Drainage Report

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment 45S: Basin 2-2 pre-development Runoff = 1.16 cfs @ 12.22 hrs, Volume= 0.116 af, Depth= 0.97" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 2-Year Rainfall=3.44" Area (sf) CN Description 62,290 70 Woods, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 100 0.0700 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.44" 0.7 30 0.0200 0.71 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 13.3 130 Total Subcatchment 45S: Basin 2-2 pre-development Hydrograph Runoff 1.16 cfs NOAA 24-hr D 1 2-Year Rainfall=3.44" Runoff Area=62,290 sf Runoff Volume=0.116 af Flow (cfs) Runoff Depth=0.97"

(cfs) Runoff Depth=0.97" Flow Length=130' Tc=13.3 min CN=70/0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 12 Summary for Pond 42P: Pond 2-2 Inflow Area = 1.412 ac, Inflow Depth = 2.51" for 2-Year event Inflow = 3.19 cfs @ 12.17 hrs, Volume= 0.295 af Outflow = 0.11 cfs @ 16.35 hrs, Volume= 0.099 af, Atten= 96%, Lag= 250.8 min Primary = 0.11 cfs @ 16.35 hrs, Volume= 0.099 af Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 543.40' @ 16.35 hrs Surf.Area= 7,112 sf Storage= 9,963 cf Plug-Flow detention time= 697.8 min calculated for 0.099 af (33% of inflow) Center-of-Mass det. time= 519.2 min ( 1,305.5 - 786.3 ) Volume Invert Avail.Storage Storage Description #1 542.00' 28,448 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 542.00 7,112 0 0 546.00 7,112 28,448 28,448 Device Routing Invert Outlet Devices #1 Primary 543.20' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 543.75' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.11 cfs @ 16.35 hrs HW=543.40' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.11 cfs @ 1.53 fps) 2=Orifice/Grate ( Controls 0.00 cfs)

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 13 Pond 42P: Pond 2-2 Hydrograph Inflow 3.19 cfs Primary Inflow Area=1.412 ac 3 Peak Elev=543.40' Storage=9,963 cf Flow (cfs) 2 1 0.11 cfs 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 14 Time span=0.00-72.00 hrs, dt=0.05 hrs, 1441 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 36S: Basin 2-2 Runoff Area=61,497 sf Runoff Depth=4.17" Flow Length=606' Tc=10.0 min CN=80/98 Runoff=5.27 cfs 0.490 af Subcatchment 45S: Basin 2-2 pre-development Runoff Area=62,290 sf Runoff Depth=2.20" Flow Length=130' Tc=13.3 min CN=70/0 Runoff=2.80 cfs 0.262 af Pond 42P: Pond 2-2 Peak Elev=543.84' Storage=13,078 cf Inflow=5.27 cfs 0.490 af Outflow=0.61 cfs 0.294 af Total Runoff Area = 2.842 ac Runoff Volume = 0.753 af Average Runoff Depth = 3.18"

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 15 Summary for Subcatchment 36S: Basin 2-2 [47] Hint: Peak is 371% of capacity of segment #3 Runoff = 5.27 cfs @ 12.17 hrs, Volume= 0.490 af, Depth= 4.17" Routed to Pond 42P : Pond 2-2 Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) CN Description 34,605 98 Paved parking, HSG C 19,780 74 >75% Grass cover, Good, HSG C 7,112 98 Water Surface, 0% imp, HSG C 61,497 90 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.0 60 0.1300 0.34 Sheet Flow, Grass: Short n= 0.150 P2= 3.44" 0.5 120 0.0450 4.31 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.1 426 0.0350 6.20 1.42 Pipe Channel, 12.0" Round w/ 8.0" inside fill Area= 0.2 sf Perim= 2.2' r= 0.11' n= 0.010 4.6 606 Total, Increased to minimum Tc = 10.0 min

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 16 Subcatchment 36S: Basin 2-2 Hydrograph Runoff 5.27 cfs 5 NOAA 24-hr D 10-Year Rainfall=5.22" 4 Runoff Area=61,497 sf Runoff Volume=0.490 af Flow (cfs) 3 Runoff Depth=4.17" Flow Length=606' 2 Tc=10.0 min CN=80/98 1 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment 45S: Basin 2-2 pre-development Runoff = 2.80 cfs @ 12.22 hrs, Volume= 0.262 af, Depth= 2.20" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) CN Description 62,290 70 Woods, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 100 0.0700 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.44" 0.7 30 0.0200 0.71 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 13.3 130 Total Subcatchment 45S: Basin 2-2 pre-development Hydrograph Runoff 3 2.80 cfs NOAA 24-hr D 10-Year Rainfall=5.22" Runoff Area=62,290 sf 2 Runoff Volume=0.262 af Flow (cfs) Runoff Depth=2.20"

Runoff Volume=0.262 af Flow (cfs) Runoff Depth=2.20" Flow Length=130' Tc=13.3 min 1 CN=70/0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

Basdin 2-2 without Exfiltration Proposed Basin 2-2 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 18 Summary for Pond 42P: Pond 2-2 Inflow Area = 1.412 ac, Inflow Depth = 4.17" for 10-Year event Inflow = 5.27 cfs @ 12.17 hrs, Volume= 0.490 af Outflow = 0.61 cfs @ 13.15 hrs, Volume= 0.294 af, Atten= 88%, Lag= 58.7 min Primary = 0.61 cfs @ 13.15 hrs, Volume= 0.294 af Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 543.84' @ 13.15 hrs Surf.Area= 7,112 sf Storage= 13,078 cf Plug-Flow detention time= 402.4 min calculated for 0.294 af (60% of inflow) Center-of-Mass det. time= 283.0 min ( 1,061.2 - 778.2 ) Volume Invert Avail.Storage Storage Description #1 542.00' 28,448 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 542.00 7,112 0 0 546.00 7,112 28,448 28,448 Device Routing Invert Outlet Devices #1 Primary 543.20' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 543.75' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.61 cfs @ 13.15 hrs HW=543.84' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.59 cfs @ 3.00 fps) 2=Orifice/Grate (Orifice Controls 0.02 cfs @ 1.01 fps)