the State. A proposal that has not yet had a decision rendered by the Army Corps of Engineers under Section 404 of the Clean Water Act. I urge the Hearing Examiner to read and give full weight and consideration to Dr. Olson's memo and the Department of Ecology's letters of September 151 and the subsequent denial of September 22nd , 2011. Please wait until the state, the feds and the Muckleshoot are satisfied that there will be no adverse impacts to Renton citizens' property, public infrastructure and the environment. I ask that the City of Renton defer to the wisdom, expertise, and experience of the Washington State Dept. of . Ecology. I ask that the City insist that the project be fully engineered to the satisfaction of all public and private stakeholders. Please deny the Critical Areas Variance. Please deny the Special Grade & Fill Permit. Thank you for your thoughtful deliberations. Andre Attachments: Five FOOTNOTES: 1. Excepted from August 15th, 2011 internal state Department of Ecology memo from Patricia 1. Olson, Senior Hydrogeologist, PhD, LHG. "King County's Department of Natural Resources, Water and Land Resources Division have well qualified fluvial geomorphologists and geologists. The proponents of this project and the geomorphologists and geologists are in the same division. However, these qualified people appear to not have been consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomorphic processes that created the current conditions, and downstream channel response including migration to changes in flow and sediment regimes. The expertise is available within the same King County department and division. These people should be consulted on this project." 2. There are seven properties adjacent to May Creek within River Mile 4.3 an 4.9, the proposed project reach. One of these properties is a dedicated open space wetland; a second is an undeveloped-unused property that is obviously a wetland; and a third is not used for farming activity of any kind. The remaining four properties have horse pastures within the seasonally flooded wetlands. None of the homes on these properties is in danger of flooding. . Converselv. between Nile Avenue NE (a.k.a. 14Sth Avenue SE) and Coal Creek Parkway there are 18 homes along the creek and two at-risk sole-access-private-bridges. At least eight of these homes are within 20 to 50 feet of the unstable creek banks and/or close enough to experience flooding. There are also a half a dozen homes down in the flood prone May Creek canyon and the public and private infrastructure at the mouth of May Creek (Barbee Mills). ;; . Gerald Wasser From: Sent: To: Jennifer T Henning Thursday, September 15, 20112:19 PM Gerald Wasser EXHIBIT 23 Subject: FW: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 401 c and CZM Attachments: May Creek Dredging 401c and CZM Public Notice comments.pdf From: Karen Walter [KWalter@muckleshoot.nsn.us] Sent: Thursday, September 15, 2011 2:06 PM To: ECY RE FED PERMITS Cc: Lull, Lori C NWS; Randy McIntosh; 'Fisher, Larry D (DFW)'; Padgett, Rebekah (ECY); McGraner, Patrick (ECY); Dave Garland; Jennifer T. Henning; Chin, Doug; Hartley, James Subject: Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging Public Notice for 401c and CZM To Whom It May Concern, Attached you will find comments from the Muckleshoot Indian Tribe Fisheries Division in response to the Public Notice of Application for the above referenced project. A signed hard copy has also been sent to the Olympia office of Ecology. Please let me know if you have any questions. Thank you, Karen Walter Watersheds and Land Use Team Leader Muckleshoot Indian Tribe Fisheries Division 39015 172nd Ave SE Auburn, WA 98e92 253-876-3116 1 - · MUCKLESHOOT INDIAN TRIBE Fisheries Division 39015 -172"d Avenue SE • Aubum, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 May 11,2011 Washington Department of Ecology-SEA Program Federal Project Coordinator P.O. Box 47600 Olympia, WA 98504 RE: May Creek Drainage Improvement Project 401c and CZM Consistency Public Notice of Application Dear Sir or Madame: The Muckleshoot Indian Tribe Fisheries Division (MITFD) has reviewed the Public Notice of Application for a State of Washington 401 Water Quality Certification and Coastal Zone Management Act Consistency for the May Creek Drainage Improvement Project. This project is the first of potentially four phases to dredge May Creek. In this first phase, the project proposes to dredge May Creek from Rivermile 4.3 to Rivermile 4.9, removing sediments, reed canarygrass and some of the existing willows that are within the flooded area of concern. As noted in previous comments, the MITFD has expressed concerns about proposals to dredge May Creek because of potential adverse impacts to salmon and their habitats. This project proposes to dredge 2,000 linear feet of May Creek and its associated wetland in areas identified as salmon spawning and rearing habitat (May Creek Baseline Stream Conditions Report). As noted in various May Creek documents reviewed, this is the first dredging proposal of potentially four projects that would result in the dredging of 2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. The combined impact of all of these dredging projects would likely result in a significant loss of existing salmon habitat, and potentially future adverse impacts upstream and downstream from the dredged reaches as other landowners seek to protect their properties from bank erosion. We recommend that King County implement and exhaust all less impacting alternatives prior to dredging May Creek. We remain concerned that this project will adversely affect salmon and aquatic habitats without sufficient mitigation for these impacts. The proj ect proposes to directly impact the natural process of sedimentation and floodwater storage along May Creek without adequately assessing the potential impacts to salmon and their habitat in the project area and in upstream and downstream areas. In particular, the potential pre-and post-project rearing habitat available for juvenile salmon in May Creek has not been quantified .. Furthermore, for those impacts which have been quantified, the project impacts exceed the proposed mitigation in length and area. While the proposal to fence and plant native wetland! riparian vegetation I I Muckle'shoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice May 11, 2011 Page 2 . and create alcoves with wood and sediment is an improvement over the existing conditions for most of the project area, the extent of these mitigation measures is insufficient to mitigate for the potential loss of 48,000 square feet of instream habitat as a result of this dredging project. The planting buffer is significantly less than the regulated buffer and would provide inadequate riparian functions as a result. Additional mitigation for this project will likely be required to fully mitigate for the unavoidable environmental impacts from the project. Mitigation should include rnaximizing the natural processes that create and sustain salmon habitat including: I) improving pasture conditions and controlling other existing sediment sources through agricultural best management practices, farm conservation plans, and other measures as appropriate; 2) greatly minimizing the dredge area; 3) adding additional habitat mitigation to the dredged portion; 4) increasing the streamlwetland buffer width to the regulated 25 foot buffer width and increase riparian plantings; 5) avoid impacting downstream portions of May Creek; and 6) mitigating any unavoidable impacts to downstream areas. We are concerned that this project is a "short term fix" and that there is a high llkelihood that additional dredging will be proposed elsewhere and/or in the future that may again adversely affect May Creek, its associated wetlands, and potentially the mitigation implemented for this project. Instead we recommend focusing more effort on the obvious land use and pasturec related sediment sources and allow the May Creek more room to store and. transport its sediment load, consistent with natural stream processes. Additional specific comments and questions about this project are attached for your review and consideration. Please let me know if you have anY'questions at 253-876-3116. Sincerely, K~\V~ Karen Walter Watersheds and Land Use Team Leader Cc: Lori Lull, USACOE Randy McIntosh, NMFS Larry Fisher, WDFW Region 4 Rebekah Padgett, WDOE, NW Region Patrick McGranger, WDOE, NW Region Dave Garland, WDOE, NW Region Jennifer Henning, City of Renton Planning Doug Chin, King County DNRP Jamie Hartley, King County DDES Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice Other Potential Alternatives . May 11, 2011 Page 3 We are concerned that King County has not fully pursued all available alternatives that could reduce the need to dredge the entire area proposed under Phase I (and future phases) and reduce the amount of native vegetation removals to better protect existing instreatn and riparian functions. For example,most of the properties that would benefit from Phase I dredging are used for livestock pasture. King County Code (Title 21.A.30) regulates these areas to "support the raising and keeping of livestock in the county in a manner that minimizes the adverse impacts of livestock on the environment particularly with regard to their impacts on water quality and salmonid fisheries habitat in King County watersheds ". It is not clear how the adjacent properties are in compliance with this code which limits the maximum number of livestock on a per acre basis. As part of the Code compliance, property owners are required to have a farm plan with maximum densities of livestock. These farm plans require: "Site-specific management measures for minimizing nonpoint pollution from agricultural activities and for managing wetland and aquatic areas including, but not limited to: a. livestock watering; b. grazing and pasture management; C. confinement area management; d manure management; and e. exclusion of animals from aquatic areas and their buffers and wetlands and their buffers with the exception of grazed wet meadows. " (KCC 21A.30.045.2). It should be noted that KCC 21.A.30.045.B requires that farm management plans seek to achieve a "minimum 25 foot buffer of diverse, mature vegetation between grazing areas,and the ordinary high water mark of all type S and F aquatic areas and the wetland edge of any category I, II or III wetland with the exception of grazed wet meadows, using buffer averaging where necessary to accommodate existing structures." The proposed mitigation buffer for dredging is a maximum of 15 feet that is substantially less that the County Code. Another problem is that the mitigation buffer area is not proposed to be permanently protected in a conservation easement. From our field visit on April 26, 2011, it appears that the properties in question are not complying with King County Code Title 21.A.30. Prior to the approval of any dredging proposal that will adversely impact salmon habitat in May Creek, we recommend that the properties demonstrate compliance with Title 21.A.30 in that the property owners have minimized their contributions to the sedimentation and flooding problem, including providing a vegetated buffer to control sediment loading and shading out the existing reed canarygrass in and along May Creek and its tributaries. The project should also evaluate the potential for the existing SE 14Sth Street Bridge to create an obstruction and create backwater conditions that cause sediment to deposit upstream. Per the Hydraulic and Hydrologic Analyses for the project (December 2010), this bridge cannot pass a 100-year flood without overtopping the roadway. I I Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice Project benefits May 11, 2011 Page 4 The purpose of the project is to reduce the duration of flooding on local property owners by removing in- stream channel obstructions. There should be further analysis that discusses how much used pasture area will have reduced flooding and for what duration for each of the affected properties to determine project impacts versus potential benefits. The HydrauJjc and Hydrologic Analysis report suggests that the decrease in flood durations at 100 cfs is 7 hours which suggests little benefit for substantial environmental . impacts to May Creek. Project Impacts We are concerned that the existing rearing habitat in May Creek will be lost through the combination of channel dredging, reed canarygrass removal, and removal of in-water and adjacent willows. There is no estimate given for the potential loss of rearing habitat. However, the impact analysis indicates that the total impact area is 43,995 square feet (\ .01 acres), whereas, the proposed mitigation area at the two off- channel alcoves is 10,238 square feet (0.24 acres). This is less than a 1:1 ratio of impact to mitigation area and will likely result in unmitigated impacts to existing rearing habitat for juvenile salmon. In addition, details are lacking regarding the flood event needed to connect the alcoves to May Creek, the corresponding water depth in the alcoves, how long they will be inundated, and how much rearing habitat would be created. If the alcoves are not fully connected to May Creek or the entire area is not inundated, then the mitigation area alcoves may actual provide less habitat than the proposed 10,238 square feet and also may potentially result in stranding mortality. The project has not adequately described or analyzed the sediment sources coming into May Creek from Long Marsh Creek. For example, it is not clear if undersized culverts on Long Marsh Creek are contributing to bank erosion and contributing to the sediment load. Alternatively, upstream stormwater contribution may be causing sediment transport in Long Marsh Creek too. Additional information is needed to assess the contribution from Long Marsh Creek and if needed, measures taken since Long Marsh Creek was identified a major contribution in the County's sediment assessment report. Finally, we . do not view the proposed Long Marsh Creek work as mitigation for reasons noted below, It is also unknown what benefit, if any, would occur from creating a side channel at the Long MarshlMay Creek confluence to trap sediment. It seems likely that this constructed feature would fill in from upstream sediment, since the mitigation design is not providing sufficient width in the upstream portions of Long Marsh Creek to slow down the rate of sediment transport and retain sediment in the channel upstream. In addition, the proposal to remove existing red alders that are 10-15 years old with smaller trees in the same IS foot wide buffer on Long Marsh Creek is an impact, not mitigation, The project may not have fully considered potential impacts to Chinook, coho, and sockeye salmon. According to the Stream and Wetland Impact Analysis and Mitigation Plan, King County indicates that chinook and sockeye salmon do not travel upstream as far as May Valley. However, King County has data from the Salmon Watcher's program that indicates that adult Chinook, sockeye, and coho were reported as far upstream as Greene's Creek in 2001, which is just downstream of the SE 148tb bridge. (see htto:llyour.kingcountv.gov/c!nrnllibrary/archive- Muckleshoot Indian Tribe Fisheries Division Comments to May Creek Dredging 401 c and CZM Public Notice documents/wlr/waterres/salmoniMaps/200 1I0205distroEASTlake W A.pdf). May 11, 2011 Page 5 The project also needs to mitigate for the loss of the full channel spanning pool at the Long Marsh Creek confluence, Tills pool will be eliminated by the stream dredging and not replaced based on the proposed mitigation plans. Since pools are limited in this portion of May Creek per the baseline stream conditions report, the pool should be replaced, potentially downstream of SE 148th adjacent to the NGPE tract for Stonegate where there are fewer constraints, . Alluvial fans are natural features at Long Marsh Creek and farther upstream at Indian Meadow Creek. According to the sediment assessment report, these features have been documented in the May Creek Valley since 1872. As a result, they will likely be continued sources of sediment to May Creek. Phase I and the future phases need to develop strategies that accommodate these natural features instead of proposing dredging now and into the future, The project may also aggravate existing conditions for water temperature and dissolved oxygen in May Creek, Currently May Creek through the May Valley is shown as a "Category 2" water for temperature and dissolved oxygen on Ecology's 2008 303(d) list. The removal of vegetation along 0.6 miles of May Creek that currently provides shade may worsen this condition. Once a redesigned project has been developed that addresses the concerns above, then a water quality protection plan and a monitoring plan that assesses the project's effects on sediment transport/filling, flooding, habitat creation and riparian planting success can be developed. Any approved project should be monitored for 10 years to determine project success (or failure) prior to allow any new dredging, I I ~ I EXHIBIT 24 US Army Corps of Engineers Seattle District Joint Public NotIce ~ IHlllifU tHll I ! , II 1 U E I I 0 f ECOLOGY Application for a Department of the Army Permit and a Washington Department of Ecology Water Quality .Certification and/or Coastal Zone Management Consistency Concurrence US Army Corps of Engineers Regulatory Branch Post Office Box 3755 Seanle, Washington 98124-3755 Telephone (206) 766-6438 Attn: Lori C. Lull, Project Manager W A Department of Ecology SEA Program .. Post Office Box 47600 Olympia, Washington 98504-7600 Telephone (360) 407-6068 Attn: SEA Program, Federal Permit Coordinator Public tice at.: 24 Septem Expira . n Dat : 24 October 20 Referen e No.: Name: ing Coun.J,,=v--' Interested parties are hereby notified that the u.s. Army Corps of Engineers (Corps) and the Washington Department of Ecology (Ecology) have received an application to perform work in waters of the United States as described below and shown on the eoclosed drawings. The Corps will review the work in accordance With Section 404 of the Clean Water Act (CWA). Ecology will review the work pursuant to Section 401 of the CW A, with applicable provisions of State water pollution control laws and the Coastal Zone Managemeot Act. APPLICANT: King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, Washington 98104-3855 Attention: . Doug Chin Telephone: (206) 296-8315 LOCATION: In May Creek aiJd wetlands abutting May Creek at Renton, Washington WORK: The work includes removal of sedimeot from 2,000 linear feet of May Creek and clearing of reed canarygrass and willows from 8500 square feet of the May Creek channel. Sediment removal will be done with a trackhoe or similar equipmeot. A portion of material removed from the streambed will be stockpiled, dried, and spread in adjaceot upland horse pastures. Excess sedimeots and material that is removed with reed canary grass will be disposed of off site at an undetermined upland location. Construction impacts will also include placement of quarry spalls in approximately 7550 square feet of wetlands for a temporary access road; After construction is complete (approx. 10 days), this fill will be removed and the area will be replanted with native vegetation . . MITIGATION: The applicant has proposed mitigation to offset negative impacts to in-stream fish habitat. The mitigation includes a 15 foot buffer of native riparian and wetland planting on both sides of May Creek (1.3 acres), enhancemeot of3.75 acres of wetland on the west side of 148th Aveoue Southeast, which includes excavation and placement of streambed gravel in approximately 0.7 acre along the channel of May Creek to create off-channel NWS-2010-158 alcoves. If an easement is granted, mitigation will also include excavation and placement of streambed gravel and Large Woody Debris, impacting 150 linear feet at the confluence of Long Marsh Creek and May Creek. PURPOSE: The applicant has stated that the purpose is to reduce the duration of flooding in pastures on rural residential properties. ENDANGERED SPECIES: The Endangered Species Act (ESA) requires federal agencies to consult with the National Marine Fisheries Service (NMFS) andlor U.S. Fish and Wildlife Service (USFWS) pursuant to Section 7 of ESA on a1l actions that may affect a species listed (or proposed for listing) under the ESA as threatened or endangered or any designated critical habitat. After receipt of comments from this public notice, the Corps will evaluate the potential impacts to proposed and/or listed species and their designated critical habitat. ESSENTIAL FISH HABITAT: The Magnuson-Stevens Fishery Conservation and Management Act, as amended by the Sustainable Fisheries Act of 1996, requires all Federal agencies to consult with the NMFS on all actions, or proposed actions, permitted, funded, or undertaken by the agency, that may adversely affect Essential Fish Habitat (EFH). The proposed action would impact EFH in the project area. If the Corps determines that the proposed action may adversely affect EFH for federally managed fisheries in Washington waters, the Corps will initiate EFH consultation with the NMFS. The Corps' final determination relative to project impacts and the need for mitigation measures is subject to review by and coordination with the NMFS. CULTURAL RESOURCES: The District Engineer has reviewed the latest published version of the National Register of Historic Places, lists of properties determined eligible and other sources of information. No known historic properties occur in the vicinity of the proposed project. Due to the project's location in the landscape (i.e. adjacent to a river), there is a high likelihood that unknown historic properties occur in the project area. An historic properties investigation may be required during the permit review. The District Engineer invites responses to this public notice from Native American Nations or tribal governments; Federal, State, and local agencies; historical and archeological societies; and other parties likely to have knowledge of or conccms with historic properties in the area. This public notice initiates consultation under Section 106 of the National Historic Preservation Act with any Tribe that has information or concerns with historic properties in the proposed permit area. EVALUATION CORPS: The decision whether to issue a permit wi1l be based on an evaluation of the probable impacts, including cumulative impacts, of the proposed activity on the public interest. That decision will reflect the national concern for both protection and utilization of important resources. The benefits, which reasonably may be expected to accrue from the proposal, must be balanced against its reasonably foreseeable detriments. All factors which may be relevant to the proposal will be considered, including the cumulative effects thereof; among those are conservation, economics. aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood haZards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, considerations of property ownership, and, in general, the needs and welfare of the people. The Corps is soliciting comments from the public; Native American Nations or tribal governments; Federal, State, and local agencies and officials; and other interested parties in order to consider and evaluate the impacts of this activity. Any comments received will be considered by the Corps to determine whether to issue, modifY, condition or deny a permit for the work. To make this decision, comments are used to assess impacts on endangered species, historic properties, water quality, general environmental effects, and the other public interest factors listed above. Comments are used in the preparation of'an Environmental Assessment andlor an Environmental Impact Statemelit pursuant to the National Environmental Policy Act. Comments are also used to determine the need for a public hearing and to determine the overall public interest of the activity. 2 ---, .. _--------------- NWS-2010-158 The described discharge will be evaluated for compliance with guidelines promulgated by the Environmental Protection Agency under authority of Section 404(b)( I) of the CW A_ These guidelines require an alternatives analysis for any proposed discharge of dredged' or fill material into waters of the United States_ EVALUATION-ECOLOGY: Ecology is soliciting comments from the public; Federal, Native American Nations or tribal governments, State, and local agencies and officials; and other interested parties in order to consider and evaluate the impacts of this activity. Ecology will be considering all comments to determine whether to certifY or deny certification for the proposed project. COMMENT AND REVIEW PERlOD: Conventional mail or e-mail comments on this public notice will be accepted and made part of the record and will be considered in determining whether it would be in the public interest to authorize this proposal. In order to be accepted, e-mail comments must originate from the author's e- mail account and must include on the subject line of the e-mail message the pennit applicant's name and reference number as shown below. Either conventional mail or e-mail comments must include the penn it applicant's name and reference number, as shown below, and the commcnter's' name, address, and phone number. All comments whether conventional mail or e-mail must reach this office, no later tluu:l-t~p; date of this public notice to ensure consideration. ' Corps Comments: All e-mail commentsshouldbesentolorLc.lull@usace.army.mil. Con ntional mail comments should be sent to U.S. Army Corps of Engin ers, Regulatory Branch, Attentio . Lori C. Lull, Post Office Box 3755, Seattle, Washington, 98124-3755. Ecology Comments: Any person desiring to present views on the project pertaining to a request for water quality certification under Section 401 of the CW A and/or Coastal Zone Management consistency concurrence, may do so b -submmmg written com to the following address: Department of Ecology, Attention: SEA program- Federal Permit Coordinator, Post ffice Box 47600, Olympia, Washington, 98504-7600, or e-mail to ecyrefedpermits@ecy.wa.gov To ensure proper consideration of all comments, responders must include the following name and reference number in the text of their comments: King County (May Creek); NWS-2010-158 Encl: Figures (8) 3 --------- I I I I I I I I I I I I I I I I I I I Appendix A. May Creek Channel Restoration photograph log. Photo perspective is looking upstream unless otherwise noted. Left bank is on the left side when facing downstream. Photo I . Entrance to forest at downstream end of survey; perspective is looking downstream. Photo 2. Cobbles in forested area. Photo 3 . Perspective is looking downstream. Photo 4. No woody riparian plants . Photo 5 . Photo 6. Greenes Creek. Photo 7. Greenes Creek. No surface flow to May Creek but greener grass probably marks subsurface route. Photo 8. Buck rub on willow . Photo 9. Photo 10. Perspective is looking downstream. Photo 11. Photo 12. Willows provide cover and in-stream structure. I I I I I I I I I I I I I I I I I I I I I I I I I Photo 13. Photo 16. Newly plant ed spruce on left bank open space property. I I I I I Photo 14 . Photo 17. I I I I I Photo 15. Photo 18 . Ponded water down stream of I 148 th Ave SE bridge . I I Photo 19. 148 Lh Ave SE bridge. Photo 20 . 148 Lh Ave SE . Photo 21. Looking down stream under 148 Lh Ave SE bridge. Photo 22. Upstream of 148 Lh Ave SE bridge . Photo 23. Photo 24. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I '.' , . .. .~ " • f4:" .,. • i \ ,~~',. .-\~ \" . ~-. .. '('",. ,,' '" lo. ,. ., 'eli , \ "S. \ ~ '. -\ • , \ Photo 25 . Photo 26, Another buck rub on willows. Photo 27. Photo 28. Photo 29, Photo 30, Confluence of Long Marsh Creek, Photo 31 . Footbridge over May Creek near Long Marsh Creek. Photo 32. Looking upstream at Long Marsh Creek confluence. Gravels at confluence. Photo 33. Photo 34 . Photo 35 . Photo 36. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 37. Long Marsh Creek, looking up the chan nel from May Creek. Photo 38. Looking down May Creek from Long Marsh Creek. Photo 39. Narrow alder riparian corridor up stream of Long Marsh Creek confluence. Photo 40. Right bank armor. Photo 41. Photo 42. Pasture on left bank. Photo 43. View of right bank. Photo 44. Horse in right bank pasture. Photo 45. Flooded left bank pasture. Photo 46 . End of woody riparian corridor. Photo 47. Photo 48. Flooded left bank pasture flowing into May Creek . I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 49 . Flooding adjacent to May Creek. Photo 50 . Looking upstream toward Red Bam. Photo 51 . Looking downstream. Photo 52. Flooding along both banks of May Creek. Photo 53. Photo 54. Flooded lJasture near Red Bam. Photo 55. Photo 56. May Creek channel near Red Bam. Photo 57. Photo 58. Looking downstream from near Red Bam. Photo 59. Muddy pasture on left bank. Photo 60. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 61 . Photo 62. Red Barn driveway bridge across May Creek, looking south. 21111 O. Photo 63. Looking toward May Creek on 3/ I / I O. Indian Meadows Creek is in ditch. Photo 64. Indian Meadows Creek culvert outlet. Excavated gravels are piled on banks. Photo 65. Indian Meadows Creek culvert outlet. Photo 66. Indian Meadows Creek looking toward May Creek . All gravels are deposited in this reach . Photo 67. Indian Meadows Creek, looking upstream from May Creek. All gravels are deposited in short reach indicated by arrow. Stream substrate is fines below lower culvert. Photo 68. Confluence of Indian Meadows Creek with May Creek, 3/1/10. Minimal sediment deposition at confluence: May Creek is more than a meter (3 It) deep . I I I I I I I I I I I I I I I I I I I I I I I I I I I 'I I I I I I I I I I I 6 References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. King County 1990. Sensitive Areas Map Folio. King County. 1995. May Creek Current and Future Conditions Report. King County. 2001. Final Adopted May Creek Basin Action Plan. King County. 2010. May Creek Hydraulic Study (Draft). Snyder, D.E., P.S. Gale, and R.F. Pringle. United States Department of Agriculture, Soil Conservation Service. 1973. Soil Survey, King County Area, Washington, Sheet Number 5. .Washington Department of Fisheries. 1975. A Catalogue of Streams and Salmon Utilization. Volume I. Olympia, Washington. May Creek Channel Restoration Baseline Stream Conditions Page 6-17 5 Discussion May Valley has historically been an area of floodwater and sediment storage. The nearly flat stream historically braided through extensive wetlands. The channel was ditched between 1910 and 1936 for agriculture (King County 1995). The ditched channel filled with sediment and was dredged by King County in the 1940's to reduce flooding, and refilled with sediment again by the 1960's (King County 1995). Heavy truck farming was taking place in the valley during this time, and agricultural fields were plowed right up to the top of the stream banks (King County 1995). Sediment sources to May Creek in May Valley have not been clearly identified. The May Creek Erosion Stabilization Draft Report (Anchor QEA, LLC 2010) only addresses erosion downstream of May Valley. The flat valley reach may not have enough power to transport sediment nearly two miles from upstream sources to the project area, and large sediment plumes from tributaries were not observed during site visits. Gravel transported to May Creek from Long Marsh Creek creates one of the few potential spawning areas within the project area, and did not appear to hinder water flow during the site visit. Gravels in Indian Meadow Creek that are removed from the channel before they reach May Creek could provide additional spawning habitat. While erosion in the May Canyon is an ongoing problem, the May Creek Hydraulic Study (King County 2010), which evaluates several alternatives for dredging in the valley, shows that there is no substantial difference in the erosion that occurs in the canyon under existing conditions and erosion that would occur under any of the proposed dredging alternatives. If dredging is proposed in areas of the valley that are designated as open space, where flooding does not threaten homes or pastures, and where an intact woody riparian corridor provides better fish habitat, mitigation would likely be required to offset the negative affects that the dredging would have on fish habitat. These existing areas may provide pockets of refuge for rearing and migrating fish, and may provide such refuge for fish affected by dredging in the valley. The proposed project is one off our proposed "Insufficient Flow Projects" identified in the May Creek Drainage and Restoration Plan (GeoEngineers 2008). The four projects together would result in the dredging of about 3.64 km (2.26 miles) of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. May Creek Channel Restoration Baseline Stream Conditions Page 5-16 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I and in May Canyon; they most likely do not travel upstream as far as May Valley (King County 1995). Coho salmon and rainbow/steelhead and cutthroat trout rear in May Valley and use it as a travel corridor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 0291A (King County 1995). Stormwater stored in May Valley helps maintain spawning and rearing habitat downstream, especially in May Canyon. Floodwaters stored in the valley are released slowly and are thus less likely to scour redds in spawning beds in the canyon. Slow release of stormwater from the valley also probably decreases the potential erosion of canyon walls from storm flows. May Creek is located in Watershed Resource Inventory Area (WRIA) 8: Lake Washington Basin. It is a King County Critical Areas Ordinance Class F (fish present) stream, with 50.3 m (I 65-ft) regulatory buffers. Puget Sound Chinook salmon and steelhead are listed as threatened under the Federal Endangered Species Act. May Creek Channel Restoration Baseline Stream Conditions Page 4-15 this area is likely a result of sediment that was removed by King County in 2002 as part of a channel obstruction removal pilot project. Long Marsh Creek enters May Creek on the right bank at about RK 7.44 (RM 4.62, Figure 3). This tributary is a source of gravels to May Creek and there is about a 20 m (65 ft) section of stream with spawning-sized gravels around the stream confluence (Appendix A, Photos 30, 32, 37, 38). Reach Four. End of woody riparian corridor (about RK 7.6 [RM 4.7]) to Red Barn (about RK 7.9 [RM 4.9]). The riparian corridor in Reach Four consists almost entirely of reed canarygrass. The channel is straight, narrow, and deep, and has less capacity to contain water than the other reaches. Wetted channel width is about 4m (13 ft), wetted depth is about l.3m (4.3 ft), and fine sediment deposited on the channel bottom is 0.3 to 0.5m (I to 1.6 ft) deep. During the February 1,2010 site visit, pastures on both banks of the stream were flooded. It was not clear whether the flooding was entirely a result of overbank flow from May Creek, or whether a combination of overbank flow and high groundwater level. It appears that the valley slopes slightly to the north in the study area. Water from the flooded pasture on the left bank was flowing into May Creek at the time of our survey, and overbank flow from May Creek seemed to be flooding the pasture on the right bank (Appendix A, Photo 48). It was difficult for us to identify the May Creek channel in some of the flooded areas, and we could not find the confluence of Indian Meadow Creek, so we were unable to evaluate sediment inputs from this tributary. It also looked as though erosion from muddy horse pastures upslope of May Creek may possibly contribute some sediment to the stream. During a follow-up site visit on March 1,2010 we were able to identify the Indian Meadow Creek confluence with May Creek (Appendix A, Photos 63 to 68). This stream drains Grand Ridge on the north side of May Valley and is piped and channelized along a private driveway before entering the right bank of May Creek at about RKM 7.85 (4.88, Figure 3). Substrate in the flat, unpiped portions of this stream consisted of spawning- sized gravels that are routinely removed from the channel prior to reaching May Creek (Appendix A, Photos 64, 65, 67). A small deposit of fine sediment from Indian Meadow Creek is present in May Creek at the confluence, but the sediment does not appear to have much effect on the channel's capacity to contain flow. 4.3 Fish Habitat and Use May Creek historically was an important salmon stream in the Lake Washington Basin (WDF 1975). The stream supported five species of salmonids: Chinook (Oncorhyncus Tschawytscha), sockeye (0. nerka), and coho (0. kisutch) salmon, and rainbow/steelhead (0. mykiss) and cutthroat (0. clarki) trout (King County 1995). Salmon still use the stream and its tributaries even though their numbers have decreased (King County 1995). Chinook and sockeye salmon are found in the lower reaches of May Creek May Creek Channel Restoration Baseline Stream Conditions Page 4-14 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Interspersed among the willow-dominated areas are a few stretches of stream with no woody riparian plants (Figure 3). The riparian corridor in these areas is dominated by reed canarygrass. Flow is uniformly slow and deep, with deep accumulations of fine sediment. Wetted width is about 4 m (13 ft), wetted depth is about 1.5 m (4.9 ft), and fine sediment accumulation is about 0.5 m (1.6 ft). These stretches of stream are less structurally complex than the willow-dominated areas, and reed canarygrass is the primary influence on in-stream fish habitat. Although reed canarygrass-dominated slow water, uniform, channels provide limited habitat for most species of salmon ids, these areas do provide good rearing habitat for coho salmon fry because the grass slows the water current and provides hiding cover and shade. The channel becomes wider and shallower, and accumulations of fine sediment disappear near the entrance to the forested riparian corridor (Figure 3). Wetted channel width is about 5.8 m (19 ft), wetted depth is about 0.5 m (1.6 ft), and 2 to 5-cm (I to 3- inch) clean, loose gravels dominate the substrate, with some cobbles present along the channel edges. Red alder, willows, Indian plum, sword fern, and reed canarygrass are dominant riparian vegetation. The forested reach may provide some spawning habitat for coho salmon and trout, as well as rearing habitat. We observed Greenes Creek during a second site visit on March 1,2010, when the May Creek stream level was substantially lower than on the February 1,2010 (Appendix A, Photo 6). Greenes Creek flows from the East Renton Plateau toward the left (south) bank of May Creek at about RKM 7.0 (RM 4.4, Figure 3). The creek did not enter May Creek at the time of the site visit, but instead dissipated and infiltrated in the adjacent wetland (Appendix A, photo 7). We saw no sediment deposition from Greenes Creek in either the wetland or in May Creek. Reach Two: 148 th Ave SE bridge (about Rkm 7.8 [RM 4.46]) upstream to Fence line (about RK 7.3 [RM 4.55]). This reach has a relatively wide, mature willow-dominated riparian corridor. In-stream habitat is mixed riffle and glides or pools. Substrate is dominated by accumulations of fine sediments. This reach is well-connected with its floodplain. We observed evidence of recent overbank flooding and flood storage in the riparian corridor. We saw a second buck rub on a willow in this reach (Appendix A, Photo 26). Reach Three: Fenceline (about RK 7.3 [RM 4.55]) upstream to End of woody riparian corridor (about RK 7.6 [RM 4.7]). Willows are absent and the mature red alder- dominated riparian corridor is much narrower, about three meters (lOft) wide, in Reach Three. Reed canarygrass dominates the understory, and horse pastures are present on both sides of the stream. The wetted channel width is about 6.4 m (21 ft) and the wetted depth is about 0.9 m (3.0 ft), substrate is mostly fine sediment. The horse pasture on the right bank is about a meter (3 to 4 ft) above the current water surface, suggesting that the channel in this reach is currently large enough to transport higher flows than those present during our survey (Appendix A, Photo 44). The increased channel capacity in May Creek Channel Restoration Baseline Stream Conditions Page 4-13 May Creek Channel Restoration Project Stream Features • Study Area o River Mile /'-/ Streets /'-/ Streams Incorporated Areas Cougar Mountain Wildland Park t~ N i- March 2010 U1 King County o;. .. m .... 'w~=====~=-O ...... ~-=======~~O • Feet The information induded on .,.. map has been compi.d by King Count)' staff from a vanity of sources tnd is tobjed to change wthout notice. King County makes no representations otw.~nliel. upr ••• or impied , as 10 acaney, completen •• , timtlness, or rights 1:0 h use of Iil.IdI informatIOn. This dowment is not nended fof use a. I ........ , prodUd ~ COunl)' shall not be li ablt for Iny pneral, special, ndirect. inOdenlal, or consequential darr.g •• lnduding, but not limited to,to. revenues or bs1 profit , r'lUlting from the use or misuse of ... infofmrlion com.ned on this map Ally sale of this map or infOlmaOon on this map is prohIbited except by written permISsion of King County Figure 3 n .... _aeo.·e ...... ,._ ......... :JIS.a." --., ... ,.. •• _. (II_\lCD_.GIC , channel fonn appears to be mostly forced pool riffle. In areas where riparian vegetation consists of reed canarygrass or trees high on the banks, the channel fonn appears to be plane-bed. Both channel fonns derive from past excavations and ditching for agriculture and sediment deposition. The channel gradient is flat throughout. The water was too high for us to see the banks in most locations. Where banks were visible, stability looked good. The King County Area Soils Survey maps soils in May Valley as mostly Alderwood and Bellingham soils. Alderwood soils fonned in glacial deposits, and Bellingham soils fonned in alluvium found mostly in depressions in glacial deposits (Snyder et al. 1973). We did not sample soil during site visits, but soils observed in soil pits during the wetland delineation will be described under separate cover. 4.2 Stream Habitat We could not wade most of the stream reach during the February 1,2010 survey because the water was too.deep. Most observations and limited measurements were made while standing on the banks. In-stream habitat in the surveyed reach of May Creek is greatly influenced by riparian plant communities. Aquatic habitat is much more complex in places where the riparian corridor has woody plants, such as willows, actively engaged with the stream channel and connected floodplain. Overhanging or rooted willow branches or stems provide cover and hard points necessary for bedfonn complexity, producing both turbulent and non-turbulent flow areas, backwaters and riffles, and shade and nutrients during the summer (Appendix A, photos 9, 12, 14,23,25). Areas with no woody riparian plants are much more unifonn and tend to have accumulations of fine sediments in the channel (Appendix A, Photos 4, 5,10, II, 13,47,50 to 58, 60, 61). We divided the surveyed portion of May Creek into four reaches based mostly on the nature of the riparian corridor (Figure 3). These reaches are described in greater detail below. Reach One: Edge offorest (about RK 6.97 [RM 4.33}) to 148 th Ave SE bridge (about RK 7.18 [RM 4.46]). The effect of riparian plant communities is pronounced in Reach One. Most of the reach has a mature willow-dominated riparian corridor, with reed canarygrass dominating the understory. Abundant lichens grow on willows, suggesting they've been there awhile. Wetted channel width is 10 to IS m (32 to 49 ft). Substrate consists mostly of fine-grained sand and silt, but some small gravels (2 to 5-cm [I to 2- inch 1 size) are exposed in fast water areas. As described above, overhanging and rooted willow branches and stems provide cover and hard points to create complex in-stream aquatic habitat. Water is clear and cold. The mixture of slow water and fast water habitats and abundant cover provide good rearing habitat for coho salmon and trout. We also saw a buck rub on a willow in this reach (Appendix A, Photo 8). The channel is well connected with its floodplain, and the reach provides good flood storage. May Creek Channel Restoration Baseline Stream Conditions Page 4-11 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 4.1.2 Riparian Land Use and Vegetation Small horse farms and open space are the primary land-uses in May Valley. Wetlands that have been converted to horse pastures border both sides of the stream in the project reach, except for the area downstream of 148 th Ave SE, which is open-space associated with the Stonegate development (Figure 3). Reed canarygrass (Phalaris arundinaceae) is pervasive. Stands of willow (Salix spp.) and red alder (Alnus rubra) in the downstream portion of the project reach greatly improve the stream channel from a habitat and natural channel morphology perspective. These woody plants stabilize stream banks, provide shade, food, and hiding cover, and affect in-stream habitat by providing hard points that create a mixture of slow-water and fast water areas. The channel in the upstream portion of the project reach, which lacks woody plants and is almost exclusively vegetated with reed canarygrass, is more uniform and has filled in with sediment so it is more prone to flooding. Sources of this sediment are unclear. It may be deposited by tributaries and stored in the valley, or it may be eroded from surrounding horse pastures, deposited in the stream channel, and stored in the valley. Horse pastures in the vicinity of the filled-in channel sections slope toward the stream and are muddy throughout much of the year (Appendix A, Photos 42, 44, 56, 59, 64, 67). 4.1.3 Adjacent Wetlands Wetlands are present along May Creek through most of the project area. Many wetlands have been converted to horse pastures and will be described in more detail under separate cover. Dominant vegetation is reed canarygrass. We saw both resident and migratory waterfowl using the open water wetland on the south side of May Creek, including mallards (Anas platyrhynchos), American widgeon (A. Americana), and wood ducks (Alx sponsa). 4.1.4 Animal Habitat and Use May Creek and associated wetlands provide habitat for a wide variety of animal species. Although we did not see terrestrial wildlife during site visits, we can assume that the following species use habitats within the study area: deer, bobcat, coyote, raccoon, moles, voles, and mice, as well as waterfowl and songbirds. We saw two buck rubs on willows adjacent to the stream; one rub was downstream of the l48th Ave SE bridge, near RM 4.4, and one rub was upstream of the bridge, near RM 4.5. We saw both resident and migratory waterfowl in the open water wetland on the south side of May Creek near RM 4.75, including mallards, American widgeon, and wood ducks. Fish, salamanders, frogs, and crayfish, are probably present in aquatic habitats within the proposed project area. 4.1.5 Riparian Soils, Bank Stability, and Channel Morphology From our vantage on the streambanks, it looked as though the project reach of May Creek has two primary channel forms, which are dependent on the riparian plant community. In areas where willows are present and in contact with stream flow, the May Creek Channel Restoration Baseline Stream Conditions Page 4-10 Bellenle Bellenle Ne\\castle Issaquah !I! ~ J W J o . \ ~ EAsr \ " \ ):!NJ~~ Renton • ,. May Creek Channel Restoration Project Ma y Creek Basin • Study Area 0 River Mile /"-V Streets /"-V Streams 50 Foot Contours o May Creek Basin • Water Features ~ Wetlands (N WI) Incorporated Areas Cougar Mountain Wildland Park ~ ~ N -(- March 2010 ~ King County o 900 1,800 3,600 5,400 The information induded on lhisTrlap has been compiled by ~ng County staft"from a variety of sources and is subject to eIlange w~hout notea. King County makes no representations or wilrTOIInties, express or imp(ed . as 10 .cw~cy. completeness , limeiness, or rights to the use of $Oat information . This dowment i$nol mended for usa ilS I survey product . King County shan not be liable for any general . special, ndirect, inadental, or consequential damages induding, but not limited to ,/ost revenues or bst pro6ts resulling from the use or misuse of the information contaned on this map. My sale of lhi , map or information on this map is prohiMed except by written permission of King County. Figure 2 7 .. __ ~I:'OII'·e ''''.'I_'''''''''':II5_'.I'.' .... C .. IIIt .tI_. ~ • .,a._IGC 4 Existing Conditions 4.1 General Site Survey The general site survey is qualitative, based on information obtained through review of existing background information and observations made during site visits. Results of the general site survey should not be viewed as a systematic, quantitative evaluation of the features described. . 4.1.1 Natural Drainage System May Creek is about 11.3 kilometers (seven miles) long, with about 30.6 km (19 miles) of tributary streams, draining about 38.3 square kilometers (14 square miles) in eastern King County (Figure 2, King County 1995). Three headwater creeks join at the top of May Valley to form the main channel, which flows through the valley and a narrow, erosive canyon before flowing into Lake Washington (Figure 2). The bedrock foothills of Cougar Mountain, Squak Mountain, and Newcastle Hills form the uplands north of May Valley, and a gently rolling plateau of glacial deposits (East Renton Plateau) forms the uplands south of May Valley (King County 1995). The valley itself was carved by glacial meltwater, and is underlain by 61 to 152 meters (200 to 500 feet) of unconsolidated glacial sediments (King County 1995). Tributaries descending through the glacial deposits of the plateau to the south and across the steep bluffs of the canyon are highly erosive and contribute large amounts of sediment to May Creek, whereas tributaries descending from the bedrock-underlain foothills to the north of May Valley are less erosive (King County 1995). May Valley was historically an area of sediment deposition and flood storage, and the stream channel braided through extensive wetlands. The stream was put in a ditched single-strand channel so the surrounding floodplain could be used for agriculture. Stormwater storage in May Valley is important for controlling erosion in May Canyon, which is experiencing severe erosion in both the mainstem and tributaries (King County 2001, Anchor QEA 2010). Much of the sediment plume deposited by May Creek in Lake Washington is probably a result of canyon erosion, since sediment is stored in May Valley (King County 1995). May Creek Channel Restoration Baseline Stream Conditions Page 4-8 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 3 Methods 3.1 Literature Review We reviewed the following information to identify natural drainage system features and provide background information prior to field visits: • May Creek Current and Future Conditions Report, March 1995. King County Surface Water Management Division; • May Creek Basin Action Plan, April 2001. King County Department of Natural Resources, Water and Land Resources Division; • May Creek Drainage and Restoration Plan, December2008. GeoEngineer; • May Creek Erosion Stabilization Draft Report, May Creek Sediment Transport Study Phase 3, January 2010. Anchor QEA, LLC; • Washington Department of Fisheries. 1975. A Catalogue of Streams and Salmon Utilization. Volume 1. Olympia, Washington; • Snyder et al. 1973. Soil Survey of King County Area, Washington. Soil Conservation Service; • King County Sensitive Areas Map Folio. 1990. Maps 4 (Duwamish) and 9 (Issaquah). 3.2 Field Methods On February 1,2010 King County Roads Environmental Unit Senior Ecologists Erick Thompson and Kerry Bauman walked about 853 meters (2,800 feet) of May Creek, beginning about.100 meters (328 feet) downstream of 148'h Ave SE, near river kilometer 7.0 (river mile 4.35), and proceeding upstream to the "red barn" at about river kilometer 7.8 (river mile 4.87, Figure I). We walked May Creek to visually characterize channel morphology, bank condition, substrate, in-stream aquatic habitat, large wood, and riparian plant communities and land-uses. We measured wetted channel width and depth in representative locations, but high water prevented identification ofbankfu1 channel width and dep!h. We used field observations to characterize the present condition of the stream channel, including its suitability as fish habitat and its apparent conveyance capacity for water and sediment. We also noted any fish, other aquatic organisms, and wildlife or wildlife signs we noticed during the survey, and took photographs to provide a visual record (Appendix A). May Creek Channel Restoration Baseline Stream Conditions Page 3-7 May Creek Channel Restoration Project Proj eel Vicinity • Study Area o Mile Markers • Stream Incorporated Areas Cougar Mountain Wildland Park ( ... N + March 2010 ~ King County o 95 190 380 570 ..................... _ .. IN,"'.~_-... • .., I4r1tC~ ... "-.......... M_.,.,.ir:S ....... " .................. I411fC~ __ ... , ...... _ .... _"..-..... , ........... _IIOI!f;-. ....... IirMIIII_.1itt* ....... 4 ..... --.... ... M ............. """'*' ........ .., ..... ,. ..... ~C ___ IfI._ .. Wt .................. ,..... ~ct..,.d ...... ., ........ ~ __ .IrI ....... _ .. I ......... Ien_ .. "'" .... _ ....... ... ..... "* .... tI.IMo ....... ~ ........... . ",., ....... ""' .. IfrIt,...,.." ......... , .... ~ _"'.., .... ,. ........ ~c ... Figure 1 r----... ---------------- 2 Introduction King County Department of Natural Resources and Parks, Water and Land Resources Division (KC DNRP) proposes to remove sediment and in-channel plants from May Creek within May Valley to increase channel conveyance capacity and reduce flooding to adjacent pastures. A total of four "ineffective flow" channel clearing projects were proposed in the May Creek Drainage and Restoration Plan, totaling about 3.64 kilometers (2.26 miles, GeoEngineers 2008), which is about 75% of the total length of May Creek in May Valley, and about 32% of the total seven-mile length of May Creek. We studied existing conditions on about 853 meters (2,800 feet) of May Creek, beginning about 100 meters (328 feet) downstream of l481h St, near river kilometer 7.0 (river mile 4.35), and ending near river kilometer 7.8 (river mile 4.87), and roughly corresponding to the area of May Creek identified in "Ineffective Flow Project # I" (GeoEngineers 2008, Figure I). Our study evaluates the suitability of the stream as fish habitat, and physical processes affecting the stream, stream channel, and stream inhabitants. Included in the study is a review of existing literature and information about May Creek, and a qualitative general site survey which evaluates the physical and biological characteristics of the channel and the surrounding areas. May Creek Channel Restoration Baseline Stream Conditions Page 2-5 ---·---l I I I I I I I I I I I I I I I I I I I .1 I I I I I I I I I I I I I I I I I I I Key Points: I. May Valley was historically an area of floodwater and sediment storage as the nearly flat stream braided through extensive wetlands. The channel was ditched between 1910 and 1936 for agriculture (King County 1995). The ditched channel filled with sediment and was dredged by King County in the 1940's to reduce flooding, and refilled with sediment again by the 1960's (King County 1995). Truck farming was taking place in the valley during this time, and agricultural fields were plowed right up to the top of the stream banks (King County 1995). 2. Current sediment sources to May Creek in May Valley have not been clearly identified. The May Creek Erosion Stabilization Draft Report (Anchor QEA, LLC 2110) only addresses erosion downstream of May Valley. It is unclear if flows in the flat valley reach have enough power to transport sediment the nearly two miles from upstream sources to the project area, and large sediment plumes from tributaries were not observed during site visits. Gravel transported to May Creek from Long Marsh Creek creates one of the few potential spawning areas within the project area, and did not appear to hinder water flow during the site visit. Severe erosion is present in a canyon reach below the project area (King County 1995, Anchor QEA 2010). The May Creek Hydraulic Analysis (King County 2010) evaluated whether dredging in the valley would worsen erosion in the canyon. This analysis showed that there is no substantial difference between the erosion that occurs in the canyon under existing conditions and the erosion that would occur under any of the dredging alternatives. 3. Areas of the valley that are designated as open space, where flooding does not threaten homes or pastures, and where an intact woody riparian corridor exists provide pockets of refuge for rearing and migrating fish. If left intact, these areas may provide refuge for fish affected by dredging in the valley. 4. The proposed project is one of four proposed "Insufficient Flow Projects" identified in the May Creek Drainage and Restoration Plan (GeoEngineers 2008). The four projects together would result in dredging of about 3.64 km (2.26 miles) of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. May Creek Channel Restoration Baseline Stream Conditions Page 1-4 1 Summary King County Department of Natural Resources and Parks proposes to dredge portions of May Creek in the May Valley to increase channel capacity and reduce flooding to adjacent pastures. The stream in this area is nearly flat and flows through large wetlands. many of which are currently used as pastures for horses. Historically, May Valley provided floodwater storage for tributaries draining the upper May Creek basin. Limited capacity to transport sediment through the flat valley allowed sediment to accumulate. Land owners periodically cleared the stream of sediment and in-channel plants until about the 1940's (King County 1995). Since then, development in the upper watershed to the north and south of May Valley has increased storm water run-off, leading to an increase in the frequency and duration, but not magnitude, of flooding in May Valley (King County 1995). Some infilling of the May Creek channel by fine sediment mobilized during flooding has probably contributed to increased flooding in the valley. Chronic winter flooding of some properties in May Valley limits the use of these properties for pasture and grazing oflivestock, mostly horses. Stream baseline conditions were determined on about 853 meters (2,800 feet) of May Creek, beginning about 100 meters (328 feet) downstream of 148 th Ave SE, near river kilometer 7.0 (river mile 4.35), and ending near river kilometer 7.8 (river mile 4.87). In the proposed project area, May Creek flows through a flat, formerly ditched channel in an oversized valley formed by glacial meltwater (King County 1995). The valley is bordered on the north by Cougar and Squak mountains, which are underlain with bedrock, and on the south by the East Renton Plateau, which is formed by glacial deposits. The flat May Valley reach of May Creek stores stonnwater and sediment, slowly releasing both to a steep, erosive canyon section downstream of the study reach, Slow water and abundant cover from overhanging vegetation in the study reach provide rearing and refuge habitat for coho salmon, cutthroat trout, and rainbow/steelhead trout. These fishes also use the mainstem creek as a migration corridor to spawning and rearing habitat in tributaries such as the North Fork, Cabbage Creek, Country Creek, and Tributary 0291A. Stormwater and sediment storage in the valley also help maintain spawning and rearing habitat for salmon in May Canyon, located immediately downstream of May Valley. Five species of salmon are found in May Canyon: Chinook, sockeye, and coho salmon, and cutthroat and rainbow/steelhead trout (King County 1995). Puget Sound Chinook salmon and steelhead are listed as threatened under the Federal Endangered Species Act. If the proposed project requires a federal permit or has federal funding, then endangered species act consultation for Chinook salmon and steelhead will be necessary. May Creek Channel Restoration Baseline Stream Conditions Page 1-3 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Table of Contents I Summary .................................................................................................................. 1-3 2 Introduction .............................................................................................................. 2-5 3 Methods .................................................................................................................... 3-7 3.1 Literature Review ............................................................................................. 3-7 3.2 Field Methods .................................................................................................. 3-7 . 4 Existing Conditions .................................................................................................. 4-8 4.1 General Site Survey ........................................................................................ .4-8 4.2 Stream Habitat ............................................................................................... 4-11 4.3 Fish Habitat and Use ...................................................................................... 4-14 5 Discussion .............................................................................................................. 5-16 6 References .............................................................................................................. 6-17 List of Figures Figure I. Vicinity Map .................................................................................................... 2-6 Figure 2. May Creek Drainage Basin ............................................................................ .4-9 Figure 3. Stream Features ..................................................................... .4-14 Appendix A: Photos May Creek Channel Restoration Baseline Stream Conditions Page 1-2 I I I I I I I I I I I I I I I I I I I EXHIBIT 12 BASELINE STREAM CONDITIONS MAY CREEK CHANNEL RESTORATION CIP#9A1205 April 15, 2010 U1 King County Prepared by: Erick Thompson Environmental Scientist III and Kerry Bauman Environmental Scientist III Department of Transportation Roads Services Division Environmental Unit 201 South Jackson Street, Suite 200 Seattle, Washington 98104 -------------------- May Creek Channel Restoration Project King County Water and Land Resources Division City of Renton Wetlan~i~ating Addendum to Wetland Delineation Report Dated M~~K 'fO~9/10 nnmg 0-_ on IVISion AUG ~ 5 ' <'01/ ~ IE ©IEUfJflEflJJ Prepared for: King County Department of Parks and Natural Resources Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 Prepared by: Cindy Clark, Environmental Engineer King County Road Services Division Environmental Unit November 17, 2010 CITY OF RENTON WETLAND RATING This document is an addendum to the May Creek Channel Restoration Project Wetland Delineation Report prepared by King County Road Services Division, Environmental Unit, dated March 10, 20 I O. The wetland delineation report described a large riverine wetland (total size approximately 140 acres) along a section of May Creek in southeastern King County near the cities of Renton and Newcastle. The project study area is located between River Mile (RM) 4.3 and 4.8 of May Creek, and included approximately 25 acres of the wetland complex (referred to as May Creek #5 in the King County Wetland Inventory (1990». The purpose of the wetland delineation was to identify the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. To determine the required buffer width, the wetland was also rated, using criteria referenced in the King County Critical Area Code (KCC 21A.318). King County adopts the Washington State's Department of Ecology: Washington State Wetland Rating System for Western Washington (Hruby 2004). May Creek #5 was determined to be a Category . II riverine wetland with a 110 foot buffer, located in the natural 100-year floodplain of May Creek. However, the portion of the study areaJwetiand that lies west of 148'h Ave SE lies within the City of Renton jurisdiction, and therefore must also be classified using those criteria. The wetland, when rated using the City of Renton classification system, is a Category 3 wetland with a 25-foot buffer. The wetland is not a Category I wetland because it does not meet any of the following criteria: a. The presence of species listed by the Federal or State government as . endangered or threatened, or the presence of essential habitat for those species; and/or b. Wetlands having forty percent (40%) to sixty percent (60%) permanent open water (in dispersed patches or otherwise) with two (2) or more vegetation classes; and/or c. Wetlands equal to or greater than ten (10) acres in size and having three (3) or more vegetatiori classes, one of which is open water; and/or d. The presence of plant associations of infrequent occurrence; or at the geographic limit of their occurrence The wetland is not a Category 2 wetland because it does not meet any of the following criteria: a. Wetlands that are not Category I or 3 wetland; and/or b. Wetlands that have heron rookeries or osprey nests, but are not Category I wetlands; and/or c. Wetlands of any size located at the headwaters of a watercourse, i.e., a wetland with a perennial or seasonal outflow channel, but with no defined influent channel, but are not Category I wetlands; and/or d. Wetlands having minimum existing evidence of human-related physical alteration such as diking, ditching or channelization 2 The wetland is a Category 3 wetland because it meets criteria in (a): a. Wetlands that are severely disturbed. Severely disturbed wetlands are wetlands which meet the following criteria: I. Are characterized by hydrologic isolation, human-related hydrologic alterations such as diking, ditching, channelization and/or outlet modification; and 2. Have soils alterations such as the presence of fill, soil removal and/or compaction of soils; and 3. May have altered vegetation Criteria (b) and (c) under the Category 3 classification·include newly emerging wetlands and all other wetlands not classified as a Category 1 or 2. These are not applicable since criteria defined in (a) are met. The hydrology within the wetland is partly controlled by May Creek, which has been channelized in the past. On the north side ofthe wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side qf the wetland, the wetland boundary more closely follows the natural valley topography. The wetland has also been degraded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. The wetland received a higher rating based on the King County and Washington State classification system, and has a larger buffer under that system (lID feet versus 25 feet with the City of Renton rating). The more conservative King County rating and buffer will be used when calculating project impacts and mitigation. 3 · . ------------------- from SE May central portion of study area (January 26 ,2010) Photo 3: Scrub-shrub portion of the wetland near Soil Pit #1 in southwestern quadrant ofthe study area (January 21 , 2010) May Creek Channel Restoration Wetland Delineation 29 Photo 2: Looking south at an undeveloped portion of the wetland just east of 148'" Avenue SE (January 21 ,2010) Photo 4 : Hydri c soil at Soil Pi t #4 i n the northwestern quadrant of the study area (January 26 , 2010) March 2010 ------------------- Photo 5: Southern extent of the wetland near Soil Pit #3 in the southeastern quadrant of the study area (January 26 . 2010) Photo 7: May Creek in the eastern portion of the study area where prolonged overbank flooding occurs (January 26.2010) May Creek Channel Restoration Wetland D elineation 30 Photo 6: May Creek in the central portion of study area where less overbank flood i ng occurs due to floodplain fill (January 21 .2010) Photo looded pasture areas withi n the wetland in the central portion of the study area (January 21 .2010) March 2010 ------------------- " ~ ;.. ,/ ~- Photo 9: Hvdric ~-.. -,'. /' ... ~l . . " ~ .. }~ "--... ~. ~ . . . . ~ ~ -- ,01;> • .'.' A i " J;;.""~ , ... ~~ .. '. .-t .. ~ .... ~ .. ..... ... ~.::. Cl v ~JO r' '~\,\f':,,~.~ .. _ •. ":;.;. J; , ...•. , ... ~ ....... '.. .... ~ ~'·T '~-,:." . . ~ ."'~ ,. \. . \ / Pit #6 in the northwestern quadrant of the study area (February 24 , 2010) Wetland area on the south side of May Creek on the west side of 148th Avenue SE (March 1, 2010) May Creek Channel Resto ration Wetland Delinea tion 31 Photo 10 : Fill area at area outside the wetland boundary (February 24, Photo 12: Wetland boundary on the south s i de of May Creek on the west side of 148th Avenue SE where the blackberry begins to grow into the reed canarygrass (March 1, 2010) March 2010 I I I I I I I I I I I I I I I I I I I Appendix B -Wetland Delineation Data Forms May Creek Channel Restoration Wetland Delineation 27 March 2010 I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanVOwner: May Creek Valley -DNRP King County ONRP Investigalor(s): Miller, Martin, Clark landform (hiUslope, terrace, etc.): Valley Subregion (LRR): Lat: Soil Map Unit Name: RdC, Bh 47.51495 City/County: King Slate: WA Sampling Date: Sampling Point Section, Township, Range: S2, T23N, RSE 1-21-2010 Soil Pit #1 local relief (concave, convex, none): flat Slope (%): 0.5 Long: -122.14239 Datum: No NWI classification: o (If no, explain in Remarks.) PEM/PSS Are climatic I hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D, Soil D. Or Hydrology D. significantly disturbed? Are Vegetation D. Soil D, Or Hydrology D, naturally problematic? Are "Normal Circumstances~ present? Yes 181 No 0 (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects Important features etc , , Hydrophytic Vegetation Present? Yes IllI No 0 Hydric Soil Present? Yes IllI No 0 Is the Sampling Area within a Wetland? Ve. IllI , No 0 Wetland Hydrology Present? Yes IllI No 0 Remarks: SP #1 south of creek just west of barbed wire fence (probably 1't property east of 148th) -about 30-35 feet south of creek. VEGETATION -Use scientific names of Dlants Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status " Prunus spp. 30 Y FACU Number of Dominant .Species That Are , 3 (A) 2, OBl, FACW, or FAC: 3, Total Number of Dominant Species Across 4 (B) 4. All Strata: 30 = Total Cov~r Percent of Dominant Species That Are 75 (NB) §5!:l2linglShIJlb Siraty!!! (Plot Size: 10m) OBl, FACW, or FAC: 5, Oemleria cerasiformis 5 N FACU Prevalence Index worksheet: 6. Salix sitchensis 30 Y FACW Tot§!1 0&1 Cover at MultiI!:l~ !;!~. 7, Salix scouleriana 30 Y FAC OBl species x1 = B, FACW species x2= 9. FAC species x3= 65 = Total Cover FACU species x4 = Herb Stratum (Plot Size: 5m) UPl species x5 = 10. Phs/arls arundlnacea 30 Y FACW Column Totals: (A) (8) 11, Unknown grass 5 N ? Prevalence Index = BIA = 12, Unknown grass Trace N ? Hydrophytic Vegetation Indicators: 13, X Dominance Test is >50% 14, Prevalence Index is :=3.0' 15, Morphological Adaptations 1 (Provide supporting data in 16, Remarks or on a separate sheet) 17, Wetland Non-Vascular Plants1 18, Problematic Hydrophytic Vegetation' (Explain) . 19, 20, 'Indicators of hydric soil and wetland hydrology must be present, 35 = Total Cover unless disturbed or problematic. WQQQ~ Vin!:!: Slwl!.:!m (Plot Size: ) 1. Rubus procerus Trace N FACU 2, 130 = Total Cover Hydrophytlc Vegetation % Bare Ground in Herb Stratum 65 Present? Yes IllI No 0 Remarks: Starting to see buds. This is a forested/scrub-shrub portion of the weiland along the stream. us Army Corps of Engineers Westem Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Valley -DNRP SOIL I Sampling Point: #1 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Typal Loc 2 Texture Remarks ---------0-18-10YR 2/1 100 Too small color 1 C M clay I I I lType: C= Concentration, D=Oepletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Localion: PL=Pore Lining, M=Matrix Hydric Soli Indicators: (Applicable to all LRRs. unless otherwise noted.) Indicators for Problematic Hydric SallS': 0 Histosol (A 1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (S1) 0 Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox DepreSSions (Fa) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (if present): Type: Depth (Inches): Hyd~lc Solis Present? Ve. 181 No 0 I Remarks: Very uniform matrix, all one horizon within 18 inches. Contains live roots. I HVDROLOGV I Wetland Hydrology Indicators: Primary indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 181 Surface Water (A 1) 0 Water·Stained leaves (B9) 0 Water·Slained leaves (B9) 181 High Waler Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1. 2. 4A. and 48) I 181 Saluration (A3) 0 Salt Crust (811) 0 Drainage Patterns (B10) 181 Water Marks (81) 0 Aquatic Invertebrates (813) 0 Dry·Season Water Table (C2) 0 Sediment Deposits (B2) 0 Hydrogen Sulfide Odor (Cl) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (B5) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (88) Field Observations: I Surface Water Present? Ves 0 No 181 Depth (inches): Water Table Present? Ves 181 No 0 Depth (inches): a inches Saturation Present? Ves 181 No 0 Depth (inches): o inches Wetland Hydrology Present? Ve. 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if avaitable: I Remarks: About 35 feet from stream in an area with less reed canarygrass. Some standing water present within about 10 feet. Assuming hydrology would also be present later in the growing season. I US Army Corps of Engineers Western Mountains, Valley, end Coast -Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanUOwner: Inv9stigator(s): May Creek Valley -DNRP King County DNRP Miller, Martin, Clark City/County: King Sampling Date: State: WA Sampling Point: Section, Township, Range: . 52, T23N. R5E 1-21-2010 Soil Pit #2 Landform (hilt~lope, terrace, etc.): Valley local relief (concave, convex, none): flat Slope (%): 0.5 Subregion (LRR): Lat: 47.51495 Soil Map Unit Name: RdC, Bh Are climatic I hydrologic conditions on the site typical for this time of year? Yes Long: -122.14239 Datum: No NWI classification: o (If no, explain in Remarks.) PEM/P$S Are Vegetation D, Soil 0, Or Hydrology D. significantly disturbed? Are -Normal Circumstances~ present? Yes ~ No 0 Are Vegetation D. Soil O. Or Hydrology D. naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations transects Important features etc , Hydrophytic Vegetation Present? Vo, 0 No IllI Hydric Soil Present? Vo, 0 No IllI Is the Sampling Area within a Wetland? Yo. 0 No IllI Wetrand Hydrology Present? Yes 0 No IllI Remarks: Too many grasses were present that we could not identify given the time of year for us to feel confident about the vegetation analysis; however, we are comfortable In saying this sample area is nol within a wetland because the hydriC soli and hydrology are not present. VEGETATION -Use scientific names of plants Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. None Number of Dominant Species That Are 1 (A) 2. OBl, FACW, or FAC: 3. Total Number of Dominant Species Across 2 (6) 4. All Strata: 0 = Tolal Cover Percent of Dominant Species That Are 50 (NS) SaplingfShr"b Stratum (Plot Size: 10m) OBl, FACW, or FAC: 5. CytJsus scoparius (scotch broom) Trace N ? Prevalence Index worksheet: B. Total ?& Cover of: Mullipl~ Ir£' 7. OBl species 0 xl = 0 8. FACW species 15 x2= 30 9. FAG species 42 x3= 126 0 = Total Cover FACU species 42 x4 = 168 Herb Stratum (Plot Size: 5m) UPl species 0 x5 = 0 10. Thistle species Trace N ? Column Totals: 99 (A) 32. (6) 11. Festuea arundlnaeea 42 Y FAC Prevalence Index = BIA = 3.2 12. Datetylis glomerata 42 Y FACU Hydrophytic Vegetation Indicators: 13. Pha/aris srundinsces 15 N FACW No Dominance Test is >50% 14. Unknown grasses No Prevalence Index;s ~3.0' 15. Morphological Adaptations 1 (Provide supporting data in 16. Remarl<s or on a separate sheet) 17. Wetland Non-Vascular Plants 1 18. Problematic Hydrophytic Vegetation1 (Explain) 19. 20. 'Indicators of hydric soil and wetland hydrology must be present, 99 = Total Cover unless disturbed or problematic. Wood~ Vine Slratum (Plot Size: 10m) 1. Rubus procerus Trace N FACU 2. 99 '" Total Cover Hydrophytlc Vegetation % Bare Ground in Herb Stratum 0% Present? Yo. 0 No IllI Remarks: us Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Valley w DNRP SOIL s I ampling Pomt: #2 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type1 Loc2 Texture Remarks --------- ().jj" 7.5YR 2.513 100 2.SYR 5/8 1 C M Sandy loam 8"18" 10YR 3/. 100 Loamy sand Contains large gravels I I I 'Type: C= Concentration, D=Oepletion, RM=Reduced Matrix. CS=Covered or Coaled Sand Grains. 2Location: PL=Pore Lining, M=Matrix Hydric Soli Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric SOilSl: 0 Histosol (A1) 0 Sandy Redox (85) 0 2 em Muck (A10) 0 Histie epipedon (A2) 0 Stripped Matrix (86) 0 Red Parent Material (TF2) I 0 Black Hislic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 0 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (S 1) 0 Depleted Dark Surface (F7) 3'ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (F8) hydrology must be present, unless disturbed or oroblematic. I Restrictive Layer (if present): Type: Depth (Inches): Hydric Salls Present? Ye. 0 No 181 I Remarks: This soil is dry as a bone and very bright. About 10 feet north of this soil pit (towards the wetland), another hole has a grayish transition (Gley1 5/1 OY) at 10-11 inches at approximate boundary between reed canarygrass and blackberry. About 5 feet north of this soil pit the color is 2.5Y 5/2 in bottom of the pit. I HYDROLOGY I Wetland Hydrology Indicators: Primary indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A1) 0 Water-Stained Leaves (89) 0 Water-Stained Leaves (B9) 0 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1. 2. 4A, and 48) I 0 Saturation (A3) 0 Sail Crust (B11) 0 Drainage Pattems (B10) 0 Water Marks (B 1) 0 Aquatic Invertebrates (813) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (B2) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorpnic Position (02) 0 Algal Mat or Crust (64) 0 Presence of Reduced Iron (C4) 0 Shallow Aquilard (03) 0 Iron Deposits (B5) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surtace Soil Cracks (86) 0 Stunted or Stresses Plants (01) (LRR Al 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (88) Field Observations: I Surface Water Present? Yes 0 No 181 Depth (inches): Water Table Present? Yes 0 No 181 Depth (inches): Saturation Present? Yes 0 No 181 Depth (inches): Wetland Hydrology Present? Ye. 0 No 181 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitOring well, aerial photos, previous inspections), if available: I Remarks: No groundwater within 18 inches of surface. I US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site; AppficanVOwner: Investigator(s): May Creek Valley -DNRP . King County DNRP Martin, Clark City/County: King Sampling Date: 1-26-2010 State: WA Sampling Point: Soil Pit #3 Section, Township, Range: 52, T23N, RSE Landform (hilislope, terrace, etc.): Valley local relief (concave, convex, none): flat Stope (%): 0.5 Subregion (LRR): Lat: 47.51495 Long: Soil Map Unit Name: RdC,Bh Are climatic I hydrologic conditions on the site typical for this time of year? Yes No -122.14239 Datum: NWI classification: o (If no, explain in Remarks.) PEM/PSS Are Vegetation ~, Soil D. Or Hydrology D. significantly disturbed? Are "Normal Circumstances" present? Yes 181 No 0 Are Vegetation D, Soil D, Or Hydrology D, naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations transects Important features etc , , , Hydrophytic Vegetation Present? Yes 181 No 0 Hydric Soif Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Yes 181 No 0 Wetland Hydrology Present? Yes 181 No 0 Remarks: Soil Pit #3 Is located on Colasurdo property, just east of the tributary along the access road. Chose this location because there are horses south of the fence. The vegetation In this area is mowed and grazed. VEGETATION -Use scientific names of plants Tree Stratum (Plot Size: 10m) 1. None 2. 3. 4. Sapling/Shrub Stratum (Plot Size: 10m ) 5. None 6. 7. B. 9. Herb Stratum (Plot Size: 5m ) 10. Juncus effusus 11. Unknown pasture grasses 12. Ranunculus repens 13. Moss species 14. 15. 16. 17. 1B. 19. 20. Woody Vine Stratum (Plot Size: ) 1. Rubus procerus 2. Absolute % Cover o o 51 42 Trace 5 98 Trace 98 Dominant Species? = Total Cover Indicator Status = Total Cover· Y Y N N = Total Cover N = Total Cover FACW ? FACW ? FACU Dominance Test Worksheet: Number of Dominant Species That Are OBl, FACW. or FAC: Total Number of Dominant Species Across All Strata: Percent of Dominant Species That Are OBl, FACW, or FAC: Prevalence Index worksheet: Total % Cover of: OBl species FACW species ? FAG species FAGU species UPl species ? 2 ? Multiply by: xl = x2 = ? x3= x4 = x5= (AI (BI (NBI Column Totals: (AI (BI Prevalence Index = BfA? Hydrophytic Vegetation Indicators: ? Dominance Test is >50% ? Prevalence Index is !:3.01 Morphological Adaptations' (Provide supporting data in Remarks or on a separate sheet) WeUand NonNascular Plants' Problematic Hydrophytic Vegetation1 (Explain) 1 Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytlc Vegetation % Bare Ground in Herb Stratum Present? Yes 181 No o Remarks: Vegetation may be marginal, but it Is difficult to determine because the area is highly disturbed with previous horse use. Some of the dominant grass types cannot be determined due to the season and mowing. Based on the large amount of juncus effusus, and the obvious Indicators of hydrology and hydric soli we are assuming that the vegetation would be hydric If given an opportunity to naturally grow. US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Vaney· ONRP SOIL Sampling Point: #3 Profile Description: (Describe to the depth needed to document the indicator or cantlon the absence of indicators.) I I Depth Matrix Redox Features (inches) Color (moist) % Coior (Moist) % Type' loc2 Texture Remarks --------- O-SS 5YR 2.5/1 100 Loamy sand Saturated to the surlace 6.5-11.5~ 10YR 5/4 90 10YR 4/6 10 C M Silty loam I 11.5-16" 10YR 4/6 100 Silty loam I I 'Type: C= Concentration, D=Depletion, RM=Reduced Matrix. CS=Covered or Coated Sand Grains. 2Localion: PL=Pore Lining, M=Matrix Hydric Soli Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Sallss: 0 Histosol (A1) 0 Sandy Redox (S5) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (AA) 0 loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (S 1) 0 Depleted Dark Surface (F7) 3'ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (FB) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric $olis Present? Ve. 181 No 0 I Remarks: At line between NB horizons, contained charcoal·like organic material. <1 cm band of mottles between AlB horizons. I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A 1) 0 Water-Stained leaves (B9) 0 Water-Stained Leaves (B9) 181 High Water Table (A2) (except MlRA 1, 2, 4A, and 4Bl (MLRA 1, 2, 4A, and 4Bl I 181 Saturalion (A3) 0 Sail Crust (B 11) 0 Drainage Pattems (B 1 0) 0 Water Marks (B1) 0 Aquatic Invertebrates (B13) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (B2) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (B3) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (B4) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (BS) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (LRR Al 0 Raised Ant Mounds (06) (LRR Al 0 Inundation Visible on Aerial Imagery (B7) 0 Other (Explain in Remarks) 0 Frost-Heave Hu~mocks (07) 0 Sparsely Vegetated Concave Surface (B8) Field Observations: I Surface Water Present? Ves 0 No 181 Depth (inches): Water Table Present? Ves 181 No 0 Depth (inches): SS Saturation Present? Ves 181 No 0 Depth (inches): surface Wetland Hydrology Present? Ve. 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: I US Anny Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I ,---------~------------------- I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: Invesligator(s): May Creek Valley ~ DNR~ King County DNRP Martin, Clark. Landform (hillslope, terrace, etc.): Valley Subregion (LRR): Lat: Soil Map Unit Name: RdC, Bh 47.51495 City/County: King Sampling Dale: 1·26·2010 State: WA Sampling Point: SoH Pit #4 Section, Township, Range: 52. T23N, R5E Local relief (concave, convex, none): flat Slope (0/0): 0.5 Long: -122.14239 Datum: No NWI classification: o (If no, explain in Remarks.) PEMIPSS Are climatic I hydrologic conditions on.the site typical for this time of year? Yes Are Vegetation D. Soil D, Or Hydrology D, significantly disturbed? Are Vegetation 0, Soil D, Or Hydrology D, naturally problematic? Are "Normal Circumstances" present? Yes 181 No 0 (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations. transects, Important features, etc. Hydrophytic Vegetation Pre'sent? Yes 181 No 0 Hydric Soil Present? Wetland Hydrology Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Yes r8I No 0 Yes 181 No 0 Remarks: Soil Pit #4 is located just southeast of SE May Valley RdJ148th Avenue SE intersection. Pit dug at the northern extent of the Spirea naar 148th. VEGETATION -Use scientific names of plants Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. Fraxinus laUrelia 60 Y FACW Number of Dominant Species That Are 3 (A) 2~ Fruit tree 5 N ? 08l, FACW, or FAC: 3. Total Number of Dominant Species Across 3 (8) 4. All Strata: 65 = Total Cover Percent of Dominant Species That Are 100% (AlB) Sa!;!BngfSb(~Q S:triiltum (Plot Size: 10 m) OBl, FACW, or FAC: 5~ Spirea douglasil 15 N FACW Prevalence Index worksheet: B. Rosa plsocarpa 20 Y FAG Tolal :y~ Qgv!i!:r Qf: Myllil:!:I:ib:i: 7. OBl species x1 = 8. FACW species x2= 9. FAC species x3= 35 = Total Cover FACU species x4 = Herb Stratum (Plot Size: 5m ) UPl species x5 = 10. Phs/arls arundinacea 100 Y FACW Column Totals: (A) (B) 11. Prevalence Index = BfA = 12. Hydrophytlc Vegetation Indicators: 13~ Ye. Dominance Test. is >50% 14. Prevalence Index is ;5.3.01 15. Morphological Adaptations 1 (Provide supporting data in 16. Remarks or on a separate sheet) 17. Wetland Non-Vascular Plants 1 18~ Problematic Hydrophytic vegetation1 (Explain) 19. 20. 11ndicators of hydric soil and wetland hydrology must be present, 100 . = Total Cover unless disturbed or problematic. W2Qd:i Vi!Jfl: S:lra!!Jll (Plot Size: ) 1. 2. 200 = Total Cover Hydrophytlc Vegetation % Bare Ground in Herb Stratum 0 Present? Ve. 181 No 0 Remarks: US Army Corps ?' Engineers Western Mountains, Valley, and Coast -Interim Version I Project Site: May Creek Valley· ONRP SOIL I Sampling Point #4 Profile Description: (Describe to the depth needed to document the Indicator or confinn the absence of indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type' Lect Texture Remarks ---------0_8.5" 10YR 2/1 100 Clay Oxidized roots a.5 -13.5" 2.5Y 2.5/1 50 10VR 5/6 50 Clay Bottom 1/3 of layer has mottles I 13.5-18 10YR 211 Clay Organic pieces, oxidized roots I I 'Type: C= Concentration, D=Oepletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix Hydric $oillndicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric 50115 3 : 0 Histosoi (A 1) 0 Sandy Redox (S5) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (S6) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I 0 Thick Oark Surface (A12) 0 Redox Dark Surface (FS) 0 Sandy Mucky Mineral (51) 0 Depleted Dark Surface (F7) 3 1ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (Fa) hydrology must be present, unless disturbed or oroblematic. I Restrictive Layer (if present): Type: Depth (Inches): Hydric Soils Present? Y •• 0 No 0 Remarks: The soil in the third layer is actually darker than the color noted, but there was not a good match in the Munsell. I I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A1) 181 Water-Stained Leaves (B9) 0 Water-Stained Leaves (89) 181 High Water Table (A2) (except MLRA 1, 2, 4A, and 4B) (MLRA 1, 2, 4A, and 4B) I 181 Saturation (A3) 0 Salt Crust (811) 0 Drainage Patterns (810) 181 Water Marks (81) 0 Aquatic Invertebrates (B13) 0 Dry-Season Water Table (G2) 0 Sediment Deposits (B2) 181 Hydrogen Sulfide Odor (G1) 0 Saturation Visible on Aerial Imagery (G9) I 0 Drift Deposits (83) 181 Oxidized Rhizospheres along living Roots (C3) 0 Geomorphic Posilion (02) 181 Algal Mat or Crust (84) 0 Presence of Reduced Iron (G4) 0 Shallow Aquitard (03) 0 Iron Deposits (85) 0 Recent Iron Reduction in nlled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (86) 0 Stunted or Stresses Plants (o1) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (87) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (88) Field Observations: I Surface Water Present? Yes 0 No 181 Depth (inches): Water Table Present? Yes 181 No 0 Depth (inches): 4S Saturation Present? Yes 181 No 0 Depth (inches): surface WeUand Hydrology Present? V •• 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: I US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: Invesligator(s): May Creek Valley -DNRP King County DNRP Miller, Clark City/County: King Stale: WA Sampling Date: Sampling Point: Section, Township, Range: 52, T23N, R5E 1-28-2010 Soil Pit #5 Landform (hiJislope, terrace, etc.): Valley Lat: Local relief (concave, convex, none): flat Slope (%): 0.5 Subregion (lRR): 47.51495 Long: -122.14239 Datum: Soil Map Unit Name: RdC, Bh PEM/PSS Are climatic f hydrologic conditions on the site typical for this time of year? Yes No NWI classification: o (If no, explain in Remarks.) Are Vegetation D, Soil D. Or Hydrology D. significanlly disturbed? Are "Normal Circumstances" present? Yes I:8l No 0 Are Vegetation D, Soil D. Or Hydrology D, naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, Important features, etc. Hydrophytic Vegetation Presenl? Yes 0 No ~ Hydric Soil Present? Yes 0 No ~ Is the Sampling Area within a Wetland? Yes 0 No ~ Wetland Hydrology Present? Yes 0 No 181 Remarks: Soli Pit #5 is located slightly east and just upslope of Soli Pit #4 (SE of May Valley Rd/14S th Ave SE Intersection). Selected spot within the change from reed canarygrass to blackberry. VEGETATION -Use sc entitle names of plan s Tree Stratum (Plot Size: 10m) 1. Acersp,* 2. Prunus sp. * 3. 4. Sapling/Shrub Stratum (Plot Size: 10m) 5. Oem/aria ceras;form;s 6. Cory/us comuta* 7. 8. 9. Herb Stratum (Plot Size: 5m) 10. Po/ystichum munltum 11. Pterldium squilinum 12. Phs/aris arundlnac8a 13. 14. 15. 16. 17. 18. 19. 20. Woody Vine Stratum (Plot Size: ) 1. Rubus procerus 2. % Bare Ground in Herb Stratum Absolute % Cover 25 15 40 20 33 53 20 20 20 60 45 198 Dominant Species? y y = Total Cover y y = Total Cover y y y. = Total Cover y = Total Cover Indicator Status FACU FACU FACU FACU FACU FACU FACW FACU Dominance Test Worksheet: Number of Dominant Species That Are OBl, FACW, or FAC: 1 (A) Total Number of Dominant Species Across All Strata: 9 (8) Percent of Dominant Species That Are OSl, FACW, or FAC: 10 (N8) Prevalence Index worksheet: Total % Coyer 01' Multig;ly by: DBl species 0 x1 = 0 FACW species 20 x2; 40 FAC species 0 x3 = 0 FACU species 178 x4 = 712 UP!:. species 0 x5= 0 Column Totals: 198 (A) 752 (8) Prevalence Index = BfA = 3.8 Hydrophytic Vegetation Indicators: No No No No No Dominance Test is >50% Prevalence Index is ~3.01 Morphological Adaptations1 (Provide supporting data in Remar\(s or on a separate sheet) Wetland Non-Vascular Plants 1 Problematic Hydrophytic Vegetation 1 (Explain) llndicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytic Vegetation Present? Yes o No Remarks: *Vegetation was hard to identify. The cherry tree appears to be ornamental-it Is next to an ornamental cedar and the maple appears to be a sugar maple and not a native maple, but It Is hard to tell this time of year. US Army Corps of Engineers Western Mountains. Valley. and Coast -Interim Version I Project Site: May Creek Valley -DNRP SOIL Sampling Point: #5 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of indicators.) I I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type' Loc2 Texture Remarks ---------0-18-7.5YR 3/3 100 5YR 5/8 5 Clay Small mottles throughout I I I 'Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coaled Sand Grains. 2Location: PL=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs. unless otherwise noted.) Indicators for Problematic Hydric Solls3: 0 Histosol (A 1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 0 Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (S1) . 0 Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (Fa) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (if present): Type: Depth (Inches): HydriC Soils Present? Ve. 0 No 181 I Remarks: I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A1) 0 Water-Stained leaves (B9) 0 Water-Stained Leaves (89) 0 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA " 2, 4A, and 48) I 0 Saturation (A3) 0 Salt Crust (B11) 0 Drainage Patterns (B10) 0 Water Marks (B1) 0 Aquatic Invertebrates (B13) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (B2) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (C9) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (B4) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (B5) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised An1 Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (B7) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (B8) I Field Observations: Surface Water Present? Vos 0 No 181 Depth (inches); Water Table Present? Ves 0 No 181 Depth (inches): Saturation Present? Ves 0 No 181 Depth (inches): Wetland Hydrology Present? Va. 0 No 181 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: No indicators of hydrology are present here. I US Army Corps C!f Engineers Western Mountains, Valley, and Coast -Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site; ApplicanUOwner: May Creek Valley. DNRP King County DNRP Investigator(s): Miller, Clark Landform (hillslope, terrace, etc.): Vaney Subregion (lRR): Lat: Soil Map Unit Name: RdC, Bh 47.51495 City/County: King Sampling Date: State: WA Sampling Point: Section, Township, Range; 52. T23N, R5E 2·24·2010 Soil Pit #6 Local relief (concave, convex, none): flat Slope (%): 0.5 Long: No -122.14239 Datum: NWI classification: o (If no. explain in Remar1<.s.) PEM/PSS Are ctimatic I hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D, Soil D,' Or Hydrology D. significantly disturbed? Are ~Normal Circumstances" present? Yes 181 No 0 Are Vegetation D, Soil D, Or Hydrology 0, naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes 181 No 0 HydriC Soil Present? Wetland Hydrology Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Yes 181 No 0 Remarks: VEGETATION -Use scientific names of plants Tree Stratum (Plot Size: 10m) 1. Thuja pI/cats 2. PS8udotsuga menziesll 3. Alnus rubra 4. Fraxinus latlfolia 5. Prunus spp. Sapling/Shrub Stratum (Plot Size: 10m) 5. Oem/eria cerasiformis 6. Rubus spectabills 7. Symphoricarpos a/bus 8. Ame/anchler a/n/folla 9. Herb Stratum (Pial Size: 5m) to. Polystichum munitum 11. moss species" 12. 13. 14. 15. 16. 17. lB. 19. 20. Woody Vine Stratum (Plot Size: 1. Rubus procerus 2. Yes 181 No 0 Absolute % Cover 20 30 35 5 5 95 5 30 5 20 60 2 60 2 10 167 Dominant Species? V Y y N N = Total Cover N y N y = Total Cover N V = Total Cover N = Total Cover Indicalor Status FAC FACU* FAC FACW FACU FACU FAC FACU FACU FACU ? FACU Dominance Test Worksheet: Number of Dominant Species That Are 3 (A) OSl, FACW, or FAC: Total Number of Dominant Species Across All Strata: 5 (8) Percent of Dominant Species That Are OSl, FACW, or FAC: 60 (AlB) Prevalence Index worksheet:. Total % Cover of' Multiply by: OBl species x1 = FACW species x2 = FAC species x3= FACU species x4 = UPl species x5= Column Totals: (A) (8) Prevalence Index = BIA = 3.4 Hydr~phytic Vegetation Indicators: Vo. Dominance Test is >50% Prevalence Index is ':='3.01 Morphological Adaptations 1 (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants 1 Problematic Hydrophylic Vegetation1 (Explain) 1 Indicators of hydric soil and wetland hydrology must be present. unless disturbed or problematic. Hydrophytlc Vegetation % Bare Ground in Herb Stratum Present? Yes 181 No 0 Remarks: *The indicator status of douglas fir Is stl11 being studied. One of the fir trees In this plot was growIng In standing water. UWe did not Include the moss In the dominance calculations. We also saw a trace of the native blackberry but did not Include that because the amount was <1%. This area passes based on the dominance test. so based on this finding hydrophytic vegetation is determined to be present. us Army Corps of Engineers West~m Mountains, Valley, and Coast -Interim Version I I I Project Site: May Creek Valley -ONRP SOIL I SamplinQ Point: #6 Profile Description: (Describe to the depth needed to document the Indicator or conflrm the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Typal Loc2 Texture Remarits ---------0-5" 10YR 2/1 100 Clay Almost to black to match the Munsell 5 -18" 10YR 2/1 100 Too small, faint 20 C M Clay Texture is even more sticky than top layer I I I 1Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix Hydric Soli Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric 501la 3 : 0 Hislosol (A1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 Histic Epipedon (A2) 0 Stripped Matrix (56) 0 Red Parent Material (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MLRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 Loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I 0 Thick Dark Surface (A 12) 0 Redox Dark Surface (F6) 0 Sandy Mucky Mineral (Sl) 0 Depleted Dark Surface (F7) llndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (F8) hydrology must be present, unless disturbed or problematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Solis Present? Ve. 181 No 0 I Remarks: Both layers are clay, but the top layer is more crumbly and contains small gravels. I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (Al) 0 Water·Stained Leaves (89) 0 Water·Stained Leaves (89) 181 High Water Table (A2) (except MLRA 1,2. 4A. and 48) (MLRA 1, 2, 4A, and 48) I 181 Saturation (A3) 0 Salt Crust (Bl1) 0 Drainage Patterns (Bl0) 0 Water Marks (81) 0 Aquatic Invertebrates (B13) 0 Dry·Season Water Table (C2) 0 Sediment Deposits (82) 0 Hydrogen Sulfide Odor (Cl) 0 Saturation Visible on Aerial Imagery (Cg) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along Living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) . 0 Iron Deposits (85) 0 Recent Iron Reduction in Tilled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (LRR A) 0 Raised Ant Mounds (06) (LRR A) 0 Inundation Visible on Aerial Imagery (97) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave Surface (B8) I Field Observations: Surface Water Present? Yes 0 No 181 Depth (inches): Water Table Present? Yes 181 No 0 Depth (inches): 9" Saturation Present? Yes 181 No 0 Depth (inches): surface Wetland Hydrology Present? Ye. 181 No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: I us Anny Corps of Engineers Western Mountains, Valley, and Coast -Interim Varsion I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApphcanUOwner: May Creek Valley -DNRP King County DNRP Investigator(s): Miller, Martin, Clark Landform (hiltslope, terrace, elc.): Valley Subregion (LRR): Lal: SoH Map Unit Name: RdC, Bh 47.51495 City/County: King State: WA Sampling Date: Sampling Point: Section, Township. Range: 52, T23N, R5E 2-24-2010 Soil Pit #7 local relief (concave, convex, none): flat Slope (%): 0.5 long: -122.14239 Datum: No NWI classification: o (If no, explain in Remarks.) PEM/PSS Are climatic I hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D. Soil D, Or Hydrology D. significantly disturbed? Are "Normal Circumstances· present? Yes 181 No 0 Are Vegetation D. Soil D, Or Hydrology D. naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations transects important features etc , . Hydrophytic Vegetation Present? Yes 181 No 0 Hydric Soil Present? Yes 181 No 0 Is the Sampling Area within a Wetland? Ye. 181 .No 0 Wetland Hydrology Present? Yes 181 No 0 Remarks: This pit is located on the southwest side of May Creek near fence posts. The hole was pre-exlsting -it appears it may be leftover from when the fence was installed. VEGETATION -Use scientific names of plants Tree Stratum (Plot Size: 10m) 1. None 2. 3. 4. Sapling/Shrub Stratum (Plot Size: 10m) 5. Spirea doug/asll 6. 7. B. 9. Herb Stratum (Plot Size: 5m ) 10. Pha/aris arundlnacea 11. 12. 13. 14. 15. 16. 17. 1B. 19. 20. Woody Vine Stratum (Plot Size: 10m) 1. None 2. Absolute % Cover o 25 25 75 75 100 Dominant Species? = Total Cove~ .y = Total Cover Y = Total Cover = Total Cover Indicator Status FACW FACW Dominance Test Worksheet: Number of Dominant Species That Are DBl, FACW, or FAC: Tolal Number of Dominant Species Across All Strata: Percent of Dominant Species That Are OBl, FACW, or FAC: Prevalence Index worksheet: Total % Cover of: DBl species FACW species FAC species FACU species UPl species 2 2 100 Multiply by' x1 = x2= x3 = x4 = x5 = (A) (8) (AlB) Column Totals: (A) (8) Prevalence Index = B/A = Hydrophytic Vegetation Indicators: Ye. Dominance Test is >50% Prevalence Index is '::3.0' Morphological Adaptations 1 (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants' Problematic Hydrophytic Vegetation' (Explain) 'Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytlc Vegetation % Bare Ground in Herb Stratum 0 Present? Yes 181 No 0 Remarks: Some riparian plantings at edge of plot were recently installed, and are too small to provide any coverage. We excluded those plantings from this plot US Army Corps of Engineers Western Mounteins, Valley, end Coast -Interim Version I Project Site: May Creek Valley· DNRP SOIL Sampling Point: #7 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Typal Loc2 Texture Remarks ---------0-2~ Duff layer Mostly reed canarygrass roots 2 _18w 10 YR 3/2 80 SYR 5/8 20% C PL, M clay I I I 1Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains, 2Location: PL=Pore Lining, M=Matnx Hydric Soli Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problemat : Hydric 501la 3 : 0 Histascl (A 1) 0 Sandy Redox (55) 0 2 em Muck (A10) 0 Histic Epipedon (,1\2) 0 Stripped Matrix (56) 0 Red Parent Malerial (TF2) I 0 Black Histic (A3) 0 Loamy Mucky Mineral (F1) (except MlRA 1) 0 Other (Explain in Remarks) 0 Hydrogen Sulfide (A4) 0 loamy Gleyed Matrix (F2) 0 Depleted Below Dark Surface (A 11) IlSI Depleted Matrix (F3) I 0 Thick Dark Surface (A12) 0 Redox Dark Surtace (F6) 0 Sandy Mucky Mineral (S1) 0 Depleted Dark Surface (F7) J'ndicators of hydrophytic vegetation and wetland 0 Sandy Gleyed Matrix (54) 0 Redox Depressions (F8) hydrology must be present, unless disturbed or problematic. I Restrictive layer (if present): Type: Depth (Inches): Hydric Soils Present? Ye. IlSI No 0 I Remarks: I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 0 Surface Water (A 1) 0 Water-Stained leaves (89) 0 Water-Stained leaves (89) IlSI High Water Table (A2) (except MlRA 1, 2, 4A, and 48) IMLRA 1, 2, 4A, and 48) I IlSI Saturation (A3) 0 Salt Crust (B 11) 0 Drainage Patterns (B10) 0 Water Marks (81) 0 Aquatic Invertebrates (813) 0 Dry-Season Water Table (C2) 0 Sediment Deposits (B2) 0 Hydrogen Sulfide Odor (C1) 0 Saturation Visible on Aerial Imagery (Cg) I 0 Drift Deposits (83) 0 Oxidized Rhizospheres along living Roots (C3) 0 Geomorphic Position (02) 0 Algal Mat or Crust (84) 0 Presence of Reduced Iron (C4) 0 Shallow Aquitard (03) 0 Iron Deposits (BS) 0 Recent Iron Reduction in nlled Soils (C6) 0 FAC-Neutral Test (05) I 0 Surface Soil Cracks (B6) 0 Stunted or Stresses Plants (01) (lRR Al 0 Raised Ant Mounds (06) (lRR A) 0 Inundation Visible on Aerial Imagery (B7) 0 Other (Explain in Remarks) 0 Frost-Heave Hummocks (07) 0 Sparsely Vegetated Concave SUlface (B8) Field Observations: I Surface Water Present? Yes 0 No IlSI Depth (inches): Water Table Present? Yes IlSI No 0 Depth (inches): 12" Saturation Present? Yes IlSI No 0 Depth (inches): surface Wetland Hydrology Present? Yes IlSI No 0 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: I US Anny Corps of Engineers Western Mountains, Valley, and C08st -Interim Version I I I I I I I I I I I I I I I I I I I I Appendix C -Wetland Photos May Creek Channel Restoration Wetland Delineation 28 March 2010 II ·4· c • en "Tl iii" ::r o I I 0 I ~ I ~ I _ il." 03 I - s: Q) '< (") CD CD ;:;'1\ < Q) --CD '< ~ ~ -Q) ::J 0.. ~ o o to » CD ..., _.