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thatcherdrain.pdf-DmAir6r____� ■ CAV Lovell-Sauerland and Associates, Inc. Phone: 425-775-1591 E N o N E R e r 9 U R V E v U R a Z 19400 33rd Avenue West, Suite 200 Fax: 425-672-7998 _- Lynnwood, Washington 98036 LSAEngineering.rnm LSA No. 4918 October 5, 2006 Attn: City of Edmonds, Department of Public Works Edward Sibrel- Engineering Reviewer From: Robert L. Long, PE Project: Thatcher Residence -8505 200th St SW D Mr. and Mrs. Thatcher are proposing to build a new residence at 8505 2001h St SW in the City of Edmonds. The new residence will include the following new impervious surfaces: House and Garage .................... 3,950 sf Driveway, walk and patio ............ 1,450 sf Total = 5,400 sf Due to the fact the proposed impervious surface is greater than 5,000 sf, located in a stream basin (Northstream) and the site is less than 1.0 acres (0.300 ac.) the proposed development will need to collect, detain and match the release rates for the 2 -year, 10 - year, and 100 -year design storms (matching the release rates for the pre -developed conditions- forested). The applicant has decided to install a cast -in-place detention vault in place of the standard pipe/tank system. Attached are calculations and schematic design of the vault. The proposed vault will provide 581 cf 2' x 8'x 3.3`) of active (live) storage and an additional 264 cf (22'x 8'x 1.5'} o �erment (dead) storage. The permanent storage will provide a water quality function for tm. See attached exhibits. If you have any questions or need additional in%afmation Lovell-Sauerland & Assoc. LSA No. 4918 EXPIRES 8#1?f0 Robert L. Long, PE ■ �Ao I i: iii` ' z a Thatcher Residence October 5, 2006 569'4'20' 8'133' 9'1 ctas LINE WATER LINE / n CB#2 TOP=96.0± IE=93.24 96 r----------- I DETENTION VAUL P 4'2'(L) x 8'(W) x 5.0'(x) i�-----_`---J 'I 28'-8" PVC ® 1.0% TIE INTO EX. STROM SYSTEM ON SOUTH SIDE OF 200TH ST SW EX CB TOP=95.5± EE=92.87 N89'4'20"E 1'1.60' — CB#1 TOP=98.5± IE=93.72 APPRaOXEMATE EDGE OF EXISTIW. GARAGE 1 TO BE DEMOLISHED 200th 5tr ret S.W. impervaus Coverage RESIDENCE/GARAGE 3,950 sr DRIVEWAY AND WALKS 1.450 or TOTAL 5,400 5r 111=201 i I -----fib----J : � d l I i�A.IN FLOOR:iEL"E*/ATi0z:1.:96.50 -. RIDGE ELEV.'?T.ION !2290 .�. lACTVA;A .4CTU'AL RIS rtr-VATIGN 1Z21B�5 E7QTT01"I fJF FgOTlNCs 95&9 r I / I I a. f r` I _ fiARACsE r AREA DRAIN TOP=98.0 IE=95.56 I 1 a ra d� CONCRETE. Z N DRIVEwaY 1 r IV r----------- I DETENTION VAUL P 4'2'(L) x 8'(W) x 5.0'(x) i�-----_`---J 'I 28'-8" PVC ® 1.0% TIE INTO EX. STROM SYSTEM ON SOUTH SIDE OF 200TH ST SW EX CB TOP=95.5± EE=92.87 N89'4'20"E 1'1.60' — CB#1 TOP=98.5± IE=93.72 APPRaOXEMATE EDGE OF EXISTIW. GARAGE 1 TO BE DEMOLISHED 200th 5tr ret S.W. impervaus Coverage RESIDENCE/GARAGE 3,950 sr DRIVEWAY AND WALKS 1.450 or TOTAL 5,400 5r 111=201 VAULT ACCESS - S 36" DIA. TOP ACCESS--- W/ SOLID LOCKING LID 22.0' �r//71 PLAN VIEW C3 C3 co k ACCESS LOCKING LID ELEV. 99.50± OFFSET WHERE OPENING IS DIRECTLY OVER LADDER AND RESTRICTOR IS VISIBLE AT ONE EDGE OF GRATE ELEV. 97.5071 •'� �:•. P'ti ' `:r' RISER ELEV. 97.30 - 1 97.3 0 ---------------------- 00 YR = ---------- PIPE SUPPORT / 6" ELBOW r10 YR. = 95.79 �LEV. 95.33 ------------------ -----� __—W__- -� 2 YR. --_=_25 3j_ d ;.1J 3/4" ORIFICE m --�-FLOW ! ! I \v ELEV. 94.00 _17 DEAD STORAGE ELEV, 94.00 I ! I 4r L3" ELEV. = 95.00 P T' v a DETENTION VAULT a a v 22'(L) x 8'(W) x 5.0'(1)) TO CMP CROSS. HOLE LIVE VOLUME - 581 CF 44a DEAD VOLUME =264 CF TO BE SHARP -EGGED, --- CONTROL STRUCTURE SHOP DRILLED. r I I l 1 ii CONCRETE VAULT ELEV. 92.50 TO BE DESIGNED BY OTHERS) , DETENTION VAULT DETAIL PLAN VIEW C3 C3 co k ACCESS LOCKING LID ELEV. 99.50± OFFSET WHERE OPENING IS DIRECTLY OVER LADDER AND RESTRICTOR IS VISIBLE AT ONE EDGE OF GRATE ELEV. 97.5071 •'� �:•. P'ti ' `:r' RISER ELEV. 97.30 - 1 97.3 0 ---------------------- 00 YR = ---------- PIPE SUPPORT / 6" ELBOW r10 YR. = 95.79 �LEV. 95.33 ------------------ -----� __—W__- -� 2 YR. --_=_25 3j_ d ;.1J 3/4" ORIFICE m --�-FLOW ELEV. 94.00 _17 DEAD STORAGE ELEV, 94.00 MIN CLEARANCE 4r L3" ELEV. 93.50 CUT HOLE 5/8" DIA. IN 12 GA. 12" PLATE AND WELD TO CMP CROSS. HOLE TO BE SHARP -EGGED, SHOP DRILLED. ELEV. 92.50 , DETENTION VAULT DETAIL NO SCALE 1014106 2:31:63 pm Shareware Release page 1 THATCHER RESIDENCE LSA #4918 LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO--DIS- -PEAK- OUTFLOW STORAGE < DESCRIPTION-> (cfs) (cfs)--id--id- <STAGE> id (cis) VOL (cf) 2 YEAR ....................... 0.01 0.05 V2 C2 95.31 1 0.01 231.10 cf 10 YEAR ...................... 0.02 0.08 V2 C2 95.79 2 0.02 315.52 cf 100 YEAR ..................... 0.06 0.14 V2 C2 97.30 3 0.05 581.06 cf BASIN SUMMARY BASIN ID: E002 NAME: EXISTING 2 YR SBUH METHODOLOGY TOTAL AREA.......: 0.30 Acres BASEFLOWS: 0.00 cls RAINFALL TYPE....: TYPE1A PERV IMP PRECIPITATION....: 1.50 inches AREA..: 0.30 Acres 0.00 Acres TIME INTERVAL....: 10.00 min CN....: 81.00 0.00 TC....: 26.24 min 0.00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 80.00 ns:0.4000 p2yr: 1.50 5:0.0200 PEAK RATE: 0.01 cfs VOL: 0.01 Ac -ft TIME: 540 min BASIN ID: E010 NAME: EXISTfNG 10 YR SBUH METHODOLOGY TOTAL AREA....,..: 0.30 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE....; TYPEIA PERV IMP PRECIPITATION....: 2.00 inches AREA..: 0.30 Acres 0.00 Acres TIME INTERVAL....: 10.00 min CN....: 81.00 0.00 TC....: 26.24 min 0.00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 80.00 ns:0.4000 p2yr: 1.50 s:0.0200 PEAK RATE: 0.02 cls VOL: 0.02 Ac -ft TIME: 490 min BASIN ID: E100 NAME: EXISTING 100 YR SBUH METHODOLOGY TOTAL AREA.......: 0.30 Acres BASEFLOWS: 0.00 cls RAINFALL TYPE....: TYPEIA PERV IMP PRECIPITATION....: 3.00 inches AREA..: 0.30 Acres 0.00 Acres TIME INTERVAL....: 10.00 min CN....: 81.00 0.00 TC....: 26.24 min 0.00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 80.00 ns:0.4000 p2yr: 1.50 s:0.0200 PEAK RATE: 0.06 cfs VOL: 0.03 Ac -ft TIME: 490 min STAGE STORAGE TABLE RECTANGULAR VAULT ID No. V2 Descrip6om DETENTION VAULT Length: 22.00 ft. Width: 8.00 ft. voids: 1.000 BASIN ID: D002 NAME: DEVELOPED 2 YR SBUH METHODOLOGY TOTAL AREA.......: 0.30 Anes BASEFLOWS: 0.00cfs RAINFALL TYPE....: TYPEIA PERV IMP PRECIPITATION....: 1.50 inches AREA..: 0.18 Acres 0.12 Acres TIME INTERVAL....: 10.00 min GN....: 86.00 98.00 TC....: 10.00 min 10.00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 80.00 ns:0.4000 p2yr. 1.50 s:0.0200 PEAK RATE: 0.05 cfs VOL: 0.02 Ac -ft TIME: 480 min BASIN ID: D010 NAME: DEVELOPED 10 YR SBUH METHODOLOGY TOTAL AREA.......: 0.30 Acres BASEFLOWS: 0.00 cls RAINFALL TYPE....: TYPEIA PERV IMP PRECIPITATION....: 2.00 inches AREA..: 0.18 Acres 0.12 Acres TIME INTERVAL....; 10.00 min CN....: 86.00 98.00 TO-.: 10.00 min 10.00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 80.00 ns:0.4000 p2yr: 1.50 0,0200 PEAK RATE: 0.08 cfs VOL: 0.03 Ac -ft TIME: 480 min BASIN ID: D100 NAME. DEVELOPED 100 YR SBUH METHODOLOGY TOTAL AREA.......: 0.30 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE....: TYPEIA PERV IMP PRECIPITATION....: 3.00inches AREA..: 0.18Acres 0.12Acres TIME INTERVAL....: 10.00 min CN....: 86.00 98.00 TC....: 10.00 min 10.00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 80.00 ns:0.4000 p2yr. 1.50 s:0.0200 PEAK RATE: 0.14 ors VOL: 0.05 Ac -ft TIME: 480 min STAGE <-STORAGE-> STAGE <--STORAGE-> STAGE -STORAGE ---- > STAGE ­STORAGE- >(ft)---cf-- Ac -Ft- (ft) --cf---Ac-Ft- (ft) -cf---Ac-Ft- (ft) -cf--Ac-Ft- 94.00 0.0000 0.0000 95.10 193.60 0.0044 96.20 387.20 0.0089 97.30 580.80 0.0133 94.10 17.600 0.0004 95.20 211.20 0.0048 96.30 404.80 0.0093 97.40 598.40 0.0137 94.20 35.200 0.0008 95.30 228.80 0.0053 96.40 422.40 0.0097 97.50 616.00 0.0141 94.30 52.800 0.0012 95.40 246.40 0.0057 96.50 440.00 0.0101 97.60 633.60 0.0145 94.40 70.400 0.0016 95.50 264.00 0.0061 96.60 457.60 0.0105 97.70 651.20 0.0149 94.50 88.000 0.0020 95.60 281.60 0.0065 96.70 475.20 0.0109 97.80 668.80 0.0154 94.60 105.60 0.0024 95.70 299.20 0.0069 96.80 492.80 0.0113 97.90 686.40 0.0158 94.70 123.20 0.0028 95.80 316.80 0.0073 96.90 510.40 0.0117 98.00 704.00 0.0162 94.80 140.80 0.0032 95.90 334.40 0.0077 97.00 528.00 0.0121 98.00 704.00 0.0162 94.90 158.40 0.0036 96.00 352.00 0.0081 97.10 545.60 0.0125 95.00 176.00 0.0040 96.10 369.60 0.0085 97.20 563.20 0.0129 Lovell-Sauerland & Assoc. Thatcher Residence LSA No. 4918 October 5, 2006 ■ `>rl• � Z Thatcher Residence- 200th St SW SCS Weighted average curve number calculations SCS Soil= Tokul SCS Hydrologic Soils type:---> C Existing conditions Assumptions: Undisturbed forest land Second growth forest Meadow or pasture Grass, > 75% coverage Grass, > 50% coverage Open water Impervious Future conditions Assumptions: Undisturbed forest land Second growth forest Meadow or pasture Grass, > 75% coverage Grass, > 50% coverage Open water Impervious Lovell-Sauerland & Assoc. LSA No. 4918 LSA No. 4918 Oct. 4, 2006 Impervious: Area, acres: 0.000 Percent impervious area: Weighted CN: CN: Basin Area Development Area (sf) = 13,072 Total (Ac.)= 0.300 CN: 76 7,672 81 13,072 85 86 5,400 100 3,950 92 9,450 98 91.0 Total Weighted CN: 81.0 Pervious: 0.176 Area, acres: 0.300 Percent pervious area: 100.0% Weighted CN: 81.0 Impervious: Area, acres: 0.000 Percent impervious area: Weighted CN: CN: 76 81 85 86 7,672 90 100 98 5,400 Houselgarage Roof 3,950 Driveway, Patio and Walk 9,450 Total Weighted CN: 91.0 Pervious: Area, acres: 0.176 Percent pervious area: 58.7% Weighted CN: 86.0 Impervious: Area, acres: 0.124 Percent impervious area: 41.3% Weighted CN: 98.0 z Thatcher Residence October 5, 2006 STAGE DISCHARGE TABLE COMBINATION DISCHARGE ID No. C2 Description: CONTROL STURCUTRE Structure: 02 Structure: R2 STAGE <-DISCHARGE-> STAGE <-.DISCHARGE-> STAGE -DISCHARGE- STAGE <-DISCHARGE-> (ft) -_cfs- - (ft) _ds-- --- (ft) -cfs- -- (ft)---cfs- -- 94.00 0.0000 95.10 0.0111 96.20 0.0299 97.30 0.0407 94.10 0.0034 95.20 0.0116 96.30 0.0311 97.40 0.5730 94,20 0.0047 95.30 0.0121 96.40 0.0322 97.50 0.7940 94.30 0.0058 95.40 0.0165 96.50 0.0333 97.60 0.9638 94.40 0.0067 95.50 0.0192 96.60 0.0343 97.70 1.1070 94.50 0.0075 95.60 0.0213 96.70 0.0353 97.80 1.2332 94.60 0.0082 95.70 0.0231 96.80 0.0362 97.90 1.3474 94.70 0.0089 95.80 0.0247 96.90 0.0372 98.00 1.4525 94.80 0.0095 95.90 0.0261 97.00 0.0381 94.90 0.0101 96.00 0.0275 97.10 0.0390 95.00 0:0106 96.10 0.0287 97.20 0.0398 MULTIPLE ORIFICE ID No. 02 Description: CONTROL ORIFICE Outlet Elev: 94.00 Elev: 94.00 ft Orifice Diameter: 0.6250 in. Elev: 95.33 ft Orifice 2 Diameter: 0.75001n, STAGE <--DISCHARGE---> STAGE < DISCHARGE-> STAGE <-DISCHARGE--> STAGE <-DISCHARGE-> RISER DISCHARGE ID No. R2 Description: RISER Riser Diameter (in): 8.00 elev: 97.30 ft Weir Coefficient...: 9.739 height: 98.00 ft Of Coefficient...: 3.782 increm: 0.10 ft STAGE -DISCHARGE- STAGE <-DISCHARGE-> STAGE -DISCHARGE- STAGE <-DISCHARGE---> - 94,00 0.0000 95.10 0.0111 96.20 0.0299 97.30 0.0407 94.10 0.0034 95.20 0.0116 96.30 0.0311 97.40 0.0415 94.20 0.0047 95.30 0.0121 96.40 0.0322 97.50 0.0423 94.30 0.0058 95.40 0.0165 96.50 0.0333 97.60 0.0431 94.40 0.0067 95.50 0.0192 96.60 0.0343 97.70 0.0439 94.50 0.0075 95.60 0.0213 96.70 0.0353 97.80 0.0446 94.60 0.0082 95.70 0.0231 96.80 0.0362 97.90 0.0454 94.70 0.0089 95.80 0,0247 96.90 0.0372 98.00 0.0461 94.80 0.0095 95.90 0.0261 97.00 0.0381 94,90 0.0101 96.00 0.0275 97.10 0.0390 95.00 0.0106 96.10 0.0287 97.20 0.0398. RISER DISCHARGE ID No. R2 Description: RISER Riser Diameter (in): 8.00 elev: 97.30 ft Weir Coefficient...: 9.739 height: 98.00 ft Of Coefficient...: 3.782 increm: 0.10 ft STAGE -DISCHARGE- STAGE <-DISCHARGE-> STAGE -DISCHARGE- STAGE <-DISCHARGE---> Lovell-Sauerfand & Assoc. LSA No. 4918 C z Thatcher Residence October 5, 2006 97.30 0.0000 97.50 0.7517 97.80 1.1886 98.00 1.4063 97.30 0.0000 97.60 0.9207 97.90 1.3020 97.40 0.5315 97.70 1.0631 98.00 1.4063 Lovell-Sauerfand & Assoc. LSA No. 4918 C z Thatcher Residence October 5, 2006