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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 i t 1 1 t 1 1 November 2005 1 r ' CERTIFICATION PAGE SW 34�h 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 seal as a registered professional engineer is affixed below. 24055 ,NAI,E~��► �,Z3 Michael S. Gisebdit, Project Manager =xFi�ES: IZ - opt-Oh r COPYRIGHT 2005, R. W. BECK, INC., ALL RIGHTS RESERVED. i 1 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'x10' Box Culvert.............................................3-4 ' Other Options ...........................................................................................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 1 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 UtilityRelocations .............................................................................................4-3 CulvertFoundations...........................................................................................4-4 Road and Sidewalk Modifications.....................................................................4-5 Environmental Considerations........................................................................... ' 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 34th Street Culvert and ' Culvert Replacement Alternatives...................................................................3-7 Table 2 Predicted Maximum Velocities at SW 34th 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 Alternative 2 Cost Estimate.......................................................End of Section 3 Figures , Figure 1 Project Area Map Figure 2 SW 34th Street—Existing Survey ' Figure 3 SW 34th Street—Existing Profile and Utilities Figure 4 SW 34th Street—Alternative 1 - Plan Figure 5 SW 341h Street—Alternative 1 - Sections ' Figure 6 SW 34th Street— Sanitary Sewer Relocation Figure 7 SW 341h Street—Alternative 2 - Plan Figure 8 SW 34th Street—Alternative 2— Sections ' Figure 9 SW 34th 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 ll Working Final Report.doc 11/22/05 , ' 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 11/21/05 111 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 I-405 to the north, Talbot Road S to the east, SW 43`d Street to the south, and the Renton City limits to the west. ' The ESGRWP identified the replacement of the SW 34th 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" 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 271h Street Culvert Replacement Project in 1999. The ' SW 341h 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 Report.doc 11/21/05 Section 1 r will provide the desired flood protection objectives in the valley area. One of the , future planned projects is the SW 43rd 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 1 , includes the following pre-design work for the SW 341h Street Culvert Replacement prof ect. ■ 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 341h 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, P.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, P.E., project manager, and Lisa Gorry and Rick Lippold, P.E., project engineers. 1 1-2 R. W. Beck Working Final Report.doc 11/21/05 ' 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 field 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 341h 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.doc 11/21/05 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 t —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 34th 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 t (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 341h 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 50-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 341h 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 34th 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 341h 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 341h Street in the City of Kent. 2-2 R. W. Beck Working Final Report.doc 11/21/05 ' 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. Geotechnlcal ' 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-lane 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 local 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 Report.doc 11/21/05 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 27 IhStreet 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. ' 1 1 1 2-4 R. W. Beck Working Final Report.doc 11/21/05 ' 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 primar� 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 (MRCS) (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: ■ 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. 1 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 11/21/05 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 27tn Street Culvert Replacement Project was 140 cfs, which considered historical flows during the time period of construction. r+ ■ 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 box is generally preferred over 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 Report.doc 11/21/05 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 1 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 34th 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'x10' 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 34th 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 34th 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 r 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. It 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 t 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 271h 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 Report.doc 11/21/05 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 ■ SW 39th Street to SW 43rd Street Pipe System Improvements ■ Renton Wetland Mitigation Project ■ Oakesdale (SW 41 St 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 teak 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 11/21/05 ' ALTERNATIVE ANALYSIS conveyance system (including the four 72-inch diameter culverts at SW 341h 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 34th Street(2) 100-yr Change in Future Downstream Upstream W.S. El. AlternativeM Flow W.S. El. 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 88. 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 losses. 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 1 Working Final Report.doc 11/21/05 R. W. Beck 3-7 Section 3 , conditions in the basin, velocities were also checked for future land use conditions. t 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 FIow3 Surface Velocity FIow3 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 14.9 2.7 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 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 AASHTO 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 Report.doc 11/21/05 , i 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'xT 4-sided box culverts $1,770,000 2 Single 30'xl0' 4-sided box culvert $1,385,000 Based on these cost estimates, Alternative 2, the single box, is significantly less expensive than Alternative 1. 1 Working Final Report.doe 11/21/05 R. W. Beck 3-9 Section 3 Construction Impacts 1 Both the alternatives will involve the disruption of traffic on SW 34th 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 34th 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 341h Street than Alternative 1, 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 Report.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 1 alternatives. Alternative 2 requires the need for constructing a separate bypass, but Alternative 1 has a larger 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 Report.doc 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 341n 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 Report.doc 11/21/05 TABLE 5 COST ESTIMATE -ALTERNATIVE 1 Item Quantity Units Unit Price Cost General and initial construction traffic control and safety 1 LS $15,000 $15,000 temp ESC 1 LS $14,000 $14,000 relocate SS approx 900'east, including manholes 900 LF $120 $108,000 SD structure with SS pipe penetration 1 EA $6,000 $6,000 ground water dewatering 1 LS $130,000 $130,000 Qwest relocate communication duct $0 PSE relocate power and gas $0 ' Install Diversion upstream and downstream cofferdams 1 LS $6,000 $6,000 Phase 1 (southwest construction) Sheet pile wall at CL SW 34th 910 SF $20 $18,200 pavement and sidewalk demo(for phases 1 thru 4) 900 SY $6 $5,400 temporary relocate 12"water 1 LS $6,000 $6,000 excavate for box culvert and SW retaining wall 2300 CY $10 $23,000 haul excavation 2300 CY $10 $23,000 1 extra cost for CMP removal 1 LS $4,000 $4,000 subgrade fabric reinforcement 200 SY $5 $1,000 subgrade crushed rock backfill 150 CY $30 $4,500 procure & deliver 40 IF, 30'x 6' 4 sided box culv 40 LF $1,650 $66,000 install box culvert 1 LS $7,000 $7,000 southwest wing wall 600 SF $35 $21,000 backfill phase 1, imported 1242 CY $15 $18,630 streambed gravels and improvements 100 CY $30 $3,000 Phase 2 (northwest construction) pull and relocate sheet pile shoring 280 SF $20 $5,600 temporary relocate 12"water line 1 LS $5,000 $5,000 excavate for box culvert 1960 CY $10 $19,600 haul excavation 1960 CY $10 $19,600 extra cost for CMP removal 1 LS $4,000 $4,000 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 northwest wing wall 600 SF $35 $21,000 backfill phase 2, imported 700 CY $15 $10,500 streambed gravels and improvements 100 CY $30 $3,000 Phase 3 (northeast construction) remove and reinstall cofferdams 1 LS $6,000 $6,000 pull and reinstall sheet pile 770 SF $20 $15,400 excavate for box culvert 1540 CY $10 $15,400 r 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 misc 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 r TABLE 6 COST ESTIMATE -ALTERNATIVE 2 ' Item Quantity Units Unit Price Cost General and initial construction traffic control and safety 1 LS $10,000 $10,000 temp ESC 1 LS $12,000 $12,000 1 relocate SS approx 900' east 900 LF $120 $108,000 SD structure with SS pipe penetration 1 EA $6,000 $6,000 Groundwater dewatering 1 LS $110,000 $110,000 Quest relocate communication duct PSE relocate power Install Diversion initial pavement and sidewalk demo 700 SY $6 $4,200 trench excavation 1550 CY $10 $15,500 excavation haul 800 CY $10 $8,000 install 2-48" HDPE pipes 400 LF $68 $27,200 backfill north half, using excavated material 750 CY $5 $3,750 crushed surfacing for detour lane 30 CY $30 $900 upstream and downstream cofferdams 1 LS $6,000 $6,000 Phase 1 (south half construction) 1 temporary relocate 12"water line 1 LS $6,000 $6,000 sheet pile wall shoring 840 SF $20 $16,800 excavate for box culvert 1600 CY $10 $16,000 haul excavation 1600 CY $10 $16,000 extra cost for CMP removal 1 LS $4,000 $4,000 subgrade fabric reinforcement 200 SY $5 $1,000 subgrade crushed rock backfill 150 CY $30 $4,500 procure& deliver 40 LF, 30'x10' 4 sided box culv 40 LF $1,900 $76,000 install box culvert 1 LS $7,000 $7,000 South wing walls 900 SF $35 $31,500 streambed gravels and improvements 120 CY $30 $3,600 backfill phase 1, imported 1500 CY $15 $22,500 Phase 2 (north half construction) modify sheet pile shoring 200 SF $30 $6,000 temporary relocate 12"water line 1 LS $5,000 $5,000 excavate for box culvert 1600 CY $10 $16,000 haul excavation 1600 CY $10 $16,000 extra cost for CMP removal 1 LS $4,000 $4,000 subgrade fabric reinforcement 200 SY $5 $1,000 ' subgrade crushed rock backfill 150 CY $30 $4,500 procure &deliver 40 LF, 30'x10' 4 sided box 40 LF $1,900 $76,000 install box culvert 1 LS $5,000 $5,000 north wing walls 900 SF $35 $31,500 60"&36" storm drain modifications 1 LS $3,000 $3,000 streambed gravels and improvements 120 CY $30 $3,600 remove cofferdams 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 1 r 1 Section 4 RECOMMENDED ALTERNATIVE 1 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 34`h 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. 1 Because there is adjacent development at SW 341h 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. 1 , ' Working Final Report,doe 11/21/05 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 cfs with one foot , of freeboard. The required diversion capacity was based upon anticipated flows between a two-year and 10-year return period storm for the construction months. The diversion piping size for the SW 34th 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 will 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 341h 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 341h 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 Report.doc 11/21/05 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 11/21/05 ' 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 SW 341h Street in the immediate vicinity of the project. One approach to the vertical alignment modifications is shown on Figure 8. 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 Working Final Report.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. Cast-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 lower 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.doc 11/22/05 ' 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 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 (DARPA) 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 1 vzzios 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. Beck Working Final Report.doc 11/22/05 ' 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 34th 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. ' h Jones & Stokes. 2005. 34 tStreet Culvert Replacement Wetland Delineation and Stream Reconnaisssance Techncial Memornadum. May 24th. (J&S 05287.05) ' Renton, WA. ' R.W. Beck, Inc. 1997. 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 Final Report.doe 11/21/05 t � � I i sw 29th St NOTE: t I THE PROJECT AREA LAND USE IS DESIGNATED EMPLOYMENT AREA — VALLEY. II III � � I II I I II i I SPRINGBROOK I a CREEK I I I I SW 30th St - - I III I I I I I I I I I I 1 � I II o I IIII I III I � I III I I I I SW 34th St - - II - - - - SW 34th St ' I PROJECT AREA I I II I II i � i I � , I a � � I q I I I SW 39th St N PLAN E g SCALE: 1'=200' 200 0 200 400 1'=Z00'-0' Scale Feet 6%w— 1 -100' "° �'" fl CITY OF SW 34TH STREET to—at—os >E . , RENTUN CULVERT IMPROVEMENT PROJECT FIGURE 1 aiiia a, am I � OA�M Planning/Building/Pubrc works Dept PROJECT AREA MAP NO. REVISION BY DATE APPR •""0°°"' ' A-NNNNAA MAD r TM 0*INMM CO OM 0."'cla 0 w Cwu OF W15=101 Im Sff 3m wwr w o"mmf ME SF. "*'f 00014 OM WISE PONE "um EIEVATIDN . I0 ' C i Cn II ' I mm is= EE 13-%4 IE W 13AS i SIN PM NAL 9 FWIT OF VMU(AT N.W. • ' W E camn ammm ommay AWES N L E 1.205.3� HCRZONTAL QATUM* aB#JM ILM FM I i., 01 THE I MOM AVERICAN DATUM S3/91.HELD MEWS MC/ i _D NORTH 01-35-48-EASE BETWEEN MOW AT THE INTERSECTION OF LIND AVENUE E w 17A • SIN AND SW 30TH ST(NOT OPEN)AND UND AVENUE SW AND SIN 23RD sT(NaT OPEN). 0 W,17.0 ON ism VERTICAL DAUMm ' C4OEIE ! ASPNW NORTH AMERICAN VOWA DATUM Be.HELD CITY OF RDrmw mowNENT No. 1861 AT THE INTERSECTIONS OF LIND AVENUE sw AND sw 3DTm ST(NOT OPEN)ELEVATION 20.00 FEET AND MONUMENT No. 1551 AT LIND AVENUE SW AND SIN 23RD ST(NDT OW B.IL67 1OPEN)ELEVATION 2122 FEET. ow EL 13A 3' BH_2 DRA BMJI: TOP NORTHWEST BASE BOLT OF LIGHT STANDARD 1126 FEET EAST OF THE CENTERLINE OF SPRINGMW CREEK CONCRm ON NORTH SOE OF 34TH STREET SOUTHWEST. ELEVATION 1892 FEET 50 WETLAND BUFFER DHA WJ2. OrRIED SWME AT SOUTHEAST CORNER CONCRETE TRANWORMIR 1175 FELT WEST OF SPRINGBRCOK CREEK 50' WETLAND BUFFER CEICERLINE AND 12.0 FEET NORTH OF BACK OF WALK ON NORTH SIDE SOUTHWEST 34TH STREET. ELEVATION 21.10 FEET TOPOGRAPHIC MAPPING NOTES,' �/' f : t �._ 'Y BY DUNE HARTMAN A=M ............. THE MAP SHOWN HEREON 5 THE RESULT OF A TOPOGRAPHIC SIAIVE & TIES,INC-(DHA) COMPLETED ON APRIL 21.2DO5. ALL EXISTING UTILITIES SHOWN HEREIN WERE FIELD TIED AS A RESULT OF A UTILITY PAINT-OUT DURING THE COURSE OF THE FIELD SURVEY DUANE HARTMAN&ASSOCIATES,INC.(DEN)ASSUMES NO L"im sow mm 19.45 MR RE ACCURACY OF THE U111JTY PAINT--OUT. "ASSWES NO LIAMITY. BEYOND SAID DATE FOR ANY FUTURE SURFACE W ES THAT WAY OCCUR WITHIN OR AD""THE PERIMETER OF THIS SURVEY WETLAND 1 WK NME :yt IE FEATURE MODIFICATIONS OR CONSTRUCTION ACTTVITI A, E NE11111 WL 12M CONTACT DNA(425/483-5355)FOR SITE LPATES AND VERIFICATIONS. ' ` IN lim um SUWME i il=FEET i WETLAND 2 .. ......... ROAD CENTERJNE A MONUMENT IN CASE ROAD RIGHT-,OF-WAY --ib- PROJECT BENCHMARK 77"CAMP STORM CULVERT E-7.58 BUILDING x PK NAL(CONTROL) SP-6 IE iog 72CMP gm CUL g. VERT jj E-7.91 FENCE LINE REBAR AND CAP SPRINGBROOK CREEK INIM SWSXE IU7 FM VOM SLWXX 11M FET SPRINGBROOK CREEK I f i ------ FIE.8.12 w an PAL 0 04/11/mm am*qIq1wm 72r'CkiP Cuum T.-T IE-82� CONTOUR INTERVAL(2 FEET) CULVERT tCB. 9 ... ........... .............. Co I'm ❑(To 72CMP STORM SLAVERY. ...... FEM 0 SM DRAIN CATCH a4sN [E-8.34, em STORM DRAW CLIANOUT ' .r�p 1?.... -•-- BLDG BUILDING STORM DRAIN mmHDLE y. g .. .... 0 TWEI CUF CHAIN LINK FENCE CONFER TREE 5 EN01173A 011 TIFE 1 9,4 DECIDUOUS TREE . ..... CONS CONCRETE IL I&M 17.47 wr 1144 13 vul ' ... l.. CUP CORIZUGATED METAL PIPE SIGN 1~TIM Imm mw No cw sm"m mm ON 1323 • z EOC EXTRUDED CONCRETE CURB POTHOLE Im 27=r mm I&IS .............. ...... . .. ----- IELA.74 zu —y-w PK WL ORN ORNAMENTAL 0 SWARM SEWER MANHOLE SEr PK WL em 10.76 20 0 20 40 w L74 Z0_ 0a EL I&SO NE'.DO ASIAT FOUT i i ---- -,w jam"m 1*=20'-O" ORDINARY HIGH WATER U7111TY POLE WITH LIGHT NU L t PAIN WJR RXX OF MU ILP FEET N 18LDS&M Scale Fee PVC POLYVINYL CHLORIDE PPE POLE E 1.295.541M99 SINN W 2IA4 SINXIM IL57 FEET E E 14A SID SOL PLOT WATER HYDRANT 50, WETLAND BUFF SDMH STORM DRAIN MANHOLE WATER VALVE SSMH SANITARY SEWER MANHOLE WH1EEU>IAIR RAMP E SE ILSI IE IL47 N WETLAND RAG ASWU 50' NWETLAND BUFFER If N AWKALT NIL IC14 Wi C8 IYPE I •at unLffy!V—ThtXE AESM RN 2M S 14.12 DATE 05/12/2005 ' -........._._L'p fE SGWF ... ^ SU PK WL m 146,96=18 BN 17.06 TARGET DEPTH TO TOP OF DEPTH TO BUT OF PIPE CONDUIT suloAmo E 1.2 HUB ELEVATION CWMMAPOWSMACOEN 2_5w POTHOLE 1) UTTIM UTjLrrY IN INCHES UMM IN INCHES SIZE IN INCHES PIPE MATERI& amm IL90 FEEFX calm 6g. 33 FIT POWER 42'P2 POW 41* 0. (2)8'(2)4' PV 17.70' ROCKY 4 PVC 18.12' ROCKY P3 75iff_ 44* 71 2 * 24 PVC 1&16, ROCKY T1 TE �64 WIDE CDF DUCT 1&44' ROCKY 51" 25 WIDE 7�jr'DUCT 1&-47— ROCKY I - T2 25 30 54 25 WIDE CDF DUCT 1811' ROCKY GI 39' 43' 4' PE 1&.31' KY ' F G2 39' PE 18.29' ROCKY UND AVMUE SW FMW LEAD IN TXX — — — 2504.7t bi IF III IN CONCFETE DOM 1017.10' FMW TACK N LW IN_mwfim IN ca MMLKW.Wo O.r]N,Q%z f0111D iXX X LD0 N CMCWM DOWN ary OF RENIN MWIMEW NO.1881 oX w am crTy of Mmm muma EUTOM 2D=FM in 1361. 01V010M 21M FEET NE 1/4, 91 1/4, S 25, TWP 23 N, R 4 E & NW 1/4, SW 1/4, S 30, TWP 23 N, R 5 1, W.Y. SW 34TH STREET 05-18--05 CITY OF CULVERT IMPROVEMENT PROJECT _LL RENTON FIGURE 2 — Planning/Building/Pubfic Works Dept EXISTING SURVEY 05-757 NO. REVISION BY DATE APPR MAP 1 1 1AHNINI v� n. ' w 12'WATER PSE POWER DUCT SIDEWALK PSE 4' GAS Ot CMP CULVERT 8' SS ' a QUEST COMMUNICATION DUCT ADWAY oeo 00o Oo i r U W SECTION A n SCALE HORIZ 1'=5' — 9 VERT 1 =5 J a w z r z t I O t ' U Z K rn 0 0 1 � E n 0 n 5 2.5 0 5 10 Scale Feet N am CITY OF SW 34TH STREET d-t 6 - � CULVERT IMPROVEMENT PROJECT eao REN TON FIGURE 3 - _ DAM Punning/Building/Pubic Works Dept EXISTING SECTION NO. REVISION BY A-NNNNAA j!* Cn CL B CL IL OMq AW C4F FIG , 0 Sim Aw gwu cokm r14T � RI'GBR OO'�CREEK TRAIL RECONSTRUCTION NE WNGWALL IMST 1S, RM MAIN 0 'u-2TAffy ZOL."?=w 0T LO CUT wry Loff FILU IINEW J EXIST SD —..... ... ... CUI FW W/ 0-(FR k,w —NEVWA4� C)", .. .. RELOCTED . . . . . . . . . . 7 awl .. . . . .... .. . . . .. .. .. ..... . .. .... ... . .. . .... .. .... .. .. SEWER,A SEE SAFIGNIURETARY 6 . .. . ...... .... .. .. ... .. .. .. .. . .. .. . . . .. . H . .. . . ..... . .. ... . .. G . .. . . . .. . .. .. .. ... TWO 30 WIDEx7' HI ... ... .......... . ... . ... .. . ...... .. .... 7 RTS .. . . . . . .. H,,15,ASiNS-%' .. ... .. .... . 3 AT OAD Low, .... . ...t. . . . .. . .... . . ----? FIG 5 ..... . ... .. • .. .... If 7......— SS.. .. .. . . .. .. . . .. ..L .. .. ...... . .. . . .. . . .. . . N W . . .. .. .... .. ...... . I.:...:.:. :.' . . ... . . .. . .. ... . . ... . . . . .... ... .. . . ....... . . . . . . .. . . . .... .. . .... ...... TO * *" ,I,* ,I I.- .. .... . :,s,� CATCH BASINS'.. . . . ... —swew s� . ... .. .. .. .. ... ... .. ...... . .. . . . ... . ..... o . . .. .. .. . ... . . .. .... . . . .. . . ... .. . . . ... . ... . . . . . .. ......... .LIMIT OF ROAD RECONSTRUCTION . .. . . . . . .. . .. . . . . . . . . . . . . .. . ... .. . . . . . ........... .AT RPAR LOW POW to . ....... . LIMIT OF ROAD . .. .. .. ... . . .. .. .. . . .... . . .. . .. ... .... ... . . . .. .. .. 7 .. . . .. .... .. ... . . . . .. . .. . .. . . .... . . .. . .. ..... . .... .. . . . .... . . . . .. .. .. . . ... . ..... .. . ... . . .. .... . .. ... .. RECONSTRUCTION . . .. .. . .. .. . ... . . . . .... .. .. .. ..... .. ... . . . ... . . . ... ..... . ... ... .. . . . . . . ... . . . . .... . . .. . . . ... . . . .. .. . .... .. . .. . . .. . . . . . .. . . .. . . :7 L) T D N1. 1 �8 7 .. ....... ....... H .................. ....... LC) ....................................... 0 l i it lit 50' WETLAND BUFFER—"""" SW WINGWAALL A, 1 it SE VONGWALL UMS—Mfml I-U'111�"' ,F N rill ' m I i ;� 4 xatk re I SPRINGBROOK CREEK TRAIL 'HIS SURK,'REME:ZV-S 7-1-T Ta- ,PAP�?*K FEA.77JRz AS -,HEY Ex,�SIZD iN 50��AS OF APft 211, 6X-11 x '�,ry � II .'•.•_���.�,.«.:�fl i ; � I� I � I 1 { f I f � 14, � j 15 0 15 30 Scale Feet NE 1/4, SE 1/4, S 25, TWP 23 N, R 4 1 & NW 1/4, SW 1/4, 3 30, TWIP 23 N, R 5 E, W.V. z CITY OF SW 34TH STREET =15-05 4 RENTON CULVERT IMPROVEMENT PROJECT M FIGURE aw PIanning/Building/Pubric Works Dept ALTERNATIVE 1 PLAN NO. REVISION 13Y DATE APPR V� JAI-ININININIAIA, PROJECT NAME dnupcharoen Nov 21, 2005 - 1:48pm - R:\Seattle\001159 RENTON, CITY OF\11-01021-10000 SW 34TH CULVERT REPL\CADD\F1G5-ALTI-SECT.dwq PPP-SS-TTTT BVC STA 12+27 EL 18.63t, MATCH EXISTING VPI STA 12+52 EL 18.41 EVC STA 12+77 BVC STA 12+80 UROW EL 18.98 OZg`- STA 13+00 A cm 0� N �m 0 0 F,- VPI STA 13+15 C o m m pm r Z EL 19.68 o m c CJ m m m 0 CDm ; i C) O o n Z SW 34th 5� N Z .Z'1 III III 0 o m 11�III m c� o n m m BVC STA 13+50 Fn EL 19.68 rr L m N � Ip If 1� ROW m z o z m g VPI STA 13+85 c� r� EL 19.68 � p g8 c I I Z STA 14+00 Q c� 1 � N EVC STA 14+20 E._ EL 18.98 E. y ;;U n_ BVC STA 14+28 fTl EL 18.82 DO 8 r VPI STA 14+53 C � EL 18.32 m m II (� o_ c 1 T m I n�G)O-I o D m m o z �mK U)m cn z m EVC STA 14+78 EL 18.45t, MATCH EXISTING D ° m n Z o Z z R D y b D NOTES: 1. HORIZONTAL DATUM: NAD 83/91 VERTICAL DATUM: NAVD 88 ON AS-BUiLT DRAWINGS d 2 PROVIDED BY INVERTUTILITY THE CITY OF RENTON. INVERTS WILL n- BE FIELD VERIFIED PRIOR TO 30% DESIGN. d 3. REMOVE EXISTING SANITARY SEWER PIPE AS REQUIRED TO INSTALL NEW CULVERT CROSSING. PLUG END OF REMAINING PIPE WITH CONCRETE 4. NEW SEWER PIPE TO PASS THROUGH NEW STORM DRAIN MANHOLE WITHIN DUCTILE IRON PIPE. U W a a I I >Y IX SDMH RIM 18.16 IE 74 Ig NEW SSIE MH EX SSMH IX SDMH SEE 3 I .._ _ _.._ %. f RIM 19.04 RIM 18 Lil .14 IE 9.44 Z\ IE N 14.6 (EX IX) CONNECT IE S 14.62 j ' TO IX W IX 8' SS SSMH € : 1 IE IN14.59 (IX) IX SDMH Q i IE 10.15 IE 9.26 ce - — _ — _ — _ NEW SSMH 32 LF 8" SS — — _— — 15 — — ' a: ROW E 12 0 40% S EXIST 60" CO . NC STORM l 300 LF 8" SS S=0.40% -- - ij 300 LF 8"SS S=0.40% 165 LF 8' SS S=0.40% NEW SSMH ' $ NEW SSMH — — — — IE 11.37 ,. IE 13.35 TYPE A CURB AND GUTTER S.W. 34TH STREET NEW SSMH 9. 6 — _ —W _ S I �;,• .._._ - f ;..�.. �...._.._......_........_.__........�....__._......_.._......_...-.....�_....____...W....-.--.... — _ _ SEE NOTE 4 _ NEW SSMHIE 14.55 W. ABANDON x I I I ? i IX SS NEW SSMH I I i IX SDMH CONNECT TO EXISTING G 3 RIM 20.40 EX SSMH IE 10.75 o II I j. IE 9.51 IE 10.86 1 I PLAN SCALE: 1'=40' N a a dE a t 40 0 40 80 Scale Feet x w- �° SW 34TH STREET �s-Ts-os ® l-40' n© CITY OF v`.. CULVERT IMPROVEMENT PROJECT RENTON FIGURE 6 a a® �� DATUM Planning/Building/Public Works Dept SANITARY SEWER N0. REVISION BY AlEF-1111 RELOCATION A-NNNNAA Lu 50' V&LA4_,Q I WETLAND BCqPU DARY I I WETLAND M3W AW�'V BOUNDARY R 11r1#*ISM 0&0�OMW kWfER 50' WETLAND BUFFER amov Tar frj1NW JININGAU G8R0OK CREEK TRAIL... ► SPRIN RECONSTRUCTIONS rtX C3It .6 0 uwmy 21WIR C��w OF mar)mur wry Lpff 4� h�"! WiNGW LL EX IT 36 SO C FLUSH Ej 9 60" STORM DUN, a FLL)SH WY NiEW.-WALL-, • h9W WALL F, Wn'Aw PAC L cl LA W, W, zpax ,asr RELOCATED SANITARY ==F:- t 17 SEWER, SEE FIGURE 6 .. . . .. ..... . . .. . . . . . . .. . . .... . . . . . . . . .. .. .. .. .. ... .. ... .. .. .. .. . . .... . . . . . . ... ... . . . . .. ... . . . . . . . . . . .. . . .. .. ... ... . . ...... . .. .. .. .. . . ... .. . . .. . . . .. .... .. ... . . . . . .... .. .. . . . . ... . ......... .. .... ... . .. .. . ... .. .. .. .... . .. . . .... . .. .. .. . . . . . . . . . . . .. . . ... .. .. .. ... ..... .... ... . . ... .... . .. . . . . . . . . .. ..... . . . .. . . . . . . . .. .. . . . .. . .. .. NEW CATCH BASINS AT ea xX P NEW CATCH BASI b.. . .... ... . -'.ROAD LOW MINT . .. . . . .... ... . ... . ... . . .... .. CULVERT ... . . . * .. . . . . .. . A . . . . . . . . .. . . .-AT ROAD LOW . .. . . .. .... ... .. .. . .. ... Imo, . .... . .... . . . . .. . .... . . .. . .... .. . .. ...... . ... . ... ... ... . . ... . . .. . .... .. .. .. . .. . .. . .. .. ... .. .. . .. ..... . .I ... . . .... . sw W?�n IAM�r .....i...�..Ss 8 . . . . . . . .. . .. . . .. .. Y * *, .. .. ... .. . .. . . . . . .. . . . . I. ...... . .. SS-- . . . ** .".%,. .. .. .. .... .%I...._. . .. . . . . .. .. . . .. ..... . .. . . .... .. . . ... . . .... . ... .. . . .. . ..... . . . . .. . . . .. . . ....... . . . . .. . . . . .... . .. .. .. .. . . . . .. .. ... . . ..... . . . . . .. .. ... ... ... . .. .. ..... ........... . ..... . . ... .. .... . .. . .. . .......... -RELOCATED ..... .. ............ . .. . ::.47 .... . .. .... .. . . . .. .. ..... . .. . . . ... . . .. . . .. .. .. . ... . . ... . . ... . . .. .. ... .... . 3r... .. .. ......... .. .. ..... ..... . ... .. .. .. . . . . . .. . .. . .... ... . . . .. ....... ILIMIT ,.... f ... ... . . ... . • WATER OF .. . . . ... . .. . . . .. .. . .... .. . . .. . .. ... . . . tt� .'.' 12' .. . . . ... . .... .. .. . . ... . ... LIMIT OF 1OA1 . . . . ... ..... . . . ... . . .. .. . . .. .. ... .... . .. . . . ... . .. ... . . . .. . . . .... . . . ... . . .. . . . . . . . . . .. ..... .. .. . .. ... . . . . .. . ... .. . . ........ . . ... . . .. .. . . . .. .. . . . .. . . . . . . . . . .. . . . . .......... .. .. .. .. .. ... .. . RECONSTRUCTION ROAD . .... . . .. . ... . . . . ... .. . . RECONSTRUCTION . . .. .... . .. . . .. .. .. . . . . . . . . . .. . . . . .. . . . .,.*.*., . ...��z. .. .. . . . . . . ...... . .. . . ... . . .. .... . . . .. . .. .. . .. 7 J, PAW WER A" aC SW WINGW N SE WINGWALL WETLAND N BOUNDARY . . . ... 50' WETLAND BUFFER -HIS 5LIRsr NE M;I_XRA?^irC FEAMPE'S AS VICY EXSM17 a4 S;1E AS''.F APRX 21, ZCV6- SPRINGBROOK CREEK TRAIL w,20111� 40 15 0 "iIDAT A41_V.441. WF OW tC� )BOUNDAR 'NJ N WETLAND KIN C _TY 15 30 DRANAGE ISTRICT Feet ROW Stole S M, N, P 4 9 � NT S'g 1/4, IS 30, T*. ' Im,, N. R 5 9, WAW CITY OF SW 34TH STREET _4 RENTON CULVERT IMPROVEMENT PROJECT AN CAD FIGURE 7 I DANM Planning/Building/Pubfic Works Dept ALTERNATIVE 2 PLAN NO. REVISION BY DATE APPR A-NNNNAA Z 50' VC 150' VC 50' VC X U x a � ~ (L .r rn , r- Ln + + m + d O Z + N N O "I CDu7 'i'1 N N r N CDr N O ^ N ^ N to ) Q 00 W Q H r F V7 M O N � !% cD a0 LO N a0 F- F— N p N N N cj 2 N W _ N U U J > J H a_ J 2.3' AIAX GRADE RAISE ; E J > J J H > J mu '� 7 W W m W N > W N W m W ] W N 4JJ W +2.0% —2.0% w ISTING GRADE a a TEMPORARY TEMPORARY CONSTRUCTION CONSTRUCTION DIVERSION PIPES EXCAVATION SPAWNING GRAVEL FOUNDATION MATERIAL L SECTION A SCALE: HORIZ 1'=10' FlG 7 VERT 1'-10 a v W I m U Q� R W a: r z PEDESTRIAN L GUARDRAIL RELOCATED WATER 3 ' 3 EXISTING Q SW WINGWALL SIDEWALK I GRADE g SIDEWALK i NW WINGWALL o �CREEK INVERT I RELOCATED GAS U RELOCATED COMMUNICATION DUCT BOX CULVERT BASE �—RELOCATED ELECTRICAL DUCT 8 z V) SECTION SCALE: HORIZ 1'=10' FlG 7 6 VERT 1'=10' [V 8 10 5 0 10 20 Scale Feet N> O woe o.i c /ice CITY OF SW 34TH STREET �t 5-05 CULVERT IM ROVEMEN PROJECT CAD RENTON FIGURE 8 u DATUM I Planning/building/Public Marta oePc. ALTERNATIVE 2 v'c NO. REVISION BY DATE APPR SECTIONS A-NNNNAA NOTES: 1. THIS FIGURE SHOWS A SCHEMATIC PLAN TO TEMPORARILY Lu DIVERT FLOWS IN SPRINGBROOK CREEK. FINAL PLAN WILL BE DESIGNED BY THE CONTRACTOR. X Li I. 0 I& I 50'TLANDD 50, WE 0 BUFFER 0. r WETLAND BOUNDARY WETLAND 48' DLA TEMPORARY BOUNDARY DIVERSION PIPES ttt FLOW FLOW d -.7. TEMPOPARf- TEMPORARY ........ ..... ....... COFFERDAM .... V ................ ............. WERAN .............. WETLAND 50' BUFFER Eb WET LAN a BUFFER PLAN SCALE: 1*=20' Z, 7W6 RSPP,-5 7*157 rHE 6-15-05 A3 711EY FX,*j�-,EM it Sf X AS OF AARE. 21, 200, l'-10, CITY OF SW 34TH STREET RENTON CULVERT IMPROVEMENT PROJECT rm 20 0 20 40 FIGURE 9 1"=20'-O' Planning/Building/Public Works Dept TEMPORARY DIVERSION PLAN IME Aoocw"iy Scale Feet NO. REVISIONffy DATE APPR A- NNNNAA rr rr r �r air r r ■r rr rr ar r� rr rr �r tr r tr �r D C tOp..so' t I+ ' q DIMRRY ROCN _ NIC�El----77Z CONCRETCLASS B l T 72"4 RVE 24.41 LOW 72" 72" 7W NEW 'tares SECS ION ' - W NEw NEW HEW nEw f�B 72•METRD `S�3l �W.9-4--f-6-C TO t-ML9 Sl D 3 VALLEY PARKWAY M,tfti, , 3 s _- S.W. 34th ST. L'B PIPE HEADWALL SCALE IIN°•1-0 PER PLAN B-9 WSDOT STANDARD PLANS -1- - - 77F.... .... r 1.. J r - - I _ f - - - R L41E9 ., __ _ _1 _ I II ENKomirr i' r DRM PIPE HEADWALL _ - — mm W .. ... . .. i ... ..: I .. .. i - - - - .. ... I orb L ..LL S..00R. .. .... .. .... .. .. ...:... :... .: .... .:.:. . I} O R1.OWRRY ROCK 2 .. o ..... ...:.. .. T S O I _ _. :_. ... -- SPRINGBROOK CREEK I ' I . .'.' I ._, x Ra,AwwwAAl + y�: RB: I I D CULVERT DETAIL I I & Yam^ �:lae - I' ALL ITEMS SHOWN EXCEPT QUARRY H ARE LUMP 7Lw BID. ::I OF R 6 NT ON _. __ _..... ..___.... .r___. —.__ _ __T— ____ .. .. ..... ..... ... I. � ! 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TYPE 4 CURB B OUTTER Of, A W N - ._• ..—. .. ..._mow . ...... ............._.._....--w ___ __--._—M ..__. ----. .._-w--. -...._... _— __--_ — _ — _ _ _ 1 '' O' le•a.l O AE_plT. -v PIPE, vat K PLU[ a r Y na m e L tz'slue n E5 TKv.a Si 9 O5 I 12i00 15+00 14+00 15+00 16+00 17+00 1e+00 19-.00 20+00 21+00 22+00 23+00 T Leo u4— 7— t r }.. j i t i 2D -- - - t i 't - -- ( � � �•o. � ': -b. ; 4 1-I"-! -r_._ 1 - -f-{ �1 6RMR.'_.�. • I + � f� I _ —1 i r It � KI T19G� I x see t{ '.. r I EEI r o•.ass 9 ,-i - - t ■ i I i L .0 0 - — -- - - � l — — Wr : -- _- -- - - tt F RENiON __- ! ' �I r � DEPARTMENT OF PUBLIC WORKS ' f — — I { I_' S.W. 34 ST. -- I [AE?IIE oR2{rrt NO81BO3 —I , ',,I �} -Ofi1�.L10f tIAL R4AIC PLAN E I 3 ...tt .. .... ..n na.P2 7 R 1aIVl I� I I♦5 .47 ,.SQaP.seapiq.� r.... at+'t 'F Nx.:r .Vn SM"71K!`N 4!W>Fe` "�? Fc :L... .. � - rTQ4� , ,o. '+,.... a-, „�„' rl•„ ,Y-� ;11 � 1a""�"'9"1 ,1$. p. .C,. i- r'i+.. 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Fin Nr:ftt A6gmblr Incl.de., 9'6e1.Vale M.J..FL.MRb CL wire bn m 12'nnleas nond W-605 9'DL span. all NDa only-.rappw CITY OF RENTON 3N•SMaMa. 3 3.e.Ire.l plan tar olHer rtililie.. OECITYlRT Of[ReINE[N Cent.SlecXMy ynd.r End batting Fft 6. fonlacl Clly al Penton lay... nsl.urnon 11/c•w N d 9ia.at in._9 p.ta.l6 wa.R na...n. S.VV 34 TH ST „n _ 9N. ORI INDUSTRIAL PARK a. la'9a� v 1 '�A.nleMr Mewen: � r• c a%n6nu DIVISION It WATER PLAN Itns[ fe. .ee n C.n..v I.CIIOMNI Irod r1 IIM MGa.a[ .. x.IRdNn Mi I•va..a 9rFaD _ .a...............,..........s.,. .....vn a.... �F— y—r Ir r `°. -- 9Q-16 r: ' No. 1 -SW 34th Street, facing west from culvert crossing f/h No. 2 -SW 34th Street,facing east from culvert crossing City of Renton SW 34th Street Culvert Replacement Field Reconnaissance Photos Wes. } '_.�• ,r • • • • • 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 Y Prepared b : P Jones&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: ' Jones &Stokes 11820 Northup Way,Suite E300 Bellevue,WA 98005 Contact:Andy Wones 425/822-1077 May 24,2005 1 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 ' Chapter 2. Methods ................................................................ 1 2.1. Waters and Wetlands.............................................................1 ' Chapter 3. 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 Conditions ............................................................4 3.3. Stream Reconnaissance........................................................4 ' Chapter 4. Regulatory Issues................................................ 5 Chapter 5. References............................................................ 6 1 1 1 1 1 1 May 24,2005 List of Figures Following Page ' Figure 1 -Regional Vicinity Map of Project Area.......................................................................2 Figure2. Site Drawing...............................................................................................................2 ' List of Appendices Appendix A. Corps Data Forms ' Appendix B. Ecology Wetland Rating Forms 1 City of Renton H ' Chapter 1 . Introduction This technical memorandum describes a wetland delineation conducted for the City of Renton,along Springbrook Creek 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 2 ' :; s" Vie•. {+. �t x '`;" Park � �i F(wtbri \ - — L ;1li I tall Black -RI i 1 9 8 SMurn 'no Ste - +, 34th street s• 1 \V. ^ry aae P 46 ' r.PER. atrcenter I ti '..` I � �•� r� ,..e.- ff II a � s � 4'`rc ti JKt tB. Q � _ ' � - __-.. � � �� � � .✓tom S t �`. �. 25 ` y ;Tukwila —'-'_+ r',J� '•f i I �_.__ fir. pY- /( =_'°/r %�r� �)•� 56. '� _" AV I ' '. / 4y � tit• �1 !z _4 c {� } n. l71•d l Reurorr — IL qsu . ' 36 ! 1 . .... a ! /� :43 � I t ��� I ..• t e�.T SY 4 '•'S . ° t t ° ° N j _i SVt15 y' �•. )� .. —•� , ~, , ! WASHINGTON Source: USGS 7.5'Quadrangle-Renton; TerraServer USA-Aerial Photo Date:6/13/2002 1 t N • ' U 1 J Miles Y V _ v '• H 0 0.5 1 t 111 ' Map Prepared: May 2005 I x �5^ Jones & Stokes Figure 1 - Regional Vicinity Map of Project Area ' SW 34th Street Culvert Replacement Project E` THE CE ENTER OF INIIE C`I'RS P EECTE D iN 5'p THE NORTHEAST OF THE SOUTHEAST OF SECTION 25, TOWNSHIP 23 NORTH, RANGE 4 EAST AND CASE 1 34Ix TREET AVID OAK DALE AVE SN. UFTY OVATIO DATA BASE 1U V FEE N9L5"`° THE NORTHWEST OF THE SOUTHWEST OF SECION 30, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M. j ;ONTROL DATA J.S.�U+ID#FEET. CITY OF RENTON, COUNTY OF KING, STATE OF WASHINGTON b4A2�� 3 j I SSM" .I RIM 19 22 IE E 1354 g j E A 3.D ttt # CHANNELED I#£#n ASEi PN NAIL AT FRUNI OF'NFU AT N w {{ CORNER CONCRETE DRhEwAI L Ibfir9206ND .SE 1.235355i%0, ELEVAt ON 1112'EEt ' >' NORTH NAEPoCNI DATUM 83 91.HEAD NOR'}I 01'35'48'FAST BEfw'EQ!AgNUYENfS AT THE INfERSECIION OF LEND AVQHIE 2RIM ACE E I /:� ME W11766 SW AND SW 3OTH ST(NOT OPEN)AND LIND AVENUE SW AND SW 23RD ST(NOT OPEN). Pl CONCF.ETC ASPHAL'; ?t £ C. Sol 155,'jam 1 § ASPHALT _ vvSS NORTH NAERICAN VERfNY1 DATUM 88.HEED CRY OF RENTON MONUMENT N0.1861 AT THE INTERSECTIONS OF LAND AVENUE I SW AND SW 30TH ST(NOT OPEN)ELEVATION 20.00 FEET AND MONUMENT NO.1551 AT LY83 AVENUE SW AND SW 23R0 ST(NOT WETLAND BUFFER (50 FEET) CASE EL Is,6] 1 q I ( ELK OPEN)ELEVATION 21.32 FEET, BALE EL S 9 ;1 I t x A OHA 811r1: TOP NORTHWEST BASE BOLT OF LIGHT STANDARD f126 FEET FAST OF THE CFlTT13JNE OF 5(MtplCBROON CREEKconcRETE '° \ I s. r- P Z s ON NORTH SIDE OF 34TH STREET SOUTHWEST. ELEVATION 18.92 FEET e }} gg }} R 7 H 3 3 7 1 )t€ WETLAND BUFFER (50 FEET) DNA BMj2: CHSEM SQUARE AT SOUTHEAST CORNER CONCRETE TRANSFORMER,±175 FEET WEST OF SPPoNCEIROOK CREEK a Ecc CENTERLINE MO 12.0 FEET NORTH of BACK OF WALK ON NORTH SIDE SOUTHWEST 3,VTH STREET. ELEVATION 21.10 FEET y y _. "ORN """>I'ORN �,w=f4'ORN �- I g. .�1 T S' TS '`t./� •` �.waA :.,.: /_ �� � _� R I '_� ' �2 � z ) €I�€r�/ �'�++�� �•� � TOPOGRAPHIC MAPPING NOTES: THE MAP SHOWN�� S •""', .„ ""` COMPLETED ON APRIL 2211N,2005 IS E ALL�TDEW UTILITIES OF A SHOWN HEREIN WERE FIELD TIED AS A RESULT OF A UIC SURVEY BY DUANE HARTMAN&ASSOCIATES.INC.TILITY / I g S L > mYl9_i5 -•», _ • -«.. PAINT-OUT DURING THE COURSE OF ANTE FIELD SURVEY. DUANE F4YRIAIAN k ASSOCIATES,INC.(DNA)ASSUMES NO LIABILITY IE w 1189 - -. FOR THE ACCURACY OF MM PAINT-JUT. DNA ASSUMES NO UABILRY,BEYOND SAID DATE,FOR ANY.RE SURFACE WERAND 1 c ( E HE 1153 FEATURE MODIFICATIONS OR CONSTRUCTION ACTIVITIES THAT WAY OCCUR WITHIN OR ADJOINING THE PERIMETER OF THIS SURVEY. .-.,T,...,,..,». .•--�I-»-k- WATER 5 RFU ACE I : m '' c-, T x fj y ft 1230s CONTACT DFA(425/483-5355)FOR SITE UPDATES AND VERIFICATIONS. 11-00 FEEI > 4� 4 -- ..«.,.�s>g..-•^.•,a.- -^^^,..,,, AN o+/,9/loos I I s IYL. L` A WERAND 2 LEGEND . .,...,.,..� 'SP-3•��10�_ R..�, � .. ��. �- •_�,�� :"`"'�..��Fy,�-d.j�-__t/ ROAD CENTERLINE a MONUMENT IN CASE IE62 } 72• STORM CULVERT �"";( � --_{m,»..x,;,;>____ _ r ) ROAD R/GHT-OF-WAY PROJECT BENCHMARK 10 +....>w....> ,,....>..... .-.-..•-. i•C 30' 0�' j12" iOFu CUIVERi I' E....,.. .....,...�.«,,,. ' ..,,... SP-8 BUILDING X PK CAL("`^""`M wAIER SURFACE 1103 FEE' r >�a f II ?, f"E=1.9, � �•""°A •� �„�.« � ON 04/19/2005SPF "T1E 8.1 « _ ClRD! wATER SURFACE IJ.9]CENTFENCEE R®M AND CAS t " gx " 72 CMP 51'JRY CUIVER ,,,€ Is F` -�� AT 2'2D P.Y.ON DA/13/2D°5 .. ..-...«. .. �..."..�. CONTOUR INTERNAL(2 FEET) CULVERT _ �� •" T '72'YP STORM CULVERT r »r, E 20N _,_ _ €I4 I ) E s34 /"'�°^'- .» ' 'm CONTOUR INDEX(10 FEET) STORM IXiNN CATCH BASIN �•> "`== `. I � !3 SrCFN ORRW -�' IE.122] ------ _ Aim" _ WEIIAND BOUNDARY STORM DRAIN CLEANOUT ` RE' T/ 4�17«. `VR t 11�� 1s . . . . ( F� ce nRE ""'«--• WEIVND BUFFER 50 STORM DRAIN MANHOLE IE N 13'fi i BI.OG BLALDOK: CONIFER TREE c� ,«.. w M,« WL t35J e� -6 J y Rw 7,47 «,-- Clf CHAIN LINK FENCE DECIDUOUS TREE BAT I54 i ( IE SITS 1 W '8 N ASPHALT 1R Z P € TIN Z.i CON 323 IRAFOUND REB+R AND CAP OS'SOVMC BOLLARDS j j I «�: M�> CONIC CONCRETE SIGN 1 . •,,:.."«,"-�"'„„""' 2,p�"� ,,,,.,..:.. .LSE« 23> _ PI RIM a.1BOT ASPNur TPA -.W.•�.m. CMP CORRUGATED PETAL PIPE POTHOLE ^o SE PN 11 ft O. x.SEE P' NAIL CASE EL IBBA ) vaor a.74 SANITARY SEWER MANHOLE j AT NE ENO A PHALT Foor „ 4`� __per N 167135.7343 SCALE �f - EDD E)TTRUDED CONCRETE CURB A_ + Li Cl 169A I PATH NEAR BACKOF WALK ��� E 1.235.A45.SBSr J A N 166966 GOS , I � _.,;,,, ELEVAi ON 1564 FEEI ORN OgyMEM,ti UTILITY POLE WITH LIGHT _ • •�€I� I 2 C 295.541 8263 S w / -T�--SSYH - .......... • • ' i • / ) 4 o�ti ELEVATION 1ss FEET € 'P��ASPHx-r_'� 10d, c OFiVI ORDINARY HIGH WATER B-RV �,•I • • .._•- 20 LIGHT POLE I''"•"'"�^- �K__.p, K s 1 637 PVC POLYVINYL CHLORIDE PIPE WATT HYDRANT WERAND BUFFER(50 FEEi) k CNANNElED4 ( WEiIAND BUFFER (50 FEET) SP SON.PLOT WATER VALVE CONCRETE SCALERMMI13'936 1 I ¢SE Ss pg WHEELCHAIR RAMP .,...- .e..„ m..i IE N 130 ASP"LT I ! SDMH STORM DAWN NAEI90lE ' .a.....A.".-.M.y,„,�........>.µ«„m„.Y CHMrFELED I E£ d� e';A ( SSM -, ''sr .3,x 's .. SSMH SANITARY SEMIIt MANHOLE r WETLAND FIAC .oN U. 34 5 {[q$g n,x ASPHALT i m $ § ($T I CM'A4.64 j ¢ { IE 14.62 y1` CB'RE s ¢¢E w 1.s f RIM 20,8511 U11LlTY POTHOLE RESULTS: CONCRETE SCALE { SET PK eWl 6 E.n Igg4CH ELEON 3 IE E 1933 N 16636D.3218 $I i t y w119.35 '>". «^^�^•••^-»-..-•- E 0 5 �II BOi 1705 iiORr DATE 05/12/2005 ELEVATION 19.90 FEET # ' CONCFETF M9� I NU-UR TARGET DEPTH TO TOP OF DEPTH TO BOT OF PIPE CONDOR SUBSURFACE ifiil 9ULTNNC POTHOLE ID UTILITY UTILITY IN INCHES UTUTY IN INCHES SIZE IN ACHES PIPE MATERIAL HUB ELEVATION COMPOSITION Pt POWER 42' 89' 2 2 PVC 17.70' ROCKY ggj( _ P2 POWER 41- 1. 2 2 " PVC 18.12• ROCKY t �t s I P3 POWER 44 71 2 2 PVC 18.18 ROCKY ! T1 TEL 37 64 27 WIDE CDF DUCT 18.44 ROCKY T2 TEL 25 51 25 WEE CDF DUCT 18.47 ROCKY T3 TEL 30 54 25 WIDE CDF DUCT 18.21 ROCKY �FODNO•LEAD IN iACn `^ A0705'50} LIND AVENUE SW G1 CAS 3y 43 4 1B.1 «0. '35 a8Y 2594.76 -N CCRICRETE MAIN FOUND IACh -,FAO IN CONCRCtE �"•'� 0.9 IN:A5E YONUMEIf." t'IN CASE FOUND TACK IN LEAD M CONCRETE;i W1i 3 1. ' RY JF= NINEiII NO '�d61 OJb IN SE t OF RENTON MCNUN[NT SURVETTEn sr �� �� CITY OF RENTON 34TH ST. OWG_0ATE CULVERT WMWBOOK a.K-DESIGN RAAWNm RENTON REPLACEMENT PAGE 13AtuM1 cHI1;KED Planning/Building/Public Works Dept. PROJECT DWG N0. REVISION BY DATE APPR -APPROVED2O` SHT OF_ Figure 2. Site Drawing ' 34th Street Culvert Replacement Wetland Delineation and Stream 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) M 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 8 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. 1 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 1 in the top 10 inches with mottles. Chroma values of ' 1 with or without mottling in the upper 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(Rubus 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 (Solanum dulcamara), poison-hemlock (Conium maculatum), and silver cottonwood(Populus alba). 3.2. Wetland 2 ' Wetland 2, similar to Wetland 1, is a narrow, riverine, flowthrough wetland that runs along both sides of Springbrook Creek downstream of 341h 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. May 24,2005 1 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 mowed/bare 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`h Street, Springbrook Creek is a modified straight, trapezoidal, channel. Riparian vegetation is limited, dominated by reed canarygrass. Several small (1-to 5-inch diameter) willows grow to the north of 34`h Street, between 34`h Street and the outlet of the i City of Ranion 4 ' 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 34`h 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 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 �l l 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 JARPA 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 of Renton b ' Appendix A Corps Data Forms DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) c Project/Site:Stn/ -7! �7 /ilL�`l '`�P VeA'6,t4 Date: O-S— Appiicant/Owner fl 2 County: _K�NGr ' Investi ator s Siate: Do normal circumstances exist on site? Yes No Community ID: P tM ' Is the site significantly disturbed(atypical situation)? Yes No Transect ID: p Is the area a potential problem area? if needed,explain on reverse. Yes No Plot ID: f VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator 1.V W are ru►1GQ,Na CC R yg� H /�7L KIs. 2U(ttCQ dloiGa Z s� G� 10. ' 3_ 11. 4. 12. - 5. 13, B. 14. ' 7, 15, 8. 16. ' •DominantSoecies Percent of dominant species that are OSL, FACW or FAC(excludingFAC- . �• ( Remarks: /��Z� C. � �5 r is-fz/ recK ' HYDROLOGY _Recorded Data(Describe in Remarks): Wetland hydrology Indicators Stream, Lake,or Tide Gauge Primary Indicators: _Aerial Photographs Inundated _Other ✓Saturated in Upper 12 Inches =Water Marks /No Recorded Data Available Drift Lines _Sediment Deposits Drainage Pattems in Wetlands Field Observations: — Secondary Indicators(2 or more required): Depth of Surface Water: (in.) Oxidized Root Channels in Upper 12 Inches Water-Stained Leaves Depth to Free Water in Pit: (in.) _Local Soil Survey Data =FAC-Neutral Test Depth to Saturated Soil: S L`� (in.) Other(Explain in Remarks) Remarks: ��.a ��6'do'lS �J//� /\ /9� �e�r'vf�s / PD'2J� 46 1 SOILS Ma Unit Name Sens and Phase i�i'` ti9y� /^�o ,�� ( )' Drainage Class: Field Observations Taxonomy(Sub nYPI: Confirm Ma Type? Yes No Profile Descriptions: Depth Matra Color Mottle Colors Mottle ' (inches) Horizon Munsell Moist Munsell Moist Abundance/Contrast Texture Concretions Structure,etc. or '/ 19yP3 slat s i i 1 ................_...................._...................................-.................._..............._.........................................._........_.--._...._..............._......._..._.._........ 1 Hydric Soil Indicators: Hlstosol Concretions ' Histic Epipedon High Organic Content in Surface Layer In Sandy Soils Sulfidic Odor Organic Streaking In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils List �Reducing Conditions Listed on National Hydric Soils List 1 Gleyed or Low-Chroma Colors Other(Explain In Remarks) Remarks: WETLAND DETERMINATION ' Hydrophytic Vegetation Present? No (Circle) (Circle) 1 Wetland Hydrology Present? No Hydric Soils Present? Yes No Is this sampling point within a wetland? Yes No Remarks: vl V l (✓ ✓� � R ��dL/ a jLP� (,t/ j r t f �1�f P�Or/ tr•_ / 1 Approved by HQUSACE 3/92 1 i ' DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) Project/Site: j 1^/ ��fY� {�e Iqr/,'/�`9J/� Date: Applicant/Owner: /�� �� County. Invesiigator(s)_ �(✓� 1/t State: IN/ Do normal circumstances exist on site? Yes No Community ID: U Q` Is the site significantly disturbed(atypical situation)? Yes Transect ID: ' Is the area a potential problem area? If needed,explain on reverse. Yes No Plot ID: ' VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator 2-Ru J. (ow ar' ra` S I ' E&u l 10. ' 3. (�� vl0 f,7 Zo /�I 4. /� u ( Gt 1UM: Q. Lftr11 rl � { 12. K ,o ' r )O]Q n w r,�,r'CI� /!�.a r 0 M 13, 6. rl ruM rl aGGtl Q �Cr i�I _ 14, ' 7. 6;? 7 8. 16. •OominenF Soecies Y6NrtP✓!cIlr1 CP � � or .1�1 r'A T 4 Percent of dominant species that are OBL.FACW or FAC(excluding FAG-). 5 /D Remarks: ��'! !l� a 7�t�� �y� i t� Y C� C� V(- ' HYDROLOGY _Recorded Data(Describe in Remarks): Wetland Hydrology Indicators _Stream, Lake,or Tide Gauge Primary Indicators: Aerial Photographs _Inundated Lecorded Other =Saturated in Upper 12 Inches \// Water Marks No Data Available Drift Lines _Sediment Deposits Drainage Patterns In Wetlands Field Observations: Secondary Indicators(2 or more required): Depth of Surface Water: (in.) _Oxidized Root Channels In Upper 12 Inches _Water-Stained Leaves Depth to Free Water in Pit: (in.) Local Soil Survey Data ' =FAG-Neutral Test Depth to Saturated Soil: (in.) Other(F)q3lain in Remarks) Remarks: /\f Lg A yg�;(A 0/e'q 1`ri 1 SOILS , Map Unit Name (Series and Phase): ��' e'i°If f f f %? Drainage Class: r, k t' Field Observations , Taxonomy(Subgr jypj_ Confirm Ma T ? Yes No PP ...YPe.................... Profile Descriptions: Depth Matrix Color Mottle Colors Mottle ' inches Horizon Munsell Moist Munsell Moist Abundance/Contrast Texture Concretions Structure etc. 0- D/1-g- ................__......................................................._.._._...........................................................................................................................--_............. Hydric Soil Indicators: Histcsol Concretions , Histic Epipedon High Organic Content in Surface Layer in Sandy Soils Sulfidic Odor Organic Strealdng In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils List Reducing Conditions Listed on National Hydric Soils List ' ,}Gleyed or Low-Chroma Colors Other(Explain In Remarks) Remarks: /I✓ <<" S / r HGt /CQ�d d WETLAND DETERMINATION , Hydrophytic Vegetation Present? Yes (Circle) (Circle) ' Wetland Hydrology Present? Yes Hydric Soils Present? Yes o Is this sampling point within a wetland? Yes No Remarks: P�o 7' a R 1,✓10 �4/'K('/G��,G,G' GrJ� �✓P f�d/li c� -1�m� �dv✓;�,'a 7'Pd' � / K i✓�._'-,'1�� Xv Approved by HQUSACE 3/92 ' 1 ' DATA FORM ROUTINE WETLAND DETERMINATION (1987 COEr�Wetlands Delineation Manual) Project/Site: Svc 21 S� CIAI UPr-r ��Q/�/?rP�''fG Date: /9'I- Applicant/Owner: / /Z 4 7'-'19PI County: ' Investi�ator(s�: C State: Do normal circumstances exist on site? Yes No Community ID: Is the site significantly disturbed(atypical situation)? Yes AN, Transect ID: Is the area a potential problem area? If needed,explain on reverse. Yes I Plot ID: r �� VEGETATION Dominant Plant Scecies Stratum Indicator Dominant Plant Species Stratum Indicator A 2. 10. 3. it. 4. 12. ' S. 13. 6. 14. ' 7_ 15. 8. 16. 'Dorrvnant Species............................ ._.._... ..............................................................................._........................................... Percent of dominant species that are OBL FACW or FAC(excluding FAC- . a Remarks: pop"r L-1 cc?--e ' HYDROLOGY Recorded Data(Describe in Remarks): Wetland Hydrology Indicators ' Stream, Lake,or Tide Gauge Primary Indicators: Aerial Photographs _Inundated Other *7'Satur-ted in Upper 12 Inches _Water Marks No Recorded Data Available Drift Lines ^_Sediment Deposits Drainage Patterns in Wetlands ' Field Observations: — Secondary Indicators(2 or more required): Depth of Surface Water: (in.) _Oxidized Root Channels In Upper 12 Inches _Water-Stained Leaves Depth to Free Water in Pit: (in.) _Local Soil Survey Data FAC-Neutral Test Depth to Saturated Solt -/�`� �1 C r� (in.) Other(Explain In Remarks) r Remarks: rCa. /BOA f ;✓� �i P! l0W� SOILS Map Unit Name(Series and P r ): , l� ) y x Phase): �J1._ �'"1.1.5 1� '/ , �,�+'r � Drainage Class: Field Observations ' Taxonomy(SuVg?up): Confirm Mapped Type? Yes No ' Profile Descriptions: Depth Matrix Color Mottle Colors Mottle 1 inches Horizon Munsell Moist Munsell Moist Abundance/Contrast Texture Concretions.Structure etc. , , ? lmk> 4�.s" 5E,1t 1 TIT 1 ................-.....................................................................................................................................................-- _.._.........................._......._...... Hydric Soil Indicators: Hlstosoi Concretions ' Histic Epipedon High Organic Content In Surface Layer In Sandy Soils Sulfidic Odor Organic Streaking In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils List Reducing Conditions Listed on National Hydric Soils List 1 Gleyed or Low-Chroma Colors Other(Explain In Remarks) Remarks: ' WETLAND DETERMINATION , Hydrophytic Vegetation present? No (Circle) (Circle) ' Wetland Hydrology Present? No Hydric Soils Present? es No Is this sampling point within a wetland? (Yes) No Remarks: /Z% . 1 Approved by HQUSACE 3192 ' U � HWA GEOSCIENCES INC. �, Geotechnical c: Pavennent Engineering • Hydrogeology - Geoenvironmental - Inspection & Testing TECHNICAL MEMORANDUM TO: Mike G' urt/R.W. Beck Inc.—Allen Quynn/City of Renton PREPARED BY: Lo al o/HWA GeoSciences Inc. RECEIVED SUBJECT: SW 34TH STREET/SPRINGBROOK CREEK JUL 2 7 2007 Culvert Improvement Project 34th Street at Springbrook Creek CITY OF RENTON City of Renton,Washington UTILITY SYSTEMS PROJECT NO.: 2005-043-21 DATE: July 26, 2007 Pursuant to recent requests and in coordination with the project contractor's schedule, Lorne Balanko, P.E., of HWA GeoSciences Inc. (HWA), examined conditions at the project site on July 19, 2007, and again on July 25, 2007. These inspection requests were made by Allen Quynn, of the City of Renton, and yourself, in respect to confirmation that the contractor's subgrade preparation for the replacement culvert was satisfactory for the proposed replacement culvert facility. The initial inspection on July 19th was performed, in the presence of Allen Quynn and Ron McPhee, of the City of Renton, subsequent to the occurrence of relatively heavy rainfall in the preceding few days, which apparently resulted in significant water level increase in Springbrook Creek. This increase in water level in the natural creek channel, as well as the temporary diversion channel, apparently caused a number of pipes or blowouts to develop in the contractor's coffer dam system onboth ends of the completed culvert excavation with substantial inflow of water and mud to the excavation. The contractor's representative (Rick) indicated that the excavation was pretty much flooded, after having prepared the base in native, dark gray to black, fine to medium sand soil to a relatively firm and stable condition. At the time of our observation,the water level had been pumped down to a few inches above base level and a large excavator, operating from outside the excavation, was in the process of removing mud from the excavation base. We advised that unless the sub-excavation to remove mud and softened soil exceeded about 6 inches depth that it was preferable to place additional CDF for the culvert support surface. Otherwise, quarry spalls would be acceptable. Further inspection was recommended and agreed to at a time when the contractor had re- established suitable excavation base conditions. We were again requested on a couple of occasions thereafter to attend at the site for an additional examination of the excavation base. However, rainy weather conditions continued to hamper base preparation efforts, and our next site visit was 19730-64th Avenue W. undertaken on July 25, 2007, in the presence of Ron McPhee and Rick,the suite 200 Lynnwood,WA 98036.5957 Teh 425.774.0106 Faic 425.774.2714 www.hwageoscienceswm ' July 26, 2007 HWA Project No. 2005-043-21 contractor's representative. On this occasion,the weather conditions had been dry for a couple of days prior and the excavation base had been reworked by the contractor. During our site visit(again performed by Mr. Balanko), we were advised by Rick that a clay/silt layer was encountered in approximately the east half of the excavation during base cleanup and that this layer was soft and unstable, pumping readily under foot and equipment traffic. Rick indicated further that they sub-excavated the material to a depth of about 2 feet and backfilled it with quarry spalls to facilitate provision of a stable subgrade that would also allow free drainage. This was topped with about 6 inches of what appeared to be 3 to 4-inch minus, rounded to sub-rounded, river gravel. At the time of our inspection, the topping gravel had been placed over about a 10 to 15-foot wide strip through the approximate eastern half of the excavation, but the quarry spalls at the north end had been left exposed for our observation. Water was observed to be flowing through the spalls at a rate estimated to be less than 10 gallons per minute, and the sumps and pumps at both ends of the excavation appeared to be managing to prevent ponding of water over the excavation base. Medium to coarse sand was being placed, to a depth of about 6 to 10 inches, to cover the native sand/silt materials exposed in the base along the approximate west-half of the excavation, with the exception of a narrow(less than 2 feet wide) strip being left uncovered to also conduct water flow to the north sump. A similar strip of exposed native silt/sand subgrade had been left exposed along the east side as well,but little to no water flow was occurring in this area. Our hand-probing of the subgrade base area indicated that the gravel-topped quarry spall zone was impenetrable and unyielding under foot. The sand-covered and exposed native silt/sand soils were firmlloose to medium dense under foot and could be penetrated with the T-handled probe to depths varying from less than 1 foot to as much as 3 feet in localized areas, but generally less than 18 inches. This suggests that the materials presently exist in their natural state and they do not appear to have been excessively disturbed by the contractor's activities. It is our opinion that the CDF base support layer for the culvert should be placed as soon as possible over the prepared subgrade, and this was expressed to representatives of the contractor and City on site. It was further indicated that the sand should continue to be placed over the entire excavation base,to the design level of the CDF underside, and should be lightly track-walked and back-bladed by the small excavator presently operating within the excavation. Rick indicated that the CDF has been ordered for Friday of this week. It was confirmed that this should be placed directly over the sand layer and a geotextile separator was considered unnecessary. We trust that the foregoing inspections, observations and recommendations meet with your present requirements. However, should you have any questions, or require further inspections,please call at your convenience. 34th Street Culvert Inspection 2 HWA GEOSCIENCES INC. DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) ' Project/Site: > �. .t�I .�i. / j�� 4 rn n Date: y 9 O Applicant/Owner: 1 2 - �rrt County KI/�y lnvesti�ator(s�. V v D L State: / Do normal circumstances exist on site? Y6s No Community ID: ' Is the site significantly disturbed(atypical situation)? Yes No Transect ID: ' Is the area a tential roblem area? if needed.ex lain on reverse. Yes To Plot ID: VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator /o o ,.�ul,u� c�rce�er s � 2. rinida r iS afLJ Vta a�11 10. 3. 11. 4. 12. ' g. 13. 6. 14. ' T, 15. 8. 16. p DominantSoecies i` ite".. i-' /rSi �� ................................................................. --._..._.. ... ..... ............................................................ .. .. Percent of dominant species that are OBL FACW or FAC (excluding FAC- . lJ Remarks: D _.j, r ' HYDROLOGY Recorded Data(Describe in Remarks): Wetland Hydrology Indicators Stream, Lake,or Tide Gauge Primary Indicators: _Aerial Photographs _Inundated Other _Saturated in Upper 12 Inches _Water Marks IN.Recorded Data Available _Drift Lines _Sediment Deposits —Drainage Patterns in Wetlands ' Field Observations: Secondary Indicators(2 or more required): Depth of Surface Water: (in.) _Oxidized Root Channels in Upper 12 Inches _Water-Stained Leaves Depth to Free Water in Pit: (in.) _Local Soil Survey Data ' =FAC-Neutral Test Depth to Saturated Soil: (in.) Other(E)plain in Remarks) Remarks:N t9 ;I /'"//7/ / I r r A �f.: SOILS ' Map Unit Name �//��, l (Series and Phase): f>�J.7J;/ fir, l t( �{�Yyr/ Drainage Class: O/Kz or Field Observations ' Taxonomy(Subgroup: Confirm MaPPS T 7 Yes No.._._................. _..YPe.............. ........... Profile Descriptions: Depth Matra Color Mottle Colors Mottle ' inches Horizon Munsell Moist unsell Moist) Abundance/Contrast Texture Concretions Structure etc. Ze _............................................................................................_.........................................................................._..........................M...._._......._..... Hydric Soil Indicators: Hlstosol Concretions , Histic Epipedon High Organic Content in Surface Layer in Sandy Soils Sulfidic Odor Organic Streaking In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils List Reducing Conditions Listed on National Hydric Soils List , Gleyed or Low-Chroma Colors Other(Explain In Remarks) Remarks: WETLAND DETERMINATION , Hydrophytic Vegetation Present? Yes (Circle) (Circle) , Wetland Hydrology Present? Yes Hydric Soils Present? Yes No Is this sampling point within a wetlarxi? Yes No Remarks: �O� Low ep"d, vto WeYfdlc4' J66V, 1-11--wvkta/f,� 6, / vtVaS/ VC. Approved by HQUSACE 3/92 ' ' DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manuai) r n Project/Site: J�� ) �� �`t_ U///-��'-� --��./ ri+� �� Applicant/Owner: ✓ '� County. ��/�J C17 ' Investi�ator(s�: State: . l . ........... p Do normal circumstances exist on site? Yes No Community 10: ' Is the site significantly disturbed(atypical situation)? Yes N Transect ID: Is the area a potential problem area? (If needed,explain on reverse. Yes N Plot ID: ' VEGETATION ' Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator �0.'3�P 1. Pinar/` a��, C oa CLtJ 9. 2. 10. ' 3. 11. 4. 12. ' S. 13. 6. 14. ' 7, 15, g. 16. ' .....•Doin.ant.Species min ................................................................................................................................................_................................ ..... -- 0 Percent of dominant soecies that are OBL,FACW or FAC(excluding FAC-). G 711 p r Remarks: ���r s 'l q L i'y! jo. . '�/-( HYDROLOGY Recorded Data(Describe in Remarks): Wetland Hydrology Indicators Stream,Lake,or Tide Gauge Primary Indicators: _Aerial Photographs Inundated Other �aturated in Upper 12 Inches _Water Marks No Recorded Data Available —Drift Lines _Sediment Deposits _Drainage Patterns in Wetlands ' Field Observations: Secondary Indicators(2 or more required): Depth of Surface Water: (in.) _Oxidized Root Channels In Upper 12 Inches _Water-Stained Leaves Depth to Free Water in Pit: (in.) Local Soil Survey Data =FAC-Neutral Test Depth to Saturated Soil: (in.) Other(Explain in Remarks) Remarks: /o%�l �ir�,/�, .:r y- 1v� � r. a yti, �/ r`'�' •"emu--; r SOILS Map Unit Name J , (Series and Phase):_ I I 0 Ile r!/r t ZDCt L1 Drainage Class: Go r/� 4,14 Field Observation's ' Taxonomy(Sutjroup)_ Confirm Ma T 1 ............ir .....p ped Yes No..YPe.................................. Profile Descriotions: Depth Matrix Color Mottle Colors Mottle ' (inches) Horizon Munsell Moist Munsell Moist Abundance/Contrast Texture Concretions.Structure etc. ...................._............................................................................................................................................._...................................._......._........... Hydric Soil Indicators: N Istosol Concretions ' Histic Epipedon High Organic Content In Surface Layer In Sandy Soils Sulfidic Odor Organic Streaking In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils List �Reducing Conditions Listed on National Hydric Soils List ' Gkeyed or Low-Chroma Colors Other(Explain in Remarks) Remarks: WETLAND DETERMINATION ' Hydrophytic Vegetation Present? No (Circle) (Circle) ' Wetland Hydrology Present? No Hydrk Sills Present? Yes No Is this sampling point within a wetland? � Y No Remarks: ����! �yL� ��,(f4�'.Cl� Gi•S��'�G/i?]��G?// j/�- i�? b�l_v o,�' (�� � , ' Approved by HQUSACE 3192 ' ' DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) ' Project/Site: �� L�c/V(�� Y�C/Lt Date: Applicant/Owner: f,YL� JI) I�{'�' � County- Do normal circumstances exist on site? ( Yew No Community ID: Is the site significantly disturbed(atypical situation)? ��Yes Transect ID: ' Is the area a potential problem areal If needed,explain on reverse. Yes N Plot ID: r ' VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator 9. 2. �Jr'+'9 f r` 7 / •/I•.�.'/1 J/ /<` F�r �� 10. 3. 11. 4. 12 ' S. 13. 6. 14. ' 7, 15. S. 16. PDominant Species rr .ercent ..................I.................................__............_......_.._.._.............._....._.._..... ...._.._ .............................of dominant species that are OBL, FACW or FAC(excluding FAC- . b Remarks: C�GI" i4 Wiz'El C ��-{��''''�!�,,^_i✓ . i� Or �✓j� �f ' HYDROLOGY _Recorded Data(Describe in Remarks): Wetland Hydrology Indicators Stream.Lake,or Tide Gauge Primary Indicators: Aerial Photographs _Inundated _Other Saturated in Upper 12 Inches — =Water Marks No Recorded Data Available Drill Lines _Sediment Deposits _Drainage Patterns in Wetlands ' Field Observations: Secondary Indicators(2 or more required): Depth of Surface Water: (in.) _Oxidized Root Channels In Upper 12 Inches _Water-Stained Leaves Depth to Free Water in Pit: (in.) _Local Soil Survey Data FAC-Neutral Test Depth to Saturated Soil: (in.) Other(Explain in Remarks) ' Remarks: fo "l! C lc' SOILS ' Map Und Narne ` A (Series and Phase): �/` r(4, <, IIt /©q M Drainage Class: Oo izs'v/ Field Observations ' Taxonomy(Subaroup�: Confirm Ma T 7 Yes No ........... ..................P ._..._.YPe._........... Profile Descriations, Depth Matrtx Color Mottle Colors Mottle ' finches) Horizon Munsell Moist Munsell Moist Abundance/Contrast Texture Concretions Structure etc. LLi 4/ bo a .........._...................................................................----...........•.••.--.---..._..........................................---.....-----..._...._............---.••............ .....__.. Hydric Soil Indicators: Histosol Concretions , Histic Epipedon High Organic Content in Surface Layer in Sandy Soils Sulfidic Odor Organic Streaking In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils Last Reducing Conditions Listed on National Hydric Soils List , Gleyed or Low-Chroma Colors Other(Explain In Remarks) Remarks: �! WETLAND DETERMINATION Hydrophytic Vegetation Present? Yes (Circle) (Circle) I Wetland Hydrology Present? Yes Hydric Soils Present? Yes Is this sampling point within a wetland? Yes No Remarks: Approved by HQUSACE 3/92 ' DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) 'l ProjeW —�� f! i�/�f� .4 (// Date- Site: Applicant/Owner: County: Investi ator s : State: t4j Do normal circumstances exist on site? Y No Community ID: Is the site significantly disturbed(atypical situation)? Yes o Transect ID: �PIs the area a potential problem area? (if needed,explain on reverse.) Yes No Plot ID: VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator �J 2. 10. 3. it. 4_ 12. 5. 13. 6. 14. 7. 15. a. 16. Percent DorrainantSpecies... .................. ........_......................_................................__..................................................................................._...._......_.._....__............... of dominant species that are 06L, FACW or FAC (excluding FAC- Remarks: �d n t h a n v r1 P /r'.�z �• . 1 HYDROLOGY Recorded Data(Describe in Remarks): Wetland Hydrology Indicators _Stream,Lake,or Tide Gauge Primary Indicators: Aerial Photographs _Inundated Other ,,-Saturated in Upper 12 Inches _Water Marks —No Recorded Data Available _Drift Lines _Sediment Deposits Drainage Patterns in Wettands Fleld Observations: Secondary Indicators(2 or more required): Depth of Surface Water: i (in.) _Oxidized Root Channels In Upper 12 Inches _Water-Stained Leaves Depth to Free Water in Pit: (in.) _Local Soil Survey Data =FAC-Neutral Test Depth to Saturated Soll: (in.) Other(Explain In Remarks) Remarks: „l]SS-e"r-r Ct _ - /Y F / SOILS Map Unit Name (Series and Phase): (/ G°�K1R �/r f S,/'�' �0►JJ� Drainage Class: Nnf/ A,-i4,,d' Field Observations ' Taxonomy(Sub�rouo�: Canirm Ma T ? Yes No ................. .......................ppe.d...yP..e.................................. Profile Descriptions: Depth Matra Color Mottle Colors Mottle inches Horizon Munsell Moist Munsell Moist Abundance/Contrast Texture Concretions Structure etc. t ..............................................................................................................................................................................................................._.__.......... Hydric Soil Indicators: Histosol Concretions Histic Epipedon High Organic Content In Surface Layer in Sandy Soils L Sullidic Odor Organic Strealdng In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils List Reducing Conditions Listed on National Hydric Soils List Gleyed or Low-Chroma Colors Other(Explain In Remarks) Remarks: R I'�¢ fig • p°�/` , WETLAND DETERMINATION Hydrophytic Vegetation Present? No (Circle) (Circle) Wetland Hydrology Present? No Hydric Soils Present? Yes No Is this sampling point within a wetland? Yes No Remarks: DD I� C!a��� c✓/ s 1 itq G Approved by HDUSACE 3/92 ' DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE Wetlands Delineation Manual) SIf) L.fJ � n��C✓/J.% Date: ProjecUSde: � '�-j% t`' � I Applicant/Owner: r County. l� Investi ator s : C �� State: Do normal circumstances exist on site? Yes No Community ID: Is the site significantly disturbed(atypical situation)? Yes �� Transect ID: Q ' Is the area a potential problem area? If needed,explain on reverse. Yes N Plot ID: r VEGETATION Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator f�-C9/D/ �c 7_ r >7 3. it. _ 4. 12. 5. 13. 6. 14. 7_ 15. 8. 16. Dominant Svecies Percent of dominant species that are OBL FACW or FAC(excluding FAC- . Remarks: � � �1 P .��.'� �. j:r,. _r h� cat / ` �> ���� �✓fj / HYDROLOGY _Recorded Data(Describe in Remarks): Wetland Hydrology Indicators Stream, Lake,or Tide Gauge Primary Indicators: _Aerial Photographs _Inundated Other _Saturated in Upper 12 Inches _Water Marks No Recorded Data Available _Drift Lines _Sediment Deposits _Drainage Patterns in Wetlands Field Observations: Secondary Indicators(2 or more required): Depth of Surface Water: (in.) _Oxidized Root Channels In Upper 12 Inches Water-Stained Leaves Depth to Free Water in Pit: (in.) `Local Soil Survey Data ' =FAC-Neutral Test Depth to Saturated Soil: (in.) Other(Explain In Remarks) 1 Remarks: r SOILS Map Und Name (Series and Phase): 00a11 1000f Drainage Class: Field Observations Taxonomy(Sut�roup�_ Confirm Ma T ? Yes ._.. PP ....YPe....................No Profile Descriptions: Depth Matrix Color Mottle Colors Mottle , inches Horizon Munsell Moist Munsefl Moist Abundance/Contrast Texture Concretions Structure etc. . 1 __...................................._...............................--....................................----......_.......................... .__.__................ _. ._.......... i Hydric Soil Indicators: Hlstosol Concretions Histic Eplpedon High Organic Content In Surface Layer in Sandy Soils Sulfidic Oda Organic Streaking In Sandy Soils Aquic Moisture Regime Listed on Local Hydric Soils List Reducing Conditions Listed on National Hydric Soils List Gleyed or Low-Chroma Colors Other(Explain in Remarks) Remarks: �® '� r•C _e f , :.y . / ;;' ✓ (2� WETLAND DETERMINATION Hydrophytic Vegetation Present? Yes �Nq:..(Circle) (Cif) Wetland Hydrology Present? Yes q Hydric Solls Present? Yes No Is this sampling point within a wettand? Yes No P 9 P� Remarks: Approved by HQUSACE 3/92 ' Appendix B Ecology Wetland Rating Forms r IWETLAND RATING FORM—WESTERN WASE INGTONV V P1 ' Name of wetland(if known): - C Location: SEC: 36? TWNSHP: T RNGE:-�LE (attach map with outline of wetland to rating form) Person(s)Rating Wetland: Affiliation: r1 Date of site visit: DRAFT SUMMARY OF RATING t Category based on FUNCTIONS provided by wetland I II M-K IV Score for Water Quality Functions 1 - Category I= Score >70 1 Category H= Score 51-69 Score for Hydrologic Functions 4 Category Ill = Score 30-50 Score for Habitat Functions Category TV = Score < 30 TOTAL score for functions , ' Category based on SPECIAL CHARACTERISTICS of wetland I H Does not Apply Final CategO choose the "highest" catego from above ,. b 13' ( � � ) Check the appropriate type and class of wetland being rated. i�VetlaIId� —`�� .«>,M�p '�' .: ..,.. , .: � ^^•u=ems�-W��IaIf.(I;JCIaSs:X�c'�°��^ �+KP�^�•,. Estuarine De ressional Natural Heritage Wetland Riverine Bog 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. , u Che+ l� sl faretlaitdswz s at Need' pecl 'roteetx�tinj �d YES NO` SP 1. Has the wetland been documented as a habitat for any Federally listed Threatened or Endangered plant or animal species (TIE species)? 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? :P+ For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. , SP3. Does the wetland contain individuals of Priority species listed by the WDFW for the state? SP4. Does the wetland have a local significance 'to addition to its functions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local management plan as having special significance. To complete the next part of the data sheet you will need to determine the Hydro-Cr eomorphic 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. 1 1 Wetland Rating Form—western Washington 2 August 2004 ' Classification of Vegetated Wetlands for Western Washingbton Vegetated ' Wetland Name: Date: 1. Arethe water levels in the wetland usually controlled by tides (i.e. except during floods)? NO? b 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 tILp topography within the wetland flat and precipitation is only source (>90%) of water to it. r NO L go to 3 YES—The wetland class is Flats If your wetland can be classified as a"Flats" wetland,use the form for Depressional wetlands. 3. Does the 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 $ (2 m)? t NO-1 go 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). Ogo to 5 YES—The wetland class is Slope 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 i 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, if present, 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 r 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. �7�M�Ia�se���Yithi�a.I7elan�ated Wetland:$ounrlc�r ,... �z � Glass to�s�,-rrr Ratnn �.'�q�-, Slope +Riverine Riverine Slope +Depressional De ressional 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 Treat as ESTUARINE under ' wetland wetlands with special characteristics If you are unable still to determine which of the above criteria apply to your wetland, or ydiz have more than 2 HGM classes within a wetland boundary, classify the wetland as,Depressional for the rating. Wetland Rating Form—western Washington 4 August 2004 ' t .§ir wet+.ii s r. k,2 c r ro ,., f�.� •�•-rsSirosM4. ! N"XU�dtc�t��'��t Wet�arld�U21GtIaIl�'tu Inl�� . ��. -' 3a �EBtz% RR 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= 8 Depressions cover> 1/2 area of wetland points=4 Depressions present but cover< 1/2 area of wetland points=2 No depressions present 2oints=0 .r 1 R R 1.2 Characteristics of the vegetation in the wetland:Forest or shrub >2/3 the area of the wetland points= 8 Forest or shrub> 1/3 area of the wetland points= 6 Ungrazed, emergent plants>2/3 area of wetland points=1y6 ' Ungrazed emergent plants > 1/3 area of wetland points= 3 Forest, shrub, and ungrazed emergent< 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? (see p. 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 ' sResidential, 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 I DES a:=multiplier is 2 NO multiplier is I R TOTAL -Water Quality Functions Multiply the score from R 1 by R 2 l 7- Add score to table on p. 1 ' Comments Wetland Rating Form—western Washington 7 August 2004 ���,.,.,�., �`�- Y.s.5`-sv��'`yN'�5 TAT F.5 as .yy,`-� Ct .. � 3' rl ..arts:�- � 'S i�'ai .... ''✓k R � � r�� anc `resliwa �e > ge� �,�,:. � x z < �s�s€s �y a4s��, fy 3 ,�•a m �..� gar x r,.e_.'sapr ,�y� ,a», � +��,e ,. �+.Tr,.a'•b`,Y Yt'" z.s� ood[Lls �,.� Vd�i�ela .•;?•�""bZa3..��� �r,;a,�'�messr�c..;'F-<sas 3s: �'�.,.., ���'f�tAf t „� 3d5���. R 3. Does the wetland have the potential to reduce flooding and erosion? , . < see 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)/(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=;-, ' If the ratio is < 1 points 7,1 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. Forest or shrub for>1/3 area OR Emergent plants > 2/3 area points 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, farms)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) YES multiplier is 2 NO multiplier is 1 ' R TOTAL -Hydrologic Functions Multiply the score from R 3 by R 4 /11 Add score to table on p. 1 , Comments Wetland Rating Form—western Washington 8 August 2004 ' i ,�� .., i n ^ie r .+s z.. .arpysyra '.ad^adisa" x•xwuy "h�a" fKx a 3ry �N.e 4 xe4. � �A Yx�.�.. �.. • ^"t 4 �' � .,y xs 3' .a' '�^.:x•- �P� �a^r.-h Vi ...�. „�,�,� �'�X hank1 }fa# RI1BIT A' ' CIONS 3 Ti;dreafors that weffanict3ons toxpr ode�rnpa ' ,z, :.?r�,s9.,:.:4°?'es �,�.�,r "'✓;< .qs.? ...,z �;ia+�^c�a.F"sF`;�2�N�i'Ysds 31"�'Z_z"�.�.u�`c :r . :-^r,�ga..roz�'z.,p�err� 3•,,�5c°' H 1. Does the wetland have the potential to provide habitat for many species? F 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. o, Equatic bed mergent 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= 1 e oints , 0 H 1.2. Hydroperiods (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 hydroperiods) 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 ,Saturated only Permanently flowing stream or river in, or adjacent to,the wetland ' Seasonallyflowing stream in, or adjacent to,the wetland g J Lake fringe wetland =2 points ' Freshwater tidal wetland=2 points H 1.3. Richness of Plant Species (seep. 75) Count the number of plant species in the wetland that cover at least 10 f. (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 if you want to: 5 - 19 species points= < 5 species points 0 ' Wetland Rating Form—western Washington 13 August 2004 H 1.4. Interspersion 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 include open water or mudflats) is high, medium,low, or none. None 19oints Low= 1 point Moderate =2 points E t- (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 4/ 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 y 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 I/4 acre of thin-stemmed persistent vegetation or woody branches are present , in areas that are permanently or seasonally inundated(structures for egg-laying by amphibians) Invasive plants cover less than 25% of the wetland area in each stratum of plants H 1. TOTAL Score - potential for providing habitat 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 best represents condition of buffer of wetland. The highest scoring criterion that applies to the wetland is to be used in the rating. See text for definition of"undisturbed." — 100 m (33Oft) 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 m (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 50% circumference. Points =4 — 50 m (170ft) of relatively undisturbed vegetated areas,rocky areas, or open water >95% circumference. Points =4 — 100 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water >25% circumference, . Points=3 — 50 m(170ft) of relatively undisturbed vegetated areas,rocky areas, or open water for> 50% circumference. Points =3 If buffer does not meet any of the criteria above — No paved areas (except paved trails) or buildings within 25 m(80ft) of wetland> 1 95% circumference. Light to moderate grazing, or lawns are OK. Points=2 — No paved areas or buildings within 50m of wetland for>50% circumference. Light to moderate grazing, or lawns are OK. Points=2 — Heavy grazing in buffer. Points= 1 — Vegetated buffers are <2m wide (6.6ft)for more than 95% of the circumference /J(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% 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). YES =4 points (go to H 2.3) go to H 2.2.2 H 2.2.2 Is the wetland part of a relatively undistut,ed and unbroken vegetated ' corridor(either riparian or upland)that is at least 50ft 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 1 mi of a greater than 20 acres? ESP 1 point NO=0 points ' Wetland Rating 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) Riparian: The area adjacent to aquatic systems with flowing water that contains r 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. Old-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 D 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 Landscape (choose the one description of the landscape around the wetland that best fits) (seep. 84) ' There are at least 3 other wetlands within V2 mile, and the connections between them are relatively undisturbed(light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads,fill, fields, ' or other development. points=5 The wetland is Lake-fringe on a lake with little disturbance and there are 3 other lake- fringe wetlands within V2 mile points=5 There are at least 3 other wetlands within'/2 mile,BUT the connections between them : ' are disturbed points The wetland is Lake-fringe on a lake with disturbance and there are 3 other lake- fringe wetland within V2 mile points=3 There is at least 1 wetland within %2 mile. points=2 There are no wetlands within V2 mile. points=0 H 2. TOTAL Score - opportunity for providing habitat 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 P. 1 ' Wetland Rating Form—western Washington 17 August 2004 GEOTECHNICAL REPORT t SW 34`" Street/Springbrook Creek Culvert Improvement Project HWA Project No. 2005-043-21 Prepared for R.W. Beck October 14, 2005 U1 U111", HNVA GEOSCI E NCES INC. u`1'f1,1 HWA GEOSC1 E NCES INC. �� +';etr,e.��;a ut' f��ni t t'`�rt� .o.r;� c'�:.4;�°• C;ecurnsart�+rr7,�rr,a; ��r..�:.; . lrr j�.ti< � r 7e.�tru�� October 14, 2005 HWA Project No. 2005-043-21 ' R.W. Seek, Inc. 100 Fourth Avenue, Suite 2500 Seattle, Washington 98 1 54-1 004 Attention: Mr. Michael S. Giseburt,P.E. Subject: GEOTECHNICAL REPORT SW 341e Street/Sprinabrook Creek Culvert 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 GEOSCIE.NCES INC. ' Lorne Balanko, P.E. Geotechnical Engineer;'Principal Suite 200 Tax: =5 74.27'I4 lYN"W_�1k13�,G't34CICS7CRS.L(YRl ' TABLE OF CONTENTS Page 1.0 INTRODUCTION...........................................................................................................1 ' 1.1 GENERAL.................................................................. I 1.2 PROJECT UNDERSTANDING............................................................................1 1.3 SCOPE OF SERVICES AND AUTHORIZATION....................................................2 ' 2.0 FIELD AND LABORATORY INVESTIGATIONS ...............................................................2 2.1 FIELD INVESTIGATION...................................................................................2 2.2 LABORATORY TESTING.................................................................................3 ' 3.0 GEOLOGIC 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 RECOMMENDATIONS..................................................................4 4.1 GENERAL.......................................................................................................4 4.2 SEISMIC DESIGN RECOMMENDATIONS...........................................................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 PRESSURES.........................................................................10 4.5 BACKFILL PLACEMENT AND COMPACTION....................................................1 1 ' 4.6 EXCAVATION STABILITY 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 EART M70RK........................................................................14 ' 4.9 EROSION CONSIDERATIONS...........................................................................15 5.0 CONDITIONS AND LIMITATIONS .................................................................................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 131-1-1 and 131-1-2 Appendix B: Laboratory Test Results , Figure 13-1 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 34T"STREET/SPRINGBROOK CREEK CULVERT IMPROVEMENT PROJECT CITY OF RENTON,WASHINGTON 1.0 INTRODUCTION 1.1 GENERAL This report presents the results of a geotechnical 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 1 consists of two side-by-side, 30-foot width each,by 8-feet high, three- sided box sections. Option 2 consists of a single, 30-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 need 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 60-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 accordance with 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. Beek 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 INVESTIGATION On April 18, 2005, HWA performed a subsurface exploration program that included drilling two exploratory borings (designated BH-1 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 detennined 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 perfonned using a 2-inch , outside diameter split-spoon sampler and a 140-pound auto-hammer. 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-]. A key to the boring log symbols is also presented in Figure A-L 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 GeoScienees Inc. 1 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 13-1 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. According to the mapping,the peat is typically very soft, and may compress to 10%of original volume when loaded. ' SW 34th St.-Springbrook Ck Report Final(10-14-05).doe 3 HWA GeoSciences Inc. 1 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 alluvium. 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 BH-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 BH-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. l 1 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 El. 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.-Springbrook Ck Reporl Final(10-14-05).doe 4 HWA 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 1 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 Report Final(10-14-05).doc 5 HWA GeoScienecs 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., ldriss, 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.-Springbrook Ck Report Final(10-14-05).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. 1 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 geotechnical investigations for two culverts upstream on ' Springbrook Creek for the City of Kent. The culverts are located at South 192nd Street ' SW 34th St.-Springbrook Ck Reporl Final(10-14-05).doc 7 HWA GeoSciences 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 FOUNDATIONS 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. I£ 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 34th St.-Springbrook Ck Report Final(10-14-05).doc 8 HWA GeoSciences 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 will 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 make a pipe system not cost effective. tRather, we recommend selection of the four-sided box alternative, if reduced defonnation and damage is to be achieved. Alternatively, if a greater risk of potential defonnation damage is considered acceptable a three-sided box founded on spread footings is feasible. ' SW 34th St.-Springhrook Ck Report Final(10-14-05).doc 9 1IWA 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 culvert replacement 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 less 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(10-14-05).doc 10 HWA GeoSciences Inc. , Loadinp,Condition Equivalent Fluid Unit Weiyht (pcf) Active—Static (Kp,) 35 ' Active—Seismic (KAE) 40 At Rest—Static(KO) 55 ' At Rest—Seismic (KoE) 80 ' Passive - Static (Kp) 460 Passive- Seismic (KIE) 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 pcf. ' 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 jbr Road, Bridge, and Municipal 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.-Springbrook Ck Report Final(10-14-03).doc 1 1 HWA 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 trackhoes. 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 1.5H:IV,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 stonn 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 GcoSciences 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 and/or 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(10-14-05).doe 13 HWA GeoSciences 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 EARMWORK 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: , 1) 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.-Springbrook Ck Report Final(10-14-05).doc 14 1I'A'A 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. 1 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. Beck and the City of Renton for design of a portion of this project. This report should be provided in its entirety to prospective contractors for bidding 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 geotechnical 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 geotechnical aspects of construction, particularly construction dewatering, excavation, subgrade preparation,bedding and backfill placement and compaction. ' SW 34th St.-Springbrook Ck Report Final(10-14-05).doc 15 HWA GeoSciences Inc. i 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. ' ,r✓E A. B r- w O)ygy � EXPIRES 08/24/06-7 1 Lorne Balanko, P.E. Brian E. Hall,P.E. , Principal Vice President SW 341h St.-Springhrook Ck Report Final(10-14-05).doc 16 HWA GeoSciences Inc. ' ' .rrl`` i\ ---•�� / �t r �r-i,� , I J (I J L,L.J [lid � 7 . � I 900 �fJL.Jj 1 Lll n_F a �I -1. L _1> j t� r i �� r�,7- j - --- uk�iv��a Boeing.Longacres I. ustrial Perk �_ IJ �I . [y p r �VC_tran�C-il !B V S W-- - - J 2�th� St PROJECT SITE ��__' 7 lo LJI I `y -- t( 1 ri 'S15 -�� — -- i - ;� it 167 Garr tl: :III 1$� 1 IL I' 1'70 Q t -- r 1 NOT TO SCALE VICINITY MAP DRAWN BY KS FIGURE No. TAT SW 34TH STREET CULVERT CHECKED BY LB 1 i11'�,A 1lriGEOSCMNICB M SPRINGBROOK CREEK DATE PROJECT No. RENTON, WASHINGTON 5.17.05 2005-043 ' REV 00 KLS 12/1/64 1 � � J f I ti_ AV; I I C N\\ I 11 , I X z Y= - - J tl 5�Z - - -- --- j1 - -- - .-- - - �_ r� 777 \ Ji �9H 2 -Fjcl� I W u �.. � I \ i 1 0' 10' 20' 40' I l� t,F SCALE: 1"=20' I ` 1 1 1: i - -- - .q,?:_T LEGEND I \ I,I'4' I I 61� 11L1`I fIGUR[»0. H-1 SW 34TH STREET CULVERT BOREHOLE DESIGNATION AND APPROXIMATE LOCATION �n SPRINGBROOK CREEK SITE AND »LCK[V RT LB 2 HMGEOSCIENCES INC EXPLORATION 'ATE ll.,E�T 1, MSE-Al PROVIDED BY:OUANE NARTMAN A ASSOCIATES,INC. RENTON WASHINGTON PLAN 5.17•05 2o05-043 H1IPROJF 170U5 C 5-47-1 HST CULVERT,RENTOMOWG -757TOPO.OYJG REV W KLS 5117M APPENDIX A ' FIELD EXPLORATIONS ' RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE TEST SYMBOLS COHESIONLESS SOILS COHESIVE SOILS %F Percent Fines Approximate Approximate AL Atterberg Limits: PL=Plastic Limit Density N(blowslft) Consistency N(blows/ft) Undrained Shear LL=Liquid Limit ' Relative Density(%) Streng th(psf) CBR California Bearing Ratio Very Loose 0 to 4 0 15 Very Soft 0 to 2 <250 CN Consolidation Loose 4 to 10 15 - 35 Soft 2 to 4 250 - 500 DO Dry Density(pcf) Medium Dense 10 to 30 35 - 65 Medium Stiff 4 to 8 5Do 1000 DS Direct Shear Dense 30 to 50 65 - 85 Stitt 8 to 15 1000 - 2DOO GS Grain Size Distribution ' Very Dense over 50 85 - 100 Very Stiff 15 to 30 2000 - 4000 K Permeability Hard over 30 >4000 MD Moisture/Density Relationship(Proctor) MR Resilient Modulus USCS SOIL CLASSIFICATION SYSTEM PID Photoionization Device Reading ' MAJOR DIVISIONS GROUP DESCRIPTIONS PP Pocket Penetrometer Approx.Compressive Strength(tsf) Gravel and s GW Well-graded GRAVEL SG Specific Gravity , Coarse Clean Gravel TC Triaxial Compression Gravelly Soils it8e or no fin Grained � fin") � GP Poody-graded GRAVEL TV Torvane ' Soils ° Approx.Shear Strength(tsf) More than 50%of Coarse Gravel with ° GM Silty GRAVEL UC Unconfined Compression Fraction Retained Fines(appreciable on No.4Sieve amount of fines) GC Clayey GRAVEL SAMPLE TYPE SYMBOLS ' Sand and Clean Sand •• SW Well-graded SAND ® 2.01'OD Split Spoon(SPT) (140 lb.hammer with 30 in,drop) Sandy Soils Clean or no fines) More than SP Poorly-graded SAND T Shelby Tube 50%Retained 1 50%or More on No. Sand with SM Silty SAND of Coarse a I 3-1/4"OD Split Spoon with Brass Rings ' 200 Sieve Fines(appreciable IJ Fraction Passing Size amount of fines) SC Clayey SAND No.4 Sieve I 1 rO Fine Sift Liquid Limit . Small Bag Sample ML SILT Large Bag(Bulk)Sample ' — lJ Grained and Less than 50% CL Lean CLAY � Core Run Soils Clay OL Organic SILT/Organic CLAY Non-standard Penetration Test (3.0r'OD split spoon) Sift' MH Elastic SILT 50%or More and Liquid LimLimit 01 CH Fat CLAY GROUNDWATER SYMBOLS Passing an No.200 Sieve Clay 50%orMore CZ Groundwater Level(measured at OH Organic SILT/Organic CLAY Size time of drilling) 1 PEAT Groundwater Level(measured in well or Highly Organic Soils PT r open hole after water level stabilized) COMPONENT DEFINITIONS COMPONENT PROPORTIONS COMPONENT SIZE RANGE PROPORTION RANGE DESCRIPTIVE TERMS Boulders Larger than 12In <5% Clean ' Cobbles 3 in to 12 in Gravel 3 in to No 4(4.5mm) 5•12% Slightly(Clayey,Silty,Sandy) Coarse gravel 3 In to 3/4 in Fine gravel 3/4 in to No 4(4.5mm) 12.30% Clayey,Silty,Sandy,Gravelly ' Sand No.4(4.5 mm)to No.200(0.074 mm) Coarse sand No.4(4.5 mm)to No.10(2.0 mm) Medium sand No.10(2.0 mm)to No.40(0.42 mm) 30-50% Very(Clayey,Silty,Sandy,Gravelly) Fine sand No.40(0.42 mm)to No.200(0.074 mm) Sift and Clay I Smaller than No.200(0.074mm) Components are arranged in order of increasing quantities. NOTES'. Soil classifications presented on exploration logs are based on visual and laboratory observation. Soil descriptions are presented in the following general order. MOISTURE CONTENT Density/consistency,color,modifier(ifany)GROUP NAME,additions to group name(ifany),moisture DRY Absence of moisture,dusty, content. Proportion,gradation,and angularity of constituents,additional comments. dry to the touch. (GEOLOGIC INTERPRETATION) MOIST Damp but no visible water. WET Visible free water,usually Please refer to the discussion in the report text as well as the exploration logs for a more soil is below water table. complete description of subsurface conditions. ' SW 34TH STREET CULVERT LEGEND OF TERMS AND 1 SPRINGBROOK CREEK SYMBOLS USED ON HWAGEOSCIENCES INC RENTON, WASHINGTON EXPLORATION LOGS PROJECT NO.: 2005-043 FIGURE: A-1 LEGEND 2005043.GPJ 5119/05 DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 18.00 t feet DATE STARTED: 4/18/2005 DRILLING METHOD: HSA;Mobile B-51 DATE COMPLETED: 4/18/2005 , SAMPLING METHOD: SPT w/Autohammer LOGGED BY: B.Thurber LOCATION: See She d Exploration Plan,Figure 2 V) m 0: Standard Penetration Test ' d Fa < (140 lb.weight,30"drop) J y� � � ♦ Blows per toot p O ' � � � tr 2 O tm u}i DESCRIPTION (0 y aUJ 0 10 20 30 40 50 O 0 o t GP rox.3 inches A.C. ' o Q Medium dense,brown,slightly silty,medium to coarse sandy,fine to coarse GRAVEL,moist. Gravel mostly<2 Q inches. ' o Q (PITRUN FILL) • S-1 10-12-8 5 = OL 4 • 5 Soft,dark brown,organic SILT,moist. S-2 2-2-2 + � � — ----------- S3 1-1-2 ..-:.. .�.. ' Soft,dark brown and light gray,fibrous organic SILT,moist.— ; ML Soft,gray plastic SILT`oist. OL Soft,dark brown and light brown,organic SILT,moist. .... """'"""'•' 10 SP Loose,gray,slightly silty,fine SAND,wet. Scattered fibrous Q �;,,,•; ..�.... .... .... 10 -4 ' SM organics. �/ S 1-1-2 (ALLUVIUM) —————————————————————— .;. SP ' Loose grading to very loose,black,clean,fine to medium S-5 3-3-2 GS ......•........................... SAND,wet. Mostly black grains,some red. = t 1.5 inch Lens of purple-brown SILT at 13 feet,with a few ' fibrous organics. :....:....:....:....:....:....:....:... , 15 .......... ...................:....:....:.... 15 ------ s-sa 0-1-1 . ———————————————— .... .... .... �.. .... .... .... SM Very loose,dark gray,silty one SAND,wet. �S-61:i SP —————————————————————— A. SM Loose,black,clean,fine to medium SAND with beds or dark S-7 2-2-5 GS ................................................. gray,silty fine SAND,wet. Finely bedded. t t t 20 SM Loose ray-brown,fine sandy SILT and silty fine SAND—— S 8 3-2-2 4.. 20 ' g t with two beds of black,clean,fine to medium SAND,wet. ML Loose,gray-brown,SILT,wet. Non-plastic. SP ---------------------- 25 25 0 20 40 60 80 100 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 necessarily be indicative of other times and/or locations. ,SW 34TH STREET CULVERT BORING: BH-1 91 SPRINGBROOK CREEK HWAGEOSCIENCES INC. RENTON, WASHINGTON PAGE: 1 of 3 ' PROJECT NO.: 2005-043 FIGURE: A-2 BORING 2005043.GPJ 5/19/05 DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 18.00 t feet DATE STARTED: 4/18/2005 DRILLING METHOD: HSA;Mobile B-51 DATE COMPLETED: 4/1812ODS SAMPLING METHOD: SPT w/Autohammer LOGGED BY: B.Thurber LOCATION: See Site 3 Exploration Plan,Figure 2 ' W mrX Standard Penetration Test j < (140 lb.weight,30"drop) J J O W � w— Q ♦ Blows per foot O ro Z IL c� 2 z 0 IX O.`m. W 7 DESCRIPTION h to d A O O 0 10 20 30 40 50 25 25 Medium dense,black,clean,fine to medium SAND,wet. �S-9 5-11-11 Massive. Sp —————————————————————-- SM 30 ...... ...�:. ..:. .... .... .... 30 Medium dense,black,clean to silty,fine SAND,wet. �5-10 3-" GS Partly decomposed trunk wood at 31 feet;1/2-inch lens. ML 35 ............... '....:....:....'� 35 Very loose,dark olive-gray,non-plastic SILT(to 35.5 feet) 1�7 11a 0 -0 ....... over very soft plastic SILT,wet. Scattered shell fragments -11b and woody fragments. One bivalve shell 1 inch long. (ESTUARINE DEPOSITS) —————————————————————— ....:....:.........:................... ML SM 5-12 CN . ............................... Very loose,dark olive-gray,plastic and non-plastic SILT, wet. Grades to fine sandy SILT. 13a aa0 ---------------------- SM Very loose,gray,silty,fine to medium SAND with beds of 13b sandy SILT,wet. Scattered shell fragments,nearly whole to detrital(<1/8 inch). Scattered woody fragments. i r SP —————————————————————— SM Loose,gray,slightly silty,fine to medium SAND,wet. Finely 45 .........�.............i....i.... bedded. Scattered shell fragments. — 14a 3-2-2 i ML Soft,olive-brown,slightly sandy SILT,moist to wet. Flnely -1Alb ' SM bedded. Partly decomposed woody fragments in two lenses,<1/4 inch,at 45.75 and 46.5 feet. SM —————————————————————— 50 0 20 40 60 80 100 ' Water Content(%) Plastic Limit 0 --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 necessarily be indicative of other limes and/or locations. BORING: SW 34TH STREET CULVERT Y�ii 1 I SPRINGBROOK CREEK BH-1 ' HWAGEOSCIENCES INC. RENTON, WASHINGTON PAGE: 2 of 3 PROJECT NO.: 2005-043 FIGURE: A-2 BORING 2005G43.GPJ 5119/05 1 DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 18.00 t feet DATE STARTED: 4/18/2005 ' DRILLING METHOD: HSA;Mobile B-51 DATE COMPLETED: 4/18/2005 SAMPLING METHOD: SPT w/Autohammer LOGGED BY: B.Thurber LOCATION: See Site S Exploration Plan,Figure 2 w _ Standard Penetration Test , q m w c� a �1 Q (140 lb.weight,30"drop) J Z JO z ♦Blows per foot UJI m 8 m 2 z1 ❑gym. u}i 7 DESCRIPTION rn n a O O 0 10 20 30 40 50 50 50 , Loose,gray,slightly silty to silty(stratified),fine SAND,wet. �S-15 3-2-3 : Scattered lenses of partly decomposed woody debris. 2-inch lens of clean,fine to medium SAND at 50.25 feet. ---------------------- r 55 ... ....:� i ....�.. .... 55 Very soft,gray,plastic SILT,wet. Scattered shell �5-16 0-0-0 AL fragments. 1......•..1....t....t.... ....;.. . Fine sand lenses(1/4 inch)at 55.5 and 56.5 feet. :.... ....:....:.... ...:.... .... .... 60 1 Very soft,gray,SILT,moist to wet. Scattered shell �S-17 0-0-0 fragments,woody organics. Massive. ....:....:.. .: Borehole terminated at 61.5 feel. Ground water encountered at approx.10 feet during drilling. ................................................. Auger filled with drilling mud below 10 feet to prevent heave. 65 65 r 70 :....:....:... 70 ......... L 75 75 0 20 40 60 80 1130 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 necessarily be indicative of other times and/or locations. ' BORING: SW 34TH STREET CULVERT USPRINGBROOK CREEK BH-1 LM I HWAGEOSCIENCES INC. RENTON, WASHINGTON PAGE: 3 of 3 ' PROJECT NO.: 20055-043 FIGURE: A-2 BORING 2005043.GPJ 5119/05 i DRILLING COMPANY; Holocene Drilling SURFACE ELEVATION: 18.50 t feet DATE STARTED: 4118/2005 DRILLING METHOD: HSA;Mobile B-51 DATE COMPLETED: 4/18/2005 SAMPLING METHOD: SPT w/Autohammer LOGGED BY: B.Thurber LOCATION: See Site&Exploration Plan,Figure 2 w Standard Penetration Test iY � Q N to � yay � t I'_ Q (140 lb.weight,30"drop) J F Z O h �? W ♦ Blows per foot u� w ro Z ua m (J z O °WW m O ti Li M 23 DESCRIPTION V) h d O O 0 10 20 30 40 50 O 1 0 0 SM Sod Loose,rust-mottled brown,silty,fine to medium SAND, moist. Scattered fine gravel. •i i (FILL) S-1 2-2-2 • SM Loose,purple-brown,very silty,fine SAND,moist. OL Soft,dark brown, ic SILT,moist. Scattered fibrous 5 r� 5 organ _ organics. S-2a 0.2-2 ML Soft,gray,non-plastic SILT,wet. Scattered rootlets. S-2b Wood fra ments in lower3 inches. ""...... OL o y-9------------------ Id Soft,dark brown,organic SILT,wet. Abundant wood S-3a 0-0-1 fragments,leaves(detrital). Lens of gray sift at 7.75 to 8 feet. i —————————————————————— ....;....;....;....;....;....;....;.... ML Soft,brown-gray,SILT,wet. Abundant fibrous organics. S-3b 10 —————————————————————— . .... .... .... .�. .... .... .... 10 SP Very loose,gray,clean,fine SAND,wet. With beds of S-4 0-0-2 ; SM brown-gray SILT,dark brown organics,and fine to medium = .... SAND. .........:.... ....,....1....,.... ....;.... SM Loose to medium dense,dark gray,slightly silty to silty,fine to medium SAND,wet. Stratified,with lenses of non-plastic 5-5 44 6 SILT. ——————————————————————15— SP Medium dense,black,clean,fine to medium SAND,wet. ; ; ; 15 Mostly black grains,some red. S-6 3-5-6 GS ; ............. ML Very soft,gray,SILT,wet. Scattered shell and woody A � fragments. S-7 aaz 1/2 inch lens of yellow,non-plastic SILT at 18.5 feet (Volcanic ash?). —— 20 ------------------- — —20 SP Very loose,interbedded dark gray,slightly silty,fine SAND S 8 0-0-1 GS SM and black,clean,fine to medium SAND,wet. With lenses i of purple-brown SILT and silty fine SAND. Scattered woody ; organics. ML —————————————————————— SM 25 25 0 20 40 60 80 100 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 necessarily be indicative of other times and/or locations. T BORING: SW 34TH STREET CULVERT BH-2 UL ,' SPRINGBROOK CREEK HWAGEOSCIENCES INC RENTON, WASHINGTON PAGE: 1 of 3 PROJECT NO.: 2005-043 FIGURE: A-3 BORING 2005043.GPJ 5/19/05 DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 18.50 t feet DATE STARTED: 4119/2005 DRILLING METHOD: HSA;Mobile B-51 DATE COMPLETED: 4/18/2005 SAMPLING METHOD: SPT w/Autohammer LOGGED BY: B.Thurber LOCATION: See Site&Exploration Plan,Figure 2 rn d W ! W .. Standard Penetration Test U] to Q O W (140 lb.weight,30'drop) to ' J Z to ♦Blows per toot rn a.a. J W Z O."m.. CO- DESCRIPTION to N a O O 0 10 20 30 40 50 ❑`� 25 25 Soft,gray-brown,SILT,fine sandy SILT,and dark gray,silty �S-9 2-4-12 fine SAND,wet. 7-inch long branch in lower 9 inches(blow counts overstated?) (ESTUARINE DEPOSITS) C 30 ... ... 30 ! Loose,dark gray to dark purple-gray,fine sandy SILT,wet. �S-10 2-3-2 GS Non-plastic. Scattered shell fragments in two lenses. Very loose,dark gray,slightly fine sandy,non-plastic SILT, �S-11 040-0 moist to wet. Finely bedded. Scattered shell fragments. 40 ......... ..4....:....:....:.... 40 Very loose,gray interbedded SILT,sandy SILT,and silty �S-13 0.0-0 fine to medium SAND,wet. Abundant shell fragments. —————————————————————— SM ....c�.. .... .... ....c.... 45 Very loose,gray,very silty,fine to medium SAND grading to �S-14 0-0-0 clean,fine to medium SAND,wet. Abundant shell and wood fragments. ' —————————————————————— .... ML ................... SM :....:....:....:....: 50 [T� L50 0 20 40 60 80 100 Water Content Plastic Limit i 19 Liquid Limit Natural Water Content NOTE: This log of subsurface conditions applies only at the specified location and on the dale indicated and therefore may not necessarily be indicative of other times and/or locations. LM, SW 34TH STREET CULVERT BORING: SPRINGBROOK CREEK BH-2 HWAGEOSCIENCES INC RENTON, WASHINGTON PAGE: 2 of 3 ' PROJECT NO.: 2005-043 FIGURE: A-3 BORING 2005043.GPJ 5119/05 DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 18.50 t feet DATE STARTED: 4/18/2005 DRILLING METHOD: HSA;Mobile B-51 DATE COMPLETED: 4/18/2005 SAMPLING METHOD: SPT w/Autohammer LOGGED BY: B.Thurber LOCATION: See Site&Exploration Plan,Figure 2 to of rn m of Standard Penetration Test U ( y Qz (140 lb.weight,30"drop) 0 v) b ♦ Blows per foot wa m CJ 2 2 Z O O 0- ❑.gym vYi DESCRIPTION U) W a O O 0 10 20 30 40 50 O�' ' 50 Very loose,gray,non-plastic SILT and fine sandy SILT,and �S-15 0-0-0 50 very soft,plastic SILT,wet. Scattered shell fragments. ML ---------------------- . 55 ....:....4..--I ....�...: ss Very soft,brown-gray,plastic SILT,moist to wet. Finely �5-16 0 0 0 . bedded. Scattered shell fragments. Sample deformed laterally when sampler opened;very sticky SIN. 60 .... .... .... .... ....�.. .... .... ' 60 Very soft,brown-gray,plastic and non-plastic SILT,moist. S-17 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 feet to prevent heave .................................. (therefore ground water level obscured). 65 70 :....:.. .:.. . .. . .. . .. . .... .... 70 75 75 0 20 40 60 80 100 ' 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 necessarily be indicative of other times and/or locations. BORING: SW 34TH STREET CULVERT BH-2 90,1 SPRINGBROOK CREEK HWAGEOSCIENCES INC RENTON, WASHINGTON PAGE: 3 of 3 PROJECT NO.: 2005-043 FIGURE: A-3 BORING 2005043.GPJ 111111.5 ' APPENDIX B ' LABORATORY TEST RESULTS 1 1 1 1 1 1 1 1 rr rr rl rr rr ar �r rr rr rr r rl� �r r■ rr rr rr rr rr GRAVEL SAND SILT CLAY Coarse Fine Coarse Medium Fine :] U.S. STANDARD SIEVE SIZES 3/4" 3" 1-1/2" 518" 3/8" #4 #10 #20 #40 #60 #100 #200 100 I I I I 1 I I I !I 90 I I I I I I I I I I ao Z I 1 1 I I I I I it 0 70 I I I 1 I I I I I I I I I I I I I I I II } 60 m W 50 I I I I 1 I I I I I Z I I I I I I I i I I W I I I I I I I I I 1— 40 Z I I I I I I I I I I W I 1 1 I I I I I I 1 U W 20 I I I I I I I I I I I I I I I I I I 10 I I I I 1 I I I I I I I I 1 I 1 I I 1 0 50 10 5. 1 0.5 0.1 0.05 0.01 0.005 0.001 0.0005 GRAIN SIZE IN MILLIMETERS SYMBOL SAMPLE DEPTH(11) CLASSIFICATION OF SOIL-ASTM D2487 Group Symbol and Name %MC LL PL PI Gravel Sand Fiones BH-1 S-5 12.5-14.0 (SP-SM)Black,Poorly graded SAND with silt 27 0.0 90.7 9.3 ■ BH-1 S-7 17.5-19.0 (SM)Dark brown,Silty SAND 31 0.0 58.4 41.6 BH-1 S-10 30.0-31.5 (SM)Black,Silty SAND 32 0.1 1 85.4 14.5 SW 34TH STREET CULVERT PARTICLE-SIZE ANALYSIS IRTA OF SOILS SPRINGBROOK CREEK METHOD ASTM D422 MAGECISCIENCES INC. RENTON, WASHINGTON PROJECT NO.: 2005-043 FIGURE: B-1 HWAGRSZ 2005043.GPJ 5/19105 GRAVEL SAND I SILT CLAY Coarse Fine Coarse Medium Fine U.S. STANDARD SIEVE SIZES 3/4" I 5/8" 3/T #4 #10 #20 #40 #60 #100 #200 100 90 i l i I I I I I I I I I 80 = I I I I I l I I I I 0 70 pip 60 W 50 I I I I I I I I I I F- 40 I I I I I I I I I I Z I I I I I I I I W I I I I I I I I I I 30 W I I I I I I I I I I Ti 20 I I I I I 1 I I I I 10 t) 50 10 5 1 0.5 0.1 0.05 0.01 0.005 0.001 0.0005 GRAIN SIZE IN MILLIMETERS SYMBOL SAMPLE DEPTH(ft) CLASSIFICATION OF SOIL-ASTM 02487 Group Symbol and Name %MC LL PL I pi I Gravel Sand Fiones • BH-2 S-6 15.0-16.5 (SM)Dark gray brown,Silty SAND 30 0.0 81.4 18.6 ■ BH-2 S-8 20.0-21.5 (SM)Dark brown,Silty SAND 29 1.2 62.5 36.3 A BH-2 S-10 30.0-31.5 (ML)Dark grayish brown,SILT 36 0.0 10.2 89.8 SW 34TH STREET CULVERT PARTICLE-SIZE ANALYSIS OF SOILS SPRINGBROOK CREEK METHOD ASTM D422 HWAGEOSCIENCES INC RENTON, WASHINGTON PROJECT NO.: 2005-043 FIGURE: B-2 HWAGRSZ 2005043_GPJ 5/19/05 I- 60 CL CH 50 'lox a X 40 Lu Z } 30 U H Q 20 J 10 CL-ML ML MH 0 0 20 40 60 80 100 LIQUID LIMIT (LL) SYMBOL SAMPLE DEPTH(ft) CLASSIFICATION %MC LL PL PI %Fines • BH-1 S-16 55.0-56.5 (CL)Dark gray,CLAY 52 38 21 17 SW 34TH STREET CULVERT LIQUID LIMIT, PLASTIC LIMIT AND SPRINGBROOK CREEK PLASTICITY INDEX OF SOILS HWAGEOSCIENCES INC. RENTON, WASHINGTON METHOD ASTM D4318 PROJECT NO.: 2005-043 FIGURE: B-3 HWAATTS 2005043.GPJ 5119105 SAMPLE DEPTH(ft) CLASSIFICATION ' BH-1 S-12 37.5-39.5 (CL)Gray,CLAY 1.10 1.05 1.00 (D 0.95 O o , O> 0.90 0.85 0.80 , 0.75 0.1 1 10 100 STRESS (ksfI ' INITIAL FINAL LIQUID LIMIT,LL(%) ' WATER CONTENT(%) 44.7 30.0 PLASTIC LIMIT,PL(%) DRY DENSITY(PcO 76.1 92.0 PLASTICITY INDEX,PI(%) DEGREE OF SATURATION(%) 99.9 100 ASSUMED SPECIFIC GRAVITY 2.68 ' ONE DIMENSIONAL CONSOLIDATION , S.W. 34th Street Culvert PROPERTIES OF SOIL METHOD ASTM D2435 ' HWAGEOSCIENCES INC PROJECT NO.: 2005-043-��OO FIGURE: B-4 HWACONV 2005043-11DO.GPJ 5119105 Station num, -S% (obser) Table of daily values for the 12-month period ending September 1997 Observed Flow (cfs) SPRINGBROOK CK. AT SW 27th ST (observed) Day October November December January 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 2.9 5.2 136.3 19.5 8 2.8 3.1 190.4 43.8 9 2.8 3.0 130.1 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 10.8 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 76.4 227.9 24.4 30 8.9 56.3 478.2 179.3 31 5.2 500.8 91.5 Mean 21.6 48.1 106.6 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. :S9b (obser) Table of daily values for the 12-month period ending September 1996 Observed Flow (cfs) SPRINGBROOK CK. AT SW 27th ST (observed) Da October November December January February March April May June July August September 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 2 108.0 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 10.1 39.3 16.1 4.8 5.5 2.9 4.6 11.8 10.3 5 56.7 2.8 - 13.4 98.8 9.2 4.2 4.9 2.9 3.0 5.5 5.5 6 49.2 3.0 - 45.7 182.5 7.3 31.9 4.5 2.9 2.9 4.7 7.2 7 46.1 14S.3 - 24S.7 163.7 6.8 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 IS 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 28.8 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 - 97.8 - 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 2.8 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 2.8 31 2.7 24.9 9.8 22.9 3.1 4.3 5.3 Mean 41.5 62.5 57.5 75.3 121.3 11.5 46.9 14.6 3.3 5.2 8.7 8.6 38.1 Minimum 2.7 2.6 3.6 9.8 8.2 3.6 4.0 3.1 2.8 2.8 3.3 2.8 2.6 Maximum 201.1 322.4 187.9 266.2 677.1 63.3 378.4 154.7 12.4 32.7 104.3 43.4 677.1 Station num. :S9b (obser) Table of daily values for the 12-month period ending September 1995 Observed Flow (efs) SPRINGBROOK CK. AT SW 27th ST (observed) Day October November December January February March April May June July August September 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 30.7 106.9 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 28.8 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 58.5 10.1 9.3 10 7.5 17.2 8.7 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 8.1 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 2.8 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 2.8 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 numk,. -S9b (obser) Table of daily values for the 12-month period ending September IM Observed Flow (cfs) SPRINGBROOK CK. AT SW 27th ST (observed) Day October November December January February March April May June July August September Annual 1 2.5 2.8 - 60.8 3.1 44.8 3.4 5.7 1S.0 31.1 6.0 4.7 2 2.5 2.8 9.8 38.2 3.0 92.2 3.2 S.6 8.0 28.S 5.7 4.7 3 2.5 5.6 6.9 26.0 3.0 151.4 19.5 S.4 8.1 9.6 5.7 18.2 4 IS 3.0 24.S 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 8.4 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 10.8 9.4 10 2.5 3.1 89.9 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 8.6 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 15 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 98.5 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 3.8 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 6.8 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 6.8 9.6 7.4 4.3 4.7 26 2.9 4.7 2.8 6.0 50.0 5.4 3.8 6.8 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 28.3 4.5 4.5 7.4 9.1 6.6 4.7 5.3 29 2.8 44.1 2.8 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 7.8 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 98.5 47.8 10.8 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 17.1 98.5 10.5 47.8 5.1 10.8 6 18.2 9.7 98.5 1995 5.7 19.5 8.7 63.1 21.7 198.3 23.1 137.5 14.8 198.3 1994 3.3 12.4 5.2 32.7 8.7 104.3 8.6 43.4 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 10.3 65.6 Springbrook Creek at SW 27tb Street Rating Curve (8 July 1997) N m 00 16.00 r d WC Di Measurements N t 5.00 14.00 - P ' _-_}�__-..... .--..._ ---•------••-. __•-----_____• __..._._..____�_ i 0 N 12.00 UN rn y ; ! 7 ~ ----1-- ----- --- ' Uses double entry sting cur4e above ley. 9.9t1; NGVO #�10.00 ----------------,---- - a ----- -- -- 9.00 �-- ------- -- -- -- ----- -------- �, /o 8.00 w 7.00 - --------------1--------- - ------------ ----- -•-•-•-------- - ' ' •----•-- -----•-•------•_. -3 4.0O 600.0 aw.0 1000.0 y 0.0 200.0 400.0 �r] Flow (Cfs) Ncz-rt�w�sr f-� YD�a ��-�� rDA/SvcTriNTs lk S7ec`,t�1 C7.4�i� j 1 1 FOUND 2" BRASS CAP IN CONCRETE, DOWN 0.4' IN 1 CASE AT THE CENTER OF INTERSECTION WITH SW 34TH STREET AND OAKSDALE AVE SW. SURVEY CONTROL DATA BASE POINT ID#619� PUBLISHED i ELEVATION 19.504 U.S. SURVEY FE X . VJ z I I n 0o m L� • � BM#2 ^ €I LL # I 00 SSMH < RIM 19.22 IE E 13.54 IE W 13.48 I CHANNELED i J II ff � 0 I II 1� � N z SET PK NAIL € f AT FRONT OF WALK AT N.W. I ? CORNER CONCRETE DRIVEWAY NOTES Lij N 166,982.0625 ,... .... _ f ! ! _ .. 12 ._ : 1 E 1,295,355.6802 WALK (' t ....." , ;I z ECC <` ELEVATION 18.82 FEET i ........ . .. # Il HORIZONTAL DATUM: 10 o , I CB TYPE I ; •., Wes\ AMERICAN DATUM 83/91. HELD NORTH 01'35'48" EAST BETWEEN MONUMENTS AT THE INTERSECTION OF LIND AVENUE w 4 :: s >� • RIM 19.50 NORTH o ( m ` IE W 17.66 , ( WALK SW AND SW 30TH ST(NOT OPEN) AND LIND AVENUE SW AND SW 23RD ST(NOT OPEN). m _ WL 17.66ry j cs ASPHALT BOT 15.82 �..--... ......_ ....... Ecc"" VERTICAL DATUM:CONCRETE ASPHALT NORTH AMERiu'AN VERTICAL DATUM 88. HELD CITY OF RENTON MONUMENT NO. 1861 AT THE INTERSECTIONS OF LIND AVENUE ' 1 I o II `i' SW AND SW 30TH ST(NOT OPEN) ELEVATION 20.00 FEET AND MONUMENT NO. 1551 AT LIND AVENUE SW AND SW 23RD ST(NOT C SE EL 18.67 m D OPEN) ELEVATION 21.32 FEET. BOLT EL 15.89 ... .� � / I Ecc..t -- DHA BM#1: TOP NORTHWEST BASE BOLT OF LIGHT STANDARD ±126 FEET EAST OF THE CENTERLINE OF SPRINGBROOK CREEK BH-2 <� I I ON NORTH SIDE OF 34TH STREET SOUTHWEST. ELEVATION 18.92 FEET CONCRETE �� .. 50 WETLAND BUFFER ' DHA BM 2: CHISELED SQUARE AT SOUTHEAST CORNER CONCRETE TRANSFORMER, f 175 FEET WEST OF SPRINGBROOK CREEK s ; 50 WETLAND BUFFER CENTERLINE AND 12.0 FEET NORTH OF BACK OF WALK ON NORTH SIDE SOUTHWEST 34TH STREET. ELEVATION 21.10 FEET .._........^.._----...............-..-......_....ECC •� EC r r "'""•'"^"'2(}- ....... .... TOPOGRAPHIC MAPPING NOTES: rn THE MAP SHOWN HEREON IS THE RESULT COMPLETED ON OF A TOPOGRAPHIC SURVEY B DUANE HARTMAN & ASSOCIATES, INC. (DHA) U Y m F 21 2005 ALL EXISTING UTILITIES SHOWN HEREIN W FIELD I - 'S I`o :%. SDMH PAINT OUT DURING THE COURSE OF THE FIELD SURVEY DUANE HARTMAN & ASSOCIATES, INC (DHA) ASSUMES NO LIABILITY rri� iz l RIM 19.45 "...:� ^ .. BORE HOLE "` -i - - --'- FOR THE ACCURACY OF THE UTILITY PAINT-OUT. DHA ASSUMES NO LIABILITY, BEYOND SAID DATE, FOR ANY FUTURE SURFACE WETLAND 1 -� 1 ;; z i IE W 11.89 8..".� - " .. .. m ( li I IE NE 11.83 FEATURE MODIFICATIONS OR CONSTRUCTION ACTIVITIES THAT MAY OCCUR WITHIN OR ADJOINING THE PERIMETER OF THIS SURVEY. _...... - _" m CONTACT DHA ( 2 /483 535 ) FOR SITE UPDATES AND VERIFICATIONS. WL 12 30 4 .._..... __.....-18_.. ..."..w WATER SURFACE z I z l � I m � z CD z1:1 BOT 11.25 '`•' m _ '` f o WETLAND...... .............. 11.00 FEET it f D 2 ON 04/19/2005 f cn 2iil'I 4 � n �^ - f -12.08 fi ..._ _ rn cl _... 06` ...-...._.. _....._...... . t : ROAD CENTERLINE O MONUMENT IN CASE 74 ..r...-- -.. ....._.f SP-3 -w... ROAD RIGHT-OF-WAY PROJECT BENCHMARK 20 _ 72 CMP STORM CULVERT - 7.58 10 - gp_g �-� BUILDING x PK NAIL (CONTROL) m 72"CMP STORM CULVERT IE . .09 m f z _ - ( I E=7.91 - _...._........ i WATER SURFACE 11.03 FEET SPRINGBROOK CREEK m ._ z -m ' FENCE LINE o REBAR AND CAP ON 04/19/2005 It 8.12 �� f „ s SPRINGBROOK CREEK WATER SURFACE 10.97 FEET o I AT 2:20 F.M. ON 04/19/2005 ...... ....... ....................... ............................. 72 CMP STORM CULVERT ` m� IE=8.20 -_y CONTOUR INTERVAL (2 FEET) CULVERT j IV N � �i 1 _ 1 .... ... ." 19 - -"' 72"CMP STORM CULVERT - CONTOUR INDEX (10 FEET) ❑ STORM DRAIN CATCH BASIN . _••. 8 _ _ 1 , i t n _..,__..._......_. ,,.-.,. 8'PVC STORM DRAIN P , ; •. STORMDRAIN CLEANOUT - i BLDG BUILDING STORM DRAIN MANHOLE f . w LOL --_ i BORE CB TYPE I CLF CHAIN LINK FENCE ® �s J RIM 17 34 `� -- CONIFER TREE . SP-1 I IE 13.6 �' �c,��� CB TYPE 1 SP-6 ; N 6 ---•....-..-......~ -..•--.-.^-•••. 1 `^... ` '%" WL 13.54 RIM 17.47 ..•-•.......••---.• CONC CONCRETE {" I o - $: F I w DECIDUOUS TREE ..-. ._. _. BOT 11.54 BH-2 IE S 13.41 - ......W .... _ .......... _ ..........__ .-.........__..............�..._._..---_---- _. � 1 IE N 13.23 I I - _ __ -.............._� _ .._,� CMP CORRUGATED METAL PIPE In w ASPHALT TRAIL ® 2.21 =:'.....................' ___ ...� _ _... SIGN ( I FOUND REBAR AND CAP 0.5' SQUARE BOLLARDS I{ SDMH BOT113.23 .....� - - -•••• •^_... _.._... :::: •--...... - s.� _. _._...__ � � "BCE 27328" 1� RIM 18.16 ASPHALT TRAIL ECC EXTRUDED CONCRETE CURB ® POTHOLE lh� F- !ui WL 10.76 x-SET PK NAIL ORN ORNAMENTAL 0 SANITARY SEWER MANHOLE --- . SET PK NAIL o BOT 8.74 . _� --.....N 167,138.7943 20 0 20 40 _._...." ....._ _. .......... - = =-•• M-.:. �U. ,� CASE EL 18.60 i : AT N.E. END ASPHALT FOOT y { m n _ -. " ........... _ ...._ 2�1 E 1,295,545.5859 U I; ECC , BOLT EL 16.84 { PATH NEAR BACK OF WALK ! -- """" ""- - - - -••-••• _ ... _ .. _...... W .T.."" 1 "=20'-O" OHW ORDINARY HIGH WATER UTILITY POLE WITH LIGHT o :. .... .......... _ _ _ :m. :W::`:: ELEVATION --- � N 166,966.6052 1 FEET 20 ¢- -/ t ! E 1,295,541.8269 _o SSMH ECC Scale Feet (( PVC POLYVINYL CHLORIDE PIPE P LIGHT POLE _ 1 ( �! I # s ASP RIM 21.04 ELEVATION 18.57 FEET "' �_ g" IE E 14.99 WATER HYDRANT o , n " r 8"PVC IE 891, SP SOIL PLOT CD CD 50 WETLAND BUFFER ; _u . � ICV• tVMH I CHANNELED! \ MH STORM DRAIN MANHOLE _. -: :. ::... I m ECC.... i _._......_..�.._ ........�......__-.........w..--.....__. # „ -. _ � �' SD D4 WATER VALVE ..., 1i . IECC SSMH 1 .......... .. _.. N ��; SSMH SANITARY SEWER MANHOLE WHEELCHAIR RAMP o CONCRETE SCALE RIM 19.93 t o %" IE SE 15.51 �' _ i IE N 15.47 z $' t ASPHALT i � �- •:•• -' 0 NWETLAND BUFFER_.. S , -..�.-_.w ....�..--_......� 1 I , - � UFF P WETLAND FLAG CHANNELED r j SSMH r `--• p BLDG \`:f m m 1 ( RIM 18.14 __• .^.•_...:_ �. • ASPHALT - • c ^ IE N 14.64 UTILITY f OTHOLE RESUL TSB _, , _..... __.. �.. i p f i' IE W 14.62 : CB TYPE I ; + o` RIM 2085. �. DATE 05/12/2005 U o E 14.591 l: I ���. z CONCRETE SCALE SET PK NAIL CHANNELEDI IE E 18.33 r 6C 18.35 � I N 166,960.3218 �I= rmrn t z T •05 -' "-----• .......-- E 1,295,610.6890 _ �� m �� 1 17 I 2-STORY POTHOLE ID I TARGET DEPTH TO TOP OF DEPTH TO BOT OF PIPE I CONDUIT PIPE MATERIAL HUB E SUBSURFACE w _ ..... ......._,_. ' o I: T;. j UTILITY UTILITY IN INCHES UTILITY IN INCHES SIZE N INCHES ELEVATION COMPOSITION ELEVATION 18.90 FEET z t CONCRETE a ECC no m BM#1 ::.. :: ::.: W... .. == :..: z o C-) � I ,�, w ��,, .� � j � TILT UP P1 POWER 42 69" 2 8" 2 4" PVC 17.70' ROCKY BUILDING � P2 POWER 41 49 (2)8" (2)4 PVC 18.12 ROCKY � ; N I t P3 POWER 44" 71 (2)8" (2)4' PVC 18.16 ROCKY ICU , I T1 TEL 37 64" 27" WIDE CDF DUCT 18.44' ROCKY i I T2 j TEL 25" 51" 25" WIDE CDF DUCT 18.47' ROCKY U T3 ; TEL 30" 54" 25" WIDE CDF DUCT 18.21' ROCKY 3.3 U d G 1 GAS 39 43 4 PE 18.31 ROCKY E G2 I GAS 35 39 4 PE 18.29 ROCKY / o� _ G3 GAS 31.5 35.5 4 PE 18.23 ROCKY o NO2*05'50"E LIND AVENUE SW N01'35'48"E 2594.76' FOUND LEAD IN TACK 1017.10' W1 H2O 35 51 16 DI 18.26 ROCKY I IN CONCRETE DOWN FOUND TACK IN LEAD IN CONCRETE 0.8' IN CASE MONUMENT, DOWN 0.7' IN CASE FOUND TACK IN LEAD IN CONCRETE DOWN o CITY OF RENTON MONUMENT NO. 1861 0.6' IN CASE, CITY OF RENTON MONUMENT oN ELEVATION 20.00 FEET NC. 1551. ELEVATION 21.32 FEET NE 1/4, SE 1/4, S 25, TWP 23 N, R 4 E & NW 1/4, SW 1/4, S 30, TWP 23 N, R 5 E, W.M. Cl DATE: N SURVEYED: SCALE: VERTICAL NAVD 1988 Q > ao Z DESIGNED: 1 n-20I HORIZONTAL: NAD 1983/1991 :� ,� CITY 0 F SW 34TH STREET FIELDOBOOK: -05 w DRAWN: R E N TO N CULVERT IMPROVEMENT PROJECT PAGE: L.L. Q O` ONE INCH FIGURE 2 DRAWING N0: DATUM w 3 CHECKED: AT FULL SCALE Planning/Building/Public Works Dept. EXISTING SURVEY 05-757 IF NOT ONE INCH U SCALE ACCORDINGLY SHEET: OF: o NO, REVISION B ! DATE APPR AP MAP W Ai - N N N N A A