Loading...
PZ - Storm Drainage Calcs Storm Drainage Master for Rosalyn Subdivision Client: B-B Rosalyn, LLC 2400 W. Wapoot Drive Meridian, ID 83646 Mason & associates 1„�. Professional Engineers, Land Surveyors and Planners 9243rd St. So., Suite 8, Nampa, ID 83651 Ph (208) 454-0256 Job No. JY0322 Date: October 9, 2023 MAL F y 9212 "W J. Dcvbc✓ \ "1a23 Mason fy A55ociatc5j.4 JY0322SD.xlsx Cover 1 of 2 CALCULATION METHODOLOGY FLOW CALCULATIONS Flow for the basin areas are calculated using the Rational Method. The"C"coefficient used in the calculations is based on weighted values as shown. Conveyance facilities are designed for a 25-year return frequency storm and the worst case condition between 10 minutes and 1 hour. The worst case storm for flow is the 10-minute duration. HYDRAULIC GRADE CALCULATIONS These calculations employ the Manning Equation. The hydraulic grade is based on calculated flow. EQUATIONS USED IN CALCULATIONS RATIONAL METHOD Q=CiA where: Q = Runoff Rate, cfs C = Runoff Coefficient i = Storm Intensity, in./hr. A= Basin Area(s), acres MANNING EQUATION V=1.49R213S112/n where: V= Velocity, fps R = Hydraulic Radius, ft. S = Channel Slope, ft./ft. n = Manning Roughness Coefficient Mason Fy Associates 1� JY0322SD.xlsx Cover 2 of 2 PEAK FLOW CALCULATIONS FOR SUB-BASINS POST-DEVELOPED RUNOFF COEFFICIENT (C) = 0.80 Area 1 weighted landscape/roof/asphalt LOT TRAVEL TIME = 2.3 min DROP INLET CAPACITIES: VERTICAL CURB = 4.26 cfs (depth at top of curb) ROLLED CURB = 3.15 cfs (depth at top of curb) Location AREA DATA CALCULATIONS SUB-BASIN SUB-BASIN CURB GUTTER AVERAGE GUTTER GUTTER TOTAL 50yr AREA AREA TYPE LENGTH GUTTER TIME CAPACITY TIME I Q # ac (V,R) it SLOPE min cfs Tc in/hr cfs 1 0.39 R 180 1.30% 1.0 3.11 10.0 3.1SI 0.99 Mason Fy Associates JY0322SD.xlsx Conveyance SAND AND GREASE TRAP CALCULATION BASIN: 1 SEDIMENT/GREASE TRAP SIZING S&G TRAP DETENTION TIME NUMBER OF TANKS 1 NUMBER OF TANKS 1 DISCHARGE (CFS) 0.99 DISCHARGE(CFS) 0.99 VELOCITY-MAXIMUM(FPS) 0.50 S&G STORAGE VOLUME(CF) 152.00 REQUIRED THROAT AREA(SF) 1.98 DETENTION TIME,T(SEC) 154 TANK SIZE(gal) 1,000 IS T>40 SEC.? YES TANK WIDTH(FT) 4.00 THROAT-WIDTH(in) 12 VELOCITY-ACTUAL(fps) 0.25 Pipe Capacity- min. pipe slope req'd Area 1 Pipe Size, in., variable 12 0 0 Pipe Slope, %, variable 0.22% 0,22% 0.22% Mannings, n, variable PVC 0.009 0.009 0.009 Pipe Capacity, cfs 2.41 0.00 0.00 Mason& Associates 1, JY0322S D.xlsx Conveyance RETENTION BASIN AREA NO.1 WORST CASE STORM VOLUME,100-yr BASIN AREA 0.39 acres RUNOFF COEFFICIENT(C) 0.80 weighted coefficient PERCOLATION RATE 8.00 in/hr PERCOLATIONAREA 592 sf SYSTEM VOID SPACE 916 cf OFFSITE DISCHARGE 0 cfs Runoff Coefficient c Area(sf) Area(ac) weighted Area Roof= 0.95 6652 0.15 0.15 Asphalt= 0.9 7438 0.17 0.15 Landscape= 0.2 3041 0.07 0.01 Total= 0.39 0.31 weighted"c"factor= 0.80 PEAK MIN. 100 YR PEAK LESS FLOW VOIDS PERC POND DURATION DURATION INTENSITY' FLOW DISCH. VOLUME VOLUME VOLUME VOLUME (min) (hrs) (inlhp (dr) (cfs) (c0 (c) (c9 (of) 10 0.17 3.11 0.973 0.973 584 916 66 0 15 0.25 2.62 0.819 0.819 737 916 99 0 30 0.50 1.82 0.569 0.569 1,024 916 197 0 60 1.00 1.15 0.360 0.360 1,295 916 395 0 RETENTION BASIN AREA NO.1 TOTAL STORAGE REQ'D= 1,295 cf WORST CASE STORM DURATION 60 minutes OFFSITE DISCHARGE 0.00 cfs SWALE VOLUME CALCULATION SWALE TOP AREA= F1000 sf SWALE BOTTOM AREA= sf SWALE AVE.END AREA= sf SWALE DEPTH= ft SWALE STORAGE= 0 cf SWALE INFILTRATION= 0 cf PIPE VOLUME CALCULATION PIPE AREA 24"DIA= F-771741 sf PIPE LENGTH= 105 sf PIPE BARRELS= 0.00 PIPE STORAGE= 0 cf INFILTRATION BED CALCULATION W L INFILTRATION AREA 592 sf ROCK 8 29 ROCK BED DEPTH= []inlhf ft SAND 8 29 SAND BED DEPTH= ft VOID SPACE IN SAND= VOID SPACE IN DRAIN ROCK= PERCOLATION RATE= VOLUME IN VOIDS= 916 cf PERCOLATION VOLUME= 395 cf INFILTRATION BED STORAGE= 1311 cf TOTAL STORED VOLUME_ 1311 cf > 1295 cf THEREFORE STORAGE IS ADEQUATE TIME REQUIRED TO DISSIPATE VOLUME TIME 1 hours Ma5on& A"e baresij JY0322SD.xlsx ED Area 1 1 of 1 This Document, and the Concepts, Ideas and Design Incorporated herein are an instrument of professional services and are the Property of Mason and Associates, Inc., therefore they are not to be used in whole or part for any other project without the express Written Authorization of Mason and Associates, Inc.© a 0 10 20 40 Scale: 1'=20' p� SNOISIA3H N I � I I I a I � y m i I o m m i sl a + a x. , 1.San sa Fr s°0° 'o° I I ya --- m O isoosor1i 4 wj STORM DRAIN AREA HARD SURFACE: 7,436 SF w C U ROOF AREA:6,652 SF 0 LANDSCAPE:3,041 SF / +` LONGEST RUN:115' / 4Q ———————— ——— -- N N AVERAGE SLOPE:IJR 5°r a ] t t u � 8 ___ wmv'aaw = c'j LL1 N b� f - f==----______________ _____- ---- -- J - ————— r EAST ROSALttJ DRIVE o z 0- z � 0 W N ¢ o 0 W