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coterra 321 3rd Avenue South, Suite 406 Seattle, Washington 98104 [PHONE REDACTED] NE 90th STREET OUTFALL BASIN ANALYSIS Project: Redmond Integrated Service Center 15511 NE 90th Street Redmond, WA 98052 Prepared For: Third Place Design CO-OP 117 Wester Ave W, Suite 266 Seattle, WA 98119 Prepared By: Max Berde, PE Reviewed By: Peter Apostol, PE Date: October 20, 2016 ENGINEERING PLLC ATTACHMENT Q ---PAGE BREAK--- “I hereby certify that this Basin Analysis for the Redmond Integrated Service Center Redevelopment Project has been prepared by me or under my supervision and meets minimum standards of City of Redmond and normal standards of engineering practice. I hereby acknowledge and agree that the jurisdiction does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities designed by me.” ATTACHMENT Q ---PAGE BREAK--- TABLE OF CONTENTS Section No. Subject SECTION I PROJECT OVERVIEW SECTION II EXISTING SECTION III ANALYSIS SECTION IV UNIFORM FLOW SECTION V COMPARISION TO EXISTING SECTION VI COMPARISION TO FULL ONSITE SECTION VII PROPOSED SECTION VIII LIST OF FIGURES FIGURE 1 VICINITY FIGURE 2 NE 90TH STREET OUTFALL BASIN MAP LIST OF APPENDICES APPENDIX A SAMMAMISH RIVER FEMA FLOOD PROFILES APPENDIX B SUB-BASIN FLOWS APPENDIX C PROPOSED CONDITION BACKWATER ANALYSIS APPENDIX D PROPOSED SITE UNIFORM FLOW ANALYSIS APPENDIX E EXISTING CONDITION BACKWATER & FLOW ANALYSIS APPENDIX F FULL ONSITE DETENTION BACKWATER & FLOW ANALYSIS APPENDIX G AS-BUILT PLANS ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Page 4 Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC SECTION I – PROJECT OVERVIEW General Description: The Redmond Integrated Service Center project site is located at the existing Sammamish River Business Park Buildings in Redmond, WA. The site address is 15511 NE 90th Street, Redmond, WA 98052. The proposed project site includes the redevelopment of approximately 1.65 acres. The proposed improvements will consist of the following major items of work: Demolition of both existing office buildings (combined footprint of 34,170 SF) Construction of two-story Hopelink building (approximate footprint of 14,000 SF) Construction of parking lot, utility, landscape, and lighting improvements. Proposed Site Stormwater Drainage: Based on the site location adjacent to the Sammamish River, the project proposes to directly discharge treated stormwater to the existing NE 90th Street public stormwater conveyance system directly north of the project site. The stormwater conveyance discharges via 18” outfall to the Sammamish River. To decrease the volume and peak flows of stormwater runoff from the project site into the public conveyance system, onsite infiltration galleries are proposed to infiltrate clean runoff from the building’s roof totaling approximately 15,000 square feet (0.35 acres). Based on the project site’s location within Wellhead Protection Zone 2, by code only clean stormwater runoff is allowed to be considered for infiltration. This basin analysis addresses the existing NE 90th Street conveyance system hydraulic capacity. See Figure 1 for the Vicinity Map. ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Page 5 Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC FIGURE 1 – VICINITY MAP SECTION II – EXISTING CONDITIONS The basin draining to the existing NE 90th Street conveyance and outfall is approximately 14.0 acres of developed commercial lots (Manufacturing Park zoning) and City of Redmond right-of-way. The existing storm drainage system is located primarily within NE 90th Street flowing approximately 1000’ east to an outfall to the Sammamish River. The conveyance system is comprised of 12” and 18” pipes within the NE 90th Street right-of-way, and an additional contributing branch flowing north on154th Ave NE. The conveyance system receives contributing off-site flows from 3 properties including the proposed project site. See Figure 2 for the Basin Map. The Drainage Report prepared by Entranco, Inc. for construction of the NE 90th Street conveyance and outfall, dated May 1999, noted a history of flooding at the project intersection and options were being evaluated with the City of Redmond to alleviate flooding at the intersection. Approximate Basin Area ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Page 6 Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC SECTION III – ANALYSIS River Tail Water: The analysis evaluates the hydraulic capacity of the NE 90th Street conveyance system during a specific flood event in receiving water body, the Sammamish River. The 10, 50, and 100 year flood stages of the river at the outfall were interpolated from the current Sammamish River FEMA Flood Profiles. See Appendix A. For the purposes of this basin analysis, a backwater analysis was performed assuming a tailwater condition at the river outfall equal to the 10-year flood stage of the Sammamish River. Sammamish River FEMA Flood Profile Sub-Basin Areas: The proposed project site and two additional off-site properties were modeled as 80% impervious/20% pervious, the maximum impervious coverage allowed by code for the Manufacturing Park zone. No infiltration of onsite stormwater from the project site was taken in consideration for this basin analysis, but any onsite infiltration proposed in the final site design will benefit the conveyance system and drainage for the whole entire basin. City of Redmond GIS information as well as as-built plans for the two off-site properties connected to NE 90th Street system indicate perforated pipes through the sites for infiltration of stormwater. Based on the use of perforated infiltration pipes, the analysis assumes that 50% of runoff from these two properties will remain on the respective properties and not flow to the NE 90th Street conveyance system. See Appendix B for the Sub-Basin area analysis and WWHM 50-year flows. Return Period River Stage (NAVD 88) 10 year 30.2 ft 50 year 32.7 ft 100 year 33.6 ft ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Page 7 Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC FIGURE 2 – BASIN MAP ATTACHMENT Q ---PAGE BREAK--- coterra 321 3rd Avenue South, Suite 307 Seattle, Washington 98104 [PHONE REDACTED] coterraengineering.com ENGINEERING PLLC ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Page 8 Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC Backwater Analysis: Hydraulic capacity was analyzed using a 50-year peak backwater analysis of the NE 90th Street system assuming a 10-year flood stage of the Sammamish River at the outfall. Sub-basin 50-year flows tributary to each catch basin from right-of-way areas and off-site properties was determined using the Western Washington Hydrology Model (WWHM2012). In the proposed condition, the backwater analysis indicates the hydraulic grade line of the conveyance system above the rim elevations of several drainage structures to the west and south of the NE 90th Street / 154th Avenue NE intersection. The Washington State Department of Ecology 2005 and City of Redmond 2012 Stormwater Management Technical Notebook note in the direct discharge exemption for a project site, “the conveyance system between the project site and the exempt receiving water shall have sufficient hydraulic capacity to convey discharges from future build-out conditions of the site, and the existing conditions from non-project areas from which runoff is or will be collected.” The backwater analysis indicates sufficient hydraulic capacity, via the hydraulic grade line, from the project site to the outfall at the Sammamish River. See Appendix C for the proposed condition backwater analysis. SECTION IV – UNIFORM FLOW ANALYSIS A uniform flow analysis was performed on the existing NE 90th Street conveyance system assuming the full build-out (80% impervious/20% pervious) of the proposed site and without considering any onsite infiltration. The system was analyzed using a 50-year, 24-hour storm with sub-basin flows calculated using WWHM2012. See Appendix D for the Uniform Flow Analysis. Based strictly on the uniform flow analysis, without considering the river tail water elevation and backwater effects, the conveyance system has sufficient capacity to convey stormwater discharges from the full built-out project site and the non- project areas which contribute to the NE 90th Street conveyance system. The 50-year, 24- hour flows do not exceed the uniform flow analysis capacity of the conveyance system. Due to a surveying error, it was originally determined that the conveyance pipe (at incorrectly recorded existing slope) could not convey the 50-year flows. However, the river elevation at the outfall and its backwater effects must be considered in the overall analysis of the existing conveyance system and contributing flows to the system. ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Page 9 Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC SECTION V – COMPARISON TO EXISTING CONDITIONS In addition to the proposed project conditions, a 50-year backwater analysis and uniform flow analysis were also completed based on the existing site conditions. An area analysis of the site survey indicates the site impervious coverage currently exceeds the maximum 80% allowed by Code in the MP zone. With the rest of the basin area coverage remaining the same as the earlier analyses in this report, the existing basin in a 50-year storm event and 10-year flood stage on the Sammamish River can expect to be flooded by up to 0.5’ of additional stormwater. The proposed project will decrease the depth of overtopping of drainage structures on the existing NE 90th Street conveyance system. See Appendix E for existing basin backwater and uniform flow analyses. SECTION VI – COMPARISON TO FULL ONSITE DETENTION Furthermore, a 50-year backwater analysis and uniform flow analysis were also completed to analyze the effects of a full onsite stormwater detention system would release stormwater from the project site to the existing conveyance system meeting the 2005 duration standard to match a historically forested site condition. The 50-year peak release rate from the project site under this scenario is just 0.09 cfs. Yet, the 50-year backwater analysis with full detention still indicates overtopping of drainage structures upstream in the conveyance system. See Appendix F for the full onsite detention scenario backwater and uniform flow analyses. SECTION VII – PROPOSED IMPROVEMENTS Based on the modeled results of the full onsite detention scenario, which still indicates a backwater condition in the conveyance system and overtopping of structures upstream of the project site, infiltration of clean runoff from the 0.35 acres of roof area on the project are proposed to decrease overall stormwater discharge to the existing conveyance system. A capture area of 15,000 square feet, approximately 20% of the entire project site, will be routed to onsite infiltration galleries. Based on the project’s location in the Wellhead Protection Zone 2, this is the maximum extent of infiltration allowed by code on the project property. The infiltration galleries are sited to be above the yearly average maximum groundwater height, such that roof runoff will infiltrate through imported well-draining material down to existing outwash soils which are strong receptors of infiltration. ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Page 10 Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC This roof infiltration system will retain significant quantities of site runoff within the project site’s area and decrease the quantity and peak flows of stormwater off of the project site and into the existing NE 90th Street conveyance system. The proposed onsite stormwater system will not only maintain the existing operating condition of the conveyance system, but provide improvement over existing conditions and full detention scenarios by decreasing contributing runoff from the project to the NE 90th Street conveyance system. SECTION VIII – CONCLUSION The basin analysis confirms the City’s reports that portions of the existing NE 90th Street conveyance system is overtopped by stormwater runoff during significant storm events which coincide with elevated river levels at the system’s outfall in the Sammamish River. The uniform flow analysis shows the existing pipes have the capacity to move the existing and proposed flows of stormwater through the system, but the entire system is inundated by the river elevation and backs up in the conveyance system and upstream catch basins. The basin analysis also confirms that this backwater condition is not improved or resolved by completely detaining all stormwater runoff onsite, as the entire conveyance system and likely the onsite detention system as well, is fully inundated by stormwater and backed-up river water during large storm events. This project proposes to mitigate on the project site a portion of the volume and peak rate of stormwater which it discharges to the existing NE 90th Street conveyance system by infiltrating to the extent feasible clean stormwater runoff from the roof directly into the ground on the project site. This will decrease the volume and peak rate of runoff discharged to the existing public conveyance system and the river outfall. This proposal will decrease the magnitude of flooding and overtopping conditions observed in the basin area compared to the existing site and basin conditions. ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC APPENDIX A – SAMMAMISH RIVER FEMA FLOOD PROFILES ATTACHMENT Q ---PAGE BREAK--- ATTACHMENT Q ---PAGE BREAK--- ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC APPENDIX B – SUB-BASIN FLOWS ATTACHMENT Q ---PAGE BREAK--- SUB BASIN FLOWS (WWHM) Project Name: HOPELINK RISC - NE 90th Street Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR CB # (Figure) CB # (City GIS ID) AREA TOTAL (SF) AREA TOTAL (AC) IMPERVIOUS (AC) PERVIOUS (AC) 50 YR FLOW (cfs) 1 21394 0 0.000 0.000 0.000 0.000 Solid Lid 2 21397 1814 0.042 0.021 0.021 0.020 Approx 50/50 Impervious/Pervious (KC Trail) 3 21370 200201 1.736 1.363 0.373 2.220 4 1634 0 0.000 0.000 0.000 0.000 Solid Lid 5 23077 1669 0.038 0.038 0.000 0.027 100% Impervious 6 21580 0 0.000 0.000 0.000 0.000 Solid Lid (Flow Splitter) 7 21237 3654 0.084 0.084 0.000 0.059 100% Impervious 8 21166 5182 0.119 0.119 0.000 0.084 100% Impervious 9 21161 1467 0.034 0.034 0.000 0.024 100% Impervious 10 21379 2040 0.047 0.047 0.000 0.033 100% Impervious 11 21381 1689 0.039 0.039 0.000 0.028 100% Impervious 12 21162 5363 0.123 0.123 0.000 0.087 100% Impervious 13 21383 5085 0.117 0.117 0.000 0.083 100% Impervious 14 21384 14782 0.339 0.339 0.000 0.263 100% Impervious 20 21549 0 0.000 0.000 0.000 0.000 Solid Lid 21 21802 13139 0.302 0.302 0.000 0.104 100% Impervious 22 21753 9657 0.222 0.222 0.000 0.157 100% Impervious 23 21751 5493 0.126 0.126 0.000 0.089 100% Impervious 24 21752 6420 0.147 0.147 0.000 0.104 100% Impervious 30 21378 3970 0.091 0.091 0.000 0.064 100% Impervious 31 21380 2448 0.056 0.056 0.000 0.040 100% Impervious 32 5852 329327 7.560 6.048 1.512 2.2964 80/20% Impervious max./Pervious by zoning Notes Approx 50/50 Impervious/Pervious offsite (trail) [ 0.086 ac 80/20 onsite [ 1.65 ac ] and 80/20 adjacent site [ 3.81 ac ] coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC APPENDIX C – PROPOSED CONDITION BACKWATER ANALYSIS ATTACHMENT Q ---PAGE BREAK--- BACKWATER ANALYSIS - PROPOSED PROJECT Project Name: HOPELINK RISC - NE 90th Street Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR Conveyance System Information Outlet Control Inlet Control Headwater Summation Overtopping Check Pipe Segment Surface Total Length Pipe Down- Down- Up- Up- Pipe Barrel Barrel Critical Critical TW TW Barrel Friction Entrance Entrance Entrance Exit Outlet Inlet Inlet Control Approach Bend Bend Q1 Q3 V1 Junction Head HW (HW - Rim) Over- CB/MH # CB/MH # Flow Flow L Size value Stream Stream Stream Stream Slope Velocity Velocity Depth Depth Elev. Check Hyd. Loss HGL Ke Head Head Control Control Control HW Veloctiy Kb Head Head Loss Elev. Clearance topping Down Up Q Qtot D Invert Rim Invert Rim Head Ratio Rad. Elev. Loss Loss Elev. HW/D Elev. Elev. Head Loss Loss Total Check CFS CFS FT IN FT FT FT FT % FPS FT FT FT FT FT FT FT FT FT FT FT FT FT FT FT CFS CFS FPS FT FT FT FT RIVER OUTFALL CB #01 (21394) 0.000 5.78 65.0 18 0.012 23.31 24.81 23.59 31.29 0.43% 3.27 0.17 0.78 1.17 30.20 30.20 0.38 0.17 30.37 0.50 0.08 0.17 30.62 1.35 25.62 30.62 0.17 0.02 0.00 5.78 3.27 0.00 30.45 -0.84 Okay CB #01 (21394) CB #02 (21397) 0.020 5.78 76.0 18 0.012 23.64 31.29 24.22 34.23 0.76% 3.27 0.17 0.78 1.17 30.45 30.45 0.38 0.20 30.65 0.50 0.08 0.17 30.90 1.35 26.25 30.90 0.16 0.02 0.00 5.76 3.27 0.00 30.74 -3.49 Okay CB #02 (21397) CB #03 (21370) 2.220 5.76 155.6 18 0.012 24.22 34.23 24.72 32.77 0.32% 3.26 0.16 0.78 1.17 30.74 30.74 0.38 0.40 31.13 0.50 0.08 0.16 31.38 1.35 26.75 31.38 0.06 0.02 0.00 3.54 3.26 0.00 31.32 -1.45 Okay CB #03 (21370) CB #04 (1634) 0.000 3.54 120.5 18 0.012 24.72 32.77 25.29 34.59 0.47% 2.00 0.06 0.62 0.47 31.32 31.32 0.38 0.12 31.44 0.50 0.03 0.06 31.53 0.90 26.64 31.53 0.06 0.02 0.00 3.54 2.00 0.00 31.47 -3.12 Okay CB #04 (1634) CB #05 (23077) 0.027 3.54 19.6 18 0.012 25.29 34.59 25.48 33.80 0.97% 2.00 0.06 0.62 0.36 31.47 31.47 0.38 0.02 31.49 0.50 0.03 0.06 31.58 0.90 26.83 31.58 0.06 1.33 0.08 3.51 2.00 0.08 31.60 -2.20 Okay CB #05 (23077) CB #06 (21580) 0.000 3.51 25.9 18 0.012 25.50 33.80 25.68 33.33 0.69% 1.99 0.06 0.62 0.15 31.60 31.60 0.38 0.02 31.63 0.50 0.03 0.06 31.72 0.90 27.03 31.72 0.06 0.02 0.00 3.51 1.99 0.00 31.66 -1.67 Okay CB #06 (21580) CB #07 (21237) 0.059 3.51 34.5 18 0.012 25.68 33.33 26.02 32.82 0.99% 1.99 0.06 0.62 0.15 31.66 31.66 0.38 0.03 31.69 0.50 0.03 0.06 31.79 0.90 27.37 31.79 0.04 1.33 0.08 3.00 0.45 1.99 0.01 0.09 31.83 -0.99 Okay CB #07 (21237) CB #08 (21166) 0.084 3.00 51.0 18 0.012 26.02 32.82 26.48 32.98 0.90% 1.70 0.04 0.59 0.13 31.83 31.83 0.38 0.04 31.87 0.50 0.02 0.04 31.93 0.85 27.76 31.93 0.04 1.33 0.06 2.92 1.70 0.06 31.95 -1.03 Okay CB #08 (21166) CB #09 (21161) 0.024 2.92 70.0 18 0.012 26.48 32.98 27.09 32.84 0.87% 1.65 0.04 0.58 0.87 31.95 31.95 0.38 0.05 32.00 0.50 0.02 0.04 32.06 0.85 28.37 32.06 0.04 0.02 0.00 2.89 1.65 0.00 32.02 -0.82 Okay CB #09 (21161) CB #10 (21379) 0.033 2.89 65.0 18 0.012 27.19 32.84 27.95 33.25 1.17% 1.64 0.04 0.58 0.87 32.02 32.02 0.38 0.04 32.06 0.50 0.02 0.04 32.12 0.85 29.23 32.12 0.01 0.02 0.00 0.46 2.40 1.64 0.05 0.05 32.17 -1.08 Okay CB #10 (21379) CB #11 (21381) 0.028 0.46 78.0 12 0.012 27.95 33.25 28.60 31.58 0.83% 0.59 0.01 0.21 0.21 32.17 32.17 0.25 0.01 32.18 0.50 0.00 0.01 32.19 0.10 28.70 32.19 0.00 0.02 0.00 0.43 0.59 0.00 32.18 0.60 Overtopping!! CB #11 (21381) CB #12 (21162) 0.087 0.43 190.0 12 0.012 28.60 31.58 30.15 31.94 0.82% 0.55 0.00 0.16 0.16 32.18 32.18 0.25 0.02 32.20 0.50 0.00 0.00 32.21 0.10 30.25 32.21 0.00 0.02 0.00 0.35 0.55 0.00 32.21 0.27 Overtopping!! CB #12 (21162) CB #13 (21383) 0.083 0.35 63.0 12 0.012 30.15 31.94 30.28 32.65 0.21% 0.44 0.00 0.15 0.15 32.21 32.21 0.25 0.01 32.21 0.50 0.00 0.00 32.22 0.10 30.38 32.22 0.00 1.33 0.00 0.26 0.44 0.00 32.22 -0.43 Okay CB #13 (21383) CB #14 (21384) 0.263 0.26 41.0 12 0.012 30.28 32.65 30.38 32.63 0.24% 0.33 0.00 0.10 0.10 32.22 32.22 0.25 0.00 32.22 0.50 0.00 0.00 32.22 0.10 30.48 32.22 0.01 0.02 0.00 0.45 0.33 0.00 32.22 -0.41 Okay CB #7 CB #20 (21549) 0.000 0.45 33.6 12 0.012 26.17 32.82 27.59 33.09 4.23% 0.58 0.01 0.31 0.31 32.22 32.22 0.25 0.00 32.22 0.50 0.00 0.01 32.23 0.50 28.09 32.23 0.01 0.48 0.00 0.45 0.58 0.00 32.23 -0.86 Okay CB #20 (21549) CB #21 (21802) 0.104 0.45 39.0 12 0.012 27.79 33.09 29.79 32.49 5.13% 0.58 0.01 0.31 0.31 32.23 32.23 0.25 0.01 32.23 0.50 0.00 0.01 32.24 0.50 30.29 32.24 0.00 0.48 0.00 0.25 0.10 0.58 0.00 0.00 32.24 -0.25 Caution CB #21 (21802) CB #22 (21753) 0.157 0.25 204.0 12 0.012 29.79 32.49 31.97 34.72 1.07% 0.31 0.00 0.21 0.21 32.24 32.24 0.25 0.01 32.97 0.50 0.00 0.00 32.97 0.10 32.07 32.97 0.00 1.33 0.00 0.09 0.31 0.00 32.97 -1.75 Okay CB #22 (21753) CB #23 (21751) 0.089 0.09 47.0 12 0.012 32.12 34.72 32.81 34.96 1.47% 0.11 0.00 0.12 0.12 32.97 32.97 0.25 0.00 33.81 0.50 0.00 0.00 33.81 0.10 32.91 33.81 0.00 0.02 0.00 0.10 0.11 0.00 33.81 -1.15 Okay CB #21 (21802) CB #24 (21752) 0.104 0.10 47.0 12 0.013 30.39 32.49 31.12 32.75 1.55% 0.13 0.00 0.13 0.13 33.81 33.81 0.25 0.00 33.81 0.50 0.00 0.00 33.81 0.10 31.22 33.81 0.03 0.05 0.00 2.40 0.13 0.00 33.78 1.03 Overtopping!! CB #10 (21379) CB #30 (21378) 0.064 2.40 42.0 18 0.013 28.38 33.25 28.51 33.46 0.31% 1.36 0.03 0.56 0.84 33.78 33.78 0.38 0.02 33.80 0.50 0.01 0.03 33.85 0.82 29.74 33.85 0.03 1.33 0.04 2.34 1.36 0.04 33.86 0.40 Overtopping!! CB #30 (21378) CB #31 (21380) 0.040 2.34 78.0 18 0.013 28.56 33.46 28.60 33.81 0.05% 1.32 0.03 0.56 0.84 33.86 33.86 0.38 0.04 33.90 0.50 0.01 0.03 33.94 0.82 29.83 33.94 0.13 0.48 0.01 2.30 1.32 0.01 33.82 0.01 Overtopping!! CB #31 (21380) CB #32 (5852) 2.296 2.30 80.0 12 0.012 29.40 33.81 30.27 34.00 1.09% 2.92 0.13 0.89 0.89 33.82 33.82 0.25 0.28 34.10 0.50 0.07 0.13 34.30 2.15 32.42 34.30 0.48 0.06 0.00 2.92 0.06 34.36 0.36 Overtopping!! 34.36 coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design 15011 Backwater Analysis.xls 9/1/2016 ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC APPENDIX D – PROPOSED SITE UNIFORM FLOW ANALYSIS ATTACHMENT Q ---PAGE BREAK--- UNIFORM FLOW ANALYSIS Project Name: NE 90th Street Outfall Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR CB CB Pipe Q50-yr Manning's Pipe Slope Qf Vf Uniform Uniform Upstream Size % Pipe Full Pipe Full Flow Velocity Check in cfs unitless cfs ft/s Check * Check RIVER OUTFALL CB #01 (21394) 18 5.78 0.012 0.43% 7.49 4.24 Ok Ok CB #01 (21394) CB #02 (21397) 18 5.78 0.012 0.76% 9.97 5.64 Ok Ok CB #02 (21397) CB #03 (21370) 18 5.76 0.012 0.32% 6.47 3.66 Warning! Ok CB #03 (21370) CB #04 (1634) 18 3.54 0.012 0.47% 7.85 4.44 Ok Ok CB #04 (1634) CB #05 (23077) 18 3.54 0.012 0.97% 11.23 6.36 Ok Ok CB #05 (23077) CB #06 (21580) 18 3.51 0.012 0.69% 9.51 5.38 Ok Ok CB #06 (21580) CB #07 (21237) 18 3.51 0.012 0.99% 11.33 6.41 Ok Ok CB #07 (21237) CB #08 (21166) 18 3.00 0.012 0.90% 10.84 6.13 Ok Ok CB #08 (21166) CB #09 (21161) 18 2.92 0.012 0.87% 10.65 6.03 Ok Ok CB #09 (21161) CB #10 (21379) 18 2.89 0.012 1.17% 12.34 6.98 Ok Ok CB #10 (21379) CB #11 (21381) 12 0.46 0.012 0.83% 3.53 4.50 Ok Ok CB #11 (21381) CB #12 (21162) 12 0.43 0.012 0.82% 3.50 4.45 Ok Ok CB #12 (21162) CB #13 (21383) 12 0.35 0.012 0.21% 1.76 2.24 Ok Ok CB #13 (21383) CB #14 (21384) 12 0.26 0.012 0.24% 1.91 2.43 Ok Ok CB #7 CB #20 (21549) 12 0.45 0.012 4.23% 7.96 10.13 Ok Ok CB #20 (21549) CB #21 (21802) 12 0.45 0.012 5.13% 8.76 11.16 Ok Ok CB #21 (21802) CB #22 (21753) 12 0.25 0.012 1.07% 4.00 5.09 Ok Ok CB #22 (21753) CB #23 (21751) 12 0.09 0.012 1.47% 4.69 5.97 Ok Ok CB #21 (21802) CB #24 (21752) 12 0.10 0.013 1.55% 4.45 5.67 Ok Ok CB #10 (21379) CB #30 (21378) 18 2.40 0.013 0.31% 5.86 3.32 Ok Ok CB #30 (21378) CB #31 (21380) 18 2.34 0.013 0.05% 2.39 1.35 Warning! Ok CB #31 (21380) CB #32 (5852) 12 2.30 0.012 1.09% 4.04 5.14 Ok Ok coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC APPENDIX E – EXISTING CONDITION BACKWATER AND FLOW ANALYSES ATTACHMENT Q ---PAGE BREAK--- EXISTING SUB BASIN FLOWS (WWHM) Project Name: HOPELINK RISC - NE 90th Street Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR CB # (Figure) CB # (City GIS ID) AREA TOTAL (SF) AREA TOTAL (AC) IMPERVIOUS (AC) PERVIOUS (AC) 50 YR FLOW (cfs) 1 21394 0 0.000 0.000 0.000 0.000 Solid Lid 2 21397 1814 0.042 0.021 0.021 0.020 Approx 50/50 Impervious/Pervious 3 21370 200201 1.736 1.363 0.373 2.470 4 1634 0 0.000 0.000 0.000 0.000 Solid Lid 5 23077 1669 0.038 0.038 0.000 0.027 100% Impervious 6 21580 0 0.000 0.000 0.000 0.000 Solid Lid (Flow Splitter) 7 21237 3654 0.084 0.084 0.000 0.059 100% Impervious 8 21166 5182 0.119 0.119 0.000 0.084 100% Impervious 9 21161 1467 0.034 0.034 0.000 0.024 100% Impervious 10 21379 2040 0.047 0.047 0.000 0.033 100% Impervious 11 21381 1689 0.039 0.039 0.000 0.028 100% Impervious 12 21162 5363 0.123 0.123 0.000 0.087 100% Impervious 13 21383 5085 0.117 0.117 0.000 0.083 100% Impervious 14 21384 14782 0.339 0.339 0.000 0.263 100% Impervious 20 21549 0 0.000 0.000 0.000 0.000 Solid Lid 21 21802 13139 0.302 0.302 0.000 0.104 100% Impervious 22 21753 9657 0.222 0.222 0.000 0.157 100% Impervious 23 21751 5493 0.126 0.126 0.000 0.089 100% Impervious 24 21752 6420 0.147 0.147 0.000 0.104 100% Impervious 30 21378 3970 0.091 0.091 0.000 0.064 100% Impervious 31 21380 2448 0.056 0.056 0.000 0.040 100% Impervious 32 5852 329327 7.560 6.048 1.512 2.296 80/20% Impervious max./Pervious by zoning Notes Approx 50/50 Impervious/Pervious offsite (trail) [ 0.086 ac ] and 80/20 onsite [ 1.65 ac ] and 80/20 adjacent site [ 3.81 ac ] coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design ATTACHMENT Q ---PAGE BREAK--- BACKWATER ANALYSIS - EXISTING BASIN Project Name: HOPELINK RISC - NE 90th Street Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR Conveyance System Information Outlet Control Inlet Control Headwater Summation Overtopping Check Pipe Segment Surface Total Length Pipe Down- Down- Up- Up- Pipe Barrel Barrel Critical Critical TW TW Barrel Friction Entrance Entrance Entrance Exit Outlet Inlet Inlet Control Approach Bend Bend Q1 Q3 V1 Junction Head HW (HW - Rim) Over- CB/MH # CB/MH # Flow Flow L Size value Stream Stream Stream Stream Slope Velocity Velocity Depth Depth Elev. Check Hyd. Loss HGL Ke Head Head Control Control Control HW Veloctiy Kb Head Head Loss Elev. Clearance topping Down Up Q Qtot D Invert Rim Invert Rim Head Ratio Rad. Elev. Loss Loss Elev. HW/D Elev. Elev. Head Loss Loss Total Check CFS CFS FT IN FT FT FT FT % FPS FT FT FT FT FT FT FT FT FT FT FT FT FT FT FT CFS CFS FPS FT FT FT FT RIVER OUTFALL CB #01 (21394) 0.000 6.03 65.0 18 0.012 23.31 24.81 23.59 31.29 0.43% 3.41 0.18 0.78 1.17 30.20 30.20 0.38 0.18 30.38 0.50 0.09 0.18 30.65 1.35 25.62 30.65 0.18 0.02 0.00 6.03 3.41 0.00 30.48 -0.81 Okay CB #01 (21394) CB #02 (21397) 0.020 6.03 76.0 18 0.012 23.64 31.29 24.22 34.23 0.76% 3.41 0.18 0.78 1.17 30.48 30.48 0.38 0.21 30.69 0.50 0.09 0.18 30.96 1.35 26.25 30.96 0.18 0.02 0.00 6.01 3.41 0.00 30.78 -3.45 Okay CB #02 (21397) CB #03 (21370) 2.470 6.01 155.6 18 0.012 24.22 34.23 24.72 32.77 0.32% 3.40 0.18 0.78 1.17 30.78 30.78 0.38 0.43 31.22 0.50 0.09 0.18 31.49 1.35 26.75 31.49 0.06 0.02 0.00 3.54 3.40 0.00 31.43 -1.34 Okay CB #03 (21370) CB #04 (1634) 0.000 3.54 120.5 18 0.012 24.72 32.77 25.29 34.59 0.47% 2.00 0.06 0.62 0.47 31.43 31.43 0.38 0.12 31.54 0.50 0.03 0.06 31.64 0.90 26.64 31.64 0.06 0.02 0.00 3.54 2.00 0.00 31.57 -3.02 Okay CB #04 (1634) CB #05 (23077) 0.027 3.54 19.6 18 0.012 25.29 34.59 25.48 33.80 0.97% 2.00 0.06 0.62 0.36 31.57 31.57 0.38 0.02 31.59 0.50 0.03 0.06 31.69 0.90 26.83 31.69 0.06 1.33 0.08 3.51 2.00 0.08 31.71 -2.09 Okay CB #05 (23077) CB #06 (21580) 0.000 3.51 25.9 18 0.012 25.50 33.80 25.68 33.33 0.69% 1.99 0.06 0.62 0.15 31.71 31.71 0.38 0.02 31.73 0.50 0.03 0.06 31.83 0.90 27.03 31.83 0.06 0.02 0.00 3.51 1.99 0.00 31.77 -1.56 Okay CB #06 (21580) CB #07 (21237) 0.059 3.51 34.5 18 0.012 25.68 33.33 26.02 32.82 0.99% 1.99 0.06 0.62 0.15 31.77 31.77 0.38 0.03 31.80 0.50 0.03 0.06 31.89 0.90 27.37 31.89 0.04 1.33 0.08 3.00 0.45 1.99 0.01 0.09 31.93 -0.89 Okay CB #07 (21237) CB #08 (21166) 0.084 3.00 51.0 18 0.012 26.02 32.82 26.48 32.98 0.90% 1.70 0.04 0.59 0.13 31.93 31.93 0.38 0.04 31.97 0.50 0.02 0.04 32.04 0.85 27.76 32.04 0.04 1.33 0.06 2.92 1.70 0.06 32.05 -0.93 Okay CB #08 (21166) CB #09 (21161) 0.024 2.92 70.0 18 0.012 26.48 32.98 27.09 32.84 0.87% 1.65 0.04 0.58 0.87 32.05 32.05 0.38 0.05 32.10 0.50 0.02 0.04 32.16 0.85 28.37 32.16 0.04 0.02 0.00 2.89 1.65 0.00 32.12 -0.72 Okay CB #09 (21161) CB #10 (21379) 0.033 2.89 65.0 18 0.012 27.19 32.84 27.95 33.25 1.17% 1.64 0.04 0.58 0.87 32.12 32.12 0.38 0.04 32.16 0.50 0.02 0.04 32.23 0.85 29.23 32.23 0.01 0.02 0.00 0.46 2.40 1.64 0.05 0.05 32.27 -0.98 Okay CB #10 (21379) CB #11 (21381) 0.028 0.46 78.0 12 0.012 27.95 33.25 28.60 31.58 0.83% 0.59 0.01 0.21 0.21 32.27 32.27 0.25 0.01 32.28 0.50 0.00 0.01 32.29 0.10 28.70 32.29 0.00 0.02 0.00 0.43 0.59 0.00 32.29 0.71 Overtopping!! CB #11 (21381) CB #12 (21162) 0.087 0.43 190.0 12 0.012 28.60 31.58 30.15 31.94 0.82% 0.55 0.00 0.16 0.16 32.29 32.29 0.25 0.02 32.31 0.50 0.00 0.00 32.32 0.10 30.25 32.32 0.00 0.02 0.00 0.35 0.55 0.00 32.31 0.37 Overtopping!! CB #12 (21162) CB #13 (21383) 0.083 0.35 63.0 12 0.012 30.15 31.94 30.28 32.65 0.21% 0.44 0.00 0.15 0.15 32.31 32.31 0.25 0.01 32.32 0.50 0.00 0.00 32.32 0.10 30.38 32.32 0.00 1.33 0.00 0.26 0.44 0.00 32.32 -0.33 Okay CB #13 (21383) CB #14 (21384) 0.263 0.26 41.0 12 0.012 30.28 32.65 30.38 32.63 0.24% 0.33 0.00 0.10 0.10 32.32 32.32 0.25 0.00 32.33 0.50 0.00 0.00 32.33 0.10 30.48 32.33 0.01 0.02 0.00 0.45 0.33 0.00 32.32 -0.31 Okay CB #7 CB #20 (21549) 0.000 0.45 33.6 12 0.012 26.17 32.82 27.59 33.09 4.23% 0.58 0.01 0.31 0.31 32.32 32.32 0.25 0.00 32.33 0.50 0.00 0.01 32.34 0.50 28.09 32.34 0.01 0.48 0.00 0.45 0.58 0.00 32.33 -0.76 Okay CB #20 (21549) CB #21 (21802) 0.104 0.45 39.0 12 0.012 27.79 33.09 29.79 32.49 5.13% 0.58 0.01 0.31 0.31 32.33 32.33 0.25 0.01 32.34 0.50 0.00 0.01 32.35 0.50 30.29 32.35 0.00 0.48 0.00 0.25 0.10 0.58 0.00 0.00 32.35 -0.14 Caution CB #21 (21802) CB #22 (21753) 0.157 0.25 204.0 12 0.012 29.79 32.49 31.97 34.72 1.07% 0.31 0.00 0.21 0.21 32.35 32.35 0.25 0.01 32.97 0.50 0.00 0.00 32.97 0.10 32.07 32.97 0.00 1.33 0.00 0.09 0.31 0.00 32.97 -1.75 Okay CB #22 (21753) CB #23 (21751) 0.089 0.09 47.0 12 0.012 32.12 34.72 32.81 34.96 1.47% 0.11 0.00 0.12 0.12 32.97 32.97 0.25 0.00 33.81 0.50 0.00 0.00 33.81 0.10 32.91 33.81 0.00 0.02 0.00 0.10 0.11 0.00 33.81 -1.15 Okay CB #21 (21802) CB #24 (21752) 0.104 0.10 47.0 12 0.013 30.39 32.49 31.12 32.75 1.55% 0.13 0.00 0.13 0.13 33.81 33.81 0.25 0.00 33.81 0.50 0.00 0.00 33.81 0.10 31.22 33.81 0.03 0.05 0.00 2.40 0.13 0.00 33.78 1.03 Overtopping!! CB #10 (21379) CB #30 (21378) 0.064 2.40 42.0 18 0.013 28.38 33.25 28.51 33.46 0.31% 1.36 0.03 0.56 0.84 33.78 33.78 0.38 0.02 33.80 0.50 0.01 0.03 33.85 0.82 29.74 33.85 0.03 1.33 0.04 2.34 1.36 0.04 33.86 0.40 Overtopping!! CB #30 (21378) CB #31 (21380) 0.040 2.34 78.0 18 0.013 28.56 33.46 28.60 33.81 0.05% 1.32 0.03 0.56 0.84 33.86 33.86 0.38 0.04 33.90 0.50 0.01 0.03 33.94 0.82 29.83 33.94 0.13 0.48 0.01 2.30 1.32 0.01 33.82 0.01 Overtopping!! CB #31 (21380) CB #32 (5852) 2.296 2.30 80.0 12 0.012 29.40 33.81 30.27 33.50 1.09% 2.92 0.13 0.89 0.89 33.82 33.82 0.25 0.28 34.10 0.50 0.07 0.13 34.30 2.15 32.42 34.30 0.48 0.06 0.00 2.92 0.06 34.36 0.86 Overtopping!! 34.36 coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design 15011 Backwater Analysis-EXISTING.xls 9/1/2016 ATTACHMENT Q ---PAGE BREAK--- EXISTING BASIN UNIFORM FLOW ANALYSIS Project Name: NE 90th Street Outfall Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR CB CB Pipe Q50-yr Manning's Pipe Slope Qf Vf Uniform Uniform am Upstream Size % Pipe Full Pipe Full Flow Velocity Check in cfs unitless cfs ft/s Check * Check RIVER OUTFALL CB #01 (21394) 18 6.03 0.012 0.43% 7.49 4.24 Warning! Ok CB #01 (21394) CB #02 (21397) 18 6.03 0.012 0.76% 9.97 5.64 Ok Ok CB #02 (21397) CB #03 (21370) 18 6.01 0.012 0.32% 6.47 3.66 Warning! Ok CB #03 (21370) CB #04 (1634) 18 3.54 0.012 0.47% 7.85 4.44 Ok Ok CB #04 (1634) CB #05 (23077) 18 3.54 0.012 0.97% 11.23 6.36 Ok Ok CB #05 (23077) CB #06 (21580) 18 3.51 0.012 0.69% 9.51 5.38 Ok Ok CB #06 (21580) CB #07 (21237) 18 3.51 0.012 0.99% 11.33 6.41 Ok Ok CB #07 (21237) CB #08 (21166) 18 3.00 0.012 0.90% 10.84 6.13 Ok Ok CB #08 (21166) CB #09 (21161) 18 2.92 0.012 0.87% 10.65 6.03 Ok Ok CB #09 (21161) CB #10 (21379) 18 2.89 0.012 1.17% 12.34 6.98 Ok Ok CB #10 (21379) CB #11 (21381) 12 0.46 0.012 0.83% 3.53 4.50 Ok Ok CB #11 (21381) CB #12 (21162) 12 0.43 0.012 0.82% 3.50 4.45 Ok Ok CB #12 (21162) CB #13 (21383) 12 0.35 0.012 0.21% 1.76 2.24 Ok Ok CB #13 (21383) CB #14 (21384) 12 0.26 0.012 0.24% 1.91 2.43 Ok Ok 0.00 CB #7 CB #20 (21549) 12 0.45 0.012 4.23% 7.96 10.13 Ok Ok CB #20 (21549) CB #21 (21802) 12 0.45 0.012 5.13% 8.76 11.16 Ok Ok CB #21 (21802) CB #22 (21753) 12 0.25 0.012 1.07% 4.00 5.09 Ok Ok CB #22 (21753) CB #23 (21751) 12 0.09 0.012 1.47% 4.69 5.97 Ok Ok 0.00 CB #21 (21802) CB #24 (21752) 12 0.10 0.013 1.55% 4.45 5.67 Ok Ok 0.00 CB #10 (21379) CB #30 (21378) 18 2.40 0.013 0.31% 5.86 3.32 Ok Ok CB #30 (21378) CB #31 (21380) 18 2.34 0.013 0.05% 2.39 1.35 Warning! Ok CB #31 (21380) CB #32 (5852) 12 2.30 0.012 1.09% 4.04 5.14 Ok Ok coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC APPENDIX F – FULL ONSITE DETENTION BACKWATER AND FLOW ANALYSES ATTACHMENT Q ---PAGE BREAK--- SUB BASIN FLOWS (WWHM) - WITH DETENTION Project Name: HOPELINK RISC - NE 90th Street Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR CB # (Figure) CB # (City GIS ID) AREA TOTAL (SF) AREA TOTAL (AC) IMPERVIOUS (AC) PERVIOUS (AC) 50 YR FLOW (cfs) 1 21394 0 0.000 0.000 0.000 0.000 Solid Lid 2 21397 1814 0.042 0.021 0.021 0.020 Approx 50/50 Impervious/Pervious 3 21370 3742 1.736 1.363 0.373 1.150 4 1634 0 0.000 0.000 0.000 0.000 Solid Lid 5 23077 1669 0.038 0.038 0.027 0.027 6 21580 0 0.000 0.000 0.000 0.000 Solid Lid (Flow Splitter) 7 21237 3654 0.084 0.084 0.000 0.059 100% Impervious 8 21166 5182 0.119 0.119 0.000 0.084 100% Impervious 9 21161 1467 0.034 0.034 0.000 0.024 100% Impervious 10 21379 2040 0.047 0.047 0.000 0.033 100% Impervious 11 21381 1689 0.039 0.039 0.000 0.028 100% Impervious 12 21162 5363 0.123 0.123 0.000 0.087 100% Impervious 13 21383 5085 0.117 0.117 0.000 0.083 100% Impervious 14 21384 14782 0.339 0.339 0.000 0.263 100% Impervious 20 21549 0 0.000 0.000 0.000 0.000 Solid Lid? 21 21802 13139 0.302 0.302 0.000 0.104 100% Impervious 22 21753 9657 0.222 0.222 0.000 0.157 100% Impervious 23 21751 5493 0.126 0.126 0.000 0.089 100% Impervious 24 21752 6420 0.147 0.147 0.000 0.104 100% Impervious 30 21378 3970 0.091 0.091 0.000 0.064 100% Impervious 31 21380 2448 0.056 0.056 0.000 0.040 100% Impervious 32 5852 329327 7.560 6.048 1.512 2.296 80/20% Impervious max./Pervious by zoning Notes Approx 50/50 Impervious/Pervious offsite (trail) [ 0.086 ac ] and 80/20 onsite [ 1.65 ac ] and 80/20 adjacent site [ 3.81 ac ] coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design ATTACHMENT Q ---PAGE BREAK--- BACKWATER ANALYSIS - WITH DETENTION Project Name: HOPELINK RISC - NE 90th Street Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR Conveyance System Information Outlet Control Inlet Control Headwater Summation Overtopping Check Pipe Segment Surface Total Length Pipe Down- Down- Up- Up- Pipe Barrel Barrel Critical Critical TW TW Barrel Friction Entrance Entrance Entrance Exit Outlet Inlet Inlet Control Approach Bend Bend Q1 Q3 V1 Junction Head HW (HW - Rim) Over- CB/MH # CB/MH # Flow Flow L Size value Stream Stream Stream Stream Slope Velocity Velocity Depth Depth Elev. Check Hyd. Loss HGL Ke Head Head Control Control Control HW Veloctiy Kb Head Head Loss Elev. Clearance topping Down Up Q Qtot D Invert Rim Invert Rim Head Ratio Rad. Elev. Loss Loss Elev. HW/D Elev. Elev. Head Loss Loss Total Check CFS CFS FT IN FT FT FT FT % FPS FT FT FT FT FT FT FT FT FT FT FT FT FT FT FT CFS CFS FPS FT FT FT FT RIVER OUTFALL CB #01 (21394) 0.000 4.71 65.0 18 0.012 23.31 24.81 23.59 31.29 0.43% 2.67 0.11 0.78 1.17 30.20 30.20 0.38 0.11 30.31 0.50 0.06 0.11 30.48 1.35 25.62 30.48 0.11 0.02 0.00 4.71 2.67 0.00 30.37 -0.92 Okay CB #01 (21394) CB #02 (21397) 0.020 4.71 76.0 18 0.012 23.64 31.29 24.22 34.23 0.76% 2.67 0.11 0.78 1.17 30.37 30.37 0.38 0.13 30.50 0.50 0.06 0.11 30.66 1.35 26.25 30.66 0.11 0.02 0.00 4.69 2.67 0.00 30.56 -3.67 Okay CB #02 (21397) CB #03 (21370) 1.150 4.69 155.6 18 0.012 24.22 34.23 24.72 32.77 0.32% 2.65 0.11 0.78 1.17 30.56 30.56 0.38 0.26 30.82 0.50 0.05 0.11 30.98 1.35 26.75 30.98 0.06 0.02 0.00 3.54 2.65 0.00 30.92 -1.85 Okay CB #03 (21370) CB #04 (1634) 0.000 3.54 120.5 18 0.012 24.72 32.77 25.29 34.59 0.47% 2.00 0.06 0.62 0.47 30.92 30.92 0.38 0.12 31.04 0.50 0.03 0.06 31.13 0.90 26.64 31.13 0.06 0.02 0.00 3.54 2.00 0.00 31.07 -3.52 Okay CB #04 (1634) CB #05 (23077) 0.027 3.54 19.6 18 0.012 25.29 34.59 25.48 33.80 0.97% 2.00 0.06 0.62 0.36 31.07 31.07 0.38 0.02 31.09 0.50 0.03 0.06 31.18 0.90 26.83 31.18 0.06 1.33 0.08 3.51 2.00 0.08 31.21 -2.59 Okay CB #05 (23077) CB #06 (21580) 0.000 3.51 25.9 18 0.012 25.50 33.80 25.68 33.33 0.69% 1.99 0.06 0.62 0.15 31.21 31.21 0.38 0.02 31.23 0.50 0.03 0.06 31.32 0.90 27.03 31.32 0.06 0.02 0.00 3.51 1.99 0.00 31.26 -2.07 Okay CB #06 (21580) CB #07 (21237) 0.059 3.51 34.5 18 0.012 25.68 33.33 26.02 32.82 0.99% 1.99 0.06 0.62 0.15 31.26 31.26 0.38 0.03 31.29 0.50 0.03 0.06 31.39 0.90 27.37 31.39 0.04 1.33 0.08 3.00 0.45 1.99 0.01 0.09 31.43 -1.39 Okay CB #07 (21237) CB #08 (21166) 0.084 3.00 51.0 18 0.012 26.02 32.82 26.48 32.98 0.90% 1.70 0.04 0.59 0.13 31.43 31.43 0.38 0.04 31.47 0.50 0.02 0.04 31.53 0.85 27.76 31.53 0.04 1.33 0.06 2.92 1.70 0.06 31.55 -1.43 Okay CB #08 (21166) CB #09 (21161) 0.024 2.92 70.0 18 0.012 26.48 32.98 27.09 32.84 0.87% 1.65 0.04 0.58 0.87 31.55 31.55 0.38 0.05 31.60 0.50 0.02 0.04 31.66 0.85 28.37 31.66 0.04 0.02 0.00 2.89 1.65 0.00 31.62 -1.22 Okay CB #09 (21161) CB #10 (21379) 0.033 2.89 65.0 18 0.012 27.19 32.84 27.95 33.25 1.17% 1.64 0.04 0.58 0.87 31.62 31.62 0.38 0.04 31.66 0.50 0.02 0.04 31.72 0.85 29.23 31.72 0.01 0.02 0.00 0.46 2.40 1.64 0.05 0.05 31.77 -1.48 Okay CB #10 (21379) CB #11 (21381) 0.028 0.46 78.0 12 0.012 27.95 33.25 28.60 31.58 0.83% 0.59 0.01 0.21 0.21 31.77 31.77 0.25 0.01 31.78 0.50 0.00 0.01 31.79 0.10 28.70 31.79 0.00 0.02 0.00 0.43 0.59 0.00 31.78 0.20 Overtopping!! CB #11 (21381) CB #12 (21162) 0.087 0.43 190.0 12 0.012 28.60 31.58 30.15 31.94 0.82% 0.55 0.00 0.16 0.16 31.78 31.78 0.25 0.02 31.81 0.50 0.00 0.00 31.81 0.10 30.25 31.81 0.00 0.02 0.00 0.35 0.55 0.00 31.81 -0.13 Caution CB #12 (21162) CB #13 (21383) 0.083 0.35 63.0 12 0.012 30.15 31.94 30.28 32.65 0.21% 0.44 0.00 0.15 0.15 31.81 31.81 0.25 0.01 31.81 0.50 0.00 0.00 31.82 0.10 30.38 31.82 0.00 1.33 0.00 0.26 0.44 0.00 31.82 -0.83 Okay CB #13 (21383) CB #14 (21384) 0.263 0.26 41.0 12 0.012 30.28 32.65 30.38 32.63 0.24% 0.33 0.00 0.10 0.10 31.82 31.82 0.25 0.00 31.82 0.50 0.00 0.00 31.83 0.10 30.48 31.83 0.01 0.02 0.00 0.45 0.33 0.00 31.82 -0.81 Okay CB #7 CB #20 (21549) 0.000 0.45 33.6 12 0.012 26.17 32.82 27.59 33.09 4.23% 0.58 0.01 0.31 0.31 31.82 31.82 0.25 0.00 31.83 0.50 0.00 0.01 31.83 0.50 28.09 31.83 0.01 0.48 0.00 0.45 0.58 0.00 31.83 -1.26 Okay CB #20 (21549) CB #21 (21802) 0.104 0.45 39.0 12 0.012 27.79 33.09 29.79 32.49 5.13% 0.58 0.01 0.31 0.31 31.83 31.83 0.25 0.01 31.84 0.50 0.00 0.01 31.84 0.50 30.29 31.84 0.00 0.48 0.00 0.25 0.10 0.58 0.00 0.00 31.85 -0.64 Okay CB #21 (21802) CB #22 (21753) 0.157 0.25 204.0 12 0.012 29.79 32.49 31.97 34.72 1.07% 0.31 0.00 0.21 0.21 31.85 31.85 0.25 0.01 32.97 0.50 0.00 0.00 32.97 0.10 32.07 32.97 0.00 1.33 0.00 0.09 0.31 0.00 32.97 -1.75 Okay CB #22 (21753) CB #23 (21751) 0.089 0.09 47.0 12 0.012 32.12 34.72 32.81 34.96 1.47% 0.11 0.00 0.12 0.12 32.97 32.97 0.25 0.00 33.81 0.50 0.00 0.00 33.81 0.10 32.91 33.81 0.00 0.02 0.00 0.10 0.11 0.00 33.81 -1.15 Okay CB #21 (21802) CB #24 (21752) 0.104 0.10 47.0 12 0.013 30.39 32.49 31.12 32.75 1.55% 0.13 0.00 0.13 0.13 33.81 33.81 0.25 0.00 33.81 0.50 0.00 0.00 33.81 0.10 31.22 33.81 0.03 0.05 0.00 2.40 0.13 0.00 33.78 1.03 Overtopping!! CB #10 (21379) CB #30 (21378) 0.064 2.40 42.0 18 0.013 28.38 33.25 28.51 33.46 0.31% 1.36 0.03 0.56 0.84 33.78 33.78 0.38 0.02 33.80 0.50 0.01 0.03 33.85 0.82 29.74 33.85 0.03 1.33 0.04 2.34 1.36 0.04 33.86 0.40 Overtopping!! CB #30 (21378) CB #31 (21380) 0.040 2.34 78.0 18 0.013 28.56 33.46 28.60 33.81 0.05% 1.32 0.03 0.56 0.84 33.86 33.86 0.38 0.04 33.90 0.50 0.01 0.03 33.94 0.82 29.83 33.94 0.13 0.48 0.01 2.30 1.32 0.01 33.82 0.01 Overtopping!! CB #31 (21380) CB #32 (5852) 2.296 2.30 80.0 12 0.012 29.40 33.81 30.27 34.00 1.09% 2.92 0.13 0.89 0.89 33.82 33.82 0.25 0.28 34.10 0.50 0.07 0.13 34.30 2.15 32.42 34.30 0.48 0.06 0.00 2.92 0.06 34.36 0.36 Overtopping!! 34.36 coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design 15011 Backwater Analysis-DETENTION.xls 9/1/2016 ATTACHMENT Q ---PAGE BREAK--- UNIFORM FLOW ANALYSIS-WITH DETENTION Project Name: NE 90th Street Outfall Designed By: Max Berde Checked By: Peter Apostol Job Number: 15011 Storm Event: 50-YEAR CB CB Pipe Q50-yr Manning's Pipe Slope Qf Vf Uniform Uniform am Upstream Size % Pipe Full Pipe Full Flow Velocity Check in cfs unitless cfs ft/s Check * Check RIVER OUTFALL CB #01 (21394) 18 4.71 0.012 0.43% 7.49 4.24 Ok Ok CB #01 (21394) CB #02 (21397) 18 4.71 0.012 0.76% 9.97 5.64 Ok Ok CB #02 (21397) CB #03 (21370) 18 4.69 0.012 0.32% 6.47 3.66 Ok Ok CB #03 (21370) CB #04 (1634) 18 3.54 0.012 0.47% 7.85 4.44 Ok Ok CB #04 (1634) CB #05 (23077) 18 3.54 0.012 0.97% 11.23 6.36 Ok Ok CB #05 (23077) CB #06 (21580) 18 3.51 0.012 0.69% 9.51 5.38 Ok Ok CB #06 (21580) CB #07 (21237) 18 3.51 0.012 0.99% 11.33 6.41 Ok Ok CB #07 (21237) CB #08 (21166) 18 3.00 0.012 0.90% 10.84 6.13 Ok Ok CB #08 (21166) CB #09 (21161) 18 2.92 0.012 0.87% 10.65 6.03 Ok Ok CB #09 (21161) CB #10 (21379) 18 2.89 0.012 1.17% 12.34 6.98 Ok Ok CB #10 (21379) CB #11 (21381) 12 0.46 0.012 0.83% 3.53 4.50 Ok Ok CB #11 (21381) CB #12 (21162) 12 0.43 0.012 0.82% 3.50 4.45 Ok Ok CB #12 (21162) CB #13 (21383) 12 0.35 0.012 0.21% 1.76 2.24 Ok Ok CB #13 (21383) CB #14 (21384) 12 0.26 0.012 0.24% 1.91 2.43 Ok Ok 0.00 CB #7 CB #20 (21549) 12 0.45 0.012 4.23% 7.96 10.13 Ok Ok CB #20 (21549) CB #21 (21802) 12 0.45 0.012 5.13% 8.76 11.16 Ok Ok CB #21 (21802) CB #22 (21753) 12 0.25 0.012 1.07% 4.00 5.09 Ok Ok CB #22 (21753) CB #23 (21751) 12 0.09 0.012 1.47% 4.69 5.97 Ok Ok 0.00 CB #21 (21802) CB #24 (21752) 12 0.10 0.013 1.55% 4.45 5.67 Ok Ok 0.00 CB #10 (21379) CB #30 (21378) 18 2.40 0.013 0.31% 5.86 3.32 Ok Ok CB #30 (21378) CB #31 (21380) 18 2.34 0.013 0.05% 2.39 1.35 Warning! Ok CB #31 (21380) CB #32 (5852) 12 2.30 0.012 1.09% 4.04 5.14 Ok Ok coterra ENGINEERING PLLC collaborative civil engineering + site development + infrastructure design ATTACHMENT Q ---PAGE BREAK--- Redmond Integrated Service Center Proj. # 15011 NE 90th Street Basin Analysis Coterra Engineering PLLC APPENDIX G – AS-BUILT PLANS ATTACHMENT Q ---PAGE BREAK--- ATTACHMENT Q ---PAGE BREAK--- ATTACHMENT Q ---PAGE BREAK--- ATTACHMENT Q ---PAGE BREAK--- ATTACHMENT Q