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HomeMy WebLinkAboutMiscSW 34t Street Culvert Replacement Project —Fish and Wildlife Habitat Report R.W. Beck Associates ■ December 2005 oEVELDPME Q tpr[T�a lNG f tTY OF MAR % v 29'3fi MCEIVED Biological Assessment SW 34th Street Calvert Replacement Project Fish and Wildlife Habitat Report Prepared for: R.W. Beck Associates 1001 4th Avenue, Suite 2500 Seattle, WA 98154-1004 Contact: Michael Giseburt, P.E. Prepared by: �•SS �i Jones & Stokes 11820 Northup Way, Suite E300 Bellevue, WA 98005 Contact: Andy Wones 425/822-1077 December 2005 This document should be cited as: Jones & Stokes. 2005. Biological Assessment. SW 34th Street Culvert Replacement Project —Fish and Wildlife Habitat Report. December. (AS 05287.05) Bellevue, WA. ti Table of Contents Chapter 1. Introduction.......................................................1-1 Chapter 2. Project Description ........................................... 2-1 2.1. Project Area........................................................................ 2-1 2.2. Action Area.........................................................................2-1 2.3. Project Purpose..................................................................2-1 2.4. Design Criteria....................................................................2-3 2.5. Culvert Design....................................................................2-4 2.6. Hydraulics........................................................................... 2-5 2.7. Construction Sequence.......................................................2-7 2.8. Staging Areas................................................................... 2-10 2.9. Construction Access ............................ ............................. 2-10 2.10. Construction Equipment....................................................2-10 2.11. Construction Methods ........................ ............................... 2-11 2.12. Erosion, Sediment, and Pollution Control ..........................2-11 2.13. Conservation Measures and BMPs...................................2-12 Chapter 3. Existing Environmental Conditions ................3-1 3.1. Environmental Baseline......................................................3-1 3.1.1. Salmonid Habitat Conditions....................................3-1 3.2. Species Occurrence in the Project Action Area .... .............. 3-6 3.2.1. Bull Trout .......... ........................................................ 3-6 3.2.2. Puget Sound Chinook Salmon ................................. 3-7 3.2.3. Bald Eagle................................................................3-9 3.2.4. Other ESA -listed Species.......................................3-10 Chapter 4. Analysis of Effects ............................................ 4-1 4.1. Salmonids...........................................................................4-1 4.1.1. Direct Effects ............................................... ............. 4-1 4.1.2. Indirect Effects ...................... ................................... 4-2 4.1.3. Effects of Interdependent or Interrelated Actions ..... 4-2 4.2. Bald Eagles... ...................................................................... 4-2 4.2.1. Direct Effects............................................................4-2 4.2.2. Indirect Effects ............ ............................................. 4-3 4.2.3. Effects of Interdependent or Interrelated Actions ..... 4-3 December 2005 r SW 3411 Street Culvert Replacement Project Biological Assessment Chapter 5. Determinations of Effect...................................5-1 5.1. Chinook Salmon................................................................. 5.1 5.2. Bull Trout............................................................................ 5-1 5.3. Bald Eagle.......................................................................... 5-2 Chapter 6. Evaluation of Essential Fish Habitat ...............6-1 Chapter 7. References.........................................................7-1 it R.W. Beck Associates (05287.05) 3 Contents List of Tables Table 1-1. Project Contacts..................................................................................................1-2 Table 2-1. Excavation and Fill Volumes (cubic yards) ..........................................................2-5 Table 2-2. Hydraulic Performance of Culvert Replacement Alternatives under Future 100-Year Conveyance Event............................................................................... 2-6 Table 2-3. Predicted Maximum Velocities at SW 34th Street Culvert for 2-Year Event ......... 2-7 Table 3-1. Checklist for Documenting Environmental Baseline and Effects of the Proposed Action on Relevant Salmonid Habitat Indicators.................................................... 3-2 List of Figures Figure 2-1. Regional Vicinity Map of Project Area..................................................................2-2 Appendices Appendix A. Project Drawings Appendix B. Fish Exclusion Guidelines Appendix C. Photographs of the Project Area Appendix D. NOAA Fisheries and USFWS Species Listing Information i December 2005 t SW 34th Street Culvert Replacement Project Biological Assessment Acronyms BA biological assessment BMPS best management practices BRPS Slack River Pumping Station cfs cubic feet per second CMP corrugated metal pipe Corps U.S. Army Corps of Engineers DPS distinct population segment EFH essential fish habitat ESA Endangered Species Act ESCL erosion and spill control lead ESGRWP East Side Green River Watershed Plan ESU evolutionarily significant unit FEQ model full equations model fps feet per second HPA hydraulic project approval LSOG late successional old growth LWD large woody debris mgll milligrams per liter NHP Natural Heritage Program NOAA Fisheries National Marine Fisheries Service NRCS Natural Resources Conservation Service NTU nephelometric turbidity units NWFP Northwest Forest Plan PFMC Pacific Fisheries Management Council PHS priority habitats and species Project SW 34�1 Street Culvert Replacement Project RM river mile SPCC spill prevention, control, and containment USFWS U.S. Fish and Wildlife Service USGS U.S. Geological Survey WDFW Washington Department of Fish and Wildlife WDNR Washington State Department of Natural Resources WRIA water resources inventory area R.W. Beck Associates (05287.05) - ••- - • •_._._ Chapter 1 . Introduction This biological assessment (BA) was completed to facilitate interagency consultation required under Section 7 of the federal Endangered Species Act (ESA) for the City of Renton (City) SW 341h Street Culvert Replacement Project (Project). The Project will include temporary impacts to Springbrook Creek and associated wetland areas and will require coverage under a U.S. Army Corps of Engineers (Corps) 404 Permit. The Project is scheduled for construction during the summer of 2007. The City proposes to replace the SW 34'h Street culvert across Springbrook Creek to improve streamflow capacity at this crossing and reduce flooding in the Renton Valley. Replacement of this culvert was identified in the City's East Side Green River Watershed Plan (ESGRWP) as a drainage need for the City (R.W. Beck 1997). The existing crossing consists of four side -by -side 72-inch-diameter corrugated metal pipe (CMP) culverts. These culverts have insufficient capacity for high flows and cause water to back up behind the culvert and even to overtop the road during peak flows. In addition to overtopping SW 34`' Street, the conveyance restriction at SW 34"i Street contributes to upstream flooding at SW 43r' Street and Lind Avenue. Several projects identified in the ESGRWP have been completed, including the SW 271h Street Culvert Replacement Project in 1999. The SW 34`h Street culvert replacement is the next highest priority project in the valley area. Improving conveyance at this crossing will correct overtopping of SW 34`h Street and lower upstream water levels so that other future planned projects will provide flood protection in areas upstream in the Renton Valley. The existing SW 34`h Street culverts would be replaced by a single 30-foot-wide and 10-foot-tall four-sided concrete box culvert. Although the existing crossing is not currently a barrier to fish passage, future conditions are predicted to increase peak discharge velocity to up to 5 feet per second (fps) (R.W. Beck 2005). Replacement of the SW 34`h Street culvert will reduce velocity at this crossing, reduce flooding December 2005 SW 34'6 Street Culvert Replacement Project Biological Assessment upstream, and provide an improved fish habitat condition in the culvert vicinity. The new crossing will have natural substrates, improve conveyance of high flows and associated debris, and reduce contact of stream water with roadway surfaces that may contribute vehicle -related pollution to the stream. Key contacts involved in the design and permitting of this Project are listed in Table 1-1. Table 1.1. Project Contacts AgencylFirm Role Contact Phonelemail Address City of Renton Lead Agency, Allen Quynn, 425 430-7247 City of Renton, Public SEPA Review, P.E., Project aquynn@ci.renton.wa.us Works Department, Shorelines Manager 1055 S. Grady Way, Renton, WA 98055 R.W. Beck Consultant Michael 206 695-4607 1001 Fourth Ave, Suite Team, Project GiseburL mgiseburt@rwbeck.com 2500, Manager P.E. SeatUe, WA 98154- 1004 R.W. Beck Consultant Lisa Gorry, 206 6954757 1001 Fourth Ave, Suite Team, Project P.E. [gorry@nwbeek.com 2500, Engineer Seattle, WA 98154- 1004 Jones & Stokes Consultant Andy Wones 425 893-6447 11820 Northup Way, Team, Permit awonesQjsanet.com E300, Bellevue, WA Application 98005 U.S. Army Corps Susan (206) 764-5527 Seattle District Corps of Corps of Project Powell Susan_M.Powell@ Engineers Regulatory Engineers Manager, 404 NWS02_usace.army.mil Branch, CENWS-OD- Permit RG Attn: Susan Powell, P.O. Box 3755 Seattle, WA 98124-3755 Washington Area Habitat Larry Fisher 425 649.7042 clo Dept. of Ecology Department of Biologist, fishldf@dfw.wa.gov 319016VI Ave SE Fish and Wildlife Hydraulic Bellevue, WA 98D08 (WDFW) Project Approval (HPA) R.W. Beck Associates (05287.05) �'2 Chapter 2. Project Description 2.1. Project Area The Project is located in the Renton Valley at the crossing of SW 34'h Street and Springbrook Creek_ The Project area is at the boundary between Township 23 N, Range 5 East, Section 30 and Township 23 N, Range 4 East, Section 25. See Figure 2-1 for a map of the Project vicinity. 2.2. Action Area The Action Area for noise effects of the Project includes a 0.5-mile radius of the Project area, due to the potential for loud noise during construction activities. Instream effects would include an Action Area 100 feet upstream and 300 feet downstream of the SW 34'h Strcet/Springbrook Creek crossing_ The Project disturbance area and a buffer area of 100 feet in each direction of the disturbance footprint is the Action Area for listed plant species. However, this area was closely examined during the wetland delineation, and no suitable habitat or individuals of the two listed plant species occurring in King County (golden paintbrush [Castilleja levisecia] and marsh sandwort [Arenaria paludicola]) were found. 2.3. Project Purpose The primary objective of the Project is to increase conveyance capacity through the SW 34'h Street crossing at Springbrook Creek to eliminate roadway overtopping and reduce upstream water levels during flood events. Through the development of the S4V a ' 1 SILNet C :I%Ie!L R�?piareme,Tt Project 61r,loa'�al AssessnipnT Figure 2-1. Regional Vicinity Map of Project Area ESGRWP, a target criterion that allows no more than 0.1 foot of head loss (water elevation rise) through culverts for the future I00-year flow was used. This criterion was originally developed with input from the Natural Resources Conservation Service (NRCS, formerly Soil Conservation Service). Other Project goals include cost-effective construction, meeting environmental permit requirements, coordination of Project construction with any future roadway improvements, and improving fish passage. P,AV. Beck As nr::r. r; ^ Project Qeaeription 2.4. Design Criteria General criteria and issues considered when reviewing alternatives were: • Traffic capacity —The replacement culvert must also be designed to handle HS25 traffic loading. ■ Cost —A lower cost alternative is preferred. in A method of construction that allows quick progress is preferred in order to comply with WDFW approved in -water construction windows (June 15 through September 30). ■ The work area at the Project site is limited. A type of construction that does not require a large lay -down area is preferred. ■ It is preferred to limit the amount of ground dewatering required. ■ Traffic Impacts —The City desires the option of having phased construction to keep at least one lane of traffic open. • It is preferred to limit the impact of construction on local businesses. ■ Utilities Relocation —Several utilities cross above the existing culverts. Raising the top of the new culvert above the top of the existing culverts would require relocation of the existing utilities. The option of not relocating these utilities is not possible because the construction of the replacement culvert below the location of these utilities would lirnit the height of the culvert and would not provide enough hydraulic cross section through the culvert to meet the Project criteria. ■ Temporary Stream Diversion —Diversion of creek flow will be required during construction. It is estimated that a minimuin diversion flow of 140 cubic feet per second (efs) with 1 foot of freeboard will be required (R.W. Beck 2005). Groundwater Control --Control of groundwater will be required during construction for constructability and to assure an adequate foundation. Wells and/or sumps will be required to draw the local water table below the earthwork elevation. • Fish Passage —Alternatives that provide the largest open area, lowest streamflow velocities, natural bottom conditions, and open water surface are generally preferred. When a four-sided box culvert is used, the bottom of the box is set 20%, or about 2 feet, below the grade of the stream and infilled with appropriate substrate material (clean, well-rounded cobble and gravel). ■ Foundation Type and Settlement —A closed -bottom four-sided box culvert provides a more forgiving structure regarding possible settlement issues as compared with the three -sided box with separate footings because of the wide, continuous footing created by the bottom. 2.3 December 2005 SW 34'� Street Culvert Replacement Prc act Biological Assessment Based on the combination of these criteria, a single four-sided box culvert, 30 feet wide by 10 feet high, was selected for this Project. 2.5. Culvert Design The Project would install a single 30-foot-wide by 10-foot-high by 80-foot-long box culvert. Project drawings of this alternative are shown in Figures A-3 and A-4 of Appendix A. A single culvert can be utilized because the extra height allows a free water surface through the culvert during the 100-year design flow and meets the head -loss criteria. The actual culvert height from footing to top of culvert would be 11.5 feet to provide below -grade depth to the footing. Footings will be precast, continuous full -width spread footings approximately 18 inches thick. The box culvert would require the road grade to be raised approximately 23 feet above the existing road. To minimize the amount the existing road is required to be raised, the road pavement could be placed directly on the culvert's precast top. Tapering the raised road back into the existing roadway with vertical curves would require reconstruction of approximately 300 feet of SW 34`h Street. Reconstruction would include adjustment of driveways, manhole covers, curbs and gutters, sidewalks, and landscaping. New low points along SW 34th Street would be created and would require the installation of new stormwater catch basins. An existing 8-inch-diameter sanitary sewer line would be relocated and routed approximately 900 feet cast to 1_.ind Avenue_ A water supply line would be routed along the downstream face of the culvert in a carrier pipe. This water line would be housed inside of a protective 22-inch-diameter pipe. Gas, electric, and communications lines would be routed under the culvert. During construction a temporary pipeline would be required for Springbrook Creek diversion. Earth embankment cofferdams with impervious lining would be installed, and two 48-inch-diameter pipes would be installed to route flow around the construction excavation (see Figure A-5 in Appendix A). This approach was successfully employed on the SW 271h Street Culvert Replacement Project in 1999. Culvert installation will require temporary disturbance of approximately 5,331 square feet (0.12 acre) of wetland and associated stream area. In addition, 6,387 square feet (0.15 acre) of wetland and stream buffer would be temporarily disturbed. No permanent loss of wetland or stream habitat would occur. Excavation and fill volumes are shown in Table 2-1. B.W. Beck Associates 105287,05) if 1 Project Description Table 2-1. Excavation and Fill Volumes (cubic yards) Location Total Excavation Excavation Below OHWM Total Fill Fill Below OHWM Entire Site 5848 99 32681 0 Wetland 1 Buffera 275 NA 0 NA Wetland to 81 19 0 0 Wetland 2 Buffer 192 NA 0 NA 1 Wetand 21 80 80 0 0 Notes: OHWM = ordinary high-water mark Wetland buffer defined as 50 feet to either side of delineated wetland boundary. Wetland 1 includes stream and adjacent wetland area upstream (south) of SW 341h Street Wetland 2 includes stream and adjacent wetland area upstream {north) of SW 34m Street a "Fill quantity includes 277 cy of spawning gravels. 2.6. Hydraulics Hydraulic analysis was performed using the Full Equations (FEQ) model that was developed during the ESGRWP and since updated in the ESGRWP Technical Update Supplement —Draft (R.W. Beck 2004). The analysis simulations reflect the future land use condition, 100-year conveyance condition flow, and future conveyance system as recommended in the ESGRWP. The future conveyance system was used as opposed to the existing conveyance system to ensure that when all valley improvements are fully implemented these improvements will work together to meet the flood protection goals and target water surface elevations identified in the ESGRWP. The key future improvements include both downstream and upstream improvements including: • Removal of the private bridge north of SW 27th Street, ■ SW 391h Street to SW 43ra Street pipe system improvements, ■ Renton wetland mitigation project, and ■ Oakesdale (SW 41" Street) culvert replacement. As part of the ESGRWP, two types of potential flood events were analyzed: a storage scenario, which includes events that produce very high water surface elevation at the Black River Pumping Station (BRPS) due to pumping restrictions, and a conveyance scenario, which includes events that exhibit maximum peak flows into the pump station forebay (severe local flood event). At the SW 34"' Street culvert, the water surface elevations for the 100-year storage scenario are actually higher than the conveyance scenario. However, the conveyance event is the critical event for 2.5 December 2005 SW 341h Street Culvert Replacement Project Biological Assessment consideration of the culvert replacement because of significantly higher flows. For this reason the comparison focused just on the 100-year conveyance event. Table 2.2. Hydraulic Performance of Culvert Replacement Alternatives under Future 100-Year Conveyance Event New SW 341" Street Crossing (Z) Downstream Upstream Change in Water Water Surface Water Surface Elevation Elevation Surface (head loss) (ft) AlternativeM Elevation Existing Conveyance —Future Flow 17,30 19.1 1.7 One 30- by 10-ft Box Culvert 17.07 17.13 0.06 Source: R.W. Beck 2005. Note the clear open area is specified. The actual height would be increased by approximately 1.5 to 2 feel to allow a natural substrate for fish passage. 2 Elevation Datum: NAVD 88. In addition to considering the 100-year future condition for flood control, additional analysis was conducted to assess stream velocities through the culvert to meet fish passage requirements. This was done by determining the stream velocity through the culvert for the 2-year event. Typically, WDFW requires consideration of the 10% exceedance flow (i.e., the flow that is exceeded 10% of the time) for current land use conditions. Since the 10% exceedance flow is typically 35-45% of the 2-year flow, using the 2-year flow for the analysis provides a conservative estimate of high velocity. Table 2-3 compares the predicted velocities for the existing and proposed culverts under existing and future land use conditions. Installation of the proposed culvert would reduce peak velocities, which could be significant for fish passage, especially under future land use conditions. The proposed design would meet WDFW passage criteria for adult trout and salmon under all flow conditions, whereas the existing culvert would exceed the velocity criteria for passage of adult trout under expected future conditions. R.W. Beck Associates (05287.051 Z s Project Descriptio❑ Table 2-3. Predicted Maximum Velocities at SW 34th Street Culvert for 2- Year Event Existing Land Use Conditions Future Land Use Conditions Peak Water Peak Peak Water Peak Flow-3 Surface Velocity Flow3 Surface Velocity Alternative (cfs) Elevation2 (fps) (cfs) Elevation (fps) Existing Culvert 318 13.9 2.8 561 15.7 5.0 (four 72-inch culverts) Alternative 2 318 13.7 1.9 561 14.9 2.7 One 30- by 10•ft Box Culvert' Source: R.W. Beck 2005. Note the clear open area is spedfied. The actual height would be increased by approximately 1.5 to 2 feet to allow a natural bottom for fish passage. z Elevation Datum: NAVD 88. 3 Source: FEQ modeling results from East Side Green River Watershed Plan Supplement, R.W. Beck 2004. Draft. 2.7. Construction Sequence The anticipated construction sequence is listed below. The actual sequence will be determined by the construction contractor. The sequence below assumes that one lane will remain open through the duration of construction. However, it is possible that the entire road will be closed. If the road is closed, the north and south (westbound and eastbound) portions of the Project would be constructed together rather than separately, as described below - I. Hold preconstruction conference with City. 2. Mark construction limits. 3. Install erosion control best management practices (BMPs), including silt fencing and storm drain filter inserts. 4. Construct sewer extension to route existing sewer service east to connect to existing sewer main near Lind Avenue and abandon existing sewer over the culvert. 5. Install temporary block netting upstream and downstream of the work area. 6. Remove fish from the isolated culvert area according to fish exclusion guidelines (Appendix 13). 7. Install temporary bypass culverts (two 48- inch -diameter CMP culverts). 2-7 1 December 2005 SW 3411 Street Culvert Replacement Project Biological Assessment S. Install temporary earthen cofferdams with impervious linings upstream and downstream of the construction area to divert flow to the bypass culverts and isolate the construction area. 9. Place traffic control to move traffic to north half of road. 10. Install sheet piles near roadway centerline to allow excavation of south half of road. 11. Install dewatering system measures. 12. Remove existing pavement, sidewalks, and roadway fill from castbound lane of the crossing (south half of crossing). Dewater as excavation proceeds. 13. Coordinate excavation with removal/relocation and, if required, temporary service for underground utilities (gas, water, electric, communications). 14. Excavate and remove existing 72-inch culverts from south half of crossing. 15. Excavate sediment to below existing road grade in south half of crossing as well as excavation for wing wall. 16_ Haul excavated soils off -site or stockpile reusable soils, if allowed based on final design, at least 150 feet from Springbrook Creek. 17. Install relocated underground utilities that are to be placed under the south half of the new culvert crossing. 18. Install and compact crushed rock or controlled density fill below culvert foundation elevation to provide suitable foundation. 19. Install precast culvert bottom. Note the bottom section will include a knee -wall (short vertical walls integral to the precast culvert bottom section) in south half of crossing. 20. Construct south wing walls. 21. Place streambed material in bottom of the culvert and in and around new wing walls. 22. Install culvert top in south half of crossing and grout in place. 23. Backfill around culvert and compact. R,V1i', Beck Associates (05287.05} 2,8 Project tDesuiption 24. Construct curb and gutter, sidewalk, and initial roadway pavement improvements on south half crossing. Improvements include transitions to existing road as a result of raising the road higher than existing conditions. 25. Revise traffic control to south side of road, including pedestrian traffic. 26. Revise placement of sheet piling to allow connection between first phase of culvert and second phase. 27. Remove existing pavement, sidewalks, and roadway fill from westbound lane of the crossing (north half of crossing). Dewater as excavation proceeds. 28. Coordinate excavation with removal/relocation and, if required, temporary service for underground utilities (gas, water, electric, communications) 29. Excavate and remove existing 72-inch culverts from north half of crossing 30. Excavate sediment to below existing road grade in north half of crossing as well as excavation for wing wall. 31. Haul excavated soils off -site or stockpile reusable soils, if allowed based on final design, at least 150 feet from Springbrook Creek 32. Install relocated underground utilities that are to be placed under the north half of the new culvert crossing. 33. Install and compact crushed rock or controlled density fill below culvert foundation elevation to provide suitable foundation. 34. Install precast culvert bottom. 35. Construct north wing walls. Extend existing drainage piping to connect to creek through wing walls. 36. Place streambed material in bottom of the culvert and in and around new wing walls. 37. Install culvert top in north half of crossing and grout in place. 38. Backfill around culvert and compact. 39. Construct curb and gutter, sidewalk, and initial roadway improvements on north half crossing. Improvements include transitions to existing road as a result of raising the road higher than existing conditions. 2-9 December 2005 SW 34N Street Cuivert Replacement Project Biological Assessment 40. Install fish habitat improvements (two pairs of root wads) upstream and downstream of culvert 41. Perform final lift of asphalt roadway improvements. 42. Remove cofferdams and temporary pipe diversion, allowing creek to flow through new culvert. 43. Hydroseed and plant disturbed areas. 44. Remove storm drain filter inserts. 45. Remove silt fence and other temporary erosion and sediment control (TESL) BMPs when seeded areas have stabilized. 2.8. Staging Areas Project construction will require closing at least one lane of SW 341h Street to traffic. Therefore, the roadway will be used for Project staging. Excavated soil may be temporarily stockpiled on the roadway or at an upland site away from the construction area during culvert installation. All soil stockpiles and vehicle fueling and equipment staging areas will be located at least 154 feet from surface waters. 2.9. Construction Access Construction access will be by SW 34`h Street. No off -road travel will be required. 2.10. Construction Equipment Construction equipment will include the following: ■ Excavator ■ Dump truck ■ Flatbed truck • Mobile crane ■ Drilling rig ■ Dewatering pumps ■ Generator ■ Vibratory compactor ■ Paver R.W, Seek Associates (05287.05) 2-1D Pm3ect Descr3piion 2.11. Construction Methods The construction area will be clearly marked, and all ground disturbance and equipment use will occur within the marked construction boundaries. Erosion and sedimentation BMPs will be used to control erosion and the potential for silt and turbidity to reach Springbrook Creek. These BM Ps will include (but are not limited to) installation of silt fences and temporary storm sewer filter inserts. All instream work will be completed within the approved (Fisher 2006) construction window (June 15 through September 30). Prior to beginning any instream work, National Marine Fisheries Service (NOAA Fisheries) fish exclusion protocols will be implemented to remove and exclude fish from the work area. Following fish removal and exclusion, cofferdams will be installed to isolate the construction area. The Project will divert Springbrook Creek around the existing and future culvert location. The diversion will be through two 48-inch-diameter CMPs installed for this purpose. The new culvert would be installed in two phases in order to maintain one lane open to traffic during construction. One lane would be closed off, the existing culvert excavated from that side of the road, and the new culvert installed under that half of the roadway, then paved over. In the next phase, the other half of the stream would be closed off and the process would be repeated to complete the other half of the Project. The culvert and wing walls would be made of precast concrete sections. These sections would be lifted into place by means of a mobile crane. A bacichoe would be used to place imported bed substrate material and backfill material around the new culvert. Some temporary storage of bed and backfill material may occur on the closed portion of SW 341h Street. Backfill material would be compacted by rolling or using a vibratory compactor. 2.12. Erosion, Sediment, and Pollution Control Cofferdams installed to isolate the Project from Springbrook Creek will prevent sediment that was disturbed during culvert installation from affecting Springbrook Creek. Silt fences will be used if there are areas on the sides of the construction area that drain beyond the cofferdams_ Because some soil stockpiling may occur on the SW 341h Street roadway, storm drain sediment filters will be used to prevent contamination of road runoff with turbidity and suspended sediment. - L_31 T 2-1 ?e+:ember 2005 SW 341 Street Culvert Replacement ❑rojwct Blot4cal Assessment 2.13. Conservation Measures and BMPs To the greatest extent possible, impacts to fish, wildlife, and habitat will be avoided. The following conservation measures will be used to avoid or minimize the potential for impacts to fish, wildlife, water quality, and habitat. 1. Timing. In -water construction will be conducted only during the approved (Fisher 2006) in -water work window (June 15 through September 30). No in - water work will be conducted between October 1 and June 14. The Project is scheduled to be constructed during 2007. 2. The City will comply with WDFW guidelines for fish passage, HPA conditions, Corps guidelines for culvert replacement, and the terms and conditions of the Corps permit. 3. Clearing limits will be clearly marked prior to construction. Fish removal and site isolation will occur prior to diverting water around the Project and will follow NOAA guidelines (Appendix B). 5. In consideration of the existing site conditions and the level of noise activity required for construction, no specific conservation measures are needed or proposed for the protection of bald eagles. 6. Water withdrawn to dewater the Project site will be re -injected into the ground downstream of the Project to ensure no interruption of flow in Springbrook Creek downstream of the Project during construction. 7. All soil stockpiles and vehicle fueling and equipment staging areas will be located at least 150 feet from surface waters. 8. The construction contractor will designate one individual as the erosion and spill control lead (ESCL). The ESCL will be responsible for installing, monitoring, and maintaining erosion and sediment control BMPs and maintaining spill containment and control equipment_ The ESCL will be responsible for construction compliance with local, state, and federal erosion and sediment control requirements. 9. All silt fencing and staking will be removed upon Project completion. 10. Protective covering will be placed over exposed soil areas. No disturbed ground shall remain exposed for more than 7 days between May 1 and September 30 and no more than 3 days between October I and April 30 if construction activities are not occurring in that area. Protective covering will be clear plastic sheeting, straw mulch, jute matting, or erosion control blanket per Washington State Department of Ecology requirements. R.W. Beck Associates (05287,05) ii2 Project Description 11. Exposed soils will be seeded and covered with straw mulch after construction is complete. Any temporary construction impact areas will be revegetated with native plants. 12_ A Spill Prevention, Control, and Containment (SPCC) Plan will be prepared, and all equipment will be properly maintained to successfully implement the plan. All equipment will be inspected and maintained, and absorbent material will be kept on -site. Personnel will be knowledgeable and trained in the implementation of the SPCC Plan and in associated equipment and materials necessary to correctly implement the SPCC Plan. Emergency contact information will be available on -site, in the event that a spill of hazardous materials does occur during construction. Measures that will be included in the SPCC Plan include: a. The contractor will be required to prepare and adhere to a SPCC plan. The SPCC Plan will consist of the following elements for the prevention, control, and containment of an accidental spill of hazardous materials. i. All hazardous materials will be stored on land in containers clearly labeled with the contents and appropriate for the specific material. Containers shall be stored in areas with appropriate safeguards (under cover, on an impervious surface). ii. No fueling or maintenance of construction equipment will occur within 150 feet of surface waters. iii. Personnel who transfer or otherwise handle hazardous materials will be trained in the safe handling of the materials and have knowledge of the SPCC Plan and procedures and equipment necessary to initiate control and containment of a spill. iv. Inspections of equipment and hazardous materials storage areas will occur on a daily basis. v. If an accidental spill were to occur, personnel on -site will immediately initiate measures to control the source of the spill and contain the spilled material. vi. Materials necessary for the control and containment of a spill of hazardous materials will include, but may not be limited to, oil -absorbent booms, oil -absorbent rags, and other appropriate absorbent materials. vii. All materials necessary for the control and containment of hazardous materials will be kept within the Project corridor, and personnel will be knowledgeable of their Iocations and their manner of use. viii.If an accidental spill of hazardous materials were to occur, the appropriate agencies will be notified. ix. Control and containment efforts will take precedence over all other Project -related work. Work will not resume until a spill has been 2.13 December 2005 SW 341- Street Culvert Replacement Project Biological Assessment contained and cleaned up and the cause of the spill identified and measures taken to rectify the problem. x. Materials used in control and containment efforts will be collected and disposed of at an approved facility designed for the safe handling of hazardous materials. R.W. Beck Associates (05287.1)5( 2-14 Chapter 3. Existing Environmental Conditions The existing environmental conditions were determined through the review of published data sources, databases, and direct observations in the field. Information on the currently listed species was obtained from NOAA Fisheries and the U.S. Fish and Wildlife Service (USFWS) web sites on November 29, 2005 (Appendix D). Information on site use by ESA -listed and WDFW-managed species was obtained by review of WDFW priority habitats and species (PHS) database and Washington State Department of Natural Resources (WDNR) Natural Heritage Program (NHP) data. Other sources included the Water Resource Inventory Areas (WRIA) 9 salmon and steelhead habitat limiting factors analysis (Kerwin and Nelson 2000) and other sources cited in this document. Direct observations of habitat characteristics were made during a site visit on April 5, 2005, by Jones & Stokes biologists. 3.1. Environmental Baseline 3.1.1. Salmonid Habitat Conditions The discussion below addresses the existing conditions within the Action Area of the Project. For salmonids the discussion is focused on those elements of the environment identified by the USFWS in the document titled A Framework to Assist in Making Endangered Species Act Determinations ofEffect for Individual or Grouped Actions at the Bull Trout Subpopulation Watershed Scale (U.S. Fish and Wildlife Service 1998) and Making Endangered Species Act Determinations of Effect for Individual or Grouped Actions at the Watershed Scale prepared by NOAA Fisheries (National Marine Fisheries Service 1996). These matrices were developed by the USFWS and NOAA Fisheries to analyze the effects of activities on federal forestlands in the Pacific Northwest and are rated relative pre -development optimal 3.1 December 2005 SW 34 1 Street Culvert Replacement Project BVogica! Assessment habitat conditions. This matrix was developed to analyze the effects of activities at the watershed scale and in a wide range of environmental conditions. Please refer to Table 3-1 for an overview of the environmental baseline conditions for each system. Table 3-1. Checklist for Documenting Environmental Baseline and Effects of the Proposed Action on Relevant Salmonid Habitat indicators Effects of Project Actions on Baseline Environmental Conditions Environmental Conditions Diagnostic/Pathway Properly Not Properly Indicators Functioning At Risk Functioning Improved Maintained Degraded Water Quality Temperature X X Sediment X X (local short-term impact) Chemical X X Contamination/Nutrients Habitat Access Physical Barriers X X Habitat Elements Substrate Embeddedness X X Large Woody Debris X X (LWD) Pool Frequency X X Pool Quality X X Off -channel Habitat X X Refugia X X Channel Conditions and Dynamics Width/Depth Ratio X X Streambank Condition X X Floodpiain Connectivity X X Flow/Hydrology Change in Peak/Base X X Flows Drainage Network X X Increase Watershed Conditions R.W. Beck Associates (05267,051 3-2 Existing Environmental Conditions Effects of Project Actions on Baseline Environmental Conditions Environmental Conditions Diagnostic/Pathway Properly Not Properly Indicators Functioning At Risk Functioning Improved Maintained Degraded Road Density and X X Location Disturbance History X X Riparian Reserves X X Subpopulation Characteristics Specific to Bull Trout Subpopulation size NIA X Growth and Survival N/A X Life History Diversity and NIA X Isolation Persistence and Genetic N/A X Integrity Environmental Baseline Sources? Kerwin and Nelson 2000; Washington State Department of Ecology 2005. Checklist and criteria for functional ratings from National Marine Fisheries Service 19% and U.S. Fish and Wildlife Service 1996, Water Quality Temperature Water temperatures in Springbrook Creek basin in excess of 18°C have been recorded (Harza 1995; Kerwin and Nelson 2000). The Springbrook Creek system has two excursions of temperature criteria on the 1998 303(d) list but has been removed from the 303(d) list in the latest (2002--2004) version (Washington State Department of Ecology 2005). This indicator is considered to be not properly functioning. Sediment and Turbidity Turbidity levels within the Springbrook Creek subbasin have exceeded water quality criteria for Class A waters. Mean absolute turbidity values ranged from 16 to 42 nephelometric turbidity units (NTU) at five sites in lower Springbrook and Mill creeks, while maximum values at these sites ranged from 104 to 197 NTU (Harza 1995). Streambank conditions along Mill Creek, a tributary of Springbrook Creek, show evidence of severe downcutting. Streambank erosion likely contributes to elevated sedimentation and turbidity in Springbrook Creek. Other sources of turbidity could include road and parking lot runoff from this urbanized watershed. This indicator is considered to be not properly functioning. 3.3 December 2005 SW 34�h Street Culvert Replacement Project Biolgical Assessment Chemical and Nutrient Contamination The Springbrook (Mill) Creek system is on the 2002-2004 303(d) list for excursions of water quality parameters, including dissolved oxygen and fecal coliform (Washington State Department of Ecology 2005). In addition, temperature, pH, Bis(2-ethylhexyl)phthalate, and copper have shown occasional excursions, resulting in a Category 2 listing, Springbrook Creek was formerly (1998) 303(d) listed for several other toxic metals, but recent testing has shown Springbrook Creek to meet standards for these substances. Although water quality appears to have improved, dissolved oxygen and bacteria continue to exceed standards. Therefore this indicator is not properly functioning. Habitat Access Physical Barriers The BRPS, located downstream near the confluence of Springbrook Creek and the Green/Duwamish River, is a partial barrier to fish migration. Adult salmonids are able to pass upstream of the BRPS, while juveniles cannot negotiate upstream past the BRPS. Once above the BRPS, adult salmonids cannot migrate back out of the system downstream of the BRPS, while juveniles are able to migrate out. On occasion, adult chinook salmon have strayed into Springbrook Creek, where there is little suitable spawning habitat, and have been unable to return to the Green River (Kerwin and Nelson 2000). Dense reed canarygrass (Phalaris arundinacea) may also impair passage where it spans shallow portions of the channel (Kerwin and Nelson 2000). Water quality in Springbrook Creek and lower Mill Creek (tributary to Springbrook Creek) may pose a barrier to fish migration under certain conditions. Harza (1995) noted that chinook salmon entered the BRPS between September 17 and October 22 of 1994. During this time water temperature reached 20.2°C at the BRPS. At the same time, dissolved oxygen at the Mill Creek U.S. Geological Survey (USGS) gage averaged 4.5 milligrams per liter (mg/1), ranging from 0.9 mg/I to 10.1 mg/l. Similarly, percent saturation of dissolved oxygen ranged from 9.2% to 86.1%, averaging 42.5%. These levels indicate that conditions in lower Mill and Springbrook creeks were often lethal to salmonids during this time period (Harza 1995). These conditions likely pose a significant obstacle to migrating salmonids. This indicator is considered not properly functioning. Habitat Elements Substrate Embeddedness Springbrook Creek sediments are dominated by fines in the Project vicinity. The low gradient of this stream contributes to low stream velocity, and fine sediment is not as readily transported as it would be in a higher gradient stream. Harza (1995) indicated R.W. Beek Associates (05287.05) ¢ Existing Environmentai Conditions that severe downcutting was occurring in Mill and Garrison creeks and low to moderate downcutting was occurring in Springbrook Creek. Erosion from these sites and urban runoff upstream may contribute fine sediment to Springbrook Creek. This indicator is not properly functioning. Large Woody Debris Within the Action Area, LWD is absent. LWD is also absent from much of Springbrook Creek. Woody riparian vegetation is lacking at the Action Area, and recruitment of wood into the stream is limited to certain areas. Due to the low gradient and velocity of this stream, wood is not readily transported downstream. This indicator is not properly functioning. Pool Frequency The Springbrook Creek channel has been modified in many areas, including the Action Area, where the channel is a straight trapezoidal channel with little internal complexity and almost no sinuosity. As a result the channel has a relatively consistent depth. The channel does include deepwater habitat, however, and low velocity due to the low gradient of this stream. Mill Creek, a major tributary of Springbrook Creek, also has a modified channel with little pool development. This indicator is not properly functioning. Channel Conditions and Dynamics WidthlDepth Ratio Although some portions of Mill Creek (upstream of Springbrook Creek) are downcut, altering the naturally occurring width/depth ratio (Jones & Stokes 2004), the width/depth ratio generally is less than 10 as it is in the Project vicinity. Therefore the width/depth ratio is properly functioning. Streambank Condition Streambanks in the Project vicinity are heavily vegetated with reed canarygrass. While this invasive species is detrimental to habitat condition, it appears adequate to maintain channel stability in the low -energy environment of Springbrook Creek. Streambank conditions within the Mill Creek subbasin are significantly degraded. The level of development within the subbasin, relocations and channelization of streams, and removal of riparian vegetation have caused severe downeutting of the streambanks within the subbasin (Harza 1995). While the specific percentage of stable versus unstable streambanks is unknown, this indicator is likely functioning at risk. 3.5 December 2105 SW 34�� Street Culvert Replacement Project Biological Assessment Floodplain Connectivity The Springbrook Creek subbasin has been isolated from the Green/Duwamish River floodplain by the BRPS and dikes and levees along both the Green/Duwamish River and streams in the Springbrook Creek subbasin. The streams in the Springbrook Creek subbasin, including Mill Creek, have been significantly modified as evidenced by their lack of meandering and uniform trapezoidal morphology. This indicator is considered to be not properly functioning. Flow/Hydrology Change in Peak/Base Flow The level of development within the Springbrook Creek subbasin is significant and has caused an increased flashiness to streamflow, with higher peak flows and reduced base flow as the amount of impervious surface area within the subbasin has increased. This indicator is considered to be not properly functioning. Increase in Drainage Network Due to Roads The drainage network in the Springbrook Creek subbasin is significant due to the level of development. This indicator is considered to be not properly functioning based on the level of development. Watershed Conditions Road Density and Location The road density within the Springbrook Creek subbasin is significantly greater than 3 miles per square mile and includes valley -bottom roads in close proximity to stream channels. Therefore this indicator is not properly functioning. Disturbance History The Springbrook Creek subbasin is an urbanized setting and does not meet the Northwest Forest Plan (NWFP) standard for Late Successional Old Growth (LSOG) retention that is a criterion for determining the rating of this indicator. The Project is not located in a forested setting, and the equivalent clearcut area is much greater than 15% of the subbasin. This indicator is considered to be not properly functioning. 3.2. Species Occurrence in the Project Action Area 3.2.1. Bull Trout Bull trout of the CoastaUPuget Sound Distinct Population Segment (DPS) were listed by the USFWS as threatened under the ESA on November 1, 1999 (64 FR 58910). All naturally spawning populations of bull trout in the continental United States are R.W. Beck Associates (05287.05) �� Existing Environmental Conditions included in the listing. On January 9, 2001 (66 FR 1628), Washington stocks of Dolly Varden (Salvelinus malma) were also listed as threatened because they are similar in appearance to bull trout. Stocks in the Project Vicinity A sustainable population of bull trout is not known to occur within the Green/Duwamish River basin (Washington Department of Fish and Wildlife 1998); therefore, the indicators specific to bull trout subpopulation characteristics are not applicable. Although no bull trout have been documented in the Springbrook Creek subbasin, they have been recorded occasionally in the Green/Duwamish River (Goetz 2004) and could, therefore, enter Springbrook Creek, Habitat Requirements and Ecology Bull trout of the Coastal/Puget Sound DPS exhibit four life history strategies: resident (nonmigratory), fluvial (migrating within a river), adfluvial (migrating between rivers and lakes in a watershed), and anadromous (migrating between freshwater and marine environments). Bull trout prefer cold water and structurally complex habitats. The Coastal/Puget Sound population is the only bull trout DPS in which anadromous individuals occur_ Bull trout spawn in the fall, and fry typically emerge in late February or early March. Cold, clear water and clean gravel are required for successful reproduction and rearing. Fry prefer habitat with abundant cover, and juveniles seek out cool water when water temperatures begin to exceed 59°F. Rearing occurs for several years before fish move into larger water bodies to mature. Designated Critical Habitat Critical Habitat for the Coastal/Puget Sound DPS was designated on September 26, 2005, and includes the mainstem of the Green River downstream of Springbrook Creek (70 FR 185:56212-56311). Compliance with Recovery or Management Plan Springbrook Creek is not within the Core Management Areas defined in the Draft Bull Trout Recovery Plan (U.S. Fish and Wildlife Service 2004). As such, the recovery criteria and specific goals of the plan do not apply to Springbrook Creek. 3.2.2, Puget Sound Chinook Salmon The Puget Sound Evolutionarily Significant Unit (ESU) of chinook salmon was designated as threatened on March 24, 1999 (64 FR 14308), and reaffirmed on June 28, 2005 (70 FR 37160). This ESU includes all naturally spawned spring, summer, and fall runs of Chinook salmon in the Puget Sound region from the North Fork Nooksack River to the Elwha River on the Olympic Peninsula, inclusive (Myers 3 7 December 2005 SW 349, Street Culvert Replacement Project BVogEcaI Assessment et at. 1998). Trends for the ESU are predominantly positive for the South Sound, as compared to the North Sound and Hood Canal, both of which have a predominantly negative trend. Stocks in the Project Vicinity The Green River chinook salmon run has remained relatively stable, while other Puget Sound stocks have declined (Kerwin and Nelson 2000). It is estimated that the average run size during 1968-1997 (those that spawn and those captured) was approximately 41,000. Approximately 5,700 fish per year are estimated to spawn naturally. However, natural reproduction may be masked by strays from the large hatchery returns in this watershed (Kerwin and Nelson 2000). Small numbers of adult chinook salmon have been known to enter the Springbrook Creek system and attempt spawning in the vicinity of the SW 27`h Street culvert located about 0.5 mile downstream from the Project. It is not known if any of these fish have spawned or reared successfully (Kerwin and Nelson 2000) in the poor quality habitat of Springbrook Creek. Habitat Requirements and Ecology Adult summer/fall chinook salmon migrate into their natal streams to spawn in September and October. Chinook salmon require clean, cool water and clean gravel for spawning. Eggs are deposited and buried in gravel nests where they incubate. Eggs reside in the gravel until hatching in 90 to 150 days, depending on water temperature. Chinook salmon from the Green River typically leave freshwater within the first year of life. After hatching, fry rear in their natal streams for up to 5 months. Rearing occurs from February through June. The best rearing habitat is generally associated with pools and wetland areas where woody debris and overhanging vegetation can provide cover and protection. The young fish begin their migration to salt water March through July, with peak migration occurring in June. The salmon then mature in marine waters until between 2 and 6 years old, when they return to their home system to spawn. The average age of chinook spawners is 4 years (Myers et al. 1998). Designated Critical Habitat Critical Habitat for Puget Sound chinook salmon was designated on September 2, 2005, and will become effective January 2, 2006 (70 FR 52630). This habitat includes the Black River and Springbrook Creek. Compliance with Recovery or Management Plan Chinook salmon recovery planning is being managed in conjunction with a coalition of salmon management interests called the Shared Strategy for Puget Sound. These interests include NOAA Fisheries, USFWS, the governor's office, Puget Sound treaty R.W. Beck Associates (05287.05) �� Existing Environmental Conditions tribes, state natural resources agencies, local governments, and key non -governmental organizations. A draft plan has been completed (Shared Strategy for Puget Sound 2005). The draft plan is guidance rather than a regulatory document. This Project is consistent with the Shared Strategy for Puget Sound draft plan (Shared Strategy for Puget Sound 2005) and complementary, with a conceptual project proposed in that plan (Project LG-19). Project LG-19 would rehabilitate habitat for rearing and off -channel refuge on Springbrook Creek at river mile (RM) 1.0 (downstream of SW 34`h Street). No part of the SW 34Ih Street culvert replacement would prevent implementation or effectiveness of Project LG-19_ In fact, the root wads that will be installed upstream and downstream of the culvert are precisely the type of improvement called for in the Shared Strategy for Puget Sound draft plan (Shared Strategy for Puget Sound 2005). Therefore the SW 34`h Street culvert replacement is consistent with salmonid recovery planning. 3.2.3. Bald Eagle The bald eagle is listed as threatened by the USF W S; however, the bald eagle has been proposed for removal from the federal list of endangered and threatened wildlife (64 FR 36454-36464). The species breeds across much of Canada, the Pacific Northwest, throughout the Great Lake states, and along the eastern and Gulf coasts. Bald eagles are recovering as a breeding species in other areas of interior North America. Washington hosts one of the largest populations of wintering bald eagles in the lower 48 states as well as one of the largest populations of nesting pairs. The majority of nesting bald eagles in Washington occur west of the Cascade Mountains (Smith et al. 1997). Early declines in bald eagle populations were attributed to human persecution and destruction of riparian, wetland, and conifer forest habitats. However, the widespread use of organoehlorine pesticides that caused eggshell thinning and subsequent reproductive failure was the most important factor in the decline of the species (Detrich 1985). Various legal and management measures, including restrictions placed on the use of organochlorine pesticides in 1972, development and implementation of the Pacific Bald Eagle Recovery Plan (U.S. Fish and Wildlife Service 1986), and local bald eagle management plans, have contributed to the continuing recovery of bald eagle populations. Target numbers of nesting pairs in the region have been met (64 FR 36453-36464). Stocks in the Project Vicinity Bald eagles may occasionally visit the site, although there are no records of eagles at this location. The closest known bald eagle nest is approximately 2 miles away and is located along the Green River (Washington Department of Fish and Wildlife 3-g December 2005 SW 3411 Street Culvert Replacement Project Biological Assessment 2005). There are no bald eagle nests in the Project vicinity or within line of sight of the Project. Occasionally, bald eagles may forage on waterfowl in the Project vicinity; however, there are no records of this activity. Sycamore trees located several hundred feet upstream of the SW 34'h Street culvert could potentially be used by perching bald eagles. However, during winter months, eagles are more likely to forage along the Green River due to the presence of sizable salmon runs and more numerous suitable perch trees. Habitat Requirements and Ecology Bald eagles typically nest in stands of old -growth trees near large water bodies. Nests are often constructed in the largest tree in a stand with an open view of the surrounding environment. Nest trees are usually near water and have large horizontal limbs. Snags and dead topped live trees may be important in providing perch and roost sites within territories. Because of their large size, eagles require ready access to an abundant supply of medium to large fish during breeding (Johnsgard 1990). Freedom from human disturbance is probably another important component of suitable nesting habitat (Rodrick and Milner 1991). Bald eagles winter along rivers, lakes, and reservoirs that support adequate fish or waterfowl prey and have mature trees or large snags available for perch sites. Bald eagles often roost communally during the winter, typically in a stand of mature trees with an open branching structure and well -developed canopies. Winter roost areas are usually isolated from human disturbance (Johnsgard 1990). Although Springbrook Creek does attract waterfowl, and a run of coho salmon, there are no mature trees or snags in the Project vicinity suitable for bald eagles to perch and no sand bars, a favored foraging habitat. Designated Critical Habitat The USFWS has not designated or proposed Critical Habitat for the bald eagle (U.S. Fish and Wildlife Service 1986). Compliance with Recovery or Management Plan The proposed action will not violate the recommended protection measures for bald eagles as outlined in the Pacific States Bald Eagle Recovery Plan (U.S. Fish and Wildlife Service 1986). 3.2.4. Other ESA -listed Species There are no recorded sightings or suitable habitat for the other ESA -listed species that may occur in King County (Appendix D) in the Project Action Area. These R.W. Beck Associates (05281.05) 3�10 Existing Environmental Conditions species (as identified by the USFWS) include Canada lynx (Lynx canadensis), gray wolf (Canis lupus), grizzly bear (Ursus arctos), marbled murrelete (Brachyramphus marmoratus), northern spotted owl (Strix occidentalis caurina), marsh sandwort (Arenaria paludicola), and golden paintbrush (Castilleja levisecta). None of these animal species are normally found in urban environments such as the Action Area. The ESA -listed plant species are have not been observed in King County is recent years and require conditions (acidic bog habitat for marsh sandwort and open grassland for golden paintbrush) not found in the Action Area (Washington State Department of Natural Resources 2005). Neither of these species was found in the Action Area during wetland delineation and site reconnaissance surveys. 3-11 December 2005 Chapter4. Analysis of Effects 4.1. Salmonids Salmonids present in Springbrook Creek at the time of construction may be subjected to direct effects related to isolation and dewatering of the work area. Following completion of the Project, other (indirect) effects are expected. The long-term effect of the Project will likely be beneficial to salmonids in Springbrook Creek. This would affect primarily coho salmon, which arc managed under the Magnuson - Stevens Act (see Essential Fish Habitat evaluation in Chapter 6), but would affect chinook salmon if and when they are present in Springbrook Creek. 4.1.1. Direct Effects The potential direct effects to fish and fish habitat from the Project include the following. ■ The temporary diversion of streamllow may temporarily increase sediment transport and deposition to areas downstream of the Project site. ■ Excavation and grading may increase the likelihood of sediment transport and deposition to areas downstream of the Project site. ■ Dewatering and excavation of the Project site may increase sediment transport and deposition to areas downstream of the Project site. ■ An accidental spill of hazardous materials could occur; however, such an occurrence is highly unlikely. ■ Relocation of fish from the construction area will require handling (seining, electrofishing, and dip netting), which may stress the fish involved. However, approved fish removal methods (Appendix B) will be used to minimize the at December 2005 SW 34z' street Culvert Replacement Project Biological Assessment potential for fish injury. Because this work will be completed during the approved in -water work window (July 1 through August 31), it is anticipated that only eoho salmon and cutthroat trout will be present. Conservation measures, including isolation of the in -channel work area, adherence to timing restrictions, use of a Baker Tank for treating dewatering discharge as necessary, and erosion and sediment control measures, are anticipated to minimize the potential for these impacts. 4.1.2. Indirect Effects Indirect effects include effects that may occur during operation of the facility subsequent to Project completion. Indirect effects may also occur should primary prey species be affected. Operation of the culvert will improve fish passage by reducing stream velocity during high -flow events. Operation of the culvert would also have the beneficial impact of reducing roadway overtopping events upstream, which would reduce pollutant exposure to stream water and the potential for fish stranding. Root wads and associated alcoves that will be installed upstream and downstream of the new culvert will add habitat complexity and provide refuge during high -flow events, benefiting salmonids. No adverse indirect effects from the proposed Project have been identified. 4.1.3. Effects of Interdependent or Interrelated Actions No interdependent and/or interrelated actions have been identified. 4.2. Bald Eagles 4.2.1. Direct Effects Direct effects include those that may occur during Project construction. Potential direct effects associated with the proposed action would be disturbance of foraging or perching bald eagles as a result of Project -related noise and activity. Because the Project area does not contain suitable bald eagle nesting habitat, disturbance would not occur to nesting bald eagles. There are no large snags or other perch sites in the Project vicinity. The largest trees in the Project vicinity are a row of several approximately 12-inch-diameter sycamore trees south of the Project on the east bank. These trees have few branches large enough for bald eagle perch sites. There are no sand bars in the Project vicinity. The only trees that will be removed in construction of the Project are a few willows (less than 6-inch diameter). Because of the urban/industrial environment of the Project environs, it is likely that any bald eagles that may occur in the Action Area would be acclimated to noise and R.W. Beck Associates (05237.05) 4-2 Analysis of Effects would not be negatively affected by the construction noise and activity associated with the proposed Project. In consideration of the limited habitat value oCthe Project site, the small area of impact, and the temporary nature of the construction, the Project is not considered to have a direct effect on bald eagles. 4.2.2. Indirect Effects Indirect effects include effects that may occur during operation of the facility subsequent to Project completion. Indirect effects may also occur should primary prey species be affected. No potential indirect effects from the proposed Project have been identified. 4.2.3. Effects of interdependent or Interrelated Actions The proposed action has not been linked to any other actions that could affect protected species, nor is it expected to cause or contribute to any such actions. Thus, no interdependent and/or interrelated effects have been identified. 4.3 December 2005 Chapter 5. Determinations of Effect 5.1. Chinook Salmon Because Chinook salmon in the Green River watershed typically migrate out to salt water before the in -water work window when in -channel construction would occur, and because the in -channel construction would be isolated from the stream with temporary cofferdams, the Project is expected to have no direct effect on Chinook salmon. The Project would improve habitat conditions slightly in Springbrook Creek by reducing impoundment of floodwater behind the culvert, reducing the frequency and extent of flooding upstream, and through the installation of rootwads and alcove habitat with shading vegetation upstream and downstream of the Project. Therefore, the Project would have a beneficial effect on habitat, which has been designated as Critical Habitat for Puget Sound Chinook salmon. Therefore the Project may affect but is not likely to adversely affect Chinook salmon or designated critical habitat. If Chinook recolonize the Springbrook Creek basin at some date in the future, the Project will have a beneficial effect for this species. 5.2. Bull Trout Bull trout are not known or expected to inhabit Springbrook Creek. This low -gradient, tow -elevation highly modified channel does not have habitat suitable for bull trout. In addition, all in -channel work would be conducted within the isolation of cofferdams upstream and downstream of the Project. Springbrook Creek is not designated as Critical Habitat for bull trout. Therefore, the Project will have no effect on Coastal\Puget Sound bull trout. December 2005 SW 3411 Street Culvert Replacement Praject Biological Assessment 5.3. Bald Eagle There are no bald eagle nests or roost trees in the Project vicinity, and no trees greater than 5 inches in diameter would be removed for the Project. Although bald eagles may occasionally fly over the site and could on occasionally forage for waterfowl near the site, they would be more likely to be concentrated along the Green River located approximately 0.75 mile west of the Project. Considering the lack of perching habitat, the existing urban/industrial condition of the area, and the temporary nature of the construction, the Project is considered to have no effect on bald eagles. R.W. Beck Associates (05287.05) 5-2 Chapter 6. Evaluation of Essential Fish Habitat Public Law 104-297, the Sustainable Fisheries Act of 1996, amended the Magnuson - Stevens Fishery Conservation and Management Act to establish new requirements for Essential Fish Habitat (EFH) descriptions in federal fishery management plans and require federal agencies to consult with NOAA Fisheries on activities that may adversely affect EFH. The Pacific Fisheries Management Council (PFMC) has designated EFH for the Pacific salmon fishery, federally managed groundfish, and coastal pelagic fisheries (Pacific Fishery Management Council 1999). The Magnuson -Stevens Act requires consultation for all federal agency actions that may adversely affect EFH_ EFH consultation with NOAA Fisheries is required by federal agencies undertaking, permitting, or fiinding activities that may adversely affect EFH, regardless of their location. Under Section 305(b)(4) of the Magnuson - Stevens Act, NOAA Fisheries is required to provide EFH conservation and enhancement recommendations to federal and state agencies for actions that adversely affect EFH. Wherever possible, NOAA Fisheries uses existing interagency coordination processes to fulfill EFH consultations with federal agencies. For the proposed action, this goal is being met by incorporating EFH consultation to ESA Section 7 consultation, as represented by this BA. The EFH designation for the Pacific salmon fishery 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 impassible barriers identified by PFMC (1999). Activities occurring above impassable barriers that are likely to adversely affect EFH below impassable barriers are subject to the consultation provisions of the Magnuson -Stevens Act. In estuarine and marine areas, proposed designated EFH for salmon extends from the nearshore and tidal submerged environments within state territorial waters out to the full extent of the exclusive 6�7 December 20GS SW 3411 Street Culvert Replacement Project Biological Assessment economic zone offshore of Washington, Oregon, and California north of Point Conception (Pacific Fishery Management Council 1999). The Pacific salmon management unit includes chinook, coho, and pink salmon. EFH for chinook salmon and coho salmon does occur within the Project Action Area. EFH for groundfish and coastal pelagic species does not occur within the Project Action Area. The Project could potentially result in temporary effects to water quality during culvert removal and installation (as described in Chapter 4). However, replacement of the culvert will help reduce roadway flooding upstream and therefore will reduce contact of stream water with roadway pollutants. The Project will include habitat improvements with the installation of root wads and associated plantings and will reduce peak -flow velocity at the SW 34'h Street crossing. No permanent adverse effects to EFH for Pacific salmon will occur. Therefore, the Project will have no adverse effect on EFH for Pacific salmon and will benefit coho salmon by improving habitat quality accessibility of habitat upstream of the culvert. R.W. Beck Associates (05287.05) i Chapter 7. References Detrich, P.J. 1985. The Status and Distribution of Bald Eagle in California. M.S. thesis. Chico, CA: California State University, Chico. Goetz, F. A., E. Jeanes, and E. Beamer. 2004. Bull Trout in the Nearshore. Preliminary Draft. U.S. Army Corps of Engineers. Seattle District. Seattle, WA. June. Harza. 1995. Final Report: Comprehensive Fisheries Assessment of the Mill Creek, Garrison Creek and Springbrook System_ Consultant report prepared for the City of Kent, Environmental Engineering. Kent, WA. Johnsgard, P.A. 1990. Hawks, Eagles, and Falcons of North America. Washington, DC: Smithsonian Institution Press. Kerwin, John, and Nelson, Tom S. (eds.). 2000, Habitat Limiting Factors and Reconnaissance Assessment Report, Green/Duwamish and Central Puget Sound Watersheds (WRIA 9 and Vashon Island). December. Washington Conservation Commission and the King County Department of Natural Resources. Myers, J.M., R.G. Kope, G.J. Bryant, D. 'feel, L.J. Lierheimer, T.C. Wainwright, W.S. Grand, F.W. Waknitz, K. Neely, S.T. Lindley, and R.S. Waples. 1998. Status Review of Chinook Salmon from Washington, Idaho, Oregon, and California. (NOAA Tech. Merino, NMFS-NWFSC-35.) U.S. Department of Commerce. National Marine Fisheries Service (NOAA Fisheries). 1996. Making Endangered Species Act Determinations of Effect for Individual or Grouped Actions at the Watershed Scale. Environmental and Technical Services Division, Habitat Conservation Branch. December 2005 SW 34 ^ Street Colvert Repfacement Project Biological Assessment Pacific Fishery Management Council (PFMC). 1999. Amendment 14 to the Pacific Coast Salmon Plan, Appendix A: Identification and description of Essential Fish Habitat, adverse impacts, and recommended conservation measures for salmon. Available: <http://www.pcouncil.org>. Accessed: February 26, 2001. Portland, OR. R.W. Beck, Inc. 1997. East Side Green River Watershed Plan. Prepared for the City of Renton. R.W. Beck, Inc. 2004. Draft FEQ Modeling Results fur the East Side Green River Watershed Plan. Prepared for the City of Renton. R.W. Beck, Inc. 2005. SW 34'`` Street Culvert Replacement Project. Final Pre - Design Report. Prepared for the City of Renton. November. Rodrick, E., and R. Milner (tech. eds.). 1991. Management Recommendations far Washington Priority Habitats and Species. Olympia, WA: Washington Department of Wildlife. Shared Strategy for Puget Sound (SSPS). 2005. Draft Puget Sound Salmon Recovery Plan. Seattle, WA. June 30. Available: <http://www.sharedsalmonstrategy.org>. Accessed: December 8, 2005. Smith, M.R., P.W. Mattocks, Jr., and K.M. Cassidy. 1997. Breeding Birds of Washington State. Volume 4 in K.M. Cassidy, C.E. Grue, M.R. Smith, and K.M. Dvomich (eds.), Washington State Gap Analysis —Final Report (Publications in Zoology No. 1). Seattle, WA: Seattle Audubon Society. Streamnet. 2005. Streamnet salmon distribution online database. Available: <http://www.streanmet.org>. Accessed: December 8, 2005, U.S. Fish and Wildlife Service (USFWS). 1986. Recovery Plan for the Pacific Bald Eagle. Portland, OR. U.S. Fish and Wildlife Service (USFWS). 1998. A Framework to Assist in Making Endangered Species Act Determinations of Effect for Individual or Grouped Actions at the Bull Trout Subpopulation Watershed Scale. U.S. Fish and Wildlife Service (USFWS). 2004. Draft Recovery Plan for the Coastal/Puget Sound Distinct Population Segment of Bull Trout (Salvelinus confluentus). Puget Sound Management Unit (including the Chilliwack River and associated tributaries flowing into British Columbia, Canada). Portland OR. May. Washington Department of Fish and Wildlife (WDFW). 1998. Washington State Salmon and Steelhead Stock Inventory: Bull Trout and Dolly Varden Appendix. Olympia, WA. R.W. Back Associates (05287.45) 7 2 References Washington State Department of Ecology (Ecology). 2005. Washington State's Water Quality Assessment t303(d) & 305(b) Report]. Final 2004 Submittal. Available: <http://www.ecy.wa.gov/programs/wq/303d/2002/ 2 002 -index. html>. Accessed: December 5, 2005. Washington State Department of Fish and Wildlife (WDFW). 2005. Priority Habitats and Species database. Renton Quad. Washington State Department of Natural Resources (WDNR). 2005. Natural Heritage Program. Available: <http:/rbwvw.dnr,wa.gov/nhp/>. Accessed: December 12, 2005. 7-3 December 2005 Appendix A Project Drawings I v) CL CDIKRI I - CONCRE-E f -50' WETLAND BUFFFR I'01ND 2' WOM CAP * CONCRETE DOWN D.4 N 1 CASE A" TIE CENTER OF NTENSUCIIDN MTH SW Mi STKFT W OAx5DALE AVE SW, SMRIEY CONTROL DATA 14,5E PDRA ID(619fi. PUBLISHED ELEYAIKN1 19,504 U.S. SURVEY FEET. vN I I RN/2 SSW RN 19.22 E E 13.54 IF 19 13 Q cHANNND.ED W.I .AT FRONT OF WALA At Kw, CO CORNER 12.0625E iRX.EwAY N .062E M'35 E 1,295,35E fi602 BALK ELEVATION 18.82 FEET I �. � ASixil, � Sc ELC GATE EL 11167 BUILT EL Ixa9 --- 61➢G CD 119E I MM 19,50 [ M 17.55 A 1166 BOT ISA2 ASPHAT 50' WETLAND BUFFER I_ Ecc I n I - - sOMx WET, A�4C eprtE XOL� "I C7 RN 19.45 - EW 11.82 �1� V, IIfZ) II E IIA3 - M l--R 51 WCE Z a WE I Be 11.25 DO FEET DN 04/19/2005 n + z ;+ V r WETLAND 2 411 v - 08 _ sP a -e F_?D 7/" CMI' STOK',7 'E 8 G° '7 CAAr 10RM Clli' -R �� � P-n _: 1 05 r,.r WA R SU?N'AL ON oy-9/z#05 R'NC©RD K C9EEK I � �-� f-7.9' - `' Si %CBRDCK C.ftEE�N .A>ER ,uRrACE 1os7 F<U �� it '1"CM a --- -� A• 2�2D Py- oti D4I19/2-0_ STpFiT/ CUIJE?'� `T .. 1=a-2U ,^ .= If 8.'9 fi 72'CMF' STORM CULVEkT c-8.34 o IE-1217 _- 8-PVC STDRM Ism i-F4T- 4� DORE ro ~ ! - W 1YPE I jl RN 17M SP-2 E x 1I.- .c CB 7wE - I+ Ml 1354 ,•<4 RI Y 1747 SP-fi d _ fIj 8Ci 11.5A DN-2 IE S 13.41 I+ I �F ASPHALT TRAIL ® FONIO REBAR MID CJY 0.5' SOVNIE BOLLARDS M 1221 5, EOT 13.23 - SCE 27329" 1 RIY te.la ASPHALT TRAIL . .. :. . 'SEr ML loll sopK NAIL ECG . CAST EL ie60 - Fa NAIL AT XE. END ASPHA,7 FOOT '� g BDT 8.74 _ `� X 1e7.13a.M43 E 1,295,E+5.5E59 - .. BOLT EL1F 'pATTi NGR p1+" 6 wN.K 11DN I8.61 FEET ELEVATION irT ' n 165,9E6.5052 1p95,5418269 Y S!W,I FCC - -ELLOT1ON 19.57 FEE, ._ FAW 2104 E E 14.99 50' WETLAND BUF 84yY („ o e r cTMN�n� CONCRETE 9CU.E SEMI 1EMSE9151 I - ECC Y x 15.47 cIwNELED 7 ASPrPL N �.50' NWETLANp [SHE FER 1LDC ASINIALT :^ IT . 14646 E N 1 'C8 '.YFE _ E 5 IA.62 I 'RN CONCRETE srtlE SET PK NAE I� IE W 14m CIWNNELED 20 e5 'E E I&3T N 166.9fi0.5218 BE I I9.35 E 1�95,fi10.6B90 BDT I7.0 - 2-S10RT F'�EVATKM 18.90 FEET 76 E. I TLUP BOLDING 7 ND705'S0'E LIND AVENUE SW MUNI LEAD IN 1ACK IN CNCJETr DCft 1017.10 r91ND FACT( IX BEAD N CONCRCTE ND1'35'4E'L 2594.76' 06' IN CASE IhDWMNT. DOW 0.7' N CASE F(i TAEK N LEAD N- cr7Nc�00" OP OF RENTON AAONu I ND. 1Bfi1 ElEYAllm 20.00 FYLI 0.6' N CASE. CIT+ OF RFJ410N xONUEENT M0. 1551. ELEVATION 21.32 FEET NO. REVISION BY DATE IAIIR NOTES : HORIZONTAL DATUM NORTH AMERICANIWUM 83/91. HELD NORIH 01'35'48- EAST BETWEEN MONUMFNTS AT THE INTFRSECTION OF LIND AVENUE SW AND SW 3CTH ST(NOT CPFN) AND LIND AVENUE SW AND Sw 23RD ST(NOT OPEN). VERTICAL DArUM'.. NORTH AMERICAN VERTICAL OA'UM 88. HELD CITY OF RFNTON MONUMENT NO. 1861 AT THE INTERSFC71ONS OF LIND AVENUE SW AND SW 30TH 7(1 0?11 FI FVATION 20-OC FEET AND MONUMENT N0, 1551 AT LIND AVENUE SW AND SW 23RD ST(NG' OPEN) ELEVATION 21.32 FEET. DHA Bi TOP N-,RTHWEST BASE BOLT OF LIGHT STANDARD 1176 FEET FAST OF THE CENTERLINE OF SPRINGBROOK CREEK ON NORTH S1DE OF 34TH STREET SOUTHWEST, ELEVATION 18,92 FEET DH4 fili CHISEID SCJARF AT SCUIHEASI CORNER CONCRETE TRANSFORMER, 1,175 FEET WEST OF SPRINGBROOK CREEK CENTERLINE AND 12.0 FEET NORTH OF BACK OF WALK ON NORTH SIDE SOUTHWEST 34TH $ REST, ELEVATION 21.10 FEET TGPCCRAPNIC MAPPJNC NOTES' T4E MAP SHOWN HEREON IS THE RESULT OF A TOPOGRAPHIC SURVEY BY ELANE AARTMAN k ASSOC,ATES, INC- (DWI) COMPLETED CIA Ai. 21, 2005_ ALE EXISTING UTILTTIES SHOWN HEREIN WERE FIELD TIED AS A RESULT OF A UTILITY PAINT -CUT DURING THE COURSE OF THE FIELD SURVEY, DUANE HARTMAN h ASSDCMATES, INC. {DHA) ASSUMES NO I FOR THE ACCURACY OF THE UTILITY PAINT -OUT. DHA ASSUMES NO LMBILTIY, BEYOND SAT➢ DATE, FOR ANY FUTURE SURFACE FEATURE MODIFCATQNS OR CONSTRUCTION ACTNATIES THA' MAY OCCUR WRHIN OR ADJOINING THE PERIMETER OF THIS SURVEY. CONTACT OHA (425/483 - 5355) FOR STTE UPDATES AND VERIFICATIONS. LEGEND . - RDAG .EN-E3L11f 6 MONUMLN' IV CASE ,TOAD ?i^,H7-OF-A'AY Q�- PRWEC' HLNC'iMR•i'•I DLIEC Wr x f'K NAIL 'CON'RC•LJ r*NCE L.NL e RLDAR AVU CAP - CONTOUR INTERVAL (2 FEET) Y CULVER' CONTOUR INDEX (1D FEET) LT S'ORM DRAIN CATCH BASIN • STORM DRAIN CLEANOLIT RI OD DUILDING STORM DRAIN MANHOLE CLE CHAIN LINK FENCE - CONIFER TREE CONE CONCRETE DECIDUOUS TREE GNP CORRJ ED METAL PIPE a SIGN Z� ECC EXTRUDED CONERFTE CURB 0 POTHOLE 20 D 20 4D ORN ORNAMIN'AI O SANITARY 51 MANHOLE Oft ORDINARY HIGH WATER �-t UTILITY POLE WITH IIGHT stole Feet p,C POLYVINYL 'yLORIDE PIPE # LICFIT POLE SP SOIL PLOT f,Z WATER HYDRANT SDMH SIORM GRAIN MANHOLE 6I WATER VALVE SSMH SANITARY SEWER MANHOLE li WHELLCFAIR RAMP P WETLAND FLAG UTILITY POTHOLE RESULTS: DATE 05/12/2009 POTHOLE ID TAROS" UTILTT" DEPTH TO 70P OF UTLII' IN INCHES DEPTH TD DOT OF : PIPE CONDUIT UTILITY IN INCHES '', SIZE IN INCHES PIPE MATERIAL HUB EI.FVATIgN SUBSURFACE COMPOSITION PI powi-- - -- 42 69" 2 8' 2 4" PVC 11.70' ROCKY P2 POWER 41" 49' 2 8' 2 4" PVC 18.19' ROCKY i POWER 44' 71" 2 8" 2 4" PVC 18.16' ROCKY T1 TEL 37 64- 27 WIDE COF DUCT I6.44' ROCKY T2 TEL 25 51 25 99DE CDF DUCT 18.47 ROCKY T3 RE 9C 54 25 MOE COE DUCT 18.21 ROCKY GI GAS 39 43 4. PE 18.31 ROCKY 2 -ug- d m, 39 4 PET ROCKY M.5- 4" PFtA3 lb Ul NE 1/4" SR 1/4, S 25. TWP 23 N, R 4 E k NW 1/4, SA 1/4, S 30, TWP 23 N. R 5 E. W.M. CITY OF SW 34TH STREET 15 la_D5 -' REN TON CULVERT IMPROVEMENT PROJECT '"°'°°" 'L.L. FIGURE A-1 DATUM O �"` 7 7 P1aDrlmg/eD4dmg/Public works Dept. EXISTING SURVEY �. MAP -.. NIN v ch cn dI IL a PSE POWER DUCT PSE 4" CAS Co C6{P CI,'LVERT s" ss QUEST COMMUNICATION DUCT ADWAY 7 acp � NO. I REVISION SECTION SCA_EI Did/ = 5' VERT 1 "--5' CID 6Y DATE APP =,Q R CITY OF �+ RENTON �.{ DAfUM Pionning/Building/Public Works Dept_ 5 2.5 0 S 10 Sco a Feet SW 34TH STREET �Rs-ls-os CULVERT IMPROVEMENT PROJECT FIGURE A-2 EXISTING SECTION I ti i E wl=T��N4 � 80UNDP,RY--� s4' WELLAND Al BUFFER — I [W MN' WALL i UST 36" .SO CUT n LlSN W/ ___ _____—__ ~� i E E � r r-- rv'E1�f CATC�#� l � ROAD RCCON )TRSCIIOr� - -... n, - dI Ui 5N WINGWALL" N - v, r. mcl _ orrc x F- --1 WETLAND AY nuS A 1F 1 Oh'� N CH a scuE nC aw0nELr $GUNDARY n V N0. w£T4N11 50' WMAND ST / BOUNDARY PER Afo"M IN (A �J REW AND CRP C(fr42RC SWM aR4W CATCH R49m co"o YR MT % J — SMNCBROOK CREEK TRAIL SO" RECONSTRUCTION DArA saor ! ECb sapfrhRY SfAFR 4mmF ! SAWrARY SFWi"R CLEAIV Dili urrum POLE xrrri t>a+r 4 EX)ST 60STORM WATER flVVNV DRAIN. CUT FLUSH W,/ WATFN VAI VF � New WALL wNFFiclaarR . � MEiLAND fLP.f, _ { _ cw C64'RETF, CMIG CORRIATC NE7.dG lVF RELOCATED SANITARY SEYdER.Ta£f.sf ICU E oft 61%v vTk pNW CmnriRRV Nr,'H WA7FR Pali 4ti' LA �'N Ili P_, ,4i� --_ �____--_� ' ---- 3 1'riV x 1 ,•?ICN 7-A,} 1 -+- i - t?ELOC�TEL � y 12, WATER — 1 LiMiT OF ROAD f r R£CONSTRUCTiON X. tl1��1r111LLLCl1EL cane R r-of-wnr q I FNC�ff WA?t7CR MARL' j} I � VArUfRY�IXlNO G4S UNUFAr_90 V MNITARr }1}E ut r,c>rrA�_t u,�Nn sTapk 1 f WETLAND I BOUNDARY' 040ERCMLYD THIPHO& e J {, ! - iWVRCRVX WAIER � I-�rETI�ND f1➢ 50 eu�I 1z nr�� Ri75 SURL'L'Y l7EPRESFN73 77t£ Y4P4GRAPVilC FCATTtPFS SPRINGBROOK CREEK iRAIE_ AV rHf r f:risrFD Cv .S: rF As ar APf2lc 21, aoo 40. K1N(; L rarY �+ 15 Q 15 30 flRANINAGE ISTRIM RQW ` � ' � Scole feel NE 1/4, SE 1/4, 6 25, TWP 23 If, R 4 E k " 1/4, SW 1/4, S 36, M 23 N, R 5 L T.11, REVISION —CM r0. SW 34TH STREET 6-15-OS Ci Y C}F CULVERT IMPROVEMENT PROJECT ... -i RENTON `"° ,� DATUM FIGURE A-3 a03 ..r P;orn�ng/DuHCing/Pvbft Works Dert, PLAN BY DATE APPR � r � �%} 50' VC iA - - a - W � c W � 'c� U I Q 2 — U [] I I TEMPORARY CONSTRUCTION DIVERSION PIPES Z 150' VC 50' VC `o N Ln N' c o C, - lu p4 Q o Q c] U1 a�i m Q v W V] m a2 MAX GRADE RASE r 3 �2,3" W l/] W :.J m la: W F Ul } -2-0% ISTING GRADE TEMPORARY CONSTRUCTION r ` EXCAVATICN SFAWNING GRAVEL FOUNDATION MATERIAL SECTION A SCALE: HDRII 1 "=111' FIC 7 VERT 1"=1O' PEDESTRIAN GUARDRAIL SW WINGWALL ° SIDEWALK � SIDEWALK i CREEK INVERT � RELOCATED GAS - RELCCA ED COMMUNICATION DUCT BOX CULVER' BASE SECTION B SCALE: HORIZ 1"=10' FIG 7 VERT 1"-10' NO. I REVISION REI-OCATFD WATER EXISTING GRADE NW WINCWALL !� RELOCATED ELECTRICAL DUCT CITY OF RENTON I�r OATIJM �� Planning/Building/Public Works Dept. sir .un�o-a., 10 5 0 10 2C Scale Feet SW 34TH STREET a�6- s-os CULVERT IMPROVEMENT PROJECT FIGURE A-4 SECTIONS y i cC1K1iElE 3 �A-2 4 I BUFFER L �dx �bc a1, m� K O I m N Y m zi 0 m1` c� 6cUfr�'UN DA V1L1 V NU i —1 `RY-1 SURFACE PN ML X, tNON, 1, WA1K AI .." ClkFa[TE pp"Kf N lria992-0525 t1s5,75_.5No7 I� ELEVAll ,S.ez t 1 u5I F1 1167 -8 BC11 a15.a9 ASPKkT i i I� �I JII RRLK 11, 5�' w FFD WETLAND BUFFER SDAT11 Ak t9.+5 lrwnas I IFa my 48" CIA TEMPORARY DIVERSION PIPES FLOW T 72' CMP STORM CULVFRT E 8.20 _ i TEMPORARY IC 8.09— COFFERDAM 72"CUP STORM CULVERT — �cl �ftE 79' E R'„6GBROOK CRELK �� _ — I MPORARY a 2 X F.N. w!1 o+lly ms lE SPRiNG8�3DK CRkFK 1E 8,12,E �} 12"-NP STO C1iLVERi 1E=6.2G ^ COFFERDAM - . -1 IE BAD �72"CUP STORM CULVFRT --,---.--- -- -' _ _ _F 5y 45 .�.. �1 ' \ I ✓suer ,toL,� �,- � P,N i a ett :sa R,4-1. E a i.7. BOUNDARY N, ::aLN gem t3.2, s '; s j auaRt eounNus i1 nwri 0.5NhW' IVJJL rnuN- ?CLw, N.S- :h' - - � y I I E sH1 19.16 � X 'pK twL t0� 4/ j _,F�r, -- �------- - 1 1 `I Vk Y0. 10 T6 1 NOT 9.74 CAS-1 EL 19.50 } ACE NVF E1J7 AjprWl E¢l1T 1 - - -' e%LY E�6r aK,N vEW eFcx. Ur '." N 166,986.a054 llj { 54"269 I �� aL� •+� � - �� � I - _ " E,svi911t`Jw 1e51 RE[ I 517` WI 460 BUFFER Cl. {! WEILANJ { i BUfFEft ^%� ��ivss `I LudC" scxE SS.i3 E N 15.47 I ELM A f6f°1u`-1 c C" SC&I ar,wrElio 1 � 4 R SET PK PAL N 5ib,9aUS718 I E I,.6t7RN9L' ELEYATK7N 18,90 IFFY X I I� I I j ryg1 181! 1�s4 ,o NOT -S TN15 SUAVFY R£'PFES&V75- TNF 70POC4APHIC FLATt/RL5 As 7NEY EXfSTE, oh' SITE AS OF APRIL 2T, 2005, 2a a zo ao Scale Feet PLAN SCALE: 1 "=ZY -- — �n ts1 - E 1295M9 5MR vu RE rE WETA"IQ ILE 50' NWETAJ,6 BUFFER cs rnEI I mm 20.65 4 E E 58.3i \ Jr" 1a.35 9pT 17.PS \ Tno'Tc SAS4m i { �oT 'LAN lo DVCRTIFLOWS N SPRINGbRCO SCHEMATIC ICREEK. FINAL P ANARILWlIY RE DESi5NED By THE CANTRACTOR. NN' 1/4, SE 1/4, S 25, TWP 23 N, R 4 E & Nl< 1/4, SW 1/4, S 36, TFP 23 N, R 5 t, rt.A. —71E5-'5-DS sW 34TH STREET CITY OF CULVERT IMPROVEMENT PRWECT RENTD`~1 FIGUREA-5 E�A TEMPORARY DIV€RS*% KM - NN NO. REVlSIOh _J_� —��- I WET( AND BOUNDARY 50' WETLAND BUFFER W WINGWALL � r EX'ST 36" SD f CUT FLUSH W/ + 1 NEW 'HALL ',' AD RECONSTRUCTION _ N E 0 AV NEW CATCH HASINS i,,T KAD LC'Y1 FC'JT PLANTING SCHEDULE SYMBOL I SCIENTIFIC NAME COMMON NAME SPACMC QUANTITY !"t `�.l POPulus BAL31FERA BU4K CoOTOW M 0 SPP. TRICHOCARPA N0 i C SALIX SITCNfNSIS sITKA NIL10N 4' G.C. 20 ODRNUS STOLONIFERAA RED -OSIER UGGWOOD 1 4' 0 G 4 SEED MIX SCIENTIFIC NAME COMMON NAME SR % COVER QUANTITY VM. R FESTUCA RUM 19FA FESCUE 301E 0.2 LBS ACRE CAJi17( S'IPATA SAWBfNf SEDGE 407E O.t IBS ACRE CAREX OEREYANA KWCM SEDGE Wx PA LBS ACRE N ONE INCH AT FULL SC> ONE MCH SCALE ACCORDINCLY 1 �r r SW WINGWALL 50' 1 WETLAND - f BOUNDARY 1 Jones &r Stokes x I WETLAND BOUNDARY r r Ii 1 50' WFTLAND V`61FER r / 5PRINCBP,DOK CREEK TRAIL RECONSI RLJCT10N Planti.ng_Notes. 1. Seed mix to be hydroseeded over all wellond and wetlond buffer areas to be disturbed by mitlgo6on activities including planting and installation of rootwods. 2. Rootwads shall be anchored prior to planting. 3. Willow species to be planted as 60" dormant cuttings. A. Dogwood species to he planted from 1-gallon size containers. S. Block Cottonwood shall be minimum 6' in height, multi -branched, with single, dominant leader. 1 c�U t LEGEND �, NE W'NGN'ALL Mo+vuMExr w c45f EXIST 60" STORM RFhAR AND CAP DRAIN, CUT FLUSH W/ COLVERT NEW WALL STORM OWN CATCH BASIN STORM OWN MANHOLF W W cnNrEEA REE oecrnuous TRce - — RELOCATED SANITARY srsN SEWER, SEE FIGURE E [MIA F101 f - f ._. - - _ .. SOh SA APr 5FW, R MAh'r+v� f j I y 1f 1 I SIN A'. r SFYY'rR C rF.N OUT i �. 1 40' KING C NTY DRAINAGE (STRICT Row ­ V11'1FxI; — — POINT urn„ All , WTH 116H, !16'NTPJLC I WATER VALVE _ KFI .�'C °: '�EL� 12" WATER � !Yh'FFiCFWR RAMP�- LIVIT OF ROAD WETLAND FLAG f RECONSTIRKTION Brut _ c�c 'rf CONCREc COxCRE -- _ - - COR1G. COAAfG+17fU MFTA1 flPE URN ORNIM£NrA1 - y{ : - OHW OR' Y "" WATER _ - _ PKG PCLYKNA1 CHIORIOf PTPf ® ® SP Soli PLOT 50MH STGRM DRAIN MANHOLE ` l ssmN SnmTMY SEWER AwHctc It ROAO CENTERLINE 1 r RONO RIGHT-OF-WAY ' BUfILWNC ' SE W_ INGWALL_ FEV7 TrNF WETLAND — - HICH WATER MARK_ B_C_JNDAR'Y UNDERGROUND GAS ONDERCROUNO FLFCTRIC ---- ' WFTLAND UNDERGROUND VNYTARr BUFFER UNDERGROUND STORM UNDERGROUND TELEPHONE SPRINGBROOK CREEK TRAIL UNDERGROUND WATER NOTES 15 0 15 30 THIS SURVEY REPRFSENrS THE TOPOGRAPHIC FEATURES As THEY ExISTEo ON S)TF AS OF APRIL 21, 2005. scale Feet NE 1/4, SE 1/4, S 25, T?rP 23 N, R 4 E k KW 1/4, SR 1/4, S 30, T" 23 N. R 5 E, W.M. DATUM rr�c CAD No. BY REVISION CITY OF SW 34TH STREET 12 �14f a5- CULVERT IMPROVEMENT PROJECT E {��, FIGURE A-6 Planning/Building/Public works Dept. PLANTING PLAN Appendix B 'ish Exclusion Guidelines Appendix B: Fish Exclusion Guidelines B.1. Fish Removal and Relocation and Stream Dewatering Protocol Prior to work adjacent to or over Project creeks, a fisheries biologist will walk the stream reach immediately above and below the work site and conduct a visual survey for fish. Should fish be observed to be present, work will cease until they can be removed from the area. No ESA -listed species are likely to be present during the anticipated timing of the Project (late summer/low flow). Prior to dewatering the site, aquatic life (all vertebrate species) are removed and relocated out of the work area. Fish exclusion is done under the supervision of environmental support staff. The sequence for fish exclusion is as follows: ■ Isolate the area (block nets) upstream and downstream. ■ Remove as many fish as possible using seine or dip nets. ■ Gradually dewater the work area. ■ Remove as many remaining fish as possible using dip nets. ■ Electroshock, if required by permit, to avoid any stranding. Any permit specifying electroshocking will be reviewed by NOAA FisherieslUSFWS in accordance with the draft Memorandum of Agreement establishing fish removal and relocation protocols (National Marine Fisheries Service 2000). • Keep records of fish exclusion activities. • Fish and other wildlife removal from the work area is allowable under a special relocation permit required by WDFW, which includes several conditions Appendix 8 intended to minimize harm to fish. A copy of the permit must be in the possession of any persons authorized to collect wildlife, food fish, and/or shellfish. ■ In order to reduce any impacts to the affected species that are handled during this process, several techniques arc used. Removal of fish and other vertebrates will follow these basic steps: B.1.1. Isolate the Area Install block nets at up and downstream locations to isolate the entire affected stream reach. Block net mesh size, length, type of material, and depth will vary based on site conditions but will be installed to block fish and other aquatic wildlife movement into the work area. Generally, block net mesh size is the same as the seine material (9.5 millimeters stretched). These block nets are then left in place throughout the period of work and checked regularly to ensure that they are functioning properly. Crew supervisors, leads, and/or crewmembers following initial oversight by environmental staff may check these nets. Block net locations require leaf and debris removal to ensure proper function. The amount of leaves and other debris collected on the net will determine how often the nets need to be checked. An individual must be designated to monitor and maintain the nets. Block nets arc installed securely along both banks and in the channel to prevent failure during unforeseen rain events or debris accumulation. Some locations may require additional block net support such as galvanized hardware cloth or additional stakes or metal fence posts. 6.1.2. Fish Removal and Dewatering Once the stream reach has been isolated, all attempts to remove fish and other aquatic life are made in a manner that involves the least amount of handling. Aquatic life is captured by hand or with dip nets and immediately put in dark -colored 5-gallon buckets filled with clean stream water. ■ Fish screens will be used around pump(s) so fish are not sucked into pipes and diversion pipe(s). Pumps shall not cause impingement on the screens. ■ The stream will be dewatered in two or three stages to allow fish within dewatering section to leave with lowering water. ■ All available methods will be used to capture fish within the section of the stream to be dewatered. * Seining should be first used to capture fish within the stream. This method may not work if substrate is large, reach contains deep pools, or if there are undercut banks or heavy vegetation. a.s Appendix B Electrofishing should be conducted after seining. A minimum of three electrofishing passes should be conducted until no fish are caught or observed. The following are measures to minimize impacts to fish during electrofishing. — NOAA Fisheries and USFWS in Lacey, Washington, will be provided written notification 10 working days prior to the initiation of electrofishing. — All capture, retention, and handling methods shall be implemented at times that will avoid temperature stress of fish being sampled. — All collection and sampling methods shall be implemented at times that will avoid disturbance of spawning fish. Any purposeful take of fish that are actively spawning or are near fish spawning sites is prohibited. — Electrofishing will be conducted following the NOAA Fisheries' June 2000 Backpack Electrofishing Guidelines or WDFW Electrofishing Guidelines. — Electrofishing will be conducted only by qualified and experienced individuals. A minimum of four individuals will be used for electrofishing. — Electrofishing anodes will not be used as nets. Injury and/or death can result from fish being exposed to the electrodes. Separate nets will be used to capture fish. ■ If fish are captured or handled: — All live fish captured shall be released as soon as possible and as close as possible to the point of capture. — The period of time that captured fish are anesthetized shall be minimized. The number of fish that are anesthetized at one time shall be no more than what can be processed within several minutes. — If fish are held, a healthy environment for the stressed fish must be provided, and the holding time must be minimized. Water -to -water transfers; the use of shaded, dark containers, and supplemental oxygen should all be considered in designing fish handling operations. — Prior to conducting activities that may involve handling fish, individuals shall ensure that hands are free of sunscreen, lotion, or insect repellent. B.7.3. Information Logs Each species and year class is recorded in bound field notebooks. Year class designations will be used to allow a rapid estimate of length to minimize fish handling time. Salmonids with fork lengths approximately 60 millimeters or less will be classed as 0+ age fish, and fish over 60 millimeters will be classed as 1+ age fish. In addition to the species information, field notes will also include other information such as date, personnel, time, general site conditions, weather, stream temperature, conductivity, length of stream reach, methods used, and any other general comments. Data collected is used for research purposes, and clear/concise documentation is important. B3 Appendix B B.1.4. Fish Release All collected specimens are to be released unharmed upstream of the isolated stream reach. Appendix C Photographs of the Project Area Photo 1. Inlet to SW 34, Street culvert from left bank. Photo 2. Inlet to SW 341, Street culvert from right bank. Photo 3. Outlet to $W 34m Street culvert from right bank Photo 4 Outlet to SW 3411 Street culvert from left bank. Photo 5. Northwest corner of the site from the south side of SW 3411 Street. Photo 6. Northeast corner of the site from the south side of SW 3411 Street. M s i, Photo 7. Southeast corner of the site from the north side of SW 34" Street. Photo 8. Southwest corner of the site from the north side of SW 34� Street. Photo 9. Springbrook Creek upstream from SW 341� Street 77 Vl i W",,. Photo 10. Springbrook Creek downstream from SW 341, Street. Appendix D NOAA Fisheries and US'PA'S Species Listing Information Endangered Species Act Status of West Coast Salmon & Steelhead ' Current Proposed Salmonid Evolutionarily Significant Unit I Endangered Endangered ESA Listing Actions Species (ESU} Species Act Species Act Under Review Listing Status' Listing Status l Snake Ri%_c.i FSU Sockc 'e Salmon I (Oncorhynchus. 2 Ozette Lake HSU nerka) 3 I3aker River FSU Not Warranted 4 ( Qb-,jp Egan River ESU Not Warrunted 5 I Lake Wenatehce ESU Not Warranted 6 Quinali lake ESU Not Warranted I I 7 Lake Pleasant ESU Vol Warranted 8 Sacranmito,.River Winter-nni ESL' it rt i�eret 1 9 Upper Cblumbio Rivet' Snring.run_ESU Endangered Chinook Salmon 10 � .Shake River S1i-in ,Stulinler-rtin ESU Threaleire (O. tshawytschu) 1 I Snake River Fall -run ESU Threate 12 Pu€ et Sound ESU Threate� 13 1-uwcr Colombia ItivcrESlJ i lipThreatened, I 14 Unper Willamette River 1=SU .� Threatened 15 Central Valley Spring -nun ESU Tl:realriaed.. 16 California Coastal ESU m: „Tkom 17 Central Valley Fall and Late Fall -run ESU Species of Concern 18 Uppg'.Klaniath-Trinity Rivers ESU Not Warranted 1 19 Oregon Coast ESU Not Warranted 20 Washineton Coast ESU Nat Lf'urrunted i 21 Middle Columbia River spring-nin FSU Not Warranted ! 22 1.:pi,crColunibiaRiver ,uminer/fall run F5i Not FVarranled Southern Orci;on and Northern Calitbrni;€ I 23 FSUNot Warruntcd 24 Deschutes River sunimer/rt111-nrn ESL! Not War•rutatcd 25 I Central Calilornla Coast ESU 26 Southern Oregon Norther❑ C'alilurnia ESU _--- -- _. Threatened Cohn Sahnun Propom-if • ESA Listing Status, (O. kisutch) 27 Oretgoii Coast ESU Threate'neil Critical Habitat Designation i 28 Lowcr Columbia River ESU 29 Southwest washington FSU 1 Xot biarranlecl 30 i Pt_t M Sound?Stra.it_ ofCeorgia FSU Species ofCeizeern 31 C)1 'ill le PL'111n5lika FSU Not fvarrarrted ('hunt Sal l»un 32 I f load Canal SEIm111e1'-run ESU Threatened (O. keta) 33 Cnluritbia Rivcr FSU ,_.,—Threaten 34 I'uget-.Soil Ild/Straitol'Cicor*ia 1_5U Not J1'urranted 35 Pacific Coast 1iSU ,Vol Warranted 36 Siruthcrn C' €hfornisl I:SL! • ESA Listing; Status O. rnykiss 37 i UpperC_'olumhia River Ftil-i • ESA Listing Status i (sieclhrld) 38 ('enlral ['sslil'urnia toast I:SU • ESA Listing Status � 39 I South Central C'alirorlria Coast ESU Th • ESA Listing Status 40 Snake River Basin ESU Tlitcrlterikrl • ESA Listing Status .. .,.. 41 Lower Columbia River ESU• ESA Listing Status 42 i California CcnIraI VnIIey_E S-U Threatened • ESA Listing Status i 43 I U )per WilEamette River ESL' itr�er! ESA Listing Status 44 Middle Columbia River ESU ESA Listing Status 45 Northern Calilbrrlia ESU ESA Listing Status 46 Oregon Coast ESU. 1neeies of (o"cern '. j I i 47 Sot€thwest Washington ESU I Not Warranted 48 O'.nipic Peninsula LSU Not t'yarramed 49 I i'u�: ct Sound ESU Mot War-r•crrrtec( • ESA listing status 4 6 50 Klamath Mountains Province HSU Mol liarrawed Pink Salmon 151 Evcliyear "Vol lfarrunted (O. gorhuschcr) 52 t ldd- 'car Not Pvorrunted An Evolutionarily Significant Unit, or "ESU", is a distinctive group of Paci fie salmmon or steelhead. NOAA Fisheries considers an FSU a "species" under the ESA Updated final listing determinations for 16 salmon ESUs were issued on June 28, 2005 (70 FR 37160). On September 2, 2005, we issued final critical habitat designations for 19 West Coast salmon and steelhead ESUs (70 FR 5248X and 5=630). The final listing determinations for the Oregon Coast coho ESU and ten Orrcovirl rrchus ntykiss ESUs have been extended for 6 months until December 12, 2005. See the announcements published in the Federal Register on June 28, 2005 (70 FR 37217, and 70 FR 37219). A petition to list Puget Sound steelhead was received on September 13. 2004. The ESU is currently under review. littp://w;w.M.gov/westwafwo/se/sejist/KING.htm LISTED AND PROPOSED ENDANGERED AND THREATENED SPECIES AND CRITICAL HABITAT; CANDIDATE SPECIES; AND SPECIES OF CONCERN IN WESTERN WASHINGTON AS PREPARED BY THE U.S. FISH AND WILDLIFE SERVICE WESTERN WASHINGTON FISH AND WILDLIFE OFFICE (Revised October 8, 2004) KING COUNTY LISTED Wintering bald eagles (Haliaeetus leucocephalus) occur in the county. Wintering activities occur from October 31 through March 31. There are five bald eagle communal winter night roosts located in the county. There are two bald eagle wintering concentrations located in the county along the Skykomish- Bt- '-ler-Tye Rivers and Foss River. There are 38 bald eagle nesting territories located in the county. Nesting activities occur from about January 1 through August 15. Bull trout (Salvelinus confluentus) occur in the county. Canada lynx (Lynx canadensis) may occur in the county. Gray wolves (Canis lupus) may occur in the county. Grizzly bears (Ursus arctos = U. a. horribills) may occur in the county. Marbled murrelets (Brachyramphus marrnoratus) occur in the county. Nesting murrelets occur from April 1 through September 15. Northern spotted owls (Strix occidentalis caurina) occur in the county throughout the year. M,-;or concerns that should be addressed in your Biological Assessment of project impacts to lis._.t species include: 1. Level of use of the project area by listed species. http_I/www,fws.goy/westwafwo/se/sc_lisUKINCi.htm (l of 3)1 l/29/2UU5 3:34:29 AM http://www.fws.gov/westwafwo/se/se—list/KING.htm r 2. Effect of the project on listed species' primary food stocks, prey species, and foraging areas in all areas influenced by the project. , 3. Impacts from project activities and implementation (e.g., increased noise levels, increased human activity and/or access, loss or degradation of habitat) that may result in disturbance to listed species and/or their avoidance of the project area. Arenaria paludicola (marsh sandwort) may occur in the county. Castilleja levisecta (golden paintbrush) may occur in the county. Major concerns that should be addressed in a Biological Assessment of listed plant species include: 1. Distribution of taxon in project vicinity. 2. Disturbance (trampling, uprooting, collecting, etc.) of individual plants and loss of habitat. 3. Changes in hydrology where taxon is found. DESIGNATED Critical habitat for the northern spotted owl has been designated in King County. Critical habitat for the marbled murrelet has been designated in King County. PROPOSED Critical habitat for the bull trout (Coastal -Puget Sound distinct population segment) has been proposed in King County. CANDIDATE Fisher (Martes pennanti) (West Coast distinct population segment) Yellow -billed cuckoo (Coccyzus americanus) httpa/www.fws.gov/westwafwo/se/se_iisdKING.htm (2 of 3) 11/29/2005 3:34:29 AM hltp://www.fws.gov/westwafwo/selse—lisVKING.htm fk SPECIES OF CONCERN Be,.cr's ground beetle (Agonum belleri) California wolverine (Gulo gulo luteus) Cascades frog (Rana cascadae) Hatch's click beetle (Eanus hatchi) Larch Mountain salamander (Plethodon larselli) Long-eared myotis (Myotis evotis) Long-legged myotis (Myotis volans) Northern goshawk (Accipiter gentilis) Northern sea otter (Enhydra lutris kenyoni) Northwestern pond turtle (Emys (= Clemmys) marmorata marmorata) Olive -sided flycatcher (Contopus cooperi) Pacific lamprey (Lampetra tridentata) Pacific Townsend's big -eared bat (Corynorhinus townsendii townsendii) Peregrine falcon (Falco peregrinus) River lamprey (Lampetra ayresi) Tailed frog (Ascaphus truei) V y silverspot (butterfly) (Speyeria zerene brerneri) Western toad (Bufo boreas) Aster curtus (white -top aster) Botrychium pedunculosum (stalked moonwort) Cimicifuga elata (tall bugbane) http://www.fws.gov/westwafwo/se/se_list/KING.litm (3 of3)11/2912005 1:34:29 AM SW 34th Street Culvert Replacement Project ■ R.W. Beck Associates ■ February 2006 MAR 2 3 2006 8ECEIV&D III Janes & Stokes Conceptual Wetland Mitigation Plan SW 34t" Street Culvert Replacement Project Prepared far; R.W. Beck Associates 1001 4th Avenue, Suite 2500 Seattle, WA 98154-1004 Contact: Michael Giseburt, P.E. Prepared by Jones & Stokes 11820 North up Way, Suite E300 Bellevue, WA 98005 Contact: Andy Wones 4251822-1077 February 2006 This document should be cited as: Jones & Stokes. 2006. Conceptual Wetland Mitigation Plan. SW 341 Street Culvert Replacement Project. February. (J&S 05287.05 ). Bellevue, WA Prepared for R.W. Beck. Table of Contents Introduction................................................................................ 3 ProjectImpacts.......................................................................... 3 Project Mitigation....................................................................... 4 MitigationGoals.................................................................................4 Mitigation Objectives.........................................................................5 Mitigation Sequence..........................................................................5 Avoidance. .............................................................................. 5 Minimization...........................................................................5 Restoring Temporary Loss.....................................................6 Compensation........................................................................6 Monitoring and Maintenance..................................................6 Performance Standards. ......................................................... 7 References.................................................................................. 8 SW 3V Street Culvert Replacement ^,` Tables Table 1 SW 3411 Street Culvert Replacement Project Wetland Impact Areas (square feet)........................................................................................................... 4 Figures Figure1..........................................................................................Follows Page 8 Acronvms OHWM ordinary high water mark Project SW 341h Street Culvert Replacement Project RMC Renton Municipal Code RM. Beck Associates (05257.05) ,� Introduction This wetland mitigation plan was prepared to address wetland impacts associated with the SW 30 Street Culvert Replacement Project (Project) proposed by the City of Renton (Jones & Stokes 2005a). The Project's wetland delineation report (Jones & Stokes 2005b) identified the following two wetlands associated with Springbrook Creek in the Project vicinity: Wetland 1, located upstream, and Wetland 2, located downstream of SW 341h Street. The purposes of the Renton Municipal Code (RMC) wetland regulations are described in RMC Chapter 3, Section 4-3-050.A.7: "Wetlands: The purposes of wetland regulations are to: a_ ensure that activities in or affecting wetlands do not threaten public safety, cause nuisances, or destroy or degrade natural wetland functions and values; and b. preserve, protect, and restore wetlands by regulating development within them and around them; and c. protect the public from costs associated with repair of downstream properties resulting from erosion and flooding due to the loss of water storage capacity provided by wetlands; and d. prevent the loss of wetland acreage and functions and strive for a net gain over present conditions (Ord. 4851, 8-7-2000; Ord. 5137, 4-25-2005)_" Project Impacts The Project will result in a net increase in wetland area since the proposed culvert will result in removal of the existing culvcrts and concrete at the inlet and outlet and replacement with a shorter structure. Wetland area will also be gained on the west side of the channel where the banks will be excavated and root wads added to enhance instream habitat. However, although the net effect of the Project will be an increase in wetland area (approximately 600 square feet [0.01 acre]), there will be a temporary impact to SW 345 Street C;aU,,r, W i laceme, Y:� f; wetland and wetland buffer area associated with ground disturbance. Affected areas of wetlands and associated buffers are shown in Table 1. Table 1. SW 34th Street Culvert Replacement Project Wetland Impact Areas (square fleet) Wetland Wetland Area Below Wetland Area Above Wetland Buffer OHWM OHWM Wetland 1 - Prior to 2,593 290 3,544 Construction (existing area) Wetland 1 - During 2,593 290 3,544 Construction (Temporary Impact) Wetland 1 - Following 2,893 290 3,544 Construction (new area) Wetland 2 - Prior to 2,448 0 2,843 Construction (existing area) Wetland 2 - During 2,448 0 2,843 Construction (Temporary Impact) Wetland 2 - Following 2,748 0 2,843 Construction (new area) Total Permanent Gain +600 0 0 following Construction Note: OHWIA = ordinary high-water mark Project Mitigation The project will not result in a loss of wetland area, but will actually increase wetland area. Areas that are temporarily disturbed during construction will be replanted with native wetland vegetation, restoring or enhancing wetland function. Therefore, the project will require no compensatory mitigation. Project mitigation described in this plan is intended to achieve the following goals and objectives. Mitigation Goals The goals of this conceptual mitigation plan are to: ■ restore currently degraded wetland and stream buffer, and ■ enhance instream habitat of Springbrook Creek. R.W. Beek Associates (05287,05) SW 34�1 Street Culvert Replacement Project Mitigation Plan Mitigation Objectives 'rhe objectives of this plan are to: • increase stream habitat area by replacing the existing culvert with a shorter culvert, ■ remove invasive vegetation within wetland and stream buffer and replant with native herbaceous, shrub, and tree species, • grade and stabilize the streambank, and ■ enhance instream habitat value by installing, root wads in created alcove pools and planting adjacent banks with overhanging woody species. Mitigation Sequence Mitigation follows the following mitigation sequence (from RMC Chapter 3, Section 4-3-050.M.8): a. avoid any disturbance to the wetland or buffer, b_ minimize any wetland or buffer impacts, C. restore any wetlands or buffer affected or lost temporarily, and d. compensate for any permanent wetland or buffer impacts. Avoidance Due to the nature and location of the Project, it will not be possible to avoid impacts to wetlands and wetland buffers. Minimization Impacts to wetlands and wetland buffers will be achieved through the following measures. ■ The use of equipment in wetlands and streams will be confined to the minimum area necessary to construct the Project. This area will be outlined on construction drawings. ■ The limits of construction will be staked, fenced, or flagged as no -work areas to minimize temporary impacts from construction equipment. ■ Temporary erosion and sediment control measures and a Spill Prevention, Control, and Containment Plan will be in effect to ensure conformance with requirements of the City of Renton, the Washington State Department of Ecology, and the U.S. Army Corps of Engineers. 5 February 2005 SW 34`h Street Culvert Replauw!l ; � rc3c • Contaminants associated with construction equipment (e.g., lubricants, fuel) will not be allowed to enter wetlands. The construction contractor will provide a Spill Prevention, Control, and Containment Plan that designates equipment refueling areas that are designed to contain any fuel spills and isolate them from streams and wetlands. Restoring Temporary Loss The Project will result in temporary disturbance of 5,041 square feet (0.12 acre) of wetland below OHWM (stream habitat), 290 square feet (0.01 acre) of wetland above OHWM (palustrine emergent habitat), and 6,387 square feet (0.15 acre) of buffer habitat. This disturbance will be restored by the following measures: ■ invasive nonnative vegetation will be removed; ■ all disturbed areas above the active (wetted) channel will be replanted with native herbaceous, shrub, and tree species in the wetland and stream buffers; • disturbed areas in the roadway vicinity will be hydroseeded for rapid revegetation; • the stream channel will be widened to form alcove pools on the west bank upstream and downstream of SW 34"' Street; ■ root wads will be installed in the constructed alcove pools to enhance instream habitat value; and • overhanging vegetation will be planted adjacent to the alcove pools to provide shade, cover, and bank stability. Figure 1 shows planting locations, species, quantities, and details. Compensation Because wetland and buffer impacts will be limited to temporary impacts that can be restored, no compensation will be required. Monitoring and Maintenance A monitoring and maintenance program will be developed to evaluate the success of the project and determine if the goals and objectives are being met. Mitigation monitoring will be according to the following 2-year schedule: • at the time of construction, • 30 days after planting, • early in the growing season of the following year, • at the end of the growing season of the first year, R-& Beck Associates (05287,0) -- n SW 34" Stroet Culvut i placpmemt Prajeut Mitigation Plan ■ early in the growing season of the second year, and ■ at the end of the second growing season. Sampling sites will be established to determine survival rates. If mitigation fails, measures will be taken to correct the mitigation problems. Performance Standards Performance standards for plant survival and community composition are critical to evaluating the success of this mitigation project. The performance standards listed below are for the wetland enhancement area to rectify wetland and stream buffer impacts. All performance standards were determined from the best professional judgment of qualified biologists. For this project, the following performance standards have been established to meet the mitigation objectives_ Plant Survival At the end of the first year, 100% of the total number of plants installed should be surviving. The contractor installing the plants would be responsible for replacing all plants that die. Plants that die would be replaced with native species that appear to be best suited for the site to maintain the 100% survivorship. Any replanting would use several different species to maintain plant diversity. At the end of year 2, at least 80% of the planted and desirable volunteer species should be surviving. Desirable volunteer species (i.e., native shrubs and trees) would be counted toward the number of live plants. Sfreambank Conditions As part of the monitoring plan, streambank conditions will be examined_ "As built" construction plans will be drawn and used as a basis for determining streambank stabilization success. Over the 2-year monitoring plan, photographs will be taken from designated points to visually document the streambank conditions. Success determination will be based on bank conditions, such as vegetation success and density, slope, and bank movement. 7� _.' . February 2006 SAI3' ;3�rset3"ietcxul�c�r B37t;�rr_.iar: References Jones & Stokes. 2005a. SW 34"' Street Culvert Replacement Project_ Joint Aquatic Permit Application (JARPA). Bellevue, WA. (J&S 05287.05 600). Prepared for R.W. Beck and the City of Renton. December. Jones & Stokes. 2005b_ SW 34`h Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Technical Memorandum. Joint Aquatic Permit Application (JARPA). Bellevue, WA. (J&S 05287.05 600). Prepared for R.W. Beck and the City of Renton. December. R.W. Beck Associates (05287.05) n Figure 1 . Planting Plan Figure 1. Planting Plan f 50' WETLAN[}'/ P€antina Notes 1. Seed mix to he hydroseeded over all wetland and BUFFER �FIG �' f wetland buffer areas to be disturbed by mitigation activities including planting and installation of rootwads Ord placement and removal of temporary creek bypass `. pipes WETLAND j 2. Rootwads shall he anchored prior to planting, BOUNDARY 3 Wllow species to be planted as 60" dormant cu ttings gs- ' 4 Dogwood species to be planted from 1-gollon size containers, Black Cottonwood shall he minimum 6' in height, - mat SPRINGBROOK CREEK TRAIL h-brgnchL , with si leader. ominani d Ingle d RECONSTRUCTION — NE VJINGWALL LEGEND EXIST 36" SD l . 'OUT FLUSH W/ `: -- -, _ _f EXIST 60" ST M s Mo1uM£xr AN rts£ NEW WAt1 i DRAIN, CUT FLUSH W/ R£RAR AM CAP NEW WALL CIA Vf-RT F l <f sroRu ORA1N CATCH aasw 30' WIDEx1 D HIGH 5"M LVA1N MANHOLE BOX CULVERT 1,?Cr � . DEC1Df10V5 TREE .......'-_ i_ I S — RELOCATED SANITARY SEWER, SEE FIGURE b DATA Plar c SANITARY SEWER AMNtY&C NEW CATCH RASI f5 VNITARY';1WFP Ct£,w our AT ROAD I Ot"I Pl')IN I — -- — /• ���_ �.�� ��� --- NE+�� T H'Al" N" �;l 10W rrrr POLE WITH trc r PC,) D POIN i rxr Pnc£ OF f .; WHEEL0140? RAMP ROAD RECONSTRUCTION _ _ - �_:. _ I � `: LIMIT OF ROAD %� RECONSTRUCTION ` t3r.x w£rDwD £LAG auiLOmrc � / .._. -._. _..... t_- ._ CONC CONCRETE _._. _ - ...._. - ...... CORIG CORR1GAr£D AVAL PIPE _ I . ~-` 5W WINGWALL OwORDINA1'r H1CH WATER - I ... .. "_ PVC fYJLrnwtt CNLLIAR£ PIPE u-•; � .....,. �.�_ ..._ SP SOS PLOT I i RFLOCATLD SDMH STORM DRAIN HWHOLF PLANTING SCHEDULE SYMBOL SCIENTIFIC NAME COMMON NAME I SPACING I QUANTITY - POPULUS BALSAMWERA EPP- TRICHOCARPA BLACK COTTONWOOD NA 2 Wx SITCHENSIS SITKA WILLCW 4' C.C. 20 CORRUS STOLONIFERA RED-CSiER DOGWOOD a' Q-c- S SEED MIX SCIENTIFIC NAME COMMON NAME :L COVER QUANTITY FESTUCA RUBRA VAR. RUBRA RED FESCUE 308 15 LBS ACRE CARET{ STIPAT0. SAWBLAK SEDGE 40% 12 LBS ACRE CARER DEWEYANA DEwEr SEDGE 20% 12 LBS ACRE r -- 12 WATER SSMH 54NITARY SEWER 1lA50101E Rao CENTERLINE r j i ... ...... ROAD RaCHl_pF-WAY Rija'o c FENCE LINE }s6N WATER WRK • WETLAND............ ........ ............. CAS BOUNDARY -SE WINGWALL uNa£RCRouNo - ! UND£RGROOND ELECTRIC 54'` }DING ,COUNTY WETLAND ux0£RCRouNO sWrARY DRAINAGE ONOCRGRO" SNOW DISTRICT ROWAIGROLAW GBROOK CREEK TRAIL UNO UNDERCAOUNO WnL SPr£R _ 4D' 'EPHONE WETLAND T. j IN f J s - -` ! . I NO TES I ` 5 1OUNDARY _ i 15 0 t5 30 • - - _ I THIS SUPV£Y REPRESENTS THE TOPOGRAPHIC F£ArURF5 7■■■, =� I I ■ AS THEY EXTSrED ON SITE AS OF APRIL it, 2005- $Cole Feet 1 NE 1/4. SE 1/4, 5 25, TWP 23 N. R 4 E k XV 1/4, SW 1/4, S 30, TWP 23 N, R 5 E, 1f.li. "=rO ONE —_ - ,�,e, +. I'=30' „� CITY CE SW 34TH STREET i2-14-05 fNLN .�.� �hA ��� RENTQN CULVERT IMPROVEMENT PROJECT Al fact sat[. If NOr ONE r,CH W FIGURE 1 SCALE DAruM AYORNNCLY Jones & Stokes 0REVISION Planning/Building/Pu61ic wanks Dept. PLANTING PLAN N. RSION BY DATE APPR � Pre -Design Report SW 34th Street Culvert Replacement Project City of Renton Surface Water Utility November 2005 Pre -Design Report SW 34th Street Culvert Replacement Project City of Renton Surface Water Utility November 2005 CERTIFICATION PAGE SW 34th Street Culvert Replacement Project City of Renton. Renton, WA The engineering material and data contained in this Pre -Design Report were prepared under the supervision and direction of the undersigned, whose sea] as a registered professional engineer is affixed below. S. G o Ww w EXPIP.ES; 12 - 04 - O(o r „ Michael S. Giseblik Project Manager COPYRIGHT 2005, R. W. BECK, INC., ALL RIGHTS RESERVED. R. W. BECK SW 34TH STREET CULVERT REPLACEMENT PROJECT Table of Contents Certificate of Engineer Table of Contents Tables Figures Appendices Section 1 INTRODUCTION Background........................................................................................................1-1 Authorization......................................................................................................1-2 Scope..................................................................................................................1-2 Acknowledgements............................................................................................1-2 Section 2 SITE INVESTIGATIONS AND CONDITIONS Surveyingand Mapping.....................................................................................2-1 Wetland Delineation and Stream Reconnaissance.............................................2-1 Geotechnical.......................................................................................................2-3 Traffic and Springbrook Creek Trail..................................................................2-3 Section 3 ALTERNATIVE ANALYSIS Introduction....................................................... ....... ..................................... ..... 3-1 Project Objectives and Preliminary Design Criteria ....................... ..........3-1 Descriptions of Alternatives...............................................................................3-3 Alternative 1 —Double 30'X7' Box Culverts...........................................3-3 Alternative 2 — Single 30'xl0' Box Culvert .............................................3-4 OtherOptions...........................................................................................3-5 Alternative Comparison.............................................................. ....................... 3-6 Hydraulics.................................................................................................3 -6 Structural..................................................................................................3-8 Cost 3-9 Construction Impacts..............................................................................3-10 Utilities...................................................................................................3-10 Controlof Water.....................................................................................3-10 Environmental Impacts . ..........................................................................3 -11 Recommended Alternative...............................................................................3-12 Working Final Report. doc 11/21/05 Table of Contents Section 4 RECOMMENDED ALTERNATIVE Introduction........................................................................................................ 4-1 Traffic and Springbrook Creek Trail.................................................................4-1 Dewatering/Diverting Springbrook Creek.........................................................4-2 Rights -of -Way and Easements...........................................................................4-3 Utility Relocations.............................................................................................4-3 Culvert Foundations...........................................................................................4-4 Road and Sidewalk Modifications ................................................ ..................... 4-5 Environmental Considerations...........................................................................4-5 Potential for Scour or Sediment Deposition......................................................4-6 Potential for Contaminated Sediments...............................................................4-6 Permits and Regulatory Issues...........................................................................4-7 Schedule... ...... ................................................................................................... 4-7 Section 5 REFERENCES Tables Table 1 Hydraulic Performance of Existing SW 34 h Street Culvert and Culvert Replacement Alternatives.................................................................3-7 Table 2 Predicted Maximum Velocities at SW 34"' Street Culvert for 2-year FloodEvent......................................................................................................3-8 Table3 Cost Summary................................................................................................3-9 Table 4 Alternative Summary Comparison................................................................ 3-12 Table 5 Alternative 1 Cost Estimate .......................................................End of Section 3 Table 6 AIternative 2 Cost Estimate .......................................................End of Section 3 Figures Figure 1 Project Area Map Figure 2 SW 30' Street — Existing Survey Figure 3 SW 34 h Street — Existing Profile and Utilities Figure 4 SW 341h Street — Alternative I - Plan Figure 5 SW 30 Street — Alternative 1 - Sections Figure 6 SW 34'h Street — Sanitary Sewer Relocation Figure 7 S W 340' Street — Alternative 2 - Plan Figure 8 SW 341h Street — Alternative 2 — Sections Figure 9 SW 341h Street — Alternative 2 — Temporary Diversion Plan Appendices Appendix A City As -Built Drawings, Existing Conditions Survey, and Site Photographs Appendix B Wetland Delineation and Stream Reconnaissance Technical Memorandum Appendix C Geotechnical Report Appendix D Springbrook Creek Flow Data ii Working Final Report.3oc 1 V22105 Table of Contents This report has been prepared for the use of the client for the specific purposes identified in the report. The conclusions, observations and recommendations contained herein attributed to R. W. Beck, Inc. (R. W. Beck) constitute the opinions of R. W. Beck. To the extent that statements, information, and opinions provided by the client or others have been used in the preparation of this report, R. W. Beck has relied upon the same to be accurate, and for which no assurances are intended and no representations or warranties are made. R. W. Beck makes no certification and gives no assurances except as explicitly set forth in this report. Copyright 2005, R. W. Beck, Inc. All rights reserved. Working Final Report. doc 11/21/05 iii e � _ n Y a rYss � f w' w F a - d ,�,�. s 33�•, Y it k -A, fk+ ;Yx � t �}A i rya y r - i Y � r Section 1 INTRODUCTION This report describes analysis and preliminary design performed as part of Phase 1 of the SW 34`h Street culvert replacement project. The report is divided into four sections. Section 1 presents project background, authorization and scope. Section 2 describes data collection and existing site conditions information. Design objectives and alternatives are described and compared in Section 3. Section 4 presents the recommended alternative in more detail and discusses environmental, utility service, and traffic considerations. Background The City of Renton's 1997 East Side Green River Watershed Plan and EIS (ESGRWP) (R. W. Beck, 1997) was an area wide planning level study that identified a number of projects that would help alleviate the flooding in the Renton Valley area, generally bounded by 1-405 to the north, Talbot Road S to the east, SW 43`a Street to the south, and the Renton City limits to the west. The ESGRWP identified the replacement of the SW 341h Street culvert crossing at Springbrook Creek as a necessary project to reduce upstream water levels and help alleviate flooding. The existing crossing consists of four 72-inch diameter corrugated metal culverts. The undersized culverts are a conveyance restriction during high flow events and the creek has overtopped the road. The conveyance restriction also causes water to backup upstream of the culverts, which contributes to upstream flooding problems (e.g., SW 43`d Street and Lind Avenue). The ESGRWP recommended that the culverts be replaced with two side -by -side 30-foot wide box culverts. The SW 34`h Street culvert and surrounding vicinity are shown on Figure 1. The Springbrook Creek drainage is described in detail in the ESGRWP. Springbrook Creek drains a 24 square mile watershed referred to as the East Side Green River Watershed (also known as the Black River Basin). Springbrook Creek drains to the Black River Pump Station (BRPS), where flows are pumped into the Green River. The BRPS is equipped with both upstream and downstream fish passage systems, however the fish resource is considered to be limited due to several factors including poor water quality, low dissolved oxygen levels, and lack of suitable spawning substrate, particularly in the low gradient reaches of the creek. Several flood protection improvements identified in the ESGRWP have already been completed, including the SW 27'h Street Culvert Replacement Project in 1999. The SW 34a' Street Culvert Replacement is the next highest priority project in the valley area. It will provide an important benefit to further reduce flooding in the Renton Valley. In addition to correcting the overtopping of the road, it will lower upstream water levels such that this improvement, working with other future planned projects, Working Final Reportdoc 11/21/05 Section 1 will provide the desired flood protection objectives in the valley area. One of the future planned projects is the SW 43'd Street pipe system improvement project. Authorization Engineering work for the project was authorized in contract CAG-05-045 between the City and R .W. Beck, Inc. on April 11, 2005. Scope The scope of the engineering agreement was divided into two phases. Phase I includes the following pre -design work for the SW 34`h Street Culvert Replacement project. ■ Site investigations —wetland delineation, surveying and mapping, and geotechnical ■ Identification and analysis of culvert replacement alternatives ■ Recommendation of preferred alternative ■ Report preparation and environmental permit preparation Phase 2 includes the final design of the SW 34`h Street Culvert Replacement Project. The City intends to move forward with the final design following review and approval of this pre -design report. Acknowledgements Stormwater utility supervisor, Ron Straka, F.E., oversees the City's stormwater program. The City of Renton project manager for this project is Allen Quynn, P.E. R. W. Beck, Inc. project staff included Mike Giseburt, F.E., project manager, and Lisa Gorry and Rick Lippold, P.E., project engineers. 1-2 R. W. Beck Working Final Repomdoe 11/21/05 Section 2 SITE INVESTIGATIONS AND CONDITIONS Section 2 SITE INVESTIGATIONS AND CONDITIONS Surveying and Mapping Surveying and mapping of the project area was performed by Duane Hartman and Associates. Their field survey work resulted in a two -foot contour map as presented in Figure 2. A full-sized map is included in Appendix A. Underground utilities were located and shown on the map. In addition to the horizontal locating of underground utilities, potholing was done to determine their depths. A number of utilities run along SW 34`h Street over the existing culverts. These include sewer (Renton), water (Renton), gas (PSE), buried electric (PSE), and communication (Qwest). Figure 3 presents a profile of the existing culvert and shows the depths of the existing utilities. It is important to note that on January 1, 1994, the City changed its elevation datum to NAVD 1988. The past hydrologic/hydraulic analysis conducted as a part of the ESGRWP as well as the previous roadway and utility design drawings were developed using NGVD 1929 datum. These datums are related as follows: NGVD 1929 datum + 3.58 feet = NAVD 1988 datum The held survey, figures contained in this report, and water elevations in this report are all referenced to the NAVD 1988 datum. Appendix A contains available City "As-builts" records of the existing culverts and City -owned utilities in the area as well as photographs of the site. Wetland Delineation and Stream Reconnaissance Jones & Stokes delineated wetlands 100 feet upstream and downstream of the SW 34`h Street culvert. A copy of the wetland delineation and stream reconnaissance technical memorandum is included in Appendix B (Jones and Stokes, 2005). Figure 2 shows the wetlands delineated in the vicinity of the SW 341h Street crossing and their associated 50-foot buffers. Wetland delineation methods were taken from the Corps' Wetland Delineation Manual (Environmental Laboratory 1987) and the 1997 Washington State Wetlands Identification and Delineation Manual (Washington Department of Ecology 1997). Both manuals require the presence of wetland indicators for vegetation, hydrology, and soils before an area is considered a wetland. Wetland habitat types are based on the U.S. Fish and Wildlife Service (USFWS) wetland classification system (Cowardin et al. 1979), which categorizes wetlands Working Final Report. doe 11121r05 Section 2 according to plant community types and hydrologic regime. This system is commonly used by local jurisdictions to help determine wetland functions and values. Wetlands ratings were based on Ecology's Washington State Wetlands Rating System — Western Washington (Ecology 2004) and the City of Renton's wetland classification system (Renton Code 4-3-050). Wetland 1 is a narrow riparian wetland that runs along both sides of Springbrook Creek upstream of SW 341h Street. Wetlands on both sides of a narrow stream (less than 50 feet) can be considered one unit, with the creek a characteristic of the wetland (Hruby 2004). In the project area, the wetland is dominated by palustrine emergent (PEM) habitat. Wetland hydrology is supported by high flows of Springbrook Creek and groundwater. Wetland 1 meets Ecology's definition of a Category III wetland and the City of Renton's definition of a Category 2 wetland because it is greater than 2,200 square feet and is not isolated (associated with Springbrook Creek). Wetland 1 is not severely disturbed (Category 3 wetland), and does not possess the high quality attributes of a Category 1 wetland. The City of Renton requires that Type 2 wetlands are given a 50-foot buffer. Wetland 2, similar to Wetland 1, is a narrow, riverine, flowthrough wetland that runs along both sides of Springbrook Creek downstream of SW 341' Street. Like Wetland 1, Wetland 2 is considered one unit. In the project area, the wetland is dominated by palustrine emergent (PEM) habitat. Wetland hydrology is supported by high flows of Springbrook Creek and groundwater. Wetland 2 meets Ecology's definition of a Category III wetland and the City of Renton's definition of a Category 2 wetland because it is greater than 2,200 square feet, is not isolated (associated with Springbrook Creek), is not severely disturbed (Category 3 wetland), and does not possess the high quality attributes of a Category 1 wetland. Type 2 wetlands in the City of Renton are given a SO -foot buffer. Regarding the stream, Washington State has designated Springbrook Creek a Shoreline of the State (WAC 173-18-210). As a Shoreline of the State, Renton classifies Springbrook Creek as a Class 1 stream with a standard buffer width of 100 feet. In the vicinity of SW 34"' Street, Springbrook Creek is a modified straight, trapezoidal, channel. Riparian vegetation is limited, dominated by reed canarygrass. Several small (one- to five -inch diameter) willows grow to the north of SW 34,' Street, between SW 341h Street and the outlet of the existing Springbrook Creek culverts. Stream gradient is low, and habitat is essentially one long glide. In places, reed canarygrass has invaded the active channel. Stream substrate is primarily a mixture of gravel and sand with some finer sediment. The existing culverts at SW 34`h Street are low gradient and do not appear to impair fish passage under normal flows. Salmon and trout are known to spawn upstream of the site. Kerwin & Nelson (2000) report chinook salmon, coho salmon, cutthroat trout, and steelhead trout all use Springbrook Creek and its tributary Mill Creek, located well upstream of SW 340' Street in the City of Kent. 2-2 R. W. Beck Working Final Report doc 1 if21/05 SITE INVESTIGATIONS AND CONDITIONS There is additional information about these wetlands included in the Wetland Delineation and Stream Reconnaissance Technical Memorandum by Jones and Stokes included in Appendix B. Information regarding environmental permits that will be required to replace the culvert and information regarding these permits is contained in Section 4. Geotechnical HWA GeoSciences, Inc. (HWA) performed geotechnical field investigations, laboratory testing, and engineering analysis to determine subsurface conditions at the Project site and to make recommendations regarding excavation, temporary shoring, foundation design, and dewatering for the Project. Subsurface investigations included two exploratory borings (designated BH-1 and BH-2, shown on Figure 2) to depths of 61.5 feet. The results of their work are summarized in a report dated October 14, 2005 that is included in Appendix C. The geotechnical investigations determined that the roadway is constructed on about 4.5 feet of roadway fill placed on top of a five-foot thick layer of organic material. Soils below the organic layer are generally interbedded silt and sand alluvium. As part of their investigations, HWA evaluated the foundation requirements for box culverts on spread footings and piles. Also, both three -sided box culvert (open bottom) and four-sided box culvert (full width slab bottom) construction were reviewed. Based on the site conditions, HWA recommends that a four-sided box culvert be placed on spread footings with a properly prepared subgrade. A pile foundation is not recommended because of poor pile capacity conditions. . Any organic or loose soils encountered during excavation will require removal and replacement with a suitable granular material for foundation preparation. Because the existing soils at the project location are susceptible to liquefaction, there is potential for settlement during a seismic event. By using a four-sided box, the bearing load is minimized and the potential for settlement is reduced. As part of the geotechnical analysis, field samples were taken of stream sediments to check for environmental contaminates such as hydrocarbons, volatile organic compounds, PCB's and heavy metals. The sampling and testing results indicate that the existing sediments do not exceed any dangerous waste criteria and do not require special disposal requirements. Traffic and Springbrook Creek Trail SW 34th Street is a 4-Iane asphalt concrete roadway with concrete curb and gutter and sidewalks on both sides. Total four -lane width is 44 feet. Total right-of-way width is 80 feet. Maintaining one lane of vehicular traffic along SW 341h Street through the construction zone will be considered in planning the project in order to maintain convenient access to the Iocal commercial businesses. This will either require phasing of construction, i.e., building only one-half of the culvert at a time and providing Working Final ReWrt.doc I U21/0s R. W. Beck 2-3 Section 2 traffic control, or building a temporary access road around the construction area (as was done for the SW 27th Street Culvert Replacement project). An option that should be considered during design is to close the road. The ability to close the road would result in reduced construction times and lower construction costs. This is further discussed in Section 4. The Springbrook Creek Trail is a paved recreational trail that runs in a north -south direction along the top of the creek's east bank. Construction activities may require temporary closure of the trail. Alternatively, it may be possible to detour the trail through the adjacent parking lots if agreement can be made with the property owners. 2-4 R. W. Beck Working Final Reporr.doc 11?21/05 Section 3 ALTERNATIVE ANALYSIS Section 3 ALTERNATIVE ANALYSIS Introduction As discussed previously, the ESCRWP recommended two side by side three -sided box culverts to replace the existing four 72-inch diameter CMP culverts. The preliminary design effort has considered additional options to provide a more complete analysis of construction alternatives that meet the project criteria. Additionally, a more detailed analysis has been done to incorporate information provided by the site survey, geotechnical explorations, and recommendations, and additional information provided by the City. This section identifies project objectives and design criteria, describes and compares two alternatives meeting these criteria, and identifies a recommended alternative. Project Objectives and Preliminary Design Criteria The primary objective of the Project is to increase the conveyance capacity through the SW 34 Street crossing at Springbrook Creek to eliminate roadway overtopping and to reduce upstream water levels during flood events. Through the development of the ESGRWP, a target criterion of allowing no more than 0.1 feet of headloss (water elevation rise) through the culverts for the future land use 100-year flow was used. This criterion was originally developed with input from the Natural Resources Conservation Service (NRCS) (formerly Soil Conservation Service). Other project goals include cost-effective construction, meeting environmental permit requirements, coordinating the Project construction with any future roadway improvements, and improving fish passage. The replacement culvert must also be designed to handle HS- 25 traffic loading. General criteria and issues considered when reviewing alternatives included: K Cost: Based on the Engineers construction cost estimate, a lower cost alternative is preferred. ■ Constructability: The following constructability issues were considered: Construction time: Typical `fish windows" allowed for construction within the creek are early July through September. Therefore, a method of construction which allows quick progress is preferred. Site constraints: The work area at the project site is limited. A type of construction that does not require a large laydown area is preferred. Working Final Report.doc 11121M Section 3 Dewatering: as discussed below, is it preferred to limit the amount of ground dewatering required? Traffic Impacts: The City desires the ability to have phased construction to keep at least one lane of traffic open. Although, as previously noted, it would be more cost effective construction if the road could temporarily be closed to traffic. Closing the road could result in cost savings on the order of $60,000 to $100,000. ■ Impact of construction on local business and area. ■ Utilities: As shown in Figure 3, numerous utilities cross above the existing culverts. Raising the top of the new culvert above the top of the existing culverts would require relocation of the existing utilities. Relocation of the privately owned utilities (gas, electric, and communications) would be paid for by their respective owners (PSE and Qwest) in accordance with franchise agreements. The relocation of the City's water and sewer lines would need to be paid for by the City. The option of not relocating these utilities is not possible because the construction of the replacement culvert below the location of these utilities would limit the height of the culvert and would not provide enough hydraulic cross section through the culvert to meet the project criteria. ■ Creek Diversion: Temporary diversion of creek flow, which will be required during construction and this temporary construction effort, needs to be considered when evaluating alternatives. A minimum diversion flow used for the SW 271, Street Culvert Replacement Project was I40 cfs, which considered historical flows during the time period of construction. ■ Control of Groundwater: Control of groundwater will be required during construction for constructability and to assure an adequate foundation. Wells and/or sumps will be required to draw the local water table below the earthwork elevation. An option which minimizes the depth of excavation is preferred. ■ Fish Passage: Alternatives that provide the largest open area, lowest stream flow velocities, natural bottom conditions, and open water surface are generally preferred. Bridges generally meet these criteria best. Because of its open bottom, a three -side Sox is generally preferred, aver a four-sided box by the Washington State Department of Fish and Wildlife (WDFW). If a four -side box is used, the bottom of the box must be set 20 percent, or about two -feet below the grade of the stream. ■ Foundation Type and Settlement Issues: The type of foundation is an important consideration in determining the preferred alternative. A foundation supported on piles provides a preferred open bottom and assures minimum settlement but is generally the most costly option. An open bottom three -sided box arrangement with wide spread footings to provide low soil bearing values is generally the lowest cost foundation but can require additional over excavation and backfill to provide a suitable footing subgrade. This option is also most susceptible to static and seismic settlement. 3-2 R. W. Beck Working Final ReNrt.doc l 1MIDS ALTERNATIVE ANALYSIS A closed bottom four-sided box arrangement provides a more forgiving structure regarding possible settlement issues as compared with the three -sided box with separate footings because of the wide continuous footing created by the bottom. However this option is more costly (compared to the three -sided box option). Descriptions of Alternatives The following two alternatives are discussed in detail and were chosen because they best meet the project criteria and construction issues. Both alternatives are precast concrete box type culverts. This type of construction best suits issues such as efficient hydraulics, quick construction, site constraints, cost, and durability. For the purpose of the discussion, closed bottom, four-sided box culverts are assumed. However, both alternatives also have the option of a three -sided box culvert. This is clarified further in the structural discussion below. Alternative 1— Double 30'X7' Box Culverts Alternative 1 is the recommended option described in the ESGRWP. A plan and sections of this alternative are shown on Figures 4 and 5. Alternative 1 includes the construction of two side by side 30-foot wide box culverts. For the purpose of this report, the replacement culverts were assumed to be 80 feet long across the full right- of-way width in order to allow for future modifications (widening) of the roadway. The replacement culverts would not need to extend the full 80-foot right-of-way if it is determined that no roadway or sidewalk widening will occur in the future, The soffit of the Alternative I culverts would be seven feet above the stream bed. This clearance would provide the necessary section to meet hydraulic criteria. At this height the culverts will be submerged during the design flow but would meet the 0.1- foot headloss criteria. The total box heights would be 8.5 feet to provide approximately three feet of foundation depth to provide for fish gravel above the footings and to have adequate depth for scour protection. Footings will be full width, continuous spread footings approximately 18 inches thick. The existing roadway will need to be raised approximately 1.7 feet to provide approximately three feet between the top of the culvert and the top of pavement. It is assumed that this arrangement will allow the water, gas, power, and possibly communications to be relocated but remain over the culverts. All utilities over the culvert would be encased in concrete or installed in a casing pipe (or as required by the utility) to provide extra protection at the low cover. So that the raised grade can be smoothly tied back into the existing vertical alignment, approximately 250 to 350 lineal feet of SW 30 Street would require reconstruction (depending on the length of required vertical curve, see discussion under roadway and sidewalk modifications in Section 4). New low points in the road would be created requiring installation of new catch basins at the low points. (See Figure 4). The existing eight -inch diameter sanitary sewer line crossing the existing culverts will require relocation so that it would flow east along SW 34th Street to Lind Avenue and tie into an existing sanitary sewer. This eight -inch diameter sanitary sewer provides Working Final Report.doc 11/21/05 R. W. Beck 3-3 Section 3 service to two properties on the east side of Springbrook Creek. The sanitary sewer currently extends west over the tops of the existing six-foot diameter CMP culverts. During the investigation, it was found that if the replacement culverts were to be designed so as to be below the existing eight -inch diameter sewer (to avoid relocation of the sewer), the height of the replacement culvert could only be about four feet and would not provide the desired hydraulic performance. Thus, it is necessary to relocate this sewer to the east. A possible alignment for the sewer relocation is shown on Figure 6. The relocation involves approximately 900 lineal feet of new sewer line, at depths up to about 11-feet. Additional information about the sewer relocation is included in Section 4. During construction, the temporary Springbrook Creek diversion could be accomplished by installing temporary cofferdams and piping that would route the creek through one of the existing CMP culverts while one box culvert is installed. The creek could then be routed through the new box culvert while the second box culvert was installed. In this way, no pumping and minimal temporary diversion piping would be required. Alternative 2 — Single 30'xl 0' Box Culvert This alternative includes construction of a single 30-foot wide by 10-foot high by 80- foot long box culvert. Sketches of this alternative are shown on Figures 7 and 8. A single culvert can be utilized because the extra height allows a free water surface through the culvert during the 100-year design flow and meets the headloss criteria. The actual culvert height would be 11.5-feet to provide below grade depth to the footing. Footings will be precast continuous full width spread footings approximately 18-inches thick. The 10-foot high culvert would require the road grade to be raised approximately 2.3-feet above the existing road. This assumes that the road pavement would be placed directly on the precast culvert top. The City's transportation department would need to determine the minimum thickness of asphalt over the top of the culvert that would maintain the integrity of the road surface. Tapering the raised road back into the existing roadway with vertical curves would require reconstruction of approximately 300 to 400 feet of SW 34t' Street (depending on the length of required vertical curve, see discussion under roadway and sidewalk modifications in Section 4). Reconstruction would include adjustment of driveways, manhole covers, curb and gutter, sidewalk, and landscaping. As with Alternative 1, new low points along SW 34t' Street would be created and require the installation of new catch basins. As for Alternative 1, the eight -inch diameter sanitary sewer line would be relocated and routed approximately 900-feet east to Lind Avenue. The water line can be routed under the culvert or be hung on the downstream face of the culvert in a carrier pipe. Figure 7 shows how the water line could be routed along the downstream face of the culvert. Based upon preliminary discussions with the City's water department, having the water line placed on the downstream face of the culvert is preferable to being placed under the culvert. This is further discussed in Section 4. 1t is assumed that the gas, electric, and communications lines will be routed under the culvert. 3-4 R. W. Beck Working Final Report doc 11/21/05 ALTERNATIVE ANALYSIS During construction a temporary pipeline would be required for Springbrook Creek diversion. Two 48-inch diameter pipes could be installed to route flow around the construction excavation. A schematic sketch of a potential diversion plan is shown on Figure 9. This approach was successfully employed on the SW 27th Street Culvert Replacement Project. Other Options This section discusses other options that were considered initially but not evaluated in detail as well as some variations of Alternatives 1 and 2 that could be considered. These options include: ■ Bridge: While bridges are often preferred for fish passage, this option was not considered as a part of this study or the original ESGRWP EIS. A bridge is not preferred for this project because (1) construction costs would be high, (2) it would be difficult to meet the City's design criteria of achieving a minimum two -foot clearance between the 100-year water surface and bottom low chord of the bridge requiring an excessive elevation rise in the road (approximately five to six feet), (3) there are difficult foundation conditions present at the site, {4) probable cast -in - place abutments would not meet the preferred criteria of fast construction; and (5) bridges require maintenance and inspections that may not be required for box culverts. ■ CMP: Replacement with a large CMP arch culvert (similar to the SW 43`d Street crossing). A large arch culvert would create too much headloss and not have adequate capacity. This was already considered in the ESGRWP. In terms of variations of Alternatives 1 and 2, one option that can be considered by the City is a double box culvert (Alternative 1) but with limited cover (e.g., placing the roadway pavement directly over the box culvert) so that the roadway would not require vertical adjustment. This would require utility relocates similar to that described for Alternative 2 but would have less construction impact on local businesses due to less roadway reconstruction required. Thus, it would also offer some cost savings and reduced construction time compared to Alternative 1. An order of magnitude cost comparison of this option was done and it was estimated that this could reduce the cost of Alternative 1 by as much as $100,000. However, after completing detailed cost estimates of Alternative 2 (as discussed later in this report), it was estimated that this option would still cost approximately $300,000 more than Alternative 2. While this option does have some advantages when compared to Alternative 1, it was considered much more costly than Alternative 2 and was therefore not evaluated in detail. Another variation of Alternative 1 could be a lower depth box culvert. Instead of two 30-foot wide by seven -foot high box culverts, the height could be reduced to six feet. This option was considered in an effort to not have to raise the existing roadway while still allowing utilities to be placed above the culvert (except the sewer). Again, this would have less construction impact on local businesses due to less roadway reconstruction required. The disadvantage of the reduced height is some additional Working Final Repan.doo l 1/21/05 R. W. Beck 3-5 Section 3 headloss that would increase the headloss through the culvert to above the desired 0.1 foot during the 100-year storm. For both Alternatives, the City also has the option of a three -sided open bottomed culvert or a four-sided closed bottom culvert. The four-sided culvert is more expensive but provides some additional measure of protection against possible settlement during an earthquake. With an estimated cost difference of $5,000 for Alternative 1 and $18,000 for Alternative 2, it is recommended that the City use the four-sided box culvert approach. Alternative Comparison The two alternatives were analyzed and compared based on the issues and design criteria discussed above. The following sections discuss design issues and alternative analysis. Hydraulics Hydraulic analysis of each alternative was performed using the FEQ model that was previously developed during the East Side Green River Watershed Project (ESGRWP) and since updated in the ESGRWP Technical Update Supplement —Draft (R. W. Beck, 2004). The analyses determined the relative performance of each alternative. The analysis simulations reflect the future land use condition, 100-year conveyance condition flow, and future conveyance system as recommended in the ESGRWP. The future conveyance system was used as opposed to the existing conveyance system to ensure that when all valley improvements are fully implemented these improvements will work together to meet the flood protection goals and target water surface elevations identified in the ESGRWP. The key future improvements include both downstream and upstream improvements including: ■ Removal of the Private Bridge north of SW 271h Street w SW 39 h Street to SW 43`d Street Pipe System Improvements ■ Renton Wetland Mitigation Project ■ Oakesdale (SW 41" Street) Culvert Replacement As part of the ESGRWP, two types of potential flood events were analyzed: a Storage Scenario, which includes events that produce very high water surface elevation at the BRPS due to pumping restrictions, and a Conveyance Scenario, which includes events that exhibit maximum xeak flows into the pump station forebay (severe local flood event). At the SW 34 Street culvert, the water surface elevations for the 100-year storage scenario are actually higher than the conveyance scenario. However, the conveyance event is the critical event for consideration of the culvert replacement because of significantly higher flows. For this reason the comparison focused just on the 100-year conveyance event. The results of the model simulations are presented in Table 1. For comparison purposes, this table also provides the results for the existing Springbrook Creek 3-6 R. W. Beck Working Final Report.doc l 1121/05 ALTERNATIVE ANALYSIS conveyance system (including the four 72-inch diameter culverts at SW 34`h Street and without the other improvements listed above). These results are taken from the ESGRWP Technical Update Supplement. Table 1 Hydraulic Performance of Existing SW 34th Street Culvert and Culvert Replacement Alternatives At SW 34', Street(2) 100-yr Change in Future Downstream upstream W.S. El. Alternative(') Flow W.S. EI, W.S. El. (Headloss)(ft.) (cfs) Existing Conveyance - Future 1269 17.30 19.1 1.7 Flow (conveyance event) Existing Conveyance - Future 848 17.70 17.6 0.1 Flow (storage event) Alternative 1 (Conveyance Event) 1219 17.07 17.16 0.09 Two 30' x 7' Box Culverts Alternative 2 (Conveyance Event) 1221 17.07 17.13 0.06 One 30' x 10' Box Culvert (1) Note the clear open area is specified. The actual height would be increased by approximately 1.5 to 2 feet to allow a natural bottom for fish passage. (2) Elevation Datum: NAVD BB. Both alternatives meet the performance criteria of a maximum headloss of 0.1 feet through the culvert. It is also noted that Alternative 1, while having a much larger cross section area than Alternative 2, results in greater headloss. This is because the tops of the Alternative 1 culverts are lower than the 100-year water level, resulting in additional hydraulic Iosses. For Alternative 2, the soffit of the culvert is approximately 0.8 feet above the simulated conveyance scenario 100-year water level. It would be 0.4 feet above the storage scenario 100-year event. In addition to considering the 100-year future condition flow for flood control, additional analysis was conducted to assess stream velocities through the culvert to meet fish passage requirements. The replacement culvert must be sized based on criteria set forth by the Washington Department of Fish and Wildlife (WDFW) for fish passage culverts. This was done by checking the stream velocities through the culvert for the 2-year event. The WDFW typically requires the consideration of the 10 percent exceedance flow (i.e., the flow rate which is exceeded only 10% of the time) for current land use conditions. However, the 2-year event was used for the analysis. This is conservative. On other stream systems, the 10% exceedance flow is typically 35 to 45% of the 2- year flow. Although WDFW typically considers flow rates for current land use Working Final Report. doc MUM R. W. Beck 3-7 Section 3 conditions in the basin, velocities were also checked for future land use conditions. The results are presented in Table 2. Table 2 Predicted Maximum Velocities at SW 34th Street Culvert for 2-year Flood Event Existinc Land Use Conditions Future Land Use Conditions Alternative Peak Water Peak Peak Water Peak Flow3 Surface Velocity Flow3 Surface Velocity (cfs) Elevation2 f s (cfs) Elevation f s Existing Culvert 318 13.9 2.8 561 15.7 5.0 4 — 72" culverts Alternative 1 318 13.7 0.9 561 14.9 1.4 Two 30' x 7' Box Culverts(') Alternative 2 318 13.7 1.9 561 %9 2.7 One 30' x 10' Box CulverP) (1 ) Note the dear open area is specified. The actual height would be increased by approximately 1,5 to 2 feet to allow a natural bottom for fish passage. (2) Elevation Datum: NAVD 88. (3) Source. FEQ modeling Results from Eastside Green River Watershed Plan Supplement, R.W. Beck, 2004. Draft. The results show that both culvert replacement options reduce flow velocities to allow fish passage. Typical maximum velocities for culverts 80 feet in length are 4 to 5 fps for adult fish species. The results also show that while the criteria typically used to compare these velocities is bases on current land use conditions flows, the result show that velocities for both alternatives would be acceptable event under future, fully built - out land use conditions in the basin. It is also noted that the culvert replacement will meet minimum depth requirements for passage. Low flow water levels for the existing culvert are typically 2 feet or more. During a site inspection on July 7, 2005, the water depth measured in the culvert was 2.7 feet. The replacement culvert will match the existing invert elevation so that summer flow depths will be in this range. Structural Structurally, both alternatives are similar. Both would use precast concrete box culverts. These structures are built with the top and sides as one unit. The footings could be cast -in -place or precast, however for construction efficiency in the field, precast is preferred. For Alternative 2, the culvert wall height at 11.5-feet is more than standard box culvert forms allow. Therefore a short 1.5-foot stem wall would need to be cast into the footing. The culverts will be designed for AASHTD HS-25 load criteria, or as requested by the City. Culvert loads include HS-25 vehicle live loads, vertical dead loads including 3-8 R. W. Beck Working Final K"rt.doa 11121/05 ALTERNATIVE ANALYSIS soil, pavement, and sidewalk, and lateral soil loads on the culvert walls. As recommended by the geotechnical report, the footings will be sized for a maximum bearing load of 2,000 psf. Pedestrian guardrail will be installed at the top edge of the culverts for fall prevention. Pedestrian guardrail will be designed for standard International Building Code (IBC) loads. It will not be designed for vehicle loads. The City can determine if vehicle guardrail protection is required. The geotechnical recommendation is that the box culverts be placed on spread footings. The subgrade for the footings should be prepared by over excavating two -feet and backfilling with crushed rock fill or CDF. The geotechnical investigation also found liquefiable layers of soil ranging from a total of six -feet thick to 24-feet thick. In a seismic event liquefaction of these layers could cause settlement of the box culverts and road fill. Settlement is estimated to range from one inch to 10 inches due to the variable total thickness of liquefiable soils. Frequently structures over liquefiable soils are placed on piles to prevent structural damage due to settlement, however, the geotechnical investigations found poor soil conditions for piles and concluded that piles would not be cost effective. As discussed in Section 2, a box culvert with a continuous full width bottom is recommended with consideration to possible settlement. While a full width bottom does not necessarily reduce static bearing loads, it provides a larger bearing area for redistribution of bearing loads if settlement does occur under the footings. It also structurally connects the base of box culvert walls, keeping them at equal distance minimizing potential stresses in the box culvert due to differential settlement. Considering structural aspects of the project, Alternative 2 is preferred because one box culvert is preferred over two box culverts minimizing potential future problems and inspections. Cost Preliminary cost estimates were developed for each alternative. These estimates include a 20 percent contingency, and 25 percent for design, administration, and construction engineering. Table 3 summarizes the overall construction costs for each alternative. The detailed cost estimates are included in Tables 5 and 6 presented at the end of this section. Table 3 Cost Summary Alternative Description Cost 1 Double 30'x7' 4-sided box culverts $1,770,000 2 Single 30'x10' 4-sided box culvert $1,385,000 Based on these cost estimates, Alternative 2, the single box, is significantly less expensive than Alternative 1. Working Final Report.doc 1121/05 R. W. Beck 3-9 Section 3 Construction Impacts Both the alternatives will involve the disruption of traffic on SW 34`, Street, disruption of utilities and storm drainage, and disruption of the adjacent Springbrook Trail. Nearby businesses will be impacted by traffic control required for the construction, construction noise, and temporary disruption of driveway access during road reconstruction. The current design approach is to keep SW 341h Street open with a minimum of one lane of traffic. Temporary traffic control, probably an automated signal, would control traffic to allow one direction to go at a time 24 hours a day. As previously noted a desirable option would be to close the road. The Springbrook Trail will need to be closed through the work area. It may be possible to detour the trail through the adjacent business parking lots. With respect to construction impacts, even though Alternative 2 disrupts more of SW 34th Street than Alternative l; it is preferred because of a shorter construction time. Utilities Relocation of the utilities will require coordination with PSE for gas and electric, Qwest for communication lines, and the City for water and sewer. Both alternatives require relocation of all the utilities, however Alternative 1 provides adequate cover over the culverts (three -feet) to place the utilities over the culvert. For Alternative 2, it is assumed that gas, electric, and communications will be relocated below the new culvert. The final utility configuration will need to be determined by the utility companies and it is possible that communications and power may need to be relocated under the culverts prior to construction of either alternative. For the water line, the City water department has indicated that temporary bypass lines will be necessary while the culverts are being installed. This may also be necessary for the gas. Multiple temporary relocations may be required due to construction phasing. Alternative 1 is preferred regarding utility construction due to the greater depth of cover over the box culvert. Control of Water An important consideration during construction will be the control of water. This includes both the diversion of the creek, dewatering of the groundwater and storm water collection and treatment in the disturbed construction area. The flow in the creek during the summer construction season is normally in the three to four cfs range, but can increase to greater than 40 cfs if there is a summer rainstorm. Appendix D contains a summary of daily flows in Springbrook Creek for the period October 1993 through January 1997. The creek diversion will require both upstream and downstream cofferdams with a means to carry the creek flows through or around the site. For planning purposes two diversion schemes were considered, one for the two box alternatives, and one for the one box alternative. 3-10 R. W. Beck Working Final RVort.doc 11/21/05 ALTERNATIVE ANALYSIS For the two -box Alternative 1, it is assumed that the creek can be diverted through one of the existing CMP culverts while one of the box culverts in installed. Once the initial box culvert is complete, the creek can be routed through that box culvert while the second box culvert is installed. For the single box culvert alternative, the culvert will be located centered over the existing CMP culverts and therefore using the existing culverts for diversion is not an option. Creek diversion will need to bypass the culvert installation area. While the final diversion option will be up to the contractor, it is assumed that two 48-inch diameter culverts would be used to divert the creek. This approach was successfully used for the SW 27th Street Culvert Replacement. Cofferdams will be placed upstream and downstream of the work area. For both alternatives, groundwater dewatering will be required for construction of the culvert foundations. The geotechnical report recommends lowering the groundwater to three feet below the maximum excavation depth. Therefore, groundwater draw down will likely be on the order of nine feet. Dewatering will require the use of dewatering wells or well points to achieve this level of water table draw down. The final dewatering design will be required to be contractor designed. Since water table draw down can create settlement, nearby facilities such as manholes will need to be monitored for movement. If such movement is detected, ground water re -injection may be required to prevent water table drawdown away from the immediate construction site. With respect to the control of water, there is not a considerable advantage between alternatives. Alternative 2 requires the need for constructing a separate bypass, but Alternative 1 has a Iarger construction footprint and therefore requires dewatering over a larger area and its associated risk of settlement. Environmental impacts The primary adverse environmental impact of the project will be temporary and related to construction. In order to minimize the impact, the work in the creek will have to be performed during the fish construction window that runs through the months of June, July, August, and September. Precise dates will need to be determined by Washington State Department of Fish and Wildlife. Since this coincides with the low water levels in the stream, it does not adversely affect the construction schedule or cost. During construction, any water collected within the work area will need to be treated before being released into Springbrook Creek in accordance with the City's drainage requirements. Treatment can consist of settlement ponds, or water treatment tanks (such as a Baker Tank). However, due to the significant amount of dewatering and lack of work area, use of Baker Tanks is likely desirable. During installation of temporary diversions and cofferdams, the Contractor will be required to trap any fish behind cofferdams and release them back into the creek, The installation of the cofferdams will result in a temporary impact to wetland vegetation. Working Final ReportAm 11/21/05 R. W. Beck 3-11 Section 3 Long term, the construction of the new culvert will provide a more natural and better lighted streambed (as compared with the existing culverts) to enhance fish passage. In addition, the new substrate of spawning gravels within the culvert could be used by fish. The added hydraulic capacity will also reduce flooding potential upstream of the culvert. With respect to environmental impacts, neither alternative has a considerable advantage. Recommended Alternative Listed below are some of the major advantages and disadvantages of each alternative. Table 4 Alternative Summary Comparison Advantages Disadvantages Alternative 1 Minimizes how much road is Highest cost Double 30'x 7' box culverts required to be raised. Creates very wide creek at crossing for Allows utilities to be run over top of greater wetland impact culvert Submerged hydraulic condition at design flow Longer construction duration Alternative 2 Lowest cost Minimum cover over culvert requires Single 30'x 10' Water surface is below soffit of utilities to be relocated under culvert box culvert culvert at design flow, lowest head Higher raised road creates more of 341h loss Street reconstruction Less structure for less future maintenance Shorter construction duration Higher internal clearance for any future maintenance Based on the analysis of the alternatives, the preferred arrangement is Alternative 2, the single 30-foot-wide by 10-foot-high four-sided box culvert. 3-12 R. W. Beck Working Final Reporl.doc 11/21/05 TABLE 5 COST ESTIMATE - ALTERNATIVE 1 Item General and initial construction traffic control and safety temp ESC relocate SS approx 900' east, including manholes SD structure with SS pipe penetration ground water dewatering Qwest relocate communication duct PSE relocate power and gas Install Diversion upstream and downstream cofferdams Phase 1 (southwest construction) Sheet pile wall at CL SW 34th pavement and sidewalk demo (for phases 1 thru 4) temporary relocate 12" water excavate for box culvert and SW retaining wall haul excavation extra cost for CMP removal subgrade fabric reinforcement subgrade crushed rock backfill procure & deliver 40 LF, 30'x 6' 4 sided box culv install box culvert southwest wing wall backfill phase 1, imported streambed gravels and improvements Phase 2 (northwest construction) pull and relocate sheet pile shoring temporary relocate 12" water line excavate for box culvert haul excavation extra cost for CMP removal subgrade fabric reinforcement subgrade crushed rock backfill procure & deliver 40 LF, 30'x 6' 4 sided box install box culvert northwest wing wall backfill phase 2, imported streambed gravels and improvements Phase 3 (northeast construction) remove and reinstall cofferdams pull and reinstall sheet pile excavate for box culvert Quanti Units Unit Price Cost 1 LS $15,000 $15,000 1 LS $14,000 $14,000 900 LF $120 $108,000 1 EA $6,000 $6,000 1 LS $130,000 $130,000 $0 $0 1 LS $6,000 $6,000 910 SF $20 $18,200 900 SY $6 $5,400 1 LS $6,000 $6,000 2300 CY $10 $23,000 2300 CY $10 $23,000 1 LS $4,000 $4,000 200 SY $5 $1,000 150 CY $30 $4,500 40 LF $1,650 $66,000 1 LS $7,000 $7,000 600 SF $35 $21,000 1242 CY $15 $18,630 100 CY $30 $3,000 280 SF $20 $5,600 1 LS $5,000 $5,000 1960 CY $10 $19,600 1960 CY $10 $19,600 1 LS $4,000 $4,000 200 SY $5 $1,000 150 CY $30 $4,500 40 LF $1,650 $66,000 1 LS $5,000 $5,000 600 SF $35 $21,000 700 CY $15 $10,500 100 CY $30 $3,000 1 LS $6,000 $6,000 770 SF $20 $15,400 1540 CY $10 $15,400 haul excavation 1540 CY $10 $15,400 extra cost for CMP removal 1 LS $1,000 $1,000 subgrade fabric reinforcement 200 SY $5 $1,000 subgrade crushed rock backfill 150 CY $30 $4,500 procure & deliver 40 LF, 30'x 6' 4 sided box 40 LF $1,650 $66,000 install box culvert 1 LS $5,000 $5,000 northeast wing wall 600 SF $35 $21,000 backfill phase 3, imported 830 CY $15 $12,450 streambed gravels and improvements 100 CY $30 $3,000 Phase 4 (southeast construction) relocate traffic to north side 1 LS $2,000 $2,000 permanent relocate 12" water line 1 LS $8,000 $8,000 pull and reinstall sheet pile 280 SF $20 $5,600 excavate for box culvert 1750 CY $10 $17,500 haul excavation 1750 CY $10 $17,500 extra cost for CMP removal 1 LS $1,000 $1,000 subgrade fabric reinforcement 200 SY $5 $1,000 subgrade crushed rock backfill 150 CY $30 $4,500 procure & deliver 40 LF, 30'x 6' 4 sided box 40 LF $1,650 $66,000 install box culvert 1 LS $5,000 $5,000 southeast wing wall 600 SF $35 $21,000 backfill phase 4, imported 800 CY $15 $12,000 streambed gravels and improvements 100 CY $30 $3,000 Road and Utilities CIP concrete closure between boxes 6 CY $600 $3,600 CIP parapet on boxes 20 CY $400 $8,000 demolish remainder of pavement and sidewalk 1300 SY $6 $7,800 final grading 2000 SY $1 $2,000 crushed surfacing 300 CY $30 $9,000 curb and gutter 540 LF $15 $8,100 12" storm drain at new road low points 100 LF $50 $5,000 catch basins for storm drain 4 EA $1,000 $4,000 existing 60" and 36" storm line modifications 1 LS $4,000 $4,000 HMA pavement 1400 SY $10 $14,000 sidewalks 2500 SF $3 $7,500 mist utility work 1 LS $5,000 $5,000 topsoil and landscaping 1 LS $5,000 $5,000 pedestrian guardrail 340 LF $50 $17,000 Subtotal $1,074,780 Mobilization, 10% $107,478 Subtotal $1,182,258 Contigency, 20% 236 452 Total Construction Cost $1,418,710 Engineering and Construction Management, 25% $354,677 Total Construction plus Engineering $1,773,387 TABLE 6 COST ESTIMATE - ALTERNATIVE 2 Item General and initial construction traffic control and safety temp ESC relocate SS approx 900' east SD structure with SS pipe penetration Groundwater dewatering Quest relocate communication duct PSE relocate power Install Diversion initial pavement and sidewalk demo trench excavation excavation haul install 2 - 48" HDPE pipes backfill north half, using excavated material crushed surfacing for detour lane upstream and downstream cofferdams Phase 1 (south half construction) temporary relocate 12" water line sheet pile wall shoring excavate for box culvert haul excavation extra cost for CMP removal subgrade fabric reinforcement subgrade crushed rock backfill procure & deliver 40 LF, 30'x10' 4 sided box cult' install box culvert South wing walls streambed gravels and improvements backfill phase 1, imported Phase 2 (north half construction) modify sheet pile shoring temporary relocate 12" water line excavate for box culvert haul excavation extra cost for CMP removal subgrade fabric reinforcement subgrade crushed rock backfill procure & deliver 40 LF, 30'x10' 4 sided box install box culvert north wing walls 60"06" storm drain modifications streambed gravels and improvements remove cofferdams Quanti Units Unit Price Cost 1 LS $10,000 $10,000 1 LS $12,000 $12,000 900 LF $120 $108,000 1 EA $6,000 $6,000 1 LS $110,000 $110,000 700 SY $6 $4,200 1550 CY $10 $15,500 800 CY $10 $8,000 400 LF $68 $27,200 750 CY $5 $3,750 30 CY $30 $900 1 LS $6,000 $6,000 1 LS $6,000 $6,000 840 SF $20 $16,800 1600 CY $10 $16,000 1600 CY $10 $16,000 1 LS $4,000 $4,000 200 SY $5 $1,000 150 CY $30 $4,500 40 LF $1,900 $76,000 1 LS $7,000 $7,000 900 SF $35 $31,500 120 CY $30 $3,600 1500 CY $15 $22,500 200 SF $30 $6,000 1 LS $5,000 $5,000 1600 CY $10 $16,000 1600 CY $10 $16,000 1 LS $4,000 $4,000 200 SY $5 $1,000 150 CY $30 $4,500 40 LF $1,900 $76,000 1 LS $5,000 $5,000 900 SF $35 $31,500 1 LS $3,000 $3,000 120 CY $30 $3,600 1 LS $2,000 $2,000 remove north half diversion piping 1 LF $2,000 $2,000 backfill phase 2, imported 1100 CY $15 $16,500 remove remainder of shoring 1 LS $3,000 $3,000 relocate traffic to far north lane 1 LS $1,000 $1,000 excavate and remove diversion pipes, south half 340 CY $15 $5,100 backfill diversion pipe excavation 340 CY $15 $5,100 Raise Road and Install Utilities demolish remainder of pavement and sidewalk 1200 SY $6 $7,200 CIP parapet wall on boxes 4 CY $400 $1,600 fill to subgrade 700 CY $15 $10,500 install permanent 12" water line 1 LS $10,000 $10,000 final grading 2800 SY $1 $2,800 curb and gutter 700 LF $15 $10,500 crushed surfacing 400 CY $30 $12,000 12" storm drain at new road low points 100 LF $50 $5,000 catch basins for storm 4 EA $1,000 $4,000 existing 60" and 36" storm drain modifications 1 LS $4,000 $4,000 HMA pavement 1800 SY $10 $18,000 sidewalks 3000 SF $3 $9,000 pedestrian guardrail 220 LF $50 $11,000 raise utility MH covers, misc 1 LS $5,000 $5,000 topsoil and landscaping 1 LS $6,000 $6,000 Subtotal $839,350 Mobilization, 10% $83,935 Subtotal $923,285 Contigency, 20% $184,657 Total Construction Cost $1,107,942 Engineering and Construction Management, 25% $276,986 Total Construction plus Engineering $1,384,928 Section 4 RECOMMENDED ALTERNATIVE Section 4 RECOMMENDED ALTERNATIVE Introduction As discussed in Section 3, Alternative 2, a single 30-foot wide by 10-foot high four-sided precast concrete box culvert is the recommended alternative. The following paragraphs reiterate the description of the recommended alternative and provide additional details regarding the implementation of the recommended alternative. Traffic and Springbrook Creek Trail For the purpose of this study it is assumed that a single lane of SW 34th Street must be kept open during construction. This will require continuous traffic control. An automated traffic signal will be required to be installed so traffic can be controlled 24 hours a day. During working hours, it is likely flaggers will be required because of the close proximity of the traffic lane to the construction. The single detour lane will need to change locations based on the construction sequencing determined by the contractor, To maintain the traffic two options could be considered. The first is to maintain one lane of traffic within the road right-of-way. This would require the construction to be phased. This approach would include installing the south half of the culvert initially with traffic detouring to a single lane on the north side. The south half would then be backfilled and traffic detoured to the south side and the north half then constructed. The second option would be to build a temporary bypass road around the construction area and outside the right-of-way. This was done for the SW 27`h Street Culvert Replacement Project. In this way, the culvert could be installed in one phase. Because there is adjacent development at SW 34th Street, it is uncertain whether there is adequate space for this option. It may also require the use and approvals of the adjacent property owners. There will likely need to be brief total road closures during working hours for certain construction activities such as installation of creek diversion piping or installation of sheet piles down the center of the road (required for phased construction and keeping the roadway open). Driveway entrances to adjacent businesses will need to be briefly closed during some construction activities such as sanitary sewer installation and road/sidewalk demolition and reconstruction. Working Final Report.doc 1 U21105 Section 4 During construction the recreation trail on the east bank of the creek will be required to be closed through the construction area. There may be an opportunity to detour foot and bicycle traffic through the adjacent business parking areas. Prior to construction, the Contractor will be required to prepare a traffic control plan that is approved by the City's Transportation Department. While keeping a single lane of traffic open during construction is desirable for local businesses and fire protection, doing so would take up space at an already tight construction area and add cost and construction time (approximately two to three weeks) to the project. It is recommended that the City investigate the possibility of closing the road during construction. The investigation should include talking to local businesses about road closure and impacts to traffic and pedestrian use, as well a discussion with the fire marshal regarding emergency access. The City should also determine if public transportation is affected. The City may consider the SW 34th Street culvert replacement project an opportunity to provide pedestrian safety improvements to the Springbrook Creek Trail crossing. Improvements could include signage or painting of a pedestrian crosswalk. Dewatering/Diverting Springbrook Creek Groundwater dewatering will be required during construction because of the high water table throughout the project area. The underlying soils are fairly pervious, therefore it is assumed that the groundwater elevation is approximately equal to the creek water surface elevation. In order to provide appropriate working conditions for foundation preparation, the geotechnical report recommends dewatering three -feet below the maximum depth of earthwork. It is likely that the groundwater will require approximately a nine -foot draw down at the construction site. This will necessitate dewatering wells and pumps. The dewatering system will be contractor designed based on soils information provided in the geotechnical report. Since water table draw down can create settlement, it is recommended that Contractor be required to set up a plan to monitor for settlement. During construction of the proposed culvert, Springbrook Creek will require temporary diversion past the installation. Figure 9 shows a schematic of how the temporary diversion could be designed. It is anticipated that the plan will include earth embankment cofferdams with impervious linings and two 48-inch diversion pipes. This concept is based on the method employed by the contractor during the replacement of the culvert crossing SW 27th Street. For the SW 27th Street Culvert Replacement Project, the Contractor designed a system to pass 140 efs with one foot of freeboard. The required diversion capacity was based upon anticipated flows between a two-year and I0-year return period storm for the construction months. The diversion piping size for the SW 341h Street project could vary depending on actual upstream cofferdam height, but it is anticipated that two 48-inch pipes will be sufficient to divert the Creek during construction. A diversion consisting of temporary cofferdams and diversion pipes will be shown conceptually on the contract drawings. However, final design of the diversion will be contractor -designed. 4-2 R. W. Beck Working Final Report.doc 11/21/05 RECOMMENDED ALTERNATIVE Rights -of -Way and Easements Additional research during the design phase is necessary to determine the extent of property easement needs, King County Drainage District No. 1 owns a 40-foot wide strip of land for Springbrook Creek both north and south of the SW 34th Street right- of-way. Approval from the drainage district will be required. The 40-foot wide strip is within a 115-foot wide Springbrook Creek buffer easement area. Within this easement area, it is likely that no additional easement is required for the City to perform drainage improvements, however, this should be confirmed. Temporary construction easements may also be necessary for road restoration and tying the raised road back into private driveways. Utility Relocations The gas, power, water, sanitary sewer, and communication utilities currently routed over the existing culverts will have to be relocated to avoid conflict with the new culvert. It is anticipated at this time that the utilities wilI be relocated as follows: Sanitary Sewer — rerouted to extend east. The existing west running line will be terminated. Two options for relocating the sewer were considered. These options were evaluated using available as -built information provided by the City. One option included installing approximately 800 lineal feet of new 12-inch diameter sewer line at a minimal slope along the north side of SW 34'h Street and tying in to an existing sanitary side sewer located just west of Lind Avenue. This option was not preferred by the City because the low flows may not be adequate to cleanse the pipe and it was preferred to have the pipe in the right-of-way. The preferred option is to route a new 8-inch diameter sewer line along the center of SW 34'h Street and connect to an existing sewer in the southwest area of the intersection of SW 341h Street and Lind Avenue. A preliminary layout of this sewer line is shown on Figure 6. In order to tie into the existing sewer at this location, the new 8-inch sewer would be at minimum grade (0.4%) and would cross an existing 60-inch diameter storm drain at the same depth. One method that the City has used in the past to make a crossing like this is to add a new manhole to the existing storm drain line and have the sewer hard piped in ductile iron through the manhole. In this way, both pipelines can be at the same elevation but flows would be kept separate. For final design is it recommended that additional survey be done to get actual utility locations to assure that adequate drop is available, to check conflicts with other utilities along the proposed sanitary sewer alignment, and to consider options to avoid the need to have a crossing within a manhole. Water — based on pothole information acquired during this phase, the existing 12-inch water line runs just across the tops of the existing CMP culverts along the south side of the road. Rather than relocate the line under the culvert, the City's preference is to suspend the relocated water line along the downstream (north) face of the new box culvert. This requires extending the line from the south to the north side of the road and back again. The suspended portion of the water line would be protected within a larger (22-inch diameter) carrier pipe. Brackets bolted to the box culvert face and/or Working Final Repori.doc 11/21105 R. W. Beck 4-3 Section 4 parapet wall would support the pipe. Couplings at each end of the span will be installed to allow some movement between the suspended section and buried sections. Gas — It is assumed that the PSE gas line will be relocated under the new box culvert prior to construction of the box culvert. Another option would be to route the line over the culvert in the non -roadway section. The line could be encased or otherwise protected to compensate for the low cover. Electric Power — It is assumed that the buried PSE power lines will be relocated under the new box culvert prior to construction of the box culvert. Other options would be routing over the culvert in the non -roadway section. The lines could be encased or otherwise protected to compensate for the low cover. Communications - It is assumed that the Qwest buried communication lines will be relocated under the new box culvert. Note that PSE (power and gas) and Qwest (communication) are ultimately responsible for relocation of their utilities. Therefore other alternatives may be possible. The contractor will be required to coordinate with the utilities so that utility relocates can be accomplished during the construction, as required. Culvert Foundations The recommended foundation for Alternative 2 is a continuous full bottom spread footing. A pile foundation was also considered but determined unfeasible due to poor existing soil conditions. The spread footings can be precast units constructed by the precast manufacturer of the box culvert. Using precast footings speeds construction time considerably. As discussed in the geotechnical report, the underlying soils contain layers of liquifable material. This creates a risk that during a major earthquake event that settlements of the box culvert could occur. The report estimates that from one -inch and 10-inches of settlement are possible during a design (i.e., 1 in 475 years) seismic event. The overall depth of the liquifable material appears extremely variable, increasing the chance that differential settlements could occur. A local evenly distributed settlement would likely not damage the culvert structure but would result in a reduced hydraulic section. If serious differential settlements occurred it is possible that stresses due to this settlement could cause structural damage of the box culverts. Use of a continuous, full width bottom can minimize the potential amount of settlement as well as help prevent damaging stresses in the structure because the box culvert walls are structurally tied across the bottom. Excavation and placement of a crushed rock or controlled density fill mat for foundation support will mitigate the effects of liquefaction. Other methods of liquefaction mitigation are typically expensive and may not be suited to the site. The most certain approach to eliminate risk is to place the structure on piles. Because the poor soil conditions extend beyond the boring depths, the required depth of piles is unknown at this time. The piles would have to be designed to sustain the design load and potential downdrag forces and would therefore be very long and costly. To 4-4 R. W. Beck Working Final Report.doc 3 U2110 RECOMMENDED ALTERNATIVE ascertain the conditions of the deeper soils conditions an additional boring or another test such as an electronic Cone Penetration Test (CPT) down to 150 feet would be necessary (cost of about $9,000). Even if further deep exploration is done, it is highly likely that the required depth and/or size of piles to support the load and downdrag would make a pile system cost prohibitive. In summary, it is recommended that the culvert consist of a four-sided structure and that it foundation be prepared by the excavation and placement of a shallow layer of crushed rock or controlled density fill mat. The four-sided option, supported directly on a prepared pad, provides a reasonable level of risk for the type of facility under consideration. There may be some loss of serviceability (freeboard) or need for structural repairs in the event of the design earthquake occurrence; however, it is also possible that this could conceivably not happen during the design life of the facility. Road and Sidewalk Modifications The recommended alternative requires that the existing road grade be raised approximately 2.3 feet at the center of the culvert. Therefore, a revised vertical alignment is required for SSA' 341h Street in the immediate vicinity of the project. One approach to the vertical alignment modifications is shown on Figure S. This plan includes two 50-foot sag vertical curves and one 150-foot crest vertical curve. This approach would require demolition and reconstruction of approximately 300 feet of SW 341h Street and modifications to driveways, adjacent businesses, sidewalks, landscaping and some utility structures. The adjustment would create new low points along the road and require installation of new catch basins. It is noted however, that although the 50-foot vertical curves meet the design guidelines of AASHTO, they do not meet the City's minimum vertical curve length requirements and that moving forward using the two 50-foot sag vertical curves would require approval from the City's Administrator. The City Code specifies 200-foot vertical curves for all changes in vertical grade, although the City's Transportation Department reduces this to 150 feet on occasion. The City's Transportation Department prefers the longer length on arterials in order to improve appearance and provide a comfortable ride. If the vertical curves are required to be 150 feet the length of roadway reconstruction would increase. It is recommended that during design the optimum curve length be selected to balance minimizing the length of road construction (and associated costs) with the need to provide adequate length for appearance and comfort. Again, if the ultimate length is less than 150 feet, approval of the City Administrator is required. Environmental Considerations In general, the project will result in long-term environmental benefits. These benefits include improved fish passage and spawning habitat and a reduction in upstream flooding and associated water quality impacts. There will be no permanent loss of wetland area. Approximately 1,100 square feet of Wetland 1 and associated stream and 1,650 square feet of Wetland 2 and associated stream will be temporarily Workiag Final Repon doc 11/22/05 R. W. Beck 4-5 Section 4 disturbed during construction through the temporary creek diversion and/or excavation activities. This impact is expected to be temporary and impacted areas will be re - vegetated. Environmental impacts during construction are mostly related to the potential for erosion and an increase in turbidity in Springbrook Creek. These impacts will be mitigated by diverting clean water around the construction activities, treating dewatering water, limiting the time of construction, implementing erosion control best management practices, and re -vegetating disturbed areas. During development of this pre -design study, a meeting was held at the site with the local WDFW habitat manager. Through discussions about the project and impacts, it was suggested that some habitat improvements, in the form of adding rootwads, be included as part of the project. To minimize disturbed area and dewatering costs, the extent of rootwad placement would be limited to the dewatered area between the temporary cofferdams. Figure 7 presents a concept for the rootwad placement. The plan includes widening of the west side of the channel and placement of two logs with root wads on the west bank both upstream and downstream of the crossing. The logs are crossed to increase the complexity of the microhabitats provided and are placed at the edge of the existing channel. Although not shown on this figure, the mitigation plan will also include plantings to shade the alcoves where the logs will be placed. Potential for Scour or Sediment Deposition There is a low potential for scour due to the flat gradient and low channel velocities and full -width bottom through the culverts. Nevertheless, the culvert bottom will be placed three -feet or more below the stream bed to provide the required depth of streambed gravels and minimize potential scour. Gast -in -place cut-off walls may also be constructed at the culvert entrance and exit. Sediment deposition is ongoing along the Springbrook Creek system and over time sediment build-up will continue to occur throughout the system. In the past, sediment build-up has occurred in the Iower reaches of the creek closer to the Black River Pump Station and in the vicinity of Grady Way. Sediment deposition in and around the SW 341h Street culvert is expected to be about the same as that within the adjacent channels. Sediment will tend to build up and then be washed downstream during larger events. Potential for Contaminated Sediments Although there is potential for encountering contaminated sediments during the excavation for the culvert replacement, sampling along Springbrook Creek done as a part of the geotechnical investigations found no contaminate levels above required standards. Therefore additional sediment sampling is not planned during the design phase or during construction. 4-6 R. W. Beck Working Final Report.doe 1 1Ilzro5 RECOMMENDED ALTERNATIVE Permits and Regulatory Issues The following permits have been identified: ■ Sensitive Area Ordinance compliance from City of Renton ■ JARPA permit which combines the Hydraulic Project Approval (HPA) from Washington State Department of Fish and Wildlife ■ Temporary Water Quality Modification Permit from Washington State Department of Ecology ■ COE 404 permit for working in the Wetland ■ Shoreline Master Use Permit The Corps administers Section 404 of the Clean Water Act, which regulates the discharge of dredged or fill materials into Waters of the United States, including wetlands. For projects requiring Section 404 Permits, the Corps makes the final determination as to whether the area meets the definition of a jurisdictional wetland. Section 401 of the Clean Water Act requires applicants for Section 404 permits to obtain 401 water quality certification from the appropriate certifying agency. In Washington, that agency is the Ecology. Section 401 certification ensures that projects discharging to Waters of the United States, including wetlands, fall within specific water quality standards. Conditions of the 401 Certification become conditions of the Corps 404 Permit. Project information should be submitted to Ecology for approval. Applicable City of Renton regulations Regulations: Chapter 3 (Environmental Development Standards). include RMC Title IV - Development Regulations) and Chapter 4 (Property Section 404 and 401 Permits require the submittal of a Joint Aquatic Resources Permit Application (JARPA) to the above -mentioned agencies for approval before initiating any activities within the wetland identified on -site. Depending on the proposed activity that occurs in the wetland, a wetland report and wetland mitigation plan are typically requested by the Corps, Ecology, and the local jurisdiction, as part of the JARPA submittal. Schedule Following approval of this design report, required permit applications can be developed and submitted. The most lengthy permit to obtain is typically the Corps 404 permit, which can take anywhere from 6 months to 18 months. Therefore, it is most likely that construction will take place in 2007. As noted previously, construction within the ordinary high water will need to be accomplished during the months of June through September (and possibly mid - October). One item to consider regarding the schedule is the lead-time necessary for ordering the precast concrete sections. A lead-time on the order of two to three months may be required. Assuming a target start date for construction of July 2007, Working Final Report.doc 11122/05 R. W. Beck 4-7 Section 4 the City should attempt to award the contract on or before April 1, 2007 or have a separate procurement contract for the precast box culvert sections. 4-8 R. W. Beek Working Final Report. doe 11/22/05 Section 5 REFERENCES Section 5 REFERENCES Kerwin, John and Nelson, Tom S. (Eds.). December 2000. "Habitat Limiting Factors and Reconnaissance Assessment Report, Green/Duwamish and Central Puget Sound Watersheds (WRIA 9 and Vashon Island)." Washington Conservation Commission and the King County Department of Natural Resources. HWA Geosciences Inc. 2005. SW 30 Street/Springbook Creek Culvert Improvement Project. October 14, Hruby, T. 2004. Washington State wetland rating system for western Washington — Revised. Washington State Department of Ecology Publication #04-06-025. Jones & Stokes. 2005. 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaisssance Tecl-incial Memornadum. May 24`h. (J&S 05287.05) Renton, WA. R.W. Beck, Inc. I997. East Side Green River Watershed Plan, Prepared for the City of Renton. Washington Department of Ecology. 1997. Washington state wetlands identification and delineation manual. (Publication No. 96 94.) March. Olympia, WA. Working FinalReport.doc 11/21/05 FIGURES W rn a a- CL I R I ' I SW 2M St r I I3 Cn e Y a� G I I 11t SW 34th St 1 I I I I PLAN SCALE: 1'400' CITY OF RENTON a�Yuw rws-W'&-W-VWb o w-x+ D"t NOTE: THE PROJECT AREA LAND USE IS DESIGNATED EIAPLMUENt AREA — VALLEY. N 2DO O 200 4OO 1'=20D'-0 Soak Feet SW 34TH STREET to s�-0s CULVERT IMPROVEMENT PROJECT FICU RE 1 PROJECT AREA MAP col) CL CL IL MIND r MISS Cr N CMMM INIoo RN IN CM NlK �OF NUMEM 5M N weI 'W 9, one FIRIM "Al it c 0061:10 SIT Pt 4 FIM Of lftX C MR QXM CONCRIDE OPIRM 1 it Istoldfisa 141MUNLOM REAM i1= FEEF SIX 97 co M I E W 910 Wis WHOM w Im BH-2 ecff EL lfin —i 50* WETLAND RNFER 50' WETLAND BUFFER me w It, I WEnA4D 1 Iftl 11 v IIA E WE 11.113 IL 12M 110011:1 21I7 M i I wr itz ilM FIN ON WETLAND 2 R p 7 4E-12A_ 79' CUP vrnpu r1i I vERr IE=7.58 1E B.09 I 72)AP -CMP STORM CULVERTsp-a lL ISM RAFAM Ulm FM SPRJNCBRDDK CREEK i1 SPRINGBROOK (;PEE]< lum MIME im RE 1E 8,12 =72-rlip RID JW 21L PA ON 04)W/7GM —a -cw. 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Hu mm 0r354r W SEMM MMAEM 9 M WOMMM OF LIND AVDW Sr *0 SW 3NH ST(NOT OPR) AM LM MUM W *0 N MRID Mff GMr� Euc& ZUNI NORM AMOM VERTIM DATM 811 HU MY OF WM UIXR ND IMI AT Tff WERSU=1115 OF UND AVAJE SW AM SW MH MW OM) BEA" Z= FEET MV WMEINT Nt 1551 AT UM ADAX M AM SW 2=1 ST(WT WEN) RMTM 7.1-32 FEET wA mqi: 7w wmmw mm ew oF uw srmwa we FEET w OF THE conum or gumma cpm ON HDM ME OF 301 STREET 50IS1IVEST, ELEVATION 1"2 FEET WA &kf?- 09MD 911M AT SIMEAST OMER MORETE TRANSI*WER, 1175 FEET WEST OF 9MOG1001( OM CENTERILK AM 12A FEET NORTH OF 13AM OF WALK M NMTHI SCE SMITMEST 34TH STREET. GEOTION 21.10 FM TOPOGRAPHIC MAMffi NOTES: W IdAI' MW HEREON IS 7W RE W OF A TOPOWAKIC SN&Y I IXIANIE KWM & AMOMM M M" CINKM ON NIM 21, 2=56 ALL DOW MUES 511010 HUM WERE F13.D TO AS A NEW OF A YNX MIT -OUT UM DIE MIJRSE OF DE Mb "M W.* WMWM & MMMUM IM 044) ASUMB ND UPOM FOR TFIE MaIRAM OF RE ILITM Miliff-UH. MIA ASSLUES W UMM, BMW SAD VM FUR ANY RIUM RWACE FEAM WMFIrATIM6 OR OmCWwnDN ACMM DW kW 00" WMN OR AMOW THE PERIlEn OF TM ORNILY. CIXIXT DA ' 425/4&1-S7�) FOR SITE LMTES A10 VEIRFrATMN& ROAD C0904M & MONUWENT IN CASE — — — — — — ROAD Raff-1OF-WAY AiD, PRCLW BD CH ........... z ...... . .. BULDW, x PK NAIL (MITROO r— FENCE LIME a NEW AND CAP CMIXOR KITAVAL (2 FEET) '-K 0XVENT C13161" I'm (10 FEET) 13 mm Dw cam &M STM WM CILLOOM I DIM BULDIING Q MM Mw WIML CLF CRW LW FM CONFER TREE oopc MOM DEODMIS TREE CM CDM111 70 WYK ?K JCL SIGN EEC DITRIM 00arm cm 0 Fmw ow ORWAIENIM 0 SWIM San MIME 20 0 20 40 ON ORDKW( H19H WAM MM POLE WITH U%ff scde Feet Pyc P012YOK MAW PPE Lpff PONE SID SIX Puyr R WATER MUM sw STORK " "w IM am WLVE sm MM SWEIR w*w SEELCKAJIt RAMP OPERAND FLAG DATUM � wo. REVI51011 W DATE APPR ti zf�z.�� I Ait-- �M INE- �Iil N1 1/4, 51 L/4, 3 25. TWP 23 K 14 1 & NW 1/4. Sr 1/4, 8 30. TV n N. 1 5 X T.N. CITY OF SW 34TH STREET off"Is-IN RENTON CULVERT IMPROVEMENT PROJECT HIM= FIGURE ftwnhlq/E Wmi/ftbft Wwk@ DwL EXSTNG SURVEY 05-751 MAP MW-1 o"_1 3 M 133f' W �r ■ ■ rn a a. a A n 4% 10292 MWAAW x CAW a&W AAD cam ak.vvr MAIN mw e.,R `s AAQV yyt; I UWZ ,�yi yw tA+w ft4.S \ 4xcrdk ci4 ME . a ='�+r W#7kT° Si.*N 7dRfk ',fix" LMN F wry i"r, nx crur MR wi t�i SAw cow cooDrAlm ALM prf `R* OMLIKA' ' allmW VAS '' witm xwJ Fir AS tY 4esPk .2 , i"t'..'`.�. 0 15 30 Felt 1I 1/4. SK 1/4. 3 25, TWP 23 14, Q 4 E A N* 1/4, SW 1/4, S 30, aP 23 H. s 5 8, Wx o� CITY OF 5W 34TH STREET a-t RENT ON CULVERT IMPROVEMENT PROJECT F4GURE 4 �� owsu PWnnft/BWldkV/Puek Wks Dept ALTBMT1VE 1 PLAN rr ■ ■ r >y IL a. NOTES: 1. HORQDNTAL OAnk NAD 83/91 VERNAL UKMM: NIIVD 88 2. IJIM INVERT BASED ON AS -BUILT DRWNGS PROVIDED BY THE CITY OF RENTON. INVERTS WILL BE FIELD VERIFIED PRIOR TO 30% DESIGN. 3. REYOVE EXISTING WrARY SEWER PIPE AS REOLIRED TO INSTALL NEW CULVERT CROSSING. PLOG END OF ROWM PIPE WITH CONCRETE 4. NEW SEWER PIPE TO PASS TIRO" NEW STORK DRAIN 11WIOLE WITHIN DUCTILE IRON APE. fiIII I 1 I I 1 Y EX SDMH I RIM 18.16 NEW SSMH ' IE 14.68 I I J STD 3 EX SSMH IX SDMH !�J RIM 1&14 RIM 19.04 i IE 9.44 E: N 14.64 (EX) i CONNECT r ti 1 1E S 14.62 (E7(; EX SDMH TO IX B' S5 LiJ IE SSMH -15 E W 14.59 EX Q i IE 10-15 L .< IE 9.26 2. -0. EXGST 60' CONC STORM — - k 4 Y�� 300 LF Jr SS S=0.40X 4dX = — 300 LF 8' SS 5r.40% 165 LF 9' SS SNEW SSMH I i € NEW SSMH �� 0 IE 11.37 IE 13M _wNEW li TYPE A CURB ANO GUTTER S.W.�, w,4TH STREET —.. _ NEW SSMH I r I IE 14 55 R.O.W. �- f I� ( ABANDON y EX SS I l NEW SSMH r t EX SDMH CONNECT TO EJWNG RIM 2D.40 EX SSMH IE 1 d.75 IE 9.51 IE 10.86 I r 1 1 I PLAN SCAB: 1'=40' s g; 40 0 40 80 R 1 • �' Style Feet I owe ere "` 1'�40' ,.aRR"aC'i4— CITY OF SW 34TH STREET a-ls-os Im �+ RENTCiN CULVERT IMPROVEMENT PROJECT FIGURE B No. REVISION ar DATE AM +� � ���'wk +�4f I`+ °iat 5AWR RELOCATION "m AOT N c4Sf c,F cUrrTN* eM114N waYs s opwN y<,1 3 iA'!ys`F..X6 W a +Z"r ,'AtA <°j('^F A' wr xS t� WA—K. ray. may �4 E1V AA P =--ltfT ORN, 'm t.Yfe6' rym-A aq MmR EAX"#.ca@0 3(3 4zalwwwll wllf)? r7€Pr£SEY?S %`^x �'�RA?hrG x"ck1'UF,£S S c3 a"i CIE AS QF AFRE 2,1, 10J0. 0 15 30 Fed et# if4, 3l 5; , 0 20, u 1• ""� �''°°'" OF sw 34TH STREET CITY R CITY O CULVERT IMPROVEMENT PROJECT FIGURE i Works DwL ALTERNATIVE 2 PLAN r �w.r wr Lu w D (D NOTM- 1. THIS FIGURE SM AL SD*)MTIC PLAN M TEMPORARILY MW FIM 1W "4W00K CRIML FINAL PLAN WILL BE DESKXM BY THE CONTRACTOR. BUFFERWEn.Am BUFFER WETL" BOUNDARY 01 f WEFLAND ie^ 48' DIA TDAPORWY BOLNDW DKUr" PEES 7 7-' 91:: TDAICIRMY- )MIORWY . ...... COTEFFERnAM . . .............. BDUNDARY . . ..................... WERMD . . ......... . aofmm 4; f ...... .... M::;:1 50' 0 �v C--- WERMD 5---4 . z BUFFER WETLAND BUFFER \L PLAN SCALE V-2V NT, 1/4. M 1/4. 6 25, TWP 23 N, 9 4 9 & W 1/4, 9W 1/4. 3 30. TWP 2S N. P. 5 B. WIN. WS -'WRsZY RVW17-INTS 7HE YPOLWA0.49 PEA PJFFS A!� TWY S(;S'M OV VX AS C.,- AAW 2?, 20M SW -34TH STREET CITY OF CULVERT IMPROVEMENT PROJECT ME WIN 20 0 20 4D CAD RENTON FIGURE 9 AT F'U SM4 Pbmk%/8wMWW1�bk Works Upt TEMPORARY DIVERSION PLAN scar r Scala Feet NO. Reis BY ME APM S W. 34 ph ST. PEA PLAN 9-9 xSOW s+wweo MAN$ • ;. ''�^,.. � � .a fsT .n * S'°*?1^,n`��y� pw`^y'yun �,,�'.. Ws._»� ^�u^rr F.� '}v VYV7f ix _ 0 III, 3r'I 1 Mt .15 Ylf(i1$ 'll•fE � 3nN3AV 0 I'1 i o 'skisn-wjl�.j'- .01 01133.W3 1 ,.GR 3 6 4pW0 +/ rX1E601p ✓•`3y1A1 9 1fFtlL In 0 0 e � M89NINd5 y� 1F0'IJ i Id A33H6 33G T3 1 GGHI 3411 N%vw 09. 11 IL i Y r ImqkI, _ c... 1 .. ..,. ._ v� Ir.4 A 0 1' Ol � —� M--,NmNK —. 3i1N3AV Q N 11 Stag u ' f � 0 I' �1 M � WY g (Dso� fy r N Uf So i 1 ter'-xrY" F z zz S pjO "v� •° 12! 1 o all c wd w. •wo:g A� ilp� ! � a k�P a � g 13M1V.F0-X)0H&19dS Z�V�M 1x A4MH21 tld A3717A =i �y r' r .... ,y,.._ .. T No. 9 - SW 34th Street, facing west from culvert crossing No. 2 - SW 34th Street, facing east from culvert crossing City of Renton SW 34th Street Culvert Replacement Field Reconnaissance Photos VjAr ' .r �`•-�;.G`i� L. ! "� `�LT+,a1`:!_F''IC'' `�e,�+t'�I�k'�`',,�- ° r �f y , - s 4 - ' •��,.i"T� 'R.I �r 7�r w i. i� i� �t� /-��..� l.y'�.A ',��' � - ... - s No. 3 - Upstream end of culvert crossing SW 34th Street ��� 2 •, �1jy�[�-Z°►1'. y.� -. � .ice_ } / Yi 4� � �y y . �� + �1�1i1` r���* SC-�l6Yl a *��.A 1.'�/. "itiii L `'. '� f.�% - t��� .� ..• �. .'.'t w No. 4 - Downstream end of culvert crossing SW 34th Street City of Renton SW 34th Street Culvert Replacement Field Reconnaissance Photos Appendix B WETLAND DELINEATION AND STREAM RECONNAISSANCE TECHNICAL MEMORANDUM Technical Memorandum City of Renton -- 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Prepared for: R.W. Beck 1001 4th Avenue, Suite 2500 Seattle, WA 98154-1004 Prepared by: 10 Jars & Stokes 11820 Northup Way, Suite E300 Bellevue, WA 98005 May 24, 2005 City of Renton - 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Technical Memorandum Prepared for: R.W. Beck 1001 4th Avenue, Suite 2500 Seattle, WA 98154-1004 Contact: Michael Giseburt Prepared by: )7 n Jones & Stokes 11820 Northup Way, Suite E300 Bellevue, WA 98005 Contact: Andy Wanes 4251822-1077 May 24, 2005 This document should be cited as: Jones & Stokes. 2005. 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Technical Memorandum. May 24. (AS 05287.05.) Renton, WA. Table of Contents Chapter 1. Introduction..........................................................1 Chapter2. Methods................................................................1 2.1. Waters and Wetlands.............................................................1 Chapter3. Results.................................................................. 2 3.1. Wetland 1...............................................................................2 3.1.1. Vegetation,................................................................3 Hydrology.......................................................................... 3 Soils................................................................................ .3 Upland Conditions............................................................3 3.2. Wetland 2............................................................................... 3 3.2.1. Vegetation.................................................................4 Hydrology.. ......... .............................................................. 4 Soils..................................................................................4 Upland Condibons............................................................4 3.3. Stream Reconnaissance........................................................4 Chapter 4. Regulatory Issues ................................................ 5 Chapter 5. References............................................................ 6 May 24, 2005 List of Figures Following Page Figure I - Regional Vicinity Map of Project Area....................................................................... 2 Figure2. Site Drawing............................................................................................................... 2 List of A radices Appendix A. Corps Data Forms Appendix B. Ecology Wetland Rating Forms City of Renton —E] Chapter 1. Introduction This technical memorandum describes a wetland delineation conducted for the City of Renton, along Springbrook Creels where it crosses 34th Street. The project area is located in Section 30, Township 23N, Range 5E; and Section 25, Township 23N, Range 4E (Figure 1). The purpose of this work is to provide baseline information for environmental permits required for replacement of the culverts at 34th Street. Two wetlands were identified and delineated along each side of Springbrook Creek, upstream and downstream of 34th Street. Springbrook Creek was straightened in this area, and the wetlands run along both sides of the stream. Both wetlands meet the Washington Department of Ecology (Ecology) definition of a Category III wetland, for which the City Code (4-3-050) requires 50-foot buffers. The ordinary high water mark (OHWM) was delineated along the banks of Springbrook Creek 100 feet upstream and downstream of 34th Street. The delineation methods and both wetlands are described in detail below. Chapter 2. Methods 2.1. Waters and Wetlands On April 19, 2005, Jones & Stokes biologists conducted a wetland delineation along Springbrook Creek, 100 feet upstream and downstream of 34th Street. The biologists used delineation methods from the Corps' Wetland Delineation Manual (Environmental Laboratory 1987) and the 1997 Washington State Wetlands Identification and Delineation Manual (Washington Department of Ecology 1997). Both manuals require the presence of wetland indicators for vegetation, hydrology, and soils before an area is considered a wetland. Orange flagging was hung to indicate the edge of the wetland area. Red and white striped flagging was hung to indicate the location of sample plots. Flags were numbered in sequence on each side of the stream. May 24, 2005 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Technical Memorandum Wetland habitat types are based on the U.S. Fish and Wildlife Service (USFWS) wetland classification system (Cowardin et al. 1979), which categorizes wetlands according to plant community types and hydrologic regime. This system is commonly used by local jurisdictions to help determine wetland functions and values. Wetlands ratings were based on Ecology's Washington State Wetlands Rating System — Western Washington (Ecology 2004) and the City of Renton's wetland classification system (Renton Code 4-3-050). The OHWM along Springbrook Creek was delineated based on evidence of frequent inundation, including: scour, water -stained vegetation, water staining of culverts, and deposition of drifting vegetative debris. The regulatory definition of ordinary high water, is found in RMC 4-11-150: "On lakes and streams, that mark found by examining the bed and banks and ascertaining where the presence and action of waters are so common and usual, and so long continued in all ordinary years, as to mark upon the soil a character distinct from that of the abutting upland..." Chapter 3. Results Jones & Stokes biologist identified and delineated two wetlands within the project area. Both wetlands are narrow, straight riparian wetlands along Springbrook Creek. The biological and physical features associated with both wetlands are described below. OHWM followed very closely to the wetland boundaries. Wetlands and OHWM are shown graphically in Figure 2. 3.1. Wetland 1 Wetland 1 is a narrow riparian wetland that runs along both sides of Springbrook Creek upstream of 34th. Wetlands on both sides of a narrow stream (less than 50 feet) can be considered one unit, with the creek a characteristic of the wetland (Hruby 2004). In the project area, the wetland is dominated by palustrine emergent (PEM) habitat. Wetland hydrology is supported by high flows of Springbrook Creek and groundwater. Wetland 1 meets Ecology's definition of a Category III wetland and the City of Renton's definition of a Category 2 wetland because it is greater than 2200 square feet and is not isolated (associated with Springbrook Creek). Wetland 1 is not City of Renton �� �SSS� Jones &Stokes Figure "- Regional Vicinity Map of Project Area SW 34th Street Culvert Replacement Project ='" THE NORTHEAST OF THE SOUTHEAST OF SECTION 25, TOWNSHIP 23 NORTH, RANGE 4 EAST AND L, q: THE NORTHWEST OF THE SOUTHWEST OF SECION 30, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M. CITY OF RENTON, COUNTY OF ICING, STATE OF WASHINGTON f ,7_ r E r I.L ) rrr• r���. ]. �^ ICErYE F 1r l r .'fir uI � t ]O F n.silr r I z WETLAND BUFFER (50 FEET} r";r r ti J i 1 WETLAN BUFFER (50 FEET)D BU i IBOPL r wERMD 1 3 �L L. ]c!Z E I iv m � .... p ... <.., ..., I ]E i w — 1 x WEnAN n.:.aul r L F ., -... C9EFa I 794mRy10M f1®r yy 1 f _ 1 . 1 1 I II LN, 13 T FE F. I E TTl I U x +'iFULI 1F{4 rU [IMF L-� O S 'Sb 1?FE "LUAUS �• - til •• •.. E. r�rK PI Ew goua {.5 �SIRe.I `m ..... L _ : I spa T. 1 wl 1r,7k c Ic run u+o IrAor I'I+ sl+ a P K. 6 F a OF 41 17 LLL -i14N r. 51 .LrE ) �� { �11 .SP1� • � U{ -, WEfEiWD BUFFER (50 FEET} � wEEW BUFFER FEM �. (50 tc r� -r5P i� It f I! 15 sA r935 11 CDrr'ai •. E 1 e Ei 7 E I i I � I � N's�r LlP1 ANEi'UE �w `E 1k,M EM i C� ClI- + .: MaAIENS. P)III ). 1ri 0 P[ r)x r1�lAN',1 r1s col ECEN•Trr ;x r[n CP +SF ')' R4kW,,l NOT S H.W70NTAL OATLfMA; NORTH Al DATUM W9E. HELD NORTH 01'35'41" EAST 80WET71 JAOHUMEIHTS AT THE NTERSE00H OF UND AVENUE SW AND SW WM ST(NOT OPEN) AND UND AVENUE SW AND SW 23RD ST(),W OPEN), VERTICAL DATUM; NORTH AMERIICAN VERI)CEL DATUM JIB. HELD CITY OF RE)tM MCHUMENT NO. 1861 AT THE WTElSEC IM OF LAND AVENUE SW MID SW 30TH ST(NOT OPEN) aEYA10H 20.D0 FEET AND MOMIMENT NO. 1551 AT LWO AVENUE SN AND SW 23RD ST(HOT OPEN) ELEVATION 21-32 FEFT. DNIA D1411: TOP NORTHWEST BASE BOLT OF UGHT STANDARD 1126 FEET EAST OF THE CENTERUNE OF SPRRIGUMK CREEK ON NORTH SCE OF 34TH STREET SCURfIYESIT. i7kVATIOH I8.92 FEET DEN BMg2: MSEIM SOILARE AT SOUTHEAST CORNER CONCRETE TPANSFORMRR t175 FEET NEST OF SPRNI 8RM CRIB CENTERLINE AND 1ZD FEET NORTH (IF BACK OF WALK ON NORTH WE SOUTHWEST 34TH STREET ELEVATION 91.10 FEET THE MAP SHOWN HEREON IS THE RESULT OF A TOPCIitMHIC SURVEY BY DWNE ILA rMAN 3 ASSDCNTES W. (DNA) COMPLETED ON APRIL 21. 200& ALL EK0M4O UIRITES EiHM HEREIN WERE FELD TED AS A RESULT OF A UTUTY PAMT-0UT DURING THE COURSE OF THE HELD SURVEY. OUAAE HARUMAI d AS90dATFS. NO (DIN) ASSUMES NO LKKP FOR THE ACCURACY OF THE UDL)TY PAINT -OUT OHA Al NO LLABLITY, BEYOND 34 DATE, FOR ANY fTRLkE SURFACE FEATURE MOOIFICAi1OH5 OR CORMUCTION ACINTIIFS THAT MAY OCCUR WTIHML OR Al THE PER60ER OF [HAS SURVEY. CONTACT DEN (425/4W-5355) FOR S1E UPDATES AND 4ijWOTKJHS LEGEND .... ... ROW NENIVRJHE 9 MONUMENT W CASE ROAD WHT_OF_NAY $ PROJECT RFNCHMA" BUILDING x PK NAIL (CONTROL) —� FENCE LINE REBAT AND CAP - - CONTOUR iKrERVAL (2 FEET) CULVERT — CONTOUR ENOE1i (10 FEET) - STORM DRAN CATCH BASH -- — --- — — — WER,WD BOUNDARY STORM DRAW CIEAMCIJT _ . _ . _ . _ .. WETUND BUFFER (50 FEET) STORM DRAM MANHOLE BLDC tMKl.D1lC CONFER TREE ELF CTNN LINK FpiCE DEC;CljKL15 TREE CON[ CONCRETE -' SKN CMP CCRVXATED METAL PIPE POTHOLE ECC WRODED CONCREM CURB % SANITARY SE'MER MANHOLE I SCALE ORN ORN911EMAL uTUTY FOIE WITH IMiLT - _ DMF OD(AIWIAY HIGH WATER M. um POLE r'1� 20' PAC FOLrmm cKDmE Pff _ WATER HIDPNIT SP SONL PLOT WATER VALVE SDMH STORM DRAIN MAN40LE ,:: WHEELCW RAMP SSMH SAMURY SEMER MANFIOLE P WED.A1p FUG UTILITY POTHOLE RESULTS: DATE 06/t2/2005 Figure 2. Site Drawing 3dth 5traet Culvert Replacement Wetland Delineation and 5tr2arn Reconnaissance Technical memorandum severely disturbed (Category 3 wetland), and does not possess the high quality attributes of a Category 1 wetland. The City of Renton requires that Type 2 wetlands are given a 50-foot buffer. 3.1.1. Vegetation The wetland is completely dominated by reed canarygrass (Phalaris arundinacea) with occasional stinging nettles (Urtica dioica). In two field sample plots, over 50% of the dominant vegetation had a wetland indicator status of "FAC" or wetter. This field indicator meets the Corps requirements for evidence of wetland hydrophytic vegetation. Hydrology The hydrology of Wetland 1 is associated with a high groundwater table and high flows of Springbrook Creek. One sample plot was saturated to the surface while another was saturated to the surface with standing water S inches below the surface. Standing water and saturation in the upper 12 inches of the soil profile meet the Corps requirements for evidence of wetland hydrology. Sons Two soil samples were taken along the wetland delineation boundary. One sample had a low chroma value of 1 in the upper 10 inches of the soil horizon. The other sample had a chroma value of 1 in the top 10 inches with mottles. Chroma values of 1 with or without mottling in the tipper 10 inches meet the Corps requirement for hydric soils. Upland Conditions Upland conditions around Wetland 1 begin with a change in vegetation that coincides with the topographic break at the toe of the hillslope that runs the entire length of Springbrook Creek. Upland habitat is dominated by Himalayan blackberry (Rubes discolor) on the west side, and various invasive herbs and shrubs on the east side. Vegetation observed includes Himalayan blackberry, stinging nettle, reed canarygrass, catchweed (Galium aparine), bitter nightshade (S'olanum dulcamara), poison -hemlock (Coniuni maculatum), and silver cottonwood (Populus alba). 3.2. Wetland 2 Wetland 2, similar to Wetland 1, is a narrow, riverine, flowthrougb wetland that runs along both sides of Springbrook Creek downstream of 34`E' Street. Like Wetland 1, Wetland 2 is considered one unit. In the project area, the wetland is dominated by palustrine emergent (PEM) habitat. Wetland hydrology is supported by high flows of Springbrook Creek and groundwater. 3 __... May 24, 2005 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Technical Memorandum Wetland 2 meets Ecology's definition of a Category III wetland and the City of Renton's definition of a Category 2 wetland because it is greater than 2200 square feet, is not isolated (associated with Springbrook Creek), is not severely disturbed (Category 3 wetland), and does not possess the high quality attributes of a Category 1 wetland. Type 2 wetlands in the City of Renton are given a 50-foot buffer. 3.2,1. Vegetation Wetland 2 is completely dominated by reed canarygrass. Therefore, in the two field sample plots, over 50% of the dominant vegetation had a wetland indicator status of "FAC" or wetter. This field indicator meets the Corps requirements for evidence of wetland hydrophytic vegetation. Hydrology The hydrology of Wetland 2 is associated with a high groundwater table and high flows of Springbrook Creek. One sample plot was saturated to the surface while another was saturated to the surface with standing water 4 inches below the surface. Standing water and saturation in the upper 12 inches of the soil profile meet the Corps requirements for evidence of wetland hydrology. Soils Two soil samples were taken along the wetland delineation boundary. One sample had a low chroma value of 1 in the upper 10 inches of the soil horizon. The other sample had a chroma value of 2 in the top 10 inches with mottles. Chroma values of 1 and chroma values of 2 with mottling in the upper 10 inches meet the Corps requirement for hydric soils. Upland Conditions Upland conditions around Wetland 2 begin with a change in vegetation that coincides with the topographic break at the toe of the hillslope that runs the entire length of Springbrook Creek. Upland habitat is dominated by Himalayan blackberry on the west side, and mostly mowedibare ground on the east side. Vegetation observed includes Himalayan blackberry and reed canarygrass. 3.3. Stream Reconnaissance Washington State has designated Springbrook Creek a Shoreline of the State (WAC 173-18-210). As a Shoreline of the State, Renton classifies Springbrook Creek as a Class 1 stream with a standard buffer width of 100 feet. In the vicinity of 34`" Street, Springbrook Creek is a modified straight, trapezoidal, channel. Riparian vegetation is limited, dominated by reed canarygrass. Several small (i- to 5-inch diameter) willows grow to the north of 34"' Street, between 30' Street and the outlet of the City of Ranton g 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Technical Memorandum existing Sprinbrook Creek culverts. Stream gradient is low, and habitat is essentially one long glide. In places, reed canarygrass has invaded the active channel. Stream substrate is primarily a mixture of gravel and sand with some finer sediment. The existing culverts at 34`h Street are low gradient and do not appear to impair fish passage under normal flows. Salmon and trout are known to spawn upstream of the site. Kerwin & Nelson (2000) report chinook salmon, coho salmon, cutthroat trout, and steelhead trout all use Springbrook Creek and its tributary Mill Creek, located well upstream of 34`h Street. Although velocity through the existing 34th Street culverts would be highest during peak flows, it is likely that even at peak flows, the culverts do not prevent fish passage. However, no velocity measurements have been taken to confirm this supposition. As is typical of modified urban streams, Springbrook Creek contains little woody debris or other habitat forming structure. No large woody debris was found in the stream or along its banks for at least 200 feet upstream or downstream of 34h Street, on April 19, 2005. Chapter4. Regulatory Issues Several federal, state, and local regulations affect activities in wetland areas and their buffers. Agencies that have jurisdiction over activities in wetlands include, but may not be limited to. ■ Corps ■ Ecology; and ■ City of Renton. The Corps administers Section 404 of the Clean Water Act, which regulates the discharge of dredged or fill materials into Waters of the United States, including wetlands. For projects requiring Section 404 Permits, the Corps makes the final determination as to whether the area meets the definition of a jurisdictional wetland. Section 401 of the Clean Water Act requires applicants for Section 404 permits to obtain 401 water duality certification from the appropriate certifying agency. In Washington, that agency is the Ecology. Section 401 certification ensures that projects discharging to Waters of the United States, including wetlands, fall within specific water quality standards. Conditions of the 40 1 Certification become 5 May 24, 2005 34th Street Culvert Replacement Wetland Delineation and Stream Reconnaissance Technical Memorandum conditions of the Corps 404 Permit. Project information should be submitted to Ecology for approval. Applicable City of Renton regulations include RMC Title IV - Development Regulations: Chapter 3 (Environmental Regulations) and Chapter 4 (Property Development Standards). Section 404 and 401 Permits require the submittal of a Joint Aquatic Resources Permit Application (JARPA) to the above -mentioned agencies for approval before initiating any activities within the wetland identified on -site. Depending on the proposed activity that occurs in the wetland, a wetland report and wetland mitigation plan are typically requested by the Corps, Ecology, and the local jurisdiction, as part of the DARPA submittal. Chapter 5. References Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. 1979. Classification of Wetlands and Deep Water Habitats of the United States. (FWS/OBS-79/31.) U.S. Fish and Wildlife Service. Washington, DC. Environmental Laboratory. 1987. U.S. Army Corps of Engineers wetlands delineation manual. (Technical Report 4-87-1.) U.S. Army Corps of Engineers Waterways Experiment Station. Vicksburg, MS. Hruby, T. 2004. Washington State wetland rating system for western Washington — Revised. Washington State Department of Ecology Publication #04-06-025. Kerwin, John and Nelson, Tom S. (Eds.). December 2000. "Habitat Limiting Factors and Reconnaissance Assessment Report, Green/Duwamish and Central Puget Sound Watersheds (WRIA 9 and Vashon Island)." Washington Conservation Commission and the King County Department of Natural Resources. Reed, P.B., Jr. 1988. National list of plant species that occur in wetlands: northwest (Region 9). St. Petersburg, FL. Prepared for U.S. Fish and Wildlife Service wetland inventory, Washington, DC, Renton, City of. Municipal Code Chapter 4-3-050 — Environmental Regulations and Overlay Districts. Washington Department of Ecology. 1997. Washington state wetlands identification and delineation manual. (Publication No. 96 94.) March. Olympia, WA. City or ,Rector 6 Appendix A �orUs Data Forms DATA FORM ROUTINE. WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) Projecl/Site: _51 L_, t. ver f E �,C['M(�Li Date: O�^ Applicant/Owner: t / � County /. K l/Aj& Investi ator s I State: Do normal' circumstances exist on site? Yes No Community ID: i Is the site significantly disturbed (atypical situation)? Yes o �NTransect 10: ❑ Is the area a potential problem area? (II needed, explain on reverse.) Yes r rva Plot 1D: f VEGETATION Dominant Plant S ies Stratum Indicator Dominant Plant Species Stratum Indicator 1-V/IRol* r dropCCZt���__!L� � g 3. 11. 4. 12_ 5. 13. 8, 14. 7. 15. 8. 16. Dornrrrent Species ................ ....... —........ ........................... - ........ .............. ..... Percent of dominant ss _ ies that are OBL, FACW or FAC (excludingI • l �FAC- . Remarkf s: ! CC'C C"Mdzt ,�I e�'f HYDROLOGY Recorded Data (Describe. in Remarks): _ Stream, take, or Tide Gauge —Aerial Photographs r_ Other Y No Recorded Data AvailaUe Field Observations: Depth of Surface Water: Depth to Free Water in Pit: Depth to Saturated Solt: Wetland Hydrology Indicators Primary Indicators: Inundated Saturated In Upper 12 Inches _ Water Marks _ Oritt Lines _ Sediment Deposits — Drainage Patterns in Wetlands Secondary indicators (2 or more required): (in.) Oxidized Root Channels In Upper 12 Inches Water -Stained Leaves 'l (in) Local Solt Survey Data FAC-Neutral Test *; 1� (in.) _ Other (F)�ptain in Remarks) Remarks: /��'B� {a%f ����1 r'.4�� /� f E"3'1>f I�r Mcyj dC?t"� tr►�C. SODS Map Unit Name (Series and Phase): Drainage Class:C70iU�fGL r Field Observations Taxorrorny (Subgrxwp�: Contirtn Ma T ? Yes No .... iD." ...Yid....... Prork DescriSgions, Depth finches) Horizon Matrix Color _ (Munsetl Moil Mottle Colors (Mansell Moist) Mottle Texture, Concretions, Structure.,_elc. �Abundance/Conlrast _ Hydric Soil Indicators Hlstosol Histic Epfpedon Sulrxtic Odor Aquic Moisture Regime 32�Reducing Conditions Gleyed or Low-Chroma Co?ors Remarks: WETLAND DETERMINATION Concretions High Organic Content in Surface Layer In Sandy Soils Organic Streaking In Sandy Soils Listed on Local Hydric Soils List Listed on National Hydric Soils List Other (Explain In Remarks) Hydrophytic Vegetation Present? No (Circle) (Circle) Wetland Hydrology Present? No Hydric Solis Pncsent? Yes No is this sampling point within a wetland? Yes No Remarks: rV-P�t I G✓ '% o f ��r P �.v/��it r'M of !-f • 4 Ucr1 r tiles ,iP cr Y'i'1 Approved by HQUSACE 3/92 DATA FCRM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) ProjecVSite: j�L��/Q`�P'/01r� f� Date:'I I��`// Applicant/Owner: C � \ R&n 1o'County _ ,F Investi ator s ' State: // rGV " Do normal circumstances exist on site? Yes No Community ID: Is the site significantty disturbed (atypical skualion)7 Yes Transect ID: Is the area a potential problem areal (if needed, explain on reyerse.) Yes ro P1at ID: S P — VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator /o 2.a�lclr rr S F Cry/ 1a. �i 3.ltii��u� rSflllO f fO n _:S A��f a.tAd r -1t" IA utli 2 rL 12. IT s 6. GilFLiM r,Ia.C'c4aIr �! - 14. 7._ 16 Ucr /0 5 8. 16. ' Domrnant Sae.... Percent of dominant species that are OBL. FACW or FAC (excluding FAC-). — Y Remarks: Ply" ) to rx JtT V V e'5 VC HYDROLOGY Recorded Data (Describe in Remarks): Wetland Hydrology Indicators _ Stream, Lake, or Tide Gauge Primary Indicators' Aerial Photographs Inundated Other /N, _ _ Saturated in Upper 12 Inches Water Marks _ Recorded Data Available _� Drill Lines _ Sediment Deposits Drainage Pattems In Wetlands Fleld Observations: Secondary Indicators (2 or more required): Depth of Surface Water. (Sn.) _ Oxidized Roct Channels In Upper 12 Inches _ Water -Stained Leaves Depth to Free Water in Pit: (in.) _ Local Sail Survey Data _ FAC-Neutral Test Depth to Saturated Soll: (in-) _ Other (Explain in Remarks) Remarks: p f\%�il�Q{/c dl I � y SOILS Map Unit Name ,t jF I! C (series and Phase): fir' �4." I ?/Gt Drainage Class: r tf G��flCar' Field Observations TaYonConfirm Mapped Type? Yes No Profile Descriptions: Depth Matra Color Mottle Colors Monte O-I6 0),g-3 Hydric Sal Indicators: Hlstosot HisW Eplpedon Sutfidic Odor Aquic Moisture Regime Reducing Conditions Gleyed or Low-Chroma Color; Remarks: 'Vo X14(C Sa-,A/ / C471r-9 WETLAND DETERMINATION T, �raJell �oaM etc. Concretions High Organic Content in Surface Layer in Sandy Soils Organic Streaking to Sandy Soils Listed on Local Hydric Soils List Usted on National Hydric Soils List Other (Explain In Remarks) Hydrophytic Vegetation Present? Yes (Circle) prcke) Wetland Hydrology Present? Yes Hydric Soils Present? ' Yes o Is this sampting point within a wetland? Yes Nv Remarks- r/ fu %¢411. V �G a q Approved by HOUSACE X92 r DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) / r ' Project/Sile:_......�51 Date: Apptican(10"ec C11,11 County. /v lnvestiat4r(s�: State: W___� .� Do nonnat circumstances exist on site? Yes No Community ID: &' Is the site significantly disturbed (atypical situation)? Yes No Transect ID: Is the area a potential orWem area? of needed, explain on reverse.) Yes ( No Plol 10: 3 r r Dominant Plant SDeeccies Stratum Indicatto/r/ Dominant Plant Species Stratum Indicator {/ 2- 14. 3. 11. 4- 12. S. 13. 6- 14. 7. 15 a. 1 16, Dominant Species ........................ .................... ........................................ •--------.-.-..-.......-....-----------------------------....-........................................... Percent of dominant species that are 06L FACW or FA0 excludin FAC- . Remarks: F r r �t �c f �, — rc HYDROLOGY Recorded Data (Describe in Remarks): Stream, Lake, or "fide Gauge — Aerial Photographs _ Other V Na Recorded Data Available Field Observations: Depth of Surface Water: Depth to Free Water in Pit: Depth to Saturated Solt: Welland Hydrology indicators t Primary Indicators: _ Inundated 7�Saturated in Upper 12 Inches Water Marks _ Drift Lines _ Sediment DeposRs Drainage Patterns in Wetlands Secondary Indicators (2 or more required): _ Oxidized Root Channels In Upper 12 Inches Water -Stained Leaves Local Soil Survey Data FAC-Neutral Test _ Other (Explain In Remarks) Remarks' F{ LC � 0 SOILS ?Aap Unit Name (series and Phase): �f .r • ! t i t �. f FsY :! — _ Drainage Class i' .' .' � U-t voe Field Observations Taxonomy (Su6groUp�; Confirm Mapped Type? Yes No Profile —Descriptions: Depth Matra Color Mottle Colors Mottle inches) Horizon (Mansell Mois1) (Mansell Moist) Abunc Hydric Soil Indicators: Hlstosoi Histic Epipedon Sulfidic Odor Aquic Moisture Regime Reducing Conditions ate- Gleyed or Low-Chroma Colors Remarks: WETLAND DETERMINATION Te)ture. Concretions Concretions High Organic Content In Surface Layer in Sandy Soils Organic Strealdng In Sandy Soils Listed on Local Hydric Soils List Listed on National Hydric Soils List Other (Explain In Remarkr) Hydrophybe Vegetation Present? No (Circle) (Circle) Wetland Hydrology Present? No Hydric Soils Present? ' es No Is this sampling point within a wetland7 Yes No Remarks: y[ �i Approved by HQUSACE 3/92 DATA FORM ROUTINE WETLAND DETERMINATION (1987 GOE Wetlands Detineation Manual) ProjecUSite: _ �� ! Date: `D J Applicanl/Owner: ti +� County. ! � Investir�ator(s];, �- state: VV p Do normal circumstanczs exist on site? No Community ID: _ Z, I Z_ Is the site significantly disturbed (atypical situation)? Yes -Na Transect lD: Is the area a potential problem area? (if needed. explain on reverse.) Yes no 1 Plot ID: -5-P ~ 4 VEGETATION Dominant Plan_t/SSpecies_ Stratum Indicator Dominant Plant Species Stratum Indicator 9. 3. t1. 4. 12. G. 14, 7. t 5. 8. 16. ' Domrnanf Species �i �.P �1 ':' • i��.' f rJ� a�i/3i� .................. ..............................--,-...------r�...-•------------------�.. Percent of dominant species that are 08L FAGW ........ ....-_� or FAC excludnc- FAC- . .,....-...-------------........,......................................................... d Remarks: f� !� �fr?'� / rG�2f.�,_ HYDROLOGY Recorded Data (Describe in Remarks): Stream, Lake. or Tide Gauge Aerial Photographs Other IN. Recorded Data Available Field Observations: Depth of Surface Water: Depth to Free Water in Pit: Depth to Saturated Soil: Remarks_/V & �r/ "I }' j � r F Wetland Hydrology Indicators Primary Indicators: Inundated Saturated in Upper 12 Inches —Water Marks Drill tines Sediment Depostls Drainage Patterns in Wetlands Secondary Indicators (2 or more required): _ Oxidized Root Channels in Upper 12 Inches _ Water -Stained Leaves _ Local Soil Survey Data FAC-Neutral Test _ Other (Explain in Remarks) SOILS Map Unit Name J (Series and Phase): )Pg &7 je; r t i rMf _ _ Drainage Class: aig Field Observations Taxonomy (Subgroup: Confirm Ma��sed Type? _Yes No Profile Descriatfons: Matrat Color Mottle Colors Mottle ) 0 yp- 113 Hydric Soil indicators: Hlstosd Histic Eplpedon Suffrdic Odor Aquic Moisture Regime Reducing Conditions Gleyed or Law-Chroma Colors Remarks:r% J [- // , WETLAND DETERMINATION j low 44 Concretions High Organic Content in Surface Layer In Sandy Soils Organic Strealdng In Sandy Soils Listed on Local Hydric Soils List Listed on National Hydric Solis List Other (Explain In Remarks) Hydrophytic Vegetation Present? Yes (Circle) (Circle) Wetland Hydrology Present? Yes Hydric Soils Present? Yes Na Is this sampling point within a wetland? Yes No Remarks-O,'I( GfL1� 6/f° ` G�{f !A. /�",e�Gp:� R / C0I Vas I V ti1 /a�r��/• .� Approved by HQUSACE 3/92 DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) Project/Sde: Jin) I f f�J./ lam t - ' !� _�'lfsr � Dale: Applicant/Owner: / County. InvestState: igator{s�;� J�u Do normal circumstances exist on site? Yes No Community 10: Is the site significantly disturbed (atypical situation)? Yes SN Transect tD: is the area a oatentiat problem area7 (€f needed, explain on reverse.) Yes Plot ID: f� LfLxKAVIldraW Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator 1,FAaaris(?a CW s. iLt",LtaCZ 2. 10, 3. 11. 4. 12. 5. 13, 6. 14, 7. 15. 8. 16. iaomrnant Species ............................—................ ............ ...-................................. --...........------....---------...............................................................,..-....--..... Percent of dominant species that are 08L, FACW or c FAC (excludirr FAC-). o C a � r Remarks:�f,rl f Y, r• 4( C� L f , 0 V- � � A� HYDROLOGY Recorded Data (Describe in Remarks): Stream, Lake, or Tide Gauge Aerial Photographs /_ Other N, Recorded Data Available Field Observations: Depth of Surface Water. Depth to Free Water in Pit: � (in-) Depth to Saturated Soil: aC (in.) Wetland Hydrology Indicators Primary Indicators: Inundated aturated in Upper 12 Inches Water Marks _ Drift Lines _ Sediment Deposits Drainage Patterns in Wetlands Secondary Indicators (2 or more required): Oxidized Root Channels In Upper 12 Inches Water -Stained Leaves _ Local Sol[ Survey Data _ FAC-Neutral Test Other (E)qDlain in Remarks) Remarks: SOILS Map Unit Name /y (Series and Phase): li/! _ ,�17_ _ Drainage Class: C�►/ Field Observations Taxonorn 5u rou Confirm Mapped Type? Yes No ......._.. ........... ProMe_Uescriptions: Depth o- ) Matrix Color Mottle Colors Mottle Horizon (Munsetl Moist) (Munsell Moist) Abundanc.&Contrast Hydric soil Indicators Hlstosol Hisbc Epipedon Sulb6c Odor Aquic Moisture Regime Reducing Conditions Gleyed or Low-Chrorna Colors Remarks: WETLAND DETERMINATION etc. Concretions Nigh Organic Content In Surface layer In Sandy Soils Organic Streaking fin Sandy Soils Listed on Local Hydric Soils list Listed on National Hydric Sods List Other (Explain In Remarks) Hydrophytic Vegetation Present? 1 No (Circle) I (Circle) Wetland Hydrology Present? No Hydric Soils Present? " Yes No is this sampling point within a wetland? Yes No Remarks:}l94�fos�j� f� , 14 i 4Ki v e V", - Approved by HQUSACE 3/92 DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) Project/Site- J W/ T (_ ��'fi J` '� �t/u Date:/ I — P ApplicanUOwner: ! r c l� fir ( D^/1 - -- - — County. tom- l Do normal circumstances exist on site? Y No Community ID: Is the site significantly disturbed (atypical situation)? Yes N Transect 10: Is the area a potential wahlom area? {If needed, explain on reverse.) Yes / N(ib Plot ID: �s ]-' r VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant S ies Stratum Indicator 2. ',� r - f.�,., , 10, •4. 12. 5, 13. 6. 14, 7. 15. • baminan� Species a . Percent of dominant species that are OBL, FACW or FAC excluding FAC- . RemarkS:�./�2�j HYDROLOGY Recorded Data (Describe in Remarks): _ Stream. Lake, or Tide Gauge Aerial Photographs Other zNo recorded Data Available FlOd Observations: Depih of Surface Water: Depth to Free Water in Pit: Depth to Saturated Soll' Remarks: � f o Wetland Hydrology Indicators Primary Indicators: _ Inundated _ Saturated in Upper 12 Inches _ Water Marks _ Drift Lines _ Sediment Deposits Drainage Patterns in Wetlands Secondary Indicators (2 or more required): (in.) Oxidized Root Channels In Upper 12 Inches Water -Stained Leaves (in.) Local Soil Survey Data _ FAC-Neutral Test Other JExpWn In Remarks) R"0 1&0 Map Unit Name y (Series and Phase): rr4 i�l {� ��l /�� M Drainage Class: Oo Qes�fa — Field Observations Taxonomy (Su6�roup�. Confirm rs,tapQed Type? Yes No Prvrile 12escdoLons, Depth Hydric Soil indicators: Matrix Color Mottle Colors Mottle HistomA His6c Eplpedon Sulfidic Odor Aquic Moisture Regime Reducing Conditions Gleyed or Low-Chroma Colors WETLAND DETERMINATION ,//� Q 44 Concretions High Organic Content in Surface Layer in Sandy Soils Organic Strealdng In Sandy Soils Listed on Local Hyddc Soils Us# Listed on National Hydric Soils List Other (Explain in Remarks) Hydrophytic Vegetation Present? Yes (Circle) (Circle) Welta» Hydrology Present? Yes Hydric Soils Present? Yes Is this sampling point within a weetland? Yes Ala Approved by HQUSACE 3192 DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) Project/Site: - W _1L •► ff`1� f` ! !u �f �.��='�� pate. jQ ' P Applicant/Owner: C r () County: T tn�esligator(s�: r State: fit/ ..-------••--- 1 Do normal circumstances exist on site? Y No Community Ip: Is the site signiricantly disturbed (atypical situation)? Yes o Transect 10: Is the area a potential problem area? (1f needed, explain on reverse.)_Yes No Plot ID: VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator r / 2_ 10. 3. it, 4. 12. g, 13. 6. 14_ i 5. 7. 8. i 6. ' Dominant Species ......................---........._.............................................................................................................. ._../....................... ......... ................. ........ Percent of dominant species that are 061-, FACW or FAC excludin FAC- . iiemarks:_- HYDROLOGY Recorded Data (Describe in Remarks): _ Stream, Lake, or fide Gauge Aerial Photographs /_ Other No Recorded Data Available Field Observations: Depth of Surface Watec Depth to Free Water in Pit:(in) Depth to Saturated Solt: (in.) Wetland Hydrology Indicators Primary Indicators: _ Inundated ,,-'Saturated in Upper 12 Inches Water Marks Drift tines —_ Sediment Deposits Drainage Patterns in Wetiands Secondary Indicators (2 or mare required): _ Oxidized Root Channels In Upper 12 Inches _ Water -Stained Leaves Local Soil Survey Data FAC-Neutral Test Other (E.VIain In Remarks) '/� Remarks=4� f. SOILS Map Und Name ,,,j (Series and Phase):Weow;,t Vf Drainage Class: _ �c'��/ Field Observations Taxonomy (SuNrouoj: .Confirm Mapped Type? Yet No Profile Descriptions: E-. Horizon Hydric Soil Indicators: matrix color Mottle Colors Mottle r x1? YX Histosol --Histic Epipedon -�- Suifidic Odor Aquic Moisture Regime Reducing Conditions Gleyed or Low-Chroma Colors Remarks: ,W/ f WETLAND DETERMINATION T. Concretions High Organic Content In Surface Layer In Sandy Soils Organic Streaking In Sandy Soils Listed on Local Hydria Soils List Listed on National Hydric Soils list Other (E)Vain In Remarks) Hydrophytic Vegetation Present? No (Circle) (circle) Wetland Hydrology Present? rx7iP No Hydric Soils Present? ' Yes No Is this sampling point within a wetiand7 �es No Remarks: ��' ,✓��rr 2 L Approved by HQUSACE 3/92 DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) ?rojed15ile; i /� .1 !.. !� <<:�i1i. Date: ' f l ApplicanUO vner: i . r /x1-cr County: ' rI G, I nvestiga tor(s}; r/ Stalei/ ..._.. � Do normal clecurnstances exist on site? Yes No Community ID: Is the site significantly disturbed (atypical situation)? Yes r �� Transect ID: Is the area a pollentialeroblem area? It needed. explain on reverse.) Yes N Plot 10: Sr VEG ETATION Dominant Plant-Se2cles Stratum Indicator Dominant Plant S ies Stratum Indicator 17 /� 9. 2.�1..v 3, i1- 4. 12. 5. 13. 6. 14. 7- 15. g, t 6, ' Dorrvnant Suedes '-------------------------------.......................,..........................................---.--......................----------------.-...............................,.,....... .................. ....... ..... .---------- Percent of dominant s22cies that are OBL FACW or FAC exctudin FAC- . Remarks: HYDROLOGY Recorded Data (Describe in Remarks): Stream, Lake, or Tide Gauge Aerial Photographs Other ' No Recorded Data Available Fleld Observations: Depth of Surface Water: Depth to Free Water in Pit: (in.) Depth to Saturated Soll: (in.) Remarks: Wetland Hydrology Indicators Primary Indicator: Inundated _ Saturated in Upper 12 Inches _ Water Marks Drift Loes _ Sediment Deposits _ Drainage Patters in Wetlands Secondary Indicators (2 or more required): Oxidized Root Channels In Upper 12 Inches Water-Slained Leaves Local Soil Survey Data FAC-Neutral Test Other (Explain In Remarks) Sol Map Unit Name N) (Series and Phase): Drainage Class: Field Observation. Taxonomy (Subgroup: Con._:firm Mapped eN . .............. .... :jype� Yes ............. . o ............ Prortle- Descd2liorts: Depth MatrEK COW Mottle Colors Horizon Q� — ( ors q13 Hydric Soil In,dicato(s. Histk Eopedon Sullidic Odor Aquic Moisture Regime Reducing Conditions Gleyed or Low-Chforna Colors Mottle Abundance/Contrast T IS' etc - Concretions High Organic Content in Surface Layer In Sandy &AIs Organic Strealdng In Sandy Soils Listed on Local Hydric Soils List Listed on National Hyddc Soils List Other (E)T4ain In Remarks) Remarks: t'C �Aa ,I WETLAND DETERMINATION Hydrophytic Vegetation Present? Yer. rNo (Circle) (Circle) Welland Hydrology Present? Yes Hydric Sods Present? Yes No Is th]s sampling point within m wet:artd7 Yes No�) Remarks: !x Approved by HQUSACE 3/92 Appendix B Ecology Wetland Rating Forms i WETLAND RATING FORM — WESTERN WASffiNGTON Flame of wetland known): 6 w Location: SEC 0 TWNSHP. RNGE - attach map with outline of wetland to ratio form .&fPerson(s) Rating Wetland: Affiliation: ADate of site visi#-p DRAFT SUMMARY OF RATING Category based on FUNCTIONS provided by wetland I II III IV Category I = Score >70 Category B = Score 51-69 Category Ill = Score 30-50 Category N = Score < 30 Score for Water Quality Functions Score far Hydrologic Functions Score for Habitat Functions TOTAL score for functions Category based on SPECIAL CHARACTERISTICS of wetland I II Does not Apply Fugal Category (choose the "hi ;hest" category from above) Check the appropriate type and class of wetland being rated. icndM MEN Rtla a` t Estuarine De ressional Natural Herita a Wetland Riverine, Beg Lake -fringe Mature Forest Slope Old Growth Forest Flats Coastal Lagoon Freshwater Tidal Interdunal None of the above Wetland Rating Form— western Washington 1 August 2004 Does the wetland being rated meet any of the criteria below? If 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. SP 1. Has the wetland been documented as a habitat for any Federally listed Threatened or Endangered plant or animal species (TIE species)? i For the purposes of this rating system, "documented" means the wetland is on the '� appropriate state or federal database. SP2. Has the wetland been documented as habitat for any State listed ?Threatened or Endangered plant or animal species? For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. SPI Does the wetland contain individuals of Priority species listed by the WDFW for the state? SP4. Does the wetland have a local significance in addition to its fumctions? For example, the wetland has been identified in the Shoreline Master Program, C/ the Critical Areas Ordinance, or in a local management plan as having special significance. To corn lete the next part o the data sheet you will need to determine the H drogeomor hie Class of the wetland being rated. The hydrogeomorphic 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 Form — western Washington 2 August 2004 Classification of Vegetated Wetlands for Western Washington Wetland Name: Date: 1. Are the water levels in the wetland usually controlled by tides (i.e. except during floods)? ND 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 per thousand)? YES — Freshwater Tidal Fringe NO — Saltwater Tidal Fringe (Estuarine) If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal 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 term "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category I and II estuarine wetlands have changed (see p. ). 2. Is t e topography within the wetland flat and precipitation is only source (>90%) of water to it. NOS go to 3 YES — The wetland class is Flats f If your wetland can be classified as a "Flats" wetland, use the form for Depression.al wetlands. 3. Does the wetland meet both of the following criteria? The vegetated part of the wetland is on the shores of a body of open water (without any vegetation on the surface) where at least 20 acres (8 ha) are permanently inundated (ponded or flooded); At least 30% of the open water area is deeper than 6.6 ft (2 m)? No g to 4 YES —The wetland class is Lake -fringe (Lacustrine Fringe) 4. Does the wetland meet all of the following criteria? 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: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks( depressions are usually <3ft diameter and less than 1 foot deep). NO r go to 5 YES — The wetland class is Slope y' 5. Is the wetland in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river? The flooding should occur at least once every two years, on the average, to answer "yes. " The wetland can contain depressions that are filled with water when the river is not flooding. NO - go to 6 YES The wetland class is Riverine Wetland Rating Form — western Washington 3 August 2004 6. Is the wetland in a topographic depression in which water ponds, or is saturated to the surface, at some time of the year. This means that any outlet, ifpresent, is higher than the interior of the wetland. NO —go to 7 YES — The wetland class is Depressional 7. Is the wetland located in a very flat area with no obvious depression and no stream or river running through it and providing water. The wetland 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 seems to be difficult to classify. 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. Sometimes we find characteristics of several different hydrogeomorphic classes within one wetland boundary. 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 recommended in the second column represents 10% or more of the total area of the wetland being rated. If the area of the second class is less than 10% classify 'the wetland using the first class. Slope + Riverine Riverine Slope + Depressional. Depressional Slope + Lake -fringe Lake -fringe Depressional + Riverine along stream within boundary Depressional Depressional + Lake -fringe Depressional Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE under wetlands with special characteristics If you are unable still to determine which of the above criteria apply to you` -wetland, or yola have more than 2 HGM classes within a wetland boundary, classify the wetland as,Depressional tor the rating. Wetland Rating Form, —western Washington 4 August 2004 I R R 1. Does the wetland have the potential to improve water quality? (seep. 52) R R 1.1 Area of surface depressions within the riverine wetland that can trap sediments during a flooding event: Depressions cover >3/4 area of wetland points = S Depressions cover > 112 area of wetland points = 4 Depressions present but cover < 1/2 area of wetland points = 2 No de ressions resent points z' 0 R R 1.2 Characteristics of the vegetation in the wetland: Forest or shrub > 2/3 the area of the wetland points = S Forest or shrub > 1/3 area of the wetland points = 6 Ungrazed, emergent plants > 2/3 area of wetland points Ungrazed emergent plants > 1/3 area of wetland points = 3 Forest, shrub, and ungrazed emergent c 1/3 area of wetland points = 0 R Add the points in the boxes above, R R 2. Does the wetland have the opportunity to improve water quality? (seep. 53) 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 of the following conditions provide the sources of pollutants. — Grazing in the wetland or within 150ft — Untreated stormwater discharges to wetland --- Tilled fields or orchards within 150 feet of wetland --- A stream or culvert discharges into wetland that drains developed areas, residential areas, farmed fields, roads, or clear-cut logging Residential, urban areas, golf courses are within 150 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 water above standards for water quality multiplier — Other VOs' `r multiplier is 2 NO multiplier is 1 R TOTAL - Water Quality Functions Multiply the score from R 1 by R 2 , Add score to table on .1 Comments Wetland Rating Form— western Washington 7 August 2004 R 3. Does the wetland have the potential to reduce flooding and erosion? R R 3.1 Characteristics of the overbank storage the wetland provides: Estimate the average width of the wetland perpendicular to the direction of the flow and the width of the stream or river channel (distance between banks). Calculate the ratio: (width of wetland)l(width of stream). If the ratio is more than 20 �_ points = 9 If the ratio is between 10 — 20 points = 6 If the ratio is 5- <10 points = 4 If the ratio is 1- <5 points = 2,,, If the ratio is < 1 R R 3.2 Characteristics of vegetation that slow down water velocities during floods; Treat large woody debris as `forest or shrub ". Choose the points appropriate for the best description. f•; Forest or shrub for >1/3 area OR Emergent plants > 2/3 area points =tf Forest or shrub for > 1/10 area OR Emergent plants > 1/3 area points = 4 Vegetation does not meet above criteria points = 0 R Add the points in the boxes above R R 4. Does the wetland have the opportunity to reduce flooding and erosion? (seep. 57) — Answer YES if the wetland 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. Note which of the following conditions apply. — There are human structures and activities downstream (roads, buildings, bridges, & ms) that can be damaged by flooding. — There are natural resources downstream (e.g. salmon redds) that can be multiplier damaged by flooding — Other (Answer NO if the major source of water to the wetland is controlled by a reservoir or the wetland is tidal fringe along the sides of a dike) DES multiplier is 2 NO multiplier is 1 K TOTAL - Hydrologic Functions Multiply the score from R 3 by R 4 Add score to table on p. 1 Comments Wetland Rating Form — westem Washington 8 August 2004 H 1. Does the wetland have the gotential to provide habitat for many species? H 1.1 Vegetation structure (seep. 72) Check the types of vegetation classes present (as defined by Cowardin) if the class covers more than 10% of the area of the wetland or % acre. quatic bed Emergent plants Scrub/shrub (areas where shrubs have >30% cover) Forested (areas where trees have >30% cover) Forested areas have 3 out of 5 strata (canopy, sub -canopy, shrubs, herbaceous, moss/ground-cover) Add the number of vegetation types that qualify. If you have: 4 types or more points = 4 3 types points = 2 2 types points — 0 1 tvne points � 0 H 1.2. Hydroneriods (seep. 73) Check the types of water regimes (hydroperiods) present within the wetland The water regime has to cover more than 10% of the wetland or % acre to count. (see text for descriptions of hydroperiodr) Permanently flooded or inundated 4 or more types present points = 3 Seasonally flooded or inundated 3 types present 'points = 2. ],Occasionally flooded or inundated 2 types present point 1 aturated only Permanently flowing stream or river in, or adjacent to, the wetland Seasonally flowing stream in, or adjacent to, the wetland Lake fringe wetland = 2 points Freshwater tidal wetland = 2 points H 1.3. Richness of Plant Specie (seep. 75) Count the number of plant species in the wetland that cover at least 10 fl . (different patches of the same species can be combined to meet the size threshold) You do not have to name the species. Do not include Eurasian Milfoil, reed canarygrass, purple loosestrife, Canadian Thistle If you counted: > 19 species points = 2 List species below f you want to: 5 - 19 species points `- < 5 species points Wetland Rating Form — western Washington 13 August 2004 H 1.4. Irate ersion of habitats (seep. 76) Decide from the diagrams below whether interspersion between types of vegetation .(described in H 1.1), or vegetation types and unvegetated areas (can incIude open water or mudflats) is high, medium, low, or none. A91EMb,, i ` F' & h a a h tl'i} •'m �I j�w- 4P',✓ v ��n �'Um•,,,y t �x one,19, oints Lowpoint•d- points [riparian braided channels] High = 3 points NOTE: If you have four or more vegetation types or three vegetation types and open water the rating is always "high". H 1.5. Special Habitat Features: (seep. 77) Check the habitat features that are present in the wetland. The number of checks is the number of points you put into the next column. Large, downed, woody debris within the wetland (>4in. diameter and 6 ft long). Standing snags (diameter at the bottom > 4 inches) in the wetland Undercut banks are present for at least 6.6 ft (2m) and/or overhanging vegetation extends at least 3.3 ft (lm) over a stream 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 At least 1/4 acre of thin -stemmed persistent vegetation or woody branches are present in areas that are permanently or seasonally inundated. (structures far egg -laying by amphib ians) Invasive plants cover less than 25% of the wetland area in each stratum of plants H 1. TOTAL Score - potential for providing habitat I Add the scores in the column above Comments Wetland Rating Form— western Washington 14 August 2004 H 2. Does the wetland have the opportunity to provide habitat for many species? H 2.1 Buffers (seep. 80) Choose the description that hest represents condition of buffer of wetland. The highest scoring criterion that applies to the wetland is to be used in the rating. See textfor definition of "undisturbed. } ---- 100 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% of circumference. No developed areas within undisturbed part of buffer. (relatively undisturbed also means no -grazing) Points = 5 — 100 rn (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 50% circumference. Points = 4 — 50 m (170#i) of relatively undisturbed vegetated areas, rocky areas, or open water >95% circumference. Points = 4 — 100 m (33Oft) of relatively undisturbed vegetated areas, rocky areas, or open water > 25% circumference,. Points = 3 — 50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, of open water for > 50% circumference. Points = 3 If buffer does not meet any of the criteria above --- No paved areas (except paved trails) or buildings within 25 m (80ft) of wetland > 95% circumference. Light to moderate grazing, or lawns are OY. Points = 2 — No paved areas or buildings within 50m of wetland for >50%o 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. tilled fields, paving, basalt bedrock extend to edge of wetland Points = 0. —% Buffer does not meet any of the criteria above. Points =1 H 2.2 Corridors and Connections (seep. 81) H 2.2.1 Is the wetland part of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 150 ft wide, has at least 30%Q cover of shrubs, forest or 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 used gravel roads, paved roads, are considered breaks in the corridor). go to H 2.2.2 YES = 4 points (go to H 2.3) Deand H 2.2.2 Is the wetland part of a relatively undistuunbroken vegetated corridor (either riparian or upland) that is at least 5Oft wide, has at least 30% cover of shrubs or forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a Lake -fringe wetland, if it does not have an undisturbed corridor as in the question above? YES = 2 points (go to H 2.3) O H 2.2.3 H 2.2.3 Is the wetland: within 5 mi (8km) of a brackish or salt water estuary OR within 3 mi of a large field or pasture (>40 acres) OR within I mi of a greater than 20 acres? (fESt 1 point NO = 0 points Wetland Elating Form— western Washington 15 August 2004 H 2.3 Near or adiacent to other Priority habitats listed by„WDFW (seep. 82) Which of the following priority habitats are within 330ft (100m) of the wetland? (s text for a more detailed description of these priority habitats) 2�4Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems_ which mutually influence each other. Aspen Stands: Pure or mixed stands of aspen greater than 0.8 ha (2 acres). Cliffs: Greater than 7.6 m (25 ft) high and occurring below 5000 ft. OId-growth forests: (Old -growth west of Cascade crest) Stands of at least 2 tree species, forming a multi -layered canopy with occasional small openings; with at least 20 trees/ha (8 trees/acre) > 81 cm (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. Prairies: Relatively undisturbed areas (as indicated by dominance of native plants) where grasses and/or forbs form the natural climax plant community. 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. Caves: A naturally occurring cavity, recess, void, or system of interconnected passages Oregon white Oak: Woodlands Stands of pure oak or oak/conifer associations where canopy coverage of the oak component of the stand is 25%. Urban Natural Open Space: A priority species resides within or is adjacent to the open space and uses it for breeding and/or regular feeding; and/or the open space functions as a corridor connecting other priority habitats, especially those that p would otherwise be isolated; and/or the open space is an isolated remnant of natural habitat larger than 4 ha (10 acres) and is surrounded by urban development. Estuary/Estuary-like: Deepwater tidal habitats and adjacent tidal wetlands, usually semi -enclosed by land but with open, partly obstructed or sporadic access to the open ocean, and in which ocean water is at least occasionally diluted by freshwater runoff from the land. The salinity may be periodically increased above that of the open ocean by evaporation. Along some low -energy coastlines there is appreciable dilution of sea water. Estuarine habitat extends upstream and landward to where ocean -derived salts measure less than 0.5ppt. during the period of average annual low flow. Includes both estuaries and lagoons. Marine/Estuarine Shorelines: Shorelines include the intertidal and subtidal zones of beaches, and may also include the backshore and adjacent components of the terrestrial landscape (e.g., cliffs, snags, mature trees, dunes, meadows) that are important to shoreline associated fish and wildlife and that contribute to shoreline function (e.g., sand/rock/log recruitment, nutrient contribution, erosion control). If wetland has 3 or more priority habitats = 4 points If wetland has 2 priority habitats = 3 points If wetland has 1 priority habitat =1 point No habitats = 0 points Wetland Rating Form — western Washington 16 August 2004 H 2.4 Wetland Landsca a (choose the one description of the landscape around the wetland that bestfits) (seep. 84) There are at least 3 other wetlands within 1/2 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 Iittle disturbance and there are 3 other lake - fringe wetlands within %2 mile points = 5 There are at least 3 other wetlands within 1/2 mile, BUT the connections between, are disturbed points The wetland is Lake -fringe on a lake with disturbance and there are 3 other lake - fringe wetland within 1/2 mile points = 3 There is at least 1 wetland within %2 mile. points = 2 There are no wetlands within 1/2 mile. points = 0 H 2. TOTAL Score - opportunity for providing habitat I Add the scores in the column above Total Score for Habitat Functions — add the points for H 1, H 2 and record the result on Wetland Rating Form — western Washington 17 August 2004 Appendix C GEQTECHNICAL REPORT GEOTECHNICAL REPORT SW 30h Street/Springbrook Creek Culvert Improvement Project HWA Project No. 2005.043-21 Prepared for R.W. Beck October 14, 2005 =11 HWA EOSCIENCES INC. HWA GEOSCI ENCES INC. Geotechnical Engineering • Hytlrgreolo,r October 14, 2005 H WA Pre j eet No. 2005-043-21 R.W. Seek, Inc. 100 Fourth Avenue, Suite 2500 Seattle, Washington 98154-1004 Attention: Mr. Michael S. Giseburt, P.E. Subject: GEQTECHN[CAL REPoRT SW 34`6 Street/Sprinabrook Creek Calvert Improvement Project City of Renton, Washington Dear Mr. Giseburt: Attached is our final geotechnical report for the SW 34`h Street/Springbrook Creek Culvert Improvement Project_ This report presents the results of our-geotechnical investigation and provides our recommendations for design and construction of the replacement culvert. The report also addresses review commentary and questions that were submitted to and discussed with Mr. Brian Hall of our office and me. We trust this final report satisfies your geotechnical design requirements, and appreciate the opportunity to provide geotechnical services on this project. However, if you have any additional questions or if we may be of further assistance, please contact us at your convenience. Sincerely, HWA GEOSCIENCES INC. Lorne Balanko, P.E. Geotechnical EnbrineenTrincipal 97'() - (A th Avenue W- Suite ?00 n.nu fm[i, WA 9806-5957 'Yet: 423.774-0106 Fax- 4.25,774-2714 ww,..h WRgeasciencei:coxa TABLE OF CONTENTS Page 1.0 IN'iRODUCTION...........................................................................................................1 1.1 GENERAL...................................................................................... ...............1 1.2 PROJECT UNDER -STANDING ............................................................................1 1.3 SCOPE OF SERVICES AND AUTIIORizAmN....................................................2 2.0 FIELD AND LABORATORY INVESTIGATIONS...............................................................2 2.1 FIELD INwsTIGATIDN...................................................................................2 2.2 LABORATORY TESTING.................................................................................3 3.0 GE.OLOGIC AND SUBSURFACE CONDITIONS................................................................3 3.1 SITE DESCRIPTION.........................................................................................3 3.2 GENERAL GEOLOGY ......................................................................................3 3.3 SOILS AND GROUND WATER.........................................................................4 4.0 CONCLUSIONS AND R.ECOM24ENDATIONS..................................................................4 4.1 GENERAL........................................................................................ 4 4.2 SEISMIC DESIGN RECONIMENDATIONS...........................................................6 4.2.1 Seismic Parameters ....... .................................... ................. ............ 6 4.2.2 Liquefaction Considerations..........................................................6 4.3 FOUNDATIONS...............................................................................................8 4.3.1 Three -sided Concrete Box Culvert ................................................8 4.3.2 Four-sided Concrete Box Culvert......... .........................................9 4.3.3 Estimated Settlement.....................................................................9 4.3.3.1 Seismic Considerations....................................................9 4-3.3.2 Static Considerations.— .................................................... 10 4.4 LATERAL EARTH CRESsUREs.........................................................................10 4.5 BACKFILL PLACEMENT AND C01APACTION....................................................1 1 4.6 EXCAVATION STABII. FY AND SHORING........................................................12 4.6.1 General..........................................................................................12 4.6.2 Open Excavations..........................................................................12 4.6.3 Shoring..........................................................................................13 4.7 WATER CONTROL..........................................................................................13 4.8 WET WEATHER EARTIhv'QRK........................................................................14 4.9 EROSION CONSIDERATIONS...........................................................................15 5.0 CONDITIONS AND LIMITATIONS ................... ............................................... I ...... ..,.....15 LIST OF FIGURES Figure 1. Vicinity Map Figure 2. Site and Exploration Plan Appendices Appendix A: Explorations Figure A-1. Legend of Terms and Symbols Used on Exploration Logs Figure A-2 and A-3. Logs of Borings BH-1 and BH-2 Appendix B: Laboratory Test Results Figure B-1 and B-2. Grain Size Distribution Test Result Figure B-3. Liquid Limit, Plastic Limit and Plasticity Index of Soils Figure B-4. One Dimensional Consolidation Properties of Soil GEOTECHNICAL REPORT SW 34"" STREET/SPRINGBROOK CREEK CULVERT IMTROVEMENT PROJECT CITY OF RENTON, WASHINGTON 1.0 INTRODUCTION 1.1 GENERAL This report presents the results of a geoteehnieal engineering study completed by HWA GeoSciences Inc. {HWA} for the planned replacement of the four existing, 72-inch, CMP culverts on Springbrook Creek at SW 34" Street in the City of Renton (City), Washington. The objective of our work was to investigate foundation conditions, and provide geotechnical recommendations for design and construction of the replacement culvert_ 1.2 PROJECT UNDERSTANDING Project location is shown on the Vicinity Map, Figure 1, and general site layout is shown on the Site and Exploration Plan, Figure 2. Based on discussions with you and information provided to date, we understand the City plans to remove the existing culverts and replace them with a three -sided concrete box culvert. At this time, we have been advised that two options exist for the replacement culvert; Option I consists of two side -by -side, 30-Moot width each, by 8-feet high, three - sided box sections. Option 2 consists of a single, 34-foot wide by 11-foot high box section. Although design details of the new culverts are not yet available, we understand that the streambed invert elevation within the new culvert will approximately match that of the existing culverts. After culvert replacement, the top of pavement will new to be raised about 1.5 and 2.7 feet to provide sufficient cover for Options 1 and 2, respectively. Several utilities are also shown on the plans, Existing 36-inch and 64-inch diameter storm sewers parallel the north side of the road and discharge into the creek on the west and east sides of the crossing, respectively, near the outer limits of the existing culverts. On the current survey plan, their discharge invert elevations are shown as 7.6 and 8.4 feet, respectively. An 8-inch PVC storm drain is shown to extend from the south curb line across the road to the north, roughly parallel to the eastern -most existing culvert. This may need to be removed and reconstructed depending on which option is selected. Based on the as -built plans, it appears the existing culverts were installed in late 1981 to early 1982. 1.3 SCOPE OF SERVICES AND AUTHORIZATION Our work was conducted in accordancewith our Geotechnical Work Scope and Cost, submitted to R. W. Beek on March 2, 2005. The work was authorized under a Subconsultant Agreement between the R. W. Beck and HWA, executed on or about April 18, 2005. Our scope of work completed for this project included performing two exploratory borings at the site, laboratory testing, engineering analysis based on the conditions observed in our explorations, and providing geotechnical engineering recommendations for the proposed replacement culvert. Because of the potential for contaminants in the near -surface soils at the crossing location, environmental sampling and testing of soil samples was also performed as part of the project scope. Results of this testing are, however, presented in a separate letter report. 2.0 FIELD AND LABORATORY INVESTIGATIONS 2.1 FIELD II`'VESTIGATION On April 18, 2005, HWA performed a subsurface exploration program that included drilling two exploratory borings (designated BH-I and BH-2) to depths of 61.5 feet each below existing grades. The drilling was subcontracted to Holocene Drilling of Fife, Washington. The borings were advanced using a truck -mounted drill rig employing a hollow -stem auger. The boring locations were determined approximately in the field by pacing and taping distances from existing site features. The borings were tied -in in the follow-up site survey and their locations are plotted on Figure 2. A geologist from HWA logged the explorations and recorded pertinent information including sample depths, stratigraphy, soil engineering characteristics, and ground water occurrence. Standard Penetration Test (SPT) sampling was performed using a 2-inch outside diameter split -spoon sampler and a I40-pound auto-ha>niner. During a SPT test, a sample is obtained by driving the sampler 18 inches into the soil with the hammer free -falling 30 inches. The number of blows required for each 6 inches of penetration is recorded. The Standard Penetration Resistance ("N-value") of the soil is calculated as the number of blows required for the final 12 inches of penetration. This resistance, or N-value, provides an indication of relative density of granular soils and the relative consistency of cohesive soils. Soil samples were classified in the field and representative portions placed in plastic bags. These soil samples were returned to our laboratory for further examination and testing. The sampled soils were classified in general accordance with the classification system described in Appendix A on Figure A-1- A key to the boring log symbols is also presented in Figure A -I . The boring logs are presented as Figures A-2 and A-3, and should be referenced for specific subsurface details at the boring locations. However, the SW 34th St.-Springbrook Ck Report Final (10-14-05).doc 2 HWA GeoSciences Inc. stratigraphic contacts shown on the logs represent the inferred boundaries between soil types, and may be gradational in nature and much less distinct than represented. 2.2 LABORAToRy TESTING Laboratory tests were conducted on selected samples obtained from the borings to characterize relevant engineering properties of the site soils. Laboratory tests included determination of in -situ moisture content, particle size analyses, Atterberg Limits of subsurface soil deposits, and a one-dimensional consolidation test on a representative sample of compressible soils encountered at depth. Moisture content test results are presented on the exploration logs, and particle size analyses are given in Figures B-1 and B-2, in Appendix B. Figure B-3 presents the result of an Atterberg Limit test on a fine- grained soil sample of the subsurface deposits. The consolidation test results are presented on Figure B-4. 3.0 GEOLOGIC AND SUBSURFACE CONDITIONS 3.1 SITE DESCRIPTION The project site is located on flat -lying land close to the south City limits. This segment of SW 34`h Street connects Oaksdale Avenue SW and Lind Avenue SW, and is immediately west of the East Valley Highway. The existing roadway is four -lane with curb and gutter and sidewalks on both sides. Pavement conditions appear to be relatively good at present. Springbrook Creek in this area flows in the base of a wide linear channel, likely widened many years ago as part of drainage improvement works by King County Drainage District No. 1. The vegetation surrounding the channel appears to be relatively sparse comprising grasses and weeds, with some shrubbery immediately adjacent to the outlet end of the crossing. Surrounding land use is mainly commercial and light industrial. 3.2 GENERAL GEOLOGY Geologic information for the site was obtained from the Geologic Map of the Renton Quadrangle, King County, Washington (Mullineaux, D. R., 1965). The map indicates that the area is generally underlain by lacustrine peat deposits over alluvium comprising unconsolidated sand, silt and clay, deposited by the White and Green Rivers before diversion of the White River to the south in 1906. Curvilinear channel gravels and abandoned channels also occur. Accordinb to the mapping, the peat is typically very soft, and may compress to 10% of original volume when loaded. SW 34th St.-Springhroek Ck Report Final {10-14-05.}.rdir j HWA Uec)5cim(;4 lne. 3.3 SOILS AND GROUND WATER The borings encountered approximately 4.5 feet of fill over organic silt (peat) to a depth of 9 to 9.5 feet, which in turn lie over alternating layers of sand and silt alluviums. The fill in BH-1, below a surface asphaltic concrete pavement layer of some 3 inches thickness, consisted mainly of medium dense, medium to coarse sandy, fine to coarse gravel pit -run material. This fill was observed to have been placed directly on the underlying organic silt/peat. In 1311-2, which was off the roadway surface in the shoulder area, sod over loose, fine to medium, sand fill was encountered. In this location the organic silt/peat was interbedded with thin layers of silt and fine sand alluvium. The alluvium underlying the upper peat is variable. The alluvial layers encountered generally consisted of loose and medium dense fine to medium sand, and loose to medium dense silty sand, soft sandy silt; and very soft gray silt. At depths of about 32 feet 13H-1 and 23 feet in BH-2, shell fragments suggest the presence of estuarine deposits. These estuarine deposits comprise loose to very loose/soft to very soft fine sandy silt and plastic silt materials. In some cases, the silt was so soft that the SPT sampler penetrated under its own weight. In view of our field observations and test results, it is believed that the subsurface soils at the site are normally consolidated. Hence, any net increase in loading of these deposits, as a consequence of culvert reconstruction, will result in consolidation of the underlying soils and settlement. Immediately after drilling, ground water was observed at a depth of about 10 feet in BH- 1, and was not recorded in BH-2. However, observations of water levels during drilling can be misleading. Actual ground water levels are often higher than those observed in a boring, because borings are typically open only for a short time, and the auger used to advance the boring can smear the side of the hole inhibiting seepage. The ground water elevation reported on the boring log is for the specific date and location indicated and, therefore, may not be indicative of other times and/or locations. We anticipate that ground water elevations will vary depending on the season, local subsurface conditions, and creek water level, which was around the mid -depth of the culverts, and would correspond roughly with about El. 11 feet, or some 7 feet below road surface at the time of the investigation. For design and construction purposes, the prevailing ground water level should be taken to be the same as the creek level at any given point in time. 4.0 CONCLUSIONS AND RECOMMENDATIONS 4.1 GENERAL The investigation encountered about 4.5 feet of fill over soft organic silt/peat extending to about EI. 8.5 to 9 feet, over alternating layers of very loose ranging to medium dense sand and very soft to soft silt alluvium. Very soft estuarine deposits were noted at depth below SW 34th St.-Spring6rnnk Ck Repud Final (10-14-05).doc 4 H WA GeoSciences Inc. the alluvium and extend to the full penetration depth of the exploration borings. The sand alluvium is both variable and potentially liquefiable. The deep silt alluvium and estuarine silt is soft to very soft, of very low strength and is compressible under any increased loading that might be generated by placement of additional fill or heavy structures above the material. Based on our investigation, the following culvert solutions have been considered and evaluated in this report: • Three -sided Concrete Box Culvert; Because of the potentially liquefiable sandy soils at and below the likely founding elevation, such a culvert should ideally be founded on pile foundations to prevent potential future damage. However, piles are not considered cost-effective for this site due the substantial depths of liquefiable soils and the lack of a suitable bearing zone at shallow depth below the site. The negative skin friction and downdrag that would be potentially generated during a seismic event would necessitate extremely long piles to provide for even modest load capacity. Accordingly, if a three -sided box culvert section is employed, it will need to be founded on footings supported in turn on a prepared pad. The pad will need to comprise compacted granular or control density fill (CDF), which we prefer for this application. If this approach is adopted, however, some damage following a design seismic event, due to differential settlement of the culvert sections, should be anticipated and potential repair costs incorporated into long-range maintenance considerations for the facility. • Four-sided Concrete Box Culvert. Such a culvert structure will effectively incoporate a mat foundation and will be able to accommodate long-term settlement and more readily resist liquefaction impacts during a major seismic event. Additionally, given the reduced bearing pressure contributed by this type of structure, lesser base preparation will be required. The following construction aspects will play a significant role in the culvert construction, if shallow foundations are provided: Excavation Support: Excavation is required through fill and soft organic soils in close proximity to utilities. Measures are required to support the excavation, and particularly limit disturbance to the adjoining utilities. Water: Ground and surface runoff water control will play a large role during preparation of the foundation. For construction of footings within open excavations, bypass pumping of creek flows will be required. Dewatering is also required to lower the ground water level so that the excavation and subgrade preparation can be performed under relatively dry conditions. However, we anticipate that if the ground water is lowered more than SW 34th St.-Springbrook Ck Reym Final( I O-14-05).doc: 5 HWA GeoSciences Inc. about 7 to 10 feet below current elevations for significant periods, settlement of the existing sewers and nearby facilities could occur. 4.2 SEIsmic DESIGN RECOMMENDATIONS 4.2.1 Seismic Parameters Buried culverts are typically not required to be designed to seismic design standards (AASHTO, 1996). However, it is possible that consideration might be given to treatment of the replacement box section as a bridge and seismic design parameters for the site are, therefore, provided herein. Per AASHTO design guidelines (AASHTO, 1996), the acceleration coefficient, A, applicable for design purposes is that which is generated by an earthquake.with a 10 percent probability of exceedance in a 50 year period, or a 1 in 475 year return interval. Data available for the USGS through their Earthquake Hazards Program Website, indicates that the appropriate A value for this site is 0.322g. Our investigation observations indicate that the site can be characterized by a Type IV soil profile and we recommend a Site Coefficient (S) of 2.0 for this project. 4.2.2 Liquefaction Considerations Our liquefaction analyses, based on cyclic stress ratio concepts developed by Seed and Idriss (Seed, H.B,, Idriss, I.M., 1982), indicate that a substantial zone of liquefaction will occur in the site soils below about El. 9 feet at the location of both borings. The combined thickness of anticipated liquefiable materials, however, ranges widely from about 24 feet at BH-1 to 6 feet at BH-2. In the latter case, substantially lesser thickness of clean sand was observed in this boring on the west side of the crossing. Only the silt layers are considered to be unlikely to liquefy during a design (i.e. 1 in 475 year) seismic event, due either to their very high fines content and/or inherent plasticity characteristics. Based on information available from the as -built and current survey plans, it is anticipated that the new culvert will have an invert level of the order of El. 8 feet. The foundation system may be 1.5 to 2 feet lower, i.e. El. 6.5 to 6 feet, thereby, being within the top of the potentially liquefiable zone. Empirical relationships suggest that volumetric strains associated with soil liquefaction at this site may be on the order of 1.5 to 3.5 percent, dependent on variability of soil conditions. Conservatively assuming that soil confinement at depth will limit lateral straining, the estimated vertical displacements associated with liquefaction may range from as little as about 1 inch to upwards of 10 inches below the culvert -crossing site, assuming the best and worst case situations. However, it is our view that the liquefaction -induced settlements are likely to be significantly less than the upper bound SW 34th St.-Sprirtghrook Ck Report Final (14-14-45).doc 6 HWA Geosciences Inc. estimate, and the differential settlements, as suggested by conditions at the borings, are also likely to be significantly less. We are of the opinion that liquefaction -induced settlement of the culvert would entail some subsidence of the culvert invert profile with probable sagging introduced beneath the center of the embankment, and some rotation in the direction of BH-1 to the east. This could be accompanied by cracking of the culvert section, which we anticipate would be greater for the three -sided box alternative, but loss of hydraulic serviceability due to collapse would not be expected. While settlements at the culvert location may occur as a consequence of liquefaction, it is probable that adjoining soils are similar to those noted at the boring locations, and will likely also experience some degree of settlement (i.e. more or less than the culvert location). Thus, settlement won't be isolated to the culvert crossing itself and its impact will tend to be less pronounced overall. Lateral spreading of the soils comprising the creek banks is probable during the design seismic event, inasmuch as the top of the liquefiable zone is near .or within the base of the channel banks. However, at the crossing location, the roadway embankment and culvert/bridge will locally buttress the banks against sliding/spreading. Design forces that will be transferred to the structure can be determined from the lateral earth pressure recommendations provided in Section 4.4 of this report. Mitigation measures to deal with liquefaction issues are typically expensive and may not be particularly suited to this site. For example, stone columns are commonly employed for ground densification purposes and relief of excess hydrostatic pressures that occur during seismic events, but would have to be installed in the creek channel to be effective. Typically, stone column installation can generate substantial sediment that would have to be removed from the treated area and not be allowed to enter the creek, Prefabricated wick drains might also be employed to reduce excess hydrostatic pressures, but would have to be installed on a very tight spacing to be effective. Since these installations would also allow movement of water in the reverse direction, creek flow directly into subsurface soil units may be an issue that would need to be evaluated with regard to potential adverse environmental impacts. Driving of untreated green timber piles on close spacing is another method of ground densification that is commonly employed. In this case, ground treatment work would again have to extend into the creek. Lastly, the replacement culvert might be supported on piles that would be capable of resisting downdrag effects associated with soil liquefaction and settlement. The downdrag effects result in a downward friction force on the piles as the soils around the piles settle relative to the piles. Therefore, the pile system needs to be capable of supporting the design load as well as downdrag forces, Consequently these piles would have to be very long and costly. In addition. deep exploration work would be necessary to evaluate their design requirements. HWA has recently conducted geotechnicat investigations for two culverts upstream on 5pringbrook Creek for the City of Kent, The culverts are located at South 192nd Street SW 34th St.-Sprinbbrook Ck Report Final (14-14-05).doc 7 HWA GcoSciences inc- (CMP culvert with span of about 12 feet), and South 188th Street (CMP culvert with span of about 22 feet). At both locations, potentially liquefiable sands were also encountered below the anticipated founding elevation for shallow foundations. The South 192nd culvert has been constructed and is supported on a mat of Controlled Density Fill (CDF). Since completion of our report, the City has decided not to proceed with replacement of the South 188th Street culvert. However, prior to that they had decided to found the culvert on a mat of CDF, similar to that for the 192nd Street culvert, because the cost of piling would have been excessive. For both culverts, it is understood that during a major earthquake, the culverts could settle/tilt and they may require repair to maintain the flow opening but that eliminating this risk by constructing the culverts on piles was not worth the additional cost. 4.3 FouNDATrONS 4.3.1 Three -sided Concrete Box Culvert The proposed new culvert is anticipated to be constructed on the same alignment as the existing 4 CMP culverts, effectively straddling their current location. The existing storm drainage facilities are likely to constrain the outlet location somewhat, unless their outlets are also altered. Old and new culvert invert elevations are anticipated to be similar. Existing organic silt/peat materials, and possibly old backfill materials, are anticipated to be present near or somewhat above the proposed footing level for the new culvert. If present, however, at footing level, we recommend that these materials be excavated from below the culvert footprint to expose the native sand deposit below. The excavated material should be replaced with crushed rock fill, conforming to the requirements outlined in Section 9-03.9 (1) Ballast, of the 2004 WSDOT Standard Specifications, or controlled density fill (CDF). A foundation material replacement thickness of 2 feet is recommended to provide for uniform foundation support and load transfer to underlying native soils. If crushed rock is used, the replacement fill should extend to 3 feet on either side of the culvert and the base and sides of the excavation should be covered with a woven geotextile. The geotextile should conform to the requirements outlined in Section 9-33.2, Geotextile Properties, Table 3, Separation, of the 2004 WSDOT Standard Specifications. The crushed rock should be lightly compacted by static rolling with a small drum compactor, but, rolling should be discontinued if pumping of the pad and underlying subgrade becomes apparent. If CDF is used, the replacement fill should extend to.2 feet on both sides of the culvert footing and a woven geotextile is not required because of the compressive strength of the CDF. We prefer CDF since its use prevents disturbance to the supporting subgrade soils beneath the new culvert and its foundation system. However, with care, either approach will result in suitable support. Regardless of preparation methodology, the footings should be proportioned for an allowable bearing SW 34Eh St.-Springbmok Gk Report Final (10-1445).doc 8 HWA GwSciences Inc. pressure not exceeding 2000 pounds per square foot (psf). However, regardless of footing pressure considerations, the minimum recommended footing width is 24 inches. 4.3.2 Four-sided Concrete Box Culvert A 4-sided box culvert has some advantages over a three -sided concrete box culvert in that the culvert weight and dead and live loads acting upon it can be supported over the base slab which precludes construction of wide footings to support loads generated on the culvert legs. Moreover, a box culvert structure is more rigid than the three -sided section and differential settlements due to static loading and, more significantly, seismically induced liquefaction movements can be more readily accommodated. However, foundation edge pressures associated with the four-sided box may be greater than that contributed by individual footings and this could give rise to the potential for greater localized settlements. Base preparation for the four-sided box should be similar to that for the three -sided structure, but the depth of sub -excavation may be reduced to that which will accommodate construction equipment and personnel without disturbance and/or deflection of the underlying foundation soil. -We recommend that the minimum sub - excavation depth should be at least 12 inches, and CDF is again preferred for the pad preparation material, particularly in light of reduced thickness. 4.3.3 Estimated Settlement 4.3.3.1 Seismic Considerations As indicated in Section 4.2.2, our borings suggest that the proposed footing elevation for the new box culvert will be immediately above liquefiable sand, which will be incapable of supporting much, if any, foundation loading during a design seismic event. Sub - excavation and placement of a crushed rock fill or CDF mat for foundation support will mitigate the effects of liquefaction to some degree, by acting as somewhat of a raft, but will not prevent foundation settlement from occurring. Accordingly, if the structure is to be designed to remain completely serviceable and largely undamaged after a design seismic event, it would need to be founded on piles. As discussed previously, a deep pile system would need to be designed for seismic considerations, will be inefficient due to the large downdrag loading that it wiI] have to carry, and is not recommended in the absence of further deep exploration. Even if further deep exploration is done, it is highly likely that the required depth and/or size of piles to support the load and downdrag would snake a pipe system not cost effective. Rather, we recommend selection of the four-sided box alternative, if reduced deformation and damage is to be achieved. Alternatively, if a greater risk of potential deformation damage is considered acceptable a three -sided box founded on spread footings is feasible. SW Nth&.-SpringbrookCk Report Nnal(t0-i4-05) doc 9 1FWA GeoSciences Inc. It is our opinion that either culvert option, supported directly on a prepared pad., provides a reasonable level of.risk for the type of facility under consideration. There may be some loss of serviceability (freeboard) or need for structural repairs in the event of the design earthquake occurrence; however, it is also possible that this could conceivably not happen during the design life of the facility. 4.3.3.2 Static Considerations For static conditions and the proposed increases in road grades associated with either of the culvertreplacement options, long-term settlements are to be anticipated. In consideration of the proposed grade changes, settlements are estimated to be of the order of 2 inches in the center of the loaded area, and differential settlements between center and ends of the culverts may be 50 percent of the total (or 1 inch). Option 2 with the single replacement culvert would be anticipated to settle somewhat less than the twin culvert option, as the loading conditions appear to result in lesser influence on the highly compressible deposits at depth. In respect to localized loading effects under the footings, the 4-sided box culvert is anticipated to settle less than the isolated strip footing foundation alternative. Settlements associated with structural loading of the foundation soils at shallow depths will be relatively quick, as it will be predominantly elastic in nature and largely completed on backfilling of the culverts and completion of the roadway, whereas the influence of grade raising operations will induce settlements in the deep compressible layers and will be long-term in nature. The settlement estimates assume that net loading due to the new structure and surrounding backfill will be somewhat greater than current conditions, consistent with the two replacement options indicated to us by R.W. Beck. It is to be noted that our settlement estimates have also been based on the premise that all near surface organic silt has been removed from below the loaded area, and would be most particularly applicable to the culvert replacement area. If road grades are raised in areas which remain underlain by compressible organic layers settlements could be substantially greater due to compression of these near surface layers. 4.4 LATERAL EARTH PRESSURES For determination of lateral earth pressure design parameters, we have assumed that the existing embankment fill and native soils will be removed and replaced with a suitable granular backfill. We have further assumed that the backfill adjoining the walls of the culvert will be placed to a horizontal condition at its surface and is compacted to the requirements provided for in Section 4.5. On the basis of an assumed wet unit weight of 125 pef for the backfill and a friction angle of not Iess than 35 degrees, and seismic parameters provided in Section 4.2.1, we recommend the following equivalent fluid unit weights for design purposes. SW 34th St.-Springbrook Ck Report Final (I0-14-05).doc 10 HWA GeoSuienu tns Inc_ Loading Condition Equivalent Fluid Unit Weight (pcf) Active — Static (KA) 35 Active — Seismic (KAO 40 At Rest — Static (KO) 55 At Rest — Seismic (KOJ 80 Passive - Static (Kp) 460 Passive - Seismic (KPj 435 The foregoing parameters are based on fully -drained conditions. As ground water at the culvert location is expected to fluctuate in response to the stream level, water pressures are likely to act on portions of the structural elements. Accordingly, the buoyant unit weight of the soil will apply below the water table and full hydrostatic pressure must be added to that section of structure below the water table. To determine the appropriate equivalent buoyant fluid unit weight for the above cases, multiply the above values by the ratio of buoyant to drained unit weights (i.e. 0,50 in this case) and add 62.4 pc£ As indicated above, the lateral earth pressure parameters apply only to horizontal backfill conditions, and will have to be increased or decreased for sloping backfill conditions. It is also to be noted that the parameters are unfactored, and a suitable factor of safety should be applied to the passive earth pressure values for determination of restraint forces. In this latter regard, an allowable (FS = 1.5) coefficient of sliding resistance equal to 0.45 is recommend between footings and underlying granular soils for determination of sliding resistance. 4.5 BACKFILL PLACEMENT AND COMPACTION Crushed rock backfill should consist of materials meeting the requirements for Crushed Surfacing Base Course, as described in Section 9-03.9(3) of the 2004 WSDOT Standard Specifications for Road, Bridge, and funicipal Construction. Materials used to backfill the culvert excavation should consist of Gravel Backfill for Walls, as described in Section 9-03.12(2) of the 2004 WSDOT Standard Specifications. During placement of the initial lifts, the backfill material should not be bulldozed into the excavation or dropped directly on the structure. Furthermore, heavy vibratory equipment should not be permitted to operate directly over the structure until at least 2 feet (and possibly more, depending on the weight of the compactor) of material is present above the crown of the culvert section, unless otherwise approved by the structural engineer. SW 34th St.-Springheook Ck Report Final (10-14-05 ).doc l l 14WA GeoSciences Inc. In order to minimize subsequent settlement of the excavation backfill, new pavements, and utilities, we recommended that backfill soils be placed and compacted to the standards outlined in Section 2-03.3(14) C, Method B, 2004 WSDOT Standard Specifications. The procedure to achieve proper density of compacted fill depends on the size and type of compaction equipment, the number of passes, thickness of the layer being compacted, and soil moisture -density properties, If access or load considerations restrict the use of heavy equipment, smaller equipment can be used, but the soil must be placed in thin enough lifts to achieve the required compaction. 4.6 EXCAVATION STABILITY AND SHORING 4.6.1 General Excavation and construction of the replacement culvert must be performed in a manner which will not adversely impact existing utilities. Temporary support and protection of the existing storm sewers and any other utility lines must be provided and maintained during construction. Alternatively, temporary relocation of utilities may be required during the period of construction and embankment reinstatement. We anticipate that excavation can be accomplished with conventional equipment such as backhoes and traekhoes. The excavation is anticipated to have a maximum depth on the order of 12 feet, but could be deeper if deleterious subgrade materials are encountered at intended foundation levels. Maintenance of safe working conditions, including temporary excavation stability, is the responsibility of the contractor. All temporary excavation in -excess of 4 feet in depth must be sloped in accordance with Part N of WAC (Washington Administrative Code) 296-155, or be shored. The near surface materials encountered generally classifies as Type C soil, for which WAC requires that unsupported excavation must be inclined no steeper than 1.511:1V, but flatter slopes are likely necessary because of water seepage. Alternatively, the excavation should be shored. 4.6.2 Open Excavations Because of the nature of the soils encountered in the exploratory borings, we recommend that the sides of the excavation be supported using temporary sheet piles. Open excavations may be feasible if the existing storm sewer services are protected. However, if a temporary open excavation is undertaken, we recommend that it should be sloped at no steeper than 2H:1 V after local dewatering to at least 3 feet below invert, but existing soil conditions may dictate even flatter slope angles. The recommended slopes are less SW 34th St.-Springbrook Ck Report Final (10-14-05).doc 12 HWA GcoSdences Inc. steep than recommended by WAC, and should be monitored and slope angles adjusted in the field based on local subsurface conditions and the contractor's methods. ' With time and the occurrence of seepage andlor precipitation, the stability of temporary unsupported cut slopes may be significantly reduced. Therefore, all -temporary slopes should be protected from erosion by installing a surface water diversion ditch or berm at the top of the slope and by covering the cut face with well -anchored plastic sheets. 4.6.3 Shoring If shoring is required, we recommend that sheet piling be driven as temporary shoring along both sides of the excavation. For cantilever support, it will be necessary to advance the sheet piles below the level of the excavation for the new culvert at least equivalent to the height of soil being supported at any given point. Accordingly, this will involve driving the sheet piles from 15 to 20 feet below the base of the new excavation. The sheet piling should extend longitudinally a distance equal to the excavation depth beyond the ends of the excavation necessary for installation of the new culvert. We recommend that the design of the temporary shoring should be based on a uniform lateral pressure distribution of 25H psf (where H is the depth of the excavation in feet). This pressure does not include any surcharges due to equipment or materials near the shoring and assumes that water pressures do not act above the base of the excavation. Dewatering may be necessary to achieve this ground water condition. Alternatively, shoring could be accomplished with soldier piles and lagging. Soldier piles generally consist of steel 'H' sections embedded in predrilled vertical concrete -filled holes installed along the length of the proposed excavation. As the excavation proceeds from the top down, wooden or steel -plate lagging is placed to retain the soil between the soldier piles. 4.7 WATER CONTROL The contractor should be responsible for control of ground and surface water. Construction of either of the culvert alternatives on shallow foundations will require suitable temporary diversion of the creek, to allow construction largely in the dry. Construction dewatering is important because it will be very difficult to maintain stable slopes, prepare subgrade, evaluate subsurface conditions, and construct structures in the wet. In addition, upward seepage into the excavation base can cause sand boils and/or heaving. Because of these adverse impacts, dewatering should be accomplished so that culvert construction can be completed in the dry. We recommend that the proposed excavation be dewatered to maintain the ground water level at least 3 feet below the base of the excavation, and dewatering measures should be implemented before excavation to final subgrade level begins. Dewatering should continue until the culvert has been placed SW 34th St.-Springbrook Ck Report Final 0 0- 1 4-05).&,u 13 HWA CseoSciences Inc. and backfilled, and is capable of resisting hydrostatic forces. Disposal of water will be a consideration that will have to be suitably resolved with environmental and fisheries agencies having jurisdiction. We anticipate that wells or well points will be required, but this is dependent on the depth of the excavation, volume of ground water seepage, and potential presence of boiling or quick conditions in the excavation base. The latter condition will need to be evaluated at the time the excavation is undertaken, as it will dependent on the shoring methods and dewatering measures implemented by the contractor. Construction dewatering requirements will also depend on the time of year, creek level, recent rainfall and other factors. For this reason, construction should be performed during the dry summer season, subject to fisheries considerations and regulations. The contractor should be made aware that if the ground water is lowered by more than about 7 to 10 feet below current elevations for significant periods, settlement of nearby facilities could occur. We recommend that settlement of nearby facilities be monitored using optical survey methods during the period of any dewatering. Additionally, it is recommended that ground water monitoring wells or piezometers be installed between the works and adjoining critical facilities to permit observation of ground water levels. Should potentially adverse drawdown and/or settlements become apparent, it may be necessary to suspend the dewatering operations until mitigation measures, such as re- injection wells are designed and implemented. 4.8 WET WEATHER EARTHwoRK Existing site soils are moisture sensitive to varying degrees, and may be difficult to handle or traverse with construction equipment during periods of wet weather. Therefore, general recommendations relative to earthwork performed in wet weather or in wet conditions are presented below. These recommendations should be incorporated into the contract specifications and should be required when earthwork is performed in wet conditions: i} Site stripping and fill placement should be accomplished in small sections to minimize exposure to wet weather. Excavation or removal of unsuitable soil should be followed promptly by placement and compaction of a suitable thickness of clean structural fill. The size and type of construction equipment used may have to be limited to prevent soil disturbance. 2) Material used as structural fill should consist of clean granular soil, of which not more than 5% passes the U.S. Standard No. 200 sieve, based on wet sieving the fraction passing the %-inch sieve. The fine-grained portion of structural fill soils should be non -plastic. SW 34th St.-Springhrook Ck Repod Final (10-14-05).doc 14 iIWA GeoSciences Inc. 3). No soil should be left uncompacted so it can absorb water. Stockpiles of excavated soil should either be shaped and the surface compacted, or be covered with plastic sheets. Soils that become too wet should be removed and ' replaced with clean granular materials. 4) Excavation and placement of fill should be monitored by someone experienced in wet weather earthwork to determine that the work is being accomplished in accordance with the project specifications and the recommendations contained herein. 4.9 EROSION CONSIDERATIONS Erosion can be minimized by careful grading practices, the appropriate use of silt fences and/or straw bails and by implementing the recommendations in the Wet Weather Earthwork section of this report. Surface runoff control during construction should be the responsibility of the contractor, and should be treated prior to discharge to a permanent discharge system such as a storm sewer, so as to comply with State water quality standards. All collected water should be directed to a permanent discharge system, such as a storm sewer. Permanent control of surface water should be incorporated in the final grading design. Water should not be allowed to pond immediately adjacent to foundations or paved areas. Grading measures, slope protection, ditching, sumps, dewatering, and other measures should be employed as necessary to permit proper completion of the work. 5.0 CONDITIONS AND LIMITATIONS We have prepared this report for use by R-W. Beek and the City of Renton for design of a portion of this project. This report should be provided in its entirety to prospective contractors forbidding or estimating purposes; however, the conclusions and interpretations presented should.not be construed as a warranty of the subsurface conditions. Experience has shown that subsurface soil and ground water conditions can vary significantly over small distances. Inconsistent conditions can occur between explorations and may not be detected by a geotechrucal study. If, during future site operations, subsurface conditions are encountered which vary appreciably from those described herein, HWA should be notified for a review of the recommendations of this report, and provide revisions, if necessary. We recommend that HWA be retained to review the plans and specifications and to monitor the geoteehnical aspects of construction, particularly construction dewatering, excavation, subgrade preparation, bedding and backfll placement and compaction. SW34thSt. -SpringbrnokCkRcpor4Final (10-14-05).doc 15 HWA GeoSciwees Inc. HWA does not practice or consult in the field of safety engineering. We do not direct the contractor's operations, and we cannot be responsible for the safety of personnel other than our own on the site; the safety of others is the responsibility of the contractor. The contractor should notify the owner if he considers any of the recommended actions presented herein unsafe. We appreciate this opportunity to be of service. Sincerely, HWA GEoSciENcEs INc. EXI'1R E5 Qg4 f Lorne Balanko, P.E. Principal Brian E. Hall, P.E. Vice President SW 341h SL.-Springbrmk Ck Report Final (10-14-05).doe 16 HWA GeoSciences Inc. 71— M., Xf VICINITY MAP DRAWN BY KS SW 34TH STREET CULVERT cHj:cxrn BY fmGEoscmNcBlNC SPMNGBROOK CREEK PATE PRO.ECT No RENTON, WASHINGTON 5.17.05 2005-043 10' 20' 40' LEGENd �H-1 BOREHOLE DESIGNATION AND APPROMMATE LOCATION (7 ,u TFl t rl \77 1.46 AiL V -TT I BM-1 TT -BH-2 v f.11, TLI: SW 34TH STREET CULVERT SPRINGBROOK CREEK Ll W&GMSM4M INC D;=mTnN WASHINGTON SfM AND ExpLORA-TTON . PLAN 5.17.05 1 2005-M3 APPENDIX A FIELD EXPLORATIONS RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE CONESIONI-ESS SOILS COHESIVE SOILS Approximate Density N Obws.4q App�Demrt�ryt9t) Conslstancy N (biovv U�6th Shear Relative VeryLoose 0 to 4 0 - 15 Very Soft 0 to 2 .250 Loose 4 to 10 15 - 35 Soft 2 to 4 250 • 50D Medium Dense 10 to 30 35 85 Medium Stiff 4 is 6 Soo 1000 Donee 30 to SD 65 85 Stiff B is 15 1000 - 2000 Very Dense over50 85 - 100 Very -Stiff 15 to 30 2000 4000 Hard over 30 >4000 USCS SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP DESCRIPTIONS Gravel and GW Weraded GRAVEL 11$ Coarse Clean Gravel • ` Grained Grlly Stills ave (little or no fines) o (7 GP Poorly grodad GRAVEL soils l� More than 50%ofCoarse GravelWitil o GM Silty GRAVEL Fraction Retained Fines (appreciable on No. 4 Sieve amourd of fines) GC clayey GRAVEL Sand and Clean Sand SW Wel4tadsd SAND " Sandy Solis (little or no lines) More than Sp Poody-gradadSAND 50% Retained Sand with . 'SM Silty SAND on No. 50% or More 20D Sieve of Coarse Fines (appreciable Fraction Passing Size amount of fines) SC Clayey SAND No 4 Sieve { ! ML SILT Fine Slit III Uquid Limit Grained and CL Lan CLAY SOIk Clay Less than 50% OL Organic SILTKkganic CLAY M H Elastic SILT W%or More SIR Liquid Limit Passing anti 50%orMore CH Fat CLAY No, 200 Sieve clay Size OH Organic SILT1Organk CLAY Highly Organic Soils PT PEAT COMPONENT DEFINITIONS COMPONENT SIZE RANGE Boulders Larger than 121n Cobbles 3 in to 12 in Gravel 3 In W No 4 (4.5mm) Coarse gravel 3 in W 3l4 in Fine gravel 314 In to No 4 (4,5mm) Sand No, 4 (4.5 mrn) to No. 2D0 (0,074 mm) Coarse sand No. 4 (4.5 ram) to No. 10 (2.0 mm) µedium sand No. 10 (2.0 mm) to No. 40 40-42 mm) Fine sand No. 40 (0.42 mm) to 140. 200 (0.074 mm) Sire and Clay Smaller than No. 200 (0.074mm) TEST SYMBOLS %F Percent Fines AL Atletberg Lkrfts: PL = Plastic Umit LL s Liquid Limit CBR Califomia Searing Ratio CN Consollda*irf DO Dry Density (Pof) DS Direct Shear GS Grain Size Distribution K Permeatillity MD MoistorelDensily Rolationf;Np (Proctor) MR Resilient Modal s PID Phdoionlzabon Device Reading PP Pocket Penebometar Approx, Compresshe Strength (M SG Specific Gravity TIC Trianal Compression TV Torvane Approx. Shear Strength (tsf) UC Unconfined Compression SAMPLE TYPE SYMBOLS ® 2,0" OD Spill Spoon (SPT) (140 lb. hammer with 30 In, drop) IShelbyTuhe h 4" 3.11OD Split Spoon with Brass Rings (1 1 1 Small Bag Sample Large Sag (Bulk) Sample Core Run Non-standard PenetraW Test (3,0' OD split spoon) GROUNDWATER SYMBOLS Groundwater Level (measured at time of drilling) T Groundwater Level (measured in well or open hole after water level stabiUad) COMPONENT PROPORTIONS PROPORTION RANGE DESCRIPTIVE TERMS < 5% Clean 5. 12% Slightly (Clayey, Silty, Sarldy) 12. 30% Clayey. Silty, Sandy. Gravelly 30 - 50% Very (Clayey, Silty, Sandy, Gravelly) Components are arranged in order of increasing quantities. NOTES' Soil da siticatloms presented on exploration logs are based on visual and kaboralory observation. Sod descriptions are presented in the following general order. Oerrsilykansisferlcy cold; modifier (if any) GROUP NAM& adddlom 1c group name (of any), Musfum eonlBrft. Proipaton,gradation, and angularity ofconsf&mnls,addlfhxm(comments. (GEOLOGIC fNTERPRI TATION) Please refer to the discussion in the report text as well as the exploration logs for a more complete description of subsurfeoe conditions, ULT, I HWAGEOSCIENCES INC. SW 34TH STREET CULVERT SPRINGBROOK CREEK RENTON, WASHINGTON MOISTURE CONTENT DRY Absence o1 moisture, dusty, dry to the touch. MOIST Damp but no visible water. WET Visible free water, usually sog is below watertable. LEGEND OF TERMS AND SYMBOLS USED ON EXPLORATION LOGS PROJECT NO.: 2005-043 FIGURE: A-1 LEGEND 2005043.GPd Sr19105 DRILLING COMPANY: Holocene Driiling SURFACE ELEVATION: 18,00 t lest DATE STARTED: 411&20D5 DRILLING METHOD: HSA; Mobbe M1 DATE CCIMPL.ETED: 4118ft005 SAMPLING METHOD: SPT Nd Aulohammer LOGGED BY: B. Thurber LOCATION: See Site E Explorallan Plan, Figure 2 O o 5 1 10 1 15 1 20 1 25 DESCRIPTION TMedium dense. brown, slightly silly, medium to coarsesandy, fine to coarse GRAVEL, moist, Gravel mostly 2 inches, (PITRUN FILL) Q 0a OL Soft, dark brown. organic SILT, motel• — Soft, damn brown and light gray, fibrous organic SILT, moist. Softyg_rayplastic SiL7�moist. — — — — — — — — — — - ML - OL Soft, dark brown and light brown, organic SILT, moist- SP Loose. gray slightly silty, fine SAND, wet. Scattered fibrous SM organics. (ALLUVIVAq 5P------------------------ Loose grading to very loose, black, clean, fine to medium SAND, wet. Moony black grains, some red. 1-5 inch Lam: of purple -brown SILT at 13 feet, with a few fibrous organics. Very loose, darkgrey, sitlyfine SAND. wet------ SM SP----------•------------ SM Loose, black, clean, fine to medium SANE) with beds of dark gray, sltty fine SAND, wet, Finely bedded, SM---------------------- Loose, grey -brown, fine sandy SILT and silty fine SAND, with two beds of black, clean, fine to medium SAND, wet. — — — ML Lcase, gr%rybrovvn, SILT, wet. Mon-plaslic. ----------------------- SP F Z -K w e w� z to to a 0 0 S-1 10-12-8 S-2 2-2-2 5-3 1-1-2 S•4 1.1.2 S-5 3.3.2 GS S-9a o.1-1 �S•6b S-7 2-2-5 GS S-8 3.2-2 NOTE: This log or subsurface conditions applies only at the specified location and on the dais indicated and therefore may nd necessarily be indicative of olher times and/or locations, It• Standard Penetrallon Test (140 lb, weight, 3(" drop) • Blows Per foot �r 10 20 30 40 5D p } 20 40 60 Ito 10 Water Conlent (%) Plastic Limit 1--0 Liquid Limit Natural Water Content r-0 HS 1--15 1 L2 3 BORING, SW 34TH STREET CULVERT BH_1 SPRINGBROOK CREEK HWAGEOSCJENCES INC. RENTON, WASHINGTON PAGE. 1 of 3 PROJECT NO-! 2005-043 FIGURE: A-2 BORING 2DD5043.GPJ 5It8105 DRILLINO COMPANY: Hol000ae Mling SURFACE ELEVATION: 18.00 t feel DATE STARTED: 011112005 DRILLING METHOD: HSA: Mobile B-51 DATE COMPLETED: 4/1&2005 SAMPLING METHOD; SPT wJ Aulchammer LOGGED BY; B. Thurber LOCATION: See Site S Exploration Plan, Figure 2 3C 34 4C 45 5C DESCRIPTION Medium dense, black, clean, fare to medium SAND,wet. Masshre. SP------------------------ SM Medium donee, black, clean to silly, fine SAND, weL Partty decomposed trunk wood at 31 feet; 112-inch Ions, ML Very loose, dark olive -gray, non -plastic SILT (to 35.5 feet) over very soft plastic SILT, wet. Scattered shell fragments and woody fragments. One bivalve shell 1 inch long, JESTUARINE DEPOSITS) MIL SM Very loose, dark olivo-gray, plastic and non -plastic SILT, wet. Grades to fine sandy SILT. Very loose, gray, silty, fine to medium SAND with beds of SM sandy SILT, wet. Scattered shalt fragments, nearty whole to delrilal (t 118 inch). Scattered woody fragments. ---------------------- SP SM Loose, gray, slightly silly, fine to madium SAND, wet. Finely bedded. Scattered shell frag_monls. -- _ _ _ _ _ _ _ MIL Sdt, nllve•brown, slightly sandy SILT, molat to wet. Finely SM bedded. Partly decomposed woody fragments in two lenses, < 114 inch, at 45.75 and 46.5 feet. ---------------------- SM Standard Penetration Test m d (140 lb. weight, 3(r drop) • Blows per fool t„ a O0 0 10 20 30 40 &9 Si1-11 S-10 34-6 GS ;-11a 0-M ;-11 b S-12 CN i-13e 0-0-0 i-13b ;-14a 3-2-2 i-14b 0 2u 4U ou ou Water Content (%) Plastic Limit 1 0 Liquid Limit Natural Water Content NOTE: This log of subsurface conditions applies only at The specified location and on the date indicated and therefore may not neoeesarity, be indicative of other times andror locations, BORING: SW 34TH STREET CULVERT BH_1 SPRINGBROOK CREEK HWAGEOSCIENCES INC RENTON, WASHINGTON PAGE: 2 of 3 —25 100 PROJECT NO.: 2005-043 FIGURE: A-2 BORING 2D05043.GPJ U19105 DRILLING COMPANY: Holocene Drillfng SURFACE ELEVATION: 18.00 t feet DATE STARTED: 411WOOS DRILLING METHOD: HSA: Mobile B-51- DATE COMPLETED: 411 WOOS SAMPLING METHOD: SPT W Autdmmmer LOGGED BY: B. Thurber LOCATION: See She A Exploration Plan, Figure 2 Q r� 50 r rrr- 60 - Kim 70 - 75 •- ' - IL IL DESCRIPTION a w I Loose. gray, aflghtly silly to silty (stratified) Are SAND. wet. 5-15 3-23 Scattered tenses of partly decomposed woody debrio- 111 IICJy41{l 2-inch lens of clean, fine to medium SAND at 50.26 feet. Very soft, gray, plastic SILT, wall. Scattered shell fragments. Fine sand lenses (114 Inch) at 55.5 and 56.5 feet - Very soft, gray, SILT, moist to wet. Scattered shell fragments, woody organics. Massive, Borehole terminated at 81.5 feat. Ground water encountered at approx. 10 feel during drilling. Auger Tilled with drilling mud below 10 feet to prward heave. NS-17 0." NOTE: This log of subsurface conditions applies only at the specifiad lacarion and on the date Indicated and therefore may not necessarily be Indicative of other times and/or Iccotions. AL Standard Pe"rallon Test (140 lb. weight. 30" drop) A Blom per f0e4 P n •n nn nn :n rn 0 20 40 so 80 Water Content (%) Plaslic urnit 1 0 Llquld Limit Natural Water Conlerd SW 34TH STREET CULVERT BORING: 1 SPRINGBROOK CREEK BH-1 HWAGEOSCIENCES INC. RENTON, WASHINGTON PAGE: 3 of 3 55 _TO -j i— 75 100 PROJECT Na: 2005-043 FIGURE: A-2 BORING 7005043.GPJ Ul W5 DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 18.50 t feel DATE STARTED: 411W005 DFtILLING METHOD: NSA: Mobile B-51 DATE COMPLETED: 4/1=005 SAMPLING METHOD: SPT wl Autobammer LOGGED BY: B. Thurber LOCATION: See Site A 6q&ralian Plan, Figure 2 rb Standard Penetration Test _ EL F H (140 lb, weight, 30' drop) rn ♦ Blom per kw `c3 2 2 z dg DESCRIPTION V) h C O 0 10 20 30 40 50 y 4 0 k •: S-1 2-2-2 -..;.. j. .. j. ._. 5 4............i..,*................... g S-2a 0-2-2 S-2b i4 S-3a 0� 1 S-3b 10 A ...........:....C-�.:. ;.........:....c,... 10 002 �S4 .j.... I. .I. .r. S 5 A-" .j. .j. .j. ,j. 15 ..... ... ......... .....:....:....:.... 15 S-6 3-5.6 GS A � 8-7 G-0.2 20 .....,.:...�........................ 20 S S 4-0 1 GS r ;. 25 25 0 20 40 80 100 Water Consent {%) Plastic Limit F--0-- Liquid Limit Natural Water Cordon] NOTE; This log of subsurface conditions applies only at the specified localion and on the date indicated and therefore may not necessarily be indicative or other times andlor locations, .' SM Sod Loose, rust -mottled brown, silty, fine to medium SAND, moist. Scattered fine gravel. {FlLL} SM Loose, purple -brawn, very silty, fine SAND, moist _____---�ALLLMIIfr�------w W—...— OL Sofl, dark brawn, orparric SILT, moist- Scattered fibrous organics. Sofl, pray, bon -plastic SILT, wet- SeaHered rootlets. ML w°°dy fragments in lever 3 inches — � — — — — DL Soft, dark brown, organic SILT, we!- Abundant wood _ fragments, leaves {detrital}. _ Lens ofgray_siHat7.751oBfeet. __________ ML Soft. bream -gray, SILT, wet. Abundant fibrous organics. SP Very kwse, gray, clean, fine SAND, wet. With bock of SM brown -grey SILT, dark brown organics, and fine 1c medium SAND. Loose to medium dense, dark pray, slightly silly to silly, knew SM la medium SAND, wet. Stratified, with lenses of non -plastic SILT. Medium dense, black, clean, fine Ic medium SAND, vat, SP Mostly black grains, some red. Very soft, grey, SILT, wet. Scattered shall end woody ML fragments. 1!2 inch lens of yellow, non -plastic SILT at 18.5 feel {Volcanic ash?). Very loose, interbedded dark gray, slightly silty, fine SAND SP SM and black, dean, fine to medium SAND, wet. With lenses of purple -broom SILT and silly fine SAND. Scattered woody organics- ---------------------- ML SM UM BORING: SW 34TH STREET CULVERT BH_2 SPR1NGBROOK CREEK HMGEOSCIINCES INC RENTON, WASHINGTON PAGE: 1 of 3 PROJECT NO.: 2005-043 FIGURE: A -a gOgrrrc 2005643.GPJ 5J19r05 DRILLING COMPANY: Hoboene Drilling SURFACE ELEVATION: i8.50 t feet DATE STARTED: 4118/20DS DRILLING METHOD: HSA; Mobile 8-51 DATE COMPLETED: 4/18/2005 SAMPLING METHOD: SPT w/ Autohemmer LOGGED BY: B. Thurber LOCATION: See She & Explaretion Plan, Figure 2 1 30 I 35 1 40 W2 1 50 DESCRIPTION cc w C CO a a - T I o± z a X_ o Soft, gray -brown, SILT, rune sandy SILT, and dark gray, silly One SAND, wet. 7-Inch long branch In lower 9Inches (blow counts overstated (ESTUARINE DEPOSITS) Loose, dark gray to dark purple -gray, Ana sandy SILT, wet Non -plastic. Scattered shell fragments in two lenses, Veryloose, dark gray, slightly fine sandy, non -plastic SILT, moist to wet. Finely bedded. Scattered shell fragments. Very krone, gray interbedded SILT, sandy SILT, and silty fine to nwmfium SAND, wet. Abundant shell fragments. SM----------------------- Very loose, gray, very silty, tine to medium SAND grading to dean, fine to, medium SAND, wet. Abundant shell and wood fragments. -----------------..... -- SM S-9 2-4-12 -10 24.2 Gs i-11 0-0-0 i•13 0-0-0 4-14 04).0 tJOTE, This log of subsurface conditions applies only at the specified location and on the dare Indicated and therefore may not necessarily be indicative of other limes and/or lw:atbns. Standard Penelratian Test (140 lb. weight, Nr drop) A Blows per foot Water Conlenl (%) Plastic Limit 1--0 Uquld Limit Natural Water Content SW 34TH STREET CULVERT BARING:BH-2 1 SPRINGBROOK CREEK HWAGEOSCIENaS INC. RENTON, WASHINGTON PAGE: 2 of 3 PROJECT NO.: 2005-043 FIGURE! A-S BORING 2005043.GPJ 571B/0S DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 18.50 t feet DATE STARTED: 4/18/2005 DRILLING METWM. HiSA; Mobile B-51 DATE COMPLETED; 411MOOS SAWLING METHOD: SPT wl Autohammer LOGGED BY: B, Thurber LOCATION: See Site E Exploration Plan, Figure 2 J r0 55 - 60 - 65 - 70 75 - DESCRIPTION Very loose, gray, non -plastic SILT and fine sandy SILT, and very soft, plastic SILT, wed. Scattered shell fragments. Very soft, brown -gray, plastic SILT, moist to wet, Finely bedded. Scattered shell fragmenls. Sample deformed laterally when sampler opened; very sticky sift. S-15 0-0-0 NS-16 0-" Very soft, brown -gray, plastic and non -plastic SILT, moist. I NS-17 0-0-0 A few laminae of fine SAND. Scattered shell fragments, up to 314 inch across. Borehole terminated at 61.5 feet. Auger filled with drilling mud below 10 feel to prevenl heave (therefore ground water level obscured)_ NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times andlor locations. Standard Penetration Teal (140 lb. weight, 30" drop) A Blows per fool 0 20 40 60 80 Water Content (96) Plastic Limit 1 0 Liquid Limit Natural Water Content SW 34TH STREET CULVERT BORING: BH-2 SPRINGBROOK CREEK IMGEOSCIENCES INC RENTON, WASHINGTON PAGE; 3 of 3 60 L21 70 PROJECT No.: 200 -043 FIGURE: A-3 BORING 20054r3.GPJ W1W 5 APPENDIX B LABORATORY TEST RESULTS 1111110 i GRAVEL SAND SILT CLAY Coarse Fine Coarse Medium Fine SYMBOi_ SAMPLE DEPTH (ft) CLASSIFICATION OF SOIL- ASTM Q2487 Group Symbol and Name 36 MC LL PL pl Gravel Sand Fines • BH-1 5-5 12.5 -1b.4 (SPSM) Black, Poorly graded SAND with silt 27 O,t] 9D.7 9.3 ! BH-1 S-7 17.5 - 19.9 (SM) Dark broom, Silty SAND 31 4,0 5B.4 41.6 A 9H-1 S-10 30.0 - 31.5 (SM) Black, Silty SAND 32 0.1 >35.4 i4.5 ULTA SW 34TH STREET CULVERT PARTICLE -SIZE ANALYSIS SPRINGBROOK CREEK OF SOILS HWAGEOSCIINCES INC. RENTON, WASHINGTON METHOD ASTM D422 PRo.OEcTNo: 2005-043 FIGURE: HWAGREZ Z=043,GPJ 5118105 - �ISYMBOL SAMPLE DEPTH (tt) CLASSIFICATION 4f SOIL- ASTM D2487 Group Symbol and Name 76 MC LL PL PI Ckavel !622.5 Fines * BH-2 S-& 15,0 - 16.5 (SM) Dark pray broom, Silty SAND 30 4.0 18.8 * BH-2 S� 20.0 - 21.5 (SM) Dark brown, Silty SAND 29 1.2 36.3A BH-25-10 30.0-31.5 (ML) Dark Qrayish brown, SILT 36 89.8 1 SW 34TH STREET CULVERT PARTICLE -SIZE ANALYSIS � sPRiNGeRooK CREEK of solLs METHOD ASTM D422 HWAGEOSCIENG'ES INC RENTQN, WASHfNGTON ps:o..rECT Na.: 2005-043 11=rauae: B-2 14WAGR5Z 2I705043.GPJ 51191g5 60 CL G 50 w 0 }a F— 3 0 U Q 20 J 10 f CL-ML ML MH 0 0 20 40 60 80 100 LIQUID LIMIT (LL) SYMBOL SAMPLE DEPTH (ri} CLASSIFICATION % MC LL PL Pt °% Flees BH-1 5-18 55.4 - 56.5 (CL) Dark gray, CLAY 52 38 2'{ 17 SW 34TH STREET CULVERT LIQUID LIMIT, PLASTIC LIMIT AND Y I:lilI SPRINGBROOK CREEK PLASTICITY INDEX OF SOILS HWAGEOSCIENCH INC, RENTON, WASHINGTON METHOD ASTM D4318 PROJECT NO: 2005-043 FIGURE; B-3 FfWAATT9 2005043GPJ 5079M5 1.14 1.05 1.00 a: 0.95 -- O t=- o 00.90 0.85 0.80 0.75 0.1 1 10 100 STRESS tksq SAMPLE DEPTH (R) CLASSIFICATION BH-1 5-12 37.5 - 39.5 (CL) Gray, CLAY INITIAL FINAL LIQUID LIMIT, LL (%) WATER CONTENT (%) 44.7 30.0 PLASTIC LIARrf, PL (%) DRY DENSITY (pCf) 76.1 82.0 PLASTICffY INDEX, PI (%) DEGREE OF SATURATION(°h) 89.9 100 ASSUMED SPECIFIC GRAVITY 2.68 ONE DIMENSIONAL CONSOLIDATION S.W. 34th Street Culvert PROPERTIES OF SOIL HWAGEOSCIENJCE INC. METHOD ASTM D2435 PROJECTNO.: 2005-043-1100 mcul�: .__ B-4 HWAGONV 20050I31100.GPJ 5119105 Station num, -S9b (obser) Table of daily values for the 12-month period ending September 1997 Observed Flow (efs) SPRINGBROOK CK. AT SW 27th ST (observed) Day October November December ]anuag Annual 1 2.8 4.1 58.0 499.5 2 2.7 3.4 40.0 436.7 3 2.9 6.1 20.0 - 4 40.6 12.4 113.8 - 5 27.0 3.4 116.5 - 6 3.4 9.5 102.3 - 7 29 5.2 136.3 19.5 8 2.8 3.1 190A 43.8 9 2.8 3.0 130A 45.3 10 2.8 3.0 106.2 31.0 11 4.7 3.0 65.9 16.9 12 3.1 32.8 98.9 10.9 13 37.8 116.1 86.6 9.5 14 28.4 38.6 33.0 8.5 15 13.4 31.7 14.9 7.7 16 5.7 16.7 30.3 22.4 17 24.5 32.7 9.5 194.6 18 100.4 92.6 8.0 160.0 19 7.7 68.0 14.4 147.3 20 3.5 81.2 45.4 202.2 21 12.9 70.3 35.6 143.0 22 65.6 29.2 10.3 86.7 23 19.4 19.0 57.4 57.5 24 64.1 116.7 82.3 34.3 25 21.0 105.1 113.6 21.9 26 5.1 40.7 68.3 12.1 27 3.6 192.9 199.6 26.0 28 69.2 170.8 108.7 70.2 29 74.1 76.4 2.27.9 24.4 30 8.9 56.3 478.2 179.3 31 5.2 500.9 91.5 Mean 21.6 48.1 206.E 94.2 67.6 Minimum 2.7 3.0 8.0 7.7 2.7 Maximum 100.4 192.9 500.8 499.5 500.8 Station num. : S% (obser) Table of daily values for the 12-month period ending September 1996 Observed Flow (c(s) i SPRINGBROOK CK. AT SW 27th ST (observed) Day October November December January February March Aril May June July An st S tember Annual 1 32.7 2.7 187.9 10.1 9.1 7.9 84.5 8.3 3.0- 2.8 4.2 5.2 2 10910 2.7 147.3 20.0 8.2 7.3 21.0 6.9 3.0 2.8 28.9 4.0 3 123.0 2.6 106.2 49.8 11.6 41.1 6.3 7.4 3.0 3.0 104.3 33.2 4 83.4 2.7 153.9 10.t 39.3 16.1 4.9 5.5 2.9 4.6 11.8 10.3 5 56.7 2.9 - 13.4 98.8 9.2 4.2 4.9 2.9 3.0 5.5 5.5 6 49.2 3.0 - 45.7 182.S 7.3 31.9 4.5 2.9 2.9 4.7 7.2 7 46.1 145.3 - 245.7 163.7 6.9 7.8 4.2 2.9 2.9 4.4 4.5 8 63.6 179.4 - 102.7 540.3 6.7 4.9 3.9 2.9 3.0 4.2 3.8 9 63.4 49.3 - 52.7 677.1 6.7 5.1 3.7 2.9 3.0 4.1 3.3 10 195.5 34.5 - 29.3 - 42.7 5.0 3.4 2.9 3.0 5.0 3.5 11 201.1 208.4 - 14.9 - 63.3 7.0 5.2 2.9 3.0 4.9 3.4 12 90.7 67.0 - 10.5 - 10.6 7.3 40.7 2.9 3.1 4.8 3.3 13 17.1 48.6 - 14.5 - 8.1 4.9 154.7 2.9 3.1 4.9 3.5 14 8.6 14.2 - 100.7 - 6.9 4.0 18.9 2.9 3.1 5.0 7.7 15 7.1 30.7 - 266.2 - 5.7 17.9 7.2 2.9 3.1 4.9 37.3 16 29.8 13.9 197.6 - 5.2 79.2 5.5 2.9 3.2 4.8 5.6 17 13.7 8.5 - 98.4 - 4.9 11.3 17.5 2.9 6.7 4.8 24.0 18 8.1 20.2 - 60.9 - 4.7 19.8 53.1 2.9 17.6 - 4.8 8.3 19 3.2 7.2 - 97.9 - 7.4 19.9 33.3 2.9 32.7 4.6 43.4 20 41.8 5.8 - 156.6 - 6.6 9.0 7.7 3.0 6.7 4.6 6.4 21 11.6 5.1 - 189.3 - 6.2 6.1 7.1 2.9 4.6 4.4 4.4 22 3.4 19.3 9.3 111.8 50.9 16.0 50.2 14.3 2.9 4.1 4.4 5.7 23 2.9 88.1 8.2 86.8 81.9 6.2 378.4 6.1 12.4 3.8 4.2 3.1 24 2.9 92.8 7.3 114.2 40.0 5.1 289.6 4.7 5.5 4.2 4.0 3.0 25 5.2 113.9 6.5 85.5 22.0 4.3 123.8 4.0 3.6 4.2 3.9 2.9 26 5.6 47.9 6.1 54.9 13.2 4.2 99.2 3.5 3.0 4.2 3.8 2.9 27 2.9 51.4 5.9 35.4 10.5 5.4 50.4 3.3 2.9 4.4 3.7 2.8 28 2.8 87.9 9.0 17.8 9.4 4.1 28.5 3.1 2.9 4.2 3.6 2.8 29 2.7 322.4 101.5 21.1 8.6 3.9 14.5 3.1 2.9 4.3 3.3 2.8 30 2.7 195.9 92.9 10.8 3.6 9.3 3.1 2.8 4.2 3.9 2.9 31 2.7 24.9 9.8 229 3.1 4.3 5.3 Mean 41.5 Minimum 2.7 Maximum 201.1 62.5 57.5 15.3 121.3 I1.5 46.9 14.6 3.3 5.2 8.7 9.6 2.6 3.6 9.8 8.2 3.6 4.0 3.1 2.8 2.8 3.3 2.8 322.4 187.9 266.2 677.1 63.3 378.4 154.7 12.4 32.7 104.3 43.4 38.1 2.6 677.1 Station num. : S9b (obser) Table of daily values for the 12-month period ending September 1995 Observed Flow (efs) SPRINGSROOK CK. AT SW 27th ST (observed) Day October November December January Februa March April Ma June July August S tember Annual 1 4.4 32.1 141.3 26.8 135.3 9.8 6.7 4.0 2.8 3.7 2.9 8.0 2 5.0 19.9 110.8 15.7 107.4 9.3 6.1 36.1 2.9 6.1 2.9 8.0 3 4.6 10.2 41.6 11.1 59.9 8.9 6.0 4.9 2.9 6.0 2.9 7.7 4 4.2 58.5 18.8 10.3 36.1 16.0 7.9 3.5 3.2 4.9 2.9 20.7 5 4.0 15.2 10.6 9.8 22.9 9.6 6.0 3.4 19.5 4.3 4.0 137.5 6 5.5 16.1 9.9 9.2 14.4 8.3 5.7 3.1 7.8 4.2 30.7 1069 7 6.2 9.0 9.2 10.6 10.8 7.9 27.2 3.0 3.9 4.1 56.3 41.8 8 6.7 14.0 8.5 17.3 10.1 48.6 29.8 3.2 3.2 3.9 24.0 14.4 9 7.4 64.9 20.7 35.5 9.6 92.1 6.8 3.5 3.1 59.5 10.1 9.3 10 7.5 17.2 9.7 85.8 8.8 135.0 13.6 4.9 8.5 63.1 12.4 8.7 11 6.3 10.0 9.1 57.7 13.6 111.9 17.6 6.0 13.5 8.0 16.3 7.9 12 6.3 21.6 21.1 26.5 9.3 94.9 27.1 3.2 4.4 5.6 10.0 7.5 13 7.5 8.9 8A 55.9 8.0 64.8 39.9 3.0 9.3 4.4 9.3 7.4 14 27.5 9.0 13.2 53.2 7.4 88.7 7.5 2.9 5.2 3.7 9.7 7.3 15 7.2 19.4 31.3 32.9 23.0 46.3 6.7 2.9 6.3 3.4 10.5 7.1 16 6.8 70.6 85.6 18.0 15.5 24.4 5.7 2.9 4.3 3.1 14.4 7.1 17 7.3 19.5 173.7 11.4 72.4 14.0 5.4 2.9 9.2 3.1 198.3 7.0 18 7.9 9.2 106.8 41.5 127.5 68.6 5.2 2.9 9.0 3.1 75.8 7.6 19 8.1 23.1 112.0 14.5 368.2 42.6 4.9 2.9 4.7 3.0 29.2 8.9 20 11.2 53.2 236.5 10.0 292.0 69.8 21.9 2.9 7.7 3.0 22.2 8.8 21 10.5 9.9 191.5 9.2 132.5 23.2 5.4 2.8 5.1 3.0 33.2 8.6 22 8.4 8.3 81.4 8.6 88.1 14.9 4.5 2.8 4.2 3.0 15.2 8.3 23 9.8 26.1 53.8 8.2 67.4 74.1 4.2 2.9 3.7 3.0 9.7 8.2 24 9.9 9.0 33.6 8.0 53.6 20.0 3.9 2.8 3.9 3.0 9.1 8.2 25 11.8 27.6 23.9 7.7 42.7 10.3 3.6 2.8 3.7 3.0 9.0 8.4 26 120.5 67.5 198.8 7.5 22.9 9.1 3.3 2.9 3.6 37.4 9.0 9.2 27 168.4 47.9 316.7 7.1 13.3 8.4 3.3 2.8 3.5 5.9 8.5 55.5 28 40.6 12.3 - 16.3 10.5 7.8 3.2 2.8 3.5 3.2 8.4 60.0 29 9.5 31.8 89.6 118.2 7.5 4.6 2.8 3.4 3.0 8.4 29.3 30 13.1 222.0 58.9 107.4 7.2 7.3 2.9 3.7 2.9 8.1 58.5 31 98.3 42.6 161.9 6.8 2.8 2.9 8.0 Mean 21.0 32.1 75.3 32.7 63.7 37.4 10.0 4.3 5.7 8.7 21.7 23.1 28.0 Minimum 4.0 8.3 8.1 7.1 7.4 6.8 3.2 2.8 2.8 2.9 2.9 7.0 2.8 Maximum 168.4 222.0 316.7 161.9 368.2 135.0 39.9 36.1 19.5 63.1 198.3 137.5 368.2 Station num►... -S9b (obser) Table of daily values for the 12-month period ending September 1994 Observed Flow (efs) SPRINGBROOK CK. AT SW 27th SP (observed) r Day October November December Januag Februag March April Kay__June 4 July_.Au Mt S tember -Annual 1 2.5 2.8 - 60.8 3.1 44.8 3.4 5.7 15.0 31.1 6.0 4.7 2 2.5 2.8 9.8 38.2 3.0 92.2 3.2 5.6 8.0 28.5 5.7 4.7 3 2.5 5.6 6.9 26.0 3.0 151.4 19.5 5.4 8.1 9.6 5.7 18.2 4 2.5 3.0 24.5 35.5 3.0 94.5 16.2 25.6 9.9 9.6 5.5 10.1 5 2.5 2.9 4.9 42.9 3.0 31.9 5.0 6.3 11.3 47.8 5.4 5.0 6 13.0 2.9 3.7 8.6 3.0 11.1 44.8 5.7 38.9 12.1 5.1 3.9 7 7.1 3.0 34.0 6.7 3.0 8.4 41.5 5.7 20.5 9.0 5.2 3.7 8 2.6 3.0 46.6 13.6 2.9 7.1 105.6 5.6 9.1 9.4 .10.3 16.2 9 2.6 3.2 90.4 7.3 4.9 6.2 23.5 5.8 8.4 7.9 10.9 9.4 10 2.5 3.1 99.9 10.1 3.1 15.0 8.1 5.9 8.4 7.7 7.0 12.0 11 2.5 3.3 53.2 16.4 2.9 9.6 6.1 6.0 8.5 7.6 5.3 3.2 12 2.5 3.1 10.1 9.5 2.9 5.7 48.1 6.0 10.7 7.4 5.0 2.8 13 2.5 3.1 24.1 6.5 72.3 5.1 10.5 6.1 52.3 7.1 3.1 2.8 14 2.6 3.1 10.0 5.1 17.1 4.6 6.5 6.9 45.4 7.2 3.7 7.0 IS 4.6 4.5 7.2 4.3 27.5 4.6 4.9 16.9 13.4 7.6 3.9 5.1 16 11.6 7.8 5.3 3.6 101.8 19.0 4.2 24.9 9.8 8.1 4.0 4.3 17 2.7 11.0 4.2 3.4 98.4 25.2 3.7 8.3 12.6 7.8 4.3 4.1 18 2.6 9.1 3.6 3.2 73.6 48.4 3.5 7.0 99.5 7.9 4.4 4.2 19 2.6 3.7 3.2 3.1 18.8 11.0 3.3 6.8 17.9 7.7 3.3 4.6 20 2.6 3.7 3.0 3.1 8.6 46.8 3.2 6.9 11.0 7.5 3.9 5.1 21 2.6 6.0 3.1 3.4 7.8 63.5 7.3 6.9 9.8 7.5 4.4 5.2 22 15.8 7.4 2.9 59.7 10.5 30.6 3.9 6.9 9.5 7.3 4.6 5.4 23 80.3 5.1 2.9 41.4 37.4 15.3 3.3 6.9 9.2 7.2 5.2 5.7 24 18.1 4.5 2.9 14.2 13.1 7.6 3.2 6.8 9.7 7.3 4.3 4.6 25 4.1 4.5 2.8 13.5 39.2 6.2 3.2 6.9 9.6 7.4 4.3 4.7 26 2.9 4.7 2.8 6.0 50.0 5.4 3.8 6.9 9.2 7.1 4.5 4.8 27 2.8 4.9 2.8 4.7 48.4 4.8 4.3 7.7 9.2 6.7 4.7 4.8 28 2.9 7.5 2.8 3.9 29.3 4.5 4.5 7.4 9.1 6.6 4.7 5.3 29 2.8 44.1 2.9 3.5 4.1 5.4 23.4 9.2 6.8 4.7 5.1 30 2.8 15.0 29.6 3.2 3.8 7.9 12.3 9.5 6.6 4.7 4.2 31 2.9 35.2 3.1 3.6 11.1 6.2 4.8 Mean 6.9 6.3 17.5 15.0 24.7 25.5 13.7 8.9 17.1 10.5 5.1 6.0 13.1 Minimum 2.5 2.8 2.8 3.1 2.9 3.6 3.2 5.4 8.0 6.2 3.1 2.8 2.5 Maximum 80.3 44.1 90.4 60.8 101.8 151.4 105.6 25.6 99.5 47.8 10.9 18.2 151.4 RENTON SW 27TH STREET: CULVERT REPLACEMENT FLOW DATA Units: cfs June July August September Overall Fish Window mean peak mean peak mean peak mean peak mean peak 1996 1995 1994 17.1 5.7 3.3 98.5 19.5 12.4 10.5 8.7 52 47.8 63.1 32.7 5.1 21.7 8.7 10.8 198.3 104.3 6 23.1 8.6 18.2 137.5 43.4 9.7 98.5 14.8 198.3 6.5 104.3 AVE 8.7 43.5 8.1 47.9 11.8 104.5 12.6 66.4 10.3 133.7 AVE AVE PEAK June 8.7 43.5 July 8.1 47.9 August 11.8 104.5 September 12.6 66.4 AVE j 10.3 65.6 16.00 15-00 14.00 13-00 12.00 11-00 9.00 8.00 7.00 6.00 5.00 400 lir,dre I Spdngbroolc Creels at SW 27th Street Rating Curve (9 July 1997) NHC Discharge Measurements ................................. - - - ---------- ----------------- ---------------- ............ ............ ..................... ................ 4 ........... - --- -------- ....... ............. ---------- ----------------- ................ ............ . ............... ............. I ....... ........... ---------------- 4 ........ ... ---------- ------- ......... — -- --------- ----- - A -0 ................ ----------------- --------- ------- 4 ------ ---------------- ----------------- -----............ -------------- --- -------- ....... ................ Uses double entry , sting CU4e above elev. .9.91t, NGVD ......................... ...... .......... ----------------- -------------------------- ------- ------ ---------------------------- "',— ------- ............... rL 6A 4 --------------- ......... ---------- ....... . ........ ....................... ---- --------- --------------- ................ ............... . /* -------------- . ............................ -------------- --- - ---- ------------------------- -------- -------- . ................ ----------------- .... - {............. . . .. ------------ - ---- - ----------- ------- . - -- .... ...-------- ............................... ---------------- --------- ------- - - - -- -------- ---------- .......................... - - - ---------- —.- ------------- — ------ 0,0 200.0 400.0 600.0 800.0 1000.0 Flow (Cfs) '-e D z A c- rOV-SU'l -AAA