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SWP272274(4)
HDA File No. 9566.00 DRAINAGE CALCULATIONS FOR ACT III THEATRES CITY OF RENTON, WASHINGTON APPROVED b • Prepared By: Bryant O. Mercil, P.E. HORTON DENNIS & ASSOCIATES, INC. 320 Second Avenue South S�� O. Kirkland, Washington 98033-6687 �4�oF w car Phone: (206) 822-2525 'QP� o Fax: (206) 822-8758 "' z b a 27991 w May 15, 1995 �GISmE4 0�w Revised July 14, 1996 N A L�%k 61SM6 Revised August 8, 1996 EXPtRES 8/27l Cjf3 J 1 TABLE OF CONTENTS Introduction: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Summary of Results: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Basin Summaries: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Detention Basin Design Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Water Quality: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Drainage Area Map: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 INTRODUCTION The following computations present the preliminary design of a stormwater detention system for the proposed Act III Theater Facility. The proposed 12.28 acre development, comprised of a 56,896 square foot theatre with 13 screens and 3,584 seats, is located on the west side of East Valley Highway, north of SW 41 st Street in the City of Renton. EXISTING DRAINAGE CONDITIONS The project site is presently a vacant parcel (Lot 3 of the Northern Railroad Binding Site Plan No. 014-92). The parcel was filled approximately 18 years ago. The existing ground cover consists mainly of grasses in poor condition over the fill material. The western portion of the parcel has several low areas identified during early project review as wetland areas with low functional values. The site generally drains from east to west to the wetland areas at an average slope of 0.25 percent. The runoff curve number and time of concentration for the pre developed condition were obtained from the preliminary drainage calculations, prepared by Bush, Roed and Hatchings in support of the site plan application for the Pace warehouse development (SP-005-92). A copy of the preliminary calculations has been provided at the end of this report. PROPOSED DRAINAGE CONDITIONS Runoff from the parking area in front of the proposed building will be conveyed in a storm drain pipe system to a grass-lined swale in the proposed wetland buffer at the rear of the building. The swale has been designed with a flat slope to promote water quality through ponding prior to discharge into the detention basin. The swale will outfall into the first of three water quality ponds. These ponds have been designed using the methodologies for a combined water quality / detention basin as outlined in the 1992 edition of the King County Stormwater Management (SWM) Manual. While the above mentioned grass lined swale will provide some water quality benefits, site constraints precluded the design of a bio-filtration swale meeting the requirements of the King County SWM Manual. To compensate for use of a smaller swale, additional storage has been provided in the proposed water quality ponds. Additional water quality storage has also been provided to compensate for paved areas downstream of the proposed facility. Calculations for pond surface area and volume are detailed on page 13 of this report. 1 The proposed detention basin has been designed to maximize the volume available for storage of excess storm water runoff while maintaining the hydrology of the existing and proposed wetland areas. The detention basin has been designed to release flows at or below the pre developed rates for the 2, 10, and 100 year storms per city of Renton standards. Detention storage has also been provided for development of Lots 4 and 6 of the Burlington Northern Binding Site Plan (BSP 014- 92), immediately south of the project site. The boundaries of the proposed drainage area tributary to the detention facility as well as limits of the bypass and off site areas are delineated on the drainage area map at the end of this report. The "Waterworks" program with the Santa Barbara Unit Hydrograph(SBUH)method and King County rainfall distribution (USER 1) was used in the design of the proposed facility. Control in the detention system will be provided by the following set inside of a 54 inch diameter catch basin manhole. • A 1 inch diameter orifice with an outlet elevation of 10.87 • A 3.5 inch diameter orifice with an outlet elevation of 15.00 • A 6 inch diameter elbow with an outlet elevation of 15.50 • An 15 inch diameter restrictor with an overflow elevation of 16.50 The control structure will discharge to a 15-inch storm drain pipe. The storm drain pipe will extend approximately 450 feet west to a connection with an existing 60-inch storm drain pipe on the west side of Lind Avenue. The 60-inch storm drain pipe continues approximately 1300 feet north, then 1,000 feet east to an outfall in Springbrook Creek. 2 SUMMARY OF RESULTS PROPOSED DETENTION SYSTEM Total Area of Project Site: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.28 Acres Less Bypass Area: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.60 Acres Less Bypass Area Tributary to Home Base Detention Basin: . . . . . . . . . . . . . . . . . . . 0.26 Acres Total Area of Project Site Tributary to Detention Basin: . . . . . . . . . . . . . . . . . . . . . 11.42 Acres Plus Offsite Wetland Mitigation Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.28 Acres Plus Mite Areas (Home Base and Ex. Warehouse): . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 Acres Plus Area of Lots 4 and 6 (BSP 014-92) Tributary to Detention Basin: . . . . . . . . . . . 1.52 Acres Total Area Tributary to Detention Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.23 Acres 1 YEAR STORM ()YATER QUALITY) Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N/A Peak Inflow to Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.17 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05cfs Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.01 Approximate Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,800 cf 2 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.66 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.53 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.55 cfs Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.61 Approximate Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52,800 cf 10 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.76 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.94 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.03 cfs Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.95 Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63,400 cf 100 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.28 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.66 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.37 cfs Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.38 Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85,300 cf 3 SUMMARY OF RESULTS HISTORY OF HYDROGRAPH ACTIVITY Date of Session: 8/8/96 11: 12:34 am LPOOL 1 "WATER QUALITY STORM" B1-WQ-1 B1-WQ-1 S-4 D-4 1 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume WATER QUALITY STORM 0.00 1. 17 S-4 D-4 14.01 0.05 1 14819. 61 cf LPOOL 2 "2 YEAR STORM" B1-EX2 Bl-DEV2 S-4 D-4 2 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 2 YEAR STORM 0. 66 4.53 S-4 D-4 15. 61 0.55 2 52822.37 cf LPOOL 3 "10 YEAR STORM" B1-EX10 B1-DEV10 S-4 D-4 3 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 10 YEAR STORM 1.76 6.94 S-4 D-4 15.95 1.03 3 63440.51 cf LPOOL 4 "100 YEAR STORM" B1-EX100 B1-DE100 S-4 D-4 4 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 100 YEAR STORM 3.28 9.66 S-4 D-4 16.38 1.37 4 85360. 08 cf 4 BASIN SUMMARIES 5 BASIN SUMMARIES PRE DEVELOPED CONDITIONS BASIN ID: B1-EX2 NAME: BASIN 1, EX. 2YR STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13.23 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERV IMP PRECIPITATION. . . . : 2.00 inches AREA. . : 13.23 Acres 0. 00 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81. 00 0. 00 TC. . . . : 60. 00 min 0. 00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 0.66 cfs VOL: 0. 67 Ac-ft TIME: 520 min BASIN ID: B1-EX10 NAME: BASIN 1, EX. 10YR STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13.23 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERV IMP PRECIPITATION. . . . : 2.90 inches AREA. . : 13.23 Acres 0. 00 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81. 00 0.00 TC. . . . : 60. 00 min 0.00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 1.76 cfs VOL: 1.36 Ac-ft TIME: 490 min BASIN ID: B1-EX100 NAME: BASIN 1, EX. 100YR STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13.23 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERV IMP PRECIPITATION. . . . : 3.90 inches AREA. . : 13.23 Acres 0. 00 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81. 00 0.00 TC. . . . : 60. 00 min 0.00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 3.28 cfs VOL: 2.25 Ac-ft TIME: 490 min 6 BASIN SUMMARIES POST DEVELOPED CONDITIONS BASIN ID: B1-WQ-1 NAME: BASIN 1, WATER QUALITY STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13.23 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERV IMP PRECIPITATION. . . . : 0.67 inches AREA. . : 2. 87 Acres 10.36 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81.00 98.00 TC. . . . : 39. 80 min 14. 85 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 190.00 ns:0.2400 p2yr: 2. 00 s: 0.0100 impTcReach - Sheet L: 20.00 ns:0.2400 p2yr: 2.00 s: 0. 0200 impTcReach - Sheet L: 50.00 ns:0.0110 p2yr: 2.00 s:0. 0120 impTcReach - Channel L: 990.00 kc:42.00 s:0.0038 impTcReach - Channel L: 165.00 kc: 17.00 s:0.0045 PEAK RATE: 1. 17 cfs VOL: 0.41 Ac-ft TIME: 480 min BASIN ID: B1-DEV2 NAME: BASIN 1, DEV. 2YR STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13.23 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERV IMP PRECIPITATION. . . . : 2.00 inches AREA. . : 2.87 Acres 10.36 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81.00 98.00 TC. . . . : 39. 80 min 14.85 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 190.00 ns:0.2400 p2yr: 2. 00 s: 0.0100 impTcReach - Sheet L: 20.00 ns:0.2400 p2yr: 2.00 s:0.0200 impTcReach - Sheet L: 50. 00 ns: 0. 0110 p2yr: 2. 00 s:0.0120 impTcReach - Channel L: 990.00 kc:42.00 s:0.0038 impTcReach - Channel L: 165.00 kc:17.00 s:0.0045 PEAK RATE: 4.53 cfs VOL: 1.68 Ac-ft TIME: 480 min BASIN ID: B1-DEV10 NAME: BASIN 1, DEV. 10YR STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13.23 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERV IMP PRECIPITATION. . . . : 2. 90 inches AREA. . : 2. 87 Acres 10.36 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81. 00 98. 00 TC. . . . : 39. 80 min 14. 85 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 190.00 ns:0.2400 p2yr: 2.00 s:0.0100 impTcReach - Sheet L: 20.00 ns:0.2400 p2yr: 2. 00 s:0.0200 impTcReach - Sheet L: 50.00 ns:0.0110 p2yr: 2. 00 s:0. 0120 impTcReach - Channel L: 990.00 kc:42. 00 s:0.0038 impTcReach - Channel L: 165.00 kc:17.00 s:0.0045 PEAK RATE: 6.94 cfs VOL: 2. 60 Ac-ft TIME: 480 min 7 BASIN ID: B1-DE100 NAME: BASIN 1, DEV. 100 YR STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13.23 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERV IMP PRECIPITATION. . . . : 3.90 inches AREA. . : 2. 87 Acres 10.36 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81.00 98. 00 TC. . . . : 39. 80 min 14.85 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 190.00 ns:0.2400 p2yr: 2.00 s:0. 0100 impTcReach - Sheet L: 20. 00 ns:0.2400 p2yr: 2. 00 s:0. 0200 impTcReach - Sheet L: 50.00 ns:0.0110 p2yr: 2.00 s:0. 0120 impTcReach - Channel L: 990.00 kc:42.00 s:0.0038 impTcReach - Channel L: 165. 00 kc:17. 00 s:0. 0045 PEAK RATE: 9.66 cfs VOL: 3. 65 Ac-ft TIME: 480 min g DETENTION BASIN DESIGN DATA 9 STAGE STORAGE TABLE CUSTOM STORAGE ID No. S-4 Description: PROPOSED DETENTION BASIN STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 13.00--- ==0.0000= 0.0000 =14.20 ===18550--- 0.9258 =15.40 46350 1.0 640 = 16.60= 97350 2.2348 13.10 1470 0.0337 14.30 20475 0.4700 15.50 49450 1.1352 16.70 102750 2.3588 13.20 2940 0.0675 14.40 22400 0.5142 15.60 52550 1.2064 16.80 108150 2.4B28 13.30 4410 0.1012 14.50 24325 0.5584 15.70 55650 1.2775 16.90 113550 2.6067 13.40 5880 0.1350 14.60 26250 0.6026 15.80 58750 1.3487 17.00 118950 2.7307 13.50 7350 0.1687 14.70 28175 0.6468 15.90 61850 1.4199 17.10 124350 2.8547 13.60 8820 0.2025 14.80 30100 0.6910 16.00 64950 1.4910 17.20 129750 2.9787 13.70 10290 0.2362 14.90 32025 0.7352 16.10 70350 1.6150 17.30 135150 3.1026 13.80 11760 0.2700 15.00 33950 0.7794 16.20 75750 1.7390 17.40 140550 3.2266 13.90 13230 0.3037 15.10 37050 0.8506 16.30 81150 1.8629 17.50 145950 3.3506 14.00 14700 0.3375 15.20 40150 0.9217 16.40 86550 1.9869 14.10 16625 0.3817 15.30 43250 0.9929 16.50 91950 2.1109 STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. 0-4 (USED IN DEVELOPMENT OF STAGE-DISCHARGE LIST D-2) Description: CATCH BASIN NO. 4A Outlet Elev: 10.87 Elev: 8.87 ft Orifice Diameter: 1.0000 in. Elev: 15.00 ft Orifice 2 Diameter: 3.5000 in. Elev: 15.50 ft Orifice 3 Diameter: 6.0000 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 10.87 0.0000 12.30 0.0325 13.80 0.0465 15.30 0.2392 10.90 0.0047 12.40 0.0336 13.90 0.0472 15.40 0.2680 11.00 0.0098 12.50 0.0346 14.00 0.0480 15.50 0.2935 11.10 0.0130 12.60 0.0357 14.10 0.0468 15.60 0.6255 11.20 0.0156 12.70 0.0367 14.20 0.0495 15.70 0.7747 11.30 0.0178 12.B0 0.0377 14.30 0.0503 15.80 0.8927 11.40 0.0198 12.90 0.0387 14.40 0.0510 15.90 0.9941 11.50 0.0215 13.00 0.0396 14.50 0.0517 16.00 1.0847 11.60 0.0232 13.10 0.0405 14.60 0.0524 16.10 1.1674 11.70 0.0247 13.20 0.0414 14.10 0.0531 16.20 1.2442 11.80 0.0262 13.30 0.0423 14.80 0.0538 16.30 1.3161 11.90 0.0275 13.40 0.0432 14.90 0.0545 16.40 1.3839 12.00 0.0288 13.50 0.0440 15.00 0.0552 16.50 1.4485 12.10 0.0301 13.60 0.0448 15.10 0.1609 12.20 0.0313 13.70 0.0457 15.20 0.2051 STAGE DISCHARGE TABLE DISCHARGE LIST ID No. D-4 Description: CATCH BASIN NO. 4A STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 13.00 0.0000 13.90 0.0489 14.80 0.0580 15.70 0.7700 13.10 0.0400 14.00 0.0500 14.90 0.0590 15.80 0.8733 13.20 0.0411 14.10 0.0510 15.00 0.0600 15.90 0.9767 13.30 0.0422 14.20 0.0520 15.10 0.1200 16.00 1.0800 13.40 0.0433 14.30 0.0530 15.20 0.1800 16.10 1.1600 13.50 0.0444 14.40 0.0540 15.30 0.2400 16.20 1.2400 13.60 0.0456 14.50 0.0550 15.40 0.2650 16.30 1.3200 13.70 0.0467 14.60 0.0560 15.50 0.2900 16.40 1.3850 13.80 0.0478 14.70 0.0570 15.60 0.5300 16.50 1.4500 10 WATER QUALITY 11 WATER QUALITY Reference: King County Surface Water Design Manual BIOFILTRATION Section 1.2.3 Core Requirement No. 3 Threashold for Biofiltration: Maximum Allowable Impervious Area Subject to Vehicular Traffic, A imp: . . . . . . . . . . . . . . . . . . 5,000 SF Proposed Condition: Total Impervious Area Subject to Vehicular Traffic, Aimp: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290,400 SF Biofiltration is required. Because of constraints on site grading, the surface area proposed in the grass-lined swale outfall to the water quality ponds does not meet the design standards outlined in the manual. In order to compensate for the loss of biofiltration area, the proposed wetponds have been enlarged to provide additional surface area and storage volume. The calculations for the proposed wetponds are presented on the following page. 12 SPECIAL WATER QUALITY CONTROLS Section 1.3.5 Special Requirement No. 5 As outlined in the introduction, the proposed detention system outfalls to an existing storm drain pipe system in Lind Avenue for eventual discharge into Springbrook Creek, a Class 2 stream. Since the project site proposes discharge within a one mile radius of a Class 2 Stream, a wetpond is required. The engineering plans propose a three cell combination wetpond - detention basin. Since the surface area of the proposed grass lined swale could not meet the requirements outlined in the SWM Manual, additional surface area and storage volume has been proposed in the wetponds. As shown in the following calculations, the proposed wet ponds provide over four times the required wetpond surface area and over two time the required wetpond storage volume. This additional surface area and storage volume is intended to compensate for the limited surface area in the proposed grass lined swale. WETPOND DESIGN Required Water Surface Area, Awq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3,496 SF Awq = One Percent of Impervious Area Impervious Area, Aimp: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349,600 SF Act III Project: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290,400 SF Lots 4 and 6 (BSP 014-92): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50,000 SF Access Driveway to Lind Avenue: . . . . . . . . . . . . . . . . . . . . . . . . . 9,200 SF Proposed Water Surface Area, Awq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,900 SF Ratio of Proposed Water Surface Area to Required Water Surface Area: . . . . . . . . . . . . . . . . . . 3.40 Section 1.3.5(2) Storage Volume Required Storage Volume, Vwq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17,775 CF Vwq = Total Volume of Runoff from the Mean Annual Storm Vwq = 0.408 Acre-Feet x 43,560 (See Page 4 for Storm Routing) Total Drainage Area, A: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.48 Acres Act III Project: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.71 Acres Lots 4 and 6 (BSP 014-92): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.52 Acres Access Driveway to Lind Avenue: . . . . . . . . . . . . . . . . . . . . . . . . 0.25 Acres Proposed Storage Volume, Vwq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27,350 CF Ratio of Proposed Storage Volume to Required Storage Volume: . . . . . . . . . . . . . . . . . . . . . . . 1.54 The volume calculations for the proposed wetponds are presented on the following page. 13 8/8/96 1:13 PM WATER QUALITY PONDS VOLUME CALCUALTIONS POND NO. 1 WS Area Avg. Area Depth Inc. Volume Total Volume Elevation Square Feet Square Feet Feet Cubic Feet Cubic Feet 10.00 3,500.00 0.00 3,850.00 1.00 3,850.00 11.00 4,200.00 3,850.00 5,050.00 2.00 10,100.00 13.00 5,900.00 13,950.00 POND NO. 2 WS Area Avg. Area Depth Inc. Volume Total Volume Elevation Square Feet Square Feet Feet Cubic Feet Cubic Feet 10.00 2,500.00 0.00 2,800.00 1.00 2,800.00 11.00 3,100.00 2,800.00 3,750.00 1 2.00 7,500.00 13.00 4,400.00 1 1 1 10,300.00 POND NO. 3 WS Area Avg. Area Depth Inc. Volume Total Volume Elevation Square Feet Square Feet Feet Cubic Feet Cubic Feet 10.00 600.00 0.00 700.00 1.00 700.00 11.00 800.00 700.00 1,200.00 1 2.00 1 2,400.00 13.00 1,600.00 1 1 1 1 3,100.00 Total Surface Area Provided:................................................................................ 11,900.00 Square Feet Total Volume Provided:........................................................................................ 27,350.00 Cubic Feet 14 WQSTOI.XLS COALESCING PLATE OIL/WATER SEPARATORS Section 1.3.6 Special Requirement No. 6 Threashold for Coalescing Plate Oil/Water Separators Maximum Allowable Impervious Area Subject to Vehicular Traffic, A imp: . . . . . . . . . . . . . . . . . 5.00 Acres Maximum Number of Vehicle Trips Per Day: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,500 Trips Proposed Condition: Total Impervious Area Subject to Vehicular Traffic, Aimp: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.67 Acres Proposed Number of Vehicle Trips Per Day: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,272 Trips See page 15 of the Traffic Impact Analysis for the proposed theatre project (copy attached). 15 05/31/96 11:00 FAX 206 747 3688 TRANSPO Group Z 002 Traffic Impact Analysis for Act lil's East Valley Cinema December 15. 1995 Table 4, Project Trip Generation Daily Trips Peak Month Peak Wlon.-h Peak-Month Avg Month Size Mon-Thur' Friday' Avg Weekday' Avg Weekday' Cinema 3,584seats 1,900 2.903 2,100 1,272 Friday Peak Hour Trips Paak Month Peak Month PM Peak Hour Theater Peak Hour 4:30--5:30 .rn•); (74 pin.)' Size n out Total in Out Total Cinema 3,584 seats 148 67 215 444 309 753 1 BaseC on average customerlicker data from ju'y 1 io 14, 1995. 2 A4 sfed based on a weigrted average of Monday to Friday conojons. — 3 Adlusled based an average monthly kcketsales data MO kiyticket sales represenb'ng J3.76%of the yearly sales. Project Trip Distribution and Assignment The trip distribution in the Pace Warehouse study were based on the travel fore- casting model developed by TRANSPO for the ✓a11ey Transportation Benefit Assessment Dis- trict analysis. To derive the trip distribution for the cinema project, the Pace Warehouse distribution was adjusted based on the taaffie patterns associated :with the surrounding street system and review of population and employment in and around the area. The resulting trip distribution for the Renton Bast Valley Cinema is shown on Figure 7. Forty(40) percent of the project traffic would be oriented to the north via Lind Avenue SW, E Valley Road, and SR 167, .Another 15 percent would be oriented west via SW 43rd Street Approximately 35 percent would be oriented to area,5 south of the project site via E Valley Road and SR 167. The remaining 10 percent would be oriented to and from the east via SW 43rd Street. The project-generated trips were assigned to the vicinity sweet system based on the distribution pattern, local travel patterns in the area. and the location of project driveways. The resulting assignment is shown in Figure 8. Sixty-eight(68) percent of the project traffic was assigned to the two driveways on E Valley Road, while 25 percent of the project traffic was assigned to the driveway on SW 41st Street. The remaining 7 percent was assigned the proposed access driveway on Lind Avenue SW. Traffic Volumes The project-generated.traffic aras added to the 1996 baseline traffic volumes without the project to produce traffic volumes for 1996 with-project conditions during the weekday PM peals hour_ Additionally, since the proposed project would add an access road from the site to Lind Avenue SW, a redistribution of HorneBase trips was also incorporated into the 1996 with-project trafi'ic conditions. The resulting weekday PY peak hour volumes are shown on Figure 9. A comparison of project traffic to total trade at study area intersections is presented in Table 5. 95351,001AS195331RY the TRANSPO Group,lne. Page 15 DRAINAGE AREA MAP 17 + I I I SITE AREA TRIBUTARY TO HOME BASE DETENTION BASIN SITE AREA TRIBUTARY TO HOME BASE DETENTION BASIN AREA = 0.15 ACRES AREA = 0.11 ACRES OFF SITE AREA TRIBUTARY TO BASIN - BINDING r N a xN a$IINDs�r¢�BETE ava.ata$®m marmII.atsaa$®aa N®mu°a'emadx AREA = 0.002 ACRES m8T NO.OH-Be a m:LIIOTIIIId?d�®ffim mi®m I I I I I I � I I I Ig } tpP laa DrN-a> EX.FIRE HWRANT A N DRAINAGE DIVIDE °"Y"I € E STNG BERM--} SBB'09'S1'E-875.52 IX CB J I I DUSTING WETLAND AREA I EKS CO WO a 1•a fla M NCRETE PAD �. _.. ��. - .... ,,.' � Y CB N0.26 CB NO.27 [� I Y Y ',�, .,• o- � 1 �D6� •�_ • -12"P SD II'-12�PVC SD 93'-12"PVC SD EK 12" •�YATGiN�N•, ' ,'�. / EXISTING BERN ,•iY-12[e9C 6 •T8• k-=-+-[ W II• •--•-�: ••Z. i --20 [xlAuw IIr®9P R OUTTALL N0.25A � 2 • , f W mIIIYIIDIIrsaa®88'm]P&AlB 1!°®m I � ;� ; 1 -- `_ •• •••• IXYCBMH o I SDCO NO.37 sop NO ®ll�-BA .. RIM_21.90 a fcoz sD °gf`°?•P �' .1 ai Z 19'-GRASS NEB V"1&6Q-18 37 SMILE a 0.54E 2_6'PVC ROOF R. ,90 I •� W DRAINAGE DIVIDE DRAINS.2.DDE mm- SEE PLUMBING PI 4N NiV 1.20 10 (xo xmne FOR CWTNUATDN 2]'-B'PVC D e 222E CB NO.29 / OUTFALL N0,24C I CONCRETE PAD FOR [I•'.� 8' pta.l f.,4 M1 DR E( PROPOSED_,N BERM TRUCK LOADING (t1Y u 17-12'PVC 50 SEE ARCMTECIURK 6 IY Y TOP_i].50 CB NO. 4B PLAN FOR DETAILS SDCO NO.37 �i BYPASS AREA = 0.45 ACRES RIM.21.40 (/ 2e'WETLAND BUFFER I 182'-127VC SD tlg'-12'PVC SD 526'33'S1•W-21e.)0' lu'-{'PVC SD O I.SDE gy IX ca Y7W / / Te'-rrovc m a 2.0aE / p a:Grp 39TH ( CB NO,30� I SEE PLUMBING PLAN FOR CONTNUATON 4 ACCESS TO WATER DN/4Itt POND '• 1 OF ROOF GRAIN IN EARIDING 'O SEE DETAII.SHEET 9 [X awa W gRRR / CB N0.1 WATER DUALITY POND NO.3 17-1 - [NK q�RoasWUK O+SOt6-21.16 T. CB NO. 24 �Q75 1 g INTAKE N0.4H ` •' , ••'� 1aW, do ¢a ;�1} 1[Xo /22'-12'PVC S • /1Pp10 DRAM) 1 f' •y w I n1 arm aD OUTFALL NO.4GOUTFALLTO.24 t B$ " r ¢mTIIiYYww,�T SDCO N0. 36 STREETS ryj BYPASS AREA = 0.04 ACRES I� } ~U " RBA 22DG EX.GON«,E,EPADLSTR MT ��11 j ^tYCP SD I` 1 I Q h INN.19.60 LIGHT TO BE RElOC TED. X [.v.,YnTRc aaiW �I6 � � 5'CONC.SIDEWALK �1 I ( y tgq-12'PVC SD fl 116•-12'PVC SD MD(I� WATER DUALITY 131'GRASS LINED ••. SEE ARCMTEMRAL PLANS `PP\ POND NO 2 SWAlE e 1 5]E FOR DETAILS OF IS PLAN S•iB_.S�$�]Z/ y 1 ° 3 l CB NO.2 - R 1]'-tYPYC SO CONCRETE PAD FOR t+DD.DD-ON D.L INTAKE N0.4F / C NO.14 ' `� SEE A LOADING L B z '! / • ILMAL 25'-12'PVC SD - SEE OFOR DETAILS C AILS (POND DRAM) OUTFALL ' PLPN FOR DETALS yy JC D• 2-AM ROCP SEE PLU BIND PUN Ir1 •IIr,' g W �' • DRAINS a 200E FOR TON •.�-�+1 'O M1O 0 / W 33p a ltl �♦\ °a l4'-tarosc sD D OUTFALL N0. 4 m 19'-8"PVC SO 1POND GRAIN 28'-e"PVC SD a 2.00E R 1a'-1s'PNt;SD(OrT3enowl SOLO NO.34 SD 0 NO.33 I1�--'-III L •4D J O y WATER AUTV POND N0.1 RIM_21,80 RIM.21.90 ••l�J, \ J 1 WV_16.06 INN 15.50 \ J / IX.CB I If • _MR I N1- 5 GONC IWALA- 1 ' :( f• CB NO. 16LIM r / 6 91'-12'PVC SD V 167 12'PVC SD I ' 3+00.00-ON C. f/1 �01 1D Ce42_12'PVC ?0e0'-1•vvc m r5'-e'Pvc s0 a 200z CB N0.10 CB N0. 11,-12"CP 5D188'-12'PVC SDya 4 PR__ 114==I�PVC NA1' ernW \0 _= SBB'06'2°'E=391.2Y ---_ -- I Y�H iowarF°f ■///,� __ 16 InILVB / 16 Nfi8Va26�1� O //V O \ °g 9aNc txr.f 18 \ 10I 0 146 E%CBMH CB NO. 4 a[vs NwrAR 1Y-12'PVC SD k` 0 Lu 4+10.00-10.15 RT. 150'-SHALLOW ALE a 1.00E CB N0.6 6+ N0.7 CB N0.9 INTAK N t0A 5W N I INTAKE N0.4B 5+11.3fi-11.19 RT. SEE CETNL.spEET° CB N0.18 4+4J.98-34.90 LT. 6+02°1-11.i D'RT, q Y CB N0.4A 5+611 Ja-J5.19 LT. / 169'--112'PVC SO 1 P2-VC 59 ACCESS TO WATER WAUtt P0e0 Y INTAKE NO.4D SEE DETAIL SHEET 4 N01'S0'12•E-20,00' 1° =1B 15'-12RVC 6° 160'-12'PVC 50 pggHtL 8 a+5 Se.0.Te- 4e'LT. CB NO. 78 to :a YNI s01'S0'17w-9a.n• INTAKE N0.18A ° INTAKE N0, 40 6+02.63-31.I9Yf T. Nsa•JY;]•w..1°6.vp 0. Tv w .117 '3�oPr'-16a sT H59.49-45.34 T. __� C_____ EX. ONE STORY CONCRETE BUILDING 200 sHAuow swAEel.00E BYPASS AREA = 007 ACRES n. � \\�DDETAIL,9HEIT e . DEVELOPED OFF SITE AREA BYPASSING BASIN = 0.25 ACRES DRAINAGE DIVIDE OFF SITE AREA TRIBUTARY TO BASIN AREA = 0.005 ACRES \\\ VC SID iaR�x�RN .®T a Y9 1 rF EX WATER MH EG^t ••. ••� r TOTAL AREA OF PROJECT SITE:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12.28 ACRES I LESS BYPASS AREA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.60 ACRES e �® LESS BYPASS AREA TRIBUTARY TO HOME BASE DETENTION BASIN. . . . . . . . . . . 0.26 ACRES SaB'J]'0]'E'16.66' g Sea O)'O E-tOS.eY Ys a� EX CBNH TOTAL AREA OF PROJECT SITE TRIBUTARY TO DETENTION BASIN . . . . . . . . . . . . 11.42 ACRESoom KaMY.B a o- • � F PLUS OFFSITE WETLAND MITIGATION AREA. . . . . . . . . . . . . . . 0.28 ACRES W aPAnaOa PLUS OFFSITE AREAS (HOME BASE AND EX. WAREHOUSE). 0.01 ACRES �- B NIT F.N,a P[ b 589'49Y5'W 39.11' PLUS AREA OF LOTS 4 AND 6 (BSP 014-92) TRIBUTARY TO DETENTION BASIN. . . . 1.52 ACRES LOT 6 AREA ( .76 ACRES DRAINAGE AREA MAP TOTAL AREA TRIBUTARY TO DETENTION BASIN. . . . . . . . . . . . . . . . . . . . . . . .13.23 ACRES a"°"'� ' BYPASS AREA = 0.04 ACRES FOR LOT 4 (BSP 014-92) ACT 111 THEATERS S. W. 41 S T STREET AREA = 0.76 ACRES SCALE: 1' = 100' FOR DISTRIBUTION TO: a'` Water Utility ® Building Division IEli ji W a tewater Utility Public Works Constr Inspector Surface Water Utility Fire Prevention '�r!3 Maintenance Scrvlces rz� Transportation Systcros Projecr: Aor -t# L Q7 Ll Location: -3751 kas-r V�3G.r�`L QDA Attached please Find copies or: (v9 PERMIT ® BILLS OF SA LE E RECEIPT ® COST DATA INVENTORY t.�.I LETTER OF SPECIAL BILLING - ® EASEMENT(S) rt STUB SERVICE AGREEMENT ® COPY OF AS-BUILT PRECON NOTES PRECON ATTENDEES DRAINAGE REPORT t MEMO - WATER BREAKDOWN MAP WITH NEW MAINS AND VALVES O"1.HER From: _--c)_�',�' I,7 7:f)`coH:o15Tr SUMMARY OF RESULTS PROPOSED DETENTION SYSTEM - Total Area of Project Site: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.28 Acres Less Bypass Area: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.60 Acres Less Bypass Area Tributary to Home Base Detention Basin: . . . . . . . . . . . . . . . . . . . 0.26 Acres Total Area of Project Site Tributary to Detention Basin: . . . . . . . . . . . . . . . . . . . . . 11.42 Acres Plus Offsite Wetland Mitigation Area: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.28 Acres Plus Offsite Areas (Home Base and Ex. Warehouse): . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 Acres Plus Area of Lots 4 and 6 (BSP 014-92) Tributary to Detention Basin: . . . . . . . . . . . 1.52 Acres Total Area Tributary to Detention Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.23 Acres 1 YEAR STORM (WATER QUALITY) Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N/A Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.17 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05cfs I.14C s Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.01 5,710 Approximate Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14180a cf 0,520 C� 2 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.66 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.53 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ff-55-cfs '.9I Cfs Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +5-.61 14.95 Approximate Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52;800 cf ?�z,1g9 rsf 10 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.76 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.94 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-:03 cfs t.51 GFs Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5.95 15.51 Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631400-cf- 4'1,953 CF 100 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.28 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.66 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4-7-efe 1.68 GFS Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16:38 16.12. Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83;30G of 8,855 cf 3 SUMMARY OF RESULTS PROPOSED DETENTION SYSTEM RENJ ISED DESIGN Total Area of Project Site: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.28 Acres Less Bypass Area: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.60 Acres Less Bypass Area Tributary to Home Base Detention Basin: . . . . . . . . . . . . . . . . . . . 0.26 Acres Total Area of Project Site Tributary to Detention Basin: . . . . . . . . . . . . . . . . . . . . . 11.42 Acres Plus Offsite Wetland Mitigation Area: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.28 Acres Plus Offsite Areas (Home Base and Ex. Warehouse): . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 Acres Plus Area of Lots 4 and 6 (BSP 014-92) Tributary to Detention Basin: . . . . . . . . . . . 1.52 Acres Total Area Tributary to Detention Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.23 Acres 1 YEAR STORM (WATER QUALITY) Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N/A Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.17 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .fl.05cfs O.OG cis - Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.0-1-13.98 Approximate Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,800 cf :4,415 C� 2 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.66 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.53 cfs Proposed Release Rate: 0.55 cfs `.66 cfs Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5.61 '5,22 Approximate Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52,800 cf %13,384C� 10 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.76 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.94 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.03 cfs '.0 1 CFZ Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.95 Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63, W-cf 56,198 C� 100 YEAR STORM Peak Discharge for Pre Developed Conditions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.28 cfs Peak Inflow to Basin: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.66 cfs Proposed Release Rate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.37 c€s- 1.53 CFS Design Water Surface Elevation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.38 Volume of Storage Provided: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85,300 cf '31103 Cf' 3 ACT III THEATRES - RENTON --------------------------------------------------------------------- --------------------------------------------------------------------- HISTORY OF HYDROGRAPH ACTIVITY Date of Session: 4/30/97 1:28:33 pm AS-BUILT LPOOL 1 "WATER QUALITY STORM" Bl-WQ-1 B1-WQ-1 S-4 (AB) D-4 (AB) 1 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume WATER QUALITY STORM 0.00 1.17 S-4(AB) D-4 (AB) 13.70 0.14 1 10321.46 cf LPOOL 2 "2 YEAR STORM" Bl-EX2 B1-DEV2 S-4(AB) D-4(AB) 2 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 2 YEAR STORM 0.66 4.53 S-4 (AB) D-4(AB) 14.95 0.81 2 32199.03 cf LPOOL 3 "10 YEAR STORM" B1-EX10 Bl-DEV10 S-4 (AB) D-4 (AB) 3 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 10 YEAR STORM 1.76 6.94 S-4 (AB) D-4 (AB) 15.51 1.31 3 47953.41 cf LPOOL 4 "100 YEAR STORM" B1-EX100 B1-DE100 S-4 (AB) D-4 (AB) 4 Description . MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 100 YEAR STORM 3.28 9.66 S-4(AB) D-4 (AB) 16.12 1.68 4 68855.18 cf REVISED DESIGN LPOOL 1 "WATER QUALITY STORM" B1-WQ-1 B1-WQ-1 S-4 (AB) D-4 (REV) 1 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume WATER QUALITY STORM 0.00 1.17 S-4 (AB) D-4 (REV) 13.98 0.06 1 14415.67 cf LPOOL 2 "2 YEAR STORM" Bl-EX2 B1-DEV2 S-4 (AB) D-4 (REV) 2 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 2 YEAR STORM 0.66 4.53 S-4 (AB) D-4 (REV) 15.22 0.68 2 39384.32 cf LPOOL 3 "10 YEAR STORM" Bl-EX10 Bl-DEV10 S-4 (AB) D-4 (REV) 3 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 10 YEAR STORM 1.76 6.94 S-4 (AB) D-4 (REV) 15.81 1.07 3 56798.35 cf LPOOL 4 "100 YEAR STORM" B1-EX100 Bl-DE100 S-4 (AB) D-4 (REV) 4 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 100 YEAR STORM 3.28 9.66 S-4(AB) D-4 (REV) 16.38 1.33 4 83103.18 cf ACT III THEATRES - RENTON --------------------------------------------------------------------- --------------------------------------------------------------------- STAGE STORAGE TABLE CUSTOM STORAGE ID No. S-4 (AB) Description: AS BUILT DETENTION BASIN STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- ------------ ----------------------------------------------------------------------------------------------------- 13.00 0.0000 0.0000 14.20 18406 0.4225 15.40 44798 1.0284 16.60 94739 2.1749 13.10 1474 0.0338 14.30 20239 0.4646 15.50 47730 1.0957 16.70 100131 2.2987 13.20 2948 0.0677 14.40 22072 0.5067 15.60 50662 1.1630 16.80 105522 2.4225 13.30 4422 0.1015 14.50 23905 0.5488 15.70 53594 1.2303 16.90 110914 2.5462 13.40 5896 0.1354 14.60 25738 0.5909 15.80 56526 1.2977 17.00 116305 2.6700 13.50 7370 0.1692 14.70 27571 0.6329 15.90 59458 1.3650 17.10 121697 2.7938 13.60 8844 0.2030 14.80 29404 0.6750 16.00 62390 1.4323 17.20 127088 2.9175 13.70 10318 0.2369 14.90 31237 0.7171 16.10 67782 1.5560 17.30 132480 3.0413 13.80 11792 0.2707 15.00 33070 0.7592 16.20 73173 1.6798 17.40 137871 3.1651 13.90 13266 0.3045 15.10 36002 0.8265 16.30 78565 1.8036 17.50 143262 3.2889 14.00 14740 0.3384 15.20 38934 0.8938 16.40 83956 1.9274 14.10 16573 0.3805 15.30 41866 0.9611 16.50 89348 2.0511 ACT III THEATRES - RENTON --------------------------------------------------------------------- --------------------------------------------------------------------- AS-BUILT STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. 0-4 (AB) USED TO DEVELOP STAGE-DISCHARGE LIST D-4 Description: CATCH BASIN NO. 4A AS BUILT Outlet Elev: 10.72 Elev: 8.72 ft Orifice Diameter: 1. 0000 in. Elev: 13. 81 ft Orifice 2 Diameter: 3.5000 in. Elev: 14.81 ft Orifice 3 Diameter: 6. 0000 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- ------------- ------ 10.72 0.0000 12.30 0.0341 13.90 0.1481 15.50 1.3030 10.80 0.0077 12.40 0.0352 14.00 0.1940 15.60 1.3730 10.90 0.0115 12.50 0.0362 14.10 0.2289 15.70 1.4392 11.00 0.0144 12.60 0.0372 14.20 0.2582 15.80 1.5021 11.10 0.0167 12.70 0.0382 14.30 0.2840 15.90 1.5623 11.20 0.0188 12.80 0.0391 14.40 0.3074 16.00 1.6200 11.30 0.0207 12.90 0.0401 14.50 0.3289 16.10 1.6756 11.40 0.0224 13.00 0.0410 14.60 0.3489 16.20 1.7292 11.50 0.0240 13.10 0.0419 14.70 0.3678 16.30 1.7812 11.60 0.0255 13.20 0.0427 14.80 0.3856 16.40 1.8315 11.70 0.0269 13.30 0.0436 14.90 0.6956 16.50 1.8805 11.80 0.0282 13.40 0.0444 15.00 0.8446 16.60 1.9281 11.90 0.0295 13.50 0.0452 15.10 0.9605 16.70 1.9745 12.00 0.0307 13.60 0.0461 15.20 1.0595 16.80 2.0199 12.10 0.0319 13.70 0.0468 15.30 1.1477 16.90 2.0642 12.20 0.0330 13.80 0.0476 15.40 1.2283 17.00 2.1075 AS-BUILT STAGE DISCHARGE TABLE DISCHARGE LIST ID No. D-4 (AB) Description: CATCH BASIN NO. 4A AS BUILT STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- ------ -- ------------------------------------------------- 13.00 0.0000 13.90 0.1733 14.60 0.7100 15.70 1.4400 13.10 0.0400 14.00 0.1900 14.90 0.7750 15.80 1.5000 13.20 0.0567 14.10 0.2550 15.00 0.8400 15.90 1.5600 13.30 0.0733 14.20 0.3200 15.10 0.9433 16.00 1.6200 13.40 0.0900 14.30 0.3850 15.20 1.0467 16.10 1.6733 13.50 0.1067 14.40 0.4500 15.30 1.1500 16.20 1.7267 13.60 0.1233 14.50 0.5150 15.40 1.2250 16.30 1.7800 13.70 0.1400 14.60 0.5800 15.50 1.3000 16.40 1.8300 13.80 0.1567 14.70 0.6450 15.60 1.3700 16.50 1.8800 ACT III THEATRES - RENTON --------------------------------------------------------------------- --------------------------------------------------------------------- REVISED DESIGN STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. 0-4 (REV) USED TO DEVELOP STAGE-DISCHARGE LIST D-4(REV) Description: CATCH BASIN NO. 4A REVISED Outlet Elev: 10.72 Elev: 8.72 ft Orifice Diameter: 1. 0000 in. Elev: 13.81 ft Orifice 2 Diameter: 1. 0000 in. REDUCED ORIFICE Elev: 14. 81 ft Orifice 3 Diameter: 6. 0000 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---Cfs-- ------- -------------------------------------------------------------------------------------------------------- - ----- ------- --------- ------------------------------- ------------------------ 10.72 0.0000 12.30 0.0341 13.90 0.0565 15.50 0.9061 10.80 0.0077 12.40 0.0352 14.00 0.0610 15.60 0.9646 10.90 0.0115 12.50 0.0362 14.10 0.0645 15.70 1.0195 11.00 0.0144 12.60 0.0372 14.20 0.0676 15.80 1.0715 11.10 0.0167 12.70 0.0382 14.30 0.0703 15.90 1.1209 11.20 0.0188 12.80 0.0391 14.40 0.0729 16.00 1.1682 11.30 0.0207 12.90 0.0401 14.50 0.0753 16.10 1.2136 11.40 0.0224 13.00 0.0410 14.60 0.0776 16.20 1.2573 11.50 0.0240 13.10 0.0419 14.70 0.0797 16.30 1.2994 11.60 0.0255 13.20 0.0427 14.80 0.0818 16.40 1.3402 11.70 0.0269 13.30 0.0436 14.90 0.3769 16.50 1.3798 11.80 0.0282 13.40 0.0444 15.00 0.5116 16.60 1.4182 11.90 0.0295 13.50 0.0452 15.10 0.6137 16.70 1.4556 12.00 0.0307 13.60 0.0461 15.20 0.6995 16.80 1.4920 12.10 0.0319 13.70 0.0468 15.30 0.7751 16.90 1.5275 12.20 0.0330 13.80 0.0476 15.40 0.8433 17.00 1.5622 REVISED DESIGN STAGE DISCHARGE TABLE DISCHARGE LIST ID No. D-4 (REV) Description: CATCH BASIN NO. 4A REVISED STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- ---------------------- ------------------------------------------------------------------------------------------- 13.00 0.0000 13.90 0.0578 14.80 0.0800 15.70 1.0200 13.10 0.0400 14.00 0.0600 14.90 0.2950 15.80 1.0700 13.20 0.0422 14.10 0.0625 15.00 0.5100 15.90 1.1200 13.30 0.0444 14.20 0.0650 15.10 0.5880 16.00 1.1700 13.40 0.0467 14.30 0.0675 15.20 0.6660 16.10 1.2133 13.50 0.0489 14.40 0.0700 15.30 0.7440 16.20 1.2567 13.60 0.0511 14.50 0.0725 15.40 0.8220 16.30 1.3000 13.70 0.0533 14.60 0.0750 15.50 0.9000 16.40 1.3400 13.80 0.0556 14.70 0.0775 15.60 0.9600 16.50 1.3800 SPECIAL WATER QUALITY CONTROLS Section 1.3.5 Special Requirement No. 5 As outlined in the introduction, the proposed detention system outfalls to an existing storm drain pipe system in Lind Avenue for eventual discharge into Springbrook Creek, a Class 2 stream. Since the project site proposes discharge within a one mile radius of a Class 2 Stream, a wetpond is required. The engineering plans propose a three cell combination wetpond - detention basin. Since the surface area of the proposed grass lined swale could not meet the requirements outlined in the SWM Manual, additional surface area and storage volume has been proposed in the wetponds. As shown in the following calculations, the proposed wet ponds provide over four times the required wetpond surface area and over two time the required wetpond storage volume. This additional surface area and storage volume is intended to compensate for the limited surface area in the proposed grass lined swale. WETPOND DESIGN Required Water Surface Area, Awq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3,496 SF Awq= One Percent of Impervious Area Impervious Area, Aimp: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349,600 SF Act III Project: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290,400 SF Lots 4 and 6 (BSP 014-92): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50,000 SF Access Driveway to Lind Avenue: . . . . . . . . . . . . . . . . . . . . . . . . . 9,200 SF 18,snocys Proposed Water Surface Area, Awq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -iri;900-8B- Ratio of Proposed Water Surface Area to Required Water Surface Area: . . . . . . . . . . . . . . . . . . 3 A-G 3.2s Section 1.3.5(2) Storage Volume Required Storage Volume, Vwq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : . . . . I . . . . 17,775 CF Vwq=Total Volume of Runoff from the Mean Annual Storm Vwq =0.408 Acre-Feet x 43,560 (See Page 4 for Storm Routing) Total Drainage Area, A: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.48 Acres Act III Project: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.71 Acres Lots 4 and 6 (BSP 014-92): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.52 Acres Access Driveway to Lind Avenue: . . . . . . . . . . . . . . . . . . . . . . . . 0.25 Acres 2c,4=n-F Proposed Storage Volume, Vwq: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27,350 CP- Ratio of Proposed Storage Volume to Required Storage Volume: 1.54 1.49 The volume calculations for the proposed wetponds are presented on the following page. 13 5/11/97 9:35 AM ACT HI THEATRES WATER QUALITY PONDS AS BUILT VOLUME CALCUALTIONS POND NO. 1 WS Area Avg. Area Depth Inc. Volume Total Volume Elevation Square Feet Square Feet Feet Cubic Feet Cubic Feet 10.00 3,230.00 0.00 3,625.00 1.00 3,625.00 11.00 4,020.00 3,625,00 4,910.00 2.00 9,820.00 13.00 5,800.00 1 1 13,445.00 POND NO. 2 WS Area Avg. Area Depth Inc. Volume Total Volume Elevation Square Feet Square Feet Feet Cubic Feet Cubic Feet 10.00 2,530.00 0.00 2,820.00 1.00 2,820.00 11.00 3,110.00 2,820.00 3,780.00 2.00 1 7,560.00 13.00 4,450.00 10,380.00 POND NO. 3 WS Area Avg. Area Depth Inc. Volume Total Volume Elevation Square Feet Square Feet Feet Cubic Feet Cubic Feet 10.00 510.00 0.00 615.00 1.00 615.00 11.00 720.00 615.00 985.00 2.00 1,970.00 13.00 1 1,250.00 1 2,585.00 Total Surface Area Provided:................................................................................ 11,500.00 Square Feet Total Volume Provided:........................................................................................ 26,410.00 Cubic Feet 14 WQABo 1.XLS 5/11/97 9:42 AM DETENTION BASIN AS BUILT VOLUME CALCUALTIONS WS Area Avg. Area Depth Inc. Volume Totfil Volume Elevation Square Feet Square Feet Feet Cubic Feet Cubic Feet 13.00 14,320.00 0.00 15,365.00 1.00 15,365.00 14.00 16,410.00 15,365.00 18,330.00 1.00 18,330.00 15.00 20,250.00 33,695.00 29,320.00 1.00 29,320.00 16.00 38,390.00 63,015.00 53,915.00 1.50 80,872.50 17.50 69,440.00 1 1 1 143,887.50 Total Volume of Storage Per Design:.................................................................... 145,950.00 Total Volume of Storage As Built:........................................................................ 143,887.50 DEABOI.XLS 25 5/11/97