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36 Hampden st Appendix A HydroCAD Report 8-31-2020The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report APPENDIX A Standard 2 Peak Rate Calculations HydroCAD 5-30-20208-31-2020 10yr, and 100 yr storms 8/31/2020 Table of Contents36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC TABLE OF CONTENTS Project Reports 1 Routing Diagram 2 Rainfall Events Listing 3 Area Listing (all nodes) 4 Soil Listing (all nodes) 5 Ground Covers (all nodes) 6 Pipe Listing (all nodes) 10-Year Event 7 Node Listing 8 Subcat 1PS: PS1 9 Subcat 2PS: S2 11 Pond 1P: Drop Structure 13 Pond MHC1: Drain in Drive 16 Pond Y1: Yard MH 18 Link 3L: Flow over parking 19 Link 4L: Yard overflow 20 Link Prop: Total Proposed 100-Year Event 21 Node Listing 22 Subcat 1PS: PS1 23 Subcat 2PS: S2 25 Pond 1P: Drop Structure 27 Pond MHC1: Drain in Drive 30 Pond Y1: Yard MH 32 Link 3L: Flow over parking 33 Link 4L: Yard overflow 34 Link Prop: Total Proposed 1PS PS1 2PS S2 1P Drop Structure MHC1 Drain in Drive Y1 Yard MH 3L Flow over parking 4L Yard overflow Prop Total Proposed Routing Diagram for 36 Hampden Noho Proposed 8-31-2020 Prepared by The Engineer Group, LLC, Printed 8/31/2020 HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link 36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 2HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Rainfall Events Listing Event#Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 1-Year Type III 24-hr Default 24.00 1 2.55 2 2 2-Year Type III 24-hr Default 24.00 1 3.09 2 3 5-Year Type III 24-hr Default 24.00 1 4.11 2 4 10-Year Type III 24-hr Default 24.00 1 4.95 2 5 25-Year Type III 24-hr Default 24.00 1 6.12 2 6 50-Year Type III 24-hr Default 24.00 1 6.97 2 7 100-Year Type III 24-hr Default 24.00 1 7.91 2 36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 3HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.195 39 >75% Grass cover, Good, HSG A (1PS, 2PS) 0.084 35 Brush, Fair, HSG A (2PS) 0.237 77 Brush, Fair, HSG D (2PS) 0.017 96 Gravel surface, HSG A (1PS) 0.016 98 Imp Decks (2PS) 0.086 98 Paved parking & Walks, HSG A (1PS) 0.081 98 Paved parking, HSG A (1PS, 2PS) 0.072 98 Unconnected roofs, HSG A (1PS, 2PS) 0.033 98 Unconnected roofs, HSG A Prop Bldg (2PS) 0.821 71 TOTAL AREA 36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 4HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.568 HSG A 1PS, 2PS 0.000 HSG B 0.000 HSG C 0.237 HSG D 2PS 0.016 Other 2PS 0.821 TOTAL AREA 36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 5HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.195 0.000 0.000 0.000 0.000 0.195 >75% Grass cover, Good 1PS, 2PS 0.084 0.000 0.000 0.237 0.000 0.321 Brush, Fair 2PS 0.017 0.000 0.000 0.000 0.000 0.017 Gravel surface 1PS 0.000 0.000 0.000 0.000 0.016 0.016 Imp Decks 2PS 0.081 0.000 0.000 0.000 0.000 0.081 Paved parking 1PS, 2PS 0.086 0.000 0.000 0.000 0.000 0.086 Paved parking & Walks 1PS 0.104 0.000 0.000 0.000 0.000 0.104 Unconnected roofs 1PS, 2PS 0.568 0.000 0.000 0.237 0.016 0.821 TOTAL AREA 36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 6HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line#Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Diam/Width (inches) Height (inches) Inside-Fill (inches) 1 1P 120.50 119.00 10.0 0.1500 0.010 4.0 0.0 0.0 2 MHC1 132.60 130.00 48.0 0.0542 0.010 6.0 0.0 0.0 3 Y1 129.50 126.50 55.0 0.0545 0.013 6.0 0.0 0.0 Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 7HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 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=14,079 sf 67.26% Impervious Runoff Depth=3.03"Subcatchment 1PS: PS1 Flow Length=170' Tc=2.1 min CN=82 Runoff=1.32 cfs 0.082 af Runoff Area=21,662 sf 14.06% Impervious Runoff Depth=1.48"Subcatchment 2PS: S2 Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 Runoff=0.86 cfs 0.061 af Peak Elev=121.53' Storage=8 cf Inflow=0.31 cfs 0.080 afPond 1P: Drop Structure 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' Outflow=0.31 cfs 0.080 af Peak Elev=134.27' Storage=1,040 cf Inflow=1.32 cfs 0.082 afPond MHC1: Drain in Drive Primary=0.31 cfs 0.080 af Secondary=0.00 cfs 0.000 af Outflow=0.31 cfs 0.080 af Peak Elev=129.86' Storage=3 cf Inflow=0.31 cfs 0.080 afPond Y1: Yard MH Primary=0.31 cfs 0.080 af Secondary=0.00 cfs 0.000 af Outflow=0.31 cfs 0.080 af Inflow=0.00 cfs 0.000 afLink 3L: Flow over parking Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afLink 4L: Yard overflow Primary=0.00 cfs 0.000 af Inflow=1.14 cfs 0.141 afLink Prop: Total Proposed Primary=1.14 cfs 0.141 af Total Runoff Area = 0.821 ac Runoff Volume = 0.143 af Average Runoff Depth = 2.09" 64.98% Pervious = 0.533 ac 35.02% Impervious = 0.287 ac Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 8HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1PS: PS1 Runoff =1.32 cfs @ 12.03 hrs, Volume=0.082 af, Depth=3.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.95" Area (sf)CN Description 3,853 39 >75% Grass cover, Good, HSG A 1,420 98 Unconnected roofs, HSG A 967 98 Unconnected roofs, HSG A *3,735 98 Paved parking & Walks, HSG A *3,348 98 Paved parking, HSG A 756 96 Gravel surface, HSG A 14,079 82 Weighted Average 4,609 32.74% Pervious Area 9,470 67.26% Impervious Area 2,387 25.21% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.5 80 0.0250 0.86 Sheet Flow, gar - drain n= 0.020 P2= 3.00" 0.6 90 0.0174 2.68 Shallow Concentrated Flow, gar - drain2 Paved Kv= 20.3 fps 2.1 170 Total Subcatchment 1PS: PS1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 10-Year Rainfall=4.95" Runoff Area=14,079 sf Runoff Volume=0.082 af Runoff Depth=3.03" Flow Length=170' Tc=2.1 min CN=82 1.32 cfs Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 9HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2PS: S2 Runoff =0.86 cfs @ 12.07 hrs, Volume=0.061 af, Depth=1.48" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.95" Area (sf)CN Adj Description *1,420 98 Unconnected roofs, HSG A Prop Bldg 733 98 Unconnected roofs, HSG A 4,633 39 >75% Grass cover, Good, HSG A 3,672 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 186 98 Paved parking, HSG A *707 98 Imp Decks 21,662 65 63 Weighted Average, UI Adjusted 18,616 85.94% Pervious Area 3,046 14.06% Impervious Area 2,153 70.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.8 42 0.2200 0.25 Sheet Flow, Gar to Brush Grass: Dense n= 0.240 P2= 3.00" 1.2 86 0.2200 1.17 Shallow Concentrated Flow, Brush to Botom Forest w/Heavy Litter Kv= 2.5 fps 4.0 128 Total Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 10HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2PS: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 10-Year Rainfall=4.95" Runoff Area=21,662 sf Runoff Volume=0.061 af Runoff Depth=1.48" Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 0.86 cfs Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 11HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1P: Drop Structure Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 2.98" for 10-Year event Inflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af Outflow =0.31 cfs @ 12.41 hrs, Volume=0.080 af, Atten= 0%, Lag= 0.2 min Primary =0.31 cfs @ 12.41 hrs, Volume=0.080 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 121.53' @ 12.41 hrs Surf.Area= 2 sf Storage= 8 cf Plug-Flow detention time= 1.6 min calculated for 0.080 af (100% of inflow) Center-of-Mass det. time= 0.6 min ( 846.5 - 845.9 ) Volume Invert Avail.Storage Storage Description #1 117.50'28 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 117.50 2 0 0 131.50 2 28 28 Device Routing Invert Outlet Devices #1 Primary 120.50'4.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 120.50' / 119.00' S= 0.1500 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf Primary OutFlow Max=0.31 cfs @ 12.41 hrs HW=121.53' TW=0.00' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.31 cfs @ 3.53 fps) Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 12HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1P: Drop Structure Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.323 ac Peak Elev=121.53' Storage=8 cf 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' 0.31 cfs 0.31 cfs Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 13HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond MHC1: Drain in Drive Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 3.03" for 10-Year event Inflow =1.32 cfs @ 12.03 hrs, Volume=0.082 af Outflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af, Atten= 77%, Lag= 22.2 min Primary =0.31 cfs @ 12.40 hrs, Volume=0.080 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 134.27' @ 12.40 hrs Surf.Area= 1,249 sf Storage= 1,040 cf Flood Elev= 138.01' Surf.Area= 2,729 sf Storage= 2,371 cf Plug-Flow detention time= 42.6 min calculated for 0.080 af (98% of inflow) Center-of-Mass det. time= 32.6 min ( 845.6 - 813.1 ) Volume Invert Avail.Storage Storage Description #1A 132.79'1,144 cf 14.50'W x 84.75'L x 3.04'H Field A 3,738 cf Overall - 877 cf Embedded = 2,861 cf x 40.0% Voids #2A 133.79'877 cf Cultec R-150XLHD x 32 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows #3 129.75'350 cf Manhole (Prismatic) Listed below (Recalc) 2,371 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.75 20 0 0 137.75 20 160 160 138.00 1,500 190 350 Device Routing Invert Outlet Devices #1 Primary 132.60'6.0" Round Culvert L= 48.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 132.60' / 130.00' S= 0.0542 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #2 Device 1 132.70'3.1" Vert. Orifice 1 C= 0.610 Limited to weir flow at low heads #3 Secondary 137.95'8.0' long (Profile 6) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.12 3.41 3.59 Primary OutFlow Max=0.31 cfs @ 12.40 hrs HW=134.27' TW=129.86' (Dynamic Tailwater) 1=Culvert (Passes 0.31 cfs of 0.89 cfs potential flow) 2=Orifice 1 (Orifice Controls 0.31 cfs @ 5.87 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.75' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 14HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive - Chamber Wizard Field A Chamber Model = Cultec R-150XLHD (Cultec Recharger® 150XLHD) Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows 33.0" Wide + 6.0" Spacing = 39.0" C-C Row Spacing 8 Chambers/Row x 10.25' Long +0.75' Row Adjustment = 82.75' Row Length +12.0" End Stone x 2 = 84.75' Base Length 4 Rows x 33.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 14.50' Base Width 12.0" Stone Base + 18.5" Chamber Height + 6.0" Stone Cover = 3.04' Field Height 32 Chambers x 27.2 cf +0.75' Row Adjustment x 2.65 sf x 4 Rows = 876.8 cf Chamber Storage 3,737.8 cf Field - 876.8 cf Chambers = 2,861.0 cf Stone x 40.0% Voids = 1,144.4 cf Stone Storage Chamber Storage + Stone Storage = 2,021.2 cf = 0.046 af Overall Storage Efficiency = 54.1% Overall System Size = 84.75' x 14.50' x 3.04' 32 Chambers 138.4 cy Field 106.0 cy Stone 1 Membrane Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 15HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.323 ac Peak Elev=134.27' Storage=1,040 cf 1.32 cfs 0.31 cfs 0.31 cfs 0.00 cfs Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 16HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond Y1: Yard MH Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 2.98" for 10-Year event Inflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af Outflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af, Atten= 0%, Lag= 0.0 min Primary =0.31 cfs @ 12.40 hrs, Volume=0.080 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 129.86' @ 12.40 hrs Surf.Area= 4 sf Storage= 3 cf Flood Elev= 133.00' Surf.Area= 4 sf Storage= 14 cf Plug-Flow detention time= 0.7 min calculated for 0.080 af (100% of inflow) Center-of-Mass det. time= 0.3 min ( 845.9 - 845.6 ) Volume Invert Avail.Storage Storage Description #1 129.00'14 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.00 4 0 0 132.50 4 14 14 Device Routing Invert Outlet Devices #1 Primary 129.50'6.0" Round Culvert L= 55.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 129.50' / 126.50' S= 0.0545 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.20 sf #2 Secondary 132.25'8.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 1.97 2.46 2.95 3.94 Coef. (English) 2.61 2.64 2.81 2.83 3.06 3.19 3.33 Primary OutFlow Max=0.31 cfs @ 12.40 hrs HW=129.86' TW=121.53' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.31 cfs @ 2.04 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 17HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond Y1: Yard MH Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.323 ac Peak Elev=129.86' Storage=3 cf 0.31 cfs 0.31 cfs 0.31 cfs 0.00 cfs Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 18HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Flow over parking Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 3L: Flow over parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 19HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Yard overflow Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 4L: Yard overflow Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 20HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Prop: Total Proposed Inflow Area =0.821 ac,35.02% Impervious, Inflow Depth = 2.07" for 10-Year event Inflow =1.14 cfs @ 12.07 hrs, Volume=0.141 af Primary =1.14 cfs @ 12.07 hrs, Volume=0.141 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Prop: Total Proposed Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.821 ac 1.14 cfs 1.14 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 21HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 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=14,079 sf 67.26% Impervious Runoff Depth=5.77"Subcatchment 1PS: PS1 Flow Length=170' Tc=2.1 min CN=82 Runoff=2.46 cfs 0.156 af Runoff Area=21,662 sf 14.06% Impervious Runoff Depth=3.60"Subcatchment 2PS: S2 Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 Runoff=2.24 cfs 0.149 af Peak Elev=123.64' Storage=12 cf Inflow=0.57 cfs 0.154 afPond 1P: Drop Structure 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' Outflow=0.57 cfs 0.154 af Peak Elev=137.81' Storage=2,192 cf Inflow=2.46 cfs 0.156 afPond MHC1: Drain in Drive Primary=0.57 cfs 0.154 af Secondary=0.00 cfs 0.000 af Outflow=0.57 cfs 0.154 af Peak Elev=130.12' Storage=4 cf Inflow=0.57 cfs 0.154 afPond Y1: Yard MH Primary=0.57 cfs 0.154 af Secondary=0.00 cfs 0.000 af Outflow=0.57 cfs 0.154 af Inflow=0.00 cfs 0.000 afLink 3L: Flow over parking Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afLink 4L: Yard overflow Primary=0.00 cfs 0.000 af Inflow=2.60 cfs 0.303 afLink Prop: Total Proposed Primary=2.60 cfs 0.303 af Total Runoff Area = 0.821 ac Runoff Volume = 0.305 af Average Runoff Depth = 4.46" 64.98% Pervious = 0.533 ac 35.02% Impervious = 0.287 ac Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 22HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1PS: PS1 Runoff =2.46 cfs @ 12.03 hrs, Volume=0.156 af, Depth=5.77" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.91" Area (sf)CN Description 3,853 39 >75% Grass cover, Good, HSG A 1,420 98 Unconnected roofs, HSG A 967 98 Unconnected roofs, HSG A *3,735 98 Paved parking & Walks, HSG A *3,348 98 Paved parking, HSG A 756 96 Gravel surface, HSG A 14,079 82 Weighted Average 4,609 32.74% Pervious Area 9,470 67.26% Impervious Area 2,387 25.21% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.5 80 0.0250 0.86 Sheet Flow, gar - drain n= 0.020 P2= 3.00" 0.6 90 0.0174 2.68 Shallow Concentrated Flow, gar - drain2 Paved Kv= 20.3 fps 2.1 170 Total Subcatchment 1PS: PS1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Type III 24-hr 100-Year Rainfall=7.91" Runoff Area=14,079 sf Runoff Volume=0.156 af Runoff Depth=5.77" Flow Length=170' Tc=2.1 min CN=82 2.46 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 23HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2PS: S2 Runoff =2.24 cfs @ 12.06 hrs, Volume=0.149 af, Depth=3.60" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.91" Area (sf)CN Adj Description *1,420 98 Unconnected roofs, HSG A Prop Bldg 733 98 Unconnected roofs, HSG A 4,633 39 >75% Grass cover, Good, HSG A 3,672 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 186 98 Paved parking, HSG A *707 98 Imp Decks 21,662 65 63 Weighted Average, UI Adjusted 18,616 85.94% Pervious Area 3,046 14.06% Impervious Area 2,153 70.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.8 42 0.2200 0.25 Sheet Flow, Gar to Brush Grass: Dense n= 0.240 P2= 3.00" 1.2 86 0.2200 1.17 Shallow Concentrated Flow, Brush to Botom Forest w/Heavy Litter Kv= 2.5 fps 4.0 128 Total Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 24HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2PS: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Type III 24-hr 100-Year Rainfall=7.91" Runoff Area=21,662 sf Runoff Volume=0.149 af Runoff Depth=3.60" Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 2.24 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 25HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1P: Drop Structure Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 5.72" for 100-Year event Inflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af Outflow =0.57 cfs @ 12.40 hrs, Volume=0.154 af, Atten= 0%, Lag= 0.4 min Primary =0.57 cfs @ 12.40 hrs, Volume=0.154 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 123.64' @ 12.40 hrs Surf.Area= 2 sf Storage= 12 cf Plug-Flow detention time= 1.0 min calculated for 0.154 af (100% of inflow) Center-of-Mass det. time= 0.5 min ( 842.5 - 842.0 ) Volume Invert Avail.Storage Storage Description #1 117.50'28 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 117.50 2 0 0 131.50 2 28 28 Device Routing Invert Outlet Devices #1 Primary 120.50'4.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 120.50' / 119.00' S= 0.1500 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf Primary OutFlow Max=0.57 cfs @ 12.40 hrs HW=123.64' TW=0.00' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.57 cfs @ 6.56 fps) Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 26HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1P: Drop Structure Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.323 ac Peak Elev=123.64' Storage=12 cf 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' 0.57 cfs 0.57 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 27HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond MHC1: Drain in Drive Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 5.77" for 100-Year event Inflow =2.46 cfs @ 12.03 hrs, Volume=0.156 af Outflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af, Atten= 77%, Lag= 21.4 min Primary =0.57 cfs @ 12.39 hrs, Volume=0.154 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 137.81' @ 12.39 hrs Surf.Area= 1,582 sf Storage= 2,192 cf Flood Elev= 138.01' Surf.Area= 2,729 sf Storage= 2,371 cf Plug-Flow detention time= 52.5 min calculated for 0.154 af (99% of inflow) Center-of-Mass det. time= 46.9 min ( 841.8 - 794.9 ) Volume Invert Avail.Storage Storage Description #1A 132.79'1,144 cf 14.50'W x 84.75'L x 3.04'H Field A 3,738 cf Overall - 877 cf Embedded = 2,861 cf x 40.0% Voids #2A 133.79'877 cf Cultec R-150XLHD x 32 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows #3 129.75'350 cf Manhole (Prismatic) Listed below (Recalc) 2,371 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.75 20 0 0 137.75 20 160 160 138.00 1,500 190 350 Device Routing Invert Outlet Devices #1 Primary 132.60'6.0" Round Culvert L= 48.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 132.60' / 130.00' S= 0.0542 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #2 Device 1 132.70'3.1" Vert. Orifice 1 C= 0.610 Limited to weir flow at low heads #3 Secondary 137.95'8.0' long (Profile 6) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.12 3.41 3.59 Primary OutFlow Max=0.57 cfs @ 12.39 hrs HW=137.81' TW=130.12' (Dynamic Tailwater) 1=Culvert (Passes 0.57 cfs of 1.66 cfs potential flow) 2=Orifice 1 (Orifice Controls 0.57 cfs @ 10.92 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.75' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 28HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive - Chamber Wizard Field A Chamber Model = Cultec R-150XLHD (Cultec Recharger® 150XLHD) Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows 33.0" Wide + 6.0" Spacing = 39.0" C-C Row Spacing 8 Chambers/Row x 10.25' Long +0.75' Row Adjustment = 82.75' Row Length +12.0" End Stone x 2 = 84.75' Base Length 4 Rows x 33.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 14.50' Base Width 12.0" Stone Base + 18.5" Chamber Height + 6.0" Stone Cover = 3.04' Field Height 32 Chambers x 27.2 cf +0.75' Row Adjustment x 2.65 sf x 4 Rows = 876.8 cf Chamber Storage 3,737.8 cf Field - 876.8 cf Chambers = 2,861.0 cf Stone x 40.0% Voids = 1,144.4 cf Stone Storage Chamber Storage + Stone Storage = 2,021.2 cf = 0.046 af Overall Storage Efficiency = 54.1% Overall System Size = 84.75' x 14.50' x 3.04' 32 Chambers 138.4 cy Field 106.0 cy Stone 1 Membrane Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 29HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=0.323 ac Peak Elev=137.81' Storage=2,192 cf 2.46 cfs 0.57 cfs 0.57 cfs 0.00 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 30HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond Y1: Yard MH Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 5.72" for 100-Year event Inflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af Outflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af, Atten= 0%, Lag= 0.1 min Primary =0.57 cfs @ 12.39 hrs, Volume=0.154 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 130.12' @ 12.39 hrs Surf.Area= 4 sf Storage= 4 cf Flood Elev= 133.00' Surf.Area= 4 sf Storage= 14 cf Plug-Flow detention time= 0.4 min calculated for 0.154 af (100% of inflow) Center-of-Mass det. time= 0.2 min ( 842.0 - 841.8 ) Volume Invert Avail.Storage Storage Description #1 129.00'14 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.00 4 0 0 132.50 4 14 14 Device Routing Invert Outlet Devices #1 Primary 129.50'6.0" Round Culvert L= 55.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 129.50' / 126.50' S= 0.0545 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.20 sf #2 Secondary 132.25'8.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 1.97 2.46 2.95 3.94 Coef. (English) 2.61 2.64 2.81 2.83 3.06 3.19 3.33 Primary OutFlow Max=0.57 cfs @ 12.39 hrs HW=130.12' TW=123.64' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.57 cfs @ 2.92 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 31HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond Y1: Yard MH Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.323 ac Peak Elev=130.12' Storage=4 cf 0.57 cfs 0.57 cfs 0.57 cfs 0.00 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 32HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Flow over parking Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 3L: Flow over parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 33HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Yard overflow Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 4L: Yard overflow Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 8/31/2020Prepared by The Engineer Group, LLC Page 34HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Prop: Total Proposed Inflow Area =0.821 ac,35.02% Impervious, Inflow Depth = 4.43" for 100-Year event Inflow =2.60 cfs @ 12.06 hrs, Volume=0.303 af Primary =2.60 cfs @ 12.06 hrs, Volume=0.303 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Prop: Total Proposed Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=0.821 ac 2.60 cfs 2.60 cfs