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HomeMy WebLinkAboutSWP272867(2) 4205 148th Ave.N.E.Suite 200 CORE Bellevue,Washington 98007 425.885.7877 Fax 425.885.7963 V DESIGN STORM DRAINAGE REPORT FOR. MAPLEWOOD PARCEL RENTON, WASHINGTON Qto PREPARED BY: Gina R. Brooks, P.E. APPROVED BY: David E. Cayton, P.E. GE DATE: February, 2000iotYAL REVISED: June, 2000, August, 2000s6-12— October, 2000 (Section IIIB & C. Only) CORE PROJECT NO.: 94168 l - let -i tr ENGINEERING PLANNING • SURVEYING B. Water Quality Calculations A combination of dead storage in the pond along with a biofiltration swale will be used for mitigation of the stormwater to meet Special Requirement #5 and Core Requirement #3 of the 1990 King County Surface Water Design Manual. DEAD STORAGE According to the 1990 King County Surface Water Design Manual, the required volume for dead storage of the ponds shall be equal to the water quality storm in the developed condition. The water quality storm is defined as a storm having a precipitation equal to 1/3 of the 2-year precipitation. The required surface area for the dead storage of the ponds shall be equal to 1% of the impervious surface area tributary to the pond. The areas considered for treatment are those areas tributary to the detention pond. These areas include the developed site along with any open space and tributary area captured by the storm drainage system conveying drainage to the pond. For each area considered for treatment, 6-month storms were calculated. The areas were summed to arrive at a required volume for water quality. See WaterWorks hydrograph summary printout in Section IIIC. Hydrograph 13 is the sum of the 6-month storm events of the developed site plus the open space plus the tributary areas (1 & 3). See basin summary printouts on the following pages. The dead storage required for the pond is 51,440 CF. Refer to the volume calculations spreadsheet on the following pages. Dead storage will be accomplished from elevation 388 to elevation 392.5. The dead storage provided is 94,639 CF which is more than the required. The required dead storage surface area is equal to 1%*(23.06 + 0.00+ 5.69 + 0.80) AC = 12,872 SF. At elevation 392.5, the surface area is equal to 25,500 SF which exceeds the minimum. 6/12/00 4 : 36 : 15 pm Dodds Engineers, Incorporated page i MAPLEWOOD PARCEL PROJECT NO. 94168 --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: DEV6MO NAME: DEV SITE 6 MONTH STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 48 . 70 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 0 . 67 inches AREA. . : 25 . 64 Acres 23 . 06 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 29 . 53 min 29 . 53 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 30 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 .3300 TcReach - Sheet L: 100 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0050 TcReach - Channel L: 235 . 00 kc :42 . 00 s : 0 . 0420 TcReach - Channel L :2767 . 00 kc :42 . 00 s : 0 . 0340 impTcReach - Sheet L: 30 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 3300 impTcReach - Sheet L: 100 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0050 impTcReach - Channel L: 235 . 00 kc :42 . 00 s : 0 . 0420 impTcReach - Channel L:2767 . 00 kc :42 . 00 s : 0 . 0340 PEAK RATE : 1 . 86 cfs VOL: 1 . 04 Ac-ft TIME: 480 min BASIN ID: DOS10006 NAME : DEV TRIB AREA 1 6 MONTH STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 10 . 63 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 0 . 67 inches AREA. . : 4 . 94 Acres 5 . 69 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 83 . 80 91 . 10 TC. . . . : 36 . 74 min 36 . 74 min ABSTRACTION COEFF: 0 . 20 PEAK RATE : 0 . 07 cfs VOL: 0 . 09 Ac-ft TIME : 960 min BASIN ID: DOS30006 NAME: DEV TRIB AREA 3 6 MONTH STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 9 . 00 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 0 . 67 inches AREA. . : 8 . 20 Acres 0 . 80 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 30 98 . 00 TC. . . . : 26 .48 min 26 .48 min ABSTRACTION COEFF : 0 . 20 PEAK RATE: 0 . 07 cfs VOL: 0 . 04 Ac-ft TIME : 480 min 6/12/00 4 : 36 : 15 pm Dodds Engineers, Incorporated page 2 MAPLEWOOD PARCEL PROJECT NO. 94168 --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: OPEN6MO NAME: OPEN SPACE 6 MO STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 5 . 51 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 0 . 67 inches AREA. . : 5 . 51 Acres 0 . 00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 00 0 . 00 TC. . . . . 68 . 12 min 0 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 .4000 p2yr: 2 . 00 s : 0 . 0570 TcReach - Shallow L: 250 . 00 ks : 5 . 00 s : 0 . 0560 TcReach - Shallow L: 630 . 00 ks : 5 . 00 s : 0 . 0300 TcReach - Channel L: 670 . 00 kc : 17 . 00 s : 0 . 0240 TcReach - Channel L: 840 . 00 kc : 17 . 00 s : 0 . 0250 PEAK RATE: 0 . 01 cfs VOL: 0 . 01 Ac-ft TIME: 1330 min BIOFIL TRA TION SWALE According to the 1990 King County Surface Water Design Manual, the required flow for design of a biofiltration swale shall be equal to the 2-year outflow from the detention pond. The required bottom width of a 200' biofiltration swale was calculated by using Manning's Equation with an assumed depth of flow and 2-year outflow from the detention/water quality pond. The required flow for the biofiltration swale is 3.08 cfs. The 100-year outflow is equal to 18.70 cfs. The required bottom width of a 200' biofiltration swale was calculated by using Manning's Equation. According to the spreadsheet on the following pages, the biofiltration Swale was designed with wetland vegetation with a depth of 8 inches, an n value equal to 0.35 and a slope of 0.02. For a 200' Swale, the required bottom width is 9.35 feet. The calculated velocity is 0.41 fps which is less than the required 1.5 fps limit. The swale will be designed with a 12.5-foot bottom which exceeds the minimum. The swale was checked for conveyance capacity based on the actual design slope of 0.005, true n value equal to 0.035 and a bottom width equal to 12.5 feet. The flow depth required to carry the 100-year outflow is between 0.64 feet which is less than the design flow depth of 8 inches. The velocity of the 100-year outflow is between 2.03 fps which is less than the required 5 fps limit. 17 :1:i'll 1 10. . .... .......... . . BOTTOM ID'TI�. T SWALE GEOMETRY JOB NAME: MAPLEWOOD PARCEL BOTTOM SLOPE = 0.0200 JOB#: 94168 SIDE SLOPE (Z:1)= 3.00 OPERATOR: G.R. BROOKS MANNING'S n= 0.350 DATE: 6/13/00 DESIGN FLOW DEPTH WATER QUALITY SWALE BIOFILTRATION SWALE 3 INCHES 4 INCHES 8 INCHES (NATURAL GRASS) WETLAND VEGETATIO BOTTOM DESIGN FLOW DESIGN FLOW DESIGN FLOW WIDTH FLOW VELOCITY FLOW VELOCITY FLOW VELOCITY (FEET) (CFS) (FPS) (CFS) (FPS) (CFS) (FPS) 0.00 0.03 0.15 0.06 0.18 0.37 0.28 0.50 0.05 0.17 0.10 0.20 0.50 0.30 1.00 0.08 0.18 0.14 0.22 0.64 0.32 1.50 0.11 0.19 0.19 0.23 0.77 0.33 2.00 0.14 0.20 0.23 0.23 0.91 0.34 2.50 0.17 0.21 0.28 0.24 1.06 0.35 3.00 0.20 0.21 0.33 0.25 1.20 0.36 3.50 0.23 0.21 0.37 0.25 1.34 0.37 4.00 0.25 0.21 0.42 0.25 1.49 0.37 4.50 0.28 0.22 0.47 0.26 1.64 0.38 5.00 0.31 0.22 0.52 0.26 1.78 0.38 5.50 0.34 0.22 0.56 0.26 1.93 0.39 6.00 0.37 0.22 0.61 0.26 2.08 0.39 6.50 0.40 0.22 0.66 0.26 2.23 0.39 7.00 0.43 0.22 0.71 0.27 2.38 0.40 7.50 0.46 0.22 0.76 0.27 2.53 0.40 8.00 0.49 0.22 0.80 0.27 2.68 0.40 8.50 0.52 0.23 0.85 0.27 2.83 0.40 9.00 0.55 0.23 0.90 0.27 2.98 0.41 2�u 0.57 0.23 0.93 0.27 Le ILU 9.50 0.58 0.23 0.95 0.27 3.13 0.41 10.50 0.64 0.23 1.04 0.27 3.43 0.41 11.50 0.70 0.23 1.14 0.27 3.74 0.42 12.50 0.76 0.23 1.24 0.27 4.04 0.42 13.00 0.79 0.23 1.28 0.28 4.19 0.42 SWALE DATA: BOTTOM WIDTH (FT) = 12.50 JOB NAME: MAPLEWOOD PARCEL LEFT SIDE SLOPE (L:1) 3.00 JOB #: 94168 RIGHT SIDE SLOPE (R:l 3.00 OPERATOR: G.R. BROOKS BOTTOM SLOPE (FT/FT 0.0050 DATE: 1/28/00 MANNING'S n = 0.035 FLOW FLOW WETTED HYDRAULIC SWALE FLOW DEPTH AREA PERIMETER RADIUS CAPACITY VELOCITY (FEET) (SQ FT) (FEET) (FEET) (CFS) (FPS) 0.00 0.0000 0.0000 0.0000 0.000 0.000 0.05 0.6325 12.8162 0.0494 0.255 0.404 0.10 1.2800 13.1325 0.0975 0.814 0.636 0.15 1.9425 13.4487 0.1444 1.605 0.826 0.20 2.6200 13.7649 0.1903 2.603 0.993 0.25 3.3125 14.0811 0.2352 3.790 1.144 0.30 4.0200 14.3974 0.2792 5.156 1.283 0.35 4.7425 14.7136 0.3223 6.693 1.411 0.40 5.4800 15.0298 0.3646 8.397 1.532 0.45 6.2325 15.3460 0.4061 10.261 1.646 0.50 7.0000 15.6623 0.4469 12.285 1.755 0.55 7.7825 15.9785 0.4871 14.464 1.858 0.60 8.5800 16.2947 0.5266 16.796 1.958 0.0 9.2288 16.5477 0.5577 18.772 2.034 0.65 9.3925 16.6110 0.5654 19.282 2.053 0.71 10.3873 16.9904 0.6114 22.463 2.163 0.75 11.0625 17.2434 0.6415 1 24.704 2.233 0.80 11.9200 17.5596 0.6788 1 27.641 2.319 C. Detention Calculations All site drainage will be collected in a roadway drainage system with roof drains connected directly to the system. Some of the existing offsite tributary areas and open space will be captured and routed through the detention pond. The detention system will be sized using the detention criteria specified in the Determination of Non-Significance (Mitigated), Mitigation Measures Item 2. The stormwater release rate for the developed site shall be limited to 50% of the existing 2 year storm with a safety factor of 10% applied to the detention volume and 100% of the existing 5, 10 and 100 year storms with a safety factor of 30% applied to the detention volume. The developed 2-year, 5-year, 10-year, and 100-year, 24-hour storms were routed through the pond to confirm adequate sizing. The pond to be constructed in the field was reduced by 1/1.10 from EL 392.5 to EL 396 and reduced by 1/1.30 from EL 396 to EL 402 for calculation of the required pond volume. Since the invert of the control structure (EL 392.35) is lower than the bottom of the live storage within the pond(EL 392.5), the volume within the control structure was considered since a volume is required between the invert elevation and the pond live storage bottom for proper pond sizing. See pond volume calculations in Section IIIB of this report. See results on the following pages. Hydrographs were generated and are as specified below: Hydrograph Storm Peak Runoff Rate cfs 1 50% existing site 2-year, 24-hour storm+ open 3.09 space 2-year, 24-hour storm+ offsite trib. area 1 2-year, 24-hour storm+ offsite trib. area 3 2 existing site 5-year, 24-hour storm+ open space 7.98 5-year, 24-hour storm+ offsite trib. area 1 5-year, 24-hour storm+offsite trib. area 3 5-year, 24- hour storm 3 existing site 10-year, 24-hour storm+open space 10.49 10-year, 24-hour storm+offsite trib. area 1 10- year, 24-hour storm+ offsite trib. area 3 10-year, 24-hour storm 4 existing site 100-year, 24-hour storm+open 18.73 space 100-year, 24-hour storm+ offsite trib. area 1 100-year, 24-hour storm+ offsite trib. area 3 100- ear, 24-hour storm 5 developed site 2-year, 24-hour storm+open 12.51 space 2-year, 24-hour storm+ offsite trib. area 1 2-year, 24-hour storm+offsite trib. area 3 2-year, 24-hour storm 6 developed site 5-year, 24-hour storm+open 18.75 space 5-year, 24-hour storm+ offsite trib. area 1 5-year, 24-hour storm+ offsite trib. area 3 5-year, 24-hour storm Hydrograph Storm Peak Runoff Rate cfs 7 developed site 10-year, 24-hour storm+open 22.45 space 10-year, 24-hour storm+ offsite trib. area 1 10-year, 24-hour storm+ offsite trib. area 3 10- ear, 24-hour storm 8 developed site 100-year, 24-hour storm+ open 33.86 space 100-year, 24-hour storm + offsite trib. area 1 100-year, 24-hour storm+ offsite trib. area 3 1 00- ear, 24-hour storm 9 2-year, 24-hour outflow out of pond 3.09 10 5-year, 24-hour outflow out of pond 7.58 11 10- ear, 24-hour outflow out of pond 10.49 12 1 00- ear, 24-hour outflow out of pond 16.72 13 developed site 6-month, 24-hour storm+open 1.99 space 6-month, 24-hour storm + offsite trib. area (51,440 CF) 1 6-month, 24-hour storm+offsite trib. area 3 6- month, 24-hour storm CALCULATED POND(REVISED POND 10/3/00) VOLUME CALCULATIONS CORE#94168 PROJECT NAME:MAPLEWOOD POND 60" TOTAL ELEVATIO SURF. INCREMENTAL TOTAL LIVE MH LIVE AREA VOLUME VOLUME VOLUME VOLUME VOLUME SF CF CF CF CF CF 388.0 16868 i0 der r 37,371 �. 390.0 20503 :. 44,815 - - 392.0 24312, 82,186 12,453 . 392.5 25500 94,639 i' ' EL 392.35 392.5 23181 94,639 0 Surface Areas 3 37,178 ` ` Decreased by 1/1.10 394.0 26389 131,817 32 37,210 5 396.0 30847 189,0531 94,414 Surface Areas 72 94,486 0 ,; �� Decreased by 111.30 momm 396.0 26101 a 189,053 72 94,486 562 398.0 30104 5 50,619 111 150,730 ,374 400.0 34270 309,6321 214,993 150 215,143 Wl 72,814 402.0 38544;; , 461 287,807 1871 99411 10/3/00 1 : 39 : 40 pm Dodds Engineers, Incorporated page 2 MAPLEWOOD PARCEL PROJECT NO . 94168 Revised 10/3/00 --------------------------------------------------------------------- STAGE STORAGE TABLE CUSTOM STORAGE ID No. POND2 Description: CALCULATED POND SIZE REV. 10/3 STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- 392.35 0.0000 0.0000 394.80 60120 1.3802 397.30 131045 3.0084 399.80 208702 4.7911 392.40 1.0000 0.0000 394.90 62984 1.4459 397.40 133857 3.0729 399.90 211922 4.8651 392.50 3.0000 0.0001 395.00 65848 1.5117 397.50 136669 3.1375 400.00 215143 4.9390 392.60 2483 0.0570 395.10 68712 1.5774 397.60 139481 3.2020 400.10 218786 5.0226 392.70 4964 0.1140 395.20 71576 1.6431 397.70 142293 3.2666 400.20 222428 5.1062 392.80 7444 0.1709 395.30 74439 1.7089 397.80 145106 3.3312 400.30 226071 5.1899 392.90 9925 0.2278 395.40 77303 1.7746 397.90 147918 3.3957 400.40 229713 5.2735 393.00 12405 0.2848 395.50 80167 1.8404 398.00 150730 3.4603 400.50 233356 5.3571 393.10 14886 0.3417 395.60 83031 1.9061 398.10 153951 3.5342 400.60 236998 5.4407 393.20 17366 0.3987 395.70 85895 1.9719 398.20 157171 3.6082 400.70 240641 5.5244 393.30 19847 0.4556 395.80 88758 2.0376 398.30 160392 3.6821 400.80 244283 5.6080 393.40 22327 0.5126 395.90 91622 2.1034 398.40 163613 3.7560 400.90 247926 5.6916 393.50 24808 0.5695 396.00 94486 2.1691 398.50 166833 3.8300 401.00 251569 5.7752 393.60 27288 0.6264 396.10 97298 2.2337 398.60 170054 3.9039 401.10 255211 5.8588 393.70 29769 0.6834 396.20 100110 2.2982 398.70 173275 3.9778 401.20 258854 5.9425 393.80 32249 0.7403 396.30 102923 2.3628 398.80 176495 4.0518 401.30 262496 6.0261 393.90 34730 0.7973 396.40 105735 2.4273 398.90 179716 4.1257 401.40 266139 6.1097 394.00 37210 0.8542 396.50 108547 2.4919 399.00 182937 4.1996 401.50 269781 6.1933 394.10 40074 0.9200 396.60 111359 2.5565 399.10 186157 4.2736 401.60 273424 6.2769 394.20 42938 0.9857 396.70 114171 2.6210 399.20 189378 4.3475 401.70 277066 6.3606 394.30 45801 1.0515 396.80 116984 2.6856 399.30 192598 4.4215 401.80 280709 6.4442 394.40 48665 1.1172 396.90 119796 2.7501 399.40 195819 4.4954 401.90 284351 6.5278 394.50 51529 1.1829 397.00 122608 2.8147 399.50 199040 4.5693 402.00 287994 6.6114 394.60 54393 1.2487 397.10 125420 2.8793 399.60 202260 4.6433 394.70 57257 1.3144 397.20 128232 2.9438 399.70 205481 4.7172 10/19/00 12 : 5 : 5 am Dodds Engineers, Incorporated page 1 MAPLEWOOD PARCEL PROJECT NO. 94168 Revised 10/3/00 --------------------------------------------------------------------- --------------------------------------------------------------------- HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf\AcFt Acres --------------------------------------------- --------------------------------------------- 1 3 . 085 540 126406 cf 73 . 84 2 7 . 976 490 293685 cf 73 . 84 3 10 . 487 490 363460 cf 73 . 84 4 18 . 728 490 585580 cf 73 . 84 5 12 . 505 490 300517 cf 73 . 84 6 18 . 745 490 436156 cf 73 . 84 7 22 .445 490 516065 cf 73 . 84 8 33 . 861 490 761736 cf 73 . 84 9 3 . 090 1000 300631 cf 73 . 84 10 7 . 579 670 436318 cf 73 . 84 11 10 .493 600 516225 cf 73 . 84 12 16 . 720 590 761902 cf 73 . 84 13 1 . 988 490 51440 cf 73 . 84 10/19/00 12 : 8 :23 am Dodds Engineers, Incorporated page 1 MAPLEWOOD PARCEL PROJECT NO. 94168 Revised 10/3/00 --------------------------------------------------------------------- STAGE DISCHARGE TABLE COMBINATION DISCHARGE ID No . COME02 Description: COMBO REV. 10/3 Structure : ORIFICE2 Structure : Structure : RISER2 Structure : Structure : STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 392.35 0.0000 394.80 2.3499 397.30 8.1983 399.80 18.787 392.40 0.3357 394.90 2.3974 397.40 9.8266 399.90 19.059 392.50 0.5815 395.00 2.4440 397.50 10.424 400.00 19.327 392.60 0.7507 395.10 2.4897 397.60 10.955 400.10 19.591 392.70 0.8882 395.20 2.5345 397.70 11.455 400.20 19.851 392.80 1.0071 395.30 2.5786 397.80 11.929 400.30 20.107 392.90 1.1134 395.40 2.6219 397.90 12.380 400.40 20.360 393.00 1.2104 395.50 2.6646 398.00 12.812 400.50 20.610 393.10 1.3002 395.60 2.7065 398.10 13.227 400.60 20.857 393.20 1.3842 395.70 2.7479 398.20 13.628 400.70 21.100 393.30 1.4633 395.80 2.7886 398.30 14.014 400.80 21.341 393.40 1.5384 395.90 2.8287 398.40 14.389 400.90 21.578 393.50 1.6100 396.00 2.8683 398.50 14.753 401.00 21.813 393.60 1.6785 396.10 2.9073 398.60 15.106 401.10 22.046 393.70 1.7444 396.20 2.9458 398.70 15.451 401.20 22.275 393.80 1.8078 396.30 2.9838 398.80 15.787 401.30 22.503 393.90 1.8691 396.40 3.0214 398.90 16.115 401.40 22.728 394.00 1.9285 396.50 3.0584 399.00 16.436 401.50 22.950 394.10 1.9861 396.60 3.0951 399.10 16.750 401.60 23.171 394.20 2.0420 396.70 3.1313 399.20 17.057 401.70 23.389 394.30 2.0965 396.80 3.1670 399.30 17.359 401.80 23.605 394.40 2.1496 396.90 3.5330 399.40 17.655 401.90 23.819 394.50 2.2014 397.00 4.3530 399.50 17.945 402.00 24.031 394.60 2.2520 397.10 5.4365 399.60 18.231 394.70 2.3015 397.20 6.7283 399.70 18.511 10/3/00 1 : 39 : 40 pm Dodds Engineers, Incorporated page 4 MAPLEWOOD PARCEL PROJECT NO . 94168 Revised 10/3/00 --------------------------------------------------------------------- --------------------------------------------------------------------- STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. ORIFICE2 Description: ORIFICE REV. 10/3 Outlet Elev: 392 . 35 Elev: 390 . 35 ft Orifice Diameter: 7 . 4380 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 392.35 0.0000 394.80 2.3499 397.30 3.3402 399.80 4.0978 392.40 0.3357 394.90 2.3974 397.40 3.3738 399.90 4.1252 392.50 0.5815 395.00 2.4440 397.50 3.4070 400.00 4.1525 392.60 0.7507 395.10 2.4897 397.60 3.4400 400.10 4.1795 392.70 0.8882 395.20 2.5345 397.70 3.4726 400.20 4.2064 392.80 1.0071 395.30 2.5786 397.80 3.5049 400.30 4.2331 392.90 1.1134 395.40 2.6219 397.90 3.5369 400.40 4.2596 393.00 1.2104 395.50 2.6646 398.00 3.5686 400.50 4.2860 393.10 1.3002 395.60 2.7065 398.10 3.6000 400.60 4.3122 393.20 1.3842 395.70 2.7479 398.20 3.6312 400.70 4.3383 393.30 1.4633 395.80 2.7886 398.30 3.6621 400.80 4.3642 393.40 1.5384 395.90 2.8287 398.40 3.6928 400.90 4.3899 393.50 1.6100 396.00 2.8683 398.50 3.7232 401.00 4.4155 393.60 1.6785 396.10 2.9073 398.60 3.7533 401.10 4.4410 393.70 1.7444 396.20 2.9458 398.70 3.7832 401.20 4.4663 393.80 1.8078 396.30 2.9838 398.80 3.8129 401.30 4.4914 393.90 1.8691 396.40 3.0214 398.90 3.8423 401.40 4.5165 394.00 1.9285 396.50 3.0584 399.00 3.8716 401.50 4.5413 394.10 1.9861 396.60 3.0951 399.10 3.9006 401.60 4.5661 394.20 2.0420 396.70 3.1313 399.20 3.9293 401.70 4.5907 394.30 2.0965 396.80 3.1670 399.30 3.9579 401.80 4.6152 394.40 2.1496 396.90 3.2024 399.40 3.9863 401.90 4.6396 394.50 2.2014 397.00 3.2374 399.50 4.0145 402.00 4.6638 394.60 2.2520 397.10 3.2721 399.60 4.0424 394.70 2.3015 397.20 3.3063 399.70 4.0702 10/3/00 1 : 39 :40 pm Dodds Engineers, Incorporated page S MAPLEWOOD PARCEL PROJECT NO. 94168 Revised 10/3/00 STAGE DISCHARGE TABLE RISER DISCHARGE ID No. RISER2 Description: RISER REV. POND 10/3 Riser Diameter (in) : 18 . 00 elev: 396 . 82 ft Weir Coefficient . . . : 9 . 739 height : 402 . 00 ft Orif Coefficient . . . : 3 . 782 increm: 0 . 10 ft STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 396.82 0.0000 398.20 9.9964 399.60 14.188 401.00 17.398 396.90 0.3306 398.30 10.352 399.70 14.441 401.10 17.605 397.00 1.1156 398.40 10.696 399.80 14.690 401.20 17.809 397.10 2.1644 398.50 11.030 399.90 14.934 401.30 18.011 397.20 3.4220 398.60 11.353 400.00 15.175 401.40 18.211 397.30 4.8581 398.70 11.668 400.10 15.411 401.50 18.409 397.40 6.4528 398.80 11.974 400.20 15.645 401.60 18.604 397.50 7.0171 398.90 12.273 400.30 15.874 401.70 18.798 397.60 7.5154 399.00 12.564 400.40 16.101 401.80 18.990 397.70 7.9826 399.10 12.849 400.50 16.324 401.90 19.179 397.80 8.4240 399.20 13.128 400.60 16.544 402.00 19.367 397.90 8.8433 399.30 13.401 400.70 16.762 398.00 9.2437 399.40 13.668 400.80 16.976 398.10 9.6274 399.50 13.931 400.90 17.188 10/3/00 1 : 39 :41 pm Dodds Engineers, Incorporated page 6 MAPLEWOOD PARCEL PROJECT NO . 94168 Revised 10/3/00 --------------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> OUTFLOW STORAGE <--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (Cf) 2 YR ......................... 3.09 12.51 POND2 COMB02 396.59 9 3.09 3 ac-ft 5 YR ......................... 7.98 18.74 POND2 COMB02 397.26 10 7.58 3 ac-ft 10 YR ........................ 10.49 22.45 POND2 COMB02 397.51 11 10.49 3 ac-ft 100 YR ....................... 18.73 33.86 POND2 COMB02 399.09 12 16.72 4 ac-ft The routing results are summarized as follows: ROUTING RESULTS 2 year 5-year 10 year 100 year storm storm storm storm Qp allowable release from site (cfs) 3.09 7.98 10.49 18.73 (adjusted 2 yr outflow by 50%) Hydrographs 1, 2, 3, 4 Qp developed(cfs) 12.51 18.75 22.45 33.86 Hydrographs 5, 6, 7, 8 Qp out of pond (cfs) 3.09 7.58 10.49 16.72 Hydrographs 9, 10, 11, 12 Pond live storage required CF 111,000 129,861 137,034 185,850 Pond live storage provided (CF)w/ 125,495 149,986 159,125 222,666 safety factor of 10% for 2-yr and 30% for remaining storms See attached volume calculations spreadsheet for the actual pond to be constructed on the following page. Design of the emergency overflow spillway for the pond is calculated below. The maximum water surface is at EL 399.09. The spillway will be placed at EL 400.09 with a berm located at EL 402.0. The depth of water over the spillway will be 0.70 feet. The overflow elevation therefore will be equal to 400.09 plus 0.70 or 400.79. L=(QIOW(3.21H3i2)) - 2AH L = (33.86/(3.21(0.7)3/2)) - 2.4(0.7) = 16.3 feet minimum => USE 16.5 feet A minimum of 0.3 feet of freeboard above the overflow elevation is required. Therefore, the berm height for the pond needs to be greater than or equal to 400.79 plus 0.3 or 401.09. The actual berm height for the pond is 402.0 which is equal to the minimum. POND TO BE CONSTRUCTED (REVISED POND 10/3/00) VOLUME CALCULATIONS CORE # 94168 PROJECT NAME: MAPLEWOOD 11 POND POND 60" TOTAL ELEVATION SURF. INCREMENTAL TOTAL LIVE MH LIVE AREA VOLUME VOLUME VOLUME VOLUME VOLUME SF CF CF CF CF CF 388.0 16868 0 37,371 390.0 20503 37,371 44,815 392.01 24312 82,186 12,453 EL 392.35 392.51 25500 94,639 0 3 3 40,896 394.0 m 135,535 40,896 32 40,928 62,960 396.0 3393211111111M 198,495 103,856 72 103,928 73,068 398.01 39136 271,563 176,924 111 177,035 83,688 400.0 44552 355,251 260,612 150 260,762 94,660 402.0 50108 449,9111 355,2721 1871 355,459 10/3/00 1 : 39 :40 pm Dodds Engineers, Incorporated. page 1 MAPLEWOOD PARCEL PROJECT NO. 94168 Revised 10/3/00 --------------------------------------------------------------------- --------------------------------------------------------------------- STAGE STORAGE TABLE CUSTOM STORAGE ID No. PNDREAL2 Description: REAL POND SIZE REV. 10/3 STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --AC-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 392.35 0.0000 0.0000 394.80 66128 1.5181 397.30 151448 3.4768 399.80 252389 5.7941 392.40 1.0000 0.0000 394.90 69278 1.5904 397.40 155103 3.5607 399.90 256576 5.8902 392.50 3.0000 0.0001 395.00 72428 1.6627 397.50 158759 3.6446 400.00 260762 5.9863 392.60 2731 0.0627 395.10 75578 1.7350 397.60 162414 3.7285 400.10 265497 6.0950 392.70 5460 0.1253 395.20 78728 1.8073 397.70 166069 3.8124 400.20 270232 6.2037 392.80 8188 0.1880 395.30 81878 1.8797 397.80 169725 3.8963 400.30 274967 6.3124 392.90 10916 0.2506 395.40 85028 1.9520 397.90 173380 3.9803 400.40 279701 6.4211 393.00 13645 0.3132 395.50 88178 2.0243 398.00 177036 4.0642 400.50 284436 6.5298 393.10 16373 0.3759 395.60 91328 2.0966 398.10 181222 4.1603 400.60 289171 6.6385 393.20 19101 0.4385 395.70 94478 2.1689 398.20 185408 4.2564 400.70 293906 6.7472 393.30 21830 0.5011 395.80 97628 2.2412 398.30 189594 4.3525 400.80 298641 6.8558 393.40 24558 0.5638 395.90 100778 2.3135 398.40 193781 4.4486 400.90 303376 6.9645 393.50 27286 0.6264 396.00 103928 2.3859 398.50 197967 4.5447 401.00 308111 7.0732 393.60 30015 0.6890 396.10 107583 2.4698 398.60 202153 4.6408 401.10 312845 7.1819 393.70 32743 0.7517 396.20 111239 2.5537 398.70 206340 4.7369 401.20 317580 7.2906 393.80 35471 0.8143 396.30 114894 2.6376 398.80 210526 4.8330 401.30 322315 7.3993 393.90 38200 0.8769 396.40 118550 2.7215 398.90 214712 4.9291 401.40 327050 7.5080 394.00 40928 0.9396 396.50 122205 2.8054 399.00 218899 5.0252 401.50 331785 7.6167 394.10 44078 1.0119 396.60 125860 2.8894 399.10 223085 5.1213 401.60 336520 7.7254 394.20 47228 1.0842 396.70 129516 2.9733 399.20 227271 5.2174 401.70 341254 7.8341 394.30 50378 1.1565 396.80 133171 3.0572 399.30 231458 5.3135 401.80 345989 7.9428 394.40 53528 1.2288 396.90 136826 3.1411 399.40 235644 5.4096 401.90 350724 8.0515 394.50 56678 1.3011 397.00 140482 3.2250 399.50 239830 5.5057 402.00 355459 8.1602 394.60 59828 1.3735 397.10 144137 3.3089 399.60 244017 5.6019 394.70 62978 1.4458 397.20 147793 3.3928 399.70 248203 5.6980 • l� �n���w�o�o��rnw�w�•rr�.��wi � ����i���ii1i YIYi���.•��i�Nf���J�i ��1■YMA �WZJFdrMA AM./s��'���������Q ®�=�I/>J1 MFAMPi • / ii���ii�—�I���N�M� /i•. I I/II/tl—•���iA. /�//I/I/Il�����'wiil�il�� I/I'I/�I�l���.Y� /M=IR��� VLr���w�s������w��� B. , a .- `. �t KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL FIGURE 4.35C HEADWATER DEPTH FOR SMOOTH INTERIOR PIPE CULVERTS WITH INLET CONTROL ISO 10,000 168 8,000 EXAMPLE ENTRANCE TYPE 6. 156 6,000 Di42 inches (3.5 fast) 6_ SQUARE EDGE WITH 5,000 0.120 cfa 5. l44 HEADWALL 4,000 • 6 5. 132 o feet 4. 3,000 (1) 2.5 0.8 5' 4, 120 i (2) 2.1 7.4 1 1 2,000 108 (3) 2.2 7.7 3. I ND in feet — 3 — 96 1,000 3 PLAN GROOVE END WITH B00 HEADWALL 600 2: 500 1 I 72 400 ` 1A 3 = P 300 1.5 = 60 U. 200 / 1.- 1.5 PLAN \/ 2) GROOVEEND c 5a a �i a PROJECTING cc /W 100 Z > 48 / 80 D 042 60 IL 1.0 1.0 _� � • W C c HW SCALE ENTRANCE 1.0 tz .�/ /r0 p TYPE cc W W 36 .9 9 30 (1) Square edge with 9 .9 W 33 headwall a a C 2Q (2) Grooveend with W 30 headwall 2 .8 .8 (3) Groove and •8 27 projecting t0 24 8 , T .7- �}W —ICf 6 To use scale (2)or (3) project > Z 21 5 horizontally to scale(1),then r�r Dd" 4 use straight inclined line through D and Q scale%.or reverse as 6 3 illustrated. .6 .6 c FS 2 (? 33.96 cam\ 15 5 .5 11.0 .5 12 i I i I 4.35-11 1/90