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Stormwater Runoff Calcs 12-19-05 Larson Engineering of Minnesota 3524 Labore Road White Bear Lake. MN 55110-5100 651.481.9120 Fax: 651.481.9201 www.larsonengr.com ~ Larson MINNETONKA WEST MIDDLE SCHOOL STORMWATER RUNOFF CALCULATIONS BY LARSON ENGINEERING OF MINNESOTA DECEMBER 19, 2005 CONTENTS: 1. Stormwater Summary 2. HYDROCAD report for new site conditions (1-year, 1 O-year and 1 DO-year events) 3. Drainage area map Larson Engineering of Minnesota 3524 Labore Road White Bear Lake, MN 55110-5100 651.481.9120 Fax: 651.481.9201 www.larsonengr.com 51 Larson MINNETONKA WEST MIDDLE SCHOOL SUMMARY OF STORMWATER RUNOFF Feature Peak Runoff Rates 1-yr Event 10-yr Event 1 OO-yr event 0.63 cfs 3.61 cfs 4.13 cfs Filtration Basin The stormwater runoff from the site will enter a new filtration basin for rate and quality control. The filtration basin will use draintile to assure adequate drawdown times and allow for increased usability of the grassed area. The filtration basin will discharge to the discharge to the MNDOT drainage ditch along highway 41 through an 8" PVC pipe. The discharge rates for the 10-year and 1 OO-year rainfall events are below the maximum rate of 5 cfs allowed by MNDOT. A.'.. v 4!;Si.).. -.,-.,",',,-. ,-..".".}, 11 I A.es. A...................... /'06+';,'. <l "'~"""" '1'; ~ <c. 18" ~c Filtration Basin ~ ~ ~"..../.,,. ..",.,....""..,.... ~~~c,~ A'<.e,;.. ".on '." ,. "'d'.'.. .. ....-.....,..' ~."..;,. ~i!i~ &'CB "4:; <l """,' 12"\ J ~ ~ J /,..:. ~" ~ ,...'.. ~ a'. i:TB,;, ,'d"3".".,, 4" DT 12" RC~ IJJS\ ~tB} Drainage Diagram for Runoff Calculations - Filtration Prepared by Larson Engineering 12/19/2005 HydroCAD@7.10 sin 001935 @2005 HydroCAD Software Solutions LLC Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 1-yr Rainfal/=2.40" Page 2 12/19/2005 Runoff Subcatchment A: = 0.13 cfs @ 12.22 hrs, Volume= 0.013 af, Depth> 0.55" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 1-yr Rainfall=2.40" Area (ac) 0.286 CN Description 74 >75% Grass cover, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 25.0 220 0.0110 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" Runoff Subcatchment B: = 2.46 cfs @ 12.43 hrs, Volume= 0.304 af, Depth> 1.28" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 1-yr Rainfall=2.40" Area (ac) 1.170 1.674 2.844 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) ( cfs) 38.0 250 0.0050 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 3.0 50 0.1100 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 2.9 350 0.0100 2.0 Shallow Concentrated Flow, Paved Kv= 20.3 fps 43.9 650 Total Runoff Subcatchment C: = 0.32 cfs @ 11.94 hrs, Volume= 0.014 af, Depth> 1.52" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 1-yr Rainfall=2.40" Area (ac) 0.032 0.078 0.110 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 91 Weighted Average Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAO@ 7.10 sIn 001935 @ 2005 HydroCAO Software Solutions LLC Type 1/24-hr 1-yr Rainfal/=2.40" Page 3 12/19/2005 Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 2.6 25 0.0400 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.9 80 0.0290 1.4 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 3.5 105 Total Subcatchment 0: Runoff 0.37 cfs @ 11.98 hrs, Volume= 0.018 af, Depth> 1.04" = Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 1-yr Rainfall=2.40" Area (ac) 0.115 0.089 0.204 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 84 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftlsec) (cfs) 6.2 85 0.0530 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.3 25 0.0600 1.5 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 6.5 110 Total Subcatchment E: Runoff 0.08 cfs @ 11.90 hrs, Volume= 0.003 af, Depth> 2.17" = Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 1-yr Rainfall=2.40" Area (ac) 0.019 CN Description 98 Impervious Subcatchment F: Runoff 0.41 cfs @ 11.98 hrs, Volume= 0.019 af, Depth> 0.87" = Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 1-yr Rainfall=2.40" Area (ac) 0.192 0.073 0.265 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 81 Weighted Average Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 1-yr Rainfal/=2.40" Page 4 12/19/2005 Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 4.6 70 0.0780 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 1.3 110 0.0230 1.4 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 5.9 180 Total Subcatchment G: Runoff = 2.49 cfs @ 12.03 hrs, Volume= 0.137 af, Depth> 0.98" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 1-yr Rainfall=2.40" Area (ac) 1.064 0.613 1.677 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 83 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) ( ftIft) (ftIsec) (cfs) 1.1 60 0.0100 0.9 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 5.8 48 0.0200 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 3.1 64 0.1700 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.4 25 0.0200 1.0 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 10.4 197 Total Inflow Area = Inflow = Outflow = Discarded = Primary = Pond 1: 4" DT 0.286 ac, Inflow Depth> 0.55" 0.13 cfs @ 12.22 hrs, Volume= 0.13 cfs @ 12.22 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.13 cfs @ 12.22 hrs, Volume= for 1-yr event 0.013 af 0.013 af, Atten= 0%, Lag= 0.0 min 0.000 af 0.013 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 55.99' @ 12.22 hrs Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass del. time= 0.0 min ( 891.8 - 891.8 ) Device #1 Routing Primary #2 Discarded Invert Outlet Devices 55.67' 4.0" x 425.0' long Culvert CPP, projecting, no headwall, Ke= 0.900 Outlet Invert= 40.13' S= 0.0366 'f Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior 56.77' 50.0'long x 20.0' breadth Broad-Crested Rectangular Weir Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@7.10 sIn 001935 @2005 HydroCAD Software Solutions LLC Type 1/24-hr 1-yr Rainfal/=2.40" Page 5 12/19/2005 Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Discarded OutFlow Max=O.OO cfs @ 0.00 hrs HW=55.67' (Free Discharge) L2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) Primary OutFlow Max=0.13 cfs @ 12.22 hrs HW=55.99' (Free Discharge) L1=Culvert (Inlet Controls 0.13 cfs @ 1.5 fps) Inflow Area = Inflow = Outflow = Primary = Pond 2: 12" RCP 3.130 ac, Inflow Depth> 1.21" 2.54 cfs @ 12.43 hrs, Volume= 2.54 cfs @ 12.43 hrs, Volume= 2.54 cfs @ 12.43 hrs. Volume= tor 1-yr event 0.317 at 0.317 at, Atten= 0%, Lag= 0.0 min 0.317 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 41.08' @ 12.43 hrs Flood Elev= 48.63' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass del. time= 0.0 min (853.8 - 853.8) Device #1 Routing Pri mary Invert Outlet Devices 40.13' 12.0" x 59.0'lon9 Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 39.35' S= 0.0132 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=2.55 cfs @ 12.43 hrs HW=41.08' (Free Discharge) L1=Culvert (Inlet Controls 2.55 cfs @ 3.3 tps) Inflow Area = Inflow = Outflow = Primary = Pond 3: 12" RCP 3.240 ac, Inflow Depth> 1.22" 2.57 cts @ 12.40 hrs, Volume= 2.57 cfs @ 12.40 hrs, Volume= 2.57 cfs @ 12.40 hrs, Volume= for 1-yr event 0.331 at 0.331 af, Atten= 0%, Lag= 0.0 min 0.331 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 40.31' @ 12.40 hrs Flood Elev= 48.65' Plug-Flow detention time= 0.0 min calculated for 0.331 af (100% of inflow) Center-ot-Mass del. time= (not calculated: outflow precedes inflow) Device Routing #1 Primary I nvert Outlet Devices 39.35' 12.0" x 100.0'lon9 Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 38.20' S= 0.0115 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=2.58 efs @ 12.40 hrs HW=40.31 , (Free Discharge) L1=Culvert (Inlet Controls 2.58 efs @ 3.3 fps) Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sin 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 1-yr Rainfal/=2.40" Page 6 12/19/2005 I nflow Area = Inflow = Outflow = Primary = Pond 4: 12" 3.444 ac, Inflow Depth> 1.21" 2.61 cfs @ 12.40 hrs, Volume= 2.61 cfs @ 12.40 hrs, Volume= 2.61 cfs @ 12.40 hrs, Volume= for 1-yr event 0.348 af 0.348 af, Atten= 0%, Lag= 0.0 min 0.348 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 39.85' @ 12.40 hrs Flood Elev= 44.42' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= (not calculated: outflow precedes inflow) Device Routing #1 Primary #2 Primary Invert Outlet Devices 38.20' 12.0" x 108.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 38.10' S= 0.0009 'f Cc= 0.900 n= 0.012 Concrete pipe, finished 44.42' 20.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coet. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=2.61 cfs @ 12.40 hrs HW=39.85' (Free Discharge) t1=culvert (Barrel Controls 2.61 cfs @ 3.3 fps) 2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) Inflow Area = Inflow = Outflow = Primary = Pond 5: 12" 0.019 ac, Inflow Depth> 2.17" 0.08 cfs @ 11.90 hrs, Volume= 0.08 cfs @ 11.90 hrs, Volume= 0.08 cfs @ 11.90 hrs, Volume= for 1-yr event 0.003 af 0.003 af, Atten= 0%, Lag= 0.0 min 0.003 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 37.92' @ 11.90 hrs Flood Elev= 41.21' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= (not calculated: outflow precedes inflow) Device #1 Routing Primary Invert Outlet Devices 37.75' 12.0" x 56.0'long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 37.55' S= 0.0036 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=0.07 cfs @ 11.90 hrs HW=37.91, (Free Discharge) 't...1=Culvert (Barrel Controls 0.07 cfs @ 1.3 fps) Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 1-yr Rainfal/=2.40" Page 7 12/19/2005 Inflow Area = Inflow = Outflow = Primary = Pond 6: 18" PVC 3.728 ac, Inflow Depth> 1.19" 2.67 cfs @ 12.39 hrs, Volume= 2.67 cfs @ 12.39 hrs, Volume= 2.67 cfs @ 12.39 hrs, Volume= for 1-yr event 0.371 af 0.371 af, Atten= 0%, Lag= 0.0 min 0.371 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 38.42' @ 12.39 hrs Flood Elev= 42.46' Plug-Flow detention time= 0.0 min calculated for 0.371 af (100% of inflow) Center-of-Mass det. time= 0.0 min ( 850.3 - 850.3 ) Device Routing #1 Primary Invert Outlet Devices 37.55' 18.0" x 72.0' long Culvert CPP, square edge headwall, Ke= 0.500 Outlet Invert= 37.29' S= 0.0036 'f Cc= 0.900 n= 0.010 PVC, smooth interior Primary OutFlow Max=2.66 cfs @ 12.39 hrs HW=38.42' (Free Discharge) L1=Culvert (Barrel Controls 2.66 cfs @ 3.6 fps) Inflow Area = Inflow = Outflow = Primary = Pond 7: Filtration Basin 5.405 ac, Inflow Depth> 1.13" 4.13 cfs @ 12.02 hrs, Volume= 0.63 cfs @ 13.58 hrs, Volume= 0.63 cfs @ 13.58 hrs, Volume= for 1-yr event 0.507 af 0.415 af, Atten= 85%, Lag= 94.2 min 0.415 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 36.75' @ 13.58 hrs Surf.Area= 7,612 sf Storage= 11,211 cf Plug-Flow detention time= 246.3 min calculated for 0.415 af (82% of inflow) Center-of-Mass det. time= 169.7 min ( 1,018.9 - 849.2) Volume #1 Invert Avail.Storage Storage Description 35.00' 58,556 cf Custom Stage Data (Pyramidal) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum. Store Wet.Area (feet) (sq-ft) (cubic-feet) (cubic-feet) (sq-ft) 35.00 5,350 0 0 5,350 36.00 6,500 5,916 5,916 6,540 37.00 8,000 7,237 13,153 8,078 38.00 9,550 8,764 21,916 9,673 39.00 11,200 10,364 32,280 11,373 40.00 13,150 12,162 44,442 13,372 41.00 15,100 14,114 58,556 15,379 Device Routing Invert Outlet Devices #1 Primary 33.00' 8.0" x 80.0'long Culvert CPP, square edge headwall, Ke= 0.500 Outlet Invert= 23.00' S= 0.1250 'f Cc= 0.900 n= 0.010 PVC, smooth interior #2 Device 1 34.00' 4.0" X 88.0' long Culvert X 3.00 Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@7.10 sIn 001935 @2005 HydroCAD Software Solutions LLC Type 1/24-hr 1-yr Rainfal/=2.40" Page 8 12/19/2005 #3 Device 2 CPP, projecting, no headwall, Ke= 0.900 Outlet Invert= 33.00' S= 0.0114 'f Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior 35.00' 12.000 inlhr Exfiltration over Surface area above invert Excluded Surface area = 5,350 sf 37.00' 24.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 Primary OutFlow Max=0.63 cfs @ 13.58 hrs HW=36.75' (Free Discharge) L1=Culvert (Passes 0.63 cfs of 3.11 cfs potential flow) t2=culvert (Passes 0.63 cfs of 0.71 cfs potential flow) L3=Exfiltration (Exfiltration Controls 0.63 cfs) 4=Orifice/Grate (Controls 0.00 cfs) Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 10-yr Rainfal/=4.20" Page 9 12/19/2005 Runoff Subcatchment A: = 0.48 cfs @ 12.19 hrs, Volume= 0.041 af, Depth> 1.73" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.20" Area (ac) 0.286 CN Description 74 >75% Grass cover, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 25.0 220 0.0110 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" Runoff Subcatchment B: = 5.53 cfs @ 12.40 hrs, Volume= 0.684 af, Depth> 2.89" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.20" Area (ac) 1.170 1.674 2.844 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 38.0 250 0.0050 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 3.0 50 0.1100 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 2.9 350 0.0100 2.0 Shallow Concentrated Flow, Paved Kv= 20.3 fps 43.9 650 Total Runoff Subcatchment C: = 0.64 cfs @ 11.94 hrs, Volume= 0.029 af, Depth> 3.21" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.20" Area (ac) 0.032 0.078 0.110 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 91 Weighted Average Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.20" Page 1 0 12/19/2005 Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsec) (cfs) 2.6 25 0.0400 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.9 80 0.0290 1.4 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 3.5 105 Total Subcatchment D: Runoff = 0.90 cfs @ 11.98 hrs, Volume= 0.043 af, Depth> 2.54" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.20" Area (ac) 0.115 0.089 0.204 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 84 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsee) (cfs) 6.2 85 0.0530 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.3 25 0.0600 1.5 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 6.5 110 Total Runoff Subcatchment E: = 0.13 cfs @ 11.90 hrs, Volume= 0.006 af, Depth> 3.96" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.20" Area (ac) 0.019 Runoff = CN Description 98 Impervious Subcatchment F: 1.08 cfs @ 11.97 hrs, Volume= 0.051 af, Depth> 2.29" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.20" Area (ac) 0.192 0.073 0.265 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 81 Weighted Average Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.20" Page 11 12/19/2005 Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 4.6 70 0.0780 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 1.3 110 0.0230 1.4 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 5.9 180 Total Subcatchment G: Runoff = 6.23 cfs @ 12.02 hrs, Volume= 0.343 af, Depth> 2.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.20" Area (ac) 1.064 0.613 1.677 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 83 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 1.1 60 0.0100 0.9 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 5.8 48 0.0200 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 3.1 64 0.1700 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.4 25 0.0200 1.0 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 10.4 197 Total Inflow Area = Inflow = Outflow = Discarded = Primary = Pond 1: 4" DT 0.286 ac, Inflow Depth> 1.73" 0.48 cfs @ 12.19 hrs, Volume= 0.48 cfs @ 12.19 hrs, Volume= 0.24 cfs @ 12.19 hrs, Volume= 0.24 cfs @ 12.19 hrs, Volume= for 10-yr event 0.041 af 0.041 af, Atten= 0%, Lag= 0.0 min 0.005 af 0.036 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 56.78' @ 12.19 hrs Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= (not calculated: outflow precedes inflow) Device #1 #2 Routing Primary Invert Outlet Devices 55.67' 4.0" x 425.0'long Culvert CPP, projecting, no headwall, Ke= 0.900 Outlet Invert= 40.13' S= 0.0366 'f Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior 56.77' 50.0' long x 20.0' breadth Broad-Crested Rectangular Weir Discarded Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.20" Page 12 12/19/2005 Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coet. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Discarded OutFlow Max=0.23 cfs @ 12.19 hrs HW=56.78' (Free Discharge) L2=Broad-Crested Rectangular Weir (Weir Controls 0.23 cfs @ 0.3 fps) Primary OutFlow Max=0.24 cfs @ 12.19 hrs HW=56.78' (Free Discharge) L1=Culvert (Barrel Controls 0.24 cfs @ 2.8 fps) Inflow Area = Inflow = Outflow = Primary = Pond 2: 12" RCP 3.130 ac, Inflow Depth> 2.76" 5.77 cfs @ 12.40 hrs, Volume= 5.77 cts @ 12.40 hrs, Volume= 5.77 cfs @ 12.40 hrs, Volume= for 10-yr event 0.720 at 0.720 at, Atten= 0%, Lag= 0.0 min 0.720 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 42.96' @ 12.40 hrs Flood Elev= 48.63' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-ot-Mass del. time= (not calculated: outflow precedes inflow) Device #1 Routing Primary Invert Outlet Devices 40.13' 12.0" x 59.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 39.35' S= 0.0132 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=5.77 cfs @ 12.40 hrs HW=42.96' (Free Discharge) L1=Culvert (Inlet Controls 5.77 cfs @ 7.3 fps) Inflow Area = Inflow = Outflow = Primary = Pond 3: 12" RCP 3.240 ac, Inflow Depth> 2.78" 5.82 cfs @ 12.40 hrs, Volume= 5.82 cfs @ 12.40 hrs, Volume= 5.82 cfs @ 12.40 hrs, Volume= for 10-yr event 0.749 af 0.749 af, Atten= 0%, Lag= 0.0 min 0.749 at Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 42.76' @ 12.40 hrs Flood Elev= 48.65' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass del. time= 0.0 min ( 830.3 - 830.3 ) Invert Outlet Devices 39.35' 12.0" x 100.0'long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 38.20' S= 0.0115 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=5.82 cfs @ 12.40 hrs HW=42.76' (Free Discharge) L1=Culvert (Barrel Controls 5.82 cfs @ 7.4 fps) Device Routing #1 Primary Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@7.10 sin 001935 @2005 HydroCAD Software Solutions LLC Type 1/ 24-hr 10-yr Rainfal/=4.20" Page 13 12/19/2005 Inflow Area = Inflow = Outflow = Primary = Pond 4: 12" 3.444 ac, Inflow Depth> 2.76" 5.92 cfs @ 12.39 hrs, Volume= 5.92 cfs @ 12.39 hrs, Volume= 5.92 cfs @ 12.39 hrs, Volume= for 10-yr event 0.793 af 0.793 af, Atten= 0%, Lag= 0.0 min 0.793 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 42.97' @ 12.39 hrs Flood Elev= 44.42' Plug-Flow detention time= 0.0 min calculated for 0.793 af (100% of inflow) Center-of-Mass det. time= 0.0 min (829.5 - 829.5) Device Routing #1 Primary #2 Primary Invert Outlet Devices 38.20' 12.0" x 108.0' long Culvert Rep, square edge headwall, Ke= 0.500 Outlet Invert= 38.10' S= 0.0009 'f Cc= 0.900 n= 0.012 Concrete pipe, finished 44.42' 20.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=5.92 cfs @ 12.39 hrs HW=42.97' (Free Discharge) t1=culvert (Barrel Controls 5.92 cfs @ 7.5 fps) 2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) Inflow Area = Inflow = Outflow = Primary = Pond 5: 12" 0.019 ac, Inflow Depth> 3.96" 0.13 cfs @ 11.90 hrs, Volume= 0.13 cfs @ 11.90 hrs, Volume= 0.13cfs@ 11.90hrs, Volume= for 1 O-yr event 0.006 af 0.006 af, Atten= 0%, Lag= 0.0 min 0.006 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 37.97' @ 11.90 hrs Flood Elev= 41.21' Plug-Flow detention time= 0.0 min calculated for 0.006 af (100% of inflow) Center-of-Mass det. time= (not calculated: outflow precedes inflow) Device Routing #1 Primary Invert Outlet Devices 37.75' 12.0" x 56.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 37.55' S= 0.0036 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=0.13 cfs @ 11.90 hrs HW=37.97' (Free Discharge) t.....1=Culvert (Barrel Controls 0.13 cfs @ 1.6 fps) Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.20" Page 14 12/19/2005 Inflow Area = Inflow = Outflow = Primary = Pond 6: 18" PVC 3.728 ac, Inflow Depth> 2.73" 6.04 cfs @ 12.39 hrs, Volume= 6.04 cfs @ 12.39 hrs, Volume= 6.04 cfs @ 12.39 hrs, Volume= for 10-yr event 0.849 af 0.849 af, Atten= 0%, Lag= 0.0 min 0.849 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 39.01' @ 12.39 hrs Flood Elev= 42.46' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 0.0 min (828.4 - 828.4 ) Device #1 Routing Primary Invert Outlet Devices 37.55' 18.0" x 72.0' long Culvert CPP, square edge headwall, Ke= 0.500 Outlet Invert= 37.29' S= 0.0036 'f Cc= 0.900 n= 0.010 PVC, smooth interior Primary OutFlow Max=6.04 cfs @ 12.39 hrs HW=39.01' (Free Discharge) L1=Culvert (Barrel Controls 6.04 cfs @ 4.4 fps) Inflow Area = Inflow = Outflow = Primary = Pond 7: Filtration Basin 5.405 ac, Inflow Depth> 2.65" 10.40 cfs @ 12.01 hrs, Volume= 3.61 cfs @ 12.83 hrs, Volume= 3.61 cfs @ 12.83 hrs, Volume= for 10-yr event 1.192 af 1.034 af, Atten= 65%, Lag= 49.0 min 1.034 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 37.94' @ 12.83 hrs Surf.Area= 9,456 sf Storage= 21,365 cf Plug-Flow detention time= 170.9 min calculated for 1.033 af (87% of inflow) Center-of-Mass det. time= 110.1 min ( 936.1 - 826.0 ) Volume #1 Elevation (feet) 35.00 36.00 37.00 38.00 39.00 40.00 41.00 Device Routing #1 Primary #2 Device 1 Invert 35.00' Avail.Storage Storage Description 58,556 cf Custom Stage Data (Pyramidal) Listed below (Recalc) Surf.Area (sq-ft) 5,350 6,500 8,000 9,550 11,200 13.150 15,100 Inc. Store (cubic-feet) o 5,916 7,237 8,764 10,364 12,162 14,114 Cum. Store (cubic-feet) o 5.916 13,153 21,916 32,280 44.442 58.556 Wet.Area (sq-ft) 5,350 6,540 8,078 9,673 11,373 13,372 15,379 Invert Outlet Devices 33.00' 8.0" x 80.0' long Culvert CPP, square edge headwall, Ke= 0.500 Outlet Invert= 23.00' S= 0.1250 'f Cc= 0.900 n= 0.010 PVC. smooth interior 34.00' 4.0" x 88.0' long Culvert X 3.00 Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.20" Page 15 12/19/2005 #3 Device 2 CPP, projecting, no headwall, Ke= 0.900 Outlet Invert= 33.00' S= 0.0114 'f Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior 35.00' 12.000 inlhr Exfiltration over Surface area above invert Excluded Surface area = 5,350 sf 37.00' 24.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 Primary OutFlow Max=3.61 cfs @ 12.83 hrs HW=37.94' (Free Discharge) L1=Culvert (Inlet Controls 3.61 cfs @ 10.3 fps) t2=culvert (Passes < 0.82 cfs potential flow) L3=Exfiltration (Passes < 1.14 cfs potential flow) 4=Orifice/Grate (Passes < 4.81 cfs potential flow) Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAO@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 100-yr Rainfal/=6.00" Page 16 12/19/2005 Runoff Subcatchment A: = 0.89 cfs @ 12.19 hrs, Volume= 0.075 af, Depth> 3.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=6.00" Area (ac) 0.286 CN Description 74 >75% Grass cover, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 25.0 220 0.0110 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" Runoff Subcatchment B: = 8.67 cfs @ 12.39 hrs, Volume= 1.086 af, Depth> 4.58" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=6.00" Area (ac) 1.170 1.674 2.844 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 38.0 250 0.0050 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 3.0 50 0.1100 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 2.9 350 0.0100 2.0 Shallow Concentrated Flow, Paved Kv= 20.3 fps 43.9 650 Total Runoff Subcatchment c: = 0.96 cfs @ 11.94 hrs, Volume= 0.045 af, Depth> 4.95" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=6.00" Area (ac) 0.032 0.078 0.110 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 91 Weighted Average Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 100-yr Rainfal/=6.00" Page 17 12/19/2005 Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 2.6 25 0.0400 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.9 80 0.0290 1.4 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 3.5 105 Total Subcatchment D: Runoff 1.44 cfs @ 11.98 hrs, Volume= 0.071 af, Depth> 4.19" = Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=6.00" Area (ac) 0.115 0.089 0.204 CN Description 74 > 75% Grass cover, Good, HSG C 98 Impervious 84 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) ( ftIft) (ftIsec) (cfs) 6.2 85 0.0530 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.3 25 0.0600 1.5 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 6.5 110 Total Subcatchment E: Runoff 0.19 cfs @ 11.90 hrs, Volume= 0.009 af, Depth> 5.76" = Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=6.00" Area (ac) 0.019 CN Description 98 Impervious Subcatchment F: Runoff = 1.80 cfs @ 11.97 hrs, Volume= 0.086 af, Depth> 3.88" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=6.00" Area (ac) 0.192 0.073 0.265 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 81 Weighted Average Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@7.10 sIn 001935 @2005 HydroCAD Software Solutions LLC Type 1/24-hr 100-yr Rainfall=6.00" Page 18 12/19/2005 Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 4.6 70 0.0780 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 1.3 110 0.0230 1.4 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 5.9 180 Total Subcatchment G: Runoff = 10.17 cfs @ 12.02 hrs, Volume= 0.570 af, Depth> 4.08" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfal.I=6.00" Area (ac) 1.064 0.613 1.677 CN Description 74 >75% Grass cover, Good, HSG C 98 Impervious 83 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 1.1 60 0.0100 0.9 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.80" 5.8 48 0.0200 0.1 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 3.1 64 0.1700 0.3 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 0.4 25 0.0200 1.0 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 10.4 197 Total Inflow Area = Inflow = Outflow = Discarded = Primary = Pond 1: 4" DT 0.286 ac, Inflow Depth> 3.16" 0.89 cfs @ 12.19 hrs, Volume= 0.89 cfs @ 12.19 hrs, Volume= 0.65 cfs @ 12.19 hrs, Volume= 0.24 cfs @ 12.19 hrs, Volume= for 100-yr event 0.075 af 0.075 af, Atten= 0%, Lag= 0.0 min 0.020 af 0.056 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 56.80' @ 12.19 hrs Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 0.0 min (839.2 - 839.2) Device #1 Routing Primary #2 Discarded Invert Outlet Devices 55.67' 4.0" x 425.0'long Culvert CPP, projecting, no headwall, Ke= 0.900 Outlet Invert= 40.13' S= 0.0366 'f Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior 56.77' 50.0' long x 20.0' breadth Broad-Crested Rectangular Weir Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 100-yr Rainfal/=6.00" Page 19 12/19/2005 Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Discarded OutFlow Max=0.64 cfs @ 12.19 hrs HW=56.80' (Free Discharge) L2=Broad-Crested Rectangular Weir (Weir Controls 0.64 cfs @ 0.5 fps) Primary OutFlow Max=0.24 cfs @ 12.19 hrs HW=56.80' (Free Discharge) L1=Culvert (Barrel Controls 0.24 cfs @ 2.8 fps) Inflow Area = Inflow = Outflow = Primary = Pond 2: 12" RCP 3.130 ac, Inflow Depth> 4.38" 8.91 cfs @ 12.39 hrs, Volume= 8.91 cfs @ 12.39 hrs, Volume= 8.91 cfs @ 12.39 hrs, Volume= for 1 OO-yr event 1.142 af 1.142 af, Atten= 0%, Lag= 0.0 min 1.142 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 46.50' @ 12.39 hrs Flood Elev= 48.63' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass del. time= (not calculated: outflow precedes inflow) Device Routing #1 Primary Invert Outlet Devices 40.13' 12.0" x 59.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 39.35' S= 0.0132 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=8.90 cfs @ 12.39 hrs HW=46.49' (Free Discharge) L1=Culvert (Barrel Controls 8.90 cfs @ 11.3 fps) Inflow Area = Inflow = Outflow = Primary = Pond 3: 12" RCP 3.240 ac, Inflow Depth> 4.40" 8.99 cfs @ 12.39 hrs, Volume= 8.99 cfs @ 12.39 hrs, Volume= 8.99 cfs @ 12.39 hrs, Volume= for 1 OO-yr event 1.187 af 1.187 af, Atten= 0%, Lag= 0.0 min 1.187 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 47.69' @ 12.39 hrs Flood Elev= 48.65' Plug-Flow detention time= 0.0 min calculated for 1.187 af (100% of inflow) Center-of-Mass del. time= (not calculated: outflow precedes inflow) Device Routing #1 Primary Invert Outlet Devices 39.35' 12.0" x 100.0'long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 38.20' S= 0.0115 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max=8.98 cfs @ 12.39 hrs HW=47.68' (Free Discharge) L1 =Culvert (Barrel Controls 8.98 cfs @ 11.4 fps) Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sin 001935 @2005 HydroCAD Software Solutions LLC Type 1/24-hr 100-yr Rainfal/=6.00" Page 20 12/19/2005 Inflow Area = Inflow = Outflow = Primary = Pond 4: 12" 3.444 ac, Inflow Depth> 4.38" 9.13 cfs @ 12.39 hrs, Volume= 9.13 efs @ 12.39 hrs, Volume= 9.13 cfs @ 12.39 hrs, Volume= for 100-yr event 1.258 af 1.258 af, Atten= 0%, Lag= 0.0 min 1.258 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 44.55' @ 12.39 hrs Flood Elev= 44.42' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= (not calculated: outflow precedes inflow) Device #1 Routing Primary #2 Primary Invert Outlet Devices 38.20' 12.0" x 108.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 38.10' S= 0.0009 'f Cc= 0.900 n= 0.012 Concrete pipe, finished 44.42' 20.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=9.13 cfs @ 12.39 hrs HW=44.55' (Free Discharge) t1=Culvert (Barrel Controls 7.02 cfs @ 8.9 fps) 2=Broad-Crested Rectangular Weir (Weir Controls 2.10 cfs @ 0.8 fps) Inflow Area = Inflow = Outflow = Primary = Pond 5: 12" 0.019 ac, Inflow Depth> 5.76" 0.19 cfs @ 11.90 hrs, Volume= 0.19 cfs @ 11.90 hrs, Volume= 0.19 cfs @ 11.90 hrs, Volume= for 100-yr event 0.009 af 0.009 af, Atten= 0%, Lag= 0.0 min 0.009 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 38.01' @ 11.90 hrs Flood Elev= 41.21' Plug-Flow detention time= 0.0 min calculated for 0.009 af (100% of inflow) Center-of-Mass det. time= (not calculated: outflow precedes inflow) Device Routing #1 Primary Invert Outlet Devices 37.75' 12.0" x 56.0'long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 37.55' S= 0.0036 'f Cc= 0.900 n= 0.012 Concrete pipe, finished Primary Outflow Max=0.19 cfs @ 11.90 hrs HW=38.01' (Free Discharge) '-1=Culvert (Barrel Controls 0.19 cfs @ 1.8 fps) Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 100-yr Rainfal/=6.00" Page 21 12/19/2005 Inflow Area = Inflow = Outflow = Primary = Pond 6: 18" PVC 3.728 ac, Inflow Depth> 4.36" 9.33 cfs @ 12.39 hrs, Volume= 9.33 cfs @ 12.39 hrs, Volume= 9.33 cfs @ 12.39 hrs, Volume= for 1 OO-yr event 1.353 af 1.353 af, Atten= 0%, Lag= 0.0 min 1.353 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 39.78' @ 12.39 hrs Flood Elev= 42.46' Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass del. time= (not calculated: outflow precedes inflow) Device #1 Routing Primary Invert Outlet Devices 37.55' 18.0" x 72.0'long Culvert CPP, square edge headwall, Ke= 0.500 Outlet Invert= 37.29' S= 0.0036 'f Cc= 0.900 n= 0.010 PVC, smooth interior Primary OutFlow Max=9.33 cfs @ 12.39 hrs HW=39.78' (Free Discharge) L1=Culvert (Barrel Controls 9.33 cfs @ 5.3 fps) Inflow Area = Inflow = Outflow = Primary = Pond 7: Filtration Basin 5.405 ac, Inflow Depth> 4.27" 16.80 cfs @ 12.01 hrs, Volume= 4.13cfs@ 13.00hrs, Volume= 4.13 cfs @ 13.00 hrs, Volume= for 100-yr event 1.924 af 1.714 af, Atten= 75%, Lag= 59.6 min 1.714 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 39.36' @ 13.00 hrs Surf.Area= 11,886 sf Storage= 36,448 cf Plug-Flow detention time= 153.3 min calculated for 1.714 af (89% of inflow) Center-of-Mass del. time= 100.8 min ( 913.9 - 813.1 ) Volume #1 Elevation (feet) 35.00 36.00 37.00 38.00 39.00 40.00 41.00 Device #1 Routing Primary #2 Device 1 Invert 35.00' Avail.Storage Storage Description 58,556 cf Custom Stage Data (Pyramidal) Listed below (Recalc) Surf.Area (sq-ft) 5,350 6,500 8,000 9,550 11,200 13,150 15,100 Inc. Store (cubic-feet) o 5,916 7,237 8,764 10,364 12.162 14,114 Cum. Store ( cubic-feet) o 5,916 13,153 21,916 32,280 44,442 58,556 Wet.Area (sq-ft) 5,350 6,540 8,078 9,673 11,373 13.372 15,379 Invert Outlet Devices 33.00' 8.0" x 80.0' long Culvert CPP, square edge headwall, Ke= 0.500 Outlet Invert= 23.00' S= 0.1250 'f Cc= 0.900 n= 0.010 PVC, smooth interior 34.00' 4.0" x 88.0' long Culvert X 3.00 Runoff Calculations - Filtration Prepared by Larson Engineering HydroCAD@ 7.10 sIn 001935 @ 2005 HydroCAD Software Solutions LLC Type II 24-hr 100-yr Rainfal/=6.00" Page 22 12/19/2005 #3 Device 2 CPP, projecting, no headwall, Ke= 0.900 Outlet Invert= 33.00' S= 0.0114 'f Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior 35.00' 12.000 inlhr Exfiltration over Surface area above invert Excluded Surface area = 5,350 sf 37.00' 24.0" Vert. Orifice/Grate C= 0.600 #4 Device 1 Primary OutFlow Max=4.13 cfs @ 13.00 hrs HW=39.36' (Free Discharge) L1=Culvert (Inlet Controls 4.13 cfs @ 11.8 fps) t2=culvert (Passes < 0.94 cfs potential flow) L3=Exfiltration (Passes < 1.82 cfs potential flow) 4=Orifice/Grate (Passes < 17.65 cfs potential flow) :r -z- ._~------.- :8:: "'~ g. ~~ :8;, o G f 1 i , I i i I ! I ! I I i I i i ! i 1,1 I El m Larson ~ Engineering 01 Mlnnelolll --. ... WNlIoe-Lab.MNS"1t CPlllnMul>>IFI.'....'.mm lf3mffi 2005 DRAINAGE IMPROVEMENTS MINNETONKA MIDDLE SCHOOL WEST INDEPENDENT SCHOOL DISTRICT 11278 ~1HAZEL~NEBOULEVARD EXCELSIOR, MINNESOTA 55331 EEJ DRAINAGE AREA MAP IHERa'l'CDmFf1*TTWlI"-AN,PECA:ATlCH OARtPORTWASI'IlEPARmEl'tMiORUNDERIM DlAECTIUPERVl!olONAHDnkTINAADULT u:ENIED PROl'DlllClHALlNOHtEA UNOER ntE l.AW8gf'nEITAn:ClF~A. -...-...'''' ~--JIEQ,~