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HomeMy WebLinkAboutSWP272217 Short Plat (SHPL# ) REQUEST FOR PROJECT# Prelim.Plat (PP# -O ) CAG# ) 711,214 2— To: Technical Services Date WO# / Green# From: Plan Review/Project Manager Project Name (70 characters max) D cription of Project: Circle Size of Waterline: / 8% / 1(y 12" Circle One: e or Extension Circle Size of Sewerline: 8" IV 12" Circle One: ew or Extension Circle Size of Stormline: 12" 15" 18" 24" Circle One: 1.11 ew or Extension (� Dvlpr/Contractor/Owner/Cnsit:: > (70 characters max) Check each discipline involved in Project Ltr Drwg #of sheets per discipline t,- Trans-storm VYA 41,J �� 1❑ , r,? 3 adway/Dminage) (Off sito impmvements)(indude basin name) ee (includel'ESC�[-) Transportation /(SignalizatiorL Channeluat on lighting) Q/ Wastewater F ll, 9knitary Sewv Main(include basin name) CY Water (Mains.valves.Hydrants) 3 S- '(lndude composite&Horizontal Sheets) ❑ Suface Water ❑ ❑ Improvements (CIP ONLY)(include basin name) TS Use Only a�r7 T- 2217 IdOf- K - 2 17 5 - 3�f7 r�iA - a)- �4 7 Approved by TSM 5 � -7 Date: � ( H:romututility/92-090.DOC/CDlbh vras CITY OF RENTON PLANNING/BUILDING/PUBLIC WORKS MEMORANDUM DATE: July 11, 1995 TO: DAVE CHRISTENSEN CON LYS HORNSBY JACK CRUMLEY BOB MAHN f FROM: ARNETA H. X6198 A J I/ SUBJECT: VILLAGE ON UNION NE 6TH ST & UNION AVE NE THE ATTACHED PLANS ARE ALMOST READY FOR FINAL APPROVAL, AND I WILL BE REQUESTING THE FINAL MYLARS. IF YOU HAVE ANY COMMENTS ON THESE PLANS, PLEASE RETURN THEM TO ME BY 10 AM JULY \-V . IF NO RESPONSE IS RECEIVED BY THIS DATE, I WILL ASSUME THERE ARE NO SUBSTANTIAL OBJECTIONS TO THE PLANS AND WILL PROCEED WITH PROJECT APPROVAL. 'DO NOT MARK ON THESE PLANS. IF YOU NEED A SET YOU MAY RUN A SET FOR YOUR OWN FILES. COMMENTS: // f FOR FUTURE REFERENCE ONLY - NO CHANGES REQUIRED: (r 44 L- .s a,��c �E 1tiU `� + � !i J,2r �W✓P. �/vI �'./J 41., S � p5"✓i: . �.4 � �� .0 7 C1;'vr nu -v� CJU7yI MINOR REVISION(S) -Y!'2 PRIOR TO CONSTRUCTION - NO PLAN CHANGES REQUIRED: SORi zcn-A ! S/ Zr 2} y MAJOR PLAN ERROR(S) TO BE REVISED PRIOR TO APPROVAL: /31u77 //�'YtJZJY1 i �/4ir1.� ? MEMO.DOT/A1H �`/�.A.- et- �k� 40J CITY OF RENTON PLANNINGBUILDING/PUBLIC WORKS MEMORANDUM DATE: February 8, 1996 TO: STORM FROM: Ameta H. X6198 8 SUBJECT: VILLAGE ON UNION R2217 C950031 WO#87683 Although I normally hand off the storm drainage info at project close-out I really have no need for it and per your request I am attaching it to this memo. I am attaching all storm drainage reports that I have on this project to this memo. MEMO.DOT/ CRY OF REMON RE C E I V ED JUL 2 2 1994 BUILDING DIVISION THE VILLAGE ON UNION CONCEPTUAL STORM ANALYSIS Prepared by: y Urban Design, Inc. AN 611 Market Street,#3 Kirkland,WA 98033 NAit— (206) 822-4886 EXPIRES July, 1994 OVERVIEW The site is approximately 16.1 acres of mostly undeveloped land. There are single family residential buildings on the site with associated driveway and lawn area. There is also an electric transmission tower and some related clearing for access. The site slopes to the south and the southwest. There are small areas of contributory area from north, but most of the offsite area is intercepted by roads. No drainage structures were found on the site and drainage sheet flows onto the adjacent parcels. The site will be developed with approximately 93 residential homes. The site has been divided into two drainage basins, each with its own retention/detention system. The eastern portion of the site (Basin 1) will drain to an underground percolation system. The western portion (Basin 2) will drain to a combination percolation/detention tank. The outflow will be connected to a 24" pipe south of the site located in Queen Avenue NE. Both areas will drain to a grass lined swale prior to entering the percolation trenches. RETENTIONMETENTION CALCULATIONS The required storage volumes were calculated using the Waterworks computer program. The Santa Unit Hydrograph method was selected for the calculations. Basin 1 uses an underground percolation system sized for a 100 year storm. No outlet is proposed other than emergency overflow. Basin 2 uses a combination of orifice release and percolation trench. A single orifice is proposed which outlets at below the 2, 10, 100 year rates for the corresponding storage volumes. Basin 1 Runoff Calculations Area - 7.2 Developed 50% Impervious - 3.6 Acre 50% Pervious - 3.6 Acre CN = 86 - yard areas good condition P1oo = 3.9 See computer output - Q = 5.17 cfs Basin 2 Runoff Calculations Area - 6.5 acre PZ = 2.0 P,o = 2.9 P,w = 3.9 Existing Conditions: 0.23 Acres Impervious CN = 98 2.50 Acres grass/previously cleared CN = 86 3.77 Acres CN = 76 2.50 x 86 + 3.77 x 76 = 79.99 6.5 See computer print out. Developed Conditions: Area 6.5 acres Impervious = 3.2 acres CN = 98 Pervious = 3.3 acres CN = 86 See computer print out. 7/21/94 Urban Design Inc page 1 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: B1 NAME : BASIN 1 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 7 .20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 3 . 60 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 14 . 11 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 3 . 60 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 100 . 00 ns: 0 . 1500 p2yr: 2 .50 s : 0 . 1000 TcReach - Channel L: 90 . 00 kc:30 . 00 s :0 . 0100 TcReach - Channel L: 555 . 00 kc:42 . 00 s :0 . 0050 TcReach - Channel L: 640 . 00 kc:42 . 00 s :0 . 0500 TcReach - Channel L: 150 . 00 kc: 10 . 00 s :0 . 0050 PEAK RATE: 5 . 17 cfs VOL: 1 . 84 Ac-ft TIME : 480 min BASIN ID: B1D2 NAME: BASIN 1 DEV 2 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 7.20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 3 . 60 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 14 . 11 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 3 . 60 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 100 . 00 ns : 0 . 1500 p2yr: 2 . 50 s : 0 . 1000 TcReach - Channel L: 90 . 00 kc :30 . 00 s: 0 . 0100 TcReach - Channel L: 555 . 00 kc :42 . 00 s: 0 . 0050 TcReach - Channel L: 640 . 00 kc :42 . 00 s: 0 . 0500 TcReach - Channel L: 150 . 00 kc : 10 . 00 s: 0 . 0050 PEAK RATE : 2 .15 cfs VOL: 0 . 79 Ac-ft TIME: 480 min BASIN ID: B2 NAME : BASIN 2 DEV 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 3 . 30 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 42 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 3 . 20 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 90 . 00 ns : 0 . 4000 p2yr: 2 . 50 s : 0 . 0050 TcReach - Shallow L: 220 . 00 ks :27 . 00 s : 0 . 0100 TcReach - Channel L: 540 . 00 kc :42 . 00 s : 0 . 0460 TcReach - Channel L: 60 . 00 kc : 17. 00 s : 0 . 0050 PEAK RATE : 3 . 18 cfs VOL: 1 . 65 Ac-ft TIME: 480 min 7/21/94 Urban Design Inc page 2 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- ---------------------------------------------- BASIN SUMMARY BASIN ID: B210 NAME: BASIN 2 EX 10 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 6 . 27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 . 34 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 0 .23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks :5 . 00 s: 0. 0375 PEAK RATE: 1 . 04 cfs VOL: 0 . 67 Ac-ft TIME : 490 min BASIN ID: B2100 NAME: BASIN2 EX 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . .. 6 .50 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 6 .27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 . 34 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks : 5 . 00 s : 0 . 0375 PEAK RATE: 1 . 90 cfs VOL: 1 . 09 Ac-ft TIME: 490 min BASIN ID: B2D10 NAME: BASIN 2 10 YEAR DEV SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USERI PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 3 . 30 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 42 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 3 . 20 Acres CN. . . . : 98 . 00 PEAK RATE: 2 . 16 cfs VOL: 1 . 15 Ac-ft TIME: 480 min 7/21/94 Urban Design Inc page 3 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ----------------------------------------------------- BASIN SUMMARY BASIN ID: B21)2 NAME: BASIN 2 DEV 2 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : USERI PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 3 . 30 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 42 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 3 .20 Acres CN. . . . : 98 . 00 PEAK RATE: 1 . 29 cfs VOL: 0 .71 Ac-ft TIME : 480 min BASIN ID: B2E2 NAME: BASIN 2 EX 2 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 6 . 27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 . 34 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 .1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks :5 . 00 s : 0 . 0375 PEAK RATE: 0 . 39 cfs VOL: 0 .33 Ac-ft TIME: 490 min 7/21/94 Urban Design Inc page 4 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------------------------------------------------ - HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf-AcFt Acres --------------------------------------------- 1 5 . 173 480 79993 cf 7. 20 2 0 . 387 490 14191 cf 6 . 50 3 1 . 891 490 47478 cf 6 . 50 4 1 .294 480 30781 cf 6 . 50 5 3 . 175 480 71996 cf 6 . 50 6 1 . 058 530 30779 cf 6 . 50 7 1 .458 550 49890 cf 6 . 50 8 1 . 796 560 71994 cf 6 . 50 9 1 . 032 490 28845 cf 6 . 50 10 2 . 163 480 49892 cf 6 . 50 11 2 .450 520 79126 cf 7. 20 12 1 . 065 520 30781 cf 6 . 50 13 1 . 845 490 57947 cf 6 . 50 14 2 .278 520 71996 cf 6 . 50 15 1 . 927 480 30781 cf 6 . 50 20 6 . 331 470 77571 cf 7 . 20 7/21/94 Urban Design Inc page 5 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------------------ --------------------------------------------------------------- STAGE STORAGE TABLE UNDERGROUND PIPE ID No. PIPE Description: PERCOLATION PIPE Diameter: 4 . 00 ft . Length: 575 . 00 ft . Slope . . . : 0 . 0000 ft/ft STAGE <----STORAGE----> STAGE o---STORAGE----> STAGE a----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Pt- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 363.00 0.0000 0.0000 364.10 1615 0.0371 365.20 4072 0.0935 366.30 6376 0.1464 363.10 48.122 0.0011 364.20 1823 0.0419 365.30 4300 0.0987 366.40 6546 0.1503 363.20 135.07 0.0031 364.30 2036 0.0467 365.40 4527 0.1039 366.50 6704 0.1539 363.30 246.22 0.0057 364.40 2254 0.0517 365.50 4751 0.1091 366.60 6850 0.1572 363.40 376.06 0.0086 364.50 2475 0.0568 365.60 4972 0.1141 366.70 6979 0.1602 363.50 521.33 0.0120 364.60 2699 0.0620 365.70 5189 0.1191 366.80 7091 0.1628 363.60 679.63 0.0156 364.70 2926 0.0672 365.80 5403 0.1240 366.90 7178 0.1648 363.70 849.25 0.0195 364.80 3154 0.0724 365.90 5611 0.1268 367.00 7226 0.1659 363.80 1029 0.0236 364.90 3384 0.0777 366.00 5813 0.1335 363.90 1217 0.0279 365.00 3613 0.0829 366.10 6009 0.1379 364.00 1413 0.0324 365.10 3842 0.0882 366.20 6197 0.1423 7/21/94 Urban Design Inc page 6 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- STAGE STORAGE TABLE CUSTOM STORAGE ID No. UT Description: PERCOLATION TRENCH STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- 360.00 866.30 0.0199 366.00 11262 0.2585 372.00 21657 0.4972 378.00 32053 0.7358 360.50 1733 0.0398 366.50 12128 0.2784 372.50 22524 0.5171 378.50 32919 0.7557 361.00 2599 0.0597 367.00 12994 0.2983 373.00 23390 0.5370 379.00 33786 0.7756 361.50 3465 0.0795 367.50 13861 0.3182 373.50 24256 0.5568 379.50 34652 0.7955 362.00 4331 0.0994 368.00 14727 0.3381 374.00 25123 0.5767 380.00 35518 0.8154 362.50 5198 0.1193 368.50 15593 0.3580 374.50 25989 0.5966 380.50 36385 0.8353 363.00 6064 0.1392 369.00 16460 0.3779 375.OD 26655 0.6165 381.00 37251 o.B552 363.50 6930 0.1591 369.50 17326 0.3977 375.50 27722 0.6364 381.50 38117 0.8750 364.00 7797 0.1790 370.00 18192 0.4176 376.00 28588 0.6563 382.00 389B3 0.8949 364.50 8663 0.1989 370.50 19059 0.4375 376.50 29454 0.6762 382.50 39850 0.9148 365.00 9529 0.2188 371.00 19925 0.4574 377.0D 30320 0.6961 383.00 40716 0.9347 365.50 10396 0.2386 371.50 20791 0.4773 377.50 31187 0.7159 383.50 415B2 0.9546 7/21/94 Urban Design Inc page 7 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS -------------------------------------------- STAGE DISCHARGE TABLE DISCHARGE LIST ID No. PT Description: PERCOLATION STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE o-DISCHARGE---> STAGE e--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs 360.00 2.0800 361.50 2.2600 363.00 2.4000 364.00 2.5200 360.50 2.1400 362.00 2.3200 363.50 2.4600 361.00 2.2000 362.50 2.3800 364.00 2.5200 7/21/94 Urban Design Inc page 8 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS -------------- --------------------------------------------------------------------- STAGE DISCHARGE TABLE ➢ISCHARGE LIST ID No. TREN Description: PERCOLATION TRENCH STAGE <--DISCHARGE---> STAGE a--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfS-- ------- 362.00 0.6300 363.50 1.0100 365.00 1.5900 366.50 1.8500 362.50 0.8300 364.00 1.3500 365.50 1.6300 363.00 0.8300 364.50 1.4500 366.00 1.7400 7/21/94 Urban Design Inc page 9 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------------------------------------------------------------ LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAR-> STORAGE <--------DESCRIPTION---------> (cfs) (cfe) --id- --id- <-STAGE> id VOL (ef) AREA 2 2YR ................... 0.39 1.29 PIPE TREN 363.57 6 632.93 AREA 2 10 YR ....... .......... 1.03 2.16 PIPE TREN 364.55 7 2577.20 AREA 2 100 YR ...... ......... . 1.89 3.18 PIPE TREN 366.25 8 6293.34 AREA 1 .. ........... .......... 0.00 5.17 UT PT 363.42 11 6786.77 BIOFILTRATION DESIGN A grass lined swale is proposed for both storm basins. The swales are designed for the developed 2 year flows. Basin 1 - Flow = 2.15 cfs Swale bottom required = 6.18' (per Flowmaster computer printout) Basin 2 - Flow = 1.29 cfs Swale bottom required - 3.28' (per Flowmaster computer printout) Top width required is 7.30' Swale length provided is 62', therefore 200/62 = 3.2 3.2 x 7.3 = 23.4' Required top width is 23.4' } Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name : VILLAGE ON UNION Comment : GRASS LINED SWALE Solve For Bottom Width Given Input Data: Left Side Slope . . 3 . 00 : 1 (H:V) Right Side Slope. 3 . 00 : 1 (H:V) Manning' s n. . . . . . 0 .350 Channel Slope. . . . 0 . 0200 ft/ft Depth. . . . . . . . . . . . 0 . 67 ft Discharge. . . . . . . . 1 .29 cfs Computed Results : Bottom Width. . . . 3 .28 ft Velocity. . . . . . . . . 0 .36 fps Flow Area. . . . . . . . 3 .55 sf Flow Top Width. . . 7 .30 ft Wetted Perimeter. 7 .52 ft Critical Depth. . . 0 .16 ft Critical Slope . . . 3 .4792 ft/ft Froude Number. . . . 0 . 09 (flow is Subcritical) Open Channel Flow Module, Version 3 . 12 (c) 1990 Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name : VILLAGE ON UNION Comment : GRASS LINED SWALE Solve For Bottom Width Given Input Data: Left Side Slope. . 3 . 00 :1 (H:V) Right Side Slope. 3 . 00 :1 (H:V) Manning' s n. . . . . . 0 . 350 Channel Slope . . . . 0 .0200 ft/ft Depth. . . . . . . . . . . . 0 .67 ft Discharge . . . . . . . . 2 .15 cfs Computed Results : Bottom Width. . . . 6 .18 ft Velocity. . . . . . . . . 0 . 39 fps Flow Area. . . . . . . . 5.49 sf Flow Top Width. . . 10.20 ft Wetted Perimeter. 10 .42 ft Critical Depth. . . 0 .15 ft Critical Slope. . . 3 .4569 ft/ft Froude Number. . . . 0 . 09 (flow is Subcritical) Open Channel Flow Module, Version 3 . 12 (c) 1990 Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 DOWNSTREAM ANALYSIS The western detention/retention system will outlet to an existing 24" pipe in Queen Avenue NE. The pipe is 276 linear feet at 0.942% flowing to the south. The flow then continues south in a 27" pipe at 0.397/a slope for 340 linear feet and enters a catch basin in 4th Street. Flow then turns west in a 12" concrete pipe approximately 80 feet long to a catch basin that outlets via a 27" concrete pipe. This pipe is 48 linear feet at 1.542% slope. Flow again heads west in a 27" concrete pipe at 1.305% for 456 linear feet to a catch basin that outlets to another 27" concrete pipe at 1.10% slope for 409 linear feet. Concern has been expressed by City staff in regards to the downstream drainage system. Therefore percolation was used on site for a portion of the drainage control system, thus reducing both the volume and the peak runoff rate that will be released. ■i �� �11111111i �11111111n111111� �®�■■�■n n® 1111i 111 MQ11111eR1111161r� n� 111111 folio im 11111111/�� � .1111©1111\ per,��/� �F, �. •. �►�,A//�,�� IIIIIIIn11► ���1�� Cn � � 4T : s � 11111111111► . �., ��� H,� �.111111111111111111111 11111n �� an 111111111111111111111 IIIIIn . 1111� ® ��: �IIIIIIII Ilnn�� II . RI URBAN DESIGN, INC. Environmental Planning Civil Engineering Landscape Design & Project Management Services January 30, 1995 MEMORANDUM TO: Bob Arthur, City of Renton FROM: Donna Emery, Urban Design, Inc. RE: Village On Union The landscape plan is being submitted without an irrigation plan. We have recently been informed that irrigation is required for this project. A detailed irrigation plan at 20' scale will be included when these plans are re-submitted following review and plan check comments. 5�W19 --2 7- z?-7 _Z 2117 ) Corporate Office.• 611 Market Street, Suite 3 *Kirkland, WA 98033 • Telephone: (206) 822-4886 Fax: (206) 822-7870 Hawaii Office: 311 South Lehua Street •Kahului, Maui, HI 96732 • Telephone: (808) 871-5701 • : a t • ■ DESCRIPTION Mgt! MA . ii .C�.�_ .. !►-�._ � sue!!!!i :__ .. r . � �. !ar�_- ,��.�.,w / _orw IO 82 76 1 69� ( S / 60 81 � \ � / 77 / 68 " 1 80 67 / / / 40 Ul 45 79 i 65 se / 111 t 66 : / _ J Ml/ O ( - I (D / Go -- 1 78� 15" EASEMENT Q �44/ 41 GRASS IINED tLE/DETENTION YSTEM a I 43 A 4 63 t 62 61 i t I t 1 LF PERF. ORIFICE All 3 3 C2 ) W T W "T ST W W W /LLAG per/ �/tlioN I �� �/JF/L7P f77/c'�✓ % S'% l ,� �✓� I � T� � l � S Cr�C� : / = '�lC 'FEU u rr� � A G R A AGRA Earth& Earth & Environmental 11335 NE 1 21nd Way Suite 100 Kirkland,Washington U.S.A. 98034.6918 Tel (206)820.4669 Fax(206)821-3914 22 November 1994 1 1-09 994-00 Northwest Commercial 740 Koll Center 500 108th Avenue Northeast Bellevue, Washington 98004 Attention: Mr. Jack Willing Subject: Winter Infiltration Test Results The Village on Union Renton, Washington Dear Mr. Willing: This letter report presents the results of our winter subsurface infiltration rate testing for the proposed development on the south side of Northeast 6th Street between Queen and Union Avenues Northeast in Renton, Washington. The subject property and the approximate locations of the explorations accomplished for this evaluation are shown on the Site and Exploration Plan, Figure 1. The scope of our services consisted of completing six on-site infiltration rate measurements, and preparation of this report. This letter report has been prepared in accordance with generally accepted geotechnical engineering practices for the exclusive use of Northwest Commercial. and their agents, for specific application to this project. The scope of work for this evaluation was performed in accordance with our proposal number 11 p-7941, dated 12 October 1994. Site and Project Description The site is located on the south side of Northeast 6th Street between Queen and Union Avenues Northeast in Renton, Washington, as indicated on the site plan. The site occupies a south - facing slope several acres in size, and is currently occupied by one residence. The project would consist of constructing a new multifamily residential development with associated appurtenances. F Engineering&Environmental Services Northwest Commercial 22 November 1994 11-09994-00 Page 2 Infiltration Rate Testing Six subsurface maximum infiltration rate tests were performed on 21 November 1994 in general accordance with the guidelines published in Section 4.5.2 of the King County Surface Water Design Manual, with tests located in planned infiltration areas, as indicated on the attached site plan. The test depths were approximately 10 feet below ground surface. The tests were run as a "falling head" tests, with head changing from approximately 6 to 5.5 feet during each timing cycle. L ble 1 , Infiltration Test Results Test Number Maximum Infiltration Rate, minutes per inch IT-1 5.6 IT-2 3.8 IT-3 4.5 IT-4 1 .1 IT-5 1.3 IT-6 1 .0 The United States Department of Agriculture Soil Conservation Service classification for the site is Arents Alderwood material (AmC). Logs of the infiltration test holes are appended to this report. � AG RA Earth & Environmental Northwest Commercial 22 November 1994 11-09994-00 Page 3 Infiltration Rate Testing Methods Infiltration rate tests presented in this report were completed in general accordance with those presented in the King County Surface Water Design Manual, Section 4.5.2, Subsurface Maximum Infiltration Rate Test. This method involves excavating a pit to the test elevation, and driving a 6 - inch diameter pipe six inches into the test soil. The pipe is then filled with enough water to produce a one foot high column of water in the pipe. A minimum one foot column of water is maintained in the pipe during a four hour saturation period. Following the saturation period, the pipe is filled until it contains a four foot tall water column. For this site, due to the depths of the test holes, a water column 6 feet in height was used. The times required for the water level in the pipe to drop each inch, for the first six inches, is recorded. This test is completed three times, and all of the one - inch drop times are averaged to obtain Im, the maximum infiltration rate. We appreciate the opportunity to be of service to you on this project. If you have any questions or comments regarding this report, or require further information after reviewing this report, please do not hesitate to call us. Respectfully submitted, AGRA Earth a vironmental, Inc. e W. Guenzler Project Geologist 1S EAS IAp �oF two ? z ohn E. Zipp TVTE Associate 2dALS EXPIRES 1 /24/9S Enclosure: Figure 1 - Site and Exploration Plan Test Pit Logs TP-1 through TP-6 BWG/KDM/clt * AGRA Earth & Environmental TEST PIT LOGS Depth (feet) Soil Classification 11-09994-00 Test Pit TP-1 Approximate ground surface elevation: 370 feet 0.0 - 0.5 Topsoil, sod, fine roots 0.5 - 3.5 Medium dense to dense, damp, mottled gray, silty, gravelly SAND. 3.5 - 9.8 Dense to very dense, moist, gray, gravelly, fine to coarse SAND, trace to some silt Test pit terminated at approximately 9.8 feet No caving No seepage Test Pit TP-2 Approximate ground surface elevation: 370 feet 0.0 - 0.5 Topsoil, sod, and fine roots 0.5 - 3.8 Medium dense, moist, mottled gray, silty, gravelly SAND 3.8 - 10.0 Dense to very dense, moist, gray, gravelly, fine to coarse SAND, trace to some silt Test pit terminated at approximately 10.0 feet No caving No seepage Test Pit TP-0 Approximate ground surface elevation: 370 feet 0.0 - 0.5 Topsoil, sod, and fine roots 0.5 - 4.5 Medium dense, moist, mottled gray, silty, gravelly, fine to coarse SAND 4.5 - 10.1 Dense to very dense, damp, gray, gravelly, fine to coarse SAND, trace to some silt Test pit terminated at approximately 10.1 feet No caving No seepage 11-09994-00 Test Pic Logs, Page 2 Depth (feet) Soil Classification Test Pit TP-4 Approximate ground surface elevation: 370 feet 0.0 - 1.0 Topsoil, duff, and fine roots 1.0 - 5.0 Medium dense to dense, moist,tan to gray, fine to medium SAND,trace to some gravel, trace silt 5.0 - 9.9 Grades to medium dense to dense Test pit terminated at approximately 9.9 feet No caving No seepage Test Pit TP-5 Approximate ground surface elevation: 370 feet 0.0 - 1.0 Topsoil, duff, and fine roots 1.0 - 4.3 Medium dense to dense, moist, tan to gray, fine to medium SAND,trace to some gravel, trace silt 4.3 - 10.0 Grades to medium dense to dense Test pit terminated at approximately 10.0 feet No caving No seepage Test Pit TPE Approximate ground surface elevation: 370 feet 0.0 - 1.0 Topsoil, duff, and fine roots 1.0 - 4.5 Medium dense to dense, moist,tan to gray,fine to medium SAND,trace to some gravel, trace silt 4.5 - 10.2 Grades to medium dense to dense Test pit terminated at approximately 10.2 feet No caving No seepage Date excavated: 21 November 1994 Logged by: BWG DOWNSTREAM ANALYSIS The western detention/retention system will outlet to an existing 24" pipe in Queen Avenue NE. The pipe is 276 linear feet at 0.942% flowing to the south. The flow then continues south in a 27" pipe at 0.397% slope for 340 linear feet and enters a catch basin in 4th Street. Flow then turns west in a 12" concrete pipe approximately 80 feet long to a catch basin that outlets via a 27" concrete pipe. This pipe is 48 linear feet at 1.542% slope. Flow again heads west in a 27" concrete pipe at 1.305% for 456 linear feet to a catch basin that outlets to another 27" concrete pipe at 1.10% slope for 409 linear feet. Concern has been expressed by City staff in regards to the downstream drainage system. Therefore percolation was used on site for a portion of the drainage control system, thus reducing both the volume and the peak runoff rate that will be released. IV. Detention Water Quality Analysis and Design Existing Hydrology Since infiltration is used exclusively for Basin I no existing hydrology is necessary. Basin 2 Area = 7.07 acres Pervious area = 6.84 acres CN = 80 - average value includes wooded area, grasses, second growth & landscaping Impervious = 0.23 Ac. includes house, outbuildings, driveway, etc. T� L, = 300' S = 0.0167 sheet flow Lz = 480' S = 0.0375 shallow flow Basin 2 - Modified Area = 4.55 Ac - note: 2.52 acres were diverted to Basin I. Impervious = 2.55 acres CN = 98 Pervious = 2.00 acres CN = 86 Hydrologic Analysis The Waterworks computer program was utilized to size both of the retention/detention systems. The rational method was used to size the conveyance system with the Flowmaster computer program used to calculate pipe capacities and velocities. Developed Site Hydrology Basin I Area = 8.05 acres - note: this includes some contributory offsite area and some area of Basin 2 that has been redirected to the infiltration system. Time of concentration was taken from conveyance calculations = 16.7 min. Impervious taken as approximately 58% - Over 7 lots per acre. Impervious = 4.66 acres CN=98 Pervious = 3.39 acres Use CN = 85 - some lawns, some landscaped, treed areas from offsite. 1/27/95 Urban Design Inc page 1 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- ------------------- ------------------------------------ BASIN RESULT SUMMARY BASIN -----VOLUME---- -RATE- ----TIME----- Hydrograph Area ID ---cf-- Ac-ft --cfs- -min- hours Methodology Acres B1 91150 2.09 5.63 480 8.00 SBUH Method 8.05 B1D2 39799 0.91 2.40 480 8.00 SBUH Method 8.05 B2 51768 1.19 2.89 480 8.00 SBUH Method 4.55 B210 31415 0.72 1.12 490 8.17 SBUH Method 7.07 B2100 51709 1.19 2.06 490 8.17 SBUH Method 7.07 B21>10 36153 0.83 2.00 480 8.00 SBUH Method 4.55 B2D2 22588 0.52 1.23 480 S.DD SBUH Method 4.55 B2E2 15448 0.35 0.42 490 8.17 SBUH Method 7.07 1/27/95 Urban Design Inc page 1 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: Bl NAME : BASIN 1 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 8 . 05 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 3 . 39 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 TIME OF CONC. . . . . : 16 . 70 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 4 . 66 Acres CN. . . . : 98 . 00 PEAK RATE: 5 . 63 cfs VOL: 2 . 09 Ac-ft TIME: 480 min BASIN ID: B1D2 NAME: BASIN 1 DEV 2 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 8 . 05 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USERI PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 3 . 39 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 TIME OF CONC. . . . . : 16 . 70 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 4 . 66 Acres CN. . . . : 98 . 00 PEAK RATE : 2 .40 cfs VOL: 0 . 91 Ac-ft TIME : 480 min BASIN ID: B2 NAME : BASIN 2 DEV 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 55 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 2 . 00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 23 . 30 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 2 . 55 Acres CN. . . . : 98 . 00 PEAK RATE: 2 . 89 cfs VOL: 1 . 19 Ac-ft TIME: 480 min 1/27/95 Urban Design Inc page 2 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------------------ -------------------------------- BASIN SUMMARY BASIN ID: B210 NAME : EX 10 YR BASIN 2 SBUH METHODOLOGY TOTAL AREA. . . . . . . : 7 . 07 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 6 . 84 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 . 34 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks : 5 . 00 s : 0 . 0375 PEAK RATE: 1 . 12 cfs VOL: 0 . 72 Ac-ft TIME: 490 min BASIN ID: 132100 NAME: BASIN2 EX 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 7 . 07 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 6 . 84 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 . 34 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks : 5 . 00 s : 0 . 0375 PEAK RATE : 2 . 06 cfs VOL: 1 . 19 Ac-ft TIME: 490 min BASIN ID: B2D10 NAME : BASIN 2 10 YEAR DEV SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 55 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 2 . 00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 23 . 30 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 2 . 55 Acres CN. . . . : 98 . 00 PEAK RATE : 2 . 00 cfs VOL : 0 . 83 Ac-ft TIME : 480 min 1/27/95 Urban Design Inc page 3 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- --------------------------------------------------------- BASIN SUMMARY BASIN ID: B2D2 NAME : BASIN 2 DEV 2 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 55 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 2 . 00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 23 . 30 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 2 . 55 Acres CN. . . . : 98 . 00 PEAK RATE : 1 . 23 cfs VOL: 0 . 52 Ac-ft TIME: 480 min BASIN ID: B2E2 NAME : BASIN 2 EX 2 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 7 . 07 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 6 . 84 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 . 34 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr : 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks : 5 . 00 s : 0 . 0375 PEAK RATE: 0 .42 cfs VOL: 0 . 35 Ac-ft TIME : 490 min 1/27/95 Urban Design Inc page 2 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- ------------------------------------------------------------ HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf-AcFt Acres --------------------------------------------- 1 5 . 631 460 91150 cf 8 . 05 2 0 . 422 490 15448 cf 7 . 07 3 2 . 062 490 51709 cf 7 . 07 4 1 . 228 480 22588 cf 4 . 55 5 2 . 894 480 51758 cf 4 . 55 6 0 . 639 540 22071 cf 4 . 55 7 1 . 572 510 35636 cf 4 . 55 8 2 . 162 510 51241 cf 4 . 55 9 1 . 125 490 31415 cf 7 . 07 10 2 . 002 480 36153 cf 4 . 55 11 3 . 214 520 90284 cf 8 . 05 12 1 . 065 520 30781 cf 6 . 50 13 1 . 845 490 57947 cf 6 . 50 14 2 . 278 520 71996 cf 6 . 50 15 1 . 927 480 30781 cf 6 . 50 20 6 . 331 470 77571 cf 7 . 20 1/27/95 Urban Design Inc page 3 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS -------------------------------------------------------------------- STAGE STORAGE TABLE CUSTOM STORAGE ID No. TREN2 Description: RETENTION / DETENTION BASIN 2 STAGE <----STORAGE----- STAGE -----STORAGE----> STAGE <----STORAGE----> STAGE -----STORAGE----> (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 359.50 517.00 0.0119 360.70 1758 0.0404 361.90 2999 0.0688 363.10 4239 0.0973 359.60 620.40 0.0142 360.80 1861 0.0427 362.00 3102 0.0712 363.20 4343 0.0997 359.70 723.80 0.0166 360.90 1965 0.0451 362.10 3205 0.0736 363.30 4446 0.1021 359.80 827.20 0.0190 361.00 2068 0.0475 362.20 3309 0.0760 363.40 4350 0.1044 339.90 930.60 0.0214 361.10 2171 0.0498 362.30 3412 0.0783 363.50 4653 0.1068 360.00 1034 0.0237 361.20 2275 0.0522 362.40 3516 0.0807 363.60 4756 0.1092 360.10 1137 0.0261 361.30 2378 0.0546 362.50 3619 0.0831 363.70 4860 0.1116 360.20 1241 0.0285 361.40 2482 0.0570 362.60 3722 0.0855 363.80 4963 0.1139 360.30 1344 0.0309 361.50 2585 0.0593 362.70 3826 0.0878 363.90 5067 0.1163 360.40 1448 0.0332 361.60 2688 0.0617 362.80 3929 0.0902 360.50 1551 0.0356 361.70 2792 0.0641 362.90 4033 0.0926 360.60 1654 0.0360 361.80 2895 0.0665 363.00 4136 0.0949 1/27/95 Urban Design Inc page 4 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- ---------------------------------STAGE STORAGE STORAGE TABLE CUSTOM STORAGE ID No. UT Description: PERCOLATION TRENCH STAGE o----STORAGE----> STAGE c----STORAGE----> STAGE <----STORAGE----> STAGE a----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 360.40 866.30 0.0199 361.50 2772 0.0636 363.00 5371 0.1233 364.60 7970 0.1830 360.50 1040 0.0239 362.00 3638 0.0835 363.50 6237 0.1432 361.00 1906 0.043E 362.50 4505 0.1034 364.00 7104 0.1631 1/27/95 Urban Design Inc page 5 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------ ----------- -------------------- STAGE DISCHARGE TABLE COMBINATION DISCHARGE ID No. B2OUT Description: COMBINATION Structure : ORI Structure : Structure : TREN Structure : Structure : STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 359.50 0.3120 360.70 0.5319 361.90 1.3001 363.10 2.0281 359.60 0.3134 360.80 0.5468 362.00 1.3832 363.20 2.0745 359.70 0.3148 360.90 0.5609 362.10 1.4591 363.30 2.1196 359.80 0.3162 361.00 0.5742 362.20 1.5294 363.40 2.1636 359.90 0.3176 361.10 0.5882 362.30 1.5954 363.50 2.2065 360.00 0.3190 361.20 0.6015 362.40 1.6578 363.60 2.2475 360.10 0.3976 361.30 0.6145 362.50 1.7171 363.70 2.2876 360.20 0.4310 361.40 0.6270 362.60 1.7738 363.B0 2.3269 360.30 0.4570 361.50 0.6392 362.70 1.8283 363.90 2.3654 360.40 0.4791 361.60 0.9593 362.80 1.8808 364.00 2.4031 360.50 0.4987 361.70 1.0981 362.90 1.9314 360.60 0.5160 361.80 1.2070 363.00 1.9805 1/27/95 Urban Design Inc page 6 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS -------------------- ----------------------------------- STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No . ORI Description: BASIN 2 ORIFICE STRUCTURE Outlet Elev: 360 . 00 Elev: 358 . 00 ft Orifice Diameter: 3 . 0000 in. Elev: 361 . 50 ft Orifice 2 Diameter: 6 . 0000 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---CfS-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 360.00 0.0000 361.80 0.8628 363.60 1.8791 365.40 2.4968 360.10 0.0772 361.90 0.9545 363.70 1.9188 365.50 2.5266 360.20 0.1092 362.00 1.0362 363.80 1.9577 365.60 2.5561 360.30 0.1338 362.10 1.1107 363.90 1.9958 365.70 2.5852 360.40 0.1545 362.20 1.1796 364.00 2.0331 365.80 2.6140 360.50 0.1727 36230 1.2442 364.10 2.0698 365.90 2.6425 360.60 0.1892 362.40 1.3052 364.20 2.1058 366.00 2.6706 360.70 0.2043 362.50 1.3631 364.30 2.1412 366.10 2.6985 360.80 0.2184 362.60 1.4184 364.40 2.1760 366.20 2.7261 360.90 0.2317 362.70 1.4715 364.50 2.2102 366.30 2.7534 361.00 0.2442 362.80 1.5226 364.60 2.2439 366.40 2.7804 361.10 0.2562 362.90 1.5718 364.70 2.2771 366.50 2.8072 361.20 0.2675 363.00 1.6195 364.80 2.3098 366.60 2.8337 361.30 0.2785 363.10 1.6657 364.90 2.3420 366.70 2.8599 361.40 0.2890 363.20 1.7107 365.00 2.3739 366.80 2.8859 361.50 0.2992 363.30 1.7544 365.10 2.4052 366.90 2.9117 361.60 0.6179 363.40 1.7970 365.20 2.4361 367.00 2.9373 361.70 0.7553 363.50 1.8385 365.30 2.4667 1/27/95 Urban Design Inc page 7 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------------------------------------------------------------ STAGE DISCHARGE TABLE DISCHARGE LIST I➢ No. PT Description: BASIN 1 PERCOLATION STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---Cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 360.40 2.4000 361.60 2.7120 362.80 3.0240 364.00 3.4360 360.50 2.4260 361.70 2.7380 362.90 3.0500 364.10 3.4620 360.60 2.4520 361.80 2.7640 363.00 3.0960 364.20 3.4880 360.70 2.4780 361.90 2.7900 363.10 3.1420 364.30 3.5140 360.80 2.5040 362.00 2.8160 363.20 3.1880 364.40 3.5400 360.90 2.5300 362.10 2.8420 363.30 3.2340 364.50 3.5660 361.00 2.5560 362.20 2.8680 363.40 3.2800 364.60 3.5920 361.10 2.5820 362.30 2.8940 363.50 3.3060 364.70 3.6180 361.20 2.6080 362.40 2.9200 363.60 3.3320 364.80 3.6440 361.30 2.6340 362.50 2.9460 363.70 3.3580 364.90 3.6700 361.40 2.6600 362.60 2.9720 363.80 3.3840 361.50 2.6860 362.70 2.9980 363.90 3.4100 1/27/95 Urban Design Inc page 8 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ===------ STAGE DISCHARGE TABLE DISCHARGE LIST ID No. TREN Description: BASIN 2 PERCOLATION STAGE c--DISCHARGE---> STAGE c--DISCHARGE---> STAGE a-DISCHARGE---> STAGE c--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 359.50 0.3120 360.70 0.3276 361.90 0.3456 363.10 0.3624 359.60 0.3134 360.80 0.32B4 362.00 0.3470 363.20 0.363E 359.70 0.314E 360.90 0.3292 362.10 0.3484 363.30 0.3652 359.80 0.3162 361.00 0.3300 362.20 0.3498 363.40 0.3666 359.90 0.3176 361.10 0.3320 362.30 0.3512 363.50 0.36B0 360.00 0.3190 361.20 0.3340 362.40 0.3526 363.60 0.3684 360.10 0.3204 361.30 0.3360 362.50 0.3540 363.70 0.3698 360.20 0.3218 361.40 0.33B0 362.60 0.3554 363.80 0.3692 360.30 0.3232 361.50 0.3400 362.70 0.356E 363.90 0.3696 360.40 0.3246 361.60 0.3414 362.80 0.35B2 364.00 0.3700 360.50 0.3260 361.70 0.342E 362.90 0.3596 360.60 0.3268 361.90 0.3442 363.00 0.3610 1/27/95 Urban Design Inc page 9 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS -------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAX-> STORAGE ---------DESCRIPTION---------� (cfs) (cfs) --id- --id- -STAGE> id VOL (cf) AREA 2 2YR ...... . . . .......... 0.42 1.23 TREN2 B20UT 361.50 6 2584.31 AREA 2 10 YR ... . . ............ 1.12 2.00 TREN2 1320UT 362.26 7 3375.37 AREA 2 100 YR .. . . ............ 2.06 2.89 TREN2 B20UT 363.40 8 4545.52 AREA 1 ........ . . ............. 0.00 5.63 UT PT 363.26 11 5814.50 Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name: VILLAGE �yt�� Comment: GRASS LINED SWALE f Solve For Bottom Width Given Input Data: Left Side Slope.. 3.00:1 (H:V) Right Side Slope. 3.00:1 (H:V) Manning's n...... 0.350 Channel Slope.... 0.0200 ft/ft Depth... . . ....... 0.67 ft Discharge. ....... 2.40 cfs Computed Results: Bottom Width.... 7.02 ft Velocity. . . ...... 0.40 fps Flow Area. . ...... 6.05 sf Flow Top Width... 11.04 ft Wetted Perimeter. 11.25 ft Critical Depth... 0.15 ft Critical Slope... 3.4535 ft/ft Froude Number.... 0.09 (flow is Subcritical) Open Channel Flow Module, Version 3.12 (c) 1990 Haestad Methods, Inc. * 37 Brookside Rd • Waterbury, Ct 06708 Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Wcrksheet Name : v Comment : Grass lined Swale Solve For Bottom Width Given Input Data: Left Side Slope . . 3 . 00 : 1 (H:V) Right Side Slope . 3 . 00 :1 (H:V) Manning' s n. . . . . . 0 . 350 Channel Slope . . . . 0 . 0200 ft/ft Depth. . . . . . . . . . . . 0 . 67 ft Discharge . . . . . . . . 1 .23 cfs Computed Results : Bottom Width. . . . 3 . 06 ft Velocity. . . . . . . . . 0 . 36 fps Flow Area. . . . . . . . 3 .41 sf Flow Top Width. . . 7 . 10 ft Wetted Perimeter. 7 . 31 ft Critical Depth. . . 0 . 16 ft Critical Slope . . . 3 .4822 ft/ft Froude Number. . . . 0 . 09 (flow is Subcritical) Open Channel Flow Module, Version 3 . 12 (c) 1990 Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 V. Conveyance System Analysis and Design ADDI,- URBAN DESIGN, INC. SHEET NO. of 611 Market Street, Suite 3 a KIRKLAND, WA 98033 CALCULATED BY = DATE (206) 822.4886 FAX (206) 822.7870 CHECKED BY DATE SCALE lr� 17oQ 2u ; � = y7 v /` ✓� v: . =`J '-�"/7.` i {')/.-. r'' %i O, :J '��E✓ _ '_. GU �l/Jl/%'��T1", �: _ Si.L�t�=-''-;. Ire .a✓ �5 .Sh7u�Y; In -.��`l.rpr . CONVEYANCE SYSTEM ANALYSIS AND SIZING TABLE USING THE RATIONAL METHOD z Location Area C C•A Sum T i I t Pi T Slo OF V V L T &I � Sub Basin Number c a a n yp' .) (pipe (pipe (at L4 From—FT-0-1 (ac) C•A (min.) (c.f.s. (in.) n (tt.tt.) full full O ) (ft.) 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'gMAPlEW00D �I_ E cim •k y" K ° sr rx 22 AV 21 ,O % ='� , fNr P RIVER 7 c SI + F ¢ aQQ PARK t o'"xi Tn AA! € W.O. 1109994 THE VILLAGE ON UNION AG RA DESIGN BWG _ RENTON, WASHINGTON i Earth & Environmental DRAWN DMW LOCATION MAP 11335 NE 122nd Way, Suite 100 w DATE NOV 1994 Kirktand,Washington, U.S.A. 98034-6918 SCALE N.T.S FIGURE 1 a I I I I ul ; z , w Lu Qz z z I z Io w 2 i � � t I I I � 1 I Qi IT-3 IT-2 • IT-1 PROPO: 0 100 200 LE IT-6 SCALE IN FEET 0 INFILTRATIC APPROXIMA THE VILLAGE ON UNION g RENTON, WASHINGTON SITE & EXPLORATION PLAN A a DRAWING BASED ON PLAN BY URBAN DESIGN, IN( Fl RE 2 _ VII. Basin and Community Plan Area VIII. Other Permits IX. Erosion/Sedimentation Control Design X. Bond Quantities Worksheet, Retention / Detention Facility Summary Sheet and Declaration Covenant JD6J il�aq� on (�v�ioVl - URBAN DESIGN, INC. SHEET NO. OF 611 Market Street, Suite 3 KIRKLAND, WA 98033 CALCULATED BY DATE 11120 �f 5 (206) 822.4886 FAX (206) 822.7870 CHECKED BY DATE SCALE �OYId (�LIGZN ` � > l�j `1J 10� �QIGI-lIa+Gd XI. Maintenance and Operations Manual No.12. Access Roads/Easements Figure I. b. Scale V = 2400' JOB `'/ I a c U URBAN DESIGN, INC. SHEET NO. OF 611 Market Street, Suite 3 C KIRKLAND, WA 98033 CALCULATED BY DATE 2a 95 (206) 822.4886 FAX (206) 822-7870 CHECKED BY DATE SCALE ��oS�aN Co�IJTIZoL 7, = IZ`�xLsxcUXP2 ,:,oiL - ALderwooa 3, 15 'V = I , O (/Jc, cover j 3>(I.t)� ( 1 L G-Efl es V= / gN,/Q 0 j� r �b = 57 �t Lt_ -7g �P-Mrs Tv ME�r vXc_��j �s� �i�1�<✓ ��i✓, III. Off-Site Analysis (Level 1) � � ���1�����1 ����IIIII�11111�� �®■■■�i■� !loo11 meIN! �Ie�i11111�31� milli �■¢��ii1 IiI©������i1�� Nil 33,E7-21 /11111/1 � ■�� � � ¢���s Hp - 111111111� �11111111111 �1111� � �� �� -_ 1111©1111111111111111 11111� �111� �IS II � J - I1 �- ■ -of a.b THE VILLAGE ON UNION CONCEPTUAL STORM ANALYSIS RE ° E ON v Ep 7 6 1994 BU(LDiNG Dfy�i� °.a Prepared by: Urban Design, Inc. ,,�� 611 Market Street,#3 Kirkland,WA 98033 `S�OtVALFt" (206) 822-4886 ExaiRES Zy/�j July, 1994 OVERVIEW The site is approximately 16.1 acres of mostly undeveloped land. There are single family residential buildings on the site with associated driveway and lawn area. There is also an electric transmission tower and some related clearing for access. The site slopes to the south and the southwest. There are small areas of contributory area from north, but most of the offsite area is intercepted by roads. No drainage structures were found on the site and drainage sheet flows onto the adjacent parcels. The site will be developed with approximately 93 residential homes. The site has been divided into two drainage basins, each with its own retention/detention system. The eastern portion of the site (Basin 1) will drain to an underground percolation system. The western portion (Basin 2) will drain to a combination percolation/detention tank. The outflow will be connected to a 24" pipe south of the site located in Queen Avenue NE. Both areas will drain to a grass lined swale prior to entering the percolation trenches. RETENTION/DETENTION CALCULATIONS The required storage volumes were calculated using the Waterworks computer program. The Santa Unit Hydrograph method was selected for the calculations. Basin 1 uses an underground percolation system sized for a 100 year storm. No outlet is proposed other than emergency overflow. Basin 2 uses a combination of orifice release and percolation trench. A single orifice is proposed which outlets at below the 2, 10, 100 year rates for the corresponding storage volumes. Basin 1 Runoff Calculations Area - 7.2 Developed 50% Impervious - 3.6 Acre 50% Pervious - 3.6 Acre CN = 86 - yard areas good condition P,00 = 3.9 See computer output - Q = 5.17 cfs Basin 2 Runoff Calculations Area - 6.5 acre PZ = 2.0 P10 = 2.9 P100 = 3.9 Existing Conditions: 0.23 Acres Impervious CN = 98 2.50 Acres grass/previously cleared CN = 86 3.77 Acres CN = 76 2.50 x 86 + 3.77 x 76 = 79.99 6.5 See computer print out. Developed Conditions: Area 6.5 acres Impervious = 3.2 acres CN = 98 Pervious = 3.3 acres CN = 86 See computer print out. 7/21/94 Urban Design Inc page 1 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- ----- ----------------------- BASIN SUMMARY BASIN ID: B1 NAME: BASIN 1 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 7 .20 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 3 . 60 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 14 . 11 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA.. : 3 . 60 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 100 . 00 ns : 0 . 1500 p2yr: 2 . 50 s: 0 . 1000 TcReach - Channel L: 90 . 00 kc :30 . 00 s: 0. 0100 TcReach - Channel L: 555 . 00 kc :42 . 00 s: 0 . 0050 TcReach - Channel L: 640 . 00 kc :42 . 00 s :0. 0500 TcReach - Channel L: 150 . 00 kc : 10 . 00 s:0. 0050 PEAK RATE : 5 . 17 cfs VOL: 1 . 84 Ac-ft TIME: 480 min BASIN ID: B1D2 NAME: BASIN 1 DEV 2 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 7 . 20 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 3 . 60 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 14 . 11 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 3 . 60 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 100 . 00 ns : 0 . 1500 p2yr: 2 . 50 s : 0 . 1000 TcReach - Channel L: 90 . 00 kc: 30 . 00 s :0 . 0100 TcReach - Channel L: 555 . 00 kc:42 . 00 s :0 . 0050 TcReach - Channel L: 640 . 00 kc :42 . 00 s :0 . 0500 TcReach - Channel L: 150 . 00 kc : 10 . 00 s :0 . 0050 PEAK RATE: 2 . 15 cfs VOL: 0 . 79 Ac-ft TIME: 480 min BASIN ID: B2 NAME: BASIN 2 DEV 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 .50 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 3 . 30 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . . 42 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 3 . 20 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 90 . 00 ns: 0 .4000 p2yr: 2 . 50 s : 0 . 0050 TcReach - Shallow L: 220 . 00 ks :27 . 00 s :0 . 0100 TcReach - Channel L: 540 . 00 kc :42 . 00 s :0 . 0460 TcReach - Channel L: 60 . 00 kc :17 . 00 s :0 .0050 PEAK RATE : 3 . 18 cfs VOL: 1 . 65 Ac-ft TIME : 480 min 7/21/94 Urban Design Inc page 2 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- BASIN SUMMARY BASIN ID : B210 NAME: BASIN 2 EX 10 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 6 . 27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 .34 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks :5 . 00 s : 0 . 0375 PEAK RATE: 1 . 04 cfs VOL: 0 . 67 Ac-ft TIME: 490 min BASIN ID: B2100 NAME: BASIN2 EX 100 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 .50 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 6 . 27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 . 34 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks : 5 . 00 s : 0 . 0375 PEAK RATE : 1 . 90 cfs VOL: 1 . 09 Ac-ft TIME: 490 min BASIN ID: B2D10 NAME: BASIN 2 10 YEAR DEV SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 3 . 30 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 42 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 3 . 20 Acres CN. . . . : 98 . 00 PEAK RATE: 2 . 16 cfs VOL: 1 . 15 Ac-ft TIME: 480 min 7/21/94 Urban Design Inc page 3 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ----------------------------------------------------------------- BASIN SUMMARY BASIN ID: B2D2 NAME : BASIN 2 DEV 2 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 3 .30 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 42 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 3 . 20 Acres CN. . . . : 98 . 00 PEAK RATE: 1 .29 cfs VOL: 0 . 71 Ac-ft TIME : 480 min BASIN ID: B2E2 NAME: BASIN 2 EX 2 YR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 6 . 50 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 6 . 27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 80 . 00 TIME OF CONC. . . . . : 40 .34 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 23 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns :0 . 1500 p2yr: 2 . 00 s : 0 . 0167 TcReach - Shallow L: 480 . 00 ks :5 . 00 s : 0 . 0375 PEAK RATE : 0 . 39 cfs VOL: 0 . 33 Ac-ft TIME : 490 min 7/21/94 Urban Design Inc page 4 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------- ---------------------------------------------------------------- HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf-AcFt Acres --------------------------------------------- ----------------------- 1 5 . 173 480 79993 cf 7. 20 2 0 . 387 490 14191 cf 6 . 50 3 1 . 891 490 47478 cf 6 . 50 4 1.294 480 30781 cf 6. 50 5 3 . 175 480 71996 cf 6 . 50 6 1 . 058 530 30779 cf 6 . 50 7 1 .458 550 49890 cf 6 . 50 8 1 . 796 560 71994 cf 6 . 50 9 1. 032 490 28645 cf 6 . 50 10 2 . 163 480 49892 cf 6 .50 11 2 . 450 520 79126 cf 7.20 12 1 . 065 520 30781 cf 6 . 50 13 1 . 845 490 57947 cf 6 . 50 14 2 . 278 520 71996 cf 6 . 50 15 1 . 927 480 30781 cf 6 . 50 20 6 . 331 470 77571 cf 7. 20 7/21/94 Urban Design Inc page 5 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS -------------- --------------------------------------------------------------------- STAGE STORAGE TABLE UNDERGROUND PIPE ID No. PIPE Description: PERCOLATION PIPE Diameter: 4 . 00 ft. Length: 575 . 00 ft . Slope. . . : 0 . 0000 ft/ft STAGE a---STORAGE----> STAGE c----STORAGE----> STAGE a---STORAGE----- STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- 363.00 0.0000 0.0000 364.10 1615 0.0371 365.20 4072 0.0935 366.30 6376 0.1464 363.10 48.122 0.0011 364.20 1823 0.0419 365.30 4300 0.0987 366.40 6546 0.1503 363.20 135.07 0.0031 364.30 2036 0.0467 365.40 4527 0.1039 366.50 6704 0.1539 363.30 246.22 0.0057 36440 2254 0.0517 365.50 4751 0.1091 366.60 6850 0.1572 363.40 376.06 0.0086 364.50 2475 0.0568 365.60 4972 0.1141 366.70 6979 0.1602 363.50 521.33 0.0120 364.60 2699 0.0620 365.70 5189 0.1191 366.80 7091 0.1628 363.60 679.63 0.0156 364.70 2926 0.0672 365.80 5403 0.1240 366.90 7178 0.1648 363.70 849.25 0.0195 364.S0 3154 0.0724 365.90 5611 0.1288 367.00 7226 0.1659 363.80 1029 0.0236 364.90 3384 0.0777 366.00 5813 0.1335 363.90 1217 0.0279 365.00 3613 0.0829 366.10 6009 0.1379 364.00 1413 0.0324 365.10 3842 0.0882 366.20 6197 0.1423 7/21/94 Urban Design Inc page 6 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- ------------------------------------------------------- ------ STAGE STORAGE TABLE CUSTOM STORAGE ID No. UT Description: PERCOLATION TRENCH STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 360.00 866.30 0.0199 366.00 11262 0.2585 372.00 2165] 0.49]2 378.00 32053 0.7358 360.50 1733 0.0398 366.50 12126 0.2784 372.50 22524 0.5171 378.50 32919 0.7557 361.00 2599 0.0597 367.00 12994 0.2983 373.00 23390 0.5370 379.00 33786 0.7756 361.50 3465 ❑.0795 367.50 13861 0.3182 373.50 24256 0.5568 379.50 34652 0.7955 362.00 4331 0.0994 368.00 14727 0.3381 374.00 25123 0.5767 380.00 35518 0.8154 362.50 5198 0.1293 368.50 15593 0.3580 374.50 25989 0.5966 380.50 36385 0.8353 363.00 6064 0.1392 369.00 16460 0.3779 375.00 26855 0.6165 381.00 37251 0.8552 363.50 6930 0.1591 369.50 17326 0.3977 375.50 27722 0.6364 381.50 38117 0.8750 364.00 7797 0.1790 370.00 16192 0.4176 376.00 28588 0.6563 382.00 38983 0.8949 364.50 8663 0.1989 370.50 19059 0.4375 376.50 29454 0.6762 382.50 39850 0.9148 365.00 9529 0.2188 371.00 19925 0.4574 377.00 30320 0.6961 3B3.00 40716 0.9347 365.50 10396 0.2386 371.50 20791 0.4773 377.50 31187 0.7159 383.50 41582 0.9546 7/21/94 Urban Design Inc page 7 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS --------------------------------------------------------------------- STAGE DISCHARGE TABLE DISCHARGE LIST ID No. PT Description: PERCOLATION STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> Ift) ---CfS-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 360.00 2.0800 361.50 2.2600 363.00 2.4000 364.00 2.5200 360.50 2.1400 362.00 2.3200 363.50 2.4600 361.00. 2.2000 362.50 2.3800 364.00. 2.5200 7/21/94 Urban Design Inc page S THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS ------------- ----------------------------------------------------------------- STAGE DISCHARGE TABLE DISCHARGE LIST ID No. TREN Description: PERCOLATION TRENCH STAGE <--DISCHARGE---> STAGE c--DISCHARGE---> STAGE <--DISCHARGE---> STAGE c--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfa-- ------- (ft) ---cfa-- ------- (ft) ---cfS-- ------- ______==;: __===----a__._---__«""""----------- ------------====---------- s 362.00 0.8300 363.50 1.0100 365.00 1.5400 366.50 1.8500 362.50 0.8300 364.00 1.3500 365.50 1.6300 363.00 0.8300 364.50 1.4500 366.00 1.7400 7/21/94 Urban Design Inc page 9 THE VILLAGE ON UNION RETENTION/DETENTION CALCULATIONS -------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> STORAGE <--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf) AREA 2 2YR ............... .... 0.39 1.29 PIPE TREN 363.57 6 632.93 AREA 2 10 YR ............... .. 1.03 2.16 PIPE TREN 364.55 7 2577.20 AREA 2 100 YR ................ 1.89 3.18 PIPE TREK 366.25 8 6293.34 AREA 1 0.00 5.17 UT PT 363.42 11 6786.77 BIOFILTRATION DESIGN A grass lined swale is proposed for both storm basins. The swales are designed for the developed 2 year flows. Basin 1 - Flow = 2.15 cfs Swale bottom required = 6.18' (per Flowmaster computer printout) Basin 2 - Flow = 1.29 cfs Swale bottom required - 3.28' (per Flowmaster computer printout) Top width required is 7.30' Swale length provided is 62', therefore 200/62 = 3.2 3.2 x 7.3 = 23.4' Required top width is 23.4' Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name: VILLAGE ON UNION Comment : GRASS LINED SWALE Solve For Bottom Width Given Input Data: Left Side Slope. . 3 . 00 :1 (H:V) Right Side Slope. . 3 . 00 :1 (H:V) Manning' s n. . . . . . 0 .350 Channel Slope. . . . 0 . 0200 ft/ft Depth. . . . . . . . . . . . 0 . 67 ft Discharge. . . . . . . . 1.29 cfs Computed Results : Bottom Width. . . . 3 .28 ft Velocity. . . . . . . . . 0 .36 fps Flow Area . . . . . . . . 3 . 55 sf Flow Top Width. . . 7.30 ft Wetted Perimeter. 7 . 52 ft Critical Depth. . . 0 . 16 ft Critical Slope. . . 3 .4792 ft/ft Froude Number. . . . 0 . 09 (flow is Subcritical) Open Channel Flow Module, Version 3 . 12 (c) 1990 Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name : VILLAGE ON UNION Comment : GRASS LINED SWALE Solve For Bottom Width Given Input Data: Left Side Slope . . 3 . 00 :1 (H:V) Right Side Slope . 3 . 00 : 1 (H:V) Manning' s n. . . . . . 0 . 350 Channel Slope . . . . 0 . 0200 ft/ft Depth. . . . . . . . . . . . 0 . 67 ft Discharge. . . . . . . . 2 . 15 cfs Computed Results : Bottom Width. . . . 6 . 18 ft Velocity. . . . . . . . . 0 . 39 fps Flow Area. . . . . . . . 5 .49 sf Flow Top Width. . . 10 . 20 ft Wetted Perimeter. 10 .42 ft Critical Depth. . . 0 . 15 ft Critical Slope . . . 3 .4569 ft/ft Froude Number. . . . 0 . 09 (flow is Subcritical) Open Channel Flow Module, Version 3 . 12 (c) 1990 Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 DOWNSTREAM ANALYSIS The western detention/retention system will outlet to an existing 24" pipe in Queen Avenue NE. The pipe is 276 linear feet at 0.942% flowing to the south. The flow then continues south in a 27" pipe at 0.397% slope for 340 linear feet and enters a catch basin in 4th Street. Flow then turns west in a 12" concrete pipe approximately 80 feet long to a catch basin that outlets via a 27" concrete pipe. This pipe is 48 linear feet at 1.542% slope. Flow again heads west in a 27" concrete pipe at 1.305% for 456 linear feet to a catch basin that outlets to another 27" concrete pipe at 1.10% slope for 409 linear feet. Concern has been expressed by City staff in regards to the downstream drainage system. Therefore percolation was used on site for a portion of the drainage control system, thus reducing both the volume and the peak runoff rate that will be released. ®� ���I�����i �11111111�111111 ® ■man loll��l��/� C 1!�Illeil11111�Ir� NONNI NONE al11111 IN IIIii111111► �, ��� H� � 1111111111� �i1111111111 �1111� � C� A '_ IIIi©IIIII� �IIIIIi11111 11111� �- �111� ®� ��� 111111�111 HE II �� EWMTRATION TESTING RESULTS PROJECT: The Village on Lake Union Union Avenue NE and NE 6th Street Renton, Washington SUBSURFACE CONDITIONS AND INFILTRATION TESTING: The project site is mapped as Alderwood gravelly sandy loam according to the Soil Survey for the King County Area (Figure 2). During our site reconnaissance, we observed exposed sands and gravels throughout the site. We hand-excavated three test pits for the purpose of infiltration testing. The approximate locations of these test pits are shown on Figure 3. Test pits TP-1 and TP-2 were excavated to a depth of approximately three feet from the surface. The soils disclosed by test pits TP-1 and TP-2 consisted of medium dense to dense, moist, brown, silty,gravelly SAND. Test pit TP-3 was approximately four feet deep and consisted of medium dense to dense, moist, medium to coarse, gravelly SAND, with some silt. We performed infiltration testing in each test pit in accordance with the King County Surface Water Design Manual Sec. 4.5.2. The infiltration rates were as follows: TP-1 8 min/in TP-2 1 min/in TP-3 0.5 min/in $EE Ii1u MH I ,E � zvo n 4A _. �> _ N •f 6Tx � i '� 3 r.w t / _'t r' 4� ouwu � Ss s� ,.,m v .�„ � Il1 r (, Z � �i ' ix , Wp r Caw :.,+� ,.1. Lx o Z Qi 1 •�. N(M st nxl ,:. 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BI,D N • M t.B c •u •ii• AgD -70 m B AM 2 210 76 0 AgC Tu P. z AgC Arj E M AmC O V IBM 203 29 A01 A,C 451 N. r A,C 94.011 TECHNICAL INFORMATION REPORT FOR VILLAGE ON UNION Prepared by: Urban Design, Inc. 611 Market Street, Suite 3 Kirkland, WA 98033 (206) 8224886 January 31, 1995 TABLE OF CONTENTS I. Project Overview II. Preliminary Conditions Summary Recommendations (with statements) III. Off-Site Analysis IV. Retention/Detention Analysis and Design V. .,.. Conveyance System Analysis and Design VI. Special Reports VII. Basin and Community Plan Areas VIII. Other Permits IX. Erosion / Sedimentation Control Design X. Bond Quantities Worksheet, Retention / Detention Facility Summary Sheet and Declaration Covenant XI. Maintenance and Operations Manual No.12. Access Roads/Easements I. Project Overview Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PAFrrli* PROJECT OWNER ANMT��!�-� PROJECT -, = � . . . . � . Projectowner Al lid eDmy &,i 10 -r1�—_. Project Name 7rhe V� 14ye on Union Address 714 �nkkC&VI e.1"' �°l1PVLlC'i Location Phone —(a4(o • In 31 1 Township 9 Project Engineer f v Range 2,3 Company 1A ( GLP) DgttZI n Section 5E Address Phone Project Size AC /2 �� ' F�Z7_ ' `� 8�0 Upstream Drainage Basin Size AC LT • livill 911 •I Subdivision Q DOF/G HPA Q Shoreline Management Q Short Subdivision Q COE 404 Q Rockery Q Grading Q DOE Dam Safety Q Structural Vaults Q Commercial Q FEMAFloodplain Q Other Q Other Q COE Wetlands Q HPA • `,Y4 4 77 Community Drainage Basin Q River Q Floodplain Q Stream Q Wetlands Q Critical Stream Reach Q Seeps/Springs Q Depressions/Swales Q High Groundwater Table Q Lake Q Groundwater Recharge Q Steep Slopes Q Other Q Lakeside/Erosion Hazard g. G Soil T e Slo s Erosion Po ntial Erosive Velocities y,� Q Additional Sheets Attatched 1/90 4w si 'Ir vxS+' Arinlss .y NE A71 4TH § ST " • � z ` ? � � � x� I � LRE � Tf LZXTN ,� Y Q - ._ 41PBxr _. ♦ rir y$� �V _.L 9 r,w P SE Y )215T• St_1 i1 �r I e N AIBPpHi NY i sr'" NE �-DES•- si L ,`13ir0 •I i n Ls I x0 Si i� � S ilLLl Sr Sn s� rx0 K \ �, IAI 2N i t TBBx srul� x Y�o.r � i 1i5 �,: � •Lr b u j n) Ial :L • �')Hrxi I" 1 1c[xT6r 3 h w y w & "Ra i 7c c u r "^4 z Z '3 5T „ " eira 3 sonar In s x Irvin '{��� 3 .� •� w _ ` S 2N ' .11 sF P sL 1%TN 5t ,.•P�i a '�w3 °y 8 '' $ 3R0 S <' '< // � � I � '+e "-,+Lx� �Y . � p � y I r n w • " R i}. Al41 4,N k!F N PAW:Y %I r n UNS sT "`i�i�y, W i s eM r xs'wr IN r "� Xs q! RO sf srx h [ExrtN 141St . /s � 1 EA + imp i 2 yb " s jrx s _/ Y i r , l/ ` I4 xu sI I lu� 9 f 5 X y ` �` H ^V- y siw� NvtE 1 % a ° g � yA V �x s it s MQPLE 4 S AFII}a rIEN1 `RWOODi s �� A � g T,X a IFaW� �, I'. �•. X,r �'��Tss a h I ♦ r /i \��_� '< ervEB y b 6TN 19IX T NNr N n tf% nx I w a. lx l,n n,q W' f.♦ N•b . IpG as axy rrMAf c 3 P 4fi, µ• o a'b0 .\w u^�'n'ss b Is'rOe '� Ys'Jry Ml'SE ! K t T T 3 �6E ` W ES rySauA ,.� FAIRWOODi,< xl;a•H e y N e H I y t Yl�a x _4 5 y _ F y 3 ,}T S41YIL. bM y ' -- 4 r � P$y d s sr ♦ (- SX 2z ,r R, , sf t m TT 5E I6ATNi �$T E t ♦• EadH = '. 5 5 �� 1 SDM• Irl YI In 'f E 1651X Sr � y $E 64TN ). � ! sY'[p �3 aW ii 3t ^al y j ic r • Wsa W " si m u€ys w 1 v,n [[? P e l law su�zesr �Ys[Lgsw rL 1�6 ¢5 . � " ,i4f4s 6 all 54 ST SI 5X 38m r N _ E o 16Bm~M K Si 6 u T B r"4 +r r j u sr lu u € < •, - '^ Ll � ISxra ' lr ^r a E ` L 11r8 5r , _ II [ ^ _ , • 3 r $ P '� a i w e SE 17 m SI ; 4 L •!f 5� .Y-,x 66� ,eixmx L� ]4m SI 9 _ .. ..I .: 6 [ F .. n u r , YI IPARX u yLIB p { S wsr _ E' , a % „w ♦ it l>l1l N.. 1 N M3% t Ijjry ^i � � A r... Y�^H� r•,.n 1 �� 'b i 7 I s van$r � Y• � �'_ n r - • 3 a w STH 5T / 5 r • . ?4 sF ussw u° % SE y E1R�TSSK't v5on } alf 8 -V 5r I y L5L M SI/" Fa VALLff ♦ CV__ W I PM bM 49 /irolGLL S tO L SEE + 1 6T ST l)B OVERVIEW The site is approximately 12 acres of mostly undeveloped land. There are single family residential buildings on the site with associated driveway and lawn area. There is also an electric transmission tower and some related clearing for access. The site slopes to the south and the southwest. There are small areas of contributory area from north, but most of the offsite area is intercepted by roads. No drainage structures were found on the site and drainage sheet flows onto the adjacent parcels. The site will be developed with approximately 92 residential homes. The site has been divided into two drainage basins, each with its own retention/detention system. The eastern portion of the site (Basin 1) will drain to an underground percolation system. The western portion (Basin 2)will drain to a combination percolation/detention tank. The outflow will be connected to a 24" pipe south of the site located in Queen Avenue NE. Both areas will drain to a grass lined swale prior to entering the percolation trenches. II. Preliminary Condition Summary