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2024-08-23 Stormwater MemoMEMORANDUM Date:August 23, 2024 Re:Westwood Community Church-Hope House Expansion Stormwater Memo File0032076.0 To: City ofChanhassan;MinnehahaCreek Watershed Cc:Jim Theis,WestwoodChurch From:Chad Johnson This memo for the Stormwater Report for Hope House Expansion in Chanhassan, Minnesota provides the stormwater management design. The Hope House expansion has a total impervious of 0.54 acres. The overall project drainage is 1.68 acres. In the existing condition, the project drains in three directions. 0.67 acres (1EX) will drain to the northwest to an existing wetland complex offsite. 0.60 acres (2EX) will drain offsite to the northeast to an existing wetland. The remaining 0.48 acres (3EX) will drain to the south the th West 78 Street. The site consists of 0.30 acres of existing impervious. The proposed condition maintains the existing drainage patterns. 0.16 acres (1PD) of direct drainage will be routed to Filtration Basin 1 then discharge offsite with an additional 0.57 acres (1E) to the northwest to an existing wetland complex offsite. 0.32 acres will be routed to Filtration Basin 2 then discharge with an additional 0.37 acres (2E) and drain offsite to the th northeast. The remaining 0.25 acres (3E) will drain to the south the West 78 Street. The site consists of 0.54 acres of impervious. An existing and proposed drainage map has been attached. TBPLS Firm No. 10074302 August 23, 2024 Page 2 For Minnehaha Creek Watershed. The proposed site is 1.68 acres, and has 0.54 acres of impervious. The size is greater then 1 acre, impervious is less than 1 acre, amd the impervious changes from 0.30 to 0.54 acres (80%) is greater than 50% increase. The site requires volume control for entire site of 0.54 impervious and rate control. The tables below summarize the proposed rate control for the 1, 10 and 100 yr, 24 hour events and volume control please refer to the enclosed HyrdoCAD output for more information. Table 1a: Peak Discharge Rate-100 Year Event LocationExisting (cfs)Proposed (cfs) To Northwest5.8 4.7 To Northeast4.8 3.0 th To West 78 Street3.8 2.2 Table 1b: Peak Discharge Rate-10 Year Event LocationExisting (cfs)Proposed (cfs) To Northwest2.4 2.3 To Northeast2.3 1.5 th To West 78 Street1.9 1.1 Table 1c: Peak Discharge Rate-2 Year Event BasinExisting (cfs)Proposed (cfs) To Northwest1.0 1.0 To Northeast1.0 0.6 th To West 78 Street0.8 0.5 August 23, 2024 Page 3 Table 2: Proposed Conditions Volume Control Volume Control Impervious Area (AC)0.54 Required Vol (1.1") (CF)2,156 Provided Vol (CF)2,895 For volume control, two proposed filtration have been proposed. The filtration basin will be 1.5 feet deep and will have 1.5 feet filter media to maintain a 0.45 in/hour for 48 hours of drawdown. The volume for Filtration Basin 1 is 1,815 cf (1006.5 to 1005.0) and 1,080 cf of volume in Filtration Basin 2 (1010.5 to 1009.0). The proposed stormwater management for the proposed expansion meet the required rate control and volume control for the site. Please contact me with any questions. PROPOSED EXISTING 3EX 2E 2EX1E 1EX Onsite Drainage to Onsite Drainage to NE Onsite Drainage to NEOnsite Existing Dainage Onsite Existing Dainage South (West 78th to NW to NW Street) 2PD 1PD Onsite Drainage to Pond 1 Filtration Basin 2P 1P Filtration Basin 2 Filtration Basin 2 3E 2R 1R Onsite Drainage to To NE South (West 78th To NW Street) Routing Diagram for Design 24-08-23 Reach Pond Subcat Link Prepared by Westwood Professional Services, Printed 8/23/2024 HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 2 Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=0.570 ac 24.56% Impervious Runoff Depth=1.11" Subcatchment 1E: Onsite Existing Dainage to Tc=10.0 min CN=84 Runoff=0.98 cfs 0.053 af Runoff Area=0.670 ac 10.45% Impervious Runoff Depth=0.94" Subcatchment 1EX: Onsite Existing Dainage to Tc=10.0 min CN=81 Runoff=0.96 cfs 0.052 af Runoff Area=0.160 ac 43.75% Impervious Runoff Depth=1.37" Subcatchment 1PD: Pond 1 Tc=10.0 min CN=88 Runoff=0.34 cfs 0.018 af Runoff Area=0.370 ac 24.32% Impervious Runoff Depth=1.11" Subcatchment 2E: Onsite Drainage to NE Tc=10.0 min CN=84 Runoff=0.64 cfs 0.034 af Runoff Area=0.600 ac 21.67% Impervious Runoff Depth=1.05" Subcatchment 2EX: Onsite Drainage to NE Tc=10.0 min CN=83 Runoff=0.98 cfs 0.052 af Runoff Area=0.320 ac 40.63% Impervious Runoff Depth=1.30" Subcatchment 2PD: Onsite Drainage to Tc=10.0 min CN=87 Runoff=0.65 cfs 0.035 af Runoff Area=0.250 ac 44.00% Impervious Runoff Depth=1.37" Subcatchment 3E: Onsite Drainage to South Tc=10.0 min CN=88 Runoff=0.53 cfs 0.029 af Runoff Area=0.480 ac 20.83% Impervious Runoff Depth=1.05" Subcatchment 3EX: Onsite Drainage to South Tc=10.0 min CN=83 Runoff=0.78 cfs 0.042 af Inflow=0.99 cfs 0.071 af Reach 1R: To NW Outflow=0.99 cfs 0.071 af Inflow=0.65 cfs 0.069 af Reach 2R: To NE Outflow=0.65 cfs 0.069 af Peak Elev=1,009.90' Storage=555 cf Inflow=0.34 cfs 0.018 af Pond 1P: Filtration Basin 2 Outflow=0.01 cfs 0.018 af Peak Elev=1,005.97' Storage=1,070 cf Inflow=0.65 cfs 0.035 af Pond 2P: Filtration Basin 2 Outflow=0.01 cfs 0.035 af Total Runoff Area = 3.420 ac Runoff Volume = 0.315 af Average Runoff Depth = 1.11" 75.44% Pervious = 2.580 ac 24.56% Impervious = 0.840 ac 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 1E: Onsite Existing Dainage to NW Runoff=0.98 cfs @ 12.18 hrs, Volume=0.053 af, Depth=1.11" Routed to Reach 1R : To NW Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.09079Woods/grass comb., Good, HSG D 0.14098Paved roads w/curbs & sewers, HSG D 0.34080>75% Grass cover, Good, HSG D 0.57084Weighted Average 0.43075.44% Pervious Area 0.14024.56% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1E: Onsite Existing Dainage to NW Hydrograph Runoff 0.98 cfs 1 MSE 24-hr 3 1-yr Rainfall=2.49" Runoff Area=0.570 ac Runoff Volume=0.053 af ) s f c Runoff Depth=1.11" ( w o l Tc=10.0 min F CN=84 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 1EX: Onsite Existing Dainage to NW Runoff=0.96 cfs @ 12.18 hrs, Volume=0.052 af, Depth=0.94" Routed to nonexistent node 1EXP Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.60079Woods/grass comb., Good, HSG D 0.07098Paved roads w/curbs & sewers, HSG D 0.67081Weighted Average 0.60089.55% Pervious Area 0.07010.45% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1EX: Onsite Existing Dainage to NW Hydrograph Runoff 0.96 cfs 1 MSE 24-hr 3 1-yr Rainfall=2.49" Runoff Area=0.670 ac Runoff Volume=0.052 af ) s f c Runoff Depth=0.94" ( w o l Tc=10.0 min F CN=81 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 1PD: Pond 1 Runoff=0.34 cfs @ 12.18 hrs, Volume=0.018 af, Depth=1.37" Routed to Pond 1P : Filtration Basin 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.09080>75% Grass cover, Good, HSG D 0.07098Paved roads w/curbs & sewers, HSG D 0.16088Weighted Average 0.09056.25% Pervious Area 0.07043.75% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1PD: Pond 1 Hydrograph 0.38 Runoff 0.36 0.34 cfs 0.34 MSE 24-hr 3 0.32 0.3 1-yr Rainfall=2.49" 0.28 Runoff Area=0.160 ac 0.26 0.24 Runoff Volume=0.018 af ) 0.22 s f c Runoff Depth=1.37" ( 0.2 w 0.18 o l Tc=10.0 min F 0.16 0.14 CN=88 0.12 0.1 0.08 0.06 0.04 0.02 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 2E: Onsite Drainage to NE Runoff=0.64 cfs @ 12.18 hrs, Volume=0.034 af, Depth=1.11" Routed to Reach 2R : To NE Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.28080>75% Grass cover, Good, HSG D 0.09098Paved roads w/curbs & sewers, HSG D 0.37084Weighted Average 0.28075.68% Pervious Area 0.09024.32% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2E: Onsite Drainage to NE Hydrograph Runoff 0.7 0.64 cfs 0.65 MSE 24-hr 3 0.6 1-yr Rainfall=2.49" 0.55 0.5 Runoff Area=0.370 ac 0.45 Runoff Volume=0.034 af ) s 0.4 f c Runoff Depth=1.11" ( 0.35 w o l Tc=10.0 min F 0.3 CN=84 0.25 0.2 0.15 0.1 0.05 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment 2EX: Onsite Drainage to NE Runoff=0.98 cfs @ 12.18 hrs, Volume=0.052 af, Depth=1.05" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.47079Woods/grass comb., Good, HSG D 0.13098Paved roads w/curbs & sewers, HSG D 0.60083Weighted Average 0.47078.33% Pervious Area 0.13021.67% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2EX: Onsite Drainage to NE Hydrograph Runoff 0.98 cfs 1 MSE 24-hr 3 1-yr Rainfall=2.49" Runoff Area=0.600 ac Runoff Volume=0.052 af ) s f c Runoff Depth=1.05" ( w o l Tc=10.0 min F CN=83 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 2PD: Onsite Drainage to Filtration Basin Runoff=0.65 cfs @ 12.18 hrs, Volume=0.035 af, Depth=1.30" Routed to Pond 2P : Filtration Basin 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.19080>75% Grass cover, Good, HSG D 0.13098Paved roads w/curbs & sewers, HSG D 0.32087Weighted Average 0.19059.37% Pervious Area 0.13040.63% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2PD: Onsite Drainage to Filtration Basin Hydrograph Runoff 0.7 0.65 cfs 0.65 MSE 24-hr 3 0.6 1-yr Rainfall=2.49" 0.55 Runoff Area=0.320 ac 0.5 0.45 Runoff Volume=0.035 af ) s f 0.4 c Runoff Depth=1.30" ( w 0.35 o l Tc=10.0 min F 0.3 CN=87 0.25 0.2 0.15 0.1 0.05 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 3E: Onsite Drainage to South (West 78th Street) Runoff=0.53 cfs @ 12.18 hrs, Volume=0.029 af, Depth=1.37" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.09079Woods/grass comb., Good, HSG D 0.11098Paved roads w/curbs & sewers, HSG D 0.05080>75% Grass cover, Good, HSG D 0.25088Weighted Average 0.14056.00% Pervious Area 0.11044.00% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 3E: Onsite Drainage to South (West 78th Street) Hydrograph Runoff 0.53 cfs 0.55 MSE 24-hr 3 0.5 1-yr Rainfall=2.49" 0.45 Runoff Area=0.250 ac 0.4 Runoff Volume=0.029 af 0.35 ) s f c Runoff Depth=1.37" ( 0.3 w o l Tc=10.0 min F 0.25 CN=88 0.2 0.15 0.1 0.05 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 3EX: Onsite Drainage to South (West 78th Street) Runoff=0.78 cfs @ 12.18 hrs, Volume=0.042 af, Depth=1.05" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 1-yr Rainfall=2.49" Area (ac)CNDescription 0.38079Woods/grass comb., Good, HSG D 0.10098Paved roads w/curbs & sewers, HSG D 0.48083Weighted Average 0.38079.17% Pervious Area 0.10020.83% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 3EX: Onsite Drainage to South (West 78th Street) Hydrograph Runoff 0.85 0.78 cfs 0.8 MSE 24-hr 3 0.75 0.7 1-yr Rainfall=2.49" 0.65 Runoff Area=0.480 ac 0.6 0.55 Runoff Volume=0.042 af ) 0.5 s f c Runoff Depth=1.05" ( 0.45 w o 0.4 l Tc=10.0 min F 0.35 CN=83 0.3 0.25 0.2 0.15 0.1 0.05 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 11 Summary for Reach 1R: To NW Inflow Area =0.730 ac,28.77% Impervious, Inflow Depth = 1.17" for 1-yr event Inflow=0.99 cfs @ 12.18 hrs, Volume=0.071 af Outflow=0.99 cfs @ 12.18 hrs, Volume=0.071 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach 1R: To NW Hydrograph Inflow Outflow 0.99 cfs 0.99 cfs Inflow Area=0.730 ac 1 ) s f c ( w o l F 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 12 Summary for Reach 2R: To NE Inflow Area =0.690 ac,31.88% Impervious, Inflow Depth = 1.20" for 1-yr event Inflow=0.65 cfs @ 12.18 hrs, Volume=0.069 af Outflow=0.65 cfs @ 12.18 hrs, Volume=0.069 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach 2R: To NE Hydrograph Inflow Outflow 0.65 cfs 0.7 0.65 cfs Inflow Area=0.690 ac 0.65 0.6 0.55 0.5 0.45 ) s f 0.4 c ( 0.35 w o l F 0.3 0.25 0.2 0.15 0.1 0.05 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 13 Summary for Pond 1P: Filtration Basin 2 Inflow Area =0.160 ac,43.75% Impervious, Inflow Depth = 1.37" for 1-yr event Inflow=0.34 cfs @ 12.18 hrs, Volume=0.018 af Outflow=0.01 cfs @ 15.17 hrs, Volume=0.018 af, Atten= 98%, Lag= 179.8 min Primary=0.01 cfs @ 15.17 hrs, Volume=0.018 af Routed to Reach 1R : To NW Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 1,009.90' @ 15.17 hrs Surf.Area= 772 sf Storage= 555 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 750.5 min ( 1,556.5 - 806.0 ) VolumeInvertAvail.StorageStorage Description Custom Stage Data (Prismatic) #11,009.00'3,950 cf Listed below (Recalc) ElevationSurf.AreaInc.StoreCum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 1,009.0046000 1,010.509801,0801,080 1,012.501,8902,8703,950 DeviceRoutingInvertOutlet Devices 0.450 in/hr Exfiltration over Surface area #1Device 21,009.00' 6.0" Round 6" Draintile #2Device 31,007.50' L= 40.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,007.50' / 1,007.30' S= 0.0050 '/' Cc= 0.900 n= 0.011 PVC, smooth interior, Flow Area= 0.20 sf 12.0" Round Culvert #3Primary1,007.30' L= 150.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,007.30' / 1,006.60' S= 0.0047 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.01 cfs @ 15.17 hrs HW=1,009.90' TW=0.00' (Dynamic Tailwater) 3=Culvert (Passes 0.01 cfs of 3.84 cfs potential flow) 2=6" Draintile (Passes 0.01 cfs of 1.18 cfs potential flow) 1=Exfiltration (Exfiltration Controls 0.01 cfs) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 14 Pond 1P: Filtration Basin 2 Hydrograph Inflow 0.38 Primary 0.34 cfs 0.36 Inflow Area=0.160 ac 0.34 0.32 Peak Elev=1,009.90' 0.3 0.28 Storage=555 cf 0.26 0.24 ) 0.22 s f c ( 0.2 w 0.18 o l F 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.01 cfs 0.02 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 15 Summary for Pond 2P: Filtration Basin 2 Inflow Area =0.320 ac,40.63% Impervious, Inflow Depth = 1.30" for 1-yr event Inflow=0.65 cfs @ 12.18 hrs, Volume=0.035 af Outflow=0.01 cfs @ 15.28 hrs, Volume=0.035 af, Atten= 98%, Lag= 186.3 min Primary=0.01 cfs @ 15.28 hrs, Volume=0.035 af Routed to Reach 2R : To NE Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 1,005.97' @ 15.28 hrs Surf.Area= 1,302 sf Storage= 1,070 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 840.0 min ( 1,649.0 - 808.9 ) VolumeInvertAvail.StorageStorage Description Custom Stage Data (Prismatic) #11,005.00'5,881 cf Listed below (Recalc) ElevationSurf.AreaInc.StoreCum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 1,005.0090000 1,006.501,5201,8151,815 1,008.502,5464,0665,881 DeviceRoutingInvertOutlet Devices 0.450 in/hr Exfiltration over Surface area #1Device 21,005.00' 6.0" Round 6" Draintile #2Device 31,003.50' L= 50.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,003.50' / 1,003.25' S= 0.0050 '/' Cc= 0.900 n= 0.011 PVC, smooth interior, Flow Area= 0.20 sf 12.0" Round Culvert #3Primary1,003.25' L= 125.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,003.25' / 1,002.60' S= 0.0052 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.01 cfs @ 15.28 hrs HW=1,005.97' TW=0.00' (Dynamic Tailwater) 3=Culvert (Passes 0.01 cfs of 4.17 cfs potential flow) 2=6" Draintile (Passes 0.01 cfs of 1.13 cfs potential flow) 1=Exfiltration (Exfiltration Controls 0.01 cfs) 24-08-23 MSE 24-hr 3 1-yr Rainfall=2.49" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 16 Pond 2P: Filtration Basin 2 Hydrograph Inflow Primary 0.65 cfs 0.7 Inflow Area=0.320 ac 0.65 0.6 Peak Elev=1,005.97' 0.55 Storage=1,070 cf 0.5 0.45 ) s f 0.4 c ( w 0.35 o l F 0.3 0.25 0.2 0.15 0.1 0.05 0.01 cfs 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 17 Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=0.570 ac 24.56% Impervious Runoff Depth=2.58" Subcatchment 1E: Onsite Existing Dainage to Tc=10.0 min CN=84 Runoff=2.27 cfs 0.123 af Runoff Area=0.670 ac 10.45% Impervious Runoff Depth=2.32" Subcatchment 1EX: Onsite Existing Dainage to Tc=10.0 min CN=81 Runoff=2.42 cfs 0.130 af Runoff Area=0.160 ac 43.75% Impervious Runoff Depth=2.95" Subcatchment 1PD: Pond 1 Tc=10.0 min CN=88 Runoff=0.72 cfs 0.039 af Runoff Area=0.370 ac 24.32% Impervious Runoff Depth=2.58" Subcatchment 2E: Onsite Drainage to NE Tc=10.0 min CN=84 Runoff=1.48 cfs 0.080 af Runoff Area=0.600 ac 21.67% Impervious Runoff Depth=2.50" Subcatchment 2EX: Onsite Drainage to NE Tc=10.0 min CN=83 Runoff=2.32 cfs 0.125 af Runoff Area=0.320 ac 40.63% Impervious Runoff Depth=2.86" Subcatchment 2PD: Onsite Drainage to Tc=10.0 min CN=87 Runoff=1.40 cfs 0.076 af Runoff Area=0.250 ac 44.00% Impervious Runoff Depth=2.95" Subcatchment 3E: Onsite Drainage to South Tc=10.0 min CN=88 Runoff=1.12 cfs 0.062 af Runoff Area=0.480 ac 20.83% Impervious Runoff Depth=2.50" Subcatchment 3EX: Onsite Drainage to South Tc=10.0 min CN=83 Runoff=1.86 cfs 0.100 af Inflow=2.28 cfs 0.162 af Reach 1R: To NW Outflow=2.28 cfs 0.162 af Inflow=1.49 cfs 0.154 af Reach 2R: To NE Outflow=1.49 cfs 0.154 af Peak Elev=1,010.72' Storage=1,301 cf Inflow=0.72 cfs 0.039 af Pond 1P: Filtration Basin 2 Outflow=0.01 cfs 0.039 af Peak Elev=1,006.97' Storage=2,584 cf Inflow=1.40 cfs 0.076 af Pond 2P: Filtration Basin 2 Outflow=0.02 cfs 0.074 af Total Runoff Area = 3.420 ac Runoff Volume = 0.734 af Average Runoff Depth = 2.58" 75.44% Pervious = 2.580 ac 24.56% Impervious = 0.840 ac 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment 1E: Onsite Existing Dainage to NW Runoff=2.27 cfs @ 12.18 hrs, Volume=0.123 af, Depth=2.58" Routed to Reach 1R : To NW Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.09079Woods/grass comb., Good, HSG D 0.14098Paved roads w/curbs & sewers, HSG D 0.34080>75% Grass cover, Good, HSG D 0.57084Weighted Average 0.43075.44% Pervious Area 0.14024.56% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1E: Onsite Existing Dainage to NW Hydrograph Runoff 2.27 cfs MSE 24-hr 3 2 10-yr Rainfall=4.24" Runoff Area=0.570 ac Runoff Volume=0.123 af ) s f c Runoff Depth=2.58" ( w o l Tc=10.0 min F 1 CN=84 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment 1EX: Onsite Existing Dainage to NW Runoff=2.42 cfs @ 12.18 hrs, Volume=0.130 af, Depth=2.32" Routed to nonexistent node 1EXP Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.60079Woods/grass comb., Good, HSG D 0.07098Paved roads w/curbs & sewers, HSG D 0.67081Weighted Average 0.60089.55% Pervious Area 0.07010.45% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1EX: Onsite Existing Dainage to NW Hydrograph Runoff 2.42 cfs MSE 24-hr 3 10-yr Rainfall=4.24" 2 Runoff Area=0.670 ac Runoff Volume=0.130 af ) s f c Runoff Depth=2.32" ( w o l Tc=10.0 min F 1 CN=81 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 20 Summary for Subcatchment 1PD: Pond 1 Runoff=0.72 cfs @ 12.17 hrs, Volume=0.039 af, Depth=2.95" Routed to Pond 1P : Filtration Basin 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.09080>75% Grass cover, Good, HSG D 0.07098Paved roads w/curbs & sewers, HSG D 0.16088Weighted Average 0.09056.25% Pervious Area 0.07043.75% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1PD: Pond 1 Hydrograph 0.8 Runoff 0.72 cfs 0.75 0.7 MSE 24-hr 3 0.65 10-yr Rainfall=4.24" 0.6 Runoff Area=0.160 ac 0.55 0.5 Runoff Volume=0.039 af ) s 0.45 f c Runoff Depth=2.95" ( 0.4 w o l Tc=10.0 min 0.35 F 0.3 CN=88 0.25 0.2 0.15 0.1 0.05 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 21 Summary for Subcatchment 2E: Onsite Drainage to NE Runoff=1.48 cfs @ 12.18 hrs, Volume=0.080 af, Depth=2.58" Routed to Reach 2R : To NE Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.28080>75% Grass cover, Good, HSG D 0.09098Paved roads w/curbs & sewers, HSG D 0.37084Weighted Average 0.28075.68% Pervious Area 0.09024.32% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2E: Onsite Drainage to NE Hydrograph Runoff 1.48 cfs MSE 24-hr 3 10-yr Rainfall=4.24" Runoff Area=0.370 ac Runoff Volume=0.080 af 1 ) s f c Runoff Depth=2.58" ( w o l Tc=10.0 min F CN=84 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 22 Summary for Subcatchment 2EX: Onsite Drainage to NE Runoff=2.32 cfs @ 12.18 hrs, Volume=0.125 af, Depth=2.50" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.47079Woods/grass comb., Good, HSG D 0.13098Paved roads w/curbs & sewers, HSG D 0.60083Weighted Average 0.47078.33% Pervious Area 0.13021.67% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2EX: Onsite Drainage to NE Hydrograph Runoff 2.32 cfs MSE 24-hr 3 10-yr Rainfall=4.24" 2 Runoff Area=0.600 ac Runoff Volume=0.125 af ) s f c Runoff Depth=2.50" ( w o l Tc=10.0 min F 1 CN=83 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment 2PD: Onsite Drainage to Filtration Basin Runoff=1.40 cfs @ 12.17 hrs, Volume=0.076 af, Depth=2.86" Routed to Pond 2P : Filtration Basin 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.19080>75% Grass cover, Good, HSG D 0.13098Paved roads w/curbs & sewers, HSG D 0.32087Weighted Average 0.19059.37% Pervious Area 0.13040.63% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2PD: Onsite Drainage to Filtration Basin Hydrograph Runoff 1.40 cfs MSE 24-hr 3 10-yr Rainfall=4.24" Runoff Area=0.320 ac 1 Runoff Volume=0.076 af ) s f c Runoff Depth=2.86" ( w o l Tc=10.0 min F CN=87 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 24 Summary for Subcatchment 3E: Onsite Drainage to South (West 78th Street) Runoff=1.12 cfs @ 12.17 hrs, Volume=0.062 af, Depth=2.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.09079Woods/grass comb., Good, HSG D 0.11098Paved roads w/curbs & sewers, HSG D 0.05080>75% Grass cover, Good, HSG D 0.25088Weighted Average 0.14056.00% Pervious Area 0.11044.00% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 3E: Onsite Drainage to South (West 78th Street) Hydrograph Runoff 1.12 cfs MSE 24-hr 3 1 10-yr Rainfall=4.24" Runoff Area=0.250 ac Runoff Volume=0.062 af ) s f c Runoff Depth=2.95" ( w o l Tc=10.0 min F CN=88 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 25 Summary for Subcatchment 3EX: Onsite Drainage to South (West 78th Street) Runoff=1.86 cfs @ 12.18 hrs, Volume=0.100 af, Depth=2.50" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-yr Rainfall=4.24" Area (ac)CNDescription 0.38079Woods/grass comb., Good, HSG D 0.10098Paved roads w/curbs & sewers, HSG D 0.48083Weighted Average 0.38079.17% Pervious Area 0.10020.83% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 3EX: Onsite Drainage to South (West 78th Street) Hydrograph Runoff 2 1.86 cfs MSE 24-hr 3 10-yr Rainfall=4.24" Runoff Area=0.480 ac Runoff Volume=0.100 af ) s f c Runoff Depth=2.50" ( w 1 o l Tc=10.0 min F CN=83 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 26 Summary for Reach 1R: To NW Inflow Area =0.730 ac,28.77% Impervious, Inflow Depth = 2.66" for 10-yr event Inflow=2.28 cfs @ 12.18 hrs, Volume=0.162 af Outflow=2.28 cfs @ 12.18 hrs, Volume=0.162 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach 1R: To NW Hydrograph Inflow Outflow 2.28 cfs 2.28 cfs Inflow Area=0.730 ac 2 ) s f c ( w o l F 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 27 Summary for Reach 2R: To NE Inflow Area =0.690 ac,31.88% Impervious, Inflow Depth > 2.68" for 10-yr event Inflow=1.49 cfs @ 12.18 hrs, Volume=0.154 af Outflow=1.49 cfs @ 12.18 hrs, Volume=0.154 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach 2R: To NE Hydrograph Inflow Outflow 1.49 cfs 1.49 cfs Inflow Area=0.690 ac 1 ) s f c ( w o l F 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 28 Summary for Pond 1P: Filtration Basin 2 Inflow Area =0.160 ac,43.75% Impervious, Inflow Depth = 2.95" for 10-yr event Inflow=0.72 cfs @ 12.17 hrs, Volume=0.039 af Outflow=0.01 cfs @ 16.48 hrs, Volume=0.039 af, Atten= 98%, Lag= 258.2 min Primary=0.01 cfs @ 16.48 hrs, Volume=0.039 af Routed to Reach 1R : To NW Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 1,010.72' @ 16.48 hrs Surf.Area= 1,078 sf Storage= 1,301 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 1,291.9 min ( 2,082.6 - 790.7 ) VolumeInvertAvail.StorageStorage Description Custom Stage Data (Prismatic) #11,009.00'3,950 cf Listed below (Recalc) ElevationSurf.AreaInc.StoreCum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 1,009.0046000 1,010.509801,0801,080 1,012.501,8902,8703,950 DeviceRoutingInvertOutlet Devices 0.450 in/hr Exfiltration over Surface area #1Device 21,009.00' 6.0" Round 6" Draintile #2Device 31,007.50' L= 40.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,007.50' / 1,007.30' S= 0.0050 '/' Cc= 0.900 n= 0.011 PVC, smooth interior, Flow Area= 0.20 sf 12.0" Round Culvert #3Primary1,007.30' L= 150.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,007.30' / 1,006.60' S= 0.0047 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.01 cfs @ 16.48 hrs HW=1,010.72' TW=0.00' (Dynamic Tailwater) 3=Culvert (Passes 0.01 cfs of 4.46 cfs potential flow) 2=6" Draintile (Passes 0.01 cfs of 1.39 cfs potential flow) 1=Exfiltration (Exfiltration Controls 0.01 cfs) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 29 Pond 1P: Filtration Basin 2 Hydrograph Inflow 0.8 Primary 0.72 cfs 0.75 Inflow Area=0.160 ac 0.7 0.65 Peak Elev=1,010.72' 0.6 Storage=1,301 cf 0.55 0.5 ) s 0.45 f c ( 0.4 w o l 0.35 F 0.3 0.25 0.2 0.15 0.1 0.01 cfs 0.05 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 30 Summary for Pond 2P: Filtration Basin 2 Inflow Area =0.320 ac,40.63% Impervious, Inflow Depth = 2.86" for 10-yr event Inflow=1.40 cfs @ 12.17 hrs, Volume=0.076 af Outflow=0.02 cfs @ 18.05 hrs, Volume=0.074 af, Atten= 99%, Lag= 352.7 min Primary=0.02 cfs @ 18.05 hrs, Volume=0.074 af Routed to Reach 2R : To NE Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 1,006.97' @ 18.05 hrs Surf.Area= 1,761 sf Storage= 2,584 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 1,478.6 min ( 2,271.7 - 793.2 ) VolumeInvertAvail.StorageStorage Description Custom Stage Data (Prismatic) #11,005.00'5,881 cf Listed below (Recalc) ElevationSurf.AreaInc.StoreCum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 1,005.0090000 1,006.501,5201,8151,815 1,008.502,5464,0665,881 DeviceRoutingInvertOutlet Devices 0.450 in/hr Exfiltration over Surface area #1Device 21,005.00' 6.0" Round 6" Draintile #2Device 31,003.50' L= 50.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,003.50' / 1,003.25' S= 0.0050 '/' Cc= 0.900 n= 0.011 PVC, smooth interior, Flow Area= 0.20 sf 12.0" Round Culvert #3Primary1,003.25' L= 125.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,003.25' / 1,002.60' S= 0.0052 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.02 cfs @ 18.05 hrs HW=1,006.97' TW=0.00' (Dynamic Tailwater) 3=Culvert (Passes 0.02 cfs of 4.97 cfs potential flow) 2=6" Draintile (Passes 0.02 cfs of 1.36 cfs potential flow) 1=Exfiltration (Exfiltration Controls 0.02 cfs) 24-08-23 MSE 24-hr 3 10-yr Rainfall=4.24" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 31 Pond 2P: Filtration Basin 2 Hydrograph Inflow Primary 1.40 cfs Inflow Area=0.320 ac Peak Elev=1,006.97' Storage=2,584 cf 1 ) s f c ( w o l F 0.02 cfs 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 32 Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=0.570 ac 24.56% Impervious Runoff Depth=5.44" Subcatchment 1E: Onsite Existing Dainage to Tc=10.0 min CN=84 Runoff=4.64 cfs 0.259 af Runoff Area=0.670 ac 10.45% Impervious Runoff Depth=5.10" Subcatchment 1EX: Onsite Existing Dainage to Tc=10.0 min CN=81 Runoff=5.19 cfs 0.285 af Runoff Area=0.160 ac 43.75% Impervious Runoff Depth=5.90" Subcatchment 1PD: Pond 1 Tc=10.0 min CN=88 Runoff=1.38 cfs 0.079 af Runoff Area=0.370 ac 24.32% Impervious Runoff Depth=5.44" Subcatchment 2E: Onsite Drainage to NE Tc=10.0 min CN=84 Runoff=3.01 cfs 0.168 af Runoff Area=0.600 ac 21.67% Impervious Runoff Depth=5.33" Subcatchment 2EX: Onsite Drainage to NE Tc=10.0 min CN=83 Runoff=4.81 cfs 0.267 af Runoff Area=0.320 ac 40.63% Impervious Runoff Depth=5.79" Subcatchment 2PD: Onsite Drainage to Tc=10.0 min CN=87 Runoff=2.72 cfs 0.154 af Runoff Area=0.250 ac 44.00% Impervious Runoff Depth=5.90" Subcatchment 3E: Onsite Drainage to South Tc=10.0 min CN=88 Runoff=2.16 cfs 0.123 af Runoff Area=0.480 ac 20.83% Impervious Runoff Depth=5.33" Subcatchment 3EX: Onsite Drainage to South Tc=10.0 min CN=83 Runoff=3.85 cfs 0.213 af Inflow=4.66 cfs 0.324 af Reach 1R: To NW Outflow=4.66 cfs 0.324 af Inflow=3.03 cfs 0.280 af Reach 2R: To NE Outflow=3.03 cfs 0.280 af Peak Elev=1,011.81' Storage=2,757 cf Inflow=1.38 cfs 0.079 af Pond 1P: Filtration Basin 2 Outflow=0.02 cfs 0.066 af Peak Elev=1,008.38' Storage=5,575 cf Inflow=2.72 cfs 0.154 af Pond 2P: Filtration Basin 2 Outflow=0.03 cfs 0.112 af Total Runoff Area = 3.420 ac Runoff Volume = 1.547 af Average Runoff Depth = 5.43" 75.44% Pervious = 2.580 ac 24.56% Impervious = 0.840 ac 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 33 Summary for Subcatchment 1E: Onsite Existing Dainage to NW Runoff=4.64 cfs @ 12.17 hrs, Volume=0.259 af, Depth=5.44" Routed to Reach 1R : To NW Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.09079Woods/grass comb., Good, HSG D 0.14098Paved roads w/curbs & sewers, HSG D 0.34080>75% Grass cover, Good, HSG D 0.57084Weighted Average 0.43075.44% Pervious Area 0.14024.56% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1E: Onsite Existing Dainage to NW Hydrograph Runoff 5 4.64 cfs MSE 24-hr 3 100-yr Rainfall=7.32" 4 Runoff Area=0.570 ac Runoff Volume=0.259 af ) 3 s f c Runoff Depth=5.44" ( w o l Tc=10.0 min F 2 CN=84 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 34 Summary for Subcatchment 1EX: Onsite Existing Dainage to NW Runoff=5.19 cfs @ 12.17 hrs, Volume=0.285 af, Depth=5.10" Routed to nonexistent node 1EXP Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.60079Woods/grass comb., Good, HSG D 0.07098Paved roads w/curbs & sewers, HSG D 0.67081Weighted Average 0.60089.55% Pervious Area 0.07010.45% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1EX: Onsite Existing Dainage to NW Hydrograph Runoff 5.19 cfs MSE 24-hr 3 5 100-yr Rainfall=7.32" Runoff Area=0.670 ac 4 Runoff Volume=0.285 af ) s f c Runoff Depth=5.10" ( 3 w o l Tc=10.0 min F CN=81 2 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 35 Summary for Subcatchment 1PD: Pond 1 Runoff=1.38 cfs @ 12.17 hrs, Volume=0.079 af, Depth=5.90" Routed to Pond 1P : Filtration Basin 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.09080>75% Grass cover, Good, HSG D 0.07098Paved roads w/curbs & sewers, HSG D 0.16088Weighted Average 0.09056.25% Pervious Area 0.07043.75% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 1PD: Pond 1 Hydrograph Runoff 1.38 cfs MSE 24-hr 3 100-yr Rainfall=7.32" Runoff Area=0.160 ac 1 Runoff Volume=0.079 af ) s f c Runoff Depth=5.90" ( w o l Tc=10.0 min F CN=88 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 36 Summary for Subcatchment 2E: Onsite Drainage to NE Runoff=3.01 cfs @ 12.17 hrs, Volume=0.168 af, Depth=5.44" Routed to Reach 2R : To NE Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.28080>75% Grass cover, Good, HSG D 0.09098Paved roads w/curbs & sewers, HSG D 0.37084Weighted Average 0.28075.68% Pervious Area 0.09024.32% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2E: Onsite Drainage to NE Hydrograph Runoff 3.01 cfs 3 MSE 24-hr 3 100-yr Rainfall=7.32" Runoff Area=0.370 ac Runoff Volume=0.168 af 2 ) s f c Runoff Depth=5.44" ( w o l Tc=10.0 min F CN=84 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 37 Summary for Subcatchment 2EX: Onsite Drainage to NE Runoff=4.81 cfs @ 12.17 hrs, Volume=0.267 af, Depth=5.33" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.47079Woods/grass comb., Good, HSG D 0.13098Paved roads w/curbs & sewers, HSG D 0.60083Weighted Average 0.47078.33% Pervious Area 0.13021.67% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2EX: Onsite Drainage to NE Hydrograph Runoff 4.81 cfs 5 MSE 24-hr 3 100-yr Rainfall=7.32" 4 Runoff Area=0.600 ac Runoff Volume=0.267 af ) s 3 f c Runoff Depth=5.33" ( w o l Tc=10.0 min F 2 CN=83 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 38 Summary for Subcatchment 2PD: Onsite Drainage to Filtration Basin Runoff=2.72 cfs @ 12.17 hrs, Volume=0.154 af, Depth=5.79" Routed to Pond 2P : Filtration Basin 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.19080>75% Grass cover, Good, HSG D 0.13098Paved roads w/curbs & sewers, HSG D 0.32087Weighted Average 0.19059.37% Pervious Area 0.13040.63% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 2PD: Onsite Drainage to Filtration Basin Hydrograph 3Runoff 2.72 cfs MSE 24-hr 3 100-yr Rainfall=7.32" Runoff Area=0.320 ac 2 Runoff Volume=0.154 af ) s f c Runoff Depth=5.79" ( w o l Tc=10.0 min F CN=87 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 39 Summary for Subcatchment 3E: Onsite Drainage to South (West 78th Street) Runoff=2.16 cfs @ 12.17 hrs, Volume=0.123 af, Depth=5.90" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.09079Woods/grass comb., Good, HSG D 0.11098Paved roads w/curbs & sewers, HSG D 0.05080>75% Grass cover, Good, HSG D 0.25088Weighted Average 0.14056.00% Pervious Area 0.11044.00% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 3E: Onsite Drainage to South (West 78th Street) Hydrograph Runoff 2.16 cfs MSE 24-hr 3 2 100-yr Rainfall=7.32" Runoff Area=0.250 ac Runoff Volume=0.123 af ) s f c Runoff Depth=5.90" ( w o l Tc=10.0 min F 1 CN=88 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 40 Summary for Subcatchment 3EX: Onsite Drainage to South (West 78th Street) Runoff=3.85 cfs @ 12.17 hrs, Volume=0.213 af, Depth=5.33" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-yr Rainfall=7.32" Area (ac)CNDescription 0.38079Woods/grass comb., Good, HSG D 0.10098Paved roads w/curbs & sewers, HSG D 0.48083Weighted Average 0.38079.17% Pervious Area 0.10020.83% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) Direct Entry, 10.0 Subcatchment 3EX: Onsite Drainage to South (West 78th Street) Hydrograph Runoff 3.85 cfs 4 MSE 24-hr 3 100-yr Rainfall=7.32" 3 Runoff Area=0.480 ac Runoff Volume=0.213 af ) s f c Runoff Depth=5.33" ( w o2 l Tc=10.0 min F CN=83 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 41 Summary for Reach 1R: To NW Inflow Area =0.730 ac,28.77% Impervious, Inflow Depth > 5.33" for 100-yr event Inflow=4.66 cfs @ 12.17 hrs, Volume=0.324 af Outflow=4.66 cfs @ 12.17 hrs, Volume=0.324 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach 1R: To NW Hydrograph Inflow Outflow 4.66 cfs 5 4.66 cfs Inflow Area=0.730 ac 4 ) 3 s f c ( w o l F 2 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 42 Summary for Reach 2R: To NE Inflow Area =0.690 ac,31.88% Impervious, Inflow Depth > 4.87" for 100-yr event Inflow=3.03 cfs @ 12.17 hrs, Volume=0.280 af Outflow=3.03 cfs @ 12.17 hrs, Volume=0.280 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach 2R: To NE Hydrograph Inflow Outflow 3.03 cfs 3.03 cfs Inflow Area=0.690 ac 3 2 ) s f c ( w o l F 1 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 43 Summary for Pond 1P: Filtration Basin 2 Inflow Area =0.160 ac,43.75% Impervious, Inflow Depth = 5.90" for 100-yr event Inflow=1.38 cfs @ 12.17 hrs, Volume=0.079 af Outflow=0.02 cfs @ 18.19 hrs, Volume=0.066 af, Atten= 99%, Lag= 361.3 min Primary=0.02 cfs @ 18.19 hrs, Volume=0.066 af Routed to Reach 1R : To NW Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 1,011.81' @ 18.19 hrs Surf.Area= 1,577 sf Storage= 2,757 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 1,459.2 min ( 2,236.3 - 777.0 ) VolumeInvertAvail.StorageStorage Description Custom Stage Data (Prismatic) #11,009.00'3,950 cf Listed below (Recalc) ElevationSurf.AreaInc.StoreCum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 1,009.0046000 1,010.509801,0801,080 1,012.501,8902,8703,950 DeviceRoutingInvertOutlet Devices 0.450 in/hr Exfiltration over Surface area #1Device 21,009.00' 6.0" Round 6" Draintile #2Device 31,007.50' L= 40.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,007.50' / 1,007.30' S= 0.0050 '/' Cc= 0.900 n= 0.011 PVC, smooth interior, Flow Area= 0.20 sf 12.0" Round Culvert #3Primary1,007.30' L= 150.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,007.30' / 1,006.60' S= 0.0047 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.02 cfs @ 18.19 hrs HW=1,011.81' TW=0.00' (Dynamic Tailwater) 3=Culvert (Passes 0.02 cfs of 5.19 cfs potential flow) 2=6" Draintile (Passes 0.02 cfs of 1.63 cfs potential flow) 1=Exfiltration (Exfiltration Controls 0.02 cfs) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 44 Pond 1P: Filtration Basin 2 Hydrograph Inflow Primary 1.38 cfs Inflow Area=0.160 ac Peak Elev=1,011.81' Storage=2,757 cf 1 ) s f c ( w o l F 0.02 cfs 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 45 Summary for Pond 2P: Filtration Basin 2 Inflow Area =0.320 ac,40.63% Impervious, Inflow Depth = 5.79" for 100-yr event Inflow=2.72 cfs @ 12.17 hrs, Volume=0.154 af Outflow=0.03 cfs @ 19.72 hrs, Volume=0.112 af, Atten= 99%, Lag= 452.8 min Primary=0.03 cfs @ 19.72 hrs, Volume=0.112 af Routed to Reach 2R : To NE Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 1,008.38' @ 19.72 hrs Surf.Area= 2,484 sf Storage= 5,575 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 1,522.2 min ( 2,301.4 - 779.2 ) VolumeInvertAvail.StorageStorage Description Custom Stage Data (Prismatic) #11,005.00'5,881 cf Listed below (Recalc) ElevationSurf.AreaInc.StoreCum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 1,005.0090000 1,006.501,5201,8151,815 1,008.502,5464,0665,881 DeviceRoutingInvertOutlet Devices 0.450 in/hr Exfiltration over Surface area #1Device 21,005.00' 6.0" Round 6" Draintile #2Device 31,003.50' L= 50.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,003.50' / 1,003.25' S= 0.0050 '/' Cc= 0.900 n= 0.011 PVC, smooth interior, Flow Area= 0.20 sf 12.0" Round Culvert #3Primary1,003.25' L= 125.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 1,003.25' / 1,002.60' S= 0.0052 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.03 cfs @ 19.72 hrs HW=1,008.38' TW=0.00' (Dynamic Tailwater) 3=Culvert (Passes 0.03 cfs of 5.92 cfs potential flow) 2=6" Draintile (Passes 0.03 cfs of 1.63 cfs potential flow) 1=Exfiltration (Exfiltration Controls 0.03 cfs) 24-08-23 MSE 24-hr 3 100-yr Rainfall=7.32" Design 24-08-23 Printed 8/23/2024 Prepared by Westwood Professional Services HydroCAD® 10.20-5a s/n 02351 © 2023 HydroCAD Software Solutions LLC Page 46 Pond 2P: Filtration Basin 2 Hydrograph Inflow 3Primary 2.72 cfs Inflow Area=0.320 ac Peak Elev=1,008.38' Storage=5,575 cf 2 ) s f c ( w o l F 1 0.03 cfs 0 024681012141618202224262830323436384042444648505254565860626466687072 Time (hours)