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HomeMy WebLinkAboutDesign Report - Final - stamped CITY OF RENTON HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECT FINAL DESIGN REPORT (Partially funded through a Washington State Department of Ecology Water Quality Grant) JUNE 10, 2020 This page left intentionally blank. HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECT FINAL DESIGN REPORT CITYOF RENTON JUNE 10, 2020 WSP WSP.COM WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 4 City of Renton This page left intentionally blank. WSP Final Design Report August 10,2020 Heather Downs Detention Pond Water Quality Retrofit Project Final Report Supplement City of Renton Heather Downs Detention Pond Water Quality Retrofit Project Supplement to June 10, 2020 Final Design Report Auguest 15, 2020 Following WSP’s final design report submittal for the subject project, the City of Renton Community and Economic Development Department raised a question about why the final design drawings for the outlet control structure do not match the modeling done in the design report. More specifically, the riser in the final design is 18 inches diameter whereas the modeling in the design report indicates a 12 inches diameter riser. Also, the design elevations for the outlet control structure riser elevation, and 2nd orifice elevation are different between the design report and the final design drawings. This supplement to the June 10, 2020 Final Design Report responds to these questions. In general, the response to these questions is that the modeling in the design report reflected “existing” design conditions and not final design conditions. The existing conditions modeling was not updated for design because the project intent was to provide wetpond volume below the existing live storage and otherwise match the existing live storage and outlet control. Because no changes for the detention storage or control was proposed the existing conditions modeling was not updated. The reason why some of the design elevations (riser overflow, and 2nd orifice) do not match the existing pond modeling is because of a modeling simplification used for the existing pond analysis. The existing pond bottom elevation used in the model was 369.32 as a simplification (See assumption on Page 94 of 184 of the design report). This was to be conservative because the existing condition storage was being modeled as a trapezoid volume shape as allowed by the model and elevation 369.32 was the high point of the pond bottom. The existing model also reflects the existing 12-inch diameter riser. For design, it was recommended to increase the riser diameter to 18-inch. This was because the modeling of existing conditions simulated flooding. While the goal of the project was to not change any of the detention storage control, the use of an 18-inch riser was thought to provide a potential modest benefit in flood reduction by increasing the size of the riser. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page i TABLE OF CONTENTS 1 INTRODUCTION .................................................... 1-1 2 BASIN DESCRIPTION ........................................... 2-1 2.1 General .................................................................................... 2-1 2.2 Basin Land Use ...................................................................... 2-1 2.3 Basin Area Soils ..................................................................... 2-1 3 SITE DESCRIPTION .............................................. 3-1 3.1 General .................................................................................... 3-1 3.2 Soils Investigations ................................................................ 3-2 3.3 Site Hydrologic Modeling ...................................................... 3-3 3.4 Proposed Project Features .................................................... 3-4 4 MINIMUM REQUIREMENTS ................................. 4-1 4.1 Minimum Requirement Analysis ........................................... 4-1 5 ALTERNATIVES CONSIDERED ............................ 5-1 5.1 Descriptions of Alternatives Considered ............................. 5-1 5.2 Alternative Comparison and Selection ................................ 5-7 6 DESIGN ANALYSIS ............................................... 6-1 7 QUANTIFY THE WATER QUALITY BENEFIT ....... 7-1 8 ENGINEER’S OPINION OF PROBABLE COST .... 8-1 8.1 Cost Estimate.......................................................................... 8-1 9 PROPOSED SCHEDULE ...................................... 9-1 9.1 Proposed Schedule ................................................................ 9-1 WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page ii City of Renton TABLES TABLE 1 SUMMARY OF HYDROLOGIC MODELING RESULTS .................................................................. 3-3 TABLE 2 ALTERNATIVE EVALUATION SUMMARY ............... 5-7 FIGURES FIGURE 1 VICINITY MAP ........................................................... 1-2 FIGURE 2 EXISTING FACILITY ................................................. 1-3 FIGURE 3 TRIBUTARY BASIN MAP .......................................... 2-3 FIGURE 4 CURRENT ZONING .................................................. 2-5 FIGURE 5 BASIN AREA SOILS MAP ......................................... 2-7 FIGURE 6 ALTERNATIVE 1 ....................................................... 5-3 FIGURE 7 ALTERNATIVE 2 ....................................................... 5-5 FIGURE 8 PIPE SEGMENT REPLACEMENT AT SE 3RD AND UNION AVE SE ................................................. 6-2 APPENDICES A GEOTECHNICAL REPORT B HYDROLOGIC AND HYDRAULIC MODELING C COST ESTIMATES C-1 Alternative 1 Estimate C-2 Alternative 2 Estimate C-3 Final Cost Estimate Schedules A and B D FINAL DESIGN E SEDIMENT TRAP SIZING CALCULATIONS Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 1-1 1 INTRODUCTION The City of Renton (the City) inherited the Heather Downs detention pond through annexation of an unincorporated King County. The pond was built around 1983 and provides flow control for 29.8 acres of residential property. The pond is located at the northeast corner of the intersection of SE 4th Street and Union Avenue SE. A location map is presented as Figure 1. The facility provides little to no water quality treatment. It has no water quality dead storage and is a “back-up” type pond rather than a “flow-through” type pond, which typically provides less water quality treatment (e.g., via sedimentation). Figure 2 presents the existing pond, topography and drainage system in the vicinity of the pond. The pond eventually drains to a pipe system that outfalls to Maplewood Creek and ultimately to the Cedar River, a 303(d) listed waterbody for temperature, pH, fecal coliform, and ammonia. The City successfully obtained grant funds through the Department of Ecology, to retrofit the pond and improve its treatment performance. The City selected Louis Berger to assist in the preparation of a pre-design study, SEPA permitting, and the development of construction plans, specifications, and cost estimate. This report is the first element of the project effort, the pre-design study. The study is intend to follow the Ecology guidance outlined in the Design Deliverables for Stormwater Projects with Ecology Funding (Ecology, June 2018). The objectives of this project are: — To improve water quality treatment performance of the existing Heather Downs detention pond. — Design the stormwater quality retrofit project to meet Ecology’s approval and in accordance with the grant agreement. — Incorporate other opportunities into the project as deemed appropriate by the City, such as replacing portions of damaged fencing around the pond or increasing public awareness/education that may benefit the site or the City’s surface water program. Heather Downs Detention Pond Cedar River Maplewood Creek Lake Washington RentonRenton Mercer IslandMercer Island BellevueBellevue King CountyKing County NewcastleNewcastle KentKent TukwilaTukwila SeattleSeattle Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community 0 1 20.5 Miles ± Vicinity Map Figure 1 Heather Downs Detention Pond Legend Renton City Limits Arterial Road Waterway SDMH 2046RIM=374.48IE 15" CMP W=369.43IE 12" CMP N=368.13IE 24" CONC SE=368.03 2048 SDMH 2048 RIM=374.09 IE 12" CMP SW=369.69 IE 12" CMP S=368.49 IE 12" CONC N=368.06 IE 12" CONC E=367.79 2165 24" CMP W/DEBRIS CAGE IE=368.22 2049 SDMH 2049 RIM=374.01IE 12" PVC NW=367.66 IE 12" CONC E-W=367.58 SDMH 2165 RIM=375.31 TOP 12" VERT CMP O/F SE=373.61 IE=368.01 IE 8" PVC SW=371.61 IE 24" CONC NW=368.01 IE 24" CMP NE=368.01 2047 2045SDCB 2045 TYPE I RIM=373.96 IE 15" CMP E=370.30 2169 SDCB 2047 TYPE IRIM=373.72 IE 8" CMP NE=372.02 2002SDCB 2002 TYPE ISTRUCTURE ROTATION RIM=373.47 IE 12" CMP N=370.34 IE 12" CMP NE= 102 200 101 SDCB 2169 TYPE I RIM=373.64 IE 12" CMP N=370.79 CONC WALKCONC WALKROOTS RAISING CONC WALK2-8", 1-10", 2-12"CEDAR CLUSTER1-8", 2-6", 1-16"CEDAR CLUSTER"NO PARKINGHERE TO CORNER"24"1-12", 1-24" CEDAR ORANGE PAINTED CIRCLE12" STUMPGROUND=374.8'TOP=376.4'8" STUMPGROUND=374.7'TOP=375.0'24" STUMP GROUND=375.7 TOP=377.1' 30" STUMPGROUND=376.9 TOP=378.1'36" STUMPGROUND=377.4'TOP=379.4'36" STUMPGROUND=376.5'TOP=377.7'WV LID=373.87' TOP NUT=372.77'WV LID=373.46' TOP NUT=370.76' WMH LID=373.96' TOP NUT=371.46' TOP PIPE TO N=369.46' DOUBLE 6' CLF SWING GATEDOUBLE 6' CLFSWING GATE6' CLF "STOP" DOUBLE YELLOW LANE MARKERSYELLOW SKIP LANE MARKERSPONDDWY 370370375370 370 376 377375374 374 374 369369374375374374374374374375 373 FL CURB TOP BACK CURB FND 5/8" REBAR, NO CAP SET 5/8" REBAR & CAP, "46878" FND 1/2" REBAR W/WHITE CAP, "B&F INC 12870 & 129XX" (ILLEGIBLE) FND 5/8" REBAR, NO CAP 369 2046 2048 2165 2049 2047 2045 2169 2002 2046 N PLAN FIGURE 2 EXISTING CONDITION HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECT CITY OF RENTON WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 1-4 City of Renton This page left intentionally blank. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 2-1 2 BASIN DESCRIPTION 2.1 GENERAL The basin area for this project is located in southeast Renton on the plateau above the Cedar River. The basin area draining to the Heather Downs Detention facility is dominated by older single family residential land use. Figure 3 shows the basin area, local topography, drainage system, and delineates the three separate subbasins that join together prior to reaching the Heather Downs Detention facility. It also shows a second detention pond within the basin. This second facility is the Fernwood Detention pond. The following paragraphs describe the drainage system and subbasins. — Subbasin 1 consists of approximately 3.65 acres and collects runoff from Union Ave SE and immediate tributary area. It lies on a ridge such that most flow either falls to the east or west, except for immediately adjacent to the road. It includes a piped system that extends south. — Subbasin 2 consists of approximately 5.46 acres and includes a portion of the Fernwood residential subdivision. This area flows to the south and west to the Fernwood Detention pond prior to discharging to the pipe system along Union Avenue SE, and joining flow from Subbasin 1. — Subbasin 3 consists of approximately 19.79 acres and is part of the Heather Downs residential subdivision. Subbasin 3 drains to the south and west to the pipe system along Union Avenue SE where it joins with upstream flows from subbasins 1 and 2. The pipe system continues south to a flow control structure in the Heather Downs pond parcel. The flow control structure contains a “Tee” riser with orifice that backs up flow into the pond. Outflows from the pond discharge to a piped system that extends east and south, eventually outfalling to Maplewood Creek. 2.2 BASIN LAND USE Figure 3 (Tributary Basin Map) presents the current land use of the subbasins using a 2017 aerial photograph. The overall basin is dominated by older single family residential areas. Figure 4 presents the City’s current land use zoning. Nearly all of the area is zoned R-6, which generally allows for 6 dwelling units per acre. It is noted however, that nearly all of the area has a slightly less dense land use of about 4 dwelling units/acre. 2.3 BASIN AREA SOILS Soils Conservation Service soils maps (USDA SCS, 1973) were used to assess soils within the basin and characterize them for the purpose of hydrologic modeling. The soils are presented on Figure 5. The soils mapping indicates that most of the soils are defined as hydrologic group B, with the southeast portion of the basin classified as B/D. The B/D soil classification is considered as soils group C for the purpose of hydrologic modeling. WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 2-2 City of Renton This page left intentionally blank. Heather DownsDetention PondFernwoodDetention PondUnionAveNESE139thStSE 2nd PlSunnydaleMobileHomeParkAcRdChelan Ct NESpruce DrDuvallAveNEFir DrPineRdEvergreenDr141st Ct SESE139thStUnionAveSENE 2nd Pl139th Ave SESE136thPl Fir CirBremertonPlNEBremerton A v e N E BremertonAveNENE 2nd PlH e m lock Dr Berch CtNE2ndStElder CtAlder CtNE 1st CtHickory CtAsh CtFilbert CtElm CtAlder PlLilac CtElmaAveNEPoplar CtYew CtElma Pl SEMapleCtLaurel DrNE1stStNE1stPlOak DrWhitman Ct NERhody DrHemlock DrRedwood DrElmaPlSEC h e l a n A ve S E VashonAveSEWillowDrV a s h o n P l NENE 2nd LnElmaPlNEAnacortesPlNEDuvall Pl SEA n a c o r t e s A v e S E SE 2nd PlDuvallAveSEP rivateRdSE 4th StPrivate RdBremertonAveSEPrivateRdRhodyDrNE 1st PlPrivate RdSE 2nd StNE 1st PlChelanAveNENE 2nd StRosewood DrCedar DrSE 3rd StSE 3rd PlSE 4th PlSE1stPlHemlock DrElmaP lS ESE2nd StVashonP l NEFirCirFirCirVashonCtNEUnionCtNEAnacortesC t NEPrivate RdBASIN2BASIN3BASIN1410400390380350320300250360 3302803402902703703 6 0 3403303 0 0 2 8 0 2 5 0 3 2 0 290 270 35030030028041040041040039038 0370 3603504003 9 0 3503403703102403103502604104104004 1 0 41 0410 4 10 4104104104004004003903 90 390380380370370370370350350 310400 Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS UserCommunity0 300 600150Feet±Tributary Basin MapFigure 3Heather DownsDetention PondLegendSubbasinsParcelsPipeSource: City of Renton GIS WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 2-4 City of Renton This page left intentionally blank. Heather DownsDetention PondFernwoodDetention PondUnionAveNESE139thStSE 2nd PlSunnydaleMobileHomeParkAcRdChelan Ct NESpruce DrDuvallAveNEFir DrPineRdEvergreenDr141st Ct SESE139thStUnionAveSENE 2nd Pl139th Ave SESE136thPl Fir CirBremertonPlNEBremerton Ave N E BremertonAveNENE 2nd PlH e m lock Dr Berch CtNE2ndStElder CtAlder CtNE 1st CtHickory CtAsh CtFilbert CtElm CtAlder PlLilac CtElmaAveNEPoplar CtYew CtElma Pl SEMapleCtLaurel DrNE1stStNE1stPlOak DrWhitman Ct NERhody DrHemlock DrRedwood DrElmaPlSEC h e l a n A ve S E VashonAveSEWillowDrV a s h o n P l NENE 2nd LnElmaPlNEAnacortesPlNEDuvall Pl SEA n a c o r t e s A v e S E SE 2nd PlDuvallAveSEP rivateRdSE 4th StPrivate RdBremertonAveSEPrivateRdRhodyDrNE 1st PlPrivate RdSE 2nd StNE 1st PlChelanAveNENE 2nd StRosewood DrCedar DrSE 3rd StSE 3rd PlSE 4th PlSE1stPlHemlock DrElmaP lS ESE2nd StFirCirFirCirVashonCtNEUnionCtNEAnacortesC t NEPrivate RdBASIN2BASIN3BASIN1R-6R-6R-6R-6R-6R-6R-6RMHR-6R-6R-6R-8R-8R-6R-8R-8R-8R-8R-6R-6R-8R-8R-10R-10R-10R-10R-8R-10ILR-8R-8R-6RCR-8R-10R-8R-8R-8RCR-8R-4R-8R-8R-4 Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS UserCommunity0 300 600150Feet±Current ZoningFigure 4Heather DownsDetention PondLegendSubbasinsPipeZoning DesignationRC-ResourceConservationR4-Residential 4 du/acR6-Residential 6 du/acR8-Residential 8 du/acR10-Residential 10du/acRMH-ResidentialManufactured HomesIL-Industrial - LightSource: City of Renton GIS WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 2-6 City of Renton This page left intentionally blank. Heather DownsDetention PondFernwoodDetention PondAmCAgCAnAkFAkFAkFUnionAveNESE139thStSE 2nd PlSunnydaleMobileHomeParkAcRdChelan Ct NESpruce DrDuvallAveNEFir DrPineRdEvergreenDr141st Ct SESE139thStUnionAveSENE 2nd Pl139th Ave SESE136thPl Fir CirBremertonPlNEBremerton A v e N E BremertonAveNENE 2nd PlH e m lock Dr Berch CtNE2ndStElder CtAlder CtNE 1st CtHickory CtAsh CtFilbert CtElm CtAlder PlLilac CtElmaAveNEPoplar CtYew CtElma Pl SEMapleCtLaurel DrNE1stStNE1stPlOak DrWhitman Ct NERhody DrHemlock DrRedwood DrElmaPlSEC h e l a n A ve S E VashonAveSEWillowDrV a s h o n P l NENE 2nd LnElmaPlNEAnacortesPlNEDuvall Pl SEA n a c o r t e s A v e S E SE 2nd PlDuvallAveSEP rivateRdSE 4th StPrivate RdBremertonAveSEPrivateRdRhodyDrNE 1st PlPrivate RdSE 2nd StNE 1st PlChelanAveNENE 2nd StRosewood DrCedar DrSE 3rd StSE 3rd PlSE 4th PlSE1stPlHemlock DrElmaP lS ESE2nd StVashonP l NEFirCirFirCirVashonCtNEUnionCtNEAnacortesC t NEPrivate RdBASIN2BASIN3BASIN1 Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS UserCommunity0 300 600150Feet±Basin Area Soils MapFigure 5Heather DownsDetention PondLegendSubbasinsPipeHydrologic Soil GroupABB/D (Considered asType C for Modeling)Source: USDA Web Soil Survey WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 2-8 City of Renton This page left intentionally blank. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 3-1 3 SITE DESCRIPTION 3.1 GENERAL This section presents a site description based on study investigations and available information. The approximate 0.19-acre site is located on the northeast corner of the intersection of Union Avenue SE and SE 4th Street. An existing detention pond covers nearly the entire site. The pond is fenced and has approximately 1H:1V side slopes. Several trees are along the perimeter. Figure 2 presents the site’s topography and drainage system. The basin tributary to the pond is conveyed south through a 12-inch diameter pipe to the southwest corner of the pond. A control structure is located at this location which has an orifice and riser. A 24-inch pipe extends to the pond. Flows are controlled by the restrictor and “back-up” into the pond during high flow. The pond was constructed around 1983. The main access into the pond is at its northwest edge off of Union Avenue SE. The access road is steep at 4H:1V, which does not meet current City standards. The pond is five to six feet deep and is adjacent to two residential lots. The pond is generally covered in grasses and has several trees along its outer edge. In addition there are tree stumps along the outer edge that have been cut down to roughly ground level. The pond side slopes and bottom are vegetated with grasses. Photographs 1 and 2 on the following page show the pond conditions. Photo 1 – looking north at pond interior Photo 2 – looking northeast at pond exterior (southwest corner of pond) WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 3-2 City of Renton 3.2 SOILS INVESTIGATIONS A soils investigation was completed to assess site soil conditions and provide soils recommendations for project design and construction. A copy of the draft geotechnical report is included in Appendix A. To assess site conditions, 2 borings were installed (BH-1 and BH-2) to depths of 13 and 18 feet, respectively, where they encountered auger refusal and (indicated very stiff soils) and could not extend further. A monitoring well was installed in BH-2. An electronic data logger transducer was installed in the well and set to record ground water level every 5 minutes from February 27 to May 13, 2019. Soils recovered from the borings were tested for moisture content and particle size distribution. A summary of the soil investigation results, conclusions and recommendations are presented in the following paragraphs. Refer to Appendix A for additional information. — Subsurface Soil Description: The soils encountered in the explorations consist of near surface fill soils over native, glacial outwash deposits. Further descriptions of soils encountered in our explorations are presented. Near-surface soils included a layer of fill which was encountered in boring BH-2 from ground surface to approximately 2.5 feet below ground surface (bgs). The fill consisted of medium dense, silty sand. The fill was likely placed for the access road during past construction operations in the area. BH-1 did not encounter fill. Below the fill was glacial advance outwash. The outwash typically consisted of dense to very dense, gravelly, slightly silty to silty, sand. The upper 4 to 8 feet of the outwash deposit was weathered and slightly less dense. — Groundwater: Perched ground water was observed in both borings. Boring BH-1 (surface elevation 369 feet) encountered ground water seepage from 4-6 feet bgs (approximate Elevation 363 to 365 feet). Boring BH-2 (surface elevation 374 feet) encountered ground water seepage from 8-10 feet bgs (Elevation 364 to 366 feet). The ground water was observed to be perched over the very dense advance outwash layer. Shallow standing (ponded) water was observed in the detention pond at the time of drilling, likely a result of recent snow/rain. The ground water level at the monitored BH-2 was observed to vary between approximately 7.8 and 13.3 feet bgs (approximate Elevation 361.7 to 367.2 feet). It is expected that the ground water levels across the site vary seasonally in response to precipitation. — Infiltration Potential: Infiltration as a potential pond improvement is very limited due to the presence of relatively impermeable materials observed within 4 to 6 feet bgs and also, because of the existing groundwater level (approximate Elevation 364 feet), there is not sufficient separation between the bottom of pond and ground water level to rely upon infiltration. Additionally, if the pond is deepened by 3 to 6 feet, excavation will likely intercept the locally perched water level. This may result in standing (ponded) water at the new pond bottom but will not affect the local ground water level. — Slope Stability: Analysis was done to assess the current relatively steep side slope of 1H:1V. A seismic analysis was completed and concluded that the slopes are stable. The report also recommends not removing the existing stumps as they may provide additional slope stability. An analysis was also completed to assess what would be an acceptable slope for a potential wetpond excavated below the current pond bottom. The conclusion was that a 2H:1V would be acceptable and would not need any stability where the existing 1H:1V slope transitions to a new 2H:1V slope. — Additional Considerations for a Proposed Wetpond: One design consideration for a water quality wetpond at the site, is that it is desirable for wetponds to have a permanent pool level throughout the year, particularly in the wet season. City design standards indicate that wetponds are considered non-compliant if the pond level drops more than 12-inches in any 7-day measurement period during the wet season. The groundwater monitoring showed that the measured groundwater level varied over 5 feet during the monitored time period. As a result, a pond liner is recommended. — Construction: Recommendations were provided for any required fill, excavation and wet weather work for construction. Refer to Appendix A for details. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 3-3 3.3 SITE HYDROLOGIC MODELING Ecology’s stormwater hydrologic model (WWHM2012) was developed to simulate existing hydrology of the basin as well as pond inflows/outflows and water quality information. The three subbasins were included in the model and flows were routed to the Heather Downs detention pond. Subbasin 2 was routed through the Fernwood pond with outflows joining the flow from Subbasin 1. Information on the model development is included in the following paragraphs. — Soils classifications were taken from the USDA Natural Resources Conservation Service website that provide soil type and hydrologic classification (https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx). Basin soils were described previously and presented on Figure 5. — The percent of impervious area was estimated based on the methods presented in the 2016 King County Surface Water Design Manual (KCSWDM). These methods recognize that not all impervious area directly connects to the drainage system. For example, residential areas often have with rooftops, paths, driveways or sheds that drain to splash pads, lawns or landscaping. A portion of such drainage can then be infiltrated into the underlying soil or lost to evapo-transpiration. These areas are treated as the non-effective impervious areas and are assumed to have the same hydrologic characteristics as lawn. The KCSWDM includes common factors to estimate the percentage of impervious area that is effective (typically less dense land uses have lower percentage of effective impervious area). Appendix B includes a summary table estimating the effective imperious areas for each basin. — Pervious cover types were developed using GIS, soils, and slope information. All pervious cover types assume “lawn” for this analysis. — Pond routing tables were based upon available information. The study survey was used to develop stage-storage information for the Heather Downs pond, with the exception that the 1983 record drawings were used to determine the outlet control orifice size (since this could not be observed during the recent site survey). It is noted that the current site survey and the 1983 design drawings are at different elevation datums. City-provided design drawings of the Fernwood development were used for the Fernwood Pond (included in Appendix B). To estimate the water quality treatment volume that would be required, existing land use was used. This volume reflects how much wetpond volume would be required to retrofit the tributary area to meet current design standards. A summary of the water quality results are as follows (and are taken from the “Heather Downs Pond Water Quality Volume and Flow Sheet in Appendix B): — Water Quality Flow Volume: 1.11 ac-ft (this is based on existing land use) — Water Quality (on-line) flow rate: 0.64 cfs — Water Quality (off-line) flow rate: 0.38 cfs It is also noted that the Fernwood pond is not simulated to overflow (based on the Peak Stage Results Sheet in Appendix B). The Heather Downs Detention Pond Simulation Results are shown in Table 1. The results include the simulated peak pond inflows and outflows for various recurrence intervals as well as a maximum simulated water surface elevation. Table 1 Summary of Hydrologic Modeling Results STORM PEAK INFLOW (CFS) (FROM APPENDIX B PEAK FLOW RESULTS SHEET) PEAK OUTFLOW (CFS) (FROM APPENDIX B PEAK FLOW RESULTS SHEET) MAX. SIMULATED WSE (FT) (FROM APPENDIX B PEAK STAGE RESULTS SHEET) RISER OVERFLOW (AT ELEV. 373.61)? (Y/N) 2-year 4.2 1.9 374.0 Y 10-year 6.7 4.1 374.5 Y 25-year 8.1 5.2 374.8 Y 50-year 9.3 6.1 375.2 Y 100-year 10.6 6.9 375.3 Y WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 3-4 City of Renton Additional observations include: — The Heather Downs Pond is simulated to go into riser flow for all events (having a new emergency overflow may help this). — The peak flow results at the inflow location to the Heather Downs detention pond suggests that the existing 12-inch diameter pipe would be surcharged and there could be “gutter” flow. The 12-inch diameter pipe along Union Ave SE has a normal flow capacity of about 5.5 cfs (based on manning’s equation (with Manning’s n = 0.012 for concrete and uniform pipe slope of 2%). Estimated peak flows range from 4.2 cfs (2-yr) to 10.6 cfs (100 year). Thus, flow would be expected along gutter line during extreme floods. However, there are no specific reports of flooding on this side of the street. The City will consider future analysis and potential upsizing of this system, but did not want to incorporate that element of the work into the current project. However, improvements will be considered during design to upsize those elements of the conveyance system where improvements are made so they will not be undersized once future off-site conveyance improvements are implemented. A complication of this system analysis is that high water level conditions in the pond create backwater effects on the upstream system. It is recommended that the City monitor the site during significant storm events to provide some validation of the suspected flooding. — The pond is simulated to overtop for the 2-year event. The City has not reported frequent pond overtopping. Thus, it is anticipated that the model somewhat overpredicts flood flow events. As the focus of this study is on the more frequent events associated with water quality treatment, no modeling adjustments were made. 3.4 PROPOSED PROJECT FEATURES Proposed project features generally include converting the “back-up” type detention pond to a “flow-through” combination wetpond/detention pond. The City does not want to reduce the detention storage provided by the facility and so any expansion would be created by excavating below the currently live storage volume. Various alternative configurations of pond expansion are discussed later in this report. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 4-1 4 MINIMUM REQUIREMENTS 4.1 MINIMUM REQUIREMENT ANALYSIS The project must comply with the City of Renton’s 2016 Surface Water Design Manual, a stormwater design manual equivalent to Ecology’s Surface Water Management Manual for Western Washington. In general, the project is not proposing to create any new pollution generating or non-pollution generating impervious surfaces. A minor square footage (less than 100 sf) of replaced impervious surfaces will be require to install a pipe system connection to the pond off Union Avenue SE. To establish the drainage review type, Figure 1.1.2.A of the Renton manual was consulted. This flow chart figure guides users through a decision tree to determine the applicable drainage review type. The drainage review type then defines what core requirements must be met. The following assumptions were used to apply the flow chart to this project: — Project is not a Single-Family Residential Project. — Project does not result in >/= of 2,000 sf of new plus replaced impervious surfaces or >/= 7,000 sf of land disturbing activity. This is based upon two considerations. First, per the manual definitions, open, uncovered retention/detention facilities shall not be considered impervious surfaces for purposes of determining whether the thresholds for application of minimum requirements are exceeded. Second, the disturbed area, mostly including the area below the existing pond bottom footprint is < 7,000 sf. — Project does propose to construct/modify a drainage pipe 12-inch diameter or greater. — Project is within Zone 2 of the City of Renton Aquifer Protection Area. Based on these assumptions, the project requires a Category 1 Targeted Review. This review results in the following requirements be applicable to this project: — Core Requirement #1: Discharge at the Natural Location. — Core Requirement #2: Offsite Analysis. — Core Requirement #3: Flow Control Facilities. — Core Requirement #4: Conveyance System. — Core Requirement #5: Erosion and Sediment Control — Core Requirement #6: Maintenance and Operations — Core Requirement #7: Financial Guarantees and Liability — Core Requirement #8: Water Quality Facilities The following paragraphs provide a summary of the project’s approach to meeting the requirement: — Core Requirement #1: Discharge at the Natural Location. The project will not change the discharge location. Pond outflows will be directed to the existing pipe system. — Core Requirement #2: Offsite Analysis. The pond outfalls to a 12-inch diameter pipe system in SE 4th Street. It extends east to SE 4th Place, where it continues approximately 300 feet before veering south in a drainage easement to outfall to a steep drainage that ultimately joins with Maplewood Creek. Maplewood Creek flows south and west to join with the Cedar River, a 303(d) listed waterbody for temperature, pH, fecal coliform, and ammonia. No detailed field review of the downstream system was undertaken, in part because no changes are being proposed to the conveyance system and the project will only improve water quality. — Core Requirement #3: Flow Control Facilities. The project is a retrofit project to modify a flow control facility by modifying it to combined flow control/water quality facility. The City will not reduce the detention storage provided by the existing facility and will not create new impervious area. Therefore, no new flow control facility or added storage is required. — Core Requirement #4: Conveyance System. Modeling was completed as previously described in this section. Modeling of the system indicates that the 12-inch diameter pipe system along Union Avenue SE may not meet current conveyance standards. In addition, the Heather Downs detention pond is simulated to be in overflow. However, as a water quality WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 4-2 City of Renton retrofit project, the City is not required to fully meet the current standard. The City will consider future analysis and potential upsizing of this system, but did not want to incorporate that element of the work into the current project. However, improvements will be considered during design to upsize those elements of the conveyance system where improvements are made so they will not be undersized once future off-site conveyance improvements are implemented. Such conveyance improvement may require a City of Renton Stormwater Adjustment Request through the City’s Community and Economic Development Department (CED) to document the approach. — Core Requirement #5: Erosion and Sediment Control. Detailed temporary erosion control drawings will be developed as a part of the project design and will become a part of the construction contract. — Core Requirement #6: Maintenance and Operations. The City of Renton is the owner of the facility and will continue to provide maintenance through the City’s Roads Maintenance Department. — Core Requirement #7: Financial Guarantees and Liability. The City of Renton is ultimately responsible for guaranteeing financial liability on the project and the standard guarantees and liability forms for private development do not apply. — Core Requirement #8: Water Quality Facilities. The primary objective of the project is to enhance stormwater quality treatment. However, it is noted that as a retrofit project, it will not need to meet treatment standards for the entire tributary basin. For this project an analysis was conducted to determine the water quality benefit provided by the project. This required the development of an estimate for the water quality treatment volume for the facilities tributary area as well as the water quality treatment volume provided by the project. This is discussed under Section 7. The project must also consider special requirements. These include; — Special Requirement #1: Other Adopted Area-Specific Plans. — Special Requirement #2: Flood Hazard Area Delineation. — Special Requirement #3: Flood Protection Facilities. — Special Requirement #4: Source Controls. — Special Requirement #5: Oil Control — Special Requirement #6: Aquifer Protection Area Special requirements 1 through 5 do not apply to this project. The project does lie within Zone 2 of the Aquifer Protection Area and as a result Special Requirement #6 must be considered for project improvements. This is discussed in Section 6. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 5-1 5 ALTERNATIVES CONSIDERED 5.1 DESCRIPTIONS OF ALTERNATIVES CONSIDERED This section includes a discussion of alternatives considered including those that are evaluated in detail and those that were not selected for detailed analyses. Two alternatives were selected for detailed analysis. These are referred to as Alternative 1 and Alternative 2. They both include converting the pond from a “back-up” type detention pond to a “flow-through” type combined wetpond/detention pond. The two alternative vary in terms of depth and whether one or two cells are created. Alternative 1 – This alternative is presented on Figure 6. It includes a two-cell pond with an access road that divides the cells. The first cell has a wetpool depth of 4.2 feet. Ideally, it would be deeper, however, grades made this difficult. It is assumed that the City can maintain the first cell from the top of the access road. The second cell has a depth of 5.2 feet. The north slope of the cell was set at a slope of 5H:1V. This is to allow maintenance access to the bottom of the second cell. This does not meet the City standard access road slope of 7H:1V, however, this slope could not be achieved due to grades. Overall this alternative creates approximately 0.14 ac-ft of new wetpond storage. Alternative 2 – This alternative is presented on Figure 7. It includes a one-cell pond. By eliminating the bench for the two-cell configuration, this pond provides better access to the entire pond bottom. It was assumed that the access road would be set at a slope of 5H:1V. Anything less steep is difficult to the limited space. To meet grades and have access to the entire pond bottom, the wetpool is shallower than that presented in Alternative 1, at a depth of 3.2 feet. Overall this could create 0.17 ac-ft of new wetpond storage. ALTERNATIVES NOT CONSIDERED IN DETAIL. — Some consideration was given to creating more storage using an underground vault that could be constructed below the bottom of the pond. This approach was not considered favorable because of cost, more difficult maintenance, and because there could be some loss of volume efficiency should it be determined that the vault need to be covered with vegetation. This latter reason is because the vault cover material and thickness of the top slab would mean that the new volume of wetpond volume would not begin until a few feet below the existing pond grade. — Some consideration was given to using a short wall around the perimeter of the pond to increase storage (e.g. an Ecology block wall with 1 or 2 blocks in height). However, preliminary stability analysis by the design team’s geotechnical engineer concluded that a block wall at the toe of the slope would not have the recommended stability factor of safety. In addition, it would add costs and not likely increase volume dramatically. — Use of a proprietary filter system for water quality treatment was initially considered. However, any type of system would have to be located on the pond parcel and it would likely take up storage volume that is currently used for detention storage. The City does not want to reduce storage for quantity control, in part because the downstream system is already simulated to be undersized. In addition, this would result in added capital costs and operation and maintenance costs. WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 5-2 City of Renton This page left intentionally blank. SDMH 2046RIM=374.48IE 15" CMP W=369.43IE 12" CMP N=368.13IE 24" CONC SE=368.03 2048 SDMH 2048 RIM=374.09 IE 12" CMP SW=369.69 IE 12" CMP S=368.49 IE 12" CONC N=368.06 IE 12" CONC E=367.79 2165 24" CMP W/DEBRIS CAGEIE=368.22 2049 SDMH 2049 RIM=374.01 IE 12" PVC NW=367.66 IE 12" CONC E-W=367.58 SDMH 2165 RIM=375.31 TOP 12" VERT CMP O/F SE=373.61 IE=368.01 IE 8" PVC SW=371.61 IE 24" CONC NW=368.01IE 24" CMP NE=368.01 2047 2045SDCB 2045 TYPE IRIM=373.96 IE 15" CMP E=370.30 2169 SDCB 2047 TYPE I RIM=373.72 IE 8" CMP NE=372.02 2002SDCB 2002 TYPE I STRUCTURE ROTATION RIM=373.47IE 12" CMP N=370.34 IE 12" CMP NE= 102 200 101 SDCB 2169 TYPE I RIM=373.64 IE 12" CMP N=370.79 CONC WALKCONC WALKROOTS RAISING CONC WALK2-8", 1-10", 2-12"CEDAR CLUSTER1-8", 2-6", 1-16"CEDAR CLUSTER"NO PARKINGHERE TO CORNER"24"1-12", 1-24" CEDAR ORANGE PAINTED CIRCLE12" STUMPGROUND=374.8'TOP=376.4'8" STUMPGROUND=374.7'TOP=375.0'24" STUMPGROUND=375.7 TOP=377.1' 30" STUMP GROUND=376.9 TOP=378.1'36" STUMPGROUND=377.4'TOP=379.4'36" STUMPGROUND=376.5'TOP=377.7'WV LID=373.87' TOP NUT=372.77'WV LID=373.46' TOP NUT=370.76' WMH LID=373.96'TOP NUT=371.46' TOP PIPE TO N=369.46' DOUBLE 6' CLF SWING GATEDOUBLE 6' CLFSWING GATE6' CLF "STOP" DOUBLE YELLOW LANE MARKERSYELLOW SKIP LANE MARKERSPONDDWY 370370375370 370 376 377375374 374 374 369369374375374374374374374375 373 FL CURBTOP BACK CURB FND 5/8" REBAR, NO CAP SET 5/8" REBAR & CAP, "46878" FND 1/2" REBAR W/WHITE CAP, "B&F INC 12870 & 129XX" (ILLEGIBLE) FND 5/8" REBAR, NO CAP 369 2046 2048 2165 2049 SDMH 2049 RIM=374.01 IE 12" PVC NW=367.66 IE 12" CONC E-W=367.58 2047 2045 2169 2002 SDCB 2169 TYPE I RIM=373.64 IE 12" CMP N=370.79 2046 SDMH 2048 RIM=374.09 IE 12" CMP SW=369.69 IE 12" CMP S=368.49 IE 12" CONC N=368.06 IE 12" CONC E=367.79 SDMH 2165 RIM=375.31 TOP 12" VERT CMP O/F SE=373.61 IE=368.01 IE 8" PVC SW=371.61 IE 24" CONC NW=368.01IE 24" CMP NE=368.01 SDCB 2045 TYPE IRIM=373.96 IE 15" CMP E=370.30 SDCB 2047 TYPE I RIM=373.72 IE 8" CMP NE=372.02 SDCB 2002 TYPE I STRUCTURE ROTATION RIM=373.47IE 12" CMP N=370.34 IE 12" CMP NE= SDMH 2046RIM=374.48 IE 15" CMP W=369.43 IE 12" CMP N=368.13 IE 24" CONC SE=368.03 FIGURE 6 ALTERNATIVE 1 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECT CITY OF RENTON N PLAN SECTION A-A CONSTRUCTION NOTES WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 5-4 City of Renton This page left intentionally blank. SDMH 2046RIM=374.48IE 15" CMP W=369.43IE 12" CMP N=368.13IE 24" CONC SE=368.03 2048 SDMH 2048 RIM=374.09 IE 12" CMP SW=369.69 IE 12" CMP S=368.49 IE 12" CONC N=368.06 IE 12" CONC E=367.79 2165 24" CMP W/DEBRIS CAGE IE=368.22 2049 SDMH 2049 RIM=374.01 IE 12" PVC NW=367.66 IE 12" CONC E-W=367.58 SDMH 2165 RIM=375.31 TOP 12" VERT CMP O/F SE=373.61 IE=368.01 IE 8" PVC SW=371.61 IE 24" CONC NW=368.01 IE 24" CMP NE=368.01 2047 2045SDCB 2045 TYPE I RIM=373.96 IE 15" CMP E=370.30 2169 SDCB 2047 TYPE I RIM=373.72 IE 8" CMP NE=372.02 2002SDCB 2002 TYPE I STRUCTURE ROTATION RIM=373.47 IE 12" CMP N=370.34 IE 12" CMP NE= 102 200 101 SDCB 2169 TYPE I RIM=373.64 IE 12" CMP N=370.79 CONC WALKCONC WALKROOTS RAISING CONC WALK2-8", 1-10", 2-12"CEDAR CLUSTER1-8", 2-6", 1-16"CEDAR CLUSTER"NO PARKINGHERE TO CORNER"24"1-12", 1-24" CEDAR ORANGEPAINTED CIRCLE12" STUMPGROUND=374.8'TOP=376.4'8" STUMPGROUND=374.7'TOP=375.0'24" STUMP GROUND=375.7 TOP=377.1' 30" STUMP GROUND=376.9 TOP=378.1'36" STUMPGROUND=377.4'TOP=379.4'36" STUMPGROUND=376.5'TOP=377.7'WV LID=373.87' TOP NUT=372.77'WV LID=373.46'TOP NUT=370.76' WMH LID=373.96' TOP NUT=371.46' TOP PIPE TO N=369.46' DOUBLE 6' CLF SWING GATEDOUBLE 6' CLFSWING GATE6' CLF "STOP" DOUBLE YELLOW LANE MARKERSYELLOW SKIP LANE MARKERSPONDDWY 370370375370 370 376 377375374 374 374 369369374375374374374374374375 373 FL CURB TOP BACK CURB FND 5/8" REBAR, NO CAP SET 5/8" REBAR & CAP, "46878" FND 1/2" REBAR W/WHITE CAP, "B&F INC 12870 & 129XX" (ILLEGIBLE) FND 5/8" REBAR, NO CAP 369 2046 2048 2165 2049 SDMH 2049 RIM=374.01 IE 12" PVC NW=367.66 IE 12" CONC E-W=367.58 2047 2045 2169 2002 SDCB 2169 TYPE I RIM=373.64 IE 12" CMP N=370.79 2046 SDMH 2048 RIM=374.09 IE 12" CMP SW=369.69 IE 12" CMP S=368.49 IE 12" CONC N=368.06 IE 12" CONC E=367.79 SDMH 2165 RIM=375.31 TOP 12" VERT CMP O/F SE=373.61 IE=368.01 IE 8" PVC SW=371.61 IE 24" CONC NW=368.01 IE 24" CMP NE=368.01 SDCB 2045 TYPE I RIM=373.96 IE 15" CMP E=370.30 SDCB 2047 TYPE I RIM=373.72 IE 8" CMP NE=372.02 SDCB 2002 TYPE I STRUCTURE ROTATION RIM=373.47 IE 12" CMP N=370.34 IE 12" CMP NE= SDMH 2046 RIM=374.48 IE 15" CMP W=369.43IE 12" CMP N=368.13 IE 24" CONC SE=368.03 CONSTRUCTION NOTES N PLAN SECTION A-A FIGURE 7 ALTERNATIVE 2 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECT CITY OF RENTON WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 5-6 City of Renton This page left intentionally blank. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 5-7 5.2 ALTERNATIVE COMPARISON AND SELECTION To select the recommended alternative, the consultant team, working with City staff, developed an alternative summary comparison. Evaluation criteria included costs, water quality treatment performance, maintenance considerations, and other advantages and disadvantages. Planning level cost estimates were developed for the alternatives by estimating construction quantities and applying the consultant team’s knowledge of current unit contract pricing of common construction items. Cost estimates include a construction contingency of 40 percent as well as other cost allowances including, administrative costs, and construction management/inspection. Cost estimates are located in Appendix C. Water quality treatment performance for the two alternatives were estimated using Ecology procedures outlined in Design Deliverables for Stormwater Projects with Ecology Funding (June, 2018). This procedure defines the water quality benefit for a volume based treatment facility by determining the ratio of water quality volume provided (by the improvement) over the volume that would be required to meet current standards for the tributary area. The volume required to meet current standards is based upon current land use. Table 2 Alternative Evaluation Summary ALT. # COST ESTIMATE WATER QUALITY BENEFIT (RATIO OF WETPOOL VOLUME PROVIDED / WETPOOL VOLUME THAT WOULD BE REQUIRED FOR ENTIRE BASIN) MAINTENANCE CONSIDERATIONS ADVANTAGES DISADVANTAGES 1 $218,000 0.127 - Maintenance access to the first cell is assumed to be via the top of the berm. This alternative appears less favorable in terms of pond access. - Converts a “back-up” type pond to a “flow-through” type pond - Has two cells with first cell likely capturing larger sediment. - Smaller overall volume provided than Alt#2 - Access to 1st cell not ideal. Less space for vehicle maneuver. 2 $219,000 0.153 - Because the access is provided for the entire pond, it is comparatively easier to maintain this single cell pond. - More space for vehicles to maneuver - Converts a “back-up” type pond to a “flow-through” type pond - Ease of construction & maintenance as compared with Alt#1. - More storage volume is provided compared to Alt#1. - Less dewatering of groundwater during construction compared to Alt#1. - Does not include the typically two-cell configuration. WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 5-8 City of Renton Based on this evaluation, Alternative 2 is recommended. Factors considered in this selection include: — Alternative 2 would provide approximately 20% more water quality volume at roughly the same costs. This likely results in some water quality benefit over Alternative 1. — Alternative 2 would provide easier access for maintenance. The pre-settling cell for Alternative 1 may be hard to maintain without impacting the liner (assuming a bucket would be used for cleaning from the berm between the two cells). — While alternative 2 does not include the typical two-cell arrangement for a wetpond, the lack of an initial cell may not be a significant concern. This is in part because the full wetpond volume provided for this alternative, when compared to what would be required for the entire tributary basin is a relatively small fraction. Thus having an initial cell would not likely meet its intended objective because it would be undersized. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 6-1 6 DESIGN ANALYSIS After review of the two (2) alternatives, the City confirmed that Alternative 2 is the preferred approach. It will convert the “back-up” type dry detention pond to a “flow-through” one-call combined wetpond/detention pond, with a wetpond depth of 3.2 feet. The geometry of the existing pond with is generally retained except that the access road will be improved at a flatter slope, going from 4H:1V to 5H:1V. The combination of converting the pond to a “flow-through” type and creating the wetpond cell will improve its treatment performance. The applicable Ecology BMP type is referred to as BMP T10.40 in Ecology’s Stormwater Manual for Western Washington, although with some difference as this project will be a retrofit and will not meet all of the requirements (e.g. one-cell pond instead of two-cell, and undersized for the tributary basin). As explained in Section 5, the one-cell pond is considered to be more efficient and better for maintenance considerations when compared with the two-cell pond. The pond improvements would improve treatment for the runoff from the 29.8 acre basin. A preliminary 90% design drawing set for Alternative is included in Appendix D. No new model simulations were developed for the recommended alternative, as the model was primarily used to assess water quality benefit. The water quality benefit is further described in Section 7. To address location in Zone 2 of the City’s Aquifer Protection Area, the pond bottom will be lined with a low permeability liner. The City stormwater design manual allows for several low permeable liner options. These include a compacted till liner, clay liner, geomembrane liner, and a concrete liner. Of these four options, a compacted till liner is recommended. A soil-type liner is preferred over concrete and geomembrane due to cost and ease of installation. Till is recommended over clay in part because the clay liner is not allowed on a slope greater than 3H:1V. Based on input from the geotechnical team member, the till liner at a 2H:1V slope is acceptable provided it is compacted in 6-inch lifts and has a layer of compost amended soil above the liner. The liner is proposed to include the wetpond area plus an additional foot up the pond side slope. It is noted that this currently would not meet the City’s standard design requirement of lining up to the 2-year event, but this creates several challenges with the existing over-steepened slopes. As a result the Surface Water Utility prepared a Stormwater Adjustment Request which has been approved. It is also noted that the liner could be subject to some uplift forces during periods of high groundwater. This should not be a concern because the downward weight of the water contained in wetpond. However, any dewatering (i.e., pump-out) of the wetpond for maintenance should be conducted during a period when groundwater is near the bottom of the pond (mid-summer to early fall). Following the 60% design submittal, one concern brought up by the City Operations and Maintenance group was maintenance of the existing pond side slopes above the proposed wetpond surface (which are steep at nearly 1 horizontal to 1 vertical). To address this the 90% design included added a narrow bench (e.g., 3 feet) above the wetpond surface for access for a person with a “weedwhacker” to walk around the base of the pond side slopes. This resulted in some loss of storage volume for the wetpond (compared to the alternative analysis). The new estimated treatment volume is 0.114 ac-ft. During the design development, the City completed CCTV of the segment of 12-inch diameter storm drain along SE 4th Street from near the south edge of the pond north to SE 3rd Place. It was noted that an approximately 10 foot section of pipe (the first 10 feet of pipe connecting to MH 131870 and extending south) had settled. In addition, several of the drain laterals were in very poor condition. As a result the City elected to do these pipe replacements as a part of the overall project because of their close proximity to each other. The limited pipe replacement work will be added to the project. It will not be eligible for the Ecology grant funding and the City will make it a separate bid schedule. A sketch of this segment of pipe is shown below in Figure 8. WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 6-2 City of Renton Figure 8 Pipe Segment Replacement at SE 3rd and Union Ave SE Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 7-1 7 QUANTIFY THE WATER QUALITY BENEFIT This section includes the estimate of the water quality benefit following the procedures outline in Section D of Ecology’s Design Deliverables for Stormwater Projects with Ecology Funding. These include calculations for the water quality benefit and calculations for the flow control benefit. These are described below. WATER QUALITY BENEFIT — The basin tributary to the pond is 29.8 acres, which includes 3 subbasins. — The existing impervious area was estimated at 8.64 acres (30% impervious) — For these conditions and applicable pervious soils, WWHM was used to calculate the required water quality treatment volume for the entire basin at 1.11 acre-ft. (the modeling is contained in Appendix B – Hydrologic and Hydraulic Modeling (page 21 of the WWHM report). — The water quality benefit ratio is estimated based on the treatment volume provided by the retrofit divided by the what treatment volume would be required for the entire basin. The treatment volume provided by the pond based upon the 90% design is 0.114 ac-ft, so the calculated benefit ratio is to be 0.103 for the proposed retrofit. — The resulting estimate for the Equivalent New/Redeveloped Areas (equal to the water quality ratio multiplied by the contributing basin area) is 3.1 acres. FLOW CONTROL BENEFIT — The flow control benefit is generally defined as the proposed detention volume provided by the retrofit divided by the volume that would be required to meet the redevelopment criteria (assuming forested conditions for the tributary basin). — For this project, no added flow control facility volume is proposed. All new volume is used for the water quality wetpond. Thus, the flow control benefit would be zero. — With the flow control benefit of zero, the equivalent redevelopment area for flow control would also be zero. WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 7-2 City of Renton This page left intentionally blank. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 8-1 8 ENGINEER’S OPINION OF PROBABLE COST 8.1 COST ESTIMATE Cost estimates for the alternatives were discussed in Section 5 and included in Appendix C. The cost estimates for the recommended alternative was updated and estimated to be $409,000 for the 90% design. The update included further analysis of typical unit bid prices to comment construction items. This was based on reviewing bid tabulations for similar type projects in recent years. The 90% cost estimate includes City project administration, construction management and inspection and a 25% construction contingency. The format of the estimate was developed to be in accordance with potential grant opportunities. In general, the cost estimate for the 90% design increased from earlier cost estimates because the alternative estimates did not include the low permeability liner and because of the added pipe replacement at 3rd Place SE. A copy of the updated estimated is included at the end of Appendix C. The 90% cost estimate is broken down in to two bid schedules, one that reflects the grant eligible work of the pond retrofit and one that is not grant eligible work of the pipe replacements. Schedule A, including the pond retrofit work is was estimated to be $307,000 of the overall project cost. This cost will be eligible for grant funding. Following the 90% Pre-design Report submittal, a final cost estimate was prepared using the bid items included in final design in accordance with the City’s standard bid schedule format. This cost estimate, also included in Appendix C is estimated at $268,000 which only includes construction (Schedule A and B) and does not include a construction contingency nor project administration and construction management. WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 8-2 City of Renton This page left intentionally blank. Final Design Report WSP Heather Downs Detention Pond Water Quality Retrofit Project June 10, 2020 City of Renton Page 9-1 9 PROPOSED SCHEDULE 9.1 PROPOSED SCHEDULE A preliminary project schedule is presented on the following page. The schedule includes allowances for Ecology review time as well as time for the City and Ecology to negotiate a grant should the City be successful in applying for a water quality retrofit grant. The City hopes to go to bid early in 2021 and construct the facility in the summer of the same year. WSP Final Design Report June 10, 2020 Heather Downs Detention Pond Water Quality Retrofit Project Page 9-2 City of Renton This page left intentionally blank. IDTask ModeTask Name Duration Start Finish1NTP1 day?Tue 1/29/19Tue 1/29/192DESIGN PHASE (CURRENTLY GRANT FUNDED671 days?Wed 1/30/19Tue 8/24/213Task 1 ‐ Project Management260 daysWed 1/30/19Mon 1/27/204Task 2 ‐ Data Collection/Review10 daysWed 1/30/19Tue 2/12/195Task 3 ‐ Topographic Survey16 daysWed 2/13/19Wed 3/6/196Task 4 ‐ Geotechnical Report25 daysWed 2/13/19Tue 3/19/197Task 5 ‐ Design Report140 daysThu 3/7/19Tue 9/17/198Task 5.1 ‐ H/H Modeling10 daysThu 3/7/19Wed 3/20/199Task 5.2 Alt. Identification and Analysis20 daysThu 3/21/19Wed 4/17/1910Task 5.3 ‐ Design Report Submittals110 daysThu 4/18/19Tue 9/17/1911Task 5.3 A ‐  Draft Submitta35 daysThu 4/18/19Wed 6/5/1912Task 5.3 B ‐ City Review10 daysThu 6/6/19Wed 6/19/1913Task 5.3 C ‐ Ecology Submit5 daysThu 6/20/19Wed 6/26/1914Task 5.3 D ‐ Ecology Review45 daysThu 6/27/19Wed 8/28/1915Task 5.3 E ‐ Final Submittal15 daysThu 8/29/19Tue 9/17/1916Task 6 ‐ SEPA Checklist Review 5 daysWed 9/18/19Tue 9/24/1917Task 7 ‐ Design, Construction Documents1 day?Wed 9/25/19Wed 9/25/1918Task 7.1 ‐ 50‐60% Submittal35 daysThu 4/18/19Wed 6/5/1919Task 7.2  ‐ 90% Submittal75 daysWed 9/18/19Tue 12/31/1920Task 7.2 A ‐  90% Submittal to City/Ecology30 daysWed 9/18/19Tue 10/29/1921Task 7.2 B ‐ City/Ecology Revie45 daysWed 10/30/1Tue 12/31/1922Task 7.3 ‐ Final Bid Ready Submittal55 daysWed 1/1/20Tue 3/17/2023Task 7.3 A ‐ Final Submittal toCity/Ecology25 daysWed 1/1/20Tue 2/4/2024Task 7.3 B ‐ City/Ecology Revie15 daysWed 2/5/20Tue 2/25/2025Task 7.3 C ‐ Bid Ready Documents15 daysWed 2/26/20Tue 3/17/2026GRANT FUNDING AGREEMENT PHASE517 days?Mon 9/2/19Tue 8/24/2127Financial Assistance Application32 daysMon 9/2/19Tue 10/15/1928Ecology Review and Public Comment Process186 daysWed 10/16/19Wed 7/1/2029Agreement Development152 days?Thu 7/2/20Fri 1/29/2130Agreement Approval1 day?Fri 1/29/21Fri 1/29/2131CONSTRUCTION PHASE147 days?Mon 2/1/21Tue 8/24/2132Construction Quality Assurance Plan15 daysMon 2/1/21Fri 2/19/2133Facility Operation and Maintenance Manual15 daysMon 2/1/21Fri 2/19/2134Ecology Review and Approv15 daysMon 2/22/21Fri 3/12/2135City Council Authorizes BidAdvertisement10 daysMon 3/15/21Fri 3/26/2136Bidding Period15 daysMon 3/29/21Fri 4/16/2137Notice of Award10 daysMon 4/19/21Fri 4/30/2138Construction Contract Execution15 daysMon 5/3/21Fri 5/21/2139Constuction Notice To Proceed1 dayMon 5/24/21Mon 5/24/2140Contractor Submittals15 daysTue 5/25/21Mon 6/14/2141Contractor Mobilization10 daysTue 6/15/21Mon 6/28/2142Pond Water Quality Improvements 30 daysTue 6/29/21Mon 8/9/2143Non Grant‐Funded Pipe Improvements15 daysTue 6/29/21Mon 7/19/2144Construction Punch List and Approval10 daysTue 8/10/21Mon 8/23/2145End of Construction Phase1 day?Tue 8/24/21Tue 8/24/21JanFebMarAprMayJunJulAugSepOctNovDecJanFebMarAprMayJunJulAugSepOctNovDecJanFebMarAprMayJunJulAug1st Quarter2nd Quarter3rd Quarter4th Quarter1st Quarter2nd Quarter3rd Quarter4th Quarter1st Quarter2nd Quarter3rd QuarterTaskSplitMilestoneSummaryProject SummaryInactive TaskInactive MilestoneInactive SummaryManual TaskDuration-onlyManual Summary RollupManual SummaryStart-onlyFinish-onlyExternal TasksExternal MilestoneDeadlineProgressManual ProgressCity of RentonHeather DownsProject Schedule (Updated 6-6-19)Page 1Project: Project Schedule_UpdaDate: Thu 10/3/19 APPENDIX A GEOTECHNICAL REPORT This page left intentionally blank. GEOTECHNICAL ENGINEERING REPORT Heather Downs Detention Pond Water Quality Retrofit, Renton Washington HWA Project No. 2018-139-21 Prepared for Louis Berger Inc. & City of Renton October 1, 2019 Geotechnical Engineering Pavement Engineering Geoenvironmental Hydrogeology Inspection & Testing TABLE OF CONTENTS 1.0 INTRODUCTION ....................................................................................................1 1.1 GENERAL .......................................................................................................1 1.2 PROJECT UNDERSTANDING ............................................................................1 2.0 FIELD INVESTIGATIONS .....................................................................................1 2.1 SUBSURFACE INVESTIGATION ........................................................................1 2.2 LABORATORY TESTING ..................................................................................2 3.0 SITE CONDITIONS ................................................................................................3 3.1 SITE DESCRIPTION .........................................................................................3 3.2 GENERAL GEOLOGY ......................................................................................3 3.3 SUBSURFACE SOIL CONDITIONS ....................................................................4 3.4 GROUND WATER ...........................................................................................4 4.0 CONCLUSIONS AND RECOMMENDATIONS ...................................................4 4.1 GENERAL .......................................................................................................4 4.2 SEISMIC DESIGN CONSIDERATIONS ................................................................5 4.2.1 Seismic Design ..............................................................................5 4.2.2 Soil Liquefaction ...........................................................................6 4.3 SLOPE STABILITY ...........................................................................................6 4.3.1 Static Loading Condition ...............................................................6 4.3.2 Pseudo-Static Stability...................................................................6 4.3.3 Slope Stability Considerations ......................................................7 4.4 INFILTRATION RECOMMENDATIONS ...............................................................7 4.5 EARTHWORK .................................................................................................8 4.5.1 Structural Fill and Compaction .....................................................8 4.5.2 Temporary Excavations .................................................................8 4.5.3 Wet Weather Earthwork ................................................................9 5.0 LIMITATIONS .........................................................................................................9 REFERENCES .........................................................................................................10 2018-139-21 Report 10-1-19 ii HWA GEOSCIENCES INC LIST OF FIGURES (FOLLOWING TEXT) Figure 1 Vicinity Map Figure 2 Site and Exploration Plan Figure 3 through Figure 5 Slope Stability Analyses Figure 6 BH-2 Water Elevation Data APPENDICES Appendix A: Field Exploration Figure A-1 Legend of Terms and Symbols Used on Exploration Logs Figures A-2 and A-3 Logs of Boreholes BH-1 and BH-2 Appendix B: Laboratory Test Results Figures B-1 through B-3 Particle Size Analysis of Soils GEOTECHNICAL ENGINEERING REPORT HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT RENTON, WASHINGTON 1.0 INTRODUCTION 1.1 GENERAL This report presents the results of geotechnical engineering studies for the Heather Downs Detention Pond Water Quality Retrofit project in Renton, Washington. This report includes the results of our field explorations and our geotechnical engineering analysis and recommendations completed to date for design and construction of proposed improvements. The approximate location of the project site is shown on the Vicinity Map, Figure 1, and on the Site Exploration Plan, Figure 2. 1.2 PROJECT UNDERSTANDING It is our understanding that the City of Renton proposes to retrofit the Heather Downs detention pond and improve its stormwater treatment performance. Improvements will include retrofitting the existing backup detention pond by creating a combined wetpond/ detention pond. This includes excavating wetpond cells ranging from 3 to 6 feet below the existing pond bottom. Additionally, improvements include intercepting stormwater along the northwest corner of the pond with a new catch basin and associated piping and potential modifications to the pond outlet control and overflow structure. Design of these improvements will require evaluation of the subsurface soil conditions and geotechnical recommendations. 2.0 FIELD INVESTIGATIONS 2.1 SUBSURFACE INVESTIGATION HWA GeoSciences Inc. (HWA) conducted two (2) geotechnical borings in support of the design of the Heather Downs Detention Pond Project. The locations of the boreholes are shown on the Site Exploration Plan, Figure 2. The borings, designated BH-1 and BH-2, were drilled to depths of 13 and 18 feet below ground surface (bgs), respectively. Both borings encountered auger refusal at these depths. The borings were drilled by Geologic Drill Partners, of Bellevue, Washington, on February 27, 2019 using a limited access Bobcat MT52 mounted track rig equipped with hollow stem augers. In each of the borings, Standard Penetration Test (SPT) sampling was performed using a 2-inch outside diameter split-spoon sampler driven by a 140-pound hammer raised using a rope and October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 2 HWA GEOSCIENCES INC. cathead. During the SPT, samples were obtained by driving the sampler 18 inches into the soil with the hammer free-falling 30 inches. The numbers of blows required for each 6 inches of penetration were 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; both indicators of soil strength. A 2-inch diameter monitoring well was installed in boring BH-2 to a depth of 18 feet. The slotted screen portion of the well was located from 5 to 15 feet bgs. An electronic data logger transducer was installed in the well and set to record ground water level every 5 minutes from February 27 to May 13, 2019. A geotechnical engineer from HWA logged each exploration and recorded all pertinent information. Soil samples obtained from the boreholes were classified in the field and representative portions were sealed in plastic bags. Pertinent information including soil sample depths, stratigraphy, soil engineering characteristics, and ground water occurrence was recorded. These soil samples were then taken to our Bothell, Washington, laboratory for further examination and testing. The stratigraphic contacts shown on the individual exploration logs represent the approximate boundaries between soil types; actual transitions may be more gradual. The soil and ground water conditions depicted are only for the specific date and locations reported and, therefore, are not necessarily representative of other locations and times. A legend of the terms and symbols used on the exploration logs is presented in Figure A-1. Summary logs of the borehole explorations are presented in Figures A-2 and A-3. 2.2 LABORATORY TESTING Representative soil samples obtained from the subsurface explorations were taken to the HWA laboratory for further examination and testing. Laboratory tests, as described below, were conducted on selected soil samples to characterize relevant engineering properties of the on-site soils. The tests included visual classifications, natural moisture contents, and grain size distributions. The tests were conducted in general accordance with appropriate American Society of Testing and Materials (ASTM) standards, as described below. The test results are also presented in Appendix B, and/or displayed on the exploration logs in Appendix A, as appropriate. Moisture Content of Soil: The moisture content of selected soil samples (percent by dry mass) was determined in accordance with ASTM D 2216. The results generally showed a moisture content from 6 to 20 %. The results are shown on the logs in Appendix A. Particle Size Analysis of Soils: Selected samples were tested to determine the particle size distribution of material in accordance with ASTM D422 (wet sieve or wet/hydrometer method). The results of the tests indicate that the soils at the project site are classified as SM, silty sand, October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 3 HWA GEOSCIENCES INC. according to ASTM soil classification. This corresponds to a NRCS hydraulic soil group A/D due to the presence of a relatively shallow perched water table. A summary of the general physical soil characteristics can be found in Section 3.3 Subsurface Soil Conditions. The results are summarized on the attached Appendix B, which also provide information regarding the classification of the samples and the moisture content at the time of testing. 3.0 SITE CONDITIONS 3.1 SITE DESCRIPTION The project site is shown on the Vicinity Map (Figure 1). The project site is located on the northeast corner of the intersection of Union Avenue SE and SE 4th Street. The detention pond is currently 5-6 feet deep with an access ramp at the gate on Union Avenue S. The site is adjacent to two residential lots. 3.2 GENERAL GEOLOGY The site is in the central portion of the Puget Sound Lowland, an elongated topographic and structural depression bordered by the Cascade Mountains on the east and the Olympic Mountains on the west. The Lowland is characterized by low-rolling relief with some deeply cut ravines. In general, the ground surface elevation is within 500 feet of sea level. The Puget Lowland was filled to significant depths by glacial and non-glacial sediments during the Pleistocene Epoch, although bedrock does outcrop in scattered locations throughout the area. Generally, the rock is deeply buried by Pleistocene and recent sediments. Geologists have generally agreed that the Puget Sound area was subjected to four or more major glaciations during the Pleistocene Epoch. Ice for these glacial events originated in the Coastal Mountains and the Vancouver Range of British Columbia. The maximum southward advance of ice was about halfway between Olympia and Centralia. The Pleistocene stratigraphic record in the central portion of the Puget Lowland is a complex sequence of glacially-derived and interglacial sediments. Erosion of certain deposits, as well as local deposition of sediments, further complicate the geologic setting. Review of Geologic Map of the Renton Quadrangle, King County, Washington (Mullineaux, 1965) indicates the local area is underlain by outwash along Cedar River valley, described as interbedded sand and pebble gravel. Advance outwash deposits generally consist of well-sorted sand and gravel deposited by streams issuing from advancing ice sheets. These deposits have been glacially overridden and are typically dense to very dense. October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 4 HWA GEOSCIENCES INC. 3.3 SUBSURFACE SOIL CONDITIONS The soils encountered in our explorations consist of near surface fill soils over native, glacial outwash deposits. Further descriptions of soils encountered in our explorations are presented below in order of deposition, beginning with the most recently deposited. The exploration logs in Appendix A provide more detailed description of subsurface conditions observed at specific locations and depths. Fill/ Disturbed Native: A layer of fill was encountered in boring BH-2 from ground surface to approximately 2.5 feet bgs. The fill consisted of medium dense, silty sand. The fill was likely placed during past construction operations in the area. Advance Outwash: Glacial advance outwash sediments were encountered in both borings. Both borings met refusal and were terminated in this deposit. The outwash typically consisted of dense to very dense, gravelly, slightly silty to silty, sand. The upper 4 to 8 feet of the outwash deposit was weathered and slightly less dense. 3.4 GROUND WATER Perched ground water was observed in both borings. Boring BH-1 (Elevation 369 feet) encountered ground water seepage from 4-6 feet bgs (approximate Elevation 363 to 365 feet). Boring BH-2 (Elevation 375 feet) encountered ground water seepage from 8-10 feet bgs (Elevation 365 to 366 feet). Ground water was observed to be perched over the very dense advance outwash layer. Shallow standing (ponded) water was observed in the detention pond at the time of drilling, likely a result of recent snow/rain. A monitoring well with electronic data logger transducers was installed in boring BH-2 and set to record water level every 5 minutes. A plot of the ground water level measured in this well, from February 27 to May 13, 2019, is shown in Figure 6. The ground water level was observed to vary between approximately 7.8 and 13.3 feet bgs (approximate Elevation 361.7 to 367.2 feet). We expect the ground water levels across the site to vary seasonally in response to precipitation. 4.0 CONCLUSIONS AND RECOMMENDATIONS 4.1 GENERAL Below the topsoil/fill at the site, the native subgrade soils consist of dense to very dense advance outwash (silty to slightly silty sand with gravel). Given the measured high ground water level (approximate Elevation 367 feet) there is not sufficient separation between the October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 5 HWA GEOSCIENCES INC. bottom of pond and ground water level to utilize infiltration. Additionally, a pond liner will be required to maintain the minimum design water level required. The existing pond side slopes stand at about 1H:1V with a height of about 5 feet. Slope stability analyses (described in Section 4.3) indicate a seismic factor of safety of less than 1.0 for deepening the pond at the current slope. Slopes of 2H:1V will be required to deepen the pond below the existing 1H:1V slope. The following sections provide geotechnical recommendations for slope stability, infiltration and earthwork considerations. 4.2 SEISMIC DESIGN CONSIDERATIONS 4.2.1 Seismic Design We understand the structures at the project site are being designed in accordance with the 2015 International Building Code (IBC), (ICC, 2011, 2014). The IBC requires above-grade structures be designed for earthquake loads consisting of the inertial forces induced by a “Maximum Considered Earthquake” (MCE), which corresponds to an earthquake with a 2% probability of exceedance (PE) in 50 years (approximately 2,475-year return period). Accordingly, the relevant probabilistic spectral response parameters were developed using the United States Geological Survey, and Structural Engineers Association of California (SEAOC) and Office of Statewide Health Planning and Development (OSHPD)’s website. The IBC accounts for the effects of site-specific subsurface ground conditions on the response of structures in terms of site classes. Site classes are defined by the average density and stiffness of the soil profile underlying the site. The Site Class can be correlated to the average standard penetration resistance (NSPT) in the upper 100 feet of the soil profile. Based on our characterization of the subsurface conditions, the subject site classifies as IBC Site Class D. Table 1 presents the design spectral seismic coefficients obtained for this site based on risk category I/II/III. Based on the SDS and SD1 values, the site is considered as Seismic Design Category D. Table 1. Design Seismic Coefficients for 2015 IBC Code Based Evaluation Site Class Spectral Acceleration at 0.2 sec. SS, g Spectral Acceleration at 1.0 sec S1, g Design Spectral Acceleration at 0.2 sec. SDS, g Design Spectral Acceleration at 1.0 sec. SD1, g Site Coefficients Peak Horizontal Acceleration PGA, (g) Fa Fv D 1.397 0.523 0.931 0.523 1.00 1.5 0.372 October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 6 HWA GEOSCIENCES INC. 4.2.2 Soil Liquefaction Soil liquefaction is a phenomenon where loose, saturated, granular deposits temporarily lose strength and behave as a liquid in response to moderate to strong earthquake shaking. Primary factors controlling the development of liquefaction include the intensity and duration of strong ground motions, the characteristics of subsurface soils, in-situ stress conditions and the depth to ground water. The native soils at the project site primarily consist of dense to very dense outwash sands. Given the density of these soils, liquefaction is unlikely. 4.3 SLOPE STABILITY HWA performed global slope stability analyses along the slopes of the detention pond assuming the current site geometry and an additional excavation depth of 6 feet. Global slope stability was analyzed under two loading scenarios: static loading and pseudo-static earthquake loading. Soil strength parameters and ground water conditions for these analyses were assumed based on field exploration observations and laboratory test results. Limit equilibrium analyses were performed using the computer program SLIDE 2018. Global factors of safety with respect to potential deep-seated failure surfaces were determined under the two load cases. The factor of safety computed is the ratio of the summation of the driving forces to the summation of the resisting forces. Where the factor of safety is less than 1.0, instability is predicted. For global slope stability design, minimum acceptable factors of safety under static loading conditions are commonly taken as 1.5 for slopes supporting structures or walls. For slopes adjacent to structures or minor walls where slope instability would have a lesser effect in terms of safety considerations, the factor of safety may be taken as 1.3. Minimum acceptable factor of safety for the pseudo-static case is 1.1. 4.3.1 Static Loading Condition If the current 1H:1V slope was extended for the pond deepening, the side slopes were found to be stable under static loading condition with factor of safety slightly less than 1.3, as shown in Figure 3. This factor of safety shows stability under static loading but is less than the minimum required. 4.3.2 Pseudo-Static Stability Seismic stability of the existing slope was evaluated using a pseudo-static horizontal acceleration of 0.186g, which is ½ of the peak ground acceleration (PGA) associated with the 1:1033-year design earthquake for this site location. From our analyses, we conclude that, under a design earthquake, a factor of safety for global stability less than 1 will exist for deepening the pond at 1H:1V, as shown in Figure 4. Therefore, slope instability is expected to occur as a result of the design earthquake. We October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 7 HWA GEOSCIENCES INC. expect that slope instability will manifest as a rotational failure of the sides which could cause damage to the adjacent residential properties. Additional analyses conclude that the pond deepening excavation will need to be sloped at a 2H:1V slope to maintain stability in the pseudo- static scenario. With this slope, we conclude that, under a design earthquake, a factor of safety for global stability above 1.1 will exist, as shown in Figure 5. 4.3.3 Slope Stability Considerations Our slope stability analyses indicate that deepening the pond 6 feet at a 1H:1V side slope is marginally stable under static loading conditions, but with a factor of safety less than desired. During the design earthquake the side slopes are expected to become unstable and undergo rotational slope failure, potentially impacting the nearby residences. To achieve adequate factors of safety, both static and seismic, side slopes for pond deepening excavations should be 2H:1V or flatter. We recommend that excavations occur during dry summer months when ground water levels are at their lowest. Several existing tree stumps and their roots exist around the top edge of the pond. We recommend that during construction these stumps are not removed. Removal may cause disturbances to the current slope stability. However, it should be noted that the tree stumps and roots will decay over time. This can cause the potential for ground subsidence which may likely require future maintenance. 4.4 INFILTRATION RECOMMENDATIONS It is our understanding that the design team would like to evaluate the feasibility of utilizing the detention pond to infiltrate stormwater. Use of onsite stormwater infiltration for design will be very limited due to the presence of relatively impermeable materials observed within 4 to 6 feet bgs in both borings. Ground water was observed to be perched in the weathered zone above the very dense advance outwash layer. Transducer readings in boring BH-2 indicated that the ground water level fluctuated between about 8 and 13.5 feet bgs from February 27 to May 13, 2019 (about 3 to 8.5 feet below the existing bottom of pond). It is our understanding that a 3 to 6 feet deep excavation below the existing pond bottom is proposed for the wetpond cell(s). At these depths, and given the observed high ground water levels, sufficient separation will not be available to utilize onsite infiltration at this site. Additionally, if the pond is deepened by 3 to 6 feet, excavation will likely intercept the local perched water level. This may result in standing (ponded) water at the new pond bottom during wet periods of the year but will not affect the local ground water level. We understand that the current pond outlet elevation will remain the same. October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 8 HWA GEOSCIENCES INC. It is our understanding that the water level in the pond must not drop more than 12 inches in any measurement period. As shown in Figure 6, the measured ground water level varied between a depth of over 5 feet during the time period from February 27 to May 13, 209. As a result, a pond liner will be required to maintain the water level in the pond. 4.5 EARTHWORK 4.5.1 Structural Fill and Compaction The native soils are expected to be moisture sensitive and contain high fines component (about 22 to 34% based on grain size analyses). We do not recommend the use of on-site materials as structural fill however, they could be suitable for limited re-use on site during the dry summer months. Native excavated material may be used to modify the access road. If structural fill is to be placed, we recommend that imported material, as described below, be used. Imported structural fill should consist of clean, non-plastic, free-draining sand and gravel free from organic matter or other deleterious materials. Such materials (Gravel Borrow) should contain particles of less than 4 inches maximum dimension, with less than 7% fines (based on the ¾-inch fraction) as described in Section 9-03.14(1), Gravel Borrow, of the WSDOT Standard Specifications (WSDOT, 2018). Structural fill should be placed in loose, horizontal, lifts of not more than 8 inches in thickness and compacted to at least 95% of the maximum dry density, as determined using test method ASTM D 1557 (modified Proctor). At the time of placement, the moisture content of structural fill should be at or near optimum. The procedure required to achieve the specified minimum relative compaction depends on the size and type of compaction equipment, the number of passes, thickness of the layer being compacted, and the soil moisture-density properties. Generally, loosely compacted soils are a result of poor construction technique or improper moisture content. Soils with a high percentage of silt or clay are particularly susceptible to becoming too wet, and coarse-grained materials easily become too dry, for proper compaction. Silty or clayey soils with a moisture content too high for adequate compaction should be dried as necessary, or moisture conditioned by mixing with drier materials, or other methods. For coarse- grained structural fill soils, moisture conditioning by sprinkling before and during compaction is sometimes required to achieve the required relative compaction. 4.5.2 Temporary Excavations Any excavations deeper than 4 feet should be sloped or shored in accordance with current State of Washington Labor and Industries Safety and Health guidelines. Per these guidelines, all site soils are classified as Type C Soil. Temporary unsupported excavations within Type C Soil should be sloped no steeper than 1.5H:1V. Flatter side slopes could be required for excavations below the water table or where ground water seepage is present. October 1, 2019 HWA Project No. 2018-139-21 2018-139-21 Report 10-1-19 9 HWA GEOSCIENCES INC. The contractor should monitor the stability of the temporary excavations and adjust the construction schedule and slope inclination accordingly. The contractor should be responsible for control of ground and surface water and should employ sloping, slope protection, ditching, sumps, dewatering, and other measures, as necessary, to prevent sloughing of soils and heave of the bottom of the excavation. 4.5.3 Wet Weather Earthwork As the native, on-site silty soils are highly moisture sensitive and will be unworkable when wet, we do not recommend earthwork be performed in wet conditions. General recommendations relative to earthwork that must necessarily be performed during wet weather or in wet conditions are presented below. These recommendations should be incorporated into the contract specifications. • Earthwork should be performed in small areas to minimize exposure to wet weather. Excavation or the removal of unsuitable soils should be followed promptly by the placement and compaction of clean structural fill. The size and type of construction equipment used may have to be limited to prevent soil disturbance. • The ground surface within the construction area should be graded to promote run-off of surface water and to prevent the ponding of water. • The ground surface within the construction area should be sealed by a smooth drum vibratory roller, or equivalent, and under no circumstances should be left uncompacted and exposed to moisture. • Excavation and placement of structural fill material should be performed under the full- time observation of a representative of the geotechnical engineer, to determine that the work is being accomplished in accordance with the project specifications and the recommendations contained herein. 5.0 LIMITATIONS We have prepared this report for Berger Louis Inc. and the City of Renton for use in design of a portion of this project. This report should be provided in its entirety to prospective contractors for bidding and estimating purposes; however, the conclusions and interpretations presented herein should not be construed as a warranty of the subsurface conditions. Experience shows that soil and ground water conditions can vary significantly over small distances. Inconsistent conditions may occur between explorations that 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 to review the recommendations made in this REFERENCES AASHTO, 2017, LRFD Bridge Design Specification, 8th Edition, November 2017. American Association of State Highway and Transportation Officials, 1993, AASHTO Guide for Design of Pavement Structures, American Association of State Highway and Transportation Officials. American Association of State Highway and Transportation Officials (AASHTO), 2011, Guide Specifications for LRFD Seismic Bridge Design, 2nd Edition, Washington D.C. American Association of State Highway and Transportation Officials (AASHTO), 2011, Guide Specifications for LRFD Seismic Bridge Design, 2nd Edition, with 2012, 2014 and 2015 Interim Revisions, Washington D.C. International Code Council (ICC), 2015, International Building Code (IBC), Country Club Hills, Illinois. Mullineaux, 1965, Geologic map of the Renton quadrangle, King County, Washington, USGS, Geologic Quadrangle Map GQ-405, Scale: 1:24,000. SEAOC and OSHPD, Seismic Design Maps, https://seismicmaps.org/ USGS, 2019, Design Ground Motions, Earthquake Hazards Program, https://earthquake.usgs.gov/hazards/designmaps/index.php Washington State Department of Ecology, 2014, Stormwater Management Manual for Western Washington, as Amended in December 2014. WSDOT, 2015, Geotechnical Design Manual, Washington State Department of Transportation. WSDOT, 2018, Standard Specifications for Road, Bridge, and Municipal Construction, M 41-10. VICINITY MAP HEATHER DOWNS DENTENTION POND RENTON, WA 1 2018-139-21 FIGURE NO. PROJECT NO. MAP NOT TO SCALE BASE MAP FROM GOOGLE MAPS DATA © 2018 GOOGLE © 2016 Microsoft MDA Geospatial Services Inc. Approximate Project Site N © 2019 Microsoft Corporation © 2019 DigitalGlobe ©CNES (2019) Distribution Airbus DS SITE &EXPLORATION PLAN2FIGURE NO.PROJECT NO.2018-139-21DRAWN BY BFMCHECK BY SKDATE03.13.2019HEATHER DOWNS DETENTION PONDRENTON, WASHINGTONS:\2018 PROJECTS\2018-139-21 HEATHER DOWNS DETENTION POND\CAD\2018-139-21 HEATHER DOWNS DETENTION POND.DWG <Fig 2> Plotted: 3/13/2019 11:28 AM06121824SCALE: 1" = 12'HEATHER DOWNS DETENTION PONDScale: 1" = 12'-0"PONDUNION AVE SEEXPLORATION LEGENDBH-1Borehole Designation and Approximate Location (HWA GEOSCIENCES, INC., 2019)SE 4TH STREET BH-1BH-2 This page left intentionally blank. FIGURE NO. PROJECT NO. SLOPE STABILITY ANALYSIS USING SLIDE 1H:1V SLOPED EXCAVATION -STATIC CONDITION HEATHER DOWNS DETENTION POND RENTON, WASHINGTON 3 2018-139-21 Proposed Excavation at 1H:1V Slope Existing 1H:1V Slope Static Loading Condition Bishop Simplified Method FS=1.245 Required Factor of Safety = 1.3 This page left intentionally blank. FIGURE NO. PROJECT NO. SLOPE STABILITY ANALYSIS USING SLIDE 1H:1V SLOPED EXCAVATION – PSEUDO STATIC CONDITION HEATHER DOWNS DETENTION POND RENTON, WASHINGTON 4 2018-139-21 Pseudo- Static Condition Design PGA= 0.0.372 Kh= PGA/2 Bishop Simplified Method FS=0.856 Required Factor of Safety = 1.1 Proposed Excavation at 1H:1V Slope Existing 1H:1V Slope This page left intentionally blank. FIGURE NO. PROJECT NO. SLOPE STABILITY ANALYSIS USING SLIDE 2H:1V SLOPED EXCAVATION –PSEUDO STATIC CONDITION HEATHER DOWNS DETENTION POND RENTON, WASHINGTON 5 2018-139-21 Pseudo- Static Condition Design PGA= 0.372 Kh= PGA/2 Bishop Simplified Method FS=1.149 Required Factor of Safety = 1.1 Proposed Excavation at 2H:1V Slope Existing 1H:1V Slope This page left intentionally blank. 361 362 363 364 365 366 367 368 Ground Water Elevation (ft)Date and Time Water Elevation from February 27, 2019 to May 13, 2019 Ground Surface Elevation: 375 ft BH-2 WATER ELEVATION DATA 6 2018-139-21 FIGURE NO. PROJECT NO.HEATHER DOWNS DETENTION POND RENTON, WASHINGTON Proposed Pond Bottom This page left intentionally blank. APPENDIX A FIELD EXPLORATION This page left intentionally blank. A-1 SYMBOLS USED ON EXPLORATION LOGS LEGEND OF TERMS AND to 30 over 30 Approximate Undrained Shear Strength (psf) <250 250 - No. 4 Sieve Sand with Fines (appreciable amount of fines) amount of fines) More than 50% Retained on No. 200 Sieve Size Sand and Sandy Soils Clean Gravel (little or no fines) More than 50% of Coarse Fraction Retained on No. 4 Sieve Gravel with SM SC ML MH CH OH RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE Very Loose Loose Medium Dense Very Dense Dense N (blows/ft) 0 to 4 4 to 10 10 to 30 30 to 50 over 50 Approximate Relative Density(%) 0 - 15 15 - 35 35 - 65 65 - 85 85 - 100 COHESIVE SOILS Consistency Very Soft Soft Medium Stiff Stiff Very Stiff Hard N (blows/ft) 0 to 2 2 to 4 4 to 8 8 to 15 15 Clean Sand (little or no fines) 50% or More of Coarse Fraction Passing Fine Grained Soils Silt and Clay Liquid Limit Less than 50% 50% or More Passing No. 200 Sieve Size Silt and Clay Liquid Limit 50% or More 500 500 - 1000 1000 - 2000 2000 - 4000 >4000 DensityDensity USCS SOIL CLASSIFICATION SYSTEM Coarse Grained Soils Gravel and Gravelly Soils Highly Organic Soils GROUP DESCRIPTIONS Well-graded GRAVEL Poorly-graded GRAVEL Silty GRAVEL Clayey GRAVEL Well-graded SAND Poorly-graded SAND Silty SAND Clayey SAND SILT Lean CLAY Organic SILT/Organic CLAY Elastic SILT Fat CLAY Organic SILT/Organic CLAY PEAT MAJOR DIVISIONS GW SP CL OL PT GP GM GC SW COHESIONLESS SOILS Fines (appreciable LEGEND 00000.GPJ 2/27/15 FIGURE: Coarse sand Medium sand SIZE RANGE Larger than 12 in Smaller than No. 200 (0.074mm) Gravel time of drilling) Groundwater Level (measured in well or AL CBR CN Atterberg Limits:LL = Liquid Limit California Bearing Ratio Consolidation Resilient Modulus Photoionization Device Reading Pocket Penetrometer Specific Gravity Triaxial Compression Torvane 3 in to 12 in 3 in to No 4 (4.5mm) No. 4 (4.5 mm) to No. 200 (0.074 mm) COMPONENT DRY Absence of moisture, dusty, dry to the touch. MOIST Damp but no visible water. WET Visible free water, usually soil is below water table. Boulders Cobbles Coarse gravel Fine gravel Sand MOISTURE CONTENT COMPONENT PROPORTIONS Fine sand Silt and Clay 5 - 12% PROPORTION RANGE DESCRIPTIVE TERMS Clean Slightly (Clayey, Silty, Sandy) 30 - 50% Components are arranged in order of increasing quantities. Very (Clayey, Silty, Sandy, Gravelly) 12 - 30%Clayey, Silty, Sandy, Gravelly open hole after water level stabilized) Groundwater Level (measured at 3 in to 3/4 in 3/4 in to No 4 (4.5mm) No. 4 (4.5 mm) to No. 10 (2.0 mm) No. 10 (2.0 mm) to No. 40 (0.42 mm) No. 40 (0.42 mm) to No. 200 (0.074 mm) PL = Plastic Limit DD DS GS K MD MR PID PP SG TC TV Dry Density (pcf) Direct Shear Grain Size Distribution Permeability Approx. Shear Strength (tsf) Percent Fines%F Moisture/Density Relationship (Proctor) Approx. Compressive Strength (tsf) Unconfined CompressionUC (140 lb. hammer with 30 in. drop) Shelby Tube Small Bag Sample Large Bag (Bulk) Sample Core Run Non-standard Penetration Test 2.0" OD Split Spoon (SPT) NOTES: Soil classifications presented on exploration logs are based on visual and laboratory observation. Density/consistency, color, modifier (if any) GROUP NAME, additions to group name (if any), moisture content. Proportion, gradation, and angularity of constituents, additional comments. (GEOLOGIC INTERPRETATION) Please refer to the discussion in the report text as well as the exploration logs for a more complete description of subsurface conditions. Soil descriptions are presented in the following general order: < 5% 3-1/4" OD Split Spoon with Brass Rings (3.0" OD split spoon) TEST SYMBOLS SAMPLE TYPE SYMBOLS GROUNDWATER SYMBOLS COMPONENT DEFINITIONS Heather Downs Detention Pond Renton, Washington PROJECT NO.:2018-139-21 S-1 S-2 S-3 S-4 S-5 GS GSHYD GS GS SM SM SM SP SM 13-20-23 8-24-50/4" 35-50/5" 34- 50/5" 19-39-50/5.5" Medium dense, olive brown, silty, SAND, moist. (WEATHERED ADVANCE OUTWASH) Dense, olive brown, to olive gray, gravelly, very silty, SAND. moist to wet. Abundant dark brown organics and root debris. Grades to silty sand. (ADVANCE OUTWASH) Very dense, olive brown, to light yellow brown, gravelly, silty, fine to coarse SAND, wet. Very dense, olive gray, silty, gravelly, fine to medium SAND, moist. 1" layer of rust mottling. Very dense, olive gray, silty, gravelly, fine to medium SAND, moist. Gravel is sub-angular to rounded. Very dense, olive gray grades to gray, slighlty silty, fine SAND, moist. Boring encountered refusal at 13 feet below ground surface bgs. Boring was moved 3 feet east and encountered refusal at 11.5 feet bgs. Boring abandoned with hydrated bentonite chips. Perched ground water seepage observed from 4-6 feet bgs. 0 20 40 60 80 100 Water Content (%) Plastic Limit (140 lb. weight, 30" drop) Blows per foot (blows/6 inches)USCS SOIL CLASSDESCRIPTION SAMPLE TYPESAMPLE NUMBERPEN. RESISTANCEOTHER TESTSGROUNDWATERStandard Penetration Test A-2SYMBOL0 10 20 30 40 50 Liquid Limit BORING: BH-1 PAGE: 1 of 1 Water Content (%) Natural Water ContentNOTE: This log of subsurface conditions applies only at the specified location and on the date indicatedand therefore may not necessarily be indicative of other times and/or locations. PZO-DSM 2018-139-21.GPJ 3/14/19 FIGURE:PROJECT NO.:2018-139-21 Renton, Washington Heather Downs Detention PondDEPTH(feet)0 5 10 15 20 ELEVATION(feet)DRILLING COMPANY: Geologic Drill Partners, Inc. DRILLING METHOD: HSA, Mini Bobcat Drill Rig LOCATION: See Figure 2 SAMPLING METHOD: SPT w/ cathead DATE STARTED: 2/27/2019 DATE COMPLETED: 2/27/2019 LOGGED BY: S Khandaker SURFACE ELEVATION: 369 Feet >> >> >> >> S-1 S-2 S-3 S-4 S-5 S-6a S-6b S-7 GS GS GS SM SM SM SP 19-19-36 10-15-16 12-16-19 17-16-32 42-50/3" 19-22-25 50/0" Medium dense, dark brown, silty, fine to medium sand, moist. (TOPSOIL/ FILL) (WEATHERED ADVANCE OUTWASH) Very dense, dark brown grades to olive brown, silty, gravelly, fine to medium SAND, moist. Abundant organics and root debris. Heavily rust mottled at toe. Dense, olive gray, rounded gravelly, silty, fine to medium SAND, mist. Scattered coarse sand. 1/4" medium sand lense observed. Dense, olive gray, gravelly, silty, fine to medium SAND, wet. Dense, olive gray to olive brown, rounded gravelly, silty, fine to medium SAND, moist. Sample grades finer with depth. (ADVANCE OUTWASH) Very dense, olive gray, very gravelly, silty, fine to coarse SAND, moist. Minor rust mottling at toe, gravel grades finer than above. Dense, olive brown to olive gray, gravelly, silty SAND, moist. Dense, olive brown, gravelly, clean, medium SAND, moist. Black sand at contact. No recovery. Boring encountered refusal at 18 feet below ground surface bgs. Perched ground water seepage observed from 8-10 feet bgs at time of drilling. Highest recorded ground water at 7.8 feet bgs on May 13 3019. Well ID: BKU 673 0 20 40 60 80 100 Water Content (%) Plastic Limit (140 lb. weight, 30" drop) Blows per foot (blows/6 inches)USCS SOIL CLASSDESCRIPTION SAMPLE TYPESAMPLE NUMBERPEN. RESISTANCEOTHER TESTSPIEZOMETERStandard Penetration Test A-3SYMBOLSCHEMATIC0 10 20 30 40 50 Liquid Limit BORING: BH-2 PAGE: 1 of 1 Water Content (%) Natural Water ContentNOTE: This log of subsurface conditions applies only at the specified location and on the date indicatedand therefore may not necessarily be indicative of other times and/or locations. PZO-DSM 2018-139-21.GPJ 5/21/19 FIGURE:PROJECT NO.:2018-139-21 Renton, Washington Heather Downs Detention PondDEPTH(feet)0 5 10 15 20 370 365 360ELEVATION(feet)DATE COMPLETED: 2/27/2019 DRILLING COMPANY: Geologic Drill Partners, Inc. DRILLING METHOD: HSA, Mini Bobcat Drill Rig LOCATION: See Figure 2 DATE STARTED: 2/27/2019 SAMPLING METHOD: SPT w/ cathead LOGGED BY: S. Khandaker >> >> >> SURFACE ELEVATION: 375.0 feet This page left intentionally blank. APPENDIX B LABORATORY TEST RESULTS This page left intentionally blank. 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-1 S-2 S-3 2.5 - 4.0 5.0 - 6.3 7.5 - 8.4 #10 47.6 58.5 52.7 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND B-1 Coarse #60#40#20 Fine Coarse SYMBOL Gravel% 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 18.4 16.9 21.4 Sand% (SM) Olive-brown, silty SAND with gravel (SM) Light olive-brown, silty SAND with gravel (SM) Dark gray, silty SAND with gravel Fines% 0.00050.005 CLAY BH-1 BH-1 BH-1 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 30 13 10 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D6913 33.9 24.6 25.9 2018-139-21PROJECT NO.: HWAGRSZ 2018-139-21.GPJ 03/11/19 FIGURE: Heather Downs Detention Pond Renton, Washington 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-4 S-2 S-3 10.0 - 10.9 5.0 - 6.5 7.5 - 9.0 #10 52.7 61.1 56.2 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND B-2 Coarse #60#40#20 Fine Coarse SYMBOL Gravel% 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 25.6 16.5 21.9 Sand% (SM) Olive brown, silty SAND with gravel (SM) Olive-brown, silty SAND with gravel (SM) Olive-brown, silty SAND with gravel Fines% 0.00050.005 CLAY BH-1 BH-2 BH-2 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 7 14 12 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D6913 21.7 22.4 21.8 2018-139-21PROJECT NO.: HWAGRSZ 2018-139-21.GPJ 03/11/19 FIGURE: Heather Downs Detention Pond Renton, Washington 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-4 10.0 - 11.5 #10 55.6 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND B-3 Coarse #60#40#20 Fine Coarse SYMBOL Gravel% 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 22.8 Sand% (SM) Olive-brown, silty SAND with gravel Fines% 0.00050.005 CLAY BH-2 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 12 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D6913 21.7 2018-139-21PROJECT NO.: HWAGRSZ 2018-139-21.GPJ 03/11/19 FIGURE: Heather Downs Detention Pond Renton, Washington APPENDIX B HYDROLOGIC AND HYDRAULIC MODELING This page left intentionally blank. This page left intentionally blank. Heather DownsDetention PondFernwoodDetention PondBASIN2BASIN3BASIN1410400390380350320300250360 3302803402902703703 6 0 3403303 0 0 2 8 0 2 5 0 3 2 0 290 270 35030030028041040041040039038 0370 3603504003 9 0 3503403703102403103502604104104004 1 0 41 0410 4 10 4104104104004004003903 90 3903803 8 0380 370370370370350350 310400 Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS UserCommunity0 300 600150Feet±Topography MapFigure X.XHeather DownsDetention PondLegendParcelsSubbasinsPipeSource: City of Renton GIS This page left intentionally blank. City of Renton Heather Downs Detention Pond Subject: Subbasin Pervious and Impervious Parameters Zoning ID/Land Use Description RMH Residential Manufactured Home Park Total Basin Area =28.90 Ac R-6(3)Residential-6 (3-6 DU/ac)Total Impervious Area =8.64 Ac R-10 Residential-10 Total Impervous % for whole bas =30% Notes: (1) (2)Impervious Area = Subbasin Area x Impervious Fraction x Effective Impervious Area. (3)Area generally has a average density of about 4 DU/ac. RMH R-6 R-10 0.25 0.46 0.58 0.50 0.66 0.80 Subbasin 1 0.154 3.084 0.408 3.65 1.145 31%2.116 0.387 Subbasin 2 0.000 5.460 0.000 5.46 1.658 30%3.213 0.557 0.032 Subbasin 3 0.950 18.843 0.000 19.79 5.839 30%3.292 1.961 0.009 5.721 2.914 0.058 C Lawn Steep Pervious Area Soil and Slop (Ac) A/B Lawn Flat A/B Lawn Mod % Impervious Area per Subbasin (ac)Impervious Fraction (1) Effective Impervious Fraction (1) Area (Acres)(2) Zoning Percentages have been adopted from theKing County Drainage Manual. Land uses were highly variable. An average value was used based on a high level review of areal mapping and engineering judgement. Effective Impervious Fraction is that portion of the impervious area assumed to be directly connected to the drainage system. Total Subbasin Area (Acres) A/B Lawn Steep C Lawn Flat C Lawn Mod City of Renton Heather Downs Water Quality Retrofit Project Subject: WWHM Model Schematic Date: 2-17-19 City of Renton Heather Downs WQ Retrofit Project Subject: Estimate of Existing Detention Pond Data Pond Name: Fernwood Pond Stage Storage ELEVATION STAGE TOP DIMENSIONS SURFACE INCREMENTAL CUMM. STORAGE COMMENTS(FEET)WIDTH LENGTH AREA STORAGE STORAGE (SF)(CF)(CF)(AC-CF) 388 0 N/A N/A 0 0 0 0.00 Area Measurement3891N/A N/A 840 420 420 0.01 Permiter ditch area: L=210', Top Width=4' 390 2 50 74 3,700 2270 2690 0.06 Pond Dimension Calculation 391 3 56 80 4,480 4090 6780 0.16 Pond Dimension Calculation. Overflow at 391 392 4 58 82 4,756 4618 11398 0.26 Pond Dimension Calculation POND DIMENSIONAL CHARACTERISTICS ABOVE EL. 390.0 BOTTOM DIMENSTIONS Configuration Width "X1" Ft.50 Length "Y1" Ft. 74 Side slope Ft/Ft 3 Pond Outlet Structure Outlet Dia.12" Riser Dia.12"Oulet Elev.387.81 Orifice #1 Elev.385.81 Dia.4 inchesOrifice #2 N/A Elev. Dia. Riser OF Elev.391 SDMH 2001RIM=374.53IE 12" CONC S=373.43IE 12" CMP NW=371.73IE 8" CONC W=370.68IE 12" CONC N=369.55IE 12" CONC E=369.43SDMH 2046RIM=374.48IE 15" CMP W=369.43IE 12" CMP N=368.13IE 24" CONC SE=368.0320012048SDMH 2048RIM=374.09IE 12" CMP SW=369.69IE 12" CMP S=368.49IE 12" CONC N=368.06IE 12" CONC E=367.79216524" CMPW/DEBRIS CAGEIE=368.222049SDMH 2049RIM=374.01IE 12" PVC NW=367.66IE 12" CONC E-W=367.58SDMH 2165RIM=375.31TOP 12" VERT CMP O/F SE=373.61 IE=368.01IE 8" PVC SW=371.61IE 24" CONC NW=368.01IE 24" CMP NE=368.0120472045SDCB 2045 TYPE IRIM=373.96IE 15" CMP E=370.3020032169SDCB 2047 TYPE IRIM=373.72IE 8" CMP NE=372.022002SDCB 2002 TYPE ISTRUCTURE ROTATIONRIM=373.47IE 12" CMP N=370.34IE 12" CMP NE=102200101201SDCB 2169 TYPE IRIM=373.64IE 12" CMP N=370.79CONC WALKCONC WALK SDMH 2003RIM=371.99ROOTS RAISINGCONC WALK2-8", 1-10", 2-12"CEDAR CLUSTER1-8", 2-6", 1-16"CEDAR CLUSTER"NO PARKINGHERE TO CORNER"24"1-12", 1-24"CEDARORANGEPAINTED CIRCLE12" STUMPGROUND=374.8'TOP=376.4' 8" STUMPGROUND=374.7'TOP=375.0'24" STUMPGROUND=375.7TOP=377.1'30" STUMPGROUND=376.9TOP=378.1'36" STUMPGROUND=377.4'TOP=379.4' 36" STUMPGROUND=376.5'TOP=377.7'WV LID=373.87'TOP NUT=372.77'WV LID=373.46'TOP NUT=370.76'WMH LID=373.96'TOP NUT=371.46'TOP PIPE TO N=369.46'DOUBLE 6' CLFSWING GATEDOUBLE 6' CLFSWING GATE 6' CLF"STOP"DOUBLE YELLOW LANE MARKERSYELLOW SKIP LANE MARKERS PONDDWY 370 370 375370 370376377375 374374374369 369 374 375374374374 374374 375373FL CURBTOP BACK CURBFND 5/8" REBAR,NO CAPSET 5/8" REBAR& CAP, "46878"FND 1/2" REBAR W/WHITECAP, "B&F INC 12870 &129XX" (ILLEGIBLE)FND 5/8" REBAR,NO CAP3692046 City of Renton Heather Downs WQ Retrofit Project Subject: Estimate of Existing Detention Pond Data Pond Name: Heather Downs Vertical Datum (NAVD 88) Pond Stage Storage ELEVATION STAGE TOP DIMENSIONS SURFACE INCREMENTAL CUMM. STORAGE COMMENTS (FEET)WIDTH LENGTH AREA STORAGE STORAGE (SF)(CF)(CF)(AC-CF) See Pond Hydraulics Table for Heather Downs Pond POND DIMENSIONAL CHARACTERISTICS ABOVE EL. 369.32 (bottom of live storage as modeled)BOTTOM DIMENSTIONS Configuration Width "X1" Ft.58 Length "Y1" Ft. 98 Side slope Ft/Ft 1 Pond Outlet Structure Outlet Dia.12" Riser Dia.12"Oulet Elev.368.1 Orifice #1 Elev.368.1 Dia.2.50 inches Orifice #2 Elev.371.2 Dia.2.75 inches Riser OF Elev.373.61 WWHM2012 PROJECT REPORT DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 2 General Model Information Project Name:Existing model_trap pond_new datum Site Name: Site Address: City: Report Date:4/16/2019 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2018/10/10 Version:4.2.16 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 2.116 A B, Lawn, Mod 0.387 Pervious Total 2.503 Impervious Land Use acre ROADS MOD 1.145 Impervious Total 1.145 Basin Total 3.648 Element Flows To: Surface Interflow Groundwater Heather Downs Pond Heather Downs Pond DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 4 Basin 2 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 3.213 A B, Lawn, Mod 0.557 A B, Lawn, Steep 0.032 Pervious Total 3.802 Impervious Land Use acre ROADS MOD 1.658 Impervious Total 1.658 Basin Total 5.46 Element Flows To: Surface Interflow Groundwater Fernwood Pond Fernwood Pond DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 5 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 3.292 A B, Lawn, Mod 1.961 A B, Lawn, Steep 0.009 C, Lawn, Flat 5.721 C, Lawn, Mod 2.914 C, Lawn, Steep 0.058 Pervious Total 13.955 Impervious Land Use acre ROADS MOD 5.839 Impervious Total 5.839 Basin Total 19.794 Element Flows To: Surface Interflow Groundwater Heather Downs Pond Heather Downs Pond DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 6 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 2.116 A B, Lawn, Mod 0.387 Pervious Total 2.503 Impervious Land Use acre ROADS MOD 1.145 Impervious Total 1.145 Basin Total 3.648 Element Flows To: Surface Interflow Groundwater Heather Downs Pond Heather Downs Pond DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 7 Basin 2 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 3.213 A B, Lawn, Mod 0.557 A B, Lawn, Steep 0.032 Pervious Total 3.802 Impervious Land Use acre ROADS MOD 1.658 Impervious Total 1.658 Basin Total 5.46 Element Flows To: Surface Interflow Groundwater Fernwood Pond Fernwood Pond DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 8 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 3.292 A B, Lawn, Mod 1.961 A B, Lawn, Steep 0.009 C, Lawn, Flat 5.721 C, Lawn, Mod 2.914 C, Lawn, Steep 0.058 Pervious Total 13.955 Impervious Land Use acre ROADS MOD 5.839 Impervious Total 5.839 Basin Total 19.794 Element Flows To: Surface Interflow Groundwater Heather Downs Pond Heather Downs Pond DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 9 Routing Elements Predeveloped Routing Fernwood Pond Depth:3 ft. Discharge Structure: 1 Riser Height:3 ft. Riser Diameter:12 in. Orifice 1 Diameter:4 in.Elevation:-0.19 ft. Element Flows To: Outlet 1 Outlet 2 Heather Downs Pond SSD Table Hydraulic Table Stage Area Volume Outlet (feet) (ac.) (ac-ft.) Struct NotUsed NotUsed NotUsed NotUsed 0.000 0.000 0.000 0.189 0.000 0.000 0.000 0.000 1.000 0.019 0.010 0.474 0.000 0.000 0.000 0.000 2.000 0.085 0.062 0.643 0.000 0.000 0.000 0.000 3.000 0.103 0.156 0.775 0.000 0.000 0.000 0.000 4.000 0.109 0.262 4.038 0.000 0.000 0.000 0.000 DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 10 Heather Downs Pond Bottom Length:98.30 ft. Bottom Width:58.00 ft. Depth:6.4 ft. Volume at riser head:0.6494 acre-feet. Side slope 1:1 To 1 Side slope 2:1 To 1 Side slope 3:1 To 1 Side slope 4:1 To 1 Discharge Structure Riser Height:4.4 ft. Riser Diameter:12 in. Orifice 1 Diameter:2.5 in.Elevation:-1.2 ft. Orifice 2 Diameter:2.75 in.Elevation:1.9 ft. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 369.32 0.130 0.000 0.185 0.000 369.39 0.131 0.009 0.191 0.000 369.46 0.131 0.018 0.196 0.000 369.53 0.132 0.028 0.201 0.000 369.60 0.132 0.037 0.206 0.000 369.68 0.133 0.047 0.211 0.000 369.75 0.134 0.056 0.216 0.000 369.82 0.134 0.066 0.221 0.000 369.89 0.135 0.075 0.225 0.000 369.96 0.135 0.085 0.230 0.000 370.03 0.136 0.094 0.234 0.000 370.10 0.136 0.104 0.238 0.000 370.17 0.137 0.114 0.243 0.000 370.24 0.137 0.124 0.247 0.000 370.32 0.138 0.133 0.251 0.000 370.39 0.138 0.143 0.255 0.000 370.46 0.139 0.153 0.259 0.000 370.53 0.139 0.163 0.263 0.000 370.60 0.140 0.173 0.267 0.000 370.67 0.140 0.183 0.270 0.000 370.74 0.141 0.193 0.274 0.000 370.81 0.141 0.203 0.278 0.000 370.88 0.142 0.213 0.282 0.000 370.96 0.142 0.223 0.285 0.000 371.03 0.143 0.234 0.289 0.000 371.10 0.143 0.244 0.292 0.000 371.17 0.144 0.254 0.296 0.000 371.24 0.145 0.264 0.328 0.000 371.31 0.145 0.275 0.364 0.000 371.38 0.146 0.285 0.389 0.000 371.45 0.146 0.295 0.408 0.000 371.52 0.147 0.306 0.426 0.000 371.60 0.147 0.316 0.442 0.000 371.67 0.148 0.327 0.456 0.000 371.74 0.148 0.337 0.470 0.000 371.81 0.149 0.348 0.483 0.000 DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 11 371.88 0.149 0.359 0.495 0.000 371.95 0.150 0.369 0.507 0.000 372.02 0.150 0.380 0.518 0.000 372.09 0.151 0.391 0.529 0.000 372.16 0.152 0.402 0.540 0.000 372.24 0.152 0.412 0.550 0.000 372.31 0.153 0.423 0.561 0.000 372.38 0.153 0.434 0.570 0.000 372.45 0.154 0.445 0.580 0.000 372.52 0.154 0.456 0.589 0.000 372.59 0.155 0.467 0.598 0.000 372.66 0.155 0.478 0.607 0.000 372.73 0.156 0.489 0.616 0.000 372.80 0.157 0.500 0.625 0.000 372.88 0.157 0.512 0.633 0.000 372.95 0.158 0.523 0.642 0.000 373.02 0.158 0.534 0.650 0.000 373.09 0.159 0.545 0.658 0.000 373.16 0.159 0.557 0.666 0.000 373.23 0.160 0.568 0.674 0.000 373.30 0.160 0.580 0.682 0.000 373.37 0.161 0.591 0.689 0.000 373.44 0.162 0.603 0.697 0.000 373.52 0.162 0.614 0.704 0.000 373.59 0.163 0.626 0.712 0.000 373.66 0.163 0.637 0.719 0.000 373.73 0.164 0.649 0.735 0.000 373.80 0.164 0.661 0.973 0.000 373.87 0.165 0.672 1.352 0.000 373.94 0.166 0.684 1.793 0.000 374.01 0.166 0.696 2.227 0.000 374.08 0.167 0.708 2.586 0.000 374.16 0.167 0.720 2.834 0.000 374.23 0.168 0.732 3.016 0.000 374.30 0.168 0.744 3.175 0.000 374.37 0.169 0.756 3.325 0.000 374.44 0.170 0.768 3.467 0.000 374.51 0.170 0.780 3.602 0.000 374.58 0.171 0.792 3.732 0.000 374.65 0.171 0.804 3.856 0.000 374.72 0.172 0.817 3.976 0.000 374.80 0.172 0.829 4.092 0.000 374.87 0.173 0.841 4.205 0.000 374.94 0.174 0.854 4.314 0.000 375.01 0.174 0.866 4.420 0.000 375.08 0.175 0.878 4.523 0.000 375.15 0.175 0.891 4.624 0.000 375.22 0.176 0.903 4.722 0.000 375.29 0.177 0.916 4.819 0.000 375.36 0.177 0.929 4.913 0.000 375.44 0.178 0.941 5.005 0.000 375.51 0.178 0.954 5.095 0.000 375.58 0.179 0.967 5.184 0.000 375.65 0.180 0.979 5.271 0.000 375.72 0.180 0.992 5.357 0.000 375.79 0.181 1.005 5.441 0.000 DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 12 Mitigated Routing Fernwood Pond Depth:3 ft. Discharge Structure: 1 Riser Height:3 ft. Riser Diameter:12 in. Orifice 1 Diameter:4 in.Elevation:-0.19 ft. Element Flows To: Outlet 1 Outlet 2 Heather Downs Pond SSD Table Hydraulic Table Stage Area Volume Outlet (feet) (ac.) (ac-ft.) Struct NotUsed NotUsed NotUsed NotUsed 0.000 0.000 0.000 0.189 0.000 0.000 0.000 0.000 1.000 0.019 0.010 0.474 0.000 0.000 0.000 0.000 2.000 0.085 0.062 0.643 0.000 0.000 0.000 0.000 3.000 0.103 0.156 0.775 0.000 0.000 0.000 0.000 4.000 0.109 0.262 4.038 0.000 0.000 0.000 0.000 DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 13 Heather Downs Pond Bottom Length:98.30 ft. Bottom Width:58.00 ft. Depth:6.4 ft. Volume at riser head:0.6494 acre-feet. Side slope 1:1 To 1 Side slope 2:1 To 1 Side slope 3:1 To 1 Side slope 4:1 To 1 Discharge Structure Riser Height:4.4 ft. Riser Diameter:12 in. Orifice 1 Diameter:2.5 in.Elevation:-1.2 ft. Orifice 2 Diameter:2.75 in.Elevation:1.9 ft. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 369.32 0.130 0.000 0.185 0.000 369.39 0.131 0.009 0.191 0.000 369.46 0.131 0.018 0.196 0.000 369.53 0.132 0.028 0.201 0.000 369.60 0.132 0.037 0.206 0.000 369.68 0.133 0.047 0.211 0.000 369.75 0.134 0.056 0.216 0.000 369.82 0.134 0.066 0.221 0.000 369.89 0.135 0.075 0.225 0.000 369.96 0.135 0.085 0.230 0.000 370.03 0.136 0.094 0.234 0.000 370.10 0.136 0.104 0.238 0.000 370.17 0.137 0.114 0.243 0.000 370.24 0.137 0.124 0.247 0.000 370.32 0.138 0.133 0.251 0.000 370.39 0.138 0.143 0.255 0.000 370.46 0.139 0.153 0.259 0.000 370.53 0.139 0.163 0.263 0.000 370.60 0.140 0.173 0.267 0.000 370.67 0.140 0.183 0.270 0.000 370.74 0.141 0.193 0.274 0.000 370.81 0.141 0.203 0.278 0.000 370.88 0.142 0.213 0.282 0.000 370.96 0.142 0.223 0.285 0.000 371.03 0.143 0.234 0.289 0.000 371.10 0.143 0.244 0.292 0.000 371.17 0.144 0.254 0.296 0.000 371.24 0.145 0.264 0.328 0.000 371.31 0.145 0.275 0.364 0.000 371.38 0.146 0.285 0.389 0.000 371.45 0.146 0.295 0.408 0.000 371.52 0.147 0.306 0.426 0.000 371.60 0.147 0.316 0.442 0.000 371.67 0.148 0.327 0.456 0.000 371.74 0.148 0.337 0.470 0.000 371.81 0.149 0.348 0.483 0.000 DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 14 371.88 0.149 0.359 0.495 0.000 371.95 0.150 0.369 0.507 0.000 372.02 0.150 0.380 0.518 0.000 372.09 0.151 0.391 0.529 0.000 372.16 0.152 0.402 0.540 0.000 372.24 0.152 0.412 0.550 0.000 372.31 0.153 0.423 0.561 0.000 372.38 0.153 0.434 0.570 0.000 372.45 0.154 0.445 0.580 0.000 372.52 0.154 0.456 0.589 0.000 372.59 0.155 0.467 0.598 0.000 372.66 0.155 0.478 0.607 0.000 372.73 0.156 0.489 0.616 0.000 372.80 0.157 0.500 0.625 0.000 372.88 0.157 0.512 0.633 0.000 372.95 0.158 0.523 0.642 0.000 373.02 0.158 0.534 0.650 0.000 373.09 0.159 0.545 0.658 0.000 373.16 0.159 0.557 0.666 0.000 373.23 0.160 0.568 0.674 0.000 373.30 0.160 0.580 0.682 0.000 373.37 0.161 0.591 0.689 0.000 373.44 0.162 0.603 0.697 0.000 373.52 0.162 0.614 0.704 0.000 373.59 0.163 0.626 0.712 0.000 373.66 0.163 0.637 0.719 0.000 373.73 0.164 0.649 0.735 0.000 373.80 0.164 0.661 0.973 0.000 373.87 0.165 0.672 1.352 0.000 373.94 0.166 0.684 1.793 0.000 374.01 0.166 0.696 2.227 0.000 374.08 0.167 0.708 2.586 0.000 374.16 0.167 0.720 2.834 0.000 374.23 0.168 0.732 3.016 0.000 374.30 0.168 0.744 3.175 0.000 374.37 0.169 0.756 3.325 0.000 374.44 0.170 0.768 3.467 0.000 374.51 0.170 0.780 3.602 0.000 374.58 0.171 0.792 3.732 0.000 374.65 0.171 0.804 3.856 0.000 374.72 0.172 0.817 3.976 0.000 374.80 0.172 0.829 4.092 0.000 374.87 0.173 0.841 4.205 0.000 374.94 0.174 0.854 4.314 0.000 375.01 0.174 0.866 4.420 0.000 375.08 0.175 0.878 4.523 0.000 375.15 0.175 0.891 4.624 0.000 375.22 0.176 0.903 4.722 0.000 375.29 0.177 0.916 4.819 0.000 375.36 0.177 0.929 4.913 0.000 375.44 0.178 0.941 5.005 0.000 375.51 0.178 0.954 5.095 0.000 375.58 0.179 0.967 5.184 0.000 375.65 0.180 0.979 5.271 0.000 375.72 0.180 0.992 5.357 0.000 375.79 0.181 1.005 5.441 0.000 DRAFTExisting model_trap pond_new datum 4/16/2019 2:15:33 PM Page 15 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:20.26 Total Impervious Area:8.642 Mitigated Landuse Totals for POC #1 Total Pervious Area:20.26 Total Impervious Area:8.642 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 1.8729 5 year 3.136375 10 year 4.034902 25 year 5.210279 50 year 6.10306 100 year 7.003646 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.8729 5 year 3.136375 10 year 4.034902 25 year 5.210279 50 year 6.10306 100 year 7.003646 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 2.487 2.487 1950 3.464 3.464 1951 3.135 3.135 1952 0.743 0.743 1953 0.905 0.905 1954 0.932 0.932 1955 2.575 2.575 1956 2.469 2.469 1957 3.096 3.096 1958 1.857 1.857 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:02 PM Page 16 1959 1.494 1.494 1960 2.894 2.894 1961 1.366 1.366 1962 0.633 0.633 1963 1.482 1.482 1964 1.165 1.165 1965 1.573 1.573 1966 0.673 0.673 1967 3.744 3.744 1968 1.536 1.536 1969 2.338 2.338 1970 1.787 1.787 1971 2.750 2.750 1972 3.443 3.443 1973 1.187 1.187 1974 0.696 0.696 1975 3.133 3.133 1976 1.849 1.849 1977 0.606 0.606 1978 1.401 1.401 1979 0.647 0.647 1980 2.959 2.959 1981 1.649 1.649 1982 3.997 3.997 1983 1.931 1.931 1984 0.712 0.712 1985 1.568 1.568 1986 2.938 2.938 1987 2.839 2.839 1988 0.734 0.734 1989 0.617 0.617 1990 5.297 5.297 1991 4.410 4.410 1992 1.264 1.264 1993 1.501 1.501 1994 0.547 0.547 1995 2.085 2.085 1996 3.329 3.329 1997 2.708 2.708 1998 2.158 2.158 1999 2.544 2.544 2000 1.770 1.770 2001 0.657 0.657 2002 3.579 3.579 2003 0.665 0.665 2004 4.550 4.550 2005 2.746 2.746 2006 2.549 2.549 2007 4.316 4.316 2008 4.704 4.704 2009 3.310 3.310 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 5.2969 5.2969 2 4.7044 4.7044 3 4.5498 4.5498 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:02 PM Page 17 4 4.4100 4.4100 5 4.3164 4.3164 6 3.9968 3.9968 7 3.7438 3.7438 8 3.5792 3.5792 9 3.4635 3.4635 10 3.4435 3.4435 11 3.3289 3.3289 12 3.3097 3.3097 13 3.1354 3.1354 14 3.1327 3.1327 15 3.0963 3.0963 16 2.9590 2.9590 17 2.9377 2.9377 18 2.8937 2.8937 19 2.8394 2.8394 20 2.7497 2.7497 21 2.7456 2.7456 22 2.7080 2.7080 23 2.5754 2.5754 24 2.5494 2.5494 25 2.5442 2.5442 26 2.4866 2.4866 27 2.4694 2.4694 28 2.3381 2.3381 29 2.1578 2.1578 30 2.0849 2.0849 31 1.9312 1.9312 32 1.8573 1.8573 33 1.8495 1.8495 34 1.7871 1.7871 35 1.7699 1.7699 36 1.6491 1.6491 37 1.5725 1.5725 38 1.5679 1.5679 39 1.5358 1.5358 40 1.5006 1.5006 41 1.4941 1.4941 42 1.4821 1.4821 43 1.4012 1.4012 44 1.3659 1.3659 45 1.2641 1.2641 46 1.1870 1.1870 47 1.1654 1.1654 48 0.9324 0.9324 49 0.9051 0.9051 50 0.7428 0.7428 51 0.7339 0.7339 52 0.7123 0.7123 53 0.6956 0.6956 54 0.6728 0.6728 55 0.6653 0.6653 56 0.6569 0.6569 57 0.6468 0.6468 58 0.6333 0.6333 59 0.6166 0.6166 60 0.6058 0.6058 61 0.5466 0.5466 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:02 PM Page 18 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:02 PM Page 19 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.9365 2479 2479 100 Pass 0.9886 2331 2331 100 Pass 1.0408 2205 2205 100 Pass 1.0930 2060 2060 100 Pass 1.1452 1937 1937 100 Pass 1.1974 1814 1814 100 Pass 1.2496 1691 1691 100 Pass 1.3018 1558 1558 100 Pass 1.3540 1457 1457 100 Pass 1.4061 1362 1362 100 Pass 1.4583 1264 1264 100 Pass 1.5105 1185 1185 100 Pass 1.5627 1116 1116 100 Pass 1.6149 1045 1045 100 Pass 1.6671 972 972 100 Pass 1.7193 901 901 100 Pass 1.7715 850 850 100 Pass 1.8236 802 802 100 Pass 1.8758 753 753 100 Pass 1.9280 706 706 100 Pass 1.9802 662 662 100 Pass 2.0324 622 622 100 Pass 2.0846 589 589 100 Pass 2.1368 551 551 100 Pass 2.1890 517 517 100 Pass 2.2411 486 486 100 Pass 2.2933 455 455 100 Pass 2.3455 415 415 100 Pass 2.3977 383 383 100 Pass 2.4499 363 363 100 Pass 2.5021 342 342 100 Pass 2.5543 319 319 100 Pass 2.6065 308 308 100 Pass 2.6587 291 291 100 Pass 2.7108 270 270 100 Pass 2.7630 257 257 100 Pass 2.8152 244 244 100 Pass 2.8674 228 228 100 Pass 2.9196 222 222 100 Pass 2.9718 208 208 100 Pass 3.0240 195 195 100 Pass 3.0762 187 187 100 Pass 3.1283 178 178 100 Pass 3.1805 168 168 100 Pass 3.2327 165 165 100 Pass 3.2849 151 151 100 Pass 3.3371 140 140 100 Pass 3.3893 132 132 100 Pass 3.4415 123 123 100 Pass 3.4937 113 113 100 Pass 3.5458 109 109 100 Pass 3.5980 104 104 100 Pass 3.6502 97 97 100 Pass DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:02 PM Page 20 3.7024 88 88 100 Pass 3.7546 79 79 100 Pass 3.8068 75 75 100 Pass 3.8590 70 70 100 Pass 3.9112 66 66 100 Pass 3.9634 58 58 100 Pass 4.0155 54 54 100 Pass 4.0677 48 48 100 Pass 4.1199 45 45 100 Pass 4.1721 40 40 100 Pass 4.2243 36 36 100 Pass 4.2765 33 33 100 Pass 4.3287 27 27 100 Pass 4.3809 24 24 100 Pass 4.4330 20 20 100 Pass 4.4852 16 16 100 Pass 4.5374 14 14 100 Pass 4.5896 13 13 100 Pass 4.6418 12 12 100 Pass 4.6940 12 12 100 Pass 4.7462 11 11 100 Pass 4.7984 10 10 100 Pass 4.8505 10 10 100 Pass 4.9027 10 10 100 Pass 4.9549 9 9 100 Pass 5.0071 6 6 100 Pass 5.0593 4 4 100 Pass 5.1115 4 4 100 Pass 5.1637 2 2 100 Pass 5.2159 2 2 100 Pass 5.2681 1 1 100 Pass 5.3202 0 0 100 Pass 5.3724 0 0 0 Pass 5.4246 0 0 0 Pass 5.4768 0 0 0 Pass 5.5290 0 0 0 Pass 5.5812 0 0 0 Pass 5.6334 0 0 0 Pass 5.6856 0 0 0 Pass 5.7377 0 0 0 Pass 5.7899 0 0 0 Pass 5.8421 0 0 0 Pass 5.8943 0 0 0 Pass 5.9465 0 0 0 Pass 5.9987 0 0 0 Pass 6.0509 0 0 0 Pass 6.1031 0 0 0 Pass DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:02 PM Page 21 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:1.1127 acre-feet On-line facility target flow:0.6377 cfs. Adjusted for 15 min:0.6377 cfs. Off-line facility target flow:0.3824 cfs. Adjusted for 15 min:0.3824 cfs. DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:02 PM Page 22 LID Report DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:10 PM Page 23 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:10 PM Page 24 Appendix Predeveloped Schematic DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:10 PM Page 25 Mitigated Schematic DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 26 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Existing model_trap pond_new datum.wdm MESSU 25 PreExisting model_trap pond_new datum.MES 27 PreExisting model_trap pond_new datum.L61 28 PreExisting model_trap pond_new datum.L62 30 POCExisting model_trap pond_new datum1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 7 PERLND 8 IMPLND 2 PERLND 9 PERLND 16 PERLND 17 PERLND 18 RCHRES 1 RCHRES 2 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Heather Downs Pond MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 7 A/B, Lawn, Flat 1 1 1 1 27 0 8 A/B, Lawn, Mod 1 1 1 1 27 0 9 A/B, Lawn, Steep 1 1 1 1 27 0 16 C, Lawn, Flat 1 1 1 1 27 0 17 C, Lawn, Mod 1 1 1 1 27 0 18 C, Lawn, Steep 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 27 ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 7 0 0 1 0 0 0 0 0 0 0 0 0 8 0 0 1 0 0 0 0 0 0 0 0 0 9 0 0 1 0 0 0 0 0 0 0 0 0 16 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 18 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 7 0 0 4 0 0 0 0 0 0 0 0 0 1 9 8 0 0 4 0 0 0 0 0 0 0 0 0 1 9 9 0 0 4 0 0 0 0 0 0 0 0 0 1 9 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 18 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 7 0 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 7 0 5 0.8 400 0.05 0.3 0.996 8 0 5 0.8 400 0.1 0.3 0.996 9 0 5 0.8 400 0.15 0.3 0.996 16 0 4.5 0.03 400 0.05 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 18 0 4.5 0.03 400 0.15 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 7 0 0 2 2 0 0 0 8 0 0 2 2 0 0 0 9 0 0 2 2 0 0 0 16 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 18 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 7 0.1 0.5 0.25 0 0.7 0.25 8 0.1 0.5 0.25 0 0.7 0.25 9 0.1 0.5 0.25 0 0.7 0.25 16 0.1 0.25 0.25 6 0.5 0.25 17 0.1 0.25 0.25 6 0.5 0.25 18 0.1 0.15 0.25 6 0.3 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 28 7 0 0 0 0 3 1 0 8 0 0 0 0 3 1 0 9 0 0 0 0 3 1 0 16 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 18 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 2 ROADS/MOD 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 2 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 2 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 2 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 2 400 0.05 0.1 0.08 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 2 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 2 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 7 2.116 RCHRES 2 2 PERLND 7 2.116 RCHRES 2 3 PERLND 8 0.387 RCHRES 2 2 PERLND 8 0.387 RCHRES 2 3 IMPLND 2 1.145 RCHRES 2 5 Basin 2*** PERLND 7 3.213 RCHRES 1 2 PERLND 7 3.213 RCHRES 1 3 PERLND 8 0.557 RCHRES 1 2 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 29 PERLND 8 0.557 RCHRES 1 3 PERLND 9 0.032 RCHRES 1 2 PERLND 9 0.032 RCHRES 1 3 IMPLND 2 1.658 RCHRES 1 5 Basin 3*** PERLND 7 3.292 RCHRES 2 2 PERLND 7 3.292 RCHRES 2 3 PERLND 8 1.961 RCHRES 2 2 PERLND 8 1.961 RCHRES 2 3 PERLND 9 0.009 RCHRES 2 2 PERLND 9 0.009 RCHRES 2 3 PERLND 16 5.721 RCHRES 2 2 PERLND 16 5.721 RCHRES 2 3 PERLND 17 2.914 RCHRES 2 2 PERLND 17 2.914 RCHRES 2 3 PERLND 18 0.058 RCHRES 2 2 PERLND 18 0.058 RCHRES 2 3 IMPLND 2 5.839 RCHRES 2 5 ******Routing****** RCHRES 1 1 RCHRES 2 6 RCHRES 2 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Fernwood Pond 1 1 1 1 28 0 1 2 Heather Downs Po-028 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 2 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 30 <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.5 0.0 2 2 0.02 0.0 369.32 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 5 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.000000 0.000000 0.189259 1.000000 0.019283 0.009642 0.473644 2.000000 0.084940 0.061754 0.642541 3.000000 0.102846 0.155647 0.775486 4.000000 0.109182 0.261662 4.038393 END FTABLE 1 FTABLE 2 91 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.130886 0.000000 0.185793 0.071111 0.131397 0.009326 0.191219 0.142222 0.131909 0.018688 0.196495 0.213333 0.132421 0.028086 0.201633 0.284444 0.132935 0.037521 0.206643 0.355556 0.133449 0.046992 0.211535 0.426667 0.133965 0.056500 0.216316 0.497778 0.134481 0.066045 0.220993 0.568889 0.134998 0.075627 0.225574 0.640000 0.135517 0.085245 0.230063 0.711111 0.136036 0.094900 0.234467 0.782222 0.136556 0.104592 0.238789 0.853333 0.137077 0.114321 0.243035 0.924444 0.137599 0.124088 0.247207 0.995556 0.138122 0.133891 0.251311 1.066667 0.138645 0.143732 0.255348 1.137778 0.139170 0.153610 0.259323 1.208889 0.139696 0.163525 0.263237 1.280000 0.140222 0.173477 0.267094 1.351111 0.140750 0.183467 0.270897 1.422222 0.141278 0.193495 0.274646 1.493333 0.141808 0.203560 0.278345 1.564444 0.142338 0.213663 0.281996 1.635556 0.142869 0.223804 0.285600 1.706667 0.143401 0.233983 0.289159 1.777778 0.143934 0.244199 0.292674 1.848889 0.144468 0.254453 0.296149 1.920000 0.145003 0.264746 0.328605 1.991111 0.145539 0.275076 0.364923 2.062222 0.146076 0.285444 0.388991 2.133333 0.146614 0.295851 0.408787 2.204444 0.147152 0.306296 0.426175 2.275556 0.147692 0.316780 0.441957 2.346667 0.148232 0.327301 0.456567 2.417778 0.148774 0.337861 0.470268 2.488889 0.149316 0.348460 0.483237 2.560000 0.149859 0.359098 0.495600 2.631111 0.150403 0.369774 0.507447 2.702222 0.150949 0.380488 0.518849 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 31 2.773333 0.151495 0.391242 0.529862 2.844444 0.152042 0.402034 0.540529 2.915556 0.152590 0.412866 0.550887 2.986667 0.153138 0.423736 0.560965 3.057778 0.153688 0.434645 0.570789 3.128889 0.154239 0.445594 0.580379 3.200000 0.154791 0.456582 0.589756 3.271111 0.155343 0.467609 0.598934 3.342222 0.155897 0.478675 0.607927 3.413333 0.156451 0.489781 0.616748 3.484444 0.157006 0.500926 0.625409 3.555556 0.157563 0.512110 0.633918 3.626667 0.158120 0.523335 0.642284 3.697778 0.158678 0.534599 0.650516 3.768889 0.159237 0.545902 0.658620 3.840000 0.159797 0.557246 0.666604 3.911111 0.160358 0.568629 0.674472 3.982222 0.160920 0.580052 0.682231 4.053333 0.161483 0.591515 0.689885 4.124444 0.162046 0.603019 0.697439 4.195556 0.162611 0.614562 0.704898 4.266667 0.163177 0.626146 0.712265 4.337778 0.163743 0.637769 0.719544 4.408889 0.164311 0.649434 0.735635 4.480000 0.164879 0.661138 0.973124 4.551111 0.165448 0.672883 1.352148 4.622222 0.166019 0.684669 1.793874 4.693333 0.166590 0.696495 2.227320 4.764444 0.167162 0.708361 2.586783 4.835556 0.167735 0.720269 2.834156 4.906667 0.168309 0.732217 3.016895 4.977778 0.168884 0.744206 3.175676 5.048889 0.169459 0.756236 3.325285 5.120000 0.170036 0.768307 3.467188 5.191111 0.170614 0.780419 3.602495 5.262222 0.171192 0.792572 3.732072 5.333333 0.171772 0.804766 3.856610 5.404444 0.172352 0.817002 3.976670 5.475556 0.172934 0.829279 4.092717 5.546667 0.173516 0.841597 4.205138 5.617778 0.174099 0.853957 4.314264 5.688889 0.174683 0.866358 4.420374 5.760000 0.175268 0.878800 4.523714 5.831111 0.175854 0.891285 4.624496 5.902222 0.176441 0.903811 4.722905 5.973333 0.177029 0.916379 4.819106 6.044444 0.177618 0.928988 4.913246 6.115556 0.178208 0.941640 5.005455 6.186667 0.178798 0.954333 5.095849 6.257778 0.179390 0.967069 5.184536 6.328889 0.179982 0.979847 5.271611 6.400000 0.180576 0.992667 5.357160 END FTABLE 2 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 2 PREC ENGL 1 RCHRES 1 EXTNL PREC WDM 2 PREC ENGL 1 RCHRES 2 EXTNL PREC WDM 1 EVAP ENGL 0.76 RCHRES 1 EXTNL POTEV WDM 1 EVAP ENGL 0.76 RCHRES 2 EXTNL POTEV END EXT SOURCES EXT TARGETS DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 32 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1002 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1003 STAG ENGL REPL RCHRES 2 HYDR RO 1 1 1 WDM 1006 FLOW ENGL REPL RCHRES 2 HYDR STAGE 1 1 1 WDM 1007 STAG ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 6 RCHRES ROFLOW RCHRES INFLOW END MASS-LINK 6 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK END RUN DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 33 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Existing model_trap pond_new datum.wdm MESSU 25 MitExisting model_trap pond_new datum.MES 27 MitExisting model_trap pond_new datum.L61 28 MitExisting model_trap pond_new datum.L62 30 POCExisting model_trap pond_new datum1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 7 PERLND 8 IMPLND 2 PERLND 9 PERLND 16 PERLND 17 PERLND 18 RCHRES 1 RCHRES 2 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Heather Downs Pond MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 7 A/B, Lawn, Flat 1 1 1 1 27 0 8 A/B, Lawn, Mod 1 1 1 1 27 0 9 A/B, Lawn, Steep 1 1 1 1 27 0 16 C, Lawn, Flat 1 1 1 1 27 0 17 C, Lawn, Mod 1 1 1 1 27 0 18 C, Lawn, Steep 1 1 1 1 27 0 END GEN-INFO DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 34 *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 7 0 0 1 0 0 0 0 0 0 0 0 0 8 0 0 1 0 0 0 0 0 0 0 0 0 9 0 0 1 0 0 0 0 0 0 0 0 0 16 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 18 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 7 0 0 4 0 0 0 0 0 0 0 0 0 1 9 8 0 0 4 0 0 0 0 0 0 0 0 0 1 9 9 0 0 4 0 0 0 0 0 0 0 0 0 1 9 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 18 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 7 0 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 7 0 5 0.8 400 0.05 0.3 0.996 8 0 5 0.8 400 0.1 0.3 0.996 9 0 5 0.8 400 0.15 0.3 0.996 16 0 4.5 0.03 400 0.05 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 18 0 4.5 0.03 400 0.15 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 7 0 0 2 2 0 0 0 8 0 0 2 2 0 0 0 9 0 0 2 2 0 0 0 16 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 18 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 7 0.1 0.5 0.25 0 0.7 0.25 8 0.1 0.5 0.25 0 0.7 0.25 9 0.1 0.5 0.25 0 0.7 0.25 16 0.1 0.25 0.25 6 0.5 0.25 17 0.1 0.25 0.25 6 0.5 0.25 18 0.1 0.15 0.25 6 0.3 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 35 # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 7 0 0 0 0 3 1 0 8 0 0 0 0 3 1 0 9 0 0 0 0 3 1 0 16 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 18 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 2 ROADS/MOD 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 2 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 2 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 2 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 2 400 0.05 0.1 0.08 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 2 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 2 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 7 2.116 RCHRES 2 2 PERLND 7 2.116 RCHRES 2 3 PERLND 8 0.387 RCHRES 2 2 PERLND 8 0.387 RCHRES 2 3 IMPLND 2 1.145 RCHRES 2 5 Basin 2*** PERLND 7 3.213 RCHRES 1 2 PERLND 7 3.213 RCHRES 1 3 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 36 PERLND 8 0.557 RCHRES 1 2 PERLND 8 0.557 RCHRES 1 3 PERLND 9 0.032 RCHRES 1 2 PERLND 9 0.032 RCHRES 1 3 IMPLND 2 1.658 RCHRES 1 5 Basin 3*** PERLND 7 3.292 RCHRES 2 2 PERLND 7 3.292 RCHRES 2 3 PERLND 8 1.961 RCHRES 2 2 PERLND 8 1.961 RCHRES 2 3 PERLND 9 0.009 RCHRES 2 2 PERLND 9 0.009 RCHRES 2 3 PERLND 16 5.721 RCHRES 2 2 PERLND 16 5.721 RCHRES 2 3 PERLND 17 2.914 RCHRES 2 2 PERLND 17 2.914 RCHRES 2 3 PERLND 18 0.058 RCHRES 2 2 PERLND 18 0.058 RCHRES 2 3 IMPLND 2 5.839 RCHRES 2 5 ******Routing****** PERLND 7 2.116 COPY 1 12 PERLND 8 0.387 COPY 1 12 IMPLND 2 1.145 COPY 1 15 PERLND 7 2.116 COPY 1 13 PERLND 8 0.387 COPY 1 13 PERLND 7 3.292 COPY 1 12 PERLND 8 1.961 COPY 1 12 PERLND 9 0.009 COPY 1 12 PERLND 16 5.721 COPY 1 12 PERLND 17 2.914 COPY 1 12 PERLND 18 0.058 COPY 1 12 IMPLND 2 5.839 COPY 1 15 PERLND 7 3.292 COPY 1 13 PERLND 8 1.961 COPY 1 13 PERLND 9 0.009 COPY 1 13 PERLND 16 5.721 COPY 1 13 PERLND 17 2.914 COPY 1 13 PERLND 18 0.058 COPY 1 13 RCHRES 1 1 RCHRES 2 6 RCHRES 1 COPY 1 16 RCHRES 2 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Fernwood Pond 1 1 1 1 28 0 1 2 Heather Downs Po-044 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 37 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 2 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.5 0.0 2 2 0.02 0.0 369.32 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 5 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.000000 0.000000 0.189259 1.000000 0.019283 0.009642 0.473644 2.000000 0.084940 0.061754 0.642541 3.000000 0.102846 0.155647 0.775486 4.000000 0.109182 0.261662 4.038393 END FTABLE 1 FTABLE 2 91 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.130886 0.000000 0.185793 0.071111 0.131397 0.009326 0.191219 0.142222 0.131909 0.018688 0.196495 0.213333 0.132421 0.028086 0.201633 0.284444 0.132935 0.037521 0.206643 0.355556 0.133449 0.046992 0.211535 0.426667 0.133965 0.056500 0.216316 0.497778 0.134481 0.066045 0.220993 0.568889 0.134998 0.075627 0.225574 0.640000 0.135517 0.085245 0.230063 0.711111 0.136036 0.094900 0.234467 0.782222 0.136556 0.104592 0.238789 0.853333 0.137077 0.114321 0.243035 0.924444 0.137599 0.124088 0.247207 0.995556 0.138122 0.133891 0.251311 1.066667 0.138645 0.143732 0.255348 1.137778 0.139170 0.153610 0.259323 1.208889 0.139696 0.163525 0.263237 1.280000 0.140222 0.173477 0.267094 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 38 1.351111 0.140750 0.183467 0.270897 1.422222 0.141278 0.193495 0.274646 1.493333 0.141808 0.203560 0.278345 1.564444 0.142338 0.213663 0.281996 1.635556 0.142869 0.223804 0.285600 1.706667 0.143401 0.233983 0.289159 1.777778 0.143934 0.244199 0.292674 1.848889 0.144468 0.254453 0.296149 1.920000 0.145003 0.264746 0.328605 1.991111 0.145539 0.275076 0.364923 2.062222 0.146076 0.285444 0.388991 2.133333 0.146614 0.295851 0.408787 2.204444 0.147152 0.306296 0.426175 2.275556 0.147692 0.316780 0.441957 2.346667 0.148232 0.327301 0.456567 2.417778 0.148774 0.337861 0.470268 2.488889 0.149316 0.348460 0.483237 2.560000 0.149859 0.359098 0.495600 2.631111 0.150403 0.369774 0.507447 2.702222 0.150949 0.380488 0.518849 2.773333 0.151495 0.391242 0.529862 2.844444 0.152042 0.402034 0.540529 2.915556 0.152590 0.412866 0.550887 2.986667 0.153138 0.423736 0.560965 3.057778 0.153688 0.434645 0.570789 3.128889 0.154239 0.445594 0.580379 3.200000 0.154791 0.456582 0.589756 3.271111 0.155343 0.467609 0.598934 3.342222 0.155897 0.478675 0.607927 3.413333 0.156451 0.489781 0.616748 3.484444 0.157006 0.500926 0.625409 3.555556 0.157563 0.512110 0.633918 3.626667 0.158120 0.523335 0.642284 3.697778 0.158678 0.534599 0.650516 3.768889 0.159237 0.545902 0.658620 3.840000 0.159797 0.557246 0.666604 3.911111 0.160358 0.568629 0.674472 3.982222 0.160920 0.580052 0.682231 4.053333 0.161483 0.591515 0.689885 4.124444 0.162046 0.603019 0.697439 4.195556 0.162611 0.614562 0.704898 4.266667 0.163177 0.626146 0.712265 4.337778 0.163743 0.637769 0.719544 4.408889 0.164311 0.649434 0.735635 4.480000 0.164879 0.661138 0.973124 4.551111 0.165448 0.672883 1.352148 4.622222 0.166019 0.684669 1.793874 4.693333 0.166590 0.696495 2.227320 4.764444 0.167162 0.708361 2.586783 4.835556 0.167735 0.720269 2.834156 4.906667 0.168309 0.732217 3.016895 4.977778 0.168884 0.744206 3.175676 5.048889 0.169459 0.756236 3.325285 5.120000 0.170036 0.768307 3.467188 5.191111 0.170614 0.780419 3.602495 5.262222 0.171192 0.792572 3.732072 5.333333 0.171772 0.804766 3.856610 5.404444 0.172352 0.817002 3.976670 5.475556 0.172934 0.829279 4.092717 5.546667 0.173516 0.841597 4.205138 5.617778 0.174099 0.853957 4.314264 5.688889 0.174683 0.866358 4.420374 5.760000 0.175268 0.878800 4.523714 5.831111 0.175854 0.891285 4.624496 5.902222 0.176441 0.903811 4.722905 5.973333 0.177029 0.916379 4.819106 6.044444 0.177618 0.928988 4.913246 6.115556 0.178208 0.941640 5.005455 6.186667 0.178798 0.954333 5.095849 6.257778 0.179390 0.967069 5.184536 DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 39 6.328889 0.179982 0.979847 5.271611 6.400000 0.180576 0.992667 5.357160 END FTABLE 2 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 2 PREC ENGL 1 RCHRES 1 EXTNL PREC WDM 2 PREC ENGL 1 RCHRES 2 EXTNL PREC WDM 1 EVAP ENGL 0.76 RCHRES 1 EXTNL POTEV WDM 1 EVAP ENGL 0.76 RCHRES 2 EXTNL POTEV END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1014 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1015 STAG ENGL REPL RCHRES 2 HYDR RO 1 1 1 WDM 1016 FLOW ENGL REPL RCHRES 2 HYDR STAGE 1 1 1 WDM 1017 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 6 RCHRES ROFLOW RCHRES INFLOW END MASS-LINK 6 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK END RUN DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 40 Predeveloped HSPF Message File DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 41 Mitigated HSPF Message File DRAFTExisting model_trap pond_new datum 4/16/2019 2:16:11 PM Page 42 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2019; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com APPENDIX C COST ESTIMATES APPENDIX This page left intentionally blank. APPENDIX C-1 ALTERNATIVE 1 ESTIMATE APPENDIX This page left intentionally blank. Prepared by: AM Date Prepared 4/18/19Checked by: MSG Date Checked 4/19/19 Alternative 1 Planning Level Design, Permitting, and Construction Cost Estimate Item No.Bid Item Description Quantity Unit Unit Cost Amount Assumptions/Notes 1 MOBILIZATION 1 LS $17,000 $17,000 2 MINOR CHANGES 1 FA $15,000 $15,000 3 PROJECT TEMPORARY TRAFFIC CONTROL 1 LS $5,000 $5,000 4 SURVEYING 1 LS $5,000 $5,000 5 SITE POTHOLES 1 EA $1,200 $1,200 6 SPCC PLAN 1 LS $2,000 $2,000 7 REMOVAL OF STRUCTURES AND OBSTRUCTIONS 1 LS $5,000 $5,000 Other structures beyond those listed 8 REMOVAL OF STORM DRAIN PIPE 12 LF $20 $240 9 REMOVE AND REPLACE CONCRETE SIDEWALK AND DRIVEWAY 20 SY $100 $2,000 10 REMOVE AND REPLACE CONCRETE CURB AND GUTTER 30 LF $40 $1,200 11 PLUGGING EXISTING PIPE 2 EA $300 $600 Plug Exist 12" pipe 12 EROSION/WATER POLLUTION CONTROL 1 LS $10,000 $10,000 13 ADJUST MANHOLE 1 EA $2,000 $2,000 Exist SDMH 2165 14 STORM DRAIN PIPE 12" DIAMETER 10 LF $80 $800 Includes excavation, bedding, pipe, pipe zone backfill 15 STORM DRAIN PIPE 18" DIAMETER 50 LF $100 $5,000 Includes saw cut, excavation, bedding, pipe, pipe zone backfill 16 STORM DRAIN PIPE 24" DIAMETER 5 LF $140 $700 Includes excavation, bedding, pipe, pipe zone backfill 17 TYPE 2 MH 48" WITH BIRDCAGE 1 EA $5,000 $5,000 Emergency Overflow Structure 18 TYPE 2 MH 48"1 EA $5,000 $5,000 19 TYPE 2 MH 54"1 EA $7,000 $7,000 Control Structure 20 CONNECT EXISTING STORM PIPE TO NEW STORM STRUCTURE 4 EA $1,200 $4,800 21 DEWATERING 1 LS $5,000 $5,000 22 EXCAVATION INCL. HAUL AND DISPOSAL 350 CY $45 $15,750 Pond Excavation incl haul-Special provision 23 TRENCH SAFETY SYSTEM 1 LS $2,000 $2,000 24 REMOVAL AND REPLACEMENT OF 6 FEET CHAIN LINK FENCE 15 LF $60 $900 25 20 FEET WIDE GATE 1 LS $1,500 $1,500 26 ASPHALT PATCH 7 SF $15 $100 27 REVEGETATION WITH HYDROSEED 1 LS $1,500 $1,500 28 CRUSHED SURFACE BASE COURSE 80 TON $40 $3,200 8" Depth 29 RECORD DRAWINGS 1 LS $2,000 $2,000 SUBTOTAL CONSTRUCTION COST $126,490 CONSTRUCTION CONTINGENCY 40%$50,596 TOTAL CONSTRUCTION COST WITH CONTINGENCY $178,000 SALES TAX 0.0%$0 Assume No SST Applicable to Road Drainage TOTAL FACILITY CONSTRUCTION COST WITH TAX AND CONTINGENCY $178,000 OTHER APPROXIMATED PROJECT COSTS ADMINISTRATIVE COSTS 5%$9,000 CONSTRUCTION MANAGEMENT/CONSTRUCTION ADMINISTRATION 15%$27,000 SPECIAL TESTING AND INSPECTIONS 2%$4,000 TOTAL ESTIMATED PROJECT COST:$218,000 Estimate based on 2019 dollars, rounded to nearest $1000; costs will need to be adjusted for Time Value of Money (TMV) when programming funds. APPENDIX This page left intentionally blank. APPENDIX This page left intentionally blank. APPENDIX C-2 ALTERNATIVE 2 ESTIMATE Prepared by: AM Date Prepared 4/18/19Checked by: MSG Date Checked 4/19/19 Alternative 2 Planning Level Design, Permitting, and Construction Cost Estimate Item No.Bid Item Description Quantity Unit Unit Cost Amount Assumptions/Notes 1 MOBILIZATION 1 LS $17,000 $17,000 2 MINOR CHANGES 1 FA $15,000 $15,000 3 PROJECT TEMPORARY TRAFFIC CONTROL 1 LS $5,000 $5,000 4 SURVEYING 1 LS $5,000 $5,000 5 SITE POTHOLES 1 EA $1,200 $1,200 6 SPCC PLAN 1 LS $2,000 $2,000 7 REMOVAL OF STRUCTURES AND OBSTRUCTIONS 1 LS $5,000 $5,000 Other structures beyond those listed 8 REMOVAL OF STORM DRAIN PIPE 12 LF $20 $240 9 REMOVE AND REPLACE CONCRETE SIDEWALK AND DRIVEWAY 20 SY $100 $2,000 10 REMOVE AND REPLACE CONCRETE CURB AND GUTTER 30 LF $40 $1,200 11 PLUGGING EXISTING PIPE 2 EA $300 $600 Plug Exist 12" pipe 12 EROSION/WATER POLLUTION CONTROL 1 LS $10,000 $10,000 13 ADJUST MANHOLE 1 EA $2,000 $2,000 Exist SDMH 2165 14 STORM DRAIN PIPE 12" DIAMETER 10 LF $80 $800 Includes saw cut, excavation, bedding, pipe, pipe zone backfill 15 STORM DRAIN PIPE 18" DIAMETER 50 LF $100 $5,000 16 STORM DRAIN PIPE 24" DIAMETER 5 LF $140 $700 17 TYPE 2 MH 48" WITH BIRDCAGE 1 EA $4,000 $5,000 Emergency Overflow Structure 18 TYPE 2 MH 48"1 EA $4,000 $5,000 19 TYPE 2 MH 54"1 EA $7,000 $7,000 Control Structure 20 CONNECT EXISTING STORM PIPE TO NEW STORM STRUCTURE 4 EA $1,200 $4,800 21 DEWATERING 1 LS $5,000 $5,000 22 EXCAVATION INCL. HAUL AND DISPOSAL 400 CY $45 $18,000 Pond Excavation incl haul-Special provision 23 TRENCH SAFETY SYSTEM 1 LS $2,000 $2,000 24 REMOVAL AND REPLACEMENT OF 6 FEET CHAIN LINK FENCE 15 LF $60 $900 25 20 FEET WIDE GATE 1 LS $1,500 $1,500 26 ASPHALT PATCH 7 SF $15 $100 27 REVEGETATION WITH HYDROSEED 1 LS $1,500 $1,500 28 CRUSHED SURFACE BASE COURSE 50 TON $40 $2,000 29 RECORD DRAWINGS 1 LS $2,000 $2,000 SUBTOTAL CONSTRUCTION COST $127,540 CONSTRUCTION CONTINGENCY 40%$51,016 TOTAL CONSTRUCTION COST WITH CONTINGENCY $179,000 SALES TAX 0.0%$0 Assume No SST Applicable to Road Drainage TOTAL FACILITY CONSTRUCTION COST WITH TAX AND CONTINGENCY $179,000 OTHER APPROXIMATED PROJECT COSTS ADMINISTRATIVE COSTS 5%$9,000 CONSTRUCTION MANAGEMENT/CONSTRUCTION ADMINISTRATION 15%$27,000 SPECIAL TESTING AND INSPECTIONS 2%$4,000 TOTAL ESTIMATED PROJECT COST:$219,000 Estimate based on 2019 dollars, rounded to nearest $1000; costs will need to be adjusted for Time Value of Money (TMV) when programming funds. APPENDIX This page left intentionally blank. Prepared by: AM Date Prepared 9/17/19 Checked by: MSG Date Checked 9/18/19 90% Planning Level Design, Permitting, and Construction Cost Estimate Comments/Unit Price Reference Data 1 Item No.Bid Item Description Quantity Unit Unit Cost Amount TASK 1 - PROJECT ADMINISTRATION//MANAGEMENT Estimate N/A N/A $15,000 Estimated at 5% of Construction Budget Estimate based on Similar City projects. TASK 2 - CONSTRUCTION MANAGEMENT/INSPECTION Estimate N/A N/A $29,000 Estimated at 10% of Construction based on City historical averages for less complex projects. 1 MOBILIZATION AND DEMOBILIZATION 1 LS $17,000 $17,000 City Standard of 10% Estimate 2 MINOR CHANGES 1 FA $15,000 $15,000 Engineer Estimate 3 PROJECT TEMPORARY TRAFFIC CONTROL 1 LS $7,000 $7,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. Factored up by 50% for small project. 4 CONSTRUCTION SURVEYING, STAKING AND AS-BUILT DRAWINGS 1 LS $6,000 $6,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. Factored up by 50% for small project. 5 SITE POTHOLES 1 EA $1,200 $1,200 Based on Louis Berger 2019 average subconsuttant cost for Potholes (APS) 6 CONSTRUCTION TWPEC PLAN AND IMPLEMENTATION 1 LS $12,000 $12,000 Engineer Estimate 7 REMOVAL OF STRUCTURES AND OBSTRUCTIONS 1 LS $5,000 $5,000 Based on quanity breakdown of structures and unit price estimates 8 REMOVE AND REPLACE CONCRETE SIDEWALK AND DRIVEWAY 10 SY $108 $1,081 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 9 REMOVE AND REPLACE CONCRETE CURB AND GUTTER 10 LF $45 $445 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 10 CONTROL OF WATER (INCLUDES STORM DRAIN BYPASSES)1 LS $3,000 $3,000 Considered minor item as will be easy to bypass flow in existing system using plugs. 11 STORM DRAIN PIPE 18 INCH DIAMETER-CPEP 50 LF $100 $5,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. (factored up for 18-nch from 12-in) 12 STORM DRAIN PIPE 24 INCH DIAMETER-CPEP 12 LF $140 $1,680 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. (factored up for 18-nch from 12-in) 13 SELECT IMPORTED TRENCH BACKFILL 70 TN $50 $3,500 14 STORM MANHOLE #2165 MODIFICATIONS 1 EA $2,000 $2,000 Considered minor item. Means Construction Site work. 15 TYPE 2 MH 54 EMERGENCY OVERFLOW STRUCTURE 1 EA $5,000 $5,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. (Lid and rim offset by bird cage) 16 TYPE 2 MH 48"1 EA $5,000 $5,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 17 TYPE 2 MH 54" CONTRIOL STRUCTURE 1 EA $7,000 $7,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. (Added $2,000 for Riser and appurtanences) 18 CONNECT EXISTING/NEW STORM PIPE TO EXISTING/NEW STORM STRUCTURE 2 EA $1,200 $2,400 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 19 DEWATERING 1 LS $15,000 $15,000 Engineer Estimate 20 POND EXCAVATION INCL. HAUL AND DISPOSAL 510 CY $45 $22,950 Reference: 2013 City of Renton/10th Street and Anacortes Detention Pond Retrofit (Added 18% inflation and 35% for smaller quantity) 21 TRENCH SAFETY SYSTEMS 1 LS $2,000 $3,000 Reference: 2013 City of Renton/10th Street and Anacortes Detention Pond Retrofit (Added 18% inflation) 22 REMOVAL AND REPLACEMENT OF 6 FEET CHAIN LINK FENCE 360 LF $50 $18,000 Reference: 2019 City of Renton Facility Fencing Project. (added 25% due to working around existing vegetation and small quantity) 23 6 FEET HIGH 20 FEET WIDE GATE 1 LS $2,000 $2,000 Reference: 2019 City of Renton Facility Fencing Project. (added 35% for 20' gate instead of 16' and small quantity) 24 6 FEET HIGH 12 FEET WIDE GATE 1 LS $1,000 $1,000 Reference: 2019 City of Renton Facility Fencing Project. (added 35% for 20' gate instead of 16' and small quantity) 25 HMA CLASS 1/2" - 64-22 PAVEMENT PATCH 3 SY $37 $111 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 26 REVEGETATION WITH HYDROSEED 1 LS $1,800 $1,800 Reference: 2013 City of Renton/10th Street and Anacortes Detention Pond Retrofit 27 CRUSHED SURFACE BASE COURSE 50 TON $53 $2,655 Reference: 2013 City of Renton/10th Street and Anacortes Detention Pond Retrofit 28 DECOMMISSIONING MONITORING WELL 1 EA $3,488 $3,488 Reference: 2016 City of Renton SW 7th Street 29 COMPOST AMEMDED SOIL 170 SY $10 $1,700 Engineer Estimate 30 PLANTS PSIP 900 EA $10 $9,000 31 LOW PERMEABLE LINER MATERIAL 220 CY $35 $7,700 Engineer Estimate SUBTOTAL SCHEDULE A $187,711 CONSTRUCTION CONTINGENCY 25%$75,084 SUBTOTAL SCHEDULE A CONSTRUCTION COST WITH CONTINGENCY $263,000 SALES TAX 0.0%$0 Assume 0% because of drainage associated with Roads TOTAL SCHEDULE A (TASK 1, 2 AND 3)$307,000 TASK 3 - CONSTRUCTION SCHEDULE A - POND RETROFIT 90% Planning Level Design, Permitting, and Construction Cost Estimate Comments/Unit Price Reference Data 1 Item No.Bid Item Description Quantity Unit Unit Cost Amount TASK 1 - PROJECT ADMINISTRATION//MANAGEMENT Estimate N/A N/A $4,000 Estimated at 5% of Construction Budget Estimate based on Similar City projects. TASK 2 - CONSTRUCTION MANAGEMENT/INSPECTION Estimate N/A N/A $9,000 Estimated at 10% of Construction based on City historical averages for less complex projects. 1 MOBILIZATION AND DEMOBILIZATION 1 LS $17,000 $17,000 City Standard of 10% Estimate 2 MINOR CHANGES 1 FA $3,000 $3,000 Engineer Estimate 3 PROJECT TEMPORARY TRAFFIC CONTROL 1 LS $2,000 $2,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. Factored up by 50% for small project. 4 CONSTRUCTION SURVEYING, STAKING AND AS-BUILT DRAWINGS 1 LS $1,000 $1,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. Factored up by 50% for small project. 5 CONSTRUCTION TWPEC PLAN AND IMPLEMENTATION 1 LS $1,000 $1,000 Engineer Estimate 6 REMOVAL OF STRUCTURES AND OBSTRUCTIONS 1 LS $2,000 $2,000 Based on quanity breakdown of structures and unit price estimates 7 REMOVE AND REPLACE CONCRETE SIDEWALK AND DRIVEWAY 10 SY $108 $1,081 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 8 REMOVE AND REPLACE CONCRETE CURB AND GUTTER 20 LF $45 $890 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 9 CONTROL OF WATER (INCLUDES STORM DRAIN BYPASSES)1 LS $500 $500 Considered minor item as will be easy to bypass flow in existing system using plugs. 10 STORM DRAIN PIPE 12 INCH DIAMETER-CPEP 110 LF $80 $8,800 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 11 SELECT IMPORTED TRENCH BACKFILL 150 TN $50 $7,500 12 TYPE 1 CB 3 EA $1,800 $5,400 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. (Lid and rim offset by bird cage) 13 TYPE 2 MH 48"1 EA $5,000 $5,000 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 14 CONNECT EXISTING/NEW STORM PIPE TO EXISTING/NEW STORM STRUCTURE 1 EA $1,200 $1,200 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 15 DEWATERING 1 LS $1,000 $1,000 Engineer Estimate 16 TRENCH SAFETY SYSTEM 1 LS $1,000 $3,000 Reference: 2013 City of Renton/10th Street and Anacortes Detention Pond Retrofit (Added 18% inflation) 17 HMA CLASS 1/2" - 64-22 PAVEMENT PATCH 70 SY $37 $2,597 Reference: 2017 City of Renton/Renton Hills Storm Drain Bid Tab. 18 CRUSHED SURFACE BASE COURSE 9 TON $53 $467 Reference: 2013 City of Renton/10th Street and Anacortes Detention Pond Retrofit 19 CDF 2 CY $50 $100 SUBTOTAL SCHEDULE B $63,536 CONSTRUCTION CONTINGENCY 25%$25,414 SCHEDULE A CONSTRUCTION COST WITH CONTINGENCY $89,000 SALES TAX 0.0%$0 Assume 0% because of drainage associated with Roads TOTAL SCHEDULE B (TASK 1, 2 AND 3)$102,000 TOTAL PROJECT COST $409,000 1 Where a bid tab is referenced, the average of the 3 lowest bidders is used plus 3% inflation per year (unless otherwise noted). 2 Does not include pipe repair work at 3rd Place SE. Quantities are factored. GRANT REQUEST TOTAL ELIGIBLE AMOUNT (DOES NOT INCLUDE SCHEDULE B)$307,000 LESS FUNDING FROM KING COUNTY WATERWORKS GRANT -$70,000 REMAINING PROJECT COST $237,000 CITY MATCH AT 25%$59,250 TOTAL GRANT REQUEST $177,750 SCHEDULE B - PIPE REPLACEMENT WORK (NON-ELIGIBILE) TASK 3 - CONSTRUCTION Project Renton Hill Utility Replacement Project City of Renton Averages (3 lowest bidders)Laser Underground R.L. Alia Company SCI Infrastructure BID DATE:Sept. 26, 2017 Engineers Estimate And Earthwork Item No.Description Unit Quantity Unit Price Bid Amount Unit Price Bid Amount Unit Price Bid Amount Unit Price Bid Amount Unit Price Bid Amount Schedule A A01 Mobilization & Demobilization Lump Sum 1 130,000.00 130,000.00 $115,000 $115,000 $75,000.00 $75,000.00 $140,000.00 $140,000.00 $130,000.00 $130,000.00A02Trench Safety Systems Lump Sum 1 10,000.00 10,000.00 $15,833 $15,833 $30,000.00 $30,000.00 $10,000.00 $10,000.00 $7,500.00 $7,500.00A03Construction Surveying, Staking, and As-Built Drawings Lump Sum 1 7,500.00 7,500.00 $27,000 $27,000 $30,000.00 $30,000.00 $20,000.00 $20,000.00 $31,000.00 $31,000.00A04Temporary Traffic Control Lump Sum 1 10,000.00 10,000.00 $125,000 $125,000 $120,000.00 $120,000.00 $165,000.00 $165,000.00 $90,000.00 $90,000.00A05Stormwater Pollution Prevention and TESC Plan and Implementation Lump Sum 1 1,000.00 1,000.00 $10,667 $10,667 $20,000.00 $20,000.00 $10,000.00 $10,000.00 $2,000.00 $2,000.00A06Landscape Restoration Lump Sum 1 3,000.00 3,000.00 $24,000 $24,000 $20,000.00 $20,000.00 $40,000.00 $40,000.00 $12,000.00 $12,000.00A07Select Imported Trench Backfill Ton 5900 25.00 147,500.00 $20 $118,197 $20.00 $118,000.00 $0.10 $590.00 $40.00 $236,000.00A08Hot Mix Asphalt Patch Including CSTC for Storm Trench Sq. Yard 4600 50.00 230,000.00 $35 $161,000 $35.00 $161,000.00 $36.00 $165,600.00 $34.00 $156,400.00A09Remove and Replace Concrete Sidewalk and Driveway Sq. Yard 125 90.00 11,250.00 $102 $12,750 $125.00 $15,625.00 $66.00 $8,250.00 $115.00 $14,375.00A10Remove and Replace Concrete Curb and Gutter Linear Foot 575 25.00 14,375.00 $42 $23,958 $50.00 $28,750.00 $25.00 $14,375.00 $50.00 $28,750.00A11Replace Pavement Markings Lump Sum 1 2,000.00 2,000.00 $4,000 $4,000 $1,000.00 $1,000.00 $8,000.00 $8,000.00 $3,000.00 $3,000.00A12Removal and Replacement of Unsuitable Foundation Material Ton 150 35.00 5,250.00 $28 $4,250 $30.00 $4,500.00 $5.00 $750.00 $50.00 $7,500.00 A13 CCTV Inspection Linear Foot 4775 1.00 4,775.00 $5 $23,875 $4.00 $19,100.00 $7.00 $33,425.00 $4.00 $19,100.00A14Site Specific Utility Potholing Each 20 840.00 16,800.00 $433 $8,667 $500.00 $10,000.00 $500.00 $10,000.00 $300.00 $6,000.00 A15 Replace Survey Monument Each 4 940.00 3,760.00 $1,333 $5,333 $2,500.00 $10,000.00 $500.00 $2,000.00 $1,000.00 $4,000.00A16Stormwater Minor Changes Estimate 1 30,000.00 30,000.00 $30,000 $30,000 $30,000.00 $30,000.00 $30,000.00 $30,000.00 $30,000.00 $30,000.00 A17 Resolution of Utility Conflicts with Stormwater Force Account 1 20,000.00 20,000.00 $20,000 $20,000 $20,000.00 $20,000.00 $20,000.00 $20,000.00 $20,000.00 $20,000.00A18Construction Geotextile for Separation Sq. Yard 460 5.00 2,300.00 $3 $1,150 $1.00 $460.00 $5.00 $2,300.00 $1.50 $690.00A19Storm Drain, 6-inch Diameter (CPEP)Linear Foot 90 50.00 4,500.00 $77 $6,900 $100.00 $9,000.00 $80.00 $7,200.00 $50.00 $4,500.00A20Storm Drain, 8-inch Diameter (CPEP)Linear Foot 215 100.00 21,500.00 $77 $16,483 $100.00 $21,500.00 $80.00 $17,200.00 $50.00 $10,750.00A21Storm Drain, 8-inch Diameter (DI)Linear Foot 60 110.00 6,600.00 $93 $5,600 $110.00 $6,600.00 $100.00 $6,000.00 $70.00 $4,200.00A22Storm Drain, 12-inch Diameter (PPP)Linear Foot 4775 110.00 525,250.00 $74 $353,350 $75.00 $358,125.00 $80.00 $382,000.00 $67.00 $319,925.00A23Storm Drain, 12-inch Diameter (DI)Linear Foot 5 150.00 750.00 $400 $2,000 $200.00 $1,000.00 $500.00 $2,500.00 $500.00 $2,500.00A24Trench Drain Linear Foot 109 175.00 19,075.00 $367 $39,967 $450.00 $49,050.00 $300.00 $32,700.00 $350.00 $38,150.00A25Connect Existing Lateral to New Storm Pipe Each 5 500.00 2,500.00 $1,733 $8,667 $2,000.00 $10,000.00 $2,500.00 $12,500.00 $700.00 $3,500.00A26Connect New Storm Pipe to Existing Catch Basin Each 6 1,000.00 6,000.00 $2,000 $12,000 $3,000.00 $18,000.00 $2,500.00 $15,000.00 $500.00 $3,000.00A27Storm Lateral Cleanout - 6" or 8" Diameter Each 5 735.00 3,675.00 $1,133 $5,667 $800.00 $4,000.00 $2,000.00 $10,000.00 $600.00 $3,000.00A28Catch Basin Type 1 Each 44 1,600.00 70,400.00 $2,043 $89,907 $2,000.00 $88,000.00 $3,000.00 $132,000.00 $1,130.00 $49,720.00A29Catch Basin Type 1L With Special Frame and Grate Each 3 2,500.00 7,500.00 $2,183 $6,550 $2,200.00 $6,600.00 $3,000.00 $9,000.00 $1,350.00 $4,050.00A30Catch Basin Type 2, 48-inch Diameter Each 35 3,000.00 105,000.00 $4,350 $152,250 $4,500.00 $157,500.00 $6,000.00 $210,000.00 $2,550.00 $89,250.00A31Controlled Density Fill Cu. Yard 20 180.00 3,600.00 $150 $3,000 $100.00 $2,000.00 $200.00 $4,000.00 $150.00 $3,000.00A32Sewer Service Relocation for Stormwater Conflict Each 6 2,000.00 12,000.00 $2,667 $16,000 $500.00 $3,000.00 $4,000.00 $24,000.00 $3,500.00 $21,000.00A33Abandon Existing Manhole Each 2 500.00 1,000.00 $1,500 $3,000 $1,500.00 $3,000.00 $2,000.00 $4,000.00 $1,000.00 $2,000.00 Total A 1,438,860.00 $1,450,810.00 $1,450,810.00 $1,548,390.00 $1,356,860.00 Project: NE 10th Street and Anacortes Ave NE Detention Pond Rerofit Project CCT Construction, Inc.Green Earthworks Const.. Inc.A-1 Landscaping and Const.Weber Construction, Inc. Bid Date: July 16, 2013 Engineers Estimate Item Unit Est.Unit Bid Unit Bid Unit Bid Unit Bid Unit Bid Unit BidNo.Bid Item Description Quantity Price Amount Price Amount Price Amount Price Amount Price Amount Price Amount 1 Mobilization & Demobilization LS 1 20,000.00 20,000.00 19,255 19,255 12,000.00 12,000.00 27,766.00 27,766.00 18,000.00 18,000.00 14,000.00 14,000.00 2 Minor Changes LS 1 15,000.00 15,000.00 15,000 15,000 15,000.00 15,000.00 15,000.00 15,000.00 15,000.00 15,000.00 15,000.00 15,000.00 3 Construction Surveying, Staking and As-builtsLS 1 3,000.00 3,000.00 4,497 4,497 4,250.00 4,250.00 3,740.00 3,740.00 5,500.00 5,500.00 8,000.00 8,000.00 4 Traffic Control LS 1 3,000.00 3,000.00 4,278 4,278 3,000.00 3,000.00 935.00 935.00 8,900.00 8,900.00 5,000.00 5,000.00 5 Temporary Erosion/Sedimentation ControlsLS 1 5,000.00 5,000.00 3,741 3,741 800.00 800.00 623.00 623.00 9,800.00 9,800.00 6,500.00 6,500.00 6 Seeding, Fertilizing and Mulching SY 500 3.00 1,500.00 3 1,467 1.80 900.00 3.00 1,500.00 4.00 2,000.00 5.00 2,500.00 7 Final Cleanup and Restoration LS 1 5,000.00 5,000.00 8,534 8,534 10,000.00 10,000.00 2,202.00 2,202.00 13,400.00 13,400.00 8,000.00 8,000.00 8 Clearing and Grubbing LS 1 5,000.00 5,000.00 5,635 5,635 4,000.00 4,000.00 6,405.00 6,405.00 6,500.00 6,500.00 7,000.00 7,000.00 9 Removal of Structures and Obstructions LS 1 5,000.00 5,000.00 7,804 7,804 6,500.00 6,500.00 5,912.00 5,912.00 11,000.00 11,000.00 5,000.00 5,000.00 10 Pond Excavation, Incl. Haul CY 1,500 30.00 45,000.00 27 40,365 25.00 37,500.00 34.73 52,095.00 21.00 31,500.00 24.00 36,000.00 11 Crushed Surfacing Base Course TN 35 50.00 1,750.00 45 1,575 50.00 1,750.00 53.00 1,855.00 32.00 1,120.00 40.00 1,400.00 12 Quarry Spalls TN 90 50.00 4,500.00 45 4,020 60.00 5,400.00 39.00 3,510.00 35.00 3,150.00 40.00 3,600.00 13 Furnish and Install 18-inch CPEP Storm PipeLF 215 100.00 21,500.00 55 11,753 50.00 10,750.00 54.00 11,610.00 60.00 12,900.00 35.00 7,525.00 14 Removal and Replacement of Unsuitable Foundation MaterialTN20 25.00 500.00 40 807 20.00 400.00 69.00 1,380.00 32.00 640.00 100.00 2,000.00 15 Selected Imported Trench Backfill TN 280 20.00 5,600.00 21 5,927 20.00 5,600.00 15.50 4,340.00 28.00 7,840.00 40.00 11,200.00 16 Furnish and Install Type II Catch Basin - 48" Dia.EA 1 2,500.00 2,500.00 5,682 5,682 4,800.00 4,800.00 5,347.00 5,347.00 6,900.00 6,900.00 3,300.00 3,300.00 17 Connect New Storm Sewer to Existing StructureEA 1 2,500.00 2,500.00 1,473 1,473 1,000.00 1,000.00 2,870.00 2,870.00 550.00 550.00 3,000.00 3,000.00 18 Trench Excavation Safety Systems LS 1 2,500.00 2,500.00 2,475 2,475 5,000.00 5,000.00 624.00 624.00 1,800.00 1,800.00 4,500.00 4,500.00 19 Temporary Dewatering LS 1 6,500.00 6,500.00 2,358 2,358 1,200.00 1,200.00 2,675.00 2,675.00 3,200.00 3,200.00 12,000.00 12,000.00 20 Erosion Control Blanket SY 1,100 5.00 5,500.00 2 2,640 2.00 2,200.00 0.70 770.00 4.50 4,950.00 7.00 7,700.00 21 Topsoil Type C CY 20 30.00 600.00 48 960 60.00 1,200.00 52.00 1,040.00 32.00 640.00 75.00 1,500.00 22 Post CPEP Installation Inspection LF 215 4.00 860.00 8 1,648 9.00 1,935.00 10.00 2,150.00 4.00 860.00 9.50 2,042.50 0 0 Sales Tax Rule 171 Applies (tax to be included within bid item price)Subtotal $162,310.00 Subtotal $151,894.67 Subtotal $135,185.00 Subtotal $154,349.00 Subtotal $166,150.00 Subtotal $166,767.50 By:Total $162,310.00 Total $151,894.67 Total $135,185.00 Total $154,349.00 Total $166,150.00 Total $166,767.50 Ave of 3 Lowest Bidders Reference Cost Est. Renton 10th Detenion Pond Retrofit Page 1 Project:2019StormwaterFacilityFencingProjectBidDate:February6,2019ItemUnitBst.No.BidItemDescriotionQuantityEngineersEstimateK-AGeneralConstructionContractorLLCUnitBidUnitBidPriceAmountPriceAmountCommercialFencingCorporationUnitBidPriceAmount2345678910111213141516171819RWSConstructionLLCmonaorionanascapinganeServicesLLCUnitBidUnitBidPriceAmountPriceAmountMinorChangesEot.DonstructionSurve1ng,Staking,andAs-BuiltoLSMobilization(maynotbemorethan10%ottotalBidLSRemovalotStructuresandObstructionsLSMaureenHighlandDivision1Pond-BlackChainU’LFHoneyCreekRidgePond-BlackCheinLinkFenceLFMorningGlenPond-BlackChainUnkFenceLFChinquapinRidgePond-BluckChainUnkFenceLFKimbedyLanePond-BlackChainUnkFenceLFSpdegbrookTemacePond-BlackChainLinkFenciLFMaureenHighlandDivision1Pond-Black16-FootBAHoneyCreekRidgePond-Black16-FootChumLinEAMorningGlenPond-Black16-FootChainLinkGabBAChinquapinRidgePond-Black16-FootChainUnkEAKimberlyLanePond-Black16-FootChainLinkGalEASpringbrookTemacaPond-Black16FootChainUiBAHoneyCreakRidgePond-Black8-FootChainLinkBAChinquapinRidgePond-Black4-FootChainLinkCBASpringbrookTerracePond-Black8-FootChainLirEA65973847259223333518,000.009,900.0016,200.007,100.0046.0046.0046.0046.0046.0046.003,888.003,888.003,888.003,888.003,888.003,888.001,944.00972.001,944.0018,000.009,900.0016,200.007,100.0030,314.0033,948.0021,712.0027,232.0010,718.0015,410.003,888.003,888.003,888.003,888.003,888.003,888.001,944.00972.001,944.0018,000.003,000.0015,000.005,282.3636.7536.7536.7536.7536.7536.751,000.001,000.001,000.001,000.001,000.001,000.00500.00400.00500.0018,000.003,000.0015,000.005,282.3624,218.2527,121.5017,346.0021,756.008,562.7512,311.251,000.001,000.001,000.001,000.001,000.001,000.00500.00400.00500.0018,000.0031,372.00500.007,500.0031.3835.2536.9231.5237.1647.38800.00800.00800.00800.00800.00800.00450.00250.00450.0018,000.0031,372.00500.007,500.0020,679.4226,014.5017,426.2418,659.848,658.2815,872.30800.00800.00800.00800.00800.00800.00450.00250.00450.0018,000.0013,682.0015,200.0017,171.3239.4739.3444.3639.8056.9251.251,955.701,955.701,955.701,955.701,955.701,955.701,050.40960.471,050.4018,000.0013,682.0015,200.0017,171.3226,010.7329,032.9220,937.9223,561.6013,262.3617,168.751,955.701,955.701,955.701,955.701,955.701,955.701,050,40960.471,050,4018,000.0018,000.005,000.005,000.004,000.004,000.0015,000.0015,000.0037.1124,455.4936.0326,590.1441.1219,408.6438.1622,590.7255.7512,989.7547.0015,745.005,540.005,540.005,540.005,540,005,540.005,540.005,540.005,540.005,540.005,540,005,540.005,540.005,500.005,500.005,900.005,900.006,000.006,000.00SalesTanRule170Applies(lastobenotincludedwithinbiditemprice(SaleTan(10.0%(By:kC74..J)1’)‘°‘NKenSniotung,ProjectManagerC..•1Subtotal$218,722.00Subtotal$159,998.11$170,632.58Subtotal$208,823.07Subtotal$214,419.74$21,872.20$15,999.81$17,063.26$20,882.31$21,441.97Total$240,594.20Total$175,997.92$187,695.84Total$229,705.38Total$235,861.71BidTab-FencingPage1 Project: SW 7th Street, Powell Ave SW to Lind Ave SW, Storm System Improv. Project - Phase 2 - SWP-27-3570 STATISTICAL SUMMARY Bid Date: May 17, 2016 Engineers Estimate Rodarte Construction, Inc.Scarsella Bros. Inc.R. L. Alia Company Average ThreeItemUnitEst.Unit Bid Unit Bid Unit Bid Unit Bid Lowest BidsNo.Description: Quantity Price Amount Price Amount Price Amount Price Amount Unit Price 1 Mobilization and Demobilization (may not be more than 10% of total bid)LS 1 240,000.00 240,000.00 261,000.00 261,000.00 315,000.00 315,000.00 170,000.00 170,000.00 248,666.67 2 Minor Changes Est.1 70,000.00 70,000.00 70,000.00 70,000.00 70,000.00 70,000.00 70,000.00 70,000.00 70,000.00 3 Construction Surveying, Staking and As-built DrawingsLS 1 12,000.00 12,000.00 13,000.00 13,000.00 20,000.00 20,000.00 5,000.00 5,000.00 12,666.67 4 Replace Survey Monument EA 6 650.00 3,900.00 600.00 3,600.00 600.00 3,600.00 1,500.00 9,000.00 900.00 5 Archeological and Historical Salvage EST 1 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 6 Utility potholing EA 15 650.00 9,750.00 550.00 8,250.00 500.00 7,500.00 350.00 5,250.00 466.67 7 Resolution of Utility Conflicts FA 1 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 8 Resolution of Verizon Utility Conflict FA 1 5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 9 Stormwater Pollution Prevention and TESC Plan and ImplementationLS1 3,000.00 3,000.00 1,000.00 1,000.00 90,000.00 90,000.00 5,000.00 5,000.00 32,000.00 10 Inlet Protection EA 14 80.00 1,120.00 55.00 770.00 125.00 1,750.00 100.00 1,400.00 93.33 11 Temporary Traffic Control LS 1 145,000.00 145,000.00 112,000.00 112,000.00 200,000.00 200,000.00 100,000.00 100,000.00 137,333.33 12 Removal of Structures and Obstructions LS 1 12,000.00 12,000.00 1,500.00 1,500.00 30,000.00 30,000.00 10,000.00 10,000.00 13,833.33 13 Construction Support and BNSF Coordination for Railroad Track Removal and ReplacementLS150,000.00 50,000.00 15,000.00 15,000.00 40,000.00 40,000.00 8,000.00 8,000.00 21,000.00 14 Contaminated Soil and Water Management Plan LS 1 3,000.00 3,000.00 2,500.00 2,500.00 5,000.00 5,000.00 5,000.00 5,000.00 4,166.67 15 Soil Compaction Testing EA 15 525.00 7,875.00 130.00 1,950.00 200.00 3,000.00 500.00 7,500.00 276.67 16 Soil Sampling and Testing EA 3 600.00 1,800.00 250.00 750.00 1,500.00 4,500.00 2,000.00 6,000.00 1,250.00 17 Contaminated Soil Excavation, Inc. Haul FA 1 30,000.00 30,000.00 30,000.00 30,000.00 30,000.00 30,000.00 30,000.00 30,000.00 30,000.00 18 Contaminated water treatment FA 1 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 20,000.00 19 Dewatering LS 1 250,000.00 250,000.00 175,000.00 175,000.00 170,000.00 170,000.00 95,000.00 95,000.00 146,666.67 20 Shoring and Extra Excavation, Class B LS 1 68,000.00 68,000.00 4,000.00 4,000.00 2,000.00 2,000.00 5,000.00 5,000.00 3,666.67 21 Structure Excavation, Incl. Haul LS 1 3,500.00 3,500.00 8,000.00 8,000.00 2,500.00 2,500.00 50,000.00 50,000.00 20,166.67 22 Trench Safety Systems LS 1 16,000.00 16,000.00 2,500.00 2,500.00 18,000.00 18,000.00 25,000.00 25,000.00 15,166.67 23 Control of Water (includes storm drain bypasses)LS 1 30,000.00 30,000.00 22,000.00 22,000.00 5,000.00 5,000.00 16,000.00 16,000.00 14,333.33 24 Sawcutting LF 4,500 5.00 22,500.00 3.00 13,500.00 2.25 10,125.00 7.00 31,500.00 4.08 25 Remove Asphalt, Full Depth for Trenching SY 3,500 20.00 70,000.00 8.00 28,000.00 5.00 17,500.00 5.00 17,500.00 6.00 26 Remove Asphalt, 2-in Grind for Overlay SY 8,100 10.00 81,000.00 5.50 44,550.00 2.00 16,200.00 3.00 24,300.00 3.50 27 Crushed Surfacing Top Course TON 1,100 38.00 41,800.00 30.00 33,000.00 35.00 38,500.00 30.00 33,000.00 31.67 28 HMA Class 1/2" 64-22 TON 2,900 130.00 377,000.00 95.00 275,500.00 78.50 227,650.00 135.00 391,500.00 102.83 29 Temporary Cold Mix Asphalt Concrete Patch TON 150 130.00 19,500.00 130.00 19,500.00 150.00 22,500.00 150.00 22,500.00 143.33 30 Removal and Replacement of Unsuitable Foundation Excavation Incl. Haul CY 170 47.00 7,990.00 60.00 10,200.00 35.00 5,950.00 50.00 8,500.00 48.33 31 Construction Geotextile for Separation SY 1,200 4.00 4,800.00 3.00 3,600.00 2.50 3,000.00 10.00 12,000.00 5.17 32 8'-0" L x 8'-6" W x 9'-0" H Stormwater Vault (MH6)LS 1 75,000.00 75,000.00 28,500.00 28,500.00 30,500.00 30,500.00 56,000.00 56,000.00 38,333.33 33 15'-6" L x 8'-6" W x 9'-0" H Stormwater Vault (MH9)LS 1 102,000.00 102,000.00 51,000.00 51,000.00 51,000.00 51,000.00 56,000.00 56,000.00 52,666.67 34 Storm Drain, 8-inch Diameter - CPEP LF 43 80.00 3,440.00 124.00 5,332.00 75.00 3,225.00 175.00 7,525.00 124.67 35 Storm Drain, 12-inch Diameter - CPEP LF 88 90.00 7,920.00 140.00 12,320.00 84.00 7,392.00 200.00 17,600.00 141.33 36 Storm Drain, 36-inch Diameter Grade A36 Steel PipeLF 170 315.00 53,550.00 700.00 119,000.00 610.00 103,700.00 600.00 102,000.00 636.67 37 Storm Drain, 36-inch Diameter Grade 50 Steel Pipe LF 162 370.00 59,940.00 700.00 113,400.00 625.00 101,250.00 600.00 97,200.00 641.67 38 Storm Drain, 36-inch Diameter Polypropylene LF 94 250.00 23,500.00 365.00 34,310.00 305.00 28,670.00 600.00 56,400.00 423.33 39 Storm Drain, 60-inch Diameter Polypropylene LF 1,674 380.00 636,120.00 525.00 878,850.00 420.00 703,080.00 600.00 1,004,400.00 515.00 40 Storm Drain, 60-inch Diameter Grade 50 Steel Pipe LF 140 595.00 83,300.00 1,100.00 154,000.00 1,400.00 196,000.00 600.00 84,000.00 1,033.33 41 Coredrill Pipe and Connect Storm EA 12 2,000.00 24,000.00 3,000.00 36,000.00 2,200.00 26,400.00 5,000.00 60,000.00 3,400.00 42 Coredrill Steel Pipe and Connect Storm EA 1 5,250.00 5,250.00 5,000.00 5,000.00 3,200.00 3,200.00 10,000.00 10,000.00 6,066.67 43 Television inspection LF 2,240 3.00 6,720.00 3.00 6,720.00 5.00 11,200.00 12.00 26,880.00 6.67 44 Select Imported Trench Backfill TON 4,700 28.00 131,600.00 22.00 103,400.00 16.50 77,550.00 2.00 9,400.00 13.50 45 Pervious Backfill Material TON 150 35.00 5,250.00 32.00 4,800.00 35.00 5,250.00 50.00 7,500.00 39.00 46 Subballast TON 160 40.00 6,400.00 42.00 6,720.00 35.00 5,600.00 50.00 8,000.00 42.33 47 Catch Basin Type 1 EA 6 1,400.00 8,400.00 1,500.00 9,000.00 1,625.00 9,750.00 2,000.00 12,000.00 1,708.33 48 Concrete Inlet EA 2 1,200.00 2,400.00 1,800.00 3,600.00 1,450.00 2,900.00 1,000.00 2,000.00 1,416.67 49 Manhole Type 3 - 96-inch Diameter EA 8 15,800.00 126,400.00 12,000.00 96,000.00 16,850.00 134,800.00 18,000.00 144,000.00 15,616.67 50 Manhole Type 3 - 120-inch Diameter EA 4 21,000.00 84,000.00 25,000.00 100,000.00 23,820.00 95,280.00 25,000.00 100,000.00 24,606.67 51 Connect new 60-inch storm pipe to Existing Storm ManholeEA 1 2,650.00 2,650.00 7,500.00 7,500.00 7,000.00 7,000.00 20,000.00 20,000.00 11,500.00 52 Coredrill and Connect New Dual 36-inch Pipe to Existing VaultEA 1 5,000.00 5,000.00 5,000.00 5,000.00 10,000.00 10,000.00 15,000.00 15,000.00 10,000.00 53 Connect existing pipe to New structure EA 3 2,200.00 6,600.00 2,500.00 7,500.00 3,000.00 9,000.00 2,000.00 6,000.00 2,500.00 54 Sanitary Sewer Manhole Type 3 - 60-inch Diameter EA 2 6,300.00 12,600.00 3,250.00 6,500.00 7,800.00 15,600.00 15,000.00 30,000.00 8,683.33 55 Connect existing sanitary pipe to New structure EA 2 2,650.00 5,300.00 1,750.00 3,500.00 2,250.00 4,500.00 5,000.00 10,000.00 3,000.00 56 PVC Sanitary Sewer Pipe - 8-in Diameter LF 32 170.00 5,440.00 92.00 2,944.00 80.00 2,560.00 250.00 8,000.00 140.67 57 Steel Casing Pipe For Sewer Main, 14-inch DiameterEA 2 6,300.00 12,600.00 1,800.00 3,600.00 4,950.00 9,900.00 8,000.00 16,000.00 4,916.67 Referecne BidTab-03 SW7th-wBidders-FINAL-wStats Page 1 Project: SW 7th Street, Powell Ave SW to Lind Ave SW, Storm System Improv. Project - Phase 2 - SWP-27-3570 STATISTICAL SUMMARY Bid Date: May 17, 2016 Engineers Estimate Rodarte Construction, Inc.Scarsella Bros. Inc.R. L. Alia Company Average ThreeItemUnitEst.Unit Bid Unit Bid Unit Bid Unit Bid Lowest BidsNo.Description: Quantity Price Amount Price Amount Price Amount Price Amount Unit Price 58 Temporay Sewer Bypass Systems LS 1 6,000.00 6,000.00 2,500.00 2,500.00 7,500.00 7,500.00 5,800.00 5,800.00 5,266.67 59 Decomissioning Well EA 1 2,000.00 2,000.00 5,000.00 5,000.00 3,500.00 3,500.00 1,200.00 1,200.00 3,233.33 60 Controlled Density Fill CY 50 180.00 9,000.00 115.00 5,750.00 150.00 7,500.00 150.00 7,500.00 138.33 61 Connection to Existing Water Main, 10-inch DiameterEA 1 3,150.00 3,150.00 3,500.00 3,500.00 2,705.00 2,705.00 3,000.00 3,000.00 3,068.33 62 Connection to Existing Water Main, 12-inch DiameterEA 3 3,700.00 11,100.00 3,500.00 10,500.00 2,705.00 8,115.00 3,000.00 9,000.00 3,068.33 63 Concrete for Thrust Blocking CY 10 400.00 4,000.00 300.00 3,000.00 250.00 2,500.00 200.00 2,000.00 250.00 64 Reinforced Concrete For Water Line Cover ProtectionSY 8 315.00 2,520.00 200.00 1,600.00 300.00 2,400.00 150.00 1,200.00 216.67 65 Furnish and Install 10-inch Dia. Cl 52 DI Water Pipe & Fittings LF 40 325.00 13,000.00 125.00 5,000.00 230.00 9,200.00 350.00 14,000.00 235.00 66 Furnish and Install 12-inch Dia. Cl 52 DI Water Pipe & Fittings LF 42 400.00 16,800.00 155.00 6,510.00 270.00 11,340.00 350.00 14,700.00 258.33 67 Furnish and Install 10-inch Dia. Gate Valve Assembly EA 1 2,800.00 2,800.00 1,000.00 1,000.00 7,500.00 7,500.00 2,000.00 2,000.00 3,500.00 68 Furnish and Install 12-inch Dia. Gate Valve Assembly EA 1 3,700.00 3,700.00 3,250.00 3,250.00 3,500.00 3,500.00 2,000.00 2,000.00 2,916.67 69 Remove and Replace Cement Concrete Curb and GutterLF 70 40.00 2,800.00 70.00 4,900.00 70.00 4,900.00 40.00 2,800.00 60.00 70 Remove and Replace Cement Concrete Sidewalk and DrivewaySY50 60.00 3,000.00 140.00 7,000.00 100.00 5,000.00 60.00 3,000.00 100.00 71 Restore Pavement Markings LS 1 12,000.00 12,000.00 10,000.00 10,000.00 17,000.00 17,000.00 15,000.00 15,000.00 14,000.00 By: Daniel Carey Total Bid =$3,233,785.00 Total Bid =$3,099,676.00 Total Bid =$3,172,242.00 Total Bid =$3,278,055.00 3,183,324.33 City of Renton, Surface Water Utility Referecne BidTab-03 SW7th-wBidders-FINAL-wStats Page 2 APPENDIX This page left intentionally blank. APPENDIX C-3 FINAL COST ESTIMATE SCHEDULES A AND B APPENDIX This page left intentionally blank. Number Bid Item Description Unit Quantity (City)Unit Cost Engineer Est A1 MOBILIZATION LS 1 17,000$ $17,000.00 A2 MINOR CHANGES FA EST.$15,000 $15,000.00 A3 PROJECT TEMPORARY TRAFFIC CONTROL LS 1 $7,000 $7,000.00 A4 CONSTRUCTION SURVEYING, STAKING AND AS-BUILTS LS 1 $6,000 $6,000.00 A5 SITE POTHOLES EA 2 $1,200 $2,400.00 A6 TEMPORARY WATER POLLUTION PREVENTION LS 1 $12,000 $12,000.00 A7 REMOVAL OF STRUCTURES AND OBSTRUCTIONS LS 1 $5,000 $5,000.00 A8 REMOVE AND REPLACE CONCRETE SIDEWALK SY 7 $110.00 $770.00 A9 REMOVE AND REPLACE CONCRETE CURB AND GUTTER LF 12 $45 $534.24 A10 CONTROL OF WATER (INCLUDES STORM DRAIN BYPASSES)LS 1 $3,000 $3,000.00 A11 STORM DRAIN PIPE 18 INCH DIAMETER-CPEP LF 50 $100.00 $5,000.00 A12 STORM DRAIN PIPE 24 INCH DIAMETER-CPEP LF 15 $140 $2,100.00 A13 SELECT IMPORTED TRENCH BACKFILL TN 30 $50 $1,500.00 A14 EXISTING TYPE 2 CATCH BASIN #2165 MODIFICATIONS EA 1 $2,000 $2,000.00 A15 TYPE 2 CB 54-INCH DIAMETER WITH OVERFLOW STRUCTURE EA 1 $5,000 $5,000.00 A16 TYPE 2 CATCH BASIN 48" DIAMETER EA 1 $5,000 $5,000.00 A17 TYPE 2 CB 54-INCH DIAMETER CONTROL STRUCTURE EA 1 $7,000 $7,000.00 A18 CONNECT TO EXISTING STORM STRUCTURE EA 3 $1,200.00 $3,600.00 A19 DEWATERING LS 1 $15,000 $15,000.00 A20 POND EXCAVATION INCL. HAUL AND DISPOSAL LS 1 $25,000 $25,000.00 A21 TRENCH SAFETY SYSTEMS LS 1 $2,000 $2,000.00 A22 REMOVAL AND REPLACEMENT OF 6-FT CHAIN LINK FENCE LF 360 $50 $18,000.00 A23 REMOVAL AND REPLACEMENT OF 6-FT HIGH CHAIN LINK GATE EA 2 $2,000 $4,000.00 A24 HMA CLASS 1/2" - 64-22 TON 2 $175 $350.00 A25 TEMPORARY COLD MIX ASPHALT CONCRETE PATCH TON 1 $175 $175.00 A26 REVEGETATION WITH HYDROSEED LS 1 $1,800 $1,800.00 A27 POND ACCESS ROAD SY 95 $60 $5,700.00 A28 CONTROL DENSITY FILL CY 5 $175 $875.00 A29 DECOMMISSIONING EXISTING MONITORING WELL EA 1 $3,488 $3,488.00 A30 COMPOST AMEMDED SOIL SY 250 $10 $2,500.00 A31 PSIPE - JUNCUS EFFUSUS EA 300 $10 $3,000.00 A32 PSIPE - SCIRPUS ACUTUS EA 300 $10 $3,000.00 A33 PSIPE - SCIRPUS MICROSCARPUS EA 300 $10 $3,000.00 A34 LOW PERMEABLE LINER MATERIAL CY 130 $35 $4,550.00 A35 PROJECT SIGN LS 1 $1,500 $1,500.00 B1 MOBILIZATION LS 1 $10,000 $10,000.00 B2 MINOR CHANGES FA EST.$4,000 $4,000.00 B3 PROJECT TEMPORARY TRAFFIC CONTROL LS 1 $2,000 $2,000.00 B4 CONSTRUCTION SURVEYING, STAKING AND AS-BUILTS LS 1 $1,000 $1,000.00 B5 TEMPORARY WATER POLLUTION PREVENTION LS 1 $1,000 $1,000.00 B6 REMOVAL OF STRUCTURES AND OBSTRUCTIONS LS 1 $2,000 $2,000.00 B7 REMOVE AND REPLACE CONCRETE SIDEWALK SY 6 108.12$ $648.72 B8 REMOVE AND REPLACE CONCRETE CURB AND GUTTER LF 25 $45 $1,113.00 B9 CONTROL OF WATER (INCLUDES STORM DRAIN BYPASSES)LS 1 $500 $500.00 B10 STORM DRAIN PIPE 12 INCH DIAMETER - CONCRETE LF 15 $120 $1,800.00 B11 STORM DRAIN PIPE 12 INCH DIAMETER - DI LF 100 $170 $17,000.00 B12 SELECT IMPORTED TRENCH BACKFILL TN 150 $50 $7,500.00 B13 TYPE 1 CATCH BASIN EA 4 $1,800 $7,200.00 B14 CONNECT TO EXISTING STORM STRUCTURE EA 1 $1,200 $1,200.00 B15 DEWATERING LS 1 $2,000 $2,000.00 B16 TRENCH SAFETY SYSTEM LS 1 $1,000 $1,000.00 B17 HMA CLASS 1/2" - 64-22 TON 60 $175 $10,500.00 B18 TEMPORARY COLD MIX ASPHALT CONCRETE PATCH TON 9 $175 $1,575.00 B19 CDF CY 5 $175 $875.00 B20 CCTV NEW STORM DRAIN PIPE LF 115 $8 $920.00 $0.00 $267,673.96 State Tax Rule 170 Applies - Sales tax will be added to the full Contract price.0%Sales Tax = $0.00 Total = $267,673.96 City of Renton Heather Downs Water Quality Retrofit ProjectFinal Cost Estimate(June 10, 2020) Cost Est and Bid Tab- Heather Downs - 06-10-20.xlsDATA & COST EST PAGE PAGE) APPENDIX This page left intentionally blank. APPENDIX D FINAL DESIGN APPENDIX This page left intentionally blank. COVER SHEETNLOCATION MAPHEATHER DOWNS DETENTION PONDWATER QUALITY RETROFIT PROJECTPlanning/Building/Public Works Dept.CITY OFRENTON999 Third Avenue, Ste 3200Seattle, WA 98104 ·206.382.5200HEATHER DOWNS DETENTION POND WATERQUALITY RETROFIT PROJECTMICHAEL S. GISEBURTPROFESSIONAL ENGINEERREGISTERED STATE OF WASHINGTONSWP - 27 - 3989 SWP-3989NVICINITY MAPBYAPPROVED FOR CONSTRUCTIONBYDATESHEET INDEXSHEET NO.DWG NO.SHEET TITLEUTILITY CONTACTSWATER:CITY OF RENTON(425) 430-7400andSEATTLE PUBLIC UTILITIES(206) 953-0184SANITARY SEWER:CITY OF RENTON(425) 430-7400CABLE:COMCAST(206) 391-1763 or (253) 686-2592and/orCENTURYLINK(206) 733-8866 or (206) 733-8857POWER:PUGET SOUND ENERGY(425) 559-4647 KEN SRILOFUNG This page left intentionally blank. NOTES & ABBREVIATIONS ” Planning/Building/Public Works Dept. CITY OF RENTON 999 Third Avenue, Ste 3200 Seattle, WA 98104 · 206.382.5200 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECTMICHAEL S. GIS E BURTPROF E SSIONAL E N G IN E ERREGISTERE DSTATE O F WASHI N GTONSWP - 27 - 3989S W P -3 9 8 9 DETAILSECTION This page left intentionally blank. 2048 SDMH 2048 RIM=374.09 IE 12" CMP SW=369.69 IE 12" CMP S=368.49 IE 12" CONC N=368.06 ABANDONED IE 12" CONC E=367.79 2165 24" CMP W/DEBRIS CAGE IE=368.22 2049 SDMH 2049 RIM=374.01 IE 12" PVC NW=367.66 IE 12" CONC E-W=367.58 SDMH 2165 RIM=375.31 TOP 12" VERT CMP O/F SE=373.61 IE=368.01 IE 8" PVC SW=371.61 IE 24" CONC NW=368.01 IE 24" CMP NE=368.01 2047 2045 SDCB 2045 TYPE I RIM=373.96 IE 15" CMP E=370.30 2169 SDCB 2047 TYPE I RIM=373.72 IE 8" CMP NE=372.02 2002 SDCB 2002 TYPE I STRUCTURE ROTATION RIM=373.47 IE 12" CMP N=370.34 IE 12" CMP NE=370.15 102 200 101 SDCB 2169 TYPE I RIM=373.64 IE 12" CMP N=370.79 CONC WALKCONC WALKROOTS RAISING CONC WALK2-8", 1-10", 2-12"CEDAR CLUSTER1-8", 2-6", 1-16"CEDAR CLUSTER"NO PARKINGHERE TO CORNER"24"1-12", 1-24" CEDAR12" STUMPGROUND=374.8'TOP=376.4'8"STUMPGROUND=374.7'TOP=375.0'24" STUMP GROUND=375.7 TOP=377.1' 30" STUMP GROUND=376.9 TOP=378.1'36" STUMPGROUND=377.4'TOP=379.4'36" STUMPGROUND=376.5'TOP=377.7'WV LID=373.87' TOP NUT=372.77'WV LID=373.46' TOP NUT=370.76' WMH LID=373.96' TOP OF NUT=371.46' TOP OF PIPE TO N=369.46' DOUBLE 6' CLF SWING GATEDOUBLE 6' CLFSWING GATE6' CLF "STOP" DOUBLE YELLOW RAISED LANE MARKERSYELLOW SKIP RAISED LANE MARKERSPONDDWY FND 5/8" REBAR, NO CAP W/WHITE CAP, "B&F INC 12870 & 129XX" (ILLEGIBLE) FND 5/8" REBAR, NO CAP 2046 STOP BARTOP CENTER 0.45' TALL RR TIES SHED LEAN TO 6' CLF GATE 6' BOARD FENCE TOP CENTER 0.3' TALL CONC WALL SSMH 2289 RIM=374.24 CTR CHANNEL N,E,S=359.59 2289 370370375374 374 37337537536936937437637 7 374374374SDMH 2046 RIM=374.48 IE 15" CMP W=369.43 IE 12" CMP N=368.13 IE 24" CONC SE=368.03 Planning/Building/Public Works Dept. CITY OF RENTON 999 Third Avenue, Ste 3200 Seattle, WA 98104 · 206.382.5200 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECTMICHAEL S. GIS E BURTPROF E SSIONAL E N G IN E ERREGISTERE DSTATE O F WASHI N GTONSWP - 27 - 3989S W P -3 9 8 9 TESC PLAN N PLAN This page left intentionally blank. 2048 SDMH 2048 RIM=374.09 IE 12" CMP SW=369.69 IE 12" CMP S=368.49 IE 12" CONC N=368.06 ABANDONED IE 12" CONC E=367.79 2165 24" CMP W/DEBRIS CAGE IE=368.22 2049 SDMH 2049 RIM=374.01 IE 12" PVC NW=367.66 IE 12" CONC E-W=367.58 SDMH 2165 RIM=375.31 TOP 12" VERT CMP O/F SE=373.61 IE=368.01 IE 8" PVC SW=371.61 IE 24" CONC NW=368.01 IE 24" CMP NE=368.01 2047 2045 SDCB 2045 TYPE I RIM=373.96 IE 15" CMP E=370.30 2169 SDCB 2047 TYPE I RIM=373.72 IE 8" CMP NE=372.02 2002 SDCB 2002 TYPE I STRUCTURE ROTATION RIM=373.47 IE 12" CMP N=370.34 IE 12" CMP NE=370.15 102 200 101 SDCB 2169 TYPE I RIM=373.64 IE 12" CMP N=370.79 CONC WALKCONC WALKROOTS RAISING CONC WALK2-8", 1-10", 2-12"CEDAR CLUSTER1-8", 2-6", 1-16"CEDAR CLUSTER"NO PARKINGHERE TO CORNER"24"1-12", 1-24" CEDAR12" STUMPGROUND=374.8'TOP=376.4'8"STUMPGROUND=374.7'TOP=375.0'24" STUMP GROUND=375.7 TOP=377.1' 30" STUMP GROUND=376.9 TOP=378.1'36" STUMPGROUND=377.4'TOP=379.4'36" STUMPGROUND=376.5'TOP=377.7'WV LID=373.87' TOP NUT=372.77'WV LID=373.46' TOP NUT=370.76' WMH LID=373.96' TOP OF NUT=371.46' TOP OF PIPE TO N=369.46' DOUBLE 6' CLF SWING GATEDOUBLE 6' CLFSWING GATE6' CLF "STOP" DOUBLE YELLOW RAISED LANE MARKERSYELLOW SKIP RAISED LANE MARKERSPONDDWY FND 5/8" REBAR, NO CAP FND 1/2" REBAR W/WHITE CAP, "B&F INC 12870 & 129XX" (ILLEGIBLE) FND 5/8" REBAR, NO CAP 2046 STOP BARTOP CENTER 0.45' TALL RR TIES SHED LEAN TO 6' CLF GATE 6' BOARD FENCE TOP CENTER 0.3' TALL CONC WALL SSMH 2289 RIM=374.24 CTR CHANNEL N,E,S=359.59 2289 370370375374 374 37337537536936937437637 7 374374374SDMH 2046 RIM=374.48 IE 15" CMP W=369.43 IE 12" CMP N=368.13 IE 24" CONC SE=368.03 CONSTRUCTION NOTES Planning/Building/Public Works Dept. CITY OF RENTON 999 Third Avenue, Ste 3200 Seattle, WA 98104 · 206.382.5200 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECTMICHAEL S. GIS E B URTPROF ESSIONAL E N G IN EERREGISTERE DSTATE O F WASHI N GTONSWP - 27 - 3989S W P -3 9 8 9 SITE PLAN - HEATHER DOWNS N PLAN POINT NO.NORTHING EASTING ELEVATIONDESCRIPTION 1 177580.1111311394.612 365.00 INLET PIPE 2 177579.6331311410.119 365.00 POND BOTTOM 3 177567.8491311409.151 365.00 POND BOTTOM 4 177509.4511311411.466 365.00 POND BOTTOM 5 177510.4591311385.012 365.00 POND BOTTOM 6 177515.4371311384.944 365.00 POND BOTTOM 7 177517.4431311393.652 365.00 POND BOTTOM / ACCESS ROAD 8 177534.6461311403.308 365.00 POND BOTTOM / ACCESS ROAD 9 177553.3581311402.970 365.00 POND BOTTOM 10 177568.2871311400.268 365.00 POND BOTTOM 11 177589.3021311378.558 369.00 POND LINER 12 177586.0171311418.820 369.00 POND LINER 13 177502.3541311419.848 369.00 POND LINER 14 177503.8231311376.923 369.00 POND LINER 15 177530.1901311378.254 369.00 POND LINER 16 177555.2011311392.867 369.00 POND LINER 17 177554.0971311375.087 371.50 ACCESS ROAD 18 177565.1921311385.686 370.50 ACCESS ROAD 19 177502.1541311377.724 368.14 OUTLET PIPE SYMBOL LEGEND This page left intentionally blank. DETAIL CONSTRUCTION NOTES SECTION Planning/Building/Public Works Dept. CITY OF RENTON 999 Third Avenue, Ste 3200 Seattle, WA 98104 · 206.382.5200 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECTMICHAEL S. GIS E BURTPROF E SSIONAL E N G IN E ERREGISTERE DSTATE O F WASHI N GTONSWP - 27 - 3989S W P -3 9 8 9 PROFILES & SECTIONS-SCHEDULE A WORK PROFILE 3PROFILE 1 PROFILE 2 DETAIL This page left intentionally blank. SDMH 2475RIM=374.57IE 12" CMP NW=371.82IE 8" CONC W=370.70 (EX)IE 12" CONC S=369.57IE 12" CONC E=369.54IE 12" CONC N=369.53IE 12" DI W=370.0 (NEW)2475SSMH 2303RIM=374.91CTR CHANNEL N,E,S=362.8623032374SDCB 2374 TYPE IRIM=374.20IE 8" CONC W=372.93UNABLE TO FINDCONNECTIONWV LID=375.83'TOP NUT=373.98'2401SDCB 2401 TYPE IRIM=374.46IE 8" CONC W=372.78TO MAIN LINE2441SDCB 2441 TYPE IRIM=374.61IE 12" CMP E=372.36TO MAIN LINEAPPROX X,Y,Z OF CURB& FACE OF WALK375 375 APPROX LOCOF UTILITYPOLE2" GAS4" GASCENTURY LINKCOMM36" SPU WATER LINE SDMH 2475RIM=374.57IE 12" CMP NW=371.82IE 8" CONC W=370.70 (EX)IE 12" CONC S=369.57IE 12" CONC E=369.54IE 12" CONC N=369.53IE 12" DI W=370.0 (NEW)2475SSMH 2303RIM=374.91CTR CHANNEL N,E,S=362.8623032374SDCB 2374 TYPE IRIM=374.20IE 8" CONC W=372.93UNABLE TO FINDCONNECTIONWV LID=375.83'TOP NUT=373.98'2401SDCB 2401 TYPE IRIM=374.46IE 8" CONC W=372.78TO MAIN LINE2441SDCB 2441 TYPE IRIM=374.61IE 12" CMP E=372.36TO MAIN LINEAPPROX X,Y,Z OF CURB& FACE OF WALK375 375 APPROX LOCOF UTILITYPOLE2" GAS4" GASCENTURY LINKCOMM36" SPU WATER LINE CONSTRUCTION NOTES Planning/Building/Public Works Dept. CITY OF RENTON 999 Third Avenue, Ste 3200 Seattle, WA 98104 · 206.382.5200 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECTMICHAEL S. GIS E BURTPROF E SSIONAL E N G IN E ERREGISTERE DSTATE O F WASHI N GTONSWP - 27 - 3989S W P -3 9 8 9 PLAN & PROFILES-SCHEDULE B WORK PROFILE 4 PLAN GENERAL NOTES N This page left intentionally blank. 375374374NOTES CIVIL DETAILS SHT 1 OF 2Planning/Building/Public Works Dept. CITY OF RENTON 999 Third Avenue, Ste 3200 Seattle, WA 98104 · 206.382.5200 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECTMICHAEL S. GIS E BURTPROF E SSIONAL E N G IN E ERREGISTERE DSTATE O F WASHI N GTONSWP - 27 - 3989S W P -3 9 8 9 CONSTRUCTION NOTES ” ” DETAIL DETAIL DETAIL DETAIL This page left intentionally blank. ISOMETRIC NTS SECTION A-A NTS ELBOW RESTRICTOR DETAIL NTS 1.USE A 54" DIAMETER TYPE 2 CATCH BASIN. 2.OUTLET CAPACITY: 100-YEAR DEVELOPED PEAK FLOW. 3.METAL PARTS PREFERRED TO BE STAINLESS STEEL, ALUMINIUM STEEL, OR ALUMINIUM. ALL OTHER ALL OTHER STEEL PARTS MUST BE GALVINIZED WITH TREATMENTS 1,2, OR 5. 4.FRAME AND LADDER OR STEPS OFFSET SO: A. CLEANOUT GATE IS VISIBLE FROM TOP. B. CLIMB-DOWN SPACE IS CLEAR OF RISER AND CLEANOUT GATE. C. FRAME IS CLEAR OF CURB. 5.IF METAL OUTLET PIPE CONNECTS TO CEMENT CONCRETE PIPE: OUTLET PIPE TO HAVE SMOOTH O.D. EQUAL TO CONCRETE PIPE I.D. LESS 1/4". 6.PROVIDE AT LEAST ONE 3" X .090 GAGE SUPPORT BRACKET ANCHORED TO CONCRETE WALL. (MAXIMUM 3'-0" VERTICAL SPACING). 7.LOCATE ELBOW RESTRICTOR(S) AS NECESSARY TO PROVIDE MINIMUM CLEARANCE AS SHOWN. 8.LOCATE ADDITIONAL LADDER RUNGS IN STRUCTURES USED AS ACCESS TO TANKS AND VAULT TO ALLOW ACCESS WHEN CATCH BASIN IS FILLED WITH WATER. 9.WHEN CONNECTING TO A NEW PIPE, USE A FLEXIBLE CONNECTOR (KOR-N-SEAL BOOT WITH CORRUGATED PIPE ADAPTOR OR APPROVED EQUAL). WHEN CONNECTING TO AN EXISTIING PIPE, USE A FABRICATED SAND COLLAR OF THE SAME MATERIAL AS THE CONNECTING PIPE. 10.TEE SHALL BE CONSTRUCTED OF ALUMINUM CMP OR ALUMINIZED STEEL CMP MEETING WSDOT/APWA STANDARDS. NOTES:AADDITIONAL LADDER RUN (IN SETS) TO ALLOW ACCESS TO TANKS OR VAULTS WHEN CATCH IS FILLED WITH WATER. 2' MIN. CLEARANCE TO ANY PORTION OF FROP-T INCLUDING ELBOWS RESTRICTOR PLATE WITH 2.5 " ORIFICE DIAMETER PIPE SUPPORTS SEE NOTE 6 RIM 375.31 PLATE WELDED TO ELBOW WITH ORIFICE DIA 2 3 4 ". SEE NOTE 3 REMOVABLE WATERTIGHT COUPLING OR FLANGE ANGLE AS NECESSARY SEE NOTE 7 SHEAR GATE WITH CONTROL ROD FOR CLEANOUT/DRAIN (ROD BENT AS REQUIRED FOR VERTICAL ALIGNMENT WITH COVER) SEE STD. PLAN 237.30 HANDHOLDS, STEPS OR LADDER VERTICAL BAR GRATE FOR SECONDARY INLET INLET PIPE FRAME & SOLID COVER WITH LOCKING BOLTS PER COR STD PLAN 204.50 12" 12" 12" A 6" MAX. TOP OF RISER ELEV.=373.61 18" CPEP OUTLET PIPE 18" CMP "T" RISER IE 368.14 SEE NOTES 1 & 5 6" 2' MIN. 1.5 x D MIN.D ELBOW RESTRICTOR SEE DETAIL 2' MIN.2'2'2" MIN. 6" MIN. 2"+/- ACCESS ADJACENT TO TEE 18" RISER DIAMETER IE 366.14 ELEV.=371.11 SEE NOTE 9 (TYP.) ELBOW RESTRICTOR. SEE DETAIL AND NOTE 10 SEE NOTE 9 N PLAN VIEW 8" +/- ELEV.=371.11 24" CPEP PIPE IE 368.14 PLANT SCHEDULE NO SPECIES COMMON NAME STOCK TYPE SPACING ON CENTER (FEET)QUANTITY CIVIL DETAILS SHT 2 OF 2Planning/Building/Public Works Dept. CITY OF RENTON 999 Third Avenue, Ste 3200 Seattle, WA 98104 · 206.382.5200 HEATHER DOWNS DETENTION POND WATER QUALITY RETROFIT PROJECTMICHAEL S. GIS E BURTPROF E SSIONAL E N G IN E ERREGISTERE DSTATE O F WASHI N GTONSWP - 27 - 3989S W P -3 9 8 9 DETAIL DETAIL SECTION DETAIL This page left intentionally blank. APPENDIX E SEDIMENT TRAP SIZING CALCULATIONS APPENDIX This page left intentionally blank. City of Renton Heather Downs Water Quality Retrofit Project 5-14-20 Subject:Calculation of Sediment Pond Size Assumptions: 1)Flows will be kept in existing system so sediment pond only needs to be sized for pond surface area. 2)Use Rational Method (3.2.1) to Estimate Flows since < 10 ac. 3)Sediment Pond sizing per D.2.1.5, for Sediment Trap SA = 2080 per cfs inflow Inflow = CIA where Q = pond inflow C = runoff coefficient I = Rainfall Intensity, assume 10 yr A = Area (ac), 0.19 acres for the site Estimate of C: In this case pond will not be active until fully complete at which time the sediment trap will be removed. Therefore use C = 0.25 for Lawn I = (aR)(Tc)^(-bR), where aR and bR are coefficients from Table 3.2.1B for 2-year storm Tc = Time of Concentration, where T = L/60v and Tc is travel time in min. L is length and v is velocity (K(slope)^2) L = 115 ft slope is about 0.01 ft/ft k = 10.1 Tc = 1.9 min. I (2yr) = 1.08888 Q = 0.25 x 1.088 X 0.19 = 0.05 cfs SA = 2080 x 0.05 =166.4 sf Round to:180 sf APPENDIX This page left intentionally blank.