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Home My WebLink AboutTIR-4238 ENGINEERING REPORT Technical Information Report Seattle Sounders FC Headquarters & Training Center Renton, WA April 2023 PREPARED BY: COUGHLIN PORTER LUNDEEN 801 Second Avenue, Suite 900 Seattle, WA 98104 P 206.343.0460 CONTACT / Tim Brockway, PE, LEED AP BD+C Drainage Report Seattle Sounders FC Headquarters & Training Center Coughlin Porter Lundeen Project Number: C22010 May 2023 TABLE OF CONTENTS Drainage Report ......................................................................................................................................... 1 TABLE OF CONTENTS .............................................................................................................................. 1 I. PROJECT OVERVIEW ............................................................................................................................. 1 General Description .................................................................................................................................. 1 Existing Conditions ................................................................................................................................... 2 Proposed Drainage System ...................................................................................................................... 2 Special Requirements:.............................................................................................................................. 4 Project Specific Requirements: ................................................................................................................ 6 III. OFF-SITE ANALYSIS ............................................................................................................................ 7 Task 1 – Study Area Definition and Maps ................................................................................................ 7 Task 2 - Resource Review ....................................................................................................................... 7 Task 3 - Field Inspection .......................................................................................................................... 7 Task 4 - Drainage System Description and Problem Descriptions .......................................................... 7 Upstream Analysis 8 Downstream Analysis 8 Task 5 – Mitigation of Existing or Potential Problems .............................................................................. 8 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN .............................. 9 Existing Site Hydrology (Part A) ............................................................................................................... 9 Developed Site Hydrology (Part B) ........................................................................................................... 9 Performance Standards (Parts C) .......................................................................................................... 10 ON-site Best Management Practices (on-site BMPs) Part D ................................................................. 11 Water Quality System (Part E) ............................................................................................................... 13 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN .......................................................................... 14 Standard Requirements (based on 2022 RSWDM and SAO): .............................................................. 14 On-site Conveyance ............................................................................................................................... 15 Existing Conditions: 15 Developed Storm System Description: 15 VI. SPECIAL REPORTS AND STUDIES .................................................................................................. 16 VII. OTHER PERMITS ............................................................................................................................... 17 VIII. CSWPPP ANALYSIS AND DESIGN ................................................................................................. 18 Standard Requirements .......................................................................................................................... 18 ESC Plan Analysis and Design (Part A) ................................................................................................. 19 May 2023 SWPPS Plan Design (Part B) ................................................................................................................. 19 IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ...................... 20 X. OPERATION AND MAINTENANCE MANUAL .................................................................................... 21 Standard Maintenance ........................................................................................................................... 21 Appendix A – Figures .............................................................................................................................. 34 Figure 1 Technical Information Report Worksheet 35 Figure 2 Parcel Reports 38 Figure 3 Vicinity Map 43 Figure 4 USGS Soil Map 44 Figure 5 Existing Conditions 49 Figure 6 Drainage Basin Map 52 Figure 7 Proposed Conditions 53 Figure 8 Flow Control Application Map 55 Figure 9 FEMA FIRM Map 56 Figure 10 Downstream Analysis 57 Figure 11 Drainage Complaints 58 Figure 12 Bioscape Sizing 59 Figure 13 RSWDM Reference 8-B 60 Figure 14.A Pond B Flow Control Facility 61 Figure 14.B Pond B 24 Inch Outfall 63 Figure 14.C Longacres Existing Drainage Basins 64 Figure 15 Filterra Bioscape Treatment Facility GULD Approval 65 Figure 16 StormTech MC3500 Design Manual 92 Appendix B – Engineering Calculations .............................................................................................. 120 Figure 16 Conveyance Map 121 Figure 16.1-16.5 Conveyance Profile Plots 122 Figure 17 25-Year Pipe Analysis Table 127 Figure 18 25-Year Site Outfalls 128 Figure 19 25-Year Junction Analysis Table 129 Figure 20 25-Year Sub-Basin Summary 130 Figure 21 WWHM2012 Water Quality Sizing Report 133 Figure 22 Stormtech Chamber Sizing Calculations 159 Figure 23 Pond “B” Hydrology Analysis 168 Figure 24 Drainage Basin Map 169 Figure 25 Longacres Pond Area 170 Figure 26a Cut/Fill Heat Map 171 Figure 26b Flood Mitigation Heat Map 172 Figure 27 Filtera Bioscape Product Sheet 173 Appendix C – Supplemental Materials ................................................................................................. 174 1998 Longacres Surface Water Management Report 175 2009 Longacres Office Park Entitlements Analysis 226 Federal Emergency Management Agency Flood Insurance Study Number 53033CV001 482 1952 Response to City comments SW impacts 4-25-23 650 Appendix D – Supplemental Material Specification ........................................................................... 652 Structural Soil-Bearing Fabric Specification 653 1 I. PROJECT OVERVIEW GENERAL DESCRIPTION The following Technical Information Report (TIR) provides the technical information and design analysis required for developing the Drainage and Temporary Erosion and Sedimentation Control Plan (TESC) for the Seattle Sounders FC Headquarters & Training Center Project. The stormwater design for the project was based on the requirements set forth in the 2022 Renton Surface Water Design Manual (RSWDM) (See Figure 1 – Technical Information Report Worksheet). The Seattle Sounders FC Headquarters & Training Center Project is located within the City of Renton, situated west of Oakesdale Ave SW and south of SW 16th St, (See Figure 3 – Site Location Map). The site is in the NE ¼ of NW ¼ and NW ¼ of NE ¼ of Section 25, Township 23 North, Range 4 East, Willamette Meridian. The site will occupy lots 088670-0110, -0120, -0130, -0210, and -0220 for a total disturbed area of approximately 15 acres. Overall, the project will include 439,700 square-feet of sports fields, approximately 584,020 cubic-feet of floodplain mitigation, and the installation of storm conveyance infrastructure. Soils for the area were mapped using the King County Soil Survey maps (See Figure 4 – USDA Soil Survey Map), and a Geotechnical exploration has been performed to address slope and soil characteristics. The proposed fields will be developed upon existing open grass fields, portions of a parking lot, and a decommissioned helicopter pad. Existing swales and ponds located on the site will not be encroached upon for this project. This project proposes to construct a drainage system with a new network of underground pipes and catch basins to collect surface water runoff throughout the site and direct it to a water quality treatment facility that will be constructed adjacent to an existing detention pond (Pond B) which exists on the property. Treated water from that facility will flow into Pond B, along with higher storm events that are not subject to the requirements for water quality treatment. Pond B was designed for the Boeing Master Plan and was constructed to accommodate the full detention requirements for the overall Longacres Campus (See Appendix C for the 1998 Sverdrup Drainage Report), of which this Sounders Field Complex site is a part. From Pond B, the storm runoff flows into the North Pond (Pond A) via a flow control facility (See Figure 14) which in turn flows out to Springbrook Creek and ultimately the Duwamish River. This system is consistent with the conditions of the original Longacres Development Agreement with the City which was the basis for the existing development on the property. Additionally, a series of underground storage chambers (StormTech or Eq) is proposed to provide the flood plain fill mitigation volume, in order to comply with floodplain requirements as outlined in the City of Renton code. 2 EXISTING CONDITIONS The existing site consists of open grassy areas, a large existing office building with associated plaza and walkways. See Table 1 for site surface cover information. The site was previously home to the Longacres Racetrack outbuilding stable and support services area, which was demolished during the development of the Longacres Office Park. Minimal conveyance systems exist within the project site area and runoff now leaves the site via surface flow which makes its way ultimately to the South Pond B. There is a total elevation change of approximately 7 feet across the site, from 14.7 feet along the pond edge in the western region to 21.5 feet in the eastern region of the project limits. The site is generally otherwise considered “flat” terrain. The Pond B high water elevation of 14.7 feet was determined from the Pond’s flow control facility (See Figure 14A, The highwater line of 11.5’ is converted to 14.7’ using the NAVD 88 datum). PROPOSED DRAINAGE SYSTEM This project proposes to construct a drainage system with a new network of underground pipes and catch basins, to collect the drainage from the surface and under-drain system of the sports fields on the site, as well as the surface water runoff throughout the walkways and other areas adjacent to the fields within the project site. This system will direct runoff from the proposed fields and associated facilities to the water quality treatment system. Flows from this facility will then be directed into the existing Pond B. See Table 2 for site surface cover information. According to Figure 1.1.2.A of the 2022 Renton Surface Water Design Manual (RSWDM), this project meets the criteria for a Full Drainage Review, including water quality requirements. All water quality on site will be provided in a system, designed according to Chapter 6 of the 2022 RSWDM and complying with State Ecology GULD designation requirements. In order to provide the required enhanced basic water quality treatment for the soccer fields, the project plans to implement a Bioscape open system using Filterra media, prior to discharging to Pond B. This system has General Use Level Designation (GULD) approval for enhanced basic treatment, therefore allowing its use per the RSWDM. See Figure 15 for GULD approval. The Bioscape facility will be a scalable open-topped version of the Filterra Bioscape inlets and vaults that have been in use around Puget Sound for many years. See Image 1 below for representative images of the Bioscape system. This installation allows for a more site-integrated design at a larger scale to treat the large field system. Bioscape sizing for this project is finalized and sizing calculations are provided in Section IV of this report. Figure 12 – Bioscape Sizing, found in Appendix A, highlights the area where this system will be constructed. 3 Image 3: Filterra Bioscape System Conveyance for the Sounders site will be a combination of closed 12, 18 and 24-inch pipes. These pipes are designed to carry the field runoff to the water quality Bioscape system. Stormwater runoff from the upstream existing parking areas will be intercepted and rerouted in a 24-inch pipe through the site, to discharge into South Pond B directly as it currently does. This existing 24-inch RCP pipe has an outfall with 12” thick quarry spalls for erosion control and energy dissipation which will be reused. Another existing 12” storm will be rerouted around the proposed fields along to the northern extents to Pond B. This existing 12” storm collects runoff from the existing Longacres-Sounders facility (Building 25-20), as well as portions of the parking lot to the north. The conveyance analysis for these storm reroutes as well as the field’s drainage system can be found in Appendix B. All conveyance on site will be designed according to Chapter 4 of the 2022 RSWDM. 4 II. CONDITIONS AND REQUIREMENTS This section will address the requirements set forth by the Core and Special Requirements listed in Chapter 1 of the City of Renton Surface Water Design Manual. City of Renton Surface Water Design Manual Core Requirements: 1. Discharge at the Natural Location (1.2.1): This project proposes all runoff to be conveyed to the natural discharge location which is the existing south Pond B. 2. Off-site Analysis (1.2.2): Refer to Sections III and IV. A Level 1 downstream analysis has been performed. 3. Flow Control (1.2.3.1): Refer to Section IV. The project is in a Peak Flow Control Area. Flow control is not proposed for this project, as there is no increase in flow during the 100-year event, versus the original Pond B design, based on coverage assumptions listed with that project’s permit documentation from Sverdrup to the City. 4. Conveyance System (1.2.4): Refer to Section V. Closed pipe systems, treatment catch basin and extension connections have been provided for stormwater conveyance. 5. Erosion and Sedimentation Control (1.2.5): Refer to Section VIII and the demolition/TESC provided as part of this submittal. The project will construct a series of sediment controls to address the specific conditions at the site. 6. Maintenance and Operations (1.2.6): Refer to Section X. The proposed storm drainage system will be privately owned, operated, and maintained by Seattle Sounders FC and Unico Properties. 7. Financial Guarantees and Liability (1.2.7): The Sounders and their contractor will obtain all necessary permits and bonds prior to the beginning of construction. 8. Water Quality (1.2.8): Refer to Section IV. Water quality treatment for runoff from target pollution generating surfaces will be provided by Filterra Bioscape open filtration system. See Section IV for more information. 9. Onsite BMP (1.2.9): Refer to Section IV. Onsite BMP’s have been addressed to the maximum extent possible. See Section IV for more information. SPECIAL REQUIREMENTS: Special Requirement #1. Other Adopted Area-Specific Requirements Section 1.3.1 • Critical Drainage Areas (CDAs): Not Applicable • Master Drainage Plans (MDPs): The Development Agreement for the Boeing Longacres Masterplan governs drainage requirements for this property. While the Development Agreement is no longer active, this document is provided to provide context on the existing drainage system, its compliance with the Peak Flow runoff requirement on this campus and showing that the Sounders proposed improvements do not warrant the need for additional detention. 5 • Basin Plans (BPs): The project is located within Black River Drainage Basin. • Salmon Conservation Plans (SCPs): Not Applicable • Lake Management Plans (LMPs): Not Applicable • Shared Facility Drainage Plans (SFDPs): Not Applicable Special Requirement #2. Flood Hazard Area Delineation, Section 1.3.2: See Figure 9 for 100-yr flood zone. Filling is planned for within the 100-yr flood zone, with a total 583,800 cubic feet of fill planned between existing grade and the 20 foot 100-yr flood elevation. Compensatory volume is being provided in the footprint of the fields from elevation 14.7, which is the high water line of the detention pond, to elevation 20.0 in the form of a hybrid rock storage and chamber system like the CULTEC Recharger or StormTech system. We conservatively assume for floodplain analysis that Pond B would be at full detention when a flood occurs, thus we have set the base elevation for the flood to start in our basin as 14.7. The proposed compensatory mitigation system provides no net loss of ecological function in this property. Please also see “1952 Response to City Comments SW Impacts 4-25-23” in Appendix C for a memo from Talasaea confirming no net loss of ecological function. The site experiences backwater floods, meaning as the creek level rises the floodwater backs-up on to our property. The site is protected at several locations with salmonid screens downstream of our location, and we will provide fine mesh screens on the (2) 24 inch pipes that each set of chambers that hydraulically connect Pond B to our floodplain mitigation. The floodplain mitigation we are providing, following standard practices, provides more storage of floodwaters at lower elevations than the site currently contains. This lessens the impacts on the environment in the earlier stages of the flood while allowing for our site to maintain the same floodplain retention at the 100 year flood as it historically has. Additionally this project meets the requirements of the Code of Federal Regulations: CFR 60.3(b): Is not applicable as the area (Zone AE) has a published identified flood elevation of 20.0 ft. CFR 60.3(c)(3): The project meets this requirement as all FFE’s are 1.5 feet above the base flood elevation. CFR 60.3(c)(10): We are providing floodplain mitigation to fully offset any proposed fill inside the floodplain by this development. Special Requirement #3. Flood Protection Facilities, Section 1.3.3: Compensatory storage to offset the proposed fill within the floodplain, is proposed as described in SR#2 above. Special Requirement #4. Source Controls, Section 1.3.4: See attached Activity Worksheet and Required BMP’s. Special Requirement #5. Oil Control, Section 6.1.5. Minimal traffic is anticipated in this area. No oil control is required. Maintenance of the fields will consist of occasional small “Gator” type vehicles or pickups, on a limited basis. 6 Special Requirement #6. Aquifer Protection Area. Section 1.3.6: Not included as a special requirement in Section 1.3 of the 2009 King County Surface Water Design Manual. PROJECT SPECIFIC REQUIREMENTS: There are no applicable project specific instructions. Design and construction will abide by the requirements set forth in these documents. 7 III. OFF-SITE ANALYSIS TASK 1 – STUDY AREA DEFINITION AND MAPS The Renton drainage basin map was used to verify that the site was fully in the Black River Drainage Basin (See Figure 6 – Drainage Basin Map). TASK 2 - RESOURCE REVIEW a) Adopted Basin Plans: Black River Drainage Basin b) Floodplain/floodway (FEMA) Maps: Site is located in the floodplain (See Figure 9) c) Off-site Analysis Drainage System Table: See Figure 13, Reference 8-B d) Sensitive Areas Folio: Sensitive Areas are present on the site. See Figure 4 and the Wetland Analysis Report by Talasaea Consultants, provided separately e) Drainage Complaints and Studies: No Drainage Complaints. See Figure 11. f) Road Drainage Problems: No Current Road Drainage Problems. g) King County Soils Survey: See Figure 4 – USDA Soil Map h) Wetland Inventory Maps: See Wetland Analysis Report by Talasaea Consultants, provided separately i) Migrating Rivers Study: Not Applicable. j) DOE’s Section 303d List of Polluted Waters: The Black River Drainage Basin is not identified in Section 303d List of Polluted Waters. k) KC Designated Water Quality Problems: Not Applicable. l) City of Renton Critical Maps: See Figure 4. TASK 3 - FIELD INSPECTION Coughlin Porter Lundeen conducted site visits in preparing the project plans. Please refer to Task 4, Downstream Analysis below for more information. TASK 4 - DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS Runoff from the site will be conveyed through new and existing storm elements that discharge to the existing on-site Pond B. The proposed field project will provide a pass-through bypass pipe for the flows from the adjacent parking lot, and will itself discharge to the same location on the site, the existing Pond B. See Appendix A, Figure 10 – Downstream Analysis. 8 Upstream Analysis The site is within the Black River and specifically the Springbrook Creek drainage basin. This site is located generally at the high point of the area topography, with a limited area of train track embankment to the west that drains onto this site perimeter. Runoff from this area will be directed north or south as it currently does into offsite areas. To the east is Oakesdale Avenue, which is improved and provides no runoff to the site. To the south is Kaiser Permanente campus property which drains north through this property via a pond and ditch that connect to the existing Pond B as this project will also do. See Figure 6 – Drainage Basin Map, for reference. Downstream Analysis As delineated in red on Figure 10 – Downstream Analysis, runoff from the site will be conveyed to a new water quality vault, then into South Pond B. The site discharges to the managed stormwater system within the Longacres property which was sized and constructed in anticipation of receiving undetained and untreated runoff from this site. That system drains to Springbrook Creek in accordance with the Development Agreement and associated Master Drainage Plan for the Longacres Office Park that was previously permitted by the City and State. Springbrook Creek, in turn, drains to the Black River and, ultimately, the Duwamish River and Puget Sound. No known drainage problems have been reported with this conveyance system beyond routine maintenance such as at the City’s Oakesdale Avenue crossing culvert which frequently becomes clogged with debris based on field reconnaissance and anecdotal conversations in the past with Boeing maintenance personnel. TASK 5 – MITIGATION OF EXISTING OR POTENTIAL PROBLEMS The proposed project will not increase the originally permitted amount of impervious area, which was anticipated in the design for the current on-site ponds, A and B. The historic ground cover of this site, since before 1929 when an aerial photograph shows the presence of the original Longacres racetrack, with paddocks, maintenance yards, etc, has consisted of primarily asphalt, gravel, heavily compacted till soils, and sparse areas of compacted “lawn” as described by the RSWDM, adopted from King County SWDM. While the existing ponds and drainage systems on site were intended to be the sole water quality and detention systems needed for a fully developed site, the current Sounders facility project will be installing water quality systems in accordance with the 2022 RSWDM. A Filterra Bioscape open filtration basin is proposed at the downstream end of the new Sounders facility. This system will be sized to meet Ecology GULD requirements for treatment associated with the Enhanced Basic level as required for this project. Flows exceeding the required treatment rate will be directed around the Bioscape system via a flow splitter located above the facility. These higher flows will be directed into Pond B, which provides a Large Wetpond water quality function as described in the KCWSDM as adopted by the City of Renton into their RWSDM. 9 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN EXISTING SITE HYDROLOGY (PART A) The 13.15-acre site currently consists of a mixture of grassed and paved areas. The site slopes generally south-southeast to north-northwest with about a 3-foot elevation change throughout most of the area. Larger grade differences exist in localized areas within that plane, especially along the western edge of the project site which is adjacent to Pond B’s side-slope. The site area conditions are illustrated in Figure 7 and summarized in Table 1 below. TABLE 1 - EXISTING SITE CONDITIONS AREA BREAKDOWN DESCRIPTION TOTAL LONGACRES AREA (SF) TOTAL LONACRES AREA (ACRES) 1998 BOEING MP/EIS (%I) TOTAL SOUNDERS AREA (SF) TOTAL SOUNDERS AREA (ACRES) TOTAL PERVIOUS 2,408,877 55.30 29.2% 183,743 4.22 TOTAL IMPERVIOUS 4,473,630 102.70 70.8% 388,938 8.93 TOTAL SITE AREA 6,882,507 158.0 100% 572,680 13.15 DEVELOPED SITE HYDROLOGY (PART B) The developed site will closely resemble the original land use coverage allowed under the Boeing Longacres Master Plan and associated EIS. As described above, the historic land cover of the Longacres site is mostly impervious, with some areas of grass. The addition of the new fields and related site improvements will result in similar site hydrology as the existing Longacres (formerly Boeing) detention system was designed to accommodate. According to the definitions within the RSWDM, this project will consist of 8.09 acres of new impervious area, which includes the lined, under-drained synthetic fields, and 50% of the natural turf fields (lined with structural soil-bearing fabric with a minimum flow rate (gal/min/sq ft) of 140. See Appendix D), as well as 4.22 acres of pervious area (50% natural turf areas as well as the perimeter landscaping). The adjacent parking lot located to the east of the fields will have improvements to planters within the project area. This accounts for the remaining 0.84 acres of site to remain. These totals also include the associated hardscape being added and/or replaced on the 10 site. See Figure 7a– Proposed Conditions, for reference. The natural turf field sections will include a soil bearing fabric, however this will not impede infiltration into the native soils and the natural turf will be considered 50% pervious for the purposes of runoff modeling. TABLE 2 - DEVELOPED SITE CONDITIONS AREA BREAKDOWN DESCRIPTION AREA (SF) AREA (ACRES) PROPOSED COVERAGE TOTAL PERVIOUS 173,229 3.98 30.3% TOTAL IMPERVIOUS 399,452 9.17 69.7% TOTAL DISTURBED AREA 572,680 13.15 100.0% PERFORMANCE STANDARDS (PARTS C) According to Section 1.2.3.1 (See Figure 8 - Flow Control Application Map) of the 2022 Renton Surface Water Design Manual (RSWDM), this project is located within the Peak Flow Control area. This project lies within the tributary area to an existing detention facility developed as part of the 1998 Boeing Site Development Project. According to the Longacres Land Use Permits analysis conducted in 2009 by Perkins Cloe and Affiliates, approximately 65 percent of the 158-acre Longacres site is allocated for impervious improvement. See Appendix C for a copy of this analysis. An additional 35 percent of the site is dedicated to the detention systems and associated landscaping and open space. Removing the detention pond surface area, the remaining site has an 70.8% allocation for impervious area. The intention of the sounders Longacres development, along with the additional Longacres developments planned for the remaining site, is to remain below this impervious threshold. The sounders development remains below this threshold at 67.9%. See Appendix B Figure 23 - Pond B Hydrology Analysis for the site coverage calculations. The Longacres site is approximately 158 acres in size. This includes the sounders 13.15-acre development. See Appendix A Figure 14C for the location of the Sounders project in conjunction with the current Longacres drainage Basins. Currently the Longacres site is 30% impervious excluding the existing ponds. The Sounders development will primarily consist of natural grass and artificial turf fields. Per 2022 RSWDM table 3.2.2.B, the artificial turf fields will be treated as impervious, while 50% of the natural grass fields will be treated as 50% pervious. The proposed development will total 67.9% impervious, below the 1998 allocated threshold. The Longacres site as proposed by the 1998 report can be considered one drainage basin with two sub- basins generally draining to either Pond A or Pond B. These ponds are hydraulically linked and are both 11 considered detention ponds. This project appears to be making a small modification to the sub basin areas as roughly shown in Figure 14C by approximately 18,000 sf. This figure is not very accuracy to drainage areas in reality as it does not accurately account for existing conveyance infrastructure north of the Sounders project routing south into Pond B. This can be seen on page C3.01, C3.02, and C3.04 with the interruption and relocation of conveyance with catch basins and pipes SD D01, SD D02, SD D03, and SD D04. While the site does have separate sub-basins, the 1998 report should be viewed as a generalized study of a 158 acre site with future developments needing to look at the specifics of modifications to existing drainage. This project does not modify the drainage patterns of the site. To mitigate the impacts of storm and surface water runoff generated by new impervious surface onsite BMP’s are proposed. Per Section 1.2.9 of the 2022 Renton Surface Water Design Manual (RSWDM) for implementation of BMPs, an evaluation of the BMPs was done. Since the fields represent Pollution Generating Impervious Surfaces (PGIS) as defined by the RSWDM, a Filterra Bioscape filtration system, which conforms to State Ecology GULD requirements for Enhanced Basic criteria, is proposed. ON-SITE BEST MANAGEMENT PRACTICES (ON-SITE BMPS) PART D Onsite BMP’s have been assessed for this project to mitigate the impacts of storm and surface water runoff generated by new impervious surfaces, existing impervious surfaces, and replaced impervious surface targeted for mitigation. Due to the till soils on site, the LID performance standard does not need to be met and bioretention is being implemented for the development as a BMP. However, all other BMP’s have been assessed to the maximum extent possible per section 1.2.9 of the 2022 Renton Surface Water Design Manual (RSWDM). See assessment below. On-site BMPs Assessment SECTION REFERENCE BMP DESCRIPTION ACTION C.2.1 Full Dispersion Full Dispersion is infeasible due to the lack of vegetated area between project improvements and existing pond and wetland. C.2.2 Full Infiltration Full Infiltration is infeasible because the soil types found on site are not conducive to infiltration, per the Geotechnical Analysis. C.2.3 Limited Infiltration Limited Infiltration is potentially possible underneath the pervious natural turf field areas, which will not be lined. To be conservative, no infiltration is included in any design assumptions for stormwater design. 12 SECTION REFERENCE BMP DESCRIPTION ACTION C.2.4 Basic Dispersion Basic Dispersion is infeasible because there is not sufficient length to install a dispersion trench, and there are no locations where a “vegetated flow path segment” of at least 25-feet can be created. C.2.5 Farmland Dispersion This BMP does not apply to the City of Renton. C.2.6 Bioretention Bioretention is infeasible because the soil types found on site are not conducive to infiltration, per the Geotechnical Analysis. C.2.7 Permeable Pavement Permeable Pavement is infeasible because the soil types found on site are not conducive to infiltration, per the Geotechnical Analysis. C.2.8 Rainwater Harvesting Rainwater Harvesting is infeasible as there is no proposed building at this time to harvest rainwater from. C.2.9 Reduced Impervious Surface Credit Reduced Impervious Surface Credit requirements will not be met with this project. Due to the nature of most of the over 70% impervious surfaces this credit is infeasible. C.2.10 Native Growth Retention Credit Native Growth Retention Credit is infeasible as we are unable to provide 3.5 sf of native vegetated pervious surface for every 1 sf of new impervious surface on the site. C.2.11 Perforated Pipe Perforated Pipe has been deemed infeasible for the project because there is minor roof area which is surrounded by fields that are under-drained. C.2.12 Rain Gardens Rain Gardens infeasible because the soil types found on site are not conducive to infiltration, per the Geotechnical Analysis. C.2.13 Soil Amendment Soil Amendment is feasible and has been proposed for the site areas beyond the field fencing. C.2.14 Tree Retention Credit All trees on site outside the extents of construction are to be retained or not retained per the Arborist report. C.2.15 Vegetated Roofs Vegetated Roofs are infeasible as there is no proposed roof that is flat and can be designed for vegetation. 13 WATER QUALITY SYSTEM (PART E) Section 1.2.8.1(A) of the 2022 RSWDM outlines the specific land uses within Basic Water Quality Treatment areas which are subject to providing Enhanced Basic Water Quality treatment. The project is a commercial site making it subject to Enhanced Basic Water Quality treatment for all new and replaced pollution generating impervious surfaces (PGIS). This will be provided by the Filterra Bioscape system, which has a General Use Level Designation (GULD) from the Washington Department of Ecology for enhanced basic treatment and was deemed suitable for this application. See Figure 15 for Filterra Bioscape GULD Approval. The water quality Bioscape planter will be installed to treat runoff prior from the entire newly developed site, and then discharge into the existing Large Wetpond that is Pond B. TABLE 3. WATER QUALITY TREATMENT AREA SUMMARY REQUIRED TREATMENT AREA PROPOSED TREATMENT AREA DIFFERENCE (%) 785.8 SF 825 SF +5% According to the sizing requirements as outlined by Ecology in their GULD approval for the Filterra Bioscape system, the system on site will require roughly 785.8 sf of surface area to treat the runoff from the proposed Sounders facility improvements. Per the SEPA requirements of proximity of artificial turf fields with crumb rubber infill we are using the larger of the 2 year storm event and the water quality storm event of 91% of the Annual Storm, calibrated as required by the RSWDM Section 6.2.1 to roughly 2X (Factor k, is 1.93 for this site). The factored 91% flow rate is 2.52 cfs where the 2 year event is approximately 3.2 cfs. The Factor k of 1.93 was determined from interpolation of Table 6.2.1.A for on-line treatment facilities. According to the WWHM calculations for this project, the Filterra Bioscape facility sized to this requirement can accommodate the required flow rate of 3.2 cfs. The Bioscape provided will capture runoff from all the PGIS field areas as required. See Figure 12 – Bioscape Sizing for sizing calculations. This project shall also provide a new oil pollution control tee in SD C01 to provide enhanced protection of the existing parking lot draining into Pond B. 14 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN This section discusses the criteria that will be used to analyze and design the proposed storm conveyance system. STANDARD REQUIREMENTS (BASED ON 2022 RSWDM AND SAO): 1. Facilities must convey the 100-year flow without overtopping the crown of the roadway, flooding buildings, and if sheet flow occurs it must pass through a drainage easement. All stormwater conveyance will be designed such that the 100-year flow is conveyed without flooding any nearby buildings. 2. New pipe systems and culverts must convey the 25-year flow with at least 0.5 feet of freeboard. (1.2.4.1). The new pipe system proposed for this site will be designed to convey the 25-year flow. See Conveyance Calculations under Appendix B. These new 12” pipes will meet the conveyance requirement per Section 1.2.4.1. of the 2022 RSWDM. 3. Bridges must convey the 100-year flow and provide a minimum of two feet, varying up to six feet, of clearance based on 25% of the mean channel width. (1.2.4-2)(4.3.5-6). This project does not propose a bridge. 4. Drainage ditches must convey the 25-year flow with 0.5 feet of freeboard and the 100-year flow without overtopping. (1.2.4-2). This project does not propose open channel drainage ditches. 5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet [41(83.C)] and shall not reduce the flood storage volume [37(82.A)]. Piers shall not be constructed in the FEMA floodway. [41(83.F.1)]. The project will place 583,800 cubic feet of fill inside the floodplain. Floodplain mitigation, as is required, will be provided through the use of StormTech or Cultech arched storage chambers, typically used for detention and quite common in Western Washington. These chambers and their associated open-graded gravel backfill, are sized to provide a sub-field storage volume of 584,020 cubic feet. Of this volume 583,800 cubic feet is being provided to offset the fill of the Sounders fields project, while the remaining 220 cubic feet of floodplain mitigation is being provided to offset future construction inside the floodplain by the Longacres Masterplan project, if needed for future permitted work. Per the Federal Emergency Management Agency Flood Insurance Study Number 53033CV001B Appendix C, the 100 year flood flow at Springbook Creek/Black River and Green River confluence is 1,230 CFS at the pump station. This location is downstream of our site but will be used for analysis as conservative. The basin that floods contributing to this point covers 21.9 square miles (14,016 acres). If we conservatively assume that the 13.15 acres of this site takes a significantly larger portion of the flood water than the 0.094% of the basin that our site is, say 50x the flow, the max flow to our pipes would be 58 CFS. Our (4) 24” pipes can each maintain a 15 maximum inlet flow of 30.1 CFS per pipe which provides sufficient flow into the chambers. The 30.1 CFS is per the storage chamber manufacturer and provided in the plans and in this report. 6. Stream Crossings shall require a bridge for class 1 streams that does not disturb or banks. For type 2 and type 3 streams, open bottom culverts or other method may be used that will not harm the stream or inhibit fish passage. [60(95.B)]. The project does not propose a stream crossing. 7. Discharge at natural location is required and must produce no significant impacts to the downstream property (1.2.1-1). The project will discharge to the existing Pond B in the former Boeing Longacres site. As originally designed under the permit for those improvements that exist on-site discharge will continue into Pond B. ON-SITE CONVEYANCE Existing Conditions: Generally, stormwater runoff flows from east to west by sheet flow to a few existing catch basins on site. This runoff then flows north and northeast through the existing Longacres pond and channel system, under Oakesdale Avenue in a City culvert, to Springbrook Creek, then ultimately to Lake Washington and Puget Sound. Developed Storm System Description: The project will redevelop approximately 13.15 acres of the existing site, which currently is parking area and lawn, and replace these surfaces with a sports field complex that is described previously in this report. These new fields and their adjacent walkways will drain into a system of catch basins and under- drains, which will be routed to conveyance piping sized to accommodate the 25-year storm as required by the RSWDM. These pipes will flow west, carrying the runoff to a flow-splitter that will direct the water quality storm event flows to the proposed Bioscape water quality treatment system, and will direct larger flows directly into the existing Pond B combination Detention and Water Quality Pond, as shown in the documents. Pipe Velocity Calculation Hazen-Williams Equation: k 1.318 Conversion factor for the imperial system C 150 Roughness Coefficient (plastic) R 0.5 Hydraulic Radius (d/4) S 0.015 Slope v 13.22656 ft/s v=k×C×R 0.63 ×S 0.54 A 3.141593 ft²24" Pipe Q 41.55248 CFS Q=A×v 16 VI. SPECIAL REPORTS AND STUDIES Geotechnical Engineering Report, Longacres Field Entitlement Prepared by GeoEngineers (dated November 7, 2022) 17 VII. OTHER PERMITS This project will require a City of Renton Civil Construction permit, City of Renton Conditional Use permit, and NPDES permit. An associated Lot Line Adjustment will also be prepared and recorded to correspond with the project work extents. Building permits are required for fences over 6 feet, maintenance building, and possibly other features. See plans for comment. 18 VIII. CSWPPP ANALYSIS AND DESIGN This section lists the requirements that will be used when designing the TESC plan for this site. A copy of the Draft CSWPPP has been included at this time. STANDARD REQUIREMENTS Erosion/Sedimentation Plan shall include the following: 1. Clearing Limits a. Clearing limits are noted on plans and will be implemented prior to any offsite impacts or damage due to construction. 2. Cover Measures a. During construction, temporary cover BMPs will be implemented to prevent erosion. The project will meet wet season cover requirements. 3. Perimeter Protection a. Silt Fence will be implemented around construction limits to preserve undisturbed areas. 4. Traffic Area Stabilization a. The Contractor, per the plans, shall implement necessary BMP measures to ensure sediment does not leave the site onto streets or adjacent properties. 5. Sediment Retention a. Inlet protection will be implemented to prevent sediment from entering the existing drainage system. 6. Surface Water Collection a. Existing stormwater catch basins on-site that are proposed to remain will continue to operate during construction to collect runoff. 7. Dewatering Control a. Dewatering needs shall be monitored throughout construction. 8. Dust Control a. Dust control BMPs will be implemented throughout construction. 9. Flow Control a. Flow control is not required for the project as there will be no increase in impervious surface coverage beyond the existing approved system’s basis of design. 10. Control Pollutants a. BMPs will be implemented to prevent or treat contamination of stormwater runoff by pH modifying sources. In addition, all waste materials from the site will be removed in a manner that does not cause contamination of water. 19 11. Protect Existing and Proposed Stormwater facilities and On-Site BMPs a. Inlet protection BMPs will be implemented on the site for existing and proposed catch basins affected by construction. 12. Maintain Protective BMPs a. BMPs listed in the SWPPP shall be maintained as needed through the project. As portions of the project get completed, portions of the established BMPs shall be adjusted to other areas of the project site until their completion. 13. Manage the Project a. Proposed erosion and sediment control measures will be implemented throughout construction. ESC PLAN ANALYSIS AND DESIGN (PART A) 1. The Standard Requirements above indicate the overall ESC Plan approach and justify these methods based on circumstances specific to the Sounders field project. 2. The proposed Bioscape area (before installation) or a substitute temporary series of settling tanks such as Rain for Rent systems, will be provided to manage runoff during construction. 3. The project site is currently primarily flat with partial impervious surface coverage, giving it a low chance of erosion risk. Once construction is complete, site’s grading design will minimize on-site erosion with flat and stable sports fields and perimeter protection. 4. All techniques and products proposed for this project meet standards set in the Erosion and Sediment Control Standards in Appendix D of the City of Renton Stormwater Design Manual. SWPPS PLAN DESIGN (PART B) The CSWPPP is included. 20 IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT A Bond Quantity Worksheet is included with this report. 21 X. OPERATION AND MAINTENANCE MANUAL STANDARD MAINTENANCE All facilities are to be maintained by Seattle Sounders FC after a 2-year maintenance warranty. Sections of the 2022 Renton Surface Water Design Manual (RSWDM) under this section outline the Maintenance Requirements for stormwater facilities and on-site BMPs have been included in this section on the following pages for use by the City in the maintenance of the designed facilities. Floodplain mitigation storage (StormTech) shall be checked twice a year by Seattle Sounders FC maintenance team, as well as after all flood events. Facilities shall be cleaned per manufacturer's standards, provided below. 22 MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES AT SOUNDERS FC AT LONGACRES NO. 5 - CATCH BASINS Maintenance Component Defect Conditions When Maintenance is Needed Results Expected When Maintenance is performed General Trash & Debris (Includes Sediment) Trash or debris of more than 1/2 cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the basin by more than 10% No Trash or debris located immediately in front of catch basin opening. Trash or debris (in the basin) that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Trash or debris in any inlet or outlet pipe blocking more than 1/3 of its height. Inlet and outlet pipes free of trash or debris. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within the catch basin. Deposits of garbage exceeding 1 cubic foot in volume No condition present which would attract or support the breeding of insects or rodents. Structure Damage to Frame and/or Top Slab Corner of frame extends more than 3/4 inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than 1/4 inch (intent is to make sure all material is running into basin). Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than 3/4 inch of the frame from the top slab. Frame is sitting flush on top slab. 23 Maintenance Components Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed. Cracks in Basin Walls/ Bottom Cracks wider than 1/2 inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that structure is unsound. Basin replaced or repaired to design standards. Cracks wider than 1/2 inch and longer than 1 foot at the joint of any inlet/ outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Sediment/ Misalignment Basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Fire Hazard Presence of chemicals such as natural gas, oil and gasoline. No flammable chemicals present. Vegetation Vegetation growing across and blocking more than 10% of the basin opening. No vegetation blocking opening to basin. Vegetation growing in inlet/outlet pipe joints that is more than six inches tall and less than six inches apart. No vegetation or root growth present. Pollution Nonflammable chemicals of more than 1/2 cubic foot per three feet of basin length. No pollution present other than surface film. Catch Basin Cover Cover Not in Place Cover is missing or only partially in place. Any open catch basin requires maintenance. Catch basin cover is closed Locking Mechanism Not Working Mechanism cannot be opened by on maintenance person with proper tools. Bolts into frame have less than 1/2 inch of thread. Mechanism opens with proper tools. Cover Difficult to Remove One maintenance person cannot remove lid after applying 80 lbs. of lift; intent is keep cover from sealing off access to maintenance. Cover can be removed by one maintenance person. Ladder Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. 24 Metal Grates (If Applicable) Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and Debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. Damaged or Missing. Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. 25 NO. 9 - FENCING Maintenance Components Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Performed General Missing or Broken Parts Any defect in the fence that permits easy entry to a facility. Parts in place to provide adequate security. Erosion Erosion more than 4 inches high and 12-18 inches wide permitting an opening under a fence. No opening under the fence that exceeds 4 inches in height. Wire Fences Damaged Parts Post out of plumb more than 6 inches. Post plumb to within 1- 1/2 inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence (including post, top rails) more than 1 foot out of design alignment. Fence is aligned and meets design standards. Missing or loose tension wire. Tension wire in place and holding fabric. Extension arm missing, broken, or bent out of shape more than 1 1/2 inches. Extension arm in place with no bends larger than 3/4 inch. Deteriorated Paint or Protective Coating Part or parts that have a rusting or scaling condition that has affected structural adequacy. Structurally adequate posts or parts with a uniform protective coating. 26 NO. 6 - CONVEYANCE SYSTEMS (PIPES & DITCHES) Maintenance Component Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Pipes Sediment & Debris Accumulated sediment that exceeds 20% of the diameter of the pipe. Pipe cleaned of all sediment and debris. Vegetation Vegetation that reduces free movement of water through pipes. All vegetation removed so water flows freely through pipes. Damaged Protective coating is damaged; rust is causing more than 50% deterioration to any part of pipe. Pipe repaired or replaced. Any dent that decreases the cross section area of pipe by more than 20%. Pipe repaired or replaced. Open Ditches Trash & Debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment Accumulated sediment that exceeds 20 % of the design depth. Ditch cleaned/ flushed of all sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion Damage to Slopes See “Rain gardens” Standard No. 1 See “Rain gardens” Standard No. 1 Rock Lining Out of Place or Missing (If Applicable). Maintenance person can see native soil beneath the rock lining. Replace rocks to design standards. Catch Basins See “Catch Basins: Standard No. 4 See “Catch Basins” Standard No. 4 Debris Barriers (e.g., Trash Rack) See “Debris Barriers” Standard No.5 See “Debris Barriers” Standard No. 5 27 NO. 11 - GROUNDS (LANDSCAPING) Maintenance Component Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Performed General Weeds (Nonpoisonous) Weeds growing in more than 20% of the landscaped area (trees and shrubs only). Weeds present in less than 5% of the landscaped area. Safety Hazard Any presence of poison ivy or other poisonous vegetation. No poisonous vegetation present in landscaped area. Trash or Litter Paper, cans, bottles, totaling more than 1 cubic foot within a landscaped area (trees and shrubs only) of 1,000 square feet. Area clear of litter. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. Tree or shrub in place free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; remove any dead or diseased trees. 28 NO. 12 - ACCESS ROADS/ EASEMENTS Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 square feet i.e., trash and debris would fill up one standards size garbage can. Roadway free of debris which could damage tires. Blocked Roadway Debris which could damage vehicle tires (glass or metal). Roadway free of debris which could damage tires. Any obstruction which reduces clearance above road surface to less than 14 feet. Roadway overhead clear to 14 feet high. Any obstruction restricting the access to a 10 to 12 foot width for a distance of more than 12 feet or any point restricting access to less than a 10 foot width. Obstruction removed to allow at least a 12 foot access. Road Surface Settlement, Potholes, Mush Spots, Ruts When any surface defect exceeds 6 inches in depth and 6 square feet in area. In general, any surface defect which hinders or prevents maintenance access. Road surface uniformly smooth with no evidence of settlement, potholes, mush spots, or ruts. Vegetation in Road Surface Weeds growing in the road surface that are more than 6 inches tall and less than 6 inches tall and less than 6 inches apart within a 400-square foot area. Road surface free of weeds taller than 2 inches. 29 NO. 12- WATER QUALITY FACILITIES A.) Filterra Bioscape Maintenance Component Defect or Problem Condition When Maintenance is Needed Recommended Maintenance to Correct Problem Facility – General Requirements Life cycle Twice per year. Facility is re-inspected and any needed maintenance performed Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries, or paint Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet Excessive sediment or trash accumulation Accumulated sediments or trash impair free flow of water into system inlet should be free of obstructions allowing free distributed flow of water into system Mulch Cover Trash and floatable debris accumulation Excessive trash and/or debris accumulation Minimal trash or other debris on mulch cover. Mulch cover raked level. Proprietary Filter Media/ Vegetation Substrate “Ponding” of water on mulch cover after mulch cover has been maintained Excessive fine sediment passes the mulch cover and clogs the filter media/vegetative substrate Stormwater should drain freely and evenly through mulch cover. Replace substrate and vegetation when needed Plants not growing or in poor condition Soil/mulch too wet, evidence of spill, incorrect plant selection, pest infestation, and/or vandalism to plants Plants should be healthy and pest free Damaged Pipes Any part of the pipes that are crushed, damaged due to corrosion and/ or settlement. Pipe repaired and/ or replaced. Appendix A – Figures Figure 1 Technical Information Report Worksheet Figure 2 Parcel Reports Figure 3 Vicinity Map Figure 4 USGS Soil Map Figure 5 Existing Conditions Figure 6 Drainage Basin Map Figure 7 Proposed Conditions Figure 8 Flow Control Application Map Figure 9 FEMA FIRM Map Figure 10 Downstream Analysis Figure 11 Drainage Complaints Figure 12 Bioscape Sizing Figure 13 RSWDM Reference 8-B Figure 14.A Pond B Flow Control Facility Figure 14.B Pond B 24 Inch Outfall Figure 14.C Longacres Existing Drainage Basins Figure 15 Filterra Bioscape Treatment Facility GULD Approvavl Figure 16 StormTech MC3500 Design Manual King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner: Seattle Sounders FC Project Name: Seattle Sounders FC Headquarters & Training Center Address: 159 S. Jackson Street Suite 200, Seattle, WA 98104 Location Phone: Township: 23N Range: 4E Section: 24 Project Engineer: Tim Brockway, P.E., LEED AP BD+C Company: Coughlin Porter Lundeen Address/Phone: 801 Second Avenue, Ste 900 Seattle, WA 98104 (206) 343-0460 Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Subdivison Short Subdivision Grading Commercial Other: DFW HPA Shoreline Management COE 404 Rockery DOE Dam Safety Structural Vaults FEMA Floodplain Other N/A COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: Drainage Basin: Black River Drainage Basin Part 6 SITE CHARACTERISTICS River Stream Critical Stream Reach Depressions/Swales Lake Floodplain Limited Wetlands Seeps/Springs High Groundwater Table Groundwater Recharge Steep Slopes Other Part 7 SOILS Soil Type Slopes Erosion Potential Erosive Velcoties Ur <15% Low Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT Ch.4 – Downstream Analysis None Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Sedimentation Facilities Stabilized Construction Entrance Perimeter Runoff Control Clearing and Graing Restrictions Cover Practices Construction Sequence Other Stabilize Exposed Surface Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris Ensure Operation of Permanent Facilities Flag Limits of SAO and open space preservation areas Other Part 10 SURFACE WATER SYSTEM Grass Lined Channel Pipe System Open Channel Dry Pond Wet Pond Tank Vault Energy Dissapator Wetland Stream Infiltration Depression Flow Dispersal Waiver Regional Detention Method of Analysis Compensation/Mitigati on of Eliminated Site Storage Brief Description of System Operation The project proposes to construct a drainage system with a new network of underground pipes, catch basins, curbs and gutter, to collect surface water runoff throughout the site and direct it to a combined detention wetpond located on Boeing's Tract B for both water quality treatment and detention. Facility Related Site Limitations Reference Facility Limitation N/A Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS Cast in Place Vault Retaining Wall Rockery > 4’ High Structural on Steep Slope Other N/A Drainage Easement Access Easement Native Growth Protection Easement Tract Other Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate. Signed/Date 8/1/22, 1:18 PM King County Districts and Development Conditions for parcel number 0886700110 https://www5.kingcounty.gov/kcgisreports/dd_report_print.aspx?PIN=0886700110&aerial=false 1/1 King County Districts and Development Conditions for parcel 0886700110 Parcel number 0886700110 Address Jurisdiction Renton Zipcode 98057 Kroll Map page 335 Thomas Guide page 655 Drainage Basin Black River Watershed Duwamish - Green River WRIA Duwamish-Green (9) PLSS SE - 24 - 23 - 4 Latitude 47.4621 Longitude -122.23588 King County Electoral districts Voting district RNT 11-2582 King County Council district District 5, Dave Upthegrove (206) 477-1005 Congressional district 9 Legislative district 11 School district Renton #403 Seattle school board district does not apply (not in Seattle) District Court electoral district Southeast Regional fire authority district Renton Regional Fire Authority Fire district does not apply Water district does not apply Sewer district does not apply Water & Sewer district does not apply Parks & Recreation district does not apply Hospital district Public Hospital District No. 1 Rural library district Rural King County Library System Tribal Lands?No King County planning and critical areas designations* King County zoning NA, check with jurisdiction Development conditions None Comprehensive Plan Land Use Designation does not apply Urban Growth Area Urban Community Service Area does not apply Community Planning Area Green River Valley Coal mine hazards?Check with jurisdiction Erosion hazards?Check with jurisdiction Landslide hazards?Check with jurisdiction Seismic hazards?Check with jurisdiction Urban Unincorporated Status does not apply Rural town?No Water service planning area City of Renton Transportation Concurrency Management does not apply Forest Production district?No Agricultural Production district?No Snoqualmie Valley watershed improvement district? No Critical aquifer recharge area?None mapped Wetlands at this parcel?Check with jurisdiction Within the Tacoma Smelter Plume?20 ppm to 40 ppm Estimated Arsenic Concentration in Soil Shoreline management designation (% of parcel) None mapped This report was generated on 8/1/2022 1:17:00 PM Contact us at giscenter@kingcounty.gov. © 2022 King County Map Sat 8/1/22, 1:20 PM King County Districts and Development Conditions for parcel number 0886700120 https://www5.kingcounty.gov/kcgisreports/dd_report_print.aspx?PIN=0886700120&aerial=true 1/1 King County Districts and Development Conditions for parcel 0886700120 Parcel number 0886700120 Address Jurisdiction Renton Zipcode 98057 Kroll Map page 335 Thomas Guide page 655 Drainage Basin Black River Watershed Duwamish - Green River WRIA Duwamish-Green (9) PLSS SE - 24 - 23 - 4 Latitude 47.46072 Longitude -122.23673 King County Electoral districts Voting district RNT 11-2582 King County Council district District 5, Dave Upthegrove (206) 477-1005 Congressional district 9 Legislative district 11 School district Renton #403 Seattle school board district does not apply (not in Seattle) District Court electoral district Southeast Regional fire authority district Renton Regional Fire Authority Fire district does not apply Water district does not apply Sewer district does not apply Water & Sewer district does not apply Parks & Recreation district does not apply Hospital district Public Hospital District No. 1 Rural library district Rural King County Library System Tribal Lands?No King County planning and critical areas designations* King County zoning NA, check with jurisdiction Development conditions None Comprehensive Plan Land Use Designation does not apply Urban Growth Area Urban Community Service Area does not apply Community Planning Area Green River Valley Coal mine hazards?Check with jurisdiction Erosion hazards?Check with jurisdiction Landslide hazards?Check with jurisdiction Seismic hazards?Check with jurisdiction Urban Unincorporated Status does not apply Rural town?No Water service planning area City of Renton Transportation Concurrency Management does not apply Forest Production district?No Agricultural Production district?No Snoqualmie Valley watershed improvement district? No Critical aquifer recharge area?None mapped Wetlands at this parcel?Check with jurisdiction Within the Tacoma Smelter Plume?20 ppm to 40 ppm Estimated Arsenic Concentration in Soil Shoreline management designation (% of parcel) None mapped This report was generated on 8/1/2022 1:20:00 PM Contact us at giscenter@kingcounty.gov. © 2022 King County Map Sat 8/1/22, 1:20 PM King County Districts and Development Conditions for parcel number 0886700130 https://www5.kingcounty.gov/kcgisreports/dd_report_print.aspx?PIN=0886700130&aerial=true 1/1 King County Districts and Development Conditions for parcel 0886700130 Parcel number 0886700130 Address Jurisdiction Renton Zipcode 98057 Kroll Map page 335 Thomas Guide page 655 Drainage Basin Black River Watershed Duwamish - Green River WRIA Duwamish-Green (9) PLSS SE - 24 - 23 - 4 Latitude 47.46078 Longitude -122.23548 King County Electoral districts Voting district RNT 11-2582 King County Council district District 5, Dave Upthegrove (206) 477-1005 Congressional district 9 Legislative district 11 School district Renton #403 Seattle school board district does not apply (not in Seattle) District Court electoral district Southeast Regional fire authority district Renton Regional Fire Authority Fire district does not apply Water district does not apply Sewer district does not apply Water & Sewer district does not apply Parks & Recreation district does not apply Hospital district Public Hospital District No. 1 Rural library district Rural King County Library System Tribal Lands?No King County planning and critical areas designations* King County zoning NA, check with jurisdiction Development conditions None Comprehensive Plan Land Use Designation does not apply Urban Growth Area Urban Community Service Area does not apply Community Planning Area Green River Valley Coal mine hazards?Check with jurisdiction Erosion hazards?Check with jurisdiction Landslide hazards?Check with jurisdiction Seismic hazards?Check with jurisdiction Urban Unincorporated Status does not apply Rural town?No Water service planning area City of Renton Transportation Concurrency Management does not apply Forest Production district?No Agricultural Production district?No Snoqualmie Valley watershed improvement district? No Critical aquifer recharge area?None mapped Wetlands at this parcel?Check with jurisdiction Within the Tacoma Smelter Plume?20 ppm to 40 ppm Estimated Arsenic Concentration in Soil Shoreline management designation (% of parcel) None mapped This report was generated on 8/1/2022 1:20:35 PM Contact us at giscenter@kingcounty.gov. © 2022 King County Map Sat 8/1/22, 1:21 PM King County Districts and Development Conditions for parcel number 0886700210 https://www5.kingcounty.gov/kcgisreports/dd_report_print.aspx?PIN=0886700210&aerial=true 1/1 King County Districts and Development Conditions for parcel 0886700210 Parcel number 0886700210 Address Jurisdiction Renton Zipcode 98057 Kroll Map page 335 Thomas Guide page 656 and 655 Drainage Basin Black River Watershed Duwamish - Green River WRIA Duwamish-Green (9) PLSS SE - 24 - 23 - 4 Latitude 47.4608 Longitude -122.234 King County Electoral districts Voting district RNT 11-2582 King County Council district District 5, Dave Upthegrove (206) 477-1005 Congressional district 9 Legislative district 11 School district Renton #403 Seattle school board district does not apply (not in Seattle) District Court electoral district Southeast Regional fire authority district Renton Regional Fire Authority Fire district does not apply Water district does not apply Sewer district does not apply Water & Sewer district does not apply Parks & Recreation district does not apply Hospital district Public Hospital District No. 1 Rural library district Rural King County Library System Tribal Lands?No King County planning and critical areas designations* King County zoning NA, check with jurisdiction Development conditions None Comprehensive Plan Land Use Designation does not apply Urban Growth Area Urban Community Service Area does not apply Community Planning Area Green River Valley Coal mine hazards?Check with jurisdiction Erosion hazards?Check with jurisdiction Landslide hazards?Check with jurisdiction Seismic hazards?Check with jurisdiction Urban Unincorporated Status does not apply Rural town?No Water service planning area City of Renton Transportation Concurrency Management does not apply Forest Production district?No Agricultural Production district?No Snoqualmie Valley watershed improvement district? No Critical aquifer recharge area?None mapped Wetlands at this parcel?Check with jurisdiction Within the Tacoma Smelter Plume?20 ppm to 40 ppm Estimated Arsenic Concentration in Soil Shoreline management designation (% of parcel) None mapped This report was generated on 8/1/2022 1:21:13 PM Contact us at giscenter@kingcounty.gov. © 2022 King County Map Sat 8/1/22, 1:21 PM King County Districts and Development Conditions for parcel number 0886700220 https://www5.kingcounty.gov/kcgisreports/dd_report_print.aspx?PIN=0886700220&aerial=true 1/1 King County Districts and Development Conditions for parcel 0886700220 Parcel number 0886700220 Address 1901 OAKESDALE AVE SW Jurisdiction Renton Zipcode 98057 Kroll Map page 335 Thomas Guide page 656 and 655 Drainage Basin Black River Watershed Duwamish - Green River WRIA Duwamish-Green (9) PLSS SE - 24 - 23 - 4 Latitude 47.46217 Longitude -122.23408 King County Electoral districts Voting district RNT 11-2582 King County Council district District 5, Dave Upthegrove (206) 477-1005 Congressional district 9 Legislative district 11 School district Renton #403 Seattle school board district does not apply (not in Seattle) District Court electoral district Southeast Regional fire authority district Renton Regional Fire Authority Fire district does not apply Water district does not apply Sewer district does not apply Water & Sewer district does not apply Parks & Recreation district does not apply Hospital district Public Hospital District No. 1 Rural library district Rural King County Library System Tribal Lands?No King County planning and critical areas designations* King County zoning NA, check with jurisdiction Development conditions None Comprehensive Plan Land Use Designation does not apply Urban Growth Area Urban Community Service Area does not apply Community Planning Area Green River Valley Coal mine hazards?Check with jurisdiction Erosion hazards?Check with jurisdiction Landslide hazards?Check with jurisdiction Seismic hazards?Check with jurisdiction Urban Unincorporated Status does not apply Rural town?No Water service planning area City of Renton Transportation Concurrency Management does not apply Forest Production district?No Agricultural Production district?No Snoqualmie Valley watershed improvement district? No Critical aquifer recharge area?None mapped Wetlands at this parcel?Check with jurisdiction Within the Tacoma Smelter Plume?20 ppm to 40 ppm Estimated Arsenic Concentration in Soil Shoreline management designation (% of parcel) None mapped This report was generated on 8/1/2022 1:21:46 PM Contact us at giscenter@kingcounty.gov. © 2022 King County Map Sat 2014Project Site FIGURE 3 - Vicinity Map BeD BeD BeC AkF AmC KpD AmB AmB AgC AgC AgC KpB AgC AkF BeD AgC KpD AgCKpBKpBAgD EvC Bh BeC AgB KpB AgD UrEwC EvB AmC Or AgC BeC BeD BeD BeC AgC KpD BeC KpCKpB Sk AmC BeC UrBeCUr AgD KpB Ur AgC EvC KpC AgC OvD SkAgB AgB AgD EvC W OvD OvD No AgC AgD EvC RdC Sk KpB No AgCRdEAgCEvC BeC InC Bh BeDRdC AkF AgD BeD BhSm AgC RdE AgC AgDEvC Sh Sh PITS PyAgC AgD AgC EvC PITS EvB BeC OvC PITS EvB AgC InA AgD AgD Ur Bh AgC RdCEvCEvD AmB AmC AgD BeD EvC AkF AgD AgC Sm AgD AmC EvB AgD Sm AgC EwC PITSPu Bh Bh AgC KpD Tu AgC EvC EvC Ur RdC KpB RdCRdE W AgD AgD No AgB AgC No An AkF EvB InD AgD EvDInC SkBeC PITS Ur WBeC W BeD An EvC BeC Pc EvC Rh AmC BeCBeD BeD Ur BeC Ur W W Rh EvC AkF PITS AgD AmCPITS Wo Py Tu BeD EvB Py AmC Py An InC Ng AgC AgC W EvB AgD AgCWo Ur W Ur RdC Ur Ur EvC Rh Pc PyPy AgD AmC AgD MaRh Pc BeD Py Ng AmC Ng BeC AgC Rh AgD Py Ma PyRh RhRhPu Pu Ur Pu PITS BeD Rh EvC Py Wo Wo AgC Ma AgD AgB So Ng AgD Tu Py AgC AgC AgC AgC Ng Ur AgD Sk AmB AgB AgD PuUr Py Sk Ur No AgB MaBeC W AkFBeDPu Py NoNo AmC AgC EvC Ma Sk EvC AgB Py InC SkAmC AmC AgC AgB SkAgBPITS AgC No Pu AmB EvC PITS AmB AgB AkF AkF Ng AgD AgD AgB EvBAmB AmCAmCWo Ng PITS Nk AgD SkNk SkAgB Ur AgD Wo AmC No AgD NoUr AgB Ur Br Py Os So EvB Ur Nk Wo AmB W Pc OsRe UrAmB Sk W AmC Tu No Pu AgD AmBAkFAgCNo UrPk AgB AgC Ur AmB NoAmC NoAmC AmB PITS UrSkAgCAgB AgC Re AgB W InC No AgC Wo EvC NoAmC Wo AgB AgB Ur Ng SkAmB ReOs AgCNo AgD No Ur No InC AgD EvC Tu AmB EvB AgD Pu InC EvCAmC NoEvC Ur EvB AkFBr Os AgD AmC AgB AgD AmBOs Os NoAmC Pk AkF No AmC EvC NoNo AgDBr AgBAgC AgBAmC Re Re KpBAmBNoPyPySkNgAgBEvC EvC Sk NoEvBNo Pu BrPuOsOsWo AmC PantherLake LakeYoungs LakeWashington B l a ck Riv er Gre enR iverCeda rRiverDuwamish Wat erwa yUV167 UV900 UV515 UV169 UV900 UV167BN IncBN IncBBNNIInnccSSEE RReennttoonnIIss ss aa qquuaahhRRdd S 2nd StS 2nd St RReennttoonnMMaapplleeVVaalllleeyyRRdd MMaapplleeVVaalllleeyyHHwwyy 110088tthhAAvveeSSEEMMaaiinnAAvveeSSMM aarrttiinn LL KKiinnggJJrrWWaayySS SSWW SSuunnsseettBBllvvdd RRaaii nnii eerr AAvveeNNNE 3rd StNE 3rd St II--440055FFWWYYSW 43rd StSW 43rd St SSEE CCaarrrrRR dd NE 4th StNE 4th St SS GG rr aa dd yy WW aa yy SSEERReennttoonnMMaapplleeVVaalllleeyy RRddLLooggaannAAvveeNN SR 515SR 515PPaarrkkAAvveeNNBBeennssoonnDDrrSSSSuunnsseettBBllvvddNN OOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNNEE DDuuvvaallllAAvveeNNEESR 167SR 167114400tthh WWaayySSEEWWaatteerrss AA vvee SS NNEE2277tthh SStt HHoo uu ss eerr WWaayyNN115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St PPuuggeettDDrrSSEERR eennttoonnAAvvee SS GGaarrddeennAAvveeNNSSWW 2277tthh SStt BBeennssoonnRRddSSWWiilllliiaammssAAvveeSSMMoonnrrooeeAAvveeNNEEII nntt eerr uurr bbaannAAvv eeSS HHooqquuiiaammAAvveeNNEE8844tthhAAvveeSSSSEEPPeettrroovviittsskkyyRRdd SSoouutthhcceenn tt ee rr BB llvvdd EEVVaalllleeyyHHwwyySShhaattttuucckkAAvveeSSRRaaiinniieerrAAvveeSS TTaallbboottRRddSSRR ee nnttoo nn AA vv ee SS116644tthhAAvveeSSEESE 208th StSE 208th St SSWWLLaannggssttoonnRRdd SE 72nd StSE 72nd St SE 128th StSE 128th St 112244tthhAAvveeSSEES 128th StS 128th St NNeewwccaassttllee WWaayy SS 221122tthh SStt SS 118800tthh SStt CCooaallCCrr ee eekkPPkkwwyySSEESW 41st StSW 41st St N 30th StN 30th St T a y l o r P l NW T a y l o r P l NW114400tthhAAvveeSSEE112288tthhAAvveeSSEE111166tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt NE 12th StNE 12th St BBeeaaccoonn AA vv ee SS FFoorreessttDDrrSSEE UUnniioonnAAvveeSSEESE 164th StSE 164th St NNiilleeAAvveeNNEE114488tthhAAvveeSSEESSEEMMaayyVVaalllleeyy RRdd SS EE 22 00 44 tthh WW aayySW 34th StSW 34th St SSEE JJoonneess RR dd SE 144th StSE 144th StEEMMeerrcceerrWWaayy 114488tthhAAvveeSSEEWWMMeerrcceerrWWaayy115544tthhPPllSSEEEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405 ,§-405 Reference 15-C Renton City Limits Potential Annexation Area Groundwater Protection Area Boundary Aquifer Protection Area Zone 1 Aquifer Protection Area Zone 1 Modified Soil Type AgB AgC AgD AkF AmB AmC An BeC BeD Bh Br EvB EvC EvD EwC InA InC InD KpB KpC KpD Ma Ng Nk No Or Os OvC OvD PITS Pc Pk Pu Py RdC RdE Re Rh Sh Sk Sm So Tu Ur W Wo Date: 01/09/2014 0 1 2MilesµSoil Survey Project Location Figure 4A - Soil Survey Map Project Location Figure 4B - Wetlands and Water Classifications Project Location Figure 4C - Aquifer Protection Project Location Figure 4D - Erosion Hazard Project Location Figure 4E - Flood Hazard XΔSSxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxS SDxWxWxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxZONEAESDxSDxSDxSDxSDxSDxSDx S D x SDxSDxS SDxSDxSDxSDxSDxWx SDxSDxSDxSDxSDx SDxSDxSDxSDxSDxWxWxWxWxSCALE 1"=100'FIGURE 5AExisting ConditionsPervious: 464,788 SF (10.67 ac) (Includes 50% of area.) NPGIS: 8,886 SF (0.20 ac) (Includes 50% of area.) PGIS: 99,006 SF (2.27 ac)Ex. Gravel: 5,018 SF (0.12 AC) Calculated as 50% Pervious & 50% ImperviousLegend SCALE 1"=390'FIGURE 5BHistorical ConditionsLegendPerviousNPGISPGIS Roof 17,904 sf Roof 13,356 sf Roof 8,744 sfRoof 8,744 sf Roof 3,993 sf Roof 3,259 sf Roof 12,865 sfRoof 3,617 sf Roof 10,715 sf Roof 7,161 sf Roof 4,718 sfRoof 4,335 sfRoof 4,929 sfRoof 5,284 sfRoof 4,373 sfRoof 5,192 sf Roof 4,287 sfRoof 4,164 sfRoof 4,818 sfRoof 4,001 sfRoof 3,769 sfRoof 5,515 sf Roof 3,296 sfRoof 4,444 sfRoof 5,151 sfRoof 4,986 sfRoof 5,482 sfRoof 4,859 sfRoof 11,722 sfRoof 5,721 sfRoof 4,672 sfRoof 4,751.5 sfRoof 4,342 sf Roof 7,050 sfRoof 6,116 sfRoof 5,658 sfRoof 4,601.5 sfRoof 4,697.5 sf Roof 4,782 sfRoof 4,457 sfRoof 4,634 sfRoof 4,585 sfRoof 4,711.5 sfRoof 4,999.5 sfRoof 2,559.5 sf Roof 5,471 sfRoof 6,642.5 sf Roof 12,707.5 sf Roof 11,512 sf Roof 7,804 sf Roof 8,223 sf Roof 11,751.5 sf Roof 11,202.5 sf Roof 11,114 sf Roof 12,155 sf Roof 8,910.5 sf Roof 10,114.5 sf Roof 9,970.25 sf Roof 9,464 sf Roof 13,453.75 sf Roof 12,753.25 sf Roof 10,886.5 sf Roof 14,450.5 sfRoof 5,619.63 sf Roof 4,130.75 sf Roof 33,572 sf Roof 7,805.5 sfRoof 15,145.75 sf Roof 16,412.75 sf Roof 10,454.5 sf Roof 12,734.5 sf Roof 11,507.75 sf Roof 3,186.38 sf Total Site Area 5,015,066 sf Roof 4,937.5 sf Roof 4,523.5 sf Impervious 104,940 sf Impervious 36,329 sf Impervious 12,918 sf Impervious 12,161 sfImpervious 6,559 sf Impervious 10,591 sfImpervious 3,516 sf Impervious 9,385 sf Impervious 3,509 sfImpervious 12,084 sf Gravel 249,790.8 sf Gravel 312,138.3 sf Gravel 91,719.88 sf Gravel 52,478.38 sf Impervious 21,406.5 sf impervious 60,715.5 sf Gravel 150,670.9 sf Gravel 37,920 sf Gravel 13,793.75 sf Gravel 28,297.25 sf Gravel 31,606 sf Gravel 35,673.5 sf Gravel 30,267.5 sf Gravel 26,962.5 sf Gravel 34,916.5 sf Gravel 29,769 sf Gravel 55,286.5 sf Gravel 10,905.5 sf Gravel 18,169.5 sf Gravel 12,054.5 sf Gravel 5,708 sf Gravel 45,825 sf Gravel 14,747.5 sf Gravel 14,251.5 sf Legend Label Quantity Unit Total Pervious 2,256,947.40 sf Gravel 3,200.75 sf Gravel 2,578 sf Gravel 2,067.5 sf Gravel 2,287 sf Gravel 2,446.5 sf Gravel 2,313 sf Gravel 2,967.25 sf Gravel 2,634.25 sf Impervious 534,509.3 sf Impervious 84,121.63 sf FIGURE 5B Historical Conditions - Surface Area Correlation BN I nc4th Rainier Lind3rd Cedar River 140thPetrovitskyI-405TalbotParkGrady I- 5 SR 167108th148thInterurban68thBe nso n84thLogan 95th 144thDuvall78th 16th WellsAndoverOakesdale27th SR 515Coal Cre ek128th 72nd43rd MercerWest Valley8th May Valley C a rr116th 79th 76t hPuget6th 164thRenton Issaquah 134th KirklandFairwood Renton Maple ValleyMonroe Southcenter132nd 8 0th 204th 41st East Valley34th 8 9th Langston 5th 200thUnionWilliamsBeacon 154thHoquiamMaple Valley57th9th 30th Forest JonesSeward ParkNewcastle Aberdeen184thBangor 88th 169th SR 900194th CornellHarringtonHardieValleyPelly56th 58th183rd121st 161st62nd168th149th64th Parkside96th63rdGarden186th Strander 87th19th Mill Sunset 176th59thPedestrian156th12th 21st 70th 175thLincoln125th135th Leo 61st31st 155th92nd Dixon 118th24th81st Renton133rd 2nd 166th15th Lakemont160th 10th 14th Avon Island CrestTukwilaMaule Newcastle Golf Club 171stEdmonds39th 141st Martin L King Jr Taft 29th Blaine192nd 180th FieldTobin Lakeridge Sidney 114th 208th 177th196th174th106th53rd38th93rd32nd 83rd Lake Yo ungs TrailShattuck 142nd 82nd 136thCrestwoodAccess112th Licorice 143rd23rd Soos Creek WoodsideBronsonHolly 131stNorfolk 138th 104th52ndIndex 159th55thPerimeter 105th199th 178th 65th 66th 71st Airport BurnettRoyal Hills123rd1 26 thOlympiaMonster 75th Hou s erWoodley 190th I sl and7th 28th 167th35th Rosario8 5th 1st 33rd 91st IndustryFir Macad am60thSu nnycres tAnacortesLynnwoodMinkler Rustic103rd98thLake 17 3rd A cc e ss R d w y LyonsFrager181st22nd 130th 145thRiv ersi de158th111thSperryTaylor 102nd 40th Pasco15 1 st 198th 179thDavisBeacon Coal Mine 201st Baker Ryan Nile110t hG reen Ri ver 69th124thOthello MapleAuburn 188th 170th137thWabash Avalon 129thAWest Lake Desire Pierce54th Klickitat 193rd Lake Youngs Service 73rd Railroad 13 th195thMorris139th109th36th122ndPrivateBoeing 11 7t h1 20th 157th47thTodd 25th Myrtle Ferndale MainFletcher Juniper Luther 113th20th 209th163rd77thLake Washi ngtonPowellCed ar 1 46th 150th 182nd172ndThomasHillside Pilgrim High17thWaters 99thHazelwood42nd OlympicEast Lake DesireShelt onKenyon 206th Triland 10 0th VashonStevens97th187th OrcasOakOld Petrovitsky 119th 147thRolling HillsLake YoungsRussell6th pl 11th Hazel W indsor45th 165thWallace 202nd 48th 152nd37th JeffersonPine26th 127th Victoria 115th67th 191st Camas 185th 94thLaurel GlenwoodJericho107thRose Eden 90th Costco WillowBrighton NachesCapri203rd 18th Upland Chri stensenSunwoodCedar RidgeHouser Way BypassM onterey Kent BoeingRipleyRenton TC86th Eagle Ridge44th Ilwaco212thKennewick50thSeneca County Road 66 Meadow GrantLongacres153rd Lima Arrowsmith Dayt onQuinceyMidland G e mMountain View46th 74th 101st Segale Park B189th WhitmanPrentice 162ndFoun tain Center Point207th Warsaw Treck ElmaQueenPark Access Shore Renton Dist CtChelanLewis 855th Oaksdale197th Gazelle Augusta 136 Talbot CrestKitsapUnn a me d Boein g Re nt onNel sonGe ne C o ulo n Park 49th Ridgecrest Victor Park ViewRedmondMosesTacomaHolyokeRoxbury S mith ers Nels BerglundEvergreen Lake View Raymond Riverview Park BremertonGrahamSouthcenter Mall Whitworth Eastwood Cooper Berkshire AptWestwood Duncan Kentridge HS Corporate 95th 140th 120th 150th1st 119th3rd 139th 77th 71st 184th 18th 144th Lincoln1 81s t118th145t hVashonAccess143rd139t h65th 182nd 114th61st116th 148th64th11th Kir kl and10th 147thHoquiam70th105th121st I-584th61stAccess142ndPrivate 172nd137th173rd140th 134th112th 166t h1 2 4th 8th Morris86thPri vat eCamas124th 74th 105th74th 142nd 192nd 167th 146th126th 155th 162nd AccessWilliams 184th3rd 8 th 178thMonterey81st 208th 74th 184th182nd 166thDayton 193rd127th 177thCamas129th 155th59th131st 130th 54th 88th 4 th 69th 18th 1st Private 152nd170th 5th 76th Access102nd70th 77th92nd 126th 161st 105th128th175th 187th 112thAccess115th 102nd 162nd57th57th9th 170th79thQueen6th83rd 193rd 154th PrivateRedmond35th 116th169th103rd154thMeadow23rd13 0t h181stPierce133rd121st 105th144th86th 10th 22n d 67 th 141st140th71st3rd 173rd 116th 199th 113th 184th199th 137th71stAnacortes 104t hHarrington1st132nd2nd 151st139thPrivate 81st58th206th Glenwood80th114th147th177th Burnett117thPedestrian Private Minkler 1 0 4th 140th7th 110th2nd 135th 186th 94t hPrivate165th Access73rd61st Shattuck14 3rd 135th 180th 101st68th152nd 175t h147t hPedestrian 196th Access4th WellsMain9th 100th 98thP riva te138th 168th 4th 124th171st 106t h2 3 rd 10th 77t h141st 37th 65th 170th Private146th7th 138th209th 128t h119th4th 113th184th I-5 173rd 202nd PrivatePrivate75th 12 7t hGreen River 123rd 161st143rd 128th18th 3rd72nd Pasco83rd64th157thPrivateBurnett130th 136th 1st Private160th165th130th92nd 165th168th 121stLake Youngs Trail151st 165thPrivate 179th135t h118th145th 198thI-5164th121stPrivate175th 3rd 8th Pelly78t hHouser26th 178thIn d ex Jones150thPrivate 117th 141st70th185th21st 106th 136th 113th111th149th 169th120th84th176th 191st 5th 158thPrivate 169th126th 143rd 109th170th134th 5th120th I-5 192ndBlaine 3rd200th 160th200th 134th 78th69th5thLind12th 202nd 206th Private 62nd17th92nd 124th132ndRaymond151st103rd 66th 146th70th 184th 156th1st 150th 87th 3rd 177th102ndAccess Private 157th Private 8th 32nd Green River 171st181st 125th174th57th141stPri v at eDayton112th 189th 133rd 134th 175th 21st 71st Private72nd160th3rd 119th 77th27th119th 204th 126th 3 rd Access 118th141st 6th 4th 23rd 123rdLind190th 4 th Access 87th SR 51583rd1st 198th 164th 7th 7th 143r d75th 18thSR 515Access 135t h150th130th52nd68thPrivate 6th 119th Cedar6th 129thStevens143rd9th 29th 86th Jones99th 202nd 146thJefferson2nd 144th Index157 th 172nd 2nd 1 20th78th 160th Private124th 1 6th 180th122nd 70thPrivate 76th 185th Kent Boeing Morris5th 141st 169th161st 1 19th 21st Access Access36th 111th4 th 77th Unn a m ed 1 4 3rd 20th 66th149th56th1 91s tPrivate AccessPrivate 43rd 160thPierce156th129th Interurban179th 169th173rd 1st 15th 124th67th 156th1 1 8th 121stElma71st114th 24th 90th121st131st74th 68th 28th 32nd 154th180th 130th 181st 185th 156thPrivate71st 157th170th 98th Private 142nd2 0 4th 165th114th 17th Private105th4th 134th 182nd 120th Jones126th21st Pedestrian181st188th 1 85 th20thPowell 183rd178th Jericho136th190th Parkside163rdAccess 2nd 143rd 167th 188th 20th56th 91st 176th 164th172nd174th 136th 171st6 6th 11th129thAberdeen Access100th172nd 116th 155th190th55th Sunset 64th132nd166th 135th125th56th184th66th 131st13th Private 152nd204th 149th152nd59th80thAccess122nd124th 204th 184th113th113th 27th67th 127t h199th 148th 23rd 147th152nd 105th10th 163rd6th 27th 2nd 202nd 5th 162ndAc c es s 4th 72nd 164th 168th83rd 133rd20th 148th138th59th118th4th127th Pedestrian 139th 4th57th 143rd138th190th114th21st 122nd 170th Interurban 8th 173rd 180th Private 66th124th 115th1 6th 19th81st26thCamas 65th 134th 192ndAndover 161st 39th Access 177th65th180th88th Edmonds Private 28th 84th110th106th122nd4th123rd118th Elma27th 168th148thPrivate 160t h27th 172nd 120th 1st 7th 85th186th 1 6th 160thPrivate 126th 189th 116th Maple122nd208th 196th54th 141st165th123rd21st Private 166th62nd 7 6 th 6th 172nd 178th85th67th 6th 187th Access 25th Private103rd196thPrivate 10th A cc es sHazel 174th 140th 27th 31st 124th 146thBenson180th86th Private 158th 184th 1 2 8th 133rd194th In dex Lyons6th 168th132nd149th 110t h80th 148th190th 112th Access Williams178th 66 th 126th74th189th 106th66th96t h136th164th78th 145th 19 6 thPrivate171st 145thAccess 190th 75th1 4 3r d78th 127thHigh144th Private165th 188th 29th 8th80th 174th72nd 2nd 37th56th 111th164th68thPark133rd150th23rd Private 77th 126th 184th 133rd 117th10th Access 148th184thLake9th 192nd 120thRyan Access 164th132nd 85th 122nd120th Olympia5th 125th Smithers36th 2nd ThomasMont erey175th 72nd152ndMil l171st 65th 144thLangston 87th200th 117th 1 31 st 160th 67th 5th 37th 66th 131st 13th Blaine43rd 167th AccessAccess May Valley56th 82ndPrivate 142nd 120th 1st 20th 194th 4th PrivateAccess30th 16th 172nd 137th 7th 182nd Private145th 190th 92nd85th76th 131st 190th 125th7th 199th80th135th 78thHazelwood Davis82nd164th 179th 4th 76th 126thDayton120th 118th149th 166th154th172nd 6 8th 69th40th 1 46th115th82nd 184th116th75th1 23r d5th 91st Private3rd AccessIndexLake96th 159th 196th 156th1 36th 159thPrivate132nd158th76th32nd 109th81st 117th98th 180th 25th 160th 2ndMill 128t h110th 80th110th 162nd 142n d Private56th24th 172nd158th140th 167th Access 193rd Ch ela n 203rdAccess 163rd 1st Pedestrian 162nd 169th82nd 158thHouser186th 57th 201st 65th 196th 7th Access114t h204th 22nd Access10th Private RentonPark18th57th85th10th84th 23rd55th 158thShattuck160thGrant5th J o ne s 120th4th 9th 143rd98th113th77th6 th 132nd66th 61st124th201stAccess 132nd Ac ce ss Access108thPrivate 166th 184th I-405 198th 2n d 89th158th76th54th81st126th155th 136th64th Access 116th19th 58th160th 76th 160thAccess166th157thTacomaJonesAccess 3rd 108th Ma ple 2 1s t7th 126th167th 6th 10th Private5th 8th 71st 26th Private 194th 144thPrivate 129th Privat e8 thGarde n 20th Access128th62nd82nd 185th 6th 12th 143rd 114th CedarPrivate71st116th62nd3rd 128th59th7th Access Access Private120th 139th 92nd174thPri vat e96th14th Cedar1 72n d 199th56th138th66th 164th170thSunset 130th7th 168th 9th 10th 182nd 157th Access 118th 3rd 176th 96th182nd 25th 138thAccess 100th 187th 24th 16th 149th 123rd 1 59th May Creek Coal Creek Unnamed Ma dsen C re ek Springbrook CreekCoal Creek Tributary UnnamedU nn a me d Coal CreekUnnamedUnnamedUnnamed UnnamedUnnamedU n na medUnnamedKing County Kent Tukwila Newcastle Seattle Bellevue King County Mercer Island King County King County SeaTac King County King County King County King County Kent Renton City Limits Potential Annexation AreaBasinsBlack River Duamish Lake Washington East Lake Washington West Lower Cedar River May CreekSoos Creek ´ Surface Water UtilityComprehensive PlanPrinted 10/16/2009 Basin Locations 0 10.5 Miles Figure 6 - Drainage Basin Map Project Location - Black River Basin XΔSSxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxS WxWxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxZONEAESDxSDxSDxSDxSDxSDxSDx S D xSDxS Wx SDxSDxSDxSDxWxWxWxWx201819212115201617181921 202120181921 WETLAND APOND B100 YEARFLOODPLAINELEVATIONLOT LINEADJUSTMENTFOR SOUNDERSHEADQUARTERSUNDER FIELD FLOODMITIGATION STORAGEFLOOD MITIGATIONDISCHARGELOCATIONUNDER FIELD FLOODMITIGATION STORAGEUNDER FIELD FLOODMITIGATION STORAGENEWELEVATEDPATIOUNDER FIELDPERFORATEDDRAINAGE (TYP)BIOPOD STORMWATERTREATMENT FACILITYFLOODMITIGATIONDISCHARGELOCATIONSITESTORMWATERDISCHARGELOCATIONNEW STORAGEFACILITYPervious: 183,743 SF (4.22 ac) (Includes 50% of area.) NPGIS: 30,500 SF (0.70 ac) PGIS: 358,438 SF (8.23 ac) (Includes 50% of area.) 235,519 SF (5.31 AC) Calculated as 50% Pervious & 50% ImperviousLegendSCALE 1"=100'Proposed ConditionsFIGURE 7Natural Grass FieldTurf Field XΔSSxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxS WxWxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxZONEAESDxSDxSDxSDxSDxSDxSDx S D xSDxS Wx SDxSDxSDxSDxWxWxWxWx201819212115201617181921 202120181921 WETLAND APOND B100 YEARFLOODPLAINELEVATIONLOT LINEADJUSTMENTFOR SOUNDERSHEADQUARTERSUNDER FIELD FLOODMITIGATION STORAGEFLOOD MITIGATIONDISCHARGELOCATIONUNDER FIELD FLOODMITIGATION STORAGEUNDER FIELD FLOODMITIGATION STORAGENEWELEVATEDPATIOUNDER FIELDPERFORATEDDRAINAGE (TYP)BIOPOD STORMWATERTREATMENT FACILITYFLOODMITIGATIONDISCHARGELOCATIONSITESTORMWATERDISCHARGELOCATIONNEW STORAGEFACILITYNatural Grass (Pervious): 117,760 SF (2.70 ac) (Includes 50% of natural grass area.) Natural Grass (PGIS): 117,760 SF (2.70 ac) (Includes 50% of natural grass area.) Concrete Pathway, Roof (NPGIS): 32,438 SF (0.75 ac) Artificial Turf (PGIS): 211,421 SF (4.85 ac)Total PGIS: 329,181 SF (7.56 ac)Total NPGIS: 32,438 SF (0.74 ac)Total Pervious: 117,760 SF (2.70 ac)LegendSCALE 1"=100'Proposed Conditions (Water Quality Treatment)FIGURE 7bNatural Grass FieldTurf Field Project Location Figure 8 - Flow Control FIGURE 9 - FEMA Firm Map 144,44824075 Downstream Analysis This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes 08/01/2022 Legend 16371 0 8185 1637 1 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Labels City and County Boundary <all other values> Renton Streets Waterbodies Project Location Black River Duwamish River Elliot Bay Lake Washington Figure 10 - Downstream Analysis LEGEND Drainage Complaints Project Location - No Drainage Complaints Figure 11 - Drainage Complaints Treatment Flow Rate* 91st % Storm WQ Q 1.3192 cfs (Determined from WWHM) k Factor 1.91 Treatment Flow Rate 2.52 cfs (City of Renton/KC factor) 2 Year Flow Rate 3.183044cfs (Determined from WWHM) *Per SEPA requirements use larger of Renton with k factor or 2 year flow rate. Bioscape Media Filtration Rate 175 in/hr 14.58 ft/hr 0.0041 ft/sec 100 in/hr 8.33 ft/hr 0.0023 ft/sec Bioscape Area Required (Enhanced Basic)785.8sf 0.0188 (Phosphorus)1429.5 sf 0.0328 Area Provided 825 sf 0.0189 Sounders - Longacres Phosphorus Enhanced Basic Stormwater - Water Quality Calculations Figure 11 - Drainage ComplaintsFigure 11 - Drainage Complaints Figure 12 - Bioscape Sizing Treatment Flow Rate* 91st % Storm WQ Q 1.3192 cfs (Determined from WWHM) k Factor 1.91 Treatment Flow Rate 2.52 cfs (City of Renton/KC factor) 2 Year Flow Rate 3.183044 cfs (Determined from WWHM) *Per SEPA requirements use larger of Renton with k factor or 2 year flow rate. Bioscape Media Filtration Rate 175 in/hr 14.58 ft/hr 0.0041 ft/sec 100 in/hr 8.33 ft/hr 0.0023 ft/sec Bioscape Area Required (Enhanced Basic)785.8 sf 0.0180 (Phosphorus)1375.1 sf 0.0316 Area Provided 825 sf 0.0189 Phosphorus Enhanced Basic CITY OF RENTON SURFACE WATER DESIGN MANUAL 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-B-1 REFERENCE 8-B OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE CITY OF RENTON SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: Subbasin Name: Subbasin Number: Date Symbol Drainage Component Type, Name, and Size Drainage Component Description Slope Distance from Site Discharge Existing Problems Potential Problems Observations of Field Inspector, Resource Reviewer, or Resident See map Type: sheet flow, swale, stream, channel, pipe, pond, flow control/ treatment/on-site BMP/facility Size: diameter, surface area drainage basin, vegetation, cover, depth, type of sensitive area, volume % ¼ ml = 1,320 ft. Constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion Tributary area, likelihood of problem, overflow pathways, potential impacts Black River Drainage Basin Longacres Pond B Basin 1 11/02/22 Pond B Detention Pond 0%Within Flood Zone Within Flood Zone Tributary area is turf and natural grass. Flooding is mitigated with the use of underground storage facilities. A B C D 400' Within Flood Zone Within Flood Zone(2) 24"Public Storm Main Ductile Iron 0%200' Pond A Detention Pond 0%Within Flood Zone Within Flood Zone790' Conveyance Swale Open Channel 0%672' E 48" Public Storm Main Ductile Iron 1%545' F Black River Channel Open Channel 0%2673' FIGURE 13a 9,0281505 Longacres-Sounders-Downstream Analysis This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. WGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 11/2/2022 Legend 1023 512 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet1023 Information Technology - GIS 0 Pump Station Discharge Point Surface Water Main Culvert Open Drains Facility Outline Private Pump Station Private Discharge Point Private Pipe Private Culvert Private Open Drains Private Facility Outline Facility Transfer Streets Parks Waterbodies 2021.sid Red: Band_1 Green: Band_2 Blue: Band_37,256 .8 f t 400.0 ft199.6 ft790.0 ft671.2 ft 544.8 ft572.9 ft822.3 f t1,210.1 ft9 3 5 . 7 f t663.9 f t446.4 f t Project Discharge Point 1 Mile Downstream (A) Pond B (B) Public Storm Main (C) Pond A (D) Open Channel (E) Public Storm Main (F) Black River Channel Project Location FIGURE 13b 30 u) wU 0NN z N 3a IoN0oto 0 o C Z 3'- 0 3' -6" 3' -0" 4' -6" J nI1TC l I 10' -6" 4) I 00I i B 1C(D)8011C(D)801 A I I rn ICTDT66I 187uu IoD..._ vl 0ki FLOOR Boxmo DETAIL gelu 1/4 U U Y wO d ° a 4 Q a J WALLS DURING CONSTRUCTION OF VAULT. z W Q U hW- W tip w O w REINFORCING PER 2. PIPES ENTERING AND EXITING VAULT SHALL yNWZ U Lil N F- z d a mv Qf Q WQ= OPERATING NUT HAVE A PIPE JOINT LOCATED OUTSIDE THEFORCLARITY Q 0 YZw SPOOL STEM BUSHING IL J - VAULT WITHIN DISTANCE NO GREATER THAN LOzw Z as Z w C) U) O DETAIL 3 1/2 THE PIPE DIAMETER L wCory HIGH WATER EL 11.5 a J D EXTEND OPENING AS ab cn F 5 REQUIRED TO ACCOMMODATE a a RANGE (EL 8.00 TO EL 9.75) z STEM AND LIFT ASSEMBLY LIFTING STRAP NON- RISING STEM DESIGN EL- =8.50 o aNo rno-o 000 ZG `Eo J SV6 AND SV7 4 ° 3 va Z a4 uY EL. 10.0 pa d VALVE GLAND C z 6 m'EE E Vl u0m 1r, WIPER GASKET 8, so a e 0 S d Z GATE SV1 -SV4 60 "0 INLET SV8 d Ln s EL. 8.50 PIPE JOINT U a m z m e NOTE 2 EL. 7.60 aa n a 30 u) wU 0NN z N 3a IoN0oto 0 o C Z 3'- 0 3' -6" 3' -0" 4' -6" J nI1TC l I 10' -6" 4) I 00I i B 1C(D)8011C(D)801 36 0 DI SPOOL (FLxFL) 36 "0 STEEL SPOOL (FLxPE) WITH SEEP RING1d 60" SLUICE I EL. 5.56 36"0 DI BASE BEND (FLxFL) GATE I PIPE JOINT NOTE 2 I I I 1C(D) O21 C )802 IE = 1.75 I I I im IF= 1.5 EL = 1.0 - - - - - -- 24 "0 OUTFALL SHIM AND GROUT BASE PLATE ANCHORED AS REQUIRED W/ (4) 7/8 "0 ADHESIVE ANCHORS, MIN 6 5/8" SECTION EMBEDMENT 12 "6" 0 1' 2' 3' 4' S' IC(D 801 1C(D)801 Ar it V. ° r REMOVABLE TOP SLAB 7m. I. A ICTDT66I 187uu IoD..._ FLOOR Box NOTES: DETAIL PLAN BELOW TOP SLAB K, l N 1/4 1. ALL PIPES SHALL BE CAST INTO VAULT IC(D 27 IC(D)801 d ° a 4 a WALLS DURING CONSTRUCTION OF VAULT. NOTE: 4 REINFORCING PER 2. PIPES ENTERING AND EXITING VAULT SHALLLADDERSOMITTEDd a BUSHED FLOOR BOX TOP SLAB OPERATING NUT HAVE A PIPE JOINT LOCATED OUTSIDE THEFORCLARITY SPOOL STEM BUSHING VAULT WITHIN DISTANCE NO GREATER THAN Z TYP 2 DETAIL 3 1/2 THE PIPE DIAMETER 36 "0 TELESCOPING VALVE (NRS) HIGH WATER EL 11.5 9C(D 01 1C )801 EXTEND OPENING AS LENGTH = 2' -5" REQUIRED TO ACCOMMODATE RECORD DRAWING INFORMATION COMPILED RANGE (EL 8.00 TO EL 9.75) STEM AND LIFT ASSEMBLY LIFTING STRAP NON- RISING STEM DESIGN EL- =8.50 PER GATE VALVE MANUFACTURER IS NOT RESPONSIBLE FOR ACCURACY OR COMPLETENESS OF CONTRACTOR'S RECORDS. i•iiiis _iip®®ii®iii® NOTE: FIELD LOCATE j RECORD DRAWIiNG' FLOOR BOX CENTERED SV6 AND SV7 4 ° ABOVE STEM. EL. 10.0 FLOOR BOX 2 d VALVE GLAND RECOMMENDED ev 24 "0 CANAL WIPER GASKET d GATE SV1 -SV4 60 "0 INLET SV8 d EL. 8.50 PIPE JOINT e NOTE 2 EL. 7.60 36 0 DI SPOOL (FLxFL) 36 "0 STEEL SPOOL (FLxPE) WITH SEEP RING1d 60" SLUICE I EL. 5.56 36"0 DI BASE BEND (FLxFL) GATE I PIPE JOINT NOTE 2 I I I 1 C(D) O21 C )802 IE = 1.75 I I I im IF= 1.5 EL = 1.0 - - - - - -- 24 "0 OUTFALL SHIM AND GROUT BASE PLATE ANCHORED AS REQUIRED W/ (4) 7/8 "0 ADHESIVE ANCHORS, MIN 6 5/8" SECTION EMBEDMENT 12 "6" 0 1' 2' 3' 4' S' IC(D 801 1C(D)801 Ar it V. ° r REMOVABLE TOP SLAB 7m. I. 12" 6" 0 1' 2' FOR APPROVAL BY BY w -47 - 2 7'r ® DOLL # 167 LESCOPING NRS), RANGE 0 -9.7' (TYP) EL. =8.50 ID SV7 I SPOOL (FLxFL) I BASE FLxFL) 71'e k,57 SCANNED OCT 4 2000 A IC(D 801 1C(D)801 DETAIL PLAN BELOW TOP SLAB K, l N 1/4 8 STEEL PLATE IC(D 27 IC(D)801 12 "6" 0 1 2' 3' 4' 5' REINFORCING PER a STRUCTURAL PLANS BUSHED FLOOR BOX TOP SLAB OPERATING NUT WALL OF PIPE SPOOL STEM BUSHING Z DETAIL 3 SCALE: NONE 1C(D)802 1C EXTEND OPENING AS REQUIRED TO ACCOMMODATE RECORD DRAWING INFORMATION COMPILED STEM AND LIFT ASSEMBLY FROM CONTRACTOR'S RECORDS. LICENSEE NON- RISING STEM PER GATE VALVE MANUFACTURER IS NOT RESPONSIBLE FOR ACCURACY OR COMPLETENESS OF CONTRACTOR'S RECORDS. i•iiiis _iip®®ii®iii® NOTE: FIELD LOCATE j RECORD DRAWIiNG' FLOOR BOX CENTERED ABOVE STEM. DETAIL FLOOR BOX 2 t t iC(D 801 1C(D)801 RECOMMENDED ev 12" 6" 0 1' 2' FOR APPROVAL BY BY w -47 - 2 7'r ® DOLL # 167 LESCOPING NRS), RANGE 0 -9.7' (TYP) EL. =8.50 ID SV7 I SPOOL (FLxFL) I BASE FLxFL) 71'e k,57 SCANNED OCT 4 2000 FIGURE 14.A Pond B Flow Control Facility FIGURE 14B Pond B 24" Outfall UB 7A7..2....11.1 1tb B.-3 r,..t..k0VPROJECTSITE SCALE: NONE SPRINGB ••K CREEK 1,',, 1;..,, A._•__ ii-_,,,,, 1 N:=.-.- A- wmo-‘u--- w• v-: i' ee-" n, l. f.''.'--.'!'14'0ri4-0‘-L1 I1' 12111' 1•-'' 1..,,''.,,,,,* i.,)` - n11rp."4• m. v-.- 4.•• a 1tk:• i„, r=.., 47... k..-.,1L.. 4. 6'4:..14-:),- 44-:•.-.*',:. b.*i*- VNt0N 0_"__,,.__e._'-_a__•.c_"c_a5_-2.m-..i1.. 3. i1e11:rlf;.7* l.se4' 2-; BASIN 5- 4 %'- P 7ar.1. r‘.. 1.— t.:t11t'1T.711. 1111-111. i10r167t`,v1*_.; 1'11: 7i ,. , 4Iiillm_.! , i ii a,... - a --"-•-- -- -- ----'- Ih"---...111"41- 16ZA.---- 11,,t:, i."1-itEril.1 \,,-...-,.,, 2. . ,. . 774I 1 1,= * ' ' .--•-•-•- '''' A ...All*L VII t ' '--. 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'4 .••7---\...,sw 16th ST 1 2_ -• -!ii 0 \Ilk ,,,T,,,....i., ,..,,,,, , .... ---_,:•----___ -----1,1 .,, _ _ tifi ,, Jo i ';41: " l' ii r i 41,s DI\adffr --_____ ..,,, ...i.7,77---.....:....--_,...-....,1,0:-,-,..--:.4.,,,,,,1„0:,- r,... .:.._,....,... •_,..11 __. / 1 r-1, obi: ,,,'..,';',4; :41' Iiiii - I; T 11:--. 111111111111111g: I i.al , _....iiima......_.....--,_-,-- --5...................."'"-- 7- -......-,..:•07.0' \."2„..,sihi.,___I 1,4 jj ;1 1, 1iv,.4.0„;,,,,, -.,•;.....sap,- f r...."--.-.-....-4,•------ I -- if 14 -r" IT 41 4, Tail NLARGEMINT OF CSTC - imi'rniiii__ jika".$1SITESOILGROUPSviiTLANDANDDETENTION'1/4. . .mm0. ,„_,,..„ 1 ff 1.COMBINED WE TPOND/ j ''DETENTION POND i 4.-_,..m.,........ki• 1„..,,,,..-rid1111...' ----.0a, c.',,,,------iin ' -......-r---- .---- 4...... - gtial —r- 2'.-UR - URBAN LAND ir''.t.--+-1-'17,7: •,,..,•,, P_ C‘_ ..‘ Iv 11"."111'....".-1 1 .71 WO - WOODINVILLE SILT LOAM \ I- A PY - PUYALLUP FINE SANDY LOA` '1 : -:----- 1 V' II --ipNG - NEWBERG SILT LOAM 71',• .T.-- , , 0 glormi0*W r.,, - i -- UPRR e II 1 i s \\ ...._._ kVD i f 111111r--"-"-*/1 ilM•VI;A U R go 1IIJulke.,,'-"' .2•01,..„IA 1r aci , linagrill Dc3i ii, ..... Joy— 74IPiiiliII , '01-11 g . 11 am En t _-,1-'"----,, „...ad 6,.. L.+. 00 MB lit MIM:I4 4"'.:;,'•,4 M'.::...•!,E,, 4 1l117 MUM NSea i-rt-5r.. i- c-1n1t95f1 Y141G Ag '' N GREEN RIVER Aculurr iMSCIINIvNI/m1e1-er.mdINrCmuo.m sitravaL walim .1m1P05T-CIEVELOPIABIT DRAINAGE BASINSgaire3Z• MtlagEPP=AMISS REPORT FIG. C.1ei_AmerirAvar• IMMO VI INIPL re sass Nan SURFACE WATER MANAGEMENT ROM PROJECT mai. 014002 IllIsinums 1imoOSIERROMLoamof=PA Sounders Project FIGURE 14C Longacres Existing Drainage Basins 1 September 2019 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS), ENHANCED, PHOSPHORUS & OIL TREATMENT For Contech Engineered Solutions Filterra® BioscapeTM Ecology’s Decision: Based on Contech’s submissions, including the Final Technical Evaluation Reports, dated August 2019, March, 2014, December 2009 and additional information provided to Ecology, Ecology hereby issues the following use level designations: 1. A General Use Level Designation for Basic, Enhanced, Phosphorus, and Oil Treatment for the Filterra® Bioscape System constructed with a minimum media thickness of 21 inches (1.75 feet), at the following water quality design hydraulic loading rates: Treatment Infiltration Rate (in/hr) for use in BMP Sizing Basic 175 Phosphorus 100 Oil 50 Enhanced 175 2. The Filterra® BioscapeTM unit is not appropriate for oil spill-control purposes. 3. Ecology approves the Filterra® BioscapeTM units for treatment at the hydraulic loading rates listed above, to achieve the maximum water quality design flow rate. Calculate the water quality design flow rates using the following procedures:  Western Washington: for treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using the latest version of the Western Washington Hydrology Model or other Ecology-approved continuous runoff model.  Eastern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using one of the three flow rate based methods described in Chapter 2.2.5 of the Stormwater Management Manual for Eastern Washington (SWMMEW) or local manual.  Entire State: For treatment installed downstream of detention, the water quality design flow rate is the full 2-year release rate of the detention facility. FIGURE 15 2 4. This General Use Level Designation has no expiration date but Ecology may revoke or amend the designation, and is subject to the conditions specified below. Ecology’s Conditions of Use: Filterra Bioscape systems shall comply with the following conditions: 1. Design, assemble, install, operate, and maintain the Filterra Bioscape systems in accordance with applicable Contech Filterra manuals, document, and the Ecology Decision. 2. The minimum size filter surface-area for use in Washington is determined by using the design water quality flow rate (as determined in this Ecology Decision, Item 3, above) and the Infiltration Rate from the table above (use the lowest applicable Infiltration Rate depending on the level of treatment required). Calculate the required area by dividing the water quality design flow rate (cu-ft/sec) by the Infiltration Rate (converted to ft/sec) to obtain required surface area (sq-ft) of the Filterra unit. 3. Each site plan must undergo Contech Filterra review before Ecology can approve the unit for site installation. This will ensure that design parameters including site grading and slope are appropriate for use of a Filterra Bioscape unit. 4. Filterra Bioscape media shall conform to the specifications submitted to and approved by Ecology and shall be sourced from Contech Engineered Solutions, LLC with no substitutions. 5. Maintenance includes removing trash, degraded mulch, and accumulated debris from the filter surface and replacing the mulch layer. Use inspections to determine the site-specific maintenance schedules and requirements. Follow maintenance procedures given in the most recent version of the Filterra® BioscapeTM Operation and Maintenance Manual. 6. Maintenance: The required maintenance interval for stormwater treatment devices is often dependent upon the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a “one size fits all” maintenance cycle for a particular model/size of manufactured filter treatment device.  Contech designs Filterra systems for a target maintenance interval of 6 months in the Pacific Northwest. Maintenance includes removing and replacing the mulch layer above the media along with accumulated sediment, trash, and captured organic materials therein, evaluating plant health, and pruning the plant if deemed necessary.  Conduct maintenance following manufacturer’s guidelines. 7. BioscapeTM systems may or may not utilize an underdrain. Bioscape systems without an underdrain shall be designed with a temporary water storage area beneath the treatment media to provide a detention reservoir. Water shall not saturate the treatment media at any time 8. The distance from the point of entry of water to the most distant point on the surface of the Filterra Bioscape treatment media shall not exceed 12-feet. The Filterra Bioscape requires water to flow across the entire surface area to obtain optimal performance. 3 9. Install the Filterra Bioscape in such a manner that flows exceeding the maximum Filterra operating rate are conveyed around the Filterra Bioscape mulch and media and will not resuspend captured sediment. 10. Discharges from the Filterra® units shall not cause or contribute to water quality standards violations in receiving waters. Applicant: Contech Engineered Solutions, LLC. Applicant’s Address: 11815 NE Glenn Widing Drive Portland, OR 97220 Application Documents:  State of Washington Department of Ecology Application for Conditional Use Designation, Americast (September 2006)  Quality Assurance Project Plan Filterra® Bioretention Filtration System Performance Monitoring, Americast (April 2008)  Quality Assurance Project Plan Addendum Filterra® Bioretention Filtration System Performance Monitoring, Americast (June 2008)  Draft Technical Evaluation Report Filterra® Bioretention Filtration System Performance Monitoring, Americast (August 2009)  Final Technical Evaluation Report Filterra® Bioretention Filtration System Performance Monitoring, Americast (December 2009)  Technical Evaluation Report Appendices Filterra® Bioretention Filtration System Performance Monitoring, Americast (August 2009)  Memorandum to Department of Ecology Dated October 9, 2009 from Americast, Inc. and Herrera Environmental Consultants  Quality Assurance Project Plan Filterra® Bioretention System Phosphorus treatment and Supplemental Basic and Enhanced Treatment Performance Monitoring, Americast (November 2011)  Filterra® letter August 24, 2012 regarding sizing for the Filterra® Shallow System.  University of Virginia Engineering Department Memo by Joanna Crowe Curran, Ph. D dated March 16, 2013 concerning capacity analysis of Filterra® internal weir inlet tray.  Filterra® BioscapeTM Bioretention System Model Configuration Approval Request, January 2014  Terraphase Engineering letter to Jodi Mills, P.E. dated April 2, 2013 regarding Terraflume Hydraulic Test, Filterra® Bioretention System and attachments.  Technical Evaluation Report, Filterra® System Phosphorus Treatment and Supplemental Basic Treatment Performance Monitoring. March 27th, 2014.  State of Washington Department of Ecology Application for Conditional Use Level Designation, Contech Engineered Solutions (May 2015)  Quality Assurance Project Plan Filterra® Bioretention System, Contech Engineered Solutions (May 2015)  Filterra Bioretention System Armco Avenue General Use Level Designation Technical Evaluation Report, Contech Engineered Solutions (August 2019) 4 Applicant’s Use Level Request: General Level Use Designation for Basic, Enhanced, Phosphorus, and Oil Treatment. Applicant’s Performance Claims: Field-testing and laboratory testing show that the Filterra® unit is promising as a stormwater treatment best management practice and can meet Ecology’s performance goals for basic, enhanced, phosphorus, and oil treatment. Findings of Fact: Field Testing 2015-2019 1. Contech completed field testing of a 4 ft. x 4 ft. Filterra® unit at one site in Hillsboro, Oregon from September 2015 to July 2019. Throughout the monitoring period a total of 24 individual storm events were sampled, of which 23 qualified for TAPE sampling criteria. 2. Contech encountered several unanticipated events and challenges that prevented them from collecting continuous flow and rainfall data. An analysis of the flow data from the sampled events, including both the qualifying and non-qualifying events, demonstrated the system treated over 99 % of the influent flows. Peak flows during these events ranged from 25 % to 250 % of the design flow rate of 29 gallons per minute. 3. Of the 23 TAPE qualified sample events, 13 met requirements for TSS analysis. Influent concentrations ranged from 20.8 mg/L to 83 mg/L, with a mean concentration of 46.3 mg/L. The UCL95 mean effluent concentration was 15.9 mg/L, meeting the 20 mg/L performance goal for Basic Treatment. 4. All 23 TAPE qualified sample events met requirements for dissolved zinc analysis. Influent concentrations range from 0.0384 mg/L to 0.2680 mg/L, with a mean concentration of 0.0807 mg/L. The LCL 95 mean percent removal was 62.9 %, meeting the 60 % performance goal for Enhanced Treatment. 5. Thirteen of the 23 TAPE qualified sample events met requirements for dissolved copper analysis. Influent concentrations ranged from 0.00543 mg/L to 0.01660 mg/L, with a mean concentration of 0.0103 mg/L. The LCL 95 mean percent removal was 41.2 %, meeting the 30 % performance goal for Enhanced Treatment. 6. Total zinc concentrations were analyzed for all 24 sample events. Influent EMCs for total zinc ranged from 0.048 mg/L to 5.290 mg/L with a median of 0.162 mg/L. Corresponding effluent EMCs for total zinc ranged from 0.015 mg/L to 0.067 mg/L with a median of 0.029 mg/L. Total event loadings for the study for total zinc were 316.85 g at the influent and 12.92 g at the effluent sampling location, resulting in a summation of loads removal efficiency of 95.9 %. 7. Total copper concentrations were analyzed for all 24 sample events. Influent EMCs for 5 total copper ranged from 0.003 mg/L to 35.600 mg/L with a median value of 0.043 mg/L. Corresponding effluent EMCs for total copper ranged from 0.002 mg/L to 0.015 mg/L with a median of 0.004 mg/L. Total event loadings for total copper for the study were 1,810.06 g at the influent and 1.90 g at the effluent sampling location, resulting in a summation of loads removal efficiency of 99.9 %. Field Testing 2013 1. Filterra® completed field-testing of a 6.5 ft x 4 ft. unit at one site in Bellingham, Washington. Continuous flow and rainfall data collected from January 1, 2013 through July 23, 2013 indicated that 59 storm events occurred. The monitoring obtained water quality data from 22 storm events. Not all the sampled storms produced information that met TAPE criteria for storm and/or water quality data. 2. The system treated 98.9 percent of the total 8-month runoff volume during the testing period. Consequently, the system achieved the goal of treating 91 percent of the volume from the site. Stormwater runoff bypassed during four of the 59 storm events. 3. Of the 22 sampled events, 18 qualified for TSS analysis (influent TSS concentrations ranged from 25 to 138 mg/L). The data were segregated into sample pairs with influent concentration greater than and less than 100 mg/L. The UCL95 mean effluent concentration for the data with influent less than 100 mg/L was 5.2 mg/L, below the 20- mg/L threshold. Although the TAPE guidelines do not require an evaluation of TSS removal efficiency for influent concentrations below 100 mg/L, the mean TSS removal for these samples was 90.1 percent. Average removal of influent TSS concentrations greater than 100 mg/L (three events) was 85 percent. In addition, the system consistently exhibited TSS removal greater than 80 percent at flow rates at a 100 inches per hour [in/hr] infiltration rate and was observed at 150 in/hr. 4. Ten of the 22 sampled events qualified for TP analysis. Americast augmented the dataset using two sample pairs from previous monitoring at the site. Influent TP concentrations ranged from 0.11 to 0.52 mg/L. The mean TP removal for these twelve events was 72.6 percent. The LCL95 mean percent removal was 66.0, well above the TAPE requirement of 50 percent. Treatment above 50 percent was evident at 100 in/hr infiltration rate and as high as 150 in/hr. Consequently, the Filterra® test system met the TAPE Phosphorus Treatment goal at 100 in/hr. Influent ortho-P concentrations ranged from 0.005 to 0.012 mg/L; effluent ortho-P concentrations ranged from 0.005 to 0.013 mg/L. The reporting limit/resolution for the ortho-P test method is 0.01 mg/L, therefore the influent and effluent ortho-P concentrations were both at or near non-detect concentrations. Field Testing 2008-2009 1. Filterra® completed field-testing at two sites at the Port of Tacoma. Continuous flow and rainfall data collected during the 2008-2009 monitoring period indicated that 89 storm events occurred. The monitoring obtained water quality data from 27 storm events. Not all the sampled storms produced information that met TAPE criteria for storm and/or water quality data. 6 2. During the testing at the Port of Tacoma, 98.96 to 99.89 percent of the annual influent runoff volume passed through the POT1 and POT2 test systems respectively. Stormwater runoff bypassed the POT1 test system during nine storm events and bypassed the POT2 test system during one storm event. Bypass volumes ranged from 0.13% to 15.3% of the influent storm volume. Both test systems achieved the 91 percent water quality treatment-goal over the 1-year monitoring period. 3. Consultants observed infiltration rates as high as 133 in/hr during the various storms. Filterra® did not provide any paired data that identified percent removal of TSS, metals, oil, or phosphorus at an instantaneous observed flow rate. 4. The maximum storm average hydraulic loading rate associated with water quality data is <40 in/hr, with the majority of flow rates < 25 in/hr. The average instantaneous hydraulic loading rate ranged from 8.6 to 53 inches per hour. 5. The field data showed a removal rate greater than 80% for TSS with an influent concentration greater than 20 mg/l at an average instantaneous hydraulic loading rate up to 53 in/hr (average influent concentration of 28.8 mg/l, average effluent concentration of 4.3 mg/l). 6. The field data showed a removal rate generally greater than 54% for dissolved zinc at an average instantaneous hydraulic loading rate up to 60 in/hr and an average influent concentration of 0.266 mg/l (average effluent concentration of 0.115 mg/l). 7. The field data showed a removal rate generally greater than 40% for dissolved copper at an average instantaneous hydraulic loading rate up to 35 in/hr and an average influent concentration of 0.0070 mg/l (average effluent concentration of 0.0036 mg/l). 8. The field data showed an average removal rate of 93% for total petroleum hydrocarbon (TPH) at an average instantaneous hydraulic loading rate up to 53 in/hr and an average influent concentration of 52 mg/l (average effluent concentration of 2.3 mg/l). The data also shows achievement of less than 15 mg/l TPH for grab samples. Filterra® provided limited visible sheen data due to access limitations at the outlet monitoring location. 9. The field data showed low percentage removals of total phosphorus at all storm flows at an average influent concentration of 0.189 mg/l (average effluent concentration of 0.171 mg/l). We may relate the relatively poor treatment performance of the Filterra® system at this location to influent characteristics for total phosphorus that are unique to the Port of Tacoma site. It appears that the Filterra® system will not meet the 50 percent removal performance goal when you expect the majority of phosphorus in the runoff to be in the dissolved form. Laboratory Testing 1. Filterra® performed laboratory testing on a scaled down version of the Filterra® unit. The lab data showed an average removal from 83-91% for TSS with influents ranging from 21 to 320 mg/L, 82-84% for total copper with influents ranging from 0.94 to 2.3 mg/L, and 50-61% for orthophosphate with influents ranging from 2.46 to 14.37 mg/L. 2. Filterra® conducted permeability tests on the soil media. 7 3. Lab scale testing using Sil-Co-Sil 106 showed percent removals ranging from 70.1% to 95.5% with a median percent removal of 90.7%, for influent concentrations ranging from 8.3 to 260 mg/L. Filterra® ran these laboratory tests at an infiltration rate of 50 in/hr. 4. Supplemental lab testing conducted in September 2009 using Sil-Co-Sil 106 showed an average percent removal of 90.6%. These laboratory tests were run at infiltration rates ranging from 25 to 150 in/hr for influent concentrations ranging from 41.6 to 252.5 mg/l. Regression analysis results indicate that the Filterra® system’s TSS removal performance is independent of influent concentration in the concentration rage evaluated at hydraulic loading rates of up to 150 in/hr. Contact Information: Applicant: Jeremiah Lehman Contech Engineered Solutions, LLC. 11815 Glenn Widing Dr. Portland, OR 97220 (503) 258-3105 jlehman@conteches.com Applicant’s Website: http://www.conteches.com Ecology web link: http://www.ecy.wa.gov/programs/wq/stormwater/newtech/index.html Ecology: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360) 407-6444 douglas.howie@ecy.wa.gov Date Revision July 2014 GULD for Basic, Enhanced, Phosphorus and Oil granted March 2015 Revised Contact Information December 2015 Revised device name from Filterra® BoxlessTM to Filterra® BioscapeTM June 2016 Revised text regarding Hydraulic conductivity value November 2016 Changed Contech contact information September 2019 GULD for Basic and Enhanced at 175 in/hr infiltration rate Filterra Bioscape Owner’s Manual (No Precast Vault Provided) ENGINEERED SOLUTIONS This Owner’s Manual applies to Filterra Bioscape ONLY (Filterra installed directly into an excavated basin or other customer provided container, such as a large cast-in-place vault). ® ® www.ContechES.com/filterra | 800-338-1122 3 Table of Contents Introduction ................................................................................4 Activation Overview .....................................................................4 Filterra Plant Selection Overview ...................................................5 Warranty Overview ......................................................................5 Routine Maintenance Guidelines...................................................5 Plant Care ..................................................................................7 Maintenance Visit Procedure .........................................................8 Maintenance Checklist ...............................................................10 Appendix 1 – Activation Package ................................................11 ENGINEERED SOLUTIONS ® www.ContechES.com/filterra | 800-338-11224 Introduction Thank you for your purchase of the Filterra® Bioscape® System. Filterra® is a specially engineered stormwater treatment system incorporating high performance biofiltration media to remove pollutants from stormwater runoff. The system’s biota (vegetation and soil microorganisms) then further breakdown and absorb captured pollutants. All components of the system work together to provide a sustainable long-term solution for treating stormwater runoff. Included with your purchase is a Supervised Activation service as well as a 1-year warranty from delivery of the system. In some cases, a Final Site Assessment (assessment of unit condition, mulch replacement, debris removal and pruning) may also be included for systems smaller than 1000 sf in size. Check your order documentation for further information. Filterra® Bioscape® systems should not be activated until the site is stabilized to prevent construction related runoff from entering and contaminating the system. For Filterra® Bioscape® systems installed within an excavated basin, Contech provides an erosion control sock around the perimeter to provide an extra layer of protection. However, these protection devices are intended as a best practice and cannot fully prevent contamination. It is the purchaser’s responsibility to provide adequate measures to prevent construction related runoff from entering the Filterra® Bioscape® system. Design and Installation Each project presents different scopes for the use of Filterra® Bioscape® systems. Information and help may be provided to the design engineer during the planning process. Correct Filterra® Bioscape® sizing (by rainfall region) is essential to predict pollutant removal rates for a given area. The engineer shall submit calculations for approval by the local jurisdiction. The contractor is responsible for the correct installation of Filterra® Bioscape® systems as shown in approved plans. A comprehensive installation manual is available from Contech. Activation Overview Activation of the Filterra® Bioscape® system is a procedure completed by the contractor to place the system into working condition. This involves the following items: • Installation of the Filterra® Bioscape® underdrain system • Installation of the Filterra® media layer • Planting of the system’s vegetation • Placement of pretreatment mulch layer using mulch certified for use in Filterra® systems www.ContechES.com/filterra | 800-338-1122 5 Minimum Requirements The minimum requirements for Filterra® Bioscape®Activation are as follows: 1. The purchaser must have sourced vegetation meeting the requirements outlined in the Filterra® Bioscape® Activation Package 2. A pre-construction meeting is required to discuss site requirements, logistics planning and activation FAQ and red flags. 3. The site landscaping must be fully stabilized, i.e. full landscaping installed and some grass cover (not just straw and seed) is required to reduce sediment transport. Construction debris and materials should be removed from surrounding area. 4. Final paving must be completed. Final paving ensures that paving materials will not enter and contaminate the Filterra® system during the paving process, and that the plant will receive runoff from the drainage area, assisting with plant survival for the Filterra® system. 5. All immediate upstream and downstream structures should be placed with piping into the system already installed for connection during activation. An Activation Checklist is included in the Filterra® Bioscape® Activation Package to ensure proper conditions are met for Activation. A charge of $1500.00 will be invoiced for each Supervised Activation visit requested by Customer where Contech determines that the site does not meet the conditions required for Activation. Filterra Plant Selection Overview A Plant List is available on the Contech website highlighting recommended plants for Filterra® Bioscape® systems in your area. Keep in mind that plants are subject to availability due to seasonality. Plants installed in the Filterra® Bioscape® system shall be container-grown plants (max 15 gallon) from nursery stock and will be immature in height and spread at Activation. It is the responsibility of the owner to provide adequate irrigation when necessary to the plant of the Filterra® Bioscape® system. The “Filterra® Bioscape® Activation Package” document is included as an appendix and discusses proper selection of the plants within Filterra® Bioscape® systems. Warranty Overview Refer to the Contech® Engineered Solutions LLC Stormwater Treatment System LIMITED WARRANTY for further information. The following conditions may void the Filterra® Bioscape® system’s warranty and waive the manufacturer provided Final Site Assessment (if applicable): • Unauthorized activation or performance of any of the items listed in the activation overview without Contech supervision or input • Removal of any Filterra® system components • Failure to prevent construction related runoff from entering the Filterra® system • Failure to properly store and protect any Filterra® components (including media and underdrain stone) that are shipped separately to the site Routine Maintenance Guidelines With proper routine maintenance, the biofiltration media within the Filterra® Bioscape® system should last as long as traditional bioretention media. Routine maintenance can be provided by certified maintenance providers listed on the Contech website. Training can also be provided to other stormwater maintenance or landscape providers. www.ContechES.com/filterra | 800-338-11226 Why Maintain? All stormwater treatment systems require maintenance for effective operation. This necessity is often incorporated in your property’s permitting process as a legally binding BMP maintenance agreement. Other reasons to maintain are: • Avoiding legal challenges from your jurisdiction’s maintenance enforcement program. • Prolonging the expected lifespan of your Filterra® media. • Avoiding more costly media replacement. • Helping reduce pollutant loads leaving your property. Simple maintenance of the Filterra® Bioscape® is required to continue effective pollutant removal from stormwater runoff before discharge into downstream waters. This procedure will also extend the longevity of the living biofilter system. The unit will recycle and accumulate pollutants within the biomass, but is also subjected to other materials entering the inlet. This may include trash, silt and leaves etc. which will be contained above the mulch layer. Too much silt may inhibit the Filterra’s flow rate, which is the reason for site stabilization before activation. Regular replacement of the mulch stops accumulation of such sediment. When to Maintain? Maintenance visits are typically scheduled seasonally; the spring visit aims to clean up after winter loads including salts and sands while the fall visit helps the system by removing excessive leaf litter. It has been found that in regions which receive between 30-50 inches of annual rainfall, (2) two visits are generally recommended; In regions with less rainfall often only (1) one visit per annum is sufficient. Varying land uses can affect maintenance frequency; e.g. some fast food restaurants require more frequent trash removal. Contributing drainage areas which are subject to new development wherein the recommended erosion and sediment control measures have not been implemented may require additional maintenance visits. Some sites may be subjected to extreme sediment or trash loads, requiring more frequent maintenance visits. This is the reason for detailed notes of maintenance actions per unit, helping the Manufacturer and Owner predict future maintenance frequencies, reflecting individual site conditions. Owners must promptly notify the maintenance provider of any damage to the plant(s), which constitute(s) an integral part of the bioretention technology. Exclusion of Services Clean up due to major contamination such as oils, chemicals, toxic spills, etc. will result in additional costs and are not included as part of the Final Site Assessment (if applicable). Should a major contamination event occur the Owner must block off the outlet pipe of the Filterra® (where the cleaned runoff drains to, such as drop inlet) and block off the throat of the Filterra®. The Supplier should be informed immediately. Maintainenance Visit Summary Maintenance visits are typically scheduled seasonally; the spring visit aims to clean up after winter loads including salts and sands while the fall visit helps the system by removing excessive leaf litter. 1. Inspection of Filterra® Bioscape® and surrounding area 2. Removal of erosion control stones 3. Removal of debris, trash and mulch 4. Removal and disposal of erosion control sock from system perimeter (should be completed at 6 month or 12 month maintenance depending upon site characteristics). A new erosion control sock is no longer needed after the first year. 5. Mulch replacement 6. Plant health evaluation and pruning or replacement as necessary 7. Clean area around Filterra® 8. Complete paperwork www.ContechES.com/filterra | 800-338-1122 7 Plant Care for Filterra® Systems After Activation, the Contractor is responsible for proper care of the vegetation until the site is handed over to the Owner. After that, it is the Site Owner’s responsibility to care for the vegetation. Contech recommends the following care for the plants: 1. To prevent transplant shock (especially if planting takes place in the hot season), it may be necessary to prune some of the foliage to compensate for reduced root uptake capacity. This is accomplished by pruning away some of the smaller secondary branches or a main scaffold branch if there are too many. Too much foliage relative to the root ball can dehydrate and damage the plant. 2. Plant staking may be required. 3. With all trees/shrubs, remove dead, diseased, crossed/ rubbing, sharply crotched branches or branches growing excessively long or in wrong direction compared to majority of branches. 4. Contech recommends irrigation of the Filterra® Vegetation. The following guidance will help to ensure the vegetation is properly irrigated. Irrigation Recommendations: • Each Filterra® system must receive adequate irrigation to ensure survival of the living system during periods of drier weather. • Irrigation sources include rainfall runoff from downspouts and/or gutter flow, applied water through the tree grate or in some cases from an irrigation system with emitters installed during construction. • At Activation: Apply about one (cool climates) to two (warm climates) gallons of water per inch of trunk diameter over the root ball. • During Establishment: In common with all plants, each Filterra® plant will require more frequent watering during the establishment period. One inch of applied water per week for the first three months is recommended for cooler climates (2 to 3 inches for warmer climates). If the system is receiving rainfall runoff from the drainage area, then irrigation may not be needed. Inspection of the soil moisture content can be evaluated by gently brushing aside the mulch layer and feeling the soil. Be sure to replace the mulch when the assessment is complete. Irrigate as needed**. • Established Plants: Established plants have fully developed root systems and can access the entire water column in the media. Therefore irrigation is less frequent but requires more applied water when performed. For a mature system assume 3.5 inches of available water within the media matrix. Irrigation demand can be estimated as 1” of irrigation demand per week. Therefore if dry periods exceed 3 weeks, irrigation may be required. ** Five gallons per square yard approximates 1 inch of water. Therefore for a 6’ x 6 foot Filterra® approximately 20-60 gallons of applied water is needed. To ensure even distribution of water it needs to be evenly sprinkled over the entire surface of the filter bed, with special attention to make sure the root ball is completely wetted. NOTE: if needed, measure the time it takes to fill a five gallon bucket to estimate the applied water flow rate. Then calculate the time needed to irrigate the Filterra®, For example is the flow rate of the sprinkler is 5 gallons/minute then it would take 12 minutes to irrigate a 6’x6’ filter. Plant Replacement: In some cases, plants will require replacement. Please follow the procedures below to ensure a properly functioning Filterra® system. 1. Remove the existing plant, and leave as much of the Filterra® media in place as possible. 2. Select a replacement per the Filterra® Bioscape® Activation Package. 3. Prior to removing the plant from the container, ensure the soil moisture is sufficient to maintain the integrity of the root ball. If needed, pre-wet the container plant. 4. Cut away any roots which are growing out of the container drain holes. 5. Plant(s) should be carefully removed from the pot by gently pounding on the sides of the container with the fist to loosen root ball. Then carefully slide out. Do not lift plant(s) by trunk as this can break roots and cause soil to fall off. Extract the root ball in a horizontal position and support it to prevent it from breaking apart. Alternatively, the pot can be cut away to minimize root ball disturbance. 6. Excavate a hole with a diameter 4” greater than the root ball, gently place the plant(s). 7. Plant the tree/shrub/grass with the top of the root ball 1” above surrounding media to allow for settling. 8. All plants should have the main stem centered in the tree grate (where applicable) upon completion of installation. 9. Reinstall or add mulch to a depth of 3” per Contech’s mulch specifications for Filterra® systems. www.ContechES.com/filterra | 800-338-11228 1. Inspection of Filterra and surrounding area • Record individual unit before maintenance with photograph (numbered). Record on Maintenance Report (see example in this document) the following: 2. Removal of erosion control stones • Set aside erosion control stones for reuse after mulch has been replaced. • Dig out silt (if any) and mulch and remove trash & foreign items. 3. Removal of debris, trash and mulch • After removal of mulch and debris, measure distance from the top of the Filterra engineered media soil to the top of the top slab. Compare the measured distance to the distance shown on the approved Contract Drawings for the system. Add Filterra media (not top soil or other) to bring media up as needed to distance indicated on drawings. Record on Maintenance Report the following: Standing Water yes | no Is Bypass Clear yes | no If yes answered to any of these observations, record with close-up photograph (numbered). Record on Maintenance Report the following: Silt/Clay yes | no Bypass Clear yes | no Leaves yes | no # of Buckets Removed ________ Record on Maintenance Report the following: Is scour present around the inlet areas? yes | no If answering yes, consider adding additional erosion control stone. Maintenance Visit Procedure Keep sufficient documentation of maintenance actions to predict location specific maintenance frequencies and needs. An example Maintenance Report is included in this manual. www.ContechES.com/filterra | 800-338-1122 9 4. Removal and Disposal of Erosion Control Sock • Remove and dispose of erosion control sock if site conditions allow (site should be fully stabilized). Erosion control sock is no longer needed after 1-year post activation. 5. Mulch Replacement • Add mulch evenly across entire system to a depth of three inches. 6. Vegetation health evaluation and pruning • Examine the vegetation health and replace if necessary. Prune vegetation to encourage growth in the correct directions. Since Filterra® Bioscape® systems can contain many plants, only notation of individual damaged or unhealthy plants is necessary. »Record on Maintenance Report the following: »Vegetation Health »Vegetation Damage Document damaged or unhealthy plants with photographs. 7. Clean side slopes and area around the Filterra Bioscape system • Remove all trash and debris to be disposed of appropriately. 8. Complete paperwork • Complete Maintenance Report. Some jurisdictions require submission of maintenance reports in accordance with approvals. It is the responsibility of the owner to comply with local regulations. Maintenance Tools, Safety Equipment and Supplies Ideal tools include: camera, bucket, shovel, broom, pruners, hoe/rake, and tape measure. Appropriate Personal Protective Equipment (PPE) should be used in accordance with local or company procedures. This may include impervious gloves where the type of trash is unknown, high visibility clothing, barricades when working in close proximity to traffic and safety hats, glasses, and shoes. Most visits require minor trash removal and a full replacement of mulch. Mulch should be a double shredded, hardwood variety. www.ContechES.com/filterra | 800-338-112210 Maintenance Checklist Filterra Inspection & Maintenance Log Filterra System Size/Model: _____________________________Location: ____________________________________________ Drainage System Failure Problem Conditions to Check Condition that Should Exist Actions Inlet Excessive sediment or trash accumulation. Accumulated sediments or trash impair free flow of water into Filterra. Inlet should be free of obstructions allowing free distributed flow of water into Filterra. Sediments and/or trash should be removed. Mulch Cover Trash and floatable debris accumulation.Excessive trash and/or debris accumulation.Minimal trash or other debris on mulch cover. Trash and debris should be removed and mulch cover raked level. Ensure bark nugget mulch is not used. Mulch Cover “Ponding” of water on mulch cover. “Ponding” in unit could be indicative of clogging due to excessive fine sediment accumulation or spill of petroleum oils. Stormwater should drain freely and evenly through mulch cover. Recommend contact manufacturer and replace mulch as a minimum. Vegetation Plants not growing or in poor condition. Soil/mulch too wet, evidence of spill. Incorrect plant selection. Pest infestation. Vandalism to plants. Plants should be healthy and pest free.Contact manufacturer for advice. Vegetation Plant growth excessive. Plants should be appropriate to the species and location of Filterra. Trim/prune plants in accordance with typical landscaping and safety needs. Maintenance is ideally to be performed twice annually. Date Mulch & Debris Removed Depth of Mulch Added Mulch Brand Vegetation Species Issues with System Comments 1/1/17 5 – 5 gal Buckets 3”Lowe’s Premium Brown Mulch Galaxy Magnolia - Standing water in downstream structure - Removed blockage in downstream structure www.ContechES.com/filterra | 800-338-1122 11 Appendix 1 – Filterra® Bioscape® Activation Package Filterra Bioscape Activation Package | Page 1 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants are not provided by the contractor. ® FILTERRA® BIOSCAPE® ACTIVATION PACKAGE (No Precast Vaults Provided)ENGINEERED SOLUTIONS It is the purchaser’s responsibility to Activate the Filterra Bioscape System and provide adequate measures to prevent construction related runoff from entering the Filterra Bioscape system. Included with your purchase is Supervised Activation of the Filterra system by the manufacturer as well as a 1-year warranty from delivery of the system. The purchaser must ensure that the site is acceptable for Filterra Bioscape Activation. A checklist (included as page 2 of this document must be completed and submitted to the Contech Activation Coordinator. The minimum requirements for Filterra Bioscape Activation are as follows: 1. The purchaser must have sourced vegetation meeting the requirements outlined in “Plant Selection for Filterra Systems” below. 2. A pre-construction meeting is required to discuss site requirements, logistics planning and activation FAQ and red flags. 3. The site landscaping must be fully stabilized, i.e. full landscaping installed and some grass cover (not just straw and seed) is required to reduce sediment transport. Construction debris and materials should be removed from surrounding area. 4. Final paving must be completed. Final paving ensures that paving materials will not enter and contaminate the Filterra system during the paving process, and that the plant will receive runoff from the drainage area, assisting with plant survival for the Filterra system. 5. All immediate upstream and downstream structures should be placed with piping into the system already installed for connection during activation. Plant Selection for Filterra® Bioscape® Systems All Filterra systems require vegetation for proper long-term performance. As indicated in the Filterra Bioscape Activation Package, the Contractor is responsible for sourcing the proper vegetation prior to Supervised Activation. Contech or a Contech representative will supervise installation the vegetation during the Activation process. Contractors must ensure the vegetation meets the following 3 requirements: 1. Select plant(s) as specified in the engineering plans and specifications AND that are listed on Contech’s Configuration Specific Plant Lists. 2. All plants MUST be container-grown in nursery containers no larger than 15 gallons. Crated and/or Ball/Burlap plants are NOT permitted. 3. Quantities should be selected based on plant palette options found starting on page 3 of this document. If Contech or Contech’s representative shows up for Supervised Activation and any of the 3 requirements above are not met, Activation cannot be performed and the Contractor will be billed a $1,500 Unprepared Site fee*. www.ContechES.com/filterra | 800-338-112212 Filterra Bioscape Activation Package | Page 2 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants are not provided by the contractor. ® Filterra® Contractor Activation Checklist Requested Activation Date: _____________________System Designation: ______________________________________________ Project Name: _______________________________________________________________________________________________ Site Contact Name: _______________________________________Site Contact Phone/Email: ____________________________ Site Owner/End User Name: _________________________Site Owner/End User Phone/Email: ____________________________ NOTE: Please ensure that all of the above conditions have been met prior to activation request. A mobilization fee (minimum $1000.00) applies for each activation visit requested by Customer where Contech determines that the site does not meet the above conditions suitable for activation. Signature Date ENGINEERED SOLUTIONS Please complete the following checklist, sign, date, and submit with your activation request to your Contech Project Consultant. Along with the checklist, fill out the as-built dimensions of the Filterra Bioscape system excavation(s), and attach photos of the Filterra Bioscape excavation(s). This information is essential to ensure the proper amount of material is provided. Checklist: Upstream drainage area to Filterra Bioscape system is stabilized. Filterra Bioscape excavated per plan dimensions to bottom of Filterra underdrain stone depth. Surface area of media area must match order quantities. If additional depth of drain rock is required per site plans, additional drain rock is installed to the Filterra Bioscape underdrain pipe elevation. Excavation sides vertical from bottom of excavation to top of mulch (Approximately 34” when 6” underdrain is utilized). Excavation sides maximum slope 3:1 from top of mulch to finished grade. Side slopes above top of mulch elevation stabilized with sod or other slope stabilization. Bioscape Inlet (BSI) structure or other inlet/bypass structure installed and properly backfilled with maximum 3:1 slopes to top of mulch elevation. Inflow pipe(s) connected from BSI or other inlet structure to edge of Filterra Bioscape system excavation. Outflow pipe(s) connected from edge of Filterra Bioscape system excavation to downstream structure. Outflow pipe(s) are SDR35, properly sized per site plan underdrain pipe size(s). Excavation is dry and free from construction related sediment and debris. Bottom of excavation is properly scarified. Excavation is accessible by standard construction equipment. Plants have been purchased in accordance with the guidance in “Plant Selection for Filterra Bioscape Systems” Photos attached. A B C DF E A. OVERALL EXCAVATION WIDTH: _________FT B. OVERALL EXCAVATION LENGTH: _________FT C. OVERALL EXCAVATION HEIGHT: _________FT D. FILTERRA BED HEIGHT: _________FT E. FILTERRA MEDIA BED WIDTH: _________FT F. FILTERRA MEDIA BED LENGTH: _________FT As-Built Dimensions www.ContechES.com/filterra | 800-338-1122 13 Filterra Bioscape Activation Package | Page 3 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants are not provided by the contractor. ® Filterra® Bioscape Plant Palettes KEY: (refer to plant lists for species sizing) A. 5 B. 2 C. 1 25 SF example A. EXTRA SMALL GRASS • Up to 2’ mature spread • 1-2 gallon typical (1 gal. minimum) B. SMALL GRASS/SHRUB • 2’-4’ mature spread • 1-7 gallon typical C. MEDIUM SHRUB • 4’-6’ mature spread • 1-7 gallon typical D. LARGE SHRUB OR EXTRA LARGE SHRUB OR TREE • 6’ mature spread and greater, 30’ max. mature height • Up to 15 gallon maximum A. 9 B. 3 D. 1 C. 250 SF example A. 20 B. 6 C. 3 D. 2 100 SF example A. 15 B. 4 D. 1 C. 2 75 SF example NOTE: For larger vaults and in-ground Filterra Bioscape systems, palettes can be scaled (i.e. Qty 6 of the 175 SF Palette can be used for a 1056 SF Filterra Bioscape). MIX & MATCH SUBSTITUTION OPTIONS: 1 Large Shrub or Extra Large Shrub or Tree • 2 Medium Shrubs • 4 Small Grass/SHrubs • 12 Extra Small Grasses 1 Medium Shrub • 2 Small Grass/Shrubs • 6 Extra Small Grasses 1 Small Grass/Shrub • 3 Extra Small Grasses www.ContechES.com/filterra | 800-338-112214 Filterra Bioscape Activation Package | Page 4 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants are not provided by the contractor. ® A. 24 B. 8 C. 4 D. 2 125 SF example A. 32 B. 10 C. 5 D. 3 150 SF example C. 5 D. 3 A. 36 B. 10 175 SF example In some cases, Contech may consider alternate plant species as approved by the Product Manager. Please list the plant name in the space below and submit this sheet to your Contech Activation Coordinator. If the plant species is approved, either the Product Manager or the Activation Coordinator will sign the form and return to you for inclusion with your Activation Checklist. Requested Plant Species: ___________________________________________Approved: _______________________________ Date: ____________________________________ PDF 1/23 © 2023 Contech Engineered Solutions LLC, a QUIKRETE Company www.ContechES.com/filterra | 800-338-1122 15 NOTES ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ PDF 1/23 © 2023 Contech Engineered Solutions LLC, a QUIKRETE Company 9100 Centre Pointe Drive, Suite 400 West Chester, OH 45069 info@conteches.com | 800-338-1122 www.ContechES.com ALL RIGHTS RESERVED. PRINTED IN THE USA. NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY. APPLICATIONS SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS AND DECISIONS, AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION. CONTECH MAKES NO WARRANTY WHATSOEVER, EXPRESS OR IMPLIED, RELATED TO THE APPLICATIONS, MATERIALS, COATINGS, OR PRODUCTS DISCUSSED HEREIN. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH’S CONDITIONS OF SALE (AVAILABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION. ® Bioretention Systems ENGINEERED SOLUTIONS 1 SECTION (_____) Filterra®Bioscape Configuration Bioretention System Standard Specification 1.0 GENERAL 1.1 This item shall govern the furnishing and installation of the Filterra® Bioscape Bioretention System by Contech Engineered Solutions LLC, complete and operable as shown and as specified herein, in accordance with the requirements of the plans and contract documents. 1.2 Contractor shall furnish all labor, materials, equipment and incidentals necessary to install and/or prepare the site for placement of the bioretention system, appurtenances and incidentals in accordance with the Drawings and as specified herein. 1.3 Bioretention system shall utilize the physical, chemical and biological mechanisms of an engineered biofiltration media, plant and microbe complex to remove pollutants typically found in urban stormwater runoff. The treatment system shall be a fully equipped, pre- constructed, drop-in-place unit designed for applications in the urban landscape to treat contaminated runoff from impervious surfaces. 1.4 Bioretention plants shall be incorporated into the system with plant material extending into the treatment zone of the engineered media at time of Activation. 1.5 The bioretention system shall be of a type that has been installed and in use for a minimum of five (5) consecutive years preceding the date of installation of the system. The Manufacturer shall have been, during the same consecutive five (5) year period, engaged in the engineering design and production of systems deployed for the treatment of storm water runoff and which have a history of successful production, acceptable to the Engineer of Record and/or the approving Jurisdiction. The Manufacturer of the Filterra Bioscape Bioretention System shall be, without exception: Contech Engineered Solutions LLC 9100 Centre Pointe Drive West Chester, OH, 45069 Tel: 1 800 338 1122 1.6 Applicable provisions of any Division shall govern work in this section. 1.7 Manufacturer or authorized supplier to submit shop drawings for bioretention system with engineered biofiltration media and accessory equipment. Drawings shall include principal dimensions, engineered biofiltration media placement, and location of piping. 1.7.1 Manufacturer or authorized supplier shall submit site preparation and installation instructions to the contractor. 1.7.2 Manufacturer or authorized supplier shall submit Operations and Maintenance Manual to the contractor. 2 1.7.3 Before installation of the bioretention system, Contractor shall obtain the written approval of the Engineer of Record for the system drawings. 1.8 No product substitutions shall be accepted unless submitted 10 days prior to project bid date, or as directed by the Engineer of Record. Submissions for substitutions require review and approval by the Engineer of Record, for hydraulic performance, impact to project designs, equivalent treatment performance, and any required project plan and report (hydrology/hydraulic, water quality, stormwater pollution) modifications that would be required by the approving jurisdictions/agencies. Contractor to coordinate with the Engineer of Record any applicable modifications to the project estimates of cost, bonding amount determinations, plan check fees for changes to approved documents, and/or any other regulatory requirements resulting from the product substitution. 2.0 MATERIALS 2.1 All system components including engineered biofiltration media, underdrain stone, PVC underdrain piping, and mulch must be included as part of the bioretention system and shall be provided by Contech Engineered Solutions LLC. 2.1.1 Engineered biofiltration media shall consist of both organic and inorganic components. Stormwater shall be directed to flow vertically through the media profile, saturating the full media profile without downstream flow control. 2.1.2 Underdrain stone shall be of size and shape to provide adequate bridging between the media and stone for the prevention of migration of fine particles. Underdrain stone must also be able to convey the design flow rate of the system without restriction and be approved for use in the Filterra Bioscape Bioretention System by Contech Engineered Solutions LLC. 2.1.3 PVC Underdrain Piping shall be SDR35 with perforation pattern designed to convey system design flow rate without restriction. 2.1.4 Mulch shall be double shredded wood or bark mulch approved for use with the Filterra Bioscape Bioretention System by Contech Engineered Solutions LLC. 2.2 Vegetation shall be provided by the contractor and comply with the type and size required by the site plans and shall be alive and free of obvious signs of disease. 2.3 Filterra Bioscape containment basin or structure shall be provided by the contractor in accordance with the Engineer of Record site plans. 3.0 PERFORMANCE 3.1 Treatment Capabilities shall be verified via third-party report following either TAPE or TARP protocols. 3.1.1 Engineered biofiltration media minimum treatment flow rate shall be 140”/hr. The system shall be designed to ensure that high flow events shall bypass the engineered biofiltration media preventing erosion and resuspension of 3 pollutants. 3.1.2 The system shall remove a minimum of 85% Total Suspended Solids (TSS). 3.1.3 The system shall remove a minimum of 62% Total Phosphorus (TP). 3.1.4 The system shall remove a minimum of 34% Total Nitrogen (TN). 3.2 Quality Assurance and Quality Control procedures shall be followed for all batches of engineered biofiltration media produced. Engineered biofiltration media shall be certified by the Manufacturer for performance and composition. 3.2.1 Media particle size distribution and composition shall be verified as per relevant ASTM Standards. 3.2.2 Media pollutant removal performance shall be verified as per relevant ASTM Standards as well as a minimum of one scientific method approved by the USEPA. 3.2.3 Media hydraulic performance shall be verified as per relevant ASTM Standards. 3.2.4 Media fertility shall be verified as per a minimum of one published scientific method. 3.3 The Manufacturer shall ensure through third party full scale field testing of installed units that the design flow rate of the system is not reduced over time. Studies shall be performed on a minimum of 10 systems of various ages, maintenance frequencies, and land uses. At least 80% of the tested systems shall have been installed 2.5 or more years. At least 50% of the systems shall have previous maintenance intervals greater than 2 times the manufacturer’s recommendation. 4.0 EXECUTION 4.1 Contractor to prepare site for installation of the Filterra Bioscape Bioretention system as per the “Filterra Bioscape Activation Guide for Contractors” provided by the Manufacturer. 4.1.1 Excavation of basin or installation of Cast-in-Place vault for the placement of system components shall be completed by contractor 4.1.2 Inlet and outlet pipes shall be provided to the edge of the extents of the Engineered Media for connection of underdrain during system installation by contractor. 4.1.3 All bypass structures, piping, or other mechanisms should be installed and in place by contractor prior to Filterra Bioscape System Activation. 4.2 The bioretention system shall not be placed in operation (activated) until the project site is clean and stabilized (construction erosion control measures no longer required). The project site includes any surface that contributes storm drainage to the system. All impermeable 4 surfaces shall be clean and free of dirt and debris. All catch basins, manholes and pipes shall be free of dirt and sediment. 4.3 Activation consists of the placement of all system components identified in Section 2. Activation must be provided by the contractor under supervision by Contech Engineered Solutions, LLC, or a Contech certified 3rd Party Activation provider. 4.4 To ensure long term performance of the bioretention system, continuing annual maintenance programs should be performed or purchased by the owner per the latest Filterra Bioscape Bioretention System Operation and Maintenance manual. StormTech® Chamber Systems for Stormwater Management MC-3500 & MC-7200 Design Manual 1 1.0 Product Information ....................................................................2 2.0 Foundation for Chambers................................................................8 3.0 Required Materials/Row Separation......................................................11 4.0 Hydraulics.............................................................................13 5.0 Cumulative Storage Volume.............................................................15 6.0 System Sizing..........................................................................20 7.0 Structural Cross Sections and Specifications ..............................................22 8.0 General Notes .........................................................................24 9.0 Inspection and Maintenance ............................................................25 *For SC-160LP, SC-310, SC-740 & DC-780 designs, please refer to the SC-160LP/SC-310/SC-740/DC-780 Design Manual. StormTech Engineering Services assists design professionals in specifying StormTech stormwater systems. This assistance includes the layout of chambers to meet the engineer’s volume requirements and the connections to and from the chambers. They can also assist converting and cost engineering projects currently specified with ponds, pipe, concrete vaults and other manufactured stormwater detention/ retention products. Please note that it is the responsibility of the site design engineer to ensure that the chamber bed layout meets all design requirements and is in compliance with applicable laws and regulations governing a project. This manual is exclusively intended to assist engineers in the design of subsurface stormwater systems using StormTech chambers. Table of Contents SHEETOFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATERESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 430262 505/12/21S123456JEKJEKMC-3500 CHAMBEREXAMPLE PROJECTDATEDRWNCHKDDESCRIPTION0015'30'StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®NOTES·MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECHNICAL NOTE 6.32 FOR MANIFOLD SIZINGGUIDANCE.·DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BENECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLD COMPONENTS IN THE FIELD.·THE SITE DESIGN ENGINEER MUST REVIEW ELEVATIONS AND IF NECESSARY ADJUST GRADING TO ENSURE THE CHAMBERCOVER REQUIREMENTS ARE MET.·THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARINGCAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR DETERMINING THE SUITABILITY OF THE SOIL ANDPROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASEDONCE THIS INFORMATION IS PROVIDED. 24" ADS N-12 BOTTOM CONNECTIONINVERT 2.06" ABOVE CHAMBER BASE(SEE NOTES) 18" X 18" ADS N-12 TOP MANIFOLDINVERT 20.03" ABOVE CHAMBER BASE(SEE NOTES) 6" ADS N-12 DUAL WALL PERFORATED HDPE UNDERDRAIN(SIZE TBD BY ENGINEER / SOLID OUTSIDE PERIMETER STONE) INSPECTION PORT PROPOSED STRUCTURE W/ELEVATED BYPASS MANIFOLDMAXIMUM INLET FLOW 16.2 CFS(DESIGN BY ENGINEER / PROVIDED BY OTHERS) PROPOSED OUTLET CONTROL STRUCTUREMAXIMUM OUTLET FLOW 11.0 CFS(DESIGN BY ENGINEER / PROVIDED BY OTHERS) ISOLATOR ROW PLUS(SEE DETAIL ) PLACE MINIMUM 17.5' OF ADSPLUS175 WOVEN GEOTEXTILE OVERBEDDING STONE AND UNDERNEATH CHAMBER FEET FOR SCOURPROTECTION AT ALL CHAMBER INLET ROWS 18" PARTIAL CUT END CAP, PART# MC3500IEPP18TC ORMC3500IEPP18TWTYP OF ALL MC-3500 18" TOP CONNECTIONS 18" PARTIAL CUT END CAP, PART# MC3500IEPP18BC OR MC3500IEPP18BWTYP OF ALL MC-3500 18" BOTTOM CONNECTIONS 24" PARTIAL CUT END CAP, PART# MC3500IEPP24BC OR MC3500IEPP24BWTYP OF ALL MC-3500 24" BOTTOM CONNECTIONS AND ISOLATOR PLUS ROWS PROPOSED LAYOUT60STORMTECH MC-3500 CHAMBERS12STORMTECH MC-3500 END CAPS12STONE ABOVE (in)9 STONE BELOW (in)40 % STONE VOID12,149 INSTALLED SYSTEM VOLUME (CF) (PERIMETER STONE INCLUDED)3,674 SYSTEM AREA (ft²)280 SYSTEM PERIMETER (ft) PROPOSED ELEVATIONS979.50 MAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED)973.50 MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC)973.00 MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC)973.00 MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT)973.00 MINIMUM ALLOWABLE GRADE (TOP OF RIGID PAVEMENT)972.50 TOP OF STONE971.50 TOP OF MC-3500 CHAMBER969.42 18" TOP MANIFOLD INVERT967.92 24" BOTTOM CONNECTION INVERT967.92 24" ISOLATOR ROW PLUS CONNECTION INVERT967.90 18" BOTTOM MANIFOLD INVERT967.75 BOTTOM OF MC-3500 CHAMBER967.00 UNDERDRAIN INVERT967.00 BOTTOM OF STONE 18" X 18" ADS N-12 BOTTOM MANIFOLDINVERT 1.77" ABOVE CHAMBER BASE(SEE NOTES)22.25'20.25'96.15'89.77'43.60'41.00'71.86'61.10' 2 StormTech MC-3500 Chamber Designed to meet the most stringent industry performance standards for superior structural integrity while providing designers with a cost-effective method to save valuable land and protect water resources. The StormTech system is designed primarily to be used under parking lots, thus maximizing land usage for private (commercial) and public applications. StormTech chambers can also be used in conjunction with Green Infrastructure, thus enhancing the performance and extending the service life of these practices. MC-3500 Chamber (not to scale) Nominal Specifications Size (LxWxH)90” x 77” x 45” (2286 x 1956 x 1143 mm) Chamber Storage 109.9 ft3 (3.11 m3) Min. Installed Storage*175.0 ft3 (4.96 m3) Weight 134 lbs (60.8 kg) *Assumes a minimum of 12” (300 mm) of stone above, 9” (230 mm) of stone below chambers, 6” (150 mm) of stone between chambers/end caps and 40% stone porosity. MC-3500 Chamber (not to scale) Nominal Specifications Size (LxWxH)26.5” x 71” x 45.1” (673 x 1803 x 1145 mm) End Cap Storage 14.9 ft3 (0.42 m3) Min. Installed Storage*45.1 ft3 (1.28 m3) Weight 49 lbs (22.2 kg) *Assumes a minimum of 12” (300 mm) of stone above, 9” (230 mm) of stone below, 6” (150 mm) of stone perimeter, 6” (150 mm) of stone between chambers/end caps and 40% stone porosity. Shipping 15 chambers/pallet 7 end caps/pallet 7 pallets/truck 3 Storage Volume Per Chamber/End Cap ft3 (m3) Bare Unit Storage ft3 (m3) Chamber/End Cap and Stone Volume — Stone Foundation Depth in. (mm) 9 (230)12 (300)15 (375)18 (450) Chamber 109.9 (3.11)175.0 (4.96)179.9 (5.09)184.9 (5.24)189.9 (5.38) End Cap 14.9 (0.42)45.1 (1.28)46.6 (1.32)48.3 (1.37)49.9 (1.41) Note: Assumes 6” (150 mm) row spacing, 40% stone porosity, 12” (300 mm) stone above and includes the bare chamber/end cap volume. Volume of Excavation Per Chamber/End Cap yd3 (m3) Stone Foundation Depth 9” (230 mm)12” (300 mm)15” (375 mm)18” (450 mm) Chamber 11.9 (9.1)12.4 (9.5)12.8 (9.8)13.3 (10.2) End Cap 4.0 (3.1)4.1 (3.2)4.3 (3.3)4.4 (3.4) Note: Assumes 6” (150 mm) of separation between chamber rows and 24” (600 mm) of cover. The volume of excavation will vary as depth of cover increases. Amount of Stone Per Chamber ENGLISH tons (yd3) Stone Foundation Depth 9”12”15”18” Chamber 8.5 (6.0)9.1 (6.5)9.7 (6.9)10.4 (7.4) End Cap 3.9 (2.8)4.1 (2.9)4.3 (3.1)4.5 (3.2) METRIC kg (m3)230 mm 300 mm 375 mm 450 mm Chamber 7711 (4.6)8255 (5.0)8800 (5.3)9435 (5.7) End Cap 3538 (2.1)3719 (2.2)3901 (2.4)4082 (2.5) Note: Assumes 12” (300 mm) of stone above and 6” (150 mm) row spacing and 6” (150 mm) of perimeter stone in front of end caps. Special applications will be considered on a project by project basis. Please contact our application department should you have a unique application for our team to evaluate. 4 StormTech MC-7200 Chamber Designed to meet the most stringent industry performance standards for superior structural integrity while providing designers with a cost-effective method to save valuable land and protect water resources. The StormTech system is designed primarily to be used under parking lots, thus maximizing land usage for private (commercial) and public applications. StormTech chambers can also be used in conjunction with Green Infrastructure, thus enhancing the performance and extending the service life of these practices. MC-7200 Chamber (not to scale) Nominal Specifications Size (LxWxH)83.4” x 100” x 60” (2120 x 2540 x 1524 mm) Chamber Storage 175.9 ft3 (4.98 m3) Min. Installed Storage*267.3 ft3 (7.56 m3) Weight 205 lbs (92.9 kg) *Assumes a minimum of 12” (300 mm) of stone above, 9” (230 mm) of stone below chambers, 9” (230 mm) of stone between chambers/end caps and 40% stone porosity. MC-7200 Chamber (not to scale) Nominal Specifications Size (LxWxH)38” x 90” x 61” (965 x 2286 x 1549 mm) End Cap Storage 39.5 ft3 (1.12 m3) Min. Installed Storage*115.3 ft3 (3.26 m3) Weight 90.0 lbs (40.8 kg) *Assumes a minimum of 12” (300 mm) of stone above, 9” (230 mm) of stone below, 12” (300 mm) of stone perimeter, 9” (230 mm) of stone between chambers/end caps and 40% stone porosity. Shipping 7 chambers/pallet 5 end caps/pallet 6 pallets/truck 5 Storage Volume Per Chamber/End Cap ft3 (m3) Bare Unit Storage ft3 (m3) Chamber/End Cap and Stone Volume — Stone Foundation Depth in. (mm) 9 (230)12 (300)15 (375)18 (450) Chamber 175.9 (4.98)267.3 (7.57)273.3 (7.74)279.3 (7.91)285.2 (8.08) End Cap 39.5 (1.12)115.3 (3.26)111.9 (3.17)121.9 (3.45)125.2 (3.54) Note: Assumes 9” (230 mm) row spacing, 40% stone porosity, 12” (300 mm) stone above and includes the bare chamber/end cap volume. End cap volume assumes 12” (300 mm) stone perimeter in front of end cap. Volume of Excavation Per Chamber/End Cap yd3 (m3) Stone Foundation Depth 9” (230 mm)12” (300 mm)15” (375 mm)18” (450 mm) Chamber 17.2 (13.2)17.7 (13.5)18.3 (14.0)18.8 (14.4) End Cap 9.7 (7.4)10.0 (7.6)10.3 (7.9)10.6 (8.1) Note: Assumes 9” (230 mm) of separation between chamber rows, 12” (300 mm) of perimeter in front of the end caps, and 24” (600 mm) of cover. The volume of excavation will vary as depth of cover increases. Amount of Stone Per Chamber ENGLISH tons (yd3) Stone Foundation Depth 9”12”15”18” Chamber 11.9 (8.5)12.6 (9.0)13.4 (9.6)14.6 (10.1) End Cap 9.8 (7.0)10.2 (7.3)10.6 (7.6)11.1 (7.9) METRIC kg (m3)230 mm 300 mm 375 mm 450 mm Chamber 10796 (6.5)11431 (6.9)12156 (7.3)13245 (7.7) End Cap 8890 (5.3)9253 (5.5)9616 (5.8)10069 (6.0) Note: Assumes 12” (300 mm) of stone above and 9” (230 mm) row spacing and 12” (300 mm) of perimeter stone in front of end caps. Special applications will be considered on a project by project basis. Please contact our application department should you have a unique application for our team to evaluate. 6 1.0 Product Information 1.1 Product Design StormTech’s commitment to thorough product testing programs, materials evaluation and adherence to national standards has resulted in two more superior products. Like other StormTech chambers, the MC- 3500 and MC-7200 are designed to meet the full scope of design requirements of the American Society of Testing Materials (ASTM) International specification F2787 “Standard Practice for Structural Design of Thermoplastic Corrugated Wall Stormwater Collection Chambers” and produced to the requirements of the ASTM F 2418 “Standard Specification for Polypropylene (PP) Corrugated Stormwater Collection Chambers”. The StormTech MC-3500 and MC-7200 chambers provide the full AASHTO safety factors for live loads and permanent earth loads. The ASTM F 2787 standard provides specific guidance on how to design thermoplastic chambers in accordance with AASHTO Section 12.12. of the AASHTO LRFD Bridge Design Specifications. ASTM F 2787 requires that the safety factors included in the AASHTO guidance are achieved as a prerequisite to meeting ASTM F 2418. The three standards provide both the assurance of product quality and safe structural design. The design of larger chambers in the same tradition of our other chambers required the collaboration of experts in soil-structure interaction, plastics and manufacturing. Years of extensive research, including laboratory testing and field verification, were required to produce chambers that are ready to meet both the rigors of installation and the longevity expected by engineers and owners. This Design Manual provides the details and specifications necessary for consulting engineers to design stormwater management systems using the MC-3500 and MC-7200 chambers. It provides specifications for storage capacities, layout dimensions as well as requirements for design to ensure a long service life. The basic design concepts for foundation and backfill materials, subgrade bearing capacities and row spacing remain equally as pertinent for the MC-3500 and MC-7200 as the SC-740, SC-310 and DC-780 chamber systems. However, since many design values and dimensional requirements are different for these larger chambers than the SC-740, SC-310 and DC-780 chambers, design manuals and installation instructions are not interchangeable. This manual includes only those details, dimensions, cover limits, etc for the MC-3500 and MC-7200 and is intended to be a stand-alone design guide for the MC- 3500 and MC-7200 chambers. A Construction Guide specifically for these two chamber models has also been published. 1.2 Technical Support The StormTech Technical Services Department is available to assist the engineer with the layout of MC-3500 and MC-7200 chamber systems and answer questions regarding all the StormTech chamber models. Call the Technical Services Department, email us at info@stormtech.com or contact your local StormTech representative. 1.3 MC-3500 and MC-7200 Chambers All StormTech chambers are designed to the full scope of AASHTO requirements without repeating end walls or other structural reinforcing. StormTech’s continuously curved, elliptical arch and the surrounding angular backfill are the key components of the structural system. With the addition of patent pending integral stiffening ribs (Figure 5), the MC-3500 and MC-7200 are assured to provide a long, safe service life. Like other StormTech chambers, the MC-3500 and MC-7200 are produced from high quality, impact modified resins which are tested for short-term and long-term mechanical properties. With all StormTech chambers, one chamber type is used for the start, middle and end of rows. Rows are formed by overlapping the upper joint corrugation of the next chamber over the lower joint corrugation of the previous chamber (Figure 6). 1.4 Chamber Joints All StormTech chambers are designed with an optimized joining system. The height and width of the end corrugations have been designed to provide the required structural safety factors while providing an unobstructed flow path down each row. 7 1.0 Product Information To assist the contractor, StormTech chambers are molded with simple assembly instructions and arrows that indicate the direction in which to build rows. The corrugation valley immediately adjacent to the lower joint corrugation is marked “Overlap Here - Lower Joint.” The corrugation valley immediately adjacent to the upper joint corrugation is marked “Build This Direction - Upper Joint.” Two people can safely and efficiently carry and place chambers without cumbersome connectors, special tools or heavy equipment. Each row of chambers must begin and end with a joint corrugation. Since joint corrugations are of a different size than the corrugations along the body of the chamber, chambers cannot be field cut and installed. Only whole MC-3500 and MC-7200 chambers can be used. For system layout assistance contact StormTech. 1.5 MC-3500 and MC-7200 End Caps The MC-3500 and MC-7200 end caps are easy to install. These end caps are designed with a corrugation joint that fits over the top of either end of the chamber. The end cap joint is simply set over the top of either of the upper or lower chamber joint corrugations (Figure 7). The MC-3500 end cap has pipe cutting guides for 12”–24” (300 mm–600 mm) top inverts (Figure 9). The MC-7200 end cap has pipe cutting guides for 12”–42” (300 mm–1050 mm) bottom inverts and 12”–24” (300 mm–600 mm) top inverts (Figure 8). Standard and custom pre-cored end caps are available. MC-3500 pre-cored end caps, 18” in diameter and larger include a welded crown plate. Figure 5 - Chamber and End Cap Components Figure 6 - Chamber Joint Overlap Figure 7 - End Cap Joint Overlap 8 1.0 Product Information Figure 8 - MC-7200 End Cap Inverts Figure 9 - MC-3500 End Cap Inverts 2.1 Foundation Requirements StormTech chamber systems can be installed in various soil types. The subgrade bearing capacity and the cover height over the chambers determine the required depth of clean, crushed, angular foundation stone below the chambers. Foundation stone, also called bedding, is the stone between the subgrade soils and the feet of the chamber. Flexible structures are designed to transfer a significant portion of both live and dead loads through the surrounding soils. Chamber systems accomplish this by creating load paths through the columns of embedment stone between and around the rows of chambers. This creates load concentrations at the base of the columns between the rows. The foundation stone spreads out the concentrated loads to distributed loads that can be supported by the subgrade soils. Since increasing the cover height (top of chamber to finished grade) causes increasing soil load, a greater depth of foundation stone is necessary to distribute the load to the subgrade soils. Table 1 and 2 specify the minimum required foundation depths for varying cover heights and allowable subgrade bearing capacities. These tables are based on StormTech service loads. The minimum required foundation depth is 9” (230 mm) for both chambers. 2.0 Foundations for Chambers For additional guidance on foundation stone design please see our Technical Note 6.22 - StormTech Subgrade Performance 2.2 Weaker Soils StormTech has not provided guidance for subgrade bearing capacities less than 2000 pounds per square foot [(2.0 ksf) (96 kPa)]. These soils are often highly vari- able, may contain organic materials and could be more sensitive to moisture. A geotechnical engineer must be consulted if soils with bearing capacities less than 2000 psf (96 kPa) are present. 9 2.0 Foundations for Chambers Cover Hgt. ft.(m) Minimum Bearing Resistance for Service Loads ksf (kPa) 4.4(211)4.3(206)4.2(201)4.1(196)4.0(192)3.9(187)3.8(182)3.7(177)3.6(172)3.5(168)3.4(163)3.3(158)3.2(153)3.1(148)3.0(144)2.9(139)2.8(134)2.7(129)2.6(124)2.5(120)2.4(115)2.3(110)2.2(105)2.1(101)2.0(96) 1.5(0.46)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450) 2.0(0.61)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450) 2.5(0.76)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)21 (525) 3.0(0.91)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525) 3.5(1.07)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)24 (600) 4.0(1.22)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600) 4.5(1.37)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)27 (675) 5.0(1.52)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)24 (600)24 (600)24 (600)27 (675)30 (750) 5.5(1.68)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)24 (600)24 (600)24 (600)27 (675)27 (675)30 (750) 6.0(1.83)9(230)9(230)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)27 (675)27 (675)30 (750)30 (750) 6.5(1.98)9(230)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)27 (675)27 (675)30 (750)30 (750)30 (750) 7.0(2.13)12(300)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)27 (675)27 (675)30 (750)30 (750)30 (750)30 (750) 7.5(2.30)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)27 (675)27 (675)27 (675)30 (750)30 (750)30 (750)30 (750) 8.0(2.44)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)24 (600)27 (675)27 (675)30 (750)30 (750)30 (750)30 (750)30 (750) NOTE: The design engineer is solely responsible for assessing the bearing resistance (allowable bearing capacity) of the subgrade soils and determining the depth of foundation stone. Subgrade bearing resistance should be assessed with consideration for the range of soil moisture conditions expected under a stormwater system. Table 1 - MC-3500 Minimum Required Foundation Depth in inches (millimeters) Assumes 6” (150 mm) row spacing. Figure 10A - MC-3500 Structural Cross Section Detail (Not to Scale) 45"(1140 mm) 18"(450 mm) MIN* 8'(2.4 m)MAX 12" (300 mm) TYP77" (1950 mm) 12" (300 mm) MIN 6"(150 mm) MIN DEPTH OF STONE TO BE DETERMINEDBY SITE DESIGN ENGINEER 9" (230 mm) MIN6" (150 mm) MIN MC-3500END CAP PERIMETER STONE EXCAVATION WALL(CAN BE SLOPEDOR VERTICAL) PAVEMENT LAYER (DESIGNEDBY SITE DESIGN ENGINEER) CHAMBERS SHALL BE BE DESIGNED IN ACCORDANCE WITH ASTM F2787"STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTICCORRUGATED WALL STORMWATER COLLECTION CHAMBERS". GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35%FINES, COMPACT IN 12" (300 mm) MAX LIFTS TO 95% PROCTORDENSITY. SEE THE TABLE OF ACCEPTABLE FILL MATERIALS. ADS GEOSYTHETICS 601T NON-WOVENGEOTEXTILE ALL AROUND CLEAN, CRUSHED,ANGULAR EMBEDMENT STONE CHAMBERS SHALL MEET ASTM F2418 "STANDARDSPECIFICATION FOR POLYPROPLENE (PP) CORRUGATEDWALL STORMWATER COLLECTION CHAMBERS". EMBEDMENT STONE SHALL BE A CLEAN, CRUSHED AND ANGULARSTONE WITH AN AASHTO M43 DESIGNATION BETWEEN #3 AND #4 SITE DESIGN ENGINEER IS RESPONSIBLE FOR ENSURINGTHE REQUIRED BEARING CAPACITY OF SOILS *MINIMUM COVER TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR, INCREASE COVER TO 24" (600 mm). Special applications will be considered on a project by project basis. Please contact our applications department should you have a unique application for our team to evaluate. 10 2.0 Foundations for Chambers Cover Hgt. ft.(m) Minimum Bearing Resistance for Service Loads ksf (kPa) 4.4(211)4.3(206)4.2(201)4.1(196)4.0(192)3.9(187)3.8(182)3.7(177)3.6(172)3.5(168)3.4(163)3.3(158)3.2(153)3.1(148)3.0(144)2.9(139)2.8(134)2.7(129)2.6(124)2.5(120)2.4(115)2.3(110)2.2(105)2.1(101)2.0(96) 2.0(0.61)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)21 (525)21 (525) 2.5(0.76)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)24 (600) 3.0(0.91)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)21 (525)21 (525)24 (600)24 (600)27 (675) 3.5(1.07)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)24 (600)24 (600)27 (675)30 (750) 4.0(1.22)9(230)9(230)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)27 (675)27 (675)30 (750)30 (750) 4.5(1.37)9(230)9(230)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)24 (600)24 (600)27 (675)27 (675)30 (750)33 (825)33 (825) 5.0(1.52)9(230)9(230)9(230)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)27 (675)27 (675)30 (750)33 (825)33 (825)36 (900) 5.5(1.68)9(230)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)18(450)18(450)21 (525)21 (525)24 (600)24 (600)24 (600)27 (675)27 (675)30 (750)33 (825)33 (825)36 (900)36 (900) 6.0(1.83)12(300)12(300)12(300)12(300)12(300)15 (375)15 (375)15 (375)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)27 (675)27 (675)30 (750)30 (750)33 (825)33 (825)36 (900)36 (900)36 (900) 6.5(1.98)12(300)12(300)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)18(450)21 (525)21 (525)24 (600)24 (600)24 (600)27 (675)27 (675)30 (750)30 (750)33 (825)33 (825)36 (900)36 (900)36 (900)36 (900) 7.0(2.13)15 (375)15 (375)15 (375)15 (375)18(450)18(450)18(450)18(450)21 (525)21 (525)21 (525)24 (600)24 (600)24 (600)27 (675)27 (675)30 (750)30 (750)33 (825)36 (900)36 (900)36 (900)36 (900)36 (900)36 (900) NOTE: The design engineer is solely responsible for assessing the bearing resistance (allowable bearing capacity) of the subgrade soils and determining the depth of foundation stone. Subgrade bearing resistance should be assessed with consideration for the range of soil moisture conditions expected under a stormwater system. Table 2 - MC-7200 Minimum Required Foundation Depth in inches (millimeters) Assumes 9” (230 mm) row spacing. Figure 10B - MC-7200 Structural Cross Section Detail (Not to Scale) 24"(600 mm) MIN* 7.0'(2.1 m)MAX 12" (300 mm) TYP100" (2540 mm) ADS GEOSYNTHETICS 601T NON-WOVENGEOTEXTILE ALL AROUND CLEAN, CRUSHED,ANGULAR EMBEDMENT STONE 12" (300 mm) MIN 12" (300 mm) MIN 9"(230 mm) MIN DEPTH OF STONE TO BE DETERMINEDBY SITE DESIGN ENGINEER 9" (230 mm) MIN PERIMETER STONE EXCAVATION WALL(CAN BE SLOPED OR VERTICAL) MC-7200END CAP SITE DESIGN ENGINEER IS RESPONSIBLE FOR ENSURINGTHE REQUIRED BEARING CAPACITY OF SOILS PAVEMENT LAYER (DESIGNEDBY SITE DESIGN ENGINEER) 60"(1524 mm) CHAMBERS SHALL MEET ASTM F2419 "STANDARDSPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATEDWALL STORMWATER COLLECTION CHAMBERS". EMBEDMENT STONE SHALL BE A CLEAN, CRUSHED AND ANGULARSTONE WITH AN AASHTO M43 DESIGNATION BETWEEN #3 AND #4 CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH ASTM F2787"STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTICCORRUGATED STORMWATER COLLECTION CHAMBERS". *MINIMUM COVER TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR, INCREASE COVER TO 30" (750 mm). GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35% FINES,COMPACT IN 12" (300 mm) MAX LIFTS TO 95% PROCTOR DENSITY. SEETHE TABLE OF ACCEPTABLE FILL MATERIALS. Special applications will be considered on a project by project basis. Please contact our applications department should you have a unique application for our team to evaluate. 11 3.0 Required Materials/Row Separation 3.1 Foundation and Embedment Stone The stone surrounding the chambers consists of the foundation stone below the chambers and embedment stone surrounding the chambers. The foundation stone and embedment stone are important components of the structural system and also provide open void space for stormwater storage. Table 3 provides the stone specifications that achieve both structural requirements and a porosity of 40% for stormwater storage. Figure 11 specifies the extents of each backfill stone location. Once layer ‘C’ is placed, any soil/material can be placed in layer ‘D’ up to the finished grade. Most pavement subbase soils can be used to replace the materials of layer ‘C’ or ‘D’ at the design engineer’s discretion. Table 3 - Acceptable Fill Materials Please Note:1. The listed AASHTO designations are for gradations only. The stone must also be clean, crushed, angular. For example, a specification for #4 stone would state: “clean, crushed, angular NO. 4 (AASHTO m43) stone”.2. Stormtech compaction requirements are met for ‘A’ location materials when placed and compacted in 9” (230 mm) (max) lifts using two full coverages with a vibratory compactor.3. Where infiltration surfaces may be compromised by compaction, for standard design load conditions, a flat surface may be achieved by raking or dragging without compaction equipment. For special load designs, contact stormtech for compaction requirements. Figure 11 - Fill Material Locations SHEET OFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATERESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 43026ADVANCED DRAINAGE SYSTEMS, INC.R2 #MM/DD/YYS######XXXXXXCITY - STATEPROJECT NAMEDATEDRWNCHKDDESCRIPTION001'2'ACCEPTABLE FILL MATERIALS: STORMTECH MC-7200 CHAMBER SYSTEMS PLEASE NOTE:1.THE LISTED AASHTO DESIGNATIONS ARE FOR GRADATIONS ONLY. THE STONE MUST ALSO BE CLEAN, CRUSHED, ANGULAR. FOR EXAMPLE, A SPECIFICATION FOR #4 STONE WOULD STATE: "CLEAN, CRUSHED, ANGULAR NO. 4 (AASHTO M43) STONE".2.STORMTECH COMPACTION REQUIREMENTS ARE MET FOR 'A' LOCATION MATERIALS WHEN PLACED AND COMPACTED IN 9" (230 mm) (MAX) LIFTS USING TWO FULL COVERAGES WITH A VIBRATORY COMPACTOR.3.WHERE INFILTRATION SURFACES MAY BE COMPROMISED BY COMPACTION, FOR STANDARD DESIGN LOAD CONDITIONS, A FLAT SURFACE MAY BE ACHIEVED BY RAKING OR DRAGGING WITHOUT COMPACTION EQUIPMENT. FOR SPECIAL LOAD DESIGNS, CONTACT STORMTECH FORCOMPACTION REQUIREMENTS.4.ONCE LAYER 'C' IS PLACED, ANY SOIL/MATERIAL CAN BE PLACED IN LAYER 'D' UP TO THE FINISHED GRADE. MOST PAVEMENT SUBBASE SOILS CAN BE USED TO REPLACE THE MATERIAL REQUIREMENTS OF LAYER 'C' OR 'D' AT THE SITE DESIGN ENGINEER'S DISCRETION. NOTES: 1.CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418-16a, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED WALL STORMWATER COLLECTION CHAMBERS" CHAMBER CLASSIFICATION 60x101 2.MC-7200 CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH ASTM F2787 "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". 3.THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR ASSESSING THE BEARING RESISTANCE (ALLOWABLE BEARING CAPACITY) OF THE SUBGRADE SOILS AND THE DEPTH OF FOUNDATION STONE WITH CONSIDERATION FOR THE RANGE OF EXPECTED SOIL MOISTURE CONDITIONS. 4.PERIMETER STONE MUST BE EXTENDED HORIZONTALLY TO THE EXCAVATION WALL FOR BOTH VERTICAL AND SLOPED EXCAVATION WALLS. 5.REQUIREMENTS FOR HANDLING AND INSTALLATION: ·TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING STACKING LUGS. ·TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS THAN 3”. ·TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT AS DEFINED IN SECTION 6.2.8 OF ASTM F2418 SHALL BE GREATER THAN OR EQUAL TO 500 LBS/IN/IN. AND b) TO RESIST CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73° F / 23° C), CHAMBERS SHALL BE PRODUCED FROM REFLECTIVE GOLD OR YELLOW COLORS. MATERIAL LOCATION DESCRIPTION AASHTO MATERIALCLASSIFICATIONS COMPACTION / DENSITY REQUIREMENT D FINAL FILL: FILL MATERIAL FOR LAYER 'D' STARTS FROM THETOP OF THE 'C' LAYER TO THE BOTTOM OF FLEXIBLEPAVEMENT OR UNPAVED FINISHED GRADE ABOVE. NOTE THATPAVEMENT SUBBASE MAY BE PART OF THE 'D' LAYER ANY SOIL/ROCK MATERIALS, NATIVE SOILS, OR PER ENGINEER'S PLANS.CHECK PLANS FOR PAVEMENT SUBGRADE REQUIREMENTS.N/A PREPARE PER SITE DESIGN ENGINEER'S PLANS. PAVEDINSTALLATIONS MAY HAVE STRINGENT MATERIAL ANDPREPARATION REQUIREMENTS. C INITIAL FILL: FILL MATERIAL FOR LAYER 'C' STARTS FROM THETOP OF THE EMBEDMENT STONE ('B' LAYER) TO 24" (600 mm)ABOVE THE TOP OF THE CHAMBER. NOTE THAT PAVEMENTSUBBASE MAY BE A PART OF THE 'C' LAYER. GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35% FINES ORPROCESSED AGGREGATE. MOST PAVEMENT SUBBASE MATERIALS CAN BE USED IN LIEU OF THISLAYER. AASHTO M145¹A-1, A-2-4, A-3 OR AASHTO M43¹3, 357, 4, 467, 5, 56, 57, 6, 67, 68, 7, 78, 8, 89, 9, 10 BEGIN COMPACTIONS AFTER 24" (600 mm) OF MATERIAL OVERTHE CHAMBERS IS REACHED. COMPACT ADDITIONAL LAYERS IN12" (300 mm) MAX LIFTS TO A MIN. 95% PROCTOR DENSITY FORWELL GRADED MATERIAL AND 95% RELATIVE DENSITY FORPROCESSED AGGREGATE MATERIALS. B EMBEDMENT STONE: FILL SURROUNDING THE CHAMBERSFROM THE FOUNDATION STONE ('A' LAYER) TO THE 'C' LAYERABOVE.CLEAN, CRUSHED, ANGULAR STONE AASHTO M43¹3, 4 A FOUNDATION STONE: FILL BELOW CHAMBERS FROM THESUBGRADE UP TO THE FOOT (BOTTOM) OF THE CHAMBER.CLEAN, CRUSHED, ANGULAR STONE AASHTO M43¹3, 4 PLATE COMPACT OR ROLL TO ACHIEVE A FLAT SURFACE.2,3 NO COMPACTION REQUIRED. 24"(600 mm) MIN* MC-7200 - 7.0' (2.1 m) MAXMC-3500 - 8.0' (2.4m) MAX 12" (300 mm) MINMC-7200 - 100" (2540 mm)MC-3500 - 77" (1946 mm) ADS GEOSYNTHETICS 601T NON-WOVENGEOTEXTILE ALL AROUND CLEAN, CRUSHED,ANGULAR STONE IN A & B LAYERS 12" (300 mm) MIN 12" (300 mm) MIN MC-7200 - 9" (230 mm) MINMC-3500 - 6" (150 mm) MIN D C B A *TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVEDINSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR,INCREASE COVER TO 30" (750 mm). DEPTH OF STONE TO BE DETERMINEDBY SITE DESIGN ENGINEER 9" (230 mm) MIN PERIMETER STONE(SEE NOTE 4) EXCAVATION WALL(CAN BE SLOPED OR VERTICAL) END CAP SUBGRADE SOILS PAVEMENT LAYER (DESIGNEDBY SITE DESIGN ENGINEER) MC-7200 - 60" (1524 mm)MC-3500 - 45" (1143 mm) Material Location Description AASHTO Material Classifications Compaction / Density Requirement D Final Fill: Fill Material for layer ‘D’ starts from the top of the ‘C’ layer to the bottom of flexible pavement or unpaved finished grade above. Note that pavement subbase may be part of the ‘D’ layer. Any soil/rock materials, native soils, or per engineer’s plans. check plans for pavement subgrade requirements. N/A Prepare per site design engineer’s plans. Paved installations may have stringent material and preparation requirements. C Initial Fill: Fill material for layer ‘C’ starts from the top of the embedment stone (‘B’ layer) to 24” (600 mm) above the top of the chamber. note that pavement subbase may be a part of the ‘C’ layer. Granular well-graded soil/aggregate mixtures, <35% fines or processed aggregate.most pavement subbase materials can be used in lieu of this layer. AASHTO M1451 a-1,a-2-4,a-3orAASHTO M431 3, 357, 4, 467, 5, 56, 57, 6, 67, 68, 7, 78, 8, 89, 9, 10 Begin compactoins after 24” (600 mm) of material over the chambers is reached. compact addtional layers in 12” (300 mm) max lifts to a min. 95% proctor density for well-graded material and 95% relative density for processed aggregate materials. B Embedment Stone: Fill surrounding the chambers form the foudation stone (‘A’ layer) to the ‘C’ layer above. Clean, crushed, angular stone AASHTO M431 3, 4 No compaction required A Foundation Stone: Fill below chambers from the subgrade up to the foot (bottom) of the chamber. Clean, crushed, angular stone AASHTO M431 3, 4 Plate compact or roll to achieve a flat surface. 2 3 12 3.0 Required Materials/Row Separation 3.2 Fill Above Chambers Refer to Table 3 and Figure 11 for acceptable fill material above the clean, crushed, angular stone. StormTech requires a minimum of 24” (600 mm) from the top of the chamber to the bottom of flexible pavement. For non-paved installations where rutting from vehicles may occur StormTech requires a minimum of 30” (750 mm) from top of chamber to finished grade. 3.3 Geotextile Separation A non-woven geotextile meeting AASHTO M288 Class 2 separation requirements must be installed to completely envelope the system and prevent soil intrusion into the crushed, angular stone. Overlap adjacent geotextile rolls per AASHTO M288 separation guidelines. Contact StormTech for a list of acceptable geotextiles. 3.4 Parallel Row Separation/Perpendicular Bed Separation Parallel Row Separation The minimum installed spacing between parallel rows after backfilling is 9” (230 mm) for the MC- 7200 chambers and 6” (150mm) for the MC-3500 (measurement taken between the outside edges of the feet). Spacers may be used for layout convenience. Row spacing wider than the minimum spacing above may be specified. Perpendicular Bed Separation When beds are laid perpendicular to each other, a minimum installed spacing of 36” (900 mm) between beds is required. 3.5 Special Structural Designs StormTech engineers may provide special structural designs to enable deeper cover depths or increase the capacity to carry higher live loads. Special designs may utilize the additional strength that can be achieved by compaction of embedment stone or by increasing the spacing between rows. Increasing the spacing between chamber rows may also facilitate the application of StormTech chambers with either less foundation stone or with weaker subgrade soils. This may be a good option where vertical restrictions on site prevent the use of a deeper foundation. Contact ADS Engineering Services for more information on special structural designs. System Cross Section Minimum Row Spacing 13 4.0 Hydraulics 4.1 General StormTech subsurface chamber systems offer the flexibility for a variety of inlet and outlet configurations. Contact the StormTech Technical Services Department or your local StormTech representative for assistance configuring inlet and outlet connections. The open graded stone around and under the chambers provides a significant conveyance capacity ranging from approximately 0.8 cfs (23 l/s) to 13 cfs (368 l/s) per MC-3500 chamber and for the MC-7200 chamber. The actual conveyance capacity is dependent upon stone size, depth of foundation stone and head of water. Although the high conveyance capacity of the open graded stone is an important component of the flow network, StormTech recommends that a system of inlet and outlet manifolds be designed to distribute and convey the peak flow through the chamber system. It is the responsibility of the design engineer to provide the design flow rates and storage volumes for the stormwater system and to ensure that the final design meets all conveyance and storage requirements. However, StormTech will work with the design engineer to assist with manifold and chamber layouts that meet the design objectives. 4.2 The Isolator® Row Plus The Isolator Row Plus is a system that inexpensively captures total suspended solids (TSS) and debris and provides easy access for inspection and maintenance. In a typical configuration, a single layer of ADS Plus fabric is placed between the chambers and the stone foundations. This fabric traps and filters sediments as well as protects the stone base during cleaning and maintenance. Each installed MC-3500 chamber and MC-3500 end cap provides 42.9 ft2 (4.0 m2) and 7.5 ft2 (0.7 m2) of bottom filter area respectively. Each installed MC-7200 chamber and MC-7200 end cap provides 57.9 ft2 (5.4 m2) and 12.8 ft2 (1.19 m2) of bottom filter area respectively. The Isolator Row Plus can be configured for maintenance objectives or, in some regulatory jurisdictions, for water quality objectives. For water quality applications, the Isolator Row Plus can be sized based on water quality volume or flow rate. All Isolator Plus Rows require: 1) a manhole for maintenance access, 2) a means of diversion of flows to the Isolator Row Plus 3) a high flow bypass and 4)FLAMP (Flared End Ramp). When used on an Isolator Row Plus, a 24” FLAMP (flared end ramp) is attached to the inside of the inlet pipe with a provided threaded rod and bolt. The FLAMP then lays on top of the ADS Plus fabric.. Flow diversion can be accomplished by either a weir in the upstream access manhole or simply by feeding the Isolator Row Plus at a lower elevation than the high flow bypass. Contact StormTech for assistance sizing Isolator Plus Rows. When additional stormwater treatment is required, StormTech systems can be configured using a treatment train approach where other stormwater BMPs are located in series. Figure 12 - StormTech Isolator Row Plus Detail 14 STORMTECHISOLATOR ROW PLUS STRUCTURE WITH OVERFLOW WEIR(48" (1200 mm) MIN. DIA. WITH 24" (600 mm)SUMP RECOMMENDED FOR ACCESS) OPTIONAL PRE-TREATMENT 24" (600 mm) DIA. ACCESSPIPE REQUIRED OVERFLOW MANIFOLD STRUCTURE WITH OVERFLOW WEIR(48" (1200 mm) MIN. DIA. WITH 24" (600 mm)SUMP RECOMMENDED FOR ACCESS) STORMTECHCHAMBERS 4.0 Hydraulics Table 4 - Allowable Inlet Flows* Table 5 - Maximum Outlet Flow Rate Capacities From StormTech Oulet Manifolds Table 6 - Standard Distances From Base of Chamber to Invert of Inlet and Outlet Manifolds on StormTech End Caps Inlet Pipe Diameter Inches (mm)Allowable Maximum Flow Rate cfs (l/s) 12 (300)2.48 (70) 15 (375)3.5 (99) 18 (450)5.5 (156) 24 (600)8.5 (241) [MC-3500] 24 (600)9.5 (269) [MC-7200] Pipe Diameter Flow (CFS)Flow (L/S) 6” (150 mm)0.4 11.3 8” (200 mm)0.7 19.8 10” (250 mm)1.0 28.3 12” (300 mm)2.0 56.6 15” (375 mm)2.7 76.5 18” (450 mm)4.0 113.3 24” (600 mm)7.0 198.2 30” (750 mm)11.0 311.5 36” (900 mm)16.0 453.1 42” (1050 mm)22.0 623.0 48” (1200 mm)28.0 792.9 MC-3500 ENDCAPS Pipe Diameter Inv. (in)Inv. (mm)Top6” (150 mm)33.21 841 8” (200 mm)31.16 789 10” (250 mm)29.04 738 12” (300 mm)26.36 671 15” (375 mm)23.39 594 18” (450 mm)20.03 509 24” (600 mm)14.48 369 Bottom12” (750 mm)1.35 34 15” (900 mm)1.5 40 18” (1050 mm)1.77 46 24” (1200 mm)2.06 52 MC-7200 ENDCAPS Pipe Diameter Inv. (in)Inv. (mm)Top12” (300 mm)35.69 907 15” (375 mm)32.72 831 18” (450 mm)29.36 746 24” (600 mm)23.05 585 Bottom12” (750 mm)1.55 34 15” (900 mm)1.7 43 18” (1050 mm)1.97 50 24” (1200 mm)2.26 57 Figure 13 - Typical Inlet Configuration With Isolator Row Plus and Scour Protection 4.3 Inlet Manifolds The primary function of the inlet manifold is to convey and distribute flows to a sufficient number of rows in the chamber bed such that there is ample conveyance capacity to pass the peak flows without creating an unacceptable backwater condition in upstream piping or scour the foundation stone under the chambers. Manifolds are connected to the end caps either at the top or bottom of the end cap. Standard distances from the base of chamber to the invert of inlet and outlet manifolds connecting to StormTech end caps can be found in table 6. High inlet flow rates from either connection location produce a shear scour potential of the foundation stone. Inlet flows from top inlets also produce impingement scour potential. Scour potential is reduced when standing water is present over the foundation stone. However, for safe design across the wide range of applications, StormTech assumes minimal standing water at the time the design flow occurs. To minimize scour potential, StormTech recommends the installation of woven scour protection fabric at each inlet row. This enables a protected transition zone from the concentrated flow coming out of the inlet pipe to a uniform flow across the entire width of the chamber for both top and bottom connections. Allowable flow rates for design are dependent upon: the elevation of inlet pipe, foundation stone size and scour protection. With an appropriate scour protection geotextile installed from the end cap to at least 14.5 ft (4.42 m) in front of the inlet pipe for the MC-3500 and for the MC-7200, for both top and bottom feeds, the flow rates listed in Table 4 can be used for all StormTech specified foundation stone gradations. *See StormTech’s Tech Note 6.32 for manifold sizing guidance. *Assumes appropriate length of scour fabric per section 4.3 15 5.0 Cumulative Storage Volumes 4.4 Outlet Manifolds The primary function of the outlet manifold is to convey peak flows from the chamber system to the outlet control structure. Outlet manifolds are often sized for attenuated flows. They may be smaller in diameter and have fewer row connections than inlet manifolds. In some applications however, the intent of the outlet piping is to convey an unattenuated bypass flow rate and manifolds may be sized similar to inlet manifolds. Since chambers are generally flowing at or near full at the time of the peak outlet flow rate, scour is generally not governing and outlet manifold sizing is based on pipe flow equations. In most cases, StormTech recommends that outlet manifolds connect the same rows that are connected to an inlet manifold. This provides a continuous flow path through open conduits to pass the peak flow without dependence on passing peak flows through stone. The primary function of the underdrains is to draw down water stored in the stone below the invert of the manifold. Underdrains are generally not sized for conveyance of the peak flow. The maximum outlet flow rate capacities from StormTech outlet manifolds can be found in Table 5. 4.5 Inserta Tee® Inlet Connections Figure 15 - Inserta Tee Detail Figure 14 - Typical Inlet, Outlet and Underdrain Configuration BED PERIMETER STORMTECHCHAMBERS OUTLETMANIFOLD INLETMANIFOLD SCOURPROTECTION NUMBER AND SIZEOF UNDERDRAIN(S)PER ENGINEER’SDESIGN OUTLET CONTROL STRUCTURE(PER ENGINEER’S DESIGN/PROVIDED BY OTHERS) CONVEYANCE PIPE MATERIAL MAY VARY (PVC, HDPE, ETC.) INSERTA TEE CONNECTION PLACE ADS PLUS WOVEN GEOTEXTILE (CENTERED ON INSERTA-TEE INLET) OVER BEDDING STONE FOR SCOUR PROTECTION AT SIDE INLET CONNECTIONS, GEOTEXTILE MUST EXTEND 6” (150 mm) PAST CHAMBER FOOT MC-7200 Depth of Water in System Inches (mm) Cumulative Chamber Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 66 (1676)0.00 175.02 (4.956) 65 (1651)0.00 173.36 (4.909) 64 (1626)0.00 171.71 (4.862) 63 (1600)0.00 170.06 (4.816) 62 (1575)0.00 168.41 (4.7.69) 61 (1549)0.00 166.76 (4.722) 60 (1524)0.00 165.10 (4.675) 59 (1499)0.00 163.45 (4.628) 58 (1473)0.00 161.80 (4.582) 57 (1448)0.00 160.15 (4.535) 56 (1422)0.00 158.49 (4.488) 55 (1397)0.00 156.84 (4.441) 54 (1372)109.95 (3.113)155.19 (4.394) 53 (1346)109.89 (3.112)153.50 (4.347) 52 (1321)109.69 (3.106)151.73 (4.297) 51 (1295)109.40 (3.098)149.91 (4.245) 50 (1270)109.00 (3.086)148.01 (4.191) 49 (1245)108.31 (3.067)145.95 (4.133) 48 (1219)107.28 (3.038)143.68 (4.068) 47 (1194)106.03 (3.003)141.28 (4.000) 46 (1168)104.61 (2.962)138.77 (3.930) 45 (1143)103.04 (2.918)136.17 (3.856) 44 (1118)101.33 (2.869)133.50 (3.780) 43 (1092)99.50 (2.818)130.75 (3.702) 42 (1067)97.56 (2.763)127.93 (3.623) 41 (1041)95.52 (2.705)125.06 (3.541) 40 (1016)93.39 (2.644)122.12 (3.458) 39 (991)91.16 (2.581)119.14 (3.374) 38 (965)88.86 (2.516)116.10 (3.288) 37 (948)86.47 (2.449)113.02 (3.200) 36 (914)84.01 (2.379)109.89 (3.112) 35 (889)81.49 (2.307)106.72 (3.022) 34 (864)78.89 (2.234)103.51 (2.931) 33 (838)76.24 (2.159)100.27 (2.839) 16 5.0 Cumulative Storage Volumes Table 7 – MC-3500 Incremental Storage Volume Per ChamberAssumes 40% stone porosity. Calculations are based upon a 9” (230 mm) stone base under the chambers, 12” (300 mm) of stone above chambers, and 6” (150 mm) of spacing between chambers. Depth of Water in System Inches (mm) Cumulative Chamber Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 32 (813)73.52 (2.082)96.98 (2.746) 31 (787)70.75 (2.003)93.67 (2.652) 30 (762)67.92 (1.923)90.32 (2.558) 29 (737)65.05 (1.842)86.94 (2.462) 28 (711)62.12 (1.759)83.54 (2.366) 27 (686)59.15 (1.675)80.10 (2.268) 26 (680)56.14 (1.590)76.64 (2.170) 25 (635)53.09 (1.503)73.16 (2.072) 24 (610)49.99 (1.416)69.65 (1.972) 23 (584)46.86 (1.327)66.12 (1.872) 22 (559)43.70 (1.237)62.57 (1.772) 21 (533)40.50 (1.147)59.00 (1.671) 20 (508)37.27 (1.055)55.41 (1.569) 19 (483)34.01 (0.963)51.80 (1.467) 18 (457)30.72 (0.870)48.17 (1.364) 17 (432)27.40 (0.776)44.53 (1.261) 16 (406)24.05 (0.681)40.87 (1.157) 15 (381)20.69 (0.586)37.20 (1.053) 14 (356)17.29 (0.490)33.51 (0.949) 13 (330)13.88 (0.393)29.81 (0.844) 12 (305)10.44 (0.296)26.09 (0.739) 11 (279)6.98 (0.198)22.37 (0.633) 10 (254)3.51 (0.099)18.63 (0.527) 9 (229)0.00 14.87 (0.421) 8 (203)0.00 13.22 (0.374) 7 (178)0.00 11.57 (0.328) 6 (152)0.00 9.91 (0.281) 5 (127)0.00 8.26 (0.234) 4 (102)0.00 6.61 (0.187) 3 (76)0.00 4.96 (0.140) 2 (51)0.00 3.30 (0.094) 1 (25)0.00 1.65 (0.047) NOTE: Add 1.65 ft3 (0.047 m3) of storage for each additional inch (25 mm) of stone foundation. Contact StormTech for cumulative volume spreadsheets in digital format. StoneCover StoneCover Tables 7 and 8 provide cumulative storage volumes for the MC-3500 chamber and end cap. These tables can be used to calculate the stage-storage relationship for the retention or detention system. Digital spreadsheets in which the number of chambers and end caps can be input for quick cumulative storage calculations are available at www.stormtech.com. For assistance with site-specific calculations or input into routing software, contact the StormTech Technical Services Department. 17 5.0 Cumulative Storage Volume Table 8 – MC-3500 Incremental Storage Volume Per End CapAssumes 40% stone porosity. Calculations are based upon a 9” (230 mm) stone base under the chambers, 12” (300 mm) of stone above end caps, and 6” (150 mm) of spacing between end caps and 6” (150 mm) of stone perimeter. Depth of Water in System Inches (mm) Cumulative End Cap Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 66 (1676)0.00 45.10 (1.277) 65 (1651)0.00 44.55 (1.262) 64 (1626)0.00 44.00 (1.246) 63 (1600)0.00 43.46 (1.231) 62 (1575)0.00 42.91 (1.2.15) 61 (1549)0.00 42.36 (1.200) 60 (1524)0.00 41.81 (1.184) 59 (1499)0.00 41.27 (1.169) 58 (1473)0.00 40.72 (1.153) 57 (1448)0.00 40.17 (1.138) 56 (1422)0.00 39.62 (1.122) 55 (1397)0.00 39.08 (1.107) 54 (1372)15.64 (0.443)38.53 (1.091) 53 (1346)15.64 (0.443)37.98 (1.076) 52 (1321)15.63 (0.443)37.42 (1.060) 51 (1295)15.62 (0.442)36.85 (1.043) 50 (1270)15.60 (0.442)36.27 (1.027) 49 (1245)15.56 (0.441)35.68 (1.010) 48 (1219)15.51 (0.439)35.08 (0.993) 47 (1194)15.44 (0.437)34.47 (0.976) 46 (1168)15.35 (0.435)33.85 (0.959) 45 (1143)15.25 (0.432)33.22 (0.941) 44 (1118)15.13 (0.428)32.57 (0.922) 43 (1092)14.99 (0.424)31.91 (0.904) 42 (1067)14.83 (0.420)31.25 (0.885) 41 (1041)14.65 (0.415)30.57 (0.866) 40 (1016)14.45 (0.409)29.88 (0.846) 39 (991)14.24 (0.403)29.18 (0.826) 38 (965)14.00 (0.396)28.48 (0.806) 37 (948)13.74 (0.389)27.76 (0.786) 36 (914)13.47 (0.381)27.04 (0.766) 35 (889)13.18 (0.373)26.30 (0.745) 34 (864)12.86 (0.364)25.56 (0.724) Depth of Water in System Inches (mm) Cumulative Chamber Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 33 (838)12.53 (0.355)24.82 (0.703) 32 (813)12.18 (0.345)24.06 (0.681) 31 (787)11.81 (0.335)23.30 (0.660) 30 (762)11.42 (0.323)22.53 (0.638) 29 (737)11.01 (0.312)21.75 (0.616) 28 (711)10.58 (0.300)20.96 (0.594) 27 (686)10.13 (0.287)20.17 (0.571) 26 (680)9.67 (0.274)19.37 (0.549) 25 (635)9.19 (0.260)18.57 (0.526) 24 (610)8.70 (0.246)17.76 (0.503) 23 (584)8.19 (0.232)16.94 (0.480) 22 (559)7.67 (0.217)16.12 (0.456) 21 (533)7.13 (0.202)15.29 (0.433) 20 (508)6.59 (0.187)14.45 (0.409) 19 (483)6.03 (0.171)13.61 (0.385) 18 (457)5.46 (0.155)12.76 (0.361) 17 (432)4.88 (0.138)11.91 (0.337) 16 (406)4.30 (0.122)11.06 (0.313) 15 (381)3.70 (0.105)10.20 (0.289) 14 (356)3.10 (0.088)9.33 (0.264) 13 (330)2.49 (0.071)8.46 (0.240) 12 (305)1.88 (0.053)7.59 (0.215) 11 (279)1.26 (0.036)6.71 (0.190) 10 (254)0.63 (0.018)5.83 (0.165) 9 (229)0.00 4.93 (0.139) 8 (203)0.00 4.38 (0.124) 7 (178)0.00 3.83 (0.108) 6 (152)0.00 3.28 (0.093) 5 (127)0.00 2.74 (0.077) 4 (102)0.00 2.19 (0.062) 3 (76)0.00 1.64 (0.046) 2 (51)0.00 1.09 (0.031) 1 (25)0.00 0.55 (0.015) NOTE: Add 0.56 ft3 (0.016 m3) of storage for each additional inch (25 mm) of stone foundation. Contact StormTech for cumulative volume spreadsheets in digital format. StoneCover StoneCover 18 5.0 Cumulative Storage Volumes Table 9 – MC-7200 Incremental Storage Volume Per ChamberAssumes 40% stone porosity. Calculations are based upon a 9” (230 mm) stone base under the chambers, 12” (300 mm) of stone above chambers, and 9” (230 mm) of spacing between chambers. Depth of Water in System Inches (mm) Cumulative Chamber Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 81 (2057)0.00 267.30 (7.569) 80 (2032)0.00 265.30 (7.512) 79 (2007)0.00 263.30 (7.456) 78 (1981)0.00 261.31 (7.399) 77 (1956)0.00 259.31 (7.343) 76 (1930)0.00 257.31 (7.286) 75 (1905)0.00 255.32 (7.230) 74 (1880)0.00 253.32 (7.173) 73 (1854)0.00 251.32 (7.117) 72 (1829)0.00 249.33 (7.060) 71 (1803)0.00 247.33 (7.004) 70 (1778)0.00 245.33 (6.947) 69 (1753)175.90 (4.981)243.33 (6.890) 68 (1727)175.84 (4.979)241.30 (6.833) 67 (1702)175.65 (4.974)239.19 (6.773) 66 (1676)175.38 (4.966)237.03 (6.712) 65 (1651)175.02 (4.956)234.82 (6.649) 64 (1626)174.56 (4.943)232.54 (6.585) 63 (1600)173.82 (4.922)230.10 (6.516) 62 (1575)172.72 (4.891)227.45 (6.441) 61 (1549)171.41 (4.854)224.66 (6.362) 60 (1524)169.91 (4.811)221.76 (6.280) 59 (1499)168.25 (4.764)218.77 (6.195) 58 (1473)166.46 (4.714)215.70 (6.108) 57 (1448)164.53 (4.659)212.55 (6.019) 56 (1422)162.50 (4.602)209.33 (5.928) 55 (1397)160.36 (4.541)206.05 (5.835) 54 (1372)158.11 (4.477)202.70 (5.740) 53 (1346)155.77 (4.411)199.30 (5.644) 52 (1321)153.33 (4.342)195.84 (5.546) 51 (1295)150.81 (4.271)192.33 (5.446) 50 (1270)148.21 (4.197)188.78 (5.346) 49 (1245)145.53 (4.121)185.17 (5.244) 48 (1219)142.78 (4.043)181.52 (5.140) 47 (1194)139.96 (3.963)177.83 (5.036) 46 (1168)137.07 (3.881)174.10 (4.930) 45 (1143)134.11 (3.798)170.33 (4.823) 44 (1118)131.09 (3.712)166.52 (4.715) 43 (1092)128.01 (3.625)162.68 (4.607) 42 (1067)124.88 (3.536)158.80 (4.497) 41 (1041)121.68 (3.446)154.89 (4.386) Depth of Water in System Inches (mm) Cumulative Chamber Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 40 (1016)118.44 (3.354)150.94 (4.274) 39 (991)115.14 (3.260)146.97 (4.162) 38 (965)111.80 (3.166)142.96 (4.048) 37 (948)108.40 (3.070)138.93 (3.934) 36 (914)104.97 (2.972)134.87 (3.819) 35 (889)101.48 (2.874)130.78 (3.703) 34 (864)97.96 (2.774)126.67 (3.587) 33 (838)94.39 (2.673)122.54 (3.470) 32 (813)90.79 (2.571)118.38 (3.352) 31 (787)87.14 (2.468)114.19 (3.234) 30 (762)83.46 (2.363)109.99 (3.114) 29 (737)79.75 (2.258)105.76 (2.995) 28 (711)76.00 (2.152)101.52 (2.875) 27 (686)72.22 (2.045)97.25 (2.754) 26 (680)68.41 (1.937)92.97 (2.632) 25 (610)64.56 (1.828)88.66 (2.511) 24 (609)60.69 (1.719)84.34 (2.388) 23 (584)56.80 (1.608)80.01 (2.266) 22 (559)52.87 (1.497)75.66 (2.142) 21 (533)48.92 (1.385)71.29 (2.019) 20 (508)44.95 (1.273)66.91 (1.895) 19 (483)40.96 (1.160)62.52 (1.770) 18 (457)36.94 (1.046)58.11 (1.646) 17 (432)32.91 (0.932)53.69 (1.520) 16 (406)28.85 (0.817)49.26 (1.395) 15 (381)24.78 (0.702)44.82 (1.269) 14 (356)20.69 (0.586)40.37 (1.143) 13 (330)16.58 (0.469)35.91 (1.017) 12 (305)12.46 (0.353)31.44 (0.890) 11 (279)8.32 (0.236)26.96 (0.763) 10 (254)4.17 (0.118)22.47 (0.636) 9 (229)0.00 17.97 (0.509) 8 (203)0.00 15.98 (0.452) 7 (178)0.00 13.98 (0.396) 6 (152)0.00 11.98 (0.339) 5 (127)0.00 9.99 (0.283) 4 (102)0.00 7.99 (0.226) 3 (76)0.00 5.99 (0.170) 2 (51)0.00 3.99 (0.113) 1 (25)0.00 2.00 (0.057) NOTE: Add 2.00 ft3 (0.057 m3) of storage for each additional inch (25 mm) of stone foundation. Contact StormTech for cumulative volume spreadsheets in digital format. Tables 9 and 10 provide cumulative storage volumes for the MC-7200 chamber and end cap. These tables can be used to calculate the stage-storage relationship for the retention or detention system. Digital spreadsheets in which the number of chambers and end caps can be input for quick cumulative storage calculations are available at www.stormtech.com. For assistance with site-specific calculations or input into routing software, contact the StormTech Technical Services Department. StoneCover StoneCover 19 5.0 Cumulative Storage Volumes Table 10 – MC-7200 Incremental Storage Volume Per End Cap Assumes 40% stone porosity. Calculations are based upon a 9” (230 mm) stone base under the chambers, 12” (300 mm) of stone above end caps, and 9” (230 mm) of spacing between end caps and 6” (150 mm) of stone perimeter. Depth of Water in System Inches (mm) Cumulative End Cap Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 81 (2057)0.00 115.28 (3.264) 80 (2032)0.00 114.15 (3.232) 79 (2007)0.00 113.02 (3.200) 78 (1981)0.00 111.89 (3.168) 77 (1956)0.00 110.76 (3.136) 76 (1930)0.00 109.63 (3.104) 75 (1905)0.00 108.50 (3.072) 74 (1880)0.00 107.37 (3.040) 73 (1854)0.00 106.24 (3.008) 72 (1829)0.00 105.11 (2.976) 71 (1803)0.00 103.98 (2.944) 70 (1778)0.00 102.85 (2.912) 69 (1753)39.54 (1.120)101.72 (2.880) 68 (1727)39.53 (1.119)100.58 (2.848) 67 (1702)39.50 (1.118)99.43 (2.816) 66 (1676)39.45 (1.117)98.27 (2.783) 65 (1651)39.38 (1.115)97.10 (2.750) 64 (1626)39.30 (1.113)95.92 (2.716) 63 (1600)39.19 (1.110)94.73 (2.682) 62 (1575)39.06 (1.106)93.52 (2.648) 61 (1549)38.90 (1.101)92.29 (2.613) 60 (1524)38.71 (1.096)91.04 (2.578) 59 (1499)38.49 (1.090)89.78 (2.542) 58 (1473)38.24 (1.083)88.50 (2.506) 57 (1448)37.97 (1.075)87.21 (2.469) 56 (1422)37.67 (1.067)85.90 (2.432) 55 (1397)37.34 (1.057)84.57 (2.395) 54 (1372)36.98 (1.047)83.23 (2.357) 53 (1346)36.60 (1.036)81.87 (2.318) 52 (1321)36.19 (1.025)80.49 (2.279) 51 (1295)35.75 (1.012)79.10 (2.240) 50 (1270)35.28 (0.999)77.69 (2.200) 49 (1245)34.79 (0.985)76.26 (2.159) 48 (1219)34.27 (0.970)74.82 (2.119) 47 (1194)33.72 (0.955)73.36 (2.077) 46 (1168)33.15 (0.939)71.89 (2.036) 45 (1143)32.57 (0.922)70.40 (1.994) 44 (1118)31.96 (0.905)68.91 (1.951) 43 (1092)31.32 (0.887)67.40 (1.909) 42 (1067)30.68 (0.869)65.88 (1.866) 41 (1041)30.00 (0.850)64.35 (1.822) Depth of Water in System Inches (mm) Cumulative End Cap Storage ft3 (m3) Total System Cumulative Storage ft3 (m3) 40 (1016)29.30 (0.830)62.80 (1.778) 39 (991)28.58 (0.809)61.23 (1.734) 38 (965)27.84 (0.788)59.65 (1.689) 37 (948)27.07 (0.767)58.07 (1.644) 36 (914)26.29 (0.744)56.46 (1.599) 35 (889)25.48 (0.722)54.85 (1.553) 34 (864)24.66 (0.698)53.23 (1.507) 33 (838)23.83 (0.675)51.60 (1.461) 32 (813)22.98 (0.651)49.96 (1.415) 31 (787)22.12 (0.626)48.31 (1.368) 30 (762)21.23 (0.601)46.65 (1.321) 29 (737)20.32 (0.575)44.97 (1.273) 28 (711)19.40 (0.549)43.29 (1.226) 27 (686)18.48 (0.523)41.61 (1.178) 26 (680)17.54 (0.497)39.91 (1.130) 25 (610)16.59 (0.470)38.21 (1.082) 24 (609)15.62 (0.442)36.50 (1.033) 23 (584)14.64 (0.414)34.78 (0.985) 22 (559)13.66 (0.387)33.07 (0.936) 21 (533)12.66 (0.359)31.33 (0.887) 20 (508)11.65 (0.330)29.60 (0.838) 19 (483)10.63 (0.301)27.85 (0.3789) 18 (457)9.60 (0.272)26.11 (0.739) 17 (432)8.56 (0.242)24.35 (0.690) 16 (406)7.51 (0.213)22.59 (0.640) 15 (381)6.46 (0.183)20.83 (0.590) 14 (356)5.41 (0.153)19.07 (0.540) 13 (330)4.35 (0.123)17.31 (0.490) 12 (305)3.28 (0.093)15.53 (0.440) 11 (279)2.19 (0.062)13.75 (0.389) 10 (254)1.11 (0.031)11.97 (0.339) 9 (229)0.00 10.17 (0.288) 8 (203)0.00 9.04 (0.256) 7 (178)0.00 7.91 (0.224) 6 (152)0.00 6.78 (0.192) 5 (127)0.00 5.65 (0.160) 4 (102)0.00 4.52 (0.128) 3 (76)0.00 3.39 (0.096) 2 (51)0.00 2.26 (0.064) 1 (25)0.00 1.13 (0.032) NOTE: Add 1.08 ft3 (0.031 m3) of storage for each additional inch (25 mm) of stone foundation. Contact StormTech for cumulative volume spreadsheets in digital format. StoneCover StoneCover 20 6.0 MC-3500 Chamber System Sizing The following steps provide the calculations necessary for preliminary sizing of an MC-3500 chamber system. For custom bed configurations to fit specific sites, contact the StormTech Technical Services Department or your local StormTech representative. 1) Determine the amount of storage volume (VS) required. It is the design engineer’s sole responsibility to determine the storage volume required. 6) Determine the required bed size (S). The size of the bed will depend on the number of chambers and end caps required: MC-3500 area per chamber = 49.6 ft2 (4.6 m2) MC-3500 area per end cap = 16.4 ft2 (1.5 m2) S = (C x area per chamber) + (EC x area per end cap) NOTE: It is necessary to add 12” (300 mm) of stone perimeter parallel to the chamber rows and 6” (150 mm) of stone perimeter from the base of all end caps. The additional area due to perimeter stone is not included in the area numbers above. 7) Determine the amount of stone (Vst) required. To calculate the total amount of clean, crushed, angular stone required, multiply the number of chambers (C) and the number of end caps (EC) by the selected weight of stone from Table 12. NOTE: Clean, crushed, angular stone is also required around the perimeter of the system. Table 11 - Storage Volume Per Chamber/End Cap ft3 (m3) Bare Unit Storage ft3 (m3) Chamber/End Cap and Stone Volume — Stone Foundation Depth in. (mm) 9 (230)12 (300)15 (375)18 (450) MC-3500 Chamber 109.9 (3.11)175.0 (4.96)179.9 (5.09)184.9 (5.24)189.9 (5.38) MC-3500 End Cap 14.9 (0.42)45.1 (1.28)46.6 (1.32)48.3 (1.37)49.9 (1.41) NOTE: Assumes 6” (150 mm) row spacing, 40% stone porosity, 12” (300 mm) stone above and includes the bare chamber/end cap volume. End cap volume assumes 6” (150 mm) stone perimeter. Table 12 - Amount of Stone Per Chamber/End Cap ENGLISH tons (yd3) Stone Foundation Depth 9”12”15”18” Chamber 8.5 (6.0)9.1 (6.5)9.7 (6.9)10.4 (7.4) End Cap 3.9 (2.8)4.1 (2.9)4.3 (3.1)4.5 (3.2) METRIC kg (m3)230 mm 300 mm 375 mm 450 mm Chamber 7711 (4.6)8255 (5.0)8800 (5.3)9435 (5.7) End Cap 3538 (2.1)3719 (2.2)3901 (2.4)4082 (2.5) NOTE: Assumes 12” (300 mm) of stone above, and 6” (150 mm) row spacing, and 6” (150 mm) of perimeter stone in front of end caps. Table 13—Volume of Excavation Per Chamber/End Cap yd3 (m3) Stone Foundation Depth 9” (230 mm)12” (300 mm)15” (375 mm)18” (450 mm) Chamber 11.9 (9.1)12.4 (9.5)12.8 (9.8)13.3 (10.2) End Cap 4.0 (3.1)4.1 (3.2)4.3 (3.3)4.4 (3.4) NOTE: Assumes 6” (150 mm) separation between chamber rows, 6” (150 mm) of perimeter in front of end caps, and 24” (600 mm) of cover. The volume of excavation will vary as the depth of cover increases. 9) Determine the area of geotextile (F) required. The bottom, top and sides of the bed must be covered with a non-woven geotextile (filter fabric) that meets AASHTO M288 Class 2 requirements. The area of the sidewalls must be calculated and a 24” (600 mm) overlap must be included for all seams. Geotextiles typically come in 15 foot (4.57 m) wide rolls. 2) Determine the number of chambers (C) required. To calculate the number of chambers required for adequate storage, divide the storage volume (Vs) by the storage volume of the chamber (from Table 11), as follows: C = Vs / Storage Volume per Chamber 3) Determine the number of end caps required. The number of end caps (EC) required depends on the number of rows required by the project. Once the num- ber of chamber rows is determined, multiply the number of chamber rows by 2 to determine the number of end caps required. EC = No. of Chamber Rows x 2 NOTE: Additional end caps may be required for systems having inlet locations within the chamber bed. 4) Determine additional storage provided by end caps. End Caps will provide additional storage to the project. Multiply the number of end caps (EC) by the storage volume per end cap (ECS) to determine the additional storage (As) provided by the end caps. As = EC x ECs 5) Adjust number of chambers (C) to account for additional end cap storage (As). The original number of chambers (C) can now be reduced due to the additional storage in the end caps. Divide the additional storage (As) by the storage volume per chamber to determine the number of chambers that can be removed. Number of chambers to remove = As/ volume per chamber NOTE: Additional storage exists in the stone perimeter as well as in the inlet and outlet manifold systems. Contact StormTech’s Technical Services Department for assistance with determining the number of chambers and end caps required for your project. 8) Determine the volume of excavation (Ex) required. Each additional foot of cover will add a volume of excavation of 1.9 yd3 (1.5 m3) per MC-3500 chamber and 0.6 yd3 (0.5 m3) per MC-3500 end cap. 21 2) Determine the number of chambers (C) required. To calculate the number of chambers required for adequate storage, divide the storage volume (Vs) by the storage volume of the chamber (from Table 14), as follows: C = Vs / Storage Volume per Chamber 3) Determine the number of end caps required. The number of end caps (EC) required depends on the number of rows required by the project. Once the number of chamber rows is determined, multiply the number of chamber rows by 2 to determine the number of end caps required. EC = No. of Chamber Rows x 2 NOTE: Additional end caps may be required for systems having inlet locations within the chamber bed. 4) Determine additional storage provided by end caps. End Caps will provide additional storage to the project. Multiply the number of end caps (EC) by the storage volume per end cap (ECS) to determine the additional storage (As) provided by the end caps. As = EC x ECs 5) Adjust number of chambers (C) to account for additional end cap storage (As). The original number of chambers (C) can now be reduced due to the additional storage in the end caps. Divide the additional storage (As) by the storage volume per chamber to determine the number of chambers that can be removed. Number of chambers to remove = As/ volume per chamber NOTE: Additional storage exists in the stone perimeter as well as in the inlet and outlet manifold systems. Contact StormTech’s Technical Services Department for assistance with determining the number of chambers and end caps required for your project. 6) Determine the required bed size (S). The size of the bed will depend on the number of chambers and end caps required: MC-7200 area per chamber = 59.9 ft2 (5.6 m2) MC-7200 area per end cap = 33.9 ft2 (3.1 m2) S = (C x area per chamber) + (EC x area per end cap) NOTE: It is necessary to add 12” (300 mm) of stone perimeter parallel to the chamber rows and 6” (150 mm) of stone perimeter from the base of all end caps. The additional area due to perimeter stone is not included in the area numbers above. 7) Determine the amount of stone (Vst) required. To calculate the total amount of clean, crushed, angular stone required, multiply the number of chambers (C) and the number of end caps (EC) by the selected weight of stone from Table 15. NOTE: Clean, crushed, angular stone is also required around the perimeter of the system. 8) Determine the volume of excavation (Ex) required. Each additional foot of cover will add a volume of excavation of 2.2 yd3 (1.7 m3) per MC-7200 chamber and 1.4 yd3 (0.8 m3) per MC-7200 end cap. 9) Determine the area of geotextile (F) required. The bottom, top and sides of the bed must be covered with a non-woven geotextile (filter fabric) that meets AASHTO M288 Class 2 requirements. The area of the sidewalls must be calculated and a 24” (600 mm) overlap must be included for all seams. Geotextiles typically come in 15 foot (4.57 m) wide rolls. The following steps provide the calculations necessary for preliminary sizing of an MC-7200 chamber system. For custom bed configurations to fit specific sites, contact the StormTech Technical Services Department or your local StormTech representative. 1) Determine the amount of storage volume (VS) required. It is the design engineer’s sole responsibility to determine the storage volume required. 6.0 MC-7200 Chamber System Sizing Table 14 - Storage Volume Per Chamber/End Cap ft3 (m3) Bare Unit Storage ft3 (m3) Chamber/End Cap and Stone Volume — Stone Foundation Depth in. (mm) 9 (230)12 (300)15 (375)18 (450) MC-7200 Chamber 175.9 (4.98)267.3 (7.57)273.3 (7.74)279.3 (7.91)285.2 (8.08) MC-7200 End Cap 39.5 (1.12)115.3 (3.26)118.6 (3.36)121.9 (3.45)125.29 (3.54) NOTE: Assumes 9” (230 mm) row spacing, 40% stone porosity, 12” (300 mm) stone above and includes the bare chamber/end cap volume. End cap volume assumes 12” (300 mm) stone perimeter.Table 15 - Amount of Stone Per Chamber/End Cap ENGLISH tons (yd3) Stone Foundation Depth 9”12”15”18” Chamber 11.9 (8.5)12.6 (9.0)13.4 (9.6)14.6 (10.1) End Cap 9.8 (7.0)10.2 (7.3)10.6 (7.6)11.1 (7.9) METRIC kg (m3)230 mm 300 mm 375 mm 450 mm Chamber 10796 (6.5)11431 (6.9)12156 (7.3)13245 (7.7) End Cap 8890 (5.3)9253 (5.5)9616 (5.8)10069 (6.0) NOTE: Assumes 12” (300 mm) of stone above, and 9” (230 mm) row spacing, and 12” (300 mm) of perimeter stone in front of end caps. Table 13- Volume of Excavation Per Chamber/End Cap yd3 (m3) Stone Foundation Depth 9” (230 mm)12” (300 mm)15” (375 mm)18” (450 mm) Chamber 17.2 (13.2)17.7 (13.5)18.3 (14.0)18.8 (14.4) End Cap 9.7 (7.4)10.0 (7.6)10.3 (7.9)10.6 (8.1) NOTE: Assumes 9” (230 mm) separation between chamber rows, 12” (300 mm) of perimeter in front of end caps, and 24” (600 mm) of cover. The volume of excavation will vary as the depth of cover increases. 22 7.0 Structural Cross Sections and Specifications MC-3500 Stormwater Chamber Specifications 1. Chambers shall be StormTech MC-3500 or approved equal. 2. Chambers shall be made from virgin, impact-modified polypropylene copolymers. 3. Chamber rows shall provide continuous, unobstructed internal space with no internal panels that would impede flow. 4. The structural design of the chambers, the structural backfill and the installation requirements shall ensure that the load factors specified in the AASHTO LRFD Bridge Design Specifications, Section 12.12 are met for: 1) long-duration dead loads and 2) short-duration live loads, based on the AASHTO Design Truck with consideration for impact and multiple vehicle presences. 5. Chambers shall meet the requirements of ASTM F 2418, “Standard Specification for Polypropylene (PP) Corrugated Wall Stormwater Collection Chambers.” 6. Chambers shall conform to the requirements of ASTM F 2787, “Standard Practice for Structural Design of Thermoplastic Corrugated Wall Stormwater Collection Chambers.” Figure 16A - MC-3500 Structural Cross Section Detail (Not to Scale) 7. Only chambers that are approved by the engineer will be allowed. The contractor shall submit (3 sets) of the following to the engineer for approval before delivering chambers to the project site: • A structural evaluation by a registered structural engineer that demonstrates that the load factors specified in the AASHTO LRFD Bridge Design Specifications, Section 12.12 are met. The 50-year creep modulus data specified in ASTM F 2418 must be used as part of the AASHTO structural evaluation to verify long-term performance. • Structural cross section detail on which the structural cross section is based. 8. The installation of chambers shall be in accordance with the manufacturer’s latest Construction Guide. Detail drawings available in Cad Rev. 2000 format at www.stormtech.com 45"(1140 mm) 18"(450 mm) MIN* 8'(2.4 m)MAX 12" (300 mm) TYP77" (1950 mm) 12" (300 mm) MIN 6"(150 mm) MIN DEPTH OF STONE TO BE DETERMINEDBY SITE DESIGN ENGINEER 9" (230 mm) MIN6" (150 mm) MIN MC-3500END CAP PERIMETER STONE EXCAVATION WALL(CAN BE SLOPEDOR VERTICAL) PAVEMENT LAYER (DESIGNEDBY SITE DESIGN ENGINEER) CHAMBERS SHALL BE BE DESIGNED IN ACCORDANCE WITH ASTM F2787"STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTICCORRUGATED WALL STORMWATER COLLECTION CHAMBERS". GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35%FINES, COMPACT IN 12" (300 mm) MAX LIFTS TO 95% PROCTORDENSITY. SEE THE TABLE OF ACCEPTABLE FILL MATERIALS. ADS GEOSYTHETICS 601T NON-WOVENGEOTEXTILE ALL AROUND CLEAN, CRUSHED,ANGULAR EMBEDMENT STONE CHAMBERS SHALL MEET ASTM F2418 "STANDARDSPECIFICATION FOR POLYPROPLENE (PP) CORRUGATEDWALL STORMWATER COLLECTION CHAMBERS". EMBEDMENT STONE SHALL BE A CLEAN, CRUSHED AND ANGULARSTONE WITH AN AASHTO M43 DESIGNATION BETWEEN #3 AND #4 SITE DESIGN ENGINEER IS RESPONSIBLE FOR ENSURINGTHE REQUIRED BEARING CAPACITY OF SOILS *MINIMUM COVER TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR, INCREASE COVER TO 24" (600 mm). Special applications will be considered on a project by project basis. Please contact our application department should you have a unique application for our team to evaluate. Detail drawings available in Cad Rev. 2000 format at www.stormtech.com Special applications will be considered on a project by project basis. Please contact our application department should you have a unique application for our team to evaluate. 23 7.0 Structural Cross Sections and Specifications MC-7200 Stormwater Chamber Specifications 1. Chambers shall be StormTech MC-7200 or approved equal. 2. Chambers shall be made from virgin, impact- modified polypropylene copolymers. 3. Chamber rows shall provide continuous, unobstructed internal space with no internal panels that would impede flow. 4. The structural design of the chambers, the structural backfill and the installation requirements shall ensure that the load factors specified in the AASHTO LRFD Bridge Design Specifications, Section 12.12 are met for: 1) long- duration dead loads and 2) short-duration live loads, based on the AASHTO Design Truck with consideration for impact and multiple vehicle presences. 5. Chambers shall meet the requirements of ASTM F 2418, “Standard Specification for Polypropylene (PP) Corrugated Wall Stormwater Collection Chambers.” 6. Chambers shall conform to the requirements of ASTM F 2787, “Standard Practice for Structural Design of Thermoplastic Corrugated Wall Stormwater Collection Chambers.” Figure 16B - MC-7200 Structural Cross Section Detail (Not to Scale) 7. Only chambers that are approved by the engineer will be allowed. The contractor shall submit (3 sets) of the following to the engineer for approval before delivering chambers to the project site: • A structural evaluation by a registered structural engineer that demonstrates that the load factors specified in the AASHTO LRFD Bridge Design Specifications, Section 12.12 are met. The 50-year creep modulus data specified in ASTM F 2418 must be used as part of the AASHTO structural evaluation to verify long-term performance. • Structural cross section detail on which the structural cross section is based. 8. The installation of chambers shall be in accordance with the manufacturer’s latest Construction Guide. 24 8.0 General Notes 1. StormTech requires installing contractors to use and understand the latest StormTech MC-3500 and MC-7200 Construction Guides prior to beginning system installation. 2. StormTech offers installation consultations to installing contractors. Contact our Technical Service Department or local StormTech representative at least 30 days prior to system installation to arrange a pre-installation consultation. Our representatives can then answer questions or address comments on the StormTech chamber system and inform the installing contractor of the minimum installation requirements before beginning the system’s construction. Call 860-529- 8188 to speak to a Technical Service Representative or visit www.stormtech.com to receive a copy of our Construction Guide. 3. StormTech requirements for systems with pavement design (asphalt, concrete pavers, etc.): Minimum cover is 18” (450mm) for the MC-3500 and 24”(600mm) for the MC-7200 not including pavement; MC-3500 maximum cover is 8.0’ (1.98 m) and MC-7200 maximum cover is 7.0’ (2.43 m) both including pavement. For designs with cover depths deeper than these maximums, please contact Stormtech. For installations that do not include pavement, where rutting from vehicles may occur, minimum required cover is increased to 30” (762 mm). 4. The contractor must report any discrepancies with the bearing capacity of the subgrade materials to the design engineer. 5. AASHTO M288 Class 2 non-woven geotextile (ADS601 or equal) (filter fabric) must be used as indicated in the project plans. 6. Stone placement between chamber rows and around perimeter must follow instructions as indicated in the most current version of StormTech MC-3500 / MC-7200 Construction Guides. 7. Backfilling over the chambers must follow require- ments as indicated in the most current version of StormTech MC-3500 / MC-7200 Construction Guides. 8. The contractor must refer to StormTech MC-3500 / MC-7200 Construction Guides for a Table of Acceptable Vehicle Loads at various depths of cover. This information is also available at the StormTech website: www.stormtech.com. The contractor is responsible for preventing vehicles that exceed StormTech requirements from traveling across or parking over the stormwater system. Temporary fencing, warning tape and appropriately located signs are commonly used to prevent unauthorized vehicles from entering sensitive construction areas. 9. The contractor must apply erosion and sediment control measures to protect the stormwater system during all phases of site construction per local codes and design engineer’s specifications. 10. STORMTECH PRODUCT WARRANTY IS LIMITED. Contact StormTech for warranty information. 25 9.0 Inspection and Maintenance Flamp (Flared End Ramp) A typical JetVac truck (This is not a StormTech product.) Examples of culvert cleaning nozzles appropriate for Isolator Row Plus maintenance. (These are not StormTech products). 9.1 Isolator Row Plus Inspection Regular inspection and maintenance are essential to assure a properly functioning stormwater system. Inspection is easily accomplished through the manhole or optional inspection ports of an Isolator Row Plus. Please follow local and OSHA rules for a confined space entry. Inspection ports can allow inspection to be accomplished completely from the surface without the need for a con- fined space entry. Inspection ports provide visual access to the system with the use of a flashlight. A stadia rod may be inserted to determine the depth of sediment. If upon visual inspection it is found that sediment has accumulated to an average depth exceeding 3” (76 mm), cleanout is required. A StormTech Isolator Row Plus should initially be inspected immediately after completion of the site’s construction. While every effort should be made to prevent sediment from entering the system during construction, it is during this time that excess amounts of sediments are most likely to enter any stormwater system. Inspection and maintenance, if necessary, should be performed prior to passing responsibility over to the site’s owner. Once in normal service, a StormTech Isolator Row Plus should be inspected bi-annually until an understanding of the sites characteristics is developed. The site’s maintenance manager can then revise the inspection schedule based on experience or local requirements. 9.2 Isolator Row Plus Maintenance JetVac maintenance is recommended if sediment has been collected to an average depth of 3” (76 mm) inside the Isolator Row Plus. More frequent maintenance may be required to maintain minimum flow rates through the Isolator Row Plus. The JetVac process utilizes a high pressure water nozzle to propel itself down the Isolator Row Plus while scouring and suspending sediments. As the nozzle is retrieved, a wave of suspended sediments is flushed back into the manhole for vacuuming. Most sewer and pipe maintenance companies have vacuum/ JetVac combi- nation vehicles. Fixed nozzles designed for culverts or large diameter pipe cleaning are preferable. Rear facing jets with an effective spread of at least 45” (1143 mm) are best. StormTech recommends a maximum nozzle pressure of 2000 psi be utilized during cleaning. The JetVac process shall only be performed on StormTech Rows that have ADS Plus fabric over the foundation stone. A Flamp (flared end ramp) is attached to the inlet pipe on the inside of the chamber end cap to provide a smooth transition from pipe invert to fabric bottom. It is configured to improve chamber function performance over time by distributing sediment and debris that would otherwise collect at the inlet. It also serves to improve the fluid and solid flow back into the inlet pipe during maintenance and cleaning, and to guide cleaning and inspection equipment back into the inlet pipe when complete. ADS “Terms and Conditions of Sale” are available on the ADS website, www.ads-pipe.comAdvanced Drainage Systems, the ADS logo and the Green Stripe are registered trademarks of Advanced Drainage Systems, Inc.StormTech® and the Isolator® Row PLUS are registered trademarks of StormTech, Inc. © 2022 Advanced Drainage Systems, Inc. #11116 3/22 CS StormTech provides state-of-the-art products and services that meet or exceed industry performance standards and expectations. We offer designers, regulators, owners and contractors the highest quality products and services for stormwater management that Saves Valuable Land and Protects Water Resources. A Family of Products and Services for the Stormwater Industry: adspipe.com 800-821-6710 MC-3500 and MC-7200 Chambers and End Caps SC-160LP, SC-310 and SC-740 Chambers & End Caps DC-780 Chambers and End Caps Fabricated End Caps Fabricated Manifold Fittings Patented Isolator Row PLUS for Maintenance and Water Quality Chamber Separation Spacers In-House System Layout Assistance On-Site Educational Seminars Worldwide Technical Sales Group Centralized Product Applications Department Research and Development Team Technical Literature, O&M Manuals and Detailed CAD drawings all downloadable via our Website MC-7200 MC-3500 DC-780 SC-740 SC-310 SC-160LP Appendix B – Engineering Calculations Figure 16 Conveyance Map Figure 16.1-16.5 Conveyance Profile Plots Figure 17 25-Year Pipe Analysis Table Figure 18 25-Year Site Outfalls Figure 19 25-Year Junction Analysis Table Figure 20 25-Year Sub-Basin Summary Figure 21 WWHM2012 Water Quality Sizing Report Figure 22 Stormtech Chamber Sizing Calculations Figure 23 Pond “B” Hydrology Analysis Figure 24 Drainage Basin Map Figure 25 Longacres Pond Area Figure 26a Cut/Fill Heat Map Figure 26b Flood Mitigation Heat Map Figure 27 Filtera Bioscape Product Sheet SCALE 1"=100'Conveyance MapFIGURE 16XΔSSxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxS WxWxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxZONEAESDxSDxSDxSDxSDxSDxSDx S D xSDxS Wx SDxSDxSDxSDxWxWxWxWx201819212115201617181921 202120181921 WETLAND APOND B100 YEARFLOODPLAINELEVATIONLOT LINEADJUSTMENTFOR SOUNDERSHEADQUARTERSUNDER FIELD FLOODMITIGATION STORAGEFLOOD MITIGATIONDISCHARGELOCATIONUNDER FIELD FLOODMITIGATION STORAGEUNDER FIELD FLOODMITIGATION STORAGENEWELEVATEDPATIOUNDER FIELDPERFORATEDDRAINAGE (TYP)BIOPOD STORMWATERTREATMENT FACILITYFLOODMITIGATIONDISCHARGELOCATIONSITESTORMWATERDISCHARGELOCATIONNEW STORAGEFACILITYProfile AProfile BProfile CProfile D FIGURE 16.1 Profile Plot A FIGURE 16.2 Profile Plot B FIGURE 16.3 Profile Plot C FIGURE 16.4 Profile Plot D OHPx OHPx OHPx OHPx OHPx OHTx OHPxOHPxOHPx OHPx OHPx OHPx OHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxSSxSSxSSxSSxSSx SSx SSx S S x S S xSSxSSxSSxSSxSSxSSxSDx SDxSDxSDx SDx SDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSDxWxWxWxWxWxWxWxWxWxWxWx Wx WxWxWxWxWxWxWx Wx Wx W xWxWx WxWxWxWxWxWxWxWxWxSDx SDx SDx SDx SDxSDxSDxSDxSDxSDx SDx S D x SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxWxSDx SDx SDx SDxWxWx 20181921 2021151520161616171819211515201616161718212018192120181921201718192120192120192120212021161718202120171819212019212021 OHPx OHPx OHPx OHPx OHPx OHTx OHPxOHPxOHPx OHPx OHPx OHPx OHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxSSxSSxSSxSSxSSx SSx SSx S S x S S xSSxSSxSSxSSxSSxSSxSDx SDxSDxSDx SDx SDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSDxWxWxWxWxWxWxWxWxWxWxWx Wx WxWxWxWxWxWxWx Wx Wx W xWxWx WxWxWxWxWxWxWxWxWxSDx SDx SDx SDx SDxSDxSDxSDxSDxSDx SDx S D x SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxWxSDx SDx SDx SDxWxWx OHPx OHPx OHPx OHPx OHPx OHTx OHPxOHPxOHPx OHPx OHPx OHPx OHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxSSxSSxSSxSSxSSx SSx SSx S S x S S xSSxSSxSSxSSxSSxSSxSDx SDxSDxSDx SDx SDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSDxWxWxWxWxWxWxWxWxWxWxWx Wx WxWxWxWxWxWxWx Wx Wx W xWxWx WxWxWxWxWxWxWxWxWxSDx SDx SDx SDx SDxSDxSDxSDxSDxSDx SDx S D x SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxWxSDx SDx SDx SDxWxWx SUB-09 1.632 ac SUB-10 1.633 ac SUB-08 8.47 acSUB-02 1.063 ac SUB-03 1.436 ac SUB-01 2.281 ac SUB-04 1.072 ac SUB-05 1.155 ac SUB-06 1.21 ac SUB-07 2.375 ac Tc=15.00 Max Length=1011' Avg Slope=0.6 Tc=10.00 Max Length=490' Avg Slope=0.4 Tc=10.00 Max Length=500' Avg Slope=0.4 Tc=10.00 Max Length=656' Avg Slope=0.5 Sub Basins 01-06 Have Minimum 6.33 Min Tc SCALE 1"=100' Sub-Basin and Tc Map FIGURE 16.5 The Time of Concentration for each sub-basin was determined by the King County Surface Drainage Manual section 3.2.1 for Rational Method analysis. Each basin was segmented into sheet flow and channel flow lengths with slopes and surface runoff coefficients determined from the site survey. From KCSDM 3.2.1, segment velocities were assigned and time of concentrations were added to determine the total time of concentration for each sub-basin. Each Tc was user inputted into SSA for hydraulic modeling purposes. Rainfall intensity follows the KCSDM 3.2.1 IDF curve formula, however fully calculated within SSA. The intensity assigned to each Sub-basin is determined by the following equation: i=B/Tc+D)^E. The inputs for the IDF curve are named differently however follow the below descriptions. B= coefficient ar from KCSDM 3.2.1 Tc=Time of concentration for Sub-Basin D= 0 - For basins less than 10 acres, the rational method can be used with does not utilize the D coefficient. E= coefficient br from KCSDM 3.2.1 SN Element Description From (Inlet) To (Outlet) Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap Lengthening Peak Time of Max Travel Design Max Flow / Max Total MaxReported ID Node Node Invert Invert Invert Invert Drop Slope Shape Diameter Width Roughness Losses Losses Losses Flow Gate Factor Flow Peak Flow Time Flow Design Flow Flow Depth / Time Flow Condition Elevation Offset Elevation Offset or Height Flow Velocity Capacity Ratio Total Depth Surcharged Depth Occurrence Ratio (ft) (ft) (ft) (ft) (ft) (ft) (%) (inches) (inches)(cfs) (cfs) (days hh:mm) (ft/sec) (min) (cfs) (min) (ft) 1 Link-01 Out-1Pipe - (8) # 77 37.17 15.21 0.00 12.20 0.00 3.01 8.1000 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 5.21 0 00:08 4.07 0.15 25.91 0.20 0.68 0.00 1.02 Calculated 2 Link-02 Out-1Pipe - (59) # 77 37.50 15.21 0.00 12.20 0.00 3.01 8.0300 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 3.19 0 00:10 5.26 0.12 25.79 0.12 0.62 0.00 0.93 Calculated 3 Link-03 SD D04 Out-1Pipe - (52) 91.70 9.19 0.00 8.73 4.20 0.46 0.5000 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 2.64 0 00:10 3.36 0.45 2.73 0.96 1.00 1432.00 1.00 SURCHARGED 4 Pipe - (13) SD A01 SD A02 232.60 16.85 0.00 16.27 0.00 0.58 0.2500 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 2.61 0 00:06 2.16 1.79 5.68 0.46 0.77 0.00 1.16 Calculated 5 Pipe - (23) SD C06 Out-1Pipe - (23) 77.91 9.01 0.00 8.95 0.00 0.06 0.0800 CIRCULAR 24.000 24.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 8.96 0 00:13 2.85 0.46 10.96 0.82 1.00 1430.00 2.00 SURCHARGED 6 Pipe - (32) SD B02 SD B03 111.70 16.30 0.00 15.74 0.00 0.56 0.5000 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 3.21 0 00:10 4.10 0.45 2.73 1.17 0.98 0.00 0.98 > CAPACITY 7 Pipe - (42) SD C02 SD C03 42.70 11.82 0.00 11.61 0.00 0.21 0.5000 CIRCULAR 24.000 24.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 8.35 0 00:13 3.30 0.22 17.27 0.48 1.00 1427.00 2.00 SURCHARGED 8 Pipe - (43) SD C01 SD C02 18.29 11.91 0.00 11.82 0.00 0.09 0.5000 CIRCULAR 24.000 24.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 7.19 0 00:13 2.87 0.11 17.38 0.41 1.00 1427.00 2.00 SURCHARGED 9 Pipe - (48) SD D01 SD D02 111.35 13.80 0.00 12.66 0.00 1.14 1.0200 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 2.63 0 00:10 3.35 0.55 3.91 0.67 1.00 11.00 1.00 SURCHARGED 10 Pipe - (49) SD D02 SD D03 161.38 12.66 0.00 11.08 0.00 1.58 0.9800 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 2.63 0 00:10 3.61 0.75 3.82 0.69 1.00 1431.00 1.00 SURCHARGED 11 Pipe - (5) SD C05 SD C06 35.67 9.19 0.00 9.01 0.00 0.18 0.5000 CIRCULAR 24.000 24.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 8.88 0 00:13 2.83 0.21 17.41 0.51 1.00 1429.00 2.00 SURCHARGED 12 Pipe - (50) SD D03 SD D04 188.82 11.08 0.00 9.19 0.00 1.89 1.0000 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 2.64 0 00:10 3.60 0.87 3.86 0.68 1.00 1431.00 1.00 SURCHARGED 13 Pipe - (55) SD B01 SD B02 85.72 16.75 0.00 16.30 0.00 0.45 0.5200 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 3.21 0 00:10 4.08 0.35 2.80 1.15 1.00 6.00 1.00 SURCHARGED 14 Pipe - (56) # 79 SD B01 21.78 16.85 0.00 16.75 0.00 0.10 0.4600 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 1.81 0 00:06 3.01 0.12 2.62 0.69 1.00 6.00 1.00 SURCHARGED 15 Pipe - (57) # 80 SD B01 45.76 16.85 0.00 16.75 0.00 0.10 0.2200 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 1.80 0 00:10 2.29 0.33 1.80 1.00 1.00 7.00 1.00 SURCHARGED 16 Pipe - (58) # 77 Out-1Pipe - (58) 47.79 12.20 0.00 12.04 0.00 0.16 0.3300 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 8.02 0 00:10 4.54 0.18 6.58 1.22 1.00 1435.00 1.50 SURCHARGED 17 Pipe - (59) SD B03 Out-1Pipe - (59) 30.06 15.74 0.00 15.21 0.00 0.53 1.7600 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 3.20 0 00:10 4.46 0.11 15.11 0.21 0.44 0.00 0.66 Calculated 18 Pipe - (6) SD C04 SD C05 230.27 10.26 0.00 9.19 0.00 1.07 0.4600 CIRCULAR 24.000 24.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 8.80 0 00:13 3.48 1.10 16.71 0.53 1.00 1428.00 2.00 SURCHARGED 19 Pipe - (6) (1) SD C03 SD C04 287.84 11.61 0.00 10.26 0.00 1.35 0.4700 CIRCULAR 24.000 24.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 8.73 0 00:13 4.14 1.16 16.76 0.52 1.00 1427.00 2.00 SURCHARGED 20 Pipe - (60) # 84 SD D01 165.95 16.05 0.00 13.80 0.00 2.25 1.3600 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 2.16 0 00:09 3.56 0.78 4.49 0.48 1.00 2.00 1.00 SURCHARGED 21 Pipe - (61) # 85 # 86 143.43 15.10 0.00 14.49 0.00 0.61 0.4300 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 0.74 0 00:10 2.40 1.00 2.52 0.29 1.00 4.00 1.00 SURCHARGED 22 Pipe - (61) (1) # 86 SD D01 43.12 14.49 0.00 13.80 0.00 0.69 1.5900 CIRCULAR 12.000 12.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 1.04 0 00:09 1.81 0.40 4.87 0.21 1.00 7.00 1.00 SURCHARGED 23 Pipe - (8) SD A04 Out-1Pipe - (8) 24.70 15.31 0.00 15.21 0.00 0.10 0.4000 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 5.23 0 00:07 4.64 0.09 7.24 0.72 0.63 0.00 0.94 Calculated 24 Pipe - (8) (2) SD A03 SD A04 107.33 15.63 0.00 15.31 0.00 0.32 0.3000 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 5.28 0 00:08 3.16 0.57 6.21 0.85 0.90 0.00 1.35 Calculated 25 Pipe - (9) SD A02 SD A03 256.48 16.27 0.00 15.63 0.00 0.64 0.2500 CIRCULAR 18.000 18.00 0.0120 0.5000 0.5000 0.0000 0.00 NO 1.00 5.58 0 00:07 3.37 1.27 5.68 0.98 0.91 0.00 1.36 Calculated FIGURE 17 25 Year Pipe Analysis Table SSA Output - Shows the analysis of each pipe within the system. The peak flow (Q) shown in this table represents the total combined flow each pipe recieves. Ratio of max flow capacity to actual flow Max capacity for each designed pipe (n)(Q)(V) FIGURE 18 25 Year Site Outfalls SN Element X Coordinate Y Coordinate Description Invert Boundary Flap Fixed Peak Peak Maximum Maximum ID Elevation Type Gate Water Inflow Lateral HGL Depth HGL Elevation Elevation Inflow Attained Attained (ft) (ft) (cfs) (cfs) (ft) (ft) 1 Out-1Pipe - (23) 1293066.04 171095.82 8.95 FIXED YES 14.70 8.96 0.00 5.75 14.70 2 Out-1Pipe - (52) 1293156.36 171500.03 4.53 FIXED YES 14.70 2.64 0.00 10.17 14.70 3 Out-1Pipe - (58) 1293057.20 171297.91 12.04 FIXED YES 14.70 8.02 0.00 2.66 14.70 FIGURE 19 25 Year Junction Analysis Table SN Element X Coordinate Y Coordinate Description Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum Peak Peak Maximum Maximum Maximum Minimum Average Average Time of Time of Total Total ID Elevation (Max) (Max) Water Water Elevation Depth Area Pipe Cover Inflow Lateral HGL HGL Surcharge Freeboard HGL HGL Maximum Peak Flooded Time Elevation Offset Elevation Depth Inflow Elevation Depth Depth Attained Elevation Depth HGL Flooding Volume Flooded Attained Attained Attained Attained Attained Occurrence Occurrence (ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft²) (inches) (cfs) (cfs) (ft) (ft) (ft) (ft) (ft) (ft) (days hh:mm) (days hh:mm) (ac-inches) (minutes) 1 # 77 1293103.92 171287.83 12.20 15.20 3.00 12.20 0.00 15.20 0.00 820.00 18.00 8.28 0.00 15.26 3.06 0.06 0.00 14.69 2.49 0 00:09 0 00:04 0.02 4.00 2 # 79 1293180.51 171065.46 16.85 21.50 4.65 16.85 0.00 21.50 0.00 0.00 43.80 1.81 1.81 18.63 1.78 0.00 2.87 16.86 0.01 0 00:10 0 00:00 0.00 0.00 3 # 80 1293214.74 171041.59 16.85 21.50 4.65 16.85 0.00 21.50 0.00 0.00 43.80 1.80 1.80 18.74 1.89 0.00 2.76 16.86 0.01 0 00:10 0 00:00 0.00 0.00 4 # 84 1293699.69 171831.14 16.05 20.89 4.84 16.05 0.00 20.89 0.00 0.00 46.08 2.12 2.12 20.89 4.84 0.00 0.00 16.06 0.01 0 00:10 0 00:10 0.00 0.00 5 # 85 1293706.95 171873.33 15.10 20.49 5.39 15.10 0.00 20.49 0.00 0.00 52.68 1.37 0.65 20.49 5.39 0.00 0.00 15.11 0.01 0 00:10 0 00:10 0.00 0.00 6 # 86 1293567.81 171838.48 14.49 18.37 3.89 14.49 0.00 18.37 0.00 0.00 34.66 1.60 0.00 18.37 3.88 0.00 0.00 14.70 0.21 0 00:09 0 00:09 0.00 0.00 7 Out-1Pipe - (59) 1293105.54 171250.37 15.21 17.00 1.79 15.21 0.00 17.00 0.00 0.00 3.48 3.20 0.00 15.57 0.36 0.00 1.43 15.21 0.00 0 00:10 0 00:00 0.00 0.00 8 Out-1Pipe - (8) 1293120.64 171321.03 15.21 17.00 1.79 15.21 0.00 17.00 0.00 0.00 3.48 5.23 0.00 15.75 0.54 0.00 1.25 15.21 0.00 0 00:08 0 00:00 0.00 0.00 9 SD A01 1293664.94 171431.84 16.85 21.50 4.65 16.85 0.00 21.50 0.00 0.00 37.80 2.95 2.95 17.78 0.93 0.00 3.72 16.86 0.01 0 00:07 0 00:00 0.00 0.00 10 SD A02 1293432.34 171431.84 16.27 21.50 5.23 16.27 0.00 21.50 0.00 0.00 44.76 6.06 3.47 17.65 1.38 0.00 3.85 16.28 0.01 0 00:07 0 00:00 0.00 0.00 11 SD A03 1293175.86 171431.84 15.63 19.93 4.30 15.63 0.00 19.93 0.00 0.00 33.64 5.58 0.00 17.00 1.37 0.00 2.93 15.64 0.01 0 00:08 0 00:00 0.00 0.00 12 SD A04 1293143.88 171329.39 15.31 19.78 4.47 15.31 0.00 19.78 0.00 0.00 35.69 5.28 0.00 16.65 1.34 0.00 3.13 15.32 0.01 0 00:08 0 00:00 0.00 0.00 13 SD B01 1293169.28 171046.79 16.75 18.77 2.02 16.75 0.00 18.77 0.00 0.00 12.28 3.21 0.00 18.56 1.81 0.00 0.21 16.76 0.01 0 00:10 0 00:00 0.00 0.00 14 SD B02 1293140.35 171127.48 16.30 17.82 1.52 16.30 0.00 17.82 0.00 0.00 6.28 3.21 0.00 17.82 1.52 0.00 0.00 16.31 0.01 0 00:05 0 00:05 0.00 0.00 15 SD B03 1293133.35 171238.97 15.74 21.00 5.26 15.74 0.00 21.00 0.00 0.00 45.12 3.21 0.00 16.71 0.97 0.00 4.29 15.75 0.01 0 00:10 0 00:00 0.00 0.00 16 SD C01 1293696.32 171095.73 11.91 22.08 10.17 11.91 0.00 22.08 0.00 0.00 98.05 6.65 6.65 22.08 10.17 0.00 0.00 14.65 2.74 0 00:13 0 00:13 0.00 0.00 17 SD C02 1293678.04 171095.93 11.82 23.06 11.24 11.82 0.00 23.06 0.00 0.00 110.86 7.19 0.00 22.12 10.30 0.00 0.94 14.65 2.83 0 00:13 0 00:00 0.00 0.00 18 SD C03 1293677.07 171053.24 11.61 21.50 9.89 11.61 0.00 21.50 0.00 0.00 94.73 8.35 0.00 21.50 9.89 0.00 0.00 14.64 3.03 0 00:13 0 00:13 0.00 0.00 19 SD C04 1293389.23 171053.14 10.26 21.50 11.24 10.26 0.00 21.50 0.00 0.00 110.88 8.73 0.00 20.00 9.74 0.00 1.50 14.63 4.37 0 00:12 0 00:00 0.00 0.00 20 SD C05 1293158.97 171053.07 9.19 18.99 9.80 9.19 0.00 18.99 0.00 0.00 93.56 8.80 0.00 16.22 7.03 0.00 2.77 14.62 5.43 0 00:12 0 00:00 0.00 0.00 21 SD C06 1293124.41 171044.22 9.01 18.34 9.33 9.01 0.00 18.34 0.00 0.00 87.96 8.88 0.00 16.37 7.36 0.00 1.97 14.62 5.61 0 00:12 0 00:00 0.00 0.00 22 SD D01 1293535.02 171810.48 13.80 19.91 6.11 13.80 0.00 19.91 0.00 0.00 61.28 2.61 0.00 19.06 5.26 0.00 0.84 14.69 0.89 0 00:09 0 00:00 0.00 0.00 23 SD D02 1293423.67 171810.66 12.66 19.69 7.03 12.66 0.00 19.69 0.00 0.00 72.36 2.63 0.00 19.69 7.03 0.00 0.00 14.68 2.02 0 00:09 0 00:09 0.00 0.00 24 SD D03 1293319.75 171687.20 11.08 19.82 8.74 11.08 0.00 19.82 0.00 0.00 92.88 2.63 0.00 19.82 8.74 0.00 0.00 14.67 3.59 0 00:08 0 00:08 0.00 0.00 25 SD D04 1293219.84 171526.97 9.19 19.73 10.54 9.19 0.00 19.73 0.00 0.00 114.48 2.64 0.00 16.53 7.34 0.00 3.20 14.66 5.47 0 00:08 0 00:00 0.00 0.00 SSA Output - Shows analysis of each structure in the system. Key data output in this table is the Minumum Freeboard Attained, showing that every structure meets the requirement to not overtop the rim during the 25-year 24 hour storm. Calculated by subtracting the Max HGL from the rim elevation to ensure that no rim is overtopped,which is the minimum requirement. FIGURE 20 25 Year Sub-Basin Summary SN Element Description Area Drainage Weighted Accumulated Total Peak Rainfall Time ID Node ID Runoff Precipitation Runoff Runoff Intensity of Coefficient Concentration (acres) (inches) (inches) (cfs) (inches/hr) (days hh:mm:ss) 1 Sub-01 2.28 SD A02 0.6600 0.17 0.11 2.36 1.568 0 00:06:19 2 Sub-02 1.06 SD A01 0.6600 0.17 0.11 1.10 1.568 0 00:06:19 3 Sub-03 1.44 SD A01 0.8200 0.17 0.14 1.85 1.568 0 00:06:19 4 Sub-04 1.07 SD A02 0.6600 0.17 0.11 1.11 1.568 0 00:06:19 5 Sub-05 1.16 # 79 0.6600 0.19 0.13 0.88 1.149 0 00:10:00 6 Sub-06 1.21 # 79 0.6600 0.17 0.11 1.25 1.568 0 00:06:19 7 Sub-07 2.37 # 80 0.6600 0.19 0.13 1.80 1.149 0 00:10:00 8 Sub-08 8.47 SD C01 0.9000 0.22 0.20 6.65 0.872 0 00:15:00 9 Sub-09 2.17 # 84 0.8500 0.19 0.16 2.12 1.149 0 00:10:00 10 Sub-10 1.08 # 85 0.5200 0.19 0.10 0.65 1.149 0 00:10:00 SSA Output - Shows the input sub-basin information including the calculated area, C value. This table shows the flow (Q) entering each catch basin, using the Rational Method (Q=CiA) (A)(C)(Q)(i)(Tc) WWHM2012 PROJECT REPORT 2023-05-01 Sounders FC HQ 5/1/2023 11:14:13 PM Page 2 General Model Information Project Name:2023-05-01 Sounders FC HQ Site Name:Seattle Sounders FC HQ Site Address: City:Renton Report Date:5/1/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2021/08/18 Version:4.2.18 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 2023-05-01 Sounders FC HQ 5/1/2023 11:14:13 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre A B, Forest, Flat 11 Pervious Total 11 Impervious Land Use acre Impervious Total 0 Basin Total 11 Element Flows To: Surface Interflow Groundwater 2023-05-01 Sounders FC HQ 5/1/2023 11:14:13 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 2.7 Pervious Total 2.7 Impervious Land Use acre ROOF TOPS FLAT 0.74 PARKING FLAT 7.56 Impervious Total 8.3 Basin Total 11 Element Flows To: Surface Interflow Groundwater 2023-05-01 Sounders FC HQ 5/1/2023 11:14:13 PM Page 5 Routing Elements Predeveloped Routing 2023-05-01 Sounders FC HQ 5/1/2023 11:14:13 PM Page 6 Mitigated Routing 2023-05-01 Sounders FC HQ 5/1/2023 11:14:13 PM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:11 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:2.7 Total Impervious Area:8.3 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.009334 5 year 0.014126 10 year 0.018027 25 year 0.023885 50 year 0.028991 100 year 0.034793 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 3.183044 5 year 4.036193 10 year 4.617584 25 year 5.373504 50 year 5.953258 100 year 6.54805 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.008 4.111 1950 0.016 4.429 1951 0.017 2.640 1952 0.009 2.279 1953 0.009 2.459 1954 0.009 2.603 1955 0.009 2.918 1956 0.009 2.872 1957 0.009 3.258 1958 0.009 2.628 2023-05-01 Sounders FC HQ 5/1/2023 11:14:38 PM Page 8 1959 0.009 2.681 1960 0.009 2.635 1961 0.009 2.783 1962 0.008 2.424 1963 0.008 2.708 1964 0.009 2.641 1965 0.009 3.376 1966 0.009 2.246 1967 0.009 3.866 1968 0.009 4.396 1969 0.009 3.055 1970 0.008 2.948 1971 0.009 3.516 1972 0.045 3.801 1973 0.009 2.198 1974 0.009 3.208 1975 0.009 3.695 1976 0.009 2.491 1977 0.007 2.691 1978 0.009 3.292 1979 0.007 4.506 1980 0.009 4.043 1981 0.009 3.307 1982 0.009 4.663 1983 0.009 3.795 1984 0.009 2.396 1985 0.009 3.299 1986 0.008 2.860 1987 0.008 4.412 1988 0.009 2.679 1989 0.009 3.348 1990 0.009 6.184 1991 0.014 4.648 1992 0.009 2.371 1993 0.007 2.053 1994 0.008 2.236 1995 0.009 2.933 1996 0.061 3.257 1997 0.009 3.095 1998 0.008 3.072 1999 0.014 6.284 2000 0.008 3.132 2001 0.009 3.437 2002 0.008 4.009 2003 0.009 3.131 2004 0.009 5.880 2005 0.009 2.689 2006 0.009 2.434 2007 0.092 5.632 2008 0.009 4.498 2009 0.009 4.090 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0915 6.2844 2 0.0615 6.1836 3 0.0454 5.8802 2023-05-01 Sounders FC HQ 5/1/2023 11:14:38 PM Page 9 4 0.0166 5.6321 5 0.0164 4.6633 6 0.0143 4.6475 7 0.0142 4.5061 8 0.0089 4.4981 9 0.0089 4.4290 10 0.0089 4.4123 11 0.0089 4.3958 12 0.0089 4.1112 13 0.0088 4.0902 14 0.0088 4.0430 15 0.0088 4.0093 16 0.0088 3.8658 17 0.0088 3.8011 18 0.0088 3.7954 19 0.0088 3.6952 20 0.0088 3.5162 21 0.0088 3.4368 22 0.0088 3.3757 23 0.0088 3.3477 24 0.0088 3.3070 25 0.0088 3.2994 26 0.0088 3.2918 27 0.0087 3.2577 28 0.0087 3.2575 29 0.0087 3.2076 30 0.0087 3.1316 31 0.0087 3.1312 32 0.0086 3.0950 33 0.0086 3.0715 34 0.0086 3.0554 35 0.0086 2.9484 36 0.0086 2.9325 37 0.0086 2.9179 38 0.0086 2.8716 39 0.0086 2.8597 40 0.0086 2.7828 41 0.0086 2.7084 42 0.0086 2.6910 43 0.0086 2.6886 44 0.0085 2.6807 45 0.0085 2.6790 46 0.0085 2.6410 47 0.0085 2.6402 48 0.0085 2.6350 49 0.0085 2.6282 50 0.0084 2.6033 51 0.0084 2.4908 52 0.0083 2.4594 53 0.0083 2.4342 54 0.0083 2.4244 55 0.0083 2.3963 56 0.0082 2.3710 57 0.0082 2.2794 58 0.0078 2.2457 59 0.0074 2.2357 60 0.0069 2.1981 61 0.0069 2.0535 2023-05-01 Sounders FC HQ 5/1/2023 11:14:38 PM Page 10 2023-05-01 Sounders FC HQ 5/1/2023 11:14:38 PM Page 11 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.0047 3035 408312 13453 Fail 0.0049 2710 403393 14885 Fail 0.0052 2387 398901 16711 Fail 0.0054 2141 394409 18421 Fail 0.0056 1913 390346 20404 Fail 0.0059 1684 386496 22951 Fail 0.0061 1475 382646 25942 Fail 0.0064 1329 379010 28518 Fail 0.0066 1172 375587 32046 Fail 0.0069 1007 370668 36809 Fail 0.0071 840 367460 43745 Fail 0.0074 671 364465 54316 Fail 0.0076 552 361471 65483 Fail 0.0079 442 358476 81103 Fail 0.0081 352 355910 101110 Fail 0.0084 250 353129 141251 Fail 0.0086 128 350562 273876 Fail 0.0088 36 347996 966655 Fail 0.0091 26 345429 1328573 Fail 0.0093 26 343076 1319523 Fail 0.0096 26 340937 1311296 Fail 0.0098 26 338585 1302250 Fail 0.0101 25 336446 1345784 Fail 0.0103 25 334307 1337228 Fail 0.0106 24 332168 1384033 Fail 0.0108 23 330243 1435839 Fail 0.0111 23 328318 1427469 Fail 0.0113 23 326393 1419100 Fail 0.0115 22 324468 1474854 Fail 0.0118 22 322757 1467077 Fail 0.0120 22 321046 1459300 Fail 0.0123 21 319121 1519623 Fail 0.0125 21 317410 1511476 Fail 0.0128 21 315699 1503328 Fail 0.0130 21 314201 1496195 Fail 0.0133 19 312490 1644684 Fail 0.0135 19 310993 1636805 Fail 0.0138 18 309496 1719422 Fail 0.0140 18 307999 1711105 Fail 0.0142 18 306502 1702788 Fail 0.0145 16 305004 1906275 Fail 0.0147 16 303507 1896918 Fail 0.0150 16 302010 1887562 Fail 0.0152 16 300727 1879543 Fail 0.0155 16 299443 1871518 Fail 0.0157 15 297946 1986306 Fail 0.0160 15 296663 1977753 Fail 0.0162 15 295379 1969193 Fail 0.0165 14 294096 2100685 Fail 0.0167 13 292813 2252407 Fail 0.0170 13 291743 2244176 Fail 0.0172 13 290460 2234307 Fail 0.0174 13 289177 2224438 Fail 0.0177 13 288107 2216207 Fail 2023-05-01 Sounders FC HQ 5/1/2023 11:14:38 PM Page 12 0.0179 13 286824 2206338 Fail 0.0182 12 285754 2381283 Fail 0.0184 12 284685 2372375 Fail 0.0187 12 283402 2361683 Fail 0.0189 11 282332 2566654 Fail 0.0192 11 281263 2556936 Fail 0.0194 11 280193 2547209 Fail 0.0197 11 279124 2537490 Fail 0.0199 10 278054 2780540 Fail 0.0201 10 276985 2769850 Fail 0.0204 9 276129 3068100 Fail 0.0206 9 275060 3056222 Fail 0.0209 9 273991 3044344 Fail 0.0211 9 273135 3034833 Fail 0.0214 9 272066 3022955 Fail 0.0216 8 271210 3390125 Fail 0.0219 8 270141 3376762 Fail 0.0221 8 269285 3366062 Fail 0.0224 8 268429 3355362 Fail 0.0226 8 267574 3344675 Fail 0.0228 8 266504 3331300 Fail 0.0231 8 265649 3320612 Fail 0.0233 8 264793 3309912 Fail 0.0236 8 263938 3299225 Fail 0.0238 8 263082 3288525 Fail 0.0241 8 262227 3277837 Fail 0.0243 8 261371 3267137 Fail 0.0246 8 260516 3256450 Fail 0.0248 8 259660 3245750 Fail 0.0251 8 259018 3237725 Fail 0.0253 8 258163 3227037 Fail 0.0256 8 257307 3216337 Fail 0.0258 8 256452 3205650 Fail 0.0260 8 255810 3197625 Fail 0.0263 8 254954 3186925 Fail 0.0265 8 254099 3176237 Fail 0.0268 8 253457 3168212 Fail 0.0270 8 252602 3157525 Fail 0.0273 8 251960 3149500 Fail 0.0275 8 251105 3138812 Fail 0.0278 8 250463 3130787 Fail 0.0280 8 249821 3122762 Fail 0.0283 8 249180 3114750 Fail 0.0285 8 248324 3104050 Fail 0.0287 8 247682 3096025 Fail 0.0290 8 246827 3085337 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. 2023-05-01 Sounders FC HQ 5/1/2023 11:14:38 PM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.9956 acre-feet On-line facility target flow:1.3192 cfs. Adjusted for 15 min:1.3192 cfs. Off-line facility target flow:0.7454 cfs. Adjusted for 15 min:0.7454 cfs. 2023-05-01 Sounders FC HQ 5/1/2023 11:14:38 PM Page 14 LID Report 2023-05-01 Sounders FC HQ 5/1/2023 11:14:45 PM Page 15 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. 2023-05-01 Sounders FC HQ 5/1/2023 11:14:45 PM Page 16 Appendix Predeveloped Schematic 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 17 Mitigated Schematic 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 18 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 2023-05-01 Sounders FC HQ.wdm MESSU 25 Pre2023-05-01 Sounders FC HQ.MES 27 Pre2023-05-01 Sounders FC HQ.L61 28 Pre2023-05-01 Sounders FC HQ.L62 30 POC2023-05-01 Sounders FC HQ1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 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 *** 1 A/B, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 1 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 ********* 1 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 19 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 1 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 1 0 5 2 400 0.05 0.3 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 1 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 1 0.2 0.5 0.35 0 0.7 0.7 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 1 0 0 0 0 3 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 20 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 1 11 COPY 501 12 PERLND 1 11 COPY 501 13 ******Routing****** 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 *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 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 * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 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 <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES 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 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 21 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** 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 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 END MASS-LINK END RUN 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 22 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 2023-05-01 Sounders FC HQ.wdm MESSU 25 Mit2023-05-01 Sounders FC HQ.MES 27 Mit2023-05-01 Sounders FC HQ.L61 28 Mit2023-05-01 Sounders FC HQ.L62 30 POC2023-05-01 Sounders FC HQ1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 7 IMPLND 4 IMPLND 11 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 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 END GEN-INFO *** 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 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 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 23 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 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 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 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 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 7 0 0 0 0 3 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 4 ROOF TOPS/FLAT 1 1 1 27 0 11 PARKING/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 4 0 0 1 0 0 0 11 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 4 0 0 4 0 0 0 1 9 11 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 *** 4 0 0 0 0 0 11 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 4 400 0.01 0.1 0.1 11 400 0.01 0.1 0.1 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 24 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 4 0 0 11 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 4 0 0 11 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 7 2.7 COPY 501 12 PERLND 7 2.7 COPY 501 13 IMPLND 4 0.74 COPY 501 15 IMPLND 11 7.56 COPY 501 15 ******Routing****** 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 *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 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 * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 25 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 <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES 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 END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** 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 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 END MASS-LINK END RUN 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 26 Predeveloped HSPF Message File 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 27 Mitigated HSPF Message File 2023-05-01 Sounders FC HQ 5/1/2023 11:14:46 PM Page 28 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. 2005-2023; 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 ©2022 ADS, INC. PROJECT INFORMATION ADS SALES REP: ENGINEERED PRODUCT MANAGER: PROJECT NO: SEATTLE SOUNDERS FC HQ & TRAINING CENTER RENTON, WA CHARLIE CLICK 360-450-1932 CHARLIE.CLICK@ADSPIPE.COM S303454 Advanced Drainage Systems, Inc. AVERY SCOTT 971-227-0854 AVERY.SCOTT@ADSPIPE.COM MC-3500 STORMTECH CHAMBER SPECIFICATIONS 1.CHAMBERS SHALL BE STORMTECH MC-3500. 2.CHAMBERS SHALL BE ARCH-SHAPED AND SHALL BE MANUFACTURED FROM VIRGIN, IMPACT-MODIFIED POLYPROPYLENE COPOLYMERS. 3.CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED WALL STORMWATER COLLECTION CHAMBERS" CHAMBER CLASSIFICATION 45x76 DESIGNATION SS. 4.CHAMBER ROWS SHALL PROVIDE CONTINUOUS, UNOBSTRUCTED INTERNAL SPACE WITH NO INTERNAL SUPPORTS THAT WOULD IMPEDE FLOW OR LIMIT ACCESS FOR INSPECTION. 5.THE STRUCTURAL DESIGN OF THE CHAMBERS, THE STRUCTURAL BACKFILL, AND THE INSTALLATION REQUIREMENTS SHALL ENSURE THAT THE LOAD FACTORS SPECIFIED IN THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS, SECTION 12.12, ARE MET FOR: 1) LONG-DURATION DEAD LOADS AND 2) SHORT-DURATION LIVE LOADS, BASED ON THE AASHTO DESIGN TRUCK WITH CONSIDERATION FOR IMPACT AND MULTIPLE VEHICLE PRESENCES. 6.CHAMBERS SHALL BE DESIGNED, TESTED AND ALLOWABLE LOAD CONFIGURATIONS DETERMINED IN ACCORDANCE WITH ASTM F2787, "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". LOAD CONFIGURATIONS SHALL INCLUDE: 1) INSTANTANEOUS (<1 MIN) AASHTO DESIGN TRUCK LIVE LOAD ON MINIMUM COVER 2) MAXIMUM PERMANENT (75-YR) COVER LOAD AND 3) ALLOWABLE COVER WITH PARKED (1-WEEK) AASHTO DESIGN TRUCK. 7.REQUIREMENTS FOR HANDLING AND INSTALLATION: ·TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING STACKING LUGS. ·TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS THAN 3”. ·TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT SHALL BE GREATER THAN OR EQUAL TO 450 LBS/FT/%. THE ASC IS DEFINED IN SECTION 6.2.8 OF ASTM F2418. AND b) TO RESIST CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73° F / 23° C), CHAMBERS SHALL BE PRODUCED FROM REFLECTIVE GOLD OR YELLOW COLORS. 8.ONLY CHAMBERS THAT ARE APPROVED BY THE SITE DESIGN ENGINEER WILL BE ALLOWED. UPON REQUEST BY THE SITE DESIGN ENGINEER OR OWNER, THE CHAMBER MANUFACTURER SHALL SUBMIT A STRUCTURAL EVALUATION FOR APPROVAL BEFORE DELIVERING CHAMBERS TO THE PROJECT SITE AS FOLLOWS: ·THE STRUCTURAL EVALUATION SHALL BE SEALED BY A REGISTERED PROFESSIONAL ENGINEER. ·THE STRUCTURAL EVALUATION SHALL DEMONSTRATE THAT THE SAFETY FACTORS ARE GREATER THAN OR EQUAL TO 1.95 FOR DEAD LOAD AND 1.75 FOR LIVE LOAD, THE MINIMUM REQUIRED BY ASTM F2787 AND BY SECTIONS 3 AND 12.12 OF THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS FOR THERMOPLASTIC PIPE. ·THE TEST DERIVED CREEP MODULUS AS SPECIFIED IN ASTM F2418 SHALL BE USED FOR PERMANENT DEAD LOAD DESIGN EXCEPT THAT IT SHALL BE THE 75-YEAR MODULUS USED FOR DESIGN. 9.CHAMBERS AND END CAPS SHALL BE PRODUCED AT AN ISO 9001 CERTIFIED MANUFACTURING FACILITY. IMPORTANT - NOTES FOR THE BIDDING AND INSTALLATION OF MC-3500 CHAMBER SYSTEM 1.STORMTECH MC-3500 CHAMBERS SHALL NOT BE INSTALLED UNTIL THE MANUFACTURER'S REPRESENTATIVE HAS COMPLETED A PRE-CONSTRUCTION MEETING WITH THE INSTALLERS. 2.STORMTECH MC-3500 CHAMBERS SHALL BE INSTALLED IN ACCORDANCE WITH THE "STORMTECH MC-3500/MC-4500 CONSTRUCTION GUIDE". 3.CHAMBERS ARE NOT TO BE BACKFILLED WITH A DOZER OR AN EXCAVATOR SITUATED OVER THE CHAMBERS. STORMTECH RECOMMENDS 3 BACKFILL METHODS: ·STONESHOOTER LOCATED OFF THE CHAMBER BED. ·BACKFILL AS ROWS ARE BUILT USING AN EXCAVATOR ON THE FOUNDATION STONE OR SUBGRADE. ·BACKFILL FROM OUTSIDE THE EXCAVATION USING A LONG BOOM HOE OR EXCAVATOR. 4.THE FOUNDATION STONE SHALL BE LEVELED AND COMPACTED PRIOR TO PLACING CHAMBERS. 5.JOINTS BETWEEN CHAMBERS SHALL BE PROPERLY SEATED PRIOR TO PLACING STONE. 6.MAINTAIN MINIMUM - SPACING BETWEEN THE CHAMBER ROWS. 7.INLET AND OUTLET MANIFOLDS MUST BE INSERTED A MINIMUM OF 12" (300 mm) INTO CHAMBER END CAPS. 8.EMBEDMENT STONE SURROUNDING CHAMBERS MUST BE A CLEAN, CRUSHED, ANGULAR STONE MEETING THE AASHTO M43 DESIGNATION OF #3 OR #4. 9.STONE MUST BE PLACED ON THE TOP CENTER OF THE CHAMBER TO ANCHOR THE CHAMBERS IN PLACE AND PRESERVE ROW SPACING. 10.THE CONTRACTOR MUST REPORT ANY DISCREPANCIES WITH CHAMBER FOUNDATION MATERIALS BEARING CAPACITIES TO THE SITE DESIGN ENGINEER. 11.ADS RECOMMENDS THE USE OF "FLEXSTORM CATCH IT" INSERTS DURING CONSTRUCTION FOR ALL INLETS TO PROTECT THE SUBSURFACE STORMWATER MANAGEMENT SYSTEM FROM CONSTRUCTION SITE RUNOFF. NOTES FOR CONSTRUCTION EQUIPMENT 1.STORMTECH MC-3500 CHAMBERS SHALL BE INSTALLED IN ACCORDANCE WITH THE "STORMTECH MC-3500/MC-4500 CONSTRUCTION GUIDE". 2.THE USE OF EQUIPMENT OVER MC-3500 CHAMBERS IS LIMITED: ·NO EQUIPMENT IS ALLOWED ON BARE CHAMBERS. ·NO RUBBER TIRED LOADER, DUMP TRUCK, OR EXCAVATORS ARE ALLOWED UNTIL PROPER FILL DEPTHS ARE REACHED IN ACCORDANCE WITH THE "STORMTECH MC-3500/MC-4500 CONSTRUCTION GUIDE". ·WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT CAN BE FOUND IN THE "STORMTECH MC-3500/MC-4500 CONSTRUCTION GUIDE". 3.FULL 36" (900 mm) OF STABILIZED COVER MATERIALS OVER THE CHAMBERS IS REQUIRED FOR DUMP TRUCK TRAVEL OR DUMPING. USE OF A DOZER TO PUSH EMBEDMENT STONE BETWEEN THE ROWS OF CHAMBERS MAY CAUSE DAMAGE TO CHAMBERS AND IS NOT AN ACCEPTABLE BACKFILL METHOD. ANY CHAMBERS DAMAGED BY USING THE "DUMP AND PUSH" METHOD ARE NOT COVERED UNDER THE STORMTECH STANDARD WARRANTY. CONTACT STORMTECH AT 1-888-892-2694 WITH ANY QUESTIONS ON INSTALLATION REQUIREMENTS OR WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT. 6" (150 mm) FOR STORMTECH INSTALLATION INSTRUCTIONS VISIT OUR APP SiteAssist Appendix B - Figure 22 DATEDRWNCHKDDESCRIPTION08/24/22SDMREVISED PER ENG'S NEW PLANS, WAS MC-350008/25/22SDMREVISED PER EPM NOTES08/26/22SDMREVISED PER EPM NOTES08/30/22SDMREVISED PER SALES NOTES08/31/22SDMCOMBINED ALL OPTIONS, FIXED LAYOUT TABLES10/10/22SDMCREATED OPTION 7 PER EPM NOTES11-03-22TSGRWDSET ELEVATIONS / UPDATED VR / NW AND SW11-04-22TSGRWDINCREASE VR / EXPAND SE AND TRIANGLE2/1/23BMWCJDNEW LAYOUT AREA AND VOLUME02/09/23CTSCTSPER EPM / ENGINEER EMAIL AND NOTES0050'100'SHEET OFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THEULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 430262 807/13/22S303454SDMXXX HQ & TRAINING CENTERSEATTLE SOUNDERS FCRENTON, WANOTES ·MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECHNICAL NOTE 6.32 FOR MANIFOLD SIZING GUIDANCE. ·DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BE NECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLD COMPONENTS IN THE FIELD. ·THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARING CAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR DETERMINING THE SUITABILITY OF THE SOIL AND PROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASED ONCE THIS INFORMATION IS PROVIDED. ·NOT FOR CONSTRUCTION: THIS LAYOUT IS FOR DIMENSIONAL PURPOSES ONLY TO PROVE CONCEPT & THE REQUIRED STORAGE VOLUME CAN BE ACHIEVED ON SITE StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®PROPOSED LAYOUT: NORTH SYSTEM 1,666 STORMTECH MC-3500 CHAMBERS 68 STORMTECH MC-3500 END CAPS 12 STONE ABOVE (in) 9 STONE BELOW (in) 40 % STONE VOID 292,010 INSTALLED SYSTEM VOLUME (CF) BETWEEN ELEVATION 20.0 & 14.7 (PERIMETER STONE INCLUDED) 85578 SYSTEM AREA (ft²) 1196 SYSTEM PERIMETER (ft) PROPOSED ELEVATIONS: NORTH SYSTEM 27.00 MAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED) 21.00 MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC) 20.50 MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC) 20.50 MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT) 20.50 MINIMUM ALLOWABLE GRADE (TOP OF RIGID PAVEMENT) 20.00 TOP OF STONE 19.00 TOP OF MC-3500 CHAMBER 17.17 24" TOP MANIFOLD INVERT 15.42 24" ISOLATOR ROW PLUS CONNECTION INVERT 15.25 BOTTOM OF MC-3500 CHAMBER 14.50 BOTTOM OF STONE StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®PROPOSED LAYOUT: COMBINED 3,332 STORMTECH MC-3500 CHAMBERS 136 STORMTECH MC-3500 END CAPS 12 STONE ABOVE (in) 9 STONE BELOW (in) 40 % STONE VOID 584,020 INSTALLED SYSTEM VOLUME (CF) BETWEEN ELEVATION 20.0 & 14.7 (PERIMETER STONE INCLUDED) 171156 SYSTEM AREA (ft²) 2,392 SYSTEM PERIMETER (ft) PLACE MINIMUM 17.5' OF ADSPLUS175 WOVEN GEOTEXTILE OVER BEDDING STONE AND UNDERNEATH CHAMBER FEET FOR SCOUR PROTECTION AT ALL CHAMBER INLET ROWS 24" PARTIAL CUT END CAP PART# MC3500IEPP24TC OR MC3500IEPP24TW TYP OF ALL MC-3500 24" TOP CONNECTIONS 24" PARTIAL CUT END CAP, PART# MC3500IEPP24BC OR MC3500IEPP24BW TYP OF ALL MC-3500 24" BOTTOM CONNECTIONS AND ISOLATOR PLUS ROWS INSTALL FLAMP ON 24" ACCESS PIPE PART# MC350024RAMP 24" X 24" ADS N-12 TOP MANIFOLD INVERT 23.05" ABOVE CHAMBER BASE (SEE NOTES) INSPECTION PORT PROPOSED STRUCTURE W/ELEVATED BYPASS MANIFOLD MAXIMUM INLET FLOW 30.1 CFS MAXIMUM OUTLET FLOW 7.0 CFS (DESIGN BY ENGINEER / PROVIDED BY OTHERS) ISOLATOR ROW PLUS (SEE DETAIL)StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®PROPOSED MAINTENANCE STRUCTURE (DESIGN BY ENGINEER / PROVIDED BY OTHERS) 236.67' 234.67'361.60'354.94' DATEDRWNCHKDDESCRIPTION08/24/22SDMREVISED PER ENG'S NEW PLANS, WAS MC-350008/25/22SDMREVISED PER EPM NOTES08/26/22SDMREVISED PER EPM NOTES08/30/22SDMREVISED PER SALES NOTES08/31/22SDMCOMBINED ALL OPTIONS, FIXED LAYOUT TABLES10/10/22SDMCREATED OPTION 7 PER EPM NOTES11-03-22TSGRWDSET ELEVATIONS / UPDATED VR / NW AND SW11-04-22TSGRWDINCREASE VR / EXPAND SE AND TRIANGLE2/1/23BMWCJDNEW LAYOUT AREA AND VOLUME02/09/23CTSCTSPER EPM / ENGINEER EMAIL AND NOTES0050'100'SHEET OFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THEULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 430263 807/13/22S303454SDMXXX HQ & TRAINING CENTERSEATTLE SOUNDERS FCRENTON, WAStormTechChamber System888-892-2694 | WWW.STORMTECH.COM®StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®StormTechChamber System888-892-2694 | WWW.STORMTECH.COM®NOTES ·MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECHNICAL NOTE 6.32 FOR MANIFOLD SIZING GUIDANCE. ·DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BE NECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLD COMPONENTS IN THE FIELD. ·THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARING CAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR DETERMINING THE SUITABILITY OF THE SOIL AND PROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASED ONCE THIS INFORMATION IS PROVIDED. ·NOT FOR CONSTRUCTION: THIS LAYOUT IS FOR DIMENSIONAL PURPOSES ONLY TO PROVE CONCEPT & THE REQUIRED STORAGE VOLUME CAN BE ACHIEVED ON SITE PROPOSED LAYOUT: SOUTH SYSTEM 1,666 STORMTECH MC-3500 CHAMBERS 68 STORMTECH MC-3500 END CAPS 12 STONE ABOVE (in) 9 STONE BELOW (in) 40 % STONE VOID 292,010 INSTALLED SYSTEM VOLUME (CF) BETWEEN ELEVATION 20.0 & 14.7 (PERIMETER STONE INCLUDED) 85578 SYSTEM AREA (ft²) 1196 SYSTEM PERIMETER (ft) PROPOSED ELEVATIONS: SOUTH SYSTEM 27.00 MAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED) 21.00 MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC) 20.50 MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC) 20.50 MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT) 20.50 MINIMUM ALLOWABLE GRADE (TOP OF RIGID PAVEMENT) 20.00 TOP OF STONE 19.00 TOP OF MC-3500 CHAMBER 17.17 24" TOP MANIFOLD INVERT 15.42 24" ISOLATOR ROW PLUS CONNECTION INVERT 15.25 BOTTOM OF MC-3500 CHAMBER 14.50 BOTTOM OF STONE PROPOSED LAYOUT: COMBINED 3,332 STORMTECH MC-3500 CHAMBERS 136 STORMTECH MC-3500 END CAPS 12 STONE ABOVE (in) 9 STONE BELOW (in) 40 % STONE VOID 584,020 INSTALLED SYSTEM VOLUME (CF) BETWEEN ELEVATION 20.0 & 14.7 (PERIMETER STONE INCLUDED) 171156 SYSTEM AREA (ft²) 2,392 SYSTEM PERIMETER (ft) 361.60' 354.94'236.67'234.67'PLACE MINIMUM 17.5' OF ADSPLUS175 WOVEN GEOTEXTILE OVER BEDDING STONE AND UNDERNEATH CHAMBER FEET FOR SCOUR PROTECTION AT ALL CHAMBER INLET ROWS 24" PARTIAL CUT END CAP PART# MC3500IEPP24TC OR MC3500IEPP24TW TYP OF ALL MC-3500 24" TOP CONNECTIONS 24" PARTIAL CUT END CAP, PART# MC3500IEPP24BC OR MC3500IEPP24BW TYP OF ALL MC-3500 24" BOTTOM CONNECTIONS AND ISOLATOR PLUS ROWS INSTALL FLAMP ON 24" ACCESS PIPE PART# MC350024RAMP 24" X 24" ADS N-12 TOP MANIFOLD INVERT 23.05" ABOVE CHAMBER BASE (SEE NOTES) PROPOSED STRUCTURE W/ELEVATED BYPASS MANIFOLD MAXIMUM INLET FLOW 30.1 CFS MAXIMUM OUTLET FLOW 7.0 CFS (DESIGN BY ENGINEER / PROVIDED BY OTHERS) ISOLATOR ROW PLUS (SEE DETAIL) INSPECTION PORT PROPOSED MAINTENANCE STRUCTURE (DESIGN BY ENGINEER / PROVIDED BY OTHERS) SHEET OFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THEULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 430266 807/13/22S303454SDMXXX HQ & TRAINING CENTERSEATTLE SOUNDERS FCRENTON, WADATEDRWNCHKDDESCRIPTION08/24/22SDMREVISED PER ENG'S NEW PLANS, WAS MC-350008/25/22SDMREVISED PER EPM NOTES08/26/22SDMREVISED PER EPM NOTES08/30/22SDMREVISED PER SALES NOTES08/31/22SDMCOMBINED ALL OPTIONS, FIXED LAYOUT TABLES10/10/22SDMCREATED OPTION 7 PER EPM NOTES11-03-22TSGRWDSET ELEVATIONS / UPDATED VR / NW AND SW11-04-22TSGRWDINCREASE VR / EXPAND SE AND TRIANGLE2/1/23BMWCJDNEW LAYOUT AREA AND VOLUME02/09/23CTSCTSPER EPM / ENGINEER EMAIL AND NOTESACCEPTABLE FILL MATERIALS: STORMTECH MC-3500 CHAMBER SYSTEMS PLEASE NOTE: 1.THE LISTED AASHTO DESIGNATIONS ARE FOR GRADATIONS ONLY. THE STONE MUST ALSO BE CLEAN, CRUSHED, ANGULAR. FOR EXAMPLE, A SPECIFICATION FOR #4 STONE WOULD STATE: "CLEAN, CRUSHED, ANGULAR NO. 4 (AASHTO M43) STONE". 2.STORMTECH COMPACTION REQUIREMENTS ARE MET FOR 'A' LOCATION MATERIALS WHEN PLACED AND COMPACTED IN 9" (230 mm) (MAX) LIFTS USING TWO FULL COVERAGES WITH A VIBRATORY COMPACTOR. 3.WHERE INFILTRATION SURFACES MAY BE COMPROMISED BY COMPACTION, FOR STANDARD DESIGN LOAD CONDITIONS, A FLAT SURFACE MAY BE ACHIEVED BY RAKING OR DRAGGING WITHOUT COMPACTION EQUIPMENT. FOR SPECIAL LOAD DESIGNS, CONTACT STORMTECH FOR COMPACTION REQUIREMENTS. 4.ONCE LAYER 'C' IS PLACED, ANY SOIL/MATERIAL CAN BE PLACED IN LAYER 'D' UP TO THE FINISHED GRADE. MOST PAVEMENT SUBBASE SOILS CAN BE USED TO REPLACE THE MATERIAL REQUIREMENTS OF LAYER 'C' OR 'D' AT THE SITE DESIGN ENGINEER'S DISCRETION. NOTES: 1.CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED WALL STORMWATER COLLECTION CHAMBERS" CHAMBER CLASSIFICATION 45x76 DESIGNATION SS. 2.MC-3500 CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH ASTM F2787 "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". 3.THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR ASSESSING THE BEARING RESISTANCE (ALLOWABLE BEARING CAPACITY) OF THE SUBGRADE SOILS AND THE DEPTH OF FOUNDATION STONE WITH CONSIDERATION FOR THE RANGE OF EXPECTED SOIL MOISTURE CONDITIONS. 4.PERIMETER STONE MUST BE EXTENDED HORIZONTALLY TO THE EXCAVATION WALL FOR BOTH VERTICAL AND SLOPED EXCAVATION WALLS. 5.REQUIREMENTS FOR HANDLING AND INSTALLATION: ·TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING STACKING LUGS. ·TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS THAN 3”. ·TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT AS DEFINED IN SECTION 6.2.8 OF ASTM F2418 SHALL BE GREATER THAN OR EQUAL TO 500 LBS/FT/%. AND b) TO RESIST CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73° F / 23° C), CHAMBERS SHALL BE PRODUCED FROM REFLECTIVE GOLD OR YELLOW COLORS. MATERIAL LOCATION DESCRIPTION AASHTO MATERIAL CLASSIFICATIONS COMPACTION / DENSITY REQUIREMENT D FINAL FILL: FILL MATERIAL FOR LAYER 'D' STARTS FROM THE TOP OF THE 'C' LAYER TO THE BOTTOM OF FLEXIBLE PAVEMENT OR UNPAVED FINISHED GRADE ABOVE. NOTE THAT PAVEMENT SUBBASE MAY BE PART OF THE 'D' LAYER ANY SOIL/ROCK MATERIALS, NATIVE SOILS, OR PER ENGINEER'S PLANS. CHECK PLANS FOR PAVEMENT SUBGRADE REQUIREMENTS.N/A PREPARE PER SITE DESIGN ENGINEER'S PLANS. PAVED INSTALLATIONS MAY HAVE STRINGENT MATERIAL AND PREPARATION REQUIREMENTS. C INITIAL FILL: FILL MATERIAL FOR LAYER 'C' STARTS FROM THE TOP OF THE EMBEDMENT STONE ('B' LAYER) TO 24" (600 mm) ABOVE THE TOP OF THE CHAMBER. NOTE THAT PAVEMENT SUBBASE MAY BE A PART OF THE 'C' LAYER. GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35% FINES OR PROCESSED AGGREGATE. MOST PAVEMENT SUBBASE MATERIALS CAN BE USED IN LIEU OF THIS LAYER. AASHTO M145¹ A-1, A-2-4, A-3 OR AASHTO M43¹ 3, 357, 4, 467, 5, 56, 57, 6, 67, 68, 7, 78, 8, 89, 9, 10 BEGIN COMPACTIONS AFTER 24" (600 mm) OF MATERIAL OVER THE CHAMBERS IS REACHED. COMPACT ADDITIONAL LAYERS IN 12" (300 mm) MAX LIFTS TO A MIN. 95% PROCTOR DENSITY FOR WELL GRADED MATERIAL AND 95% RELATIVE DENSITY FOR PROCESSED AGGREGATE MATERIALS. B EMBEDMENT STONE: FILL SURROUNDING THE CHAMBERS FROM THE FOUNDATION STONE ('A' LAYER) TO THE 'C' LAYER ABOVE. CLEAN, CRUSHED, ANGULAR STONE AASHTO M43¹ 3, 4 A FOUNDATION STONE: FILL BELOW CHAMBERS FROM THE SUBGRADE UP TO THE FOOT (BOTTOM) OF THE CHAMBER.CLEAN, CRUSHED, ANGULAR STONE AASHTO M43¹ 3, 4 PLATE COMPACT OR ROLL TO ACHIEVE A FLAT SURFACE.2,3 NO COMPACTION REQUIRED. 8' (2.4 m) MAX 12" (300 mm) MIN77" (1956 mm) 12" (300 mm) MIN 6" (150 mm) MIN 6" (150 mm) MIN PERIMETER STONE (SEE NOTE 4) EXCAVATION WALL (CAN BE SLOPED OR VERTICAL) MC-3500 END CAP SUBGRADE SOILS (SEE NOTE 3) DEPTH OF STONE TO BE DETERMINED BY SITE DESIGN ENGINEER 9" (230 mm) MIN ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE ALL AROUND CLEAN, CRUSHED, ANGULAR STONE IN A & B LAYERS D C B A *TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR, INCREASE COVER TO 24" (600 mm). 45" (1143 mm) 18" (450 mm) MIN* **THIS CROSS SECTION DETAIL REPRESENTS MINIMUM REQUIREMENTS FOR INSTALLATION. PLEASE SEE THE LAYOUT SHEET(S) FOR PROJECT SPECIFIC REQUIREMENTS.StormTechChamber System888-892-2694 | WWW.STORMTECH.COM® SHEET OFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THEULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 430267 807/13/22S303454SDMXXX HQ & TRAINING CENTERSEATTLE SOUNDERS FCRENTON, WADATEDRWNCHKDDESCRIPTION08/24/22SDMREVISED PER ENG'S NEW PLANS, WAS MC-350008/25/22SDMREVISED PER EPM NOTES08/26/22SDMREVISED PER EPM NOTES08/30/22SDMREVISED PER SALES NOTES08/31/22SDMCOMBINED ALL OPTIONS, FIXED LAYOUT TABLES10/10/22SDMCREATED OPTION 7 PER EPM NOTES11-03-22TSGRWDSET ELEVATIONS / UPDATED VR / NW AND SW11-04-22TSGRWDINCREASE VR / EXPAND SE AND TRIANGLE2/1/23BMWCJDNEW LAYOUT AREA AND VOLUME02/09/23CTSCTSPER EPM / ENGINEER EMAIL AND NOTESINSPECTION & MAINTENANCE STEP 1)INSPECT ISOLATOR ROW PLUS FOR SEDIMENT A.INSPECTION PORTS (IF PRESENT) A.1.REMOVE/OPEN LID ON NYLOPLAST INLINE DRAIN A.2.REMOVE AND CLEAN FLEXSTORM FILTER IF INSTALLED A.3.USING A FLASHLIGHT AND STADIA ROD, MEASURE DEPTH OF SEDIMENT AND RECORD ON MAINTENANCE LOG A.4.LOWER A CAMERA INTO ISOLATOR ROW PLUS FOR VISUAL INSPECTION OF SEDIMENT LEVELS (OPTIONAL) A.5.IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3. B.ALL ISOLATOR PLUS ROWS B.1.REMOVE COVER FROM STRUCTURE AT UPSTREAM END OF ISOLATOR ROW PLUS B.2.USING A FLASHLIGHT, INSPECT DOWN THE ISOLATOR ROW PLUS THROUGH OUTLET PIPE i)MIRRORS ON POLES OR CAMERAS MAY BE USED TO AVOID A CONFINED SPACE ENTRY ii)FOLLOW OSHA REGULATIONS FOR CONFINED SPACE ENTRY IF ENTERING MANHOLE B.3.IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3. STEP 2)CLEAN OUT ISOLATOR ROW PLUS USING THE JETVAC PROCESS A.A FIXED CULVERT CLEANING NOZZLE WITH REAR FACING SPREAD OF 45" (1.1 m) OR MORE IS PREFERRED B.APPLY MULTIPLE PASSES OF JETVAC UNTIL BACKFLUSH WATER IS CLEAN C.VACUUM STRUCTURE SUMP AS REQUIRED STEP 3)REPLACE ALL COVERS, GRATES, FILTERS, AND LIDS; RECORD OBSERVATIONS AND ACTIONS. STEP 4)INSPECT AND CLEAN BASINS AND MANHOLES UPSTREAM OF THE STORMTECH SYSTEM. NOTES 1.INSPECT EVERY 6 MONTHS DURING THE FIRST YEAR OF OPERATION. ADJUST THE INSPECTION INTERVAL BASED ON PREVIOUS OBSERVATIONS OF SEDIMENT ACCUMULATION AND HIGH WATER ELEVATIONS. 2.CONDUCT JETTING AND VACTORING ANNUALLY OR WHEN INSPECTION SHOWS THAT MAINTENANCE IS NECESSARY. SUMP DEPTH TBD BY SITE DESIGN ENGINEER (24" [600 mm] MIN RECOMMENDED) 24" (600 mm) HDPE ACCESS PIPE REQUIRED USE FACTORY PARTIAL CUT END CAP PART #: MC3500IEPP24BC OR MC3500IEPP24BW ONE LAYER OF ADSPLUS175 WOVEN GEOTEXTILE BETWEEN FOUNDATION STONE AND CHAMBERS 8.25' (2.51 m) MIN WIDE CONTINUOUS FABRIC WITHOUT SEAMS CATCH BASIN OR MANHOLE COVER PIPE CONNECTION TO END CAP WITH ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE MC-3500 CHAMBER MC-3500 END CAP MC-3500 ISOLATOR ROW PLUS DETAIL NTS OPTIONAL INSPECTION PORT STORMTECH HIGHLY RECOMMENDS FLEXSTORM INSERTS IN ANY UPSTREAM STRUCTURES WITH OPEN GRATES ELEVATED BYPASS MANIFOLD INSTALL FLAMP ON 24" (600 mm) ACCESS PIPE PART #: MC350024RAMP NOTE: INSPECTION PORTS MAY BE CONNECTED THROUGH ANY CHAMBER CORRUGATION VALLEY. STORMTECH CHAMBER CONCRETE COLLAR PAVEMENT 12" (300 mm) MIN WIDTH CONCRETE SLAB 6" (150 mm) MIN THICKNESS 4" PVC INSPECTION PORT DETAIL (MC SERIES CHAMBER) NTS 8" NYLOPLAST INSPECTION PORT BODY (PART# 2708AG4IPKIT) OR TRAFFIC RATED BOX W/SOLID LOCKING COVER CONCRETE COLLAR NOT REQUIRED FOR UNPAVED APPLICATIONS 4" (100 mm) SDR 35 PIPE 4" (100 mm) INSERTA TEE TO BE CENTERED ON CORRUGATION VALLEY StormTechChamber System888-892-2694 | WWW.STORMTECH.COM® SHEET OFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THEULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 430268 807/13/22S303454SDMXXX HQ & TRAINING CENTERSEATTLE SOUNDERS FCRENTON, WADATEDRWNCHKDDESCRIPTION08/24/22SDMREVISED PER ENG'S NEW PLANS, WAS MC-350008/25/22SDMREVISED PER EPM NOTES08/26/22SDMREVISED PER EPM NOTES08/30/22SDMREVISED PER SALES NOTES08/31/22SDMCOMBINED ALL OPTIONS, FIXED LAYOUT TABLES10/10/22SDMCREATED OPTION 7 PER EPM NOTES11-03-22TSGRWDSET ELEVATIONS / UPDATED VR / NW AND SW11-04-22TSGRWDINCREASE VR / EXPAND SE AND TRIANGLE2/1/23BMWCJDNEW LAYOUT AREA AND VOLUME02/09/23CTSCTSPER EPM / ENGINEER EMAIL AND NOTESStormTechChamber System888-892-2694 | WWW.STORMTECH.COM®PART #STUB B C MC3500IEPP06T 6" (150 mm)33.21" (844 mm)--- MC3500IEPP06B ---0.66" (17 mm) MC3500IEPP08T 8" (200 mm)31.16" (791 mm)--- MC3500IEPP08B ---0.81" (21 mm) MC3500IEPP10T 10" (250 mm)29.04" (738 mm)--- MC3500IEPP10B ---0.93" (24 mm) MC3500IEPP12T 12" (300 mm)26.36" (670 mm)--- MC3500IEPP12B ---1.35" (34 mm) MC3500IEPP15T 15" (375 mm)23.39" (594 mm)--- MC3500IEPP15B ---1.50" (38 mm) MC3500IEPP18TC 18" (450 mm) 20.03" (509 mm)---MC3500IEPP18TW MC3500IEPP18BC ---1.77" (45 mm)MC3500IEPP18BW MC3500IEPP24TC 24" (600 mm) 14.48" (368 mm)---MC3500IEPP24TW MC3500IEPP24BC ---2.06" (52 mm)MC3500IEPP24BW MC3500IEPP30BC 30" (750 mm)---2.75" (70 mm) NOMINAL CHAMBER SPECIFICATIONS SIZE (W X H X INSTALLED LENGTH)77.0" X 45.0" X 86.0" (1956 mm X 1143 mm X 2184 mm) CHAMBER STORAGE 109.9 CUBIC FEET (3.11 m³) MINIMUM INSTALLED STORAGE*175.0 CUBIC FEET (4.96 m³) WEIGHT 134 lbs.(60.8 kg) NOMINAL END CAP SPECIFICATIONS SIZE (W X H X INSTALLED LENGTH)75.0" X 45.0" X 22.2" (1905 mm X 1143 mm X 564 mm) END CAP STORAGE 14.9 CUBIC FEET (0.42 m³) MINIMUM INSTALLED STORAGE*45.1 CUBIC FEET (1.28 m³) WEIGHT 49 lbs.(22.2 kg) *ASSUMES 12" (305 mm) STONE ABOVE, 9" (229 mm) STONE FOUNDATION, 6" (152 mm) STONE BETWEEN CHAMBERS, 6" (152 mm) STONE PERIMETER IN FRONT OF END CAPS AND 40% STONE POROSITY. MC-3500 TECHNICAL SPECIFICATION NTS 90.0" (2286 mm) ACTUAL LENGTH 86.0" (2184 mm) INSTALLED BUILD ROW IN THIS DIRECTION NOTE: ALL DIMENSIONS ARE NOMINAL LOWER JOINT CORRUGATION WEB CREST CREST STIFFENING RIB VALLEY STIFFENING RIB B C 75.0" (1905 mm) 45.0" (1143 mm) 25.7" (653 mm) FOOT 77.0" (1956 mm) 45.0" (1143 mm) PARTIAL CUT HOLES AT BOTTOM OF END CAP FOR PART NUMBERS ENDING WITH "B" PARTIAL CUT HOLES AT TOP OF END CAP FOR PART NUMBERS ENDING WITH "T" END CAPS WITH A PREFABRICATED WELDED STUB END WITH "W" END CAPS WITH A WELDED CROWN PLATE END WITH "C" UPPER JOINT CORRUGATION 22.2" (564 mm) INSTALLED CUSTOM PARTIAL CUT INVERTS ARE AVAILABLE UPON REQUEST. INVENTORIED MANIFOLDS INCLUDE 12-24" (300-600 mm) SIZE ON SIZE AND 15-48" (375-1200 mm) ECCENTRIC MANIFOLDS. CUSTOM INVERT LOCATIONS ON THE MC-3500 END CAP CUT IN THE FIELD ARE NOT RECOMMENDED FOR PIPE SIZES GREATER THAN 10" (250 mm). THE INVERT LOCATION IN COLUMN 'B' ARE THE HIGHEST POSSIBLE FOR THE PIPE SIZE. MC-SERIES END CAP INSERTION DETAIL NTS NOTE: MANIFOLD STUB MUST BE LAID HORIZONTAL FOR A PROPER FIT IN END CAP OPENING. 12" (300 mm) MIN SEPARATION 12" (300 mm) MIN INSERTION MANIFOLD HEADER MANIFOLD STUB STORMTECH END CAP 12" (300 mm) MIN SEPARATION 12" (300 mm) MIN INSERTION MANIFOLD HEADER MANIFOLD STUB SOUTH SYSTEM NORTH SYSTEM Project: Chamber Model - MC-3500 Units -Imperial Number of Chambers -1666 Number of End Caps -68 Voids in the stone (porosity) - 40 % Base of Stone Elevation - 14.50 ft Amount of Stone Above Chambers - 12 in Amount of Stone Below Chambers - 9 in Area of system -85578 sf Min. Area - Height of System Incremental Single Chamber Incremental Single End Cap Incremental Chambers Incremental End Cap Incremental Stone Incremental Ch, EC and Stone Cumulative System Elevation (inches)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(feet) 66 0.00 0.00 0.00 0.00 2852.60 2852.60 298785.00 20.00 65 0.00 0.00 0.00 0.00 2852.60 2852.60 295932.40 19.92 64 0.00 0.00 0.00 0.00 2852.60 2852.60 293079.80 19.83 63 0.00 0.00 0.00 0.00 2852.60 2852.60 290227.20 19.75 62 0.00 0.00 0.00 0.00 2852.60 2852.60 287374.60 19.67 61 0.00 0.00 0.00 0.00 2852.60 2852.60 284522.00 19.58 60 0.00 0.00 0.00 0.00 2852.60 2852.60 281669.40 19.50 59 0.00 0.00 0.00 0.00 2852.60 2852.60 278816.80 19.42 58 0.00 0.00 0.00 0.00 2852.60 2852.60 275964.20 19.33 57 0.00 0.00 0.00 0.00 2852.60 2852.60 273111.60 19.25 56 0.00 0.00 0.00 0.00 2852.60 2852.60 270259.00 19.17 55 0.00 0.00 0.00 0.00 2852.60 2852.60 267406.40 19.08 54 0.06 0.00 96.77 0.00 2813.89 2910.66 264553.80 19.00 53 0.19 0.02 323.37 1.63 2722.60 3047.60 261643.14 18.92 52 0.29 0.04 489.74 2.56 2655.68 3147.98 258595.54 18.83 51 0.40 0.05 672.47 3.51 2582.21 3258.19 255447.56 18.75 50 0.69 0.07 1144.84 4.60 2392.82 3542.26 252189.38 18.67 49 1.03 0.09 1713.14 6.00 2164.94 3884.08 248647.11 18.58 48 1.25 0.11 2081.71 7.29 2017.00 4106.00 244763.03 18.50 47 1.42 0.13 2369.43 8.59 1901.39 4279.41 240657.03 18.42 46 1.57 0.14 2620.84 9.82 1800.34 4431.00 236377.61 18.33 45 1.71 0.16 2844.12 11.07 1710.52 4565.71 231946.62 18.25 44 1.83 0.18 3046.28 12.36 1629.15 4687.78 227380.90 18.17 43 1.94 0.20 3228.32 13.64 1555.82 4797.78 222693.12 18.08 42 2.04 0.22 3400.01 14.84 1486.66 4901.51 217895.35 18.00 41 2.13 0.23 3556.39 15.98 1423.65 4996.02 212993.84 17.92 40 2.22 0.25 3705.55 17.04 1363.56 5086.15 207997.82 17.83 39 2.31 0.27 3843.11 18.06 1308.13 5169.30 202911.66 17.75 38 2.38 0.28 3973.03 19.04 1255.77 5247.84 197742.36 17.67 37 2.46 0.29 4096.85 19.99 1205.86 5322.70 192494.52 17.58 36 2.53 0.31 4211.93 20.93 1159.45 5392.32 187171.82 17.50 35 2.59 0.32 4321.18 21.84 1115.39 5458.41 181779.49 17.42 34 2.66 0.33 4424.99 22.74 1073.51 5521.24 176321.08 17.33 33 2.72 0.35 4523.36 23.60 1033.82 5580.78 170799.84 17.25 32 2.77 0.36 4616.97 24.48 996.02 5637.47 165219.07 17.17 31 2.82 0.37 4705.87 25.32 960.13 5691.31 159581.60 17.08 30 2.88 0.38 4790.51 26.13 925.94 5742.59 153890.29 17.00 29 2.92 0.40 4871.61 26.93 893.18 5791.73 148147.70 16.92 28 2.97 0.41 4947.83 27.72 862.38 5837.93 142355.97 16.83 27 3.01 0.42 5018.74 28.47 833.71 5880.93 136518.05 16.75 26 3.05 0.43 5086.73 29.22 806.22 5922.17 130637.12 16.67 25 3.09 0.44 5155.06 29.95 778.60 5963.61 124714.95 16.58 24 3.13 0.45 5215.51 30.66 754.13 6000.30 118751.35 16.50 23 3.17 0.46 5273.99 31.34 730.47 6035.80 112751.05 16.42 22 3.20 0.47 5330.29 32.00 707.68 6069.98 106715.25 16.33 21 3.23 0.48 5383.04 32.65 686.33 6102.01 100645.27 16.25 20 3.26 0.49 5433.51 33.27 665.89 6132.66 94543.26 16.17 19 3.29 0.50 5481.57 33.86 646.43 6161.86 88410.60 16.08 18 3.32 0.51 5527.73 34.44 627.73 6189.90 82248.74 16.00 17 3.34 0.51 5571.31 34.99 610.08 6216.38 76058.84 15.92 16 3.37 0.52 5612.12 35.51 593.55 6241.18 69842.46 15.83 15 3.39 0.53 5651.91 36.01 577.43 6265.35 63601.29 15.75 14 3.41 0.54 5688.62 36.49 562.56 6287.67 57335.94 15.67 13 3.44 0.54 5726.07 36.94 547.40 6310.40 51048.27 15.58 12 3.46 0.55 5760.55 37.36 533.44 6331.34 44737.86 15.50 11 3.48 0.56 5795.50 37.76 519.30 6352.56 38406.52 15.42 10 3.51 0.59 5839.48 40.45 500.62 6380.56 32053.96 15.33 9 0.00 0.00 0.00 0.00 2852.60 2852.60 25673.40 15.25 8 0.00 0.00 0.00 0.00 2852.60 2852.60 22820.80 15.17 7 0.00 0.00 0.00 0.00 2852.60 2852.60 19968.20 15.08 6 0.00 0.00 0.00 0.00 2852.60 2852.60 17115.60 15.00 5 0.00 0.00 0.00 0.00 2852.60 2852.60 14263.00 14.92 4 0.00 0.00 0.00 0.00 2852.60 2852.60 11410.40 14.83 3 0.00 0.00 0.00 0.00 2852.60 2852.60 8557.80 14.75 2 0.00 0.00 0.00 0.00 2852.60 2852.60 5705.20 14.67 1 0.00 0.00 0.00 0.00 2852.60 2852.60 2852.60 14.58 Seattle Sounders FC - North Bed 83688 sf min. area StormTech MC-3500 Cumulative Storage Volumes Project: Chamber Model - MC-3500 Units -Imperial Number of Chambers -1666 Number of End Caps -68 Voids in the stone (porosity) - 40 % Base of Stone Elevation - 14.50 ft Amount of Stone Above Chambers - 12 in Amount of Stone Below Chambers - 9 in Area of system -85578 sf Min. Area - Height of System Incremental Single Chamber Incremental Single End Cap Incremental Chambers Incremental End Cap Incremental Stone Incremental Ch, EC and Stone Cumulative System Elevation (inches)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(feet) 66 0.00 0.00 0.00 0.00 2852.60 2852.60 298785.00 20.00 65 0.00 0.00 0.00 0.00 2852.60 2852.60 295932.40 19.92 64 0.00 0.00 0.00 0.00 2852.60 2852.60 293079.80 19.83 63 0.00 0.00 0.00 0.00 2852.60 2852.60 290227.20 19.75 62 0.00 0.00 0.00 0.00 2852.60 2852.60 287374.60 19.67 61 0.00 0.00 0.00 0.00 2852.60 2852.60 284522.00 19.58 60 0.00 0.00 0.00 0.00 2852.60 2852.60 281669.40 19.50 59 0.00 0.00 0.00 0.00 2852.60 2852.60 278816.80 19.42 58 0.00 0.00 0.00 0.00 2852.60 2852.60 275964.20 19.33 57 0.00 0.00 0.00 0.00 2852.60 2852.60 273111.60 19.25 56 0.00 0.00 0.00 0.00 2852.60 2852.60 270259.00 19.17 55 0.00 0.00 0.00 0.00 2852.60 2852.60 267406.40 19.08 54 0.06 0.00 96.77 0.00 2813.89 2910.66 264553.80 19.00 53 0.19 0.02 323.37 1.63 2722.60 3047.60 261643.14 18.92 52 0.29 0.04 489.74 2.56 2655.68 3147.98 258595.54 18.83 51 0.40 0.05 672.47 3.51 2582.21 3258.19 255447.56 18.75 50 0.69 0.07 1144.84 4.60 2392.82 3542.26 252189.38 18.67 49 1.03 0.09 1713.14 6.00 2164.94 3884.08 248647.11 18.58 48 1.25 0.11 2081.71 7.29 2017.00 4106.00 244763.03 18.50 47 1.42 0.13 2369.43 8.59 1901.39 4279.41 240657.03 18.42 46 1.57 0.14 2620.84 9.82 1800.34 4431.00 236377.61 18.33 45 1.71 0.16 2844.12 11.07 1710.52 4565.71 231946.62 18.25 44 1.83 0.18 3046.28 12.36 1629.15 4687.78 227380.90 18.17 43 1.94 0.20 3228.32 13.64 1555.82 4797.78 222693.12 18.08 42 2.04 0.22 3400.01 14.84 1486.66 4901.51 217895.35 18.00 41 2.13 0.23 3556.39 15.98 1423.65 4996.02 212993.84 17.92 40 2.22 0.25 3705.55 17.04 1363.56 5086.15 207997.82 17.83 39 2.31 0.27 3843.11 18.06 1308.13 5169.30 202911.66 17.75 38 2.38 0.28 3973.03 19.04 1255.77 5247.84 197742.36 17.67 37 2.46 0.29 4096.85 19.99 1205.86 5322.70 192494.52 17.58 36 2.53 0.31 4211.93 20.93 1159.45 5392.32 187171.82 17.50 35 2.59 0.32 4321.18 21.84 1115.39 5458.41 181779.49 17.42 34 2.66 0.33 4424.99 22.74 1073.51 5521.24 176321.08 17.33 33 2.72 0.35 4523.36 23.60 1033.82 5580.78 170799.84 17.25 32 2.77 0.36 4616.97 24.48 996.02 5637.47 165219.07 17.17 31 2.82 0.37 4705.87 25.32 960.13 5691.31 159581.60 17.08 30 2.88 0.38 4790.51 26.13 925.94 5742.59 153890.29 17.00 29 2.92 0.40 4871.61 26.93 893.18 5791.73 148147.70 16.92 28 2.97 0.41 4947.83 27.72 862.38 5837.93 142355.97 16.83 27 3.01 0.42 5018.74 28.47 833.71 5880.93 136518.05 16.75 26 3.05 0.43 5086.73 29.22 806.22 5922.17 130637.12 16.67 25 3.09 0.44 5155.06 29.95 778.60 5963.61 124714.95 16.58 24 3.13 0.45 5215.51 30.66 754.13 6000.30 118751.35 16.50 23 3.17 0.46 5273.99 31.34 730.47 6035.80 112751.05 16.42 22 3.20 0.47 5330.29 32.00 707.68 6069.98 106715.25 16.33 21 3.23 0.48 5383.04 32.65 686.33 6102.01 100645.27 16.25 20 3.26 0.49 5433.51 33.27 665.89 6132.66 94543.26 16.17 19 3.29 0.50 5481.57 33.86 646.43 6161.86 88410.60 16.08 18 3.32 0.51 5527.73 34.44 627.73 6189.90 82248.74 16.00 17 3.34 0.51 5571.31 34.99 610.08 6216.38 76058.84 15.92 16 3.37 0.52 5612.12 35.51 593.55 6241.18 69842.46 15.83 15 3.39 0.53 5651.91 36.01 577.43 6265.35 63601.29 15.75 14 3.41 0.54 5688.62 36.49 562.56 6287.67 57335.94 15.67 13 3.44 0.54 5726.07 36.94 547.40 6310.40 51048.27 15.58 12 3.46 0.55 5760.55 37.36 533.44 6331.34 44737.86 15.50 11 3.48 0.56 5795.50 37.76 519.30 6352.56 38406.52 15.42 10 3.51 0.59 5839.48 40.45 500.62 6380.56 32053.96 15.33 9 0.00 0.00 0.00 0.00 2852.60 2852.60 25673.40 15.25 8 0.00 0.00 0.00 0.00 2852.60 2852.60 22820.80 15.17 7 0.00 0.00 0.00 0.00 2852.60 2852.60 19968.20 15.08 6 0.00 0.00 0.00 0.00 2852.60 2852.60 17115.60 15.00 5 0.00 0.00 0.00 0.00 2852.60 2852.60 14263.00 14.92 4 0.00 0.00 0.00 0.00 2852.60 2852.60 11410.40 14.83 3 0.00 0.00 0.00 0.00 2852.60 2852.60 8557.80 14.75 2 0.00 0.00 0.00 0.00 2852.60 2852.60 5705.20 14.67 1 0.00 0.00 0.00 0.00 2852.60 2852.60 2852.60 14.58 Seattle Sounders FC - South Bed 83688 sf min. area StormTech MC-3500 Cumulative Storage Volumes Acres SF % Cover Total Site per 1998 Drainage Plan 158.00 6882506.86 100% Pond B (measured 2022 survey)2.45 106,812 1.6% Pond B (measured as-designed 1998, Designated Pond "D" in 1998 Report)*2.40 104,446 1.5% *See Page 240 of Sverdrup Drainage Report Pervious + ponds per Sverdrup 1998 55.30 2408877.4 35% Impervious Area 102.70 4473629.5 65% Open Water (2022 Survey) (Pond A, Pond B, Outlet Channels)12.92 562875.0 8.2% Pervious Coverage not including Open Water 42.4 29.2% Imperviuos Area 102.7 70.8% Total Site Area used in 1995 Sverdrup Design (minus Open Water)145.1 Percent Coverage Allowed with no Detention = 70.8% Acres SF Total Acreage 13.15 572,680 Pervious Area - Not Fields 1.51 65,983 Field Area - Natural Turf (50% Pervious)2.70 117,760 Field Area - Natural Turf (50% Impervious)2.70 117,760 Field Area - Synthetic Turf (100% Impervious)4.69 204,178 Impervious Area (Walkways, Drive, Maintenance Yard)0.70 30,500 Existing Concrete Surfaces 0.84 36,500 Total Impervious Area 8.93 388,938 Total Pervious Area 4.22 183,743 % Impervious Area Proposed (Sounders) =67.9% Acres SF Total Acreage 13.15 572,680 Pervious Area 10.67 464,788 Impervious Area (Walkways, Drive, Parking Lot)2.48 107,892 % Impervious Area Coverage Existing (Current Site) = 18.8% Existing Longacres Site, per 1998 Sverdrup Proposal Proposed Sounders Site Existing Sounders Site Figure 23 - Pond B Hydrology Analysis SCALE 1"=150'Drainage Basin MapFIGURE 24OHPxOHPxOHPxOHPxOHPxOHTxOHPxHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPx OHPxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxx SDxSDxSDx SDxSDxSDxSD SDxSDx SDx SDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSx SS WxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx Wx Wx W Wx Wx WxWxWxWxWxWxWxWxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxZONEAEZONE XSDxSDxSDxS D xSDxSDx Wx SDxSDxSDxSDxWxWxXref ..\..\INCOMING\X-Arch FIRST FLOOR PLAN.dwgXref ..\..\INCOMING\X-Maintenance Bldg.dwg 20181921202115152016161617181921 15152016161617182120181921 2018192120212017181921201921201921 2021 2021 161718 202120171819212019212021201921 OHPxOHPxOHPxOHPxOHPxOHTxOHPxHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPx OHPxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxx SDxSDxSDx SDxSDxSDxSD SDxSDx SDx SDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSx SS WxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx Wx Wx W Wx Wx WxWxWxWxWxWxWxWxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxZONEAEZONE XSDxSDxSDxS D xSDxSDx Wx SDxSDxSDxSDxWxWxOHPxOHPxOHPxOHPxOHPxOHTxOHPxHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPx OHPxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxx SDxSDxSDx SDxSDxSDxSD SDxSDx SDx SDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSx SS WxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx Wx Wx W Wx Wx WxWxWxWxWxWxWxWxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxZONEAEZONE XSDxSDxSDxS D xSDxSDx Wx SDxSDxSDxSDxWxWxOHPxOHPxOHPxOHPxOHPxOHTxOHPxHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPx OHPxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxx SDxSDxSDx SDxSDxSDxSD SDxSDx SDx SDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSx SS WxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx Wx Wx W Wx Wx WxWxWxWxWxWxWxWxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxZONEAEZONE XSDxSDxSDxS D xSDxSDx Wx SDxSDxSDxSDxWxWxSUB-01C=0.66TOTAL AREA= 2.28IMPER=1.14PER=1.14SUB-02C=0.66TOTAL AREA= 1.06IMPER=0.53PER=0.53SUB-03C=0.82TOTAL AREA= 1.44IMPER=1.12PER=0.32SUB-07C=0.66TOTAL AREA= 2.38IMPER=1.19PER=1.19SUB-04C=0.66TOTAL AREA= 1.07IMPER=0.535PER=0.535SUB-05C=0.66TOTAL AREA= 1.16IMPER=0.58PER=0.58SUB-06C=0.66TOTAL AREA= 1.21IMPER=0.605PER=0.605SUB-08C=0.90TOTAL AREA= 8.47IMPER=7.71PER=0.76SUB-09C=0.86TOTAL AREA= 1.63IMPER=1.39PER=0.24SUB-10C=0.86TOTAL AREA= 1.63IMPER=1.39PER=0.24 SCALE 1"=200'Longacres Pond Area MapFIGURE 25OHTxOHTxXSDxSDx SDx SDx SDx SDxSDx SDx SDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSD SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDx SDxSDx S D x SDxSDxSDxSDxSDxSDxSDxSDxSDxSDx383,298 sf106,812.3 sf57,177 sf43,376.81 sf71,876 sf30,534.75 sf207,172 sf312,725.5 sf105,812.4 sf233,058.6 sf57,790.44 sf20,819.31 sfSection 4 = 57,790.4sfSection 5 =383,298.5 sfSection 6 = 57 sfPond B =106,812.3sf424,983.9 sfPond A =424,983.9sfPond A = 424,984 sfPond B = 106,812 sfPond C = 20,819 sfOutlet Area=31,363 sfBuilding A = 207,173 sfBuilding B = 71,876 sfHard Surfaces/Roads:Section 1 = 312,726 sfSection 2 = 84,253 sfSection 3 = 233,059 sfSection 4 = 57,790 sfSection 5 = 383,299 sfSection 6 = 57,177 sfSection 7 = 43,377 sfSection 8 = 30,534 sfSection 9 = 11,211 sf5,015,801 sf21,558.75 sf11,210.5 sfSection 9 =11,211 sf31,384 sfOutletChannels =31,363 sfTotal Pond Area = 583,978 sfTotal Building/Roof Area = 279,049 sfTotal Hard Surface Area = 1,213,426 sfTotal Site Area = 6,882,507 sfTotal Pervious Area = 4,806,054 sf XXXOHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHTx OHTx OHPxOHPxOHPxOHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxX OHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPxOHPx OHPx OHPx OHPx OHPx XXXXXXXXXXXXXXXXXXXSSxSSxSSxSSxSSxSSx SSx SSx SSx SSx SSxSSx SS x SS x SS x SS x SSx SSx SSx SSx SSx SSx SSx SDx SDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SSx SSx SSx SSx SSx SSx SSx SSx SSxSSx SSx SSx SSxSSxSSxSSx SDx SSx SSx SSx SSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDx SDxSDx SDx SDx SDx SDxSDxSDxSDx SDx SDx SD x SDx SDx SDx SDx SDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDxSDxSDxSDxSDxSDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxS D x S D xSSxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDx SD x S D x S D x SDxSDx SDxSDxSDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSSxSDxSDxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx Wx Wx Wx Wx Wx W x W x WxWxWxWxWxWxWxWxWxWx Wx Wx Wx Wx WxWxWxWxWx Wx WxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx WxWxWxWxWx WxWxWxWxWxWxWxWxWxWxWx Wx Wx W x W x Wx Wx Wx Wx Wx Wx Wx Wx Wx Wx Wx Wx Wx Wx Wx WxWx WxWxWxWxWx Wx Wx Wx Wx Wx Wx Wx Wx WxWxWxWx Wx Wx Wx Wx Wx Wx Wx Wx Wx Wx WxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxSDx SDx SDx SDx SDx SDxSDx SDxSDxSDxSDxSDxSDxSDxSDx SDx S D x S D xSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDxSDx SDxSDxSDxSDxSDxSDx SDxSDxSDxSDx SDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx S D x SDx SDx SDxSDxSDxSDxSDxSDxSDxS D x SDx SDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxS D x SDxSDxSDxSDxSDxSDxWxSDx SDx SDx SDx SDx SDx Wx Wx Wx WxSDx SOUNDERS FLOOD MITIGATION ANALYSIS Isolated Sounders Flood Volume Map LEGEND Cut/Fill Heat Map FIGURE 26a SCALE 1"=100' 344.50 ft X X X Δ SSxSSxSSxSSxSSxSSxSSxSSxSSx SSx SSx SSx SSx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSD x SDxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx Wx Wx Wx Wx Wx Wx Wx Wx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDxSDx S D x SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxS D x S D x SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx WxWxWxWxSDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx Wx Wx Wx Wx Wx Wx Wx Wx Wx WxSDx SDx SDxSDxElevations Table 1 2 3 4 5 6 Color Fill Depth (ft) [Depth below 20'] 0' - 1' 1' - 2' 2' - 3' 3' - 4' 4' - 5' 5' - 6' Range 2D Area 132,486 sf 107,077 sf 70,827 sf 43,602 sf 25,727 sf 4,834 sf Volume 319,932 cu ft 11,849 cu yd 194,385 cu ft 7,199 cu yd 107,306 cu ft 3,974 cu yd 50,561 cu ft 1,873 cu yd 15,059 cu ft 558 cu yd 932 cu ft 35 cu yd LONGACRES FLOOD MITIGATION ANALYSIS Flood Area Fill Depth LEGEND 383,748 sf 255,945 sf 140,312 sf 70,938 sf 28,814 sf 4,557 sf 249,436 cf 166,364 cf 95,693 cf 48,947 cf 20,170 cf 3,190 cf Floodplain Mitigation Specific Heat Map FIGURE 26b SCALE 1"=100' COUNT DESCRIPTION INSTALLED BY 8 CY MULCH CONTRACTOR TBD ENERGY DISSIPATION ROCK CONTRACTOR 54 CY FILTERRA MEDIA CONTRACTOR 26 CY 1/2" #4 ROUND AGGREGATE UNDERDRAIN STONE CONTRACTOR 1 FILTERRA FLOWKIT CUSTOM CONTRACTOR TBD 12"Ø SILTSOXX CONTRACTOR SECTION B-B PLAN VIEW R5'-0" TYP. R3'-0" TYP. 84'-412" 20'-0"20'-0" 38'-814"38'-814" 40'-012"40'-012"10'-0"10'-0"6"Ø UNDERDRAIN GEOTEXTILE BORDER (BY CONTECH)R262'-412"OUTLETDISTRIBUTION PIPE (NOT BY CONTECH) OUTLET PIPE (NOT BY CONTECH) OVERFLOW CATCH BASIN (NOT BY CONTECH)6"Ø CLEANOUT TYP. OF 6 84'-412" 40'-012"40'-012"10'-0"10'-0"GEOMEMBRANE LINER (NOT BY CONTECH) BBBBBBBB 6"Ø CLEANOUT (TYP. OF 6 PLANT REQUIRED, NOT PROVIDED BY CONTECH 3" MULCH TOP OF MULCH ELEV. = 15.17' ELEVATION VIEW 1'-9" MEDIA TOP OF MEDIA ELEV. = 14.92' 6"Ø UNDERDRAIN 10" UNDERDRAIN STONE TOP OF STONE ELEV = 13.17' 3:1 MAX SLOPE, TO BE STANDARD FILL (BY CONTRACTOR) OVERFLOW CATCH BASIN NOT BY CONTECH BOTTOM OF STONE ELEV. = 12.34' 6"Ø UNDERDRAIN INVERT ELEV. = 12.50' ENERGY DISSIPATION ROCK 6"Ø UNDERDRAIN GEOMEMBRANE LINER (NOT BY CONTECH)OUTLET20'-0"20'-0" 38'-814"38'-814" 10"Ø TRUNK LINE FILTERRA BIOSCAPE 714700-010SEATTLE SOUNDERS FCHEADQUARTERS & TRAINING CENTERRENTON, WAfor SYSTEM: FILTERRAPROPOSAL CONTECH DRAWING REVISION DESCRIPTIONDATEMARKBY www.ContechES.comSITE DESIGN DATA 3/29/2023 DATE: APPROVED: JMD CHECKED: SHEET:I:\MERLIN\PROJECT\ACTIVE\714700\714700\714700-10-FILTERRA\DRAWINGS\714700-010-FTBSCUST-CONFAB.DWG 3/31/2023 11:52 AMOF DJB DRAWN:DESIGNED:The design and information shown on this drawing isprovided as a service to the project owner, engineer andcontractor by CONTECH Construction Products Inc. orone of its affiliated companies ("CONTECH"). Neitherthis drawing, nor any part thereof, may be used,reproduced or modified in any manner without the priorwritten consent of CONTECH. Failure to comply isdone at the user's own risk and CONTECH expresslydisclaims any liability or responsibility for such use.If discrepancies between the supplied information uponwhich the drawing is based and actual field conditionsare encountered as site work progresses, thesediscrepancies must be reported to CONTECHimmediately for re-evaluation of the design. CONTECHaccepts no liability for designs based on missing,incomplete or inaccurate information supplied by others.JMD 714700 JMD SEQUENCE No.: 010 PROJECT No.: 1 1 MATERIALS LIST BIOFILTRATION MEDIA INFILTRATION RATE 175 in/hr THIS PRODUCT MAY BE PROTECTED BY ONE OR MORE OFTHE FOLLOWING U.S. PATENTS: 6,277,274; 6,569,321;7,625,485; 7,425,261; 7,833,412; RELATED FOREIGN PATENTS.®GENERAL NOTES 1.CONTRACTOR SHALL CONTACT CONTECH TO COORDINATE DELIVERY AND SUPERVISION OF PLACEMENT OF FILTERRA BIOSCAPE SYSTEM COMPONENTS (ACTIVATION). CONTRACTOR SHALL COMPLETE ITEMS IN THE LIST OF CONTRACTOR SITE PREPARATION RESPONSIBILITIES LISTED ON THIS DETAIL BEFORE CONTECH'S REPRESENTATIVE ATTENDS AND SUPERVISES THE ACTIVATION OF THE BIOSCAPE SYSTEM. 2.PERFORM FILTERRA BIOSCAPE SYSTEM EXCAVATION ONLY AFTER ALL THE CONTRIBUTING DRAINAGE AREAS ARE PERMANENTLY STABILIZED. DO NOT CONSTRUCT FILTERRA BIOSCAPE SYSTEM IN AN AREA USED AS EROSION AND SEDIMENT CONTROL FACILITIES. DO NOT STOCKPILE MATERIALS NOR STORE EQUIPMENT IN THIS AREA. 3.USE METHODS OF EXCAVATION THAT MINIMIZE COMPACTION OF THE UNDERLYING SOIL UNLESS THE SYSTEM IS TO BE LINED. 4.CONTRACTOR SHALL COORDINATE WITH CONTECH BEFORE THE FILTERRA BIOSCAPE SYSTEM AREA IS EXCAVATED TO MINIMIZE TIME BETWEEN EXCAVATION AND DELIVERY AND ACTIVATION OF THE FILTERRA BIOSCAPE SYSTEM. ANY STANDING WATER THAT ACCUMULATES IN THE EXCAVATED AREA MUST BE REMOVED BY THE CONTRACTOR BEFORE CONTECH CAN PROVIDE ACTIVATION OF THE FILTERRA BIOSCAPE SYSTEM. ANY ADDITIONAL EXCAVATION WILL BE THE RESPONSIBILITY OF THE CONTRACTOR. EXCAVATION DIMENSIONS SHOULD BE PROVIDED TO CONTECH IN THE ACTIVATION REQUEST CHECKLIST. 5.CONTRACTOR SHALL PROVIDE ACCESS TO THE EXCAVATED AREA(S) FOR USE DURING THE ACTIVATION OF THE FILTERRA BIOSCAPE SYSTEM(S). ACCESS SHALL NOT PROHIBIT LIGHT DUTY EQUIPMENT THAT MAY BE USED TO INSTALL THE COMPONENTS (STONE, MEDIA, ETC). THE CONTRACTOR SHALL BE RESPONSIBLE FOR ANY RE-STABILIZATION THAT MAY BE REQUIRED AFTER THE FILTERRA BIOSCAPE SYSTEM ACTIVATION. 6.IT IS RECOMMENDED THAT ALL FILTERRA UNITS BE WATERED BY IRRIGATION LINES OR SPRINKLER SYSTEMS ON A REGULAR BASIS. 7.CONTECH AND/OR ITS REPRESENTATIVES MUST BE SCHEDULED TO BE ON SITE FOR THE LIST ENTITLED CONTRACTOR ACTIVATION RESPONSIBILITIES. CONTRACTOR SITE PREPARATION RESPONSIBILITIES A.CONTRACTOR SHALL INSTALL PIPE OR SWALE THAT CONVEYS INFLUENT FLOWS. B.CONTRACTOR SHALL PROVIDE BYPASS PIPE AND RISER AS SHOWN ON PLANS. THE BYPASS PIPE SHALL BE INSTALLED WITH WYE(S), OR OTHER PIPE FITTINGS, AND WITH REDUCER COUPLING(S) FOR CONNECTION OF UNDERDRAIN PIPE, PER PLANS. PIPES SHALL BE INSTALLED TO PROMOTE POSITIVE FLOW FROM THE FILTERRA BIOSCAPE SYSTEM. C.IF REQUIRED, CONTRACTOR TO PROVIDE SHOULDER ACCORDING TO DIMENSION AND SLOPE SHOWN ON PLANS OR AS DESIGNED BY ENGINEER OF RECORD. SLOPE FROM SHOULDER TO FILTERRA BIOSCAPE SYSTEM SURFACE AREA SHALL NOT EXCEED 3:1. SOD IS REQUIRED TO STABILIZE SIDE SLOPES OR ADJACENT GRADE. D.CONTRACTOR TO EXCAVATE MEDIA AREA CORRESPONDING TO THE SIZE OF THE FILTERRA BIOSCAPE SYSTEM SURFACE AREA AS SHOWN ON DETAIL AND ON PLAN SHEETS. E.CONTRACTOR SHALL EXCAVATE VERTICALLY FROM BOTTOM OF UNDERDRAIN STONE, OR DRAINAGE STONE, IF REQUIRED, TO ELEVATION OF MULCH AS SHOWN ON THIS DETAIL . F.CONTRACTOR TO PROVIDE IMPERMEABLE LINER FOR BOTTOM OF THE FILTERRA BIOSCAPE SYSTEM IF REQUIRED PER THE PLANS. G.CONTRACTOR TO PROVIDE AND INSTALL ANY ADDITIONAL DRAINAGE STONE BELOW THE FILTERRA BIOSCAPE SYSTEM AS CALLED OUT ON THE PLANS. CONTRACTOR ACTIVATION RESPONSIBILITIES 1.PLACE GEOTEXTILE FABRIC ALONG THE PERIMETER OF THE FILTERRA BIOSCAPE SYSTEM EXCAVATION. 2.PLACE 10" OF UNDERDRAIN STONE - 2" UNDER THE PIPING, 6" AROUND THE PIPING AND 2" ABOVE THE PIPING USING LIGHT DUTY EQUIPMENT ONLY. 3.PLACE 6" UNDERDRAIN PIPING UNLESS OTHERWISE APPROVED BY CONTECH, ASSOCIATED PIPING AND FITTINGS/ELBOWS TO CONNECT TO THE PIPING/FITTING(S) THAT IS PROVIDED BY CONTRACTOR (SEE CONTRACTOR SITE PREPARATION RESPONSIBILITIES THIS DETAIL). 4.PLACE 21" FILTERRA MEDIA USING LIGHT DUTY EQUIPMENT ONLY. DO NOT COMPACT MEDIA. 5.PLACE 3" DOUBLE SHREDDED HARDWOOD MULCH OVER ENTIRE FILTERRA BIOSCAPE SYSTEM SURFACE AREA USING LIGHT DUTY EQUIPMENT ONLY. DO NOT COMPACT MULCH. 6.PROVIDE AND PLANT VEGETATION AS INDICATED BY ENGINEER OF RECORD. 7.PLACE DISSIPATION ROCK APRON AS DESIGNED AND INDICATED ON THIS DETAIL OR PER ENGINEER OF RECORD PLANS. 8.PLACE CLEANOUT ADAPTER, PLUG AND PIPING. 9.PLACE ADDITIONAL EROSION CONTROL AROUND FILTERRA BIOSCAPE SYSTEM, IF REQUIRED. AS WITH ALL OPEN TOP BIORETENTION SYSTEMS, FILTERRA BIOSCAPE VAULT IS OPEN TO THE ATMOSPHERE WITH A MEDIA SURFACE RECESSED BELOW FINISHED GRADE. CONTRACTOR OR OWNER IS RESPONSIBLE FOR PROVIDING ANY REQUIRED SAFETY MEASURES AROUND SYSTEM PERIMETER. TO MAINTAIN AESTHETICS, REMOVAL OF HEAVY STORMWATER DEBRIS MAY BE NECESSARY BETWEEN REGULAR FILTERRA SYSTEM MAINTENANCE EVENTS.800-328-2047 320-852-7500 320-852-7067 FAX8301 State Highway 29 North, Alexandria, MN 56308 Appendix C – Supplemental Materials 1998 Longacres Surface Water Management Report 2009 Longacres Office Park Entitlements Analysis Federal Emergency Management Agency Flood Insurance Study Number 53033CV001 1952 Response to City comments SW impacts 4-25-23 g8-121 (q) 00 rn cfl N cD 0 WG. DW1 1 0 V a 01 W 0 a 0 0 a w x N O O O 0 0 O N N N N O O 0 w J U W o Qry nn w Ld z It vz 0 o LL Ld 00 o a a N O Lir3LoCD. 0D0 cn Q w z 0 t U Q co m... CD cy zw I< IL L U z Lu Z on-WU L.mry J mi> cn U D jN OREN ONNINGAUG It 8 1998 44 00 1 4 k RECEIVED W W 0 U a° a) 0 c) of Q V W c rna c E L F Y' N C 00 4 0 cn o Z 2 Q U L U QaJ J V V 3 Hill Y Of a a Q w Q 0 z 0 0 z At At Ak it in - m RL An - --.A- PROJECT SITE DEVELOPMENT - RENTON, WASHINGTON 1. ......... I .................. I ..................... I .... LYNNWOOD 5 POULSBO •.. ••:•;•:•:•;•:•:•:•:•;•;•'•'•'•;•;•;•;•;•;•;•;.. . I..... P Z.... 0 ................. 1 ..... ..... ..... .. ..... BRE TON ::....4...... SEATTLE VASHON ISLAND :•;•;•:•:•;•:•:•:•:• TACOMA 40 SNOH_ OMISH CO. KING CO. 5 In KENT RENTON MAPLE VALLEY 1 6 7) / SITE LOCATION AUBURN KING CO. PIERCE CO. I I PERMIT REVIEW -SUBMITTAL DULY, 19tv 98 BOEING PROPERTY LINE 23-021 I s-oa ti PRCJECTI SITE 158TH ST. S i I I—BOEING uj o PROPERTY- w LINE Qf BOEING PROPERTY I LINE- I i fl i I I I ' I vN N N VICINITY MAP SITE LOCATION SITEPLANSCALE: NONE SCALE: NONE SCALE: NONE T PERMIT SET DATE: 07. 27. 98 J S.1/2, SEC. 249123N., R. 4E, W.M. N. 1 /2, SEC. 251 T. 23N., R. 4E., W.I. C 0 L6 N O O O N 0 m co o v N IN SET DRAWING NUMBER FILE NO. REVISION DRAWING TITLE IN SET DRAWING NUMBER FILE NO. REVISION DRAWING TITLE IN SET DRAWING NUMBER FILE NO. REVISION DRAWING TITLE IN SET DRAWING NUMBER FILE NO. REVISION c2,0002s.Dwc c2 DRAWING TITLE a X GENERAL DRAWINGS 1C D C5100033 STORM DRAINAGE - SITE PLAN 9L X5100034 DEMOLITION & TESC - SITE PLAN DEVELOPMENiP'.ti OF RED G1 G1100021 COVER SHEET - 1C D 11 C5100085 STORM DRAINAGE PLAN - GRID 11 9L12 X5100037 DEMOLITION & TESC PLAN - GRID 12CITY G2 C2500025 INDEX OF DRAWINGS _ 1C D 12 C5100086 STORM DRAINAGE PLAN - GRID 12 9L17 X5100038 DEMOLITION & TESC PLAN - GRID 17 U AUG 18 1g G3 G3100027 ABBREVIATIONS 1C D 17 C5100091 STORM DRAINAGE PLAN - GRID 17 9L18 X5100111 DEMOLITION & TESC PLAN - GRID 18 w G4 G3100028 CIVIL SYMBOLS & SURVEY NOTES 1C D 18 C5100092 STORM DRAINAGE PLAN - GRID 18 9L22 X5100039 DEMOLITION & TESC PLAN - GRID 22 Iz ECEIV 1C D 22 C5100097 STORM DRAINAGE PLAN - GRID 22 9L23 X5100040 DEMOLITION & TESC PLAN - GRID 23Q n 1C D 23 C5100098 STORM DRAINAGE PLAN - GRID 23 9L27 X5100041 DEMOLITION & TESC PLAN - GRID 27 w z w 1-- ( U z 1C D 27 1C D 28 C5100103 C5100104 STORM DRAINAGE PLAN - GRID 27 STORM DRAINAGE PLAN - GRID 28 9L28 9L29 X5100042 X5100123 DEMOLITION & TESC PLAN - GRID 28 DEMOLITION & TESC PLAN - GRID 29 moo L W Z 1C D 29 C5100105 STORM DRAINAGE PLAN - GRID 29 9L30 X5100112 DEMOLITION & TESC PLAN - GRID 30 QQN LL- 0 O W 1C D 30 C5100106 STORM DRAINAGE PLAN - GRID 30 9L 2 X5100043 DEMOLITION & TESC PLAN - GRID 32 3Ln CD Q 1C D 32 C5100108 STORM DRAINAGE PLAN - GRID 32 9L--K3 X5100044 DEMOLITION & TESC PLAN - GRID 33 2:3 w z p 1C D 33 C5100109 STORM DRAINAGE PLAN - GRID 33 9L34 X5100113 DEMOLITION & TESC PLAN - GRID 34 Om Q Q 1C D 34 C5100110 STORM DRAINAGE PLAN - GRID 34 9L35 X5100114 DEMOLITION & TESC PLAN - GRID 35 Q C) 1C D 35 C5100111 STORM DRAINAGE PLAN - GRID 35 9L37 X5100045 DEMOLITION & TESC PLAN - GRID 37 0 Ir 1C D 37 C5100113 STORM DRAINAGE PLAN - GRID 37 _ 9L3_8 X5100046 DEMOLITION & TESC PLAN - GRID 38 Z w X 1C D 38 C5100114 STORM DRAINAGE PLAN - GRID 38 9L39 X5100115 DEMOLITION & TESC PLAN - GRID 39 i Q p 1C D 39 C5100115 STORM DRAINAGE PLAN - GRID 39 9L40 X5100116 DEMOLITION & TESC PLAN - GRID 40 0 Z 1C D 40 C5100116 STORM DRAINAGE PLAN - GRID 40 9L44 X5100117 DEMOLITION & TESC PLAN - GRID 44 U Z w 1C D 44 C5100120 STORM DRAINAGE PLAN - GRID 44 9L' 5 X5100118 DEMOLITION & TESC PLAN - GRID 45 Z 1C D 45 C5100121 STORM DRAINAGE PLAN - GRID 45 9L801 C8100684 DEMOLITION & TESC DETAILS - SHEET 1Q m LL- 1C D 800 C8100177 STORM DRAINAGE DETAILS & GENERAL NOTES 9L802 X5100 DEMOLITION & TESC DETAILS SHEET 2 r 1C D 801 C8100--- STORM DRAINAGE DETAILS - SHEET 1 U L n.-s a) vin-- c LQof W W a 010 c 1 IN, C Q'NC c cr- v a) Q- ' LANDSCAPING PLAN BRUCE DEES & ASSOC. LANDSCAPING CROSS SECTION (BRUCE DEES & ASSOC. 1 C G C5100032 SITE GRADING - SITE PLAN 4L M 0 X5100036 IRRIGATION MAIN PLAN L1 Zi Ea P 1CCG) 11 1C G 17 C5100014 SITE GRADING PLAN - GRID 11 4L M 12 L5100370 IRRIGATION MAIN PLAN - GRID 12 L2 C5100020 SITE GRADING PLAN - GRID 17 4L(M) 17 L5100u IRRIGATION MAIN PLAN - GRID 17 1C G 18 C5100021 SITE GRADING PLAN - GRID 18 4L M 22 L510038! IRRIGATION MAIN PLAN - GRID 22 1C G 22 C5100026 SITE GRADING PLAN - GRID 22 4L M 23 L5100382 IRRIGATION MAIN PLAN - GRID 23 1C G 23 C5100027 SITE GRADING PLAN - GRID 23 4L M 27 L5100387 IRRIGATION MAIN PLAN - GRID 27 g 1C G 27 C5100032 SITE GRADING PLAN - GRID 27 4L M 28 L5100388 IRRIGATION MAIN PLAN - GRID 28 1 1C G 28 C5100033 SITE GRADING PLAN - GRID 28 4L M 32 L5100392 IRRIGATION MAIN PLAN - GRID 32 3 ffl 1C G 30 C5100035 SITE GRADING PLAN - GRID 30 4L M 37 L5100397 IRRIGATION MAIN PLAN - GRID 37 1 C G 32 C5100037 SITE GRADING PLAN - GRID 32 U 1C G 33 C5100038 SITE GRADING PLAN - GRID 33 1 C G 34 C5100039 SITE GRADING PLAN -RID 34 1C G 35 C5100040 SITE GRADING PLAN GRID 35 1C G 37 C5100042 SITE GRADING PLAN - GRID 37 1C G 38 C5100043 SITE GRADING PLAN - GRID 38 1C G 39 C5100044 SITE GRADING PLAN - GRID 39 1C G 40 C5100045 SITE GRADING PLAN - GRID 40 a 1C G 44 C5100049 SITE GRADING PLAN - GRID 44 3 Y 1C G 45 C5100050 SITE GRADING PLAN - GRID 45Y0 1C G 800 C8100060 SITE GRADING DETAILS & GENERAL NOTES Q m Z O_ V) PERMIT SET DATE: 07.27.98 O Z 0 3: c) c P-1) CD CD 0 Ln x 1-- D n D 0 14 c\4 1--*1 C\4 0 0 q- Lm] 00IO It 10 0 s I - , .::., . 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I : ; A ......................... ............................................ .... ..... u 1:: : i . . . ..... 1i : II : 1, 4.- : : : ............. --- I1: I - : 1, 1 ----- ---- :; ... A : 11! "O, -: I 1\ I 1, , : : I ! q " NOTES: I1 : i . i I -, 1'11 (D I. ij It = II .- I ........ - . ........ 10 :: :. - I-, .. . . Ik-,, , : ; : . e< 4-1-- 1::. 11 , 11 I . . z.: : N1 -, 11 III ': I11 II \ 11 , 1. FOR SURVEY CONTROL DEVELOPMENT PLANNING CITY OF RENI ON 1 I ; $ : e 1 i / 1 I I I1 ,,7% . 1 -- -"% 77 ........ .. ...: . ................................. --:. ... ::-..--:::;:::: ... -.: I V .... * ......... * ...... I .,.- -.. I - 1 N: : :: ! I 1 ... .. . - : : : Iol* : 111, , ... i ": . : k---11 I I . . Z-: fe I4 , : ; i.: I 11i . . : : I: . ,, i !; % \ . , i... I I : .\ i : " , , 1, : \ , I : :: 1:; , T.- .. 71:"TT : : :: , \ ; , yxzuu: .. -i: j: ; ; ! 1, . . : . . . i 1 "', '\ I 1. 5 INFORMATION, SEE DRAWING G4. I-- AUG 1 8 11%98 i! * . / / 1 ./ 11 / I I , , - I 1, .,-- 11 . " I2 11N I ................. - .... --- " :: 1 : : IIp I i. z - 11, - , I - 1. I .. /---- 11 :: : t, ; .-- I- -.11 I I r, nN..............: - - 11-1 i . " F , , , It ; : ,\!:: . II4; :: . i .. i " \ T r, 1IVi [ -1111: : "I I . I \ v : 1 %,\ I I N Li RECE IVED ry U ry n n T, I * I 11. I I!" ,,, /-. 1 : ii" "I I Ii. ;1, i 1 I - I ... ... - I L "' I... . I - I r - 1. / r 1- , 6- i w . , t %, 1 I., , , Z I 11 II , , I " I I I I 1p . , , , AV, A - , , AII / ---',. I / \ , , \ \ -- I - I / e I.. I'll1 I 11 , , " / I -- I \1 -k '.. - I x / -- \', 4: I I A I / .,, \ - K "- L-46-' .... I - ... .'.- --w -1-11'- .., . rm..... Iii ... \ t-- . . N , :, 11 I , " I :: I" " r::= ........................ :: I" ., I I.= .......................... I ...... I ................. m .............. . .. ......... 6.. W II ........ = .... I ......... .>.: , : i. Iff I 1 .- I \ ii 1\1I.r. :-: : : ;" i 'i . I Ii " Ir I : , ! ' I, 1 - . : : - "' 1:'j. : " ., 1111 , ---- --- -- - I =--=::- --:-, I t-- ---4-: -- I-' 1i I ; I '. I 1\ I ...... .... ..... ... ... .. ...... . :-- -;.; .... .... I ; I \ 1 I . Ii ,\\Iili.: : i : i , I ,,, ........... 1--.7.-.. 1 15/ I ;., , - : 11 : ; , , m;... I : - -1 ... " I i 3; mmmmm IT.i,=:a i i iI... - , , . , I : I I - - / 1 : i . ....... "`41,! 1Q . : 111. II I I I ,/,?,/ 11 I - .. II 11 I - ; " I11 1. q IX,-" \ "', , ", 11I I b 1. I1, I , 1, III11, \1ll1 ; . I , " \ 1' I., I 11 1\111 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. iuj11I ! I ! 1. It2.11%1111 I . I , /, " 1 . I " ... t , I'll , , 1/, , \ I - .. I 11I ,,,kk,7 --.- " I , 1. - - .! w , C. , ;1 I "' - \ , L-1-7-1-1-40;12-s- , 25 -01 I ,. 1 ....... I :. /. , tiI : :: - -* , , "! i : . .. : 1, i I Ij - :z I 1,-, , \ I , , . " \ H 41 .--- I- - ti1. : I - 1-11, ill,"", -.,-7,- I I . - , I \ , il 4-11'U--= "---, 1 I I - 1. ii.-.- 1, i 1, , . 1, : . t", i : : : I . I : , , iI : : /. / r " r I U I , I , , " \', / *. r t \\ \\ I 11 3 FOR GENERAL DEMOLITIONIt 3 00,oc, Z 41 LjE ti i I , I 1 :: I I : :i i I , ( i I11: ,-, / I ;. ,!/"."-// , , : \ 4.:,:::::, - --: 2", 7 - I \ 14 " "il . ! I Ir,'11?11111 .... ;',,,,,-' - I , , 111,j_'.11;1e'l . \ o.A.7"-,Ze.1 ',,!:*\ rt- 7 . . - -;;" - - - 37. NN .... \-- i-.r.---!,.--q5) , %. ': Ic 'J ,W. I I .,: I : , ,; 41 1. . \1. 1. : w--.- ........ \ 't&I 1 \- ; -, . l1',!: i 11 I 11, . ......... : ; i . . . R .......... ..... .. I : , " \ ji ... . ...... , :,.: I . \ 11,-. z! I I :: \,\, COD, wo i I I . :i a- LL1 :z I I it i % : 1- - " 5" - I \, , , x 1/-11 I'll", / I" 1;1// \ I ., I'll \ , 11 II. ..', : " //////";,/?/ i \ I6" 'I, , I 11,,A`, , " , , " , " " " " , " " " , " " , e I', 1'1","111, I . L: ;; Z. -m. I 1, -' ::- i ?II : c ,%L", ---4 - ------------------- ---- - -- 1 , e -c ,-, cm7-1`111 1 "ci , 11, - Z.: - I ..q : : 1. J.- =: H, : , 1::: 4: i . 1; : r:1 I , i 11 . - p . i : ::: , i I. .. 1: - : 1 !I: i ,,,,\ SEDIMENTATION C NTROL0 N r- to 00 14, v2 :3 0 to 04 o 4: Q (D cn < :z Lj z — cl- CD I . I . i II 11 11ii111---1A--- . II i is 1 11 I 1. I 1; *1 IA" \ I E X I $c's% T11VN G 1. - , ,; 1 -.- I I ; ,; I I , - II ,/ "/",,",-. , , .. .... .... .... 1. i - , "I '' ; ,.,,, 1, 11. I- f: : ... , V--, !,i4 el I I , , ///////// ,-, 1,1.,-, . i I", t" ;,;" " " " " " /, " / / / / / ? / / I IA f. / I : . . , " f : . . I `-; , 11j;l r, ,I, 11 11 11 11 / / I / / / / / / / / / / ),. ,,, e. 'A I. I'- .1 . - 1 I I - --. X'ellll 1'11'1'1 .1- I --- --.- 1111111 1111i'1141 - .. I , : z 'i"'. . e, i ; , :: , - ,/,/ //,/ ",/ ",/,/ ,,,/, //,/, / /, / / ,, "" A / - t,.-.::- I ... :.ti .......... - , i7 : I , I , " k,\ t / : , ni _- k , - o \e,\ c, ; , . . I , , ' I : v , . : 1. a... \ .'f1, I" : i : ji'Di ; , I1-:% I \ I'' " " I % I 1, % " i--,,'- 1! : 1, : n.................. ... 1----,- 7'. , - , ,,, , : --'I--.. ;:i ,---;-- I , : 1 : I: ; 1.:! : F". I . Ir , : ! ;"\ F . : . IIt ... 4 i - : 1 1 , 0 : . Vw : : : : :: : i . 1 -- 4 ; r . I 1 I .......... ; .... 1 :1111 , I :::::,. ;; 1' 1, ,: ....... . * - --------- 4,- .'.i-1ii .. . L, ''i, - 1, I /. IIj:: 7i -- j !I it i 'r-"i i i i I f tiv...r.,, ! I .1i , 7 2I ! ., - 1! NOTES, SEE DRAWING 91-801. 0 ') o (33,t Q Lj 1 1 . ! : I, - II d , I , . ---, e r;'1'1,1'11- . . . . . . . . . , 0 , . , I I I "'i, i,., " -- . . ......... A/ I 1, I I \ i . --- i- , e , - 1, - - jllj ... ......... * ................. ::::::::.. r ii4.. ,.. ii , ; HF-4 .t.. , - - - -**' i ,, J i i,/' . y ............ I I1 if , I....... ijlll -.'.-' -N... - I,., : F--': CONTRACTOR STAGING, U ry -- cj- 0 U50 - i lil 11i., t iI10, NDiCSTClPo U'i I I : i id jI d I rl,(/ v xxI , I I , - , " " , , "" , , I : i I " " " , / " 1" 11 'e,1-1 1`11 I I 11 I" " " "., , I Ii: I'll - I " I 7-1 X 1, Ile 1 11-xlx 1-. I \\ \--l'.... t.. - 1\ I :_': " -, i "I ........ N \ I I \ - I 0 1.11 - . . ............ -311 ..... I I , " I , . , I ......... 1- A. I I 1\ I .... - T-ilff - t, ; . . ! i I : T :. , y :; X ; ; . . ; KIIn "" 2'.,.,-,.,,%,,,,,,, : I \ ., -.-. " N i . If: . -1w',Ti;,--?, i. I , , IW - - -* - - -i I ; , 4",;N .1 ; i : : 1 I - .. I ', - , 1N! "I - 4 . \ ` Nl ........ D Z LdI, -- LLj0 1i Ii ilk i : I` . I 1! I ! i i; t:11 -- j: I /. . . . 1.1-1111;,eoe 1- 1 // /111 -",e);4, -Z/,//?/."",.7,11/It,,./,//xl,, z, - If., '. ,z , "' , 'o,tx, i , ./Z 11///,// 11:;! -,.;,,A1-1,111Z1.?,1'e_. lie,5,,-,,,, 1/// ,;,,- - I r;e .... 41" X, , I ""', 11/'111!111111]1";;,, t, , . _. 1, 0 : . _., I I f ,,, " -4: ", " I .. ii1-," . - , I -"- I iX .. . . ," ,--',.-' 1",//, 0 - ' 1 C,-4,-, , i ., . Ii. :1 . /,*" ; I , \ 11.1 II , i , m. : I . : I 1 ... 1`""' : I - - " , ! R, . , : 1I '" I : r - -- , 1. I 20 PREVENT TRANSPORT OF IL f) t :.. I j; L i , 11". .. I 1 c t !i! I Ili' il 11 . I L . a I 11111,,,x.;e -///'-/ I , 4-:: !;,,,,;,,,,,.,"" .... "," I I , Z,; ,, . 1'. tte. - .\ ----, v-;., --.'- - I - ill . 11'11,,,,11'-1111111. '--,-,,\- -- ------- 1=- -;,-:,-, 11; " N L \1 \, .1m_-, - - t" I - I .. , ±i' . x I - I .., 1 -L . , ,.,: , I ." i I . I I : - 11.11 , 11 , i:`f 1A Ii .-.- - - -- I—. I L - LL. I I I -! I . I . SEDIMENT TO EXISTING 2 * 0L 0 z Li I I It - ii II : i : I111 .. : i :: .. 6:; 'OSED I : : I I Li , ///// /// I I p ; "'I IV. I . L : : : I L- , - P-1.111 - - , l"'" --11 - --:c ,, . L, A, -kN, ----,- , I ft .7-,- );, I - . m . - - --.. Z,\ e I , - I ;a- ... LZ- -- -4.1, I L.', I L ... .... Im , \- C;, 1% . i ", i I .. : . I 11 - -1 . . I I .... - I I I . . I )- 111- 1- ji- I - - I I 1 ..... L .... 11 ; - i: It11III - , L L . - -j I III . 11 - I . I . I :-r-."x :,` I . I 11 .. I I.. L i , L I .L . I I I : 1 I : I I : L 'I', LL : - :, .... .. - L 1 :! - 1 -4 " I/ DRAINAGE SYSTEMS IN ACCORDANCE WITH SPECIFI- z IV - 0 bi < LL p Ro I i I : p :: 1. I . . L i i j 1. 1: . //1I % : 11 i - -" t V t : " I ,,- ............... I %,/,,,/,",,/,,/,,,/,,,,,,,,,, I . f 411.1:., , 'tzl 11 'N.... I -: 1L , . , - U 1 .. ., 11\/, 1, - 91 il ' ,,', - " A. :::-Z I - 1.1 -" L : L I11I ", _ I . 1. -.,. F_ L L L' Ie, . .., L " I II , , - L.k", 1I'll L . I I I L . I . .. I . I V ` -j- I I - . . . . . ; ,; - I ,L.11- I" ,,, , I ,: 'i", .! I L I 1 1. I : v . * ., - - I I , , L . - I I . ..,:.,-, .. f - ,,,, CATION 0271 0. L 01. M ry 11I : I ;:: Itf . I D II i , ll,",,,////////// i 7y II . ; 11. . yxe,,111,111",I, I : I7 : i: I , , I I . , ' '' L L L:'-,:,---:'i, - C _ , I I .:, I " `.- . .. I ,% I I r l" I II; -,5 -" 'I, i 'I, 1' 1 1 i : , I - I .. . I ,4 :1 : I . , L -1 1 -.. - I ',I.. -. 1 - - III : --; , I - , . I . I - L I . I I I : , ; ' L 1, I I L ---. I . I - I -- , ' t Ii1111 -:.11: I I t I, L,; L' IffII Z" -'-- LIi'T i I . a - D i .1iq L : I : L I1. q I 11 I . I -/,/// I , '. I > . , - I 114717,71 I'll I .1 I1-1 le I I I1 . I 1; I , 1_ - 1111 I '. I _ L -:;,L L so > cn L . I i t .. il yv ,/,///////,/// I , I , I . - ,,;.! I L, I I I , . 1 , I \ -1 z", - I k r : ; ROUTES NOT SHOWN. No 11 LtiI :: i . ; : : I . t : I . II I I : . , I : I :.: L:' t I IV I I I I " / , , , "' " "' " '' "' ............... ' "'' ...... I I 11/11, I ,. . I I - , . 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I\ti -1 w , \ \ \\ : \ - C, I : ; I I 1 1 i 1 : L,\ I.... .-.----' / SETQ I r ; , Ii t k t : i: t I t : . I : I , : i41i : t, , ** I . 1, I1, \ 'r \ I I L* '' I \\ ,\ \\ 1, " t,,', \.: \ \ \ - . , 1, I I \\ \ '\, L 1, " L I r / / I i I I L - I r I I Lr , , / / , L i : .r ., i . . / / 1 L . I ". Ir i I :; i Lui : 7 .1II : I : i -- a:I : I I . ....... . . r ,/ I* DATE: 07.27.9 8I . : q I : I L . :1 t L .. r r. r : I 1.1 .." I 1, k' , - ... L ... 11 I I \ \ I", 1, I I I LL I I - 1. L , \ ,\ 1 I " . I . . I.", I I \ .. \ I L \ L I 1. I- \,\ 1: 1-1.-, 11 ' L - L 1, , I ': ; I .1 / fZ., I . I r 1 I '. L ,. r 11 le I ,. . 1. I. I I I I I r Z '3 ' i : x, i i I iii : I : : I ; : zr : ! I I : CID r L ... rrrL ..... .. r ...... .... L L i q I 5 >T IL . 27th STR E I I \ L I --,.,-,. L I : \ 1 " L, , , I \\ 4,), - I. 1. ""'....".. -' .. 1, .12 .. , I : ": "Ill I I ---:--:----: --:,;:.---. I I , , -, .1 .. ...... .-: -.: K ,, , ,, . . 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CN 0 0 N 72,200N72,200 0 0 0000 0 LLJ Un DGE OF POND W TER EL. = 8.36 717,198j VELOPMENT PLA N qING CITY OF RNENTofN AUG 18 d uj RECEIVED i; ( o 10 z LJ MAIN" POND zQ0 NOTES: z 4" ( 000 C) C 00LdCIE) 0, 0) 05 LLJ n 0 000( 1. FOR SURVEY CONTROL 0000r- 0410000( 001" CN 100oc- SSCOIAERATION 00 0 CN 0 0 Q 0 C. 1000(. t INFORMATION, SEE 0 10000c. 10000( 0 0000f- B OMEASURE 06r, DRAWING G4. 000 VU-) LLJ 000( T F OF WATER 0 = 0410000( 0 0 0 0 0 r- loon, U) CLof 000(- 2. FOR GENERAL DRAWING b oo10000cL.LJ10000c. 6000 j -J, 000(. '00— oor: rill NOTESAND SYMBOLS, Ld L _P 0 0 0 0 c U 10000Cloor" SEE DRAWINGS G3 LLJ U9- Mo AND G4. cn 01 0 3. FOR GRADING NOTES, SEE 5 'DIAX '0 AB 0 VE U <ND p Lj LFfl,22 DRAWING 1 C(G)800 z PSG. E Y me 00 L 4. PROPOSED CONTOURS AND Sp spSPOTELEVATIONSAREp (7 D$p EDI $pWA TER., E 8.3 sp FINISH GRADE. REFER TO E7 spspLANDSCAPEPLANSTOso7/7/98 ...... ........ DETERMINE SUB GRADE ELEVATIONS, 0 A 5. AREAS TO RECEIVE 6" C) 9" DIA. 55UOIAERA-TIGN --- — --------------------- . ............ . ...... 175' PVC_-- VA'LVF in IMPORTTOPSOIL TO BE OF- -VA-L--VE, El ...... . 9.12 ------ ----- TOP— '0 VA L VE, EL. 7.8 TOP FE- `1v ------- - -- ........ OF 5 PVC--- - VAL VE ......... . . . .................. . ... ....... . ..... CONSTRUCTED 6" BELOW f O coFINISHGRADE. FINAL 6 PLOt . ....... K . ........ .... . ...... TOPSOIL WILL BE PLACED cfl-0 uJ00 4) dA ....... !.,. 1 --1 DURING CONSTRUCTION OF J j ... . .. . .......... . . ........... . ....... ..... . ...... . ... 41., _4 ......... .. ro ------------- LANDSCAPING. AREASTO L RECEIVE TOPSOIL DENOTED o fLARCELI . ......... ..... ....... Lj ARCELA i;v; H d) 00 WITH HATCHING: CE ------ cj r\ j p ocn 100 E .. . . ...... . ..... ........ m CLlbE roC (u).......... C (71 ... ... ..... 4: L3 N 72,0 N 72,000 ...... ....... WETLAND "B" MH UNDARY130 4 ....... 0 2 MW- 39 jss EL. 11.07 93 7- 121-4NjZA R z 4A 0 - — — ------ — — — ------- ----- ------ z N iN Q MH 12..?, 2 M Xo" 1A X ti i pilla- 0- - ---- -- uj r 11. cn m ETLA D BOUN A y 0 0 A." Ni Ln .... .. LLJ N z0 Lf) J* Q 20' 10' 0 2.0' 40' V,; low p lim l'' 060 I ITiF 4 i1 iFfftlii IN IL j7 rag 0 z PERMIT SET KEY PLAN SCALE: NONE DATE: 07. 27.98 0Ja 00 N n O m 0 0 N O O O Ln U O O N N N O O m w ty CSZ0 0 Z 0 W a w W 8 VU1 O a ao r- N r- 0 m 0 0 a w X 0 C? N N t CITY AUG U Li ryQOna z nzco0)0 LLJ00 L3N O w 00oIt Vn UQ CD zo2uw NNLL Q QZoNm1EQ r CD Z ry O F- W 0 0 zw 93 zw< L mll JDIN> cn U a0 N ° I T Op of h Q V W w 0- L) c° E Q) E mE C w C c" A N Z O J O Q z Of Q w Q 0 r. Z 0 LLJ PERMIT SET DATE: 07.27.98 J S. 1 /2, SEC. 241123N., R. 4E., W.M. N. 1/2, SEC. 251123N., R. Co W.M. DWG 1C(G)27 NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4, 3. FOR GRADING NOTES, SEE DRAWING 1 C(G)800 4. PROPOSED CONTOURS AND SPOT ELEVATIONS ARE FINISH GRADE. REFER TO LANDSCAPE PLANS TO DETERMINE SUB GRADE ELEVATIONS. 5. AREAS TO RECEIVE 6" IMPORT TOPSOIL TO BE CONSTRUCTED 6" BELOW FINISH GRADE. FINAL 6" OF TOPSOIL WILL BE PLACED DURING CONSTRUCTION OF LANDSCAPING. AREAS TO RECEIVE TOPSOIL DENOTED WITH HATCHING: L Ctom 11 11 l ff l jj r u KEY PLAN SCALE: NONE 0 z U'' %- I DT 1 HN NW IaUJ aN mW a N OJa 00 rn n N O m w 0 0J0. WW xX O O N N N O O O w wJ U- 00 N N Y Y DEVELOPMENT o Y OF R v AUG 18w Q RECEPV) v ui n n 0 W w I- Z 0 z o 0 O LL w o aQN O wy3un o ; NC CNunQZ O N N ly Q C:) cD Q Q LL ry C' z LIJ 0Q NW CD r Uzw16Zw Q L Ow W mry wo- 0 O O 0 Ln U O O N N N O O O w W L 0 n— o O O 3 Q V _ w W a, o E Em E Jl Q'NC I C p V N d L, z z o K U L a m U 03 Y Y o L a- 0- Q Q 0 Z O cn O Z c I J Ln N i cp L0 m O N........... Lo X I N 71,400 1 I X I I jI I t X f N 71 i f X I ; cr) 00 o d' M -44 EL N 16.51 N M - EL 5 1 69 00 D N 00 II tt iLn W PERMIT SET DATE: 07.27.98 J D37.DWG N NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GRADING NOTES, SEE DRAWING 1 C(G)800 4.PROPOSED CONTOURS AND SPOT ELEVATIONS ARE FINISH GRADE. REFER TO LANDSCAPE PLANS TO DETERMINE SUB GRADE ELEVATIONS. 5. AREAS TO RECEIVE 6" IMPORT TOPSOIL. TO BE CONSTRUCTED 6" BELOW FINISH GRADE. FINAL 6" OF TOPSOIL WILL BE PLACED DURING CONSTRUCTION OF LANDSCAPING. AREAS TO RECEIVE TOPSOIL DENOTED WITH HATCHING: S. 1 /2, SEC. 24, T. 23N., K 4E., W.M. N.1 /2, SEC. 25,123N., R. 4E., W.I. w POND SHALL NOT BE FILL-ED UNTILL PROPOSED STORM DPAINAG- SYSTEM IS APPROVED By OWNER. mP, Pop., m IN00 IUl rr KEY PLAN SCALE: NONE 11 4HN NWr w UaaN ujW w UN f- OJa 00 N n O m w a0 0Ja W x DEVELOPMENT LANNING Y CITY OF R TON o r-- AUG 1 8 1998 U o RECEI ED 0 w I n n 9 w z W F- 0 S zC- W LLI D o ow Q ZZs3NOW ao - v' m QQJ O m N W z CD DD m _ G W Q M F=— o Er of (/) z F n IL O o^, V / W U0w w Lz z0V) x L. O w m a 30 > i) U vV) L a• r aD v I- a 0 + rn O O O E 70 U < W' 1 0>L lrr, n LJ In4 c Q) 0 O E- v C I- a E NC I L. 0 a (( J b2 9 D f— d o h N z O 1 Q w ib U LL_ U a m J 3 •Y Y8 fLW X 0 r % n O O O Ln X^ V 0 O O N N N O O I- O 4i 3 W w Q 0 z O V) O z ii Y ti 3 \ y o; Yi ., 6 rr ~,, ; r L! i i y y ; ,. 5 TO W 1 6th S RE ` I 1 t "" 8 tyg _.. : n........,z..............,..,....................,............a,...........--.-.....,..P$,.... r x , I ., Y..-.. ^ }?k r, , r ....-.... .......... 4"'.......... .............. .., ...... ......... 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R N x; , ! i; ' : a { 13 i A : ' I: I, ` i' I ., f i 13 I.. a1 Iyy I 0II I i; < i t., ai ;\ 1 \ \ 4 . \ \ \\ t ; i\ i i r\\ f i 3: 3i d..Y is : 3 .R. I :. i33 [ jjt ! ,` \', `/ ':\ a: it i X 4 ;' i \ 1 r i t i1 I I , _- I itt ti" I iA •:.t I i t it W a -r 1 \ UFi \T \ .\ E Q 1 S: i S t r 1 a'\ .,.. i. j{i , I c j 1 X 4 x ! fI I y:. i, G a t • iII i 3 1 is I. , i I i ,..... - i M I I.... ......... Y I j I. Ij F x > i 1 ' Ii. i pI y ' jyt, ; .. , 1 F... .. • a , , , :: mot i : ', f i `. t, : :t , i f r 3 f xi 4 .! . J 01 r 1- 1 I r 3 11 o I. i t \ , \ f I f - i ;: i } . o \ e \ , a J a a' ! . 1. l J// 4 s t _ _.. I Y W 2 th STRE 4.. Elx I, a \ -._ , as'... ,... ,, 1 j' i i a 3 s Ali .,. r h i I i X NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. N 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE RAWIND GS G3 AND G4. 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOT ES SE RAWINED G 9L801 CONTRACTOR STAGING, LAYDOWN AND STORAGE AREA. CONTRACTOR SHALL PREVENT TRANSPORT OF SEDIMENT TO EXISTING DRAINAGE SYSTEMS IN ACCORDANCE WITH SPECIFI— CATION 02710. CONSTRUCTION HAUL ROUTES NOT SHOWN. CONTRACTOR SHALL PREVENT TRANSPORT OF SEDIMENT AND DEBRIS BEYOND PROJECT LIMITS IN ACCORDANCE WITH SPECIFICATION 02710. W i© r jP ai I1II t, m Sri y; aar a{ a.i' I Irdl C 1 S a v I c I ...cam. I.GII r -- i 11111 I 1 I r I s r l Ir• 11 ill t u BitPA, rl/ i` ij . I'r p/' 1 2 i i J I,ir I.-%i/, I plc. r1 I r_, m I 11 KEY PLAN SCALE: NONE s.1/2, sic. 24, T. 23N., K 4E., w.M. N. 1/2, SEC• 25,123N., K 4E, W.M. PERMIT SET DATE: 07.27.98 i t, V 001 "'k1i 4 0 an wCL w I 9i 00 Ar ... ................................ ................ .............. . .... EDGE OF POND N TF 0S I 0 VA' 1, \'(: P , , \ i I I, \ , I " ) 0 iq -:f.! L RWATEREL. 10. -3 5 X. CULVERT TEMP. = 60' F OFL ' P 0 NTIME: 8. 10 AM VE:R T IE12" RCP X CU EDGE OF Rob, EDGE DATE. 612198 11 8 RCP XATX E) 9.81 /A 5 / . ..... N 8.98 717198 717- NAVERTPONDD '\ lELC::'MEN IETPL X, ...... / I YOFREN10,!/E 36" Rcp ---- ------ - .. . ............ . ........ . ...... PCP ( W) 9.88 UL ER w) AUG 18 1991 E 1, Ld36" RCP; MfH (4'1'51HIPRA7) 9imCUL 1ER11T IE 3 5" "P J. (SE) 8. 01TP/ P0 68 F GATE IEL. y0. 35 l" " ;I '- ,, Of9 DIA. 1AERA TION 2- X w/ r/ / / / / / / / / ii \` % / ' \\` \ UNA--- 60 A&ESS S JcjC5 PVC VALVE x TOP OF VALVE, EL. 12. 91 LJLLJvl 4- 0:) v ...... LL- LLJ Z 0 0oo m'0 x 360Lu0 00CIO < N LLJ ;7 0 7i) 04 L CUL VE R T VEm < CULVERT 4 fl . ............... v"' .,,'\ i R Z ---------- U Q: 1E 12" RCP (SW) 9.194 C) ry LACE WA TER EL 9 57 ptil ' P 'xisSGlI6I,1AZRA P N ZLumPAVEI!_ SDMH 19 "161A 0RIM = 15.67 INAPLEct-.- I TO &JEASURE 7E.* X30 )A Mh" 1E 36 RCP (N 8.53 j < VAULT I IE J6" RCP (S 8.53 FVfL 3: 0 A WITEfe 11 VlliCSTC STORM WATER 0 0 L /' / / / rat ....... zEjDETENTION POND AND 05' D;A 4 RW LWETLAND M0. ABOVE G / L l 21 N 4 x t F/ Tit Do > v) W/ PPkC BASE O. 0 TYPE) X\ .... ..... ............ ............ ............................ .................................. ........... .............................................. ................ CUL-VER-T ........... ............................ . . ................. X", /I 0 C) 0 E E- 4 2 uJ 0_ 4W a- c cv EZOO 3: V) V) C-) z Q_ cn CL LLI Q F., z 0 V) 6 z N 72,400 V D I c > l A F"CJ (SW) 2 o PLANTERS vN 72,400 tk A V V C IIAE Wr A NIE O C/ FU L WA TER FV- = 18. F2/M IT* hhh T/ N ... ...... :Q9" bi _'CQ Af Z N LID Aj CULVERT ABANDNEDGUY A HOR 1E Xl' RIP XW),—Z 614 0 ilo S) Li KA. /SSC e(IA 4,",AT/4NuM/ T R ry V L OF ALL/ 6LP F L)E, I PROP SE(b)" SH PILES 0 R'I Q DEMO ITI LI IT It TE5;, E 7/ 98 3 I PPW1CONCBAE0 CD N* If 00 7 41111N00 Lo A - I 1! 2 0 0NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR STORM DRAINAGE NOTES, SEE DRAWING 4. FOR STORM DRAINAGE TRENCH SECTION, SEE DRAWING — 5. FOR STORM DRAINAGE PROFILES, SEE DRAWINGS — 20' 10' 0 2.0' 40, S. I /2, SEC. 24, T. 23NOIR4E.OW.M. N. 1/2, SEC. 25, T. 23N., K 4E, W.M. r PERMIT SET I DATE: 07.27.98 @NMI. a-;umlf o llw RAW Fh illto] Ellim_ m I_-Affil'iE' • l 1I11 Ilil ON vall, " III :' I IBig, mil,® Full, mm KEY PLAN SCALE: NONE V) L'iCk: 9 0 z m0 00 cr) L Wwx 00 04 CII-4 s N 72,200 0 Un DEVELOPMENT PLA NING CITY OF RENT Lo G 18 1(119 Ff aR E C E IV D - ----- 1/72/,2-00/ 0 X) Ln FUZEZ/ (I p(XD W.4,,TFR E 8 3 l7l'ilg8l SSCOIAERAT10a SUIE F L OF PROPOSED SHEETROP / E PlLt Sl ORNG// ot X p. A ............... 5 ro S /sr sp/ 11 ir! q, / . . . ..... A AT 0 L H JUA FfC- - V' 411 IA % / / / / P/ ' , / j" ' .._ ' .. / j 9" 2. ZVE . ........ - - --- - ------------ ------------- .VALVEC" yc VA V VEI EVEEL. 00 . ........ .. ........ 9- . . ... .... ... . .......... oGb u0)(b ------ -------- C) ...... .... .... ... ........... ............. . .......... 0 v PROPOSED L/AKE/----/ NAERATION/RE QIR ULATION siSTtm WE ND "E' PR POSED ENLAR EMENT OF CS u A Rf. ... .... DE ENTION POND ND WE LAND DE IGN S RFACE L=8.5 - ii iiri ir ll. iiiiiiiiiiiiiii _.i it __,i __ii ii %ice ii, iiiri iiriii i ii i iii 10 h, BOUN A Y v 0 0 0" 00/ x; co Ln LLJ C5100097.DWG I C (0) NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR STORM DRAINAGE NOTES, SEE DRAWING 4. FOR STORM DRAINAGE TRENCH SECTION, SEE DRAWING — 5. FOR STORM DRAINAGE PROFILES, SEE DRAWINGS — z 2-0' 10' 0 20' 40' 0 S. 1/2, SEC. 24, L 23N.j K 4E, W.M. N. 1/2l SEC. 25, T. 23N.9 R. 4EP W.M. PERMIT SET O DATE: 07.27.98 J- MEMPMR-liffilt'l IEll-51910 imi fflw'u V, rall alim 0111 1,010*01M4 mmin EilIIF, a of, IEmI'll MOEN®''I'Ifft'll 11171W-1vIRAulII all-imm-112momm"ll Essull ri'll ma, m®m KEY PLAN SCALE: NONE NWr CJ a aN QW, 6a W UN FOJa wxx 0 c6 O O O Ln U 1-11 O O N N N O O O w WJ W r4 W W F- OJa 00 n CV cD J U Y a0 0Ja wm x INWN IVJ 6a CKw EL EL Ww X 100 105. DWG I C(D)29 DEVELOPMEN"' I-_ CITY OF u L1J AU 6 1 0 ry R a- n z U4 o z zoQ) zoo0U Z n 1 1 LJ LC13 C Q) om) 0I 1 LLJ 0LLJC, 4 co N o 0 1-4 It r o m C Qf E M CD ry LLI V) 0 I < IL 3: O V) v a' 0 160 Z LLI cf) U zuj- Q_ X LLJ0V) M ry n 0— 0 0 CLQ) 0 C) C, * E- 3 - 0 Ld n Lj c 0 E0 3u 3 E E O) N cC c)) C z 0 V) W zV) 1b M J Of ch CL LAJ 19, 0 Sri 0 z 0 0 V) 0 Ln u I-' 0 0 0 0 0 O L9 I N 71,800 777 D 0 0 000 0 EMj d) Ln LJ LIJ 4 1, 7 i I ... I.i,.__J A.. . ..... 0 LLJ BUILDING25-20 0 A V ii ti H ... . . .......................... ............ ... ............... ..... ....................... . .................. .... ................... . 4p: I — _-_ - -___ .......... ..... a,..,.. .. J- 4 ......... .......... .................. .... . . ......... I ..... .. I ........ I ..... 7 . .............. ......... ......... .......... ....... .. .... I ........ ....... ..... 1 .......... Z .................... ....... .. . 4 12 " W 6 4-4 ........................ t //, /// // / _ i/ f /ll1 lllllllllll llfllllllllfl/ll 11111111111111111A llllllllllll/ll 11 1 l j ' r j 1i . ........ ............. 1 2"W F_- F.- 11:. r . I i d 4 f..... ...... ...... ............ t- 4-- J. M I y 1_ 4 A I I if 0 0 0 0 00Ln u t Ld LLJCITY OF RENTON RIGHT OF WAY cr ui tZ I m z 10 I o LLJ u ry I NOTES: 0 I i1. H FOR SURVEY CONTROL n INFORMATION, SEE DRAWING G4. A— .......... ............ ............................ y ....... if 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, l` ` SEE DRAWINGS G3 AND G4. N 7 1 8( 3, FOR STORM DRAINAGE NOTES, SEE DRAWING 4. FOR STORM DRAINAGE SEE DRAWING 5. FOR STORM DRAINAGE 1 PROFILES, SEE DRAWINGS l FOLLOWING APPROVAL IAND ACCEPTANCE OF PROPOSED STORM DRAIN- AGE SYSTEM BY OWNER, 10, FILL EXISTING STORM DRAI k FULL WITH CDF. 1. 00, A 0 0 c\ j It tr) Ld 20' 10' 0 2.0' 40' 11171f S. 1/2j SECS 24, T. Lim, K 4E, W.M. N. 1/2, R—Cle251 T. 2. 3W. j R. 4Ej W.M. r s I PERMITSETDATE: 07.27.98 L — _ ® _ trwr' INIII" IM I I ST.! . KEY PLAN SCALE: NONE S, p - <&-- / aq 00 c1_4 D 0 DEV5LOPMENT P ANNING CITY OF RE:N TON v L,j AU V)Q roy REOF D w n o Lj Lij I.- :!5 z z It S0. 9 z 0— I,Lu m0 oa), 0c) 0 LL. LLJ0LLI U-) co (6 0 CD c1_4 f) < < 03 O.TozcN cy ry 0 ry LLJ 0 j < D N 0 "7- Licry z LIJ < 01, V) ui L m cy j no 06 0 0` 0 0 Ln 0 0 N C14 0 0 0 Lj 0 Z j a A < 4 . . .... . ............. . .............. .... . ....... . ..... . ...... ifllal Ln o fl 7. i I PR POSED STO : DRAINAGE COMBINED WE—LAND/DETENTION P N DESIGN SURFACE E =85 ch ob is ii I I% 1 11 0 N it Ln (o Lo 'I- m o 6 6. 7 ez Y., J. A, it 6, h, PROPO• ED LAKE AERATIY.,STE N/RECIRCULATIO14 S ' It z it WEtLAND„H„ ,' i ! f` B 0 UN DPRY IC; it 40 CLEAR AN( ) GR B DITCH 44 5 51 EL i PLACE GEOTEXTI E FABRIC IT/ le 691 AND INSTALL,, G VEL AND I 0 `''PIE (TYP) RFORATEPE T 'V RI R 00 VV I T N D If. BOO ARYSDMH,, Lc) I E I IN (E), itI' OUT (vy) E AI SI]WH — n. IE 24' P (E) = 8.97 I 't'- IE 24" (STANb PIPE) = 3. 3 24' STORM DR I BOT. 8" B FFLE 6.261 qNSTRUCTION 108.D NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE' DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4, 3. FOR STORM DRAINAGE NOTES, SEE DRAWING 4, FOR STORM DRAINAGE TRENCH SECTION FENCE SEE DRAWING 5. FOR STORM DRAINAGE PROFILES, SEE DRAWINGS 7777 7— EXISTING POND "B" OUTFALL SHALL NOT BE REMOVED UNTIL LINE IS CONSTRUCTED AND APPROVED BY THE OWNER. OUTFALL SHALL I— ................................ I— .... . ............................... . ............... BE REMOVED TO EXISTING MH. MH WALL SHALL BE i ?? SEALED WATERTIGHT w/CONCRETE. i N 7 18" DUCT FOLLOWING APPROVAL 1E (W) = 6.09 AND ACCEPTANCE OF PROPOSED STORM DRAIN— AGE SYSTEM BY OWNER, RIP —RAP REMOVE 18 ILLDIPANDF POND "B". EXI'TING POND "[3 STPRM DRAINAGE c OM INED WPOND/DETENTION POND POND WA TER EL = 6.9 11: 47AM, 719198 6 4_ RCP 1E (S) = 6.19 mmka, 7 CONS TRUC TION N-7 FENCE . .... . ... . ... . ... . .... .................... so I E' IN- IE OUT(W)= N E 4 V 20' 10' 0 20' 40# n S. I / 2 SEC. 241 T. 21Mol. j R. 4E W. M. N. 1/2, SEC. 25, T. 23N., R. Co W.M. r w IPERMITSET DATE: 07.27.98L Lp >I! 1 if illl l rifll y III 50 55 60 gym DNA`® KEY PLAN SCALE: NONE 9 00 O DEVELOPMENT P1 AKINING CITY OF REEK- N w AUG 18 1 oRECEl\l`7D ry n CL_ Lli 3000 LLJ n c go 0 uj 0 :3 tocn < 7 os Lr) 0 4) LLJ c3 q Q: E CD Z LLJ => 0 I_ I e-r r1ol w N 71,400 mq 0roZ o 7- LLJ uLd... Ll 0< 1, M ry D IN > cn go 0 18" DUCT IF 1E (E) = 6.) POND WA TER E L = 6.9 11: 53A M, 719195 S TORM CON TROL STRUCTURE TRASH GRATE TOP EL. 13.1 RIM = 11.79 IE 24" RCP (E) -- 9* 2 7i 1' i IE 6" PVC (W) = 8.74 ! rj RIP —RAP N"_71""'200 ---- - ---- - ----- - ---- - ----- ...... . . .......... 16 an x 7 H PARKING LOT AREA x", Nx N'' NN NNxN N NNNNN SDMH 7 RIM = 15.16 1E 24" RCP (N) = 6.76 1: 1E 24" RCP (E) = 6.77 Is N. NNN" N' X' X' NXN', N'llNl`, N NN' N' 1 N" Uzi 4. NNN d T) POWER SFORMERTRATPA 00, N i i i x x CONSTRUCTION X EDGE OF PAVEMENT 0 SURVEYED ON JUNE 1998 SDMH 0 RIM = 16.89 Ln IE 24" RCP (E) = 9.06 Ln 24" RCP 1E 24" RCP (W) 9.069.06 ui 24" RCP o x z 0 V) j C Ln POWO Box w/:: 12" CqNDUIT it ii NO UD) I i. it I I co I! #iiiii3iiii H H 0 0 m(.4, C5100109,DWG 1 C(D)33 NOTES: 1. FOR SURVE) CONTROL II INFORMATION, SEE 4 DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR STORM DRAINAGE NOTES, SEE DRAWING 4. FOR STORM DRAINAGE NN TRENCH SEC LION, Ii SEE DRAWING 5. FOR STORM DRAINAGE PROFILES, SEE it DRAWINGS N 71,400 6 FOLLOWING APPROVAL AND ACCEPTANCE OF PROPOSED STORM DRAIN— 4 AGE SYSTEM BY OWNER, FILL EXISTING STORM DRAIN FULL WITH CDF. Ef> REMOVE EXISTING MANHOLE, FOLLOWING APPROVAL AND ACCEPTANCE OF PROPOSED STORM DRAIN— AGE SYSTEM BY OWNER, REMOVE 18" DIP AND FILL ii i.: POND "B". ii H N 71,200 5 10 15 25 Wl 1* 0.11 r;- gym 0 z PERMIT SET KEY PLAN SCALE: NONE DATE: 07.27.98 NWm 15 ZOJ OZ mO a rN Nw w VQaN Q: w Qa 4i VN OJa wWx CD n O O O l() U F N k 00 O o rl_ U EVELOPMENT P.- Y CITY OF REN- 1G 18 19 O : CE. Qclfnn z0Liw Z so Uz 1 1 w - QQ 1 O w W t 3 ,N a 7 u Q Zwz O NN Ir Q Q ca D m I>: ry 0 C z OQ ry O W L U 0 Z wQ L mom V) U N a0 O O 00 O Q 0 E cfl QN Wn I-, c 7) 0 o a m E a'NC Ad z > Q `g U L U a 3 m Y J Y ry d Q W H Q w xX CD 0 z 00 O ry U 0 O N N N O O 0 w 71 ,000 00ot 0000(. Oo00C loor- Q°L1o°o°C or. 0000( 10000c00r. N 70,800 i ILn I I WETLAND PR POSED LAKE BOUNDARY ER TION/RECIRCU TIbN YST M 6' 1 G AR AND RUB' .DITCH, I LACE GEOT TILE 'FABRIC 4ND INSTALL RAVEL'\AND PERFORATED P E (TYP) 6' 1 I S` J 1 , N 71,000 1 48,0 ODSED J J' 0000 ° `. i°r` r J J\\\ 00' 00 CDO00, O ,or o. X X — JO°C X X j °°°° N 70,800Or 20' 10' 0 20' 40' S. 1 /2, SEC. 24, T. 23N., R. 4E., W.M. N N. 1/2, SEC. 259 T. 23N., R, 4E., W.M. PERMIT SET DATE: 07.27.98 J NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR STORM DRAINAGE NOTES, SEE DRAWING 4. FOR STORM DRAINAGE TRENCH SECTION, SEE DRAWING _ 5. FOR STORM DRAINAGE PROFILES, SEE DRAWINGS _ L • riff KEY PLAN SCALE: NONE NWK 9 ZOJ OZ mO 1 N NW kl U ILN W Ga 00 n J U Y tJr- 0 0Ja w x 1 FN NWY W aN KW a Ln O O Ln U 001 1 E-:.DWG 1 C(D)4(- I W Z O z m0 a V1 0 a 00 J U w 0 F- O a WXX 00 o a o go I b CITY OF RE AUG 18 ` W V y --D a- a_ Z w 0,00 U W d 00o a0 a a N L WL.,J i 3 ,* 0 QQZ oz" m wQ Q 0N` r.. u Iz fy zW IL OJ 3: O L0* zwZu 13 —OQLm cy J 07 U a° a) Q O a V r r w D a c Q Q E m C N I CC Q1 Q Q) Q-7: Z Q Z i 0 U 0 gY V) Q U QQ. 46 m J Of d a a w m I N 71,000 76 4 0 o w X, 1 r I I i i j i a_ CLEAR AND f I GRUB DITCH, PLACE GEOTEXTILE FABRIC AND i INSTALL GRAVEL i I AND PERFORATED PIPE (TYP) 1 f` r' '% X i f I t N t i i X i i i X t i j r j i i 7 r j r i X 1 t r: t • a I 1ti i 1 1 tr. vx o io o L r r A i O 0 c9 Ln w 0 0 00 w N 71,000 NOTES: 1. FOR SURVEY CONTROL INFORMATION, `-)EE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR STORM DRAINAGE NOTES, SEE DRAWING 4. FOR STORM DRAINAGE TRENCH SECTION, SEE DRAWING __ 5. FOR STORM DRAINAGE PROFILES, SEE DRAWINGS _ 20' 10' 0 20' 40' z 0 rK S. 1 /2, SEC. 24, T. 23N., K Co W.N. N N. 1/2, SEC. 25s T. 23N., R. 4E., W.I. PERMIT SET DATE: 07.27.98 O iz Kill' Lila® Iff" K0 ORI Ef.._. gall. I m Eli KEY PLAN SCALE: NONE 1 C(D)44 z m0 Q 00 Wwx DEVELOPMENT I CITY OF RE wAUG 18 0 n z LLJ 0o' cc LL_ LLi 0 WLn1 LLJ 00 It 0 v) (_5 U-) ZC14 z c-10 Q < ry u z 0 Ld< I F_ O CD L 0 7- Z is Ej- 0 Q, Li mo 0 - I-_ cn wo L. 0Q- C E-4 0_4 EcoE N cc: 'mp D z 0 T_ cn w CL a- ui z 0 V) E>j 0' 0 z N 70,600 68 n C-4 MH MH MH 6 "S cil0: C)- Qo: FH tn LLJ 1-1/2" W 6 9 WATER\ VAU LT 16 VEGETATION AREA ll CL 0 U 0 z Ld 0 m LLJ it CITY OF REN,,,T,,ONj i RIGHT OF---- VlAyII cn Lli 0 m cn wW TZ < 0 LLJ m to cn y 0 Ld Ld 0 V) LLJ CB TYPE I TOP = 15.44 INV = 13.58 12" RCP IN SW." INV = 13.44 12" RCP OUT NE. • 70 FH . CB TY P EPN00 C B TOP = 170'3, b- INV = 14.89 6'-,.,PVC W. ` 'NE INV = 14.85 6) PVC S. INV = 14.77 4" PVC N. A . INV = 14.77 12"'RCP E. S. .. D. . ---...-.-.--..-.- - ---- ._........... . ..... ....... . .... . ............................. G CB' - TYPE I CONTROL PT#8 O\ A" TOP = 15.70 SET NAIL INV = 13.88, RCP IN ELEV = 17.81 ........................................ INV 1 6 " PVC IN S N 70466,62767 ASPH/-LT s E 53967.§530 INV `T3.85 12" RCP OUT NE zl . ......... . ....... . . ..... ........... . . . .... . ....... . .... Ln CB Ld 0 u 0 Ld IU mNU.; V KING COUNTY ATION AREA--,,,, NOTES: CLEAR AND GRUB,, DITCH, 1. FOR SURVEY CONTROL P LAC E',GEOTEkTI LE 6 INFORMATION, SEE FABRIC ' AND DRAWING G4. IIINSTALL GRAVEL Z_ FOR GENERAL DRAWING ANDPERFORATEDPIPE. ( TYP) NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR STORM DRAINAGE NOTES, SEE DRAWING WETLAND X'K\\..4. FOR STORM DRAINAGE BOUNDARY TRENCH SECTION, SEE DRAWING 5. FOR STORM DRAINAGE PROFILES, SEE DRAWINGS w SEWER EASEMLNT r. M M H N 79-,600-" m i V Y, 0 o CN Ln LLj 2. 0' 10' 0 2.0' 40' S. 1/2j SEC. 241 T. 123N-1 R. 4E, W.M. N N. 1/2l SEC. 251 T. 23N.l R. 4El W.M. r PERMIT SET DATE: 07.27.98 L KEY PLAN SCALE: NONE 6 P- I - / Z, 7 j4 a U 0w0: I 9 6 z m0 i 0w w V( V) Kw 0 i VL I- 3 wx 0 3: 0 4 r4) 0 0 0 L0 x I--,' D 3: 1-1 0 CD N N I--,' C14 0 0 lq- 0 Lii I Ij L I - I : ij \ , " ..... 11- i f - I I , t! I : I : I I ::: 11- I I ; ; I, I X5100034.DWG 9L 00 O 14- 0 I 9 a) i5 i ti , 11 - I! - "4i,, ,.; tj . ;. . t ik ) I ;f -1, " 17.1- /: I I II - I . i . C - i -, 4 I I , -, i I , : j! il'M I I 4, : i I , .1 \ r, ..') I I : , II ; ; -\ V: i , I \('.,, 1, , 1. i , I ;- , -". ; 1 : 1, . , %" I . - : : I : I II -,_.. : I. I I . I . : , Is :; 1 . :: 11 wtI I II .. u 4 , , i- * I ................ INr`1 1 I , L L . K , ::: :4II1:: 1 1 . :. : z . I : i "I i V , tt I "'i ,i , , 1. TII I i I I. t , i I *,.', I I . . II11I 1, I I '; *1 , t I 1 , , ", I " IINI I 1'\ N NOTES: vi 0 W, I 2 i ;: . I \ 1 I I , - I 0: , , Q1 " W h S! TO " ' 1 6t 1*1 : I W . 6i : . . . . . . _. f "," - :7- . - 4 :LI : N -4, n- I t::::4: ::::::i . i II It4.1 --.---, ., , I Ivl I. I :: - I ; - I __ f, 7 1 I ", 1I I II0. I i . I . 1AE 1, . L. : . i I . . I ....... .. i .... e...) . ...... -. .................. ...... . . . 41-** : r : I _........., I :: I :7.-'.'_ f,", 4iI ... i,- - I ......... -- J. I . . ...................... - ...... I - I I-— i liii '- , : I 1 I ! I .. L._:Ir. -11-`".: 7 - _' I . . i 1, 1, 1. FOR SURVEY CONTROLI ; 1;1' i ; 1. F. I I I rl` ;; i I I. wi U 1I I I : irl'M_. I I . ii L, / I k I i / I" I 1III et'. I i - I 2E!;;:: 11\ I eN, ,- _Wcoc"o- il-:,--,- l*.---"-*-,.-*---*-.-,-:::i:i:!, I ..... ...... w ......... ..... . - .... - . __:::=:, I ... .............. ...... I - __ I I _- . I I ........... 0_1 _ilo-- ... # ..... -0- .. ......... : ...... I : : i 1. : 11.11- - - 4 , ' r- -11.17 I : II : I........- .. . ..... . ... - ....... ...... I ................... . . . . . . . . . . . . . . . . . . . .. 1 : :. IT i 1, ,\, r. I : : 1.. III iti i ir . . ................ i... 1 : ;; ; a -, , it : .... - __ __ 4 .. t:I I ------.,.-,- . I 11 fft:.:::: ;* ; 4 i t i : : t.::.. , -, 11A 1 , ;, jv :', " . I 1 ,, , " 1, 1, II II , " 1, z : , 1, ."'\ 1 5 INFORMATION, SEE I DRAWING G4. NDEVELOPMENTP CITY OF REN 0 Ld AUCI 1 8 1)98 I ,,-,I,., - FON i if 'i / / I1: k/ i / I I! I / 111 /Ir / ,r- 1 I ill , / / I I , / : w ....... ............. ,.-'%"5 ............. 'K . .......... ............... 2.,.... . .- ... I .............. . - 11, .1 , ". — I 0 , — I .! 1. - , I I ,,,--,-, I . I IiI " " I -, I 1, , I I , 11I /,/ / I I I ; I7"'77-7-1- : : -1III a I A. I : 1qwwwww+ rww- --------- - I ... I , owma .,.,_,.,._ I : ITY " II 1 I C: II A 1_, . tu im; ;: I ... ..... .. ... ...... - I I1—: t .. v I11\ I: ..., j - i\ I . ; I , , t .1I11 . : I I e I q ! t , I I X I :; T 1.. :i Mr -::::::: : ... :::!:I ! i,[; il11 .. i 11 I " " I ,,, I , I ,,, "r, 11, 1 II " 1\ ,n.Y,N I ,q; ", t, e.), 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, v ---D 0 L1. - ry CL ch 1) W 4. , I ,,, md ", .0 ,__ I1 1VI - ! II ,,, 1Ii11 ; I i, , _; - t iI , : 1. z =: I /i - rI __ wI ... [ I' " I'll \ I 1 .., \ k .. . .... r/ 11 . \ \ \, I _1/ \ \ X I _- \ 1 / I I . :, / I __ I i: :, "I / " \ 1, - W. " " I I i'll i I z -- , , , 1111 I // - I IIV ,..w _,' \ I 111) k - I / - 'N - 4 i ;,i ... % ;, *1.7-" ,.,.,.,.,.,.,,',-,..-.-,, 3, ..; . .*:.*.*.'.T.-,1,s -, i .-.1 t;i.-.-.-.=._."04w..- , \ I", vl.';,, 11 ...... . 11% I I , 1 - ', , I. ....... ... -- 1\ 1, f1 1" A.- IIl ...... 1 ... -4 .... . 1 .... 1, ... .4 ... 1! 2 . I : 1 i : ,* i . I . It11 . w.... ; - r " . . w:.,TtT!1.-- t _', I .- ; ` ; L4 - !I. ItTr : i I I.- - _.: 1i .7. - 1: 4. . .: .. .". I - f, W: 7-jj-.!:-; 1 -i . 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I " 1W . ::: \4- ij- - -.R.- - - - 1-.t,_- : : f" ., 2: i ^, I I 11 ,,, - It1, " ,, .2 1111 \ II I1, I , \ - I N._ I _-. :_ - A PREVENT TRANSPORT OF SEDIMENT TO EXISTING I 3i m 10- % . ii : 1 !!I ; I , - -- 11 Npi C-A 11 . 11 \, ,.I 1.1ZV/////i1/////,`//,0///1-/ I 4;,:. 0 I _,_._\ iL ... x j / Q_ " - I * i , I . i t iil ii / ,,- , , L .. .... 13. ., p ... 'il - J, I -- ...... ..... - . a-,4.. . _f " . 1 f"I'll: -11 .... "I ... 7 1 V,-;?-* i i! I11 : I 1, 1, X\ ; " " I11 \ ." -'*,,, DRAINAGE SYSTEMS IN a 0L CD ujz t:i w 1 ! -`i i1 I : : t : 1i t6- - i ; N PR 01 'O SEDI i t :. ............... ,` I I I L,,- ,',',,,,',"" i l 0 " 1 .". 1, ////////// 11 i : , .A 0, y -,,////////,,,,//,o 1"',/o,// ,, , - , "p, , - - 6, "',-t7_1- N ----- - Lx , q, -q, I..... . . ..... * ...... . I11\ \ %_ _ - 111111.i1 ...... ". 1,`/ , o ,..- o, N - ;W:. ., - it I . .._,___. . 1 1 m -, - , - ..' . I .. ; ..", / t.._ I - i ... " _/,\ ... ;,: : . 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':- - It ; . f ............. . ............ t: - I" I.. .1- 4 : I" : :" L 11 43, P-,q 1- - I ,-A -- Nwa' UaU2OJ O2 m0 H N w U Y wIxx 0 C) N O O L V JY V) WN W QEL cetJ GQ. 0 ri ww x W Q U 6 z q 6z m0 L LJofx 0 3: r-) 06 r1l) 0 0 0 x 0 0 CN N 1-11, N 0 0 0- D Lj 3 jL 040. =.".. l.l. i-/'`', I t 1I I I i 1I 1II' 1 iJ 1 12: i I 111 I/ I 1 I 1/ 111I II " I 11 111II."III1I1 I I 1I%I1I1t ii i m\_ A I m- I — t I\ 1111 rLI I \ I1 . I I \I 11 \ \ 1 I , 1, , I 'I 1... 11-...1.1I 1-! I. ........... . . .—.... .......-..,..-...-..,.. N9OL8T0E1. S XI51. 000G38. DWG N EDGE GF 00 //I --.- -POND Il 0 / ---- _ 1.__._-__-..__"0z/ WATER EL. = 10.3/ / _____ I qI. . , e, t: 1 i III L 1 I K, I, I: I .. . I , . I j J\ 1 b /-, b %" . 5 " N// 1\I/ P I E 11 TEMP. n, 60F I / I, I ' lI \". I 1\ I 1\ I \ I I 0 0 / IVERTCUL - I,,, 1..-: I \ 1) TIME: 8: 10 AM ,,) uw /// -/ /\/ /\ 1, CU VERT \ \ L1.\ 11/ I 1 I i1 A . IE 12 SP 4" \i /1 RCP EDGE OFp 6--, 1 f A.... 1 I' I_ I I.. .........-. 1- 4-..-.-... I. I 1-.'., 1....._........._--..._./. /.. //,/- 0._.... L....... ._ i- I P: RDEVENT TRAN. SPOR ROLATE98 1 TP4j,\ 8 I , 11" // IWATO,01=/.521... /_ 114.,- PO \ \\OEVELOPMENN 8.98 D62/ , EDGE O 1/ R--.," INFORMATIONSEE CITY OF REN 1_\ I "--,n- ii;VER T POND 1i i i1, / / / . 7171O 7 /98 \\\ \ DRAWING G4 1 E -6" RCP \ // 8i \1 I 1) Y,, ) ...- W= -9.14 I I '.iUL\ ERT"4 \\ 2. FOR GENERAL DRAWING '/ i IE 1PCP = 9.88 / l/ / / j OTES AND SYMBOL/ S, 36 Rc I ) i RER4N "! 0 . CUL- MZ(64'TR 6HIA"//,/ / / / / NGS\ 3 0I IE "P(E)8AND G4/1 ,I;, ZlM9; // SEE DRAW z 11 \," `i ,,, % ,91DIA. SSCO1AERATION . T F OF GJ ATEEL— 0-35 \ 11 1 _ -, I,> W11 " & .5 PVC VALVE / /A&E - O ACCESS 7 / / / / / / / / / , , "_. \j L, k T = , 3. FOR GENERAL DEMOITI z _ 0N " TOP OF .VAL VE, EL. 12. 9 / LO N U , .\ 80— // ... I / / / 0 I / 1/11I /I"/.I /tIt \ SIO coo ) -i.p. 1\\ /,/, \ \ SEDIMENTATION CONTROL I 111 . : I I ic ; / / / /X/ / / 11/. ",, t/ NOTESSRAW L? COI" ING rLn 0 L: T . lam b, * : / \ \ 7 . L: 1 : ; EXISTINTORM N, o t — CULVERT .!iV // ////// / /</// / i 2Q1E12" RCP (SW) = 9. 94 ---*.......- \ )\ b CULVERTSYSTEMS TOAGEBE I 0y0 i 5 / ; . I EMA I- . _ . LAKE . 11.. r _ s ; ; IN WATERLP. 4 '-f/I I "/,` 95I I 157 .__ I : i ; // / / / 19 IIA-SSC,AgRA \ I < I 1MI I .6= t1/ i .- 1 T1 / EXISTING LAKE I . I36" RCP ( N W) 8. 5b5jTo -AS RE f i 3 -< iE30 AM UNA I " EAOAND RECIRC/761E 36RCP SE = : 8.5d / /(FXL E / ULATION SYSTEM TO BE a /// AIN: i i, ///z — rcI // / / /////////:/ / // / / "1/i< ! 0I Ii) I 1. 1 mQ/ 1.1 I 25DIA )0.4 ABOVE \ \"LAYDOWN AND STORAGE G, 1 o XC 112)CONTRACTORSTAGINoc : / ./ / / /SHAL / 9 \ \\ o pp :W/ 6cLE ,I TYPI : I ,.i / V / / / ///////////// .. _/ t \\1 TO EXISTINGI IMENTSED 1! "1;?_ i 9; : ; /: .; / / / / / / / / / / / 1. COLVERT f ............;.......... .................... .......:IDRAINAGESYSTEMS IN i i E 4PVC (W) = 8.42 0 I i, I1 / CIFI 0SACCORDANCE WITH SPE v0 ! :".) // / / / / // / .................................... .........................................................................._..........-'** ...-...*...*....*.............CATI iC1 N 7O 0 T , v) N 72,400 - i ! 0 P9 PLANTERS N 72, 400 F..; ///////////////, X \/ i -- 6 /, a) I\-1 A \ ,'/- E ! I ..:.....I7i-; . : C1AERT! ,f, O /_ I i -- . TER //-.z.....z ... / /./_/ / i \-. FULL,(%.WA 410I ,; / I C: '47) 1FI%"., 1)i , 1 a.. : I -_ .../....._ q i4: j , - 07 ! --............. i ..............', bi%vARi I5 -__ .........................................../ / SILT FENCE/ CLEARING I , VNOPLID/ 1 i I LIMIT FENCE (I P/ /// / / / / / / / - 1 P . • : - ? .- 0 2- k ......... . .1............. COINCIDESWITH t i : I1< --- -/.... i DEMOLITION LIMIT / 9L b29, 111/\/V i1/ / A / / / / ___/ / / / / / / / / / / / / // /,"-// / / / : t I / . i... ...... z T -: / / I i,, j1 i ,: /I , T0 0 1. VIRRIGATION / \/,, / / / // x ./ / A/1 w2 . , I I: . ABANDONED \ LET , --I/ 1 I MAIN 1 cfC . : r , " 1 i GUY ANCHOR 1 VR% I %i . : : E IIPXW/ 614 HI REMOVE ALL TREES \ /i."\/ / / / / / / / / / / / / "-/.-V / / / / / / / / I : /,/ b WITHINDEMOLITION -_, " ;/ / 1 : . 1 L(Y) I ,I I , / , // / / / / / / / / / / I 1 ii 0 J011I / § ,61A. / sC1A.TN / / / / / / / / / / Ee T' O:% ii !! r I 1 m !, 1 .'5ILLOF. I DE 31- 6 01-/1 i/ I `i' 4 6 FL , 19 1/ / / / / / / / // a0 CLEARING LIMIT ' 1 0 6 FENCE ( TYP) /1.., . / ---- ,.. A' / / / /I I PROPOSEn,SHEET / 4 1 DEMOLITION LI/ // I INCIDEWITHM.f : IT PILE- II S.k.IdII R1IN..G , . I .. "- /.. I 1. v i ( DEMOLITION",,LIMIT) 7)< : ! ............................ L_............4 k .................. .. ...I i : . i 4- , 1 L,'. i h . tOG0F.4i. 6N r7'198 / / / / / / / / / / / / / / / / /.11/ / / / / / / / / / / / // PROPOSED ENL M ,1"/ /1/ /I , / / / / / / / / / / / / / / / / / / / / / / / /pp W/' CONCBA - L "\1 5 1 DTETIONPON0ANDWETLAND / I I TYP.) -4.DESIGN SURFACE EL= 8.5 / 1., / , 1I*/ / - I \- 0 co / // 9-LrL/ / /# 7 P.. D . / / / / / / / L/ / / / / / / / /////.'. I N . 22t/ 72-200 b,6 z 0 20' 1 O' 0 20' 40' V) I I = 1 5; w Q II S. 1/2, SEC. 24, T. 23N. j R. 4E, W. I. N N. 1/2l SEC. 25, T 23N., R. 4E, WX I PERMIT SET 5 z DATE: 07. 27.98 - L________ir Im I' ll 2rd, I M N Milli,fl I r IIl illI I I i 11,111 100-11- m m gym KEY PLAN SCALE: NONE 00 O N 0 Q 0EVELC; CITY OF AUG 1 LIJ Z w Z Li U Z no o 0) W LL_ w LL 3 O V I N o ; Ii Q N o : u w z tr Q o my U Q D Zry 0 OQ J IL 0 zw wLUZ_ UW Q IL OQomJ so> cn U o a) v o; Z E- O 0 E Q p C E Q'NC C v v a'(7 O a s U Q a 3 m J YY a a LLJ 0 z O L N72,20o o /,//',//////////////////o N/72zoo1 ` o Ln j,wA / 89LANNING 4TON / ' STABILIZED ' ;` I' -; QED CONSTRUCTION CSTC STORM WATER IL/ ENTRANCE 6 \ DtTE1 TION r ON I A yy TAN 9' 2 9L 02 ti/q. J/ 4 6I I . I \ Ij ` 00r, o o o c Ik o' C0 11AERA TIO/No°°o0oi000010O00CYAB MSU E oor `oor' OOOc 000cSUETO F L OF WAR t 000c I ', 000c' p P \ .• J 100000cc o00oi O O O OCI. OO ^ • U 00, P t NC1 ...-... P Q.. U ....... i p TOP . a ,_> P 5 P. is i I PROP OSED ENLARGEM T, OF CST 0'` PRQ 0! EXD , ET-/.WA... . ' DETENTION POND AV Z_7WETLAND SP 8 I _ / / / / /.. ,/ EO L 10 llil T / PROPOSED 8 DESIGN .SURFACE FL 8.5 Y t IRRIGATION _ 1 1 1MAIN ._ :... o w - P _. . P ., - ..IA. SAC /rL A N .. P 0/ ERC- V.0 - VAL 2V E . Z7F... 7 F F' V VEl EL. - 7. 71 a.-C.. PARCEL 1 i ° SEAL MH WALL % PARCEL ``f ; c — — A - e 14 o _. .. FOLLOWING:, PIPE ; 1 ;,, _ _ / / / / / / /` / / / 6 VAL [if 1rt WEZI_ ND Mh1 r . I4` ' `' REMOVE ALL TREES WITHIN DEMOLITION LIMIT ( TYP) x /%/ MItl 3 / w 8 / P z/ f .,. CLEARING % IMIT FENCE TYP X COINCIDES: WITH 1: DEMOLITION LIMIT xx h: i i < i f i J Wes'//// t - i BOUNDARYIV z 1 3 1coCN co r Iit w 1<. 100039.DWG 9L22 NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 9L801. 4 EXISTING LAKE AERATION AND RECIRC— ULATION SYSTEM TO BE PROTECTED AND TO REMAIN. CONTRACTOR STAGING, LAYDOWN AND STORAGE AREA. CONTRACTOR SHALL PREVENT TRANSPORT OF SEDIMENT TO EXISTING DRAINAGE SYSTEMS IN ACCORDANCE WITH SPECIFI— CATION 02710. 20' 10' 0 20' 40' S. 1 /2, SEC. 24, T. 23N., R. Cl W.I. N H. 1/ 2, SEC. 251 T. 23N., R Co W.M. PERMIT SET DATE: 07.27. 98 L J[ 0iffilauum IME) l F11101MEN11 El£ l lil llli, I malmi Em m gym® m KEY PLAN_ SCALE: NONE 8 r.--"f ( a -7- 2 0 9 0 _3 6 z m0 , V) LLJ Lj CLV) wL.j n 81 0 3: 0 6 q- 0 0 0 Ln x I-' 0 0 N A 1-1 N 0 0 0 w 3 jL_ 00 I , I , ;) i-\." L I I . , 11", % K72,200 L I11 ` * , ., I : . .. , - ; : , .,.-' L,. _ IIII .. .. 0 - .., 1 . -,--.*,4'-, il p ", 6 - I ...... mw L'/' , x . -, k ,%': z .11 . I I I . " , 0) n /N ;,, 2 (6 / / / ,O/ / / / / / / / / / / / 1 g'l' ,/ / / / /,/ / / / / / / / / "'00 / / / / / -, 1- 3 ., , ;,i,' is , / I ... _- -.', , ..."., , :1111 i csz ,A , ,_ . I .. . 1 I . , '.." _ - I- N11", , 1 I ,! ' i I e , - :- " " ,, -,) \ 9" DIA. S-5C , i 4 " I ` - 'r_ OIA ERA T/ ON . , ." !, I 1, ,\...\.,, , Ili iI , l tf) , - ,) ,., , NOTES: q1v-.-- ,'""I X'X. ,--, , 1. ii .- / "'.,.!, ! " ", 1, I 0C11114 , I /" i ;. I ' i 1; . " ..7 '. ,, , _, ,,,, , --, , - - 16 1 .4.. , i . I 0,-_ 0L/ / / // / / / / / A Z .... _ / / , ., , UNABLE rO OPLN I -; , Li P `? "', . 1..... , ", , - , .,.' Ln i, . L . J, ) 1 . . , 9 _./ , , I - . , I , - , _ I .1 ". "? ! ., .......... , ,.. 11 - I?, , \,, li - ,,,,` z - I ". . ___ 6 -It ' ", 7-- - - ," '.. I . _ , 11 I . I , , : . . I N \ 4 1 - _-__' .. - ___ . , ___ II . , - - - I JAMMED ), 3 .. ) 1. %, , . , - .. t - "I r ,/,--/'., . 1_ v ( m - x / I , -- ------ - I . I , , LID JA*M 1 4 11 , L'j .. , ) .-, %. ,*I:i "",.;:_lll I ' 1, -_ / / 1; ; 1, ,; - . I \ , , , -j 4r l I , " ,Lot. 11 . SI - 1'._,( * , -- V--, "'..".. '` " , ;,"i ; t -`,''-- 1. FOR SURVEY CONTROL Ie v . i, 11 \ ' Ill..- .. % i ; 9"" CSC 21A RAT ON "': , -; " t, . / I , * k, ^ I 11 . 0. ; . , -, ,' , 1 1-NS, " t i V. " . . ') \ ... I I " " " "'. p ll-, / , 0 tk `1 .' 4) ll- 'll - , I I L "' ' r , i ". t .'. I "" . - ; ' 11 - le , , - \1 I I_- - 1 . - " , 1, %, v, .- INFORMATION, SEE I / ") . .-. ... .... .*r 11 , - I , * I \, - 1 I ' ""'; __" .""'; " , 11 , - I B _Il _I-' .'_ I ;A _ ""I - / I, , - 11'___ -', - -,-, ", ii, 11 -"**"' .. ...N 1* ,-:,-""','\ v: ,jl-:l ,A:v, I . - - __ , \" — -, , .. . ,, . . .- , r.. ........ LL ..... ' ' 11 . . \1 6- - , I1.1, : " .,e I .1; , . ........ 1, - _ , . -I .i,- .......... - ., - , 'c ,,, 1 %'., 1. '"- . , / '..- I " ' r . I - , - ',,, / I . --- - _ , i ' '. J'i';,,,` , L ", " ,; .,,* , - / II - n,L7 / , I , / -_- .... ..... I , , j ,,, ; 1. 1. , - ' . 1 6 DRAWING G4. U , " ,,,. 1 W #5 / " - /-: - / / / " I ,,'_/ / ,/ Ul L XE4S\URl'- ,_ " .. 7,11. '_ Z, 6 _ "....--' I , --', L ,__ J- L > ", EoY ' - - __- -1 l _"-: I l "' I ! 11 , I ` . / - . " "', ll,_5 "I / i. , `;. I L . . t_: ,_ " \ li%, ,- ,--. - , /--l-, I - I I 11 . L' " ." 7 . 11" - - / , -.1 -1- , .1. r - w, : , / "', """ I : t'r " I . ;,, __ * pp: 0- . 1 2 5 " DIA X. ,0. 4' ABOVE GROUND I * , I I I 11 i- LZ, " I .. -y, : , / , ., 11 li 1 - ' , L - - . -1-•, . - I , , " " , t I " .1 , f I , I i ,", % " , " \ , FIL .- - ' L .: j . I " , , . 1. 1 : . ,', j., I I 11 I I ....... 11 - - ".-- TOP - , . ': ' , / _- I I ' I, , ...... ; , ". 11 . 11 . ... - I , . I : , I , t " -_ _ "f,_ " J L ,% r__ . " - .;., I jl I ,. ..." 11 . ,,,, ., I L 11, I i., t., . ..... -, .; " I'll . 11 I 1, - 1- 7- - ' - - --' -, I I I I - " , / , , _' 1- 11, -, . , , , DEVELOPMENT " / / / / / / / / / / / // - .... / / IEDGI IOIF N16 . " _ /U . : / / / / 11 __ l_,:: l:_`4, 1: 'i , OF EL. `- ", 12.--98,,--, I ' ' ... -,, , __ .,----,\ ,,, I " ,, : - , - " - 11 i .1 - ........ . ......... , - ; ,o CITYOFRENT)N STORM WATER 1 ' - ;,. I ,_,".'___ "", STQ , I , - . . 1 I..., : , ', !L"r " I _:_ , ; , . 1 I . "' - t, I - , , '_- r, ,-,' 3. / ..... , I ., .1-, "'' L 11 ,r 2. FOR GENERAL DRAWING I ... I . _-, ... ... .. fD ; 11 A I . , " " '' - I .1 - IV.-, , : _ - - , . , : L, , 98 /,--' 1, - ", , / "_ , . ,/ I .... :, . . _ --- , 7;? ;,'/ ' " / / ; -!/ I p , -lw- - - E- L' - , 7 -- " ._; , _L' , ...... i I / _4._ 11 A,T EP,, , - " " ------ -., -, 7- / , - , , " ;,( ..." . - I t _ I .il, , 11 : I.. pI -.,\: , .1 : "I p .1 I -11 e 0 I - ....... . !.- w /m: I I I , - , . , .." . 1 , I % ". - ! .. , 1 11 % ., , _ I `:. , I . . " . ,*- . : " ;, f' * . . NOTES AND SYMBOL, , , : , , L.. ;,: - : I I" : / , - ...... Ow. : ." ,,:. ", I I . ! ' ...../:— AUG18.1 , , l..r",l-",-,__,l" ", . __ I )._ ,_ ;, / I I '.. ,. I I - -_ , ; 11 , . . .. . .. . .. . ........ ; I .f." "F ":; ' , lT)p -e, , " " "' , -1 1 ,: _ I.. :, I : ----',.,-, , " T , ,__ C ; I1 0 M; ii , 11 y l , - .11,11, , . . L PDL1, .. ',' .1 I . , , . 11 I . , . " ... 1, 11.- , I - I : , " 1, - '. / , 11 '..; 1iII t"...e,,I ,'L1. . : : I " ; II.I.,.0I ;,_ I"0 /AND W5T 4 _- , . -1 , :,. , i/ I , ; ;I , 11 I", . . , 1: . j . ..... ............... ..... 11 I - /- 'N: , : , : - . "v- .1 . I I ' ,,;,.,. = . 1. . 1, I SEE DRAWINGS G3 I . .- : , : ", <_1 \ . I _:. T - _. , " ,., , , / I ; . I ,- , " I i` -, , : . '. 11 i I .', I I " - p - / .1 11 ", , . . I,.` - " ", D", -- 3 " -, N - 0 - - /_ . / ,/ '_; , I /) f, / 11Lu "/-"-,,-/ I " "//, 1, 1 -_11. ,",'4" - . , ,, , I, I.,I ",,:j ;=2,,5,I':'. L i,,'11'IIL,.,, l:,;: . ", ." , ,)Ir,, e-c'. 1/I . 1........., "" 11 1,I !rI ;: II_,L''I II ---- V' rC,.,; 11 11 , " "I", I ... 1 1, . I ,>; 11 , , I 11 l_'yl L ' ' I . " - 1 . I , / I / " -- , " 11 " 11 "; , \ I / .' L ')"'\ *,p I11 " .. `_ , rl I , ; !,.4 ., , " r, , -I ,L ; l/ , .; _` A,,.-__.-_- 1 , IA. S N I " I " L.,_ _N" r * , ,- ;;,Vl j" ! li1I . , N -- 1- , - E -I ., , ,-, I , L I I I - - - ........... f" , , - ,, ,<.::,%- l . - ", p, :" % .... %_j' i-, , v / "' L, ; --.,,, AND G4. 1-1I /111 4 : 1\11 " : , o;,, , )-;'6!"`4 ,: . - I - rI . : ... :. ; ! , _t' , : I_. " . `"" X* II.':.:: F / I ; - ' .. . , ,_ " . 6'CONSTR.U/O t, ' 2. V b 11 : , : " . ,,L , , _l 7 , : " -:z , A W1 - Y"'" 1YL,'` .. 1 _____-_--, .,,,,".,:"...,,.,.,, !, ..- ... ;/: -1 -,;` ?! 7 9/ / /, "':V..- x i / / /\ / / z, , ,0 ' " . , ....",* ..... ---- ..............:_......................................................... I ........ ..... ......... 1, I cl, ,, 1:11N -% : ,.;" ..". I . I1, -/ 1... l11 li, ,-,\, FENCE /%t3. FOR GENERAL DEMOLITION z 11 ''I -\I , LIi , "t'."": ' * " .. - , , 11 I ., 115 '.. ,., I '11-11 ,, <-) , ,.?, , .. .1 I ; IV' ,,, i.- ... f 1',\ , ,, ,14 / - 7. on - ,Q ., I 1, , , //lv OF A ' - : jl,, .1 I / 1/L, rl / / /, ,-. , , b 11 "I" " ,,,.,, / .. 11 ! 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I I I - " I ; 1, :" : .1 11 : : - : I— : : 1_1 V///// 8 50 -1 I li., " ;.y I 1-l" . \ I : , I : : : 4___ ; . 11 :, N 71, 850 I . . , : I : . e: . : m - ! . 11, I i ; AR UNDE i 1- i - I I ; r Om'TRU I C"T/ N ............. 2 iO' 1 O' 0 2 10' 40' mllllllllllllllllllll1111111111111111111111illillillillillIlIlIlllill ilillillillill illillilillillillillinflillillilillillil --- - I S. I /2, SEC. 24, T. 23N., R. 4E, W.M. N N. 1/ 2, SEC. 25, T. 23N. j R. Cl wome r PERMIT SET DATE: 07.27.98 L 11111111111111111111111111111111111 I 0_"!F!t,7 e.-Vitll,c—,!ro--,.--;- m iffi' V - 7 pillN MO11N 0 7, ro VZONO LIJI 111mmarl 1- 11, 11Hm illLil11211L 1111 1111111 7Tit,m-1. i-, w_MQM IM K. ( 01IIIIIIIIIII15mKill - 1 E•;gym•1Im r I=; I m®® m® KEY PLAN ' SCALE: NONEse- 9 - I:)_ 4 1. DWG 9L27 00 cr) 0 CN4 N DEVELOPMENT 13L CITY OF RE14I LL' AUG 0 ry z: n 1998 MNING ON N 71,800 z W zmoo Ldon z n0 3 (DoC4) (g) Moc)o LL- LLJ L3v) 0 Lu Ljj t0c) 9)< 0 N3 C) Lo ct" Li 7 o 0 (D LLJ N_j 0 IL C) 5V) Ld 3. 0 0 L Z LLJ LLJ z 01, L M ry 0 Q- O E--4 LLJ E--4 7-) nj0-4 c C) Eo o EQ) E N c C z z x 0 V) z N 71,60 2 LL- M J Ld Ldwx 0 0 0 0 0 f) 0 jl n- x 0 CD C14 0 0 o LU hi REMOVE 4" ACACIAi x REMOVE 16:4f, I-x 7:1 4 jlrf 8. 5 17\ 0 f .................... . . ...... ---------- .... . ........... PROPOSED :! STORM DRAINAGE COMBINED WETPOND/ DETENTION POND DESIGN SURFACE EL=8.5 — 000, X/ C, /Y i//// 0 NOTES: 0 L"/ 1. FOR SURVEY CONTROL LLJx INFORMATION, SEE q x xDRAWING G4. x xxXx, PR( P0 E D /E N 6 RG/E M /EN T /0F /C S /TC zlxxx , XX 2. FOR GENERAL DRAWING bETZNTj6N /PONO AQ/WFTLAKQ_,. x NOTES AND SYMBOLS, X DESfNU755SEEDRAWINGSG31, 1 =8 x - ANDG4. XN 71, 800 N N3. FOR GENERAL DEMOLITION N x xx x ANDTEMPORARYEROSION/' M W-141 MKl401 N12,339 9 1 70 SEDIMENTATION CONTROLNOTES, SEE DRAWING N N 9L801. N N NEXISTINGSTORMDRAINAET/ ANC/"B/' ED K UAA TO BE PROTECTED AND TO REMAIN. N 0 0 cq Lo LLJREMOVE / 8"/, ACA CONTRACTOR STAGING, IA/ LAYDOWN AND STORA(1-1-- N AREA. CONTRACTOR SHALL X PREVENTTRANSPORT OF x X X SEDIMENT TO EXISTINGX 1-: Ji/ .... ..... x DRAINAGE SYSTEMSIN N\ ACCORDANCE WITH SPECIFI--- x CATION 02710. x 1 ... ... . ...... x x x X\ x y x xxxxxx x NRiMOVE /AGACx NXxxxNxxxxx x xxxXXxxx x x xxxXXxxXPROPOSEDx x x N 48" CULVERT " xx mmNNNPROPOSED 8" N N IRRIGATION MAIN x ' x NN N N x xN xPROPOSEDMW-4X' UNDER DRAIN x N' 71 , EL. 15.44600 2 N N N NN V, WETLAN BOUNDARY7—6' CONSTRUCTION FENCE Ln LLJ 2.0' 10' 0 2. 0' 40' S. 1/2j SEC. 24, T. 23N., K 4E, W.M. N. 1/2, SEC. 25, T. 23N., K 4E, W.M. r =I PERMIT SET DATE: 07. 27.98L I mp Aw Wil mSOUP L l l Lill ll l' Bill'sIIa 111 1 031 mmW111 KEY PLAN SCALE: NONE S, f - 9 W z 0 a Z m0 V) N V) Y w a wLa tLw x 00 rn 06 04 O 00 CITY OF RENT vAUG 18 19 w ... .a•, Q/- z LL Q Z l 1— 0— woNo o 00 LL w ULL O W uj Q CN0 q) O iN NWlL QO 0m u z CDzW OQ 3: CD mUzw Z w U ow w Q 0 O m ry J IN> U r E v Q r 1 W vw a v' v vE au m E C N I C v 0 La- 01A a z9 b z O V) gY U V a x m Uy 3 oY Y 08 a a a_ LJ 0 z O ry O z J o o . N f in w ... - jj i- i Lj iNG t . ilk •`• !, N 71 ,800: N 71,800 AREA UNDE I 'i coNsrRucrioiv PROPOSED 8" A / IRRIGATION MAIN D r_................. G RIV BUILDING 25-20G WETLAN d/ // BOUNDARY 6' CONSTRUCTION - ENCE i F t CLEARING LIMIT i Q /, ;? FENCE TYP) O ' i W/ // DEMOLITION LIMIT i I i ii ............ i" 6 xxx/ XX 6MY/1 IF P POSED s, RO T _GWELANDH' IUNDERDRAINBOUNDARY A- r i X- r T AND H Y - i r.......(....... .. ....:.... .................... . O J LJO W TRAILER 1 72 A L R AREA AREA I JI DER NSTRU rION 1• 1 i tl i V. a r....- 1 t( ILER Ir1 Q 1j 0 I t O I IA i i in LLJ 20' 10' 0 20' 40' S. 1 /2, SEC. 24, T. 23N., K 4E., W.M. N N. 1 /2, SEC. 25, T. 23N.9 R. 4E., W.M. PERMIT SET DATE: 07. 2 7. 9 8 X5100042,DWG 9L2F NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION / SEDIMENTATION CONTROL NOTES, SEE DRAWING 9L801. HELISTOP FACILITY (BY OTHERS) IS CURRENTLY IN DESIGN/PERMIT PROCESS. CONSTRUCTION IS PLANNED FOR SEPT 1998. HELISTOP FACILITY IS TO BE PROTECTED AND TO REMAIN. 5 EXISTING CONSTRUCTIO'] TRAILERS TO BE REMOVED BY OTHERS. FOR DEMOLITION OF STORM DRAIN, SEE DRAWING 1 C(D)28 FIRE HYDRANTS TO BEEDPROTECTEDANDTO REMAIN. KEY PLAN SCALE: NONE d N NW W aN w aW Ga W UN FOJa W Ww x 0 0) N R i i LANNINGDEVELOPNi _. CITY OF RE NT _ DLiAUG18199 $ z QED w Lv I__ n o c) z coow a,03 LL U y3 LLJ N o Q N rrQ 0omU z OzW J O N 71 ,4C LU zw w UQZ ma W 0 mLry/ L.L J D Do > cn U N'c OY E- 4- 4 a 1 -i WEEE W a a o 5Em E Q'NC 0 L a n. m J a a a F- 0 z 0 w O z N 71,20 a- m co Q a N . w _ QZ-0 ly • 7 ,. NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. r 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GENERAL DEMOLITION Q , AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 6 CONSTRUCTION 9 L80 1. FENCE EXTENT OF 12 SSr / / / / I '•, UNKNOWN. CONTRACTOR f' TO REMOVE ALL 12" x / / MW1143 SEWER SYSTEM WHITHIN j / / / / . , \ LIMITS OF DEMOLITION, t N 71,400 PLUG AT LIMITS, ANDjRECORDPLUGLOCATIONS. I........._... _. -...... Q I i iF 1 fib,,_.... -• j 'Cti oc t , r I f { ? r co 1 i Q PROPOSED 8' j I f IRRIGATION MAIN i r.------ ..-... I I I 1 WETLAND H ` I PROPOSED STORM, DRAINAGE COMBINED / / / / / / / / / ?` `, BOUNDARY _ WETLAND DETENTION POND DESIGN SURFACE EL=8.5 MW-45 4904 E 51 1,8169/ rl M RIP -RAF PROPOSED L D „ 0 ED`• WET AN I„ o UNDERDRAIN BOU46ARY ,. Q P i I f 6' PROPOS--ED '.`24 STORM DRAY REMOVE .\;, 17" ACACIA,... . sl o RI - ,13.61 o / / / / / / / / / / o IE 24' PGP (E) = 8.97co :} o IE 24" CMP ,(STAN© PIPE) = 3\33 BOT 8" BAFFLE = 6.26 AREA IS THE SITE OF 5 A PREVIOUSLY DE- MOLISHED RESIDENCE. RESIDENCE FOUNDATION, PAVEMENT AND SWIMMING POOL TO REMAIN. REMOVE I ALL REMAINING CONCRETE, UTILITIES AND DEBRIS. 18" DUCT IRON ;.. wr :°r:Y• '>•::":;:; IE (W) = 6.09 FOR DEMOLITION OF 24 STORM DRAIN, SEE DRAWING 1C(D)32 RIP —RAP 'y EXTENT OF 3" W UNKNOWN. CONTRACTOR TO REMOVE ALL 3" j WATER SYSTEM WHITHIN I LIMITS OF DEMOLITION, I ' PLUG AT LIMITS, AND RECORD PLUG LOCATIONS. I CONTRACTOR STAGING, LAYDOWN AND STORAGE AREA. CONTRACTOR SHALL PREVENT TRANSP`_)RT OF POND SEDIMENT TO EXISTING WATER EL = 6.9 i DRAINAGE SYSTEMS IN 11:47AM, 719198 ACCORDANCE WITH SPECIFI— CATION 02710. 24" RCP IE (S) = 6.1 20' 10' 0 20' 40' S.1 /2j SEC. 249 T. 23N., R. 4E., W. I. N N. 1 /2, SEC. 25, T. 23N., R. Co W. I. PERMIT SET L— _DAB 07.27.98 J N" IN III 10/101 I" L11111 If'11 Ei i E • ,'ll", i 1 III Q'! Iml- MIRE Ell ff-mm gym KEY PLAN SCALE: NONE p--6) , - /:-7 W DEVELOPMENT PL3 , CITY OF RENT 1 WAUG 1819E Q 3 Z o W Z Ld I- n z z O o o L w5 1 Ito V I 00 a Q 1 N Q DmU o' O z w . IL CD N WL U 16z w w U ua Z w 0 Q Q L WJ 1 : : ( V U w o 0 0 0 O o a U v W da Fw- 0 Q' 0 a m E E Q' N Ccc:: Q1 O o a U U a m J O CL a a w Q W x m 0 0 z O O O N O j j Ln ry x 0 O N N N O O 0 O O O L0 w i i aG W Q r i O O Q0 rq T) n F V- I t x CLEARING LIMIT I 'gym i FENCE ( TYP) r I cornINrinFC WITH I I I v u- ] h' r NK NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 9L801. HELISTOP FACILITY (BY OTHERS) IS CURRENTL_'r IN DESIGN/PERMIT PROCESS. CONSTRUCTION IS PLANNED FOR SEPT 1998. HELISTOP FACILITY IS TO BE PROTECTED AND TO REMAIN. FOR DEMOLITION OF ED24" STORM DRAIN, SEE DRAWING 1C(D)33. 6 EXISTING STORM DRAIN- AGE SYSTEM TO BE PROTECTED AND TO REMAif` EXISTING ELECTRICAL EDSYSTEMTOBEPROTECTED AND TO REMANI, 1 5 10 15 1 17 18 2 21 22 23 5 27 8 3 0 6 7 3 3 jr 20' 10' 0 20' 40' 1 O 0 4 45 4 50 5 3 z 55 S. 1 2, SEC. 24, T. 23N., K 4E., W.M. 5 60 N N. 1/2, SEC. 25, T. 23N., K 4E., W.M. 1 6 63 64 65 7 68 6 7 w PERMIT 71 72 73 7 75 SET KEY PLAN SCALE: NONE DATE: 07.27.98 T1 Wwx 00 LL: 0 0 z 0 EVELOPMEN I CITY OF RENT DI 4 u AU G 181998 LLJ ry cl- n LJ I__ n 110p000 LL_ q) 00") LL_ C14 0 L-Li LLJ Lot 0 u < Q o.2 Ln LJ Z C:l8 < CDm.. u 0 o LLJ 0 j < J N 71,40b 00 zw w Lcozu< r.) L M0 ry LL_ cn 0 0 W E 0E- 4 E- 4 -0 :3 n a- C c: E Q) E E N C c 0 Q) z? z zx 0 i ui T 6o wz ID, 0V) m_ j UZI" O cr_ a_ n LLJ 0 0 U) ry 0 z 0 0 0 n X5100113. DWG 9L34 000c_ 0 0 0 0 L 0 CD 10 0 0 0C. llloo, 000c. 000(. ')o 0 0 0 C. 41 In10000c. NOTES: V) 00 00 c l: 1 0 0 0 O1L oorl l000r- -00r, L. LJ 1. FOR SURVEY CONTROL LL) 0 0 0 0 r- 10000c loorl, 106of- l000( 10000c. INFORMATION, SEE 0 000(_ OOOL 100006 10000 10000c, 10000c looel 1000of loorl, DRAWING G5. looll, cn 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, STABILIZED. SEE DRAWINGS G4 x CONSTRUCTION AND G5. Ld ENTRANCE 9 3 4@9 3 L1 L 023. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ A SEDIMENTATIONCONTROL j NOTES, SEE DRAWING 0 V) 4 91_801. 0 c' EXISTING KING COUNTY n ED SEWER TO BE PRO— LLJ TECTED AND TO REMAIN. CLEARING LIMIT 0 I' can FENCE '( TYP) EXISTING PUGET SOUNP_ COINCIDES WITH N 7 1,400 ENERGY OVERHEAD En DEMOLITION LIMIT POWER SYSTEM TO BE PROTECTED AN TO REMAIN. cn V) KING jC0UNlY CONSTRUCTION HAUL hi SEWER EASEMElIT ROUTES NOT SHOWN. CONTRACTOR SHALL PREVENT TRANSPORT OF SEDIMENT x AND DEBRIS BEYOND PROJEC 5 LIMITS IN ACCORDANCE WITH u' SPECIFICATION 02710. Z 0 F to Ln zt N 0 V ETAT 10 NAREA U x 0 CITY OF RENTON RIGHT OF WAY LLJ 0 m LLJ 0 PROPOSED; UN: DERbRAIN, Lj U z c):f 0 co W s 1/ 2l SEC. 24, T. 23N., R. Cl W.M. N. 1/ 2, SEC. 25, T. 23N., R. Co W.M. r _ _ _ _ _ _ _ _ I PERMIT SETDATE: 07. 27.98 L J[ 00 ANN;, 11 Millllr WIN I m9l L i1 Illlil l c; ar i; AIi lw- 001 L IS ff " , r m Rl r, gym KEY PLAN SCALE: NONE X51 0011 V) Ld tJ V) wtAj 01JI- 4/ "Il., Ln Ld Lb 70 N LDEVELOPMENTP- "ANINIG 7 vCITYOFRENTON AUr, IF 1!19BC) . ... . ... LLJV 0 EDn IX LLJ LLJ X PROP IXLID0— X Avo L_ UJ STORM,\,,DRAII oo 0)0)00 LL_ LREPLAC ENT 0 Lu ............... 04 LJLJ ...... Lr) > ot 0 000 o; cn zLij CLEARING LIMIT c\l7jj < FENCE (TYP) I . . . . . CD o LLJ 0 N 71,400 0 AND L z ETL0LLJLLJ N DARYZqclB % x Lm . ........ N H 4 0 A Q) 0 4n CQ pE- 3--o uJ E-4 c 0)0 c E0L. Q) m:3 E IE I, E ito C 0) s00 4 0x z 3: m 0 V) w U) L) IL m t x TO REMAIN a X pp 18 N. l q x- f P a d] x V. ET LA' D K B U NOUN RY L. . ....... . ..... ....... 1- ......... . ........... . ......... x 7 J x X N 7 .......... N 71,200 ...... x loo 0 co NOTES: Ln Lu 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 91-801. EXISTING STORM DRAIN - ID AGE SYSTEMS TO BE PROTECTED AND TO REMAIN. CONSTRUCTION HAUL N 71,400 ROUTES NOT SHOWN. CONTRACTOR SHALL PREVENT TRANSPORT OF SEDIMENT AND DEBRIS BEYOND PROJEC-T LIMITS IN ACCORDANCE WITH SPECIFICATION 02710. I % k I ; i t . 4) . ...... . ...... . ....... . ....... . ....... m x 0; 0 LQ Ld Al. z 0 n fy j 1,200 I LLJ 210' 10' 0 2.0' 40' vlL__lmL_mmL_jm_j M MOM S. I /2, SEC. 24, T. 23N., R. 4E, W.M. N. 1/2l SPEC's 259 T 23N., k 4E, W.Me CONTRACTOR SHALL MINIMIZE DISTURBANCE AND REMOVAL OF EXISTING VEGETATION IN AREA OF FORMER PRACTICE TRACK INFIELD. MEN! l O lmm l_ Affj- act- molmi 4.. I' II'1 11fS 1_ elHmEl S riMNS', Lkl I'M olow, Ea RISEN Ell r_;m gym 0 z KEY PLANPERMITSETF —1 SCALE: NONE DATE: 07.27.98 9 L3 7 W 0 z m0 LL: Wwx co 000 C14 0 DEVELOPME V i CITY OF REN 1;'C i 93u8 Li 0 .......... ... uj U 0- moo U- w LL 0 0, C 00 0 00 0 wwr." 04 Ho 000 4) cn < LLJ Z Cnoto I o 0 :E CD zry 0 0 j < 0 LuL L-LzEj- clwe < L m 01,ry 0 0 3' TALL CONCRETE W, 0 Q- 1) 0 41 E- 4 u n c E E coE c: N Q) L_ 0 z 0 z 0ZZZ n. R. z 0 f) w 1.... ... ....... 71,000 x i NOTES: D ( D 0 1. FOR SURVEY CONTROL Ln wINFORMATION, SEE DRAWING G4. j, PROPOSEDLAKE .............. . ............ . . .......... ..... . . .......... .. 2. FOR GENERAL DRAWING AERATION/ RECIRCULATION PROPOSEDSTORMNOTES AND SYMBOLS, WETLANDDRAINAGE COMBINED SYSTEM BOUNDARYSEE DRAWINGS G3 WETPOND/ DETENTION POND AND G4. DESIGN SURFACE EL=8.5 6 CONSTRU CTION FENCE 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ A SEDIMENTATION CONTROL REMOVEALLTREESWITHINNOTE S, SEE DRAWING DEMOLITIONLIMIT (TYP) 9L801. CONTRACTOR STAGING, LAYDOWN AND STORAGE' UL VTR T AREA. CONTRACTOR SHALL IIE9P /SW)/= 1 81 0 PREVENT TRANSPORT OF SEDIMENT TO EXISTING 00 ...... DRAINAGE SYSTEMS IN ACCORDANCE WITH SPECIFI 00 CATION 02710. MW 4 EL. &;" 559<-A-,1, Z CULVERT GPGIE 12 CMP (NE) 10.68 K C ...... ZL STABUEDCULVERT CONSTRUCTION 1E 12" CMP (SW) 10.96 CM ( N 11.13 ENTRANCE ..! . ........ 1E I N Z' CULVERT9 @379L I 379L021E 12 PVC (SW)= 12.31 N N 71,000 N vow l0000( 0 0 '0006 ....... 000c. 10000c. 0 0 O IL 00001L00" w oc. 0 ' 0000C'0" gooloon ZLLJ Lj ct- N 70, 800 I I \ % a I w _; L_ Lj _r CULVERT SILT FENCE/ CLEARING LIMIT FENCE ( TYP) 8" IRR DIP COINCIDES WITH DEMOLITION LIMIT M 9 37 0 X X x x x xxx Li J j01) o 0000000000, 0, IJ o 0 0 00000000p00, 0 .......... 0 0 0000 LIJ, 0000 0, r STABILIZED CONSTRUCTION ENTRANCE 3709L 02 x x N 70, 800 2.0' 10' 0 2.0' 40' S. I / 2, SEC. 24, 1 23N.j R. 4E, W. I. N. 1/ 29 SEC. 25, T. 23N.l R. 4E, W.M. r I PERMIT SETDATE: 07. 27.98 L 0zKEY PLAN SCALE: NONE 9 P_ 9 11.3 -1 -07-T 00 rn 0000 ' Jr 0 Y DEVELOPIIviLi o CITY OF R vw AUG 1 V1 WC7 o z w F-- 0 z 00 Cc) ID Uz Lw0 Uo O Li 3Lno^Wz LL1 00 comItU:>: f O O zw OQ IL CD r O3: 0 zw W Lii a ZwU Q L O x M ry Do> u U w 0 L ao WodD 0 Q Y I LijrT, W NN w L0 a a as m i= E 1111 O'N CA 017` 1O: Z 9\ z WN d' S OZ NWI V /) 0 O S wz} Q N N V l V a am J V 03 oY Y o V WWO V ry a o_ a w Q w xxm 6 o o o ry x 0 O N N N O O 0 w O J EXISTING ROAD TO BE REMOVED BY OTHERS AN 9'. N 71,000 `^ WETLAND „ I„ B NDARY —/ UE- MULII IVIV L 2 3 99L 02 0 0 N X X w REMOVE ALL TREES WITHIN DEMOLITION LIMITS (TYP) 1 m \. GAP X \ Q N 71,000 PROPOSED UNDERDRAIN I vOvO O O C 1 0 0 0' `0 000^ 0 V y STABILIZED ,... - i CLEARING LIMIT FENCE ( TYP) lf COINCIDES WITH DEMOLITION LIMIT r i 6' CONSTRUCTION FENCE 0 0 Q0 Ln w ter. , il... S.:.i 20' 10' 0 20' 40' S. 1 /2, SEC. 24, T. 23N., R. 4E., W.M. N N. 1/2, SEC. 25, T. 23N., R. 4E.9 W.I. PERMIT SET DATE: 07.27.98 1 X K QL38 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 9L801 . DHELISTOP FACILITY (BY OTHERS) IS CURRENTLY IN DESIGN/PERMIT PROCESS. CONSTRUCTION IS PLANNED FOR SEPT 1998. HELISTOP FACILITY IS TO BE PROTECTED AND TO REMAIN. 5 EXISTING ELECTRICAL AND COMMUNICATIONS SYSTEMS TO BE PRO— TECTED AND TO REMAIN. CONSTRUCTION HAUL ROUTES NOT SHOWN. CONTRACTOR SHALL PREVENT TRANSPORT OF SEDIMENT AND DEBRIS BEYOND PROJECT LIMITS IN ACCORDANCE WITH SPECIFICATION 02710. El KEY PLAN SCALE: NONE s 0 -6) 8- I ?-_ -_ J DEVELC CIT . w AUG W Q ryLL_ CL 0— Z o gooIt U 5 Cj_ co 0 Ii wz w U 3 O Lij a Q LLJ 0m-U:i Q 0 Z O z w N O O Li 0 Z zw Q w a w 0 C a:® m U L a n, 0 O 0 00 H Q J W w a v a L E C'NC j I C phi wwx 0 0 0 Ln X 0 0 N N N 0 0 0 w J rSa 2) Qs Z 3 O a a Q W H Q 0 Z 0 V) O Z 2 0' 10' 0 2 0' 40' S. 1 /2, SEC. 24, T. 23N., R. 4E.1 W.I. N N. 1 /2, SEC. 25,123N., R. 4E., W.M. 75RM lTj=E7 DATE: 0 7.2 7.9 8 L39 NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G3 AND G4. 3. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 9L801. EXISTING KING COUNTY SEWER TO BE PRO— TECTED AND TO REMAIN. EXISTING PUGET SOUND ENERGY OVERHEAD POWER SYSTEM TO BE PROTECTED AN TO REMAIN. CONSTRUCTION HAUL ROUTES NOT SHOWN. CONTRACTOR SHALL PREVENT TRANSPORT OF SEDIMENT ND DEBRIS BEYOND PROJEC IMITS IN ACCORDANCE WITH SPECIFICATION 02.710. 7 EXISTING STORM DRAIN AGE SYSTEM TO BE ROTECTED AND TO REMAIN. lm lamI m m KEY PLAN SCALE: NONE JY 6 U w ix 9 H N N W aN w aW a 0Ja WW X V r) a-- O O Ln x j 00 0 i 0 Ln j DEVELL, CITY C AUG a. ry ry 0 0 z0 Ld i 1* LLJ U z 04)000 c4) z LLj 0 00 C, 1 4 V) 0 LLJ LLJLo 00 .,t L0D 0 o.? to z ct,4 LLJ C 3 c) o m Qf 0 c) LLJz 0r__ V) V) IL j < C) CD wL0Z z og - J- L.m 0 ry v) so V) 4) 0 00 D a, cc E aJ m:3 E E CN CE 0m) 2 z0 z 3: 0 TZ j V) 0 wy 16 Q. m m j Q_ LLI wwX m 0 C6 0 0 0 x I-" 0 c\j 0 0 0 Lij 0 t+ 70,800 i o ! ED 11; 81111 1/ olLLJ VPROPOSE[ STORM UNDERDRAIN, VWETLAND 'Y' all BOUNDARYA-5 4) CLEARING . ... FENCE (TYP) In .... ..... 1b, j- j 4_ OF 16 ...... 4 -------- .. .. . ... 16.4 ..................... ........ X 16 ........ 15 . ..... - - ---- .... .. 14 - - ----- 13 0 0 Ln 0 o0N '0,800 Ln Ln Li LIJ OHP tl <% N 70,600 e, IN 1 0 0 L0 Li 0 0 oq t Ln Ld 20' 10' 0 2.0' 40' S. 1/2, REV. 24, T. 23N., R. 4E, W.M. N. 1/2l SEC. 251 T. 193N., R. 4EI wome IPERMITSET DATE: 07.27.98 9L45 GENERAL NOTES: 1. FOR SURVEY CONTROL INFORMATION, SEE DRAWING G4. 2. FOR GENERAL DRAWING NOTES AND S'\I/MBOLS, SEE DRAWING(., G3 AND G4. 3, FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 91-801. EXISTING OVERHEADEDPOWERSYSTEMTO BE PROTECTED AND TO REMAIN, aD CONTRACTOR SHALL MINIMIZE DISTURBANCE AND REMOVAL OF EXISTING VEGETATION IN.AREAOF FORMER PRACTICE TRACK INFIELD. NMI 1! 55 60® I KEY PLAN SCALE: NONE Y 00 o r7 0 a G: (L i o DEVELOPMENT PL o ITY OF RENT AUG 18 19ry N O'a W Q N fl LLLL w Z w nU o Z a o o0 Z W UL'- o C! ) O3 OD Ld to - a o ' Q z oQ — Q Zry ry O LLJ On IL Q O L Z c.) a W U O Q m ryaJ cn U V) Qo O O 0E Q J W W a Y a C cpo o E O a L mE E C N O N 70,600 U C d m J c3 Y c19• Y i ry I Q w Q W X m 0 0 r; z 00 O_ ry x O O N I N i N O O d- O w O t cp l i i l l , w Q I TON; y I' SEWER EASEMENT i I a 1 STORM UNdERDRAINMEW, le WETLAND\'k BOUNDARY \ 0 0 N 1 w 20' 10' 0 20' 40' S. 1 /2l SEC. 24, T. 23N., R. Cl W.I. N N. 1/2, SEC. 25, T. 23N., R. 4E., W.I. rm PERMIT SET DATE: 07.27.98 J X510 Tr A FOR SURVEY CONTROL INFORMATION, SEE DRAWING G5. FOR GENERAL DRAWING NOTES AND SYMBOLS, SEE DRAWINGS G4 AND G5. FOR GENERAL DEMOLITION AND TEMPORARY EROSION/ SEDIMENTATION CONTROL NOTES, SEE DRAWING 9L801. EXISTING KING COUNTY SEWER TO BE PRO— TECTED AND TO REMAIN. EXISTING PUGET SOUND ENERGY OVERHEAD POWER SYSTEM TO BE PROTECTED AN TO REMAIN. CONSTRUCTION HAUL ROUTES NOT SHOWN. ONTRACTOR SHALL PREVENT RANSPORT OF SEDIMENT ND DEBRIS BEYOND PROJECT IMITS IN ACCORDANCE WITH PECIFICATION 02710. EMS FAIIIIIIIII-— ll llm I 1 t1TiFi NJ KEY PLAN SCALE: NONE P_ 9 's- i a- 25mOl BLDG. LEGEND UPLAND/BUFFER-(ELEV. 11.0+) VEGETATED WETLAND-(ELEV. 5.5-11.0) OPEN WATER-(ELEV. 2.0-5.5) WETLAND RESERVE AREA STORMWATER TREATMENT POND 1-111- WETLAND MITIGATION AREA NOTE: ALL AREAS DISTURBED BY CONSTRUCTION WILL BE PLANTED AS SHOWN, OR HYDROSEEDED (SEE EROSION CONTROL PLAN FOR HYDROSEEDED AREAS). 0 70' 140' 210' GRAPHIC SCALE DEVELOPMENT PLANNI a CITY OF RENTON AUG 18 1998 Pq,r.mvp.n BRUCE DEES& ASSOCIATES L—d.-A. A—W—f— - Ut.0..q, 9l. Pimrirg - "U.0- Fa m— N" REVISION BY APPROVED DATE SYM REVISION BY APPROVED DATE ACCEPTABILITY DR4WN JENSENSMHUMM DATE 07.13.98 SUBTITLE CURRENT REVISION SYMBOL DATE THIS DESIGN AND/ PLANE} SPF( IEE(:ATiON Ic APPR1VFfi EL 107-13 qR ANDSCAPE I 0 UPLAND MIN. 3LJ V , Ooop:::5 0 5 O VEGETATED WETLANC ELEV. 11.0 - 5.5 0 0 PFO h tPSSI a0s' (PFM) a0o OPEN WATER EV. 5.5 - 2.0 ELEV. 5.5 - 8.0) CROSS SECTION vaznc& scaz GRAPHIC 0 10' 209 30* SCALES:0 209 409 Go` HORIZONTAL SCALE ATED WETLANDS 1. 5.5 - 11.0) NE EMERGENT EV. 8.0 - 9.5 0 0 PAL. SCRUB SHRUB EL -:V. 9.5 — 1 NE FORESTED (PFO 1. 10.0 - 11.0 0 ccl O UPLAND BUFFER 100 c-ilc- cl -, ) 0 OlAC DEVLO1\11"ECITYOF 'TN AUG 18 1998 RE(—%, FINfr 25 20 15 10 5 0 BRUCE DEES& ASSOCIATES L., W-1. ,,,vhka,,.. Urb— D. 9b Plarinq • FacMm D-p W c s a..< at %a w sm MEO-aa REVISION BY APPROVED DATE SYM REVISION BY APPROVED DATE ACCEPTABILITY THIS DESIGN AND/OR SPECIFICATION IS APPROVED DRAWN S. JENSEN DATE 07. 13.98 SUBTITLE LANDSCAPE CROSS SECTION CURRENT REVISION SYMBOL DATE SYM P HU iMEL 47.13.98 SHEET GINEER TITLE SURFACE WATER MANAGEMENT PROJECT CIVIL MASTER LONCACRES OFFICE PARK APPROVED BY DEPT. I DATE CHECKED A. B.DEES 07.13.98 06 No 979121-00 COMP N0. APPROVE° APPROVED DWG NO. 25. YD- I IN NI':11II III :1i::Illil III!a11'd ID1i;i1"'Vi i! 11111:'11 k,o it Ii OEM A *]'1 U rJ FLOODPLAIN MAP (16, SEPA PRE -APPLICATION SUBMITT/ RFACE WATER MAN I PROJECT c,TFR i nr Z .. . . .................. 67 Ht l i __.__ ro cr- L L. 4 J All F, IHoHJ U-6 ic 7771 r----77 7,, A mm"" .... . .................................. LLJLLJzLLJa- 00 V ry x AM, oc O A EliY D o LIND AVENUE SW SPRINGBROOK F— LLJ Lij F— V) F— n ui CREEK L.. . ............ . ................ ... .............. .. . ............ . .. ................. . ....... ...... . ...... ............... . ................. . ....... WEST VALLEY HWY tj I UI LjU L w z z Q) moo30C) C: CO 0Q) 0) CO 00 Q) LO 0 Q) 0 60 m LLJ Q O 0 C) LLJ 0 Ld z g u w m o ov) O ZgJLLJ a oj L.Li LL- w0oLLJo A T- 0 aO DOO I r7- Sym V11 Q N X/ SQ y" BOEING CST C PROP,RTY SINE AMNgqlilill BOEING LONGACRES' OFFICE PARK (LOP) IA PPOPERTY LINEvillE. N-"Y!, II 4i . .... 7 ON a - ... ...... j H 74' ot bf i j, 1 cd zMA> f If PROPERTY OF CITY OF SEATTLE 0 150 300 600 GRAPHIC SCALE C bAR''---RIVER-, P IPE INE BOEING T! EllL., PROPERTY7 - - ------- .......... # 4 u BOUN-DAR FUTURE OAKESDALE AVENUE SW LINE PM-71-H-li . ............. ffli I TU .77 Air71117-L -IIT I I J ................................ r 2t . ... ........ m: E GT SBOEINGPR L ........ ........... . . ....... SOUTH fy; i - ...... — ........ . ........ ...... CSTC 1 1 ........... MAR S H`-' PROPERTY !, . . ....... BLDG ll,F-T .......... ... ... LINE 14"i i '. 2 0 jLn j tj .......... 425-01 - - ---- . ..... . N J- Ij L- ....... . ........ . .................. rCSTC .. ........ 0225 II7 10i W... IPA r_4C4 C4C4C4A IWA 00CK INA - WA vMorodrMNA , ON eeeee Air rQ 0CON0, A# F Ad#FAr r r eeeeeeeeeeeeeeeeeeeeeeeeee ANX&IFANA"MA '='W IVA 'WAIWA WNWANAvW * W ei!!i!iea i!ieie%%i®iei®o%i e® eeeeeeeeeeeeeeeeeeeeeeee ie eeeee ieieieie ee® e eieieieieieieieieieieieeeeieiei ieieieeeea®eeeieieieieieieieieieieieie eeeeee ee eeeeee e eeeee!e eeee0eeeeeeee eeeeeee eeeeeeeieeeeeeeee0eee eeee$e'eeOeeeeeeeee SUBTITLE CURRENT REVISION REVISION ACCEPTABILITY THIS DESIGN ANDIOR PROPOSED GRADING PLAN SPECIFICATION IS APPROVED I a AUG 18 1%'J-3 APPROVED BY MEW-M - I A mm JOB NO. Comp NO. 014002 R5100069 YWG NO. I '\ 1 ^, C 1 CD U 0 C) t 0 D BOEING LONGACRES OFFICE PARK25 1 SURFACE WATER MANAGEMENT PROJECT I I y-- ----. - SEPTEMBER 30, 1998 DESIGN DEVELOPMENT Is r NOT FOR CONSTRUCTION Scale in FeetBvmrdruk, 1_- - , r J 1 1 i 1 J Lff 8 f..._.` \ mot` I CIVIL, INC. 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A '•.` ``\ a • _f « :. "., 19-- L._.. sw. t9"_ .--.'.'..—___`_+.._V / t v" t l f '' J /.tlr J I i I sp_ tK,,/?, 7 v0L, 2 C CD DRAINAGE REPORT CD i FOR et ill:CONCEPTUAL DRAINAGE PLAN CD °* C.iwim) t 44 5 rr* hWWV1 Longacres Office Park et Renton, Washington C September, 1998 Prepared By: Sverdrup Civil, Inc. Bellevue,Washington Prepared For: g)LIA17E/Arlir' DEVELOPMENT PLAri,.iNG CITY OF RENTON SEP 3 0 1998 RECEIVED DRAINAGE REPORT FOR CONCEPTUAL DRAINAGE REPORT The Boeing Company Surface Water Management Project Longacres Office Park Renton,Washington REPORT CERTIFICATION data included in this reportpreparedThetechnicalinformationandwas by or under the direct supervision of the undersigned, whose seal as a registered professional engineer licensed to practice as such in the State of Washington is affixed below: 7 ..3A 1YegWAS w 1, , : 01;• rir f• 4• I3 22 9' 11 SS%TER EXPIRES 06/05/ 'do Jeffrey J. Schutt, P.E. Project Manager Surface Wa er Management Project-Drainage Reportfor Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\222 \wp\dmrpt01.doc i September 1998 DRAINAGE REPORT FOR CONCEPTUAL DRAINAGE PLAN The Boeing Company Surface Water Management Project it Longacres Office Park Renton,Washington TABLE OF CONTENTS SECTION PAGE Report Certification i Table of Contents ii List of Figures iv Ap endices iv I PR JECT OVERVIEW I-1 A. Purpose I-1 B. Introduction I-1 C. Project Datum I-2 II P' LIMINARY iCONDITIONS SUMMARY II-1 A. Discussion of Core Requirements II-1 1. Core Requirement#1 -Discharge at the Natural Location II-1 2. Core Requirement#2 - Off-Site Analysis II-1 3. Core Requirement#3 -Runoff Control II-2 4. Core Requirement#4- Conveyance Systems II-2 5. Core Requirement#5 -Temporary Erosion/Sedimentation Control II-3 B. Discussion of Special Requirements II-3 1. Special Requirement#1 - Critical Drainage Areas II-3 2. Special Requirement#2 - Compliance with an Existing Master rainage Plan II-3 3. Special Requirement#3 - Conditions Requiring Master Drainage Plan II-3 4. Special Requirement#4 -Adopted Basin or Community Plans 11-4 5. Special Requirement#5 - Special Water Quality Controls 11-4 6. Special Requirement#6 - Coalescing Plate Oil/Water Separators 11-4 7. Special Requirement#7 - Closed Depressions 11-4 8. Special Requirement#8 -Use of Lakes, Wetlands or Closed Depressions for Peak Rate Runoff Control II-5 9. Special Requirement#9 -Delineation of 100 Year Floodplain 11-5 4 ' Surface Wat•r Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil. Inc. 014002\2220\wp\dmrpt0l.doc ii September 1998 1 1 TABLE OF CONTENTS (continued) 10. Special Requirement#10-Flood Protection Facilities for Type 1 aInd 2 Streams II-6 11. Special Requirement#11 - Geotechnical Analysis and Report 11-6 12. Special Requirement#12 - Soils Analysis and Report II-7 i III OFF-SITE ANALYSIS III-1 A. Regional Overview III-1 1. Introduction III-1 2. Green River III-1 3. Springbrook Creek III-3 4. Black River III-4 , B. Task 1: Study Area Definition and Maps III-6 I C. Task 2: Resource Review III-7 D. Task 3: Field Inspection III-8 E. Drainage System Description and Problem Screening D1-8 F. Mitigation III-8 G. Previous Studies III-g IV RE 1TENTION/DETENTION ANALYSIS AND DESIGN IV-1 A. Existing Site Hydrology IV-1 1. Basin 3 -North Main Track Basin IV-1 2. Basin 4- South Main Track Basin IV-1 1 1 B. Developed Site Hydrology 1V-2 1. Basin A- CSTC Site Basin IV-2 2. Basin 131- South Main Track Basin IV-3 C. Hydrologic Analysis IV-3 1. Hydrograph Method IV-3 2. Compu ration Software IV-3 3. Design torm Precipitation Values IV-4 it 1 D. Retention/Detention System IV-4 1. Overview 1V-4 2. Hydrograph Routing IV-5 3. Summary of Hydrologic Analysis IV-6 I E. Water Quality System IV-6 V CONVEYANCE SYSTEM ANALYSIS AND DESIGN V-1 A. Proposed Conveyance System Overview V-1 B. Conveyance System Analysis and Design V-1 1. Uniform Flow Analysis Method V-1 2. Backwater Analysis Method V-1 3. System Materials V-1 Surface Wat r Management Proje It-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\222 1wp\drnrpt01.doc iii September 1998 I I TABLE OF CONTENTS (continued)II VI FLOODPLAIN AND GROUNDWATER INFORMATION VI-1 A. Baseline Floodplain Conditions VI-1 B. Existing Floodplain Conditions VI-2 C. Proposed Floodplain Conditions VI-2 D. Groundwater Influence VI-2 VII TEMPORARY EROSION/SEDIMENTATION CONTROL VII-1 A. Temporary Erosion/Sedimentation Control (TESC) Plan VII-1 B. NPDES Requirements VII-1 LIST OF FIGURES Figure 1 TIR Worksheet Page 1 Figure 2 TIR Worksheet Page 2 Figure 3 Location Map Figure 4 Vicinity Map APPENDICES APPENDIX A Floodplain Information APPENDIX B Existing Site Hydrology APPENDIX C Developed Site Hydrology APPENDIX D R,etention/Detention Calculations APPENDIX E Water Quality Evaluations APPENDIX F Water Quality Design APPENDIX G C1onveyance System Design APPENDIX H Groundwater Information APPENDIX I Temporary Erosion/Sedimentation Control (TESC) Surface Wad1er Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\227\wp\dmrpt0l.doc iv September 1998 P OJECT OVERVIEW Purpose This report is written to fulfill the requirements of the City of Renton Drainage Report for Conceptual Drainage Plan Content List. The City requires submittal of a drainage report with several of its permits, including the SEPA,Wetland, and Grade and Fill permits. 1. Introduction The Boeing Surface Water Management Project Site is located in the City of Renton, Washington, on the Boeing Longacres Office Park property. Longacres Office Park ("LOP") is a corporate office complex developed by The Boeing Company on the site of the former Longacres Park Racetrackin Renton, Washington. The 1994 EIS prepared by the City ofg Renton analyzed a preferred alternative Master Plan for LOP. This preferred alternative projected the construction of. approximately 15 buildings on the 164 acre site over 15-20 years. To date, property immediately north of the LOP site has been developed by Boeing for its Customer Services Training Center ("CSTC," 1993). Within the LOP campus itself, both the Boeing Commercial Airplane Group Headquarters Building and the Boeing-Renton Family Care Center (a day care facility for children of Boeing employees) are currently under construction. In addition an extension of Oakesdale Avenue SW, which will serve as a major access to LOP, is currently under construction by the City of Renton. The proposal includes enlargement of the existing CSTC wetland and detentio l pond, construction of a combined wetpond/detention pond and establishment of mitigation wetlands to compensate for wetland losses associated with LOP development. Later phases of the surface water management system will include installation of piping and other , infrastruIcture necessary for construction of individual buildings. The Technical Information . Report (TIR) Worksheets detailing site information and constraints to development are included as Figures 1 and 2. The site location and vicinity maps are detailed on Figures 3 and 4, respectively. All figures are located at the conclusion of the written portion lof the report, preceding the appendices. All tables are located in the appendices. This project is designed to integrate with the proposed Master Plan Development, the Drainage Report - BCAG Headquarters Building 25-20 Site Development, dated July, 1997, and the Drainage Report I— Boeing Family Center Building 25-10 Site Development, dated January 1998. Each of these documents were previously approved by the City of Renton. Surface W'ter Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. 014002\220\wp\dmrpt01.doc I-1 September 1998 C. Project Datum The current City of Renton vertical datum is NAVD 1988 according to the City's Drafting Standards. However, all previous mapping, design, reports and studies completed for the CSTC and Longacres Office Park Sites were based on NGVD 1929 Sea Level .datum, including the CSTC Site Development TIR, dated October, 1992, the Drainage Report - BCAG Headquarters Building 25-20 Site Development, dated July, 1997, and the Drainage Report — Boeing Family Center Building 25-10 Site Development, dated January 1998. Additionally, the Federal Emergency Management Agency (FEMA) continues to utilize the NGVD 1929 datum for their Flood Insurance Rate Maps. Boeing and the City reached an agreement at the Mapping and Survey Control Meeting held at the City's offices December 12, 1996 allowing projects at Longacres to be completed based on NGVD 1929 vertical datum as long as FEMA continues to utilize the NGVD 1929 datum. This Report is based on assumed NGVD 1929 vertical datum. The conversion equation is: NGVD 1929 =+3.21' NAVD 1988 I Surface Water Management Pro ect-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Ina. 014002\2220\wp\dmrpt0l.doc I-2 September 1998 it II LIMINARY CONDITIONS SUMMARY his Section includes a discussion of Core Requirements 1 - 5 and all Special requirements from the King County Surface Water Design Manual (KCSWDM) a referenced in the City of Renton Drainage Report Content List (from the City's rafting Standads). The City of Renton Building Regulations §4-22-8 formally a.opt the current version of the KCSWDM, and amend them to include additional c iteria for proj acts located within Zones 1 and 2 of the Aquifer Protection Area. he Aquifer rotection Area Map produced by RH2 Engineers, dated March 21, 1995, confirms that this project does not fall within the Aquifer Protection Area. Discussion of Core Requirements 1. Core Requirement#1 -Discharge at the Natural Location The existing project site drains to Springbrook Creek, as shown in Figure B.1, and will continue to do so under post-development conditions, as shown in Figure C.1. For the purpose of engineering analysis, the Longacres Office Park Site is divided into five drainage basins which all flow to Springbrook Creek. Under existing conditions, the project site falls within two drainage basins. The northern basin drains through the CSTC site outfall and the southern basin drains through the former practice track outfall. As indicated in the Site Master Plan, upon full site liuildout, .all surface water runoff from SW 16th Street south to SW 27th Street will be routed through the CSTC Main Pond and Delta system prior to discharge through the CSTC outfall (except eas east of Oakesdale Ave SW, which will discharge through the Practice Track outfall. This project proposes to enlarge the CSTC Main Pond and construct an upstream combined wetpond/detention pond to collect r sItormwater runoff from the site west of Oakesdale Ave SW. Discharge from the wetpond will flow through the CSTC Main Pond, Delta system, and ultimately through the CSTC outfall to Springbrook Creek. 2.Core Requirement#2 - Off-Site Analysis The Level 1 off-site analysis for this project includes the Boeing CSTC site to the north, Springbrook Creek, the Black River and tine Green River. A report entitled "Surface Water Management Off-Site Analysis Report," Sverdrup Civil, Inc., August 1998, was Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt0l.doc II-1 September 1998 previously submitted to the City of Renton for this project. See Section III of this Report for more detail. 3. Core Requirement#3 -Runoff Control a.Peak rate runoff control The existing CSTC Main Pond will be enlarged and a combined wetpond/detention pond (Pond "D") will be constructed to provide peak rate runoff control for the Longacres Office Park site. This includes the Headquarters Building 25-20 site since Pond "B", which currently provides peak rate runoff for the 25-20 site, will be filled in and eliminated by this project. Biofiltration This project is not required to provide biofiltration because it will not create more than 5,000 square feet of impervious surface subject to vehicular use and storage. However, since runoff from the 25-20 site will be redirected to Pond D", biofiltration will be required. According to City policy, when treatment pond volume and surface area exceed code requirements by a factor of 2, biofiltration is not required. Pond "D" will be sized to provide at least 2 times more surface area and volume than required by code to meet biofiltration requirements. Refer to Appendix F for more detail. c.Existing site conditions As defined within this Core Requirement, the existing site conditions are defined as those that existed prior to May 1979 since the specific project area never had an approved drainage system. Existing conditions are documented by aerial photography and field surveys. These sources indicate that existing conditions at this project site generally consisted of a horseracing track. 4.Core Requirement#4 - Conveyance Systems The proposed conveyance system consists of a small pipeline system and culverts designed to convey the on-site peak rate runoff for the 100-year 24-hour design storm. Some surcharging may ccur during 100-year 24-hour design events, while the 25-year Surface Water Management Prerect-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2220\wp\dmrpt0l.doc 1I-2 September 1998 2 -hour event will be conveyed without surcharge. See Section V o this Report for more detailed information. 5. Core Requirement#5 -Temporary Erosion/Sedimentation Control Engineered drainage plans are required for this project, hence, temporary erosion/sedimentation control (TESC) measures in accordance with Core Requirement #5 are also required. The 1 1 minimum 'requirements, KCSWDM Standard Plan Notes and tlje City of Renton Standard Plan Notes are addressed by the Erosion/Sedimentation Control Construction Drawings which were submitted as part of the Schematic Design Package dated August 26, 1998. For more detail, refer to the Schematic Design Package a d Section VII of this Report. t. Discussion of Special Requirements 1.Special Requirement#1 - Critical Drainage AreasP The project site does not lie within a designated criticalproposed drainage area as indicated within Reference 3 Critical Drainage Area Requirements of the KCSWDM, therefore this special requirement does not apply. 2. Special Requirement #2 - Compliance with an Existing MasterPqP Drainage Plan A conceptual site Master Plan was previously transmitted to the City of Renton. The draft plan included enlarging the existing CSTC Main Pond and constructing additional facilities south of the I! enlarged CSTC Main Pond for stormwater conveyance, treatment, and detention. This project is in compliance with the Draft Master Drainage Plan by enlarging the CSTC Main Pond to provide wetland areas and detention for existing and future stormwater runoff. The combined wetpond/detention pond south of the enlarged CSTC Main Pond will also be constructed as part of this project. 3. Special Requirement #3 - Conditions Requiring Master Drainage lan This special requirement does not apply, as the proposed project is stand-alone, and: i I Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Incl. 014002\22i0\wp\drnrpt01.doc II-3 September 1998 a.is not within a Master Planned Development (MPD) as described in an adopted Community Plan; OR b.is not a subdivision or Planned Unit Development (PUD) that will eventually have more than 100 single-family residential lots and encompass a contiguous drainage subbasin of more than 200 acres; OR c.is not a commercial development or Planned Unit Development (PUD) that will eventually construct more than 50 acres of impervious surface; OR d.will not clear an area of more than 500 acres within a us drainagea subbasin.g 4.Special Requirement#4-Adopted Basin or Community Plans No Adopted Basin or Community Plan exists for this area, therefore this special requirement does not apply. 1 5. Special Requirement#5 - Special Water Quality Controls Less than 1 acre of new impervious surface will be constructed for vehicular use and storage of chemicals, therefore this special requirement does not apply. I1i 6.Special Requirement#6- Coalescing Plate Oil/Water Separators This site will not be subject to petroleum storage or transfer or heavy equipment use, storage or maintenance, and the estimated traffic due to this project will be less than 2,500 vehicle trips per day, therefore, this special requirement does not apply. 7.Special Requirement#7 - Closed Depressions R.W. Beck and Associates reviewed the adjacent CSTC Site IDevelopment design for conformance with City and FEMA equirements in a technical memorandum dated September 11, 1992. Within Section III(B)2d of that memorandum, it was stated that "it should be noted that although Springbrook Creek does have a restricted outlet (due to the [Green River Management Agreement] GRMA), such restrictions have occurred so infrequently that [the site] should not be considered a closed depression." Springbrook Creek can reach flood elevations which temporarily restrict drainage from the site. These high water Surface Water Management Prject-Drainage Reportfor Conceptual Drainage Plan Sverdrup Civil, leo. 014002\2220\wp\dmrpt0l.doc 11-4 September 1998 I elevations on Springbrook Creek will be taken into account within conveyance system backwater analyses, which will be in the final drainage report. For more detailed information, see Section V(B)2 o this report. I 8. Special Requirement #8 - Use of Lakes, Wetlands or Closed Depressions for Peak Rate Runoff Control The CSTC Main Pond (also a wetland) will be enlarged along with tI a construction of a combined wetpond/detention pond (Pond D") south of the CSTC Pond to provide peak rate runoff control fdr the CSTC Building 25-01 site and the Headquaters Building 2 -20 site, including all future developments west of Oakesdale Avenue SW. Runoff from the BCAG Headquarters Building 25-20 site will be redirected from Pond"B"to Pond"D" for water quality treatment and water quantity control. Following construction of PInd "D", Pond `B" will no longer be required and will be filled Pond "D" will drain into the enlarged CSTC Main Pond for additional water quantity control. The enlarged CSTC Main Pond will continue to drain into the CSTC Delta area, as it does under elsting conditions. The CSTC Delta area is a constructed wetland area designed to accept stormwater flows from the upstream site. The Delta forms the downstream end of a linear stream system to be constructed as the development of the Longacres Office Park site progresses. 9. Special Requirement#9 -Delineation of 100 Year Floodplain This project site is in the vicinity of Springbrook Creek, which has a1 associated floodplain based on Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map Panel 53033C0978F. This project is outside the limits of the floodway but is within the flood fringe, or that portion of the plain outside the floodway Which is covered by flood waters during the base flood. The dEMA floodplain and compensatory storage determination are iscussed in Section VI of this Report and more detailed information about the floodplain, including mapping, is included in Appendix A. I I Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2210\wp\dmrpt01.doc II-5 September 1998 10. Special Requirement #10 - Flood Protection Facilities for Type 1 and 2 Streams No existing flood protection facilities exist for the portion of Springbrook Creek adjacent to the project, therefore this special requirement does not apply. 11. Special Requirement#11 -Geotechnical Analysis and Report A geotechnical report for this project was prepared. It is titled Report, Geotechnical Engineering and Hydrogeologic Services, CSTC Pond Excavation, Boeing Longacres Park, Renton Washington," dated April 23, 1998, and was completed by GeoEngineers, Inc. Other related geotechnical reports include: a.Geotechnical report, entitled "Report, Geotechnical Engineering Services, Boeing BCAG Family Center Building 25-10, Boeing Longacres Park, Renton Washington," dated October 3, 1997 by GeoEngineers, Inc. b. Geotechnical report, entitled "Geotechnical Engineering Services, Boeing BCAG Headquarters Building 25-20, Boeing Longacres Park, Renton, Washington", dated January 7, 1997 by GeoEngineers, Inc. c.Geotechnical report, entitled "Geotechnical Engineering Services, Boeing Customer Services Training Center Renton, Washington", dated February 11, 1992 by GeoEngineers, Inc. d.Addendum No. 1 Geotechnical Design Recommendations Lateral Pile Design and Buoyancy Clarification Boeing CSTC Development, Renton, Washington", dated March 25, 1992 by GeoEngineers, Inc. e.Addendum No. 2 Geotechnical Design Recommendations Lateral Pile Design (16 inch diameter) Boeing CSTC Development (UB 25-02, CB 25-03) Renton, Washington", dated March 27, 1992 by GeoEngineers,Inc. f.Report of Supplemental Geotechnical Engineering and Hydrogeological Services, Boeing Longacres Park, Renton, Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Ina. 014002\2220\wp\dmrpt01.doc II-6 September 1998 Washington for Boeing Support Services", dated December 9, 1991 by GeoEngineers, Inc. g.Geotechnical Consultation, Potential Lake Impacts, Boeing Longacres Park, Renton, Washington," dated April 29, 1991 by GeoEngineers, Inc. h. Geotechnical report, entitled "Geotechnical Engineering Services, Boeing Longacres Park, Renton, Washington", dated January 23, 1991 by GeoEngineers, Inc. 12. S ecial Requirement#12 - Soils Analysis and Report The existing mapping completed by King County in 1973 appears sufficient for the purposes of this project, therefore this special requirement does not apply. Surface WI ter Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\22 0\wp\dmrpt01.doc II-7 September 1998 III OFF-SITE ANALYSIS A. Regional Overview 1. Introduction There are two predominant waterways in the vicinity of the site. The Green River is the largest and is located in the City of Tukwila,Washington, about 1,200 feet west of Longacres and west of the West Valley Highway (State Highway Route 181). The Green River has a levee system along its banks protecting nearby property. The flow is partially regulated by the Corps of Engineers' Howard A. Hanson Reservoir near the headwaters of the River. Controlled flow releases, coupled with the levee system provides protection of the site from the Green River for at least a 100-year flood. In the vicinity of the project site, the West Valley Highway is higher than the levee system adjacent to the River providing additional flood protection. The second predominant waterway is Springbrook Creek (located to the east of the project site), a tributary of the Black River which is tributary to the Green River). All stormwater from the Project site flows easterly to Springbrook Creek. The project site is within the watershed of Springbrook Creek, and portions of the site are also within the floodplain of the Creek according to Federal Emergency Management Agency (FEMA) mapping. The stream channel for Springbrook Creek was previously reconstructed downstream of the SW 16th Street Bridge, near the project site, by an excavated channel, also known as the P-1 Channel. Currently, the City of Renton is constructing P-1 Channel improvements south of the SW 16th Street Bridge, to a point upstream of the future Oakesdale Avenue SW crossing location. 2.Green River The watershed area of the Green River above Renton is 450 square iles. Above the Howard A. Hanson Dam the watershed area is 215 square miles. The Green River flow is controlled by the Corps of Engineers, Seattle District, which is responsible for the regulation of dam outflows from the Howard A. Hanson Dam at Eagle Gorge on the upper Green River. The regulation limits the flow at Auburn to less than 12,000 cfs for up to a 500-year storm frequency. This flow rate represents a 2-year recurrence flood event if the stream was not regulated. The flood profiles for the Green River in the vicinity of the Longacres site indicate the same Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2220\wp\dmrpt0l.doc HI-1 September 1998 III flood elevation for both the 10-year and the 500-year flood frequency. FEMA flood profiles are presented in Appendix A. Flood profiles of the Green River with. and without levees generally indicate the same elevation of 23.2 feet in the vicinity of the Longacres Park site, opposite S. 158th Street (Longacres Way). Elevation 23.2 is significantly below the West Valley Highway I which is at approximately elevation 25 to 29 adjacent to the project site. Therefore, floodwater from the Green River will not enter the. site during a 500-year or lesser flood. On July 18, 1985, the Green River Management Agreement was entered into by King County and the.cities of Auburn, Kent, Renton, and Tukwila. This agreement was updated in 1992 and generally outlines and provides guidelines for improvements, nIonitoring, operations, and financial responsibilities. Important operating procedures are presented for the P-1 pump station, i cluding maximum pumping rates from Springbrook Creek/Black River as follows: Black River (P-1)Pumping Operations Limits Measured Green River Black River (P-1) Flows at Auburn Maximum Allowable Pumping Gage (cfs) cfs) Less than 9,000 cfs As required 9,000 cfs 2,945 cfs ( 1) 9,500 cfs 2,900 cfs 10,000 cfs 2,400 cfs 10,500 cfs 1,900 cfs 11,000 cfs 1,400 cfs 11,500 cfs 900 cfs 12,000 cfs See Note (2) Note 1: Assumes full installed capacity is available. Note 2: Maximum allowable pumping rate is 400 cfs to zero depending on levee monitoring by King County Director of Public Works or his designee. Further restrictions on P-1 pumping capacity may be required per the Pumping Operations Plan. Surface W ter Management Project-Drainage Reportfor Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\220\wp\dmrpt01.doc III-2 September 1998 I I 3. Springbrook Creek The confluence of Springbrook Creek with the Black River is established by FEMA as the upstream end of the P-1 storage bay of the Black River. This confluence point is 0.6 miles upstream of the Black River P-1 pumping station and 1 mile upstream of the confluence of the Black River with the Green River. The watershed area of Springbrook Creek is 21.9 square miles with the following peak discharges: Peak Discharges CFS at Confluence Design Storm Event Peak Discharge Rate (cfs) 10-year 590 50-year 930 100-year 1,100 500-year 1,550 In the area of the project site the 100-year flood elevation is indicated as 16.4 at SW 16th Street and 16.0 at SW 23rd Street. This is because the 1989 FEMA update for lower Springbrook Creek only extended up to SW 16th Street. The drop in flood elevation upstream of SW 16th Street is a discrepancy between the 1989 FEMA update and the previous study that was not resolved. The FEMA flood boundary map and the site contours as field mapped are shown in Appendix A. The flooding elevation of 16.4 is obtained by using the 875 cfs capacity of the P-1 pump station in loperation at the time of the FEMA study assuming no pumping restrictions from flooding on the Green River when a 100-year flood occurs on Springbrook Creek. The highest elevation occurs n the forebay when the flood flow is less than the peak of 1,110 cfs, during the downward leg of the hydrograph at a flow rate of approximately 785 cfs. This high water elevation in the forebay is 15.0. This elevation is used in a HEC-2 (Hydraulic Engineering Model for Floodway Water Surface Profiles) to generate upstream water levels to SW 16th Street. This results in an elevation of 16.42 at the SW 16th Street bridge. Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil. Inc. 014002\2220\wp\dmrpt01.doc III-3 September 1998 The FEMA data does not include provisions for the SW 16th Street Bridge with a 60-foot span compared to the old span of 36 feet. It also does not include the multi-barrel box culvert:under Grady WI ay, the box culvert constructed under I-405 or the completed P-1 jl Channel cross section from the mouth of Springbrook Creek up to tile SW 16th Street bridge. The City of Renton authorized R.W. Beck and Associates, Inc. to complete the "East Side Green River Watershed Project Hydraulic u Analysis Report," dated December 1996. This report recognizes conditions beyond those of the FEMA studies, such as the current Black River Pump Station operation plan, Black River Pump Station capacity, P-1 channel improvements, future land use conditions, the proposed City of Kent Lagoons project, and other i frastructure improvements planned by the City of Kent and the V ashington State Department of Transportation. The result of these improvements and future development result in Springbrook Creek water surface elevations considerably lower than those reported by FEMA. In fact, the most extreme water surface elevation reported is approximately 13.2 at the practice track outfall under future 100-year, "storage" conditions assuming no further capacity improvements. This is 3.2 feet lower than that reported by FEMA. These elevations are summarized in Appendix G. As discussed in Section VI(C) of this report, the City of Renton now utilizes the results of it's latest modeling to determine flood elevations for the purpose of compensatory storage. She City of Renton is currently coordinating additional pringbrook Creek channel improvements from SW 16th Street upstream to a point south of the future Oakesdale Avenue SW bridge at Springbrook Creek. These improvements are being made ip the same time frame as the Oakesdale Avenue SW project to limit disturbance to the creek, wetland areas and adjacent property cfwners. The improvements will somewhat reduce flood elevations from those currently modeled, by improving channel capacity and i I storage volume. 4. Black River The Black River as it exists today is 1 mile in length and its confluence with the Green River is 11.0 miles upstream of Puget Sound. A pumping station is located on the Black River 0.3 miles upstream of its confluence with the Green River. The watershed area at the pump station is 24.8 square miles which includes the Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2210\wp\dmrpt01.doc II1-4 September 1998 21.9 square miles of Springbrook Creek. The pumping station has no gravity flow provisions. All upstream flows must be pumped up to a gravity open channel which discharges to the Green River. The fully installed nominal rated pumping capacity of the station is 2,945 cfs. There are eight main pumps with one of the larger pumps currently off-line. There are five diesel pumps rated at 514 Ids, two diesel pumps at 150 cfs, and one automated electric pump rated at 75 cfs. The FEMA study. was based on the nominal installed capacity at the time of 875 cfs as the pump station's firm capacity of maximum discharge.. The_pump station has a forebay called the P-1 pond storage area) that was expanded by excavation in 1984. The pump station's current installed nominal operating capacity is 2,431 cfs. The 1989 FEMA study indicates that peak outflows from the pump station had not exceeded 525 cfs (November, 1986 event with nominal P-1 pond storage). On March 4, 1991, the pump station operator indicated he was pumping at a rate of 750 cfs. During the February 1996 event the pump station operator had to operate 1 large pump, the two medium pumps, and the small pump for a combined nominal capacity of 889 cfs. According to the pump station's operating plan, the first large pump is to be activated when the level in the forebay reaches elevation 4.0. According to FEMA, a Green River flow of 12,000 cfs equates to levation 19.0 downstream of the pump station. The pump room oor elevation is 25.0 NGVD. Since all upstream flow must be umped the electric pumps are automated by float switches. The urger diesel pumps must be manually started and are used as required to pump out the storage pond. Trash racks are cleaned periodically depending on the debris build-up. There have been Some flap gate failures with the rocker arm breaking off. However, the pump bays can be isolated from backflow with stoplogs. II Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil. Ina. 014002\2220\wp\dmrpt01.doc III-5 September 1998 An upstream fish ladder at the pump station is operated during the upstream migration period from mid-September through January. Between early April and mid-June the downstream migration is accommodated by an air lift system. A simplified fish counter consisting of a paddle in the upstream migration trough counts electronically the number of fish passing. Historical fish counts are as follows (H. Allmendinger, personal communication): Black River Fish Counts Season Number of Fish 83-84 155 84-85 119 85-86 47 86-87 82 87-88 166 88-89 95 89-90 77 90-91 70 91-92 107 92-93 291 93-94 120 94-95 268 95-96 355 96-97 206 B. Task 1: Study Area Definition and Maps The project site falls within Sections 24 and 25 of Township 23N., Range 4E., W.M.. The triblitary' drainage area to the proposed project site is shown in Figures B.1 and C.1. igure B.1 shows that under existing conditions, the proposed project site falls within portions Drainageionsofon-site Basins 3 and 4. Figure C.1 Ihowsthatconstruction of the proposed project will alter these on-site drainage pasins. Following construction, Sub-basins 4-1, 4-4, and 4-5, are combined with Basin 3 to create Basin A. The limits of Sub-basin 4-3 will not be altered by this roject. Following construction, this sub-basin becomes Sub-basin B-2. urrently, runol ff from the BCAG Headquarters Building site, located within asin 4, is collected in the building, landscape, and parking areas and routed to and "B", the former practice track swale, and ultimately to Springbrook Creek. s part of the Surface Water Management Project, Pond "B" will be filled in and noff from the BCAG Headquarters Building site will be re-routed to the combined wetpond/detention pond located at the south end of the project site. Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2220\wp\dmrpt0l.doc 111-6 September 1998 i The combined the CSTC MainPond pond will drain to the CSTC Main Pond. Discharge from P nd will continue to flow over a weir to the CSTC Delta Area, through a large precast concrete vault structure housing a timber weir and fish screen, and finally, through a 36-inch ductile iron pipe with an elastomeric check valve to Springbrook Creek. C. Task 2: Resource Review In accordance with the requirements of Task 2 of the Off-Site Analysis Section of the King County Surface Water Design Manual, the following table shows the resources reviewed regarding existing and potential flooding and erosion problems for t1ie project area: Resource Findings Basin Reconnaissance Summary Reports The City has extensively studied the East Side Green River Watershed and produced the Draft East Side Green River Watershed Project,Plan and Environmental Impact Statement,December 1996. This report includes information related to existing and proposed conditions within the basin,proposed improvements,and hydrologic and hydraulic analyses of these conditions. Critical Drainage ea Maps As described above,the project is within the East Side Green River Watershed. FEMA Floodplain Maps Flood Insurance Rate Map Panel 53033C0978F This project is outside the limits of the Springbrook Creek floodway but is within the flood fringe,or that portion of the plain outside the floodway which is covered by flood waters during the base flood. King County Sensitive Areas Folio Wetlands-No portions of the project area are listed as wetland areas in the folio, however, wetland mapping has been completed for this project area, identifying a number of small wetland areas which will be impacted or restored. Impacted wetlands will be mitigated by this project. Stream and Flood Hazard Areas-No portions of the project area are indicated to be within streams or 100-year floodplains,however,the project does drain to Springbrook Creek,which is a Class 2(with salmonids). Erosion Hazard Areas-No portions of the project area are classified as erosion hazard areas. Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil. leo. 014002\2220\wp\dmrpt01.doc 111-7 September 1998 1 I 1 Resource Findings Landslide Hazard Areas-No portions of the project area are classified as landslide hazard areas. Seismic Hazard Areas- No portions of the project I area are considered seismic hazard areas. Coal Mine Hazard Areas-No portions of the project area are considered coal mine hazard areas. ` liienton SWM Division Drainage Services No problems are documented at this project site. All P oblem Database drainage,flooding or erosion problems within the Springbrook Creek main stem are being addressed by the City's channel improvement projects. SDA King County Soils Survey This information is shown in the drainage basin mapping of Appendix B and C. Most of the project site soils are classified as Urban Land. D. Task 3: Field I spection 1 Sverdrup completed a field visit May 28, 1998. The temperature was about 65°F and the sky was clear. According to National Weather Service (NWS) records for i t e Sea-Tac International Airport Station, total precipitation for the 6 days receding the May 28th field investigation was 1.00 inches. The investigation levealed that some portions of the existing Boeing drainage system (open iChannels) outside of the CSTC, Headquarters and Family Center sites were I covered by vegetation, but no evidence of flooding, erosion or plugging was 41pparent. It has also noted that each of the proposed project site discharge 1 locations at Springbrook Creek were operating correctly and showed no signs of • erosion. The northern discharge point consists of a 36-inch ductile iron pipe with an elastomeric check valve, and the southern discharge point is a 36-inch steel tide ate at the practice track outfall (at the east property line, just upstream of Springbrook Creek). E. Drainage System Description and Problem Screening Minor cleaning of the existing open channels outside of the CSTC, Headquarters and Family Center sites will ensure that flows are unrestricted. F. Mitigation Minor cleaning of the existing open will ensure that the existing system operates s intended. Surface W ter Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil. Inca. 014002\22 0\wp\dmrpt01.doc III-8 September 1998 G. Previous Studies Numerous studies and reports have been written about the area in the vicinity of Longacres Office Park. In addition to those reports listed in Section 11(B)11, some of the more pertinent studies are as follows: 1.Soil Conservation Service P-1 and P-9 Channel studies. 2. FEMA Flood Insurance Study of Renton,May 20, 1996 3. U.S. Department of Army Corps of Engineers Green River Flood Reduction Study, 1984. 4.King County Department of Public Works Green River Management Agreement, July 18, 1985. 5. Kramer, Chin & Mayo, Inc., December, 1986, City of Tukwila, Nelson Place/Ilongacres Drive Basin Drainage Study. 6.Kramer, Chin & Mayo, Inc., June, 1988, City of Tukwila, Nelson Place/Longacres Way Storm Drainage System Preliminary Design. 7.King County, revised September 29, 1989, Washington FEMA Flood Insurance Study, Four Volumes. 8. Jones & Stokes Associates, Inc., May, 1990, City of Tukwila, Water Resource Rating and Buffer Recommendations. 9. Landau Associates, Inc., August 31, 1990, Environmental Site Assessment Broadacres Property Renton, Washington, Volume I. 10. L.C. Lee & Associates, Inc., January 3, 1991, An Analysis of the Distribution and Jurisdictional Status of Waters of the United States Including Wetlands, at Longacres Park, Renton, Washington. 11. Herrera Environmental Consultants, Inc., October 10, 1991, Water Quality Monitoring and Quality Assurance Project Plan for the Black River Water Quality Management. 12. Sverdrup Corporation, April 30, 1991, Draft Flood Plain and Storm Water Report for Longacres Park Site Development. 13. R.W. Beck & Associates, September 1992, City of Renton Surface Water Utility Technical Memorandum; Boeing CSTC Facility Floodplain Analysis Review. Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt0l.doc III-9 September 1998 I ' 1 4. Sverdrup Corporation, October, 1992, Technical Information Report on the Floodplain/Stormwater System for Customer Services Training Center Site Devll elopment, Support Facilities and SW 16th Street, Renton, Washington. 1•. Hammond, Collier & Wade-Livingstone Associates, Inc., December 29, 1992, City of Tukwila Nelson Place/McLeod/Boeing CSTC Storm Drainage Study Technical Report. 16. Sverdrup Civil, Inc., November, 1994, U.S. Army Corps of Engineers,404 Clean Wter Act Alternatives Analysis. 17. L.C. Lee & Associates, Inc., November 14, 1994, Manual for Monitoring Maintenance of Water Quality in Stormwater Ponds & Wetlands at the Boeing CSTC. 18. Northwest Hydraulic Consultants Inc., March 1996, East Side Green River Watershed Hydrologic Analysis. 9. R. W. Beck, March 1996, East Side Green River Watershed Project Hydraulic Analysis Report, Existing Drainage System. 0. R. W. Beck, December 1996, City of Renton East Side Green River Watershed Project, Plan and Environmental Impact Statement (Draft). 1. Sverdrup Civil, Inc., July, 1997, Drainage Report, BCAG Headquarters Building 25-20 Site Development, Renton, Washington. 2. Sverdru o Civil, Inc., January, 1998, Drainage Report, Boeing Family Center Building 25 10 Site Development, Renton, Washington. I Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\22/0\wp\dmrpt01.doc III-10 September 1998 IV RETENTION/DETENTION ANALYSIS AND DESIGN A. Existing Site Hydrology The Surface Water Management Project site is located at Longacres Office Park in the City of Renton. The project site is located between the Green River hannel on the west and the Springbrook Creek Channel on the east. To the immediate north is the Boeing CSTC Site and to the south are the remnants of the main horseracing track. The 35 acre Surface Water Management site development itself includes remnants of the previous horse racing facility, such as a portion of the main racing track, several trees, a portion of the practice track racing oval and existing utilities. The j majority of the Surface Water Management site is relatively level with elevations generally between 11 and 16. The pre-development drainage basins for the entire CSTC and Longacres Office Park sites are shown in Appendix B. Only two local basins are impacted by the Surface Water Management project; Basins 3 and 4. 1. Basin 3 -North Main Track Basin This basin is detailed in Figure B.1, Appendix B. This basin covers 73.9 acres and contains three study areas which drain to the Boeing CSTC Main Pond. The first area is the CSTC Site and the second is a portion of SW 16th Street. The CSTC site encompasses 48.2 acres to the south of SW 16th Street, and the SW 16th Street study area totals 3.1 acres. The remaining 22.6 acre area is made up of the northern portion of the previously demolished main racing oval and infield which drains overland to the CSTC Main Pond. Flow leaves the CSTC Pond (Sub-basin A- 2) and flows over a V-notch weir before entering the Delta Area Sub-basin A-3) and flowing to the CSTC Site outfall. The CSTC Site outfall is made up of a large precast concrete vault structure housing a timber weir and fish screen which directs flow under a public pathway and vegetated bank through a 36-inch ductile iron pipe with an elastomeric check valve at a riprap-protected outfall. More detailed explanations of the CSTC Site and SW 16th Street conveyance systems can be found in Section V of the CSTC Site Development TIR. 2. Basin 4- South Main Track Basin This basin is detailed in Figure B.1, Appendix B. This basin includes 90.9 acres and has been divided into six subbasins. Subbasin 4-4 drains into Subbasin 4-1 through existing 12-inch storm drains south of the main track and outfalls into the main Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. 014002\2220\wp\dmrpt01.doc IV-1 September 1998 I,I tr ck swale. Subbasin 4-1 then enters an existing 12-inch storm II drain at the north end of the main track swale, draining the southern half of the main racing track, and flows to a recently constructed 24-inch RCP which also collects flows from Subbasin 4-15 (via the 25-20 site Pond `B"). Flow is then conveyed to an existing 36-inch CMP which discharges inside the north end of the foIrmer practice track within Subbasin 4-3. Subbasin 4-2 flows to it an existing 12-inch culvert under Oakesdale Avenue SW and discharges to a swale inside the former practice track. Subbasin 4- 6 drains through Pond "C", which collects runoff from the B ilding 25-10 site, to the swale inside the former practice track. Finally, all six subbasins join inside the practice track swale within Subbasin 4-3) and enter an existing 36-inch CMP located under the practice track and protected from backwater events with a cast iron flap gate at the east Boeing property line. From this point, flow travels through an open channel and finally through a short 36-inch CMP which ultimately discharges to Springbrook eek. Hydrogr phs were developed for the pre-development Surface Water Managerrient Project site conditions for the Water Quality Event, the 2-, 5-, 10-, 25-, 50-, and 100-year, 24-hour. A summary of these hydrographs and site parameters used to generate them are detailed in Appendix B. Detailed information is also provided in Appendix B, including soil groups, hydrologic soil groups, runoff curve numbers, existing land use descriptions, areas of each particular land use, time of concentration Paramet rs and detailed basin (hydrograph) reports. B. Developed Site Hydrology The post-development Surface Water Management Project drainage basins are shown in,Appendix C. The areas of re-development Basin 4 which I PP P are located west of Oakesdale Avenue SW (70.1 acres) are combined with pre-development Basin 3 creating post-development Basin A. The remaining areas of pre-development Basin 4 which lie on the east side of Oakesdale Avenue SW create post-development Basin B. Both Basin A and Basin B continue to drain into Springbrook Creek at the same locations as pre-development conditions. 1. Basin A- CSTC Site Basin The boundaries of Basin A are the same as pre-developed conditions for Basin 3, except that pre-developed Subbasins 4-1, 4-4, and 4-5 are re-routed to Basin A due to the elimination ofPond"B". Basin A total area is increased to 144.0 acres. Surface W'ter Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil. Inc. 014002\22.0\wp\drnrpt0l.doc IV-2 September 1998 1 I i 2. asin B - South Main Track Basin hree of the six subbasins in Basin B that were located west of Oakesdale Avenue SW have been combined with Basin A. The three remaining subbasins east of Oakesdale Avenue SW were Used to analyze runoff quantities, see Appendix C, Figure C.1. The subbasin boundaries are the same as pre-developed conditions for the subbasins located east of Oakesdale Avenue SW, except that area were renumbered as Subbasins B-1, B-2, and B-3. The total area of Basin B is reduced to 20.8 acres. Post-development hydrographs were developed for Basins A and B for the Water Quality Event, the 2-, 5-, 10-, 25-, 50-, and 100-year, 24-hour event. A summary of these hydrographs and site parameters used to generate them are detailed in Appendix C. Detailed information is also provided in Appendix C, including soil groups, hydrologic soil groups, runoff curve numbers, existing land use descriptions, areas of each particular land use, time of concentration parameters and detailed basin (hydrograph) reports. C. Hydrologic Analysis 1.Hydrograph Method In accordance with Chapter 3 "Hydrologic Analysis" of the KCSWDM, the hydrologic analyses in this Report are based on a Single-event SCS-type model known as the Santa Barbara Urban Hydrograph (SBUH) method along with the User 1 design storm rainfall distributions. This design storm hyetograph was interpolated by King County Surface Water Management Division staff, and resolved to 10-minute intervals. Discussions with King County staff indicate that the distribution shown on page 3.5.1-2 of the King County.Surface Water Design Manual (and termed Type 1A) is actually a slightly modified version of the SCS Type 1A, and they consider it the "User 1" distribution. All analyses in this report utilize the User 1 distribution, which is identical to the KCSWDM's definition of a Type lA distribution. 2.Computation Software All SCS runoff curve numbers are based on Table 3.5.2B of the KCSWDM, and are tabulated and combined for input into the lydrology software with a spreadsheet created by Sverdrup Civil, Inc. Time of concentration calculations are also computed by a spreadsheet, completed in accordance with page 3.5.2-5 of the Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. 014002\2220\wp\dmrpt01.doc IV-3 September 1998 KCSWDM. Hydrologic analyses were completed using WaterWorksTm hydrology software, Release 4.13c. 3. Design Storm Precipitation Values Total precipitation values for each design storm event were interpolated from isopluvial maps found in the KCSWDM, Tables 3.5.1C to 3.5.1H, as noted below: I Precipitation Design Values Design Storm Event Total Precipitation (inches) Water Quality 0.67 (P2/3) 2-year, 24-hour 2.00 5-year, 24-hour 2.40 10-year, 24-hour 2.90 25-year, 24-hour 3.40 50-year, 24-hour 3.45 100-year, 24-hour 3.90 100-year, 7-day 9.80 I. Retentio 1 etention System 1. Overview Following completion of the Surface Water Management Project, ' tie area west of Oakesdale Avenue SW drains to Pond "D" and the enlarged CSTC pond. Pond "D" is designed as a combination wetpond/detention facility. Pond"D" has a dead storage volume of 2i61,800 cubic feet from El 3 to 8.5, not including the bottom 1 foot '! of sediment storage, and a live detention storage volume of 302,900 cubic feet from El 8.5 to 12. The enlarged CSTC pond has a dead storage volume of 1,186,000 cubic feet from El 3 to 8.5, not including the bottom 1 foot of sediment storage, and a live detention storage volume of 1,400,000 cubic feet from El 8.5 to 12. Both ponds have a combined dead storage volume of 1,447,800 cubic feet and a live detention storage volume of 1,702,900 cubic feet. After completion of the Surface Water Management Project, al 100-year 24-hour storm event will require a detention volume of 743,200 cubic feet, corresponding with elevation 10.20. This is based on a future 2-year storage event tailwater influence at , pringbrook Creek of EL 8.60 (high tailwater impacts are addressed in Section V(B). The 2-year tailwater influence was alssumed for the following reasons: I Surface Wa er Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil. leo. 014002\222t\wp\dmrpt01.doc IV-4 September 1998 I 1) The conveyance event is the critical condition for flow velocities in Springbrook Creek. 2) City of Renton policy is for live storage to be above the 2-year elevation in Springbrook Creek, which is elevation 9.15. 3) Since this analysis does not use a model configured to simulate a changing tailwater, a single tailwater had to be selected. The 2-year elevation in Springbrook Creek at the outfall was selected as the design tailwater because of potential for non-coincidence with main stem Springbrook Creek peaks and the size of the pond is largely determined by the 2-year events (the lowest frequent event required to meet detention standards). In the future, Pond "D" and the enlarged CSTC pond will provide detention for buildout of the Longacres Office Park west of Oakesdale Avenue SW. Based on the current masterplan at full buildout, the required detention volume for a 100-year 24-hour storm event will be 761,156 cubic feet, corresponding with elevation 10.23 using the 2-year tailwater elevation of 8.60 in Springbrook Creek. Stage-storage table, stage-discharge tables, peak inflows, peak outflows and corresponding stages for Basins A and B are shown in Appendix D. 2. Hydrograph Routing The proposed Surface Water Management Project site lies within drainage basins 3 and 4 (also A and B). Drainage basin 3 (also A) was divided into two pre-developed (A-2 and A-3) and three post- developed (A-1, A-2, and A-3) subbasins. For pre-development, Subbasin A-2 was routed through the CSTC Pond and over a V- notch weir upstream of the Delta Area. The flow over the V-notch weir was combined with Subbasin A-3 and routed through the CSTC discharge vault and into Springbrook Creek. Basin 3/A was not divided into subbasins in previous reports. However, since Basin 3/A was divided into three post-development subbasins, the Post CSTC, Post Building 25-20, and Post Building 25-10 Basin 3's also had to be divided up and re-routed to allow a comparison. Refer to Appendix D for the routing calculations. Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\drnrpt01.doc IV-5 September 1998 Post-development Subbasins A-1 and A-2 were routed through Pond "D", through the enlarged CSTC pond, and over the V-notch weir. Flow over the V-notch weir was then combined with Subbasin A-3 and routed through the CSTC discharge vault to jI Springbrook Creek. Drainage basin 4 (also B) was divided into six pre-developed (4-1 tl}rough 4-6) and three post-developed (B-1, B-2, and B-3) subbasins. For the pre-development Surface Water Management Project routings the hydrographs for Subbasins 4-1 and 4-4 were added together and routed through the main track swale. Subbasin 4-5 was routed through Pond "B" and combined with Subbasins 4- 1 and 4-4 in a 24" storm drain on the 25-20 Building site. Subbasins 4-1,4-4, and 4-5 were then routed through the 24" storm drain to the practice track. Subbasin 4-6 was routed through Pond C" at the 25-20 Building site to the practice track. All six Subbasins were then combined at the practice track and routed t rough the practice track to Springbrook Creek. Post-development Subbasin B-3 was routed through Pond "C" and thl en combined with Subbasins B-1 and B-2 at the practice track. All three subbasins were then routed through the practice track to Springbrook Creek. The overall release rate from Basin 3/A to Springbrook Creek for a 1100-year 24-hour storm event,increased from 6.67 cfs to 17.85 cfs. The increase was caused from re-directing 70.1 acres from Basin 4B to Basin 3/A. The reduction in area for Basin 4B reduced the release rates from Basin 4/B to Springbrook Creek for a 100-year 4-hour storm event from 17.30 to 9.05 resulting in an increase of only 2.97 cfs in the overall release rate from the Longacres site to Springbrook Creek during a 100-year 24-hour storm event. The Overall release rate is still 15.26 cfs less than baseline conditions. efer to Appendix D,Table D.1 for details. 3. Summary of Hydrologic Analysis Avariety of tables and figures have been created to summarize the hydrologic and hydraulic analyses completed for this project. They re in Appendix D. E. Water Quality System The Surface Water Management Project does not add more than 5000 square feet of pollution generating impervious pavement. However, Pond u Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\22i0\wp\dmrpt01.doc IV-6 September 1998 B" currently provides water quality treatment for the 25-20 Building site and wil be eliminated. Stormwater from the 25-20 Building site will be re-routed to Pond "D" and Pond "D" will provide water quality treatment. Pond "D" was designed as a combined wetpond/detention pond in accordance with the KCSWDM as adopted by the City of Renton. Water quality design calculations for Pond "D" are shown in Appendix F. Appendix E contains water quality data derived from samples taken from Springbrook Creek and the site prior to any Boeing development. This information shows the relatively poor water quality of the creek and some on-site locations. The on-site wetpond/detention system will improve the quality of runoff leaving the project site and will help improve the water quality of Springbrook Creek. Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Ina. 014002\2220\wp\drmpt01.doc N-7 September 1998 V ONVEYANCE SYSTEM ANALYSIS AND DESIGN A. Propose Conveyance System Overview Storm water runoff from the 25-20 site will be rerouted through a 24-inch reinforced concrete pipe to Pond "D", which is a combination wetpond%detention pond. From Pond "D", flow will pass through culverts to the enlarged CSTC pond. The CSTC pond drains through a narrow stream acid over a 120 degree V-notch weir to the CSTC Delta area. The , The CS''C Delta area drains through a large precast concrete vault structure housing a timber weir and fish screen, and through a 36-inch ductile iron pipe with an elastomeric check valve to Springbrook Creek. Conveyance System Analysis and Design: The proposed conveyance system for the project site is designed to conform with Chapter 4 of the KCSWDM which provides approved methods and criteria for hydraulic analysis and design of storm drainage facilities. 1. niform Flow Analysis Method The proposed storm drainage pipelines were preliminary sized using the Rational Method for Conveyance System Analysis and Sizing - Uniform Flow Condition table in Appendix G. This table is based upon Figure 4.3.3C of the KCSWDM. Footnotes at the Ind of the table explain the various information sources and assumptions. 2. Filackwater Analysis Method Selected storm drainage pipelines will be analyzed using King County Surface Water Management's "BW" computer model, Version 4.22. The pipeline segments analyzed will include the lllongest segments of the system and those which have the lowest iipstream grate elevations. Tailwater elevations for the analyses vill be based on the 2-year storm event elevation within Springbrook Creek as determined by the City's East Side Green River Watershed hydraulic modeling effort. 3.System Materials The storm drainage system that will be constructed to reroute flows from the 25-20 site to the proposed wetpond/detention pond (PondI` D") will be reinforced concrete pipe. Culverts will be installed to I Surface W terManagement Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. 014002\270\wp\drnrpt01.doc V-1 September 1998 II connect Pond "D" to the enlarged CSTC pond. Perforated PVC underdrain pipes will be placed in existing ditches that are to be filled as part of this project. Surface Water Management Pr4ect-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2220\wp\dmrpt0l.doc V-2 September 1998 VI FLOODPLAIN AND GROUNDWATER INFORMATION A. Baseline Floodplain Conditions According to the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map Panel 53033C0978F and Flood Profile 45P for Springbrook Creek, the 100-year floodplain elevation in the vicinity of this project is 16.4 feet based on National Geodetic Vertical Datum (NGVD) of 1929. The.FEMA map showing existing floodplain at elevation 16.4 is detailed in Appendix A, Figure A.1. Some discrepancy with actual conditions exists,as shown in Figure A.5, which is a baseline topographic survey of the site shaded to depict actual-areas at or below elevation 16.4. Actual floodplain volume calculations utilize the FEMA 16.4 foot flood elevation and actual topographic surveys. Flood profiles of the Black River an Springbrook Creek are included in Appendix A, Figures A.2, A.3 and A.4.' For the purpose of backwater analysis of the proposed conveyance system, Springbrook Creek elevations (forming site tailwater) are based on the City of Renton East Side Green River Watershed Model rather than the FEMA flood profiles. This design assumption is based on review comments from city staff on the Building 25-20 Site Development Drainage)Report for Conceptual Drainage Plan, December 20, 1996. Prior to construction at the CSTC site, an existing outlet culvert with a tide gate prefented inflow to the site from Springbrook Creek. However, the site had kn existing bank, or sill, located approximately above the outlet culvert 4nd allowed flow into the site only when the Creek elevation exceeded elevation 15. The sill provided enough capacity to inundate the entire sitr, flooding all connected areas to elevation 16.4 even without any on-site sItorniwater storage at the time of flooding. Note that City of Renton review comments on the Drainage Report for Conceptual Drainage Plan for the 25-20 project required that detention facility live storage volume be excluded from the compensatory storage determination. This differed from the determination method used for the CSTC Site Development TIR, which did include the live storage volume. To account for this !difference in methodology, the floodplain volume for baseline conditions were recalculated. The revised calculation yielded a cumulatitve storage volume of 265 acre-feet at elevation 16.4 for the Longacres Office Park site under baseline conditions. The starting elevation for floodplain storage was assumed to be the pre-development peak stage elevation for each of 5 on-site basins. The peak stage of the various detention -facilities was determined based on free discharge conditions to,Springbrook Creek. Surface Water Management Proj ct-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\drmpt01.doc VI-1 September 1998 I I The City of Renton made an Administrative Policy Determination, dated June 26, 1997, that allows the use of the City's model results for determining the volume of compensatory storage required for filling within the 100-year floodplain of Springbrook Creek. According to the policy determination this applies only to current and future projects and is not to be applied retroactively. However, according to the December 22, 1997 review comments on the Conceptual Drainage Report for the Family Center Building 25-10 site project, the retroactive provision of.the policy will not be applied to the Longacres Park Site. Furthermore, the City does i_-- not require recalculation of floodplain volumes since there will be no filling pelow the City's 100-year floodplain elevation of 13.2. For more detail, refer to Table 7-3 of the ESGRWP draft plans included in Appendix A,Figure A.9. B. Existing Floodplain Conditions Existing floodplain conditions for the Surface Water Management Project analysis are those that existed when Boeing purchased the Longacres Site, as since modified by construction of the CSTC, 25-20, and 25-10 projects. According to the City's model results, the project site floodplain elevation under future, "storage" event is elevation 13.2. The existing project site does not include areas subject to flooding by Springbrook Creek at or below elevation 13.2 due to check valves at both existing site outfalls and topography along the creek. C. Proposed Floodplain Conditions The floodplain as modified by the proposed project is detailed in Appendix A. D. Groundwater Influence A geotechnical report completed April 23, 1998 by GeoEngineers, Inc. provides specific information about the groundwater at this project site. Groundwater conditions were evaluated by measuring the water level in nine mlnitoring wells installed at depths of 8.5 to 9 feet and at depths of 16.5 feet. Groundwater levels were measured 3 times between April 9, 1998 and April 21, 1998, following publication of this report, the wells have b en measured at least monthly. Throu h September 1998, groundwater levels measured in the wells installed at depths of 8.5 to 9 feet ranged from Elevation 4.1 near the CSTC pond to an Elevation less than 7.5 near the central portion of the southern lobe. Groundwater levels measured in the wells installed at a Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt0l.doc VI-2 September 1998 II depth of 16.5 feet ranged from Elevation 6.1 near the CSTC pond to Elevation 7.2 near the central portion of the southern lobe. The report states that "The ground water measurements to date show that there is a downward flow gradient between the upper silt and underlying sand. Based on the previous ground water level measurements completed in 1991, we (GeoEngineers) expect that the ground water levels will fluctuate between 3.5 to 4.5 feet annually. This would result in an estimated high ground water level of about Elevation 10 in feet in April to it a low of about Elevation 2 feet in October." Groundwater levels will continue to be measured at least monthly through early 1999. I ' II li Surface Wa er Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt0l.doc VI-3 September 1998 VII EMPORARY EROSION/SEDIMENTATION CONTROL Temporary Erosion/Sedimentation Control (TESC) Plan The TE C plan is designed to comply with Chapter 5 of the King County Surface Water Design Manual (KCSWDM) as adopted by the City of Renton. The first detail sheet in the TESC plans lists the standard City of Renton Erosion Control Notes (from the Drafting Standards) as well as II applicable requirements from the KCSWDM Reference - 9 Standard Plan Notes. ce the notes are based on two independent sources and often have thearasame intent, they are organized to match the recommended construcion sequence as shown at the end of Reference - 9. Detail sheets of the Erosion/Sedimentation Control Drawings are included in Appendix I. Complete TESC plans will be made part of the site development drawings for this project. NPDES Requirements I I Since this project will disturb more than five acres of total area, the applicant will file a Notice of Intent (NOI) for coverage of this project under the Baseline General Permit for Stormwater on or about October 16, 1998. Additionally, the applicant will prepare a Storm Water Pollution Prevention Plan to fulfill the requirements of the Federal Water Pollution Control Act (33 USC 307) and the State of Washington Water Pollution Control Law (Chapter 90.48 RCW), and regulations that address the control of storm water discharges (40 CFR, Parts 122, 123, 124; WAC 173-201AI , 216, 220 and 226). The Plan will be completed after this drainage(report is completed. I I it Surface Wat?r Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220'wp\dmrpt0l.doc VII- 1 September 1998 i I FIGURES Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt0l.doc Figures September 1998 I Page 1 of 2 King I countyounty Building and Land Development Division 1 TETHNICAL INFORMATION REPORT (TIR) WORKSHEET PART 1 . PROJECT OWNER AND PART 2 PROJECT LOCATION PROJECT ENGINEER AND DESCRIPTION I PIroectOwner The Boeing Company ProjectName Surface Water Management Proj:ct Address 1901 Oakesdale Ave SW Location Township 23 NPhoneRentonWA98055 1 Range 4 E Project Engineer Conrad Szymczak Section SZ Sec 24 NZ Sec 25 Company The Boeing Compatly Project Size 35 AC Address Phone t425) 477-0094 Upstream Drainage Basin Size Nelson P1 AC 93 I PART 3 TYPE OF PERMIT APPLICATION PART 4 OTHER PERMITS ManagementIIISubdivisionnDOF/G HPA Shoreline Mana g i, I I I Short Subdivision I X I COE 404 n Rockery Grading DOE Dam Safety 0 Structural Vaults Commercial n FEMA Floodplain Other 11 I I Other I fl COE Wetlands 0 HPA PART 5 SITE COMMUNITY AND DRAINAGE BASIN Community City of Renton Drainage Basin Spri ngbrook Creek I PART 6 SITE CHARACTERISTICS I River I X I Floodplain Springbrook Creek, Zone AE 1 AlStream Spri ngbrook Creek I k I Wetlands Urban disturbed Critical Stre im Reach I I Seeps/Springs I I Depressions/Swales I 0 High Groundwater Table 1 I 1 Lake 1 Groundwater Recharge I I Steep Slope 0 Other I Lakeside/Er sion Hazard I 1 PART 7 SOILS Soil Type I Slopes Er sjon Potential Erosive Velocities Urban Lnd 3:1 ,Maximum Low/Minimal 5.0 ft/s maximum i I I I Additional Sheets Attatched I 1 1/90 I Figure 1 11 1 Page 2 of 2 King'County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET I•ART 8 DEVELOPMENT LIMITATIONS REFERENCE I LIMITATION/SITE CONSTRAINT I X 1 Ch.4-Downstream Analysis l Black River (P.1) Pump Station* 1 fl I I.II I Additional Sheets Attatched 1 *No effect on Project. i PART 9 ESC REQUIREMENTS MINIMUM 'ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING Cr NSTRUCTION FOLLOWING CONSTRUCTION X I Sedimenta ion Facilities 1 Stabilize Exposed Surface I Remove and Restore TemporaryXIStabilizedConstructionEntrancelX_ p ry ESC Facilities X Perimeter Funoff Control I X I Clean and Remove All Silt and Debris X 1 Clearing a d Grading Restrictions I X I Ensure Operation of Permanent Facilities X 1 Cover Practices 0 Flag Limits of NGPES X I Construction Sequence 0 Other Other 1 I ART 10 SURFACE WATER SYSTEM :- I I 1 Grass Lined Channel CI Tank fl Infiltration Method of Analysis I X I Pipe System I I Vault 0 Depression SBUH "User 1" I 1 Open Channel I I Energy Dissapator = Flow Dispersal Compensation/Mitigation I I Dry Pond CI Wetland Waiver of Eliminated Site Storage I X I Wet Pond Stream Regional Detention 11 Brief Description of System Operation See Drainage Report, Sections IV and V. 1 Facility Related Site Limitations I I—I Additional Sheets Attatched Reference Facility Limitation 1 I 1 PART 11 STRUCTURAL ANALYSIS PART 12 EASEMENTS/TRACTS May require special structural review) ' E, :: . Drainage Easement O Cast in Place Vault 0 Other 0 Access Easement i 0 Retaining all 1 Native Growth Protection Easement I I Rockery>4'High I—I Tract I I Structural oIn Steep Slope 1 El Other 1 ART 14 SIGNATURE OF PROFESSIONAL ENGINEER ' S • S I or a civil enginleer under my supervision have visited the site.Actual site conditions ads observed were incorporated into this worksheet and the 91e/attatchments. 1)o the best of my knowledge the information provided 9,6Q,/i/441 8 here is accurate_ ao.r. 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Dashlir t 5 1-1 Co Collage O e,l • / Point y d 1- S 5 'E 3an 5 \i rnr 3h.15TN sr 5E 317TH 5T f j, 370M ST O® ent ST SE BLACK DM,+ONO t •\:.,..., NO O ID Feder.I W.Auburn .. ro L lP 08r0,rrs t oY lrE . nnr 8 .aoREN SNDBt r V SW e• • lr2 T Cti t Huhn lh,r.,•,h, h + Sw 1,, 336,H ®,3 Ir f t 11 AUBURN-B; 1 COMMENCEMENT M* or MPvS S IN*, Whrte nn rr'.): • "5I \bmc,.n,ahrBAYyr+• \ iG D .N... ISTN 51 sw ._ 4. Historn:.d lbh.:cun,4A15ER 40 NQ ... TA.G. LOCATION MAP Source: Washington Official State Highway Map, WSDOT FIGURE 3 Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\drnrptOl.doc Figures-3 September 1998 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT lack R fi j0i N, ,'` R F Q 1 r .. Y Black -Riuef V 3 it- i,' .B 3 7, um ping Sta r- r i l i ' C I I i Y. -en— -VI II if, *\ t u 1\ r.•pi I I 1. Power, . 6 PlantFr, NI ir41 m * t! Sewage ,' ••s+ .,r a:-: - - m i • s, lan$$$. • i:. . 4". -7 1 A_ 3.4' N''••`77314. 77gr----01-- i ill I.:%: ... ".. -"a'. - ... w•- ----- - . NAtillirr- i-.lir 411•T,.."--- ii., --,44.. 8 4 11 bsta• 1 1 ) 1-/...\ c ioltil41,, 1 10 /2 I1'l R PROJECT i.Ilig5/ v . y SITE f 1 t I , i -- 7:e of , , I 1 1j II t:::.._ ru ie I il . 104.. 1 i 25 I j I I rW _ . 1,Cs' " Tukwila I as lii* 7---0 I( bt /I I f di Greens ugg i I I w r i Os• I° i,k., . -r: Ii , K _ --_• _- LOIØ[I1t CORD ptc,4, 4, 11 i14. r1 ( pk"UII li l y' n )1///Ili i \\f VICINITY MAP Source: USGS Renton Quadrangle FIGURE 4 Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2220\wp\drnrpt0l.doc Figures-4 September 1998 APPENDIX A 11! 41 1, 111 ti Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. I; 014002\2220\wp\dmrpt01.doc Appendix A September 1998 APPEN IX A FLOODPLAIN INFORMATION This appendix contains floodway and floodplain information related to the project site. The information included,consists of FEMA mapping and floodway profiles as well as topographic survey of the site shaded to indicate areas at or below FEMA floodplain elevation 16.4. Also included are pre- and post-development floodplains delineated at elevation 13.0 to approximate the City's 13.2' floodplain. Portion of FEMA Flood Insurance Rate Map from Panel 978 of 1725, 5/16/95,Fig. A.1 FEMA Flood Profile: Black river,Fig. A.2 FEMA Flood Profile: Springbrook Creek, Fig. A.3 FEMA Flood Profile: Springbrook Creek, Fig. A.4 Pray-Development F1oodplain (16.4'), Surface Water Management Project ,Fig. A.5 , Pot-Development Floodplain (16.4'), SurfaceWater Management Project, Fig. A.6 Table 7-3 (13.2' Floodplain)from ESGRWP, R.W. Beck, dated Dec. 1996, Fig. A.7 Surface Water Management Project-Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. 014002\2220\wp\drnrpt0l.doc Appendix A-1 September 1998 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT t____ -7' Li SOUTHWEST 16THr--------..--------.----..- 8 I( R 334 7 24 jt O ZONE X r-ZONE X 16 V L. a r k 0z4,. , 2 LONG ACRES RACE TRACK SOUTH', i ZONE X M ZONE X ZONE AE fc- 7- ZON 0 ZONE X p 2 4 BRIDGE ZONE X fillr O I / . - - FEMA FLOODPLAIN MAP Source: Federal Emergency Management Agency (FEMA) FIGURE A.1 Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\drnrptO1 doc Appendix A-2 September 1998 I1 i 1 III I it II gELEVATION (FEETI NGVD) II' o o _ o a, o • cn N n>' i , • f • I ' ' ( 1 I , rl : " I.! I ' TLiTfT1Ti! fLrTiI • I1 , II • i ! ) . II1 . , I• • . • I ! I .I ONFLUENCE WIC AI I • 1 t-' 'r • +--- +.1.. _. . .I , GAEEr RIVER I I 1 I- I . ! i • I . 1 i I ! I _ 1 . : I I : . . i ' • i.. 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INC. all IBM a DEWIND a.IBM MEI ME AeSreiecnuwnt tea 1 : .r s POST-DEVELOPMENT FLOODPLAIN MAP (1e.49 Q BOI//VQ O• IIIPL I` gos SURFACE PROJECTREPORT FIG AGA•6km'ISsmunicO CNL VASIEG BoaNG LacN S OFFICE PNAI"" i I III I I I I TABLE 7-3 i Comparison of Peak Flows and Water Surface Elevation FEQ Computer Model and FEMA (1)VG. = 13, 1 ; Elevation Datum NGVD) a I I 1 Road- 100-YrCur.Flow 100-Yr Fut.Flow 100-Yr Cur.Flow 100-Yr Fut.Flow FEMA(5) way Top Conveyance(6) Conveyance(6) Storage(6) Storage(6), Elev. Location/Discription I 1 Flow Elev Flow Elev Flow Elev Flow Elev Flow Elev I I (efs) (feet) (cfs) (feet) (cfs) (feet) (cfs) (feet) (cfs) Panther Creek u/s of IR-I67(2)170 170 82 92 16.0 i Rolling Hills Creeka I Renton(2)(3) 1 1 167 21.8 174 21.8 87 20.7 99 20.9 130 i 4.0 Shopping Center Culv.Outlet 1 ' Rolling Hills u/s I-405 132'culvert(2)(3) ! i 167 17.8 174 17.8 87 16.8 99 16.9 91 24.0 SR-167 North Crossicig 100 17.0 98 17.0 58 15.2 69 15.6 16.0 I Springbrook Creek BRPS outflow 1044 1223 1360 1700 BRPS inflow 1044 4.1 1223 4.1 734 8.4 1153 13.0 1230 15.0 Grady Way u/s I 935 7.2 1110 7.6 638 8.6 1045 13.0 1100 '16.0 SW 16th Street 934 7.7 1106 8.2 577 8.6 960 13.0 16.4 Confluence of Rolling Hills Creek 930 11.0 1088 11.6 571 9.7 898 13.1 1 15.8 Confluence of Sr 23rd St Channel 819 12.0 989 12.6 502 10.4 807 13.3 I,16.0 sw 27th u/s 17.9 825 14.2 989 15.6 492 11.4 775 14.3 16.3 SW 34th u/s 14.9 887 15.4 1219 16.1 490 12.4 845 15.2 16.8 oakesdaled/s i i 17.1 891 16.0 1227 16.9 489 12.9 846 15.8 17.3 Oakesdaleu/s 117.1 833 17.4 1167 17.9 463 13.6 792 17.3 17.4 1 SW 43rd d/s 22.9 830 17.7 1158 18.3 459 14.0 783 17.6 _ 17.8 SW 43rd u/s i ' 22.9 830 18.2 1158 19.5 459 14.2 783 18.0 1055 17.8 Notes I1)FEMA uses current land use conditions and does not consider future land 1 conditions. Elevations are from FEMA floodway data tables. 2)FEQ simu ated flows at these locations are based upon frequency analysis of Springbrook Creek i flows to the BRPS forebay. Refer to ESGRWP Hydrologic Analysis Report(NHC, 1996) for flows I • based u I on frequency analysis of Panther Creek and Rolling Hills Creek. 3)Flows are)based upon assumption that capacity restriction through Renton Shopping Center is improved such tha no attenuation from isutiface ponding occurs. 4)u/s=upstream,d/s =downstream1 5)Rise in F 3MA water surface elevation at SW 16th Street from the confluence of Rolling Hills Creek is due to unresolved discrepa cy at the upstream boundary of 1989 FEMA restudy(FEMA,1989). 6)Conveyance event reflects a severe local rainstorm without pumping restrictions at the BRPS due to high Green River flows. Storage event reflects a high Green River flow event in which the BRPS must restrict pumping rates in accordance with GRIA. I 1 I ' I ' j I I I I I I ' FIGURE 7. 7 I I C 1 1 ! APPENDIX B Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\drnrpt01.doc Appendix B September 1998 I 1 it II APPENDIX B EXISTING SITE HYDROLOGY This appendix contai>is;information related to Section IV(A) "Existing Site Hydrology" and is organized as follows: 1. Basin 3 !,North Main Track Basin Figure 'll B.1 - Pre-Development Surface Water Management Drainage Basins.'' This figure indicates existing flow travel path information and existing' (conditions used to complete the Area Weighted Runoff Coefficient table,below. ji Table -,Area Weighted Runoff Coefficient. The table includes soil groups, hydrologic soil groups, runoff curve numbers, existing land use descriptions, and areas of each particular land use. This information is combined to determine the pervious and impervious- area runoff curve numbers. Table 1 j Pre-Development Surface Water Management Time of Concentration or Travel Time. II Detailed) pre-development Surface Water Management hydrographs for Water Quality, 2-, 5-, 10-, 25-, 50-, and 100-year, 24-hour events and the 100-year Iliday event. 2. Basin 4 L South Main Track Basin I 1 Figure 13.1 - Pre-Development Surface Water Management Drainage Basins. I This figure indicates existing flow travel path information and existing i conditionsi used to complete the Area Weighted Runoff Coefficient tables, below. Table - Area Weighted Runoff Coefficients for each subbasin. The tables include soil groups, hydrologic soil groups, runoff curve numbers, existing land use descriptions, and areas of each particular land use. This information is combined to determine the pervious and impervious area runoff curve numbers. I ! i Table - Pre-Development Surface Water Management Time of Concentration or Travel Times for each subbasin. 1l Detailed pre-development Surface Water Management hydrographs for each subbasin for Water Quality, 2-, 5-, 10-, 25-, 50-, and 100-year, 24-hour events and the 100-year 7-day event.1 Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. 014002\2220\wp\drnrpt01.doc Appendix B-1 September 1998 I NM 5-BASIN 4-8 1 4.'',' ' Z % W.''Z4*., SCALE: NONE SPRINGBROOK CREEK a ji+f ãti: 4& ii,-' - PROJECT SITE 4. - . l411., c.•• i II'. •,..4(..4:4•...-•*•144, .4, ' 0 n... . a moo.:+-k t 1 lz Li__ -.,,, 4 I.0‘,..t.-'.. t.,.., ii, SitE, 4 11 filoAli\i177 ,f-. .,1...„ .A.-,....-...1 e.,r.:Ittj, .."'-'7.-**74t---7-'---... 77-_-_-- ,...'' • I ';IflPiPbb.fttitit 1 I t•'.'t a 0 il at p a C 1-01-j _ .. 1.i..,''..... A..I i'•••.: Irk, ir ,r4000 ' ' 14i;',,-,----- 1, `...:"`' . -= I. ' .1 r..,.... 43, , 4 hit/ . ,,,../zsr_ ---....----,ar.s. .,11 111400i 1 f i l\ 14fl€flt iitn 7 7 , iri....r.r ti,itt q awitI isiSW16thSTD .y•. •.." i 1 14 i{ i= -\ It r t ; I iii TLk 4.:: -!''‘' k E„1 " ft.! i[,• r....+ ., s+++,_ •'„ 8 rmr.an €_E iJ •+c.1} 4'...41 SITE SOIL GROUPS r. ;i, T uta UR - URBAN LAND g \.. p 1ti"`y.." :K C ^•p .a` :..., Sy.: I r 01meg Yr ice1WO - WOODINVILLE SILT LOAM l\\\ PY - PUYALLUP FINE SANDY LO BNRR- _I NG - NEWBERG SILT LOAM z, I"x _ UPRR rf 00. 5011111114 NO gi ..:Ibi•- 01 ' 8 von. 41:1 Slit , III , !,,cili a ,1 rai-Ap,, _ y k1 II I AS- AHIGWWAiESTV4611GREENRIVER l GNM..1 IN A•..,11L era MOM Pi ns . . M Ifw. flYACCEPTM PRE-DEVELOPMENT DRAINAGE BASINS •••••-+• FIG. B.1SURFACEPROECTNA©E AENT ,0;t__AVAIEFACOr 01•002 ia:%son i OPAL)MASTER wMCArAES CATICE PARK I Boeing Commercial Airplane Group BCAG Headquarters Building 25-20 Site Development Area Weighted Runoff Coefficient Post-Development CSTC Drainage Basin A North Main Track Basin) Sub-Basin A-2 Soil Hydrologic Curve Land Use Area I Weight I Weighted Group Group Number Description sO Curve Number Ur I D 98 Building Roofs 392,512 1 14%13.56 Ur D 98 , Pavements 733,588 1 26% j 25.35 Ur 1 91 , Gravel Parking Lots 158,000 6% 5.07 Ur I 1 D 90 1 Landscaping(good)1 980,705 35% !31.12 Ur 1 D 90 Lawns(good) 380,501 13%12.07 Ur D 100 Water Surfaces 182,098 6% 6.42 Py B 80 Lawns(good) 8,978 0% 0.25 TOTALS I 2,836,382 I 100% 93.84 Notes: 1. Soil groups estimated from Soil Survey of King CountyArea, Washington, Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual, Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2E Impervious area(curve number>=98) 30.03 Acres Impervious area curve number 98.28 Pervious area (curve number<98) 35.08 Acres Pervious area curve number 90.04 Basin Composite Curve Number 93.84 BLsin Total Areal 65.11 Acres 013747/2210/engr/-Kbcalc16.xls[Post CSTC A-2] 9/11/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project (SWMP) Post-Development CSTC Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-2 Sheet Flow(4pplicable to rc only) Surface description (see Table 3.5.2C) asphalt parking Ipt s Manning's roughness coefficient, nSh 0 011 ' Flow length (Lk=300'),sheet 70 feet: 2-year,24-hogr rainfall, P2 2A00indhei Land slope, Sheet 0•00titt 1Ttsheet 0.02 hours 1 nTtsheet1.15 min Channel Flow, Section 1 Surface description (see Table 3.5.2C) concrete Pipe Flow length, Lchannel Watercourse ,lope, S channel 6,906 Factor, kc (see Table 3.5.2C) 42 Velocity, Vc,he1 3.0 f/s Tt channel 0.11 hours Tt channel 6.85 min Results:Basin A (Post-Development) Total Tc or Tt 0.13 hours Total Tc or Tt 8.00 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet!modified to conform with Section 3.5.2 of the King County Suiface Water Design Manual 013893/2220/engr-Kbcalc17.xls[Post-CSTC A-2] 9/11/98 Sverdrup Civil,Inc. 9/11/98 10 :43 :24 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST CSTC, BASIN A-2 BASIN SUMMARY BASIN I : AA-2-10 j NAME: BASIN A-2 POST CSTC, 10YR SBUH ME HODOLOGY I TOTAL EA 65 . 11 Acres BASEFLOWS: 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP . PRECIPI'ATION 2 . 90 inches AREA. . : 35 ..08 Acres 30 . 03 Acres TIME IN ERVAL 10 . 00 min CN 90 . 04 98 .28 TC 8 . 00 min 8. 00hmin ABSTRAC ION COEFF:I 0 .20 i` PEAK RA E: 38 .22 cfs VOL: 12 .30 Ac-ft TIME: 480 min II BASIN I : AA-2-100Ii NAME: BASIN A-2 POST CSTC, 100YR SBUH ME HODOLOGY TOTAL EA 65 .11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIP#ATION 3 . 90 inches AREA. . : 35 . 08 Acres 30 . 03 Acres TIME IN ERVAL • • 10 . 00 min CN 90 . 04 98 .28 TC • • 8 . 00 min 8 . 006min ABSTRAC ION COEFF: 0 .20 PEAK RA E: 54 . 58 cfs VOL: 17. 52 Ac-ft TIME: 480 min BASIN I : AA-2-2 • NAME: BASIN A-2 POST CSTC, 2YR SBUH ME HODOLOGY TOTAL EA 65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPI ATION 2 . 00 inches AREA. . : . 35 . 08 Acres 30 . 03 Acres TIME IN ERVAL , •] 10 . 00 min CN 90 . 04 98 . 28 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 23 . 74 cfs VOL: 7 . 72 Ac-ft TIME: 480 min BASIN I : AA-2-25i1 NAME: BASIN A-2 POST CSTC, 25YR SBUH ME HODOLOGY TOTAL EA i65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPI ATION j 3 .40 inches AREA. . : 35 . 08 Acres 30 . 03 Acres TIME IN ERVAL I 10 . 00 min CN 90 . 04 98 . 28 TC 8 . 00 min 8 . 006min ABSTRAC ION COEFF: 0 . 20 PEAK RA E: 46 .39 cfs VOL: 14 . 90 Ac-ft TIME: 480 min 9/11/98 10 :43 :2 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST CSTC, BASIN A-2 BASIN SUMMARY BASIN ID: AA-2-5 NAME: BASIN A-2 POST CSTC, 5YR SBUH METHODOLOGY TOTAL AREA 65 .11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE L KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 35 . 08 Acres 30 . 03 Acres ' _ TIME INTERVAL 10 . 00 min CN 90 . 04 98 .28 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF 0 .20 PEAK RATE: 30 . 12 cfs VOL: 9 . 74 Ac-ft TIME: 480 min BASIN ID: AA-2-50 NAME: BASIN A-2 POST CSTC, 50YR SBUH METHODOLOGY TOTAL AREA 65 . 11 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION: . . . : 3 .45 inches AREA. . : 35 . 08 Acres 30 . 03 Acres ,__. TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 28 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 47 .20 cfs VOL: 15 . 16 Ac-ft TIME: 480 min BASIN ID: AA-2-WQ NAME: BASIN A-2 POST CSTC, WQ SBUH METHODOLOGY TOTAL AREA 65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 35 . 08 Acres 30 . 03 Acres ,_ , TIME INTERVAL. . . . :: 10 . 00 min CN 90 . 04 98 .28 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 4 .41 cfs VOL: 1 . 62 Ac-ft TIME: 480 min I The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Post-Development CSTC Drainage Basin A Delta Area Basin) Sub-Basin A-3 Soil Hydrologic Curve Land Use Area Weight Weighted Group Group Number . Description sf) Curve Number Ur D ' 90 !Landscaping(good) 121,924 24%21.37 Ur D 100 . !Water Surfaces 42,836 8% 8.34 Ur D 91 1 Gravel Parking Lots 5,500 1% 0.97 Ur I C 87 ' !Sand Racing Track(dirt road) I 59,753 12%10.12 Ur D 92 ' Horse Walking Areas(fair) 16,739 3% 3.00 ' Py I B j 80 . Landscaping(good) 180,242 35%28.08 Py B 85 ' Gravel Parking Lots 22,966 4% 3.80 Py B 78 , Meadow 41,250 8% 6.27 Py B 80 ;Lawns(good) 1,347 0% 0.21 Py 1 B 100' Water Surfaces 20,956 4% 4.08 TOTALS I 1 1 513,513 100% 86.25 Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington,Des Moines Quadrangle 1973 2. Hydrologic roups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>=98) 1.46 Acres Impervious area curve number 100.00 Pervious area(curve number<98) 10.32 Acres Pervious area curve number 84.29 Basin Composite Curve Number 86.25 Basin Total Area' 11.79 Acres 013893/2220/engr/-Kbcalcl6.xls[Post-CSTC A-3] 9/11/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project (SWMP) Post-Development CSTC Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-3 Sheet Flow(Applicable to T c only) Surface description (see Table 3.5.2C) lawn:,:: Manning's roughness coefficient, nsheet Flow length (L<=300), Lsneet 200,fee# 2-year, 24-hour rainfall, P2 2.00 inches"":'; Land slope, Ssheet Ttsheet 0.36 hours Ttsheet 21.6 min Shallow Concentrated Flow Surface description (see Table 3.5.2C) brushy ground..Witf7somitrees;.•`, Flow length, Lsheilow Watercourse slope, Sshanow 0.060 ft/ft Factor, ks (see Table 3.5.2C) Velocity, Vshanow i 1.2 f/s Ttshallow 0.07 hours Tt shallow 4.4 min Results:Basin A (Post-Development) Total To or Tt 0.43 hours Total To or Tt 1 126.0 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalc17.xls[Post-CSTC A-3] 9/11/98 Sverdrup Civil,Inc. I I 1 9/11/98 10 :43 :37im Sverdrup Civil Inc page 1 THE BOEING COMPANY I SURFACE ATER MANAGEMENT PROJECT POST CST BASIN A 3 BASIN SUMMARY j , BASIN ID: AA-3-10 NAME: BASIN A-3 ,POST CSTC, 10YR SBUH MET ODOLOGY TOTAL AR A 11.78 Acres BASEFLOWS: '0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITr•TION 2 . 90 inches AREA. . : 10 .32 Acres 1 .46 Acres TIME INT RVAL 10 . 00 min . CN 84 .29 99 . 99 I TC 26 . 00 min 26 . 00 'min ABSTRACT ON COEFF: 0 .20 i ' PEAK RAT : 3 .43 ifs VOL: 1 . 60 Ac-ft TIME: 480 min BASIN ID: AA-3-100 NAME: BASIN A-3 POST CSTC, 100YR 1 1 SBUH METHODOLOGY I TOTAL AT: A 11. 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 10 .32 Acres 1 .46 Acres TIME INTERVAL 10 . 00 .min CN 84 . 29 99 . 99 TC 26 . 00 min 26 . 001min ABSTRACTION COEFF: 0 .20 PEAK RAT : 5 . 55 cfs VOL: 2 .46 Ac-ft TIME: ' 480 min BASIN ID: AA-3-2 NAME: BASIN A-3 POST CSTC, 2YR SBUH METHODOLOGY TOTAL ARIA 11. 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 10 . 32 Acres 1 .46 Acres TIME INTERVAL ' • 10 . 00 min CN 84 . 29 99 . 99 TC 26 . 00 min 26 . 00 ;min ABSTRACTION COEFF: 0 .20 PEAK RAT! : • 1 . 71 cfs VOL: 0 . 89 Ac-ft TIME: 480 min BASIN ID: AA-3-25 NAME: BASIN A-3 POST CSTC, 25YR SBUH MET ODOLOGY TOTAL ARIA 11 . 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE I KC24HR PERV IMP i PRECIPITATION I 3 .40 inches AREA. . : 10 . 32 Acres 1 .46 Acres 1 TIME INTERVAL 10 . 00 min CN 84 . 29 99 . 99 TC 26 . 00 min 26 . 00 .min ABSTRACTION COEFF: I 0 . 20 PEAK RAT! : 4 .47 cfs VOL: 2 . 02 Ac-ft TIME: 480 min Civil Inc page 219810 :43 :37 am Sverdrupp g9/1 / THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST CSTC, BASIN A-3 BASIN SUMMARY BASIN ID: AA-3-5 NAME : BASIN A-3 POST CSTC, 5YR SBUH METHODOLOGY TOTAL AREA 11 . 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches. . AREA. . : 10 .32 Acres 1 .46 Acres I ' TIME INTERVAL 10 . 00 min CN 84 .29 99 . 99 TC 26 . 00 min 26 . 00 min ABSTRACTION COEFF: 0 .20 I PEAK RATE: 2 .44 cfs VOL: 1.20 Ac-ft TIME: 480 min BASIN ID: AA-3-50 NAME: BASIN A-3 POST CSTC, 50YR SBUH METHODOLOGY TOTAL AREA 11 . 78 Acres • BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP I PRECIPITATION 3 .45 inches AREA. . : 10 . 32 Acres 1.46 Acres . _, TIME INTERVAL 10 . 00 min CN 84 .29 99 . 99 TC 26 . 00 min ' 26 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 4 . 58 cfs VOL: 2 . 07 Ac-ft TIME: 480 min BASIN ID: AA-3-WQ NAME: BASIN A-3 POST CSTC, WQ SBUH METHODOLOGY TOTAL AREA 11 :78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE L KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 10 . 32 Acres 1 .46 Acres TIME INTERVAL 10 . 00 min CN 84 . 29 99 . 99 TC 26 . 00 min 26 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 0 . 18 cfs VOL: 0 . 12 Ac-ft TIME : 480 min I__ Boeing Commercial Airplane Group BCAG Headquarters Building 25-20 Site Development Area Weighted Runoff Coefficient Post-Development Building 25-20 Drainage Basin A North Main Track Basin) Sub-Basin A-2 Soil hydrologic Curve Land Use Area Weight Weighted Group Group Number Description sf) Curve Number Ur D 98 Building Roofs 392,512 14%13.56 Ur D 98 Pavements 766,896 27%26.50 Ur D 91 Gravel Parking Lots 158,000 6% 5.07' Ur j D 90 , Landscaping(good) 947,397 33%30.06 Ur D 90 Lawns(good) 380,501 I 13%12.07 Ur D 100 Water Surfaces 182,098 6% 6.42 Py B 80 Lawns(good) 8,978 0% 0.25, TOTALS 2,836,382 I 100% I 93.94 Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington,Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual, Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>= 98) 30.80 Acres Irrtpervious area lcuve number 98.27 PI rvious area(curve number< 98) 34.32 Acres P rvious area curve number 90.05 Basin Composite Curve Number 93.94 Basin Total Area ,65.11 Acres II i 4 I 13747/2210/engr/-Kbcalcl6.xls[Post-2520 A-2] 9/11/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project (SWMP) Post-Development Building 25-20 Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-2 Sheet Flow(Applicable to T, only) Surface description (see Table 3.5.2C) asphalt parking(ot Manning's roughness coefficient, nsheet 0.011; Flow length (L =300'), Lsheet 70 feet2. 2-year, 24-hour rainfall, P2 2;04 inches; ". ; Land slope, Sslheet 0;020.ftlft Ttsheet 0.02 hours Ttsheet 1.15 min Channel Flow, Section 1 Surface description (see Table 3.5.2C) concrete.pipc.:, . Flow length, l-channel 1220 ft Watercourse slope, Schannel 0.00510t;': Factor, kc (see Table 3.5.2C) 42. : . I Velocity, Vchannel 3.0 f/s Ttchannel 0.11 hours Tt channel 6.85 min Results:Basin A (Post-Development) Total Tc or Tt 0.13 hours Total Tc or Tt 8.00 min Notes: 1. Worksheet'is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheetimodified to conform with Section 3.5.2 of the King County Su face Water Design Manual it 013893/2220/engr-Kbcalc17.xls[Post-2520 A-2]9/11/98 Sverdrup Civil,Inc. 9/11/98 10 :44 :10 am Sverdrup Civil Inc page 1 THE BOEING COMPANY II SURFACE WATER MANAGEMENT PROJECT i POST BL G 25-20, BASIN A-2 I. I I BASIN SUMMARY BASIN I : BA-2-10 NAME: BASIN A-2 POST 25-20, 10YR SBUH ME HODOLOGY TOTAL EA 65 .12 Acres BASEFLOWS : 0 . 00 cfs II RAINFAL TYPE i KC24HR PERV IMP PRECIPI ATION 2 . 90 inches AREA. . : • 34 . 32 Acres 30 . 80 Acres TIME IN ERVAL 10 . 00 min CN 90 . 05 98 . 27 TC 8 . 00 min 8 . 00 ' min ABSTRACTION COEFF: 0 .20 PEAK RATE: 38 .38 cfs VOL: 12 .35 Ac-ft TIME: 480 min BASIN II : BA-2-100' NAME: BASIN A-2 POST 25-20, 100YR SBUH METHODOLOGY TOTAL A ',EA 65 . 12 Acres • BASEFLOWS : ' 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . :. 34 .32 Acres 30 . 80 Acres TIME IN ERVAL 10 . 00 min CN 90 . 05 98 . 27 TC 8 . 00 min 8 . 00ilmin ABSTRAC ION COEFF:' 0 .20 PEAK RA E: 54 .73 cfs VOL: 17 .58 Ac-ft TIME: 480 min BASIN I : BA-2-2 NAME: BASIN A-2 POST 25-20, 2YR SBUH ME HODOLOGY TOTAL AlEA 65 . 12 Acres BASEFLOWS: 0 . 00 cfs RAINFAL TYPE I KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 34 . 32 Acres 30 . 80 Acres TIME IN ERVAL 10 . 00 min CN 90 . 05 98 .27 TC 8 . 00 min 8 . 00 min ABSTRAC ION COEFF: 0 . 20 PEAK RA E: 23 . 89 cfs VOL: 7. 77 Ac-ft TIME: 480 min BASIN I ' : BA-2-25 i . NAME : BASIN A-2 POST 25-20, 25YR SBUH METHODOLOGY TOTAL AREA 65 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPI ATION 3 .40 inches AREA. . : 34 .32 Acres 30 . 80 Acres TIME IN ERVAL j 10 . 00 min CN 90 . 05 98 . 27 TC 8 . 00 min 8 . 00ifmin ABSTRACTION COEFF: 0 .20 PEAK RATE: 46 .55 rcfs VOL: 14 . 95 Ac-ft TIME : 480 min I I_- j I' F I it 1 s 9/11/98 10 :44 :10 am Sverdrup .Civil Inc page 2 THE BOEING COMPANY ii SURFACE WATER MANAGEMENT PROJECT POST BLDG 25-20, BASIN A-2 BASIN SUMMARY I BASIN ID: BA-2-5 NAME: BASIN A-2 POST 25-20, 5YR SBUH METHODOLOGY TOTAL AREA 65 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 34 .32 Acres 30 . 80 Acres !_ TIME INTERVAL 10 . 00 min CN 90 . 05 98 .27 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 30 .28 cfs VOL: 9 . 78 Ac-ft TIME: 480 min BASIN ID: BA-2-50 NAME: BASIN A-2 POST 25-20, 50YR SBUH METHODOLOGY TOTAL AREA 65 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 34 .32 Acres 30 . 80 Acres TIME INTERVAL 10 . 00 min CN 90 . 05 98 .27 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF': 0 .20 PEAK RATE: 47. 36 cfs VOL: 15 .22 Ac-ft TIME: 480 min BASIN ID: BA-2-WQ NAME: BASIN A-2 POST 25-20, WQ SBUH METHODOLOGY TOTAL AREA i• 65 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE I• KC24HR PERV IMP PRECIPITATION I• 0 . 67 inches AREA. . : 34 .32 Acres 30 . 80 Acres TIME INTERVAL I• 10 . 00 min CN 90 . 05 98 .27 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 4 . 50 cfs VOL: 1 . 65 Ac-ft TIME: 480 min l j i i The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Post-Development Building 25-20 Drainage Basin A Delta Area Basin) Sub-Basin A-3 Soil Hydrologic Curve Land Use Area Weight Weighted Group Group Number Description sf) Curve Number Ur D 90 Landscaping(good) 121,924 24% 1 21.37 Ur D 10'0 Water Surfaces 42,836 8% 8.34 Ur j D I 91 ' 'Gravel Parking Lots 5,500 1% 0.97 Ur II C I 87 (Sand Racing Track(dirt road) ; 59,753 12% I 10.12 Ur 1 D 92 Horse Walking Areas(fair) 16,739 3% 3.00 Py B 80 Landscaping(good) 180,242 35% 28.08 Py B 85 I Gravel Parking Lots 22,966 4% 3.80 Py B 78 , Meadow 41,250 8% 6.27 Py B 80 Lawns(good) 1,347 0% 0.21 PY I 1 B I 100 Water Surfaces 20,956 4% 4.08 TOTALS i I I I 513,513 I 100% I 86.25 Notes: 1 . 1. Soil groups estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2E Impervious area(curve number>= 98) 1.46 Acres I pervious area curve number 100.00 Pervious area(curve number<98) 10.32 Acres Pervious area curve number 84.29 I Basin Composite Curve Number 86.25 Basin Total Areal 11.79 Acres I 0'3893/2220/engr/-Kbcalcl6.xls[Post-2520 A-3] 9/11/98 Sverdrup Civil,Inc. I The Boeing Company Surface Water Management Project (SWMP) i Post-Development Building 25-20 Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-3 Sheet Flow(Applicable to Tc only) Surface description (see Table 3.5.2C) lawn:,-- „ :'` ,:` . Manning's roughness coefficient, sheet Flow length (L<=300'), Lsneet 200 feef, ;: 2-year, 24-hour rainfall, P2 2.00 inches: ,:,„°„„ Land slope, Ssheei 0:020 ftfft:„:;'' Tt sheet 0.36 hours Ttsheet 21.6 min Shallow Concentrated Flow Surface description (see Table 3.5.2C) brushy grourid;with sorrie trees"":_ Flow length, Lshaliow 325 ft;;, Watercourse slope, Sshallow 0060 ; y°.:.` Factor, ks (see Table 3.5.2C) 5 ;:..: . Velocity, Vshallow 1.2 f/s Ttshallow 0.07 hours Ttshallow 4.4 min Results:Basin A (Post-Development) Total T,or Tt 0.43 hours Total T,or Tt 126.0 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 1 013893/2220/engr-Kbcalcl7.xls[Post1,2520 A-3]9/11/98 Sverdrup Civil,Inc. I I 9/11/98 10 :44 :28am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST BLIG 25-20, BASIN A-3 BASIN SUMMARY BASIN I : BA-3-10 ! NAME: BASIN A-3 POST 25-20, 10YR SBUH METHODOLOGY TOTAL AEA 11 . 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 10 . 32 Acres 1 .46 Acres TIME IN7ERVAL 10 . 00 min CN 84 . 29 99 . 99 TC 26 . 00 min 26 . 00Imin ABSTRACTION COEFF 0 .20 PEAK RA E: 3 .43 licfs VOL: 1. 60 Ac-ft TIME: 480 min BASIN I4 : BA-3-100 , NAME: BASIN A-3 POST 25-20, 100YR SBUH METHODOLOGY TOTAL AREA 11 . 78 Acres BASEFLOWS: 0 . 00 cfs. RAINFALL TYPE KC24HR PERV IMP PRECIPI ATION 3 . 90 inches AREA. . : 10 .32 Acres 1.46 Acres TIME IN ERVAL 10 . 00 min CN 84 . 29 99 . 99 TC 26 . 00 min 99 . 99 26 . 00 ABSTRAC I ION COEFF:i 0 . 20 II PEAK RATjE: 5 . 55 cfs VOL: 2 .46 Ac-ft TIME: 480 min BASIN ID: BA-3-2 ! NAME: BASIN A-3 POST 25-20, 2YR I SBUH METHODOLOGY TOTAL AREA 111 . 78 Acres BASEFLOWS: 0 . 00 cfs I RAINFALL TYPE KC24HR PERV IMP PRECIPITATION! 2 . 00 inches AREA. . : 10 . 32 Acres 1 .46 Acres TIME INTERVAL 10 . 00 min CN 84 . 29 99 . 99 TC 26 . 00 min 26 . 00 min ABSTRACTION COEFF:i 0 .20 PEAK RA]'E: 1 . 71 ;cfs VOL: 0 . 89 Ac-ft TIME: 480 min BASIN ID: BA-3-25 ' , NAME: BASIN A-3 POST 25-20, 25YR I SBUH METHODOLOGY I TOTAL AREA 11 . 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALLL TYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 10 : 32 Acres 1 .46 Acres TIME INTERVAL 10 . 00 min CN 84 . 29 99 . 99 TC 26 . 00 min 26 . 00 min ABSTRACTION COEFF 0 .20 I PEAK RATE: 4 .47. Hcfs VOL: 2 . 02 Ac-ft TIME: 480 min i 1 I 9/11/98 10 :44 :28 -am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE' WATER MANAGEMENT PROJECT POST BLDG 25-20, BASIN A-3 BASIN SUMMARY i BASIN ID: BA-3-5 NAME: BASIN A-3 POST 25-20, 5YR iI SBUH METHODOLOGY TOTAL AREA 11. 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP I ' PRECIPITATION 2 .40 inches AREA. . : 10 .32 Acres 1 .46 AcresL. TIME INTERVAL 10 . 00 min CN 84 .29 99 . 99 TC 26 . 00 min 26 . 00 min ,- ABSTRACTION COEFF: 0 .20 Ii, PEAK RATE: 2 .44 cfs VOL: 1 .20 Ac-ft TIME: 480 min BASIN ID: BA-3-50 NAME: BASIN A-3 POST 25-20, 50YR SBUH METHODOLOGY TOTAL AREA 11. 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION i• 3 .45 inches AREA. . : 10 .32 Acres 1.46 Acres ` _' TIME INTERVAL 10 . 00 min CN 84 .29 99 . 99 TC 26 . 00 min 26 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 4 . 58icfs VOL: 2 . 07 Ac-ft TIME: 480 min I BASIN ID: BA-3-WQI NAME: BASIN A-3 POST 25-20, WQ SBUH METHODOLOGY 1 TOTAL AREA 11 . 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 10 .32 Acres 1 .46 Acres , ! TIME INTERVAL I• 10 . 00 min CN 84 .29 99 . 99 TC 26 . 00 min 26 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 18 cfs VOL: 0 . 12 Ac-ft TIME: 480 min I Boeing Commercial Airplane Group Boeing Family Center Building 25-10 Site Development Area Weighted Runoff Coefficient Post-Development Building 25-10 Drainage Basin A North Main Track Basin) Sub-Basin A-2 ji Soil lfydrologic Curve I Land Use Area Weight Weighted Group Group Number Description s0 Curve Number Ur 1 D 98 I Building Roofs 392,512 14% I 13.561' Ur D 98 I Pavements 800,204 28% 27.651I Ur D 911 I Gravel Parking Lots 158,000 6% 5.07 I Ur D I 90 : I Landscaping(good) 947,397 33% 1 30.0611 Ur I D 90 Lawns(good) 347,193 12%11.021 Ur I D 100 Water Surfaces 182,098 6% 6.42 Py B I 98 I Pavements 8,978 0% 0.31 TOTALS I I 1 1 2,836,382 1 100% 1 94.09 Notes: 1 ' 1. Soil group estimated from Soil Survey of King County Area, Washington,Des Moines Quadrangle 1973 2. HydrologiC groups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve Nu bers determined from King County Surface Water Design Manual,Table 3.5.2B I ' Impervious area(curve number>=98) 31.77 Acres Impervious area curve number 98.26 Pervious area (curve number<98) 33.35 Acres Pervious area curve number 90.11 Basin Composite Curve Number 94.09 B sin Total Area 65.11 Acres I j II I I I I 013893/2220/engr/-Kbcalc16.xls[Post-2510 A-2] 9/11/98 Sverdrup Civil,Inc. I ii The Boeing Company Surface Water Management Project (SWMP) Pre-Development SWMP (Post-Development Building 25-10: Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-2 Sheet Flow(Applicable to T c only) Surface description (see Table 3.5.2C) asphalt"parking lot Manning's roughness coefficient, nsheet 0 011 -'" =,' ;= . _-,- Flow length (L<=300'), Lsheet 70 fleet i xF 2-year, 24-hour rainfall, P2 2:00 inches > , :` :> Land slope, Ssneet 0:020 ftlft Ttsheet 0.02 hours Tt sheet 1.15 min Channel Flow, Section 1 Surface description (see Table 3.5.2C) concrete Flow thlen 1220 ftlength, [-channel Watercourse slope, Schannel 0:005.ft/ft ..: Factor, kc(see Table 3.5.2C) Velocity, Vchannei 3.0 f/s Ttchannel 0.11 hours Ttchannel 6.85 min Results:Basin A (Post-Development)j Total Tc or Tt ! 0.13 hours Total Tc or Tt 8.00 min Notes: 1. Worksheets is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalcl7.xls[Post-2510 A-2]9/11/98 Sverdrup Civil,Inc. 9/11/98 10 :44 :46 am Sverdrup Civil Inc page 1 THE BOEING COMPANY 1 SURFACE ATER MANAGEMENT PROJECT POST BLDG 25-10, BASIN A-2 LI I I BASIN SUMMARY 1 1 BASIN ID : CA-2-10 NAME: BASIN A-2 POST 25-10, 10YR SBUH ME HODOLOGY TOTAL "EA 65 . 12 Acres BASEFLOWS: 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPI ATION 2 . 90 inches AREA. . : 33 .35 Acres 31 . 77 Acres TIME IN ERVAL 10 . 00 min CN 90 . 11 98 . 2E TC • • 8 . 00 min 8 . 00 min ABSTRAC ION COEFF: 0 .20 PEAK RA E: 38 . 62 cfs VOL: 12 .43 Ac-ft TIME: ' 480 min BASIN ID : CA-2-100 NAME: BASIN A-2 POST 25-10, 100YR 1 SBUH ME HODOLOGY TOTAL ,EA 65 . 12 Acres BASEFLOWS: 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPI ATION 3 . 90 inches AREA. . : 33 .35 Acres 31. 77 Acres TIME IN ERVAL 10 . 00 min CN 90 . 11 98 .26 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 54 . 97 cfs VOL: 17. 66 Ac-ft TIME: • 480 min BASIN ID : CA-2-2 NAME: BASIN A-2 POST 25-10, 2YR SBUH ME HODOLOGY TOTAL EA 65 . 12 Acres BASEFLOWS: 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPI ATION 2 . 00 inches AREA. . : 33 . 35 Acres 31 . 77 Acres TIME IN ERVAL 10 . 00 min CN 90 . 11 98 . 2 TC 8 . 00 min 8 . 00 min ABSTRAC ION COEFF: 0 .20 PEAK RA E : 24 . 12 cfs VOL: 7. 83 Ac-ft TIME: 480 min BASIN I : CA-2-25 NAME: BASIN A-2 POST 25-10, 25YR SBUH ME HODOLOGY TOTAL EA. . .. . . . . : 65 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPI ATION 3 .40 inches AREA. . : 33 .35 Acres 31 . 77 Acres TIME IN ERVAL • • 10 . 00 min CN 90 . 11 98 . 26 TC 8 . 00 min 8 . 00min ABSTRACTION COEFF: 0 . 20 PEAK RA E: 46 . 78 cfs VOL: 15 . 03 Ac-ft TIME: 480 min 1 1 II I 1 1 I 1 i 9./11/98 . 10 :44 :46 am Sverdrup Civil Inc page 2 ' : THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST BLDG 25-10, BASIN A-2 BASIN SUMMARY BASIN ID: CA-2-5 NAME: BASIN A-2 POST 25-10, 5YR 1 SBUH METHODOLOGY TOTAL AREA 65 . 12 Acres 'BASEFLOWS: 0 . 00 ,cfs RAINFALL TYPE KC24HR PERV IMP j ' PRECIPITATION 2 .40 inches AREA. . : 33 .35 Acres 31 . 77 Acres Li TIME INTERVAL 10 . 00 min CN 90 . 11 98 . 26 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 . 20 I . PEAK RATE: 30 .52icfs VOL: 9 . 86 Ac-ft TIME: 480 min BASIN ID: CA-2-50 NAME:' BASIN A-2 POST 25-10, 50YR SBUH METHODOLOGY J TOTAL AREA 65 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV ' IMP j PRECIPITATION 3 .45 inches AREA. . : 33 .35 Acres 31 . 77 Acres TIME INTERVAL 10 . 00 min CN 90 . 11 98 .26 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 If PEAK RATE: 47 . 60 cfs VOL: 15 .30 Ac-ft TIME: 480 min BASIN ID: CA-2-WQ NAME: BASIN A-2 POST 25-10, WQ SBUH METHODOLOGY TOTAL AREA 65 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP j ! PRECIPITATION 0 . 67 inches AREA. . : 33 . 35 Acres 31 . 77 Acres TIME INTERVAL 10 . 00 min CN 90 .11 98 . 26 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 4 . 62 cfs VOL: 1 . 68 Ac-ft TIME: 480 min j , 1 1 1 ii The Boeing Company Surface Water Management Project(SWMP) I Area Weighted Runoff Coefficient Post-Development Building 25-10 II II, Drainage Basin A Delta Area Basin) Sub-Basin A-3 Soil Hydrologic Curve Land Use Area Weight Weighted Group Group Number Description sf) Curve Number Ur D 90 Landscaping(good) 121,924 32% 28.83 Ur D 100 Water Surfaces 42,836 11%11.25 Py B 98 Pavements 5,248 1% 1.35j' Py ! B 80 Landscaping(good) 189,678 50%39.86 Py B I 10,0 Water Surfaces 20,956 6% 5.51 TOTALS I 380,642 I 100% (86.80 Notes: 1. Soil groups estimated from Soil Survey ofKing County Area, Washington,Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual, Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2E Impervious area((curve number>=98) 1.58 Acres l pervious area curve number 99.85 Pervious area(curve number<98) 7.15 Acres P rvious area curve number 83.91 Basin Composite Curve Number 86.80 Basin Total Areal '8.74 Acres II i i II 013893/2220/engr/-Kbcalcl6.xls[Post-2510 A-3] 9/11/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project (SWMP) Post-Development Building 25-10 Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-3 Sheet Flow(Applicable to T c only) Surface description (see Table 3.5.2C) lawn:< ,. Manning's roughn',ess coefficient, nsheet 0:15 Flow length (L<=300'), sheet 200:feet' 2-year, 24-hour rainfall, P2 2 00 inches .;; ;< '` Land slope, Ssheet 0 020 ff/ft: .7 Ttsneet 10.36 hours Ttsheet 21.6 min Shallow Concentrated Flow Surface description (see Table 3.5.2C) brushy grounii}with•aonie trees` ~" Flow length, L hallow 125 ft"; Watercourse slope, Sshallow 0060;ft/ft° ;'=. Factor, ks (see Table 3.5.2C) Velocity, Vshallow 11.2 f/s Ttshallow 10.03 hours Tt shallow 11.7 min Results:Basin A (Post-Development) Total Te or Tt 10.39 hours Total Tc or Tt j 23.3 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet medified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalc17.xls[Post-2510 A-3]9/11/98 Sverdrup Civil,Inc. 9/11/98 10 :45 :3 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST BLDG 25-10, BASIN A-3 BASIN SUMMARY BASIN ID: CA-3-10 NAME: BASIN A-3 POST 25-10, 10YR SBUH METHODOLOGY TOTAL AREA 8 . 74 Acres BASEFLOWS : 0 . 00 cfs RAINFALLTYPE KC24HR PERV IMP PRECIPIT TION 2 . 90 inches AREA. . : 7 . 15 Acres 1 . 59 Acres TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 .30 min 23 . 30 min ABSTRACTION COEFF: 0 .20 PEAK RAT, : 2 . 75 cfs VOL: 1. 23 Ac-ft TIME: 480 min BASIN ID: CA-3-100; NAME: BASIN A-3 POST 25-10, 100YR SBUH METHODOLOGY TOTAL AREA 8 . 74 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION I . 3 . 90 inches AREA. . : 7 . 15 Acres 1 . 59 Acres TIME INTERVAL I 10 . 00 min CN 83 . 91 99 . 85 TC 23 . 30 min 23 .30 min ABSTRACTION COEFF: 0 .20 PEAK RAT : 4 .39 cfs VOL: 1 . 87 Ac-ft TIME: 480 min BASIN ID: CA-3-2 I NAME: BASIN A-3 POST 25-10, 2YR SBUH METHODOLOGY TOTAL AREA 8 . 74 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 7 . 15 Acres 1 . 59 Acres TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 . 30 min 23 . 30 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 1 .43 cfs VOL: 0 . 70 Ac-ft TIME: 480 min BASIN ID: CA-3-25 NAME : BASIN A-3 POST 25-10, 25YR SBUH METHODOLOGY TOTAL AREA 8 . 74 Acres BASEFLOWS : 0 . 00 cfs RAINFALL1TYPE KC24HR PERV IMP PRECIPITAATION 3 .40 inches AREA. . : 7 . 15 Acres 1 . 59 Acres TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 .30 min 23 .30 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 3 .56 cfs VOL: 1. 55 Ac-ft TIME: 480 min 9/11/98 10 :45 :3am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST BLDG 25-10, BASIN A-3 BASIN SUMMARY BASIN ID: CA-3-5 NAME: BASIN A-3 POST 25-10, •5YR SBUH METHODOLOGY TOTAL AREA 8 . 74 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE L KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 7 . 15 Acres 1 . 59 Acres TIME INTERVAL 10 . 00 min CN-83 . 91 99 . 85 TC 23 . 30 min 23 .30 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 1. 99 cfs VOL: 0 . 93 Ac-ft TIME: 480 min BASIN ID: CA-3-50 NAME: BASIN A-3 POST 25-10, 50YR SBUH METHODOLOGY TOTAL AREA 8 . 74 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 7 . 15 Acres 1 . 59 Acres ! TIME INTERVAL. . . . : 10 . 00 min CN 83 . 91 99 . 85 TC 23 . 30 min 23 .30 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 3 . 64 cfs VOL: 1 .58 Ac-ft TIME: 480 min BASIN ID: CA-3-WQ NAME: BASIN A-3 POST 25-10, WQ SBUH METHODOLOGY TOTAL AREA 8 . 74 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION. . . . : 0 . 67 inches AREA. . : 7 . 15 Acres 1 . 59 Acres TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 .30 min 23 .30 min ABSTRACTION COEFFI: 0 .20 PEAK RATE: 0 . 21 cfs VOL: 0 . 11 Ac-ft TIME: 480 min The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient 1 Pre-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin 4-1 Soil Hydrologic Curve j Land Use Area Weight ' Weighted Group i Group I Number 1 Description sf) I Curve Number Ur D I 98 I Building Roofs 23,727 j 4% 3.92 Ur D I 98 ' Pavements 34,958 6% 5.78, Ur D 91 ' Gravel Parking Lots 85,727 14%13.16 Ur I C 87 ,Sand Racing Track(dirt road) ; 54,723 9% 8.03 Ur 1 D 90 Lawns 287,313 48% j 43.60 Ur D 92 Horse Walking Areas(fair) 83,525 14% ;12.96 Ur D 89 Meadow 23,041 4% 3.46 TOTALS I i ' I 593,014 I 100% 90.90 Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington,Des Moines Quadrangle 1973 2. Hydrologiq groups determined from King County Surface Water Design Manual, Figure 3.5.2A1 3. Curve NuTbers determined from King County Surface Water Design Manual,Table 3.5.2E Impervious area(curve number>= 98) 1.35 Acres Impervious area curve number 98.00 Pervious area(curve number<98) 12.27 Acres Pervious area curve number 90.12 Basin Composite Curve Number 90.90 Basin Total Area 13.61 Acres 1 I 1 0 3747/2210/engr/-Kbcalci 6.xls[Pre-Basin 4-1[1 9/10/96 Sverdrup Civil,Inc. I I The Boeing Company Surface Water Management Project(SWMP) Pre-Development SWMP Time of Concentration or Travel Time Drainage Basin 4 South Main Track Basin) Sub-Basin 4-1 Sheet Flow(Applicable to T, only) Surface description(see Table 3.5.2C) Bare Soils'•; Manning's roughness coefficient, nsheet 0.011 Flow length(L<=300'), Lsheet 60 feet 2-year,24-hour rainfall, P2 12.00 inches Land slope,Ssheet 0:033ft/ft:_ Tt sheet 0.01 hours Tt sheet1 min Shallow Concentrated Flow I Surface description(see Table 3.5.2C) Flow length,Lshallow 0 ft': Watercourse slope,S shallow 11000 ft/ft Factor, ks(see Table 3.5.2C) 0-:. Velocity, Vshallow 10.0 f/s Tt shallow 0.00 hours Tt shallow 10 min Channel Flow,Section 1 Surface description(see Table 3.5.2C) Concrete pipe"(n=0012) Flow length,jLchannel 1725 ft Watercourse slope, Schannel 0.004ft/ft. ` . : : . z. Factor, kc(see Table 3.5.2C) Velocity,Vchannel 2.5 f/s Tt channel i 0.19 hours Tt channel 112 min Results:Basin B Sub-Basin B1(Post-Development) Total Tc or Tt 0.21 hours Total TcorTt 12min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds,2nd Edition(Technical Release Number 55), US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 1 013893/2220/engr-Kbcalc17.xls[Pre-Basin,4-1] 9/3/98 Sverdrup Civil,Inc. 9/10/98 9 : 13 :39 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVEIIL,OPMENT BASIN- 4, SUB-BASIN 4-1 BASIN SUMMARY BASIN ID: P4-1-10 NAME: BASIN 4, SUB 4-1, PRE, 10YR 1 SBUH METHODOLOGY TOTAL AREA 13 . 62 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 12 .27 Acres 1 .35 Acres TIME INT RVAL 10 . 00 min CN 90 . 12 98 . 00 TC 12 . 00 min 12 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 6 . 63 cfs VOL: 2 .25 Ac-ft TIME: 480 min I ; BASIN IDI: P4-1-100' NAME: BASIN 4 , SUB 4-1, PRE, 100YR SBUH METHODOLOGY TOTAL AREA 13 . 62 Acres BASEFLOWS: 0 . 00 cfs RAINFALL1TYPE KC24HR PERV IMP PRECIPITiATION 3 . 90 inches AREA. . : 12 . 27 Acres 1 . 35 Acres TIME INTERVAL 10 . 00 min CN 90 . 12 98 . 00 TC 12 . 00 min 12 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 9 . 92 cfs VOL: 3 .31 Ac-ft TIME: 480 min BASIN It : P4-1-2 NAME: BASIN 4, SUB 4-1, PRE, 2YR SBUH METHODOLOGY ' TOTAL AREA 13 . 62 Acres BASEFLOWS : 0 . 00 cfs RAINFALIJ TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 12 . 27 Acres 1 .35 Acres TIME INTERVAL 10 . 00 min CN 90 . 12 98 . 00 TC 12 . 00 min 12 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 3 . 77 cfs VOL: 1 .33 Ac-ft TIME: 480 min BASIN ID: P4-1-25 NAME : BASIN 4, SUB 4-1, PRE, 25YR SBUH METHODOLOGY ' TOTAL AREA 13 . 62 Acres BASEFLOWS : 0 . 00 cfs RAINFALLi TYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 12 .27 Acres 1 . 35 Acres TIME INTERVAL 10 . 00 min CN 90 . 12 98 . 00 TC 12 . 00 min 12 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 8 .27 cfs VOL: 2 . 77 Ac-ft TIME: 480 min 9/10/98 9 :13 :39. am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT i ' PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-1 BASIN SUMMARY BASIN ID: P4-1-5 i NAME: BASIN 4, SUB 4-1, PRE, 5YR SBUH METHODOLOGY TOTAL AREA 7 13 . 62 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 12 .27 Acres 1 . 35 Acres ' TIME INTERVAL 10 . 00 min CN 90 . 12 98 . 00 TC 12 . 00 min 12 . 00 min ABSTRACTION COEFF 0 . 20 i , PEAK RATE: 5 . 02 cfs VOL: 1 . 73 Ac-ft TIME: 480 min BASIN ID: P4-1-50 NAME: BASIN 4, SUB 4-1, PRE, 50YR SBUH METHODOLOGY TOTAL AREA 13 . 62 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 12 .27 Acres 1 .35 Acres H TIME INTERVAL 10 . 00 min CN 90 . 12 98 . 00 TC 12 . 00 min 12 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 8 .44 cfs VOL: 2 . 83 Ac-ft TIME: 480 min BASIN ID: P4-1-WQ NAME: BASIN 4, SUB 4-1, PRE, WQ SBUH METHODOLOGY TOTAL AREA 13 . 62 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 12 .27 Acres 1 .35 Acres TIME INTERVAL 10 . 00 min CN 90 . 12 98 . 00 TC 12 . 00 min 12 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 30 cfs VOL: 0 . 19 Ac-ft TIME: 480 min i- I I I I The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Pre-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin 4-2 Soil b'ydrologic Curve! Land Use Area Weight Weighted Group Group Number Description sf) Curve Number Ur D 98 Building Roofs 4,000 I 1% 1.08 Ur D 98 ' Pavements 5,000 1% 1.35 Ur D 91 Gravel Parking Lots 27,275 8% 6.861 Ur C 87 , 'Sand Racing Track(dirt road) 1 39,648 11% f 9.53 Ur D 90 ILawns 208,686 58% 51.91, Ur D 92 Horse Walking Areas(fair) 60,517 17%15.39 Ur D I 89 ' MMeadow 16,694 5% 4.111 TOTALS I I I 361,820 100% 90.23 Notes: 1. Soil group estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrologicgroups determined from King County Surface Water Design Manual, Figure 3.5.2A 3. Curve Nunbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>=98) 0.21 Acres Impervious area curve number 98.00 P rvious area(curve number<98) 8.10 Acres Pervious area curve number 90.04 Basin Composite Curve Number 90.23 Basin Total Area; 8.31 Acres li 013747/2210/engr/-Kbcalcl6.xls[Pre-Basin 4-2] 9/10/98 Sverdrup Civil,Inc. I The Boeing Company Surface Water Management Project(SWMP) Pre-Development SWMP • Time of Concentration or Travel Time Drainage Basin 4 South Main Track Basin) Sub-Basin 4-2 Sheet Flow(Applicable to T,only) Surface description(see Table 3.5.2C) Shortgressprarie: Manning's roughness coeftident,rtd,, 015 Flow length(L<=300'),Lg,, 150 feet 2-year.24-hourrainfall,P2 2.00inches - •- •- - Land slope,Sd„d 0.003Rift..: T,dw„; 0.59 hours T,d,,,,j 35 min Shallow Concentrated Flow Surface description(see Table 3.5.2C) 8rushyr grelmd with some trees 0=0.060) Flow length,Ly ,,, 100ft Watercourse slope,Sd a,, 0,002ff/ft " Factor;k,(see Table 3.5.2C) 5. - - -• Velocity,V,i„m„ 0.2 Us T,dww: 0.14 hours T,d dw 9 min Channel Flow,Section 1 Surface description(see Table 3.5.2C) Earth lined Waterway(n.025) Flow length,L,i,,,a 1050 fb.' Watercourse slope,Sd,,,,,, 0.017f1At Factor;k,(see Table 3.5.2C) Velocity,Vd,,,,,,d 2.6f/s 0.11 hours T,d,„;I 7min Channel Flow,Section 2 Surface description(see Table 3.5.2C) Concrete pipe(n--0012), • Flow length,Ld,,,,,d 127.0 ft Watercourse slope,Sd,,,,,,, 0.0061t/ft Factor!ke(see Table 3.5.2C) 42 Velocity,Vd,,,,,,, 3.3 Us Trchannel 0.01 hours T,d,,,,,e, 10.65 min 1 Channel Flow,Section 3 Surface description(see Table 3.5.2C) Grassed waterway(m-0.025) Flow length,ld,,,,,,, 540.0ft Watercourse slope,Se..., 0.005ft/ft Factor;k,(see Table 3.5.2C) 117 Velocity,Vd,,,,, 1.1 f/s d,a„it 0.13 hours T,d„nnt'm 7.89 min Channel Flow,Section 4 Surface description(see Table 3.5.2C) CMP pipe(n=0.024) Flow length,Ld,,,„N 60.0ft• Watercourse slope,Sd,,a 0.003ft/ft Factor;ke(see Table 3.5.2C) 21 Velocity,Vd,,,,,,, 1.1 Ifs 0.01 hours T,d,,,,;, 0.90 min Results:Basin B Sub-Basin B2(Post-Development) Total T,or T,11.00 hours Total Tc orT,160 min Notes: 1.Worksheet is based on Urban Hydrology forSmall Watersheds,2nd Edition(Technical Release Number 55),US SCS,1986 2.Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalc17.xrs:Pre-Basin 4-2i I 9/3/9B Sverdrup Civll,Inc. i 9/10/98 9 : 13 : 54 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-2 BASIN SUMMARY 1 BASIN ID: P4-2-10i NAME: BASIN 4, SUB 4-2, PRE, 10YR SBUH METHODOLOGY TOTAL AllEA 8 .31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 8 . 10 Acres 0 . 21 Acres TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF:: 0 . 20 PEAK RATE: 2 . 15 cfs VOL: 1.33 Ac-ft TIME: 490 min I I BASIN ID: P4-2-100 NAME: BASIN 4, SUB 4-2, PRE, 100YR SBUH METHODOLOGY ; TOTAL AREA 8 .31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 8 . 10 Acres 0 .21 Acres TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 0CY min ABSTRACTION COEFF:' 0 .20 PEAK RATE: 3 . 30 cfs VOL: 1. 97 Ac-ft TIME: 490 min BASIN ID: P4-2-2 1 ' NAME: BASIN 4, SUB 4-2, PRE, 2YR SBUH METHODOLOGY TOTAL AREA 8 . 31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 8 . 10 Acres 0 .21 Acres TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF:, 0 . 20 PEAK RATE: 1 . 16 cfs VOL: 0 . 77 Ac-ft TIME: 490 min i BASIN ID: P4-2-251 NAME: BASIN 4 , SUB 4-2, PRE, 25YR SBUH METHODOLOGY TOTAL AREA 8 . 31 Acres BASEFLOWS : 0 . 00 cfs RAINFALLL TYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 8 . 10 Acres 0 .21 Acres TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 2 . 72 'cfs VOL: 1. 65 Ac-ft TIME: 490 min 9/10/98 9 :13 :54 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-2 BASIN SUMMARY BASIN ID: P4-2-5 NAME: BASIN 4, SUB 4-2, PRE, 5YR SBUH METHODOLOGY TOTAL AREA 8 .31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 8 . 10 Acres 0 . 21 Acres TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 1 . 59Hfs VOL: 1 . 01 Ac-ft TIME: 490 min BASIN ID: P4-2-501 NAME: BASIN 4, SUB 4-2, PRE, 50YR SBUH METHODOLOGY I TOTAL AREA 8 . 31 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 8 . 10 Acres 0 .21 'Acres TIME -INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 2 . 781cfs VOL: 1 . 68 Ac-ft TIME: 490 min BASIN ID: P4-2-WQ1 NAME: BASIN 4, SUB 4-2, PRE, WQ SBUH METHODOLOGY TOTAL AREA 8 . 31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION L 0 . 67 inches AREA. . : 8 . 10 Acres 0 .21 Acres ; TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 08Icfs VOL: 0 . 10 Ac-ft TIME: 760 min 1 I The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Pre-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin 4-3 Soil ' Hydrologic Curve Land Use Area Weight Weighted Group Group Number Description sf) Curve Number Ur D 98 . 1 Building Roofs 1 11,011 3% 2.98 Ur D 98 , Pavements 1 14,109 4% 3.82. Ur D 91 1 Gravel Parking Lots 60,755 17%15.26 Ur C 87 ,Sand Racing Track(dirt road) 25,700 I 7% 6.17 Ur D 90 !Lawns 170,000 47% 1 42.23 Ur D 92 1 Horse Walking Areas(fair) 53,860 15%13.68 Ur 1 1 D 89 !Meadow 1 26,859 1 7%1 6.60 TOTALS I I I I I 362,294 100% I 90.73 Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface WaterDesign Manual,Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>=98) 0.58 Acres Impervious area curve number 98.00 Pervious area(curve number< 98) 7.74 Acres Pervious area curve number 90.19 Basin Composite Curve Number 90.73 Basin Total Area 8.32 Acres 13893/2220/en r/-Kbcalc16.xls[Pre-Basin 4-3] 9/3/98 Sverdrup Civil,Inc.9 The Boeing Company Surface Water Management Project(SWMP) Pre-Development SWMP Time of Concentration orTravel Time Drainage Basin 4 South Main Track Basin) Sub-Basin 4-3 f I Sheet Flow(Applicable to T,only) Surface description(see Table 3.5.2C) (Bale soli Manning's roughness coefficient,n,,,,d 10.011 • ;• - Flow length(L<=300'),Ld,.,, 180 feet.:.:,-_ .' 2-year,24-hour rainfall,P2 2.00inches- • Land slope, T,a„e„ 10.02 hours T,dad 11 min Shallow Concentrated Flow Surface description(see Table 3.5.2C) Flow length, Watercourse slope,Sd a, 44000,000fUR, Factor,k,(see Table 3.5.2C) Velocity,Va„a,,, 12307.4 f/s T,d,a„o„ 0.00 hours T,shallow. 0 min Channel Flow,Section 1 Surface description(see Table 3.5.2C) Grassed waterway-(nmo.025) Flow length,Le, 0 830 ft ; ' Watercourse slope,Sd,,,,d 0.005 tuft, ,1 Factor,Ico(see Table 3.5.2C) 1Z • Velocity,Vd,,,,,,1 1.2 f/s TIcha,,,el 0.19 hours Ti channel 112 min I i I Channel Flow,Section 2 Surface description(see Table 3.5.2C) (CMP pipe(rr0.024) 1 • Flow length,ld,,,- 17.0R Watercourse slope, Factor,k,(see Table 3.5.2C) I21 •. Velocity,Vda,,,,,, 2.5 f/s T,channel 10.00 hours T 10.11 minUennel Channel Flow,Section 3 Surface description(see Table 3.5.2C) Grassed waterway(n=0,025)- Flow length.1. ,,,„,r Watercourse slope,Sm„„,e, 0.005ft/tt'.• Factor,k,(see Table 3.5.2C) 17,.,, Velocity,Vd,,,n„, 11.1 f/s T,channel 10.14 hours T,channel 18.26 min Channel Flow,Section 4 Surface description(see Table 3.5.2C) ICMP pipe(n ).024)• Flow length, 160.0 R : Watercourse slope,Sd,,,,,a, 10.003(flit Factor,ko(see Table 3.5.2C) j21. Velocity,Vc„,,,, 11.1 f/s T,d,a,„,el 0.01 hours 7,m,,,1 10.90 min Results:Basin B Sub-Basin B3(Post-Development) Total Toor T,10.36 hours Total To orT,122 min Notes: 1.Worksheet is based on Urban HydrologyforSmall Watersheds,2nd Edition(Technical Release Number 55),US SCS,1986 2.Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalcl7.:ls[Pre-Basin 4-31 9/3/98 Sverdrup CMI,Inc. 9/3/98 3 :32 : 13 pm , Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-3 BASIN SUMMARY BASIN ID: P4-3-10 NAME: BASIN 4, SUB 4-3 , PRE, 10YR SBUH METHODOLOGY TOTAL AREA 8 .32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF:; ' 0 . 20 PEAK RATE: 3 . 39 ;cfs VOL: 1. 36 Ac-ft TIME : 480 min BASIN ID: P4-3-100 NAME : BASIN 4, SUB 4-3 , PRE, 100YR SBUH METHODOLOGY TOTAL AREA 8 .32 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RA E: 5 . 11 'cfs VOL: 2 . 01 Ac-ft TIME: 480 min BASIN I : P4-3-2 NAME: BASIN 4 , SUB 4-3, PRE, 2YR SBUH METHODOLOGY TOTAL AREA 8 .32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE 1 KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RA E: 1 . 90 cfs VOL: 0 . 80 Ac-ft TIME: 480 min BASIN I : P4-3-25 ' NAME: BASIN 4, SUB 4-3 , PRE, 25YR SBUH METHODOLOGY TOTAL AREA 8 . 32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME IN ERVAL 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRAC'h'ION COEFF: 0 .20 i PEAK RATE: 4 . 25 cfs VOL: 1 . 68 Ac-ft TIME : 480 min I. 1 9/3/9.8 3 :32 :13 pm Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-3 IBASINSUMMARY BASIN ID: P4-3-5 NAME: BASIN 4, SUB 4-3 , PRE, 5YR 1 SBUH METHODOLOGY TOTAL AREA 8 .32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP 1 , PRECIPITATION 2 .40 inches . AREA. . : 7 . 74 Acres 0 . 58 Acres ,__ TIME INTERVAL 10 . 00 min CN.90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE : 2 . 551cfs VOL: 1 . 04 Ac-ft TIME: 480 min I BASIN ID: P4-3-50 NAME: BASIN 4, SUB 4-3, PRE, 50YR SBUH METHODOLOGY TOTAL AREA 8 . 32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE i• KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 7 . 74 Acres . 0 . 58 Acres TIME INTERVAL. . . .: 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 .20 1 PEAK RATE : 4 .33 cfs VOL: 1 . 72 Ac-ft TIME: 480 min BASIN ID: P4-3-WQ NAME: BASIN 4, SUB 4-3, PRE, WQ SBUH METHODOLOGY TOTAL AREA 8 . 32 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL. . . . : 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE : 0 . 13 cfs VOL: 0 . 11 Ac-ft TIME: 490 min The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Pre-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin 4-4 Soil Hydrologic Curve Land Use Area Weight ' Weighted Group Group Number ; . Description i (sf) Curve Number Ur I D I 98 I Building Roofs I 112,162 6%i 5.55! Ur D 98 ' Pavements 145,456 7%j 7.20 Ur D 91 , Gravel Parking Lots i 227,644 11%10.46 Ur ' • C i 87 I Sand Racing Track(dirt road) 145,315 7% 6.38 Ur D 90 ' 'Lawns I 762,945 39% j 34.68 Ur D 92 I Horse Walking Areas(fair) 221,796 11%10.30 Ur I D 89 Meadow 61,185 3% 2.75 Wo D 98 Pavements I 9,549 0% 0.0 Wo D 91 , IGravel Parking Lots 35,991 2% 1.65 Wo D 92 'Lawns 143,065 7% 6.65 Ng B 98 , Pavements 17,052 1% 0.84 Ng B 85 , I Gravel Parking Lots 9,447 0% 0.41 Ng B I 85 ;Lawns(fair) 88,534 j 4% 3.80 TOTALS 1 ; ; 1 1 1,980,141 ; 100% 91.15 Notes: i i 1. Soil groups estimated from 8oiliSurveyof King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>=98) 6.52 Acres Impervious areal.curve number 98.00 Plervious area(curve number<98) 38.93 Acres Pervious area curve number 90.00 asin Composite Curve Number 91.15 asin Total Area 45.46 Acres v 13893/2220/engr/-Kb alcl6.xls[Pre-Basin 4-4] 9/3/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project(SWMP) Pre-Development SWMP Time of Concentration or Travel Time Drainage Basin 4 South Main Track Basin) Sub-Basin 4-4 Sheet Flow(Applicable to T. only) Surface description(see Table 3.5.2C)Short.grass prarie Manning's roughness coefficient,nsheet 0.15 Flow length(L<=300'),Lsheet 300 feet,. ',., 2-year,24-hour rainfall,P2 2.00'inches Land slope,Ssheet 0.017•ft/ft •• • Ttsheet 1 0.53 hours Tt sheet 1 132 min Shallow Concentrated Flow Surface description(see Table 3.5.2C)Short grass'„, Flow length,Lshalbw 1000 it., Watercourse slope,Sshalbw 0.005 ftfft Factor,ks(see Table 3.5.2C) 11• Velocity,Vshallow 0.8 f/s Tt shallow' 0.36 hours Tt shallow 21 min Channel Flow,Section 1 Surface description(see Table 3.5.2C)Concrete Pipe'(n=0.012) Flow length,Lchannet 710 ft , Watercourse slope,Sct,ennet 0.008 tuft Factor,!kc(see Table 3.5.2C) 42 Velocity,Vchannel 3.8 f/s Tt channel 0.05 hours Tt channel 3 min Channel Flow,Section 2 Surface description(see Table 3.5.2C)Concrete Pipe(n=0.012)•. • Flow length,Lchannel 40.0"ft; Watercourse slope,Schannel 0.014 ft/ft Factor,!kc(see Table 3.5.2C) 42" Velocity,Vchannel 5.0 f/s Tt channel 0.00 hours Tt channel 10.13 min Results:Basin B Sub-Basin B4(Post-Development) Total Ti or Tt 0.95 hours Total Ti or Tt 57 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds,2nd Edition(Technical Release Number 55),US SCS,1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalcl7.xls[Pre-Basin 4-4] 9/3/98 Sverdrup Civil,Inc. 9/3/98 3 :34 :21 pm Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE AIATER MANAGEMENT PROJECT PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-4 BASIN SUMMARY BASIN ID: P4-4-10 , NAME: BASIN 4, SUB 4-4, PRE, 10YR SBUH METHODOLOGY ' TOTAL AREA 45 .45 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 38 . 93 Acres 6 . 52 Acres TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 TC 57 . 00 min 57 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RAT : 12 . 67 cfs VOL: 7 . 59 Ac-ft TIME: 490 min BASIN ID: P4-4-100 NAME: BASIN 4, SUB 4-4, PRE, 100YR SBUH MET ODOLOGY TOTAL AREA 45 .45 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 38 . 93 Acres 6 . 52 Acres TIME INTiERVAL 10 . 00 min CN 90 . 00 98 . 00 TC 57 . 00 min 57 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 19 . 09 cfs VOL: 11 . 15 Ac-ft TIME: 490 min BASIN ID: P4-4-2 NAME : BASIN 4, SUB 4-4, PRE, 2YR SBUH MET ODOLOGY TOTAL AR A 45 . 45 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 38 . 93 Acres 6 . 52 Acres TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 TC 57 . 00 min 57 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE : 7 . 13 cfs VOL: 4 . 51 Ac-ft TIME: 490 min BASIN ID: P4-4-25 I NAME: BASIN 4 , SUB 4-4, PRE, 25YR I SBUH METHODOLOGY TOTAL AkEA 45 .45 Acres BASEFLOWS : 0 . 00 cfs RAINFALLfTYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 38 . 93 Acres 6 . 52 Acres TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 TC 57 . 00 min 57 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 15 . 86 cfs VOL: 9 . 36 Ac-ft TIME: 490 min 1 9/3/98 3 :34 :21 .pm Sverdrup Civil Inc page 2 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-4 IBASINSUMMARY 1 BASIN ID: P4-4-5 ' NAME: BASIN 4, SUB 4-4, PRE, 5YR SBUH METHODOLOGY 1 TOTAL AREA 45 .45 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION. . . .;: 2 .40 inches AREA. . : 38 . 93 Acres 6 . 52 Acres TIME INTERVAL. . . . 1: 10 . 00 min CN 90 . 00 98 . 00 j TC 57 . 00 min 57 . 00 min ABSTRACTION COEFFI: 0 . 20 PEAK RATE: 9 .541cfs VOL: 5 . 86 Ac-ft TIME: 490 min BASIN ID: P4-4-501 NAME : BASIN 4, SUB 4-4, PRE, 50YR SBUH METHODOLOGY TOTAL AREA 1• 45 .45 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . .,: KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 38 . 93 Acres 6 . 52 Acres ' TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 1 TC 57 . 00 min 57 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 16 .181cfs VOL: 9 . 54 Ac-ft TIME: 490 min 1 BASIN ID: P4-4-WQj NAME : BASIN 4, SUB 4-4, PRE, WQ SBUH METHODOLOGY 1 TOTAL AREA 1• 45 .45 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE r KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 38 . 93 Acres 6 . 52 Acres TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 TC 57 . 00 min 57 . 00 min ABSTRACTION COEFF,: 0 . 20 PEAK RATE: 0 . 63 cfs VOL: 0 . 68 Ac-ft TIME: 520 min I I I ' The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Pre-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin 4-5 Soil Hydrologic Curare;Land Use Area Weight Weighted Group Group Number , Description sfl I Curve Number Ur D I 98 1Building Roofs I 67,900 14%13.84 Ur D 98 . Pavements 314,271 65% 64.07 Ur D 90 , Landscaping(good) 98,495 20%18.44 TOTALS ;I 480,666 1 100% 1 96.36 Notes: I , 1. Soil groups estimated from Soil Survey of King County Area, Washington,Des Moines Quadrangle 1973 2. Hydrologic(groups determined from King County Surface Water Design Manual, Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2E Impervious area(curve number>=98) 8.77 Acres It ipervious area curve number 98.00 Pervious area(curve number<98) 2.26 Acres Pervious area curve number 90.00 B sin Composite Curve Number 96.36 B1•sin Total Area 11.03 Acres I I I I i I f I I i ,a 13747/2210/engr/-Kb alcl6.xls[Pre-Basin 4-5,j 9/10/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project(SWMP) Pre-Development SWMP Time of Concentration or Travel Time Drainage Basin 4 South Main Track Basin) Sub-Basin 4-5 Sheet Flow(Applicable to To only) Surface description(see Table 3.5.2C) lAsphalt Manning's roughness coefficient, nsheet 0.011 Flow length(L<=300'), Lsheet 75 feet 2-year,24-hour rainfall, P2 2.00'inches I Land slope,Ssheet 0.005 ft/ft . Tt sheet 0.04 hours Tt sheet 2 min Shallow Concentrated Flow Surface description(see Table 3.5.2C) Flow length,-shallow Oft Watercourse slope,S shallow 0.000 Mt: Factor, ks(see Table 3.5.2C) Velocity,Vshellow 0.0 f/s Tt shallow 0.00 hours Ttshallow 0 min Channel Flow, Section 1 Surface description(see Table 3.5.2C) Concrete pipe.(n=0012), Flow length,,Lchw,nel 1575 ft. ..• Watercourse;slope, S channel 10.004ft/ft'•` Factor, kc(see Table 3.5.2C) 42 Velocity,Vchannel 2.5 f/s Tt channel j 0.18 hours Ttchannel j 11 min Results:Basin B Sub-Basin B2520(Post-Development) Total Tc or T{0.21 hours Total To or T, 113 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds,2nd Edition(Technical Release Number 55),US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual i 013893/2220/engr-Kbcalcl7.xls[Pre-Basin 4-51 9/3/98 Sverdrup Civil,Inc. i 9/10/98 9 :25 :15 am Sverdrup Civil Inc page 1 II THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVDLOPMENT BASIN 4,, SUB-BASIN 4-5 BASIN SUMMARY I I BASIN ID : P4-5-10 NAME: BASIN 4, SUB 4-5, PRE, 10YR SBUH METHODOLOGY TOTAL EA 11. 03 Acres BASEFLOWS : 0 . 00 cfs II RAINFAL TYPE j . KC24HR - PERV IMP PRECIPI'IfATION 2 . 90 inches AREA. . : 2 .26 Acres 8 . 77 Acres TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 ABSTRAC ION COEFF: 0 .20 TC 13 . 00 min 13 . 00Imin i PEAK RA E: 6 . 68 cfs VOL: 2 .31 Ac-ft TIME: 480 min BASIN I : P4-5-100 NAME: BASIN 4, SUB .4-5, PRE, 100YR Id, SBUH METHODOLOGY j TOTAL AREA 11 . 03 Acres BASEFLOWS : 0 :00 cfs 1 RAINFALL TYPE VI KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 2 .26 Acres 8 . 77 Acres TIME IN ERVAL 10 . 00 min CN 90 . 00 98.. 00 TC 13 . 00 min 13 . 00 'min ABSTRAC ION COEFF: 0 .20 PEAK RA E: 9 .25 cfs VOL: 3 . 21 Ac-ft TIME: 480 min BASIN I : P4-5-2 NAME: BASIN 4, SUB 4-5, PRE, •2YR SBUH ME HODOLOGY TOTAL EA 11. 03 Acres BASEFLOWS : 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPI ATION 2 . 00 inches AREA. . : 2 .26 Acres 8 . 77 Acres TIME IN ERVAL 10 . 00 min CN 90 . 00 98 . 00 TC 13 . 00 min 13 . 00 min ABSTRACTION COEFF:,I 0 .20 PEAK RA E: 4 . 37Icfs VOL: 1 . 50 Ac-ft TIME: 480 min BASIN I : P4-5-25 NAME: BASIN 4, SUB 4-5, PRE, .25YR I SBUH ME HODOLOGY I TOTAL EA 11 . 03 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 2 .26 Acres 8 . 77 Acres TIME IN ERVAL I ; 10 . 00 min CN 90 . 00 98 . 00 TC 13 . 00 min 13 . 00 min ABSTRAC ION COEFF: i 0 .20 PEAK RA E: 7 . 96 cfs VOL: 2 . 76 Ac-ft TIME : 480 min I I I , it 1 9/10/98. 9 :25 :15 am Sverdrup Civil Inc page 2 ___ THE BOEING COMPANY ' , SURFACE WATER MANAGEMENT PROJECT iI PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-5 BASIN SUMMARY , I BASIN ID: P4-5-5 I NAME: BASIN 4, SUB 4-5, PRE, 5YR jf SBUH METHODOLOGY TOTAL AREA 11 . 03 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 2 .26 Acres 8 . 77 Acres ' _! TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 1 TC 13 . 00 min 13 . 00 min ABSTRACTION COEFF 0 .20 1 PEAK RATE: 5 .40icfs VOL: 1 . 86 Ac-ft TIME: 480 min BASIN ID: P4-5-50 NAME: BASIN 4, SUB 4-5, PRE, 50YR SBUH METHODOLOGY ! i ' TOTAL AREA 7 11. 03 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE 1. KC24HR PERV IMP I PRECIPITATION 3 .45 inches AREA. . : 2 .26 Acres 8 . 77 Acres , TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 i TC 13 . 00 min 13 . 00 min i ABSTRACTION COEFF1: 0 .20 PEAK RATE: 8 . 09Icfs VOL: 2 . 80 Ac-ft TIME: 480 min BASIN ID: P4-5-WQ1 NAME: BASIN 4, SUB 4-5, PRE, .WQ fl SBUH METHODOLOGY i TOTAL AREA 1• 11 . 03 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . I: KC24HR PERV IMP PRECIPITATION I: 0 . 67 inches AREA. . : 2 . 26 Acres 8 . 77 Acres } ; TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 00 j TC 13 . 00 min 13 . 00 min , , ABSTRACTION COEFFI: 0 . 20 PEAK RATE: 1 . 051cfs VOL: 0 . 37 Ac-ft TIME: 480 min i 1 j 1 I I j Ii I I I 1 1 1 I d I The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Pre-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin 4-6 Soil ydrologic Curve Land Use Area Weight Weighted Group Group Number Description sf)Curve Number Py B 98 ; ' Building Roofs 22,000 12% I 11.78 Py B 98 j Pavements 59,633 33% i 31.94 Py B 90 Lawns 35,369 19%17.40 Py I B 80 Landscaping(good) 47,464 26% j 20.75 Py B 100 Water Surfaces 5,860 3% 3.20' Py 1 B i 78 Meadow I 12,662 7% 5.40 TOTALS I 1 I 182,988 I 100% 90.46 Notes: 1. Soil groups estimated from SoilSurvey of King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve Numbers determined rot King County Surface Water Design Manual,Table 3.5.2E Impervious area(curve number>= 98) 2.01 Acres Impervious area curve number 98.13 PIrvious area(ciurve number<98) 2.19 Acres Pervious area curve number 83.44 asin Composite Curve Number 90.46 Basin Total Area 4.20 Acres I 1 I I I 1 013893/2220/engr/-Kbcalc16.xls[Pre-Basin 4-6] ' 9/3/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project(SWMP) Pre-Development SWMP Time of Concentration or Travel Time Drainage Basin 4 South Main Track Basin) Sub-Basin 4-6 Sheet Flow(Applicable to Tc only) Surface description(see Table 3.5.2C)Short-grass prarie Manning's roughness coefficient,nsheet 0.15., Flow length(L<=300'),Lsheet 25 feet '. 2-year,24-hour rainfall,P2 2.00 inches• • Land slope,Ssheet 0.030"ft/ft'' Tt sheet j 10.06 hours I I Tt sheet 1 13 min Shallow Concentrated Flow Surface description(see Table 3.5.2C) Flow length,Lshallow 0 ft Watercourse slope,Sshatbw 44000.000 ft/ft Factor,ks(see Table 3.5.2C) 11 " Velocity,Vshaibw 12307.4 f/s Tt shallow) 0.00 hours Ttshatbwj 0 min t i I Channel Flow,Section 1 Surface description(see Table 3.5.2C)Concrete pipe' Flow length,L channel 575 ft Watercourse slope,Schannei 0.005 ft/ft Factor,Ikc(see Table 3.5.2C) 42' Velocity,Vchannei 13.0 f/s Ttchannei 10.05 hours Tt channel 13 min Channel Flow,Section 2 Surface description(see Table 3.5.2C)CMP pipe(n=0.024) Flow length,I-channel 55.0 ft„ Watercourse slope,Schannei 0.002 Mt Factor,jkc(see Table 3.5.2C) 21 Velocity,Vchannei 10.9 f/s Tt channel10.02 hours Tt channel 0.98 min Results:Basin B Sub-Basin B3(Post-Development) Total TL or Tt 0.13 hours Total Tic or Tt 18 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds,2nd Edition(Technical Release Number 55),US SCS,1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalc17.xls[Pre-Basin 4-6] 9/3/98 SverdrupCivil,Inc. I 1 II a9/3/98 3 :37 : 54 pml Sverdrup Civil Inc page, 1 I THE BOEING COMPANY SURFACE ATER MANAGEMENT PROJECT I PRE-DEVE OPMENT BASIN 4, SUB-BASIN 4-6 BASIN SUMMARY BASIN ID: P4-6-10 1 NAME: BASIN 4, SUB 4-6, PRE, 10YR II SBUH MET ODOLOGY I TOTAL ARIA 4 .20 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE li KC24HR PERV IMP PRECIPITATION i 2 . 90 inches AREA. . : 2 . 19 Acres 2. 0i Acres TIME INTERVAL j 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 °min ABSTRAC ION COEFF: 0 .20 PEAK RA E: 2 . 12 cfs VOL: 0 . 70 Ac-ft TIME: 480 min BASIN II : P4-6-100 NAME: BASIN 4, SUB 4-6, PRE, 100YR SBUH ME HODOLOGY i .TOTAL £ 'EA i 4 .20 Acres BASEFLOWS : 0 . 00 cfs RAINFAL TYPE II KC24HR PERV IMP PRECIPI ATION 3 . 90 inches AREA. . :2 . 19 Acres 2 . 01 Acres TIME IN ERVAL 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRAC ION COEFF: 0 . 20 PEAK RA E: 3 . 13 'cfs VOL: 1. 02 Ac-ft TIME: 480 min BASIN ID : P4-6-2 NAME: BASIN 4, SUB 4-6, PRE, 2YR SBUH ME HODOLOGY TOTAL £ 'EA i 4 . 20 Acres BASEFLOWS : 0 . 00 cfs RAINFAL TYPE I KC24HR PERV IMP 1 PRECIPITATION I 2 . 00 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME IN ERVAL j 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 , min ABSTRAC ION COEFF: 0 . 20 PEAK RAZE: 1 . 26 cfs VOL: 0 .43 Ac-ft TIME: 480 min BASIN ID : P4-6-25 1 NAME : BASIN 4, SUB 4-6, PRE, 25YR SBUH ME I HODOLOGY TOTAL L "EA 4 . 20 Acres BASEFLOWS : 0 . 00 cfs RAINFAL TYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 2 . 19 Acres 2 . 01 Acres I TIME INTERVAL I 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRAC I ION COEFF: 0 . 20 PEAK RA E: 2 . 62 cfs VOL: 0 . 86 Ac-ft TIME: 480 min I I II' I I 1 9/3/98 3 : 37 :54 pm.Sverdrup Civil Inc page 2 , THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEVELOPMENT BASIN 4, SUB-BASIN 4-6 BASIN SUMMARY BASIN ID: P4-6-5 NAME: BASIN 4, SUB 4-6, PRE, 5YR I SBUH METHODOLOGY TOTAL AREA 4 . 20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL 10 . 00 min CN - • 83 .44 98 .13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF;: 0 .20 PEAK RATE: 1 . 64icfs VOL: 0 . 55 Ac-ft TIME: 480 min BASIN ID: P4-6-50, NAME: BASIN 4, SUB 4-6, PRE, 50YR SBUH METHODOLOGY TOTAL AREA I: 4 . 20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 1 3 .45 inches AREA. . : 2 . 19 Acres 2 . 01 Acres , , TIME INTERVAL I: 10 . 00 min CN 83 .44 98 . 13 TC 8 .,00 min 8 . 00 min ABSTRACTION COEFFi: 0 . 20 PEAK RATE: 2 . 67: cfs VOL: 0 . 88 Ac-ft TIME: 480 min BASIN ID: P4-6-WQ NAME: BASIN 4, SUB 4-6, PRE, WQ SBUH METHODOLOGY TOTAL AREA 4 .20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL. . . . : 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 26 cfs VOL: 0 . 09 Ac-ft TIME: 480 min I I I I 1 APPENDIX C I 1 Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2220\wp\dmrpt01.doc Appendix C September 1998 APPEN IX C DEVELOPED SITE HYDROLOGY This app ndix contains information related to Section IV(B) "Developed Site Hydrology" and is organized as follows: 1. Basin A CSTC Site Basin I ' Figure C.1' - Post-Development Surface Water Management Drainage Basins. This figure indicates proposed flow travel path information and existing conditions used to complete Area Weighted Runoff Coefficient table, below. Table-Area Weighted Runoff Coefficient. The table includes soil groups, hydrologic soil groups, runoff curve numbers, proposed land use descriptions, and areas of each particular land use. This information is combined to determine the pervious and impervious area runoff curve numbers. Table - Post-Development Surface Water Management Time of Concentration or Travel Time. Detailed post-development Surface Water Management hydrographs for Water Quality, 2-, 5-, 10-, 25-, 50-, and 100-year, 24-hour events and the 100-year 7-day event. 2. Basin B I South Main Track Basin Figure C.1 - Post-Development Surface Water Management Drainage Basins. This figure indicates proposed flow travel path information and existing conditions used to complete the Area Weighted Runoff Tables, below. Table - Area Weighted Runoff Coefficients for each subbasin. The tables include soil groups, hydrologic soil groups, runoff curve numbers, proposed land use descriptions, and areas of each particular land use. This information is combined to determine the pervious and impervious area runoff curve numbers. Table - Post-Development Surface Water Management Time of Concentration or Travel Times for each subbasin. Detailed pre-development Surface Water Management hydrographs for each subbasin for Water Quality, 2-, 5-, 10-, 25-, 50-, and 100-year, 24-hour events and the 100-year 7-day event. I Surface Watr Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220 wp\drnrpt0l.doc I Appendix C-1 September 1998 UB 7A7..2....11.1 1tb B.-3 r,..t..k0VPROJECTSITE SCALE: NONE SPRINGB ••K CREEK 1,',, 1;..,, A._•__ ii-_,,,,, 1 N:=.-.- A- wmo-‘u--- w• v-: i' ee-" n, l. f.''.'--.'!'14'0ri4-0‘-L1 I1' 12111' 1•-'' 1..,,''.,,,,,* i.,)` - n11rp."4• m. v-.- 4.•• a 1tk:• i„, r=.., 47... k..-.,1L.. 4. 6'4:..14-:),- 44-:•.-.*',:. b.*i*- VNt0N 0_"__,,.__e._'-_a__•.c_"c_a5_-2.m-..i1.. 3. i1e11:rlf;.7* l.se4' 2-; BASIN 5- 4 %'- P 7ar.1. r‘.. 1.— t.:t11t'1T.711. 1111-111. i10r167t`,v1*_.; 1'11: 7i ,. , 4Iiillm_.! , i ii a,... - a --"-•-- -- -- ----'- Ih"---...111"41- 16ZA.---- 11,,t:, i."1-itEril.1 \,,-...-,.,, 2. . ,. . 774I 1 1,= * ' ' .--•-•-•- '''' A ...All*L VII t ' '--. '"lik, i "1"1". 16: 1' ( ' _2 :IT s 1%2* '•,,..:::4z.... .----- , 047r/-,,,i- 1 6 1 . 1, t•i v ', 1fill 1....10 i.17 l'1 1 s........L,„.m., ,1 4 A i. f 1 ii I 111........-..=......-••. 1, 411141$100I 1, Al1471t9". -7j--- 14t tlitt. '4 .••7---\...,sw 16th ST 1 2_ -• -!ii 0 \Ilk ,,,T,,,....i., ,..,,,,, , .... ---_,:•----___ -----1,1 .,, _ _ tifi ,, Jo i ';41: " l' ii r i 41,s DI\adffr --_____ ..,,, ...i.7,77---.....:....--_,...-....,1,0:-,-,..--:.4.,,,,,,1„0:,- r,... .:.._,....,... •_,..11 __. / 1 r-1, obi: ,,,'..,';',4; :41' Iiiii - I; T 11:--. 111111111111111g: I i.al , _....iiima......_.....--,_-,-- --5...................."'"-- 7- -......-,..:•07.0' \."2„..,sihi.,___I 1,4 jj ;1 1, 1iv,.4.0„;,,,,, -.,•;.....sap,- f r...."--.-.-....-4,•------ I -- if 14 -r" IT 41 4, Tail NLARGEMINT OF CSTC - imi'rniiii__ jika".$1SITESOILGROUPSviiTLANDANDDETENTION'1/4. . .mm0. ,„_,,..„ 1 ff 1.COMBINED WE TPOND/ j ''DETENTION POND i 4.-_,..m.,........ki• 1„..,,,,..-rid1111...' ----.0a, c.',,,,------iin ' -......-r---- .---- 4...... - gtial —r- 2'.-UR - URBAN LAND ir''.t.--+-1-'17,7: •,,..,•,, P_ C‘_ ..‘ Iv 11"."111'....".-1 1 .71 WO - WOODINVILLE SILT LOAM \ I- A PY - PUYALLUP FINE SANDY LOA` '1 : -:----- 1 V' II --ipNG - NEWBERG SILT LOAM 71',• .T.-- , , 0 glormi0*W r.,, - i -- UPRR e II 1 i s \\ ...._._ kVD i f 111111r--"-"-*/1 ilM•VI;A U R go 1IIJulke.,,'-"' .2•01,..„IA 1r aci , linagrill Dc3i ii, ..... Joy— 74IPiiiliII , '01-11 g . 11 am En t _-,1-'"----,, „...ad 6,.. L.+. 00 MB lit MIM:I4 4"'.:;,'•,4 M'.::...•!,E,, 4 1l117 MUM NSea i-rt-5r.. i- c-1n1t95f1 Y141G Ag '' N GREEN RIVER Aculurr iMSCIINIvNI/m1e1-er.mdINrCmuo.m sitravaL walim .1m1P05T-CIEVELOPIABIT DRAINAGE BASINSgaire3Z• MtlagEPP=AMISS REPORT FIG. C.1ei_AmerirAvar• IMMO VI INIPL re sass Nan SURFACE WATER MANAGEMENT ROM PROJECT mai. 014002 IllIsinums 1imoOSIERROMLoamof=PA I I 1 I. The Boeing Company II Surface Water Management Project(SWMP) 11 Area Weighted Runoff Coefficient Post-Development SWMP l 1 1 Drainage Basin A South Main Track Basin) Sub-Basin A-1 Soil II Hydrologic Curve Land Use Area Weight Weighted Group I Hydro Group Number 1 Description Curve Nst) umber Ur I C I 187 (Sand Racing Track(dirt road) 200,038 7%I 5.70 Ur I D 198 I Building Roofs 203,789 7% 6.54 Ur I D 98 I Pavements 494,685 j 16%15.87 Ur II D T 92 Horse Walking Areas(fair) 1 305,321 j 10%9.20 Ur 1 I D 91 Gravel Parking Lots I 313,371 1 10%9.34 Ur D 90 Lawns 1,050,258 j 34%30.95 Ur D 90 Landscaping(good) 98,495 3% 2.90 Ur I D 89. Meadow 84,226 3% 2.45 Wo I D 98 •Pavements 9,549 0% 0.31 Wo 1 D 92 Lawns 143,065 5% 4.31 I Wo I D Ng 9,1 Gravel Parking Lots 35,991 1%1 1.07II B 98 Pavements 17,052 1% 0.55, 1 Ng j I B I 85 'Gravel Parking Lots 9,447 I 0%1 0.26', Ng I I B I 85 I Lawns(fair) I 88,534 I 3%1 2.461 TOTALS 1 1 i 1 1 3,053,821 1 100% i 86.22 I Notes: I1. Soil groups estimated from Sail Survey of King CountyArea, Washington, Des Moines Quadrangle 1973 2. Hydrologic\groups determined from King County Surface Water Design Manual, Figure 3.5.2A 1 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B 11 Impervious area(!curve number>=98) 16.65 Acres 1 Impervious area curve number 98.00 i Peril ious area(curve number<98) 53.46 Acres Pervious area curve number 90.03 1 Basin Composite Curve Number 86.22 Basin Total Area 70.11 Acres f I 1 1 I 1, I I 01389 /2220/engr/-Kbcalcl6.xls[Post-Basin A-1] 9/10/98 Sverdrup Civil,Inc. I I I 1 I The Boeing Company Surface Water Management Project (SWMP) Post-Development SWMP Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-1 Sheet Flow(Applicable to Te only) Surface description (see Table 3.5.2C) Manning's roughness coefficient, nsheet 015° . .` "`; `;: . = Flow length (L<=300'), Ltheet 50<feet- H;.; 2-year, 24-houri rainfall, P2 2.00inches Land slope, Ssheet 0.040 ft/ft-='; Ttsheet 0.09 hours Ttsheet 5.4 min Channel Flow, Section 1 Surface description (see Table 3.5.2C) concrete.pipe Flow length, II 1900 ftchannel Watercourse slope, Schannel 0 005 ft/ft ;;" ' . :. ' Factor, ke (see Table 3.5.2C)42 . Velocity,Vchannei 3.0 f/S Ttchannel 0.18 hours Tt channel 10.7 min • Results:Basin A (Post-Development) Total Tc or Tt 0.27 hours Total Tc or Tt 16.1 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalc17.xls[Post-Basin A-1]9/9/98 Sverdrup Civil,Inc. I 9/10/ I810 :7 :48 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN A, SUB-BASIN A-1 BASIN SUMMARY BASIN ID: DA-1-10 NAME: BASIN A, SUB A-1, POST, 1OYR SBUH METHODOLOGY\ TOTAL (AREA 70 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IiMP PRECIPITATION 2 . 90 inches AREA. . : 53 .46 Acres 16 . 65 Acres TIME ITERVAL 10 . 00 min CN 90 . 03 98 . 00 TC 16 . 10 min 16 . 10 min ABSTRACTION COEFF: 0 .20 PEAK RTE: 33 .40', cfs VOL: 12 . 15 Ac-ft TIME: 480 min BASIN ]D: DA-1-100 NAME: BASIN A, SUB A-1, POST, 100YR SBUH METHODOLOGYliTOTALAREA 70 . 11 Acres BASEFLOWS: 0 . 00 cfs RAINFALIL TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 53 .46 Acres 16 . 65 Acres TIME INTERVAL 10 . 00 min CN 90 . 03 98 . 00 TC 16 . 10 min 16 . 10 min ABSTRACTION COEFF 0 .20 PEAK RATE: 49 . 21 \\cfs VOL: 17 . 68 Ac-ft TIME: 480 min BASIN I : DA-1-2 I NAME : BASIN A, SUB A-1, POST, 2YR SBUH METHODOLOGY TOTAL AREA 1 70 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 53 .46 Acres 16 . 65 Acres TIME INTERVAL I 10 . 00 min CN 90 . 03 98 . 00 TC 16 . 10 min 16 . 10 min ABSTRACTON COEFF: ', 0 . 20 PEAK RATE: 19 . 57 cfs VOL: 7 .34 Ac-ft TIME : 480 min BASIN ID: DA-i-25 NAME : BASIN A, SUB A-1, POST, 25YR SBUH METI'pDOLOGY TOTAL AREA 70 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL \TYPE li KC24HR PERV IMP PRECIPITATION I 3 .40 inches AREA. . : 53 .46 Acres 16 . 65 Acres TIME INTERVAL 10 . 00 min CN 90 . 03 98 . 00 TC 16 . 10 min 16 . 10 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 41 . 27 cfs VOL: 14 . 90 Ac-ft TIME : 480 min I 1 9/10/98. 10 :7 :48 am Sverdrup Civil Inc page 2 THE BOEING COMPANY i ' SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN A, SUB-BASIN A-1 BASIN SUMMARY BASIN ID: DA-1-5 NAME: BASIN A, SUB A-1, POST, 5YR SBUH METHODOLOGY TOTAL AREA 70 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 53 .46 Acres 16 . 65 Acres TIME INTERVAL 10 . 00 min CN 90 . 03 98 . 00 TC 16 . 10 min 16 . 10 min ABSTRACTION COEFF: . 0 .20 PEAK RATE: 25 . 63 cfs VOL: 9 .45 Ac-ft TIME: 480 min BASIN ID: DA-1-50 NAME: BASIN A, SUB A-1, POST, 50YR SBUH METHODOLOGY ' TOTAL AREA 70 . 11 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 53 .46 Acres 16 . 65 Acres ' _' TIME INTERVAL 10 . 00 min CN 90 . 03 98 . 00 TC 16 . 10 min 16 . 10 min ABSTRACTION COEFF: 0 . 20 PEAK RATE : 42 . 07 'cfs VOL: 15 . 17 Ac-ft TIME: 480 min U. BASIN ID: DA-1-WQ' NAME: BASIN A, SUB A-1, POST, WQ SBUH METHODOLOGY ' TOTAL AREA 70 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . .: KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 53 .46 Acres 16 . 65 Acres TIME INTERVAL. . . .;: 10 . 00 min CN 90 . 03 98 . 00 TC 16 . 10 min 16 . 10 min , ABSTRACTION COEFF: 0 . 20 PEAK RATE: 2 . 32 cfs VOL: 1 . 24 Ac-ft TIME: 480 min 1 I I I The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Post-Development SWMP I Drainage Basin A CSTC Basin) Sub-Basin A-2 Soil Hydrologic Curve Land Use Area Weight Weighted Group ,I Group Number Description sf) I Curve Number Ur i D I 98 1 Building Roofs 1 278,260 10% 1 9.61 Ur D 98 Pavements 788,620 28%27.25 Ur D 90 Landscaping(good) 1,548,103 I 55%49.12 Ur D I 100 1Water Surfaces 212,421 7% 7.49 Py I B 98 1 Pavements 8,978 0% 0.31 TOTALS I 2,836,382 I 100% 93.78 I Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 i 2. Hydrologic groups determined from King County Surface Water Design Manual, Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>=98) 29.57 Acres Impervious area curve number 98.33 Pervious area(curve number< 98) 35.54 Acres Pervious area curve number 90.00 1 Basin Composite Curve Number 93.78 Basin Total Area ! 65.11 Acres I, I I I I I 013893 2220/engr/-Kbcalc16. i s[Post-Basin A-2] , 9/9/98 Sverdrup Civil,Inc. 1 The Boeing Company Surface Water Management Project (SWMP) Post-Development SWMP Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-2 Sheet Flow(Applicable to T, only) Surface description (see Table 3.5.2C) asphalt-parking lot Manning's roughness coefficient, nsheet 0:01;1 Flow length (L<=300'), 4neet 70 feet.; 2-year,24-hour rainfall, P2 2.00 inches Land slope, Ssheet 0:020Yftfft ;; Ttsheet I 0.02 hours Ttsheet 1.2 min Channel Flow, Section 1 Surface description (see Table 3.5.2C) concrete pipe Flow length, channel 1220 ft' Watercourse slope, Schannel 0.005-0 Factor, ks (see Table 3.5.2C)42 , Velocity, Vchannel 3.0 f/s Tt channel 0.11 hours Ttchannel 16.8 min Results:Basin A (Post-Development) Total Ts or Tt 10.13 hours Total Tc or Tt j 8.0 min Notes: F 1. Worksheet is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalcl7.xls[Post-Basin A-2]9/9/98 Sverdrup Civil,Inc. 9/9/98 11 : 3 :3 am Sverdrup Civil Inc page 1 li I I THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN A, SUB-BASIN A-2 I BASIN SUMMARY BASIN ID: DA-2-10 NAME: BASIN A, SUB A-2, POST, 10YR SBUH ETHODOLOGY I TOTAL !AREA L : 65 . 11 Acres KC24HR BASEFLOWS : 0 . 00 cfs RAINFAhL TYPE PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 35 . 54 Acres 29 . 57 Acres TIME INTERVAL h 10 . 00 min CN 90 . 00 98 .33 I TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 38 . 1i cfs VOL: 12 . 27 Ac-ft TIME: 480 min I BASIN ID: DA-2-1010 NAME : BASIN A, SUB A-2, POST, 100YR SBUH METHODOLOGY1 TOTAL AREA 65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE i• TIME INIERVAL. . . . I KC24HR PERV IMP PRECIPITATION i• 3 . 90 inches AREA. . : 35 . 54 Acres 29 . 57 Acres 10 . 00 min CN 90 . 00 98 .33 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF 0 . 20 PEAK RATE: 54 .47kkcfs VOL: 17 .49 Ac-ft TIME: 480 min BASIN ID: DA-2-2 SBUH METHODOLOGY j NAME: BASIN A, SUB A-2, POST, 2YR ITOTAL AREA I1 65 . 11 Acres BASEFLOWS: 0 . 00 cfs RAINFALII, TYPE KC24HR PERV IMP PRECIPITATIONTIME I7ERVAL2 . 00 inches AREA. . : 35 . 54 Acres 29 . 57 Acres I 10 . 00 min CN 90 . 00 98 . 33 TC 8 . 00 min 8 . 00 min ABSTRAC !ION COEFF: ; 0 .20 PEAK RAT : 23 . 64 cfs VOL: 7 . 70 Ac-ft TIME: 480 min I BASIN ID: DA-2-25 I NAME : BASIN A, SUB A-2 , POST, 25YR SBUH MET ODOLOGY TOTAL AREA 65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE I KC24HR PERV IMP PRECIPITATION I 3 .40 inches AREA. . : 35 . 54 Acres 29 . 57 Acres TIME INTERVAL I 10 . 00 min CN 90 . 00 98 .33 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: I 0 . 20 PEAK RATE : 46 . 28 cfs VOL: 14 . 87 Ac-ft TIME : 480 min 11 I . I 1 I I 9/9/9.8 11 :3 :32 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN A, SUB-BASIN A-2 BASIN SUMMARY BASIN ID: DA-2-5 NAME: BASIN A, SUB A-2 , POST, 5YR SBUH METHODOLOGY TOTAL AREA 65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 35 . 54 Acres 29 . 57 Acres TIME INTERVAL 10 . 00 min CN-90 . 00 98 . 33 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: , 0 . 20 PEAK RATE: 30 . 02 cfs VOL: 9 . 71 Ac-ft TIME: 480 min BASIN ID: DA-2-50 ; NAME: BASIN A, SUB A-2, POST, 50YR SBUH METHODOLOGY , 1 TOTAL AREA 65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 35 . 54 Acres 29 . 57 Acres ; , TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 33 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFFi 0 . 20 PEAK RATE: 47 . 09: cfs VOL: 15 . 13 Ac-ft TIME: 480 min BASIN ID: DA-2-WQ NAME: BASIN A, SUB A-2, POST, WQ SBUH METHODOLOGY TOTAL AREA 65 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 35 . 54 Acres 29 . 57 Acres ' 1 TIME INTERVAL 10 . 00 min CN 90 . 00 98 . 33 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 4 .38 cfs VOL: 1 . 62 Ac-ft TIME: 480 min 1 1 I The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Post-Development SWMP I Drainage Basin A Delta Area Basin) Sub-Basin A-3 Soil Hydrologic Curve Land Use Area Weight Weighted Group Group Number I Description Of) Curve Number Ur 1 D 190 'Landscaping(good) 121,924 32% I 26.83 Ur 1 D , 1100 'Water Surfaces 42,836 11%1125 Py I B I 198 Pavements 5,248 1% 1.35 Py B 1 80 ,Landscaping(good)189,678 50% I 39 i86 Py B 100 Water Surfaces 20,956 6%1 5.51 TOTALS I I I I 1 380,642 100% 1 86.80 Notes: I 1. Soil gro ps estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrolo is groups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve N ktubers determined Ifro,m King County Surface Water Design Manual,Table 3.5.2B II pervious area(curve number>=98) 1.58 Acres Impervious area curve number 99.85 Pervious area(curve number<98) 7.15 Acres P rvious area curve number 83.91 Basin Composite Curve Number 86.80 Basin Total Area 8.74 Acres i_ I I 0138.3/2220/engr/-Kbcalc16.xls[Post-Basin A-3] 9/9/98 Sverdrup Civil,Inc. I I l I The Boeing Company Surface Water Management Project (SWMP) Post-Development SWMP Time of Concentration or Travel Time Drainage Basin A CSTC Site Basin) Sub-Basin A-3 Sheet Flow(Applicable to T, only) Surface description'(see Table 3.5.2C) lawn ' -.= Manning's roughness coefficient, nsheet Flow length (L<=300'), I-sheet 200 feet:: 2-year, 24-hour rainfall, P2 2.00 inches.~ : .'' Land slope, Ssheet ; 0:020 ft/ft_', Ttsheet 0.36 hours Ttsheet 21.6 min Shallow Concentrated Flow Surface description (see Table 3.5.2C) brushy ground;rivith:some;tree5".';:;, Flow length, Lshallow 125ft; Watercourse slope, Sshallow 0.060 ft/ft Factor, ks (see Table 3.5.2C) 5. Velocity, Vshallow 1.2 f/s Ttshallow 0.03 hours Ttshallow 1.7 min Results:Basin A (Post-Development) Total To or Tt 0.39 hours Total Ts or Tt ; j 23.3 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds, 2nd Edition (Technical Release Number 55), US SCS, 1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual 013893/2220/engr-Kbcalc17.xls[Post-Basin A-3]9/9/98 Sverdrup Civil,Inc. I 9/9/98 11 :3 :48 am Sverdrup Civil Inc page 1 I THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-6EVELOPMENTBASIN A, SUB-BASIN A-3 I BASIN SUMMARY II I BASIN ID: DA-3-10 NAME: BASIN A, SUB A-3 , POST, 10YR SBUH METHODOLOGY k, TOTAL AREA 8 . 73 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE I • KC24HR PERV IMP PRECIPITATION ! • 2 . 90 inches AREA. . : 7 . 15 Acres 1 .158 Acres TIME INTERVAL. . . . : 10 . 00 min CN 83 . 91 99 . 85 TC 23 . 30 min 23 . 30 min ABSTRACTION COEFF: 0 . 20 PEAK RATE : 2 . 75! cfs VOL: 1 .23 Ac-ft TIME: 480 min BASIN IID: DA-3-100 NAME: BASIN A, SUB A-3 , POST, 100YR SBUH METHODOLOGY TOTAL AREA 8 . 73 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 7 . 15 Acres 1 . 58 Acres TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 .30 min 23 . 30 min ABSTRACITION COEFF 0 . 200 . 20 PEAK RATE: 4 . 38 ;cfs VOL: 1 . 87 Ac-ft TIME: 480 min BASIN ID: DA-3-2 NAME : BASIN A, SUB A-3 , POST, 2YR SBUH METHODOLOGY TOTAL AREA 8 . 73 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 7 . 15 Acres 1 . 58 Acres TIME INTERVAL I 10 . 00 min CN 83 . 91 99 . 85 TC 23 .30 min 23 . 30 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 1 .42 cfs VOL: 0 . 70 Ac-ft TIME: 480 min II I. BASIN IDI. DA-3-25 ! NAME: BASIN A, SUB A-3 , POST, 25YR SBUH METHODOLOGYIITOTALAREA 8 . 73 Acres BASEFLOWS : 0 . 00 cfs RAINFALL \TYPE I KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 7 . 15 Acres 1 . 58 Acres TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 . 30 min 23 .30 min ABSTRACTION COEFF: 10 . 20 PEAK RATE: 3 . 55 cfs VOL: 1 . 54 Ac-ft TIME: 480 min I 9/9/98 11 :3 :48 am./ Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN A, SUB-BASIN A-3 BASIN SUMMARY BASIN ID: DA-3-5 NAME: BASIN A, SUB A-3 , POST, 5YR SBUH METHODOLOGY TOTAL AREA 8 . 73 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE j KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 7 . 15 Acres 1 . 58 Acres , ! TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 . 30 min 23 . 30 min ABSTRACTION COEFF: 1 0 . 20 PEAK RATE: 1 . 99 cfs VOL: 0 . 93 Ac-ft TIME: 480 min BASIN ID: DA-3-50 , NAME: BASIN A, SUB A-3 , POST, 50YR SBUH METHODOLOGY TOTAL AREA 8 . 73 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 7 . 15 Acres 1 . 58 Acres TIME INTERVAL 10 . 00 min CN 83 . 91 99 . 85 TC 23 .30 min 23 . 30 min ABSTRACTION COEFF? 0 . 20 PEAK RATE: 3 . 63 , cfs VOL: 1 . 58 Ac-ft TIME : 480 min BASIN ID: DA-3-WQ; NAME: BASIN A, SUB A-3 , POST, WQ SBUH METHODOLOGY TOTAL AREA 8 . 73 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 7 . 15 Acres 1 . 58 Acres TIME INTERVAL. . . .i : 10 . 00 min CN 83 . 91 99 . 85 TC 23 . 30 min 23 . 30 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 .21 cfs VOL: 0 . 11 Ac-ft TIME: 480 min I The Boeing Company Surface Water Management Project (SWMP) Area Weighted Runoff Coefficient Post-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin B-1 Soil Hydrologic Curve Land Use Area Weight Weighted Group I Group Number Description sfl Curve Number Ur j D I98 Building Roofs 4,000 1% 1.08 1.35UrIDI ,98, !Pavements 5,000 1% Ur D 91 Gravel Parking Lots 27,275 8% 6.86 Ur 87 ;Sand Racing Track(dirt road) 39,648 11%9.53 Ur j I C D 90 Lawns 208,686 58%51.91 Ur ! D 92 Horse Walking Areas(fair) 60,517 17%15.39 Ur ! D 89 (Meadow 16,694 5% 4.11 TOTALS I I I I 361,820 I 100% 90.23 1 i Notes: I 1. Soil groups estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2E Impervious area(curve number>=98) 0.21 Acres Impervious area curve number 98.00 Pervious area(curve number< 98) 8.10 Acres Pervious area curve number 90.04 I Basin CompositelCurve Number 90.23 Basin Total Area II 8.31 Acres I I I j I I I II-I I I I 01389 2220/engr/-Kbcalcl6.xls[Post-Basin B-1] 9/10/98 Sverdrup Civil,Inc. I I The Boeing Company Surface Water Management Project(SWMP) Post-Development SWMP Time of Concentration or Travel Time Drainage Basin B South Main Track Basin) Sub-Basin B-1 I Sheet Flow(Applicable to T,only) Surface description(see Table 3.5.2C) Short grass grade-' - " • Manning's roughness coefficient,ne,,a Row length(L<=300'), 2-year,24-hour rainfall,P2 2.00 Inches,'"-' Land slope,S„„„ 0.003 ft/It 0.59 hours 135 min I Shallow'Concentrated Flow Surface description(see Table 3.5.2C) Brushy ground withSome trees(lit=0.060). Row length,La„a,,, t00ft;':•`:;' ,,, Watercourse slope, Factor,k,(see Table 3.5.2C) 5, Velocity:V„„„ 02 Us T,„„ao„ 0.14 hours T,emir; 9 min Channel Flow,Section 1 Surface description(see Table 3.5.2C) Earth lined waterway(neo.0251• Flow length,La.„w Watercourse slope,Sow, 0.017 f/It, Factor,k„(see Table 3.5.2C) Velocity,Vd„,,,,,, 12.6 f/s T,„,a„„l 0.11 hours 7min Channel Flow,Section 2 Surface description(see Table 3.5.2C) Concrete pipe(n=0012) Row,length,Ld„„„, 127.0ft Watercourse slope,S„„,,,„, 0.006ift/ft. Factor,k,(see Table 3.5.2C) 42 Velocity,Vd„„,„ 13.3 f/s T,channel 10.01 hours 10.65 min Channel Flow,Section 3 Surface description(see Table 3.5.2C) !Grassed waterway(1t_0.025) Row length,Ldw„„, 540:0 ft Watercourse slope,Sc,„„„„, 0.005 ttflt - Factor,k,(see Table 3.5.2C) Velocity,V„„„,„ 11.1 f/s T„r„„,„ 10.13 hours T,„„„n„ 17.89 min Channel Flow,Section 4 Surface description(see Table 3.5.2C) CMP pipe"(n=0.024)'= Flow length,Ld„„„ Watercourse slope,S„„„,„ 0.003 ftlft Factor,k,(see Table 3.5.2C) Velocity,Vd„„,„ 1.1 f/s Trchannel 0.01 hours Trdunned 0.90 min Results:Basin B Sub-Basin B2(Post-Development) Total T,or T,11.00 hours Total T,orT,160 min Notes: 1.Worksheet isbased on UrbanHydrologyfor Small Watersheds,2nd Edition(Technical Release Number 55),US SCS,1986 2. Worksheet modified to conform with Section 3.5.2 of the Ming County Surface WaterDesign Manual 013993/2220/engr•Kbcalc17.els(Post-Basin B-1) 9/8/98 SverdrupOW,Inc. I 9/10/98 10 : 9 : 1!1 am Sverdrup-Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT I POST-DIEVELOPMENTiBASIN B, SUB-BASIN B-1 BASIN SUMMARY BASIN ID: DB-1-10 NAME: BASIN B, SUB B-1, POST, 10YR SBUH METHODOLOGY ; TOTAL AREA i . 8 .31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . :, :'KC24HR PERV I'4P PRECIPITATION 2 . 90 inches AREA.. : 8 . 1004 Acres 0 .21 Acres TIME INTERVAL. . . .'I : 10 . 00 min CN 90 . 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFFI: 0 .20 PEAK RATE: 2 . 15 cfs VOL: 1 .33 Ac-ft TIME: 490 min I BASIN ID: DB-1-100 NAME : BASIN B, SUB B-1, POST, 100YR SBUH METHODOLOGY TOTAL AREA 8 .31 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION i 3 . 90 inches AREA. . : 8 . 10 Acres 0 . 21 Acres TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 I i TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF:I 0 . 20 PEAK RA' E: 3 . 301.cfs VOL: 1. 97 Ac-ft TIME: 490 min I BASIN ID: DB-1-2 INAME: BASIN B, SUB B-1, POST, 2YR SBUH METHODOLOGY TOTAL AIEA II1 8 . 31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE PRECIPITATION I PERV IMP 2 . 00 inches AREA. . : 8 . 10 Acres 0 . 21 Acres TIME INTERVAL I 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min 1 ABSTRACTION COEFF: 'I 0 . 20 PEAK RATE: 1 . 16 cfs VOL: 0 . 77 Ac-ft TIME : 490 min II BASIN ID: DB-1-25 II NAME: BASIN B, SUB B-1, POST, 25YR II SBUH METHODOLOGY i TOTAL AREA 8 . 31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL \TYPE I KC24HR PERV IMP li PRECIPITATION i 3 .40 inches AREA. . : 8 . 10 Acres 0 . 21 Acres II TIME INTERVAL l 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 2 . 72 cfs VOL: 1 . 65 Ac-ft TIME: 490 min I Y ' I I I, I I I I i I 9/10/98 10 : 9 :11 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN B, SUB-BASIN B-1 BASIN SUMMARY BASIN ID: DB-1-5 NAME: BASIN B, SUB B-1, POST, 5YR SBUH METHODOLOGY TOTAL AREA 8 . 31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 8 . 10 Acres 0 .21 Acres TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 1 . 59 cfs VOL: 1 . 01 Ac-ft TIME: 490 min BASIN ID: DB-1-50 . NAME: BASIN B, SUB B-1, POST, 50YR SBUH METHODOLOGY TOTAL AREA 8 .31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 8 . 10 Acres 0 . 21 Acres TIME INTERVAL J 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF 0 . 20 PEAK RATE: 2 . 78 !cfs VOL: 1 . 68 Ac-ft TIME: 490 min BASIN ID: DB-1-WQr NAME: BASIN B, SUB B-1, POST, WQ SBUH METHODOLOGY TOTAL AREA 8 .31 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP I PRECIPITATION 0 . 67 inches AREA. . : 8 . 10 Acres 0 .21 Acres ! ' TIME INTERVAL 10 . 00 min CN 90 . 04 98 . 00 TC 60 . 00 min 60 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 08 cfs VOL: 0 . 10 Ac-ft TIME: 760 min I I- I 1 The Boeing Company I Surface Water Management Project(SWMP) I Area Weighted Runoff Coefficient Post-Development SWMP 1I I 1 Drainage Basin B South Main Track Basin) I Sub-Basin B-2 Soil Hydrologic I Curve Land Use Area Weight Weighted Group I Group Number Description sf) Curve Number Ur H D Ur 98 Building Roofs 11,011 3% 2.98 D 98 Pavements 14,109 ;4% 3.82 Ur j Ur ; D 91 Gravel Parking Lots 60,755 j 17%15.26 C 87 Sand Racing Track(dirt road) 25,700 j 7% 6.1p Ur D 90, Lawns 170,000 47%42.23 Ur D 92 Horse Walking Areas(fair) 53,860 15%13.68 Ur D 89 Meadow 26,859 I 7% 6.6b TOTALS 1 I , 1 1 362,294 I 100% I 90.73 I Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 I2. Hydrologic groups determined from King County Surface Water Design Manual, Figure 3.5.2A I 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>= 98) 0.58 Acres Impervious area curve number 98.00 Pervious area(curve number<98) 7.74 Acres I Pervious area curve number 90.19 Bain Composite\Curve Number 90.73 I Basin Total Area I; 8.32 Acres I I I I I I 1 I 1 I 1 0 I 13893(2220/engr/-Kbcalcl6.\Is[Post-Basin B-2] 9/9/98 Sverdrup Civil,Inc. I The Boeing Company Surface Water Management Project(SWMP) Post-Development SWMP Time of Concentration or Travel Time Drainage Basin B South Main Track Basin) Sub-Basin B-2 Sheet Flow(Applicable to Ta only) Surface description(see Table 3.5.2C) Bars soil• Manning's roughness coefficient,r ge„ 0.011, ; Flow length(L<=300'),L 80 feet;.-:_. 2-year,24-hour rainfall,P2 200 inches;.' Land slope, 10.02 hours 11 min Shallow Concentrated Flow Surface description(see Table 3.5.2C) Flow length, . rO ft. Watercourse slope,Se,,,a„ 44000.000 ft/ft Factor,k,(see Table 3.5.2C) 11 Velocity,Va„d,,, 2307.4 Us T,e,,,,,e, 0.00 hours j T,a eaa 0 min Channel Flow,Section 1 Surface description(see Table 3.5.2C) Grassedwaterway(n=0.025) Flow length,Ld.ma 830 ft - rrrr, Watercourse slope,Sdun 0.005tVft . . Factor,k,(see Table 3.5.2C) 17 Velocity,Vdv,v,,, 11.2 f/s Menne 10.19 hours Ti channel 112 min Channel Flow,Section 2 Surface description(see Table 3.5.2C) 4CMP pipe(n 0.024) r Flow length,Ld,,a 117.0ft Watercourse slope,Sc„.,,, Factor,ke(see Table 3.5.2C) Velocity,Vd,,,a,,, 12.5 f/s T,Ma,.,.! 10.00 hours dannel 10.11 min Channel Flow,Section 3 Surface description(see Table 3.5.2C) (Grassed waterway-(rt=0.025) I Flow length, Watercourse slope,Sd,,,,ei Factor,ka(see Table 3.5.2C) 17 ... , • Velocity;vd,,,,,,,i 1.1 f/s T,channel 0.14 hours T,d,„,aai 18.26 min Channel Flow,Section 4 Surface description(see Table 3.5.2C) ICMP pipe(n=0.024) Flow length,h„naei I60.0 ft • ' ' Watercourse slope,Sd,a,a,e, 0.003 ft/ft, • • , Factor,k,(see Table 3.5.2C) 21 Velocity,Vd,,,a,N 11.1 Us T,d,a,eI r0.01 hours T,d,anel 10.90 min Results:BasinB Sub-BasinB3(Post-Development) Total T,or T,10.36 hours Total T,or T,122 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds,2nd Edition(Technical Release Number 55),US SCS,1986 2. Worksheet modified to conform with Section 3.5.2 of the!Ong County Surface Water Design Manual 013893/2220/engr-Kbcak17.,dslPost•Basin 9.21 e/W913 Svordrup Civil,Inc. 9/9/98 11 :4 :27 am Sverdrup Civil Inc age 1 I THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN B, SUB-BASIN B-2 BASIN SUMMARY BASIN ID: DB-2-10 NAME: BASIN B, SUB B-2, POST, 10YR SBUH METHODOLOGY, TOTAL AREA. . . . . . \. : 8 .32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE l • KC24HR PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL ' • 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RFLTE: 3 . 39 cfs VOL: 1 .36 Ac-ft TIME: 480 min I BASIN ID: DB-2-160 NAME: BASIN B, SUB B-2, POST, 100YR SBUH METHODOLOGY ; TOTAL AREA 1. 8 . 32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE 1• KC24HR PERV IMP PRECIPITATION I. 3 . 90 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF 0 . 20 PEAK RATE: 5 . 11cfs VOL: 2 . 01 Ac-ft TIME: 480 min BASIN ID: DB-2-2 \ NAME: BASIN B, SUB B-2, POST, 2YR SBUH METHODOLOGY TOTAL AREA I 8 . 32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE I KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL I ' 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF:'I 0 .20 PEAK RATS : 1 . 90 cfs VOL: 0 . 80 Ac-ft TIME : 480 min II BASIN ID: DB-2-25 ', NAME: BASIN B, SUB B-2 , POST, 25YR SBUH METHODOLOGY TOTAL AREA RAINFALLITYPE 8 . 32 Acres BASEFLOWS : 0 . 00_ cfs Ii KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL II 10 . 00 min CN 90 . 19 98 . 00 1,-- 1-:-, TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 4 . 25 cfs VOL: 1 . 68 Ac-ft TIME: 480 min I 9/9/9.8 11 :4 :27 am , Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN B, SUB-BASIN B-2 BASIN SUMMARY BASIN ID: DB-2-5 NAME: BASIN B, SUB B-2, POST, 5YR SBUH METHODOLOGY TOTAL AREA 8 . 32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 7 . 74 Acres 0 . 58 Acres TIME INTERVAL 10 . 00 min CN-90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min r-I ABSTRACTION COEFF: 0 .20 PEAK RATE: 2 . 55 cfs VOL: 1. 04 Ac-ft TIME: 480 min BASIN ID: DB-2-50 NAME: BASIN B, SUB B-2, POST, 50YR I SBUH METHODOLOGY TOTAL AREA 8 . 32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 7 . 74 Acres 0 . 58 Acres : TIME INTERVAL 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF 0 . 20 PEAK RATE : 4 . 33 : cfs VOL: 1 . 72 Ac-ft TIME: 480 min BASIN ID: DB-2-WQ NAME: BASIN B, SUB B-2 , POST, WQ I , SBUH METHODOLOGY ' TOTAL AREA 8 .32 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 0 . 67 inches AREA. . : 7 . 74 Acres 0 . 58 Acres ; TIME INTERVAL 10 . 00 min CN 90 . 19 98 . 00 TC 22 . 00 min 22 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 13 cfs VOL: 0 . 11 Ac-ft TIME: 490 min The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Post-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin B-3 Soil Hydrologic Curve Land Use Area Weight Weighted Group Group Number Description sf) Curve Number Py B I '98 'Buildin Roofs 22,000 12%11178 Py _ B I 98 I Pavements 59,633 33%31194 Py B j 90 Lawns rI 35,369 19%17140 Py , B 80 Landscaping(good)r 47,464 26%20.75 Py B 100 Water Surfaces 5,860 3% 3.20 Py B I 78 Meadow 12,662 7% 5.40 TOTALS I I I I I 182,988 I 100% 90!46 Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington, Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual,Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>=98) 2.01 Acres Impervious area curve number 98.13 Pervious area(cL1rve number<98) 2.19 Acres Pervious area curve number 83.44 i ' Basin Composites Curve Number 90.46 Basin Total Area 4.20 Acres 013893/2220/engr/-Kbcalcl6.xls[Post-Basin B-3] 9/9/98 Sverdrup Civil,Inc. i I The Boeing Company Surface Water Management Project(SWMP) Post-Development SWMP Time of Concentration or Travel Time Drainage Basin B South Main Track Basin) Sub-Basin B-3 Sheet Flow(Applicable to Tc only) Surface description(see Table 3.5.2C)Short grass pride': Manning's roughness coefficient,nsheet OJ5 Flow length(L<=300'),Lsheet 25feet.:.: 2-year,24-hour rainfall,P2 2.00 inches. • Land slope,Ssheet 0A30 ft/ft Tt sheet 1 10.06 hours Tt sheet I 3 min Shallow Concentrated Flow Surface description(see Table 3.5.2C) Flow length,4halow 0 ft Watercourse slope,Sstanow 44000.000ftfft':•,:_" Factor,ksl(see Table 3.5.2C) 11; Velocity,Vshafbw 12307.4 f/s Ttshattow 0.00 hours Ttshataw 10 min Channel'Flow,Section 1 Surface description(see Table 3.5.2C)Concrete.pipe' Flow length,l-channel 575 ft, Watercourse slope,Schannei 0.0954t/ft Factor, (see Table 3.5.2C) 42 Velocity,Vchannel 13.0 f/s Tt channel I 10.05 hours Tt channel 13 min I Channel,Flow,Section 2 Surface description(see Table 3_5.2C)JCMPpipe(n=0.024)- Flow length,'-channel 155A ft.: Watercourse slope,Schannel 0.002 ft/ft Factor,kt(see Table 3.5.2C) Velocity,.Vchannel 0.9 f/s Ttchannel 1 0.02 hours Tt channel 0.98 min Results:Basin B Sub-Basin B3(Post-Development) Total Te or Tt 0.13 hours Total Tc or Tt 18 min Notes: 1. Worksheet is based on Urban Hydrology for Small Watersheds,2nd Edition(Technical Release Number 55),US SCS,1986 2. Worksheet modified to conform with Section 3.5.2 of the King County Surface Water Design Manual I 013893/2220/engr-Kbcalc17.xls[Post-Basin B-3] 9/8/98 Sverdrup Civil,Inc. l i 9/9/98 11 :4 :44 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN B, SUB-BASIN B-3 BASIN SUMMARY BASIN ID: DB-3-10 NAME: BASIN B, SUB B-3 , POST, 10YR SBUH METHODOLOGY TOTAL AREA 4 .20 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 90 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: ! 0 . 20 PEAK RATE: 2 . 12 cfs VOL: 0 . 70 Ac-ft TIME: 480 min BASIN ID: DB-3-100 NAME: BASIN B, SUB B-3 , POST, 100YR SBUH METHODOLOGY TOTAL AREA 4 . 20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL ;TYPE KC24HR PERV IMP PRECIPITATION 3 . 90 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 3 . 13 cfs VOL: 1 . 02 Ac-ft TIME : 480 min BASIN ID: DB-3-2 NAME: BASIN B, SUB B-3 , POST, 2YR SBUH METHODOLOGY TOTAL AR A 4 .20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 . 00 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 1 . 26 cfs VOL: 0 .43 Ac-ft TIME: 480 min BASIN ID: DB-3-25 NAME: BASIN B, SUB B-3 , POST, 25YR SBUH MET4ODOLOGY TOTAL AREA 4 . 20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 3 .40 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL I 10 . 00 min CN 83 . 44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF : 0 . 20 PEAK RATE: 2 . 62 cfs VOL: 0 . 86 Ac-ft TIME : 480 min 9/9/98 11 :4 :44 am . Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEVELOPMENT BASIN B, SUB-BASIN B-3 BASIN SUMMARY BASIN ID: DB-3-5, NAME: BASIN B, SUB B-3 , POST, 5YR SBUH METHODOLOGY TOTAL AREA 4 .20 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION 2 .40 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL. . ... : 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFIF: 0 .20 PEAK RATE: 1 . 64 cfs VOL: 0 . 55 Ac-ft TIME: 480 min BASIN ID: DB-3-50 NAME: BASIN B, SUB B-3 , POST, 50YR SBUH METHODOLOGY TOTAL AREA 4 .20 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE . • KC24HR PERV IMP PRECIPITATION 3 .45 inches AREA. . : 2 . 19 Acres 2 . 01 Acres TIME INTERVAL 1 • 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 I PEAK RATE: 2 . 67 cfs VOL: 0 . 88 Ac-ft TIME: 480 min BASIN ID: DB-3-WQ NAME: BASIN B, SUB B-3, POST, WQ SBUH METHODOLOGY TOTAL AREA 4 .20 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE KC24HR PERV IMP PRECIPITATION. . . . : 0 . 67 inches AREA. . : 2 . 19 Acres 2 . 01 Acres : ' TIME INTERVAL 10 . 00 min CN 83 .44 98 . 13 TC 8 . 00 min 8 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 26 cfs VOL: 0 . 09 Ac-ft TIME : 480 min j I ' APPENDIX D I I I I Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Ine. 014002\2220\wp\dmrpt0l.doc Appendix D September 1998 APPENDIX D RETENTION/DETENTION CALCULATIONS This appendix contains' all project retention/detention calculations mentioned in Section IV(D) of this Report. The appendix contains the following summary information: Table D.1 is a'icomparison of hydrologic values as described in Section IV(D). The last column in the table is the combined outflow to Springbrook Creek. Comparison iof the data in the last column, among the five scenarios (baseline, post-CSTC, post-25-20, post 25-10, and post SWMP projects) indicates that even after completion of this project, the total outfall to Springbrook Creek is less than when'Boeing purchased the property. Such a baseline can be utilized should additional work be proposed at the site. Figure D.1 is a chart of the last column in Table D.1 graphically indicating the decrease in peak outflows to Springbrook Creek. Table D.2 summarizes the pre- and post SWMP Basin A, Sub-Basins A-1 and A-2 peak inflow and outflow runoff rates. Figure D.2 is a chart of Table D.2 graphically indicating the decrease in peak outflows from Basin A, Sub-Basins A-1 and A-2. Table D.3 summarizes pre- and post SWMP Basin A peak inflow and outflow runoff rates. I Figure D.3 is a chart of Table D.3 graphically indicating the decrease in peak outflows froth Basin A. Table D.4 summarizes pre- and post SWMP Basin B peak inflow and outflow runoff rates. Figure D.4 is a chart of Table D.4 graphically indicating the decrease in peak outflows from Basin B. This appendix also contain's the following detailed information: 1. Post-Development CSTC project Basin 3 - CSTC Site Basin a. Sub-Basins A-1 and A-2 Routed Level Pool Table Summary b. Basin 3 Release Rates to Springbrook Creek Level Pool Table Summary 2. Post-Development 25-20 project Basin 3 - CSTC Site Basin a. Sub-Basins A-1 and A-2 Routed Level Pool Table Summary Surface Wate i Management Project Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\tp\dmrpt01.doc Appendix D-.1 September 1998 b. Basin 3 Release Rates to Springbrook Creek Level Pool Table Summary 3. Pre-Development SWMP project (Post-Development 25-10 project) Basin 3—CSTC Site Basin .. a. ISub-Basins A-1 and A-2 Routed Routing Comparison Table Stage - Storage Table Stage-Discharge Table I Detailed Discharge:Structure Analysis Level Pool Table Summary b. Basin 3 Release Rates to Springbrook Creek Routing Comparison Table I Stage - Storage Table Stage -Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary 4. Pre-Development SWMP project (Post-Development 25-10 project) Basin4—CSTC Site Basin a. Sub-Basins 4-1 and 4-4 Routed Through Main Track Swale Routing Comparison Table Stage - Storage Table Stage -Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary b. Sub-Basin 4-5 Routed Through Pond "B" Routing Comparison Table Stage - Storage Table Stage -Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary c.Sub-Basins 4-1, 4-4,and 4-5 Routed to Practice Track Routing Comparison Table Stage - Storage Table Stage -Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt01.doc Appendix D-2 September 1998 d. Sub-Basin 4-6 Routed Through Pond "C" Routing Comparison Table Stage - Storage Table Stage -Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary e. Basin 4 Release Rates to Springbrook Creek Routing Comparison Table Stage - Storage Table Stage -Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary 5. Post-Development SWMP Basin A—CSTC Site Basin a. Sub-Basins A-1 and A-2 Routed Through CSTC Pond to Delta Routing Comparison Table Stage- Storage Table Stage-Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary b. Basin A Release Rates to Springbrook Creek Routing Comparison Table Stage - Storage Table Stage -Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary 6. Post-Development SWMP Basin B—CSTC Site Basin a. Sub-Basin B-3 Routed Through Pond "C" Routing Comparison Table Stage - Storage Table _ Stage-Discharge Table Detailed Discharge Structure Analysis Level Pool Table Summary b. Basin B Release Rates to Springbrook Creek Routing Comparison Table Stage - Storage Table Stage - Discharge Table. Detailed Discharge Structure Analysis Level Pool Table Summary Surface Witter Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt01.doc Appendix D-3 September 1998 i i The Boeing Company Surface Water Management Project Site Development II TABLE D.1-COMPARISON OF HYDROLOGIC VALUES Pre-Development,CSTC,Building 25-20,Building 25-10,and SWMP p 111 Pre-Development Baseline Peak Flows and Elevations 1 Combined Outflow ' I STORM Peak Runoff Uncontrolled 1 to Spdngbrook FREQUENCY 1 without routing through detention storage) 2 3 4 5 16 Creek 2 13(c(s) I 4(c(s) 5 6 Outflow Elev. Outflow Elev. Outflow Elev. Outflow Elev. Outflow Elev. cfs) till,' cis) 1 12 31 Total 1 2 13 4 2520 6 1 Total (els) (cis) (els) (NGVD) (cis) (NGVD) (cis) (NGVD) (c(s) (NGVD) (cis) (NGVD) II 5-Year 1.42 23.59 Na Na 2.08 0.46 0.20 0.14 0.63 Na Na 1.45 0.59 ; 0.38 0.63 '8.45 18.55035 7.7H 9.17 54 • 13.95 3.49 /161 3L98 ! Water Qualm 0.20 2.08 Na_ N - 9.15 2-Year 24-Hour 1.12 17.83 il/a Na 17.83 4.83 2.07 2.08 7.13 rile Na 1 16.11 4.50 7.61 0.50 9.35 15.14 10.13 _ 6.19 9.17_ 1.17 13.84 2.70 11.54 25.70 1 e 23.59. 6.37 2.76 '2.80 9.54 _ Na - Na '21.47 5.86 a 10-Year 24-Hour 1.80 31.02 ri/a Na 31.02 8.36 3.66 3.74 12.67 Na Na I 28.43 7.60 13.99 0.78 9.51 22.16 10.57 9.86 9.17 2.02 14.05 4.54 1 11.71 39.36 25-Year 24-Hour 2.18 38.62 Na Na 38.62 10.37 4.57 4.70 15.86 rileNa 35.50 9.36 17.70 0.92 9.53 25.33 10.76 11.73 9.18 2.52 14.12 5.65 11.82 46.15 II' 50•Year24-Hour .222 39.39 rile Na 39.39 10.57 4.66 -4,79 16.18 rile' Na 36.20.-- 9.53' •18.07 , '.0.93 9,53 : 25.63 10.78. 12.05 . 9.18 2.57- 14.13 -5.76 ; "11.83 46.94 Ii 100-Year 24-Hour 2.56 46.31 r}/a N3 46.31 12.39 5.49 5.66 19.09 Na Na 42.63 11.13 21.45 1.05 9.55 28.30 10.94 13.85 9.18 3.03 14.20 6.80 11.92 53.03 11 I Poost-Development CSTC Peak Flows and Elevations IIICombinedOutflowI STORM Peak Runoff Uncontrolled to Springbrook FREQUENCY without routing through detention storage) 2 A B 5 1 6 Creek 2 I A(cfs)I I B(c(s) 5 6 Outflow Elev. Outflow Elev. Outflow Elev. Outflow Elev. Outfloel Elev. c(s) cis) 1 12 Total 1 2 13 4 2520 6 I Total (cfs) (cis) (cis) (NGVD) (cfs) (NGVD) (c(s) (NGVD) (cis) (NGVD) (els) I (NGVD)ilWaterQuality0.21 Na 4.41 0.8 4.59 0.53 0.22 b.14 0.63 Na Na I 1.52 0.59 0.42 0.09 9.10 0.00 __ 7.60 _ 1.01 9.15 0.15 13.54 0.27_- 11.06 __ 1.52 __ 2-Year24-Hour 1.13 Na 23.74 1. 1 25.45 5.30 2.32 2.08 7.13 Na Na 16.83 _4.50 7.61 0.49 9.35 1.89 8.64 6.45 9.17 1.17 13.84 2.70.1_ 11.54 12.70 r 1_...- 954 ' _ _._.._._.-..._........._.........._.....5•Yeer 24-Hour 1.43 Na 50,t2 2.4 32.56 7.00 3.10 2.80 9.54 Na. Na 22.44 5.86 10.36 0.63' 9.45 2.95 8.88 '8.13.,_ 9.17 1,54 13.95 3.49_i__ 11.61 16,74 ! 10-Year 24-Hour 1.82 Na 38.22 3.I3 41.65 9.17 4.10 3.74 12.67 Na Na 29.68 7.60 13.99 0.78 9.51 4.22 8.69 10.32 9.18 2.02 14.05 _ 4.54 L 11.71 21.88 , 25-Year 24-Hour 2.20 Na 46.39 4.47 50.86 11.38 5.12 ;4.0 15.86 n/a Na7 I 37.06 9.36 17.70 0.91 9.53 5.53 8.71 12.41 9.18 2.52 14.12 5.65 1 11.82 27.02 50-Year 24-Hour 2.24Na 47.20 4_58 51.78 11.60 5.23 '4,79 16J 8 Na Na'-: 37;80 9.53„ 18.07" 0,92 • 9,53 68 '-.8,72 12,62 9.18 '2;57 14.13 5.76 L 11.83 27,53.5' 11I100-Year24-Hour 2.59 Na 54.58 5.55 60.13 13.60 6.16 5.66 19.09 Na N 1a 44.51 11.13 21.45 1.04 9.55 6.84 8.74 14.44 9.19 3.03 14.20 6.80- 11.92 32.15 i I Post-Development Building 25-20 Peak Flows and Elevations CombinedOutfioxi STORM Peak RJnolt Uncontrolled to Springbrook i FREQUENCY without routing through detention storage) 2 A B 5 16 Creek 2 I A(ci)4 B(cfs) I 5 6 Outflow Elev. Outflow Elev. Outflow Elev. Outflow Elev. Outflow Elev. e(s) cfs) 1 1 2 A Total 1 2 13 4 2520 6 1 Total (c(s) (cis) (cis) (NGVD) (cis) (NGVD) (cis) (NGVD) (cis) (NGVD) Ws)! (NGVD) I'II Water Quality 0.21 Na 4.50 0.18 4.68 0.30 0.08 10.14 0.63 1.05 Na 2.20 0.59 0.42 0.09 - 9.10 0.00 7.60 0.86 9.15 _ 0.15 13.54 0.27 11.06 _ 1.37 _ 2-Year24-Hour 1.13 Na 23.89 1 71 25.60 3.77 1.16 2.08 7.13 4.37 Na 18.51 4.50 7.61 0.49 9.35 1.93 8.64 9.75 9.17 1.17 13.84 - 2.70 11.54 16.04 I 5-Year24-Hour 1.43' Na 30.28____,2 44 32.72 5.02 1.59 2.80' 9.54 5.40 Na '24.35 5.86 10.38., 0.63.' 9.45 2.97 '8.66 11.29, 9.18 1.54 .13.95- 3.49`' 11.61 19.92 10-Year 24-Hour 1.82 Na 38.38 3143 41.81 6.63 2.15 3.74 12.67 6.68 Na 31.87 7.60 13.99 0.78 9.51 4.24 8.69 12.91 9.18 2.02 14.05 4.54 11.71 24.49 _ ! 25-Year24-Hour 2.20 Na 46.55 447 51.02 8.27 2.72 4.70 15.86 7.96 Naa 39.51 9.36 17.70 0.91 9.53 5.55 8.72 14.76 9.19 2.52 14.12 5.65 11.82 29.39 50-Year 24-Hour 224 Na 47.36 4 58 51.94 8.44 2.78 4.79 16.18 8.09 Na 40.28 . 9.53,_ 18.07. 0.92. . 9.53 5.88 •8.72 15.01 ' , 9.19 2.57 ' 14.13 .5.76 i 11.83 29.94 ,I 100-Year 24-Hour 2.59 Na 54.73 5,55 60.28 9.92 3.30 5.66 19.09 9.25 Na 47.22 11.13 21.45 1.04 9.55 6.87 8.74 17.11 9.19 3.03 14.20 _ 6.80 11.92 34.85 I Post-Development Building 25-10 Peak Flows and Elevations(Pre-Development SWMP, 1 II Combined Outlier),I STORM Peak R Irnotf Uncontrolled to Springbrook i FREQUENCY without routing through detention storage) ' , 2 A B 5 16 Creek ',1 2 I A(cfs) I B(cis)5 6 Outflow Elev. Outflow Elev. Outflow Elev.. Outflow Elev. Outflow Elev. efs) c(s) 1 2 3 Total 1 2 1 3 4 5 6 Total (cis) (cfs) (cis) (NGVD) (cis) (NGVD) (cfs) (NGVD) (cfs) (NGVD) (els)II (NGVD) Water Quality 0.21 rile /4.62 021 4.83 0.30 0.08 0.13 0.63 1.05 0.03 2.22 0.59 0.42 0.09 9.10 0.00 7.60 1.02 9.11 0.15 13.54 0.27 11.06 _ 1.53 2-Year 24-Hour 1.13 Na 24.12 1 43 25.55 3.77 1.16 1.90 7.13 4.37 1.26 19.59 4.50 7.61 0.49 9.35 1.64 8.63 10.06 9.21 1.17 13.84 2.70 11.54 16.06 li6-Year 24-Hour 1.43 • Na ' 30.52 1 99 32.51 5.02 1.59 12.55 '9.54 5.40' 1.54, 25.74 '• -5.86 10.38 0.63 9.45 2.86, 8.66 11.63 9.22 1.54 13.95 3.49 1L61•20.15-. 10•Year24-Hour 1.82 rife 38.62 2.75 41.37 6.63 2.15 3.39 12.67 6.68 2.12 33.64 7.60 13.99 0.78 9.51 4.10 8.69 13.41 9.23 2.02 14.05 4.54 11.71 24.85 25-Year24-Hour 50-Year24.Hour 2.24 ' 2.20 Na 46.78 3.56 50.34 8.27 2.72 4.25 15.86 7.96 2.62 Na 47.60 3i64 51.24 ••8.44 2.78 4.33 16.18 8.09. 2.67 TT 42.49 99.53 1807 0.92 mm 9.53 5.49 8.71 15.22 , 924 ' 2.57 14.13 5.761- 11.83 29.96, "i4I' 100-Year 24•Hour 2.59 Na 54.97 4139 59.36 9.92 13.30 5.11 19.09 9.25 3.13 i 49.80 11.13 21.45 1.04 9.55 6.63 8.74 17.30 9.26 3.03 14.20 6.80 11.92 34.80 ! Post-Development Surface Water Management Project Peak Flows and Elevation: i Combined Outflo v, STORM Peak fjunoft Uncontrolled I to Springbrook, FREQUENCY without routing'through detention storage) 1 2 ' A B 5 II 6 Creek !I I 2 I A 1 B(c(s) 5 6 Outflow Elev. Outflow Elev. Outflow Elev. Outflow Elev. Outflow Elev. cfs) ' cfs) 1 1 2 3 Total 1 2 I 3 4 5 6 I 'Total (cfs) (els) (cis) (NGVD) (cfs) (NGVD) (cfs) (NGVD) (cis) (NGVD) (c(ss (NGVD) Water Quality 0.21 2.32 4.38 -0.21 6.91 0.08 0.13 0.26 Na_ Na Na 1 0.47 0.59 0.42 0.09 9.10 0,00 7.80 - 0.00 7.27 0.15 13.54 0.2 I 11.06 0.51 2-Year24-Hour 1.13 19.57 23.64 '.42 44.63 1.16 1.90 1.26 Na Na_ Na 4.32 4.50 7.61 0.49 9.35 5.29 8.71 1.59 9.12 1.17 13.84 2.70 11.54 11.24 8-Year 24-Hour 1.43 25.63 '30.02 9 2,55957.64 1.69 I 1.00 Na Na Na 5_14. 5_86 10.38 0,63, 9.459.45 7.31_ 8.75 : 2.90 , 9,14 _' 1.54 13.95 - 3.46 11.81 - 15.87', I Iiiipf 10-Year 24-Hour 1.82 33.40 '38.11 t.75 74.26 2.15 3.39 11.64 Na ala Na 7.18 7.60 13.99 0.78 9.51 10.32 8.81 4.52 9.16 2.02 14.05 4.54 11.71 22.18 1a 25-Year 24-Hour 2.20 41.27 46.28 1.55 91.10 2.72 4.25 I 2.62 Na Na Na 289.59 9.36 17.70 0.91 9.53 13.72 8.89 7.48 9.20 2.52 14.12 5.65 11. 30.28 50-Year24•Hour 2.24 42,07 :47.09 :1.63 92,79 2,78 4,33 i 2.67 Na' ,Na '' MI, , 9.78 9.53 18.07 0.92_,__ 9.53 14,05 8.89 7.63 9,19 - 2.57 14,13 5.76 11.83 30,93 _ 100-Year 24-Hour 2.59 49.21 154.47 .38 108.06 3.30 5.11 13.13 Na Na Na 1 11.54 11.13 21.45 1.04 9.55 17.85 8.97 9.05 9.21 3.03 14.20 6.80 11.92 _ 37.77- 1 1 111 I I I I 1 I 1 II 1 1 ' P:f)ob/013747/2210/engr-I<bcalc20 xls[Table D.1] I Drainage Report-Table D.1 9/14/98 Sverdrup Civi I Inc. I 1 1 Combined Outflow to Springbrook Creek Discharge vs Recurrence Event 60.00 Baseline 0—Post CSTC Development i e—Post 25-20 Development i n x--Post 25-10 Development x—Post SWMP Development o---- -- --------' 40.00 e''100-Year Event U 03 a 20.00 viii"i Water Quality Event 0.00 - i 1 2 5 10 25 5 100 Recurrence Interval for 24-Hour Storms (years) 013747/2210/engr-Kbcalc20.xls[Chart D.1] Drainage Report- Figure D.1 9/14/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project Pre-Development SWMP Basin A (Post-Development Building 25-10) Sub-Basin A-2 Routed Through CSTC Pond to Delta Area Existing Site Outflow Under Existing Conditions Storm Peak Inflow Peak Outflow Decrease In Release;Rate Outflow/Inflow.;:,' ;-' ,Peak Stage', '-i Frequency- - - - (cfs),- cfs)-,- - .: ._..;--,,_-- -:(cfs) _-_ ,-- -. ;.-(percent) --., , s..._(elevation) Water Quality 4.62 0.00 4.62 0% 8.69 2-Year 24-Hour 24.12 1.69 22.43 7% 9.20 5-Year 24-Hour 30.52 2.51 28.01 8% 9.31 10-Year 24-Hour 38.62 3.62 35.00 9/0 9.43 25-Year 24-Hour 46.78 4.77 42.01 10% 9.54 50-Year 24-Hour 47.60 4.88 42.72 10% 9.55 100-Year 24-Hour 54.97 5.90 49.07 11% 9.63 Post-Development SWMP Basin A Sub-Basin A-1 & A-2 Routed Through CSTC Pond to Delta Area Developed Site Outflow Under Proposed Conditions Storm ; PeakInflow Peak:Outflow s Decrease.In Release Rate: Outflow/Inflow Peak Stage Frequency cfs)< " : cfs) cfs)": . ;.:..': :,percent)" " : : ,(elevation);" ;: . Water Quality 6.70 0.18 6.52 3%8.82 2-Year 24-Hour 43.21 5.02 38.19 12% 9.56 5-Year 24-Hour 55.65 6.93 48.72 12% 9.71 10-Year 24-Hour 71.51 9.79 61.72 14% 9.89 25-Year 24-Hour 87.55 12.98 74.57 15% 10.05 50-Year 24-Hour 89.16 13.29 75.87 15% 10.07 100-Year 24-Hour 103.67 17.15 86.52 17% 10.20 013747\2210\engr\Kbcalc2l.xls-Table D.2 Drainage Report-Table D.2 9/14/98 Sverdrup Civil, Inc. J Basin A-1 &A-2 Discharge my Recurrence Event for Pre-and t SINWP 2 OO - i 2O8O GVV Pruuu,/vpm n 0-'Pre-Development SVVMP 18.00 - 18l0 14.OD - F- | ---- 5 i12I0 - 10.00 10O'YmarEventCU o' 8.00 i --'i' 61X0 41]O VVober{3mddvEvent 2.00 - O]}O ° 1 2 5 10 25 5 100 Recurrence Interval for 24'Hour Storms kx*orsA o1n747/2o1meng,'nboovo1.xIs[Chart o.2] Drainage Report' Figure O.2 9/14/e8 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project Pre-Development SWMP Basin A (Post-Development Building 25-10) Basin A Routed Through Delta Area to Springbrook Creek Existing Site Outflow Under Existing Conditions Storm Peak Inflow Peak Outflow;• •DecreaSe In ReleASe Rate ;OutflOW/Inflow- ::: -,Peak Stage:: Frequency- - cfs) cfs)- - - -' -: -(Cfs) '" - . .. '(percent): ; ., -- ,(elevatIOn) -. Water Quality 0.21 0.00 0.21 0% 7.60 2-Year 24-Hour 2.00 1.64 0.36 82% 8.63 5-Year 24-Hour 2.90 2.86 0.04 990/0 8.66 10-Year 24-Hour 4.13 4.10 0.03 99% 8.69 25-Year 24-Hour 5.39 5.37 0.02 100% 8.71 50-Year 24-Hour 5.51 5.49 0.02 100% 8.71 100-Year 24-Hour 6.67 6.63 0.04 99% 8.74 Post-Development SWMP Basin A Basin A Routed Through Delta Area to Springbrook Creek. Developed Site Outflow Under Proposed Conditions Storm . - , 'Peak Inflow , s Peak Outflaw r : Decrease In Release Rate '': OutflowfinfloW.„ ,, : -::Peak Stage : Frequency• : .. .: : (cfs) ' cfs) . --. - . : ' (cfs) : ''' r : . • .- (percent) ': ; ."(elevation) - Water Quality 0.22 0.00 0.22 0% 7.80 2-Year 24-Hour 5.33 5.29 0.04 99% 8.71 5-Year 24-Hour 7.33 7.31 0.02 100% 8.75 10-Year 24-Hour 10.36 10.32 0.04 100% 8.81 25-Year 24-Hour 13.73 13.72 0.01 100% 8.89 50-Year 24-Hour 14.08 14.05 0.03 100% 8.89 100-Year 24-Hour 18.13 17.85 0.28 98% 8.97 013747\2210\engr\Kbcalc21.xls-Table D.3 Drainage Report-Table D.3 9/14/98 Sverdrup Civil,Inc. Basin A Discharge vs Recurrence Event for Pre-and Post-Development SWMP 20.00 - 18.00 Pre-Development SWMP Post-Development SWMP 16.00 i 14.00 12.00 100-Year Event 10.00 -. ... . Water Quality Event co i 8.00 - 6.00 -S 4.00 1 2.00 0.00 1 2 5 10 25 50 100 Recurrence Interval for 24-Hour Storms (years) 013747/2210/engr-Kbcalc2l.xls[Chart D.3] Drainage Report- Figure D.3 9/14/98 Sverdrup Civil,Inc. The Boeing Company Surface Water Management Project Pre-Development SWMP Basin B All Sub-Basins Routed Through Practice Track to Springbrook Creek Existing Site Outflow Under Existing Conditions Storm ' Peak Inflow ' Peak Outflow , : Decrease In:Release Rate . Outflow/Inflow • -,Peak Stage Frequency-* • -(Cfs)- : cfs) , - elevatiOn)-, --•-- - -- Water Quality 1.27 1.02 0.25 80% 9.11 2-Year 24-Hour 10.06 10.06 0.00 100% 9.21 5-Year 24-Hour 11.63 11.63 0.00 100% 9.22 10-Year 24-Hour 13.41 13.41 0.00 100% 9.23 25-Year 24-Hour 14.99 14.99 0.00 100% 9.24 50-Year 24-Hour 15.22 15.22 0.00 100% 9.24 100-Year 24-Hour 17.30 17.30 0.00 1.00% 9.26 Post-Development SWMP Basin B All Sub-Basins Routed Through Practice Track to Springbrook Creek Developed Site Outflow Under Proposed Conditions Storm Peak Inflow Peak Outflow .: Decrease In Release Pate OUfflOW/Inflow. • : peak Stage . . Frequency .: ': (cis), ' 'cfs)1 -:: ,;(cfs) ;. percent) , : "elevation) Water Quality 0.44 0.00 0.44 0% 7.27 2-Year 24-Hour 3.37 1.59 1.78 47% 9.12 5-Year 24-Hour 4.45 2.90 1.55 65% 9.14 10-Year 24-Hour 5.87 4.52 1.35 77% 9.16 25-Year 24-Hour 7.48 7.48 0.00 100% 9.20 50-Year 24-Hour 7.64 7.63 0.01 100% 9.19 100-Year 24-Hour 9.05 9.05 0.00 100% 9.21 013747\2210\engr\Kbcalc21.xls-Table D.4 Drainage Report-Table D.4 9/14/98 Sverdrup Civil, Inc. r-- ' Basin B Release Rates &mSprimgbrook Creak Dischargeps Recurrence Event for Pre-and Post—Development SWMP 18.00 o-Poat-Deve|opn ontSVVMP 1GlX} - P-Oaveopn er SVV P 12lD0 C 10J00 10U'Yemr Event as 5 8l0 03 m u- GJ)O WaterQuality ^^~^^ 4lD) i2l]D CiO0 1 2 5 10 26 50 100 Recurrence Interval for 24-HourStorms (years) 013747/221u/eng,'Kbcalc21As[ChartDAJ Drainage Report' Figure O.4 9/14/98 Sverdrup Civil,Inc. 9/11/98 10 : 58 :31 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST CSTC, BSN A-2 ROUTED TO DELTA LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) 1 WQ, POST CSTC A-2 0.00 4.41 CSTC V-WEIR 8.68 8 0.00 70757.20 cf 2YR, POST CSTC A-2 0.00 23.74 CSTC V-WEIR 9.19 9 1.66 6 ac-ft 5YR, POST CSTC A-2 0.00 30.12 CSTC V-WEIR 9.30 10 2.46 8 ac-ft 10YR, POST CSTC A-2 0.00 38.22 CSTC V-WEIR 9.43 11 3.57 9 ac-ft 25YR, POST CSTC A-2 0.00 46.39 CSTC V-WEIR 9.54 12 4.72 10 ac-ft 50YR, POST CSTC A-2 0.00 47.20 CSTC V-WEIR 9.55 13 4.83 10 ac-ft 100YR, POST CSTC A-2 0.00 54.58 CSTC V-WEIR 9.63 14 5.86 11 ac-ft oS-t CS1-Cr 13Aspnj 'A-a Rou-TED 'CNRuvvH CSTTL POND W E1 1 1 o DELTA pv£R ^No'Cc1a I 9/11/98 10 : 56 :34iam Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST CSTC, BSN A ROUTED TO SPRINGBROOK LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, POST CSTC A 0.00 0.18 DELTA PSTA 7.60 1 0.00 6984.20 cf 2YR, POST CSTC A 0.00 2.07 DELTA PSTA 8.64 2 1.89 91699.78 cf 5YR, POST CSTC A 0.00 2.99 DELTA PSTA 8.66 3 2.95 93659.95 cf 10YR, POST CSTC A 0.00 4.26 DELTA PSTA 8.69 4 4.22 96005.13 cf 25YR, POST CSTC A 0.00 5.56 DELTA PSTA 8.71 5 5.53 98422.64 cf 50YR, POST CSTC A 0.00 5.69 DELTA PSTA 8.72 3 5.66 98665.19 cf 100YR, POST STC A 0.00 6.89 DELTA PSTA 8.74 7 6.84 2 ac-ft ppg ( - OEVLOC,McnY CS TC. BASIN) A- ; A-3 R v-rEo "THAo coo fl p15G HARG E VAvLT 1'1) 5P IfoG ?Root. GKEsK E_ (EAR -tA,L.r1 a, = g. 60 I i I 9/11/98 11 : 0 :18 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST 2520, BSN A2 ROUTED TO DELTA LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) I WQ, POST 2520 A-2 0.00 4.50 CSTC V-WEIR 8.69 8 0.00 71726.18 cf 2YR, POST 2520 A-2 0.00 23.89 CSTC V-WEIR 9.19 9 1.67 6 ac-ft 5YR, POST 2520 A-2 0.00 30.28 CSTC V-WEIR 9.31 10 2.48 8 ac-ft 10YR, POST 2520 A-2 0.00 38.38 CSTC V-WEIR 9.43 11 3.59 9 ac-ft 25YR, POST 2520 A-2 0.00 46.55 CSTC V-WEIR 9.54 12 4.74 10 ac-ft 50YR, POST 2520 A-2 0.00 47.36 CSTC V-WEIR 9.55 13 4.85 10 ac-ft 100YR, POST 2520 A-2 0.00 54.73 CSTC V-WEIR 9.63 14 5.88 11 ac-ft p65-7 -oevE'LoPt'taN1 emLOrn)G g25-Q0 QASrti A-3 Rov-rro T14aooG4L Cs-cc. PO^ip nvark V— NoTL.N J IR. To DEL,TA AREA 9/11/98 11 : 6 :58 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST 25210, BSN A ROUTED TO SPRINGBROOK j LEVEL POOL TABLE SUMMARY I I i MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) 1 I WQ, POST 2520 A 0.00 0.18 DELTA PSTA 7.60 1 0.00 6984.20 cf 2YR, POST 2520 A 0.00 2.08 DELTA PSTA 8.64 2 1.93 91772.36 cf 5YR, POST 2520 A 0.00 3.01 DELTA PSTA 8.66 3 2.97 93695.80 cf 10YR, POST 2520 A 0.00 4.28 DELTA PSTA 8.69 4 4.24 96044.24 cf 25YR, POST 2120 A 0.00 5.58 DELTA PSTA 8.72 5 5.55 98460.73 cf 50YR, POST 2520 A 0.00 5.71 DELTA PSTA 8.72 6 5.68 98702.82 cf 100YR, POST 2520 A 0.00 6.93 DELTA PSTA 8.74 7 6.87 2 ac-ft i I 9Dy- OE LO?M E,J1 Q -a a t3A5tN A-a 4 A 3 ftov-rEQ c-kftvv614 v 5C.HAi.GE. VAVL'T -rD Sf(kifoGd(Lootc- c.12.E14. II i I 1 ID File Input Hydrograph Storage Discharge LPool Proj : SWMP IeeeeeeeeeeeeeeeeeeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeee ;, o MATCH INFLOW STO DIS PEAK PEAK OUT 0 o . DESCRIPTION PEAK PEAK No.No. STG OUT HYD o o- WQ, PRE SWMP A-2 0 . 00 4 . 62 CSTC V-WEIR 8 . 69 0 . 00 1 2YR, PRE SWMP A-2 0 . 00 24 . 12 CSTC V-WEIR 9 .20 1 . 69 2 5YR, PRE SWMP A-2 0 . 00 30 .52 CSTC V-WEIR 9 .31 2 . 51 3 0 10YR, PRE SWMP A-2 0 . 00 38 . 62 CSTC V-WEIR 9 .43 3 . 62 • 4 j 25YR, PRE SWMP A-2 0 . 00 46 . 78 CSTC V-WEIR 9 . 54 4 . 77 5 0 50YR, PRE SWMP A-2 0 . 00 47. 60 CSTC V-WEIR 9 . 55 4 . 88 6 0 100YR, PRE SWMP A-2 0 . 00 54 . 97 CSTC V-WEIR 9 . 63 5 . 90 7 o c o 0 o a o O Done< Press any key to exit aeeeeeeeeeeeeeeeeeeeeeeee'eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef Menu: Perform Level pool computations using input table instructions I -, R5 - O LO PiAgArr St7RFA.ce WPtiEN t'IP0"EKEPI- ?O SEcr C Pos-c -o..et.oP MEI. 9„ as 1 QASin/ Pci^ RA v T EO i t tp.o 6N CS'SC P oNp Ov E!t v^Nkc.4t WEtI To DGL'CA AR.tA . 9/14/98 7 :32 :34 at Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE SWMP, BSN A-2 ROUTED TO DELTA STAGE STORAGE TABLE CUSTOM STORAGE ID No. CSTC Description: CSTC STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (fl) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 8.50 0.0000 0.0000 9170 502749 11.542 10.90 1116440 25.630 12.10 1865645 42.829 8.60 38363 0.8807 9.80 547168 12.561 11.00 1169821 26.855 12.20 1936568 44.457 8.70 76726 1.7614 9.90 591587 13.581 11.10 1232311 28.290 12.30 2007492 46.086 8.80 115089 2.6421 10100 636006 14.601 11.20 1294801 29.725 12.40 2078415 47.714 8.90 15352 3.5228 10110 689388 15.826 11.30 1357291 31.159 12.50 2149339 49.342 9.00 191315 4.4035 10120 742769 17.052 11.40 1419781 32.594 12.60 2220262 50.970 9.10 236234 5.4232 10130 796151 18.277 11.50 1482271 34.028 12.70 2291186 52.598 9.20 280653 6.4429 10140 849532 19.503 11.60 1544761 35.463 12.80 2362109 54.227 9.30 325072 7.4626 10.50 902914 20.728 11.70 1607251 36.897 12.90 2433033 55.855 9.40 369491 8.4824 10.60 956295 21.954 11.80 1669741 38.332 0.00 2503956 57.483 9.50 413911 9.5021 10.70 1009677 23.179 11.90 1732231 39.767 9.60 458330 10.522 10 180 1063058 24.404 12.00 1794721 41.201 J i I i1 9/14/98 7 :32 :34 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE SWMP, BSN A-2jROUTED TO DELTA STAGE DISCHARGE TABLE CUSTOM DISCHARGE ID No. V-WEIR Description: V-WEIR STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs I 8.70 0.0000 i9.50 4.2774 10.30 122.54 11.10 201.82 8.80 0.1450 I9.60 5.4425 10.40 131.57 11.20 212.82 8.90 0.3801 19.70 6.7779 10.50 140.86 11.30 224.04 9.00 0.7102 9.80 8.2911 10.60 150.41 11.40 235.49 9.10 1.1534 9.90 9.9894 10.70 160.21 11.50 246.33 9.20 1.7218 10.00 11.880 10.80 170.25 9.30 2.4256 10.10 13.969 10.90 180.54 9.40 3.2746 10.20 16.264 11.00 191.06 I I I I 1 i I I f _' I. a FROM IFROILITIES TO a 06 822 3300 1SsS.06-02 07sSSRM #877 P.01/02 4.571/171i fgif/J 1/4.....; 6 Gr. 0, aliagnirsj %Ia.% , UP MT 10 3S Van -sk goon 1 Matuttle, dear ?Atm.& Elba. iIt 0 t liii 1 Iry1 Sisvoi mac " nil • I - k i.UT is all S.Ztrel- g, # to rettasure. Dlegiek H. iiiiiiegni 74" st t 3-", i.# is- # , not' cl-v>„,,, 1/1 Svur.Inke cats! ilk. ins-, s a L1 Ju. 40 ckt#pen. o+.- ea. non- a ne tol p u i , a t hartnia. ,* -1 vw. q.x, kt. et (vu Pkic ta+eat o S" S _ 1 r 4 1 '`n rya R.+i11u- dP ' I MO:MVO S 9/14/98 7 :32 :36, am Sverdrup Civil. Inc page 3 _ THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE SWMP, BSN A-2; ROUTED TO DELTA LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, PRE SWMP A-2 0.00 4.62 CSTC V-WEIR 8.69 1 0.00 73087.41 cf 2YR, PRE SWMP A-2 0.00 24.12 CSTC V-WEIR 9.20 2 1.69 6 ac-ft 5YR, PRE SWMP A-2 0.00 30.52 CSTC V-WEIR 9.31 3 2.51 8 ac-ft 10YR, PRE SWMP A-2 0.00 38.62 CSTC V-WEIR 9.43 4 3.62 9 ac-ft 25YR, PRE SWMP A-2 0.00 46.78 CSTC V-WEIR 9.54 5 4.77 10 ac-ft 50YR, PRE SWMP A-2 0.00 47.60 CSTC V-WEIR 9.55 6 4.88 10 ac-ft 100YR, PRE SWMP A-2 0.00 54.97 CSTC V-WEIR 9.63 7 5.90 11 ac-ft 1 I I I 1 III I? File Input Hydrograph Storage . Discharge LPool Proj . SWMP 5eee"eeeeeeeeeeeeeeeeeee0eeRouing Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeee ; MATCH INFLOW STO DIS PEAK PEAK OUT , ESCRIPTION PEAK PEAK No. - No_STG OUTUT HYDYD 0 . 46, •RE SWMP A 0 . 00 0 . 21 DELTA .PSTA 7 . 60 0 . 00 8 2YR, PRE SWMP 'A 0 . 00 2 . 00 DELTA PSTA 8 . 63 1 . 64 9 0 SYR, PRE SWMP A 0 .,00 • 2 . 90 DELTA PSTA 8 . 66 2 . 86 10 0 10YR, PRE SWMP A 0 . 00 4 . 13 DELTA PSTA 8 . 69 4 . 10 11 0 25YR, PRE SWMP A 0 . 00 5 . 39 DELTA PSTA 8 . 71 5 .37 12 0 50YR, PRE SWMP A 0 . 00 5 . 51 DELTA PSTA 8 . 71 5 .49 13 100Y' , PRE SWMP A 0 . 00 6 . 67 DELTA PSTA 8 . 74 6 . 63 14 0 0 0 0 0 0 Done< Press any key to exit ; 0 Apeee=eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-eeeeeef enu: Perform Level pool computations using input table instructions RE_ pCvCL-O9 fr T SutiFacC tivA-Ten- M,AiVACE' t .pdT Pl&cyEcj CQoS1 - 06vELovr'1EtdV l3v«owG aS^' C3ftSIN) kovi. D Vi 614 DCLca 01 C.1414.1tG VP% To • SP(twvBilook L TA%L,WPs'Z62 = e, coo I 9/14/98 7 :39 :14am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE SWMP, BSN A ROUTED TO SPRINGBROOK CR STAGE STORAGE TABLE CUSTOM STORAGE ID No. DELTA Description: DELTA STAGE c----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 7.50 0.0000 0.0000 8.40 70453 1.6174 9.30 157876 3.6243 10.20 265457 6.0940 7.60 6984 0.1603 8.50 79336 1.8213 9.40 169251 3.8855 10.30 279434 6.4149 7.70 13968 0.3207 8.60 88218 2.0252 9.50 180626 4.1466 10.40 293411 6.7358 7.80 20953 0.4810 8.70 97101 2.2291 9.60 192001 4.4077 10.50 307389 7..0567 7.90 27937 0.6413 8.80 105984 2.4331 9.70 203376 4.6689 10.60 321366 7.3775 8.00 34921 0.8017 8.90 114867 2.6370 9.80 214752 4.9300 10.70 335343 7.6984 8.10 43804 1.0056 9.00 123750 2.8409 9.90 226127 5.1912 10.80 349320 8.0193 8.20 52687 1.2095 9.10 135125 3.1020 10.00 237502 5.4523 10.90 363298 8.3402 8.30 61570 1.4134 9.20 146500 3.3632 10.10 251479 5.7732 I i 9/14/.98 7 :39 : 14 'lam Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE SWMP, BSN A ROUTED TO SPRINGBROOK CR I STAGE DISCHARGE TABLE CUSTOM DISCHARGE ID No. PSTA Description: CSTC-OUT I STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) cfi ft) ---cfs ft) ---cfs ft) ---cfs 8.60 0.0000 10i00 41.370 11.40 81.054 12.80 128.54 8.70 4.8150 101110 44.000 11.50 84.120 12.90 132.17 I 8.80 9.6300 10.20 46.630 11.60 87.378 13.00 135.80 8.90 14.445 10130 49.260 11.70 90.636 13.10 139.61 I I 9.00 19.260 10.40 51.890 11.80 93.894 13.20 143.42 9.10 21.378 10150 54.520 11.90 97.152 13.30 147.23 9.20 23.496 10160 57.374 12.00 100.41 13.40 151.04 9.30 25.614 10170 60.228 12.10 103.86 13.50 154.85 I 9.40 27.732 10.80 63.082 12.20 107.31 13.60 158.83 I 9.50 29.850 10190 65.936 12.30 110.76 13.70 162.81 9.60 32.154 11100 68.790 12.40 114.21 13.80 166.80 9.70 34.458 11.10 71.856 12.50 117.66 13.90 170.78 1 9.80 36.762 11.20 74.922 12.60 121.29 14.00 174.76 9.90 39.066 11.30 77.988 12.70 124.92 I I I I II I I I CSTC Delta Area Discharge Vault Summary Basin 3 Discharge Structure to Springbrook Creek) Stage Vault Inlet Capacity Vault Interior Capacity Vault Outlet Capacity Actual Vault ft)(1) Contracted Broad- 18°RCP Total Inlet Broad-Crested Weir 36°DIP Outlet Release Rate Crested Weir(cfs)(2) Inlet(cfs)( 3) Capacity(cfs)( 4) Stoplogs)(cfs)( 5) cfs)( 6) cfs) (7) 8.60 0 0 0 0 0 0 9:00 0 19 19 67 80 19- 9.50 0 30 30 125 124 30 10.00 3 38 41 188 157 41 10.50 10 45 55 259 185 55 11.00 18 51 69 337 210 69 11.50 28 56 84 422 233 84 12.00 39 61 100 514 254 100 12.50 52 66 118 612 273 118 13.00 65 70 136 717 291 136 13.50 80 75 155 828 309 155 14.00 96 79 175 946 325 175 Notes: 1) 2-year tailwater in Springbrook Creek=8.60 (Table 8-2, ESGRWSP, R.W. Beck, Dec 1996) 2) Refer to CSTC Delta Area Discharge Vault Element 1 for details. 3) Refer to CSTC Delta Area Discharge Vault Element 2 for details. 4) Total vault inlet capacity is sum of contracted broad-crested weir(2) capacity and 18" RCP(3) capacity 5) Refer to CSTC Delta Area Discharge Vault Element 3 for details. 6) Refer to CSTC Delta Area Discharge Vault Element 4 for details. 7) Vault inlet capacity, internal capacity and outlet capacity were compared to determine the actual release rate from the vault. 0 1 3747122 1 0\engr\Kbcalc18.xls[Summary] 16'-0 I 4•-a. IAH OPENING IMHSTEPTYP f L3x3x3/8 I ,- GAL TTYYPP 6'-0'x8'-IT l I BILCO 000R POINT OF IDENTIFYING STOP• I r 1 COORDINATES• I LOOS•-- I I • 3r DIP CL 53 FLOE J. I TO SPRINGBROOK CREEK I /` Iy b 1 I 0 b r I1 1 I• 1 I I Q ^ 1 I 10E4 o)a 11(0) 1Is CONC-/ I •'BOLTED FLANGED JOINT L J CYUNDRICAL WATER INTAKE SCREEN OVERFLOW-' I r• T-60 WITH 1/If SCREEN BYrL'•JOHNSON SCREENS OR APPROVED EQUALOPENMGb:.b NOTE: FOR DETAILS NOT SHOWN1t.I SEE 1S80(D) r PVC DRAIN I I• DIP CAST INTO PVC UNION CONCRETE Z YA2 fvrv/e ,sr I;c ACCESS COVER 2- I . PVC BALL VALVE E ON ,Spe/NGBAa•00/4. OUTLET STRUOOK CREEK C/E/c •eL a• ,OUTLET STRUCTURE SCALE NONE 1C1 e • ') b MH OPENING W%4. 6•-0'x8•-d BIL • j I • (%-.\% \.\" -''\ • I DOOR OPCNING N\.ti ./// 0VIOE REMOVABLE CRA NOTE: W/ 1 •M00TH CALV STEEL BARS AT G OC VERTICAL EL 12.0 EL 15.2. STOP LOG, ANCHOR TO ORIENTA .CONSIST OR 578 0 BOLTS, STOP LOG ANGLE GUI') NUTS AND WASHERS'PASSING r THROUGH BOTH STOP LOG ANGLE GUIDES ON BOTH 2'-0'z3'-0' SIDES WILLOW • 3/IC GALV•WEB r SEE ANC NPW1 OPENINGRW STIFFENER 0 12} OC FOR SP CIES AND TYP II I r SPACING EL 9:5 3C0 OUTLET STOP LOG MACH• 18' SO BEVEL TO I AA.i• + I' ri . LE EL 6.• I.E. EL-5.9 q iiiiii•ii• ••iiO i I.E./ EL-5.40 LE. 0. 4 0.42X 60• .;DIA •••••••• i V PVC i•+:•••r 0.80% DRAM LEEL 3/4 0 EPOxY ANCHOR BOLTS, e. r NUTS AND WASHERS • 4, OO•12' BOC EHT CrIP) 4 . — 4 6%12" TIMBER STOP LOGS a • I' r • r • • Q A r SPRINGBROOK CREEK SECTION OUTLET STRUCTURE SCALE: NONE 1,• ,' • 0) Sou .cE : GSTL S, G Dci‘rEL.DPMENT Sot("\ 0RAINA(E DETA%L.S -SHEET 5 DRA I1N6 c.159C6) r 1 i CSTC-Delta Area Discharge Vault Element 1 2' x 3' Overflow Contracted Broad-Crested Weir) 1 j Stage Hydraulic Weir Coefficient Actual No.of sides Effective Flowrate ft) Head Height C1 (1)Width contracted Width 0(cfs)(3) H(ft) Y(ft) bactuat(ft) N beff.(ft)(2) 9.5 0.0 18.5 0.000 3.0 2 3.00 0 10.0 0.5 8.5 0.615 3.0 2 2.99 3 _ 10.5 1.0 j8.5 0.616 3.0 2 2.98 10 1 11.0 1.5 I8.5 0.620 3.0 2 2.97 18 11.5 2.0 8.5 0.624 3.0 2 2.96 28 12.0 2.5 18.5 0.629 3.0 2 2.95 39 12.5 3.0 18.5 0.633 3.0 2 2.94 52 13.0 3.5 8.5 0.638 3.0 2 2.93 65 13.5 4.0 I8.5 0.643 3.0 2 2.92 80 14.0 4.5 8.5 0.647 3.0 2 2.91 96 Notes: I 1) C1=[0.6035+0.0813(H/)+(0.000295/Y)]*[1+(0.00361/H)J3/2 (Rehbock) 2) beff=bactual-(0.1)(N)(H) 3) Q=2/3(C1)(beff)(2g)1i2(H)312 CSTC Delta Area Discharge Vault Element 3 Submerged Supressed Broad-Crested Weir, Stoplogs) Stage Hyd. Head Hyd. Head Weir Coefficient Actual Flowrate Flowrate ift)(1) Upstream Downstream Height C1 (2) Width Free Flow Submerged Hup(ft) Hdown(ft)Y(ft) actual(ft) Qtree(cfs)(3) ()sub.(cfs)(4) 8.60 1.1 I1.10 6.5 0.620 16.0 61 0 j 9.00 1.5 1.10 6.5 0.625 16.0 98 67 9.5 2.0 I1.10 6.5 0.630 16.0 153 125 10.0 2.5 1.10 6.5 0.636 16.0 215 188 10.5 3.0 11.10 6.5 0.642 16.0 286 259 11.0 3.5 1.10 6.5 0.648 16.0 363 337 11.5 4.0 I1.10 6.5 0.654 16.0 448 422 12.0 4.5 11.10 6.5 0.661 16.0 540 514 12.5 5.0 11.10 6.5 0.667 16.0 638 612 13.0 5.5 i 1.10 6.5 0.673 16.0 743 717 13.5 6.0 11.10 6.5 0.679 16.0 854 828 14.0 6.5 1.10 6.5 0.685 16.0 972 946 Notes: 1 1) 2-year tailwater in Spririgbrook Creek=8.60(Table 8-2, ESGRWSP, R.W. Beck, Dec 1996) 2) C1=[0.6035+0.0813(H/Y)+(0.000295/Y)]11+(0.00361/H)]312 (Rehbock) 3) ()free=2/3(C1)(bactuai)(29)V2(Hup)312 4) °sub=Qfree[1 -(Hdowr/Hup)31 385 1 013893\2220\engr\Xbcalcl8.xls[E1andE3] Page 1 of 3 Pressure Pipe Analysis & Design Circular Pipe orksheet Name: basin 3 pre-dev Description: Basin 3 Outlet 18" RCP Solve For Discharge Given Constant Data; Pressure @ 1 0 . 00 Elevation @ 2 8 .60 — 2.NR. TW At SPRaNQUi4ol c2EEK Pressure @ 1 0 .00 Discharge 45326 .53 Diameter 18 .00 Length 24 .00 Hazen-Williams C 140 . 0000 variaole Input Data Minimum Maximum Increment By Elevation @ 1 8 .60 16 .00 0 .10 BASI(Q "h : 18" RCP INLET -Co CoNTR,ot... STRVc.T\) . CS le.... ck,AN ELErAIQI. I- I Open Channel Flow Module, Version 3 . 11 (c) Haesta Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 i Page 2 of 3 1 VARIABLE COMPUTED Elev. Pressure Elev'. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2; @ 2 gpm in ft 1 ft psi ft 1 psi Unable to compute this instance. 8.70 0 .00 8 .60 0 . 00 4090 .00 18 .00 24 .00 140 .00 8 .80 0 . 00 8 .60. 0. 00 5946 .75 18 .00 24 . 00 . 140 .00 8.90 0 .00 8 . 60 0 .00 7402 .34 18 .00 24 . 00 140 . 00 9. 00 0 .00 8 .60 • 0 .00 8646 .41 18 .00 24 . 00 140 .00 9 .10 0 . 00 8.60 0. 00 9753 .65 18 . 00 24 . 00 140 .00 9.20 0 .00 8 . 60 0 .00 10762.79 18 . 00 24 . 00 140. 00 9.30 0 .00 8 .60 0 .00 11697. 05 18 . 00 24 .00 140 . 00 9.40 0 . 00 8 .69 0.00 12571.64 18 . 00 24.00 140 . 00 9.50 0 . 00 8 .610 0 .00 13397.21 18 .00 24.00 140 .00 9.60 0 . 00 8 .60 0 .00 14181.54 18 .00 24 .00 140.00 i 9.70 0 .00 8 .60 0 .00 14930 .54 18 . 00 24 .00 140 .00 9.80 0 . 00 8 .60 0 .00 15648.81 18 .00 24. 00 140 .00 9. 90 0 .00 8.6,0 0.00 16340 . 03 18 .00 24 .00 140.00 10.00 0 .00 8 .60 0.00 17007.19 18 . 00 24. 00 140 . 00 10.10 0 .00 8.60 0 .00 17652 .76 18 . 00 24 .00 140 .00 10.20 0 . 00 8 .60 0 .00 18278 . 82 18 . 00 24.00 140 .00 10.30 0 .00 8.60 0.00 18887 .12 18 . 00 24.00 140 .00 1.0.40 0 . 00 8.60 0 .00 19479 .17 18 .00 24 .00 140 .00 50 0 .00 8 .60 0 .00 20056 .28 18 . 00 24 .00 140 .00 0.60 0 . 00 8 .60 0. 00 20619 .57 18 . 00 24 .00 140 .00 10 .70 0 . 00 8 .60 0. 00 21170 .04 18 . 00 24 .00 140 .00 10.80 0 .00 8 . 60 0 .00 21708 .59 18 . 00 24 .00 140 . 00 10. 90 0 . 00 8 .60 0 .00 22235 .99 18 . 00 24 .00 140 . 00 11.00 0 . 00 8 .60 0 . 00 22752 . 93 18 .00 24 .00 140 . 00 11. 10 0 . 00 8 . 60 0 .00 23260 . 07 18 .00 24 .00 140 . 00 11.20 0 . 00 8 .60 0 . 00 23757.95 18 . 00 24 .00 140 . 00 11.30 0 .00 8.60 0 . 00 24247.10 18 . 00 24 .00 140 .00 j 11.40 0. 00 8 .60 0 .00 24727.98 18 .00 24.00 140 . 00 11.50 0 . 00 8 .60 0 .00 25201.03 18 .00 24 .00 140.00 11.60 0 .00 8 .60 0.00 25666 .63 18 . 00 24.00 140 . 00 11.70 0 .00 8.60 0.00 26125 .14 18 .00 24.00 140 .00 11.80 0 .00 8 .60 0 .00 26576 . 90 18 . 00 24 .00 140.00 11. 90 0 .00 8 .60 0. 00 27022 .21 18 . 00 24 .00 140 . 00 12.00 0 . 00 8 . 60 0 . 00 27461.36 18 .00 24 .00 140.00 • 12 .10 0 . 00 8 .60 0 .00 27894 . 60 18 . 00 24 . 00 140 . 00 12 .20 0 . 00 8 .60 0 . 00 28322 .18 18 . 00 24 .00 140 . 00 12 .30 0 . 00 8 .60 0 .00 28744 .34 18 . 00 24 .00 140.00 12 .40 0 .00 8 . 60 0 . 00 29161.27 18 . 00 24 . 00 140 . 00 12 .50 0 . 00 8 .60 0 .00 29573 . 19 18 . 00 24 .00 140 . 00 i Open Channel Flow Module, Version 3 .11 (c) Haestad Methods,: Inc. * 37 Brookside Rd * Waterbury, Ct 06708 Page 3 of 3 VA 2IABLE COMPUTED Elev. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @1 @1 @2 ,@2 gpm in ft ft psi4. ft psi 12 . 0 0 .00 8 . 69 0.00 29980.28 18 . 00 24 .00 140 . 00 12 . 0 0 .00 8 .60 0 . 00 30382 .72 18 .00 24 . 00 140 .00 12 . 0 0 . 09 8 .69 0 .00 30780 .66 18 . 00 24 . 00 140 . 0 12. 0 0 .010 8 .60 0 . 00 31174 .27 18 . 00 24 .00 140 .00 13 . 0 0.00 8 .60 0.00 31563 .69 18 .00 24 .00 140 .00 13 . 0 0 .01i0 8 .60 0 . 00 31949 .06 18 .00 24. 00 140 .00 i 13 . '0 0 .00 8 .60 , 0 .00 32330 .51 18 . 00 24 .00 140 . 00 13 . co 0 .00 8 .60 0 .00 32708 .17 18 .00 24 .00 140 .00 113 . 0 0 .0 0 8 .60 0. 00 33082 .14 18 . 00 24 .00 140 . 00 13 . .0 0.0 0 8 .60 , 0 .00 33452 .55 18 .00 24.00 140.00 13 . .0 0 ..010 8 .60 0.00 33819 .50 18 .00 24 .00 140 .00 13 . 0 0.00 8 .60 0 . 00 34183 .08 18 .00 24 .00 140 .00 13 . :0 0 .00 8.60 : 0.00 34543 .41 18 .00 24 .00 140 . 00 13.:0 0 .00 8 .60 0 .00 34900 .55 18 .00 24.00 140.00 14. 10 0 .00 8 .60 0 .00 35254 .62 18 . 00 24.00 140 .00 14.10 0 .00 8 .69 0 . 00 35605 .67 18 .00 24.00 140.00 14.+0 0.00 8 .60 0 .00 35953 .81 18 .00 24.00 140 .00 14.c0 0 .00 8.60 0. 00 36299 .09 18 .00 24 .00 140 . 00 14. , 0 0.00 8 .60 0 .00 36641.60 18 .00 24.00 140 .00 1.50 0 .00 8 .60 0 .00 36981.41 18 .00 24 .00 140 .00 14.60 0 .00 8 .60 0.00 37318 .57 18 . 00 24 .00 140.00 14.70 0 .00 8 .69 0 .00 37653 .16 18 . 00 24.00 140 .00 14 .80 0 . 00 8 .6 0 0 .00 37985.24 18 .00 24 .00 140 .09 14 . 90 0 .00 8 .60 0 . 00 38314 .86 18 .00 24.00 140 . 0 15.00 0 .00 8 .60 0 .00 38642 .08 18 . 00 24 .00 140 .00 15 .10 0 .0I0 8 . 6i0 , 0 .00 38966 . 96 18 . 00 24 . 00 140 .00 15 .20 0 .00 8 .60 : 0 .00 39289 .55 18 . 00 24.00 140 . 00 15 .30 0 .00 8 .610 ' 0 .00 39609. 90 18 .00 24 .00 140.09 15 .40 0 .00 8 .610 0.00 39928 .06 18 .00 24.00 140. 0 15 .50 0.00 8.60i 0 .00 40244 .07 18 .00 24.00 140 .09 15.60 0.00 8 .60 0 .00 40557.98 18 .00 24.00 140 .09 15 .70 0 .00 8 .60 0 .00 40869 .83 18 .00 24 .00 140.00 15.80 0. 00 8 .60 0.00 41179.67 18 . 00 24 .00 140 .09 15. 90 0 .00 8 .60 0 .00 41487.54 18 .00 24.00 140. 00 16 .00 0 . 00 8 .60 0 .00 41793 .47 18 . 00 24 .00 140 .00 • 16 . 10 0 . 00 8 .60 0 .00 42097 .51 18 . 00 24 . 00 140 .00 II Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 iI I Page 1 of 3 Pressure Pipe Analysis & Design Circular Pipe Worksheet Name: basin 3 pre-dev 36" Description: Basin 3 Outlet 36" DIP Solve For Discharge Given Constant Data; Pressure @I1 0 . 00 Elevation @ 2 8 . 60 Pressure @; 1 0 . 00 Discharge 46869 .55 Diameter 36 . 00 Length 44 .00 Hazen-Williams C 130 .0000 Variable Input Data Minimum Maximum Increment By Elevation @ 1 8 .60 16 . 00 0.10 tJa51N - : 3;(:: DIP OvTLET FROM C.o;NTRou SiRocr vtka, 01su4ARGE To SPRir\K,cRoo S cPEEl<, CC51- Oe\\-0.. Nreo, v v` J Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 Page 2 of 3 JAR ABLE COMPUTED Ele . Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @ @ 1 @ 2 @ 2 gpm in ft ft psi ft psi Un ble to compute this instance. 8.70 0 .00 8.60 ; 0. 00 16947.17 36 .00 44 . 00 130 . 00 8 .80 0 .00 8.60 ; 0 .00 24640 .72 36 .00 44 .00 130 . 00 , 8 .90 0 .00I 8 .60 0 .00 30672 . 04 36 .00 44 .00 130 . 00 ' 9 .00 0 .001 8 .60;0 .00 35826 . 93 36 . 00 44 .00 130 . 00 9 .10 0 .00 8 .60;0 .00 40414 . 85 36 . 00 44 . 00 130 .00 9.20 0 .00 8 .60 0 .00 44596 .30 36 . 00 44 . 00 130 . 00 9.30 0 .00 8 .60 0 . 00 48467 .44 36 .00 44 .00 130 .00 ; 9.40 0 .00 8.60 0 . 00 52091.37 36 . 00 44 . 00 130 . 00 9 .50 0.00 8.60 0 .00 55512 .16 36 .00 44 .00 130 . 00 9 . 0 0.00 8.60 0 .00 58762 .08 36.00 44 .00 130 .00 9 . 0 0 .00 8 .60 0.00 61865 .60 36.00 44 .00 130 . 00 9. 0 0 .00 8.60 ; 0.00 64841.80 36.00 44.00 130 . 00 9 . 0 0 .00 8 .60I 0 .00 67705 . 91 36.00 44 . 00 130 . 00 10. 0 0.00 8.60 0 .00 70470.33 36 .00 44 . 00 130 .00 10. 0 0 .00 8.60i 0 .00 73145.31 36.00 44 . 00 130 .00 1 10. 0 0 .00 8 .60 0.00 75739 .42 36 .00 44 .00 130 . 00 10 . 0 0 .00 8 .60 0 .00 78259 . 96 36 . 00 44.00 130 . 00, 1O. 0 0 .00 8.60 0 .00 80713 .16 36 . 00 44 .00 130. 00E 0 0.00 8.69 ' 0 .00 83104 .42 36 .00 44 .00 130 .00 0 . 0 0 .00 8.60 0 .00 85438.45 36 .00 44 . 00 130 . 00 10. 0 0 .00 8.60 0 .00 87719 .39 36 .00 44 .00 130 .00 10. 0 0 .00 8 .60 0 . 00 89950 .88 36 .00 44 . 00 130 . 00 10 . 0 0 .00 8 .60 0 . 00 92136 .18 36 .00 44 . 00 130 . 001 11. 0 0 .00 8 .60 0.00 94278.19 36 .00 44 . 00 130 . 00 11. 0 0 .00 8.60 0 .00 96379 . 53 36 .00 44 . 00 130 . 00' 11. :0 0 . 00 8.60 0 .00 98442 . 54 36 .00 44 . 00 130 . 00 11. 0 0 .00 8.60 0 .00 100469.36 36 . 00 44 .00 130 . 00 11. , 0 0 .00 8 .60 ' 0 .00 102461.93 36 .00 44 .00 130 . 00 il. ' 0 0 .00 8.66 0.00 104422 .02 36 .00 44.00 130 . 90 11. :.0 0 .00 8 .60 0 .00 106351.26 36 .00 44 .00 130 .00 11. '0 0 .00 8.601 0.00 108251.14 36 .00 44 .00 130 .00 11. 0 0 .09 8 .60 0 .00 110123 .03 36 .00 44 .00 130 .90 11. 10 0 . 00 8 .601 0 .00 111968 .20 36 .00 44 .00 130 . 00 12 . 10 0 . 00 8 .60 0. 00 113787.83 36 . 00 44 .00 130 . 00 • 12 . , 0 0 . 00 8 .60 0 . 00 115582 . 99 36 . 00 44. 00 130 . 00 j 12 . 0 0 . 00 8 .60 0 .00 117354 .71 36 . 00 44 . 00 130 . 00 12 . : 0 0 . 00 8 .60 0 . 00 119103 . 94 36 . 00 44 . 00 130 . 90 12 . - 0 0 . 00 8 .60 0 .00 120831. 54 36 .00 44 .00 130 . 00 I ; 12 . .0 0 .0I0 8 .60 0 .00 122538 .36 36 . 00 44 .00 130 . 00 Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inca * 37 Brookside Rd *. Waterbury, Ct 06708 i 1 Page 3 of 3 H._H i JI VARIABLE COMPUTED Elev. Pressure Elevl. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 21 @ 2 gpm in ft I ft psi ft 1 psi 12 .60 0 . 00 8 . 60 0 .00 124225 .16 36 .00 44.00 130 .00 12.70 0.00 8 .60 0 .00 125892 . 68 36 .00 44 . 00 130 .00 12 . 80 0 . 00 8 . 60 0 .00 127541.58 36 . 00 44 . 00 130 .00 12 . 90 0 . 00 8 . 60 0 .00 129172 .52 36 . 00 44 . 00 130 . 00 13 .00 0 .00 8 .60 0 .00 130786 .11 36 . 00 44 .00 . 130 . 00 13 .10 0 . 00 8 . 60 0 . 00 132382 . 91 36 . 00 44 .00 130 .00 13 .20 0 .00 8 .60 0 .00 133963 .48 36 . 00 44 .00 130 . 00 13 .30 0 .00 8 .60 0 .00 135528 .31 36 . 00 44 .00 130 .00 H 13 .40 0 . 00 8 .60 0 .00 137077 . 90 36 . 00 44 .00 130 . 00 13 .50 0 .00 8 .60 0.00 138612 .71 36 .00 44 .00 130 .00 13 .60 0. 00 8 .60 0 .00 140133 .18 36 .00 44 .00 130 .00 13 .70 0 .00 8 .60 0.00 141639 .73 36 . 00 44 .00 130 .00 13 .80 0 .00 8 . 60 0 .00 143132 .74 36 . 00 44 . 00 130 .00 13 . 90 0 .00 8 .60 0 .00 144612 . 61 36 . 00 44 .00 130 . 00 14.00 0 .00 8 .60 0 .00 146079 . 68 36 . 00 44 . 00 130 .00 14.10 0 .00 8 . 60 0.00 147534 .31 36 .00 44 .00 130 .00 14.20 0 .00 8 .60 0 .00 148976 . 83 36 . 00 44 .00 130 .00 1 , 14.30 0 . 00 8 .60 0.00 150407.54 36 . 00 44 .00 130 .00 14.40 0 . 00 8 . 60 0 .00 151826 . 75 36 . 00 44 .00 130 . 00 1.50 0 .00 8 .60 0 .00 153234 .75 36 .00 44 . 00 130 .00 4 .60 0 . 00 8 .60 0.00 154631. 82 36 . 00 44.00 130 .00 14 .70 0 . 00 8 . 60 0 .00 156018 .21 36 . 00 44 .00 130 . 00 14 . 80 0 . 00 8 .60 0 . 00 157394 .19 36 .00 44 . 00 130 .00 14 . 90 0 . 00 8 .60 0 . 00 158760 . 00 36 . 00 44 . 00 130 .00 15 .00 0 . 00 8 .60 0. 00 160115. 87 36 . 00 44 . 00 130 .00 15.10 0 . 00 8 . 60 0 .00 161462 . 02 36 . 00 44 .00 130 . 00 15.20 0 .00 8 .60 0 . 00 162798 . 69 36 . 00 44 .00 130 . 00 15 .30 0 . 00 8 . 60 0 .00 164126 . 07 36 . 00 44 .00 130 .00 i 15 .40 0 . 00 8 .60 0 .00 165444 .37 36 .00 44.00 130 .00 15.50 0 .00 8 .60 0 .00 166753 .78 36 .00 44 .00 130 .00 15.60 0 .00 8 .60 0 . 00 168054 .49 36 .00 44 .00 130 . 00 15.70 0 . 00 8 .60 0 .00 169346 . 68 36 . 00 44 .00 130 .00 15 .80 0 . 00 8 .60 0 .00 170630 .53 36 .00 44 .00 130 .00 15 . 90 0 . 00 8 . 60 0 . 00 171906 .19 36 . 00 44 . 00 130 . 00 16 .00 0 . 00 8 . 60 0 . 00 173173 . 85 36 . 00 44 .00 130 .00 • 16 .10 0 . 00 8 .60 0 .00 174433 . 65 36 . 00 44 . 00 130 . 00 I 1 1 Open Channel Flow Module, Version 3 .11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 i ' 9/14/98 7 :39 : 15 am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE SWMP, BSN A ROUTED TO SPRINGBROOK CR LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- c-PEAK-> OUTFLOW STORAGE c DESICRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, PRE SWMP A 0.00 0.21 DELTA PSTA 7.60 8 0.00 6984.20 cf 2YR, PRE SWMP A 0.00 2.00 DELTA PSTA 8.63 9 1.64 91244.70 cf 5YR, PRE SWMP A 0.00 2.90 DELTA PSTA 8.66 10 2.86 93500.70 cf 10YR, PRE SWMP A 0.00 4.13 DELTA PSTA 8.69 11 4.10 95776.42 cf 25YR, PRE SWMP A 0.00 5.39 DELTA PSTA 8.71 12 5.37 98119.36 cf 50YR, PRE SWMP A 0.00 5.51 DELTA PSTA 8.71 13 5.49 98353.65 cf 100YR, PRE SWMP A 0.00 6.67 DELTA PSTA 8.74 14 6.63 2 ac-ft II' II I D • File . Input Hydrograph Storage Discharge LPool Proj : SWMP 1eeeeeeeeeeeeeee6eeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeeei' o MATCH INFLOW STO DIS PEAK PEAK OUT 1 ' o . DESCRIPTION PEAK PEAK No.No. STG OUT HYD 0 O WQ, PRE BSN 4-1&4-4 0 . 00 0. 88 4A PRE1&4 9 .22 0 . 88 8 • 2YR, PRE BSN 4-1&4-4 0 : 00 10 . 70 4A PRE1&4 11 . 05 7 . 08 9 5YR, PRE BSN 4-1&4-4 *0 14 .35 4A PRE1&4 11 .46 7 . 87 10 0 10YR,PRE BSN 4-1&4-4 0 . 00 19 . 07 4A PRE1&4 12 . 06 8 . 91 11 0 I 25YR,PRE BSN 4-1&4-4 0 . 00 23 . 90 4A PRE1&4 12 .44 9 .53 12 50YR, PRE BSN 4-1&4-4 0 '. 00 24 .38 4A PRE1&4 12 .49 9 . 59 13 0 100YR, PRE BSN4-1&4-4 0L00 28 . 77 4A PRE1&4 12 . 89 10 .21 14 0° 0 O O 0 O Done< Press any key to exit 0 aeeeeeee6eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee6eeeeeeef- Menu: Perform Level pool computations using input table instructions I I RE. - 40E:\) OP Iv\N T 5V) AC.E WA-cER 6ANAGE. MENT MI ELT 6ASNS ;H-' d y-y R0h'SE0 THR,OV GN M Nit.) RNLI- Sw(aL.F, Z - `(EA& I.‘J i 1 I 9/10/98 11 : 8 :59 am Sverdrup Civil Inc page 1 THE BOEING COMPANY r SURFACE WATER MANAGEMENT PROJECT PRE-DEV BSN 4-1&4-4 ROUTED THRU MAIN TRK STAGE STORAGE TABLE CUSTOM STORAGE ID No. 4A Description: POND4A I 1 STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (f ) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 9.00 0.0000 0.0000 10.80 9487 0.2178 12.60 89682 2.0588 14.40 388057 8.9086 9.10 218.63 0.0050 10.90 10400 0.2388 12.70 97533 2.2391 14.50 414726 9.5208 9.20 437.26 0.0100 11!00 11313 0.2597 12.80 105384 2.4193 14.60 441394 10.133 9.30 655.88 0.0151 ii1110 14439 0.3315 12.90 113236 2.5995 14.70 468063 10.745 9.40 874151 0.0201 11J20 17565 0.4032 13.00 121087 2.7798 14.80 494732 11.357 I 9.50 1093 0.0251 11130 20691 0.4750 13.10 137117 3.1478 14.90 521401 11.970 9.60 1312 0.0301 11.40 23817 0.5468 13.20 153146 3.5158 15.00 548069 12.582 I I 9.70 1530 0.0351 11150 26943 0.6185 13.30 169176 3.8837 15.10 10493262 240.89 9.80 1749 0.0402 11'60 30069 0.6903 13.40 185205 4.2517 15.20 20438456 469.20 I 9.90 1968 0.0452 11170 33195 0.7621 13.50 201235 4.6197 15.30 30383649 697.51 10.00 2186 0.0502 11.80 36322 0.8338 13.60 217264 4.9877 15.40 40328842 925.82 10.10 3099 0.0711 11.90 39448 0.9056 13.70 233294 5.3557 15.50 50274035 1154 10.20 4012 0.0921 12.00 42574 0.9774 13.80 249323 5.7237 15.60 60219228 1382 10.30 4924 0.1130 12i10 50425 1.1576 13.90 265353 6.0917 15.70 70164421 1611 10.40 5837 0.1340 12.20 58276 1.3378 14.00 281382 6.4596 15.80 80109614 1839 10.50 6749 0.1549 121.30 66128 1.5181 14.10 308051 7.0719 15.90 90054807 2067 I 10.60 7662 0.1759 12.40 73979 1.6983 14.20 334719 7.6841 10.70 8575 0.1968 12i50 81830 1.8786 14.30 361388 8.2963 I I 9/10/98 11 : 8 : 54, .am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BSN 4-1&4-4 ROUTED THRU MAIN TRK STAGE DISCHARGE TABLE CUSTOM DISCHARGE ID No. PRE1&4 Description: POND1&4 STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs 9.15 0.0000 10.95 6.8760 12.75 9.9980 14.55 12.446 9.25 1.3950 11.05 7.0795 12.85 10.147 14.65 12.570 9.35 2.0825 11.15 7.2785 12.95 10.295 14.75 12.693 9.45 2.6040 11.25 7.4730 13.05 10.440 14.85 12.815 9.55 3.0465 11.35 7.6630 13.15 10.584 14.95 12.936 9.65 3.4390 11.45 7.8495 13.25 10.726 15.05 13.056 9.75 3.7960 11.55 8.0320 13.35 10.866 15.15 13.175 9.85 4.1265 11.65 8.2110 13.45 11.005 15.25 13.293 9.95 4.4360 11.75 8.3870 13.55 11.143 15.35 13.410 10.05 4.7280 11.85 8.5595 13.65 11.279 15.45 13.526 10.15 5.0050 11.95 8.7290 13.75 11.413 15.55 13.642 10.25 5.2695 12.05 8.8960 13.85 11.547 15.65 13.756 10.35 5.5235 12.15 9.0605 13.95 11.679 15.75 13.870 I 10.45 5.7675 12.25 9.2225 14.05 11.810 15.85 13.984 10.55 6.0030 12.35 9.3820 14.15 11.940 15.95 14.096 10.65 6.2310 12.45 9.5390 14.25 12.068 16.05 14.208 10.75 6.4520 12.55 9.6940 14.35 12.195 16.15 14.263 10.85 6.6670 12.65 9.8470 14.45 12.321 i I I Page 1 of 3 Pressure Pipe Analysis & Design Circular Pipe orksheet Name: Bl&B4 ROUTED escription: BASIN B. SUB-BASIN B1&B4 ROUTED (MAIN TRACK) olve For Discharge iven Constant Data; , Pressure @ 1 0 . 00 Elevation @ 2 9 . 15 2',R -CfkIL`vA-rE1 sealfoC I ooK CP EK, Pi-essure @ 1 0 . 00 Discharge 806 . 63 Diameter 12 . 00 Length 101. 00 Hazen-Williams C 140 . 0000 Varia•le Input Data Minimum Maximum Increment By Elev-tion @ 1 9 . 00 16 . 00 0 . 10 I BASIN y'. DI5c14rtil6E: Ritz-cii..)Cv CkAvg CALCu..P VIo, S Fats 5v(3-- (Msi)5 4--1 -V LI—y Rourrga 74Ko 6H sA N i RAck SwPa.E • pRE— DEveLoPMEN'C SURFPcGE I./A--0k Miscn.)itGE M.E.VT PRcs-Eri I Q -YENE, -TPo.L\J TE1 = cl,kS i Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 1 1 I 1 i 1 Page 2 of 3 VARIABLE COMPUTED i Elev. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2 @ 2 gpm in ft ft psi ft psi 9 . 00 0 . 00 9 .15 0 . 00 -806 .63 12 . 00 101. 00 - 140 . 00 9 . 10 0 . 00 9 . 15 0 . 00 -445 .68 12 . 00 101. 00 140 . 00 9 .20 0 . 00 9 .15 0 . 00 445 .68 12 . 00 101. 00 140 . 00 9.30 0 . 00 9 .15 0 . 00 806 .63 12 . 00 101 . 00 .140 . 00. 9 .40 0 . 00 9 . 15 0 . 00 1062 . 85 12 . 00 101 . 00 140 . 00 9 .50 0 . 00 9 .15 0 . 00 1274 .62 12 . 00 101 . 00 140 . 00 1 , 9 .60 0 . 00 9 . 15 0 . 00 1459 .88 12 . 00 101. 00 140 . 00 H1 9 .70 0 . 00 9 .15 0 . 00 1626 .97 12 . 00 101. 00 140 . 00 9 . 80 0 . 00 9 .15 0 . 00 1780 .56 12 . 00 101 . 00 140 . 00 9 . 90 0 . 00 9 . 15 0 . 00 1923 .61 12 . 00 101 . 00 140 . 00 I 10 . 00 0 . 00 9 . 15 0 . 00 2058 .12 12 . 00 101 . 00 140 . 00 10 . 10 0 . 00 9 . 15 0 . 00 2185 .52 12 . 00 101 . 00 140 . 00 10 .20 0 . 00 9 .15 0 . 00 2306 .89 12 . 00 101 . 00 140 . 00 10 .30 0 . 00 9 . 15 0 . 00 2423 . 04 12 . 00 101. 00 140 . 00 10 .40 0 . 00 9 . 15 0 . 00 2534 .63 12 . 00 101. 00 140 . 00 10 .50 0 . 00 9 .15 0 . 00 2642 .19 12 . 00 101. 00 140 . 00 1 10 . 60 0 . 00 9 . 15 0 . 00 2746 .14 12 . 00 101. 00 140 . 00 10 . 70 0 . 00 9 .15 0 . 00 2846 .84 12 . 00 101 . 00 140 . 00 0 . 80 0 . 00 9 . 15 0 . 00 2944 .59 12 . 00 101. 00 140 . 00 0 . 90 0 . 00 9 . 15 0 . 00 3039 .66 12 . 00 101. 00 140 . 00 11. 00 0 . 00 9 . 15 0 . 00 3132 .25 12 . 00 101 . 00 140 . 00 11.10 0 . 00 9 . 15 0 . 00 3222 .57 12 . 00 101 . 00 140 . 00 11 .20 0 . 00 9 . 15 0 . 00 3310 .78 12 . 00 101 . 00 140 . 00 i 11 .30 0 . 00 9 . 15 0 . 00 3397 . 04 . 12 . 00 101 . 00 140 . 00 11.40 0 . 00 9 . 15 0 . 00 3481 .47 12 . 00 101 . 00 140 . 00 11 . 50 0 . 00 9 .15 0 . 00 3564 . 19 12 . 00 101 . 00 140 . 00 11. 60 0 . 00 9 . 15 0 . 00 3645 .30 12 . 00 101 . 00 140 . 00 11 . 70 0 . 00 9 . 15 0 . 00 3724 . 91 12 . 00 101. 00 140 . 00 11 . 80 0 . 00 9 . 115 0 . 00 3803 .09 12 . 00 101. 00 140 . 00 11 . 90 0 . 00 9 . 15 0 . 00 3879 . 93 12 . 00 101 . 00 140 . 00 12 . 00 0 . 00 9 . 15 0 . 00 3955 .49 12 . 00 101 . 00 140 . 00 12 . 10 0 . 00 9 . 15 0 . 00 4029 .84 12 . 00 101 . 00 140 . 00 12 . 20 0 . 00 9 . 15 0 . 00 4103 . 04 12 . 00 101 . 00 140 . 00 12 . 30 0 . 00 9 . 15 0 . 00 4175 .15 12 . 00 101 . 00 140 . 00 12 .40 0 . 00 9 . 15 0 . 00 4246 .20 12 . 00 101 . 00 140 . 00 12 . 50 0 . 00 9 . 15 0 . 00 4316 .26 12 . 00 101 . 00 140 . 00 12 . 60 0 . 00 9 . 15 0 . 00 4385 .37 12 . 00 101 . 00 140 . 00 12 .70 0 . 00 9 . 15 0 . 00 4453 .56 12 . 00 101 . 00 140 . 00 12 . 80 0 . 00 9 . 15 0 . 00 4520 . 87 12 . 00 101 . 00 140 . 00 12 . 90 0 . 00 9 . 15 0 . 00 4587 .34 12 . 00 101 . 00 140 . 00 Open Channel Flow', Module, Version 3 . 11 (c) Haestad Methods, ;Inc. * 37 Brookside Rd * Waterbury, Ct 06708 I i Page 3 of 3 V IABLE COMPUTED El v. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @1 @1 @2 @2 . gpm in ft f psi ft psi 1 13 . 0 0 . 00 9 . 15 0 . 00 4653 . 00 12 . 00 101. 00 140 . 00 13 . 10 0 . 00 9 .15 0 . 00 4717 . 87 12 . 00 101 . 00 140 . 00 13 .20 0 . 00 9 .15 0 . 00 4782 . 00 12 . 00 101. 00 140 .00 13 . 0 0 . 00 9 . 15 0 . 00 4845 .40 12 . 00 101. 00 140 . 00 13 . 40 0 . 00 9 .15 0 . 00 4908 .11 12 . 00 101 . 00 140 . 00 13 . %0 0 . 00 9 . 15 0 . 00 4970 . 13 12 . 00 101 . 00 140 . 00 13 . 1.0 0 . 00 9 .15 0 . 00 5031 . 51 12 . 00 101 . 00 140 . 00 13 . 70 0 . 09 9 .15 0 . 00 5092 . 25 12 . 00 101. 00 140 . 00 13 . :0 0 . 00 9 . 15 0 . 00 5152 .39 12 . 00 101 . 00 140 . 00 13 . "0 0 . 00 . 9 . 15 0 . 00 5211. 93 12 . 00 101. 00 140 . 00 14 . )0 0 . 00 9 . 15 0 . 00 5270 . 90 12 . 00. 101 . 00 140 . 00 14 . 0 0 . 00 9 .15 0 . 00 5329 .31 12 . 00 101. 00 140 . 00 14 . 0 0 . 00 9 .15 0 . 00 5387 . 18 12 . 00 101. 00 140 . 00 14 . : 0 0 . 00 9 . 15 0 . 00 5444 .52 12 . 00 101 . 00 140 . 00 14 . 40 0 . 00 9 .15 0 . 00 5501 . 36 12 . 00 101. 00 140 . 00 14 . .0 0 . 00 9 . 15 0 . 00 5557 . 70 12 . 00 .101 . 00 140 . 00 14 . .0 0 . 00 9 . 15 0 . 00 5613 .55 12 . 00 101. 00 140 . 00 14 . 0 0 . 0 0 9 .15 0 . 00 5668 . 94 12 . 00 101 . 00 140 . 00 4 . :0 0 . 00 9 . 15 0 . 00 5723 . 87 12 . 00 101 . 00 140 . 00 4 . s0 0 . 00 9 . 15 0 . 00 5778 .36 12 . 00 101. 00 140 . 00 15 . .0 0 . 00 9 . 15 0 . 00 5832 .41 12 . 00 101 . 00 140 . 00 15 . 10 0 . 00 9 . 15 0 . 00 5886 . 04 12 . 00 101. 00 140 . 00 , 15 .'0 0 . 00 9 .15 ' 0 . 00 5939 .25 12 . 00 101. 00 140 . 00 15 . 0 0 . 00 9 . 15 . 0 . 00 5992 . 06 12 . 00 101 . 00 140 . 00 15 . 40 0 . 00 9 . 15 0 . 00 6044 .48 12 . 00 101 . 00 140 . 00 15 . 50 0 . 00 9 .15 ' 0 . 00 6096 . 52 12 . 00 101 . 00 140 . 00 15 . 60 0 . 00 9 . 15 0 . 00 6148 . 17 12 . 00 101. 00 140 . 00 15 . 70 0 . 00 9 . 15 ; 0 . 00 6199 .46 12 . 00 101. 00 140 . 00 15 . 80 0 . 00 9 . 15 0 . 00 6250 .40 12 . 00 101 . 00 140 . 00 15 . 90 0 . 00 9 . 15 , 0 . 00 6300 . 98 12 . 00 101 . 00 140 . 00 16 . 00 0 . 00 9 .15 0 . 00 6351 .21 12 . 00 101. 00 140 . 00 , 16 . 10 0 . i0 9 . 15 0 . 00 6401 . 12 12 . 00 101 . 00 140 . 00 Open Clannel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 9/10/98 11 : 9 : 0 am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BSN 4-1&4 '-4 ROUTED THRU MAIN TRK LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- c-STAGE> id (cfs) VOL (cf) WQ, PRE BSN 4-1&4-4 0.00 0.88 4A PRE1&4 9.22 8 0.88 470.09 cf I 2YR, PRE BSN 4-1&4-4 0.00 10.70 4A PRE1&4 11.05 9 7.08 12951.22 cf 5YR, PRE BSN 4-1&4-4 0.00 14.35 4A PRE1&4 11.46 10 7.87 25775.48 cf 10YR,PRE BSN 4-1&4-4 0.00 19.07 4A PRE1&4 12.06 11 8.91 47010.13 cf 25YR,PRE BSN 4-1&4-4 0.00 23.90 4A PRE1&4 12.44 12 9.53 77283.00 cf i 50YR,PRE BSN 4-1&4-4 0.00 24.38 4A PRE1&4 12.49 13 9.59 80662.15 cf 100YR,PRE BSN4-1&4-4 0.00 28.77 4A PRE1&4 12.89 14 10.21 3 ac-ft D • ile Input Hydrogaph Storage Discharge LPool Proj : SWMP eeee 'eeeeeeeeeeeeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeee; MATCH INFLOW STO DIS PEAK PEAK OUT o DESCRIPTION PEAK ! PEAK No.No. STG OUT . HYD o IQ, P•E BASIN 4H 0 . 00 1 . 05 PONDB POND"B" 9 . 18 0 .40 1 2YR, 'RE BASIN 4-5 0 . 00 4 .37 PONDB POND"B" 9 .53 1 . 93 2 RE BASIN 4-5 0 . 00 5 .40 PONDB POND"B" 9 . 66 2 .23 3 L0R, PRE BASIN 4-5 0 . 00 . 6 . 68 PONDB POND"B" - 9 . 83 2 . 59 4 25YR, PRE BASIN 4-5 0 . 00 7 . 96 PONDB POND"B" 10 . 01 3 . 09 5 0 50YR, PRE BASIN 4-5 0 . 00 8 . 09 PONDB POND"B" 10 . 03 3 . 16 6 0 00YR, PRE BASIN 4-5 0 . 00 9 .25 PONDB POND"B" 10 . 16 3 . 70 7 0 O 0 0 O Done< Press any key to exit 0 eeee=eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef I - 1 gnu: Perform Level pool computations using input table instructions I f RE - OE v;E LoP n EN 1 SV(kfokce tiJ/'t•tER PiftnJA(.ENIEN l PR.ciSECT BAsiN Lt-5 Roar-rao Tn-muo(caN #'oNQ "a " a . FINK. rz = 61.15 9/10/98 11 :19 :44 am Sverdrup Civil Inc page 1 -I THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRELDEV BASIN 4-5', ROUTED THRU POND "B" STAGE STORAGE TABLE CUSTOM STORAGE ID No. PONDB Description: POND "B" STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (;ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 9.00 0.0000 0.0000 10.60 38566 0.8853 12.20 83763 1.9229 13.80 135034 3.0999 9.10 2297 0.0527 10.70 41165 0.9450 12.30 86850 1.9938 13.90 138355 3.1762 9.20 4594 0.1055 10.80 43764 1.0047 12.40 89938 2.0647 14.00 141676 3.2524 9.30 6891 0.1582 10.90 46363 1.0643 12.50 93026 2.1356 14.10 145238 3.3342 9.40 9188 0.2109 11.00 48962 1.1240 12.60 96114 2.2065 14.20 148801 3.4160 9.50 11486 0.2637 11.10 51825 1.1897 12.70 99202 2.2774 14.30 152363 3.4978 9.60 13783 0.3164 11.20 54687 1.2554 12.80 102289 2.3482 14.40 155925 3.5796 9.70 16080 0.3691 11.30 57550 1.3212 12.90 105377 2.4191 14.50 159488 3.6613 9.80 18377 0.4219 11.40 60412 1.3869 13.00 108465 2.4900 14.60 163050 3.7431 9.90 20674 0.4746 11.50 63275 1.4526 13.10 111786 2.5663 14.70 166612 3.8249 10.00 22971 0.5273 11.60 66137 1.5183 13.20 115107 2.6425 14.80 170174 3.9067 10.10 25570 0.5870 11.70 69000 1.5840 13.30 118428 2.7187 14.90 173737 3.9884 10.20 28169 0.6467 11.80 71862 1.6497 13.40 121749 2.7950 15.00 177299 4.0702 10.30 30768 0.7063 11.90 74725 1.7154 13.50 125071 2.8712 I 10.40 33367 0.7660 12.00 77587 1.7812 13.60 128392 2.9475 10.50 35967 0.8257 12.10 80675 1.8520 13.70 131713 3.0237 I I I I I 9/10/98 . 11 :19 :44iam Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-5, ROUTED THRU POND "B" STAGE DISCHARGE TABLE CUSTOM DISCHARGE ID No. POND"B" Description: PONDB! I I STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfi ft) ---cfs ft) ---cfs ft) ---cfs 9.15 0.0000 10.45 4.2750 11.75 6.0465 13.05 22.903 I 9.25 0.9585 10'.55 4.4365 11.85 6.1620 13.15 23.719 9.35 1.3920 101.65 4.5925 11.95 6.2750 13.25 24.504 9.45 1.7125 10,.75 4.7430 12.05 6.6940 13.35 25.260 9.55 1.9805 101.85 4.8890 12.15 7.6740 13.45 25.990 9.65 2.2L60 101.95 5.0310 12.25 9.0735 13.55 26.698 9.75 2.4285 11.05 5.1690 12.35 10.772 13.65 27.385 9.85 2.6235 11.15 5.3030 12.45 12.719 13.75 28.054 9.95 2.805018i050 11.25 5.4340 12.55 14.884 13.85 28.704 10.05 3.2740 11'.35 5.5620 12.65 17.246 13.95 29.339 10.15 3.7490 111.45 5.6870 12.75 19.584 14.05 29.653 10.25 3.9320 11.55 5.8095 12.85 21.155 10.35 4.11070 11L65 5.9290 12.95 22.050 I I j I I I 1-- The Boeing Company Surface Water Management Project Pond"B"Control Structure with Springbrook Creek 2-Year Tailwater EL 9.15 Orifice 1,dia= 8.75 in. at EL 5.75(structure outlet pipe I.E.=9.00) Orifice 2,dia= 6.25 in. at EL 9.50(on 6°elbow) Orifice 3,dia= 4.75 in. at EL 9.80(on 6'elbow) Riser,dia= 24.00 in. at EL 12.00 Stage Area Area Area Area Tailwater Dif.Head Orifice Flowrate Flowrate Flowrate Flowrate- Total ft)(1) of Orifice 1 of Orifice 2 of Orifice 3 of Riser Elevation at Orifice Coefficient, Orifice 1 Orifice 2 Orifice 3 Riser Flowrate ft2)ft2)tt2)lib(It)C (cfs)( 2) ( cfs)( 2) (cfs)(2) (cfs)(3) (cfs)(1) 9.15 0.42 0.21 0.12 3.14 9.15 0.00 0.62 0.00 0.00 0.00 0.00 0.00 9.20 0.42 0.21 0.12 0.79 9.15 0.05 . 0.62 0.46 0.24 0.00 • 0.00 0.70 9.3 0.42 0.21 0.12 0.79 9.15 0.15 0.62 0.80 0.41 0.00 0.00 1.22 9.4 0.42 0.21 0.12 0.79 9.15 0.25 0.62 1.04 0.53 0.00 0.00 1.57 9.5 0.42 0.21 0.12 0.79 9.15 0.35 0.62 1.23 0.63 0.00 0.00 1.86 9.6 0.42 0.21 0.12 0.79 9.15 0.45 0.62 1.39 0.71 0.00 0.00 2.10 9.7 0.42 0.21 0.12 0.79 9.15 0.55 0.62 1.54 0.79 0.00 0.00 2.33 9.8 0.42 0.21 0.12 0.79 9.15 0.65 0.62 1.68 0.85 0.00 0.00 2.53 9.9 0.42 0.21 0.12 0.79 9.15 0.75 0.62 1.80 0.92 0.00 0.00 2.72 I 10.0 0.42 0.21 0.12 0.79 9.15 0.85 0.62 1.92 0.98 0.00 0.00 2.89 10.1 0.42 0.21 0.12 0.79 9.15 0.95 0.62 2.03 1.03 0.60 0.00 3.66 10.2 0.42 0.21 0.12 0.79 9.15 1.05 0.62 2.13 1.09 0.63 0.00 3.84 10.3 0.42 0.21 0.12 0.79 9.15 1.15 0.62 2.23 1.14 0.66 0.00 4.02 10.4 0.42 0.21 0.12 0.79 9.15 125 0.62 2.32 1.19 0.68 0.00 4.19 10.5 0.42 0.21 0.12 0.79 9.15 1.35 0.62 2.41 1.23 0.71 0.00 4.36 10.6 0.42 0.21 0.12 0.79 9.15 1.45 0.62 2.50 1.28 0.74 0.00 4.52 10.7 0.42 0.21 0.12 0.79 9.15 1.55 0.62 2.59 1.32 0.76 0.00 4.67 10.8 0.42 0.21 0112 0.79 9.15 1.65 0.62 2.67 1.36 0.79 0.00 4.82 10.9 0.42 0.21 0112 0.79 9.15 1.75 0.62 2.75 1.40 0.81 0.00 4.96 11.0 0.42 0.21 0:12 0.79 9.15 1.85 0.62 2.83 1.44 0.83 0.00 5.10 11.1 0.42 0.21 0112 0.79 9.15 1.95 0.62 2.90 1.48 0.86 0.00 5.24 11.2 0.42 0.21 0:12 0.79 9.15 2.05 0.62 2.97 1.52 0.88 0.00 5.37 11.3 0.42 0.21 0:12 0.79 9.15 2.15 0.62 3.05 1.55 0.90 0.00 5.50 11.4 0.42 0.21 0112 0.79 9.15 2.25 0.62 3.12 1.59 0.92 0.00 5.62 11.5 0.42 0.21 0112 0.79 9.15 2.35 0.62 3.19 1.63 0.94 0.00 5.75 11.6 0.42 0.21 0:12 0.79 9.15 2.45 0.62 3.25 1.66 0.96 0.00 5.87 11.7 0.42 0.21 0.12 0.79 9.15 2.55 0.62 3.32 1.69 0.98 0.00 5.99 11.8 0.42 0.21 0.12 0.79 9.15 2.65 0.62 3.38 1.73 1.00 0.00 6.10 I 11.9 0.42 0.21 0:12 0.79 9.15 2.75 0.62 3.45 1.76 1.02 0.00 6.22 12.0 0.42 0.21 0:12 0.79 9.15 2.85 0.62 3.51 1.79 1.03 0.00 6.33 12.1 0.42 0.21 0112 0.79 9.15 2.95 0.62 3.57 1.82 1.05 0.62 7.06 12.2 0.42 0.21 0.12 0.79 9.15 3.05 0.62 3.63 1.85 1.07 1.74 8.29 12.3 0.42 0.21 0:12 0.79 9.15 3.15 0.62 3.69 1.88 1.09 320 9.86 12.4 0.42 0.21 0:12 0.79 9.15 3.25 0.62 3.75 1.91 1.10 4.93 11.69 12.5 0.42 0.21 0:12 0.79 9.15 3.35 0.62 3.80 1.94 1.12 6.89 13.75 12.6 0.42 0.21 0.12 0.79 9.15 3.45 0.62 3.86 1.97 1.14 9.05 16.02 12.7 0.42 0.21 0.12 0.79 9.15 3.55 0.62 3.91 2.00 1.15 11.41 18.47 12.8 0.42 0.21 0:12 0.79 9.15 3.65 0.62 3.97 2.03 1.17 13.53 20.70 1 12.9 0.42 0.21 0!12 0.79 9.15 3.75 0.62 4.02 2.05 1.19 14.35 21.61 13.0 0.42 0.21 0.12 0.79 9.15 3.85 0.62 4.08 2.08 1.20 15.13 22.49 13.1 0.42 0.21 0:12 0.79 9.15 3.95 0.62 4.13 2.11 1.22 15.87 23.32 13.2 0.42 0.21 0.12 0.79 9.15 4.05 0.62 4.18 2.13 1.23 16.57 24.12 13.3 0.42 0.21 0:12 0.79 9.15 4.15 0.62 4.23 2.16 1.25 17.25 24.89 13.4 0.42 0.21 0:12 0.79 9.15 4.25 0.62 4.28 2.19 1.26 17.90 25.63 13.5 0.42 0.21 0:12 0.79 9.15 4.35 0.62 4.33 2.21 1.28 18.53 26.35 13.6 0.42 0.21 0.12 0.79 9.15 4.45 0.62 4.38 2.24 1.29 19.14 27.05 13.7 0.42 0.21 0.12 0.79 9.15 4.55 0.62 4.43 2.26 1.31 19.72 27.72 13.8 0.42 0.21 0.12 0.79 9.15 4.65 0.62 4.48 2.29 1.32 20.30 28.38 13.9 0.42 0.21 0.12 0.79 9.15 4.75 0.62 4.53 2.31 1.33 20.85 29.03 14.0 0.42 0.21 0.12 0.79 9.15 4.85 0.62 4.58 2.33 1.35 21.39 29.65 Notes: 1) Pond"B"cannot discharge flow below EL 9.0 due to design elevation of structure A22. Above EL 14.5,flow leaves Pond"B'via emergency overflow spillway. 2) Q=(C)(Area)(29H0112 3) Q=9.739(D)(H)3/2,wm`Fbw Q=3.782(D2)(H)1/2.Orifice Flow Flow transitions from weir to orifice flow at 0.80 feet of head. 013E193\2220\engr Kbcalc19.xis[2-Year Tailwater] I 1 9/10/98 11 :19 :451am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-5, ROUTED THRU POND "B" LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, PRE BASIN 4-5 0.00 1.05 PONDS POND"B" 9.18 1 0.40 4220.08 cf 2YR, PRE BASIN 4-5 0.00 4.37 PONDB POND"B" 9.53 2 1.93 12252.94 cf 5YR, PRE BASIN 4-5 0.00 5.40 PONDS POND"B" 9.66 3 2.23 15174.64 cf 10YR, PRE BASIN 4-5 0.00 6.68 PONDB POND"B" 9.83 4 2.59 19155.36 cf 25YR, PRE BASIN 4-5 0.00 7.96 PONDB POND"B" 10.01 5 3.09 23245.32 cf 50YR, PRE BASIN 4-5 0.00 8.09 PONDB POND"B" 10.03 6 3.16 23626.45 cf 100YR, PRE BASIN 4-5 0.00 9.25 PONDS POND"B" 10.16 7 3.70 27098.40 cf I i I h File Input Hydrograph Storage Discharge LPool Proj : SWMP Ieeeeeeeeeeeeeeeeeeeeeeee'eeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeeei o MATCH INFLOW STO DIS PEAK PEAK OUT DESCRIPTION PEAK PEAK No.No. STG OUT HYD 0 O 0, WQ, PRE BASIN 4 0 . 00 1 .24 P1&P4&P5 P1&P4&P5 9 . 17 1. 06 8 °, 2YR, PRE BASIN 4 Oi. 00 9 . 00 P1&P4&P5 P1&P4&P5 9 . 78 8 .31 9 0 5YR, PRE BASIN 4 0 . 00 10 . 03 P1&P4&P5 P1&P4&P5 9 . 95 9 .48 10 ° 10YR, PRE BASIN 4 0.. 00 11 .39 Pl&P4&P5 P1&P4&P5 10 . 16 10 . 76 11 °, 25YR, PRE BASIN 4 OLOO 12 . 29 Pl&P4&P5 P1&P4&P5 10 . 32 11. 65 12 ° 50YR, PRE BASIN 4 0 . 00 12 .40 P1&P4&P5 Pl&P4&P5 10 . 34 11 . 74 13 ° 100YR, PRE BASIN 4 0 . 00 13 .37 P1&P4&P5 P1&P4&P5 10 . 50 12 . 55 14 ° O o 0 O o 0 O Done< Press any key to exit 0 aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef Menu: Perform Level pool computations using input table instructions Re _ OEVEL.oc MEN j svRFA(.e. bJASE(k t4p,n1A(°stiaikrT 4Ro ec.11 gfas)rvs 9-1 y-4 d 9 ..5 Rov GD ;o PRAc.1 TR.A C. W P( ER = 9.15 9/10/98 11 :34 :56 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-1, 4-4, & 4-5 ROUTED STAGE STORAGE TABLE CUS TOM STORAGE ID No. Pl&P4&P5 Description: 24PI;PE STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf-f-- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf:-- --Ac-Ft- (ft) ---cf--- --Ac-Ft- I I 9.00 0.0000 0.0000 101.50 42716 0.9806 12.00 120161 2.7585 13.50 326305 7.4909 9.10 2516 0.0578 10.60 46228 1.0612 12.10 131100 3.0097 13.60 345656 7.9352 9.20 5032 0.1155 10I.70 49740 1.1419 12.20 142039 3.2608 13.70 365006 8.3794 I 9.30 7547 0.1733 10.80 53251 1.2225 12.30 152979 3.5119 13.80 384357 8.8236 9.40 , 10063 0.2310 10.90 56763 1.3031 12.40 163918 3.7630 13.90 403708 9.2679 9.50 12579 0.2888 11,.00 60275 1.3837 12.50 174857 4.0142 14.00 423058 9.7121 9.60 15!095 0.3465 111.10 66263 1.5212 12.60 185796 4.2653 14.10 453289 10.406 9.70 17610 0.4043 11.20 72252 1.6587 12.70 196735 4.5164 14.20 483520 11.100 9.80 20126 0.4620 11.30 78241 1.7962 12.80 207674 4.7675 14.30 513751 11.794 9.90 22642 0.5198 111.40 84229 1.9336 12.90 218613 5.0187 14.40 543982 12.488 10.00 251158 0.5775 111.50 90218 2.0711 13.00 229552 5.2698 14.50 574214 13.182 10.10 28669 0.6582 111.60 96207 2.2086 13.10 248903 5.7140 14.60 604445 13.876 10.20 32181 0.7388 11.70 102195 2.3461 13.20 268253 6.1582 14.70 634676 14.570 10.30 35693 0.8194 11.80 108184 2.4836 13.30 287604 6.6025 14.80 664907 15.264 10.40 39204 0.9000 11.90 114173 2.6210 13.40 306955 7.0467 14.90 695138 15.958 I I I I 1 I I I 9/10/98 11 :34 :56 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-1:,4-4, & 4-5 ROUTED STAGE DISCHARGE TABLE II CUSTOM DISCHARGE ID No. Pl&P4&P5 Description: PND1&4&B 1 1 STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs I 9.15 0.0000 10.95 14.690 12.75 21.365 14.55 26.595 9.25 2.9800 11.05 15.125 12.85 21.685 14.65 26.860 9.35 4.4500 11.15 15.550 12.95 21.995 14.75 27.120 9.45 5.5650 11.25 15.965 13.05 22.305 14.85 27.380 9.55 6.5100 11.35 16.375 13.15 22.615 14.95 27.640 9.65 7.3500 11.45 16.775 13.25 22.920 15.05 27.900 9.75 8.1150 11.55 17.165 13.35 23.220 15.15 28.155 9.85 8.8200 11.65 17.550 13.45 23.515 15.25 28.405 9.95 9.4800 11.75 17.925 13.55 23.810 15.35 28.655 10.05 10.105 11.85 18.290 13.65 24.105 15.45 28.905 10.15 10.695 11.95 18.650 13.75 24.390 15.55 29.150 10.25 11.260 12.05 19.010 13.85 24.675 15.65 29.395 10.35 11.805 12.15 19.365 13.95 24.960 15.75 29.640 10.45 12.325 12.25 19.710 14.05 25.235 15.85 29.880 10.55 12.830 12.35 20.050 14.15 25.510 15.95 30.120 10.65 13.315 12.45 20.385 14.25 25.785 16.05 30.360 10.75 13.785 12.55 20.715 14.35 26.055 16.15 30.480 1 10.85 14.245 12.65 21.040 14.45 26.325 I I--1 I Page 1 of 3 Pressure Pipe Analysis & Design Circular Pipe orksheet Name: B1&B4&B2520 Description: BASIN B, SUB-BASIN B1 & B4 & B2520 ROUTED solve For Discharge iven Constant Data; Pressure @ 0 . 00 Elevation @ 2 9 . 15 k— 2%1R TAIL JATCR h'[ 5MA) RoDY. CAME S pressure @ 1 0 . 00 Discharge 1723 . 68 Diameter 24 . 00 Length 724 . 00 Hazen-Williams C 140 . 0000 Varia.le Input Data Minimum Maximum Increment By Elev-tion @ 1 9 . 00 16 . 00 0 . 10 BASIN y DISOHaI.GE R,v ito 6 CvRvE CALCv LA-Ti 6/ J5 PoA 5ve ..8ASuNS t _1 Jut-9 4L .5 Rov'CE0 --Ru i Dy" SccM' ib -CH E vfLptcZ ic.E TR.ALY, PRE— Oev G'L oPMl iG&I 5u0.FkcE wfONM. NANJAGE P'1,E, C PLO j e c.j Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Page 2 of 3 I VARIABLE COMPUTED Elev. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C I , @ 1 @ 1 @ 2 @ 2 gpm in ft ft psi ft : psi 9 . 00 0 . 00 9 . 15 0 . 00 -1723 . 68 24 . 00 724 . 00 140 . 00 9 . 10 0 . 00 9 . 15 0 . 00 -952 .38 24 . 00 724 . 00 140 . 00 9 . 20 0 . 00 9 . 15 0 . 00 952 . 38 24 . 00 724 . 00 140 . 00 9 .30 0 . 00 9 .15 0 . 00 1723 . 68 24 . 00 724 . 00 140 . 00 9 .40 0 . 00 9 . 15 0 . 00 2271 .20 ' 24 . 00 724 . 00 140 . 00 9 . 50 0 . 00 9 . 15 0 . 00 2723 .73 24 . 00 724 . 00 140 . 00 9 . 60 0 . 00 9 . 15 0 . 00 3119 . 62 24 . 00 724 . 00 140 . 00 9 . 70 0 . 00 9 . 15 0 . 00 3476 . 67 24 . 00 724 . 00 140 . 00 9 . 80 0 . 00 9 . 15 0 . 00 3804 . 88 24 . 00 724 . 00 140 . 00 9 . 90 0 . 00 9 . 15 0 . 00 4110 .56 24 . 00 724 . 00 140 . 00 10 . 00 0 . 00 9 . 15 0 . 00 4397. 98 24 . 00 724 . 00 140 . 00 10 . 10 0 . 00 9 .15 0 . 00 4670 .23 24 . 00 724 . 00 140 . 00 10 .20 0 . 00 9 . 15 0 . 00 4929 . 58 24 . 00 724 . 00 140 . 00 I 10 .30 0 . 00 9 . 15 0 . 00 5177 . 79 24 . 00 724 . 00 140 . 00 10 .40 0 . 00 9 . 15 0 . 00 5416 .25 24 . 00 724 . 00 140 . 00 10 . 50 0 . 00 9 . 15 0 . 00 5646 . 09 24 . 00 724 . 00 140 . 00 10 . 60 0 . 00 9 . 15 0 . 00 5868 . 22 24 . 00 724 . 00 140 . 00 10 . 70 0 . 00 9 . 15 0 . 00 6083 .40 24 . 00 724 . 00 140 . 00 0 . 80 0 . 00 9 . 15 0 . 00 6292 . 29 24 . 00 724 . 00 140 . 00 0 . 90 0 . 00 9 . 15 0 . 00 6495 .43 24 . 00 724 . 00 140 . 00 11 . 00 0 . 00 9 . 15 0 . 00 6693 .30 24 . 00 724 . 00 140 . 00 11 . 10 0 . 00 9 . 15 0 . 00 6886 .30 24 . 00 724 . 00 140 . 00 11 . 20 0 . 00 9 . 15 0 . 00 7074 . 81 24 . 00 724 . 00 140. 00 11 . 30 0 . 00 9 . 15 0 . 00 7259 . 12 24 . 00 724 . 00 140 . 00 11 .40 0 . 00 9 . 15 0 . 00 7439 . 54 24 . 00 724 . 00 140 . 00 11 . 50 0 . 00 9 . 15 0 . 00 7616 . 30 24 . 00 724 . 00 140 . 00 11 . 60 0 . 00 9 . 15 0 . 00 7789 . 64 24 . 00 724 . 00 140 . 00 11 . 70 0 . 00 9 . 15 , 0 . 00 7959 . 75 24 . 00 724 . 00 140 . 00 11 . 80 0 . 00 9 . 15 0 . 00 8126 . 81 24 . 00 724 . 00 140 . 00 11 . 90 0 . 00 9 . 15 0 . 00 8291 . 00 24 . 00 724 . 00 140 . 00 1 12 . 00 0 . 00 9 . 15 0 . 00 8452 .47 24 . 00 724 . 00 140 . 00 12 . 10 0 . 00 9 . 15 0 . 00 8611 .35 24 . 00 724 . 00 140 . 00 12 . 20 0 . 00 9 . 15 0 . 00 8767 . 77 24 . 00 724 . 00 140 . 00 12 . 30 0 . 00 9 . 15 0 . 00 8921 . 86 24 . 00 724 . 00 140 . 00 12 .40 0 . 00 9 . 15 0 . 00 9073 .70 24 . 00 724 . 00 140 . 00 12 . 50 0 . 00 9 . 15 0 . 00 9223 .41 24 . 00 724 . 00 140 . 00 12 . 60 0 . 00 9 . 15 0 . 00 9371 . 08 24 . 00 724 . 00 140 . 00 12 . 70 0 . 00 9 . 15 0 . 00 9516 . 80 24 . 00 724 . 00 140 . 00 I , 12 . 80 0 . 00 9 . 15 0 . 00 9660 .63 24 . 00 724 . 00 140 . 00 12 . 90 0 . 00 9 . 15 0 . 00 9802 .67 24 . 00 724 . 00 140 . 00 Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 Page 3 of 3 i V IABLE COMPUTED E1 v. Pressure Elev.i Pressure Discharge Diameter Length Hazen-W C @ 1 @1 @ 2 @ 2 gpm in ft fl psi ft psi 13 . 00 0 . 00 9 . 15 0 . 00 9942 . 97 24 . 00 724 . 00 140 . 00 1310 0 . 00 9 . 15 0 . 00 10081 . 61 24 . 00 724 . 00 140 . 001 13 . 0 0 . 00 9 .15 0 . 00 10218 . 64 24 . 00 724 . 00 140 . 001 13 .30 0 . 00 9 . 15 0 . 00 10354 . 13 24 . 00 724 . 00 140 . 001 13 .0 0 . 00 9 . 15 0 . 00 10488 . 12 24 . 00 724 . 00 140 . 09 13 . 0 0 . 09 9 .15 0 . 00 10620 . 66 24 . 00 724 . 00 140 . 0011 13 . 0 0 . 00 9 .15 0 . 00 10751 . 82 24 . 00 724 . 00 140 . 00 13 . 0 0 . 00 9 . 15 0 . 00 10881. 62 24 . 00 724 . 00 140 . 00 13 . 0 0 . 00 9 . 15 0 . 00 11010 . 12 24 . 00 724 . 00 140 . 00 130 0 . 00 9 . 15 0 . 00 11137 .35 24 . 00 724 . 00 140 . 00 14 . 00 0 . 00 9 .15 0 . 00 11263 .36 24 . 00 724 . 00 140 . 00 14 . 10 0 . 00 9 .15 0 . 00 11388 . 18 24 . 00 724 . 00 140 . 00 14 . 0 0 . 00 9 . 15 0 . 00 11511. 84 24 . 00 724 . 00 140 . 00 14 .30 0 . 00 9 . 15 0 . 00 11634 . 38 24 . 00 724 . 00 140 . 00 14 . 0 0 . 00 9 . 15 0 . 00 11755 . 84 24 . 00 724 . 00 140 . 00 14 . 0 0 . 00 9 . 15 0 . 00 11876 . 23 24 . 00 724 . 00 140 . 00 14 . 0 0 . 0 0 9 . 15 0 . 00 11995 . 59 24 . 00 724 . 00 140 . 00 14 . 0 0 . 00 9 .15 0 . 00 12113 . 95 24 . 00 724 . 00 140 . 00 4 . 80 0 . 00 9 . 15 0 . 00 12231 . 33 24 . 00 724 . 00 140 . 00 4 . 90 0 . 00 9 . 15 0 . 00 12347 . 76 24 . 00 724 . 00 140 . 00 15 . 00 0 . 00 9 . 15 0 . 00 12463 .26 24 . 00 724 . 00 140 . 00 15 . 10 0 . 00 9 . 15 0 . 00 12577 . 86 24 . 00 724 . 00 140 . 00 15 .20 0 . 00 9 . 15 0 . 00 12691 . 57 24 . 00 724 . 00 140 . 00 15 .30 0 . 00 9 . 15 0 . 00 12804 .42 24 . 00 724 . 00 140 . 00 15 .40 0 . 00 9 . 15 0 . 00 12916 .44 24 . 00 724 . 00 140 . 00 15 . 50 0 . 00 9 . 15 0 . 00 13027 . 63 24 . 00 724 . 00 140 . 00 15 . 60 0 . 00 9 . 15 0 . 00 13138 . 01 24 . 00 724 . 00 140 . 00 15 . 70 0 . 00 9 . 15 0 . 00 13247 . 62 24 . 00 724 . 00 140 . 00 15 . 80 0 . 00 9 . 15 0 . 00 13356 .45 24 . 00 724 . 00 140 . 00 15 . 90 0 . 00 9 . 15 0 . 00 13464 . 54 24 . 00 724 . 00 140 . 00 16 . 00 0 . 00 9 . 15 0 . 00 13571 . 89 24 . 00 724 . 00 140 . 00 16 . 10 0 . 00 9 . 15 0 . 00 13678 . 52 24 . 00 724 . 00 140 . 00 I 1 II i Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, IInc. * 37 Brookside Rd * Waterbury, Ct 06708 i r 9/10/98 . 11 :34 :57 am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-1, 4-4, & 4-5 ROUTED LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, PRE BASIN 4 0.00 1.24 P1&P4&P5 P1&P4&P5 9.17 8 1.06 4301.92 cf 2YR, PRE BASIN 4 0.00 9.00 P1&P4&P5 P1&P4&P5 9.78 9 8.31 19599.96 cf 5YR, PRE BASIN 4 0.00 10.03 P1&P4&P5 P1&P4&P5 9.95 10 9.48 23921.97 cf 10YR, PRE BASIN 4 0.00 11.39 P1&P4&P5 P1&P4&P5 10.16 11 10.76 30873.53 cf 25YR, PRE BASIN 4 0.00 12.29 Pl&P4&P5 P1&P4&P5 10.32 12 11.65 36478.54 cf SOYR, PRE BASIN 4 0.00 12.40 Pl&P4&P5 P1&P4&P5 10.34 13 11.74 37066.44 cf 100YR, PRE BASIN 4 0.00 13.37 Pl&P4&P5 P1&P4&P5 10.50 14 12.55 42542.46 cf II II D ile Input Hydrograph Storage Discharge LPool Proj : SWMP eeee=eeeeeeeeeeeeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeee; MATCH INFLOW STO DIS PEAK PEAK OUT o DISCRIPTION PEAK PEAK No.No. STG OUT HYD 0 1 0 ad, P'E BASIN 4-610 . 00 0 .26 PONDC COMB02 10 . 00 0 . 26 1 0 2YR, PRE BASIN 4-6 0 . 00 1.26 PONDC COMB02 11. 31 0 . 38 2 0 SYR, PRE BASIN 4-6 0 . 00 1. 64 PONDC COMB02 11 .47 0 . 52 3 0 L YR, PRE BASIN 4-6 0 .100 2 . 12 PONDC COMB02 11 . 66 0 . 68 4 0 25YR, PRE BASIN 4-6 0 . 00 2 . 62 PONDC COMB02 11 . 88 0 . 87 5 0 50YR, PRE BASIN 4-6 040 2 . 67 PONDC COMB02 11 . 90 0 . 90 6 100Y* , PRE BASIN 4-6 0 . 00 3 . 13 PONDC COMB02 12 . 10 1. 04 7 0 0 o 1 0 I 0 1 0 O _ f Don!e< Press any key to exit 0 4Qeee=eeeeeeeeeeeeeeeeeeee'eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef enu: Perform Level pool computations using input table instructions PRE _ OEveLo4ME01' 5L lLr ac-v. wA1 SK V%FvNA GE MS nJT PR oSG.:Ci r+Li, SirJ —(1,od-rap TH•RoJC,+4 Pon o dA CFRk bA«.WA'(FiC = 9.15 9/10/98 11 :45 :18 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-6, ROUTED THROUGH POND"C" STAGE STORAGE TABLE CUSTOM STORAGE ID No. PONDC Description: POND, "C" STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 11.00 0.0000 0.0000 11.80 5293 0.1215 12.60 11559 0.2654 13.40 18761 0.4307 11.10 629.19 0.0144 11.90 6009 0.1379 12.70 12424 0.2852 13.50 19697 0.4522 11.20 1258 0.0289 12.00 6724 0.1544 12.80 13288 0.3051 13.60 20707 0.4754 11.30 1888 0.0433 12.10 7518 0.1726 12.90 14152 0.3249 13.70 21716 0.4985 11.40 2517 0.0578 12.20 8313 0.1908 13.00 15017 0.3447 13.80 22725 0.5217 11.50 3146 0.0722 12.30 9107 0.2091 13.10 15953 0.3662 13.90 23735 0.5449 11.60 3862 0.0887 12.40 9901 0.2273 13.20 16889 0.3877 14.00 24744 0.5680 11.70 4577 0.1051 12.50 10695 0.2455 13.30 17825 0.4092 1 i I I i I - I I 9/10/98 . 1 11 :45 :18, am Sverdrup Civil Inc page 2 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECTPRE-DEV BASIN 4-6 ROUTED THROUGH POND"C" 1 STAGE DISCHARGE TABLE 1 I COMBINATION DISCHARGE ID No. COMBO2 Description: POND I"C" COMBO STRUCTURE Structure: PONDC2 Structure: Structure: RISER . Structure : Structure: 1 STAGE <--DISCHARGE---> STAG E <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) cfi ft) ---cfs ft) ---cfs ft) ---cfs 10.00 0.0000 10L80 0.2995 11.60 0.6469 12.40 1.2161 1 10.10 0.1059 101.90 0.3177 11.70 0.7101 12.50 1.2671 10.20 0.1498 11I.00 0.3349 11.80 0.7650 12.60 1.6236 10.30 0.1834 11'.10 0.3512 11.90 0.8955 12.70 2.2332 10.40 0.2118 111.20 0.3669 12.00 0.9747 12.75 2.6021 10.50 0.2368 11.30 0.3818 12.10 1.0431 10.60 0.2594 111.40 0.3963 12.20 1.1050 10.70 0.2802 11.50 0.5680 12.30 1.1623 I I I i 9/10/98 11 :45 :18 am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-6 ROUTED THROUGH POND"C" STAGE DISCHARGE TABLE 1 MULTIPLE ORIFICE j ID No. PONDC2 Description: POND, "C" DISCHARGE STRUCTURE Outlet Elev: 10 . 00 Elev: 8 . 25 ft, Orifice Diameter: 3 . 5130 in. Elev: 11.40 fti Orifice 2 Diameter: 4 . 2890 in. Elev: 11. 80 ft: Orifice 3 Diameter: 3 . 0700 in. STAGE <--DISCHARGE---> STAGE c--DISCHARGE---> STAGE c--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs 10.00 0.0000 10.00 0.0000 10.00 0.0000 10.00 0.0000 9/10/98 11 :45 : 18. am Sverdrup Civil Inc page 4 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-61ROUTED THROUGH POND"C" STAGE DISCHARGE TABLE RISER DISCHARGE ID No. RISER Description: POND ] "C" RISER Riser Diameter (in) : 12 . 00 elev: 12 . 50 ft Weir Coefficient . . . : 9 . 739 height : 12 . 75 ft Orif Coefficient . . : 3 . 782 increm: 0 . 10 ft STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> I ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs 12.50 0.0000 12.60 0.3080 12.75 1.2174 12.75 1.2174 12.50 0.01000 12.70 0.8711 i I I i i I 9/10/98 11 :45 :19 am Sverdrup Civil Inc page 5 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4-6 'ROUTED THROUGH POND"C" LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, PRE BASIN 4-6 0.00 0.26 PONDC COMB02 10.00 1 0.26 0.00 cf 2YR, PRE BASIN 4-6 0.00 1.26 PONDC COMB02 11.31 2 0.38 1946.03 cf 5YR, PRE BASIN 4-6 0.00 1.64 PONDC COMB02 11.47 3 0.52 2983.94 cf 10YR, PRE BASIN 4-6 0.00 2.12 PONDC COMB02 11.66 4 0.68 4281.20 cf 25YR, PRE BASIN 4-6 0.00 2.62 PONDC COMB02 11.88 5 0.87 5858.61 cf 50YR, PRE BASIN 4-6 0.00 2.67 PONDC COMB02 11.90 6 0.90 6007.94 cf 100YR, PRE BASIN 4-6 0.00 3.13 PONDC COMB02 12.10 7 1.04 7484.70 cf 1 l D File Input Hydrograph Storage Discharge LPool Proj : SWMP eeeeeeeeeeeeeeeeeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeee; MATCH INFLOW STO DIS PEAK PEAK OUT 0 o DESCRIPTION PEAK PEAK No.No. STG OUT HYD o ft112, RE BASIN 4 0 . 00 1.27 4C 4C 9 . 11 1. 02 8 2YR, PRE BASIN 4 0 . 00 10 . 06 4C 4C 9 . 21 10 . 06 9 0 iYR, PRE BASIN4 0 .100 11 . 63 4C 4C 9 . 22 11 . 63 10 0 OYR, PRE BASIN 4 0 . 00 13 .41 4C 4C 9 . 23 13 .41 11 25YR, PRE BASIN 4 0 . 00 14 . 99 4C 4C 9 .24 14 . 99 12 0 SOYR, PRE BASIN 4 0 . 00 15 .22 4C 4C 9 . 24 15 . 22 13 LOGY , PRE BASIN 4 0 . 00 17 .30 4C 4C 9 . 26 17.30 14 - 0 o 0 0 0 o - Done< Press any key to exit aeee=eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef i I anu: Perform Level pool computations using input table instructions PRe -0EvE IILoPMfiN i 5v9,FAc.E WrztlE, N1PwAGE meArr Peo5t LT SAS in.) 9 Ns y I y- Li--3 1-!-41 ,-k-5 A 4-‘ 1 5 u Q-ate i i i i i OLE/NSE 2A1 5 c o 5P21,06 4RouK. CAFE SEAR. IAAL.wPTF_2 = 9,L5 9/10/98 12 :5 : 8 am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4, ROUTED TO SPRINGBROOK STAGE STORAGE TABLE CUSTOM STORAGE ID No. 4C Description: POND4C 1 STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 6.00 0.0000 0.0000 8.30 25325 0.5814 10.60 63992 1.4691 12.90 150929 3.4649 6.10 952.40 0.0219 8.40 26627 0.6113 10.70 66270 1.5214 13.00 155909 3.5792 6.20 1905 0.0437 8.50 27929 0.6412 10.80 68549 1.5737 13.10 164079 3.7667 6.30 2857 0.0656 8.60 29231 0.6711 10.90 70827 1.6260 13.20 172248 3.9543 6.40 3810 0.0875 8.70 30533 0.7010 11.00 73105 1.6783 13.30 180418 4.1418 6.50 4762 0.1093 8.80 31836 0.7308 11.10 76405 1.7540 13.40 188588 4.3294 6.60 5714 0.1312 8.90 33138 0.7607 11.20 79706 1.8298 13.50 196758 4.5169 6.70 6667 0.1530 9.00 34440 0.7906 11.30 83006 1.9056 13.60 204927 4.7045 6.80 7619 0.1749 9.10 36028 0.8271 11.40 86307 1.9813 13.70 213097 4.8920 6.90 8572 0.1968 9.20 37617 0.8636 11.50 89607 2.0571 13.80 221267 5.0796 I 7.00 9524 0.2186 9.30 39205 0.9000 11.60 92907 2.1329 13.90 229436 5.2671 7.10 10713 0.2459 9.40 40793 0.9365 11.70 96208 2.2086 14.00 237606 5.4547 7.20 11903 0.2733 9.50 42382 0.9729 11.80 99508 2.2844 14.10 252061 5.7865 7.30 13092 0.3006 9.60 43970 1.0094 11.90 102809 2.3602 14.20 266517 6.1184 7.40 14282 0.3279 9.70 45558 1.0459 12.00 106109 2.4359 14.30 280972 6.4502 7.50 15471 0.3552 9.80 47146 1.0823 12.10 111089 2.5503 14.40 295427 6.7821 7.60 16660 0.3825 9.90 48735 1.1188 12.20 116069 2.6646 14.50 309883 7.1139 7.70 17850 0.4098 10.00 50323 1.1553 12.30 121049 2.7789 14.60 324338 7.4458 7.80 19039 0.4371 10.10 52601 1.2076 12.40 126029 2.8932 14.70 338793 7.7776 7.90 20229 0.4644 10.20 54879 1.2599 12.50 131009 3.0076 14.80 353248 8.1095 8.00 21418 0.4917 10.30 57158 1.3122 12.60 135989 3.1219 14.90 367704 8.4413 8.10 22720 0.5216 110.40 59436 1.3645 12.70 140969 3.2362 8.20 24022 0.5515 10.50 61714 1.4168 12.80 145949 3.3505 I I I - I 1 9/10/98 12 :5 : 8 am Sverdrup Civil Inc pag 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4, ROUTED TO SPRINGBROOK STAGE DISCHARGE TABLE CUSTOM DISCHARGE ID No. 4C Description: POND4C STAGE <--DILSCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> I I ft) -cfs ft) -cfs ft) -cfs ft) cfs 1 9.15 0.0000 10.95 136.53 12.75 198.59 14.55 247.32 9.25 16.126 11,.05 140.61 12.85 201.57 14.65 249.75 9.35 32.251 11.15 144.44 12.95 204.55 14.75 252.18 9.45 48.377 11.25 148.27 13.05 207.44 14.85 254.61 9.55 59.I910 11.35 152.09 13.15 210.25 14.95 257.04 9.65 66.850 11L45 155.92 13.25 213.06 15.05 259.43 9.75 73.790 11',.55 159.56 13.35 215.87 15.15 261.77 9.85 80.730 111.65 163.03 13.45 218.68 15.25 264.11 9.95 87.670 1111.75 166.49 13.55 221.41 15.35 266.45 10.05 93.726 111.85 169.95 13.65 224.08 15.45 268.79 10.15 98.898 11,.95 173.42 13.75 226.74 15.55 271.09 10.25 104.07 12.05 176.75 13.85 229.40 15.65 273.34 10.35 109.24 121.15 179.94 13.95 232.07 15.75 275.60 10.45 114.41 12.25 183.14 14.05 234.67 15.85 277.86 I 10.55 119.17 12.35 186.34 14.15 237.21 15.95 280.11 10.65 123.51 121.45 189.53 14.25 239.75 16.05 281.24 10.75 127.85 121.55 192.62 14.35 242.29 10.85 132.19 12..65 195.60 14.45 244.83 1 j I i I I I Page 1 of 3 Pressure Pipe Analysis & Design Circular Pipe Worksheet Name: Practice Track Description: Practice Track Outlet Solve For Discharge Given Constant Data; Pressure @ 1 0 . 00 Elevation @ 2 9 . 15e— 2`((' TA11-waTER At SPRINJG[iRoolc. CRGE1. Pressure @ 1 0 . 00 Discharge 0 . 00 Diameter 36 . 00 Length 45 . 00 Hazen-Williams C 100 . 0000 Variable Input Data Minimum Maximum Increment By Elevation @ 1 9 . 00 16 . 00 0 . 10 BA51N y D Sc.v4aRGE R TING GvrtvF CALCoLA oNS Fo( 5uB-6AsiNS `i—1 1.4-2/ -3 y-! '-{-5/ d. y-4, R 60 i NtioUGN MAC(' tc.E RAcK 7ti 5PR,INGc32OC . GKEEK ARE—Q'V ELoPmErj i 5 v 0.FAc.E w p.'(ER, !'lfjn)A6 E M.EN T Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 i I Page 2 of 3 V IABLE COMPUTED El v. Pressure Elev. ' Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1_ @ 2 @ 2 gpm in ft f ps . ft psi 9 . 00 0 . 00 9 . 15 ' 0 . 00 -16031.45 36 . 00 45 . 00 100 . 00 9 .10 0 . 00 9 . 15 0 . 00 -8857 . 83 36 . 00 45 . 00 100 . 00 9 . 0 0 . 00 9 . 15 ; 0 . 00 8857. 83 36 . 00 45 . 00 100 . 00 9 . 0 0 . 00 9 . 15 0 . 00 16031 .45 36 . 00 45 . 00 100 . 00 9 . 0 0 . 00 9 . 15 0 . 00 21123 . 76 36 . 00 45 . 00 100 . 00 9 . 0 o . od 9 .15 0 . 00 25332 . 63 36 . 00 45 . 00 100 . 00 9 . 0 0 . 00 9 . 15 0 . 00 29014 .71 36 . 00 45 . 00 100 . 00, 9 . 0 0 . 00 9 . 15 0 . 00 32335 .48 36 . 00 45 . 00 100 . 00 9 . 0 0 . 00 9 .15 0 . 00 35388 . 06 36 . 00 45 . 00 100 . 00, 9 . 0 0 . 00 9 . 15 0 . 00 38231. 08 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 . 15 0 . 00 40904 .37 36 . 00 45 . 00 100 . 00 10. 0 0 . 00 9 .15 0 . 00 43436 .44 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 .15 ; 0 . 00 45848 .56 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 . 15 0 . 00 48157 . 10 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 . 15 , 0 . 00 50374 . 98 36 . 00 45 . 00 100 . 00 1 10 . 0 0 . 00 9 . 15 0 . 00 52512 .63 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 .15 0 . 00 54578 . 58 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 .15 . 0 . 00 56579 .96 36 . 00 45 . 00 100 . 00 0 . :0 0 . 00 9 . 151 0 . 00 58522 . 77 36 . 00 45 . 00 100 . 00 0 . •0 0 . 00 9 . 15 0 . 00 60412 . 12 36 . 00 45 . 00 100 . 00' 11. .0 0 . 00 9 . 15 . 0 . 00 62252 .42 36 . 00 45 . 00 100 .001 11. 0 0 . 00 9 . 15 0 . 00 64047.50 36 . 00 45 . 00 100 . 00 11. .0 0 . 00 9 . 15'0 . 00 65800 . 71 36 . 00 45 . 00 100 . 00 11 . 0 6 . 66 9. 151,0 . 00 67515 . 00 36 . 00 45 . 00 100 . 00 11. ,.0 0 . 00 9 . 15 0 . 00 69192 . 99 36 . 00 45 . 00 100 . 00 11. ^0 6 . 66 9 .15 0 . 00 70837 . 00 36 . 00 45 . 00 100 .00' 11 . :0 0 . 00 9 . 15 0 . 00 72449 . 13 36 . 00 45 . 00 100 . 00 11 . 0 0 . 00 9 . 15 0 . 00 74031.27 36 .00 45 . 00 100 . 00I 11. :0 0 . 00 9 . 15 , 0 . 00 75585 .12 36 . 00 45 . 00 100 . 00 1 11 . •0 o . od 9 . 15 ' . 0 . 00 77112 .21 36 . 00 45 . 00 100 . 001 12 . 00 6 . 00 9 .15 0 . 00 78613 . 97 36 . 00 45 . 00 100 . 00 12 . 10 0 . 00 9 . 15 0 . 00 80091. 68 36 . 00 45 . 00 100 . 00 ' 12 .20 0 . 00 9 . 15 0 . 00 81546 . 52 36 . 00 45 . 00 100 . 00 12 .30 0 . 00 9 . 15 . 0 . 00 82979 .58 36 . 00 45 . 00 100 . 00 12 .40 0 . 00 9 .15 0 . 00 84391. 85 36 . 00 45 . 00 100 . 00 12 .50 0 . 00 9 . 15 , 0 . 00 85784 .28 36 . 00 45 . 00 100 . 00 ! 12 . 60 0 . 00 9 .15 0 . 00 87157 . 71 36 . 00 45 . 00 100 . 00 12 . 70 0 . 00 9 . 15 0 . 00 88512 . 95 36 . 00 . 45 . 00 100 . 00 12 . 80 0 . 00 9 . 15 0 . 00 89850 .74 36 .00 45 . 00 100 . 00 12 . 90 0 . 00 9 . 15 0 . 00 91171. 77 36 . 00 45 . 00 100 . 00 Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 I Page 3 of 3 VARIABLE COMPUTED Elev. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2 @ 2 gpm in ft ft psi ft psi 13 . 00 0 . 00 9 .15 0 . 00 92476 . 70 36 . 00 45 . 00 100 . 00 13 .10 0 . 00 9 .15 0 . 00 93766.12 36 . 00 45 . 00 100 . 00 13 .20 0 . 00 9 .15 0 . 00 95040. 61 36 . 00 45 . 00 100 . 00 13 .30 0 . 00 9 . 15 0 . 00 96300 . 71 36 . 00 45 . 00 100 . 00 13 .40 0 . 00 9 .15 0 . 00 97546 . 92 36 . 00 45 . 00 100 . 00 13 .50 0 . 00 9. 15 0 . 00 98779. 70 36 . 00 45 . 00 100 . 00 13 . 60 0 . 00 9 .15 0 . 00 99999 . 52 36 . 00 45 . 00 100 . 00 13 .70 0 . 00 9 .15 0 . 00 101206 .79 36 . 00 45 . 00 100 . 00 13 . 80 0 . 00 9 .15 0 . 00 102401 . 92 36 . 00 45 . 00 100 . 00 11 13 . 90 0 . 00 9 . 15 0 . 00 103585.29 36 . 00 45 . 00 100 . 00 1 14 . 00 0 . 00 9 .15 0 . 00 104757.24 36 . 00 45 . 00 100 . 00 14 .10 0 . 00 9 .15 0 . 00 105918 . 13 36 . 00 45 . 00 100 . 00 14 .20 0 . 00 9 . 15 0 . 00 107068 .29 36 . 00 45 . 00 100 . 00 14 .30 0 . 00 9 .15 0 . 00 108208 . 01 36 . 00 45 . 00 100 . 00 14 .40 0 . 00 9.15 0 . 00 109337 . 60 36 . 00 45 . 00 100 . 00 14 .50 0 . 00 9 . 15 0 . 00 110457.33 36 . 00 45 . 00 100 . 00 14 . 60 0 . 00 9 .1,5 0 . 00 111567 .48 36 . 00 45 . 00 100 . 00 14 . 70 0 . 00 9 .15 0 . 00 112668 .30 36 . 00 45 . 00 100. 00 4 . 80 0 . 00 9 . 1,5 0 . 00 113760 . 03 36 . 00 45 . 00 100 .00 4 . 90 0 . 00 9 . 15 0 . 00 114842 . 90 36 . 00 45 . 00 100 . 00 15 . 00 0 . 00 9 . 15 0 . 00 115917 . 15 36 . 00 ' 45 . 00 .100 . 00 15 . 10 0 . 00 9 .15 0 . 00 116982 . 98 36 . 00 45 . 00 100 . 00 15 . 20 0 . 00 9 . 15 0 . 00 118040 . 60 36 . 00 45 . 00 100 . 00 15 .30 0 . 00 9 . 15 0 . 00 119090 .22 36 . 00 45 . 00 100 . 00 15 .40 0 . 00 9 . 15 0 . 00 120132 . 01 36 . 00 45 . 00 100 . 00 15 . 50 0 . 00 9 .15 0 . 00 121166 .16 36 . 00 45 . 00 100 . 00 15 . 60 0 . 00 9 .15 0 . 00 122192 . 84 36 . 00 45 . 00 100 . 00 15 . 70 0 . 00 9 . 15 0 . 00 123212 .23 36 . 00 45 . 00 100 . 00 15 . 80 0 . 00 9 . 15 0 . 00 124224 .49 36 . 00 45 . 00 100 . 00 1 15 . 90 0 . 00 9 .15 0 . 00 125229 . 76 36 . 00 45 . 00 100 . 00 16 . 00 0 . 00 9 .15 0 . 00 126228 .21 36 . 00 45 . 00 100 . 00 16 . 10 0 . 00 9 . 15 0 . 00 127219 . 98 36 . 00 45 . 00 100 . 00 Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, 1Inc . * 37 Brookside Rd * Waterbury, Ct 06708 1 1 12 : 5 : 9 am Sverdrupa e 39/10/98 Civil Inc p 9 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT PRE-DEV BASIN 4, ROUTED TO SPRINGBROOK LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- c-STAGE> id (cfs) VOL (cf) WQ, PRE BASIN 4 0.00 1.27 4C 4C 9.11 8 1.02 36228.57 cf 2YR, PRE BASIN 4 0.00 10.06 4C 4C 9.21 9 10.06 37813.24 cf 5YR, PRE BASIN 4 0.00 11.63 4C 4C 9:22 10 11.63 37968.31 cf 10YR, PRE BASIN 4 0.00 13.41 4C 4C 9.23 11 13.41 38143.14 cf 25YR, PRE BASIN 4 0.00 14.99 4C 4C 9.24 12 14.99 38298.56 cf 50YR, PRE B IN 4 j 0.00 15.22 4C 4C 9.24 13 15.22 38321.41 cf 100YR, PRE BASIN 4 0.00 17.30 4C 4C 9.26 14 17.30 38526.08 cf I I I I III t I I I I I I I D File. Input Hydrograph .Storage . Discharge LPool Proj : SWMP ieeeeeeeeeeeeeeeeeeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeee o - MATCH INFLOW STO DIS PEAK PEAK OUT o DESCRIPTION PEAK .PEAK No.No. STG OUT HYD 0 o 0 WQ, POST A-1 & A-2 0 . 00 6 . 70 CSTC V-WEIR 8 . 82 0 . 18 8 0 1 2YR, POST A-1 7 A-2 0 . 00 43 .21 CSTC V-WEIR 9 . 56 -5 . 02 9 0 - 5YR, POST A-1 & A-2 0 . 00 55 . 65 CSTC V-WEIR 9 . 71 6 . 93 10 10YR, POST A-1 & A-2 0 , 00 71 . 51 CSTC V-WEIR 9 . 89 9 . 79 11 25YR, POST A-1 & A-2 0 . 00 87 . 55 CSTC V-WEIR 10 . 05 12 . 98 12 O1 50YR, POST A-1 & A-2 0 . 00 89 . 16 CSTC V-WEIR 10 . 07 13 .29 13 0 100YR, POST A-1 & A-2 0 , 00 103 . 67 CSTC V-WEIR 10 . 20 17. 15 •14 o o o o o o --- 1 o Done< Press any key to exit aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef Menu: Perform Level pool computations using input table instructions eoS'C - OEvE>~oPMEVI SuckFPoLE ' WA'CER MAn)AGEMan,T PRoSEcT 6AsiNS A-\ a A-2 RoeVEQ 4-4Ro0 GN E FO.c.F0 CSt C PonJD OVER V^Na'Cc.N R Cv Pt REP% EAti 7A«wP%-veR IN CS-cc, 4)61v0 IS APPRoX. 6.15 (See 8AsiN5 p,--\ ,A-D, .i A=3 Roo-rED f hk R o oco4 'Dc=LZA I 9/10/98 10 :18 :54 am Sverdrup Civil Inc p ge 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BSN A1&A2, CSTC ROUTED TO DELTA 1 STAGE STORAGE TABLE CUSTOM STORAGE ID No. CSTC Descripion: CSTC STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> I ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- I 8.50 0.01000 0.0000 9.70 502749 11.542 10.90 1116440 25.630 12.10 1865645 42.829 8.60 38363 0.8807 9.80 547168 12.561 11.00 1169821 26.855 12.20 1936568 44.457 8.70 76726 1.7614 9.90 591587 13.581 11.10 1232311 28.290 12.30 2007492 46.086 8.80 115089 2.6421 10.00 636006 14.601 11.20 1294801 29.725 12.40 2078415 47.714 8.90 1531452 3.5228 10,.10 689388 15.826 11.30 1357291 31.159 12.50 2149339 49.342 9.00 1911815 4.4035 10;.20 742769 17.052 11.40 1419781 32.594 12.60 2220262 50.970 9.10 236234 5.4232 101.30 796151 18.277 11.50 1482271 34.028 12.70 2291186 52.598 9.20 2801653 6.4429 10.40 849532 19.503 11.60 1544761 35.463 12.80 2362109 54.227 9.30 325072 7.4626 101.50 902914 20.728 11.70 1607251 36.897 12.90 2433033 55.855 9.40 369491 8.4824 10.60 956295 21.954 11.80 1669741 38.332 0.00 2503956 57.483 9.50 413911 9.5021 101.70 1009677 23.179 11.90 1732231 39.767 9.60 45830 10.522 10.80 1063058 24.404 12.00 1794721 41.201 II I I I If 9/10/98 10 : 18 :54 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BSN A1&A2, CSTC ROUTED TO DELTA STAGE DISCHARGE TABLE CUSTOM DISCHARGE , ID No. V-WEIR Description: V-WEIR STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs 8.70 0.0000 9.50 4.2774 10.30 122.54 11.10 201.82 8.80 0.1450 9.60 5.4425 10.40 131.57 11.20 212.82 8.90 0.3801 9.70 6.7779 10.50 140.86 11.30 224.04 9.00 0.7102 9.80 8.2911 10.60 150.41 11.40 235.49 9.10 1.1534 9.90 9.9894 10.70 160.21 11.50 246.33 9.20 1.7218 10.00 11.880 10.80 170.25 9.30 2.4256 10.10 13.969 10.90 180.54 9.40 3.2746 10.20 16.264 11.00 191.06 I CSTC Discharge Structure to Delta Area 120°V-Notch Weir) Tailwater Elev.= 8.75 Stage Hyd.Head Hyd.Head Weir Coefficient Actual No.of sides Effective Free Submerged Added Flow Total ft) Upstream Downstream Height C1(1) Width contracted Width Flowrate Flowrate from V-Notch Flowrate Hup(ft) Hdo.(ft) Y(ft)banaat(ft) N ball.(ft)(2) Q(cfs)( 3) Q(cfs)(4) Q(cfs)(5) Q(cfs) 8.5 0.0 0.3 8.5 0.00 0 0.00 8.6 0.1 0.3 8.5 0.01 0 0.00 8.7 0.2 0.3 8.5 0.08 0 0.00 8.8 0.3 0.3 8.5 1 0.21 0 0.14 8.9 0.4 0.3 8.5 0.44 0 0.38, 9.0 0.5 I 0.3 8.5 0.77 1 0.71: 9.1 0.6 0.3 8.5 1.21 1 1.15 9.2 0.7 I 0.3 8.5 1.78 2 1.72 9.3 0.8 0.3 8.5 2.48 2 2.43, 9.4 0.9 0.3 8.5 I 3.33 3 3.27 9.5 1.0 0.3 8.5 4.33 4 4.28 9.6 1.1 0.3 8.5 5.50 5 5.44! 9.7 1.2 0.3 8.5 6.83 7 6.78 9.8 1.3 0.3 8.5 8.34 8 8.29, 9.9 1.4 0.3 8.5 10.04 10 9.99,. 10.0 1.5 0.3 8.5 I 11.93 12 11.88 10.1. 1.6 0.3 8.5 I 14.02 14 13.97 10.2 1.7 0.3 8.5 I 16.32 16 16.26 10.3 1.8 0.3 8.5 0.623 13.1 2 13.06 105 105 18 122.54 10.4 1.9 I 0.3 8.5 0.623 13.1 2 13.06 114 114 18 131.57 10.5 2.0 j 0.3 8.5 0.624 13.1 2 13.06 123 123 18 140.86 10.6 2.1 0.3 8.5 0.625 13.1 2 13.06 133 133 18 150.41 - 10.7 2.2 0.3 8.5 0.626 13.1 2 13.06 143 142 18 160.2',1 10.8 2.3 0.3 8.5 I 0.627 13.1 2 13.05 153 153 18 170.2;5 10.9 2.4 0.3 8.5 0.628 13.1 2 13.05 163 163 18 180.54 11.0 2.5 0.3 8.5 0.629 13.1 2 13.05 174 173 18 191.06 11.1 2.6 0.3 8.5 0.630 13.1 2 13.05 184 184 18 201.82 11.2 2.7 0.3 8.5 0.631 13.1 2 13.05 195 195 18 212.82 11.3 2.8 0.3 8.5 0.632 13.1 2 13.04 206 206 18 224.04 11.4 2.9 0.3 8.5 0.632 13.1 2 13.04 218 218 18 235.4:9 11.5 3.0 0.5 8.5 0.633 13.1 2 13.04 230 229 18 246.33 Weir transitions from V-Notch to Contracted Sharp-Crested Weir at a Stage of 10.26 For V-Notch Weir: 3) Q=2.5 tan(0/2) IH52 (Brater&King,Handbook of Hydraulics,eq.5-45) 3) If 0=120°,Q=4J33 H5'2(Brater&King,Hiandbook of Hydraulics,eq.5-48b) I 1 For Contracted SharpCrested Weir: I 1 1) C,=[0.6035+0.0813(H/Y)+(0.000295/Y)]'[1+(0.00361/H)]32 (Rehbock) 2) berc=bactuai-(0.1)(N)(H) 3) Q=2/3(C,)(bex)(2g)--(H)3'2 1 52 0 3854) %„b=Qo-ee[1-(Hdom Hup) ] 5) Flow from V-Notch Weir is added to flow from rectangular weir. 1• 1 014002\2220\engr XBCALC12.XLS[V-Notch Weir(Submerged)] i 46e tioN .....yr.vivaxit, oix-p6T-.- 4, 04, POO" elitZy' r ' i1Y0 OI>>NI r.Th rra, It [rya fr, L'a'u 'r('d - r+o u adwvp °t turi"t to v"witlz flu --. i ref .t't L'1 + t{ r H:'..-.. Mo 1 . 410 ws 14 190-"is .,. r.,„ .2.w , ,,, iim s. qhl% tr. sw HZ Z' 9'4 y 4 1610 11 *44 V/ 4% •7 i Lid 1 i 5 lig priiin ,,,,.„, ACTti ;J 5 1 ,; r1 I . i; 0-1 il 4 .D1t p '' w N I 1 vArlD cope A-- WA a tl, ILA C1104' r f %'i Mph'' . A-t,3 ry ( oulA . pt Ll. ** q Za/T0'd LLSq Mki9911.0 Z0-90'96ST 00££ We 90 t 01 SEI1I1I s WOZld +' • 9/10/98 10 : 18 :55 am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BSN A1&A2i CSTC ROUTED TO DELTA LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, POST A-1 & A-2 0.00 6.70 CSTC V-WEIR 8.82 8 0.18 3 ac-ft 2YR, POST A-1 7 A-2 0.00 43.21 CSTC V-WEIR 9.56 9 5.02 10 ac-ft 5YR, POST A-1 & A-2 0.00 55.65 CSTC V-WEIR 9.71 10 6.93 12 ac-ft 10YR, POST A- & A-2 0.00 71.51 CSTC V-WEIR 9.89 11 9.79 13 ac-ft 25YR, POST A-1 & A-2 0.00 87.55 CSTC V-WEIR 10.05 12 12.98 15 ac-ft 50YR, POST A-L1 & A-2 0.00 89.16 CSTC V-WEIR 10.07 13 13.29 15 ac-ft 100YR,POST A-1 & A-2 0.00 103.67 CSTC V-WEIR 10.20 14 17.15 17 ac-ft D File Input Hydrdgraph Storage Discharge LPool Proj : SWMP ieeeeeeeeeeeeeeeeeeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeeeeeeeeee; o MATCH INFLOW STO DIS PEAK PEAK OUT o DESCRIPTION PEAK PEAK No.No. STG OUT HYD 0 o WQ, POST BASIN A 0. 00 0 . 22 DELTA PSTA 7 . 80 0 . 00 1 2YR, POST BASIN A 0. 00 5 . 33 DELTA PSTA 8 . 71 5 .29 2 5YR, POST BASIN A 0. 00 7 . 33 DELTA PSTA 8 . 75 7 . 31 3 10YR, POST BASIN A 0. 00 10 . 36 DELTA PSTA 8 . 81 10 .32 4 25YR, POST BASIN A 0. 00 13 . 73 DELTA PSTA 8 . 89 13 . 72 5 0 50YR, POST BASIN A 0 . 00 14 . 08. DELTA PSTA 8 . 89 14 . 05 6 0 100YR, POST BASIN A 0i. 00 18 . 13 DELTA PSTA 8 . 97 17 . 85 7 O 0 o 0 0 0." o 1 o Done< Press any key to exit 0 aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef I Menu: Perform Level pool computations using input table instructions 1 Qb5"T - DEvEL.OPr\VNT 1 5v(kF P.cE y,;ick-c GR U\kr.AG /A'ENT QR,ole c.'t' ov-tav "V4R.o0C '4 tjAS NS A-1 A a, 4- A 3 1s OEL.TA 0150HP.R,DE VAVL.T co SQ .v'J 13(LotA C(1.6o. D- ' 6PI "TpoL t.IA1Fk s i?:). Go i I I 9/10/98 10 :23 :301am Sverdrup Civil Inc page 1 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BSN A,DELTA ROUTED TO SPRINGBRK STAGE STORAGE TABLE I I I CUSTOM STORAGE ID No. DELTA Description: DELTA 1 I I STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf-i- --Ac-Ft- (f ) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 1 7.50 0.0000 0.0000 840 70453 1.6174 9.30 157876 3.6243 10.20 265457 6.0940 7.60 6984 0.1603 8:50 79336 1.8213 9.40 169251 3.8855 10.30 279434 6.4149 7.70 13968 0.3207 860 88218 2.0252 9.50 180626 4.1466 10.40 293411 6.7358 7.80 20953 0.4810 870 97101 2.2291 9.60 192001 4.4077 10.50 307389 7.0567 7.90 27937 0.6413 8!80 105984 2.4331 9.70 203376 4.6689 10.60 321366 7.3775 8.00 34921 0.8017 8.90 114867 2.6370 9.80 214752 4.9300 10.70 335343 7.6984 I 1 8.10 43804 1.0056 9.00 123750 2.8409 9.90 226127 5.1912 10.80 349320 8.0193 8.20 52687 1.2095 9.10 135125 3.1020 10.00 237502 5.4523 10.90 363298 8.3402 8.30 61570 1.4134 9J20 146500 3.3632 10.10 251479 5.7732 1 i 9/10/98 10 :23 :30 am Sverdrup .Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BSN A,DELTA ROUTED TO SPRINGBRK STAGE DISCHARGE TABLE CUSTOM DISCHARGE I ID No. PSTA Description: CSTC=OUT STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs 8.60 0.0000 10.00 41.370 11.40 81.054 12.80 128.54 8.70 4.8150 10.10 44.000 11.50 84.120 12.90 132.17 8.80 9.6300 10.20 46.630 11.60 87.378 13.00 135.80 8.90 14.445 1I0.30 49.260 11.70 90.636 13.10 139.61 9.00 19.260 10.40 51.890 11.80 93.894 13.20 143.42 9.10 21.378 10.50 54.520 11.90 97.152 13.30 147.23 9.20 23.496 10.60 57.374 12.00 100.41 13.40 151.04 9.30 25.614 10.70 60.228 12.10 103.86 13.50 154.85 9.40 27.732 10.80 63.082 12.20 107.31 13.60 158.83 9.50 29.850 1I0.90 65.936 12.30 110.76 13.70 162.81 9.60 32.154 11.00 68.790 12.40 114.21 13.80 166.80 9.70 34.458 11.10 71.856 12.50 117.66 13.90 170.78 9.80 36.762 11.20 74.922 12.60 121.29 14.00 174.76 9.90 39.066 11.30 77.988 12.70 124.92 1 I i CSTC Delta Area Discharge Vault Summary Basin A Discharge Structure to Springbrook Creek) Stage Vault Inlet Capacity Vault Interior Capacity Vault Outlet Capacity Actual Vault ft)(1) Contracted Broad- 18"RCP Total Inlet Broad-Crested Weir 36"DIP Outlet Release Rate Crested Weir(cfs)(2) Inlet(cfs)( 3) Capacity(cfs)(4) Stoplogs)(cfs)(5) cfs)(6) cfs)(7) 8.60 0 0 0 0 0 0 9:00 0 19 19 — - 67 80- 19 9.50 0 30 30 125 124 30 10.00 3 38 41 188 157 41 10.50 10 45 55 259 185 55 11.00 18 51 69 337 210 69 11.50 28 56 84 422 233 84 12.00 39 61 100 514 254 100 12.50 52 66 118 612 273 118 13.00 65 70 136 717 291 136 13.50 80 75 155 828 309 155 14.00 96 79 175 946 325 175 Notes: 1) 2-year tailwater in Springbrook Creek= 8.60 (Table 8-2, ESGRWSP, R.W. Beck, Dec 1996) 2) Refer to CSTC Delta Area Discharge Vault Element 1 for details. 3) Refer to CSTC Delta Area Discharge Vault Element 2 for details. 4) Total vault inlet capacity is sum of contracted broad-crested weir(2) capacity and 18" RCP(3) capacity 5) Refer to CSTC Delta Area Discharge Vault Element 3 for details. 6) Refer to CSTC Delta Area Discharge Vault Element 4 for details. 7) Vault inlet capacity, internal capacity and outlet capacity were compared to determine the actual release rate from the vault. 013747\2210\engr\KBCALC15.XLS[Summary] 16•-0" 1 4-- NH OPENING MH STEP TVP 1\- L.3x3 63x GALV•TYP BILCO DOOR POINT OF TIMBER ' IDENTIFYING STOP• I I r 1 COORDINATES LOGS-N1 1 • 3r DIP CL 53 FLxPE II 1 1_0/ TO SPRINGBROOK CREEK 1 b N—n I ICe4 01 81(o) ter CONC-/ I i ( I• BOLTED FLANGED JOINT SD Ili L J CYLINDRICAL A. EENEBY SCREEN OVERFLOW 1 , IT-60 WITH _ OPENINGGW 1------1- r JOHNSON SCREENS OR APPROVED EQUAL s •.;:; b b NOTE: FOR DETAILS NOT SHOWNISEE1580(D)L f - . I • If PVC DRAIN DIP CAST INTO er ACCES•SCOVER CONCRETE Z YR FL?v,ze .S`r 4.`r PVC BALL VALVE EVEArr ON 5P,C[N(Blfoo/'-SPRINGBROOK CREEK • DETAIL OUTLET STRUCTURE C_/lEC/< -EL S. fp CASLE:!NONE 1C1Q I)) r a•-or tO NH OPENING 1 ;,•: \/\ J, ..\: • , DOOR OPENING L+// i_ OVIDE REMOVABLE GRAT I -- NOTE:W/ 1•• SMOOTH GALV STEEL BARS AT 6' OC VERTICAL EL. 12.0 EL.15.2 STOP LOG ANCHOR TO ORIENTATION CONSIST OR 5%8•4 BOOT' LOG ANGLE GUIO NUTS AND WASHERS PAS_ 1 THROUGH BOTH STOP L0 ANGLE GUIDES ON BOTH WILLOW PLANTINGS ov .ow Cr - SIDES I 4 36'6 OUTLET SPACING 1 E 9: STOP LOG ANCH• A`:_; v16• SO BEVEL TO ram. EL 7.5MATCtt *LOPE. i*••i i••i•••• • I L•EL: 6. 1 I.E. EI- 5.9 P • i i:•`i i i i •%4•:•I.E. EL5.40 1 1 I.E. EL 5.4 0.42% I I' Y\ a I • PVC I i DRAIN LEVEL 1 3/4•0 EPDXY ANCHOR BOLTS. r• r NUTS AND WASHERS 6"•EMBEDMENT 4• O 12' O.C. 4 . • I 4 6•x12• TIMBER EL 1.0 STOP LOGS r'•4 • v /. N1 • ...I" • • • • • • Y .• r II .a • •, %• . N. SPRINGBROOK CREEK I SECTION OUTLET STRUCTURE SCALE: NONE I:0 0) SouKE : CSTc Sure:.r_ O?vELoPMENT STott1"\ ORAINM(E DETAILS -SHEET 5 DRA9W6 1C0yCW) i ' CSTC Delta Area Discharge Vault Element 1 2' x 3' Overflow Contracted Broad-Crested Weir) Stage Hydraulic Weir Coefficient Actual No.of sides Effective Flowrate 1) 3) ft)Head Height C1 Width contracted Width Q(cfs) H(ft) Y',(ft) bactual(ft) N belt.(ft)(2) 9.5 0.0 18.5 0.000 3.0 2 3.00 0 10.0 0.5 18.5 0.615 3.0 2 2.99 3 10.5 1.0 8.5 0.616 3.0 2 2.98 10 11.0 1.5 8.5 0.620 3.0 2 2.97 18 11.5 2.0 8.5 0.624 3.0 2 2.96 28 12.0 2.5 I 8.5 0.629 3.0 2 2.95 39 12.5 3.0 18.5 0.633 3.0 2 2.94 52 13.0 3.5 18.5 0.638 3.0 2 2.93 65 13.5 4.0 18.5 0.643 3.0 2 2.92 80 j 1 14.0 4.5 18.5 0.647 3.0 2 2.91 96 1 Notes: 1) C1=[0.6035+0.0813(H/Y)+(0.000295/Y)]*(1+(0.00361/H)] (Rehbock) 2) beff=bactuai-(0.1)(N)(H) 3) Q=2/3(C1)(beff)(2g)1t2(H)F2 CS,TC Delta Area Discharge Vault Element 3 Submerged Supressed Broad-Crested Weir, Stoplogs) Stage Hyd.Head Hyd Head Weir Coefficient Actual Flowrate Flowrate 1) 2) ft) Upstream Downstream Height C1 Width Free Flow Submerged Hup(ft) Hdown(ft) Y(ft) bactual(ft) Qfree(cfs)(3) Qsub.(cfs)(4) 8.60 1.1 1.10 6.5 0.620 16.0 61 0 1 9.00 I 1.5 1.10 6.5 0.625 16.0 98 67 9.5 I 2.0 1.10 6.5 0.630 16.0 153 125 10.0 2.5 1.10 6.5 0.636 16.0 215 188 10.5 3.0 1.10 6.5 0.642 16.0 286 259 11.0 3.5 1.10 6.5 0.648 16.0 363 337 11.5 4.0 1.10 6.5 0.654 16.0 448 422 12.0 I 4.5 1.10 6.5 0.661 16.0 540 514 12.5 I 5.0 1.10 6.5 0.667 16.0 638 612 13.0 5.5 1.10 6.5 0.673 16.0 . 743 717 13.5 6.0 1.10 6.5 0.679 16.0 854 828 14.0 I 6.5 1.10 6.5 0.685 16.0 972 946 Notes: 1) 2-year tailwater in Springbrook Creek=8.60(Table 8-2, ESGRWSP, R.W. Beck, Dec 1996) 2) C1 1 [0.6035+0.0813(li/Y)+(0.000295m]*[1+(0.00361/H)] (Rehbock) 3) Qtre le=2/3(C1)(bactual)(29)1(Hup) 4) Qsub=()free[1 -(Hdown/Hup)3n]osas 013893122201engr\KBCALC15.XLS[E1andE3) Page 1 of 3 Pressure Pipe Analysis & Design Circular Pipe Worksheet Name: basin 3 pre-dev Description: Basin 3 Outlet 18" RCP Solve For Discharge ' Given Constant Data; Pressure @1 0 . 00 Elevation @ 2 8 . 60 — Z.iR "NJ Al SPAANCBMolc. cr ecy-• Pressure @, 1 0 .00 Discharge ; 45326 .53 Diameter 18 . 00 Length 24 . 00 Hazen-Williams C 140 . 0000 Variable Input Data Minimum Maximum Increment By Elevation @ 1 8 . 60 16 . 00 0 .10 I BAS1r " : 18 RCP INLET -co C.or.rnto STRV c-r RE. w z.\ka, Ac.Q ( , s 1f\olt. cw1'c FLEW N V Open Channel Flow Module, Version 3 .11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 Page 2 of 3 J IABLE COMPUTED i_ El v. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2 @ 2 gpm in ft f1 psi ft psi U able to compute this instance. 8. 0 0 .00 8.60 0.00 4090 . 00 18 .00 24 . 00 140 . 00 8 . 0 0 .00 8 .60 0 . 00 5946 .75 18 . 00 24 . 00 , 140 . 00 8 . 0 0 . 00 8 .60 0 .00 7402 .34 18 . 00 24 .00 140 . 00 9 .00 0 . 00 8 . 60 0 .00 8646 .41 18 .00 24 . 00 140 . 00 9 . 0 0 .00 8 .60 0 . 00 9753 . 6.5 18 . 00 24 . 00 140 . 00 9 . ' 0 0 . 00 8.60 , 0 . 00 10762 .79 18 . 00 24 .00 140 . 00 9 . ' 0 0 . 00 8 .60 , 0 . 00 11697. 05 18 . 00 24 .00 140 . 001 9 . ' 0 0 . 00 8.60 ' 0 .00 12571. 64 18 . 00 24 . 00 140 . 00', 9. ' 0 0 .00 8 . 69 0 .00 13397.21 18 . 00 24 . 00 140 .00 9. .0 0 .00 8 .69 0 .00 14181.54 18 .00 24 .00 140.00 9. 0 0 . 00 8 .60 0.00 14930 .54 18 . 00 24 .00 140 . 00 9 . :0 0 . 00 8 .60 ' 0 . 00 15648 .81 18 . 00 24 . 00 140 . 00 9 . 10 0 .00 8 . 60 0 .00 16340 .03 18 . 00 24 . 00 140 . 001 10 . 60 0 . 00 8 .60 0 .00 17007.19 18 . 00 24 .00 140 . 001 10. 0 0 . 00 8 .60 0. 00 17652 .76 18 . 00 24. 00 140 . 00 10. ,0 0 .00 8 .60 0.00 18278 . 82 18 .00 24 .00 140 . 00 10 . : 0 0 . 00 8 .60 0 .00 18887.12 18 . 00 24 .00 140 .00 I.0. . 0 0 . 00 8 .60 0 .00 19479 .17 18 . 00 24 . 00 140 . 00 0 0 . 00 8 .60 0 . 00 20056 .28 18 .00 24 . 00 140 .00 0. •0 0 .00 8 .60 0 .00 20619 .57 18 . 00 24 .00 140 . 00 10 . 0 0 . 00 8 .60 , 0 .00 21170 .04 18 . 00 24 . 00 140 .00 10 . :0 0 . 00 8 .60 , 0 . 00 21708 .59 18 . 00 24 . 00 140 .00 10. :0 0 .00 8 .60 0 .00 22235. 99 18 . 00 24 . 00 140 . 0 11. 60 0 . 010 8 .60 0 . 00 22752 . 93 18 . 00 24 .00 140 .0 11. 10 0 . 0I0 8 . 60 , 0. 00 23260 . 07 18 . 00 24 . 00 140 . 00 11 . ' 0 0 . 00 8 .60 0 . 00 23757. 95 18 . 00 24 . 00 140 . 00 11 . :0 0 . 0I0 8 .60i 0 .00 24247.10 18 . 00 24 .00 140 . 0 11. . 0 0 . 00 8 .60 0. 00 24727 .98 18 . 00 24 .00 140 .0 1 11. .0 0 .00 8 .60 , 0 .00 25201. 03 18 .00 24 .00 140 .00 11. .0 0 . 00 8.60 0 .00 25666 .63 18 . 00 24 .00 140 .00 11. 0 0 .00 8 . 60 0. 00 26125 .14 18 .00 24 . 00 140 .00 11. :0 0 . 00 8 .60 0 .00 26576 . 90 18 . 00. 24 . 00 140 . 00 1 11. :0 0 . 00 8 . 60 0 .00 27022 .21 18 . 00 24 .00 140 .0 12 . 10 0 .00 8 .60 ' 0 . 00 27461.36 18 . 00 24 . 00 140 . 0 12 .60 0 . 00 8 .6b 0 . 00 27894 .60 18 . 00 24 .00 140 . 00 12 .+0 0 . 00 8 . 60 0 . 00 28322 . 18 18 . 00 24 . 00 140 .00 12 .c0 0 . 00 8 .610 0. 00 28744 .34 18 . 00 24 . 00 140 . 00 12 . . 0 0 . 00 8 . 6I0 140 . 000 .00 29161 .27 18 . 00 24 . 00 12 . 50 0 . 00 8 .610 0 .00 29573 . 19 18 . 00 24 . 00 140 .00 Open Channel FlovJ Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 I 1I i Page 3 of 3 VARIABLE COMPUTED Elev. Pressure E1evl. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2; @ 2 gpm in ft ft psi ft psi 12 . 60 0 . 00 8 . 60 0 . 00 29980 .28 18 . 00 24 . 00 140 . 00 12.70 0 .00 8 .60 0 .00 30382 .72 18 . 00 24 . 00 140 .00 12 .80 0 . 00 8 .60 0 . 00 30780 .66 18 .00 24 .00 140 .00 12 .90 0 . 00 8 .60 0 .00 31174 .27 18 .00 24 . 00 140 . 00 13 .00 0 .00 8 . 60 0 .00 31563 .69 18 . 00 24 . 00 140 .00 13 .10 0 .00 8 .6';0 0 . 00 31949 . 06 18 . 00 24 . 00 140 . 00 13 .20 0 . 00 8 . 60 0 . 00 32330 .51 18 . 00 24 . 00 140 . 00 13 .30 0 .00 8 .60 0 . 00 32708 .17 18 . 00 24 . 00 140 . 00 13 .40 0 . 00 8 .60 0. 00 33082 .14 18 . 00 24 .00 140 . 00 13 .50 0 .00 8 .6,0 0 . 00 33452 .55 18 .00 24 . 00 140 .00 13 .60 0 . 00 8 . 60 0.00 33819 .50 18 .00 24.00 140 .00 13 .70 0 .00 8 .60 0 . 00 34183 .08 18 . 00 24 .00 140 .00 13 .80 0 . 00 8 . 60 0 . 00 34543 .41 18 .00 24 . 00 140 . 00 13 .90 0 .00 8 .60 0 . 00 34900 .55 18 . 00 24 .00 140 .00 14.00 0 . 00 8 . 60 0 .00 35254 .62 18 .00 24 . 00 140 .00 14 .10 0 .00 8 .60 0 . 00 35605 .67 . 18 .00 24 . 00 140.00 14 .20 0 . 00 8 .60 0 . 00 35953 . 81 18 .00 24 .00 140 . 00 14 .30 0 .00 8 .60 0 . 00 36299 .09 18 . 00 24 . 00 140 .00 14 .40 0 . 00 8 .60 0 . 00 36641.60 18 . 00 24.00 140 . 00 1 .50 0 .00 8 .60 0 .00 36981.41 18 . 00 24 . 00 140 .00 14 .60 0 . 00 8 .60 0 . 00 37318 .57 18 .00 24 .00 140 .00 14 .70 0 . 00 8 . 60 0 . 00 37653 . 16 18 . 00 24 .00 140 .00 14 . 80 0 . 00 8 .60 0 . 00 37985 .24 18 . 00 24 . 00 140 . 00 14 . 90 0 . 00 8 . 60 0 . 00 38314 .86 18 . 00 . 24 . 00 140 .00 15 . 00 0 . 00 8 .60 0 . 00 38642 . 08 18 .00 24 . 00 140 .00 15 . 10 0 . 00 8 . 60 0 . 00 38966 . 96 18 . 00 24 .00 140 . 00 15 .20 0 . 00 8 . 60 0 .00 39289 .55 18 . 00 24 . 00 140 . 00 15 .30 0 .00 8 . 60 0 . 00 39609 . 90 . 18 .00 24 . 00 140 .00 15 .40 0 .00 8 .60 0 .00 39928 . 06 18 . 00 . 24 .00 140 .00 15.50 0 .00 8 .60 0. 00 40244 .07 18. 00 24 .00 140 .00 15. 60 0 . 00 8 .60 0 .00 40557. 98 18 . 00 24 . 00 140 .00 15 .70 0 .00 8 .60 0 . 00 . 40869. 83 18 .00 24 . 00 140.00 15 .80 0 . 00 8 .60 0 .00 41179 .67 18 .00 24 . 00 140 .00 15 .90 0 .00 8 .60 0 . 00 41487.54 18 . 00 24 .00 140. 00 1 ! 16 . 00 0 . 00 8 .60 0 .00 41793 .47 18 . 00 24 . 00 140 .00 16 .10 0 .00 8 .60 0 . 00 42097.51 18 . 00 24 . 00 140 .00 i Open Channel Flow Module, Version 3 .11 (c) Haestad Methods,, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 i I i I Page 1 of 3 L Pressure Pipe Analysis & Design . Circular Pipe Worksheet ame: basin ' 3 pre-dev 36" mescriptian: Basin 3 Outlet 36" DIP Solve For Discharge Given Consitant Data; Pressure @ 1 0 . 00 Elevation @2 8 .60 Pressure @ 1 0 .00 Discharge 46869 .55 iameter 36 .00 Length 44 . 00 Hazen-Williams C 130 .0000 Varia•le Input Data Minimum Maximum Increment By Elev-tion @ 1 8 .60 16. 00 0 ..10 BASIN 3 : 3( DIP OUTLET FROM cor r o1 S TRJLT vita, OISc.NARGE To SPRINc3Roo S CREEt"-, CS-V 0eAko, NCeq D SLhargcvv1k- E Mct\ T Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 i I Page 2 of 3 VARIABLE COMPUTED Elev. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2I @ 2 gpm in ft ft psi ft 1 psi Unable to compute this instance. 8 .70 0 .00 8 .60 0 .00 16947. 17 36 . 00 44 . 00 130 . 00 8 .80 0 . 00 8 .60 0 .00 24640.72 36 . 00 44 . 00 130 . 00 8 .90 0 . 00 8 .60 0 .00 30672 . 04 36 . 00 44 . 00 130 . 00 9. 00 0 . 00 8 . 60 0 . 00 35826. 93 36 . 00 44 . 00 130 . 00 9 .10 0 . 00 8 . 60 0 . 00 40414 . 85 36 . 00 44 . 00 130 . 00 9.20 0 .00 8 . 60 0 . 00 44596.30 36 .00 44 . 00 130 . 00 9.30 0 .00 8 .60 0 . 00 48467.44 36 . 00 44 . 00 130 . 00 9 .40 0 . 00 8 .60 0 . 00 52091.37 36 .00 44 . 00 130 . 00 9.50 0 .00 8.60 0 . 00 55512.16 36 . 00 44 . 00 130 .00 9 .60 0.00 8 .60 0 . 00 58762 .08 36 .00 44 . 00 130 . 00 9 .70 0 .00 8 .60 0 . 00 61865. 60 36 . 00 44 .00 130 . 00 9.80 0 .00 8 .60 0 .00 64841. 80 36 . 00 44 . 00 130 . 00 9 .90 0 . 00 8 . 6,0 0 . 00 67705. 91 36 . 00 44 . 00 130 . 00 10.00 0 .00 8 .60 0 . 00 70470 .33 36 .00 44 .00 130 . 00 10 .10 0 . 00 8 .60 0 .00 73145 .31 36 . 00 44 . 00 130 .00 10 .20 0 .00 8 .60 0 . 00 75739 .42 36 .00 44 .00 130 . 00 10 .30 0 . 00 8 .60 0 .00 78259 . 96 36 . 00 44 . 00 130 . 00 1.0.40 0 . 00 8 . 60 0 . 00 80713 .16 36 . 00 44 . 00 130 .00 50 0 . 00 8 .60 0 . 00 83104 .42 36 .00 44 . 00 130 . 00 0.60 0 . 00 8.6'0 0 .00 85438 .45 36 . 00 44 . 00 130 . 00 10.70 0 .00 8 .60 0 . 00 87719 .39 36 . 00 44 . 00 130 . 00 10 .80 0 . 00 8 .60 0 . 00 89950 . 88 36 . 00 44 . 00 130 . 00 10. 90 0 . 00 8 . 60 0 .00 92136 . 18 36 .00 44 . 00 130 . 00 1 ! 11 . 00 0 . 00 8 .60 0 . 00 94278 .19 36 . 00 44 . 00 130 . 00 11. 10 0 . 00 8 .60 0 . 00 96379 .53 36 . 00 44 . 00 130 . 00 11.20 0 .00 8 .60 0 . 00 98442 .54 36 . 00 44 . 00 130 . 00 11.30 0 . 00 8 .60 0 . 00 100469 .36 36 . 00 44 . 00 130 . 00 11.40 0 .00 8 .60 0. 00 102461.93 36 .00 44 . 00 130 . 00 11.50 0 . 00 8 .60 0 . 00 104422 . 02 36 . 00 44 .00 130 . 00 11.60 0 .00 8 .60 0 .00 106351.26 36 .00 44 . 00 130 .00 11.70 0 . 00 8 .60 0. 00 108251.14 36 . 00 44 . 00 130 . 00 11.80 0 . 00 8 .60 0 . 00 110123 .03 36 . 00 44 . 00 130 . 00 11. 90 0 . 00 8 . 60 0 . 00 111968 .20 36 . 00 44 . 00 130 . 00 12 . 00 0 . 00 8 .60 0 . 00 113787.83 36 . 00 44 .00 130 . 00 - ' ' 12 .10 0 .00 8 .60 0 . 00 115582 . 99 36 . 00 44 . 00 130 . 00 12 .20 0 . 00 8 .60 0 . 00 117354 .71 36 . 00 44 . 00 130 . 00 12 .30 0 . 00 8 .60 0 . 00 119103 . 94 36 . 00 44 .00 130 . 00 12 .40 0 . 00 8 . 60 0 .00 120831.54 36 . 00 44 . 00 130 . 00 12 .50 0 . 00 8 .60 0 . 00 122538 . 36 36 . 00 44 .00 130 . 00 Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, iInc. * 37 Brookside Rd * Waterbury, Ct 06708 Page 3 of 3 h 1. J• 'IABLE i COMPUTED l El:v. Pressure Elev. : Pressure Discharge Diameter Length Hazen-W @1 @1 @2 ' .@2 gpm in ft f• psir ft psi 1. 12 . : 0 0 . 00 8 . 60 0 . 00 124225. 16 36 . 00 44 .00 130 . 00 12 . 0 0 . 00 8 . 60 0 . 00 125892 . 68 36 . 00 44 . 00 130 . 0 12 . : 0 0 .00 8 .60 , 0 .00 127541.58 36 . 00 44 . 00 130: 0 1. 12 . '0 0 .00 8 . 60 ; 0 . 00 129172 . 52 , 36 . 00 44 .00 130 . 0 13 . 10 0 . 00 8 . 60 , 0 . 00 130786 .11. 36 . 00 44 . 00 130 . 00 13 . 0 0 . 0c 8 . 60 ' 0 . 00 132382 . 91 36 . 00 ' 44. 00 130 . 0 6 13 ._.0 0 . 0 8 .60 0 .00 133963 .48 36 . 00 44 . 00 130 . 00 13 . 0 0 . 00 8 .60 , 0. 00 135528 .31 36 . 00 44 . 0.0 130 . 0 6 13 . ' 0 0 . 00 8 .60 ' 0 . 00 137077. 90 . 36 . 00 44 . 00 130 . 0013 . ' 0 0 .0Q 8 . 60 0.00 138612 .71 36 . 00 44 .00 130.. 00 13 . : 0 0 .00 8 . 60 ' 0 . 00 140133 .18 36 . 00 44 .00 130 . 010 13 . '0 0 .00 8 .60 ' 0.00 141639 . 73 36 . 00 44 . 00 130 . 0 0 13 . :0 0 . 00 8 .60 , 0 .00 143132 .74 36 . 00 44 .00 130 . 00 13 . ' 0 0 . 00 8 . 60 0. 00 144612 . 61 36 . 00 44 .00 130 .010 14. 00 0 . 00 8 .60 , 0 . 00 146079 . 68 36 . 00 44 . 00 130 . 00 14. 0 0 .00 8 .60 1 0 .00 147534 .31 36 . 00 44 . 00 130 . 00 14 . : 0 0 . 00 8 .60 0 . 00 148976. 83 36 . 00 44 .00 130 .00 14 . 0 0 . 00 8 . 60 . 0. 00 150407 .54 36 . 00 44 .00 130 . 0 14. ' 0 0 . 0 8 . 60 0 . 00 151826 .75 36 . 00 44.00 130 . 00 I . '0 0 . 0 8 .60 0 . 00 153234 . 75 36 . 00 44 . 00 130 . 00 4 . ..0 0 . 00 8 . 60 0 .00 154631. 82 36 . 00 44 .00 130 . 00 14 . '0 0 . 00 8 . 60 0 . 00 156018 .21 36 . 00 44 . 00 130 .00 14 . :0 0 . 00 8 . 60 : 0 . 00 157394 . 19 36 . 00 44 .00 130 . 00 14 . '-0 0 . 00 8 .60 ' 0 .00 158760 . 00 36 . 00 44 . 00 130 . 00i 15 . 00 0 . 00 8 . 60 . 0 . 00 160115 . 87 36 . 00 44 . 00 130 . 00 15. 0 0 . 00 8 . 60 : 0 . 00 161462 . 02 36 . 00 44 .00 130 . 0I0 15 . '0 0 .00 8 .60 , 0 .00 162798 . 69 36 . 00 44 .00 130 . 00 15 . . 0 0 . 00 8 .60 ' 0 . 00 164126 . 07 36 . 00 44 . 00 130 . 0I0 15. ' 0 0 . 00 8 .60 : 0. 00 165444 .37 36 .00 44 . 00 130 . 0I0 15. '.0 0 . 00 8 .60 ; 0 .00 166753 . 78 36 . 00 44 .00 130 .00 15 . . 0 0 .00 8 .60 . 0 . 00 168054 .49 36 . 00 44 .00 130 .00 15. ' 0 0. 00 8 .69 : 0 . 00 169346 , 68 36 .00 44.00 130 . 00, 15 . :0 0 . 00 8 . 60i 0 .00 170630 . 53 36 . 00 44 .00 130 . 00 15. :0 0 . 00 8 . 60 0 . 00 171906 . 19 36 . 00 44 .00 130 .00 16 . 40 0 . 00 8 .60 0 . 00 173173 . 85 36 . 00 44 . 00 130 .00 16 . 0 0 . 0 8 .66 0 . 00 . 174433 . 65 36 . 00 44 . 00 130 . 00i Open Ch nnel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 9/10/98 10 :23 :31 am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BSN A,DELTA ROUTED TO SPRINGBRK LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESCRIPTION cfs) (cfs) --id- --id- c-STAGE> id (cfs) VOL (cf) WQ, POST BASIN /i 0.00 0.22 DELTA PSTA 7.80 1 0.00 20911.71 cf 2YR, POST BASIN A 0.00 5.33 DELTA PSTA 8.71 2 5.29 97980.51 cf 5YR, POST BASIN A 0.00 7.33 DELTA PSTA 8.75 3 7.31 2 ac-ft 10YR, POST BASIN A 0.00 10.36 DELTA PSTA 8.81 4 10.32 2 ac-ft 25YR, POST BASIN A 0.00 13.73 DELTA PSTA 8.89 5 13.72 3 ac-ft 50YR, POST BASIN A 0.00 14.08 DELTA PSTA 8.89 6 14.05 3 ac-ft 100YR, POST BASIN A 0.00 18.13 DELTA PSTA 8.97 7 17.85 3 ac-ft I I t i II D File Input Hydrograph Storage Discharge LPool Proj : SWMP eeee"8&888888888888868888,68Routing Comparison Tableeeeeeeeeeeeeeeeeeeee 'eeeeee ; MATCH INFLOW STO DIS PEAK PEAK OUT iESCRIPTION PEAK! PEAK No.No. STG OUT HYD 0 WQ, •OST BASINB-3 0 . 00 0 .26 PONDC COMBO2 10 . 00 0 .26 1 2YR, POST BAST B-3 0 . 00 1 .26 PONDC COMBO2 11 . 31 0 .38 2 0 SYR, POST BASIN' B-3 0 . 00 1. 64 PONDC COMBO2 11.47 0 . 52 3 j 0 10YR, POST BASIN B-3 0 . 00 2 . 12 PONDC COMBO2 11 . 66 . 0 . 68 4 0 2YR, POST BASIN B-3 0 . 00 2 . 62 PONDC COMBO2 11. 88 0 . 87 5 0 50YR, POST BASIN B-3 0 . 00 2 . 67 PONDC COMBO2 11 . 90 0 . 90 6 0 1100Y- , POST BASIN B-3 0 . 00 3 . 13 PONDC COMBO2 12 . 10 1 . 04 7 0 0 0 0 0 0 7 Done< Press any key to exit', Aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee=eeeeeef enu: Perform Level pool computations using input table instructions Pos- - OEvEL.0 P MEI Sv RFiNLE caper MAn)AGE MI-'JV PR,ySG'-T BASIN $3 ROv-U=O -Nat\VolA Pon 0 a` epat -rfw..w KrE tt — c1,15 ii 9/10/98 7 :24 :43 . am Sverdrup Civil Inc page THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BASIN B-3, ' ROUTED THRU POND "C STAGE STORAGE TABLE CUSTOM STORAGE ID No. PONDC Description: POND "C" STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (,ft.) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 11.00 0.0000 0.0000 11.80 5293 0.1215 12.60 11559 0.2654 13.40 18761 0.4307 11.10 629.19 0.0144 11.90 6009 0.1379 12.70 12424 0.2852 13.50 19697 0.4522 11.20 1258 0.0289 12.00 6724 0.1544 12.80 13288 0.3051 13.60 20707 0.4754 11.30 1888 0.0433 12.10 7518 0.1726 12.90 14152 0.3249 13.70 21716 0.4985 11.40 2517 0.0578 12.20 8313 0.1908 13.00 15017 0.3447 13.80 22725 0.5217 11.50 3146 0.0722 12.30 9107 0.2091 13.10 15953 0.3662 13.90 23735 0.5449 11.60 3862 0.0887 12.40 9901 0.2273 13.20 16889 0.3877 14.00 24744 0.5680 11.70 4577 0.1051 12.50 10695 0.2455 13.30 17825 0.4092 I II I I ' i I 9/10/98 7 :24 :43 , a•m Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BASIN B-3, ROUTED THRU POND "C STAGE DISCHARGE TABLE COMBINATION DISCHARGE ID No. COMB02 Description: POND "C" COMBO STRUCTURE Structure: PONDC2 Structure: Structure: RISER Structure: Structure : I STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs I 10.00 0.0000 1080 0.2995 11.60 0.6469 12.40 1.2161 I 10.10 0.1059 10L90 0.3177 11.70 0.7101 12.50 1.2671 10.20 O.1I498 11.00 0.3349 11.80 0.7650 12.60 1.6236 10.30 0.1834 11.10 0.3512 11.90 0.8955 12:70 2.2332 10.40 0.2118 1120 0.3669 12.00 0.9747 12.75 2.6021 10.50 0.2368 11.30 0.3818 12.10 1.0431 10.60 0.2794 11.40 0.3963 12.20 1.1050 10.70 0.2802 11!50 0.5680 12.30 1.1623 I p page 3SverdruCivilInc9/10/98 7 :24 :43 am THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BASIN B-3, ROUTED THRU POND "C STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. PONDC2 Description: POND "C" DISCHARGE STRUCTURE Outlet Elev: 10 . 00 Elev: 8 .25 ft Orifice Diameter: 3 . 5130 in. Elev: 11.40 ft Orifice 2 Diameter: 4 . 2890 in. Elev: 11. 80 ftl Orifice 3 Diameter: 3 . 0700 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs 10.00 0.0000 10.00 0.0000 10.00 0.0000 10.00 0.0000 i 1 I I 9/10/981 7 :24 :431am Sverdrup Civil Inc page 4 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BASIN B-3, ROUTED THRU POND "C STAGE DISCHARGE TABLE RISER DISCHARGE ID No. RISER Descripion: POND"C" RISER Riser Diameter (in) : 12 . 00 elev: 12 . 50 ft Weir Coefficient . .' . : 9 . 739 height : 12 . 75 ft Orif Coefficient . 3 . 782 increm: 0 . 10 ft STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) cfis ft) ---cfs ft) ---cfs ft) ---cfs i I 12.50 0.01000 12.60 0.3080 12.75 1.2174 12.75 1.2174 12.50 0.0000 1200 0.8711 i I I j I 9/10/98 7 :24 :44. am Sverdrup Civil Inc page 5 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BASIN B-3, ROUTED THRU POND "C LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE jl DESCRIPTION cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf) WQ, POST BASIN B-3 0.00 0.26 PONDC COMB02 10.00 1 0.26 0.00 cf 2YR, POST BASIN B-3 0.00 1.26 PONDC COMB02 11.31 2 0.38 1946.03 cf 5YR, POST BASIN B-3 0.00 1.64 PONDC COMB02 11.47 3 0.52 2983.94 cf 10YR, POST BASIN B-3 0.00 2.12 PONDC COMB02 11.66 4 0.68 4281.20 cf 25YR, POST BASIN B-3 0.00 2.62 PONDC COMB02 11.88 5 0.87 5858.61 cf 50YR, POST BASIN B-3 0.00 2.67 PONDC COMB02 11.90 6 0.90 6007.94 cf 100YR,POST BASIN B-3 0.00 3.13 PONDC COMB02 12.10 7 1.04 7484.70 cf I I I D File Input Hydrograph Storage Discharge LPool Proj SWMP 5eeeeeeeeeeeeeeeeeeeeeeeeeeRouting Comparison Tableeeeeeeeeeeeeeeeeeeee"eeeeeep MATCH. INFLOW STO DIS PEAK PEAK OUT DESCRIPTIOI PEAK PEAK No.No. STG OUT HYD o WQ, OST BASIN B 0 . 06 0 .44 4C 4C 7 .27 0 . 00 8 2YR, POST BASIN B 0 . 00 3.. 37 4C 4C 9 . 12 1 .59 9 0 SYR, POST BASIN B 0 . 00 4 .45 4C 4C 9 . 14 2 . 90 10 10YR POST BASIN B 0 . 00 5 . 87 4C 4C 9 .16 4 .52 11 i 2YR POST BASIN B 0 . 00 7 .48 4C 4C 9 .20 7 .48 12 0 50YR POST BASIN B 0 . 00 7 . 64 4C 4C 9 . 19 7 .63 13 0 100Y , POST BASIN B 0 . 06 9 . 05 4C 4C 9 .21 9 . 05 14 0 0 0 0 Done< Press any key to exit 0 Aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef 7,enu: Perform Level pool computations using input table instructions Sv fZFAce W AT E tL MAN)AGE M BNi PRo-SecT sINs e- , a-2 „A- 4^3 R.0V'TEfD 1-1+Ro V G1- i I Zae,'ee.E iRPte.t., To SpRiNIC, ocA, CREAK p_ SEAR "TP.‘c we‘-rea, = 61,15 I i1 9/10/98 10 :31 :26 am Sverdrup Civil Inc page 1 - THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BASIN B, ROUTED TO SPRINGBROOK STAGE STORAGE TABLE i CUSTOM STORAGE ID No. 4C Description: POND4C STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf•--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 6.00 0.0000 0.0000 8.30 25325 0.5814 10.60 63992 1.4691 12.90 150929 3.4649 6.10 952.40 0.0219 8.40 26627 0.6113 10.70 66270 1.5214 13.00 155909 3.5792 6.20 1905 0.0437 8.50 27929 0.6412 10.80 68549 1.5737 13.10 164079 3.7667 6.30 2857 0.0656 8.60 29231 0.6711 10.90 70827 1.6260 13.20 172248 3.9543 6.40 3810 0.0875 8.70 30533 0.7010 11.00 73105 1.6783 13.30 180418 4.1418 6.50 4762 0.1093 8.80 31836 0.7308 11.10 76405 1.7540 13.40 188588 4.3294 6.60 5714 0.1312 8.90 33138 0.7607 11.20 79706 1.8298 13.50 196758 4.5169 6.70 6667 0.1530 9.00 34440 0.7906 11.30 83006 1.9056 13.60 204927 4.7045 6.80 7619 0.1749 •9.10 36028 0.8271 11.40 86307 1.9813 13.70 213097 4.8920 6.90 8572 0.1968 99.20 37617 0.8636 11.50 89607 2.0571 13.80 221267 5.0796 1 7.00 9524 0.2186 9.30 39205 0.9000 11.60 92907 2.1329 13.90 229436 5.2671 7.10 10713 0.2459 19.40 40793 0.9365 11.70 96208 2.2086 14.00 237606 5.4547 7.20 11903 0.2733 19.50 42382 0.9729 11.80 99508 2.2844 14.10 252061 5.7865 7.30 13092 0.3006 9.60 43970 1.0094 11.90 102809 2.3602 14.20 266517 6.1184 7.40 14282 0.3279 9.70 45558 1.0459 12.00 106109 2.4359 14.30 280972 6.4502 7.50 15471 0.3552 9.80 47146 1.0823 12.10 111089 2.5503 14.40 295427 6.7821 7.60 16660 0.3825 9.90 48735 1.1188 12.20 116069 2.6646 14.50 309883 7.1139 7.70 17850 0.4098 10.00 50323 1.1553 12.30 121049 2.7789 14.60 324338 7.4458 7.80 19039 0.4371 10.10 52601 1.2076 12.40 126029 2.8932 14.70 338793 7.7776 7.90 20229 0.4644 10.20 54879 1.2599 12.50 131009 3.0076 14.80 353248 8.1095 8.00 21418 0.4917 10.30 57158 1.3122 12.60 135989 3.1219 14.90 367704 8.4413 8.10 22720 0.5216 10.40 59436 1.3645 12.70 140969 3.2362 8.20 24022 0.5515 10.50 61714 1.4168 12.80 145949 3.3505 1 ' I i I III 9/10/98 10 :31 :26 am Sverdrup Civil Inc page 2 THE BOEING COMPANY SURFACE WATERMANAGEMENT PROJECT POST-DEV BASIN B, ROUTED TO SPRINGBROOK I STAGE DISCHARGE TABLE I CUSTOM DISCHARGE ID No. 4C Description: POND4C STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft) ---cfs ft) ---cfs ft) ---cfs ft) ---cfs 9.15 0.0000 10.95 136.53 12.75 198.59 14.55 247.32 9.25 16.126 11.05 140.61 12.85 201.57 14.65 249.75 9.35 32.251 111.15 144.44 12.95 204.55 14.75 252.18 9.45 48.377 11.25 148.27 13.05 207.44 14.85 254.61 9.55 59.910 11.35 152.09 13.15 210.25 14.95 257.04 9.65 66.850 11.45 155.92 13.25 213.06 15.05 259.43 9.75 73.790 111.55 159.56 13.35 215.87 15.15 261.77 9.85 80.730 11.65 163.03 13.45 218.68 15.25 264.11 9.95 87.670 11.75 166.49 13.55 221.41 15.35 266.45 10.05 93.726 11.85 169.95 13.65 224.08 15.45 268.79 10.15 98.898 111.95 173.42 13.75 226.74 15.55 271.09 10.25 104.07 121.05 176.75 13.85 229.40 15.65 273.34 10.35 1091.24 12.15 179.94 13.95 232.07 15.75 275.60 10.45 114.41 12,.25 183.14 14.05 234.67 15.85 277.86 10.55 119.17 12.35 186.34 14.15 237.21 15.95 280.11 10.65 123.51 12.45 189.53 14.25 239.75 16.05 281.24 10.75 127.85 12.55 192.62 14.35 242.29 10.85 132.19 12.65 195.60 14.45 244.83 i I Page 1 of 3 Pressure Pipe Analysis & Design Circular Pipe i Worksheet Name: Practice Track Description: Practice Track Outlet I Solve For Discharge ' Given Constant Data; Pressure @ , 1 0 . 00 Elevation @ 2 9 .15 — 2'((t TA11-`^'aMER At SPRI.JG 8RootS (REEY Pressure @11 0 . 00 Discharge 0 . 00 Diameter 36 . 00 Length 45 . 00 Hazen-Williams C 100 . 0000 Variable Input Data Minimum Maximum Increment By Elevation @ 1 9 . 00 16 . 00 0 . 10 i e•1:61n' 6 :i Q15C. ARGC 1203CTiNG CvRVE CAL Cvi.ATIONS .o(Z. Sue- 8PrSiN5 el.\ B-2 a 4,- 6-3 "t'H Rov6H J f lutc 11 C E "C.Prc.`f, 'To SPruwg, 642.01*- cAaeY, 1 I eJC ,.0 P ME 0-1.S u RFAL.v. 1,.wtg?ER MP J 4GENtENT pos-c - 9 PnoZEL Open Channel Flow Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 1 Page 2 of 3 I V IABLE COMPUTED Elev. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2@ 2 gpm in ft f1 psi ft psi 9 .0 0 . 00 9 . 15 0 . 00 -16031 .45 36 . 00 45 . 00 100 . 00 9.10 0 . 00 9 .15 0 . 00 -8857 . 83 36 . 00 45 . 00 100 . 00 9 .20 0 . 00 9 . 15 0 . 00 8857 . 83 36 . 00 45 . 00 100 . 00 9 . 0 0 . 00 9 . 15 0 . 00 16031 .45 36 . 00 45 . 00 100 . 00 19 .40 0 . 00 9 . 15 0 . 00 21123 . 76 36 . 00 45 . 00 100 . 00 9 .50 0 . 00 9 . 15 0 . 00 25332 . 63 36 . 00 45 . 00 100 . 00 9 . 60 0 . 00 9 . 15 0 . 00 29014 . 71 36 . 00 45 . 00 100 . 00 9 .70 0 . 00 9 . 15 0 . 00 32335 .48 36 . 00 45 . 00 100 . 00, 9 . q0 0 . 00 9 . 15 0 . 00 35388 . 06 36 . 00 45 . 00 100 . 00 19 . 0 0 . 00 9 . 15 0 . 00 38231 . 08 36 . 00 45 . 00 100 . 00 10 . c0 0 . 00 9 . 15 0 . 00 40904 .37 36 . 00 45 . 00 100 . 00 10 .10 0 . 00 9 .15 0 . 00 43436 .44 36 . 00 45 . 00 100 . 00 10 .20 0 . 00 9 . 15 0 . 00 45848 . 56 36 . 00 45 . 00 100 . 00 10 .30 0 . 00 9 . 15 0 . 00 48157.10 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 . 15 0 . 00 50374 . 98 36 . 00 45 . 00 100 . 00 10 .50 0 . 00 9 . 15 0 . 00 52512 . 63 36 . 00 45 . 00 100 . 00 10 . 0 0 . 00 9 . 15 0 . 00 54578 .58 36 . 00 45 . 00 100 . 00 10 . 70 0 . 00 9 .15 0 . 00 56579 . 96 36 . 00 45 . 00 100 . 001 0 .80 0 . 00 9 .15 0 . 00 58522 . 77 36 . 00 45 . 00 100 . 00 0 . 90 0 . 00 9 . 15 0 . 00 60412 . 12 36 . 00 45 . 00 100 . 00 11 . Q0 0 . 00 9 . 15 0 . 00 62252 .42 36 . 00 45 . 00 100 . 00 11 . 10 0 . 00 9 . 15 0 . 00 64047 . 50 36 . 00 45 . 00 100 . 00 11. 0 0 . 00 9 . 15 0 . 00 65800 . 71 36 . 00 45 . 00 100 . 00 11. 0 0 . 00 9 . 15 0 . 00 67515 . 00 36 . 00 45 . 00 100 . 00, 11 . 0 0 . 00 9 . 15 0 . 00 69192 . 99 36 . 00 45 . 00 100 . 001 11 . 50 0 . 00 9 . 15 0 . 00 70837. 00 36 . 00 45 . 00 100 . 00 11 . 60 0 . 00 9 . 15 0 . 00 72449 . 13 36 . 00 45 . 00 100 . 00 11 . '0 0 . 00 9 . 15 0 . 00 74031. 27 36 . 00 45 . 00 100 . 00 11 . 80 0 . 00 9 . 15 0 . 00 75585 . 12 36 . 00 45 . 00 100 . 00 11 . 0 0 . 00 9 . 15 0 . 00 77112 . 21 36 . 00 45 . 00 100 . 00 12 . 0 0 . 00 9 . 15 0 . 00 78613 . 97 36 . 00 45 . 00 100 . 00 12 . 10 0 . 00 9 . 15 0 . 00 80091 . 68 36 . 00 45 . 00 100 . 00 12 .20 0 . 00 9 . 15 0 . 00 81546 .52 36 . 00 45 . 00 100 . 00 12 . 0 0 . 00 9 . 15 0 . 00 82979 . 58 36 . 00 45 . 00 100 . 00 12 .40 0 . 00 9 . 15 0 . 00 84391. 85 36 . 00 45 . 00 100 . 00 12 . 0 0 . 00 9 . 15 0 . 00 85784 .28 36 . 00 45 . 00 100 . 00 12 . g0 0 . 09 9 . 15 0 . 00 87157 . 71 36 . 00 45 . 00 100 . 00 12 . I0 0 . 00 9 . 15 0 . 00 88512 . 95 36 . 00 45 . 00 100 . 00 12 . 10 0 . 00 9 .15 0 . 00 89850 . 74 36 .00 45 . 00 100 . 00 12 . '0 0 . 00 9 . 15 0 . 00 91171 . 77 36 . 00 45 . 00 100 . 00 I i Open Channel Flow Module, Version 3 . 11 (c) Haestad1Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 I i Page 3 of 3 VARIABLE i COMPUTED Elev. Pressure Elev. Pressure Discharge Diameter Length Hazen-W C @ 1 @ 1 @ 2 @ 2 gpm in ft ft psi ft 1 psi I 13 . 00 0 . 00 9.15 0 . 00 92476 . 70 36 . 00 45 . 00 100 . 00 13 . 10 0 . 00 9 .15 0 . 00 93766 . 12 36 . 00 45 . 00 100 . 00 13 .20 0 . 00 9 . 15 0 . 00 95040 . 61 36 . 00 45 . 00 100 . 00 13 .30 0 . 00 9 . 15 0 . 00 96300 .71 36 . 00 45 . 00 100 . 00 13 .40 0 . 00 9 .15 0 . 00 97546 . 92 36 . 00 45 . 00 100 . 00 13 .50 0 . 00 9 .15 0 . 00 98779 . 70 36 . 00 45 . 00 100 . 00 13 . 60 0 . 00 9 .15 0 . 00 99999 .52 36 . 00 45 . 00 100 . 00 13 . 70 0 . 00 9 .15 0 . 00 101206 .79 36 . 00 45 . 00 100 . 00 13 . 80 0 .00 9.15 0 . 00 102401. 92 36 . 00 45 . 00 100 . 00 13 . 90 0 . 00 9 .15 0 . 00 103585 .29 36 . 00 45 . 00 100 . 00 14 . 00 0 . 00 9 .15 0 . 00 104757 .24 36 . 00 45 . 00 100 .00 14 .10 0 . 00 9 .15 0 . 00 105918 .13 36 . 00 45 . 00 100 . 00 14 .20 0 . 00 9.15 0 . 00 107068 .29 36 . 00 45 . 00 100 . 00 14 .30 0 . 00 9 .15 0 . 00 108208 . 01 36 . 00 45 . 00 100 . 00 14 .40 0 . 00 9 . 15 0 . 00 109337. 60 36 . 00 45 . 00 100 . 00 14 . 50 0 . 00 9 .15 0 . 00 110457.33 36 . 00 45 . 00 100 . 00 i 14 .60 0 . 00 9 .15 0 . 00 111567 .48 36 . 00 45 . 00 100 . 00 1 14 .70 0 . 00 9 .15 0 . 00 112668 .30 36 . 00 45. 00 100 . 00 4 . 80 0 . 00 9 . 15 0 . 00 113760 . 03 36 . 00 45 . 00 100 .,00 4 . 90 0 . 00 9 .15 0 . 00 114842 . 90 36 . 00 45 . 00 100 . 00 15. 00 0 . 00 9.15 0 . 00 115917 .15 36 . 00 45 . 00 .100 . 00 15 . 10 0 . 00 9 .15 0 . 00 116982 . 98 36 . 00 45 . 00 100 . 00 15 .20 0 . 00 9 .15 0 . 00 118040 . 60 36 . 00 45 . 00 100 . 00 15 .30 0 . 00 9 . 15 0 . 00 119090 .22 36 . 00 45 . 00 100 . 00 15 .40 0 . 00 9 . 15 0 . 00 120132 . 01 36 . 00 45 . 00 100 . 00 15 . 50 0 . 00 9 .15 0 . 00 121166 . 16 36 . 00 45 . 00 100 . 00 I 15 . 60 0 . 00 9 . 15 0 . 00 122192 . 84 36 . 00 45 . 00 100 . 00 15 . 70 0 . 00 9 .15 0 . 00 123212 .23 36 . 00 45 . 00 100 . 00 15 . 80 0 . 00 9 . 15 0 . 00 124224 .49 36 . 00 45 . 00 100 . 00 i 15 . 90 0 . 00 9 . 15 0 . 00 125229 .76 36 . 00 45 . 00 100 . 00 16 . 00 0 . 00 9 .15 0 . 00 126228 .21 36 . 00 45 . 00 100 . 00 16 .10 0 . 00 9 .15 0 . 00 127219 . 98 36 . 00 45 . 00 100 . 00 I Open Channel Flew Module, Version 3 . 11 (c) Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 1 ' 9/10/98 10 :31 :27 am Sverdrup Civil Inc page 3 THE BOEING COMPANY SURFACE WATER MANAGEMENT PROJECT POST-DEV BASIN B, ROUTED TO SPRINGBROOK I I LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE DESC'RIPTION cfs) (cfs) --id- --id- c-STAGE> id (cfs) VOL (cf) WQ, POST BASIN B 0.00 0.44 4C 4C 7.27 8 0.00 12709.85 cf 2YR, POST BASIN B 0.00 3.37 4C 4C 9.12 9 1.59 36340.61 cf 5YR, POST BASIN B 0.00 4.45 4C 4C 9.14 10 2.90 36600.22 cf 10YR, POST BIASIN B 0.00 5.87 4C 4C 9.16 11 4.52 36919.35 cf 25YR, POST BASIN B 0.00 7.48 4C 4C 9.20 12 7.48 37559.19 cf 50YR, POST BASIN B 0.00 7.64 4C 4C 9.19 13 7.63 37531.40 cf 100YR,POST BFSIN B 0.00 9.05 4C 4C 9.21 14 9.05 37713.42 cf I j I I I it APPENDIX E Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt01.doc Appendix E September 1998 i j I I APPENDIX E WATER QUALITY EVALUATIONS This appendix contains information related to water quality at both the Longacres Office Park Site and the CSTC Site. Information included consists of: I i Site Map of Water Quality Collection Points,Figure E.1 Laboratory Analysis of Springbrook Creek Water Laboratory Analysis of Site#3 Water Laboratory Analysis of North Infield Creek Water Laboratory Analysis of South Marsh Outlet Water I I I i I Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt01.doc Appendix E-1 September 1998 I I s-.,` IAP .: \SCALE: NONE SPRINGBROOK CREEK PROJECT SI E j . • on% ; ,,,-- / 1 i 7---'7z'' -N cli>--1 tr/ q O ilw.r. 4 CO IRA r — 1 1.dn La n Z. J. f . C'3 O 3iiti E1 d ill1 (47---- ‘-' ''l d Her + I P+e i S ti'MARSH Zr 0)m BASIN 4 1. '.:- WETLANDS O p7ca lat:. `BASIN 3 I co i co y r `. .o fy F If , r I. ji III i BASIN 6 SW i stn sT 1tikZJaOMB'-., ' OW I ill/ I il Il I ter^^ rt, r t 1\ 10pnail • ":), ' =--------:---" -----3-- ...--, 4"" t 1 •11.AT j fir IC-)r BNRR UPRR r - ji t , o i ). 'i Y- „.,>c,0 ril i , - 1 . r ... r 12 : 'l 2 w.._- -_,j). HWAY s Z_Lej 1 L, i WEST VAl1 a GREEN RIVERt ii. , 7e. t I..rd z. w w r Alm . w r s ACCEPGtJw at7A i oi.r,=11.4117P.` n WATER QUALITY MONITORING $ MAW AVMLAWN:YAW r SURFACE PROECTMANAGEMENT FIG. E. I O1.OQ2URN( CM) 000wc LOMCAaRES UnCE PARK Longacres Park On-Site Water Quality Monitoring Laboratory-Analysis--and-Meld Testing Report Springbrook Creek March 31, 1992 Field Data Lab Analysis Stage Gage Air Temp Water C.Cond. Date Time Reading*C) Temp(•C) pH DO(mg/1) (umhoa/cm) TOC(mg/1) TSS(mg/1) Comments 06/18/91 N/A N/A 18 15.0 6.97 2.80 350- 8.5 10 06/24/91 16:00 3.86 29 17.9 7.10 2.68 335 7.5 13 07/01/91 11:15 3.85 24 19.0 7.16 2.28 374 8.2 18 07/08/91 11:10 3.77 24 16.5 7.49 3.59 319 6.5 13 07/15/91 10:00 3.79 15 16.2 6.63 3.52 364 5.4 14 07/23/91 11:05 3.77 22 16.9 7.26 2.97 343 7.4 15 07/29/91 15:00 3.76 25 20.1 7.26 3.25 389 7.9 11 08/05/91 14:10 3.71 24 19.3 7.00 1.68 - 404 - 8:5 08/12/91 14:30 3.81 26 19.7 7.25 4.26 61 13.0 11 08/19/91 10:00 3.81 23 18.2 7.45 2.70 57 7.8 12 08/26/91 10:35 3.87 17 14.5 7.14 4.25 271 7.2 7 09/02/91 10:30 3.81 22 18.2 7.32 5.42 212 7.2 7 09/10/91 13:30 3.91 23 15.6 7.14 5.48 290 5.3 8 09/16/91 10:20 4.06 23 13.4 7.19 4.90 322 6.5 9 09/23/91 11:30 4.51 22 14.6 7.16 5.44 3 5.2 4 Suspect C.Cond. 09/30/91 10:00 4.56 20 17.8 6.28 5.20 345 4.7 9 10/07/91 10:20 4.55 15 12.7 7.02 5.76 316 3.7 8 37 days no rain 10/15/91 08:40 4.51 13 11.1 6.93 5.05 344 4.6 8 10/21/91 17:20 4.41 10 12.5 7.06 4.42. 347 5.8 6 10/28/91 10:30 4.32 7 8.4 7.25 4.21 272 6.2 11 11/04/91 13:25 4.96 7 8.9 6.99 6.98 159 5.4 18 11/11/91 13:15 5.31 12 11.9 6.68 8.40 129 6.3 42 first flush rain 11/18/91 10:30 4.81 7 9.4 6.69 6.75 156 15.0 9 11/25/91 12:30 4.71 8 10.5 7.20 6.51 134 5.1 14 12/02/91 10:40 3.96 6 8.3 7.18 5.14 287 10.0 15 12/09/91 10:25 4.62 10 8.8 6.75 7.56 139 5.8 28 12/16/91 10:05 3.92 0 4.9 7.07 4.84 307 8.0 19 12/22/91 10:00 4.13 S 7.0 7.10 6.52 230 6.0 8 12/30/91 11:45 4.36 10 8.7 7.12 6.75 272 5.6 17 01/06/92 N/A 4.07 N/A 5.8 7.39 7.51 287 6.7 10 01/14/92 11:40 3.89 7 7.7 7.65 5.14 335 7.9 10 01/20/92 10:20 3.96 4 5.0 7.29 5.91 315 7.0 23 01/27/92 12:00 5.41 9 8.1 7.01 6.98 177 6.7 35 02/02/92 14:30 6.59 10 8.3 6.75 7.32 139 7.5 50 02/10/92 12:00 4.26 9 8.9 6.80 6.00 300 7.9 13 DO&Cond from lab 02/17/92 09:30 4.19 6 8.0 7.24 9.09 346 78.0 19 02/24/92 11:05 4.55 8 9.2 7.41 6.24 176 7.4 8 03/02/92 1-1:40 4.09 10 9.8 7.51 N/A 327 7.1 18 bad DO reading 03/09/92 12:25 4.01 13 10.3 8.01 5.18 332 6.9 13 03/16/92 10:30 4.25 10 9.6 6.78 6.18 234 Springbrook Creek water surface elevation-Stage Gage Reading+0.71 feet Longacres Park On-Site Water Quality Monitoring Laboratory Analysis and Field Testing Report Site #3 March 31, 1992 Field Data Lab Analysis if Samples Stage Gage Air Temp Water Temp C.Cond. ` Compositcd Date Time Reading C) C) pH DO(mg/I) (umhoa/cm) TOC(mg/1) TSS(mg/1) Comments 1 06/18/91 10:50 N/A 18 15.9 6.94 0.55 613 20.0 240 init.baseline,no rain 06/24/91 N/A N/A N/A N/A N/A N/A N/A 07/01/91 11:50 N/A 24 20.3 7.31 0.58 542 07/08/91 10:45 N/A 24 17.6 7.62 1.33 448 07/15/91 10:45 6.33 15 16.9 7.04 0.83 467 07/23/91 11:05 6.29 22 18.4 7.23 1.60 468 30.0 1300 Very high TSS 1-- - 07/29/91-- ----15:20---- -- 6.25----- ----25 ---21.8_ _ _--7.62__ -----3.13-- - --- -456 08/05/91 14:30 6.25 24 21.2 7.49 0.87 522 1 08/12/91 14:50 6.25 28 20.4 7.70 1.97 74 30.0 32 08/19/91 10:25 6.21 24 19.5 7.74 1.69 70 08/26/91 11:05 6.29 17 15.0 7.38 1.53 326 29.0 100 09/02/91 11:15 6.29 22 18.5 7.89 1.40 332 18.0 84 09/10/91 14:05 6.33 23 16.2 7.64 0.82 489 09/16/91 11:10 6.42 23 13.5 7.30 1.36 327 09/23/91 12:10 6.33 22 14.0 7.23 0.08 13 Suspect C.Cond. 09/30/91 12:45 6 20 18.8 6.43 3.00 392 10/07/91 N/A 6.00 15 10.9 7.45 3.23 358 37 days no rain 10/15/91 09:30 5.92 15 18.4 7.21 2.91 397 1 10/21/91 16:30 5.67 10 11.8 6.81 4.12 342 24.0 20 2 10/28/91 11:15 5.67 7 6.6 7.14 1.08 268 20.0 40 11/04/91 12:50 6.58 7 9.3 6.82 7.05 195 4 11/11/91 13:55 7.10 12 12.8 7.01 10.06 98 10.0 110 first flush rain 11/18/91 11:10 6.42 7 8.7 7.12 6.51 171 11.0 230 2 11/25/91 13:00 6.42 8 10.2 7.21 5.57 185 11.0 95 2 12/02/91 11:25 6.42 6 7.3 7.27 2.77 312 9.6 68 Heavy sedimentation 9 12/09/91 11:10 6.85 10 , 8.6 7.27 8.61 149 12.0 50 12/16/91 11:00 6.42 0 4.4 7.15 1.62 565 21.0 110 12/22/91 11:00 6.50 5 6.9 7.11 3.85 542 23.0 60 12/30/91 12:30 6.50 10 7.8 7.58 8.79 211 7.4 150 01/06/92 N/A 6.42 N/A 5.3 7.64 4.68 649 01/14/92 12:20 6.42 7 8.3 7.49 2.80 552 01/20/92 10:50 6.42 4 4.1 7.61 3.35 556 2 01/27/92 12:40 7.20 9 8.1 7.42 - 8.53 108 18.0 120 2 02/02/92 15:15 7.04 10 8.6 6.80 7.99 173 25.0 3600 very high TSS 4 02/10/92 12:30 6.67 9 9.8 7.00 1.50 830 26.0 41 DO It Cond from lab 02/17/92 10:15 6.60 6 8.3 7.17 4.20 779 4 02/24/92 11:50 6.68 8 9.8 732 4.58 392 28.0 200 03/02/92 12:20 6.50 10 11.5 731 N/A 673 Bad DO reading 03/09/92 13:10 630 13 11.4 7.70 2.08 650 4 03/16/92 11:15 6.30 10 9.7 7.27 3.52 463 Lab analyses N/A Longacres Park On-Site Water Quality Monitoring Laboratory-Analysis North Infield Creek At Abandoned Pumphouse March 31, 1992 Date Time TOC(mg/1) TSS(mg/1) Comments N A Very ow ow 1-1/04/91 12:30 13-.0 49 11/11/91 14:50 13.0 120 first flush rain 11/18/91 11:40 8.0 73 Longacres Park On-Site Water Quality Monitoring Laboratory Analysisysis South Marsh Outlet (Site #6) Date Time TOC(mg/1) TSS(mg/1) I Comments 11/11/91 08:30 14.0 9 first flush rain 11/18/91 12:15 14.0 15 11/25/91 17:00 20 4 Longacres Park On-Site Water Quality Monitoring Storm Event Monitoring Laboratory and Meld Testing Report March 31,1992 Field Data Air Temp Water Temp C.Cond. Site Date Time Gage Elev. (•C) C) pH DO(mg/I) (umhos/cm) Comments Springbrook 12/05/91 14:50 6.10 9 9.7 7.35 8.9 124 Storm event 1 North Infield Creek 12/05/91 15:40 9 10.1 7.06 9.8 47 Storm event 1 South Marsh Inlet 12/05/91 16:25 12.03 9 9.1 6.44 6.3 44 Storm event 1 Site ff7) Springbrook 01/29/92 12:40 6.65 10 10.0 6.90 8.7 84 Storm event 2 North Infield Creek 01/29/92 13:10 10 10.0 6.60 9.6 71 Storm event 2 South Marsh Inlet 01/29/92 13:30 12.09 10 10.5 6.60 5.1 85 Storm event 2 Site N7) Lab Analysis Biochemical Chemical Nitrate T-Org Total Total Oil Total Total Total Oxygen Oxygen +Nitrite Halogens ICeldahl &Grease Organic Phosphate Suspended Demand Demand as N (SW 9020) Nitrogen (413.1) Carbon as P Solids Site Date Time' (mg/1) (mg/1) (mg/I) (mg/1) N(mg/1) (mg/I) (mg/I) (mg/1) (mg/I) Comments Springbrook 12/05/91 14:50 10 12 0.15 0.02 0.53 5 5.6 0.33 87 Storm event 1 North Infield Creek 12/05/91 15:40 10 20 0.22 0.11 0.65 5 12 0.38 92 Storm event 1 South Marsh Inlet 12/05/91 16:25 10 16 0.03 0.02 0.50 5 11 0.17 4 Storm event 1 Site//7) Springbrook 01/29/92 13:10 10 24 0.78 0.02 0.66 9 4.8 0.18 67 Storm event 2 North Infield Creek 01/29/92 12:40 10 31 0.31 0.02 0.88 5 7.7 0.26 100 Storm event 2 South Marsh Inlet 01/29/92 13:45 10 34 0.11 0.02 0.71 8 8.8 0.16 3 Storm event 2 Site#7) I ' APPENDIX F I I I I I I I Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, ino. 014002\2220\wp\dmrpt01.doc Appendix F September 1998 APPEN D IX F WATER QUALITY DESIGN This appendix contains calculations completed for design of the project water quality wetpond located south If the enlarged CSTC pond. I Surface Wa er Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, leo. 014002\222 \wp\drnrpt0l.doc Appendix F-1 September 1998 Sverdrup JOB NUMBER BY THE BOEING COMPANY SHEET 014002 KJB SURFACE WATER MANAGEMENT PROJECT 1 DATE CHECKED STORM DRAINAGE DESIGN OF 09/02/98 JJS WETPOND SIZING SCOPE Determine the size including surface area and volume requirements for a wetpon., constructed to replace Pond `B". REFS NCES City of Renton Building Regulation, Chapter 22 "Storm and Surface Water Drainage" King County Surface Water Design Manual (KCSWDM) Waterworks, Basin Summary City of Renton Planning, Building, Public Works Memorandum from Scott Woodbury dated May 28, 1997 (review of Boeing 25-20 Building Drainage Report.) Area Weighted Runoff Coefficient for Drainanage Basin 4, Subbasin 4-5 ASSUMPTIONS Pond "B" will be fille in and all stormwater flowing to Pond "B" will be re-directed to a new wetpond(Pond"D"). Assume all treatment will be provided for in a single cell pond, similar to the CSTC project. Buildin roof areas will not be included in the wetpond sizing calculations, similar to th CSTC roject. It is also assumed that runoff from building roofs does not require wate quality treatment. Biofiltration is not required if the treatment facility has twice the volume and surface are required by the KCSWDM per Scott Woodbury's review comment #1 in City of Rento Memo, dated May 28, 1997. PROCEDURE This pr ject will not create more than 1 acre of new impervious surface subject to vehicular use; ho ever, Pond "D" will be constructed to replace Pond `B" which currently has mo than 1 acre of impervious surface area routed through it. Therefore, per Special Requirement 5 of the KCSWDM, this project must provide Special Water Quality Controls. 1. Determine Required Wetpond Surface Area: r Per KCSWDM page .3.5-1, the required design water surface area shall be 1% of the imperv.lous surface area in the drainage subbasin contributing to the facility: SA = 0.01*Aimp 014002\2220\engr\kbca1cl121.doc Sverdrup JOB NUMBER BY 1 THE BOEING COMPANY SHEET 014002 KJB SURFACE WATER MANAGEMENT PROJECT 2 DATE CHECKED I STORM DRAINAGE DESIGN OF 09/02/98 JJS WETPOND SIZING where, SA = surface area required Aimp = impervious contributing area Aimp = 382,171 ft2 (see attached basin summary), includes building roof Building roof area= 67,900 ft2 (see Area Weighted Runoff Coefficient for Drainanage Basin 4, Subbasin 4-5), deduct from total imperviuos area: Aimp = 382,171 ft2 - 67,900 ft2 Aimp = 314,271 ft2 therefore, SA = 0.01*314,271 SA = 3,143 ft2 This surface area musi be multiplied by 2 since no biofiltration is being provided. SA= 3143*2 SA= 6,286 ft2, (Pond"D"provides 68,800 ft2) 2. Determine Required Wetpond Volume: Per KCSWDM page ;1.3.5-1, the required design volume shall be a minimum of the total volume of runoff from the tributary subbasin proposed development conditions using a water quality design storm event (P2/3). The volume of the water quality storm is: P2/3 storm volume= 16,180 ft3 (see attached basin summary) Volume must be multiplied by 2 since no biofiltration is being provided(per Scott Woodbury, City of Renton). i Volume= 16,180*2 Volume= 32,360 ft3 (261,806 ft3 provided) 014002\2220\engr\kbcalcl2.doc 1/30/98 8 :5 :10 am;Sverdrup Civil Inc pag 3 BCAG HEADQUARTERS BUILDING 25-20 POST-DE LOPMENT BUILDING 25-20 BASIN B SUB-BASIN B2520 BASIN SUMMARY BASIN I : B4SB-25 . NAME: BSN 4, SUB-B2520, POST, 25YR SBUH ME'$'HODOLOGY TOTAL EA 11. 03 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE USER1 PERV IMP PRECIPIZATION i 3 .40 inches AREA. . : 2 . 26 Acres . 8 . 77 Acres TIME IN_ERVAL 10 . 00 min CN 90 . 00 98 . 00 TC 13 . 00 min 13 . 00 min I ABSTRAC ION COEFF: : 0 . 20 PEAK RA E: 7 . 96 cfs VOL: 2 . 76 Ac-ft TIME: 480 min BASIN I : B4SB-5 NAME: BSN 4, SUB-B2520, POST, 5YR SBUH ME HODOLOGY TOTAL AREA 11. 03 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE USER1 PERV IMP PRECIPI' 'ATION 2 .40 inches AREA. . : 2 . 26 Acres 8 . 77 Acres TIME INTERVAL. . . . 10 . 00 min CN 90 . 00 98 . 00 TC 13 . 00 min 13 . 00: min ABSTRACTION COEFF: 0 .20 PEAK RA E: 5 .40 cfs VOL: 1. 86 Ac-ft ' TIME: 480 min BASIN I : B4SB-50 NAME: BSN 4, SUB-B2520, POST, 50YR SBUH M#HODOLOGY TOTAL AREA 1 11. 03 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE USER1 PERV IMP PRECIPI ATION 3 .45 inches AREA. . : 2 .26 Acres 8 . 77 Acres TIME IN ERVAL. . . . • 10 . 00 min CN 90 . 00 98: 00 TC 13 . 00 min 13 . 06 min ABSTRAC ION COEFF: ' 0 .20 PEAK RA E: 8 . 09 cfs. VOL: 2 . 80 Ac-ft TIME: 480 min BASIN ID: B4SB-WQ• P-40 NAME: BSN 4, SUB-B2520, POST, WQ SBUH METHODOLOG?' ' t,2, TOTAL AEA 11 . 03 Acres BASEFLOWS : 0 . 00 cfs i RAINFALl TYPE USER1 PERV IMP PRECIPI ATION 0 .67 inches AREA. . : 2 . 26 Acres 8 . 7,7 Acres TIME IN ERVAL 10 . 00 min CN • • 90 . 00 98 . 00 TC 13 . 00 min 13 . 00, min ABSTRAC ION COEFF: 0 . 20 PEAK E: 1. 05 cfs VOL: 37 Ac-ft) TIME: 480 min I Ii Surface Water Management Project I Pond "D" Elevation Area(ft2) Area(acres) Volume (ft3) 2 22,607 0.52 3 28,620 0.66 4 35,091 0.81 31,856 5 41,932 0.96 70,367 6 49,053 1.13 115,860 7 56,357 1.29 168,565 8 63,817 1.47 228,651 8.5 68,801 1.58 261,806 9 73,785 1.69 297,453 10 84,007 1.93 376,349 11 94,124 2.16 465,414 12 104,446 2.40 564,699 13 114,974 2.64 674,409 14 137,071 3.15 800,432 I ' i- IIi i I I I I I I 014002\2220\engr\pond-vol.xls[Pond"D"] Sverdrup Civil, Inc. CITY OF RENTON PLANNINGBUILDING/PUBLIC WORKS MEMORANDUM DATE:May 28, 1997 TO: Clint Morgan FROM: Scott Woodbury5O SUBJECT:Review of Boeing 25-20 Building Plans and Drainage Report Storm Drainage Report 1. Since no biofiltration swale is being provided, the wetpond volume and surface area must be oversized by a factor of 2 to compensate. 2. The total areas for basins 3/4 and AB for the baseline,post-CSTC,and post-25-20 development scenarios are not equal as I would expect. Based on my calculations, the total areas for these scenarios(from the report are as follows:tr- Pre-CSTC(baseline)= 159.26 acres Post-CSTC= 164.64 acres Post 25-201= 161.28 acres. The discrepancy needs to be addressed. 3. Please document in the report how was the discharge in the rating curve for the main track and practice track(Basin B)release rates were determined. In routing flows from Basin 4/B through the practice track, the rating curve for the release rate from-the practice track into Springbrook Creek should assume a 2-year current condition tailwater in Springbrook Creek of•9.0 feet NGVD). Therefore, there would be no outflow below elevation 9 and the release rates above elevation 9 would be based on outlet control conditions for the 36" outlet from the practice track. The stage-storage should assume no available storage below the elevation 9. f,4. The report was not consistent in labeling the three development scenarios and basin areas baseline post-CSTC, post-25-20). The terms pre-development and post-development were P used many times without qualifying which pre- and post-development case was meant. I think it would be helpful for the consultant to do a thorough review of the entire report to ensure consistency and clarity in these areas. Ji 5. Please include a brief explanation in the report of how the total release rates from Basin 4/B listed in Table D.1 were determined (i.e., for the pre-25-20 cases, the output hydrograph from routing Basins B 1 &B4 through main track were added to hydrographs from Basins B2 and B3. The combined hydrographs were then routed through the practice track to determine the total release rate for Basin B)., 6. Other comments are alsoI noted within the text of the report. i I I The Boeing Company Surface Water Management Project(SWMP) Area Weighted Runoff Coefficient Pre-Development SWMP Drainage Basin B South Main Track Basin) Sub-Basin 4-5 Soil Hydrologic Curve Land Use Area Weight • Weighted Group Group Number Description st7 Curve Number Ur D 1 98 Building Roofs 67,900 14%13.84 Ur D 98 Pavements 314,271 65%64.07 Ur D 1 90 Landscaping(good) 98,495 20%18.44 TOTALS 1 480,666 100% 96.36 Notes: 1. Soil groups estimated from Soil Survey of King County Area, Washington,Des Moines Quadrangle 1973 2. Hydrologic groups determined from King County Surface Water Design Manual, Figure 3.5.2A 3. Curve Numbers determined from King County Surface Water Design Manual,Table 3.5.2B Impervious area(curve number>=98) 8.77 Acres Impervious area curve number 98.00 Pervious area(curve number<98) 2.26 Acres Pervious area curve number 90.00 Basin Composite Curve Number 96.36 Basin Total Area 11.03 Acres 1 I I 013747/2210/engr/-Kbcalcl6.xls[Pre-Basin 4-5] 9/10/98 Sverdrup Civil,Inc. APPENDIX G Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Mo. 014002\2220\wp\dmrpt0l.doc Appendix G September 1998 APPEN IX G CONVEYANCE SYSTEM DESIGN This appendix contain calculations detailing the design of the project conveyance systems. This information is not required for the Drainage Report for Conceptual Drainage Plan, but will be provided in the final drainage report. Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\dmrpt0l.doc Appendix G-1 September 1998 APPENDIX H I I i l I 1 Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\drnrpt0l.doc J Appendix H September 1998 I I APPE IX H GROUNDWATER INFORMATION This appendix contains information related to the Longacres Office Park groundwater conditions. This information was produced by GeoEngineers, Inc., and is taken from Report, Geotechnical Engineering and Hydrogeological Services, CSTC Pond Expansion Boeing LongacreIs Park, Renton,; Washington, dated April 23, 1998. Information included consists of: 1V{onitor Well Location Site Plan, 1998, Figure H.1 Cross Section of Site, 1998, Figure H.2 Monitor Well Water Level Measurements, 1998,tabulated information Additional information related to the CSTC Main Pond was produced by GeoEngineers, Inc., anci reported in Geotechnical Consultation Potential Lake Impacts, Boeing Longacres Park, Renton, Washington for Boeing Support Services, dated December 9, 1991. i I Surface Water Management Drainage Report for Conceptual Drainage Plan Sverdrup Civil, Inc. 014002\2220\wp\drnrpt01.doc Appendix H-1 September 1998 11 fto JLr s ; F'q 49,. Alk.<' E CED 54,31 Fi`•`` :E NWiif DIVERSE (REPL4 E ENT) 89,55 F L: ', OFEN WATER (RE?LA E ENT) \ 65,41 — F r n3_ A.°i. , ,<.:,,N;• •1•:' ••• ,s 1 M NT AREA = 154,97 F 1 / I/• AWc•-Or:. `'``' \.`;; ;< „_ 1 TOTAL MEASURED W TL ND AREAEe.::'• it jam//!.- •c1. 'i. : a\.'.YS:a:',.a•\\\it.;.>wi•\\ \\\'.` LI, i t.r ,'? ems.„z\•4\\'a C‘I/,_ • I"...sit 4u,..%,,,s,.5-4.;,,k.m ..)::. ,.T :ii.. ,,,,•:;,.*.-iii,-,ik-k•,...,,,,,.., il. I iII: i. T tY', v o l\\ $::xis:\ 4 \\:..\\ i, 1. +\ \h \` ::\\ \`\i:.\,. a; I I' '' MW 25 • \, .,\`, `' '' \ `,; , , B— 5 .,i( k\'' • ` ''s•\\ •'''' •" ." t. '\'''s'`...•• y R MW-2:C:11..:7 j MW-38 , `:\\\ • \\ ,.'A t iMW-39 A• , \ ems 7,,,-.7r.•,e„..seeedt.,--'--••---'—• ri7-......„ 44• 1 1 fig`\ i, i h .. O Q MW-23 \ .,c'^.w` i,„.1v.\- 7.,,$.;-•;„.7....:.\i, r i•,` '..,; t e 1 rF ss,. .. y-• l'! ti.;a'oa\ 1 4.:,:'i'r •.t";•.::•_ k, -y. ,'?t r 1, tf L: e„\,,.:,-f. Fvn• s:• ;s r ri L• T ) TtIt..•.1. a,\'?';i..:.,::;rll\ tq i:•,,?iYrltry(i•,'Y:-V,,V a,r" sat-`L•- r' p'• la/''L •,!' .. • , !bcMW 20 O ;:.:.,t •\ft,.:,,,. ., MW-41 Y : t rS a._t' I 9. J'. !'•'r; f:^i•,....,,:;:-.- i'i J fir:'a1,:,l.,'t•:,\. L° ttl - f •• M —Q /14 / l', 6 a is s?.:,:.- ' c' ,a::;: rI • :\., •h!• r' r.. J f. i•.. r!t . 1. I-:ie.. '. y..•,;< ` . : 1 MW r,`F a.: ? MW 45 '`v s r I .r l ui r.%% :'s.C••,z: 1\`a \,\\ r:: ejam , t :y}y• -.,\w: 36 4,4• s 'tl t. r';,i•1i' ..- i• o.5rr ,1:`:.. d Ar.'s^- e .e .a.. • r • t,'. l\ \a _.?. t:i•' -1% .\\,.,• \. v::•,• :'•;,• \ \ 'D \\ l. .,• 1`:,:.o-..'^ r+'S+ •V 9- r W-44 MW-37 ` i 1` I i /:: "secs>. v•. k a o a t• yr'=•'T'.----' M r" mot.•l I0c 1 l ice`, v\\\, `:`i'n,,,.v. r 1 M \\\\\\\\\\\\\\\\\\\\\\ i i . 7`' ham t ~" r>,.,.. may'__isT-, — ._ 2....._ 7.,..„. i31 co rn \11... I•' r . Alli o- f- gh=,) — K -M Nl DEI1 I 1 I • 1 J I I I I I ,I ,I o EXPLANATION: I N MW-38 • MONITORING WELL (1998) o M A - 0—MONITORING—WELL-t1S9T) iE' 7 Z B-35---BORING (1991) 0 150 300 Al IA' SOIL PROFILE SCALE IN FEET 1 SITE PLAN 1 z Note: The locations of all features shown are approximate. 4,Geo Engineers FIGURE H•o Reference: Plan entitled "Preliminary Wetlands. Area, Longacres Office Park" by Bruce Dees & Associates, 03/30/98. ill I 0.. 3 CD in in ID N1U330 a)in rn o a co N N a) r- O 1 O33 N0 CD N A'A 4-N MM i vo wu7o I20 — o N I. M CO 20 NN mW 0 CO 33 33 N co M 3 m Ground Surface 2 2 2 Existing — 2 2 2 2 Silt and organic silt with occasional layers i 10 — Pond of silty sand (ML to OL) I 100 vZ1- 0 W N N 10 — Fine to medium sand with 10 varying -amounts of silt- (SP-to SM) — c, a ai co N N- -- O N r- O 0 N N O N_ O a — HORIZONTAL SCALE: 1" = 100' VERTICAL SCALE: 1" = 10' VERTICAL EXAGGERATION: 10X Notes: 1. The subsurface conditions shown are based on interpolation between SOIL PROFILE A-A' widely spaced explorations and should be considered app 49actualsubsurfaceconditionsmayvaryfromthoseshown. Georoximate; 0Engineers02. Refer to Figure 2 for location of Profile A—A'. i FIGURE \-k. n A TABLE 1 GROUND WATER ELEVATION MEASUREMENTS CSTC POND EXPANSION BOEING LONGACRES PARK RENTON,WASHINGTON Ground i Depth to Surface Top of Casing Ground Water Ground Water Monitoring Elevation Elevation Top of Casing) Elevation Well (feet) feet) Date Time feet) feet) MW-38 11.07 I 13.07 04/09/98 3.58 9.49 04/16/98 4.05 9.02 04/21/98 4.26 8.81 05/21/98 5.22 7.85 I 06/10/98 5.25 7.82 06/24/98 11:30 AM 5.49 7.58 12:41 PM 5.50 7.57 r 2:31 PM 5.48 7.59 4:02 PM 5.50 7.57 07/20/98 6.47 6.60 08/27/98 8.45 4.62 09/18/98 9.02 4.05 MW-39 10.93 13.13 04/09/98 6.15 6.98 04/16/98 6.40 6.73 04/21/98 6.40 6.73 05/21/98 6.65 6.48 06/10/98 6.80 6.33 06/24/98 11:29 AM 6.74 6.39 12:40 PM 6.74 6.39 2:30 PM 6.73 6.40 2:01 PM 6.73 6.40 07/20/98 6.89 6.24 08/27/98 7.01 6.12 09/18/98 7.07 6.06 MW-40 12.76 14.64 04/09/98 4.10 10.54 04/16/98 4.59 10.05 04/21/98 4.96 9.68 05/21/98 6.51 8.13 06/10/98 6.93 7.71 06/24/98 11:26 AM 7.41 7.23 12:38 PM 7.41 7.23 2:28 PM 7.39 7.25 4:00 PM 7.40 7.24 07/20/98 8.52 6.12 08/27/98 Dry 09/18/98 Dry MW-41 12.39 14.99 04/09/98 7.65 7.34 04/16/98 7.94 7.05 04/21/98 7.89 7.10 05/21/98 8.13 6.86 06/10/98 8.38 6.61 06/24/98 11:24 AM 8.29 6.70 12:37 PM 8.28 6.71 2:27 PM 8.26 6.73 3:59 PM 8.27 6.72 07/20/98 8.44 6.55 08/27/98 8.53 6.46 09/18/98 8.62 6.37 MW'42 15.44 18.09 04/09/98 7.02 11.07 04/16/98 7.20 10.89 04/21/98 7.29 10.80 05/21/98 8.57 9.52 06/10/98 9.00 9.09 I P:\000to099\0120226\021finals\012022602-t1 Ground Depth to Surface Top of Casing Ground Water Ground Water Monitoring Elevation Elevation Top of Casing) Elevation Well (feet) feet) Date Time feet) feet) 06/24/98 11:21 AM 9.31 8.78 12:35 PM 9.31 8.78 2:25 PM 9.30 8.79 3:58 PM 9.30 8.79 07/20/98 10.62 7.47 08/27/98 11.30 6.79 09/18/98 11.56 6.53 MW-43 17.21 19.16 04/09/98 7.35 11.81 04/16/98 7.75 11.41 04/21/98 7.86 11.30 05/21/98 8.96 10.20 06/10/98 9.35 9.81 06/24/98 11:19 AM 9.74 9.42 12:33 PM 9.74 9.42 2:23 PM 9.74 9.42 3:56 PM 9.75 9.41 07/20/98 10.59 8.57 08/27/98 11.62 7.54 09/18/98 12.02 7.14 MW-44. 16.51 18.96 04/09/98 7.15 11.81 04/16/98 7.45 11.51 I 04/21/98 7.52 11.44 05/21/98 8.75 10.21 06/10/98 9.05 9.91 06/24/98 11:17 AM 9.43 9.53 12:31 PM 9.43 9.53 2:20 PM 9.41 9.55 3:54 PM 9.43 9.53 07/20/98 10.20 8.76 08/27/98 Dry 1_ 09/18/98 Dry MW-45 16.69 19.25 04/09/98 7.54 11.71 04/16/98 7.84 11.41 04/21/98 7.92 11.33 05/21/98 9.13 10.12 06/10/98 9.45 9.80 06/24/98 11:16 AM 9.83 9.42 12:30 PM 9.83 9.42 I 2:20 PM 9.84 9.41 3:53 PM 9.85 9.40 07/20/98 10.62 8.63 8/27/98 11.63 7.62 09/18/98 12.04 7.21 MW-46 15.59 18.49 04/09/98 7.56 10.93 04/16/98 7.72 10.77 04/21/98 7.71 10.78 05/21/98 8.74 9.75 06/10/98 9.05 9.44 06/24/98 11:12 AM 9.32 9.17 12:27 PM 9.33 9.16 2:17 PM 9.32 9.17 3:50 PM 9.32 9.17 07/20/98 10.17 8.32 08/27/98 10.94 7.55 09/18/98 11.29 7.20 P-1 11.22 06/24/98 11:49 AM Dry 12:49 PM Dry 2:50 PM Dry I 4:13 PM Dry 07/20/98 Dry 08/27/98 Dry P-2 12.19 06/24/98 11:52 AM 3.57 8.62 P:\000to099\0120226\02\finals\012022602-t1 I Ground Depth to Surface Top of Casing Ground Water Ground Water Monitoring Elevation Elevation Top of Casing) Elevation Well (feet) feet) Date Time feet) feet) 12:52 PM 3.57 8.62 2:47 PM 3.59 8.60 4:09 PM 3.63 8.56 07/20/98 Dry 08/27/98 Dry P-3 11.38 06/24/98 11:42 AM 3.51 7.87 12:49 PM 3.42 7.96 2:44 PM 3.13 8.25 4:07 PM 3.04 8.34 07/20/98 0.50 10.88 P-4 13.19 06/24/98 11:36 AM Dry 12:47 PM Dry 2:40 PM Dry 4:05 PM Dry 07/20/98 Dry P-5 12.98 06/24/98 11:39 AM Dry 12:45 PM Dry 2:40 PM Dry 4:04 PM Dry 07/20/98 Dry Note: Ground surface elevations provided by W&H Pacific 000to099\0120226\02 finals\012022602-0 KING COUNTY, WASHINGTON AND INCORPORATED AREAS Volume 1 of 4 COMMUNITY NAME COMMUNITY NUMBER *ALGONA, CITY OF 530072 AUBURN, CITY OF 530073 *BEAUX ARTS VILLAGE, TOWN OF 530242 BELLEVUE, CITY OF 530074 BLACK DIAMOND, CITY OF 530272 BOTHELL, CITY OF 530075 BURIEN, CITY OF 530321 CARNATION, CITY OF 530076 *CLYDE HILL, CITY OF 530279 COVINGTON, CITY OF 530339 DES MOINES, CITY OF 530077 DUVALL, CITY OF 530282 ENUMCLAW, CITY OF 530319 FEDERAL WAY, CITY OF 530322 *HUNTS POINT, TOWN OF 530288 ISSAQUAH, CITY OF 530079 KENMORE, CITY OF 530336 KENT, CITY OF 530080 KING COUNTY, UNINCORPORATED AREAS 530071 KIRKLAND, CITY OF LAKE FOREST PARK, CITY OF *MAPLE VALLEY, CITY OF 530081 530082 530078 *No Special Flood Hazard Areas Identified COMMUNITY NAME COMMUNITY NUMBER *MEDINA, CITY OF 530315 *MERCER ISLAND, CITY OF 530083 MUCKLESHOOT INDIAN RESERVATION 530165 NEWCASTLE, CITY OF NORMANDY PARK, CITY OF 530134 530084 NORTH BEND, CITY OF 530085 PACIFIC, CITY OF 530086 REDMOND, CITY OF 530087 RENTON, CITY OF 530088 SAMMAMISH, CITY OF 530337 SEATAC, CITY OF 590320 SEATTLE, CITY OF 530089 SHORELINE, CITY OF 530327 SKYKOMISH, TOWN OF 530236 SNOQUALMIE, CITY OF 530090 TUKWILA, CITY OF 530091 WOODINVILLE, CITY OF 530324 *YARROW POINT, TOWN OF 530309 PRELIMINARY: Federal Emergency Management Agency Flood Insurance Study Number 53033CV001B King County Notice This preliminary FIS report includes only revised Flood Profiles and Floodway Data tables. See “Notice to Flood Insurance Study Users” page for additional details. NOTICE TO FLOOD INSURANCE STUDY USERS Communities participating in the National Flood Insurance Program have established repositories of flood hazard data for floodplain management and flood insurance purposes. This Flood Insurance Study (FIS) report may not contain all data available within the Community Map Repository. Please contact the Community Map Repository for any additional data. The Federal Emergency Management Agency (FEMA) may revise and republish part or all of this FIS report at any time. In addition, FEMA may revise part of this FIS report by the Letter of Map Revision process, which does not involve republication or redistribution of the FIS report. Therefore, users should consult with community officials and check the Community Map Repository to obtain the most current FIS report components. Selected Flood Insurance Rate Map panels for this community contain information that was previously shown separately on the corresponding Flood Boundary and Floodway Map panels (e.g., floodways, cross sections). In addition, former flood hazard zone designations have been changed as follows: Old Zone(s) New Zone Al through A30 AE V1 through V30 VE B X C X Initial Countywide FIS Effective Date: September 29, 1989 Revised Countywide Date(s): May 16, 1995 May 20, 1996 March 30, 1998 November 8, 1999 December 6, 2001 April 19, 2005 To Be Determined This preliminary FIS report does not include unrevised Floodway Data Tables or unrevised Flood Profiles. These Floodway Data Tables and Flood Profiles will appear in the final FIS report. i TABLE OF CONTENTS Volume 1 Page 1.0 INTRODUCTION ..................................................................................................................... 1 1.1 Purpose of Study ........................................................................................................... 1 1.2 Authority and Acknowledgements ............................................................................... 1 1.3 Coordination ................................................................................................................. 6 1.3.1 Revision 1 – Miller Creek .............................................................................. 16 1.3.2 Revision 2 – Snoqualmie River ..................................................................... 16 1.3.3 Revision 3 – Raging River ............................................................................. 16 1.3.4 Revision 4 – North Fork Issaquah Creek, Bear Creek, Evans Creek, Middle Fork Snoqualmie River, South Fork Skykomish River, Upper Middle Fork Snoqualmie River, North Fork River, Tate Creek, South Fork Snoqualmie River ................................................. 16 1.3.5 Revision 5 – North Creek .............................................................................. 18 1.3.6 Revision 6 – Tolt River, Upper South Fork Snoqualmie River ..................... 18 1.3.7 Revision 7 – Snoqualmie River, Issaquah Creek ........................................... 18 1.3.8 Revision 8 – Patterson Creek, Lower Snoqualmie River, Springbrook Creek, Cedar River, Green River ......................................................... 19 1.3.9 Revision 9 – Puget Sound, Sammamish, White River .................................. 20 2.0 AREA STUDIED .................................................................................................................... 21 2.1 Scope of Study ............................................................................................................ 21 2.1.1 Revision 1 – Miller Creek .............................................................................. 28 2.1.2 Revision 2 – Snoqualmie River ..................................................................... 29 2.1.3 Revision 3 – Raging River ............................................................................. 29 2.1.4 Revision 4 – North Fork Issaquah Creek, Bear Creek, Evans Creek, Middle Fork Snoqualmie River, South Fork Skykomish River, Upper Middle Fork Snoqualmie River, North Fork River, Tate Creek ................................................................................ 29 2.1.5 Revision 5 – North Creek .............................................................................. 30 2.1.6 Revision 6 – Tolt River, Upper South Fork Snoqualmie River ..................... 31 2.1.7 Revision 7 – Snoqualmie River, Issaquah Creek ........................................... 31 2.1.8 Revision 8 – Patterson Creek, Lower Snoqualmie River, Springbrook Creek, Cedar River, Green River, Kelsey Creek .................................. 32 2.1.9 Revision 9 – Puget Sound, Sammamish River, White River ......................... 33 2.2 Community Description .............................................................................................. 34 2.3 Principal Flood Problems ............................................................................................ 41 2.3.1 Revision 1 – Miller Creek .............................................................................. 54 2.3.2 Revision 2 – Snoqualmie River ..................................................................... 55 2.3.3 Revision 3 – Raging River ............................................................................. 55 ii Table of Contents (continued) Volume 1 2.3.4 Revision 4 – North Fork Issaquah Creek ....................................................... 55 2.3.5 Revision 5 – North Creek .............................................................................. 56 2.3.6 Revision 6 – Tolt River, Upper South Fork Snoqualmie ............................... 56 2.3.7 Revision 7 – Snoqualmie River ..................................................................... 56 2.3.8 Revision 8 – Patterson Creek, Lower Snoqualmie River, Springbrook Creek, Cedar River, Green River, Kelsey Creek ................................ 57 2.3.9 Revision 9 – Puget Sound, Sammamish River, White River ......................... 59 2.4 Flood Protection Measures ......................................................................................... 60 2.4.1 Revision 1 – Miller Creek .............................................................................. 64 2.4.2 Revision 2 – Snoqualmie River ..................................................................... 64 2.4.3 Revision 3 – Raging River ............................................................................. 64 2.4.4 Revision 4 – North Fork Issaquah Creek ....................................................... 65 2.4.5 Revision 5 – North Creek .............................................................................. 65 2.4.6 Revision 6 – Tolt River, Upper South Fork Snoqualmie ............................... 65 2.4.7 Revision 7 – Snoqualmie River, Issaquah Creek ........................................... 65 2.4.8 Revision 8 – Patterson Creek, Cedar River, Green River, Kelsey Creek ...... 65 2.4.9 Revision 9 – Puget Sound, Sammamish River, White River ......................... 66 3.0 ENGINEERING METHODS .................................................................................................. 67 3.1 Hydrologic Analyses ................................................................................................... 67 3.1.1 Revision 1 – Miller Creek .............................................................................. 73 3.1.2 Revision 2 – Snoqualmie River ..................................................................... 75 3.1.3 Revision 3 – Raging River ............................................................................. 75 3.1.4 Revision 4 – North Fork Issaquah Creek, Bear Creek, Middle Fork Snoqualmie River, South Fork Skykomish River, North Fork Snoqualmie River ..................................................................... 75 3.1.5 Revision 5 – North Creek .............................................................................. 78 3.1.6 Revision 6 – Tolt River, Upper South Fork Snoqualmie, Middle and South Fork Snoqualmie River .................................................. 79 3.1.7 Revision 7 – Snoqualmie River, Issaquah Creek ........................................... 80 3.1.8 Revision 8 – Patterson Creek, Lower Snoqualmie River, Springbrook Creek, Cedar River, Green River, Kelsey Creek .................................. 83 3.1.9 Revision 9 – Sammamish River, White River ............................................... 86 3.2 Hydraulic Analyses ................................................................................................... 100 3.2.1 Revision 1 – Miller Creek ............................................................................ 105 3.2.2 Revision 2 – Snoqualmie River ................................................................... 107 3.2.3 Revision 3 – Raging River ........................................................................... 108 iii Table of Contents (continued) Volume 1 3.2.4 Revision 4 – North Fork Issaquah Creek, Bear Creek, Evans Creek, Cottage Creek, Middle Fork Snoqualmie River, South Fork Skykomish River, North Fork Snoqualmie River...................................... 109 3.2.5 Revision 5 – North Creek ............................................................................ 120 3.2.6 Revision 6 – Tolt River, Upper South Fork Snoqualmie ............................. 122 3.2.7 Revision 7 – Snoqualmie River, Issaquah Creek ......................................... 123 3.2.8 Revision 8 – Patterson Creek, Lower Snoqualmie River, Springbrook Creek, Cedar River, Green River, Kelsey Creek ................................ 128 3.2.8.1 Springbrook Creek .................................................................. 141 3.2.8.2 Green River ............................................................................ 144 3.2.9 Revision 9 – Sammamish River, White River ............................................. 154 Volume 2 3.3 Wave Height Analysis .............................................................................................. 161 3.4 Vertical Datum .......................................................................................................... 162 4.0 FLOODPLAIN MANAGEMENT APPLICATIONS ........................................................... 165 4.1 Floodplain Boundaries .............................................................................................. 166 4.2 Floodways ................................................................................................................. 167 4.3 Base Flood Elevations .............................................................................................. 250 4.4 Velocity Zones .......................................................................................................... 250 5.0 INSURANCE APPLICATION ............................................................................................. 251 6.0 FLOOD INSURANCE RATE MAP ..................................................................................... 252 7.0 OTHER STUDIES ................................................................................................................. 253 8.0 LOCATION OF DATA ......................................................................................................... 253 9.0 BIBLIOGRAPHY AND REFERENCES .............................................................................. 255 10.0 REVISION DESCRIPTIONS ................................................................................................ 270 10.1 First Revision ............................................................................................................ 270 10.2 Second Revision ....................................................................................................... 271 10.3 Third Revision .......................................................................................................... 272 10.4 Fourth Revision ......................................................................................................... 272 10.5 Fifth Revision ........................................................................................................... 273 10.6 Sixth Revision ........................................................................................................... 273 10.7 Seventh Revision ...................................................................................................... 274 10.8 Eighth Revision ......................................................................................................... 275 10.9 Ninth Revision .......................................................................................................... 282 iv Table of Contents (continued) FIGURES Volume 2 Figure 1 – Transect Schematic ............................................................................................................ 162 Figure 2 – Floodway Schematic ........................................................................................................ 250 TABLES Volume 1 Table 1 – USGS Gages ....................................................................................................................... 68 Table 2 – Summary of Discharge ......................................................................................................... 89 Table 3 – Summary of Elevations ....................................................................................................... 100 Table 4 – Manning's “n” values .......................................................................................................... 159 Volume 2 Table 5 – Datum Conversion Factors ................................................................................................. 163 Table 6 – Floodway Data .................................................................................................................... 169 Table 7 – Community Map History .................................................................................................... 254 EXHIBIT Volume 2 Exhibit 1 – Flood Profiles Bear Creek Panels 01P-10P No Profile Panel 11P Big Soos Creek Panels 12P-21P Black River Panel 22P Cedar River Panels 23P-34P Cherry Creek Panel 35P Coal Creek Panels 36P-39P Des Moines Creek Panel 40P East Branch of West Tributary Kelsey Creek Panels 41P-44P East Fork Issaquah Creek Panels 45P-47P v Table of Contents (continued) EXHIBIT (continued) Volume 2 (continued) Exhibit 1 – Flood Profiles (continued) Evans Creek Panels 48P-49P Volume 3 Forbes Creek Panels 50P-54P Gardiner Creek Panel 55P Gilman Boulevard Overflow Issaquah Creek Panel 56P Green River Panels 57P-78P Holder Creek Panel 79P Issaquah Creek Panels 80P-87P Kelsey Creek Panels 88P-95P Little Bear Creek Panels 96P-97P Longfellow Creek Panels 98P-102P Lower Overflow Panel 103P Lyon Creek Panels 104P-105P Maloney Creek Panels 106P May Creek Panels 107P-112P May Creek Tributary Panel 113P McAleer Creek Panels 114P-115P Mercer Creek Panel 116P Meydenbauer Creek Panels 117P-118P Middle Fork Snoqualmie River Panels 119P-124P Middle Overflow Panel 125P Mill Creek-Auburn Panels 126P-131P Mill Creek-Kent Panels 132P-136P Miller Creek Panels 137P-140P North Branch Mercer Creek (North Valley) Panels 141P-145P North Creek Panels 146P-147P No Profile Panels 148P North Fork Issaquah Creek Panel 149P North Fork Meydenbauer Creek Panel 150P North Fork Snoqualmie River Panels 151P-152P North Fork Thornton Creek Panels 153P-158P Patterson Creek Panels 159P-162P Patterson Creek Overflow Reach Panel 163P Raging River Panels 164P-171P Richards Creek Panels 172P-183P Volume 4 Richards Creek East Tributary Panel 184P Richards Creek West Tributary Panel 185P vi Table of Contents (continued) EXHIBIT (continued) Volume 4 (continued) Exhibit 1 – Flood Profiles (continued) Right Channel Mercer Creek Panel 186P Rolling Hills Creek Panel 187P Sammamish River Panels 188P-193P Snoqualmie River Panels 194P-209P Snoqualmie River Overflow Reach 1 Panels 210P-211P Snoqualmie River Overflow Reach 2 Panels 212P-213P Snoqualmie River Overflow Reach 3 Panels 214P-215P Snoqualmie River Overflow Reach 4 Panel 216P Snoqualmie River Overflow Reach 5 Panels 217P-218P Snoqualmie River Overflow Reach 6 Panel 219P South Fork Skykomish River Panels 220P-230P South Fork Snoqualmie River (Without Levee) Panel 231P South Fork Snoqualmie River (With Levee) Panels 232P-238P South Fork Snoqualmie River (Without Left Levee) Panels 239P-243P South Fork Snoqualmie River (Without Right Levee) Panels 244P-248P South Fork Thornton Creek Panels 249P-253P Springbrook Creek Panels 254P-258P SW 23rd Street Drainage Channel Panel 259P Swamp Creek Panels 260P-262P Swamp Creek Overbank Panel 263P Thornton Creek Panels 264P-266P Tibbetts Creek Panels 267P-271P Tolt River (With Levee) Panels 272P-274P Tolt River (Without Left Levee) Panel 275P Tolt River (Without Right Levee) Panel 276P Upper North Overflow Panel 277P Upper South Overflow Panel 278P Vasa Creek Panel 279P Walker Creek Panel 280P West Fork Issaquah Creek Panels 281P-282P West Tributary Kelsey Creek Panels 283P-287P White River Panels 288P-293P White River (Left Bank Overflow) Panel 294P Yarrow Creek Panels 295P-296P PUBLISHED SEPARATELY Flood Insurance Rate Map Index Flood Insurance Rate Maps 1 FLOOD INSURANCE STUDY KING COUNTY, WASHINGTON AND INCORPORATED AREAS 1.0 INTRODUCTION 1.1 Purpose of Study This Flood Insurance Study (FIS) investigates the existence and severity of flood hazards in the geographic area of King County, Washington, including the Cities of Algona, Auburn, Bellevue, Black Diamond, Bothell, Burien, Carnation, Clyde Hill, Covington, Des Moines, Duvall, Enumclaw, Federal Way, Issaquah, Kenmore, Kent, Kirkland, Lake Forest Park, Maple Valley, Medina, Mercer Island, Newcastle, Normandy Park, North Bend, Pacific, Redmond, Renton, Sammamish, SeaTac, Seattle, Shoreline, Snoqualmie, Tukwila, Woodinville, the Towns of Beaux Arts Village, Hunts Point, Skykomish, Yarrow Point, the Muckleshoot Indian Reservation, and the unincorporated areas of King County (hereinafter referred to collectively as King County), and aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. This study has developed flood risk data for various areas of the community that will be used to establish actuarial flood insurance rates and to assist the community in its efforts to promote sound floodplain management. Minimum floodplain management requirements for participation in the National Flood Insurance Program (NFIP) are set forth in the Code of Federal Regulations at 44 CFR, 60.3. Please note that the City of Milton is geographically located in King and Pierce Counties. The flood-hazard information for the City of Milton is for information purposes only. See Pierce County separately published FIS report and FIRM for City of Milton. Please note that the Cities of Algona, Clyde Hill, Maple Valley, Medina, and Mercer Island and the Towns of Beaux Arts Village, Hunts Point, and Yarrow Point have No Special Flood Hazard Areas Identified. In some States or communities, floodplain management criteria or regulations may exist that are more restrictive or comprehensive than the minimum Federal requirement. In such cases, the more restrictive criteria take precedence and the State (or other jurisdictional agency) will be able to explain them. 1.2 Authority and Acknowledgments The sources of authority for this FIS are the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. 2 The hydrologic and hydraulic analyses for the original King County study were performed by the U.S. Army Corps of Engineers (USACE), Seattle District, for the Federal Emergency Management Agency (FEMA), under Inter-Agency Agreement No. IAA-H-2-73, Project Order No. 14, and Inter-Agency Agreement No. IAA-H-19-74, Project Order Nos. 1 and 15. This study was completed in August 1976. The Enplan Corporation, Consulting Engineers, Kirkland, Washington, assisted in the transfer of map data from photomosaic and topographic maps to the report work maps for the Seattle District, USACE. The hydrologic and hydraulic analyses for the Tolt River were performed by the U.S. Soil Conservation Service (SCS) for Flood Hazard Analyses, Tolt River, and King County, Washington. Hydrologic and hydraulic analyses for the communities of King County were performed by study contractors and are summarized below: Contract Completion Community Contractor Number Date King County CH2M Hill EMW-85-C-1893 June 1987 (revised study) Northwest, Inc., for FEMA City of Seattle CH2M Hill EMW-85-C-1893 June 1987 (revised study) Northwest, Inc., for FEMA Portion of Upper USACE, Inter-Agency February 1988 Green River Valley Seattle District, Agreement No. upstream from Auburn for FEMA IAA-EMW-E- 1153 Project Order No. 1 City of Auburn Tudor Engineering H-4025, May 1978 (original study) Co., for FEMA Amendment 4 City of Auburn CH2M Hill EMW-85-C-1893 June 1987 (revised study) Northwest, Inc., for FEMA 3 Contract Completion Community Contractor Number Date City of Bellevue USGS, Water Inter-Agency May 1977 Resources Agreement No. Division for FEMA IAA-H-8-76, Project Order No. 3 City of Carnation CH2M Hill, Inc., H-4600 August 1978 for FEMA Harper Houf Righeliis Inc. N/A May 2002 City of Des Moines CH2M Hill, Inc., H-4600 September 1978 for FEMA City of Duvall CH2M Hill, Inc., H-4600 September 1978 for FEMA NHC Inc. N/A N/A City of Issaquah Tudor Engineering H-4025 September 1977 Co. for FEMA City of Kent Tudor Engineering H-4025 June 1979 (original study) Co. for FEMA Amendment No. 13 City of Kent CH2M Hill EMW-85-C-1893 June 1988 (revised study) Northwest, Inc., for FEMA City of Kirkland Tudor Engineering H-4025 December 1977 Co., for FEMA City of Lake Forest Park CH2M Hill, Inc., H-4600 August 1978 for FEMA City of Normandy Park CH2M Hill, Inc., H-3815 June 1976 for FEMA City of North Bend CH2M Hill, Inc., H-4600 October 2001 for FEMA City of Pacific CH2M Hill, Inc., H-4600 April 1979 for FEMA 4 Contract Completion Community Contractor Number Date City of Redmond Tudor Engineering N/A August 1977 Co., for FEMA City of Redmond USACE, Seattle N/A August 1976 (additional hydrologic and District for hydraulic analyses) FEMA City of Renton Tudor Engineering H-4025 July 1979 (original study) Co. for FEMA City of Renton CH2M Hill, EMW-85-C-1893 June 1987 (revised study) Northwest, Inc., for FEMA Town of Skykomish CH2M Hill, Inc., H-4600 July 1979 for FEMA Town of Snoqualmie CH2M Hill, Inc., H-4810 July 1981 for FEMA (additional data from USACE) City of Tukwila Tudor Engineering H-4025 April 1979 Co., for FEMA Amendment No.10 King County NHC Inc. EMW-90-C-3134 September 1991 Unincorporated Areas Revision 1 City of SeaTac NHC Inc. EMW-90-C-3134 September 1991 Revision 1 City of Bothell NHC Inc. EMW-90-C-3134 September 1991 Revision 1 City of Normandy Park NHC Inc. EMW-90-C-3134 September 1991 Revision 1 City of Snoqualmie NHC Inc. EMW-90-L-3134 May 1995 Revision 2 5 Contract Completion Community Contractor Number Date King County Harper Righellis Inc, Portland N/A May 20, 1996 Revision 3 King County Harper Righellis EMW-93-C-4152 December 2001 Unincorporated Areas NHC Inc. Revision 4 Town of Skykomish Harper Righellis December 2001 Revision 4 City of Issaquah NHC Inc. EMW-93-C-4152 September 1995 Revision 4 City of Redmond NHC Inc. EMW-93-C-4152 September 1995 Revision 4 City of Bothell NHC Inc. EMW-93-C-4152 April 1994 Revision 5 King County Harper Houf December 2001 Unincorporated Areas Righhellis Inc. Revision 6 King County Montgomery Water December 2001 Unincorporated Areas Group Inc. Revision 6 City of Issaquah Montgomery Water N/A August 2001 Rivision 6 Group Inc. City of Snoqualmie/City of North Bend/King County Harper Righellis Inc. N/A October 2001 Revision 7 City of Snoqualmie Harper Righellis Inc. N/A April 2005 Revision 7 City of Issquah/King County Montgomery Water Group Inc. N/A August 2001 Revision 7 6 Contract Completion Community Contractor Number Date City of Issaquah/King County Concept Engineering Inc. N/A N/A Revision 7 King County NHC Inc. and King County N/A N/A Revision 8 Harper Righellis Inc. City of Renton NHC Inc. N/A June 2006 Revision 8 City of Duval NHC Inc. N/A June 2006 Revision 8 City of Bothell/ City of Kenmore/ City of Redmond/ City of Woodinville/ King County Revision 9 NHC Inc. * * King County NHC Inc. * * Revision 9 City of Burien/ City of Des Moines/ City of Federal Way/ City of Normandy Park/ City of Seattle/ City of Shoreline/ King NHC Inc. E00126E08 * *Data Not Available Base map information shown on the FIRM for Revision 9 was derived from multiple sources. Base map files were provided in digital format by King County GIS, WA DNR, WSDOT, and Pierce County GIS. This information was compiled at scales of 1:12,000 to 24,000 during the time period of 1994 – 2012. 1.3 Coordination The coordination for the original King County FIS was completed in multi-agency conferences managed by the FEMA Consultation and Coordination Officer (CCO). The State of Washington Department of Ecology provided input to establish the study priority and the contracting agency. The King County Division of Hydraulics offered valuable assistance to the USACE and the study contractor, in establishing the scope of the original study, coordinating basic data, and defining 7 approximate floodplain boundaries. Topographic maps at contour intervals of five feet, which served as part of the input for the hydraulic analysis and the location of the floodplain boundary lines, were supplied by the King County Department of Public Works. The county also provided information on certain elevation reference marks. Contacts with the private engineering firms of Bush Roed and Hitchings, Inc., of Seattle, and Horton Dennis and Associates, Inc., of Seattle, were made during the study to discuss field surveys they had conducted. Permission to enter restricted areas for field surveys was obtained from the City of Seattle and the Chicago, Milwaukee, St. Paul, and Pacific Railroad. The final CCO meeting was held at the offices of the King County Public Works Department on June 25, 1976. King County officials objected to the ―equal conveyance‖ floodways that were developed in accordance with FEMA guidelines, wanting to apply more stringent floodway criteria. They were especially concerned about the Snoqualmie River, fearing that the loss of valley storage would increase peak discharges if the fringe were filled. The initial coordination meeting for the original City of Auburn study was held on April 8, 1976. At this meeting, streams to be studied by detailed methods were identified by representatives of the community, the study contractor, and FEMA. During the course of the work, numerous informal contacts were made by the study contractor with the community for the purpose of obtaining data and base maps. On March 17, 1978, the results of the work were reviewed at an intermediate coordination meeting attended by representatives of the city, the study contractor, and FEMA. The results of the original study were reviewed at a final CCO meeting held on December 6, 1978. Attending the meeting were representatives of FEMA, the study contractor, and the city. This study incorporates all appropriate comments, and all problems have been resolved. The initial coordination meeting for the City of Bellevue study was held in April 1975. This meeting was attended by personnel of the U.S. Geological Survey (USGS), FEMA, and officials of the Bellevue Planning and Storm Drainage Utility Departments. Community base maps were selected and streams requiring detailed study were identified. A search for basic data was made at all levels of government. Topographic maps with a 5-foot contour interval were supplied by the 8 Bellevue city engineer; these served as preliminary work maps on determining the location of floodplain boundary lines. Some locations and elevations of bench marks were provided by the city and verified by USGS levels. During the course of the work by the USGS, flood elevations, floodplain boundaries, and floodway delineations were reviewed with community officials. On April 29, 1977, the results of the work by the USGS were reviewed at a final CCO meeting attended by personnel of the USGS, FEMA, and officials of the Bellevue Planning and Storm Drainage Utility Departments. The initial coordination meeting for the City of Carnation was held in the Carnation Town Hall on July 29, 1977. At the meeting, flooding sources for the City of Carnation were defined and the areas to be studied were identified. Representatives from the City of Carnation, CH2M Hill, Inc. (the study contractor), and FEMA attended the meeting. Throughout the study, coordination was maintained with the USACE, King County hydraulics division, town officials, Sammamish Valley newspaper, Carnation Planning Commission, and King County Planning Commission. All were contacted to provide information pertinent to this FIS. The results of the original study were reviewed at a final CCO meeting held on December 19, 1978. Attending the meeting were representatives of FEMA, the study contractor, and the city. No problems were raised at the meeting. The initial coordination meeting for the City of Des Moines was held on August 19, 1977. This meeting was attended by representatives of the study contractor, FEMA, and the city. This meeting was held to identify areas requiring detailed study and to familiarize city officials with all aspects of the study and to solicit pertinent information. The Des Moines city government; the Covenant Beach Bible Camp management; and King County Department of Public Works, Division of Hydraulics, were contracted for the coordination of this FIS. The results of the original study were reviewed at a final community coordination meeting held on March 26, 1979. Attending the meeting were representatives of FEMA, the study contractor, and the city. No problems were raised at the meeting. In 1981, the City of Des Moines annexed an area along Puget Sound south of the Des Moines Marina. A detailed wave runup analysis of this area 9 was completed in May 1984. An area west of Pacific Highway South (State Highway 99) between Kent-Des Moines Road and South 252nd Street has also been annexed by the City. The analysis to determine the extent of approximate floodplain boundaries in this area was completed in January 1985 and used to update this study. The initial coordination meeting for the City of Duvall was held in the Duvall City Hall on July 28, 1977. At the meeting, flooding sources for the City of Duvall were defined and the areas to be studied were identified. Representatives from the City of Duvall, the study contractor, and FEMA attended the meeting. The King County Department of Public Works, Division of Hydraulics; the Sammamish Valley News; and the Duvall Planning Commission were contracted for information pertinent to this FIS. The results of the original study were reviewed at a final community coordination meeting held on October 2, 1978. Attending the meeting were representatives of FEMA, the study contractor, and the city. No problems were raised at the meeting. The initial coordination meeting for the City of Issaquah was held on April 8, 1976. The identification of streams selected for detailed analysis was accomplished at this meeting which was attended by representatives of the community, the State of Washington Department of Ecology, FEMA, and a study contractor who was initially chosen to perform the study but did not finally participate. During the course of the work numerous informal contacts were made by Tudor Engineering Company personnel with the community for the purpose of obtaining information and confirming data. Previous work by the USACE was reviewed and forms the basis of this study. On January 27, 1977, the results of the work were reviewed at an intermediate coordination meeting attended by representatives of the City of Issaquah, Tudor Engineering Company, and FEMA. A final coordination meeting held on April 2, 1979, resulted in agreement by the same parties, and this report incorporates resolution of all comments received as a result of coordination activities. The initial coordination meeting for the original City of Kent study was held on April 8, 1976. Streams to be studied by detailed methods were identified at this meeting, which was attended by representatives of the City of Kent and FEMA. 10 During the course of work, the study contractor maintained contact with the USACE; the King County Division of Hydraulics; and the City of Kent, Department of Public Works. On May 29, 1979, the results of the study were reviewed at an intermediate coordination meeting attended by representatives of the City of Kent, the study contractor, and FEMA. The results of the original study were reviewed at a final community coordination meeting held on April 28, 1980. Attending the meeting were representatives of FEMA, the study contractor, and the city. No problems were raised at the meeting. On April 8, 1976, the initial coordination meeting for the City of Kirkland was held to determine streams to be studied by detailed analysis. This meeting was attended by representatives of the City, FEMA, and the study contractor who was originally chosen to perform the work but did not finally participate. During the course of the work, numerous informal contacts were made by the study contractor with the community for the purpose of obtaining data and base maps. On November 30, 1977, the results of the work were reviewed at an intermediate coordination meeting attended by representatives of the City of Kirkland, the study contractor, and FEMA. The results of the original study were reviewed at a final community coordination meeting held on May 12, 1980. Attending the meeting were representatives of FEMA, the study contractor, and the City. This study incorporates all appropriate comments, and all problems have been resolved. In August 1977, the initial coordination meeting for the City of Lake Forest Park was held. Streams requiring detailed and approximate study were identified at this meeting attended by representatives of the study contractor, FEMA, and the City of Lake Forest Park. Initial contact with the Lake Forest Park City Manager, who is also the Public Works Director, was made in February 1978. The City Manager provided background data in the community and descriptions of flood hazard areas in Lake Forest Park. The King County Public Works Department and the USGS were contacted to provide information pertinent to this Flood Insurance Study for Lake Forest Park. 11 The results of the original study were reviewed at a final community coordination meeting held on December 12, 1978. Attending the meeting were representatives of FEMA and the study contractor, as well as city officials and interested citizens. No problems were raised at the meeting. The initial coordination meeting for the City of Normandy Park was held on December 5, 1975. It was attended by representatives of the study contractor, FEMA, and officials of Normandy Park. This meeting was held to identify streams requiring detailed study, to familiarize city officials with all aspects of the study, and to solicit pertinent information. A search for basic data was made at all levels of government. The City of Normandy park, the King County Zoning and Plans Division, the King County Hydraulics Commission and CH2M HILL, Inc. provided maps and other data used in this study. On August 6, 1976, the results of the work effort by CH2M HILL Inc. were reviewed at the final CCO meeting attended by personnel of the study contractor, FEMA, and officials of the City of Normandy Park. The comments of the officials were incorporated and the study accepted. The initial coordination meeting for the City of North Bend was held on July 29, 1977. Streams requiring detailed study were identified at this meeting attended by representatives of the study contractor, FEMA, the State of Washington Department of Ecology, King County, and the City of North Bend. In March 1981, an approximate study was added to the scope of study as a result of consultation among representatives of FEMA, the City of North Bend, and the study contractor. The King County Engineering and Public Works Departments were contacted to discuss past flooding problems and to gather available topographic mapping and levee plans along with aerial photographs of recent flooding events. The USACE was also contacted to obtain recently developed hydrologic and hydraulic information pertinent to this Flood Insurance Study. The hydrology presented in this study was coordinated with USACE, the State of Washington Department of Ecology, and the King County Department of Public Works. On September 22, 1981, the results of the study were reviewed at an intermediate coordination meeting attended by representative of the City, the State of Washington Department of Ecology, FEMA, and the study contractor. No problems were raised at the meeting. 12 The final coordination meeting was held on September 13, 1982, and was attended by representatives of FEMA, the study contractor, and the City. No problems were raised at the meeting. The initial coordination meeting for the City of Pacific was held on August 1, 1977. Rivers and drainage ditches requiring detailed and approximate study were identified at this meeting attended by representatives of FEMA, the City, and the study contractor. The USACE, the USGS, the Washington State Department of Highways, Tudor Engineering, city officials, and local citizens provided information used in the report. The results of the study were reviewed at a final community coordination meeting held on December 3, 1979. Attending the meeting were representatives of FEMA, the study contractor, and the Pacific City Council and members of the public. As a result of this meeting, an area of moderate flood hazard was added to the map. An initial coordination meeting for the City of Redmond was held to identify streams requiring detailed study. This meeting was attended by representatives of the City of Redmond, FEMA, and the study contractor. Results of the hydrologic analyses were coordinated with the City of Redmond, FEMA, and Tudor Engineering Company. During the course of the work, numerous informal contacts were made by Tudor Engineering Company, which conducted the study, with community officials for the purpose of obtaining information and confirming data. Previous work by the USACE was reviewed and forms the basis of this study. The results of the study were reviewed at the final meeting attended by representatives of the study contractor, FEMA, and community officials. The study was acceptable to the community. The initial coordination meeting for the original City of Renton study was held on April 8, 1976. Streams selected for detailed analysis were identified at this meeting attended by representatives of the community, the original study contractor, and FEMA. On July 13, 1979, the results of the work were reviewed at an intermediate coordination meeting attended by representatives of the City, the study contractor, and FEMA. The results of this study were reviewed at a final community coordination meeting held on May 5, 1980. Attending the meeting were representatives 13 of FEMA, the study contractor, and the City. No problems were raised at the meeting. The initial coordination meeting for the Town of Skykomish was held on July 29, 1977. Streams requiring detailed and approximate study were identified at this meeting attended by representatives of the study contractor, FEMA, and the Town of Skykomish. Town officials provided background data on the community and descriptions of known flood hazard areas in Skykomish. The King County Public Works Department, the USACE, and the USGS were contacted for additional information to this Flood Insurance Study. The results of the original study were reviewed at a final community coordination meeting held on April 21, 1980. Attending the meeting were representatives of FEMA, the study contractor, and the town. This study incorporates all appropriate comments, and all problems have been resolved. The initial coordination meeting for the City of Snoqualmie was held on May 31, 1978. Streams requiring detailed study were identified at this meeting attended by representatives of the study contractor, FEMA, the USACE, and the City of Snoqualmie. A series of meetings was also attended by the city officials, FEMA, and study contractor representatives to discuss possible floodway alternatives. These meetings were held in March 1979, January 1981, and June 1981, and initially resulted in the selection of an equal conveyance floodway for the study. The requirement for expansion of the study to include additional detailed and approximate study mapping for and expected annexation to the city was discussed at the intermediate community coordination meeting held November 4, 1981, and attended by representatives of the study contractor, FEMA, and the City of Snoqualmie. At the final community coordination meeting held on August 1, 1983, city officials requested that an alternative negotiated floodway be considered that would more fully meet the city’s needs along with those of the adjacent country jurisdiction and ownerships. A negotiated floodway was developed for and approved by the City, King County, and affected county ownerships by written correspondence received during the period from October 1983 to January 1984. Results of the hydrologic analyses were coordinated with the USACE, the State of Washington Department of Ecology, and the King County Department of Public Works. 14 The initial coordination meeting for the City of Tukwila was held on April 8, 1976. Streams selected for detailed analysis were identified at this meeting attended by representatives of the community and FEMA. During the course of the work, numerous informal contacts were made by the study contractor with the community in order to obtain data and base maps. Data were also obtained from the USACE. On March 26, 1979, the results of the work were reviewed at an intermediate coordination meeting attended by representatives of the City, the study contractor, and FEMA. The results of the original study were reviewed at a final community coordination meeting held on December 10, 1979. Attending the meeting were representatives of FEMA, the study contractor, and the city. No problems were raised at the meeting. Initial community coordination meetings for the revised study for King County, Washington, and the Cities of Auburn, Kent, Renton, and Seattle, all within King County, were held on January 16, 1985, and January 24, 1985. At the January 16, 1985, meeting, representatives of FEMA, King County, the Cities of Auburn, Kent, and Renton, the Washington Department of Ecology, and the study contractor, CH2M HILL, Inc., identified streams requiring detailed and approximate study. Representatives of FEMA, the City of Seattle, and CH2M HILL, Inc., identified streams requiring detailed and approximate study at a meeting held on January 24, 1985. The purposes of the meetings were: (1) to inform the county on its status in the NFIP; (2) to identify existing flooding problems and available pertinent data on flooding in the county and cities, and (3) to reach an agreement on the areas to be studied. During the course of the study, numerous contacts were made and meetings held with local agencies and community officials to discuss and gather available data on flooding history, methods and preliminary results of analyses, and status of proposed near-term drainage system improvements for those flooding sources under study. The USGS was contacted and requested to provide available flow data and data analyses for the streams being studied and surrounding regional drainages. The USACE and the NRCS were also contacted and asked to provide any data or studies they had that were relevant to flooding caused by the streams under study. Correspondence with the Washington State Department of Transportation (WSDOT) pertained to proposed plans and timing of drainage structure improvements for Rolling Hills Creek and Springbrook Creek under Interstate Highway 405 (City of Renton). Information was also requested 15 for drainage improvements to State Route 522 and Northeast 195th Street, at their crossings of Little Bear Creek. The initial meeting was held with King County personnel to request available hydrologic and hydraulic information and accounts of flooding history for the flooding sources under study on December 5, 1985. King County Surface Water Management Division staff were contacted and asked to provide basin planning studies and information on any near-term planned drainage system improvements for the flooding sources under study. Design drawings for two bridges being constructed as part of Soos Creek Park on Big Soos Creek were made available through contacts with the King County Division of Parks and Recreation. The Surface Water Division’s maintenance personnel were asked to provide information on the operation of the P1 pumping station on Black River, and on the flooding history of the streams being studied. Storage floodway concepts for local drainages in the Green River Valley, including Mill Creek (Auburn), were discussed at meetings attended by representatives of King County, the Cities of Auburn and Kent, FEMA, and the study contractor, CH2M HILL, Inc. Preliminary results of analyses for the Green River and levee freeboard issues were presented and discussed at a public meeting on September 11, 1986, attended by representatives from King County, the City of Auburn, the City of Kent, FEMA, and CH2M HILL, Inc. City of Kent personnel were asked to provide data for a recent drainage basin study prepared for Mill Creek (Kent). Information on proposed drainage improvements for flooding sources under study in the Cities of Auburn, Kent, Renton, and Seattle were requested in the initial stages of study. Results of the hydrologic analyses were coordinated with community officials, the USACE, the NRCS, and the USGS. In March 1987, a coordination meeting for representatives of the USACE, Seattle District, and FEMA was held. An analysis of an upper reach of the Green River, immediately above the reach studied in the 1987 King County restudy, was identified. This study was performed under FEMA’s Limited Map Maintenance Program. The final community coordination meetings were held on December 6 and 7, 1988, and were attended by representatives of FEMA, the USACE, and the county. The study was acceptable to the county. 16 1.3.1 Revision 1 Miller Creek Various contacts for information regarding the addition of floodplain data for Miller Creek affecting the unincorporated areas of King County, Washington (Reference 94), and then incorporated Cities of Normandy Park (Reference 11) and SeaTac were made by the study contractor in October, November, and December 1990. Coordination with the regional project office and county and city officials, as well as local residents, produced a variety of information pertaining to flood history, available community maps, and other hydrologic data. 1.3.2 Revision 2 Snoqualmie River The CCO meeting was not held. 1.3.3 Revision 3 Raging River The initial CCO meeting was held on October 27, 1993, and was attended by representatives of FEMA, King County, and the consultant. 1.3.4 Revision 4 North Fork Issaquah Creek The initial coordination meeting to incorporate the results of detailed hydrologic and hydraulic analyses of North Fork Issaquah Creek in the City of Issaquah was held on October 20, 1994, and was attended by FEMA and nhc representatives. Various agencies contacted for information include: the City of Issaquah and King County Public Works Departments; WSDOT; and the USACE, Seattle District. Local residents and engineers for private developers provided information pertaining to flood history and recent and proposed basin development. Bear Creek & Evans Creek - The initial coordination meeting to incorporate the results of detailed hydrologic and hydraulic 17 analyses of Bear Creek and Evans Creek in the City of Redmond was held on October 20, 1994, and was attended by FEMA and nhc representatives. Various agencies contacted for information included: the WSDOT; City of Redmond Public Works Department; KCSWM; King County (Surface Water Management division) Engineering Department; and the USACE, Seattle District. The following engineering consultants, who performed previous hydraulic analyses of Bear Creek, were also contacted for information: CH2M HILL; Montgomery Water Group, Inc.; Alpha Engineering Group, Inc.; Land Tech; and Robert Parrott. In addition, local residents and business owners provided helpful information pertaining to previous flooding and development history along Bear Creek. Middle Fork Snoqualmie River - The CCO meeting was part of the public meeting hosted by King County on January 26, 1995; FEMA, King County, and the King County consultant (Harper Righellis, Inc.) provided presentations. South Fork Skykomish River - The initial CCO meeting was held on April 6, 1995, and attended by representatives of FEMA, the consultant (Harper Righellis Inc.), and the community. The information for this study supersedes the data presented for the South Fork Skykomish River through the Town of Skykomish. The Final CCO meeting was held with the Town of Skykomish on January 13, 1997, and attended by representatives of FEMA, King County, Town Council and the Washington Department of Ecology. Upper Middle Fork Snoqualmie River - The initial CCO meeting was held on January 24, 1995, and attended by representatives of King County, FEMA, and the consultant (Harper Righellis Inc.). North Fork Snoqualmie River and Tate Creek - The initial CCO meeting was held on November 13, 1995, and attended by representatives of King County, FEMA, and the consultant (Harper Righellis Inc.). South Fork Snoqualmie River - The initial CCO meeting was held on January 24, 1995, and attended by representatives of King County, FEMA, and the consultant (Harper Righellis Inc.). 18 1.3.5 Revision 5 The initial CCO meeting was held on September 21, 1993, and attended by representatives of FEMA and nhc. To acquire information for this revision, nhc contacted the Public Works Department of the City of Bothell; the Surface Water Management Division of Snohomish County; Montgomery Water Group, Inc.; Quadrant Company; Alderwood Water District; Bush, Roed and Hitchings; and the USACE. 1.3.6 Revision 6 Tolt River - A public meeting was held September 13, 1995, to present the proposed floodplain and floodway boundaries. Representatives of King County, the City of Carnation, the consultant, FEMA, and the USACE, Seattle District, attended the meeting along with about 70 residents. In addition to the September 13, 1995, meeting, there were several subsequent Carnation City Council meetings attended by FEMA and King County representatives and the county’s consultant (Harper Houf Righellis, Inc.). Also, there was a LOMR produced by FEMA on May 1, 2002, which entailed City Council meetings attended by FEMA and King County. Upper South Fork Snoqualmie study - A CCO meeting was held as part of the public meeting hosted by King County on February 4, 1997. The meeting was attended by the county’s consultant (Harper Houf Righellis, Inc.) and FEMA representatives. 1.3.7 Revision 7 Snoqualmie River - Revision 7 refers to the Lower Middle and Lower South Forks of the Snoqualmie, plus the Overflow channels in between. This mapping effort began in 1999 with an effort by the USACE as contracted by FEMA. The resultant FIRM dated June 30, 1999, was appealed by King County and the cities of North Bend and Snoqualmie. The USACE then produced a PFIRM dated August 8, 2000, which was also appealed. Then King County, serving on behalf of FEMA, utilized the county’s consultant (Harper Houf Righellis, Inc.) to revise the technical study. A technical coordination meeting hosted by King County and attended by the staff of the cities and FEMA was held on May 31, 2001. A City and Agency Coordination Meeting was held on September 26, 2001, and was hosted by King County with FEMA, 19 State, and city representatives in attendance. A public meeting held on November 14, 2001, was hosted by King County and the cities received presentations by the county’s consultant and FEMA representatives. The submitted study was approved, but BFEs on the subsequent PFIRM dated November 15, 2002, were incorrectly plotted. Therefore, FEMA reissued the PFIRM dated March 28, 2003. The Final CCO was held on June 16, 2003. This study became effective on April 19, 2005. Issaquah Creek - The scope of the re-mapping project for the flooding on Issaquah Creek was determined at meetings attended by representatives of the City of Issaquah, King County, and FEMA, on January 12 and March 28, 2000. The results of the restudy were reviewed at the final CCO meeting held on January 8, 2003. All problems raised at that meeting have been addressed in this restudy. 1.3.8 Revision 8 Patterson Creek - A study kickoff meeting was held October 27, 2005, and was attended by representatives of King County and nhc. The study was also coordinated by King County with the Patterson Creek Flood Control Zone District including a pre-study meeting on November 3, 2005, and a presentation meeting on June 22, 2006. Lower Snoqualmie River - Briefings by King County and its consultant, Northwest Hydraulic Consultants, Inc. (nhc), to City of Carnation staff and council members were provided on March 16, 2004, June 14, 2004, May 3, 2005, and January 3, 2006, with a public meeting hosted by King County on January 25, 2006, which included presentations by the consultant and representatives from FEMA and the Washington Department of Ecology. Springbrook Creek - No Information is available from the Springbrook CCO meeting. Cedar River - A public meeting was held on March 13, 2002 for the unincorporated King County portion of the Cedar River flood study, and attended by representatives from FEMA, King County, and the county’s consultant (Harper Houf Righellis, Inc.) Also, please note that the City of Renton requested a LOMR for the incorporated portion of the Cedar River. This LOMR was 20 reviewed and approved by FEMA on February 16, 2007, but FEMA could not issue a LOMR or physical map at that time. This LOMR is incorporated in the 2010 maps. Green River - This study was completed by nhc under contract to King County Department of Natural Resources and Parks (KCDNRP). The County is a Cooperating Technical Partner (CTP) with nhc for purposes of conducting FISs. However, this study was funded by King County and also received grant funding from the Washington State Department of Ecology through the Flood Control Assistance Account Program. King County provided project management and technical review of all study products. The County also supplied relevant study data including information on past watershed flooding. The study was started in September 2007 and an initial coordination meeting was held on September 27, 2007, with representatives of King County, nhc, the City of Auburn, the City of Kent, the City of Renton and the City of Tukwila. Additional technical coordination meetings were held with the County and City staff on December 6, 2007, January 10, 2008, February 11, 2008, and February 26, 2008. Ecology staff attended the February 26, 2008, meeting. Coordination meetings were also held with FEMA on November 20, 2007, and November 29, 2007. Draft floodplain data were delivered to FEMA Region X on March 18, 2008, along with a letter of appeal from King County and letters from each of the valley cities supporting the appeal. On September 23, 2009, FEMA’s technical reviewer, Michael Baker Jr., Inc. (Baker), provided King County with review comments and requests for clarification. Baker also provided FEMA Region X with a set of questions regarding how to proceed with finalizing the study. Nhc and King County met with FEMA Region X and submitted a coordinated response to all Baker comments on November 23, 2009. Nhc then worked with Baker to resolve any remaining issues related to the floodplain maps. Revised floodplain boundary delineations were submitted by nhc to FEMA and Baker on March 4, 2010, and the final floodway delineation was submitted on March 10, 2010. 1.3.9 Revision 9 Puget Sound - The study was completed by NHC under contract to KCDNRP, Water and Land Resources Division. The County is a CTP with FEMA for purposes of conducting FISs. King County provided project management and technical review of all study products and supplied relevant study data and coordination with 21 County citizens. The study was begun in December 2009, and an initial coordination meeting was held February 1, 2010, with representatives of King County, FEMA, STARR, and NHC. Additional technical coordination meetings were held with County staff at key milestones during the study process. Coordination also occurred with FEMA staff through meetings, emails and conference calls. King County, FEMA, and the contractor conducted public outreach by providing a kick-off presentation to representatives from the coastal Cities of Burien, Des Moines, Federal Way, Normandy Park, Seattle, and Shoreline, on January 13, 2011. Draft floodplain data were delivered by NHC to King County and presented at a public meeting on July 21, 2011. King County also conducted individual follow-up meetings with several cities including the City of Federal Way on August 10, 2011, and the City of Burien on August 22, 2011. Sammamish River – The study was completed by NHC under contract to KCDNRP. King County is a CTP with FEMA for purposes of conducting FISs. The County provided project management and technical review of all study products and also supplied relevant study data. The study was initiated in December 2008, and draft study products were presented to the Cities of Redmond, Woodinville, Bothell, and Kenmore on January 27, 2010. The meeting included presentations by representatives from NHC, FEMA, and the Washington State Department of Ecology. White River - This study was completed by NHC under contract to KCDNRP. King County is a CTP with FEMA for purposes of conducting FISs. The County provided project management and technical review of all study products and also supplied relevant study data including information on past White River flooding. The study was initiated on March 2007, and draft study products were presented to the public at a meeting in the City of Enumclaw on October 22, 2008. The public meeting included presentation by NHC, FEMA, and the Washington State Department of Ecology representatives. 2.0 AREA STUDIED 2.1 Scope of Study This FIS covers the geographic area of King County, Washington. Please note that the original scope was referring only to the June 1987 revised study and that only specific portions of King County were re-studied. 22 The areas studied by detailed methods were selected with priority given to all known flood hazard areas and areas of projected development or proposed construction through 1992. The following streams were studied by detailed methods in the April 19, 2005, revised countywide FIS: Raging River - From Interstate Highway 90 to 0.3 mile upstream of the second Upper Preston Road bridge Green River - From approximately 0.3 mile downstream of Pacific Highway to its confluence with Big Soos Creek Black River/ Springbrook Creek - From confluence with Green River to SW 16th Street Mill Creek (Auburn) - From confluence with the Green River to Highway 18 bridges at RM 6.2 Mill Creek (Kent) - From Highway 167 to limit of previous detailed study at the Earthworks Park stormwater detention facility outlet Big Soos Creek - From confluence with Covington Creek to SE 176th Street Swamp Creek - From confluence with the Sammamish River to northern King County boundary Little Bear Creek - From confluence with Sammamish River to northern King County boundary Bear/Evans Creek - From limit of previous detailed study at confluence with Cottage Creek to Paradise Lake Issaquah/Holder Creek - From limit of previous detailed study at SE May Valley Road to Highway 18 West Fork Issaquah Creek - From confluence with Issaquah Creek to SE 128th Way 23 May Creek - From Coal Creek Parkway bridge to SE 109 Place May Creek Tributary - From confluence with May Creek to 188th Avenue SE Cedar River - From Lake Washington to approximately RM 2.1 North and South Forks of Thornton Creek - From confluence with Lake Washington to Interstate Highway 5 Longfellow Creek - From SW Brandon Street to SW Thistle Street Rolling Hills Creek - Between first and second crossing of Interstate Highway 405 The Middle Green River was studied by detailed methods in the USACE February 1988 report from its confluence with Big Soos Creek to Flaming Geyser Bridge. The Tolt River was studied by detailed methods in the SCS June 1982 study from approximately 6,300 feet upstream of the Chicago, Milwaukee, St. Paul & Pacific Railroad to 5.5 miles upstream of the Railroad, a reach of 4.3 miles. The following streams studied by detailed methods were taken directly from previous Flood Insurance Studies covering King County and incorporated areas (Reference 1 to 18). Snoqualmie River - From the Snohomish County line to confluence with the Middle Fork Snoqualmie River, a reach of approximately 45 miles Middle Fork Snoqualmie River - From a point approximately 2,323 feet downstream of SE 428th Avenue to a point approximately 2,323 feet upstream of Mount Si Road, a reach of 3.37 miles 24 North Fork Snoqualmie River - From confluence with the Snoqualmie River to a point approximately 5,914 feet upstream of 428th Avenue SE, a reach of 1.5 miles South Fork Snoqualmie River - From confluence with the Snoqualmie River to a point approximately 8,000 feet downstream of 436th Avenue SE, a reach of 3.8 miles. (Note: A portion of the South Fork Snoqualmie River just upstream of the above-referenced detailed study reach is now depicted as approximate 1-percent- annual-chance flooding. This change was made because updated analysis along that reach superseded the detailed analysis and elevations shown on the effective county map (Reference 1)). Green River - From its mouth to confluence with Black River and from Flaming Geyser Bridge to a point approximately 7,286 feet upstream of Whitney Road Springbrook Creek - From SW 16th Street to a point approximately 1,690 feet upstream of South 228th Street, a reach of 6.32 miles Mill Creek (Auburn) - From State Highway 18 to a point 845 feet upstream of 15th Street SW, a reach of 0.72 miles Mill Creek (Kent) - From its mouth to State Highway 167, a reach of 4.24 miles White River - From a point approximately 4,330 feet downstream of Burlington Northern Railroad to the Muckleshoot Indian Reservation, a reach of 3.38 miles White River (Left Bank Overflow) - From confluence with the White River to the Muckleshoot Indian Reservation, a reach of 0.70 miles 25 Sammamish River - From its mouth at Lake Washington to the mouth of Lake Sammamish, a reach of 15.3 miles North Creek - From its mouth to a point approximately 10 feet upstream of NE 205th Street at the corporate limits of Bothell, a reach of 1.45 miles Bear Creek - From confluence with the Sammamish River to confluence with Cottage Lake Creek, a reach of 5.35 miles Evans Creek - From confluence with Bear Creek to a point approximately 2,059 feet upstream of 220th Avenue NE, a reach of 4.66 miles Issaquah Creek - From its mouth at Lake Sammamish to Southeast May Valley Road, a reach of 8.0 miles North Fork Issaquah Creek - From confluence with Issaquah Creek to a point approximately 740 feet upstream of Issaquah Avenue North, a reach of 0.95 miles East Fork Issaquah Creek - From confluence with Issaquah Creek to a point approximately 1,711 feet upstream of 3rd Avenue NE, a reach of 0.87 miles Tibbetts Creek - From its mouth to a point approximately 4,610 feet upstream of State Highway 900, a reach of 2.3 miles May Creek - From Barbee Mill Road to a point approximately 2,535 feet upstream of NE 31st Street, a reach of 2.02 miles Vasa Creek - From the corporate limits of the City of Bellevue approximately 2,500 feet upstream from its mouth to a point approximately 225 feet upstream 26 Cedar River - From a point approximately 2,629 feet upstream of Interstate Highway 405 to a point approximately 7,920 feet upstream of the Chicago, Milwaukee, St. Paul and Pacific Railroad, a reach of approximately 19 miles Mercer Creek - From its mouth to the confluence of Kelsey Creek and Richards Creek, a reach of 12.9 miles Mercer Creek Right Channel - Its entire length, a reach of approximately 1.0 mile Richards Creek - From confluence with Mercer Creek to a point approximately 380 feet upstream of SE Allen Road, a reach of 2.65 miles Richards Creek West Tributary - From confluence with Richards Creek to a point approximately 310 feet upstream of SE 32nd Street, a reach of 3.22 miles Richards Creek East Tributary - From confluence with Richards Creek to a point approximately 680 feet upstream of SE 26th Street, a reach of 0.24 miles Kelsey Creek - From its mouth to a point approximately 760 feet upstream of SE 16th Street, a reach of 5.08 miles West Tributary Kelsey Creek - From confluence with Kelsey Creek to Redmond Bellevue Road, a reach of 1.57 miles East Branch of West Tributary Kelsey Creek - From confluence with West Tributary Kelsey Creek to a point approximately 842 feet upstream of 137th Avenue NE, a reach of 0.44 miles 27 North Branch Mercer Creek (North Valley) - From confluence with Kelsey Creek to a point approximately 4,862 feet upstream of NE 24th Street, a reach of 1.49 miles McAleer Creek - From a point approximately 40 feet upstream of Bothell Way NE to a point approximately 3,340 feet upstream of NE 185th Street, a reach of 2.13 miles Coal Creek - From its mouth to the City of Bellevue corporate limits at Interstate Highway 405 and from the City of Bellevue corporate limits 8,250 feet upstream of Interstate Highway 405 to a point 9,690 feet upstream of Interstate Highway 405, a total length of 0.95 miles Forbes Creek - From the City of Kirkland corporate limits approximately 1,420 feet upstream from its mouth to a point approximately 496 feet upstream of NE 108th Street, a reach of 5.66 miles Lyon Creek - From confluence with Lake Washington to 35th Avenue NE and from a point approximately 80 feet downstream of Ballinger Road to a point approximately 760 feet upstream of Ballinger Road, a total distance of 1.42 miles Yarrow Creek - From 116th Avenue NE to a point approximately 1,515 feet upstream of NE 34th Street, a reach of 0.36 mile Meydenbauer Creek - From its mouth to a point approximately 520 feet upstream of 102nd Avenue SE, a reach of 0.36 miles North Fork Meydenbauer Creek - From confluence with Meydenbauer Creek to a point approximately 830 feet upstream 28 South Fork Skykomish River - From a point approximately 1,505 feet downstream of 5th Street to a point approximately 2,693 feet upstream of 5th Street, a reach of 0.8 miles Maloney Creek - From a point approximately 100 feet downstream of Burlington Northern Railroad to a point approximately 890 feet upstream of NE Old Cascade Highway, a reach of 0.32 miles Miller Creek - From its mouth to a point approximately 2,530 feet upstream of 12th Avenue SW, a reach of 0.86 miles Walker Creek - From confluence with Miller Creek to a point approximately 600 feet upstream of 12th Avenue SW, a reach of 0.33 mile Des Moines Creek - From its mouth at Puget Sound to a point approximately 1,960 feet upstream Unnamed Drainageway - The ponding of an unnamed drainageway in the central business district in the City of Kirkland, between Central Way and Kirkland Way Approximate analyses were used to study those areas having a low development potential or minimal flood hazards. The scope and methods of study were proposed to, and agreed upon by, FEMA and the community. 2.1.1 Revision 1 – Miller Creek Detailed methods were used to study 4.0 miles of the study reach extending from Puget Sound upstream to the proposed King County Lake Reba detention facility near State Route 518. Approximate methods were used to study the 0.4-mile-long Tub Lake Tributary located just upstream of the proposed detention facility. This minor channel is dry except during flood events. 29 2.1.2 Revision 2 – Snoqualmie River This revision was done to update the BFE placements shown on the Snoqualmie River from approximately 1,530 feet upstream of State Highway 202 to its confluence with the South Fork Snoqualmie River to match those shown on the published profiles for that reach. 2.1.3 Revision 3 – Raging River The revised analysis for the study reach of the Raging River from its confluence with the Snoqualmie River to approximately 0.6 miles upstream of Interstate 90 (I-90) (Downstream Reach) was performed by Harper Righellis, Inc. The revised analyses for the reach from approximately 0.6 mile upstream of I-90 to approximately 0.3 mile upstream of the second Upper Preston Road bridge (upstream reach) were performed by FEMA. Prior to this revision, the reach of the Raging River from its confluence with the Snoqualmie River to I-90 had not been studied in detail and appeared as an approximate Zone A on the maps. The reach from I-90 to approximately 0.3 miles upstream of the second Upper Preston Road bridge was studied by detailed methods prior to this revision and appeared as Zone AE on the FIRM. 2.1.4 Revision 4 North Fork Issaquah Creek - The study reach extends approximately 1.2 miles, beginning at the confluence with Issaquah Creek and ending at 230th Avenue SE. The study reach of North Fork Issaquah Creek is primarily located in the unincorporated areas of King County, but includes a very short segment that passes through the City of Issaquah at the I-90 interchange. Bear Creek & Evans Creek - The restudy covers riverine flooding on approximately 4.6 miles of Bear Creek, a tributary to the Sammamish River. The restudy reach extends from approximately 5,000 feet upstream of the mouth at the Sammamish River, at State Route 202, to approximately 250 feet upstream of the confluence of Bear and Cottage Lake Creeks at Avondale Road NE. 30 The restudy of Evans Creek included detailed hydraulic modeling from its mouth at Bear Creek upstream to River Mile 0.74. South Fork Skykomish - This study revises the detailed analyses of the South Fork Skykomish River through the Town of Skykomish and incorporates new detailed analyses affecting King County for reaches extending downstream and upstream of Skykomish. The study area begins at the county line for Snohomish and King Counties and extends 13 miles upstream nearly to the confluence of the Tye and Foss Rivers. Middle Fork Snoqualmie River - This study includes detailed analyses of a 3.9-river-mile reach of the Middle Fork Snoqualmie River and revises detailed analyses and includes new detailed analysis affecting King County. The study area begins 0.35 miles downstream of the Mount Si Road bridge. North Fork Snoqualmie River - This study includes detailed analyses for the North Fork Snoqualmie River upstream from its mouth for a distance of 2.41 miles affecting King County, revising previous effective detailed analyses, and adding new detailed analyses in the upstream reaches of the study area. Tate Creek - The Tate Creek study covers 1.6 miles of creek. The approximate analyses based on a range of calculated peak flows were used to determine typical flow depths and widths for various cross sections. 2.1.5 Revision 5 North Creek - The reach of North Creek that was studied for this revision extends approximately 1,000 feet upstream from the North Creek Parkway to the King-Snohomish County line at 205th Street. Two small streams were identified for study by approximate methods: Horse Creek was studied from confluence with the Sammamish River to the Bothell corporate limits. An unnamed creek that flows north along 96th Avenue Northeast from the Sammamish River for approximately 0.5 mile upstream. North Creek LOMR - This study has also been revised to incorporate LOMRs issued on March 3, 1995 (Case Nos. 94-10- 31 053P and 94-10-067P), and July 5, 1995 (Case No. 95-10-41P). The March 3, 1995, LOMR revised FIRM Panel 0007 C, dated March 2, 1994, to show the effects of a private flood protection system along North Creek from just upstream of I-405 to just downstream of Monte Ville Parkway. 2.1.6 Revision 6 Tolt River - This restudy revises the detailed analysis of Tolt River from the confluence with Snoqualmie River through the Town of Carnation and the unincorporated areas of King County to approximately 6.5 miles upstream of the confluence. Upper South Fork Snoqualmie River - This study was completed by King County and its consultant (Harper Houf Righellis, Inc.). The county study extends over a reach including approximately 4.9 miles of the Upper South Fork extending from the I-90 bridge crossing near the City of North Bend to above the bridge crossing at 468th Avenue. 2.1.7 Revision 7 Snoqualmie River - This restudy covers the Snoqualmie River main stem, South Fork, and Middle Fork of the Snoqualmie River, including overflows from Middle Fork, Ribary Creek, and Gardiner Creek. The Snoqualmie River detailed study covers a reach of approximately 10 miles. The main stem Snoqualmie River study starts at the Meadowbrook bridge and extends upstream 1.5 miles to the confluence of Middle Fork and South Fork. The Middle Fork study reach extends 3.4 miles, starting from the confluence with South Fork, upstream to the Mt. Si Road bridge. The South Fork study reach extends 5.0 miles starting from the confluence with Middle Fork, upstream to the I-90 bridges (Reference 129). Issaquah Creek - The Issaquah Creek detailed study reaches cover approximately 6.3 miles. Issaquah Creek was studied from the northern corporate limit of the City of Issaquah in Lake Sammamish State Park, to the southern corporate limit, for a reach of approximately 4.7 miles. East Fork Issaquah Creek (East Fork) was studied from the confluence with Issaquah Creek upstream approximately 1.0 mile to I-90. The Gilman Boulevard Overflow of Issaquah Creek was studied from the point of overflow from Issaquah Creek to its confluence with Tributary 0170 approximately 0.6 miles downstream. 32 2.1.8 Revision 8 Cedar River –Within the Area of City of Renton - This detailed study includes flooding along the Cedar River within the City of Renton. The study reach begins at the river outlet at Lake Washington and extends 5.36 miles upstream to the City of Renton limits at 149th Avenue SE. Cedar River – Unincorporated Area of King County - This detail study covers 17 miles of Cedar River, beginning at 149th Avenue SE and extends to the Landsburg Road bridge crossing in the unincorporated area of King County. Kelsey Creek - The Kelsey Creek study reach LOMR begins at the crossing with I-405 at river mile (RM) 0.0 and continues approximately 4.4 miles upstream near the intersection of 148th Avenue NE and NE 6th Street. The West Tributary study reach begins at the confluence with Kelsey Creek east of the Lake Hills Connector and continues upstream for 0.80 miles. Kelsey Creek and the West Tributary are located within the City of Bellevue, and are part of the Lake Washington watershed. The headwaters of Kelsey Creek originate in the highlands area of Bellevue near Phantom Lake. From there the stream follows a north- northwesterly course approximately 1.8 miles through several pond and marsh areas before reaching the upper extent of the current study reach. The study reach begins flowing north along 148th Avenue NE, but quickly turns northwest and eventually west and south as the stream flows through alternating residential, commercial, and vegetated corridors. The stream continues southward, flowing through the Glendale Golf Course and Kelsey Creek Park before turning west and joining the West Tributary in a broad wetland area located to the east of the Lake Hills Connector. Between the north and southbound lanes of the Lake Hills Connector is the confluence of Kelsey and Richards Creeks. Downstream of the confluence, Kelsey Creek flows through a wetland area followed by an entrenched vegetated corridor until reaching the I-405 culvert. Downstream of I-405, Kelsey Creek flows into Mercer Slough, and finally Lake Washington. Patterson Creek - This floodplain mapping study comprises an investigation of riverine flooding on Patterson Creek in King County, Washington. The detailed study reach includes approximately 8.3 miles of Patterson Creek starting approximately 0.9 miles upstream of the confluence with the Snoqualmie River and extending to approximately RM 9.2. Snoqualmie River - The nhc study completed in April 2006 includes the lower 39 miles of the Snoqualmie River. The 33 downstream mapping limit of the study is the State Route 522 Bridge crossing over the Snohomish River, approximately 1 river mile downstream of the confluence of the Snoqualmie and Skykomish Rivers. The upstream mapping limit on the Snoqualmie River is at the base of Snoqualmie Falls just downstream of the City of Snoqualmie, approximately 39 river miles upstream of the confluence with the Skykomish River. The study limit within King County includes 33.5 miles of river reach beginning at the King County boundary to just downstream of Snoqualmie Falls. Springbrook Creek – This detailed floodplain mapping study along the Springbrook Creek starts from the Black River pumping station to SW 23rd Street (also known as 180th Street) at the Renton and Kent city boundary. The study covers 16,935 feet of Springbrook Creek and 2,492 feet of the SW 23rd Street drainage canal. Green River - There are two separate studies performed for the Green River. These studies are called Lower Green River and Middle Green River for the purposes of these studies. The Lower Green River detailed study covers approximately 29.5 miles from boundary between the City of Seattle and City of Tukwila and Unincorporated King County near RM 3.85 and extending to State Highway 18 Bridge. Lower Green River study extends from RM 3.85 to RM 33.3. The Middle Green River detailed study reach includes approximately 12.1 miles of the Green River, starting at the downstream side of the State Highway 18 Bridge and extending to near the upstream end of Flaming Geyser State Park. 2.1.9 Revision 9 Puget Sound - This floodplain mapping study comprised the entire incorporated coastline of Puget Sound in King County, Washington. Backwater effects were adjusted on Des Moines Creek, Miller Creek, and Walker Creek. Sammamish River – This floodplain mapping study comprises an investigation of riverine flooding on the Sammamish River in King County, Washington. The study area covers the entire Sammamish River, beginning at the source at Lake Sammamish and extending approximately 14 miles upstream to Lake Washington. The work was performed using detailed hydrologic and hydraulic analysis methods approved by FEMA (Reference 190). Also backwater 34 effects from Sammamish River on Bear Creek, North Creek Little Bear Creek, and Swamp Creek were updated. White River – This floodplain mapping study comprised an investigation of riverine flooding on the White River in King County, Washington. The area of study covers approximately 6.6 miles of the White River, beginning downstream of the State Highway 410 Bridge at RM 22.0 and extending to the outlet works of Mud Mountain Dam at RM 28.6. The work was performed using detailed hydrologic and hydraulic methods approved by FEMA. The following tabulation presents Letters of Map Change (LOMCs) incorporated into this countywide study: LOMC Case Number Date Issued Project Identifier LOMR* 03-10-0047P 1/22/2004 University of Washington LOMR* 08-10-0762P 03/08/2010 Stage 2- Bear Creek Overflow LOMR* 11-10-0014P 03/24/2011 North Creek CLOMR, King/ Snohomish County Washington LOMR* 11-10-1517P 08/17/2012 South Route 202 Widening Project- Evans Creek *Letter of Map Revision (LOMR) 2.2 Community Description King County, located in western Washington, is the largest center of population and economic growth in the State of Washington. Its eastern boundary is along the divide of the rugged Cascade Range, and is bordered on the west by Puget Sound. Contiguous counties related economically, as well as geographically to King County are Kitsap County to the west, Chelan and Kititas Counties to the east, Snohomish County to the north, and Pierce County to the south. The City of Seattle is the county seat and the largest city in Washington. It is located between Puget Sound and Lake Washington. Seattle is important as a port for foreign trade with Asian and South American countries as well as for domestic shipping with Alaska. The 2010 35 estimated population of Seattle was 608,660 (Reference 183). The area within the Seattle corporate limits is currently 83.9 square miles. The City of Auburn is located south of Kent. It is approximately five miles from the shores of Puget Sound and 24 miles south of Seattle. Auburn is bordered by Pierce County to the south and by the Cities of Algona and Pacific to the southwest. Auburn has a community area of approximately 30 square miles, and had a population of 70,180 in 2010 (Reference 183). The City of Bellevue is located in northwest-central King County, eight miles east of Seattle. Bellevue, Washington’s fourth largest city, had a population of 122,363 in 2010 (Reference 183). The City of Black Diamond is located in south-central King County. The city had a population of 4,151 in 2006 (Reference 183). The City of Bothell was incorporated in 1909 and is located approximately 12 miles northeast of Seattle. The City of Bothell lies within two counties, King and Snohomish. The city is bordered by the City of Kenmore, City of Woodinville, City of Lake Forest Park, City of Mill Creek, and the City of Kirkland. The estimated 2010 population in the City of Bothell was 33,505 (Reference 183). The City of Burien was incorporated in 1993 and is located 10 miles south of Seattle. The City of Burien covers 7.4 square miles and is bordered on the west by several miles of scenic Puget Sound shoreline, stretching north to downtown Seattle. The small residential communities of Normandy Park and Des Moines are its neighbors to the south. The estimated 2010 population of the City of Burien was 33,313 (Reference 183). The City of Carnation, incorporated in 1912, is located in north-central King County, on the east bank of the Snoqualmie River. It is approximately 20 miles east of Seattle. The estimated 2010 population in the City of Carnation was 1,786 (Reference 183). The City of Covington was incorporated in 1997 and is located in the southeastern portion of King County close to the Puget Sound and with views of Mount Rainier. Covington is easily accessible from Highway 18 and State Route 516. The estimated 2010 population in the City of Covington was 17,575 (Reference 183) in an area of 6.5 square miles. The City is bordered by the City of Kent on the western side, the City of Maple Valley to the east and King County to the north and south. The City of Des Moines, incorporated in 1959, is located in west-central King County. It is just south of the City of Normandy Park and southwest of the Seattle-Tacoma Airport. It is situated in one of the few areas in 36 southern King County along Puget Sound where the land slopes gently down toward the water. The estimated 2010 population in the City of Des Moines was 29,673 (Reference 183). The City of Duvall, incorporated in 1913, is located on State Highway 203, on the east bank of the Snoqualmie River, in northwestern King County. It is approximately three miles from the Snohomish County line and seven miles north of Carnation. The city had a population of 6,695 in 2010 (Reference 183). The City of Enumclaw is located in south-central King County, near the Pierce County line. Enumclaw had a population of 10,669 in 2010 (Reference 183). The City of Federal Way is located 25 miles south of downtown Seattle and just eight miles north of downtown Tacoma. Federal Way has eight miles of Puget Sound waterfront and is in the southwestern corner of King County. The estimated 2010 population in the City of Federal Way was 89,306. (Reference 183) The City was incorporated in February of 1990. The City of Issaquah is located in west-central King County, approximately 14 miles east of downtown Seattle. The City had a population of 30,434 in 2010 (Reference 183). The City of Kenmore is located on the north side of Lake Washington, in the northern part of King County. The estimated 2010 population in the City of Kenmore was 20,460 (Reference 183) in an area of 6.1 square miles. Kenmore is bordered by the City of Lake Forest Park, City of Bothell, and City of Brier. On August, 31, 1998, Kenmore was incorporated, making it the newest city in King County. The City of Kent is located south of Renton and is within two to five miles of the shores of Puget Sound. The City of Tukwila is northwest of Kent and the City of Des Moines is to the west. Kent had a population of 92,411 in 2010 (Reference 183) and occupies an area of approximately 17 square miles. Most of Kent lies on the 2-mile-wide low-lying valley east of the Green River. The bluff area along the east boundary of Kent is drained by several creeks, including Mill, Springbrook, and Garrison Creeks. The City of Kirkland is located on the east shore of Lake Washington, off Interstate 405 in northern King county. Kirkland is 10 miles east of downtown Seattle, west of Redmond, and just north of Bellevue. The City was founded in 1888 and incorporated in 1905. The estimated 2010 population was 48,787 (Reference 183) - in an area of 11 square miles. The City is bordered by the City of Redmond on the East, City of Bellevue 37 and Yarrow Point on the South, and King County on the Western and Northern borders. The City of Lake Forest Park is located in the Puget Sound region of northwest Washington in northwestern King County. The community is part of the suburban area that surrounds the Seattle metropolitan center. Lake Forest Park had a population of 12,598 in 2010 (Reference 183). The City of Maple Valley incorporated August 31, 1997. The City is 5.8 square miles, located east of Kent and Covington, and north of Black Diamond. The estimated 2010 population was 22,684 (Reference 183). The City of Medina is located in the Eastside region of King County, Washington. Opposite Seattle, and surrounded on the north, west, and south by Lake Washington, Medina is bordered by Clyde Hill and Hunts Point, as well as the satellite city of Bellevue. The estimated 2010 population was 2,969 (Reference 183). According to the United States Census Bureau, the city has a total area of 4.8 square miles, with 1.4 square miles of land and 3.3 square miles of water. The City of Mercer Island incorporated on July 5, 1960. It included all the land area of the island with the exception of the 70 acre (280,000 m²) business district. Just over a month later, on August 9, the business district incorporated as the Town of Mercer Island, wholly surrounded by the City. The two municipalities finally merged on May 19, 1970. According to the United States Census Bureau, the City has a total area of 13.1 square miles, with 6.4 square miles of land and 6.7 square miles of water. Mercer Island is connected to Seattle in the west by Interstate 90, carried by the Homer M. Hadley Memorial Bridge (the fifth longest floating bridge in the world) and the Lacey V. Murrow Memorial Bridge (the second longest in the world). I-90 also connects Mercer Island to Bellevue in the east, over the East Channel Bridge. The estimated 2010 population in the City of Mercer Island was 22,699 (Reference 183). The Muckleshoot Indian Reservation was established in 1857. The reservation is located within the area of Auburn, Washington, located between the White and Green rivers. The Muckleshoot Indian Reservation has a total area of 6.1 square miles (Reference 183). The City of Newcastle is located 12 miles east of city of Seattle, bordering to the north is Bellevue, and to the south is Renton. The City was incorporated on September 30, 1994. According to the United States Census Bureau, the City has a total area of 4.5 square miles, and 0.22 percent is water. The estimated 2010 population was 10,380 (Reference 183). 38 The City of Normandy Park is located on Puget Sound in southwestern King County. It is located west of the Seattle-Tacoma Airport and due south to Burien Lake. Normandy Park had a population of 6,335 in 2010 (Reference 183). The City of North Bend is located in central King County. It lies in the foothills of the Cascade Mountains, approximately 25 miles east of Seattle along Interstate Highway 90. The City of North Bend had a population of 4,621 in 2010 (Reference 183). The City of Pacific is located in southwestern King County. It shares common boundaries with the City of Algona to the north and Pierce County to the south. The City of Pacific had a population of 5,859 in 2010 (Reference 183). The City of Redmond lies in northwest-central King County. It is approximately 10 miles northeast of downtown Seattle. Redmond had a population of 54,144 in 2010 (Reference 183). The City of Renton is located in western King County. It is located approximately 11 miles southeast of Seattle just north of Kent and just east of Tukwila. Renton had a population of 58,534 in 2006 (Reference 183). The City of Sammamish is an Eastside suburb, 19 miles east of Seattle, in King County. It was incorporated in 1999. The estimated 2010 population was 45,780. (Reference 183) Neighboring cities include Redmond to the north and Issaquah to the south. According to the United States Census Bureau, the city has a total area of 18.3 square miles. The City of SeaTac is an outlying suburb of Seattle, located in the southern section of King County. The estimated 2010 population was 26,909. (Reference 183) SeaTac was officially incorporated on February 28, 1990. According to the United States Census Bureau, the city has a total area of 10.1 square miles; 10 square miles of land and 0.1 square miles of water. The City of Shoreline is located in Western Washington, 15 miles north of downtown Seattle. Shoreline was incorporated 1995, and is surrounded by the older cities of Seattle, Edmonds, Woodway and Lake Forest Park. Covering 11.74 square miles, Shoreline is Washington's 15th largest city. The estimated 2010 population was 53,007 (Reference 183). The Town of Skykomish is located in northwestern King County. It is in a narrow valley along the south side of the South Fork Skykomish River and 39 is surrounded by the Snoqualmie National Forest. Skykomish had a population of 198 in 2010 (Reference 183). The City of Snoqualmie is located in central King County. The City lies near the foothills of the Cascade Mountains, approximately 25 miles east of Seattle along I-90. Snoqualmie had a population of 10,670 in 2010 (Reference 183). The City of Tukwila is located in west-central King County. It is northwest of Kent and west of Renton. It is approximately 12 miles south of Seattle and 22 miles northwest of Tacoma. Tukwila had a population of 19,107 in 2010 (Reference 183). The City of Woodinville is located in northern King County east of the Bothell. As of the 2010 census, the city had a total population of 10,938. Woodinville was officially incorporated on March 31, 1993. According to the United States Census Bureau, the city has a total area of 5.7 square miles; 5.6 square miles of land and 0.04 square miles of water. The population of King County was 1,931,722 as of 2010, with 341,000 residing in the unincorporated areas, mostly surrounding the large population center of Seattle. In most suburban communities and unincorporated areas of west-central King County, a decline in farming and significant transition to residential and industrial/commercial development has occurred. Urbanization has spread up the Green and Cedar River valleys where urban build up now covers more than one- fourth of the basin’s land areas. The Sammamish River valley is another site of increased residential and industrial/commercial uses. The Snoqualmie River valley is presently the county’s primary district for farming and the dairy industry, but urbanization pressures exist for conversion of those agricultural lands to higher value, more intensive land use. The climate of King County is predominately a mid-latitude, west coast, marine type. Most of the air masses that reach the Puget Sound area originate over the Pacific Ocean. In late fall and winter these masses are moist and about the same temperature as the ocean surface. Orographic effects caused by lifting and cooling of air masses moving inland results in a wide range of precipitation patterns over King County. Fifty percent of the annual precipitation typically occurs in the four month period of October through January, and 75 percent occurs in the six months from October through March. Below 1,500 feet in elevation, the winter precipitation normally falls as rain, occasionally interrupted by periods of snow. During the warmest summer months, the average afternoon temperatures over the county’s Puget Sound lowlands are in the lower 70s, 40 decreasing into the 60s in the mountains. Temperatures reach 85°F to 90°F about 5 to 15 days per year, and extremes up to 100°F have occurred in the lower valleys. In winter, afternoon temperatures over the lowland typically range from 35°F to 45°F. The Japanese Current generally moderates the temperatures of winter, but almost every winter there are a few nights when the temperatures range from 10°F to 20°F, with extremes to 0°F. All of the watersheds in King County are free from glaciers, unlike many streams in other counties lying between the Cascades and Puget Sound. The undisturbed land cover in King County is dominated by dense conifer forests, with some grass covered prairie-like areas in the lowlands. However, those lowland areas are interspersed with scattered stands of Douglas fir and Oregon white oak. Scotchbroom and other shrubs and seasonal groundcover are typical of those areas. Fresh water marshes commonly have cover consisting of cattails, rushes, and sedges. Big leaf maple trees and red alder are very common between the foothills and Puget Sound. The Sammamish River is located in northwest King County between Lake Sammamish and Lake Washington. The channel begins at the outlet from Lake Sammamish at the north end of the lake in Marymoor Park. The river then flows northward through unincorporated King County and the Cities of Redmond and Woodinville. At the City of Woodinville, the channel turns to the west, flowing through the Cities of Bothell and Kenmore, before it terminates at Lake Washington. A significant portion of the river valley between the Cities of Redmond and Woodinville are in King County’s Farmland Preservation Program and have stringent deed restrictions protecting agricultural uses and prohibiting other development. Much of the rest of the watershed within the study area, as well as the catchment areas upstream, has been developed for residential, commercial, and industrial uses. Consequently, runoff from precipitation events is higher than in times prior to development. Inflow to the Sammamish River is largely uncontrolled with the exception of discharges from Lake Sammamish which are controlled by an in- channel weir. This weir is located near the upstream end of the Sammamish River at river mile (RM) 13.3 and was built by the USACE in 1966 as part of a channel improvement project. The purpose of that project was to provide protection against spring floods with a 10-percent- annual-chance of occurrence without causing Lake Sammamish to rise higher than an elevation of 32.6 feet NAVD88 (29.0 feet NGVD29). The project included deepening the river, by approximately 5 feet throughout most of its length, and widening the channel, with the excavated material being placed on the river banks (Reference 1). The weir was modified in 41 1998 to repair degradation of the structure due to wear and to improve fish passage. Several tributaries contribute flow to the Sammamish River within the study area. The largest tributaries by area downstream of Lake Sammamish are (Big) Bear Creek at RM 12.3, Little Bear Creek at RM 5.4, North Creek at RM 4.4, and Swamp Creek at RM 0.75. There are numerous other small named and unnamed creeks, drainage ditches, and storm drain outfalls that discharge to the Sammamish River between Lake Sammamish and Lake Washington. White River is located near the Cities of Enumclaw and Buckley, where the river flows in a relatively straight west-northwesterly path from Mud Mountain Dam until it crosses under the SR 410 Bridge. Much of the watershed upstream of the study area has seen only limited development and land cover in the watershed remains dominated by forest. There are, however, some small pockets of residential development within the study reach. Flows in the study reach are controlled to a large extent by upstream flood management operations at the USACE Mud Mountain Dam located at RM 28.9. Two significant tributaries contribute flow to the White River. These are Red Creek, which enters the White River at RM 26.8, and Boise Creek which enters at RM 22.6. Numerous other named and unnamed tributaries and ditches contribute flow to the White River. A diversion structure at RM 23.6 allows diversions of water from the White River into a flume and canal system which carry the flow to Lake Tapps. However, the diversion does not have a flood control objective and it is generally not operated during high flow events. For purposes of the current flood study, we assumed that no water was being diverted from the White River to Lake Tapps. 2.3 Principal Flood Problems Climatic and topographic conditions of the upper Snoqualmie Valley create two distinct high-flow periods each year. In the spring or early summer, the seasonal rise in temperature melts snow in the headwaters and causes increased flow. The other high-flow period, the winter flood, is the most damaging. Winter storms bring in moisture-laden air from the Pacific Ocean and mild temperatures causing snowmelt combine to cause floods of high magnitude and short duration. Most of the major floods have occurred during November, December, January, and February. Without the protection by flood-control reservoirs, the communities along the free flowing Snoqualmie River and its forks are vulnerable to severe flooding such as occurred in November 1959 and December 1975. The 42 largest known flood in the Snoqualmie-North Bend area occurred on November 23, 1959. As the rivers in the basin swelled on that November day, there occurred a classic example of how wildly a river can change its course. About nine miles east of the City of North Bend, the South Fork cut a new channel on the opposite side of its valley through what was a section of the main cross State arterial, the Snoqualmie Pass Highway. Atop its newly cut southerly bank, described as a steep clay cliff, the former river bed remained. The torrent on the South Fork left countless homes damaged in North Bend and contiguous areas. The violent turbulence of the Middle Fork washed out principal bridges and left other spans badly damaged. This misfortune left over 50 families stranded for more than a week. Some residents on necessary business, some school children, and carriers of mail and milk treaded lightly by foot across the listing bridges that continued to slip on their supports after the flood. In the City of Snoqualmie, muddy water swept through many homes leaving a trail of destruction. A portion of a city street sank, developing a large cavity as water collected without a natural outlet. Truckloads of concrete slabs and 58 loads of gravel were dumped into the cavity during the flood to save the road, and to prevent adjacent buildings from being swept away. For the entire night of the flood there was no electrical power in the City of Snoqualmie. This flood had a discharge at the USGS gage near the City of Snoqualmie of 61,000 cubic feet per second (cfs). This discharge is equivalent to a 25-year flood at this point (Reference 21). The largest known flood in the Carnation area occurred in December 1975. Agriculture and transportation damages constituted the principal losses. However, the lower valley is inundated to some extent almost every winter. Other major floods occurred in February 1932, December 1967, and January 1969. Storms which cause flooding in the Tolt River Watershed are usually associated with long, steady rains (i.e., winter maritime occluded frontal systems) which are typified by longer duration, more uniform intensity, and more evenly distributed precipitation than the unstable shower (convective) storms. With this type of rainstorm, the flooding in one basin, such as the Tolt, will be associated with flooding on adjacent basins; thus, the rare occurrence of a 1-percent-annual-chance frequency flood on the Tolt would most likely be associated with high water backwater of the Snoqualmie River. The elevation of future floods depends upon the level of the Snoqualmie River at the peak discharge of the Tolt River, the amount of landfill or 43 diking, the physical arrangement or layout, and the hydraulic conditions of the channel. High water marks were provided by landowners and field estimates of survey crews. There are no precipitation gages with long records in the watershed, but the Seattle Water Department has eight storage gages established in 1962-67. The average annual precipitation at these locations ranges from 90 inches (228.6 cm) to 157 inches (398.8 cm). The largest historical flood since 1953 on the Tolt River near Carnation occurred in 1959 with a peak discharge of 17,400 cfs. The Raging River is characterized by a relatively steep gradient resulting in high-velocity flood flows and significant bank erosion and channel aggradation problems. These characteristics have lead to increased flood levels, based on local resident accounts, most likely caused by reduction in channel floodflow conveyance capacity with aggradation. In past floods, large boulders, logs, and debris have been swiftly transported down the river and have partially blocked bridges and threatened the levee systems in the Fall City area. The peak recorded published flow at the USGS gage near Fall City during 40 years of gage operation through 1985 is 3,960 cfs. This occurred on January 24, 1984, and was approximately a 35-year event. Although final estimates of peak flows for an event on November 24, 1986, are not available, provisional estimates between 4,400 and 5,300 cfs have been made by the USGS (Reference 22). Based on the existing frequency curve previous to that event, those flows would correspond with greater than a 2- percent-annual-chance event. Flows in excess of 3,000 cfs were also recorded on February 9, 1951, December 3, 1975, and December 15, 1979 (recurrence intervals ranging from 20 to 30 years). Flooding damage to crops and property in the lower Green River Valley has been a problem since the earliest settlement of the area. Flooding occurred almost annually but the impact to farmland was minimal. After urbanization, the impact of flooding became more severe. Rapid increase in construction of roads, housing, and parking lots increased the volume and rate at which runoff reached the valley floor. Commercial and industrial landfills have been typically located in the lower valley, resulting in alteration of natural drainage patterns and reduction in overbank storage. During periods of excessive precipitation, surface and subsurface runoff from the steep valley walls cause groundwater elevations in the valley floor to rise significantly. This creates open ponding in topographically depressed areas. This condition is further aggravated by floodflows and 44 corresponding high water elevations on the Green River, resulting in a perched channel condition, which prevents natural drainage of subsurface water. In some areas, the overlying soils are generally less pervious than the deeper sands and runoff collects in pond perched above the water table. The land in the lower Green River Valley from Auburn to Renton had historically been inundated by large floods, such as occurred in December 1933, November 1959, and February 1951, until the construction of the Howard A. Hanson Dam. Since operation commenced in 1962, the dam, in combination with levee systems constructed along river segments below Auburn, has prevented that degree of flooding and limited flood damages. During the floods of January 1965, December 1975, and December 1977, discharges downstream were effectively reduced to non-damaging levels. The 1977 flood would have had the highest unregulated peak of any event since diversion of the White River in 1906 (Reference 23). The USACE is responsible for regulation of dam outflows to a rate that will limit flows at Auburn, together with local inflows below the dam, to 12,000 cfs for up to a standard project flood frequency. This flow rate represents a 2-year recurrence interval flood event on the unregulated discharge frequency curve (Reference 24). Under regulated conditions, significant flooding still does occur in areas unprotected by levee systems and from interior local drainage runoff to the Green River. High water levels in the Green River and concerns with existing levee system freeboard and structural integrity limit the discharge of runoff waters carried by Mill Creek (Auburn), the Black River, and various other tributaries. The high water levels of the Green River require that the tributary flows be stored and released by gravity or pump discharge to the river channel in a manner consistent with the requirements of the Green River Management Agreement (Reference 25). Under existing conditions, extensive backwater flooding occurs at the uncontrolled outlets of Mill Creek (Auburn) and Mullen Slough, south and west of State Routes 516 and 167, respectively. The P1 pumping station pumps the flow from the Black River into the Green River. The firm capacity of the pumping station is significantly less than the peak inflows from Springbrook Creek estimated to reach it. No major backwater effects and associated flooding of overbank areas has occurred (Reference 26) since the pump station construction in 1972 and later P1 storage pond excavation. However, analysis shows that backwater flooding will occur upstream of the pump station under existing inflow runoff assumptions and hydraulic structure conditions. Peak outflows from the pump station have not exceeded 525 cfs (November 1986 event) with nominal P1 pond storage (Reference 26). 45 Flooding from Mill Creek (Kent) drainage, downstream of the Earthworks Park regional stormwater detention basin, results primarily from limited capacity hydraulic structures and low stream gradients, extending downstream to its discharge to Springbrook Creek. Downstream of James Street, east bank overflow will occur at peak flood stages of Mill Creek and flow to the headwaters of Springbrook Creek. Although no stream gage records exist for Mill Creek, outflow from the Earthworks Park detention basin for the January 1986 storm event was estimated to be approximately 90 cfs, computed from surveyed high water mark data and hydraulic rating of the outlet. Flooding in the Mill Creek (Auburn) drainage is caused by backwater effects from the Green River, and by overburdened channel capacities and restrictive hydraulic capacities at various roadway culvert crossings. During times of high flood stages on the Green River, which can extend from a few days up to a 1-week period for an extreme storm event, storage of Mill Creek floodwater along the valley floor behind the leveed Green River occurs. A portion of the flow, which would normally enter the Green River via Mill Creek, overflows into Mullen Slough for release back to the Green River, as it recedes, at a lower (downstream) hydraulic gradient. No continuous stream gage records exist within the Mill Creek basin. Crest stage gage records between 1950 and 1970 on the Peasley Canyon tributary drainage indicate a peak recorded discharge of 112 cfs in February 1951 (Reference 27). Mill Creek peak runoff for the January and November 1986 runoff events was not considered extreme based on local accounts and field reconnaissance of extent of flooding. Flooding along Big Soos Creek is primarily limited to the lower gradient channel reaches to the mid to upper portion of the basin, extending upstream from Kent-Black Diamond Road. Wide marshlands are typical in those reaches with narrow channels with limited hydraulic capacities. Existing restrictive bridges and other channel constructions result in increased flood levels and corresponding flooding of the low-lying overbanks. Development does not currently encroach significantly on the floodplain. The maximum recorded floodflow for Big Soos Creek for the 25-year period of record at the USGS stream gage station located above the fish hatchery near the Green River is 1,090 cfs. That event occurred on February 28, 1972, and has an approximate recurrence interval based on period of record frequency curve computation of less than 10 years. Floodflows of greater than 1,000 cfs also occurred in November 1960, 46 January 1964, and February 1982. Preliminary estimates of peak flows for the January and November 1986 storm events do not exceed 900 cfs. On the White River, the flood of 1975 overtopped and subsequently eroded a section of the levee on the left (south) overbank, upstream of the study area at approximately RM 10.6. It is unlikely that the levee will be repaired within the foreseeable future. Consequently, high flows on the White River are expected to cause flooding in the left overbank, outside the levee, for a distance of approximately 2.6 miles before floodwaters are returned to the main channel at approximately RM 8.0. Approximately 0.8 mile of this overbank flooding occurs within the Auburn corporate limits, inundating areas which are presently wooded and unclassified, but which are earmarked for future single-family residential development. The amount of storage provided naturally by Lake Sammamish has a moderating influence on flow, and the channelization project by the USACE has significantly reduced flood problems on the Sammamish River. The primary areas that are subject to flooding are adjacent to tributary inlets where the channel berm is interrupted. On Lake Sammamish, the highest flood during a 37-year period of record occurred on February 11, 1951, when the water-surface of the lake reached an elevation of 33.44 feet National Geodetic Vertical Datum (NGVD). Calculations by the USACE indicate that the 1951 inflow would have raised the lake elevation to 29 feet NGVD had the present improved outlet been in operation (Reference 28). On December 5, 1975, the lake level reached 29.70 feet NGVD. Generally, the lake level ranges between 25 feet NGVD in summer and 28 feet NGVD in winter. The largest recorded floodflows on Swamp Creek occurred on January 18, 1986, when a flow of 1,090 cfs (provisional) was measured at the USGS gaging station at Kenmore. This flow exceeds the 1-percent-annual- chance event magnitude based on the 23 years of gage record through 1986. The previous measured peak flow on Swamp Creek occurred on March 6, 1972, with a value of approximately 490 cfs. Numerous private bridges along the lower reaches of Swamp Creek and encroachment on the creek channel from development provides restrictions to flow that may result in increased flood levels and additional overflows to typically low-lying overbank areas. Although localized flooding damages were reported for the January 1986 extreme runoff event, they were primarily related to channel bank erosion, overtopping of roadways and resulting damages (including culvert washouts), and limited damages to residential structures. 47 The natural channel of North Creek lies on the opposite side of the valley from where the stream now flows. The creek was relocated to the high side of the valley to improve its capacity. The last reported flooding on North Creek occurred in March 1950, when the flow reached 680 cfs. This event was slightly greater than then 1-percent-annual-chance recurrence interval. Because land use in the valley is agricultural, the flooding had minimal impact. Highwater in December 1975 was reportedly contained within the North Creek channel. There are no gage records of this event. Localized ponding areas develop every winter because of the poorly drained soils in the valley. Frequent flooding occurs on Little Bear Creek in the Woodinville area near the confluence of the Sammamish River. The hydraulic structures and channel capacities are limited along the stream reach between the culverts under NE 178th Street and State Route 202. This causes frequent overflows, primarily along the south bank, which are removed from the stream system and flow independently to the Sammamish River. South overbank flows, downstream of the State Route 202 culvert, combine with overflow immediately upstream of the same culvert and flood the low- lying Burlington Northern Railroad underpass area with ponding depths exceeding six feet. This overflow and ponding, with outflow across NE 175th Street south to the Sammamish River, frequently floods local commercial structures. Limited overflows along the north creek bank, upstream of NE 178th Street, cause shallow flooding to commercial structures and surrounding roadways, as was experienced in the January 1986 event. Flooding damages upstream of State Route 202 are not typically severe, primarily because of the undeveloped character of areas near the stream course and floodplain. No operational stream gages exist on Little Bear Creek to directly estimate flooding magnitudes; however, analyses of hydraulic ratings for the channel, culvert, and overflow components provided an approximate peak flow estimate of 650 cfs for the January 1986 event. Review of local precipitation records and comparison with, and transfer of, flow records from adjacent gaged basins indicates that the event most likely represented a recurrence interval of greater than 1-percent-annual-chance magnitude. A private commercial business crossing between the State Route 202 crossing and NE 178th Street was washed out during that flood event. The flood season for Bear and Evans Creeks is from October to March. The greatest floods are caused by rainstorms although melting snow may occasionally augment flooding. Storm runoff in the Bear Creek basin is comparatively slow because of the moderate terrain, the unimproved condition of the channels, and the small amount of residential and commercial developments in the watershed. As a rule, the stream rises to a peak stage within a day and the duration of flooding is less than a week. 48 The largest recorded floodflow on Bear Creek within the limited period of gage record was a recent event on January 18, 1986, with estimated provisional peak flows of 390 cfs at the USGS gage near Redmond (upstream of Cottage Lake Creek) and 1,550 cfs at the USGS gage at Redmond, upstream of the Sammamish River confluence. Based on updated frequency curves including that event, the estimated recurrence interval of floodflows within the Bear Creek basin for that event is approximately 40 to 50 years. The previous recorded peak flows at those gages were 250 cfs and 456 cfs, respectively, although the gage record is limited to eight years for each station. There are numerous bridges over Bear Creek within the study area, many of them private crossing with restrictions that limit capacities and increase upstream flood levels. During major floods, debris collecting at these structures may significantly increase the extent of flooding and potential for overflow with resulting damages to roadways and adjacent structures. Damage reports from the January 1986 event were not extensive; however, roadways were overtopped at a few crossings and a mobile home park was flooded and had to be evacuated along the lower reaches of Bear Creek. The flood season for Issaquah and Tibbetts Creeks is during the winter from October to March. The greatest floods are caused by rainstorms although melting snow occasionally augments flooding. The creeks rise quickly during heavy rainfall because of the steep terrain in the watersheds. As a rule, the streams rise to crest stage within a day and the duration of flooding is less than a week. The largest recorded peak floodflow on Issaquah Creek in the years of USGS gage record since 1964 occurred on November 24, 1986, when a peak discharge of 3,050 cfs (provisional) was recorded at the USGS gage ―near mouth, near Issaquah‖ (Reference 22). That floodflow represents an approximate 25-year recurrence interval based on frequency curves for gage record prior to that event. The flooding event of January 18, 1986, produced the third highest period of record gage flow on Issaquah Creek, estimated at 2,400 cfs (provisional) by the USGS (Reference 29), with an estimated recurrence interval of less than 10 years. Peak runoff for a January 1, 1964, event of 2,870 cfs represents the second highest flow on gage record. There are numerous bridges spanning Issaquah Creek. The clearance and flow capacity of many of these bridges are restricted. During major floods, debris collecting at these structures may significantly increase the extent of flooding. Development along Issaquah Creek has encroached on the channel, particularly in the downstream reaches in and surrounding the 49 City of Issaquah. This encroachment reduces the flood-carrying capacity of the channel, increasing the flood depths in adjacent areas. Local accounts and aerial photographs (Reference 29) of flooding in the City of Issaquah and along the West Fork Tributary indicated that flood levels for the November 1986 event were the highest in recent years. Numerous roads and structures were inundated. Peak floodflows from the West Fork of Issaquah Creek are relatively small compared to those of the mainstem; however, significant areas of flooding occur in the upper reaches of that tributary. The flooding is a result of an extremely low gradient stream channel, having a small channel capacity with wide and flat overbanks. Flood damage on May Creek occurs mainly at the mouth where a lumber mill was built on the small delta there. Upstream of I-405, May Creek flows generally within a canyon. Flooding problems in this reach are the result of surface runoff and ground-water seepage from the steep canyon walls rather than excessive overflow of May Creek. For the reach of May Creek under study upstream of the Coal Creek Parkway, flooding results from channel and bridge capacities restrictions and flattening of stream gradients in the upper May Valley area. For the reach extending upstream to 146th Avenue SE, flooding is typically confined to a relatively narrow, steep channel. Upstream from that crossing, the floodplain expands to the overbanks where floodplain inundation widths between 500 and 1,000 feet are typical for significant storm events. Filling of floodplain overbanks and reduction in storage, and debris buildup at the hydraulic structures, can increase flood levels and the extent of upstream overbank flooding. Flooding extent on the May Creek Tributary, upstream of SE May Valley Road, results primarily from backwater effects of the main channel at their confluence. A USGS stream gage exists on May Creek (discontinued) at its mouth near Renton. The peak flow recorded at that station during the 15 years of gage operation was 510 cfs on December 3, 1975. This corresponds to a storm with a recurrence interval of approximately10 to 15 years based on the period of record frequency curve. High water marks located immediately upstream and downstream of the gage were observed for the January 1986 storm event. Results of approximate rating analyses at the gage for that event indicated floodflows potentially exceeding 800 cfs with an expected recurrence interval of greater than the 2-percent-annual- chance flood. Flooding, including inundation of structures in the upper May Valley area, was reported for that event. Flooding along Vasa Creek generally occurs during the winter months, November through February, when storms originating over the Pacific Ocean bring intense precipitation. These storms usually last two or three days, and streams may increase from low flow to flood discharge within 6 50 to 12 hours. The major flood problems are those of inundation and damage of private property from out-of-bank floodwaters, primarily along low gradient reaches of the streams. The Cedar River is subject to frequent flooding damages, particularly in its upper reaches, beginning with minor flooding and bank erosion when the river flow, measured at Landsburg, exceeds 2,500 cfs. This magnitude of flows typically occurs annually. Major flooding occurs when river flows reach 4,000 cfs, which happens on the average once every five to 10. years. Topographic and climatic conditions of the basin produce two high-water periods during the year. The highest flows normally result from extreme rainfall and the accompanying snowmelt that can occur during the late fall and early winter. Flooding can also occur during spring months, resulting primarily from snowmelt events. Stream flow on the Cedar River has been recorded almost continuously since 1895 at the gage near Landsburg. The greatest flood which has occurred over the past 50 years took place on December 4, 1975, with a peak discharge at Landsburg of 8,800 cfs. Based on an updated frequency curve for the Renton USGS stream gage for the 40 years of record through 1985, the recurrence interval for that event exceeded 1-percent-annual- chance. Preliminary peak flow estimates by the USGS (Reference 22) for the recent November 1986 event indicate a peak flow of approximately 5,300 cfs, with a recurrence interval of approximately 100 years. Preliminary peak flow estimates by the USGS (Reference 22) for the recent November 1986 event indicate a peak flow of approximately 5,300 cfs, with a recurrence interval of approximately 10 years. Damages in the Cedar River basin from the December 1975 flood event were estimated at $1,760,000. In the reach under study, the west bank of an improved channel at the mouth of the Cedar River was overtopped above the South Boeing Bridge and the Renton Municipal Airport experienced significant flooding and had to close down until the floodwaters receded. Extent of flooding for the November 1986 event in the lower 2-mile reach under study was mainly limited to the improved channel with the exception of some overbank flooding adjacent to the Renton Airfield. Upstream of the improved channel, portions of the Maplewood Additions and other scattered residential developments have been inundated by past flooding events. Log and debris jams have been experienced on the lower river channel, especially during the 1933 and 1975 floods. The lower reach of the river channel, through the City of Renton, has been aggrading in recent years based on comparison of current and previous cross-section data. This may result in increases in flood levels and potential overflows. 51 A reach of the Cedar River about 0.8 miles in length along the right bank immediately upstream of I-405 is seriously obstructed. Various private enterprises along this river reach have encroached on the stream bed by dumping waste concrete and asphaltic concrete. Fill has been placed, paved, and riprapped to accommodate parking facilities for tenants residing at the Riveria Motel. This fill encroaches into the river 25 to 40 feet along the entire width of the property. Encroachment of this type reduces the river channel capacity, creating higher water levels adjacent to and upstream of these areas. Flooding along Mercer Creek, Richards Creek and its tributaries, Kelsey Creek and its tributaries, and North Branch Mercer Creek generally occurs during the winter months, November through February, when storms originating over the Pacific Ocean bring intense precipitation. These storms usually last two to three days and streams may increase for low flow to flood discharge within 6 to 12 hours. The major flood problems are those of inundation and damage of private property from out-of-bank floodwater, primarily along low-gradient reaches of the storms. Ice jams have little impact on flooding when culverts and bridges are free of debris. Flood elevations, however, are increased because of the limited capacity of some culverts. In some cases, this limited capacity is intended as a means of peak-flow retention. Numerous bridges and culvert systems exist along Thornton Creek from its outlet to Lake Washington at Matthews Park to its forks, and extending upstream to and above I-405. Flooding for moderate runoff events is primarily contained by the Thornton Creek drainage system. However, the restrictions imposed by the crossings and encroachment on the channel in this heavily urbanized basin result in backwater flooding and overflow of channel banks and structures, with resulting damages, under more severe runoff conditions. Debris collection, particularly as it affects outflow to the diversion works, has had significant impacts on increasing inundation levels during past flooding events. Since the November 1978 storm event that resulted in flooding problems augmented by debris, the City of Seattle has improved the operation and maintenance of the diversion works structure, located at RM 1.3 on Thornton Creek, below the confluence of the North and South Forks. This diversion works structure diverts flows up to an estimated 340 cfs for the 1-percent-annual- chance event into an abandoned 72-inch concrete sewer pipe. This pipe discharges directly into Lake Washington just north of Matthews Beach. The diversion structure functioned adequately during the January 1986 storm event. Based on hydraulic rating analyses performed from surveyed high water marks, peak runoff for that event was estimated at 560 cfs 52 above the diversion and downstream of the creek forks and 220 cfs in the main channel downstream of the diversion works. Some minor flooding has occurred in the past in the lower reaches of McAleer Creek. This flooding was caused by hydraulic structures of inadequate capacity or sedimentation and debris accumulation. Particular dates of past flooding are not available. Flooding along Coal Creek generally occurs during the winter months, November through February, when storms originating over the Pacific Ocean bring intense precipitation. These storms usually last two to three days, and streams may increase from low flow to flood discharge within 6 to 12 hours. The major flood problems are those of inundation and damage of private property from out-of-bank floodwaters, primarily along low gradient reaches of the streams. The flood season for Forbes Creek in the lower Puget Sound region is normally during the winter from October to March. The larger floods are caused by rainfall, although melting snow occasionally augments flooding. Forbes Creek has no gaging station and there is no written record of historical flooding. Discussions with residents revealed a history of localized flooding of short durations caused by brief periods of intense rainfall. Debris collecting at structures and residents encroaching on the channel capacity by placing various types of materials to stabilize the streambank, may significantly increase the extent of flood. Flooding along Lyon Creek has occurred in the lower reaches and also in the southwest corner of NE 185th Street and 35th Avenue NE nearly every winter. Hydraulic capacity has been greatly reduced in the two concrete box culverts under Bothell Way Northeast. Sedimentation in the southern portion, up to approximately 2 feet from the original invert, has diverted all the flow through the northern portion. At higher flows this would create unnecessary backwater in the upstream channel in front of the shopping center complex or the sediment could become dislodged causing a blockage elsewhere downstream. Flooding along Yarrow Creek, Meydenbauer Creek, and North Fork Meydenbauer Creek generally occurs during the winter months, November through February, when storms originating over the Pacific Ocean bring intense precipitation. These storms usually last two to three days, and streams may increase from low flow to flood discharge within 6 to 12 hours. The major flood problems are those of inundation and 53 damage of private property from out-of-bank floodwaters, primarily along low-gradient reaches of the stream. The major source of flooding within Skykomish is the South Fork Skykomish River. Flooding occurs primarily during the winter due to rainstorms which bring intense precipitation and are accompanied by warm winds that rapidly melt the accumulated snowpack. During such storms, river discharges may increase from a relatively low base flow to near flood stage within a few hours. Residents report that the largest flood on record occurred in November 1959. The return period for that flood is approximately 30 years. Although a dike contained most of this flow in the eastern part of the town, water covered the central and western areas. A flood also occurred in 1975, and floodwaters reached the tops of the levees. The return period for that flood is less than three years. The other potential source of flooding within Skykomish is Maloney Creek, which meets the South Fork Skykomish River near the western corporate limits. This stream flooded in 1933 when a logjam that had been holding back the flow broke. No information on the recurrence interval for this flood is available. There has been no flooding reported on Maloney Creek since that time. The flooding problems in the lower portions of Miller and Walker Creeks are a result of increasing development, which has caused more rapid runoff in those creeks. This development is primarily outside the City of Normandy Park boundary and has been the subject of much discussion and some litigation. Damage has generally been limited to stream erosion and some limited flooding around residences. The area most subject to flooding along the lower portions of Des Moines Creek is owned by the Covenant Beach Bible Camp. The streamflow of Des Moines Creek exceeds the channel capacity several times each year, resulting in several thousands of dollars of damage each year. Damage is usually limited to bank erosion, overbank deposition, and some shallow flooding in and around occasionally occupied camp cottages. The last major flood event along Miller and Des Moines Creek was in February 1972, and had a recurrence interval estimated at 10 years. As a result of Miller Creek flooding, a suit was brought against the county to restrict the diameter of the 8.5-foot culvert on First Avenue South through which Miller Creek passes. A 6-foot diameter collar was placed in the upper end of the culvert. The effects of the collar have been included in 54 the hydraulic analysis of Miller Creek. As a result of Des Moines Creek flooding, a 4-foot-deep hole was eroded around one of the cottages and water up to approximately 2 feet deep was standing in others. The December 15, 1977, high tide provided a high tide in Puget Sound of an approximate recurrence interval of 70 years. This high tide was accompanied by very little wind. Flooding occurs at numerous locations along Longfellow Creek because of restricted channel and culvert capacities and partial obstruction of the natural channel because of debris accumulation. Overtopping of the majority of the roadway crossing between SW Brandon Street and SW Myrtle Street, including localized flooding of properties, structures, and bank erosion, occurred during the January 1986 flooding event. Downstream of the study limit, flows at SWE Nevada Street overtopped an approximate 30-foot-high roadway fill, partly because of culvert debris blockage, and resulted in failure of that crossing with extreme floodflows released to the downstream drainage. Surface flooding also occurs at locations where the lateral storm drainage systems have insufficient capacity to convey storm runoff into Longfellow Creek. The existing culverts that convey Rolling Hills Creek under I-405 at its intersection with State Route 167, and through a closed culvert behind the Renton Cinema, cause overbank flooding north of the channel in the parking areas for the Cinema and the Renton Village Development. Significant reduction in peak flows through the downstream highway culvert is achieved from routing of floodwater that pond in the overbank. 2.3.1 Revision 1 – Miller Creek On January 8, 1990, a flood on the order of the 1-percent-annual- chance event inundated farm lands, pasture lands, and residential yards neighboring the creek. Farm and pasture lands sustained no significant damage, but several homes did. A homeowner located at the northwest corner of South 160th and 9th Avenue South reported 4 feet of water in her basement. The yard of the home located on the southwest corner of this intersection was severely eroded by high-velocity water issuing from the culvert that conveys Miller Creek flow under 160th Avenue. Near 8th Avenue South, the stream jumped its west bank and damaged the contents of a garage/workshop. Several homes between 8th Avenue South and Des Moines Way were also flooded. Downstream from 1st Avenue, the creek is confined to a deep ravine, which does not pose a threat to neighboring property. As it leaves the ravine, the creek flows along the west side of the Southwest Suburban Sewer District sewage treatment plant. 55 During the January 1990 flood, the creek remained within its banks through this reach. Below the treatment plant, the stream profile begins to flatten and the floodplain widens. Two homes at the intersection of Miller Creek and SW 175th Place were flooded. Below SWE 175th Place, the floodplain widens and has been preserved as a community park for residents of the City of Normandy Park. Much of it was also covered by water during the flood. 2.3.2 Revision 2 Snoqualmie River No additional information is available. 2.3.3 Revision 3 Raging River The Raging River experienced a flood of 6,220 cfs (nearly the 100- year event flow) in November 1990, and 5,330 cfs in November 1986. Both events significantly impacted Preston-Fall City road and numerous properties and structures. 2.3.4 Revision 4 – North Fork Issaquah Creek Information on the frequency and extent of past flooding along North Fork Issaquah Creek is very limited, and no information is available for most of the study reach. Areas where past flooding has occurred were identified through interviews with local residents during field surveys made by nhc in October and November 1994, and during a 2-year flood event in February 1995. At Issaquah Creek near the mouth, a 56.6-square-mile basin area, major floods with nearly identical peak flows, 3,100 and 3,200 cfs, were recorded on November 24, 1986, and January 9, 1990, respectively. These floods each had a return period of approximately 30 years. Major floods are believed to also have occurred on North Fork Issaquah Creek on the same dates. Coincident flooding is confirmed by a King County stream gage on the North Fork Issaquah Creek channel to have occurred on January 9, 1990; that gage had not yet been installed at the time of the 1986 flood. No information on past flooding was available for the 0.7-mile reach between the 60th Street SE bridge and the I-90 interchange. Flooding of the area immediately upstream of the I-90 interchange 56 occurred on several occasions after construction of this interchange in approximately 1968. Additional information on past high-water levels is available from a stream gage operated by the King County Division of Surface Water Management (KCSWM) at the 66th Street SE bridge crossing of North Fork Issaquah Creek. The maximum water elevation recorded during the January 9, 1990, flood was 72.8 feet, which is approximately 0.6 foot below the low cord of the bridge. 2.3.5 Revision 5 North Creek No additional information to add. 2.3.6 Revision 6 Tolt River Recent major floods on the Tolt River occurred in November 1990, November 1995, and February 1996. Each had a peak magnitude that was smaller than the current 10-year flood. The three largest Tolt floods on record occurred in 1950s before dam operation began, and all three were close to the current 20-year flood. The Tolt River levees were damaged at three locations in the winter of 1995/1996, and were subsequently repaired. The 1990 flood caused extensive damage to the north bank levee downstream of State Route 203, primarily along the top of the levee. Upper South Fork Snoqualmie River Significant flow events occurred during the month of November in 1986 and 1990, affecting some residential areas along this fast flowing river and causing surface erosion damages to several flood protection facilities (i.e., revetments and levees). The levees are located in the lower portion of the reach with revetments extending farther upstream 2.3.7 Revision 7 Recent large floods at the Carnation gage include November 1990, which had a discharge of 65,200 cubic feet per second and a flood elevation of 60.70 feet. Two people were killed by flooding in the lower Snoqualmie River basin in the 1990s. Both failed in attempts to drive across the 57 mile-wide valley bottom on flooded roadways. The November 1990 flood killed hundreds of dairy cows and other livestock in the lower Snoqualmie basin. Subsequent floods have not had similar animal mortality, in part because the dairy industry no longer dominates valley land use. Homes and other structures throughout the lower Snoqualmie basin are subject to flood damage. For the most part, these structures were developed for agricultural use and have been placed on the highest portions of large floodplain parcels. Nonetheless, deep and fast flows are a hazard throughout the lower Snoqualmie River floodplain. 2.3.8 Revision 8 Cedar River – Within the Area of City of Renton - Significant flooding problems have occurred along the downstream end of the study reach at the Renton Airport and on Boeing company property. Flooding has also been a problem within the Maplewood subdivision upstream near the Highway 169 Bridge. Periodic surveys of the river channel indicate that the bed of the river in the channelized downtown reach near the airport aggrades fairly rapidly. Significant debris accumulations have also occurred in this reach during large floods. Both factors contributed to substantial flooding at the airport and Boeing during major floods in December 1975 and November 1990, and during a smaller flood in November 1995. Portions of the Maplewood area experienced flooding during these events as well. The recurring flooding problems at the airport and on Boeing property prompted the development of a USACE Section 205 comprehensive flood-control plan for the lower Cedar River to prevent flooding up to the 1-percent-annual-chance flood. The project included the construction of levees and floodwalls, dredging of the riverbed and modifications to the south Boeing Bridge. USACE constructed the project in 1999 and 2000, which includes a series of levees and floodwalls along both sides of the river downstream of Logan Avenue and a levee on the left bank just upstream of Logan Avenue. The USACE also dredged the riverbed from Lake Washington upstream to approximately Logan Avenue. In addition, the south Boeing Bridge was modified and fitted with hydraulic jacks to lift it above the water during flood events. The levees and floodwalls are USACE certified and designed to provide protection for the 1-percent-annual-chance flood with greater than 90 percent reliability, assuming the channel is periodically dredged as outlined in the Cedar River at Renton 58 Flood Damage Reduction Project Operation and Maintenance Manual (Reference 144). Green River - Because of the flow regulation provided at Howard A. Hanson Dam, the Green River does not generally cause significant flooding in the study area. An exception to this is the area at the confluence of Mill Creek/Mullen Slough with the Green River. This area generally floods whenever flows in the Green River at Auburn exceed about 10,000 cfs. As flows approach 12,000 cfs, the flooding in this area may close roads, inundate houses and businesses, and cause other problems. This flooding can have significant impacts, as many people use these roads to access their homes or workplaces. While flooding in the Lower Green River and Middle Green River is likely significantly less pronounced than in the period prior to the construction of Howard A. Hanson Dam (1961), the potential impacts of flooding are now much greater due to the nearly complete development of the floodplain. Factors contributing to flooding along the Lower Green River include channel changes (both natural and man-made) such as aggradations, levees, and revetments. There is significant overbank inundation along the entire study reach of the Middle Green River during large floods. This flooding, although natural for a low gradient stream, has significant impact to residents along the river, many of whom need to use the roads in the floodplain to access their homes. Flood levels in the lower end of the Middle Green River study reach may also be affected by backwater effects from a large natural log jam near RM 32.3. Kelsey Creek - Anecdotal information provided by City of Bellevue staff indicates that significant overbank flooding along the Kelsey Creek study reach is minimal, with the exception of flooding near the Illahee Apartments on Bel-Red Road and in the lower reaches near the Glendale Golf Course and within Kelsey Creek Park. Frequent flooding has also been observed on the West Tributary within the golf course and park. Patterson Creek - There is significant overbank flooding along the mainstem of Patterson Creek during large storms. This flooding, although natural for a low gradient stream, has significant impact to residents along the stream, many of whom cross the floodplain to access their homes. Contributing factors to mainstem flooding include: beaver dams, reed canary grass choking reducing channel capacity and limiting the ability of the channel to cut new channels around barriers such as beaver dams, 59 and backwater effects from the Snoqualmie River. Flood levels in the lower two miles of Patterson Creek may be exceeded by up to 10 feet or more by flood levels on the Snoqualmie River. Lower Snoqualmie River - The Snoqualmie Valley is a wide, low gradient floodplain mostly comprised of agricultural lands with a few relatively small residential communities. Flooding is most commonly associated with inundation of farm houses and barns, and the valley roads that parallel or cross the mainstem Snoqualmie River. Damage is often due to large areas of inundation along with localized erosion of outer river banks and revetments, overtopping of flood protection levees, and road embankments. Although the mainstem Snoqualmie is characterized by relatively low velocities and a mild gradient, flooding can cause substantial localized erosion. Problems generally relate to constrictions, where flow energies become concentrated. The Carnation Farm Road is such an example; the road fill embankment forces flood waters through two small bridge openings. Both bridge approaches were washed out during the Thanksgiving 1990 flood event when flood flows exceeded their capacity. Existing King County flood control facilities (levees and revetments) in this basin sustained damages of just over one million dollars in the Thanksgiving 1990 flood. In addition to this erosion damage, the deep, broad flooding of the Snoqualmie River valley brings other damages. The Thanksgiving 1990 flood killed hundreds of cows on the lower valley's dairy farms. Rising flood waters damaged homes near Carnation and scattered locations elsewhere throughout the valley. In two separate incidents (January 1990 and November 1990), motorists drowned when they attempted to drive across flooded valley roads. Springbrook Creek – No additional information provided. 2.3.9 Revision 9 Puget Sound No additional information to add. Sammamish River - There are no known recent reports, from the County or from local communities, of the Sammamish River flooding into its overbanks. In January 1997, a flow of approximately 2,900 cfs occurred. This is the largest recorded 60 flow at the Northeast 116th Street stream gage since monitoring began in water year 1966. Observed flooding in the overbanks for this event was attributed mostly to tributary flow and local runoff and not direct flooding from the Sammamish River. However, overbank flooding may occur for events approaching the 1- percent-annual-chance exceedance event, especially if water were to escape the berms along the edge of the main channel. Overbank flooding in the middle river segment, where land use is dominated by agriculture, has minimal impact on health and safety, but in more heavily developed areas it can have significant impacts on residents and commercial and industrial properties along the river. Potential impacts of the flooding will continue to increase if development in the floodplain increases. The existence and impact of future flooding problems along the study reach may also be affected by channel changes, constrictions at bridges, and other development in the floodplain. White River – During large floods there is the potential for significant overbank inundation throughout White River. This flooding, although naturally occurring, can have significant impacts on residents along the river. While flooding along the White River is likely less frequent and less severe than in the period prior to the completion of Mud Mountain Dam in 1948 (Reference 186), the potential impacts of flooding continue to increase as development in the floodplain increases. Flood problems may also be exacerbated by channel changes, constrictions at bridges, and other infrastructure in the floodplain. 2.4 Flood Protection Measures The Seattle office of the National Weather Service maintains and collects hydrometeorological reports from a network of substations and uses this information to prepare flood forecasts for King County streams. Flood warnings are issued by them and given wide dissemination through all media by cooperative efforts with local and Federal agencies. Levees exist in the study area that provide the county with some degree of protection against flooding. However, it has been ascertained that some of these levees may not protect the community from rare events such as the 1-percent-annual-chance flood. The criteria used to evaluate protection against the 1-percent-annual-chance flood are 1) adequate design, including freeboard, 2) structural stability, and 3) proper operation and maintenance. Levees that do not protect against the 1-pecent-annual-chance flood are not considered in the hydraulic analysis of the 1-percent-annual-chance floodplain. 61 Levees on the Tolt River, near its confluence with the Snoqualmie River, provide moderate protection to urban development in the City of Carnation and to adjacent agricultural lands. A 600-acre agricultural area on the left bank of the Snoqualmie River, 1 mile downstream from Fall City, is protected from minor spring floods by a levee approximately 1 mile long. Levees along the lower 2 miles of both banks of the Raging River and its confluence with the Snoqualmie River protect a portion of Fall City and agricultural lands. Levees along the South Fork of the Snoqualmie River provide approximately 2-percent-annual-chance flood protection to the City of North Bend. Bank erosion occurs at nearly all river stages, but is most severe during medium and high flows. Bank protection projects have been constructed at numerous locations along the Snoqualmie River and its major tributaries by riparian owners, local governmental agencies, and the Federal government. In 1960, the City of Seattle constructed a water supply project on the South Fork of the Tolt River. Total storage capacity of the reservoir is about 58,000 acre-feet. Although flood control storage is not a project feature, some minor storage of flood discharges does occur. The USACE operates the Howard A. Hanson Dam at Eagle Gorge on the upper Green River. Completed in 1962, the dam provides approximately a 500- to 600-year level of protection against overbank flooding by the Green River. The dam is a rockfill embankment approximately 235 feet high with a gated spillway and a maximum reservoir elevation of 1,222 feet. Stored water is released as soon as possible after a flood to provide for the possibility of a second flood. The USACE current operation of Hanson Dam provides that all runoff is passed through the dam until the flow at the Auburn gage is expected to reach 12,000 cfs. At that point, further releases are regulated to maintain no more than 12,000 cfs at Auburn. Channelization and levee construction, primarily downstream of Auburn, has provided additional flood protection for the overbanks. A total of approximately 16 miles of levees have been constructed in addition to roadway systems that function as levees, between State Route 18 at Auburn and the Black River confluence at Tukwila. Based on information received from the USACE, the levee system along the left (west) bank of the Green River, from Strander Boulevard to RM 16.7, in the City of Tukwila, will adequately provide protection against overtopping or failure caused by the 1-percent-annual-chance flood, with at least 2 feet of freeboard. 62 King County and the various incorporated cities along the Green River (Tukwila, Renton, Kent, and Auburn) are responsible for maintenance of portions of those levee systems. Since the adoption of enabling legislation by the State of Washington in 1945, the State and King County have combined to control riverbank erosion. The Black River basin, including Springbrook Creek, has been the object of the ongoing East Side Green River Watershed Study (Reference 30). That study was initiated in 1965 by the former SCS with the support of King County and the Green River Valley cities. The P1 pumping station and storage pond, as part of the plan, were constructed in 1972 and 1984, respectively. A major box culvert replacement was installed at SW Grady Way in 1986 and is considered in this study in its partially obstructed condition. Preliminary plans exist for the construction of the P1 channel from SW Grady Way north to the storage pond and additional culvert replacements under Interstate 405 and SW 16th Street. The timing and funding for construction of these improvements is not finalized; therefore, they are not considered in this study. A regional detention basin was constructed on Mill Creek (Kent) in 1981 at Earthworks Park in order to provide flood-control storage for reduction in downstream peak runoff. A second smaller upstream detention basin was previously constructed in the Upper Mill Creek basin to provide for additional reduction in peak flows to the lower valley areas. This has reduced the magnitude and frequency of, but not eliminated, flooding problems downstream of the Earthworks Park structure. The City of Kent is developing a plan to construct more detention storage in order to further alleviate their flooding problems. Partial reduction in peak runoff conveyed to Mill Creek (Auburn) is provided by stormwater detention storage basins constructed on the south tributary to Mill Creek, above its confluence with the Peasely Canyon tributary. Locally referred to as the ―Auburn 400‖ ponds, and located east of and adjacent to State Route 167 and 15th Street SW, they provide an unidentified effect on routing of peak tributary flows to Mill Creek. Additional regional detention storage is being considered for other study reaches of Mill Creek, downstream of State Route 18, in an attempt to maintain adequate storage capacities for limiting downstream discharges with continued floodplain development. On the White River, peak flows are regulated by the Mud Mountain Dam, a structure built by the USACE. Storage was initiated in 1942, and the project was finally completed in 1953. The structure is an earth and rockfill dam, 425 feet above bedrock. The reservoir has a storage capacity of 106,000 acre-feet of water and is capable of controlling floods 50 percent greater than the maximum flow of record. 63 Levees have also been constructed along portions of the White River along its course through the Cities of Auburn and Pacific. The amount of storage provided naturally by Lake Sammamish has a moderating influence on flow, and the channelization project of the Sammamish River by the USACE has significantly reduced flood problems. Major drainage improvement and partial flood protection are provided by the channel improvement project completed in 1966 by the USACE for King County. The project extends from below Lake Sammamish to Kenmore, a distance of approximately 14 miles. The river channel was deepened an average of 5 feet and increased in width from a former average of about 15 feet to the improved 32 to 50 feet. Excavated material from the channel enlargement was used to construct the levees. A low weir with a crest elevation of 28.1 feet NAVD 1988 was constructed to control the outlet of Lake Sammamish. The channel improvement and outlet project provide protection against spring floods with a recurrence interval of 10 years without causing Lake Sammamish to rise higher than elevation 32.6 feet NAVD 1988. No significant flood-control measures have been developed on the Sammamish River tributaries except for channelization of the lower end of Bear Creek at Redmond (Reference 28). Most of the channel of May Creek is in its natural condition. The lower 1,000 feet have been channelized to alleviate flooding problems caused by channel aggradation resulting from excessive siltation problems. King County has established a flood fighting plan that is activated when the Cedar River reaches a discharge of about 4,000 cfs at Renton. The plan consists of patrolling and making emergency repairs to contain this discharge. When the flow exceeds 4,000 cfs, efforts are concentrated on protecting the safety of the affected residents and their personal property. The Sheriff’s office, the Office of Civil Defense, fire districts, and the Red Cross are notified for assistance. The lower 1 mile reach of the Cedar River channel was initially stabilized in 1912. King County and the City of Renton have provided major capital improvements and maintenance for flood and erosion control along the Cedar River. This has included riprap bank protection works, bulkheads construction, cleaning, and snag removal. Major reconstruction of levees and bank protection work was accomplished after the December 1975 flood. River channel dredging upstream from the mouth of the Cedar River has been performed, most recently in 1972, in an attempt to maintain 1-percent-annual-chance flood protection of the improved channel system through the City of Renton. 64 The major flood-control improvement to Thornton Creek is the diversion works with a 72-inch overflow pipeline to Lake Washington. The diversion reduced the peak flows to the lower mainstem reach of Thornton Creek such that only minimal downstream flooding hazards exist up to a 1-percent-annual-chance frequency existing conditions flooding event. This assumes that full unobstructed capacity is maintained to the diversion pipeline. In 1946, the USACE constructed a levee along the south bank of South Fork Skykomish River in Skykomish. This levee is approximately 970 feet long and provides variable flood protection to a portion of the town. A flood-protection structure that significantly influences flooding on Des Moines Creek is the road embankment from Marine View Drive located in the City of Des Moines, which creates enough detention storage to reduce the peak 1-percent-annual-chance flood by almost 50 percent on Des Moines Creek. In 1983, the City of Seattle constructed a regional stormwater detention basin on Longfellow Creek south of SW Webster Street. The detention basin has helped reduce downstream flooding problems, although basin overflow for more severe storms, as evidenced in the January 1986 event, will reduce the basin’s effectiveness on reduction in peak flows. There are no other flood-control measures for other streams studied that significantly reduce flooding. 2.4.1 Revision 1 - Miller Creek In October 1992, King County completed the construction of the Lake Reba Regional Stormwater Detention Pond, which will attenuate flood flows in Miller Creek. The facility is located at the site of Lake Reba, just south of State Route 518. The effect of this facility has been accounted for in the hydrologic and hydraulic analyses. There are no other major structural flood-protection measures planned for Miller Creek. 2.4.2 Revision 2 Snoqualmie River No additional information to add. 2.4.3 Revision 3 Raging River No additional information to add. 65 2.4.4 Revision 4 North Fork Issaquah Creek - There are no existing flood- protection measures along North Fork Issaquah Creek. 2.4.5 Revision 5 North Creek (LOMR) - The flood-protection system comprises interconnected levees located along three separate project areas: the downstream reach of the levee system for the Quadrant Business Park project area is located along the east bank of North Creek from I-405 to 195th Street Northeast; the levee system for the Koll Business Center project area is located along the east and west banks of North Creek from 195th Street Northeast to Northeast 205th Street; and the upstream reach of the levee system for the Quadrant Monte Villa Center project area is located along the east bank of North Creek from Northeast 205th Street to Monte Villa Parkway. 2.4.6 Revision 6 Tolt River and Upper South Fork Snoqualmie River No additional information available in Revision 6. 2.4.7 Revision 7 Snoqualmie River and Issaquah Creek No additional information available in Revision 7. 2.4.8 Revision 8 Cedar River - One additional flood protection measure was identified along the river. This feature, a floodwall constructed by the City of Renton in 2000 to protect the old city hall, extends along the left riverbank just upstream of the library. The floodwall is not certified to FEMA standards, and was consequently disregarded for this flood study. No other flood protection measures exist within the study reach. Kelsey Creek - The only flood protection measures along the study reach occur along the main stem of Kelsey Creek in Kelsey Creek Park. Here, along the right bank, a 500-foot long earthen embankment approximately 7 feet in height was constructed to keep overtopping flows within Kelsey Creek from entering a low- lying swale area immediately to the west. At one time, Kelsey Creek was actually located in this swale reach, but was later shifted east to its current alignment. Because this embankment fails to meet FEMA's certification requirements, it was not considered to provide flood protection, and was effectively not included in the analysis. 66 Patterson Creek - No major structural flood protection measures exist or are planned along Patterson Creek. Green River – The Lower Green River is confined within natural banks or constructed levees over almost its entire length downstream of State Route 18. The King County facility inventory includes approximately 30 separately-named levees or revetments within the study area. Of these, however, only the left bank levee in the Southcenter area (RM 11 to RM 17) is a USACE certified flood protection levee. This certified levee is commonly referred to as the Tukwila 205 levee. The remaining levees are not certified and the hydraulic analyses described herein consider the effects on flood inundations of both "with levee" and "without levee" scenarios. Interior drainage for much of the Green River floodplain is accomplished via pump stations. The three most significant pump stations in the valley are the Black River (PI) Pump Station (BRPS), the Southcenter (P 17) Pump Station, and the Horseshoe Acres Pump Station. The first two of these pump stations are operated by King County and have design capacities of about 2,900 cfs and 100 cfs respectively. The Horseshoe Acres pump station is operated by the City of Kent and has a discharge capacity of approximately 67 cfs. Numerous smaller pump stations also drain the areas behind the Lower Green River levees. These include the Strander Boulevard, South 180th Street, Washington Avenue, Union Pacific, and South 3rd Avenue Pump Stations. The only significant structural flood protection measure along the Middle Green study reach is a levee along the left bank of the river between RM 34.5 and RM 35.0, near the SE Green Valley Road Bridge. This levee is not certified and the hydraulic analyses described herein consider the effects on flood profiles of both ―with levee‖ and ―without levee‖ scenarios. 2.4.9 Revision 9 Puget Sound No additional information to add. Sammamish River - The most significant structural flood protection measures along the Sammamish River are the in- channel weir at Marymoor Park and berms located along the river banks, principally between Leary Way, near the City of Redmond, and Northeast 145th Street, near the City of Woodinville. These berms act like levees, containing water in the main channel and 67 preventing it from reaching overbank areas. However, these berms are not certified levees and have never been accredited by FEMA. Further discussion of the modeling approach taken for these berms is found in Section 3.2.9 Hydraulic Analysis. White River- The only significant structural flood protection measures within the studied reach of White River are two small, privately built levees along the right bank of the river, near RM 26.4 and the other near RM 24.0. Neither of these levees is certified and hydraulic analyses indicate that both would be overtopped by the base flood. Therefore, it was not necessary to run ―with‖ and ―without‖ levee simulations as the base flood mapping in the area landward of these levees would be the same in either case. 3.0 ENGINEERING METHODS For the flooding sources studied by detailed methods in the community, standard hydrologic and hydraulic study methods were used to determine the flood-hazard data required for this study. Flood events of a magnitude that is expected to be equaled or exceeded once on the average during any 10-, 50-, 100-, or 500-year period (recurrence interval) have been selected as having special significance for floodplain management and for flood insurance rates. These events, commonly termed the 10-, 50-, 100-, and 500-year floods, have a 10-, 2-, 1-, and 0.2-percent chance, respectively, of being equaled or exceeded during any year. Although the recurrence interval represents the long-term, average period between floods of a specific magnitude, rare floods could occur at short intervals or even within the same year. The risk of experiencing a rare flood increases when periods greater than 1 year are considered. For example, the risk of having a flood that equals or exceeds the 1-percent-annual-chance flood in any 2-percent annual chance period is approximately 40 percent (4 in 10); for any 90-year period, the risk increases to approximately 60 percent (6 in 10). The analyses reported herein reflect flooding potentials based on conditions existing in the community at the time of completion of this study. Maps and flood elevations will be amended periodically to reflect future changes. 3.1 Hydrologic Analyses Hydrologic analyses were carried out to establish peak discharge- frequency relationships for each flooding source studied by detailed methods affecting the community. For those flooding sources being restudied or that are extensions of previous detailed riverine studies, peak discharge results presented in the previous Flood Insurance Studies for King County and the Cities of Auburn, Kent, and Renton (References 1, 2, 8, and 15) were compared with updated discharges estimated to determine the appropriate values to be used in this revised study. The peak discharge estimates assume that 68 existing basin hydraulic structures remain unobstructed and existing upstream dams or impoundment structures remain intact with no changes in operating characteristics. Discharge-frequency for the Snoqualmie River, South, Middle, and North Forks Snoqualmie River, Sammamish River, North Creek, Bear Creek, Evans Creek, Issaquah Creek, North and East Forks Issaquah Creek, Tibbetts Creek, Vasa Creek, Cedar River, Mercer Creek, Right Channel Mercer Creek, Richards Creek, East and West Tributaries Richards Creek, Kelsey Creek, West Tributary Kelsey Creek, East Branch of West Tributary Kelsey Creek, North Branch Mercer Creek, McAleer Creek, Coal Creek, Lyon Creek, Meydenbauer Creek, North Fork Meydenbauer Creek, South Fork Skykomish River, Maloney Creek, and the Tolt River were developed from USGS stream gaging stations on the respective streams by applying the standard log-Pearson Type III methods with the expected probability correction as outlined by the U.S. Water Resources Council (Reference 31). Discharge-frequency relationships in the revised study for Raging River, Issaquah Creek, Cedar River, Swamp Creek, May Creek, May Creek Tributary, and Big Soos Creek were developed from streamflow records at USGS gages within those watersheds. The gage reference numbers, descriptions, and periods of record (Reference 32) used in the analyses are summarized below. That listing includes additional gages used for correlating and transferring flows between local, hydrologically similar basins or for comparison of results. The Flood Flow Frequency Analysis computer program (Reference 15) was used to determine the discharge- frequency relationships by applying log-Pearson Type III analysis techniques in accordance with methods presented in USGS Bulletin 17B (Reference 33) to the annual peak flow data for each gage site. Table 1 below shows the gage record data that were used for the original studies only. The studies subsequent to the original studies should have used more updated gage record information for flood flow estimations. Table 1 - USGS GAGES Flooding USGS Gage Period of Source Ref. No. USGS Gage Description Record Snoqualmie River 12-1490 Near Carnation 1930-1965 N/A Near Snoqualmie Falls 1929-1965 12-1445000 Near Snoqualmie Falls 1959-1978 South Fork Snoqualmie River N/A At North Bend 1911-12, 1914-16, 1918-26, 1930-38, 1946-50, 1961-78 Table 1 – USGS GAGES (Continued) 69 Flooding USGS Gage Period of Source Ref. No. USGS Gage Description Record South Fork 1910-12,1914-18 Snoqualmie River 1920, 1922-26 (continued) North Fork Snoqualmie River N/A Near North Bend 1930 Middle Fork Snoqualmie River N/A Near Tanner 1962-1978 Raging River 12-145500 Near Fall City 1946-1985 Tolt River 12-148500 Near Carnation 1959-1971 Green River N/A Near Tukwila 1959-1963 N/A Near Auburn 1937-1962 N/A Near Black Diamond 1940-1948 Big Soos Creek 12-112600 Above Hatchery, Near Auburn 1961-1986 Sammamish River 1250 At Bothell 1940-1963 N/A Near Redmond 1940-1957 Swamp Creek 12-127100 At Kenmore 1964-1986 Little Bear Creek 12-126000 North Creek, Near Bothell 1946-1976, 1986 Bear Creek 12-122500 Near Redmond 1946-49, 1980-81, 1986 12-124500 At Redmond 1946-50, 1956-58, 1986 12-124000 Evans Creek, Above Mouth Near Redmond 1956-1977 Issaquah Creek 12-121600 Near Mouth 1964-present 12-121000 Near Issaquah 1946-1964 May Creek 12-119600 At Mouth, Near Renton 1965-1979 Cedar River 12-119000 At Mouth 1946-1985 12-1175 Near Landsburg 1948-present McAleer Creek 12-1276 At Lake Forest Park 1963-72, 1973-74 Mercer Creek N/A At Bellevue 1945-present Flooding USGS Gage Period of Source Ref. No. USGS Gage Description Record Table 1 – USGS GAGES (Continued) 70 Beckler River 12-1310 Near Skykomish 28 years Discharge-frequency relationships established for gage locations were transferred to selected runoff concentration points along the study reaches through the application of regional regression techniques per published regression equations (Reference 34). USGS gage flow records from the adjacent, hydrologically similar North Creek basin were used to establish flow estimates for Little Bear Creek. Evaluation of peak recurrence interval discharges in the lower reaches of Little Bear Creek, downstream of the State Route 202 crossing, include reductions in main channel flow to reflect overflows away from the main channel that enter the Sammamish River at other locations. Updated hydrology for flooding sources either being restudied or that are extensions of existing detailed studies were compared using statistical confidence limits with existing published Flood Insurance Study discharges at identified locations. Comparison of peak discharge estimates for the May Creek gage site with those published in the previous Flood Insurance Study for the City of Renton indicated no significant statistical differences. Therefore, in accordance with FEMA guidelines, the previous flow estimates for the gage site have been used in the present study. Recurrence interval peak discharge estimates established for the added detailed study reach of Bear Creek, upstream from its confluence with Cottage Lake Creek, are based on the results of the statistical analysis of annual peak flows at USGS gage No. 12-122500 near Redmond. The limited period of gage record (8 years, including January 1986 event provisional flow estimates) would normally preclude analysis using this method. However, additional gages located on Cottage Lake Creek (No. 12-123000), Evans Creek (No. 12-124000), and on the downstream reach of mainstream Bear Creek, (No. 12-124500) provided adequate data for comparative assessment of results. Discharge-frequency relationships for Thornton Creek, Longfellow Creek, Mill Creek (Auburn), and Rolling Hills Creek were developed using the USACE HEC-1 computer program (Reference 35). The basic application of this synthetic hydrograph model included computation of drainage Flooding USGS Gage Period of Source Ref. No. USGS Gage Description Record Mercer Creek N/A At Bellevue 1949-present South Fork Skykomish River 12-1330 Near Index 69 years 12-1305 Near Skykomish 26 years 71 subbasin runoff hydrographs using the NRCS Type 1A storm distribution (Mill Creek and Rolling Hills Creek), routing of those hydrographs through channel reaches and detention storage areas, and combining them with downstream subbasin hydrographs at selected study reach runoff concentration points. Calibration of those models to discharge estimates, developed from high water mark data collected for the January 1986 event, was performed. Peak-flow estimates for Thornton Creek include consideration of unobstructed diversion of flows to the overflow pipeline to Lake Washington. Runoff estimates for Thornton and Longfellow Creek used a multiple peak design storm distribution pattern based on the actual January 17 through 19, 1986, storm event, taken from a network of local precipitation gage data (Reference 36). In addition to localized culvert backwater routing effects, routing of flows through the SW Webster Street detention basin and outlet structure was included in the Longfellow Creek modeling analyses. Discharge estimates computed at the mouth of Mill Creek (Auburn) consider noncoincidence of peak flows in the Green River and Mill Creek. Storage routing effects of backwater storage at the location have therefore not been considered in this analysis. Discharge estimates for Mill Creek for the floodway determination were modified to reflect reduction in storage with encroachment on the storage provided by the natural floodplain. Recent modeling analyses of the Mill Creek (Kent) and the Springbrook Creek basins using the NRCS TR-20 hydrograph program have been performed by a local consultant for the City of Kent Drainage Master Plan (Reference 37). That study developed 25-year and 1-percent-annual- chance recurrence interval discharge estimates based on a 12-hour duration, NRCS Type 1A storm distribution for the valley floor basins. It included consideration of significant storage-routing components within the Mill/Springbrook Creek system, including the recently completed Earthworks Park stormwater detention facility. The discharge estimates presented in the City of Kent Drainage Master Plan and supplemental computer output files for existing land use conditions have been accepted for use in this restudy. Additional recurrence interval flows were extrapolated from computer flows. The resultant flow estimates were reduced by overflow estimates to Springbrook Creek north of James Street, computed using hydraulic backwater rating methods, to provide the downstream estimates. Stream gage records are not available for the Black River and Springbrook Creek. In the absence of gaged discharge data for statistical determination of peak flow estimates, information from several previous hydrologic modeling studies within the Black River basin were collected and reviewed for comparison of results and for determination of acceptability 72 for use in the restudy. Synthetic unit hydrograph modeling of basin runoff has been performed by the USACE using the HEC-1 Flood Hydrograph model (Reference 38); the NRCS using the TR-20 model (Reference 39); by the previous study contractor for the existing Renton Flood Insurance Study using the TR-20 model (Reference 15); and, more recently, by other consultants for upstream reaches of the basin, using the TR-20 model. The flow estimates from the previous Flood Insurance Study were determined to be the most representative of the conditions existing in the basin at the time of this restudy, and were therefore used. Since the previous Flood Insurance Study only calculated the 25- and 100-year hydrographs, the 0.2-percent-annual-chance hydrograph was interpolated from those previously computed. The 0.2-percent-annual-chance hydrograph was not analyzed because of the extensive changes in overbank storage that occur at P1 pond stages in excess on the 1-percent- annual-chance recurrence interval. The Green River basin has been studied extensively by the Seattle District of the USACE. The USACE operation of Howard A. Hanson Dam provides flow regulation for flood protection to the downstream river reaches, particularly the lower Green River Valley downstream from Auburn. Current USACE operation of the dam regulates the peak downstream flow releases up to the standard project flood to 12,000 cfs at the USGS Auburn gage. This includes consideration of tributary inflows downstream of the dam (i.e., Newaukum Creek and Big Soos Creek). Discharge-frequency analyses have been performed by the USACE as part of the Green River Flood Reduction Study (Reference 23) for estimation of peak unregulated and regulated floodflows at the Auburn stream gage. Results of those analyses were reviewed and used in this restudy. The flows are also in agreement with previously published Flood Insurance Study discharge estimates. Discharge-frequency relationships for the White River were obtained from a backwater channel-capacity study by the USACE (Reference 40). The selected stations were Mud Mountain Dam and the White River at the mouth. The peak discharges were adjusted for the White River near Auburn. Those adjusted discharges were used directly for this study. Because there are no streamflow records on Forbes Creek and Yarrow Creek, runoffs for the floods of interest were calculated using rainfall relationships developed for the area and a computerized stormwater routing model. The model incorporates the unit hydrograph methodology developed by the NRCS (Reference 41). The peak discharges obtained by this method were comparable to those derived from regional regression equations published by the USGS (Reference 42). 73 The hydrologic analysis of Miller and Walker Creek in the Sea-Tac communities plan (Reference 43) used a stormwater management model developed in earlier river basin studies. A single large storm and measurement at temporary gaging stations along the creeks were used to calibrate the model, and flows for the 10-, 2-, and 1-percent-annual-chance storms were computed. The 0.2-percent-annual-chance flood was estimated by extending the curve through the computed points. A gaging station on Miller Creek was established in 1973 to provide a better understanding of hydrologic conditions in the stream. No gage records exist for Des Moines Creek. Because of highly similar drainage basin characteristics, peak discharges per square mile for Miller and Walker were applied to the Des Moines Creek drainage basin. These flows gave flood elevations well in excess of local experience. The excessive flow rates were explainable because an 80-foot-high road embankment (Marine View Drive) crosses Des Moines Creek Canyon at the upper end of the detailed study area. The box culvert flowing under the embankment has a capacity of 300 cfs before peak flow storage begins. However, even assuming that no outflow was allowed, the impoundment can store 65 percent of the runoff that would occur during a 6-day, 1-percent-annual-chance storm. Therefore, reservoir routing capacity exists to significantly reduce peak flows. Utilizing rainfall-runoff data and techniques developed by the study contractor during a recent study of a similar urban area located several miles to the north, a 1-percent-annual-chance synthetic runoff hydrograph was developed for a 6-day storm for Des Moines Creek. The 1-percent-annual-chance hydrograph was routed through the storage reservoir created by the road embankment, reducing the unrouted peak discharge. This same percentage of flow reduction was applied to the 10-, 2-, and 0.2-percent-annual-chance unrouted peak flows. 3.1.1 Revision 1 Miller Creek - Miller Creek passes through several communities as it flows downstream to Puget Sound. The upper end of the study reach passes through the newly formed City of SeaTac. About mid-reach, the channel passes under Des Moines Way (near State Route 509) and enters unincorporated King County. Downstream of 1st Avenue South, near 6th Avenue SW, the channel enters the City of Normandy Park and remains within the city limits until it empties into Puget Sound. Land neighboring the stream channel is occupied by private residences and forest, farm, and pasture lands. 74 The average annual precipitation, as recorded at the nearby Seattle- Tacoma International Airport, is approximately 38 inches. The heaviest rainfall occurs during the months of November through January, with little rainfall during the summer months of July and August. The average annual temperature is 50°, with average daily high of 59°F and lows of 44°F. July and August are the warmest months, with average daily maximum temperatures of 75°F, while January is the coldest, with average daily minimum temperatures of 34°F. Estimation of flood discharges along Miller Creek and its tributaries was based on a previous study performed by nhc in 1990 for the King County Division of Surface Water Management (Reference 95). In this study, the Environmental Protection Agency’s Hydrologic Simulation Program – FORTRAN (HSPF) model (Reference 96), was used to describe the hydrology of the Miller Creek basin. HSPF is a state-of-the-art hydrologic simulation model that is rapidly becoming the model of choice for simulating streamflow values by many government and private agencies. The model was used to compute time series of streamflows estimated from observed rainfall, evaporation, and soil-characteristic data. The model included the effect of the Lake Reba Regional Stormwater Detention Pond, which was constructed in 1992 near the headwater of Miller Creek. The Miller Creek basin HSPF model was calibrated using 2 years of recorded streamflow data collected at a gage near the Southwest Suburban Sewer District treatment plant, recorded precipitation at the National Weather Service SeaTac weather station, and evaporation data from the Puyallup station. Calibration was performed for current basin land-use conditions. To develop flood-frequency curves, the calibrated model was then used to stimulate Miller Creek streamflows. A time series of streamflow values was created for the 29 years between October 1, 1961, and January 11, 1990, using historical SeaTac precipitation and Puyallup evaporation data. Log-Pearson III distributions were fit to the annual peaks from the simulation to determine the 10-, 2-, 1-, and 0.2-percent-annual-chance flood discharges for Miller Creek. It should be noted that considerable extrapolation was required to determine the 1-, and 0.2-percent-annual-chance flow rates. The areas of Tub Lake Tributary make up part of the total of 22 subbasins of the main stem of Miller Creek. Flood estimates for the Tub Lake Tributary were also computed using the HSPF model. 75 3.1.2 Revision 2 Snoqualmie River - No additional information to add. 3.1.3 Revision 3 Raging River - The discharge values for the downstream reach were developed using a statistical analysis of the stream-gage data at USGS Gage No. 12145500 along the Raging River. The period of record from 1945 to 1992, plus an historic event in 1932, was used in the analysis. The discharge values from this revised hydrologic analysis are significantly higher than the discharge values from the Summary of Discharges Table in the previous Flood Insurance Study for King County, Washington and Incorporated Areas, dated September 29, 1989 (Reference 94), which were used in the detailed study performed by CH2M HILL, Inc., for the reach upstream of I-90. Therefore, FEMA revised the discharge values for the upstream reach using drainage area- discharge relationships established in the detailed hydrologic analysis for downstream reach. 3.1.4 Revision 4 North Fork Issaquah Creek - North Fork Issaquah Creek originates in King County just northeast of the City of Issaquah and flows in a mostly southwesterly direction to the main stem of Issaquah Creek. The contributing basin area is 4.5 square miles, ranging in elevation from approximately 60 feet near the mouth to a maximum elevation of approximately 1,200 feet. Much of the upper basin was forested as of 1989. Since then, the major ―Klahanie‖ urban development has largely been completed and covers most of the northern side of the upper basin. A second major urban development, ―Grand Ridge,‖ is presently in the planning stages and will cover most of the southern side of the upper basin. Flows estimated using the HSPF model are based on a model that was calibrated to streamflow data collected on North Fork Issaquah Creek for the years 1988 through 1990, based on the forested land-use conditions that existed. Peak flows from the calibrated HSPF model are substantially lower than other estimates primarily because the basin contains proportionally more highly permeable outwash soils than other gaged basins in the regions. Revisions to the King County HSPF model were made as part of the restudy to reflect major residential developments that have 76 been constructed since 1989 and others that were in the planning stage as of 1995. The Klahanie and Grand Ridge developments will cover essentially all of the upper basin area. Both of these developments are located primarily within the North Fork Issaquah Creek basin, but extend across basin boundaries into other basins as well. The Klahanie project is an 856-acre development located in the upper North Fork basin north of the Issaquah Fall City Road and covering approximately 25 percent of the North Fork basin (Reference 101). Construction for this development began in 1987 and was nearly complete as of 1995. Stormwater peak flows are controlled through a series of detention ponds including a major facility developed by construction of a control structure at the outlet of Yellow Lake within the development area. The stormwater facilities for the Klahanie development, and the Yellow Lake outlet control in particular, were designed so that peak flows leaving the site would not be increased as a result of the development. The Grand Ridge project is a proposed 2,200-acre development located in the upper North Fork basin south of the Issaquah Fall City Road and which will cover approximately 50 percent of the North Fork basin. Environmental Impact Statement hearings for this project were in progress during 1995. Discussions with the project’s engineers revealed that stormwater control is planned to be provided entirely through infiltration systems, which will preclude peak flows from developed areas being released directly to the stream system. With infiltration systems, the Grand Ridge development is not expected to cause any significant increase in peak flows in the North Fork basin. While updating the HSPF model, it was discovered that the major stormwater detention control facility at Yellow Lake had been constructed in 1987 in advance of most other Klahanie development activity, but had not been included in the original HSPF model. Calibration of the original model had been attained to some extent by adjusting the model’s previous surface runoff parameters to reflect the flow attenuation effects actually caused by the outlet controls at Yellow Lake (Reference 102). Because of the changing land use, neither the original calibrated HSPF model nor the revised model with 1989 land use are directly suitable for estimating flood discharges for 1995 conditions. The original flood frequency curve for the calibration period is artificially suppressed because of the timing of the HSPF 77 calibration in relation to phasing of the Klahanie development: the Yellow Lake stormwater facility had been constructed, but the development to be serviced by that facility had not. The flood frequency curve from the revised model with 1989 land use underestimates the calibration-period flows by about 25 percent. For purposes of the restudy, it is assumed that flows from the ―HSPF Model Revised, 1995 Land Use‖ underestimate actual flows by 25 percent. The 25-percent value is based on the peak- flow reduction that resulted when the original calibrated model based on the 1989 land use was revised to include the Yellow Lake outlet control. For the restudy, a 1-percent-annual-chance discharge of 315 cfs was used near the mouth of North Fork Issaquah Creek. Flood discharges in the lower portion of the restudy reach are supplemented by floodwater originating from the main stem Issaquah Creek. Main stem Issaquah Creek channel overtopping between the I-90 crossing and the confluence with the North Fork channel is shown by high-water-mark information to have occurred during the November 1986 flood, and probably also the January 1990 flood, which had a nearly identical main-channel discharge (Reference 103). These floods each have a return interval of approximately 30 years. Water that overtops the right bank of the main stem Issaquah Creek channel downstream of the I-90 crossing will flow toward the North Fork channel. Bear Creek - Most of the Bear Creek study reach lies along Avondale Road NE, which is the extension of State Route 520. Avondale Road NE runs primarily north-south and crosses Bear Creek at three locations approximately at River Miles 1.4, 5.4, and 5.7 (Reference 107). The most upstream Avondale Road NE crossing is the upstream limit of the restudy. Bear Creek originates in an extensive network of wetlands near Paradise and Echo Lakes in southern Snohomish County, and flows primarily southward for approximately 14 miles to its confluence with the Sammamish River (Reference 105). The contributing drainage area is approximately 51 square miles at its mouth. The lower portion of the restudy reach flows through a flat floodplain that ranges in width from approximately 250 feet wide downstream of Union Hill Road to nearly 1,800 feet wide downstream of the confluence of Bear and Evans Creeks. Most of the lower portion of the floodplain is bounded by road or business park fills including those of State Routes 202 and 520, Union Hill Road, Avondale Road Extension, Avondale Road NE, Bear Creek 78 Business Park (Harvard College), and Redmond Village. Beginning approximately 0.5 miles upstream of the confluence with Evans Creek, the Bear Creek floodplain is generally narrower, ranging between 200 and 350 feet wide, bordered by gentle, rolling hills. Some flow may overtop sections of Union Hill Road upstream of Avondale Road NE. Although the area near Union Hill Road is presently developed, these flows were assumed to be relatively minor. South Fork Skykomish River - The peak discharge-frequency relationships for the reach of the South Fork Skykomish River below the confluence with Beckler River were developed using a statistical analysis of the stream-gage data from the Index, Washington gage (No. 12133000). This gage has a total of 74 records for the water years ranging from 1897 through 1982. The hydrologic analysis for the South Fork Skykomish River upstream of the confluence with Beckler River was based on the annual peak-flow data from the Skykomish gage (No. 12130500), with 26 years of record from water years 1930 through 1970. The floodplain boundaries along the South Fork Skykomish River in Snohomish County are based on an approximate study and do not match those from the detailed study in King County at the county line. Middle Fork Snoqualmie River - The hydrologic analysis for Middle Fork Snoqualmie River was based on flow rates from the previous effective FEMA study. North Fork Snoqualmie River - The hydrologic analysis for the North Fork Snoqualmie River was based on peak-flow gage data on the river from the gages near North Bend, Washington (No. 12143000), and Snoqualmie Falls, Washington (No. 12142000). The North Bend gage includes 43 records from 1909 to 1978. The Snoqualmie Falls gage includes 61 peak records from 1930 to 1992. 3.1.5 Revision 5 North Creek - Peak discharge-frequency relationships for the revised reach of North Creek were determined from the hydrologic computer model developed for the original study of North Creek using the U.S. Environmental Protection Agency HSPF model (Reference 119). For the original study, the North Creek HSPF model was run with 39 years of 15-minute rainfall and daily 79 evaporation to develop flood-frequency curves. The resulting 39- year time series of simulated North Creek stream flows were used to create 39 years of annual instantaneous peak flow data at four locations along the study reach. A Log-Pearson Type III distribution was fitted to the annual peaks using the procedures of Water Resources Council Bulletin 17B, and the magnitudes of flows with return periods of 10-, 2-, 1-, and 0.2-percent-annual- chance flows, respectively, were determined. Two small streams were identified for study by approximate methods. Horse Creek originates in a steep, wooded gully near the northern corporate limits and drains approximately 1 square mile. It flows through downtown Bothell in a series of culverts, ditches, and closed pipes. The unnamed creek that flows north along 96th Avenue Northeast drains approximately 0.6 square miles of wooded area south of the Sammamish River (Reference 122). 3.1.6 Revision 6 Tolt River - The hydrologic analysis for the Tolt River was based on a statistical analysis of peak-flow data from the gage near Carnation, Washington (No. 12148500). This gage has a total of 58 water years of record: 1929, 1931, and 1938 through 1993. Upper South Fork Snoqualmie River – The hydraulic analysis of Upper South Fork Snoqualmie River upstream of the I-90 bridge was initially performed by Harper Righellis Inc. The data prepared by Harper Righellis were incorporated into analyses performed by the USACE and revised where necessary. Middle and South Fork Snoqualmie River - Hydrologic analysis records for the various gages on the Snoqualmie River system were intermittent. Missing data in the intermittent records were synthetically reconstituted using the USACE Regional Frequency computer program HEC-REGFRQ (Reference 124). This program fills in and extends the records for all gages using flow data at nearby long-record stations. All stations above the Snoqualmie near Carnation station were included in the initial HEC-REGFRQ analysis. This initial HEC-REGFRQ analysis significantly improved the station statistics (primarily the regression coefficient and equivalent record length) for all stations except the Snoqualmie near Snoqualmie gage. Therefore, this station was eliminated from the analysis and the final HEC-REGFRQ analysis included only the gages on the South Fork. The reconstituted period of record for these gages was 89 years, from approximately 1909 to 1997. 80 A two-station comparison with the long-term gage at Carnation was used to extend the record for the short-term gage at Snoqualmie. Log-Pearson Type III frequency curves were computed for all the gages with the USACE Flood Frequency Analysis computer program HEC-FFA (Reference 125) using the reconstituted HEC- REGFRQ data as input for the gages on the North, Middle, and South Forks. The extended record from the two-station comparison was used as input for the gage on the mainstem of the Snoqualmie River near the City of Snoqualmie. Discharges at locations other than the gages were computed using drainage area ratio equation with the nearest gage. The resultant frequency curves were compared with previously published discharges in the Flood Insurance Study. With a few minor exceptions, the previously published discharges for the South Fork gages at the City of North Bend fell within the 25 percent and 75 percent confidence limits of the newly computed frequency curves. Therefore, the previously published discharge for the North Bend station was adopted for this restudy. 3.1.7 Revision 7 Snoqualmie River - The hydrologic analyses for this restudy were based on the USACE study completed in December 1998. The hydraulic analyses were performed by Harper Houf Righellis Inc. and completed in October 2001. This restudy effort was identified in Cooperating Technical Community Memorandum of Agreement dated September 26, 2000, between King County and FEMA. Regulatory floodways were computed for all studied reaches of the Snoqualmie River; however, only the 1-percent-annual-chance flood event was analyzed for Ribary Creek and Gardiner Creek. Hydrologic analyses were performed to establish peak discharge- frequency relationships for each flooding source affecting the communities that was studied by detailed methods. This hydrologic analysis was completed by Harper Righellis subsequent to Revision 6 (See section 3.1.6.). The peak flows used in the steady-state analysis for the three forks of the Snoqualmie River were derived from values previously accepted by FEMA, based on the hydrologic analyses performed 81 by the USACE, Seattle District, for South Fork, as described in Section 10.6. The peak flows for Gardiner Creek and Ribary Creek were not based on runoff from their catchments, both of which are 1.3 square miles, but rather from an overflow of South Fork through an assumed breach in the left levee. At the downstream end, the 1-percent-annual-chance discharge for Ribary Creek used for this restudy is 2,675 cfs, which is the combined South Fork overflow and the Ribary Creek flow. At the upstream end, the combined South Fork overflow and the Ribary Creek peak flow is 2,950 cfs. The Gardiner Creek 1-percent-annual-chance discharge at the downstream end is 575 cfs, which combines Gardiner Creek, South Fork, and the Ribary Creek split flow. The Gardiner Creek split of the combined South Fork overflow and Ribary Creek flow is 275 cfs (Reference 130). Discharges are shown in tabular format in Table 2. Issaquah Creek - Hydrologic analyses were performed to establish updated recurrence interval peak discharge estimates for Issaquah Creek and East Fork (Reference 134). For those flooding sources being restudied or those that are extensions of previous detailed riverine studies, peak discharge results presented in the previous FIS for King County and in the Issaquah Creek Basin Plan (Reference 135) were compared to updated estimated discharges to determine appropriate values for this revised study. The peak discharge estimates assume that existing basin hydraulic structures remain unobstructed and that existing upstream dams or impoundment structures remain intact, with no changes in operating characteristics. Discharge-frequency analysis in this revised study for Issaquah Creek and East Fork were performed as described in the hydrologic memorandum completed for this study (Reference 134). The Flood Flow Frequency Analysis computer program HEC-FFA (Reference 136) was used to determine the discharge- frequency relationships by applying log-Pearson Type III analysis techniques, in accordance with methods presented in the USGS publication Guidelines for Determining Flood Flow Frequency, Bulletin 17B (Reference 137) to the annual peak flow data for the gage sites. The resulting flood flow frequency results for the Issaquah Creek gages and reported/adjusted periods of record were compared to previously published flood flow frequency values. In accordance 82 with Bulletin 17B guidance, a generalized skew of -0.02 was used as a HEC-FFA input parameter applicable for this region. Flood flow frequency analyses also were completed for the period 1964-75 in an attempt to validate the published FEMA record. The computed 1-percent-annual-chance peak flow result was much lower (2,990 cfs) than the 1-percent-annual-chance peak flow previously published (4,700 cfs). The expected probability estimate of 3,410 cfs was also considerably lower. The revised flood flow frequencies were used because the difference compared to the previous flood flow frequencies was statistically significant. The updated flood flow frequency results computed at Gage 12121600 were adopted for the FIS restudy. (The actual record used was for the period 1964-99 with some updates and was based on no loss of flow from Issaquah Creek.) Flood flow frequency on East Fork could not be analyzed directly because of the limited stream gage record. Therefore, confidence limits could not be computed to measure against the standard FEMA criteria for acceptance of prior or new flood flow estimates. Considering the similarities in peak flow between the King County Basin Plan Modeling Results (for existing conditions) and the flood flows estimated from gage transfer (using USGS gage 12120600), the higher of those two flow estimates was adopted. Additional documentation of the hydrologic analysis procedures and results are found in the hydrologic analysis memorandum (Reference 134). Discharge-frequency relationships established for gage locations on the creeks were transferred to selected runoff concentration points along the study reaches through the application of standard USGS methods for transfer of peak flow records (Reference 138). An analysis of streambank overflows was conducted at five locations along Issaquah Creek (Reference 139). On Issaquah Creek, recurrence interval overflows were taken into account to establish peak flow estimates for downstream reaches. Overflows are located at the Pickering reach, two places along the Gilman reach, the Dogwood Street bridge, and the Newport Way bridge. An overflow path upstream of Gilman Boulevard was rated, and a separate overflow model was developed that extends approximately 0.6 miles downstream (northwest) of the main channel. 83 Two overflow paths were identified on East Fork, one located on the west bank upstream of the Dogwood Street bridge and the Crescent Drive footbridge. The discharges for the stream studied by detailed methods are shown in Table 2, ―Summary of Discharges.‖ However, the following estimates account for current loss of flows upstream and downstream of Gilman Boulevard. 3.1.8 Revision 8 Cedar River – City of Renton Area - The City of Renton provided the peak discharge values used herein to nhc. The flow values were developed by King County (King County, March 2000). The 10-, 2-, 1-, and 0.2-percent-annual-chance flows (see Table 2) were based on a flood frequency analysis of approximately 80 years of peak flow data, fit with a Log-Pearson III distribution. Cedar River – King County Unincorporated Area - The hydrology developed by King County in March 2000 was first used by Harper Righellis for the Unincorporated King County study of the Cedar River and then, subsequently utilized in the LOMR for the City of Renton. Kelsey Creek - Flood frequency quantiles for current conditions on Kelsey Creek and the West Tributary were estimated using a Hydrologic Simulation Program - Fortran (HSPF) model originally developed by nhc, and later updated by City of Bellevue staff. Patterson Creek - Hydrologic analyses were conducted out to establish the peak discharge-frequency relationship for Patterson Creek. A Hydrologic Simulation Program FORTRAN (HSPF) rainfall-runoff model was developed, calibrated, and applied to simulate a 57-year record of flows for the basin. Annual peak flows were extracted from the model at seven locations along the study reach and flow quantiles at each location were estimated by fitting flood frequency curves to these data. The estimated 10-, 2-, 1-, and 0.2-percent-annual-chance floods for existing land use conditions are summarized in Table 2. Snoqualmie River - The objective of the hydrologic analysis in this study was to develop 10-, 2-, 1-, and 0.2-percent-annual- chance (i.e. ―N‖-year) design flood hydrographs for input to the HEC-RAS unsteady hydraulic model at all model inflow points. Design flood hydrographs were developed for eleven inflow locations along the Snoqualmie River portion of the study area. Inflow points include the upstream boundaries of each river, major 84 tributaries, and areas contributing significant direct discharge to the rivers. Design event inflow hydrographs were developed using a process that included model calibration, application of the model to simulate a wide range of historic flood events, stage frequency analysis on the resultant historic flood stages at key locations, and then refinement of the N-year design event hydrologic inputs to achieve reasonable concurrence with the corresponding N-year stages at the key locations. Inflow hydrographs from sixteen of the largest flood events that occurred between water years 1966 and 2003 were synthesized for input to the hydraulic model. The primary source of these flow data were USGS observed flow records. Where USGS data was not available, a range of methods were utilized to estimate historical flood hydrographs at the hydraulic model inflow points including gage data transposition, rainfall-runoff modeling, and reservoir operations modeling. Each of the sixteen historic floods was then simulated using the HEC-RAS unsteady hydraulic model. For water years in which two significant flood events occurred, both were simulated and the highest stage at each key location was retained. The resultant peak stages were then plotted on frequency paper and stage frequency curves were drawn through the data. Of all of the floods simulated with the hydraulic model, two were found to produce stages that most closely corresponded to certain N-year stages at key locations throughout the study area. Peak stages produced by the December 1977 flood simulations most closely approximated 10-percent-annual-chance stages in the study area while the November 1990 flood simulations resulted in river stages that most closely matched 2- and 1-percent-annual-chance conditions. November 1990 is also the largest flood within the USGS’s systematic gage record, and best suited for developing 0.2-percent-annual-chance design hydrographs. Consequently, historical inflow hydrographs for these two historic floods with relatively small adjustments were used to produce the N-year design input hydrographs for floodplain mapping, floodway analysis, and discharge quantile estimation. The resultant discharge quantiles are summarized in Table 2. These data represent the peak flows simulated in the hydraulic model at the listed locations using the corresponding design event model. The listed locations were included in Table 2 because the USGS operates a stream gage at each of the sites, allowing for easy 85 comparison with the often reported discharges. It should be noted that during large flood events, water escapes the main channel at the Carnation and Duvall gages. Therefore, discharge quantiles at these sites is further divided into discharge remaining in the main channel and that passing by the gage in the overbank. Springbrook Creek - Springbrook Creek drains a basin of approximately 25 square miles located in a highly urbanized area of western King County, Washington. The basin is bounded on the west of the Green River levee system and on the east by the uplands of the Soos Creek basin. The creek drains portions of the cities of Kent, Renton, Tukwila and unincorporated King County; however, Kent to the south and Renton to the north are by far the largest areas within the basin. Green River – Hydrologic analyses were conducted to establish the peak discharge-frequency relationship for the Lower Green River. Annual peak flows for the post Howard A. Hanson Dam period (1961-2007) were obtained from the USGS for the Green River near Auburn (USGS gage 12113000) and flow quantiles were estimated by fitting flood frequency curves to these data. Because flood flows in the study reach are highly controlled by regulation at Howard A. Hanson Dam (HAHD), the applicability of traditional flood frequency analysis techniques may be questionable. Therefore an alternative, "target flow plus residual" model was also conceptualized and applied to estimate peak discharge quantiles at the Auburn gage. The estimated peak discharge quantiles at the Auburn gage were then transposed to other locations and adjusted to account for flow attenuation in the Mill Creek/Mullen Slough floodplain plus other inflows within the study reach. In addition to the peak discharge quantiles, discharge hydrographs for the 1-percent-annual-chance event were needed to allow hydrodynamic simulations of the levee failure scenarios. The Green River discharge hydrograph for the upstream end of the study reach was developed by scaling up the rising limb portion of the November 2006 flood event to match the 1-percent-annual- chance peak flow quantile (12,800 cfs) and then appending to this the Corps' 1-percent-annual-chance regulated condition target flow (i.e. 9 days at 12,000 cfs). This hydrograph thus maintains the peak discharge characteristics of the steady state hydrology but also reflects the Corps' theoretical regulated discharges from Howard A. Hanson Dam. An argument could be made that this hydrograph is overly conservative since the flows at Auburn in the 47 years since the construction of HAHD have never been sustained at 86 levels as high as the theoretical condition for more than a few days. However, because the authorized operation at HAHD calls for targeting a flow of 12,000 cfs for 9 days in a 1-percent-annual- chance event, and because these discharges may be required for HAHD to be able to safely accommodate the Standard Project Flood, it was determined that incorporation of the extended duration of high flows together with the instantaneous peaks was appropriate for this study. Hydrographs at other downstream inflow points were developed by various estimation techniques. For Mill Creek, Mullen Slough, Midway Creek, and Springbrook Creek flow hydrographs were created using the 1-percent-annual-chance, 9-day discharge for those streams based on past hydrologic modeling efforts by nhc. Inputs to the Green River at other locations (primarily pump stations and tightlines) were estimated based on the pump station or tightline capacity. It should be noted that the cumulative total of these downstream discharge points is approximately 10 percent of the discharge on the Green River near Auburn and thus any errors introduced by the estimation techniques are not expected to have any significant effect on the hydraulic simulations. Hydrologic for Middle Green River analyses were conducted to establish the peak discharge-frequency relationship for the Middle Green River. Hydrologic data for the post Howard A. Hanson Dam period (1961-2007) were analyzed to determine the peak flow data for floodplain mapping. Annual peak flows were derived at three locations along the study reach, at the upstream study limit, at the confluence with Newaukum Creek, and at the confluence with Soos Creek, and flow quantiles at each location were estimated by fitting flood frequency curves to these data. 3.1.9 Revision 9 Sammamish River - Defining appropriate hydrologic data for the Sammamish River was key to developing accurate floodplain analysis. The most significant challenge in developing these data was determining how flow hydrographs from the various tributary basins coincide in time to produce a given peak flow quantile on the Sammamish River. Tributaries to Lake Sammamish comprise a little less than half of the Sammamish River basin area upstream of Lake Washington and outflow from the lake significantly attenuated. Consequently, local runoff and tributary inflows downstream of Lake Sammamish are likely to peak much earlier than lake outflows. The downstream sub-basins, namely (Big) Bear Creek, Little Bear Creek, North Creek, and Swamp Creek, 87 may also peak at different times from each other due to differences in precipitation patterns, land-use conditions (including level of urbanization) and basin storage characteristics. The hydrologic analysis specifically accounted for these differences; otherwise Sammamish River flows could be overestimated and result in an overly conservative floodplain analysis. To address these timing issues, NHC generated long-time series of flows at multiple points along the Sammamish River (including the weir) under current watershed conditions. These time series were generated using a combination of two models; Hydrologic Simulation Program-FORTRAN (HSPF), to stimulate flow inputs from the tributary basins, and HEC-RAS, to route these inflows down the Sammamish River. Frequency analysis was then performed on the simulated peak flows to determine flows for use in the steady state HEC-RAS model for floodplain analysis. The use of continuous hydrologic modeling (HSPF) precluded the need to make judgments regarding the temporal correlation between tributary hydrographs and Sammamish River peak flows. It also allowed NHC to define flood frequency quantiles based on simulation of actual hydrologic response (with the most recently available land use and weir conditions). HSPF Modeling NHC obtained and used existing King County and Snohomish County HSPF models of basins tributary to Lake Sammamish and to the Sammamish River to produce a 60-year time series of flows for each basin (water year 1949 to 2009). The most recent available model for each of the tributary basins was used. King County developed and calibrated HSPF models for all basins in the Sammamish River watershed as part of its Sammamish- Washington Analysis and Modeling Program (SWAMP). These models included Issaquah and Tibbetts Creeks, East Lake Sammamish Tributaries, West Lake Sammamish Tributaries, Bear Creek (including Evans Creek), Little Bear Creek, North Creek, Swamp Creek, and local drainage to the Sammamish River. Land- use conditions represented in these models were from 1995. In more recent work for Snohomish County, NHC has developed and/or updated and calibrated HSPF models for the Swamp, North and Little Bear Creek basins. These models use land-use data current to the time of this flood study analysis (2004 to 2008). The initial simulation periods for the models provided by King County were limited to the period of record of the local precipitation gages used as input (approximately water years 1990 88 through 2003). To produce long-term simulations, precipitation records were extended back to October 1948 by transposing SeaTac precipitation data to each of the local gage locations. A multiplier on SeaTac precipitation was determined for each gage using the ration of local to SeaTac mean annual precipitation from overlapping periods of record. Local gage precipitation records used in the provided Snohomish County models had been extended by similar methods. NHC also extended the simulation period forward to 2009 to capture some recent large storm events. As needed, data gaps were filled by transposing data from nearby gages. Unsteady HEC-RAS Modeling NHC used the HSPF-simulated time series from each tributary as input to an unsteady HEC-RAS model (development of the HEC- RAS model geometry and model calibration is discussed in Section 3.2.9). The unsteady HEC-RAS model was used to route flows through Lake Sammamish and down the Sammamish River. An unsteady RAS model is preferable to HSPF for the river routing for several reasons:  The HEC-RAS model geometry was already being developed for this study, and Lake Sammamish and the Sammamish River are not included in the existing HSPF models.  HEC-RAS can directly model backwater effects and other dynamic conditions on the Sammamish River and at the weir, while HSPF requires static stage-discharge rating curves. Lake Sammamish was modeled as a ―storage area‖ in the unsteady HEC-RAS model with summed inflows from Issaquah, Creek, Tibbetts Creek, and the East and West Lake Sammamish tributaries, as well as precipitation gains and evaporation losses on the lake surface. Precipitation and evaporation fluxes to the lake surface were generated from data sets used in the HSPF modeling assuming a constant lake surface area. HSPFsimulated flows from Bear, Little Bear, North and Swamp Creeks were modeled as lateral inflows to the Sammamish River. Other local runoff to the Sammamish River was modeled as uniform lateral inflows in five separate reaches: Lake Sammamish to Bear Creek, Bear Creek to Little Bear Creek, Little Bear Creek to North Creek, North Creek to Swamp Creek, and Swamp Creek to the mouth. For the 60-year simulation, the weir was assumed to always be in place and the HSPF land uses unchanging (e.g. not reverting back to 1950s land use) to determine flow quantiles for the watershed conditions that exist today. 89 Flow Frequency Analysis NHC performed flow frequency analysis on the 60 years of simulated Sammamish River flows to identify 10-, 2-, 1- and 0.2- percent-annual-chance exceedance flow quantiles at key locations along the Sammamish River between Lake Sammamish and Lake Washington. Flow quantiles were determined at the upstream end of the Sammamish River, at major tributary confluences (i.e, Bear, Little Bear, North, and Swamp Creeks), near Northeast 116th and Northeast 145th Streets, and at the confluence with Lake Washington, the computed peak flows were then used as input to steady HEC-RAS simulations to evaluate the 10-, 2-, 1- and 0.2- percent-annual-chance exceedance water surface profiles and define the regulatory floodway. White River – Hydrologic analyses were conducted to establish the peak discharge-frequency relationship for the White River. Hydrologic data for the post Mud Mountain Dam period (1946- 2007) were analyzed to determine the peak flow quantiles for use in the floodplain mapping. Annual peak flow quantiles were estimated at three locations along the studied reach: approximately 1,275 feet downstream of State Highway 410; at the confluence of Red Creek; and at the confluence of Boise Creek. Flow quantiles approximately 1,275 feet downstream of State Highway 410 were estimated using frequency analysis of the adjusted dam discharge record as described by NHC. Quantiles for the intervening locations were estimated based on the proportionate share of the local basin tributary to the White River between Mud Mountain Dam and the analysis point. Peak discharge-drainage area relationships for the streams studied by detailed methods are shown in Table 2. Table 2- Summary of Discharges Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance BEAR CREEK At State Route 202 49.8 1,060 1,365 1,535 2,000 Above Evans Creek confluence 33.6 774 996 1,121 1,460 At River Mile 2.4 32.2 742 956 1,075 1,400 At N.E. 95th Street 30.1 710 915 1,028 1,340 At River Mile 3.5 29.3 689 887 998 1,300 Table 2 – Summary of Discharges (Continued) 90 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance BEAR CREEK (Continued) Above Cottage Lake Creek confluence 14.7 320 460 520 690 Above Seidal Creek confluence 11.6 260 380 430 570 15 feet downstream of N.E. 145th Street 11.2 250 360 410 550 Above Struve Creek confluence 8.7 200 290 330 450 Above tributary confluence 3,200 feet upstream of N.E. 148th Street 8.0 190 270 310 410 1,500 feet downstream of Woodinville-Duvall Road 7.4 180 250 290 390 At Woodinville-Duvall Road 5.8 140 200 230 310 BIG SOOS CREEK At USGS gage 12-112600 66.7 1,130 1,440 1,550 1,790 Below Covington Creek confluence 49.4 870 1,110 1,190 1,380 Above Covington Creek confluence 31.2 580 740 800 920 Above Jenkins Creek confluence 13.5 270 350 390 450 Above Little Soos Creek confluence 9.3 200 250 280 320 At S.E. 244th Street 7.1 150 200 220 260 At S.E. 208th Street 4.5 100 130 150 170 BLACK RIVER Above Green River confluence 24.8 4001 4001 4001 4001 At P1 pump station inlet 24.8 650 1,040 1,230 1,730 CEDAR RIVER At USGS gage 12-119000 184 5,940 9,860 12,000 18,400 At 149th Avenue SE --2 5,750 9,550 11,650 17,950 At Cedar Grove Road --2 5,550 9,350 11,400 17,600 At Renton Maple Valley Road --2 5,450 9,200 11,250 17,350 At State Route 18 --2 5,250 8,850 10,900 16,900 At Landsburg SE 121 4,880 8,340 10,300 16,100 COAL CREEK At mouth 7.31 228 306 340 420 At Interstate Highway 405 6.76 213 287 320 396 1400 cfs discharge from pump station coincides with peak flows in Green River 2Data Not Available Table 2 – Summary of Discharges (Continued) 91 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance COAL CREEK TRIBUTARY (NEWPORT CREEK) At mouth 0.31 14 21 25 35 COTTAGE LAKE CREEK At mouth 1 288 386 428 527 DES MOINES CREEK Below Marine View Drive South 5.8 400 600 702 945 EAST BRANCH OF WEST TRIBUTARY (KELSEY CREEK) At mouth 0.92 37 56 64 86 EAST FORK ISSAQUAH CREEK At mouth 9.5 560 900 1,050 1,980 EVANS CREEK Above Bear Creek confluence (including Bear Creek split-flow return) --1 314 476 581 905 At River Mile 0.4 15.3 280 360 400 496 Near Redmond, at River Mile 0.8 13.0 280 360 400 496 FORBES CREEK At mouth 3.7 150 180 220 260 GARDINER CREEK At Northwest 8th Street 1.3 150 --1 300 --1 GILMAN BOULEVARD OVERFLOW At divergence from Issaquah Creek --1 0.0 370 610 1,250 GREEN RIVER RM 44.3-40.4 Reach 1 (Upstream of Newaukum Creek) --1 11,060 11,890 12,070 12,290 RM 40.4-33.3 Reach 2 (Newaukum Creek to Soos Creek) --1 11,250 12,080 12,250 12,460 RM 33.3-23.7 Reach 3 (Soos Creek to Mill Creek --1 11,230 12,420 12,810 13,460 1Data Not Available Table 2 – Summary of Discharges (Continued) 92 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance GREEN RIVER (Continued) Reach 4 (Mill Creek to Black River) Varies by Subreach RM 23.7-21.5 Reach 4a (Downstream of Mill Creek Confluence --1 11,580 12,500 12,530 12,610 RM 21.5-19.5 Reach 4b (Downstream of Mullen Slough --1 11,700 12,650 12,690 12,800 RM 19.5-16.5 Reach 4c (Downstream of Midway Creek Confluence) --1 11,740 12,700 12,750 12,870 RM 16.5-11.0 Reach 4d (Downstream of Tightline at RM 16.5) --1 11,930 12,890 12,930 13,050 RM 11.0-0.0 Reach 5 (Black River to Mouth --1 12,410 13,370 13,410 13,530 Above Howard A. Hanson Dam 215.0 20,050 29,250 33,500 49,000 HOLDER CREEK Above confluence with Carey Creek 7.5 420 660 800 1,150 ISSAQUAH CREEK At mouth 55.6 2,890 3,700 3,960 4,490 City Limit to Gage at 12121600 54.3 2,890 3,400 3,560 3,940 Through Gilman Bridge 49.4 2,570 3,320 3,550 4,000 Upstream of Gilman Overflow 49.3 2,570 3,690 4,160 5,250 Downstream of East Fork 49.2 2,560 3,670 4,140 5,230 Upstream of East Fork 39.7 2,080 2,980 3,360 4,230 KELSEY CREEK At mouth 10.10 301 398 439 536 At 140th Avenue N.E. 6.69 211 285 317 393 At Lake Hills Boulevard 2.25 84 121 138 179 LITTLE BEAR CREEK Above Sammamish River confluence 15.6 320 450 500 570 Above SR-202 15.5 340 490 570 750 At Highway 522 14.7 330 480 550 740 At N.E. 205th Street 13.6 310 450 520 700 LONGFELLOW CREEK At S.W. Brandon Street 2.7 170 310 380 520 1Data Not Available Table 2 – Summary of Discharges (Continued) 93 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance LONGFELLOW CREEK (Continued) At 26th Street S.W. 2.5 160 290 350 480 At S.W. Juneau Street 2.2 140 250 310 420 At 25th Avenue S.W. 2.1 130 240 290 400 At S.W. Willow Street 2.0 120 230 280 380 At S.W. Myrtle Street 1.4 84 150 180 250 At S.W. Webster Street (Detention basin outflow) 1.2 76 130 150 220 At S.W. Holden Street 1.1 74 120 140 200 LYON CREEK At mouth 3.67 147 177 188 214 MALONEY CREEK At Skykomish 3.8 750 980 1,130 1,380 MAY CREEK At USGS gage 12-119600 12.7 480 800 870 1,020 At Coal Creek Parkway 8.9 350 580 640 750 At 146th Avenue S.E. 7.7 310 520 560 660 At 148th Avenue S.E. 6.9 280 470 510 600 At 146th Avenue S.E. 4.8 200 340 370 440 At S.E. Renton-Issaquah Road 2.9 130 220 240 280 At S.E. May Valley Road 1.2 59 100 110 130 At S.E. 109th Place 0.9 46 78 87 100 MAY CREEK TRIBUTARY Above confluence with May Creek 1.5 72 120 140 160 McALEER CREEK At mouth 7.80 215 278 304 364 MERCER CREEK (INCLUDING BOTH MAIN AND RIGHT CHANNEL) At mouth 17.79 490 628 686 819 At confluence with Kelsey and Richards Creeks 13.75 393 510 560 675 MEYDENBAUER CREEK At mouth 1.33 133 150 160 177 At S.E. 6th Street 0.12 --1 --1 41 --1 1Data Not Available Table 2 – Summary of Discharges (Continued) 94 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance MIDDLE FORK LOWER OVERFLOW At divergence from Middle Fork --1 200 1,600 2,300 4,200 Downstream of divergence of Middle Overflow --1 100 1,100 1,400 2,600 MIDDLE FORK MIDDLE OVERFLOW --1 100 500 900 1,600 MIDDLE FORK SNOQUALMIE RIVER At mouth 171.0 26,900 34,800 38,600 46,900 At Mt. Si Bridge 169.0 28,000 38,300 43,800 55,800 MIDDLE FORK UPPER NORTH OVERFLOW --1 500 1,500 2,150 3,700 MIDDLE FORK UPPER SOUTH OVERFLOW At divergence from Middle Fork --1 1,000 3,000 4,300 7,400 Downstream of divergence of Upper North Overflow --1 500 1,500 2,150 3,700 MILL CREEK (AUBURN) Above confluence with Green River 12.8 250 360 410 510 At 277th Street 11.7 230/220 330/320 370/360 480/470 At 37th Street, N.W. 9.8 200/190 290/280 340/320 500/420 At 29th Street, N. W. 8.9 180 270 310 450 At Valley Freeway (SR- 167) 8.0 180/170 270/250 310/280 500/400 At 15th Street, N.W. 7.6 190/170 300/250 370/290 570/480 At Main Street 6.2 160 250 310 490 At Peasley Canyon Way 5.7 140 230 290 450 At 15th Street, N.W. 0.7 --1 --1 40 --1 MILL CREEK (KENT) At confluence with Springbrook Creek 9.2 380 --1 650 --1 At Highway 167 culvert entrance 3.1 110 125 130 140 At Bowen-Scarff culvert outlet 2.9 110 115 120 130 Downstream of Springbrook Creek Overflow 2.7 85 90 100 110 At James Street 2.6 70 110 140 180 1Data Not Available Table 2 – Summary of Discharges (Continued) 95 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance MILLER CREEK (Continued) At mouth 8.1 383 575 670 1050 At sewage treatment plant --1 278 415 479 785 At confluence with Lake Burien Tributary --1 239 364 429 --1 Below 1st Avenue --1 159 245 293 475 Below State Highway 509 --1 151 235 275 450 At confluence with Lake Lora Tributary --1 109 176 211 --1 At Lake Reba outflow --1 90 150 177 310 NORTH BRANCH MERCER CREEK (NORTH VALLEY CREEK) At mouth 3.10 111 157 177 227 At N.E. 40th Street 1.12 46 69 79 106 NORTH CREEK At mouth 30 958 1,290 1,440 1,810 Near Bothell (USGS gage No. 12-1260) 24.6 454 581 634 757 NORTH FORK ISSAQUAH CREEK At mouth 4.8 176 269 315 445 At mouth (including overtopping from Issaquah Creek) 4.8 176 489 835 1,995 NORTH FORK MEYDENBAUER CREEK At 102nd Avenue S.E. 1.03 94 105 113 128 NORTH FORK SNOQUALMIE RIVER At mouth 103.0 18,600 24,600 27,200 32,800 At North Bend gage 96.0 14,700 19,700 21,700 26,200 At Snoqualmie 64.0 12,300 16,300 18,000 21,700 NORTH FORK THORNTON CREEK Above South Fork Thornton Creek confluence 7.2 160 270 320 470 Below tributary confluence downstream of N.E. 115th Street 6.8 140 230 280 410 1Data Not Available Table 2 – Summary of Discharges (Continued) 96 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance NORTH FORK THORNTON CREEK (Continued) At N.E. 115th Street and 35th Avenue N.E. 5.6 90 150 180 270 At N.E. 125th Street 5.2 67 120 150 240 At 15th Avenue N.E. 4.2 42 82 110 170 At Interstate Highway 5 3.7 32 65 84 140 PATTERSON CREEK Snoqualmie River to Tributary 0377 --1 560 740 820 990 Tributary 0377 to Canyon Creek --1 410 550 610 750 Canyon Creek to RM 4.56 --1 300 410 450 550 RM 4.56 to RM 5.92 --1 270 360 390 470 RM 5.92 to RM 7.77 --1 220 290 320 380 RM 7.77 to Redmond-Fall City Road --1 160 220 240 300 Upstream of Redmond-Fall City Road --1 90 130 150 180 RAGING RIVER At mouth 32.9 4,031 6,286 7,413 10,465 At USGS gage 12-145500 30.6 3,790 5,910 6,970 9,840 Above Interstate Highway 90 25.7 3,268 5,095 6,009 8,483 Above Lake Creek confluence 20.2 2,652 4,135 4,877 6,885 Above Deep Creek confluence 13.3 1,851 2,887 3,404 4,806 RICHARDS CREEK At mouth 3.63 122 170 191 241 At Interstate Highway 90 1.11 44 65 75 99 At S.E. Newport Way 0.80 33 50 58 78 RICHARDS CREEK EAST TRIBUTARY Approximately 325 feet upstream of S.E. 26th Street2 0.06 4 36 47 81 RICHARDS CREEK WEST TRIBUTARY At mouth 0.91 37 55 64 85 1Data Not Available 2Includes overflow from Richards Creek for 2-, 1-, and 0.2-percent-annual-chance discharge Table 2 – Summary of Discharges (Continued) 97 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance ROLLING HILLS CREEK At Highway 405 culvert entrance near Highway 167 1.2 721 861 911 --2 Below east storm drain confluence 600 feet upstream of Highway 405 1.2 77 110 130 --2 SAMMAMISH RIVER At confluence with Lake Washington --2 3,980 4,930 5,300 6,130 Just downstream of the confluence of Bear Creek --2 1,980 2,420 2,590 2,970 SNOQUALMIE RIVER At Duvall --2 53,400 75,800 84,600 99,700 At Carnation 603.0 58,200 82,400 91,800 113,300 Near Snoqualmie 375.0 51,700 71,000 79,100 95,200 SOUTH FORK SKYKOMISH RIVER At Index gage 355.0 44,300 65,200 74,700 98,500 At Baring 336.0 42,300 62,200 71,300 94,000 Just upstream of Miller Creek 245.0 32,200 47,400 54,300 71,600 Just upstream of Beckler River 139.0 12,600 19,400 22,800 31,700 SOUTH FORK SNOQUALMIE RIVER At mouth 86.8 10,100 16,500 20,200 28,600 At North Bend gage 81.7 9,000 13,000 15,000 19,700 At Edgewick gage 65.9 8,900 12,900 14,900 19,500 SOUTH FORK THORNTON CREEK At 35th Avenue N.E. and N.E. 105th Street 3.8 150 230 270 380 At 30th Avenue N.E. 3.6 140 210 250 350 At Lake City Way 3.2 120 180 210 300 At N.E. 107th Street 2.1 72 110 130 180 At N.E. 105th Street and 8th Avenue N.E. 1.4 50 75 89 120 SPRINGBROOK CREEK Upstream of confluence with Black River 21.9 5903 930 1,1003 1,550 1Downstream decrease in discharge results from routing effects of hydraulic structures 2Data Not Available 3Decrease in discharges due to P1 pumping plant pumping 300 cfs into Green River flood stages Table 2 – Summary of Discharges (Continued) 98 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance SPRINGBROOK CREEK (Continued) Downstream of confluence with Mill Creek (River Mile 3.03) 16.1 6801 --2 1,055 --2 SWAMP CREEK At USGS gage 12-127100 23.1 600 810 910 1,160 At tributary confluence downstream of 73rd Avenue N.E. 21.9 570 770 870 1,110 At N.E. 205th Street 20.9 550 740 830 1,060 THORNTON CREEK Above mouth at Lake Washington 12.1 190 290 390 670 At N.E. 93rd Avenue 11.7 150 230 330 590 At 45th Avenue N.E. 11.5 140 210 310 560 At N.E. 105th Street 11.1 110 170 260 490 At diversion weir to downstream channel 11.0 100 160 250 480 At diversion to Lake Washington --2 210 330 340 350 Below confluence of North and South Fork Thornton Creek 10.9 310 490 590 830 TIBBETTS CREEK At mouth 3.9 220 355 425 600 At confluence with West Fork Tibbetts Creek 2.8 183 254 286 367 At approximately 600 feet upstream of Southwest 83rd Place 1.9 129 180 203 261 TOLT RIVER At mouth 97.0 13,900 19,500 22,000 27,800 At USGS Gage 12148500 (near Carnation) 81.4 11,900 16,700 18,800 23,800 UNNAMED DRAINAGEWAY In the central business district in the city of Kirkland 1.5 --2 --2 --2 --2 VASA CREEK At mouth 1.37 55 81 93 123 At cross section R 0.53 24 38 44 60 1400 cfs discharge from pump station coincides with peak flows in Green River 2Data Not Available Table 2 – Summary of Discharges (Continued) 99 Flooding Source and Location Peak Discharges (cfs) Drainage Area (square miles) 10-Percent- Annual- Chance 2-Percent- Annual- Chance 1-Percent- Annual- Chance 0.2-Percent- Annual- Chance WALKER CREEK Above confluence with Miller Creek 1.5 281 400 461 605 WEST FORK ISSAQUAH CREEK Above Issaquah Creek confluence 4.9 290 460 550 790 2,900 feet upstream of 229th Drive S.E. 4.7 270 440 530 770 Above tributary confluence near 208th Avenue S.E. 1.5 100 160 200 280 WEST TRIBUTARY KELSEY CREEK At mouth 1.75 64 92 104 135 At upstream confluence of East Branch 0.34 16 25 29 41 WHITE RIVER At Pacific and Auburn 454 14,000 15,300 15,500 19,000 YARROW CREEK At mouth 2.2 --1 --1 126 --1 At unnamed drainageway in Central Business District 1.5 --1 --1 339 --1 At N.E. 40th Street 0.73 29 44 41 68 1Data Not Available The USACE regulates the water level of Lake Washington at the Hiram M. Chittenden Locks on the Lake Washington Ship Canal. The lake level is drawn down during the winter months and is typically regulated at elevation 16.8 NAVD for that period. In the summer months, the lake level is raised to an elevation of 18.6 feet NAVD. That elevation exceeds the normal depth water-surface elevation determined at the mouth of the Cedar River for the 10-, 2-, and 1-percent- annual-chance recurrence interval flows. Therefore, the flood profiles for the Cedar River includes the backwater impact from Lake Washington until the profile that was started at normal depth exceeds the 15.0-foot elevation for the 1-percent-annual-chance recurrence interval event at the first cross section, with lake backwater shown for the lesser recurrence intervals. Elevations on Lake Sammamish for the various frequency floods are controlled by the USACE Lake Sammamish outlet project built in 1966. 100 This project consists of a low weir designed to maintain the lake elevation at 32.6 feet for the 10-percent-annual-chance flood. The elevations for the 2-, 1-, and 0.2-percent-annual-chance floods were computed by routing techniques through the lake. Elevations for floods for the selected recurrence intervals are also presented in Table 3. Table 3 – Summary of Elevations Elevation in Feet (NAVD 88) Flooding Source and Location 10-percent-annual- chance 2-percent-annual- chance 1-percent-annual- chance 0.2-percent-annual- chance Lake Sammamish 34.5 35.8 36.2 37.3 Phantom Lake * * 263.8 * *Data Not Available 3.2 Hydraulic Analyses Analyses of the hydraulic characteristics of flooding from the sources studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. Flood elevations shown on the FIRM are primarily intended for flood insurance rating purposes. For construction and/or floodplain management purposes, users are cautioned to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross section data for the backwater analysis for Miller Creek, Walker Creek, and a portion of Des Moines Creek were taken from topographic maps with 2 foot contour intervals (Reference 44). Cross section data for North Creek and White River (left bank overflow) were taken from aerial photographs (References 45 and 46). Cross section data for the Snoqualmie River and North, Middle, and South Forks Snoqualmie River were obtained from field surveys and aerial photographs (References 1, 47, 48, and 49). The cross section data for the backwater analyses for the remaining streams studied by detailed methods were obtained by field survey. Cross section data for the overbank areas of Green River, Tibbetts Creek, Issaquah Creek, and East Fork Issaquah Creek were based on topographic base maps (References 50 and 51). The flooding potential, in the form of ponding, for the unnamed drainageway in the central business district in Kirkland, is directly related 101 to the capacity of the existing stormwater drainage system. The capacity of this system was determined and removed from the runoff produced by the design storm. The volume of the remaining excess runoff was then compared to a storage-elevation curve developed for the central business district. This comparison yielded the maximum expected elevation for the predicted 1-percent-annual-chance event. Based on a Letter of Map Revision (LOMR) dated January 30, 1989, and due to improvements done in that area, the drainageway was moved to reflect the LOMR. Water-surface elevations of floods of the selected recurrence intervals on Mercer Creek, Right Channel Mercer Creek, Meydenbauer Creek, North Fork Meydenbauer Creek, Coal Creek, Vasa Creek, Richards Creek East Tributary, Richards Creek West Tributary, Kelsey Creek, West Tributary Kelsey Creek, East Branch of West Tributary Kelsey Creek, North Branch Mercer Creek, and Yarrow Creek were computed using the USGS E-431 step-backwater computer model (Reference 52). Water-surface elevations of floods of the selected recurrence intervals on Lyon Creek and McAleer Creek downstream of Northeast 178th Street were computed by hand calculations. McAleer Creek passes through 10 significant hydraulic structures, one private culvert, and numerous private bridges. Lyon Creek passes through 12 significant hydraulic structures. Each of these structures was rated for hydraulic capacity by applying standard hydraulic calculations and hydraulic nomographs (References 53, 54, 55, and 56). The water-surface elevations for a portion of the upper Green River Valley were computed using the USACE G3722110 Water-Surface Profiles computer program (Reference 57). The water-surface elevations of floods of the selected recurrence intervals on the remaining streams studied by detailed methods were computed using the USACE HEC-2 step-backwater computer program (Reference 58). The starting water-surface elevations for the Snoqualmie River and North, South, and Middle Forks Snoqualmie River, Sammamish River, Tibbetts Creek, and Green River were developed using the slope-area method or were developed from hydraulic rating data. For the most downstream portion of the Green River, the starting water-surface elevation was based on previous studies. The starting water-surface elevation of 6.6 feet, which lies below the highest estimated tide and above the mean high water elevation, was calculated by the USACE with the coordination of FEMA Region X. 102 Starting water-surface elevations for Raging, Cedar, and South Fork Skykomish River, and Big Soos, Swamp, Issaquah, West Fork Issaquah, Thornton, Longfellow, Forbes, Yarrow and Maloney Creek were determined using normal depth from slope-area methods. Starting water-surface elevations for Rolling Hills Creek and May Creek were determined to be critical depth. Starting water-surface elevations for May Creek Tributary were the corresponding recurrence interval event water-surface elevations in the main stem at the point of confluence with the tributary. The starting water-surface elevations for Bear and Evans Creeks are coincident with the elevations at the confluences of the Sammamish River and Bear Creek, respectively. Starting water-surface elevations for the White River were taken from the USACE computer printout and flood profiles prepared in 1974 (Reference 40). The starting water-surface elevation for Lyon Creek and McAleer Creek was the maximum control elevation of Lake Washington, which is 15 feet. The starting water-surface elevation for North Creek at its mouth was the 10-percent-annual-chance flood elevation from the Sammamish River. Starting water-surface elevations for Little Bear Creek were based on a coincident 25-year recurrence interval Sammamish River flood stage, as was estimated to occur for the January 1986 flooding event. The starting water-surface elevation for Mill Creek (Auburn) was based on computed Green River backwater elevations at the Mill Creek outlet using mean monthly Green River flow data for December and January. The starting water-surface elevation on Mill Creek (Kent) was obtained from the Springbrook Creek flood profile. Starting water-surface elevations for the flood profiles for Miller Creek and Walker Creek were taken from the hydraulic study of Puget Sound. Starting elevations for the flood profiles for Des Moines Creek were taken using the 10-percent-annual-chance elevation computed for Puget Sound. For the coastal area studied by detailed methods, the effects of high tidal levels and wave runup were combined to determine the maximum flood elevations above the NAVD 1988 datum. Wave prediction and wave runup calculations were performed by methods prescribed in the USACE Shore Protection Manual (Reference 59). 103 Starting water-surface elevations for Mercer, Right Channel Mercer, Meydenbauer, North Fork Meydenbauer, Coal, Vasa, Richards, East Tributary Richards, West Tributary Richards, Kelsey, West Tributary Kelsey, East Branch of West Tributary Kelsey, and North Branch Mercer Creeks were computed form: 1. Frequency analysis of lake elevations 2. Profile conveyance of downstream cross sections 3. Culvert ratings where an approach section was the section farthest downstream The starting water-surface elevations for the Black River, North and East Forks Issaquah Creek, and North and South Forks Thornton Creek are coincident with the elevations at the confluences of the Green River, Issaquah Creek, and Thornton Creek, respectively. For the Green River, analyses were performed in accordance with FEMA’s levee policy. In accordance with those guidelines, two backwater profiles were computed for the reach under study, one for flows confined to the levee system, and a second for the condition of complete levee systems assumed removed for analysis, where levee system freeboard is less than minimum FEMA standards. The general freeboard standard of 3 feet for consideration of levee flood protection was lowered by FEMA for the Green River to 2 feet based on USACE review and recommendations, at the request of King County (Reference 60). Based on the computed with levees water-surface profiles and surveyed cross section and levee profile data, a total of approximately 5.7 river miles of levees were identified as having less than 2 feet of freeboard at some locations along a particular levee system. On Little Bear Creek, high water marks for the January 1986 event were used to calculate flows through culverts and to reduce flows at overbank breakout points, from upstream of the SR 202 culvert, downstream to the Sammamish River confluence. The HEC-2 step-backwater model was calibrated to these conditions. A range of flows were input to the model to develop rating curves for the structures and overflow weirs. The recurrence flows, derived from the hydrologic analyses, were modified to reflect the overflow conditions from review of the rating curves. Sheetflow and ponding caused by the channel overflow was approximated from photographs, topographic maps, high water marks, and local accounts of flooding extent and depths. The maximum water-surface elevation of the P1 storage pond in Renton was determined by routing the hydrograph through the storage pond and pumping station by using the storage-elevation relationship for the pond 104 and the pumping station’s firm capacity of 875 cfs as the maximum discharge. The 10-percent-annual-chance water-surface profile for Springbrook Creek was started at normal depth because normal depth was greater than 3.5 feet NGVD, which is the maximum water-surface elevation of the P1 storage pond under standard operating procedures. The peak 10-percent-annual-chance flow into the storage pond is less than the maximum pumping rate and, therefore, no rise in the water-surface elevation of the storage pond should occur during the 10-percent-annual- chance event. Two conditions were considered for each of the 2-, and 1- percent-annual-chance events. The first consisted of modeling the effects on the Springbrook Creek study reach of the computed maximum water- surface elevation that may be reached in the storage pond (the starting water-surface elevation) coincident with the flow that would be discharged from Springbrook Creek at that time step in the inflow runoff hydrograph. The second condition of analysis consisted of modeling the effects of Springbrook Creek peak inflows for the recurrence interval event under consideration, with a starting water-surface elevation of the higher of normal depth, or the coincident elevation of the storage pond at the time of the peak inflow. For each recurrence interval, the higher water-surface elevation resulting from each of those analysis conditions at the study reach cross sections was used for final flood profile determination. Areas of coastline subject to wave attack are referred to as coastal high hazard zones. Factors considered in determining wave runup included length of fetch, sustained wind velocities, coastal water depths, land slopes, and other physical features of the coastline that could appreciably affect wave propagation. Much of the coastline along Des Moines is protected by a breakwater that extends north and south along the coast to protect the Des Moines Marina. The area west of this breakwater and the unprotected area north and south of the breakwater have been designated coastal high hazard zones. The unprotected sections of the coastline are subject to wave attack generated by high winds from a southwest direction across Puget Sound. The remaining coastal areas inland from the breaking waves, subject only to wave runup, and areas sheltered by the breakwater are not exposed to severe wave attack and have not been designated as part of a coastal high hazard zone. Channel and overbank roughness factors (Manning’s ―n‖) used in the hydraulic computations were chosen by engineering judgment and were based on field observations of the stream and floodplain areas, and hydraulic calibration of flood profiles to available high water mark data. The range of channel and overbank ―n‖ values for the various flooding sources are listed in Table 4. Flood profiles were computed an accuracy of approximately 1 foot for floods of the selected recurrence intervals and are shown in Exhibit 1. The 105 degree of accuracy of the water-surface profiles is limited to 1 foot by the location and accuracy of the cross sections, the extent of the various energy losses of the system, and the general limitations of backwater calculations. The accuracy of 1 foot is consistent with the accuracy of predicted peak discharges and the knowledge that unpredictable events during actual floods will likely cause deviations from the predicted profile. Locations of selected cross sections used in the hydraulic analyses are shown on the Flood Profiles (Exhibit 1). For stream segments for which a floodway was computed (see Section 4.2), selected cross section locations are also shown on the Flood Insurance Rate Maps (Exhibit 2). For streams studied by approximate methods, the 1-percent-annual-chance floodplains were approximated by field inspections and observations and by normal depth calculation using estimated 1-percent-annual-chance recurrence interval floodflows and approximate cross sections taken from field investigations or from topographic maps, where available. Computed depth from minimum channel elevation and average floodflow velocity are shown on the maps. The hydraulic analyses for this study were based on unobstructed flow. The flood elevations shown on the profiles are thus considered valid only if hydraulic structures remain unobstructed, operated properly, and do not fail. 3.2.1 Revision 1 Miller Creek - Analyses of the hydraulic characteristics of Miller Creek were carried out to provide estimates of flood elevations for the 10-, 2-, 1-, and 0.2-percent-annual-chance events. Water- surface elevations were computed using the September 1990 release of the USACE HEC-2 backwater computer program (Reference 97). Data required to develop the HEC-2 model include channel and floodplain geometry, roughness coefficients, and starting water-surface elevations. Cross-section data for the backwater analyses were obtained from field surveys performed between November 1990 and January 1991. A total of 32 sections were surveyed. All significant bridges, culverts, and weirs were surveyed to obtain elevation data and structural geometry. A total of six bridges, eight culverts, and 11 weirs were surveyed. In the HEC-2 program, the special bridge routine was used for bridges with piers and for those where pressure flow occurred. The normal bridge routine was used for bridges without piers and for low-flow conditions where the water surface was below the low-chord elevation of the bridge. Local residents have built a 106 number of small, wooden foot bridges across the creek. These were not included in the model. Water-surface elevations at each culvert were also computed using the HEC-2 model, which incorporated the capability to simulate culvert hydraulics using Federal Highway Administration culvert procedures. For weir flow, water-surface elevations at each weir were computed using the HEC-2 model. The geometry of each weir was defined in the model, and water-surface elevations were computed using standard step-backwater analyses. Channel roughness (Manning’s ―n‖) values used in hydraulic computations were determined using engineering judgment, reference to classical publications (References 98 and 99), and calibration to observed conditions. Flood profiles were matched with high-water marks and discharge data collected during January and February 1991 events. Selected channel ―n‖ values range from 0.040 to 0.057, and overbank values range from 0.070 to 0.110. The starting water-surface elevation was calculated using the slope-area method, based upon an assumed water-surface slope of 0.003. Tub Lake Tributary flows from a depression area south of Beverly Park along Des Moines Way heading south. It then empties into the Lake Reba Detention Pond through a culvert underneath State Highway 518. Because this is a minor tributary to the mainstem of Miller Creek, approximate methods were used to assess the flood hydraulics. This tributary consists of approximately 1,300 feet of open channel and 250 feet of piped segments. From its confluence with Miller Creek, the tributary begins as an open channel. Approximately 900 feet upstream, a 200-foot long, 18-inch- diameter steel pipe carries flow under a little league baseball field. Upstream, 400 feet of open channel carry flow from a 240-inch- diameter corrugated metal pipe (CMP) culvert that conveys flow under South 144th Street. The Tub Lake marsh area begins north of South 144th Street. Both open channel reaches are represented in the HEC-2 model by a trapezoidal cross section that has a 4-foot depth, a 4-foot bottom width, and 2H:1V side slopes. Channel and floodplain geometry used in the model were estimated from available topographic mapping and data collected during a site reconnaissance. Channel roughness coefficients were assumed to be 0.065 for open channel, 0.070 for overbanks, 0.015 for the steel culvert, and 0.024 for the CMP culvert. 107 The hydraulic analyses for this study were based on unobstructed flow. The flood elevations shown on the profiles are thus considered valid only if hydraulic structures remain unobstructed, operate properly, and do not fail. Elevation Reference Marks (ERMs) were established at eight sites along the stream. Floodplain boundaries were delineated in the detailed study reach of Miller Creek and its tributary using topographic maps at a scale of 1:2,400, with a 5-foot contour intervals, provided by the King County Department of Public Works and the City of Seattle Engineering Department. The floodways developed in this study were computed with the HEC-2 model, generally with the assumption of equal-conveyance reduction from each side of the floodplain. Floodway widths were computed at each cross section. Between sections, the floodway boundaries were interpolated. The results of the floodway study are tabulated for each cross section in Table 6, ―Floodway Data.‖ No floodway was computed for the Tub Lake Tributary. The information for this restudy of Miller Creek supersedes the data presented in the previous Flood Insurance Study for King County, dated September 29, 1989 (Reference 94). The discharges used in this study of Miller Creek were revised to account for the effects of urbanization and operations of the newly constructed Lake Reba Detention Pond. This restudy was completed in September 1991. 3.2.2 Revision 2 Snoqualmie River - Nhc compared the two hydraulic studies performed by Hosey & Associates for Puget Power and measured high-water marks with the profiles published by FEMA for the Snoqualmie River in the vicinity of the City of Snoqualmie. The more recent of these two studies incorporated updated topographic information and was calibrated using information from recent storms. When the profiles produced by these studies matched FEMA’s profile, it was determined that a restudy of the area was not warranted at that time. However, upon comparison between the base (1-percent-annual-chance) flood elevation (BFE) placements shown on Flood Insurance Rate Map Panels 53033C0737 K, 53033C0739 K, 53033C0741 K, and 53033C0743 K and those shown on the published profile, it was determined that the BFE placements shown on the above- mentioned Flood Insurance Rate Maps were incorrect. Therefore, 108 the BFE placements shown on the above-mentioned Flood Insurance Rate Map panels were revised along the Snoqualmie River from approximately 1,530 feet upstream of State Highway 202 to its confluence with the South Fork Snoqualmie River to match those shown on the published profiles for that reach. 3.2.3 Revision 3 Raging River - The hydraulic analysis for the revised study of the downstream reach was performed using the USACE HEC-2 backwater computer program (Reference 97). Data for the cross sections, including overbank areas, were taken from field surveys performed in April 1993. A total of 52 sections were surveyed, including seven bridges. There are additional bridges along the Raging River that were not modeled because they do not affect the water-surface elevations of the river. Channel and overbank roughness coefficients (Manning’s ―n‖) used in the computer program for the downstream reach were estimated from experience and field observations. Values range from 0.035 to 0.055 in the channel and from 0.050 to 0.090 in the overbank areas. The starting water-surface elevation was obtained by the slope-area method based on an estimated slope of the energy-grade line. Downstream of 328th Way to the confluence with the Snoqualmie River, the Raging River is confined between levees. However, these levees do not meet FEMA freeboard requirements. Therefore, the water-surface profiles for the area affected by the levees were computed as follows: 1. For the area between the levees, the profiles were determined considering that both levees would remain in place. 2. For the right overbank (looking downstream), the profiles and floodplain boundary were determined without considering the effects of the right levee. 3. For the left overbank, the profiles and floodplain boundary were determined without considering the effects of the left levee. For the upstream reach, the revised discharge values were used to complete a revised hydraulic analysis using HEC-2 and the cross- section information and Manning’s ―n‖ values from the previous 109 Flood Insurance Study. The water-surface elevations increased by a maximum of 4.7 feet approximately 0.6 mile upstream of I-90 and the floodplain width increased by a maximum of 120 feet approximately 1.3 miles upstream of I-90. The 1-, and 0.2-percent-annual-chance floodplain boundaries for both the upstream and downstream reaches were delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps at a scale of 1:2,400, with a contour interval of 2 feet (Reference 100) for the downstream reach. The topographic work maps (Reference 65) from the previous Flood Insurance Study were used to delineate the floodplain boundaries between cross sections for the upstream reach. In cases where the lines are collinear, only the 1-percent-annual-chance flood boundary has been shown. The floodway determined for the Raging River was computed based on equal conveyance reduction from each side of the floodplain, and in the floodplain area downstream of 328th Way, the floodway was determined without consideration of the levees. Floodway widths were computed at each cross section. Between sections, the floodway boundaries were interpolated. In cases where the floodway line is collinear with the 1-percent-annual- chance floodplain line, only the floodway line has been shown. Locations of selected cross section used in the hydraulic analyses are shown on the Flood Profiles (Exhibit 1). The hydraulic analyses for this study were based on unobstructed flow. The flood elevations shown on the profiles are thus considered valid only if hydraulic structures remain unobstructed, operate properly, and do not fail. 3.2.4 Revision 4 North Fork Issaquah Creek - Updated estimates of Issaquah Creek 1-percent-annual-chance elevations affecting the North Fork channel have been reported by the City of Issaquah in 1992, based on a HEC-2 model that was calibrated to high-water marks for the January 1990 flood (Reference 103). Estimates of Issaquah Creek overbank flow entering the North Fork channel were made by assuming weir flow in two segments that correspond to relatively low sections along the channel banks. 110 The first (upstream) section was represented as a 500-foot-long weir located between Cross Sections C and D. The second (downstream) section was represented as a 200-foot-long weir between Cross Sections B and C. Average depths of flow over these sections under 1-percent-annual-chance flood conditions were estimated to be 0.5 and 0.3, respectively. Depths of flow for 2-, and 0.2-percent-annual-chance events were estimated to be approximately 0.2 foot lower and 0.5 foot higher, respectively, than the 1-percent-annual-chance flow depths. A broad-crested weir coefficient of 2.5 was assumed for computing overbank flow. Approximately 440 cfs additional flow enters North Fork Issaquah Creek from Issaquah Creek between Cross Sections C and D, and approximately 80 cfs enters between Cross Sections B and C. The floodway analyses considered only the basin flows and did not include additional flows due to overtopping. A detailed backwater model was created for the entire study reach using the February 1991 release of HEC-2 (Reference 104). An existing HEC-2 model of the lower portion of the study reach was obtained from King County and modified for purposes of the restudy. The physical geometry of the North Fork Issaquah Creek channel was represented by 11 cross sections surveyed in 1989 and 1994. Channel cross sections were surveyed in April and May 1989 by David Evans and Associates (DEA) for King County at six locations from the mouth to just upstream of SE 64th Place. An additional five channel cross sections were surveyed in October and November 1994 by nhc to define the upstream portion of the study reach. Floodplain geometry was estimated from a 2-foot contour mapping obtained from the City of Issaquah Department of Public Works in digital and hard-copy format. The contour mapping was prepared by David C. Smith and Associates of Portland, Oregon, based on photography dated April 11, 1989. Eight bridges, one rectangular weir, and a complex multiple- culvert crossing at the I-90 interchange are represented in the North Fork Issaquah Creek HEC-2 model. The data to define these structures were obtained from DEA surveys made for the lower portion of the study reach in 1989, from nhc field surveys made for the upper portion of the study reach in 1994, and from construction drawings for the I-90 interchange obtained from the WSDOT. 111 A small footbridge located approximately 20 feet upstream of the rectangular weir in the upstream portion of the study reach was not represented in the model. The footbridge spans the full channel without any fill or encroachments, and appeared unlikely to survive a major flood. Approximate methods were sued to assess the complex culvert crossing at the I-90 interchange. The existing crossing consists of an original dual-culvert system that was augmented by a large bypass culvert after the original system failed to perform satisfactorily. The original I-90 crossing design was constructed in 1968/1969. It is a complex design with three sections of dual 42-inch- and 54- inch-diameter culverts at different invert elevations and slopes, alternating with two open-water sections in the areas enclosed by on and off ramps between I-90 and East Lake Sammamish Parkway. In each of the dual-culvert segments, one of the two culverts is constructed with zero slope. Sediment obstruction of the upstream (3.5-foot-diameter) zero-slope culvert is believed to have been a major cause of upstream flooding following completion of the original crossing design. The I-90 crossing design was substantially modified in 1973, with the addition of a single 260-foot-long, 66-inch-diameter bypass culvert beneath East Lake Sammamish Parkway. The complex crossing at the I-90 interchange is represented in the HEC-2 model by an equivalent culvert that was determined using the WSDOT’s HY-8 culvert program. In determining an equivalent culvert, it was assumed that the zero-slope culvert from the original design is completely ineffective due to sediment obstruction, consistent with verbal reports that such blockage has occurred during past flood events. All remaining culverts were assumed to be in good hydraulic condition and free of blockages. Individual rating curves based on a constant (approximately 1-percent-annual-chance) tailwater level of 66.5 feet were determined for the two active flow paths, and manually summed to derive a composite rating curve. An equivalent culvert was then determined by trial and error so that the equivalent rating curve matches the composite rating curve at the 1-percent-annual-chance discharge. The equivalent culvert used in the HEC-2 model is a single 6.3- foot-diameter culvert that is 250 feet long and follows the 112 alignment and slope of the bypass culvert under East Lake Sammamish Parkway. Channel roughness values (Manning’s ―n‖) in the HEC-2 model were determined by calibration to observed water levels and by reference to USGS Water Supply Papers 1849 and 2339, which discuss roughness characteristics of natural channels and floodplains (References 105 and 106). Manning’s ―n‖ values ranged from 0.03 to 0.12 for channel sections and from 0.06 to 0.20 for overbank areas. The highest channel roughness values correspond to reaches of the channel having well-established trees and other vegetation within the sections coded in the HEC-2 model as being the main channel section. The values presented in the model are reasonable in relation to values presented by the USGS (1978 and 1989) (Reference 106). Inundated areas that do not convey flow were assigned ―n‖ values of 0.99 or higher. High ―n‖ values were defined during the hydraulic analysis of the 1-percent-annual-chance flood condition and were used to balance the horizontal distribution of main- channel and overbank flows, with consideration of contraction and expansion of flow upstream and downstream of bridge crossings. Starting water-surface elevations for the analysis assume coincident peak water levels in the main stem Issaquah Creek channel. Coincident peaks were assumed because 1-percent- annual-chance flood conditions in the lower reach of North Fork Issaquah Creek will be dominated by flows that originate from the main stem channel. There are floodplain boundary discontinuities between the North Fork Issaquah Creek and main stem channels in the vicinity of Cross Section D. Issaquah Creek floodplain boundaries through this reach were last studied in 1977. Most of the Zone X areas between the North Fork Issaquah Creek and main stem channels are subject to inundation during a 1-percent-annual-chance flood on Issaquah Creek. The normal depth of flow was used to determine the starting water- surface elevation for the floodway analysis. The flood risk in the upper study reach from SE 66th Street to the downstream crossing at the I-90 interchange is highly dependent on culvert maintenance at the I-90 interchange and on channel 113 aggradation upstream from the rectangular weir located in this reach. At the I-90 interchange, it was assumed for the restudy that the zero-slope culvert of the original design is fully obstructed, but that the second (sloping) culvert from the original design plus the bypass culvert are both maintained to be in good hydraulic condition. It was further assumed that the channel from the SE 66th Street bridge to the rectangular weir is not prone to aggradation, which would cause a significant reduction of the channel capacity. The floodway boundaries developed in the restudy were computed with the HEC-2 model based on the North Fork basin 1-percent- annual-chance discharge of 315 cfs, which excludes any additional flow originating from the main stem Issaquah Creek. The starting water level for the encroachment analyses was set at 1 foot above the normal depth of flow for the 1-percent-annual-chance discharge of 315 cfs. The stream has a small active channel, typically approximately 10 feet wide and 3 feet deep, which is contained within a larger main channel that is typically approximately 35 to 50 feet wide and 8 feet deep. Top-of-bank stations in the HEC-2 model are coded to reflect the smaller active channel in order to recognize substantial variations in roughness across the larger main channel. However, top-of-bank stations corresponding to the larger main channel are more appropriate in the context of determining minimum floodway widths. The floodway width and other floodway data that correspond to encroachment limits set at the top of the main channel banks were incorporated in Table 6, ―Floodway Data.‖ The profile for North Fork Issaquah Creek was revised as a result of the restudy. Bear Creek - The restudy of Bear Creek included detailed and approximate hydraulic analyses to estimate floodplain and floodway boundaries along the entire study reach. Detailed methods were used to determine the floodway boundaries and estimate the majority of the floodplain along Bear Creek. Approximate methods were used to determine depths of flow and inundation limits in the overbank area associated with a flow split downstream of NE 95th Street near the Friendly Village mobile- home park. At the upstream end of the study reach, the detailed hydraulic analyses were extended approximately 420 feet upstream 114 of Avondale Road NE to tie into the previous study (Reference 94). Because discharges for intermediate points along the main stem of Bear Creek appeared unreasonable in the previous study, new discharges were computed based on a combination of the peak flows at the mouth of Bear Creek and the distribution of flows across the study reach computed by Entranco Engineers, Inc., in the 1993 HSPF hydrologic analysis (Reference 108). To determine the flow at any point along Bear Creek, the appropriate recurrence interval flow at the downstream end of the study reach, from the previous study, was multiplied by the ratio of discharges at the two locations from the Entranco analysis. Discharges along Bear and Evans Creeks were incorporated in Table 2, ―Summary of Discharges.‖ Evans Creek - Discharges from the previous study dated September 1989 were used directly at three locations in the HEC-2 model: at the downstream end of the study reach on Bear Creek, near the mouth of Evans Creek, and at the upstream end of the study reach above the confluence with Cottage Lake Creek. Discharges at other points in the study reach were recomputed after review of the previous model indicated discharges at intermediate points were not consistent or reasonable. Cottage Creek - The hydraulic analyses performed for the restudy only extended up Cottage Lake Creek approximately 150 feet to include the entire width of the floodplain shared jointly by the two creeks. No further analysis or floodplain mapping was performed for Cottage Lake Creek The KCSWM developed backwater models of Bear, Evans, and Cottage Lake Creeks for the 1990 Bear Creek Basin Plan using the USACE HEC-2 model (Reference 104). The HEC-2 model was modified as follows:  More detailed cross-section data from a recent LOMR issued April 28, 1994, on lower Bear Creek were substituted for the King County data for the reach between State Route 202 and Union Hill Road (Reference 109).  The representation of the Union Hill Road bridge was updated to reflect the construction of a new bridge in 1994. 115  The KCSWM HEC-2 model was augmented with additional detailed cross-section data from a 1986 hydraulic investigation for the reach between Union Hill Road and the Redmond Animal Clinic (Reference 110).  Encroachment cards in the KCSWM HEC-2 model, used to limit effective flow areas at bridges, were replaced with NH cards to facilitate floodway analyses. The locations of the fully expanded flow sections were also adjusted consistent with recommendations in the HEC-2 User’s Manual.  The model configuration at several bridges was updated to more accurately simulate roadway overtopping and corresponding hydraulic losses.  Split-flow analyses were included to represent areas in the Bear and Evans Creeks models where significant flow exits the main channel and flows in a hydraulically separate flow path before returning to the main channel downstream.  The Bear Creek model was updated to reflect recent bridge replacements on Avondale Road NE at the two most upstream crossings, approximately at River Miles 5.4 and 5.7. Updated bridge geometry was based on nhc field surveys performed in August 1995.  The model was calibrated to high-water marks from the January 18, 1986, and January 10, 1990, flood events. Calibration led to modifications in Manning’s ―n‖ roughness values and the addition of several intermediate cross sections. The physical geometry of the Bear Creek channel was represented by 74 surveyed cross sections. These cross sections were developed primarily by the KCSWM based on field surveys by DEA in 1987. Surveyed cross sections were extended by the KCSWM using the 1987 aerial topographic mapping prepared by David Smith and Associates. Some cross sections were further extended by nhc to encompass the entire Bear Creek floodplain. Intermediate cross sections were added at several locations to improve the model’s stability and accuracy or as necessary for computation of bridge expansion and contraction losses. These were developed by interpolating the channel portion of adjacent cross sections and extending the overbanks based on the topographic base map. 116 Simulated water-surface elevations, field reconnaissance, and anecdotal reports from residents indicate that during severe floods, flow breaks out of the main Bear Creek channel downstream of NE 95th Street and passes to the east of the Firneldy Village mobile- home park. This split flow travels overland in a southerly direction, joins floodwater from Evans Creek, and returns to the Bear Creek system near the confluence of these creeks. The split flow was modeled in the HEC-2 model using the weir split-flow option. The split flow returns to Bear Creek via the Evans Creek overbank so the modeled Evans Creek discharges were modified to reflect this additional flow. Because the Bear Creek split flow affects water-surface elevations in Evans Creek, and the two creeks jointly share an extensive floodplain at their confluence, the restudy included detailed hydraulic modeling of Evans Creek from its mouth at Bear Creek upstream to River Mile 0.74. Roughness values (Manning’s ―n‖) used in the HEC-2 model were determined by calibrating the Bear Creek model to the January 18, 1986, and January 10, 1990, flood events. High-water data for these events were obtained from various sources, including a report by CH2M HILL for the City of Redmond (Reference 111); a hydraulic analysis by CH2M HILL for the WSDOT (Reference 112); and photographs by the City of Redmond, the owners of Friendly Village, and the owners of the Redmond Animal Clinic. Anecdotal reports of flooding were also provided by the owner of the farm near the confluence of Bear and Evans Creeks and the owners of property near the NE 106th and NE 116th Street crossings. These events are the most significant floods recorded in recent history and provide useful data for calibration of roughness coefficients both in the channel and on the overbank floodplain. Most of the calibration data are for the reach of Bear Creek downstream of NE 95th Street. For other reaches of the creek for which little or no calibration data were available, roughness coefficients were estimated using engineering judgment and reference to classical publications (References 113 and 114). Manning’s ―n‖ values range from 0.045 to 0.075 for the main channel and from 0.050 to 0.200 for the overbank and floodplain. Starting water-surface elevations at the downstream end of the Bear Creek restudy reach were extracted from the most recent approved LOMR for lower Bear Creek by the Montgomery Water Group, Inc., (References 115-117). 117 The 1987 aerial photogrammetry and base maps show that the restudy reach of Bear Creek (between State Route 202 and the uppermost Avondale Road crossing) is approximately 0.4 mile longer than that shown in the previous study profiles. This could be the result of changes in the stream channel but is most likely a result of improved photogrammetric techniques. The revised profile panels are measured in feet above State Route 202 along the restudied portion of Bear Creek. The floodplain boundaries for the 1-, and 0.2-percent-annual- chance events were taken from a topographic work map at a scale of 1:2,400. The base map was obtained from the KCSWM and was prepared by David Smith and Associates from aerial photographs taken in March 1987. The floodway boundaries developed in the restudy were computed with the HEC-2 model, generally with the assumption of equal- conveyance reduction from each side of the floodplain (HEC-2 encroachment method 4). The floodway model run was complicated by several factors. First, subsequent to the preparation of the previous study, several large fills were placed in the floodway fringe, thus using a portion of the allowable floodway surcharge. These fills include a large fill on the left bank downstream of Union Hill Road, a fill on the right bank between Union Hill Road and the Avondale Road Extension, the roadway fill of the Avondale Road Extension, and a large fill on the left bank upstream of the Avondale Road Extension to the north side of Union Hill Road. Similarly, several bridges have been replaced with large structures subsequent to the previous hydraulic analysis, tending to lower water-surface elevations for the same discharges. Based on NFIP regulations, target water-surface elevations for the floodway runs were based on a 1 foot surcharge above baseline conditions at the time of the previous study of 1978. The second factor complicating the floodway analysis is that the current hydraulic modeling shows significant deviations from the computed 1-percent-annual-chance water-surface elevations reported in the previous study, particularly in the reach below the confluence with Evans Creek. Some of the differences result from the floodplain modifications described above. However, further investigation showed that the greatest portion of the difference is a result of the selection and application of the hydraulic model. The previous study analysis was performed with the USACE, Seattle District, step-backwater model (1983) using a total of six channel cross sections and one bridge to define the reach between State Route 202 and the confluence of Bear and Evans Creeks. In 118 contrast, the restudy uses the USACE HEC-2 model and a total of 30 channel cross sections and four bridges in this reach. A third factor complicating the floodway analysis was that HEC-2 is unable to use the split-flow option and automatic floodway encroachment options together. This necessitated the construction of a model of the existing condition with the split flow removed (a pseudo 1-percent-annual-chance flood model) as the basis for the floodway runs. Finally, although the automated encroachment option in HEC-2 is designed to meet target water-surface elevations at each cross section, there are cases where the model does not limit the surcharge to the desired elevation or results in an unusual floodway shape. Therefore, the floodway model runs were performed in the following manner:  A baseline HEC-2 model was configured corresponding to the 1978 conditions using recent channel survey data with the overbanks modified to remove fills and bridge modifications that have occurred since 1978. This model was run to determine appropriate regulatory BFEs.  Target floodway elevations were computed as the regulatory BFEs plus 1 foot.  A floodway HEC-2 model was configured to reproduce results of the existing condition 1-percent-annual-chance profile while eliminating the split-flow cards. This model was run using only the flow in the main channel (minus the portion that had previously been computed as split flow) to develop a pseudo 1- percent-annual-chance profile that provided HEC-2 with a basis for the automatic encroachment run.  A second profile was run using the floodway model with the full 1-percent-annual-chance discharge and the equal- conveyance reduction encroachment option (HEC-2 method 4). Target surcharges as established using the 1978 baseline model were input for this model run.  The floodway model was revised iteratively using manual encroachments (HEC-2 method 1) to meet surcharge targets (regulatory BFEs plus 1 foot) and provide a reasonable shaped floodway. Using the final HEC-2 floodway model, floodway widths were computed at each cross section. Between cross section, the floodway boundaries were interpolated. As a result of the restudy, 119 Table 6, ―Floodway Data,‖ was revised. The ―Regulatory‖ and ―Without Floodway‖ elevations are based on existing conditions. The surcharge is the difference between the existing ―With Floodway‖ elevation and the 1-percent-annual-chance water- surface elevation using the 1978 baseline model. Flood Profile Panels for Bear and Evans Creeks were revised as a result of the restudy. South Fork Skykomish River - The cross-section data for the study along the South Fork Skykomish River was taken from field surveys and topographic mapping prepared by David C. Smith and Associates, Inc. The water-surface elevations of the floods of the selected recurrence intervals were computed using HEC-2. The 1- percent-annual-chance floodplain boundary was delineated using water-surface elevation determined at each cross section. Between cross sections, the 1-percent-annual-chance floodplain was interpolated using topographic mapping at a scale of 1:2,400, with contour intervals of four feet. Channel and overbank roughness factors (Manning’s ―n‖) used in the hydraulic analyses were based on engineering judgment. The range of channel roughness factors of 0.038 to 0.048 and overbank roughness factors of 0.080 to 0.120 were used to model the South Fork Skykomish River. Middle Fork Snoqualmie River - The cross-section data for the study along the Middle Fork Snoqualmie was taken from field surveys and topographic mapping prepared by David C. Smith and Associates, Inc. The water-surface elevations of the floods of the selected recurrence intervals were computed using HEC-2. The 1- percent annual chance floodplain boundary was delineated using water-surface elevation determined at each cross section. Between cross sections, the 1-percent-annual-chance floodplain was interpolated using topographic mapping at a scale of 1:2,400, with contour intervals of 2 and 10 feet. Flood profiles for the Middle Fork Snoqualmie River were calibrated using high-water marks at the Mount Si Road bridge. Channel and overbank roughness factors (Manning’s ―n‖) used in the hydraulic analyses were based on engineering judgment. The hydraulic profile for the Middle Fork Snoqualmie River was generally calibrated to a known flood-stage water-surface elevation (at the bridge where a high-water mark was identified). The estimated roughness coefficients for this study were adjusted to attain a relatively close elevation match to known high-water marks. 120 North Fork Snoqualmie River - The cross-section data for the study along the North Fork Snoqualmie Rivers was taken from field surveys and topographic mapping prepared by David C. Smith and Associates, Inc. The water-surface elevations of the floods of the selected recurrence intervals were computed using HEC-2. The 1-percent-annual-chance floodplain boundary was delineated using water-surface elevation determined at each cross section. Between cross sections, the 1-percent-annual-chance floodplain was interpolated using topographic mapping at a scale of 1:2,400, with contour intervals of 2 and 10 feet. The range of channel roughness factors of 0.035 to 0.046 and overbank roughness factors of 0.070 to 0.100 were used to model the North Fork Snoqualmie River. The floodway was determined based on equal-conveyance reduction from both sides of the floodplain. Floodway widths were determined at each cross section, and between cross sections the floodway boundaries were interpolated. In cases where the floodway line is collinear with the 1-percent-annual-chance floodplain line, only the floodway line has been shown. 3.2.5 Revision 5 North Creek - The hydraulic analyses for the revised study were performed using the USACE HEC-2 computer program (Reference 97). The physical geometry of the North Creek channel was represented by 39 cross sections surveyed by nhc between December 1993 and February 1994. Only the channel portion of each section was surveyed. The cross sections were extended to include the floodplain using 2-foot-contour-interval mapping provided by the City of Bothell Department of Public Works (Reference 120) and the Quadrant Company. The HEC-2 model contains the surveyed sections as well as sections synthesized from the survey data to define the characteristics of bridges and complex study areas. The starting water surface elevations were determined from the flood profiles computed for the original study for the 10-, 2-, and 1-percent-annual-chance events. The 0.2-percent-annual-chance flood profile was not computed for the previous study due to complex hydraulic conditions downstream of the County line. Therefore, the starting water-surface elevation for the 0.2-percent- annual-chance event was determined based on normal depth. 121 Channel roughness coefficients (Manning’s ―n‖ values) used in the HEC-2 model were determined by calibrating the model to conditions observed in the field on December 10, 1993. The December 10 calibration event generally stayed within the channel banks. Therefore, floodplain ―n‖ values were estimated using engineering judgment and reference to classical publications (References 98 and 99). The final calibrated ―n‖ values for North Creek are shown in Table 4, ―Manning’s ―n‖ Values.‖ Twelve bridges are represented in the HEC-2 model for the revised reach of North Creek. The data used to define these structures were obtained during nhc field surveys. No other permanent structures were identified that would significantly affect flood levels. Downstream of the King-Snohomish County line, North Creek is confined between levees. At the County line, tieback levees have been constructed across both the left and right floodplains to direct upstream flow into the North Creek channel. Just upstream of the County line, in the Monte Villa Center development, a setback levee parallels the channel to the east. At the County line, it connects to the downstream levee. At its upstream end, it tapers into higher ground near 240th Street Southeast. The 1-, and 0.2-percent-annual-chance floodplain boundaries were delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps at a scale of 1‖=200’, with a contour interval of 2 feet (Reference 121). North Creek (LOMR) - The base condition HEC-2 hydraulic model (Reference 97) for North Creek was revised to reflect the levee system and new topographic information. The use of a revised base condition hydraulic model resulted in both increases and decreases in the BFEs along the revised reach of North Creek within the levee system. The BFEs decreased by 0.2 foot to 0.3 foot from approximately 400 feet upstream of I-405 to just downstream of the southernmost North Creek Parkway bridge crossing, and increased by 0.3 feet to 1.4 feet from approximately 500 feet upstream of the southernmost North Creek Parkway bridge crossing to just upstream of the northernmost North Creek Parkway bridge crossing. The Special Flood Hazard Area (SHFA) is contained by the levee system along this reach of North Creek and, therefore, the SFHA 122 width decreased and the areas protected form 1-percent-annual- chance flooding by the levee system have been redesigned Zone X. The floodway for the reach of North Creek from I-405 to 240th Street Southeast was computed based on incorporating the credited levee system and equal conveyance reduction from each side of the flooding. 3.2.6 Revision 6 Tolt River - The hydraulic analysis was performed by Harper Righellis Inc. using the USACE HEC-2 step backwater computer program (Reference 97). Data for the cross sections were taken from field surveys performed in August through November, 1994 and from data extracted from planimetric maps. The starting water-surface elevation was obtained by the slope-area method based on an estimated slope of the energy grade. The roughness coefficients were adjusted to calibrate the hydraulic model to observed high water marks, and the range of values is shown in ―Manning’s ―n‖ Values‖, Table 4. From just upstream of the abandoned railroad (Snoqualmie Valley Trail) to the Holberg levee area, Tolt River is confined between levees. However, these levees do not meet FEMA freeboard requirements. Therefore, the water-surface profiles for the area affected by the levees are computed for both with and without consideration of the levees. The 1-percent-annual-chance floodplain boundaries for Tolt River were delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps at a scale of 1:2,400, with a contour interval of 2 feet (Reference 123). South Fork Snoqualmie River – The study reach is called the Upper South Fork Snoqualmie River for the purposes of this study to better describe the affected flooding area. Topographic maps from studies completed by Harper Righellis, Inc. for the South Fork were used for this restudy (Reference 126). Cross sections for the mainstem were converted from an HEC-2 data deck from a study currently underway by the USACE (Reference 127). Overbank portions of some of these cross sections were modified using the new topographic maps as produced by Harper Righellis Inc. Cross sections for the Middle 123 Fork and the South Fork upstream of I-90 were converted from the HEC-2 data deck from a study recently completed by Harper Righellis Inc. (Reference 128). 3.2.7 Revision 7 Snoqualmie River - Analyses of the hydraulic characteristics of flooding from the studied sources were performed to provide estimates of the elevations of floods of the 10-, 2-, 1-, and 0.2- percent-annual-chance recurrence intervals. Users should be aware that flood elevations shown on the Digital Flood Insurance Rate Map (DFIRM) represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles (Exhibit 1) or in the Floodway Data table in the FIS report. Flood elevations shown on the DFIRM are primarily intended for flood insurance rating purposes. For construction and/or floodplain management purposes, users are cautioned to use the flood elevation data presented in this FIS in conjunction with the data shown on the DFIRM. The prior USACE hydraulic analyses were reviewed in detail, and appropriate revisions were made. The revisions include updating some cross sections based on more recent channel surveys and modifying the effective limits of flow, roughness coefficients, expansion and contraction coefficients, peak flows, and starting condition methods. Water surface elevations (WSELs) for the 1-percent-annual-chance flood on the Snoqualmie River, Ribary Creek, and Gardiner Creek were computed using the USACE Hydrologic Engineering Center River Analysis System (HEC-RAS Version 2.2 Reference 131), step-backwater computer program. Because the Middle Fork and South Fork peak flows are near coincident, all the hydraulic analysis models assume coincident peak flows; therefore, the starting condition for each model is the WSEL of the appropriate cross section of the downstream model. The main stem model starting WSEL was taken from the FEMA published WSELs. The overflow values from Middle Fork to South Fork were estimated using engineering judgment based on the terrain, because cross sections were not available at the split location to yield a more precise computation. The Gardiner Creek and Ribary Creek starting WSELs were based on a known WSEL at the downstream end. 124 Roughness coefficients (Manning’s ―n‖) values for South Fork Snoqualmie River, Snoqualmie River main stem, Middle Fork Snoqualmie River-Overflows, Gardiner Creek, and Ribary Creek are shown in Table 4. Ribary Creek detailed study elevations were superseded by the elevations of South Fork using the ―without levee‖ analysis. The floodplain delineation at the confluence of Gardiner Creek with South Fork was based on the South Fork model. Because the levees on South Fork, beginning at the I-90 bridge and extending downstream to the Snoqualmie Valley Trailbridge, did not meets FEMA’s standards for providing protection from the 1-percent-annual-chance flood, ―with levee‖ and ―without levee‖ conditions were analyzed. To reflect the levees on both sides of the river, the following analyses were conducted: ―with both levees‖, ―without right levee‖, ―without left levee.‖ The regulatory floodway along the Snoqualmie River study reach was determined using the equal-conveyance reduction option in the HEC-RAS backwater model from each side of the floodplain. The Floodway Data Table and the FIRM show the results of the floodway computation for the studied reach of the Snoqualmie River. The boundaries of the area inundated by the 1-percent-annual- chance flood were plotted on USGS 1:24,000-scale Digital Raster Graphic (DRGs) enlarged to 1:2,400 (Reference 132). Topographic data, roads, and canals on the DRGs; recent aerial photographs; and field observations were reviewed to aid in plotting the flood boundaries between cross sections. Inundated areas with little or no flow were identified. More precise data on the extent of inundation may be determined at any given location by using the computed WSEL and detailed field surveys of the land surface. Issaquah Creek - Analyses of the hydraulic characteristics of flooding from the sources studied were performed to provide estimates of the elevation of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the DFIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. Flood elevations shown on the DFIRM are primarily intended for flood insurance rating purposes. For construction and/or floodplain management 125 purposes, users are cautioned to use the flood elevation data presented in this FIS in conjunction with the data shown on the DFIRM. Cross-section and bridge data for the backwater analysis on Issaquah Creek and East Fork were field surveyed in April and May 2000 and February 2001 to obtain invert elevations and other hydraulic parameters. To define overbank areas and areas in- between cross sections, these data were supplemented with City of Issaquah digital mapping with a contour interval of 2 feet from Nies based on a March 1988 aerial survey. High-water mark data based on community input were also field surveyed as part of this study. WSELs of floods of the selected recurrence intervals on Issaquah Creek, East Fork, and Gilman Boulevard Overflow were computed using the USACE HEC-RAS, Version 3.0.1, step-backwater computer program (Reference 140). The hydraulic analyses for this study were based on unobstructed flow. Therefore, the flood elevations shown on the profiles are considered valid only if hydraulic structures remain unobstructed, are operated properly, and do not fail. All elevations are referenced to North American Vertical Datum of 1988 (NAVD). Refer to section 3.3 Vertical Datum for more information. To obtain up-to-date elevation information on NGS ERMs shown on the DFIRM, please contact the Information Services Branch of the NGS at (301) 713-3242 or visit their website at www.ngs.noaa.gov. Map users should seek verification of non-NGS ERM monument elevations when using these elevations for construction or floodplain management purposes. The starting WSELs on Issaquah Creek at the northern corporate limit of the City of Issaquah were based on previous studies. The water surface elevations published in the King County FIS closely matched the predicted elevations for this analysis at that location. The starting WSELs on East Fork were developed through normal depth computation using the slope-are method. The regulatory WSELs were influenced by backwater from the main stem of Issaquah Creek, as shown on the Flood Profiles. The starting WSELs of floods of the selected recurrence intervals on the Gilman Boulevard Overflow and the main stem of Issaquah Creek were set using computed WSELs at hydraulic control sections. The upper main stem starting WSEL was set at the upper 126 fish hatchery weir control section. The Gilman Boulevard Overflow model starting WSEL was set below a culvert control section. Channel and overbank roughness factors (Manning’s ―n‖ Values) used in the hydraulic computations were chosen by engineering judgment and were based on field observations of the stream and floodplain areas and on hydraulic calibration of flood profiles to available high-water mark data. The February 8, 1996, flood event was used for hydraulic model calibration. Model calibration results are discussed in detail in the calibration and bridge improvement memorandum by the Montgomery Water Group for Issaquah Creek, East Fork, and the Gilman Boulevard Overflow path are listed in Table 4. Locations of selected cross section used in the hydraulic analyses are shown on the Flood Profiles. For stream segments for which a regulatory floodway was computed (see Section 4.2), selected cross-section locations are also shown on the DFIRM. The NFIP encourages State and local governments to adopt sound floodplain management programs. To assist in this endeavor, each FIS provides 1-percent-annual-chance floodplain data, which may include a combination of the following: 10-, 2-, 1-, and 0.2- percent-annual-chance flood elevations; delineations of the 1-, and 0.2-percent-annual-chance floodplains; and the 1-percent-annual- chance floodway. This information is presented on the DFIRM and in many components of the FIS, including Flood Profiles, Floodway Data tables, and the Summary of Discharges table. Users should reference the data presented in the FIS as well as additional information that may be available at the local community map repository before making flood elevation and/or floodplain boundary determinations. Overflows from Issaquah Creek and East Fork are shown on the maps as shallow flooding zone (Zone AO) with average depths identified. To provide a national standard without regional discrimination, the 1-percent-annual-chance flood has been adopted by FEMA as the base flood for floodplain management purposes. The 0.2-percent- annual-chance flood is employed to indicate additional areas of flood risk in the community. For each stream studied by detailed methods, the 1- and 0.2-percent-annual-chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated, using digital topographic maps with contour intervals of 2 feet (Reference 142). 127 The 1- and 0.2-percent-annual-chance floodplain boundaries are shown on the DFIRM. On this map, the 1-percent-annual-chance floodplain boundary corresponds to the boundary of the areas of special flood hazards (Zones AE, AH, and AO), and the 0.2- percent-annual-chance floodplain boundary corresponds to the boundary of areas of moderate flood hazards. In cases where the 1- and 0.2-percent-annual-chance floodplain boundaries are close together, only the 1-percent-annual-chance floodplain boundaries may lie above the flood elevations but cannot be shown because of limitations of the map scale and/or lack of detailed topographic data. Encroachment on floodplains, such as structures and fill, reduces flood-carrying capacity, increases flood heights and velocities, and increases flood hazards in areas beyond the encroachment itself. One aspect of floodplain management involves balancing the economic gain from floodplain development against the resulting increase in flood hazard. For purposes of the NFIP, a regulatory floodway is used as a tool to assist local communities in this aspect of floodplain management. Under this concept, the area of the 1-percent-annual-chance floodplain is divided into a floodway and a floodway fringe. The floodway is the channel of stream, plus any adjacent floodplain areas, that must be kept free of encroachment so that the 1-percent-annual-chance flood can be carried without substantial increases in flood heights. Minimum Federal standards limit such increases to 1 foot, provided that hazardous velocities are not produced. The floodways in this study are presented to local agencies as a minimum basis for additional floodway studies. The floodways presented in this study were computed for certain stream segments on the basis of equal conveyance reduction from each side of the floodplain. Floodway widths were computed at cross sections. Between cross sections, the floodway boundaries were interpolated. The results of the floodway computations are tabulated at selected cross sections. In cases where the floodway and 1-percent-annual-chance floodplain boundaries are either close together or collinear, only the floodway boundary has been shown. The area between the floodway and 1-percent-annual-chance floodplain boundaries is termed the floodway fringe. The floodway fringe encompasses the portion of the floodplain that could be completely obstructed without increasing the water- surface elevations of the 1-percent-annual-chance flood more than 1 foot at any point. The Flood Profiles, Floodway Data tables, and the DFIRM show the results of the floodplain and floodway 128 computations for the studied reaches of Issaquah Creek, including East Fork. Floodways were not computed for the Gillman Boulevard Overflow. The Gillman Boulevard Overflow area is designated on the DFIRM as a breakout flow area, where the flow conveyance during the base flood must be maintained to avoid increasing downstream flood hazards in Issaquah Creek. This breakout flow area extends from the left overbank (looking downstream) of Issaquah Creek between Cross Sections M and N toward the west along Gillman Boulevard. 3.2.8 Revision 8 Cedar River – King County Unincorporated Area The river was modeled using HEC-RAS 2.2. The computations are based on sub-critical flow and use the slope (normal depth) method for the starting condition. The HEC-RAS model conforms to the criteria of hydraulic modeling. There are a few locations where water-surface elevations are higher than the end points of cross sections; but in all cases, the end points are at the effective flow limit for that cross section. Aside from directly within some bridges, negative floodway surcharges are limited in location and are negligible (i.e., all are much less than -0.1 feet). Cedar River –City of Renton Area - Detailed methods were used to define the hydraulic characteristics of the 5.36-mile study reach. A HEC-RAS model was previously created for the main channel and overbank floodplain of the Cedar River from Lake Washington upstream to 149th Avenue Southeast (also referred to as Jones Road or the Elliot bridge). During this current study, the model was modified to include four additional split flow reaches and updated survey data at select cross sections. The first of these split flow reaches occurs at Maplewood Golf Course (about river mile 4.5). This reach, designated as the ―Golf Course Split‖, defines the flow path where a portion of the 0.2-percent-annual-chance flood flow leaves the main channel and travels overland through the golf course before rejoining the main channel at approximately river mile 2.8. A second split flow reach, termed the ―Maplewood Overflow‖, routes floodwaters through a portion of the Maplewood subdivision. Another split flow reach, designated as the ―Old Channel Split‖, was defined for the portion of the old channel that was cut-off as a result of the landslide. The fourth and final split flow reach occurs south of Highway 169 between river miles 4.2 and 5.36. Floodwaters enter this reach, designated as the ―Highway 169 Overtopping Split‖, between river miles 5.0 and 5.3 129 and are prevented from rejoining the main channel again until river mile 4.5 (approximately 140th Ave. SE). One of the most notable features of this model is that the channel geometry used to determine flood risk represents the maximum ―allowable‖ bed elevation prior to mandatory dredging of the lower river as detailed in the Cedar River at Renton Flood Damage Reduction Project Operation and Maintenance Manual (O&M Manual) (Reference 144). This future aggraded condition depicts a significantly higher channel bed profile than existed at the time of the channel surveys for this study. Because the maximum ―allowable‖ bed profile defines the highest possible bed profile allowed in the O&M Manual, FEMA requires that it must be considered when determining flood risk. The difference in the allowable bed and surveyed channel bed profiles is illustrated in Exhibit 1. The HEC-RAS model was used to compute water surface profiles for the 10-, 2-, 1- and 0.2-percent-annual-chance flood events, floodplain inundation limits for the 1-, and 0.2-percent-annual- chance events, and floodway boundaries for the 1-percent-annual- chance flood. Fifteen bridges influence hydraulic conditions within the study reach. Three other bridges completely span the river (the two I- 405 bridges and the Burlington Northern railroad bridge just downstream of I-405), and one other bridge is hydraulically lifted above the water surface during large flood events (the south Boeing bridge at river mile 0.75). The deck of the old railroad bridge at river mile 2.9 (now a pedestrian bridge) is above both the 1-, and 0.2-percent-annual-chance flows, and therefore only the bridge piers were included in the model. This was also the case with the 149th Avenue Southeast bridge, at the upstream end of the study reach. In two locations, immediately adjacent parallel bridges were modeled as a single bridge. This was done at the Houser Way and downstream pedestrian bridges, as well as at the Highway 169 and downstream pedestrian bridges. Seven of the bridges experience partial or complete pressure flow during the 1-percent-annual-chance flood and eight at the 0.2-percent-annual- chance flood. Sensitivity analysis showed that three of these bridges were best modeled using the pressure flow option for high flows while the remainder was more accurately simulated using the energy method for high flows. The three bridges modeled with the pressure flow option were: the pedestrian bridge under I-405, the Houser Way/pedestrian bridge, and Wells Avenue Bridge in downtown Renton. 130 Channel and overbank roughness coefficients (as represented by Manning’s ―n‖ values) were initially estimated from several established references (References 99 and 147). These values were further refined by calibrating the HEC-RAS model to two recent flood events, the flood of record on November 24, 1990 and a lesser event on November 30, 1995. The 1990 flood had a peak discharge of 10,600 cfs as estimated by the USGS at Gage 12119000 in downtown Renton, and the 1995 flood had a peak discharge of 7,650 cfs. Highwater marks were surveyed by the U.S. Army Corps of Engineers after both floods. Calibration was difficult at the downstream end of the study reach because the channel and overbank have changed significantly since the 1990 and 1995 events. The reach extending from Lake Washington upstream to Logan Avenue was dredged in 1986 and again in 1998, while periodic surveys showed that the channel experienced significant aggradation between dredging operations. In addition, a new floodwall-levee system was recently constructed downstream of Logan Avenue which would prevent water from leaving the main channel and flowing across the airport and Boeing property, as occurred during the 1990 event. Manning’s ―n‖ values in this reach were largely taken from a previously calibrated HEC-RAS model created by USACE to design the floodwall-levee system. Upstream of I-405 the current model calibrated fairly well to observed highwater marks. The resultant Manning’s ―n‖ values range from 0.02 to 0.045 in the main channel, which varies from 80 to 150 feet wide and has a gradually meandering planform with occasional gravel bars. Main channel ―n‖ values are typically 0.033 throughout most of this reach, but were raised in the vicinity of the old railroad bridge at river mile 2.9 to reflect the turbulence generated by the two sharp bends in the river and to match highwater marks surveyed just upstream. The channel banks are typically overgrown with dense vegetation such as blackberry bushes, while the floodplain varies from groomed lawn to thick brush. Manning’s ―n‖ values ranging from 0.03 to 0.15 were used on the overbank and floodplain. 131 Starting water surface elevations at the downstream end of the modeled reach were set at 17.06 feet (NAVD 88). Water levels in Lake Washington are regulated by the Chittenden Locks. This elevation corresponds to the maximum expected water surface elevation in Lake Washington between November 1 and March 31 (Reference 146), as well as the elevation used in the design of the flood protection project by USACE. The USACE designed and constructed a series of floodwalls and levees along the lower end of the study reach, extending from Lake Washington to just upstream of Logan Avenue. The levees and floodwalls, in conjunction with modifications to the south Boeing Bridge and a program of dredging, were designed to provide 1- percent-annual-chance flood protection at the 90 percent reliability level. Because the project is USACE certified, the reach was modeled with the levees and floodwalls in place, without the south Boeing Bridge (which is lifted hydraulically above the water during flood events), and using an aggraded bed scenario consistent with the maximum ―allowable‖ bed profile specified in the Cedar River at Renton Flood Damage Reduction Operation and Maintenance Manual (Reference 144). The flood profiles for the 10-, 2-, 1-, and 0.2-percent-annual- chance floods along the main stem of the Cedar River were generated using the HEC-RAS model, and are illustrated in Exhibit 1. The 1-percent-annual-chance floodway boundaries developed in this study were determined with the HEC-RAS model, generally with the assumption of equal conveyance reduction from each side of the floodplain (HEC-RAS method 4). At some locations, applying the automatic encroachment feature available in HEC- RAS produced flood elevation increases greater than 1 foot and resulted in an unusual floodway shape. As a result, the encroachments were manually adjusted using HEC-RAS method one until a reasonable floodway was established. Further upstream, the floodway was located at the edge of the active channel, existing wetlands, and salmon spawning channels, even though additional encroachment would be possible without causing greater than a 1 foot rise in water surface elevations. No separate floodway was computed for the split flow reaches because flow was assumed to be contained in the main channel by the floodway encroachments. Floodway widths were computed at each cross section. Between sections, the floodway boundaries were interpolated. The results 132 of the floodway analysis are tabulated for each cross section in Table 5. In locations where the floodway and the 1-percent- annual-chance floodplain boundary coincide, only the floodway boundary is shown. Kelsey Creek - Analysis of the hydraulic characteristics of flooding along Kelsey Creek and the West Tributary study reaches were performed using detailed methods. Detailed methods involved using a HECRAS (USACE, 2005) water surface profile computer model for Kelsey Creek and the West Tributary developed by nhc. The following sections describe the data, information, and assumptions used to construct the hydraulic model. Channel and Floodplain Topography The HEC-RAS model for Kelsey Creek and the West Tributary includes 197 and 42 cross sections, respectively. These cross sections serve to represent the geometry of the channel and floodplain along the study reach. Cross-section data for this study came from two different sources. Channel cross sections along Kelsey Creek were surveyed by the City of Bellevue in early 2006, while cross sections on the West Tributary were surveyed by nhc as part of a different project for the City of Bellevue Parks Department in 2004. Topographic data consisting of two foot contour intervals, provided by the City of Bellevue, were used to extend the surveyed channel cross sections to include the floodplain. Hydraulic Structures The hydraulic analysis of the Kelsey Creek and West Tributary study reaches includes 16 culvert, 31 bridge, 21 inline weir, and seven lateral weir structures. Within the HEC-RAS model, all culverts were modeled using the Highest Upstream Energy method, while bridges were modeled either with the Energy, or Pressure and/or Weir methods, depending on level of inundation. The 21 inline weirs are located on the main stem of Kelsey Creek between Cross Sections K and P, and generally consist of concrete grade control structures. Split Flow Lateral weir structures were utilized in the HEC-RAS model to transfer flow between the main stem of Kelsey Creek and an adjacent swale-like reach located in Kelsey Creek Park immediately to the west. As previously discussed an earthen embankment was 'failed' to allow overtopping flow in the main 133 stem to move into the swale. In this reach the current location of the creek is perched at an elevation above the adjacent swale, such that any overbank flow will be uncontained and move laterally. A split flow optimization routine was used for this analysis to balance water surface elevations in the main channel and discharges flowing into the swale reach. Starting Water Surface Elevation The downstream limit of the Kelsey Creek HEC-RAS model is located at the outlet of the culvert structure under I-405. Immediately downstream of this culvert outlet, the creek flows through a concrete fish ladder structure. Because the top of the structure is elevated approximately 8 feet above the receiving body of the water (Mercer Slough), and the flow is likely of mixed regime, i.e. rapidly transitions between super and subcritical, a critical flow depth was chosen as a starting water surface condition. Because the channel upstream of the 630-foot long I-405 culvert structure is deeply entrenched within a narrow gully, the floodplain extents are not significantly affected by starting water surface elevation. Thus, the choice of using the critical depth boundary condition is considered reasonable in this situation. Model Calibration Twelve high water marks along Kelsey Creek and the West Tributary were observed by City of Bellevue staff following the major flood event of October 20, 2003 (approximately 25-year return period). Initial channel and floodplain roughness factors (Manning's "n" values) were estimated based on field observations and engineering judgment. To calibrate the hydraulic model, these initial roughness factors were adjusted, but kept within a range of values that is consistent with past experience, until the computed water surface elevations closely matched the recorded high water mark elevations. The resulting channel and floodplain "n" values for Kelsey Creek and the West Tributary range from 0.035 to 0.06 and 0.035 to 0.15, respectively. Flood Profiles The 10-, 2-, 1-, and 0.2-percent-annual-chance flood profiles events for the Kelsey Creek and the West Tributary study reaches generated using the HEC-RAS model constructed for this study. These profiles represent conditions of unobstructed flow, meaning that the bridge and culvert openings as well as the main channel remain unobstructed during flood events. 134 Other Studies In 2003, a LOMR (Case No. 03-10-0399P) was submitted for the reach just upstream (south) of NE 6th Street and accepted by FEMA's reviewing agents (Montgomery, 2003). The upstream most 1-percent-annual-chance BFE for the current study is estimated at 252 feet, NAVD 88 located just upstream of NE 6th Street, while the 2003 LOMR uses a starting water surface elevation of 253 feet, NAVD 88, approximately 400 feet upstream. These values are sufficiently close to tie in the floodplain hazard areas and profiles between this and the 2003 LOMR studies. It should be noted that the limit of the floodway analysis is defined at the upper most cross section of this study, as a floodway did not exist for effective Kelsey Creek FIS, or the 2003 LOMR. Patterson Creek - A HEC-RAS computer model was created to simulate the hydraulic characteristics of the study reach. The model was used to compute water surface profiles corresponding to the 10-, 2-, 1-, and 0.2-percent-annual-chance floods, flood inundation limits for the 1-percent-annual-chance (base flood) and 0.2-percent-annual-chance events, and the floodway boundary for the 1-percent-annual-chance flood. One hundred and five cross sections are used in the HEC-RAS model to represent the channel and floodplain geometry along the study reach. Most of these cross sections were surveyed by Minister-Glaeser Surveying (MGS) in December 2005. Additional cross sections were interpolated from the survey and topographic data where needed. The cross-section surveys typically only included the stream channel from bank to bank. The floodplain was not surveyed; therefore, the overbank portion of each cross section was added using the digital topographic data developed for this study by 3Di-West. The topographic data was created using a combination of photogrammetric techniques and LIDAR data. Aerial photographs of the study reach were taken in March 2004. One culvert and 13 bridges influence hydraulic conditions within the study reach. The culvert is located at the upper-most crossing of the Redmond-Fall City Road. The 12 bridges included in the model are located on driveways to private residences or private and public roads; including State Highway 202. One bridge within the study reach, at NE 4th Place, was not included in the model because access to the private road was denied and therefore detailed information on the bridge was not available. All other bridges and the Redmond-Fall City Road culvert were surveyed by 135 nhc to obtain elevation data and structural geometry for input into the hydraulic model. The hydraulic model was extended downstream to the confluence with the Snoqualmie River to provide a more refined estimate of water levels at the downstream end of the detailed study reach. In accordance with the Guidelines and Specifications for Flood Hazard Mapping Partners (2003), the starting water surface elevation for the backwater model was assumed to be normal depth. The assumption of coincident peaks with the Snoqualmie River did not meet the acceptance criteria in the FEMA guidelines. Backwater flooding from the Snoqualmie River will influence the lower two miles of Patterson Creek. FEMA will use the information contained in this study and the information contained in the Snoqualmie River Floodplain Mapping Study (Section 10.8.3) to determine base flood elevations to be shown for this reach in the final FIS and mapped on the final DFIRM. Channel and overbank roughness factors (Manning’s ―n‖ values) used in the hydraulic computations were chosen using engineering judgment and were based on field observations, orthophotos, and published data. The ―n‖ values for the main channel of Patterson Creek range from 0.04 at the downstream end of the study reach to 0.12 in the heavily vegetated and narrow wetlands areas. Overbank ―n‖ values range from 0.02 on the golf course to 0.08 in the thick brush of the wetlands. There were no high water marks available to calibrate the model. The only marks available for calibration were the water surface elevations at each cross section noted by the surveyors. The discharge in the channel at the time of the survey varied from 1 to 23 cfs, depending on day and location. The model was calibrated to reproduce the observed stages, all the while keeping in mind the focus of the model is for a 1-percent-annual-chance event. All flood insurance studies are referenced to a specific vertical datum. The vertical datum provides a starting point against which flood, ground, and structure elevations can be referenced and compared. Until recently, the standard vertical datum used for newly created or revised studies was the National Geodetic Vertical Datum of 1929 (NGVD 29). With the finalization of the North American Vertical Datum of 1988 (NAVD 88), most studies are being prepared using NAVD 88 as the referenced vertical datum. The hydraulic analysis for Patterson Creek was conducted using the NAVD 88 vertical datum. Elevation conversion factors between the two vertical datums vary by location and can be 136 obtained from the National Geodetic Survey’s VERTCON utility (Reference 133). In general, elevations along the Patterson Creek study reach can be converted from NAVD 88 to NGVD 29 elevations by subtracting 3.58 feet. Refer to section 3.3 Vertical Datum for more information. Users should be aware that base flood elevations shown on the work map represent rounded whole foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data table. Base flood elevations shown on the work map are primarily intended for flood insurance rating purposes. For construction and/or floodplain management purposes, users are cautioned to use the flood elevation data presented in the Floodway Data table as well as the Flood Profiles in conjunction with the data illustrated on the work map. A Regulatory Floodway was delineated for Patterson Creek using the HEC-RAS model and following the FEMA Guidelines and Specifications for Flood Hazard Mapping Partners. In general, the floodway was developed using Encroachment Method 4 in HEC-RAS. Method 4 automatically computes encroachment stations by targeting a predefined surcharge (1 foot) while achieving an equal loss of conveyance on each overbank, where possible. At some locations, applying the automatic encroachment feature produced flood elevation surcharges significantly greater or less than 1 foot and/or resulted in an unusual floodway shape. As a result, the encroachments were manually adjusted using HEC-RAS Method 1 until a reasonable floodway was established. At some cross sections the floodway boundary coincides with the top of the channel banks. As required by FEMA, the floodway does not encroach into the active channel. Floodway widths were computed at each cross section. Between sections, the floodway boundary was interpolated based on topographic information and to reflect general hydraulic principles. The results of the floodway analysis are tabulated for each cross section in Table 5. The floodway boundary is also shown on the work map. In locations where the floodway and the 1-percent- annual-chance floodplain boundary coincide, only the floodway boundary is shown. Lower Snoqualmie River - A HEC-RAS unsteady flow hydraulic model was created to simulate the hydraulic characteristics of the 49-mile study reach. The model was used to compute water surface profiles corresponding to the 10-, 2-, 1-, and 0.2-percent- annual-chance floods, floodplain inundation limits for the 1-, and 137 0.2-percent-annual-chance events, and floodway boundaries for the 1-percent-annual-chance flood. All of the mainstem cross sections were surveyed in March 2004 by Minister-Glaeser Surveying using bathymetric techniques. The surveyed transects included only the wetted river channel from the water’s edge, bank to bank. Topographic data for the overbank portions of each cross section was derived from digital topographic data developed by 3Di-West. The topographic data was created using a combination of photogrammetric techniques and LiDAR data. Aerial photographs of the study reach were taken in March 2004. Six bridges have potential to significantly impact hydraulic conditions within the study reach. These include the following bridges on the Snoqualmie River: SR-202 Bridge at Fall City, Tolt Hill Road Bridge over the Snoqualmie River, NE Carnation Farm Road Bridge (Stossel Fill), Novelty Bridge (NE 124th Street), Woodinville-Duvall Road Bridge, and High Bridge (Crescent Lake Road). Bridge dimensions were obtained from as-built drawings and were supplemented with field survey by nhc as necessary. The general approach applied in this study was to characterize the probability of flooding based on an evaluation of annual peak stages rather than annual peak flows. Because of numerous complicating factors the only reliable approach to estimate flood inundation frequency was to apply an unsteady flow hydraulic model (HEC-RAS) to estimate 10-, 2-, 1-, and 0.2-percent-annual- chance (N-year) flood profiles throughout the study reach. The following steps were executed to develop the N-year, unsteady hydraulic models: 1. Reviewed USGS gage records in the Snohomish River basin and selected 16 large historic flood events to model. 2. Developed inflow hydrographs to the unsteady HEC-RAS model for the historic events. These hydrographs utilized available 15-minute and/or hourly USGS flow data, correlation coefficients, rainfall-runoff modeling, and information about reservoir operations on the Tolt and Sultan Rivers. 3. Performed hydraulic modeling of the selected flood events, including calibration/verification to seven of these historic events, and extracted peak stages at 20 key locations throughout the study reach. 4. Estimated plotting positions associated with the 16 selected flood events. 138 5. Manually fit non-parametric frequency curves to the peak stages obtained from step 3 using plotting positions from step 4. 6. Used the curves developed in step 5 to provide estimates of the 10-, 2-, 1-, and 0.2-percent-annual-chance stages at each key location. 7. Developed the N-year HEC-RAS models. Used a trial-and- error method to adjust historic flood inflows so that the peak stage at all key locations match the N-year stage developed in step 6. 8. Applied N-year unsteady HEC-RAS models to estimate the 10-, 2-, 1-, and 0.2-percent-annual-chance profiles throughout the study reach. Channel and overbank roughness factors (Manning’s ―n‖ values) used in the hydraulic computations were chosen using engineering judgment and were based on field observations, orthophotos, and published data. Within the study reach, in-channel roughness values on the Snoqualmie River from 0.03 to 0.055. Overbank roughness values range from 0.02 to 0.15. The hydraulic model was calibrated and verified to high water marks (HWMs) and/or aerial photography from seven recorded events. The Seattle District USACE provided HWMs for the following flood events: January 5, 1969; December 3, 1975; December 26, 1980; and November 23, 1986. King County and several long time valley residents provided HWMs for the November 24, 1990 storm. King County also provided oblique aerial photos of the storms on November 24, 1990, November 29, 1995, and February 9, 1996. A significant effort was made to match each of the high water marks through refinement of the model parameters and structure. Calibration efforts included changes to the delineations of overflow reaches, adjustment of roughness and contraction and expansion coefficients, and modifications to model inputs that govern breakout flows. In some cases, the model simulated water surfaces that were higher than reported HWMs for one event while in other events the simulations yielded lower than reported peak water surface elevations. Where conflicting information was found, an effort was made to split the difference, giving more weight to the recent and larger flood events. The final calibration/verification is felt to be adequate given the complexities of the system and the limitations of a one-dimensional hydraulic model. In general, the estimated 1-percent-annual-chance floodplain limits 139 within the Snoqualmie Valley extend from the west valley wall to the east valley wall. There are two exceptions to this generalization. The first occurs in the reach between Snoqualmie Falls and Fall City, where the Snoqualmie River channel slope is its steepest and the mapped floodplain does not extend all the way to the east valley wall. The second exception is in the vicinity of Carnation, where the Tolt River alluvial fan has raised the valley topography and Snoqualmie River flood waters do not reach the east valley wall. The flattest portion of the flood profile on the lower Snoqualmie River occurs between the High Bridge (Crescent Lake Road) and the Woodinville-Duvall Road Bridge. The 1-percent-annual-chance water surface rises less than 2 feet across this span of 7 RM. All flood insurance studies are referenced to a specific vertical datum. The vertical datum provides a starting point against which flood, ground, and structure elevations can be referenced and compared. Until recently, the standard vertical datum used for newly created or revised studies was the National Geodetic Vertical Datum of 1929 (NGVD 29). With the finalization of the North American Vertical Datum of 1988 (NAVD 88), most studies are being prepared using NAVD 88 as the referenced vertical datum. The hydraulic analysis for the Snoqualmie River was conducted using the NAVD 88 vertical datum. Elevation conversion factors between the two vertical datums vary by location and can be obtained from the National Geodetic Survey’s VERTCON utility (Reference 133). Refer to section 3.3 Vertical Datum for more information. A Regulatory Floodway was delineated for the Lower Snoqualmie River using the unsteady HEC-RAS model and following the FEMA Guidelines and Specifications for Flood Hazard Mapping Partners. The hydraulic model for the baseline floodplain included eight distinct secondary flow branches in addition to the main channel reaches on the Snoqualmie River. These secondary flow branches were added to improve the model’s simulation of complex floodplain hydraulic conditions including breakout flows, topographic divides, overflow channels, and storage areas. For the floodway analysis, the baseline model was modified to reflect floodplain encroachments as could be made while maintaining a flow corridor that could pass the 1-percent-annual-chance exceedence event without exceeding a 1.0 foot surcharge at any point in the main channel. The process of developing the floodway model comprised the following steps: 140 1. Begin with the 1-percent-annual-chance exceedence event (base flood) floodplain model. 2. Transfer the floodway limits from the effective FIS to the new hydraulic model. 3. Evaluate the surcharge of the effective floodway encroachments on water surface elevations in the new model. Like the base flood model, the floodway model is run using unsteady HEC-RAS. Thus the surcharge reflects both a loss of conveyance capacity and a reduction in flood storage. 4. Make adjustments to the effective floodplain encroachments to the extent necessary to pass the base flood without exceeding a 1-foot surcharge at any point in the main channel. To the extent possible, encroachment adjustments were made to provide an equal conveyance reduction on the left and right overbanks. 5. The modeled floodway encroachments at each cross section were plotted on the project work maps and floodway encroachments were adjusted to provide a smooth transitioning floodway delineation and to account for any areas of high ground between model cross sections. 6. The adjusted floodway encroachments from Step 5 were then reinserted in the HEC-RAS model and final floodway simulations were conducted to ensure that the surcharge criteria for the main channel were achieved. As noted, the floodway analysis conducted by nhc focused on achieving a 1-foot surcharge in the main channel. It should be noted that there are areas where the newly estimated Base Flood Elevations (BFEs) in the overbank are not at the same level as the newly estimated main channel BFEs on the adjacent reach. This is because discharge to overflow reaches is affected by hydraulic controls in the floodplain, such as roads or high ground. Comparing the base flood elevations for the main channel with the BFEs in the adjacent overflow reaches shows that elevation differences of greater than 1 foot occur in several locations, including along the overflow branch north of Carnation, and the overflow branch east of Fall City. In these locations, and throughout the study area, the analysis focused on maintaining floodway surcharges in the main channel within the allowable 1- foot limit. The extents of the floodway were extracted from the final floodway model at each modeled cross section. Between sections, 141 the floodway boundary was interpolated based on topographic information and to reflect general hydraulic principles. 3.2.8.1 Springbrook Creek - Springbrook Creek was modeled using the one-dimensional unsteady flow computer program Full Equations (FEQ) developed by Delbert Franz. FEQ simulates the complex hydraulics of the Springbrook Creek system by solving the full energy equation plus continuity integrated in both time and distance along the channel. The program separates flow into two broad classes: (1) stream reaches (branches), (2) level-pool reservoirs. These two parts are then combined using different control structures, such as junctions, bridges, culverts, weirs and others. The hydraulic characteristics of branches, level-pool reservoirs, and control structures are stored in function tables. The function tables are generally computed by using FEQUTL. FEQUTL is a utility program that aids in developing input into FEQ. The FEQ model was developed referencing NGVD 1929 vertical datum. The City’s recent topographic mapping (1999) is in NAVD 1988 vertical datum. The floodplain mapping done as part of this study is all in NAVD 1988 vertical datum. Because it would require extensive effort to change the datum in the original FEQ model, it was decided to continue all hydraulic modeling in NGVD 1929 and use a datum conversion for the floodplain mapping. To convert elevations to NAVD 1988 vertical datum, 3.54 feet must be added. Refer to Section 3.3, Vertical Datum, for more information. The model was originally developed in 1996, but was updated in 2000 and 2001 to account for changes in infrastructure and to include newly surveyed cross sections between SW 16th Street and 27th Avenue SW. These changes are documented in Springbrook Creek Channel and Habitat Improvement Project Technical Memorandum Hydraulic Analysis and Springbrook Creek Channel and Habitat Improvement Project Technical Memorandum Hydraulic Analysis – Supplemental. In addition to the updates in 2000 and 2001, the model was updated to reflect another recent improvement. This improvement included the removal of a berm between two wetlands that were previously connected by a culvert. Due to the two possible operation scenarios at the Black River Pumping Station (BRPS), two different simulation scenarios were developed for the 2-, and 1-percent-annual-chance events. One of 142 the scenarios, referred to as the conveyance scenario, reflects a severe local event without BRPS pumping restrictions. This simulation assesses the conveyance capacity of Springbrook Creek. The other scenario, referred to as the storage scenario, reflects a severe Green River flood that causes the pump station to restrict its pumping rate. The storage scenario assesses the BRPS forebays as well as Springbrook Creek’s and its associated wetlands’ ability to temporarily contain the flood waters when the pump station discharge capacity is restricted. The higher of the resulting water levels for the two scenarios was used to determine the flood profile for the various frequency events. Only the conveyance scenario was used for the 10-percent-annual- chance event. The storage scenario was not a concern because it was determined via frequency analyses of peak annual storage volumes in the BRPS forebay that this event would create only a negligible build-up of storage in the forebay during high Green River flows. As noted above, the hydraulic model was originally developed in 1996. Cross-section data in the model came from a variety of sources including field survey by NRCS (formerly SCS) in 1990, more recent survey by W&H Pacific and R.W. Beck, channel design drawings, and 1980 USACE topography. It is understood that many of the data sources (i.e., cross sections) were not ―as- built‖. In order to confirm that cross sections used in the model generally agree with the existing channel conditions, a validation or comparison was performed. Six channel cross sections were surveyed and compared to the cross sections used in the FEQ model in order to confirm use of the cross sections in the model is reasonable. It was recognized that some differences between the modeled cross section and new surveyed cross sections would be likely. However, upon comparing the newly surveyed cross sections and the cross section used in the 1996 model, the extent of the differences, particularly downstream of SW 16th Street is fairly significant. Due to the differences in the surveyed and modeled cross section downstream of SW 16th Street, a sensitivity analysis was performed using an existing HEC-RAS model of the area which uses the same cross sections as the FEQ model. The sensitivity analysis was performed to see if the differences in the cross sections had a significant effect on the water surface profiles. The results of the sensitivity analysis showed that using the new 143 surveyed cross sections increased water surface elevations by more than 1 foot in some locations. The higher elevation continued upstream, although the increase in elevation decreases as you move upstream. This difference in simulated water levels is greater than the desirable accuracy of the modeling and therefore a new survey was conducted in between the upstream end of the forebay to SW 16th Street and the newly surveyed cross sections were used to modify the FEQ model for this floodplain mapping study. Several of the Springbrook Creek valley wetlands were modeled as part of the Springbrook Creek channel. Other wetlands were modeled as level pool reservoirs because they are separated from the creek, but are connected via a pipe system or by overbank flow conditions during high flows. The storage data (stage-area relationship) for the wetlands modeled as level pool reservoirs was based on 1980 Corps of Engineers topographic mapping. The north series of ponds is connected to Springbrook Creek with a flap gate to reduce the potential for Springbrook Creek flows to back up into the pond system. For the determination of the floodplain, it was assumed that the water levels in these ponds would match the base flood elevation of Springbrook Creek where they connect to the creek. The floodway boundary developed in this study was determined by modeling scenarios that included filling in the floodplain (overbank areas on both sides of the channel and wetland areas) such that it causes no more than a 1-foot rise in the water surface profile. The floodway as established by the existing FIRM was used as an initial trail floodway for this study. The result was that simulated water surface elevations along the creek were well above the 1-foot rise threshold. The hydraulic analysis used the flood events identified by the hydrologic analysis to analyze the Springbrook Creek system. An unsteady flow model was used to determine the base flood profile and the floodplain and floodway delineation. An unsteady flow model can simulate flood routing on the creek system more accurately than a steady state model because it accounts for the attenuation that occurs due to storage in the system. The Springbrook Creek system has a significant amount of storage due to adjacent wetlands, so using a model that has the ability to attenuate the peak flow through this storage was important in order to provide an accurate assessment of the water surface elevations along the creek. The hydraulic analysis was conducted using flow events as defined in HASC. 144 The water surface elevations in the study reach are impacted by flood flows, storage capacity of the adjacent wetlands, the conveyance capacity of the multiple culverts and bridges and the operation of the BRPS. The operation of the BRPS depends on the flow in the Green River. An unsteady (hydrodynamic) hydraulic modeling was used to characterize water surface profiles in Springbrook Creek in order to account for dynamic flood storage in study reach wetlands and, more significantly, to accurately simulate flood discharges from Springbrook Creek to the Green River via the BRPS. Pump Station operations, including limitations on pumped discharges when the Green River flows are high, impose a dynamic downstream boundary condition of the Springbrook Creek drainage system. 3.2.8.2 Green River (lower Green River) - A steady-state HEC- RAS computer model was created to simulate the hydraulic characteristics of the study reach under the condition that all levees remained in place (i.e. the current channel geometry). The model was used to compute water surface profiles corresponding to the 10-, 2-, 1-, and 0.2-percent-annual-chance floods, in-channel flood inundation limits for the 1-percent-annual-chance (base flood) and 0.2-percent-annual-chance events, and floodway data for the in- channel portion of the floodway and several isolated levee failure scenarios. A second numerical hydraulic model was developed using FLO-2D to simulate the effects of complex levee failure scenarios through the leveed portion of study reach (RM 10.6 to RM 29.7) and to define the floodplain limits and floodway path through the overbank areas. The following sections provide detailed descriptions of the development and application of the hydraulic models used in this study. HEC-RAS Channel and Topography Two hundred and twenty-three cross sections are used in the HEC- RAS model to represent the channel and bank geometry along the Lower Green River. The in-water portions of most of these cross sections were surveyed by Minister-Glaeser Surveying (MGS) in February 2006 with additional survey work taking place in early 2007. The in-channel cross section surveys typically only included the stream channel from edge of water to edge of water. The levee slopes and channel banks were not field surveyed; therefore, the upland portion of each cross section was added using the digital topographic data developed for this study by 3DI- West. The topographic data was created using photogrammetric techniques based on aerial photographs of the study reach that were taken on 145 February 19, 2006. Feature data, including buildings, vegetation, hydrography, and road surfaces, were added to the topographic data to finalize the base mapping in January 2008. HEC-RAS Hydraulic Structures Thirty-six bridges crossing the Lower Green River within the study reach were coded into the HECRAS model. Detailed information on some of the bridges was obtained from the effective FIS study model. However, most of the bridges were either newer than the effective study or simply not included in the effective model. Data for these structures were obtained from as-built drawings of the bridges and limited field surveys by nhc in December 2006. All bridge data were field verified to the extent possible by nhc. HEC-RAS Starting Water Surface Elevation The hydraulic model extends to the downstream study limit at RM 3.85. For calibration runs the starting water surface at the downstream end of the model was set equal to the observed tidal water surface elevation at the NOAA Seattle Station (No. 9447130) coincident with the peak of the simulated flood. For the flood profile simulations, the starting water surface elevation was set equal to the mean high water level at the Seattle station. It should be noted that the starting water surface used in the model has very little effect on simulated water surface elevations upstream of about RM 12.0 (e.g. lowering the starting water surface by 9 feet drops the BFE at RM 12 by about 0.08 feet). HEC-RAS Model Calibration Initial channel and overbank roughness factors (Manning's "n" values) used in the hydraulic computations were taken from the effective FIS model. These values were then adjusted by calibration to four observed flood events and one low flow event. High water mark data were collected by nhc and MGS for the high flow events of January 7, 2006, November 11, 2006, and March 25, 2007. High water mark data were also obtained from King County and other sources for the February 8-9, 1996 flood event. Water level observations are available for 22 locations in the Lower Green Study reach during the January 2006 flood event. Corresponding high water mark data are also available for five of these locations. The January event had an estimated peak discharge of 11,200 cfs at the USGS gage near Auburn. Nine high water marks are available for the November 2006 flood and 11 were 146 recovered for the March 2007 flood event. The November event had an estimated peak discharge at the Auburn gage of 12,200 cfs while the estimated peak discharge for the March 2007 event was 8,500 cfs. For the February 1996 event, nhc had HWM information at two locations, the Black River Pump Station Discharge Channel and the USGS gage at Auburn. In addition, approximate HWM information was extracted from oblique aerial photographs taken by King County near, or slightly after, the peak of this event. In all, 20 HWMs were identified on the photographs with elevations estimated from the topographic data created for this study by 3DI - West. In addition to calibration to the high flow events, the model was also calibrated to the water surface elevation observed at the time of the aerial flight on February 19, 2006. The flow was about 1,100 cfs at the Auburn gage. The final calibrated "n" values for the Lower Green River channel ranged from 0.026 at the upstream end of the study reach to 0.047 in the reach near the Horseshoe Acres pump station in Kent (RM 24.26 - 28.21). In general, Manning's "n" values downstream of RM 29 ranged from 0.039 to 0.047. These in-channel roughness values account for both the heavily vegetated channel banks as well as the main channel bed. An attempt was made to define separate "n" values for the banks and bed but the composite "n" value computation that is used in HEC- RAS whenever multiple "n" values are defined between the bank stations results in unreasonable values for the Lower Green River. Thus, manually estimated composite "n" values were used for the channel. Overbank "n" values used in the HEC-RAS model range from:  0.02 for roadways and other paved surfaces  0.04 to 0.055 for turf grass or pastured agricultural areas  0.07 to 0.09 for areas of thick brush or other dense vegetation. The model was calibrated to reproduce observed stages for each of the calibration events as closely as possible, while bearing in mind that the most important event for Flood Insurance Study purposes is the 1-percent-annual-chance event and thus calibration to the highest observed discharges is more valuable than to the lower flow events. High water marks were generally matched to within 0.5 feet although in a few instances the difference between simulated and observed water levels was as great as 1 foot. 147 FLO-2D Model Development Simulation of the complex floodplain hydraulics under the levee failure scenarios is not feasible with the HEC- RAS 1- Dimensional model. Therefore, a FLO - 2D model was developed for the floodplain and channel between RM 29.7 (near the Auburn Golf Course) and RM 10.6 (just downstream of the Black River Pump Station). The extents of the FLO-2D model are, compiled on February 12, 2008, was used in this study. A grid size of 180 feet was selected, resulting in a model domain of approximately 21,000 cells. Grid cell elevations were calculated by averaging elevations of a l0-foot resolution DEM produced from the 3DI- West TIN. Prior to averaging, areas of fill such as roadway embankments that would be modeled as levees were removed from the DEM to avoid biasing elevation values upwards. River bank grid cell elevations were set equal to the natural bank elevations to ensure accurate bank overflow rates in the levee failure simulations. Mill Creek, Mullen Slough and lower Springbrook Creek were simulated by setting the elevations of individual grid cells to approximate channel thalweg elevations, and adding width reduction factors as necessary to match actual channel widths. Area reduction factors (ARFs) are used in FLO-2D to handle reductions in flood storage within cells (e.g. due to buildings). These ARFs were calculated on an individual grid cell basis by setting the ARF value to the percent of the cell covered by structures as seen in the feature data coverage developed for the topographic base mapping. Width reduction factors (WRFs) are used to account for conveyance loss caused by structures obstructing the flow paths FLO-2D computes in each of the eight primary compass directions (i.e. N, NE, E, SE, etc.). WRFs were calculated by subdividing each model cell into a 3x3 sub-grid (9 sub-grid cells of 60 feet by 60 feet) and determining the percent of the area covered by structures within each sub-grid cell. The WRF for each flow path direction was then set to the larger of the covered area percentages for the pair of sub-grid cells that defined that particular flow path. FLO-2D channel cross sections were generated by first using the interpolation tool in HEC-RAS to produce a cross section corresponding to each grid cell along the channel alignment. These cross sections were then clipped vertically at the natural bank elevations, which were determined on a cell by cell basis by taking the average elevation along a profile line delineated in GIS just 148 outside the outer toe of the levee or on the top of the natural bank. Levees along the Green River, railroads, and roadways on fill were coded as levees in the model. Levee crest elevations were taken from the topographic mapping. The FLO-2D model's downstream boundary condition was set as a rating curve generated by running a series of flows through the HEC-RAS model and fitting a best-fit power function though the resultant stage-discharge points. Three hydraulic structures were incorporated in the model using rating tables: the Mill Creek (Auburn) culvert at SR-167, the lowest Mill Creek (Kent) bridge at the BNSF Railroad and the Black River Pump Station. A rating table for the SR-167 culvert was generated from an existing nhc FEQ model of Mill Creek. Preliminary modeling of floodway alternatives revealed that the Mill Creek (Kent) bridge opening under the railway tracks just upstream of its confluence with Springbrook Creek is a critical control on water levels over a large area upstream. Therefore, this opening was simulated using a rating table generated using the Springbrook Creek HEC-RAS model, which has far greater detail on the multiple bridges, culverts and channel cross sections that control the rating at this location. As discussed above, the Black River Pump Station was simulated using the nominal pump rating curve, with the contribution of local interior drainage flows (the 9- day, 1-percent-annual-chance flow) subtracted from the capacity. It should be noted that most of the bridges over the Green River within the study reach have clear spans, do not experience pressure flow, have their abutments behind the river levees, and present little or no constriction to flow. The water surface profiles in the HEC-RAS model and observed high water marks confirm this, showing no significant backwater effects at bridges. Therefore the bridges were not explicitly included in the FLO-2D model. The reasoning behind this decision is discussed in detail below. In the HEC-RAS model, the bridges were all modeled in the ―low flow-energy‖ mode which converts bridges to standard step- backwater cross sections. In the FLO-2D model, the upstream face cross section of each bridge in the HEC-RAS model was extracted for use as the cross section for the grid cell containing that bridge. The result is that the two models use similar approaches for bridges using only cross sectional data tables in the solution of the hydraulic equations. The only difference between the models is in the numbers of cross sections at each bridge (4 for HEC-RAS versus 1 for FLO-2D), and in the basic solution algorithm, with HEC-RAS using steady state step backwater methods and FLO-2D 149 using an explicit unsteady flow solver. Special rating tables are not used for bridges in either model. Discussions with FLO-2D developer Dr. Jim O’Brien and USACE staff on another NHC project (Skagit River) revealed that inclusion of bridge rating tables in FLO-2D was a common problem, and the tables typically needed modification from the HEC-RAS outputs to calibrate correctly, even where the bridge was not hydraulically significant. Given the number of bridges in the Green River system, that the bridges are hydraulically insignificant, that adding rating tables for every bridge promised to add significant stability and calibration complexities to the model, and that the FLO-2D and HEC-RAS models treated bridges in a similar way, it was decided that the selected modeling approach for the Green River bridges was appropriate. FLO-2D Model Calibration The FLO-2D Model was calibrated to the February 8-9, 1996 flood event. High water marks from the November 2006 event (with a peak flow at the Auburn gage of only 200 cfs less than the Feb 1996 event) showed a very similar profile above RM 18 and were also used to guide and validate the model calibration. Downstream of RM 18, the observed high water mark profiles for the 2 events diverge, and greater weight was given in the calibration to the higher February 1996 HWMs. The average absolute error of the calibrated profile to the 18 high water marks from the February 1996 event was 0.37 ft, and the largest error was -0.86 ft. Calibrated in-channel Manning's "n" values ranged from 0.035 to 0.045, except at the Auburn Mill Creek and Mullen Slough confluences, where single cell values of 0.050 were used to dampen transient surges in the solution. Calibration of the model in the floodplain areas is not possible because the areas protected by levees have not experienced flooding during any of the recent high flow events. Therefore, Manning's "n" values for the floodplain areas were set based on engineering judgment and past experience. The floodplain was delineated into zones of similar roughness based on vegetative and land-use coverage and the FLO-2D model grid cells were attributed accordingly. Floodplain roughness values ranged from 0.04 for open pasture, golf courses and parks, 0.075 for large warehouse industrial areas, 0.08 for dense residential areas, up to a maximum of 0.09 for thickly forested and brushy wetlands. 150 FLO-2D Model Application to Levee Failure Simulations Approximately 30 individual levee elements (facilities) were identified along the Lower Green River study area, primarily from the King County facility inventory. Some of these levee elements did not fully block the flow of water from the riverward side to the landward side of the levee, either because they had openings, e.g. culverts through the levee prism, or they were not high enough to contain the 1-percent-annual-chance event. Mapping of the area behind these levees, therefore, was done by transferring the in- channel BFE to the area behind the levee. The remaining levee elements were then grouped into "failure reaches" based on the landward area that would be inundated if the leveed reach was failed. In other words, all levees and appurtenant structures that protect the same land area are combined into a single levee failure reach. Combining the levee elements resulted in a total of five levee failure scenarios; Reddington, Reddington plus Mill Creek/Mullen Slough, Horseshoe Bend, Midway and Johnson Creek, and the East Valley. The five levee failure scenarios were analyzed individually using FLO-2D. In addition, the "all levees intact" condition, and the "fail all levees" condition were simulated. The floodplain map described below is a composite of the highest simulated water surface elevations at each grid cell from among these simulations. An additional consideration for the levee failure analyses was the model's representation of the Black River Pump Station (BRPS). The currently installed nominal pump capacity of the BRPS is approximately 2,945 cfs (King County, 2007). The flow from the Green River into the East Valley area under the "East Valley" and "Fail-all" levee failure scenarios is about 2,200 cfs at its equilibrium condition. This flow would ultimately need to be pumped back into the Green River via the BRPS. The BRPS must also handle interior drainage for the East Side Green River watershed which is estimated at approximately 350 cfs for the 1- percent-annual-chance, 9-day condition. Based on these considerations, the installed BRPS pump capacity is adequate to handle the simulated pump station inflows without requiring storage of Green River floodwaters at the BRPS. To confirm the pumping capacity of the BRPS and verify routine operational needs, King County conducted a rigorous inspection and maintenance project of the BRPS during 2007 and 2008. During the inspection, all elements of the BRPS system were visually and mechanically tested. In the summer of 2008 as part of necessary 151 maintenance, accumulated sediment was removed from the pump bays (i.e., chambers) of each pump. Subsequent to the sediment removal and with adequate forebay water levels, each pump was operated to ensure its functionality. Historically the BRPS has handled local stormwater runoff using only five of the eight pumps available at the facility. However, as described above, King County has verified that the full installed capacity is operational. In addition, under the newly formed countywide Flood Control Zone District, the County has the financial capability to provide the staff resources for operations and inspections, routine maintenance, and repairs as necessary to ensure the BRPS can continue to operate up to its design capacity. Therefore, under the scenario of an assumed levee failure of the Green River, the County and four valley cities mutually supported using the full pumping capacity (2,945 cfs) in the flood study modeling. The design pumping capacity would be adequate to handle both the interior runoff and the simulated Green River overflows. The FLO-2D model was therefore configured to use the BRPS design capacity (reduced by 350 cfs to account for interior runoff). For the purposes of this flood study, only the certified Tukwila 205 Levee is recognized in the modeling and mapping. All other levees in the Lower Green River are not certified and thus are not recognized as providing flood protection for purposes of this mapping study. The FLO-2D model was used to analyze levee failure scenarios for all levees in the middle reach (between RM 10 and RM 30). The floodplain extents and depths of inundation were simulated for the five levee failure scenarios as described above. A composite floodplain map for the overbank areas was developed showing the worst case flooding from these simulations. The final floodway configuration includes an area along the main channel corresponding to the HECRAS floodway, the Mill Creek off-channel floodway and the split flow floodway path on the right bank near RM 15. Review of the proposed floodway shows that the Mill Creek (Auburn) off-channel floodway was reduced slightly because simulated base flood elevations in this area are slightly lower than those previously mapped. The Springbrook Creek floodway was retained as delineated on the Preliminary DFIRM, with a minor expansion near the SW 41st Street crossing, and used to pass flows which exit the Lower Green River near RM 15 and return to the river via the Black River Pump Station. Validation of the adequacy of the Springbrook Creek floodway was demonstrated by routing flows calculated with the FLO-2D model down Springbrook Creek floodway and verifying that the water surface elevation did not exceed the FLO-2D "fail all" water 152 surface by more than 1 foot at any location. No profiles were generated for overbank areas modeled using the FLO-2D model. However, base flood elevations for these areas were established by manually fitting BFE contours at 1-foot increments to the grid of the maximum simulated water surfaces generated from the FLO- 2D results. Green River (Middle Green River) – A steady-state HEC-RAS computer model was created to simulate the hydraulic characteristics of the study reach. The model was used to compute water surface profiles corresponding to the 10-, 2-, 1-, and 0.2- percent-annual-chance discharge, flood inundation limits for the 1- percent-annual-chance (i.e. base flood) and 0.2-percent-annual- chance events, and the floodway boundary for the 1-percent- annual-chance flood. The following sections provide detailed descriptions of the development and application of the HEC-RAS model for this study. Channel and Floodplain Topography Seventy-three cross sections are used in the HEC-RAS model to represent the channel and floodplain geometry along the study reach. The in-channel portions of most of these cross sections were surveyed by Minister-Glaeser Surveying (MGS) in August and September 2006. Additional cross sections were interpolated from the survey and topographic data where needed. The in- channel cross section surveys typically only included the stream channel from bank to bank. The floodplain was not surveyed; therefore, the overbank portion of each cross section was added using the digital topographic data developed for this study by 3Di- West. The topographic data was created using a photogrammetric techniques based on aerial photographs of the study reach that were taken on February 19, 2006. Hydraulic Structures Six bridges cross the Middle Green River within the study reach. These are located at:  State Highway 18 (two spans) at RM 33.27,  Burlington Northern Railroad Crossing at RM 33.32,  SE Auburn - Black Diamond Road at RM 33.38,  SE Green Valley Road at RM 34.62, 153  218th Avenue SE (Whitney Bridge) at RM 41.20, and  SE Flaming Geyser Road at RM 42.54 Detailed information on the bridges was obtained from an earlier floodplain mapping study performed for King County by Harper Houf Righellis, Inc. (HHR, 1995). These data were field verified to the extent possible by nhc and additional data were collected as necessary in March 2007. Starting Water Surface Elevation The hydraulic model was extended downstream to include the Lower Green River Study reach to provide the downstream starting water surface elevation. This approach ensures that the hydraulic effects of the large logjam near RM 32.3 were reflected in the modeling. The cross section and topographic data collected in 2006, provided the most reasonable and representative approach for establishing starting downstream water surface elevations. It is not anticipated that future refinements in the downstream HEC- RAS model will have any significant effect on water surface elevations at the SR-18 Bridge. Model Calibration Initial channel and overbank roughness factors (Manning’s ―n‖ values) used in the hydraulic computations were selected using engineering judgment and were based on field observations, orthophotos, published data, and values used in the previous flood studies. These values were then adjusted by calibration to three observed flood events and one low flow event. High water mark data were collected by nhc and MGS for the high flow events of January 7, 2006, November 11, 2006, and March 25, 2007. High water mark data are available for seven locations in the study reach for the January 2006 flood event which had estimated peak discharges ranging from 9,480 cfs at the upstream end of the study to 11,070 cfs at the downstream end. Two high water marks were available for each of the November 2006 and March 2007 flood events. The November event had estimated peak discharges ranging from 10,250 to 12,170 cfs while the estimated peak discharges for the March 2007 event ranged from 8,070 to 8,730 cfs. In addition to calibration to these high flow events, the model was also calibrated to the water surface elevation observed at the time of the aerial flight on February 19, 2006. The flow at this time ranged from 730 cfs at the upstream end of the study reach to 1,100 cfs at the downstream end. 154 The final calibrated ―n‖ values for the main channel range from 0.026 at the downstream end of the study reach to 0.045 in the reach through Flaming Geyser State Park. Overbank ―n‖ values range from:  0.02 for roadways and other paved surfaces  0.04 to 0.055 for turf grass or pastured agricultural areas  0.07 to 0.09 for areas of thick brush or other dense vegetation. The model was calibrated to reproduce observed stages for all calibration events as closely as possible, while bearing in mind that the focus of the model is for the 1-percent-annual-chance event. High water marks were generally matched to within 0.25 feet, although in some cases the difference between simulated and observed water levels was as great as 0.5 feet. Floodplain Discussion Within the limits of this floodplain mapping study, the Middle Green River can be divided into two general reaches. The upstream reach, from River Mile 44.3 to about RM 39 is relatively steep with a single thread and relatively straight channel and a floodplain that is generally confined to the main channel at most locations. Downstream of RM 39 to the downstream study limit at RM 33.25, the channel has a lower gradient, includes several large meander bends, and the floodplain is much wider than the channel and often covers the valley from side wall to side wall. The width of the floodplain in the upper reach is generally 200 feet to 500 feet wide. The floodplain in the lower reach ranges up to 2,500 feet wide or wider. Overbank inundations in the lower reach range from a few feet, near the transition between the upper and lower reach, to 6 feet or more near the downstream end of the study near RM 34.5 Table 4, ―Manning’s ―n‖ Values,‖ Table 6 (located in Volume 2 of the FIS), ―Floodway Data,‖ and the Flood Profiles were revised to reflect the results of the study. 3.2.9 Revision 9 Sammamish River and White River - A steady-state HEC-RAS, Version 4.0, computer model (Reference 188) was developed to stimulate the hydraulic characteristics of the White River. The HEC-RAS model was used to compute water surface profiles corresponding to the estimated 10-, 2-, 1-, and 0.2-percent-annual- 155 chance floods, map flood inundation limits for the 1-percent- annual-chance (i.e. based flood) and 0.2-percent-annual-chance events, and define the floodway boundary for the 1-percent- annual-chance flood. Channel and Floodplain Topography One hundred and seventeen surveyed cross-sections were used in the Sammamish River model geometry. The in-channel portions of these cross-sections were surveyed by Pacific Geomatic Services, Inc. (PGS) in April 2009. The bathymetric surveys for the cross-sections included the river channel from the bottom of the channel to just above the water surface elevation at the time of the surveys; the overbank portion of each cross-section was obtained from the digital topographic data developed for this study by 3Di-West. This topographic data was created using photogrammetric techniques based on aerial photographs taken in March 2009. Two-foot contour topographic maps at a map scale of 1 inch equals 200 feet were developed for this study. Thirty-eight cross sections are used in the White River model. The in-channel portions of most of these cross-sections were surveyed by Minister-Glaeser Surveying (MGS) in April and May 2007. Additional cross-sections were interpolated from the survey and topographic data where needed. The surveys for the most of the cross-sections only included the river channel from bank to bank. Where the floodplain was not surveyed, the overbank portion of each cross-section was added using the digital topographic data developed for this study by 3Di-West. The topographic data was created using photogrammetric techniques based on aerial photographs that were taken on March 29, 2007. Two-foot contour topographic maps at a map scale of 1 inch equals 200 feet were developed. The cross-section information sources included ―Field Survey‖ indicating the channel was directly surveyed in the field by MGS or NHC, ―Topographic Map‖ meaning the channel or floodplain geometry was extracted from the topographic contours and ―Interpolated‖ signifying the cross-section was interpolated from the upstream and downstream sections in the HEC-RAS model. Hydraulic Structures Hydraulic structures in the Sammamish River include numerous bridges with piers and/or abutments located throughout the river and the weir at RM 13.3. Detailed information on these structures 156 was obtained from various state and local agencies, including Washington Department of Transportation, the City of Bothell, and the City of Redmond. These data were field verified to the extent possible by PGS in March 2009 and NHC in October 2009. Hydraulic structures include the State Highway 410 Bridge at RM 22.45 and the White River Hydro Project diversion weir at RM 23.6. Detailed information on these structures was obtained from various state and local agencies, including Washington Department of Transportation, King County, the USACE, and Puget Sound Energy. These data were field verified to the extent possible by NHC in March 2008. Starting Water Surface Elevations Lake Washington stage, recorded at the Hiram M. Chittenden Locks, was used as the downstream boundary condition for the 60- year unsteady flow simulation period. Observed data were available only back to 1991 so a constant stage of 16.5 feet (NAVD 88) was used prior to that date for the unsteady HEC-RAS simulations. The stage of 16.5 feet (NAVD 88) corresponds with winter lake stages when peak flows typically occur on the Sammamish River. The observed stage at the Locks was converted to NAVD 88 using the following: NAVD 88 = USACE Lake Washington Datum – 6.82 feet (conversion to NGVD 29) + 3.6 feet (conversion to NAVD 88) +0.25 feet (to account for the average increase in lake stage between the Locks and Kenmore, (Reference 187). The steady state modeling required a constant tailwater elevation. For the steady state HEC-RAS modeling, a tailwater condition of 18.5 feet (NAVD 88) was used corresponding to the maximum normal operating level of the Lake (the annual variation in lake stage is between 16.5 and 18.5 feet (NAVD 88). By using the annual maximum instead of the typical winter stage used in the unsteady analysis (16.5 feet NAVD 88), the resulting 1-percent- annual-chance event hydraulic and mapping results in a stage near the typical summer time river stage (instead of below it) near the downstream end of river. The significance of choosing the higher, but summer time, water level in Lake Washington was investigated by a sensitivity analysis. The sensitivity analysis varies the downstream boundary condition over the range of observed flows 16.5 to 18.5 feet (NAVD 88) and showed that there is relatively small change in upstream river stage. For the 1-percent-annual- chance event, there is less than 0.7 feet difference at the 68th Avenue Northeast Bridge (1,900 feet upstream) and less than 0.2 157 feet at the 96th Avenue Northeast Bridge when specifying the two different boundary conditions. The starting water surface elevation for the HEC-RAS hydraulic model was obtained using a normal depth approximation, with a slope set to a value of 0.0072 ft. Model Calibration Initial channel and overbank roughness factors (Manning’s ―n‖ values) used in the hydraulic model were selected based on field observations, orthophotos, published data, values used in the previous FISs, and engineering judgment. The model was calibrated to high water marks along the length of the river and stage and flow hydrographs, when available, at the Willows Run gage and at the weir for three observed flood events (Reference 189). The Willows Run gage (King County gage 51t/USGS gage 12125200) has observed data from 1965 to 2009, and the weir (King County gage 51m) from 2001 to 2009. High water marks were generally matched to within 0.25 feet, but all values were within 0.5 feet. Manning’s ―n‖ values were varied for these events to reflect the increase in bank vegetation growth over time. The January 2009 calibration, representing current conditions, was used for the 60-year simulation and final analysis of the 10-, 2-, 1-, and 0.2-percent-annual-chance events and floodway. The final calibrated ―n‖ values for the channel ranged from 0.035 to 0.06 for the January 2009 event. The final calibrated ―n‖ value for the overbanks ranged from 0.03 to 0.15 as listed below High water mark data were collected by NHC and MGS for the high flow event of January 11-12, 2006. High water marks were available at six locations for the January 2006 event. The corresponding flows estimated for these marks ranged from 6,090 cfs at the upstream end on January 12th, to an event peak discharge of 10,750 cfs at the downstream end. High water mark data were available for the flood event in November 2006 at the two USGS gaging stations in the reach (No. 12098500 and No. 12099200). The USGS estimated peak discharge at the downstream gage, above the confluence of Boise Creek, was 14,700 cfs. A single high water mark was available for the December 2007 event. The discharge corresponding to that mark was estimated at 6,830 cfs. 158 With and Without Levees Modeling FEMA requires a ―without levee‖ analysis be conducted for the 1- and 0.2-percent-annual-chance event flows when non-certified levees are present. This is done in addition to a simulation that allows the ―levees‖ to hold back water. The higher water surface elevations between the ―with levee‖ and ―without levee‖ simulations are then mapped. Berms along the Sammamish River banks, acting like ―levees,‖ obstruct water from getting into the floodplain. These berms are not certified as levees. Therefore, to meet FEMA requirement, the hydraulic analysis for this study assumes that these berms do not hold back water. This affects the extents of inundated area for the 1-and 0.2-percent-annual-chance events. The floodway analysis (Section 4.2) assumes that the berms do not provide flood protection. Floodplain Discussion The Sammamish River can be divided into two general reaches of differing characteristics. The upstream reach, from Lake Sammamish down to approximately RM 6.2, has a wide valley relative to the lower section and a flat valley floor. Broad overbanks are exposed to potential inundation. Distances from valley wall to valley wall in some areas are upwards of 4,500 feet. Downstream of RM 6.2, the valley narrows considerably, with 1,000 feet or less between valley walls. The channel is also more sinuous in the downstream reach. White River can be divided into 2 general reaches of differing characteristics. The upstream reach, from Mud Mountain Dam at RM 28.6 to about RM 27.0 is very steep and is confined within a canyon with steep sidewalls. The river has a single thread and the floodplain is generally limited to the area between the channel banks. The width of the floodplain in this upper reach is generally 100 feet to 250 feet. Downstream of RM 27 to the downstream study limit at RM 22.01, the channel has a slightly lower gradient and includes several large meander bends and side channels. The floodplain in the lower reach is often much wider than the channel and in some locations extends from valley wall to valley wall. The floodplain in the lower reach ranges from several hundred up to 1,600 feet wide. Overbank inundation in the lower reach of the studied area ranges from a few feet to 6 feet or more in the low lying side channels where flow splits occur. The Manning’s ―n‖ values for all detailed studied streams are presented in Table 4. Table 4. Manning’s “n” Values Stream Channel "n" Range Overbank "n" Range Bear Creek 0.040-0.100 0.060-0.300 Big Soos Creek 0.024-0.090 0.040-0.150 Black River 0.011-0.050 0.050-0.150 Cedar River 0.02 - 0.045 0.03 - 0.15 Coal Creek 0.035-0.042 0.055-0.075 Des Moines Creek 0.030-0.040 0.050-0.100 East Branch of West Tributary Kelsey Creek 0.035-0.042 0.055-0.075 East Fork Issaquah Creek 0.035-0.060 0.050-0.250 Evans Creek 0.039-0.063 0.056-0.135 Forbes Creek 0.045 0.050 Gardiner Creek 0.070-0.080 0.070-0.200 Gilman Boulevard Overflow 0.040-0.045 0.030-0.045 Green River 0.020-0.055 0.060-0.300 Holder Creek 0.030-0.055 0.020-0.120 Issaquah Creek 0.030-0.088 0.035-0.300 Kelsey Creek 0.035-0.042 0.055-0.075 Little Bear Creek 0.012-0.080 0.016-0.150 Longfellow Creek 0.025-0.065 0.065-0.070 Lyon Creek 0.025 0.050 Maloney Creek 0.037-0.055 0.050-0.100 May Creek 0.030-0.090 0.055-0.150 May Creek Tributary 0.040 0.070 McAleer Creek 0.025-0.050 0.013-0.080 Mercer Creek 0.035-0.042 0.055-0.075 Meydenbauer Creek 0.035-0.042 0.055-0.075 Middle Fork Snoqualmie River Overflow Channels 0.040-0.045 0.075 Mill Creek (Auburn) 0.012-0.090 0.045-0.095 Mill Creek (Kent) 0.012-0.041 0.050-0.120 Miller Creek 0.040-0.050 0.060-0.120 North Branch Mercer Creek 0.035-0.042 0.055-0.075 North Creek 0.030-0.055 0.050-0.100 North Fork Issaquah Creek 0.026-0.055 0.070-0.120 North Fork Meydenbauer Creek 0.035-0.042 0.055-0.075 Table 4. Manning’s “n” Values (Continued) Stream Channel "n" Range Overbank "n" Range North Fork Thornton Creek 0.012-0.045 0.028-0.120 Patterson Creek 0.040-0.120 0.020-0.080 Raging River 0.035-0.080 0.050-0.090 Ribary Creek 0.045-0.048 0.050-0.120 Richards Creek 0.035-0.042 0.055-0.075 Richards Creek East Tributary 0.035-0.042 0.055-0.075 Richards Creek West Tributary 0.035-0.042 0.055-0.075 Right Channel Mercer Creek 0.035-0.042 0.055-0.075 Rolling Hills Creek 0.025-0.040 0.020-0.060 Sammamish River 0.026-0.057 0.027-0.042 Snoqualmie River (Mainstem) 0.030-0.055 0.020-0.150 Snoqualmie River (Middle and North Forks) 0.028-0.058 0.040-0.170 South Fork Skykomish River 0.038-0.048 0.080-0.120 South Fork Snoqualmie River 0.038-0.100 0.070-0.120 South Fork Thornton Creek 0.012-0.045 0.028-0.120 Springbrook Creek 0.050-0.070 0.030-0.040 Swamp Creek 0.045-0.085 0.050-0.120 Thornton Creek 0.012-0.045 0.028-0.120 Tibbetts Creek 0.027-0.055 0.080-0.130 Tolt River 0.042-0.055 0.070-0.100 Vasa Creek 0.035-0.042 0.055-0.075 Walker Creek 0.050 0.060-0.120 West Fork Issaquah Creek 0.024-0.050 0.035-0.120 West Tributary Kelsey Creek 0.035-0.042 0.055-0.075 White River 0.027-0.057 0.015-0.99 Yarrow Creek 0.045 0.150 Appendix D – Supplemental Material Specification Structural Soil-Bearing Fabric Specification