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HomeMy WebLinkAbout20250121_NOI_CCS_Part 6_Part3Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 19HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 5P: Isolated Wetland Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.052 0.05 0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.629 ac Peak Elev=138.52' Storage=596 cf 0.05 cfs 0.00 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 20HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 1L: Offsite-South Inflow Area = 0.967 ac, 0.00% Impervious, Inflow Depth = 0.02" for 10 yr - 24 hr event Inflow = 0.00 cfs @ 21.38 hrs, Volume= 0.002 af Primary = 0.00 cfs @ 21.38 hrs, Volume= 0.002 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 1L: Offsite-South Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 Inflow Area=0.967 ac 0.00 cfs0.00 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 21HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 2L: Offsite-North Inflow Area = 2.118 ac, 3.27% Impervious, Inflow Depth = 0.13" for 10 yr - 24 hr event Inflow = 0.05 cfs @ 12.49 hrs, Volume= 0.024 af Primary = 0.05 cfs @ 12.49 hrs, Volume= 0.024 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 2L: Offsite-North Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.054 0.052 0.05 0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=2.118 ac 0.05 cfs0.05 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 22HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: EDA-01 Runoff = 0.12 cfs @ 12.40 hrs, Volume= 0.033 af, Depth= 0.41" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description 40,710 30 Woods, Good, HSG A 18 35 Brush, Fair, HSG A 1,378 96 Gravel surface, HSG A 42,106 32 Weighted Average 42,106 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 1S: EDA-01 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.135 0.13 0.125 0.12 0.115 0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Runoff Area=42,106 sf Runoff Volume=0.033 af Runoff Depth=0.41" Tc=6.0 min CN=32 0.12 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 23HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: EDA-02 Runoff = 4.77 cfs @ 12.08 hrs, Volume= 0.353 af, Depth= 5.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description * 23,343 98 Substation Yard Stone (Basin) 3,735 35 Brush, Fair, HSG A * 2,893 98 Impervious 1,412 30 Woods, Good, HSG A 31,383 87 Weighted Average 5,147 16.40% Pervious Area 26,236 83.60% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 2S: EDA-02 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)5 4 3 2 1 0 Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Runoff Area=31,383 sf Runoff Volume=0.353 af Runoff Depth=5.89" Tc=6.0 min CN=87 4.77 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 24HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: EDA-03 Runoff = 0.90 cfs @ 12.13 hrs, Volume= 0.115 af, Depth= 0.92" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description 32,573 30 Woods, Good, HSG A 6,367 96 Gravel surface, HSG A 25,117 35 Brush, Fair, HSG A * 441 85 Substation Yard Stone (Non-Basin) * 335 98 Impervious 64,833 39 Weighted Average 64,498 99.48% Pervious Area 335 0.52% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 3S: EDA-03 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Runoff Area=64,833 sf Runoff Volume=0.115 af Runoff Depth=0.92" Tc=6.0 min CN=39 0.90 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 25HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: EDA-04 Runoff = 0.53 cfs @ 12.12 hrs, Volume= 0.057 af, Depth= 1.09" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description *11 85 Substation Yard Stone (Non-Basin) 24,711 35 Brush, Fair, HSG A 16 96 Gravel surface, HSG A * 2,683 98 Wetland 27,421 41 Weighted Average 24,738 90.22% Pervious Area 2,683 9.78% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 4S: EDA-04 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)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 100 yr - 24 hr Rainfall=7.42" Runoff Area=27,421 sf Runoff Volume=0.057 af Runoff Depth=1.09" Tc=6.0 min CN=41 0.53 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 26HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1P: Substation Inflow Area = 0.720 ac, 83.60% Impervious, Inflow Depth = 5.89" for 100 yr - 24 hr event Inflow = 4.77 cfs @ 12.08 hrs, Volume= 0.353 af Outflow = 1.30 cfs @ 11.80 hrs, Volume= 0.353 af, Atten= 73%, Lag= 0.0 min Discarded = 1.30 cfs @ 11.80 hrs, Volume= 0.353 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 152.80' @ 12.44 hrs Surf.Area= 23,343 sf Storage= 2,841 cf Plug-Flow detention time= 10.4 min calculated for 0.353 af (100% of inflow) Center-of-Mass det. time= 10.4 min ( 797.9 - 787.4 ) Volume Invert Avail.Storage Storage Description #1 152.50' 5,135 cf Custom Stage Data (Prismatic) Listed below (Recalc) 12,839 cf Overall x 40.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.50 23,343 0 0 153.00 23,343 11,672 11,672 153.05 23,343 1,167 12,839 Device Routing Invert Outlet Devices #1 Primary 153.00'190.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 #2 Discarded 152.50'2.410 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.30 cfs @ 11.80 hrs HW=152.51' (Free Discharge) 2=Exfiltration (Exfiltration Controls 1.30 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=152.50' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 27HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 1P: Substation Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)5 4 3 2 1 0 Inflow Area=0.720 ac Peak Elev=152.80' Storage=2,841 cf 4.77 cfs 1.30 cfs1.30 cfs 0.00 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 28HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 5P: Isolated Wetland Inflow Area = 0.629 ac, 9.78% Impervious, Inflow Depth = 1.09" for 100 yr - 24 hr event Inflow = 0.53 cfs @ 12.12 hrs, Volume= 0.057 af Outflow = 0.04 cfs @ 16.89 hrs, Volume= 0.017 af, Atten= 93%, Lag= 286.1 min Primary = 0.04 cfs @ 16.89 hrs, Volume= 0.017 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 139.01' @ 16.89 hrs Surf.Area= 3,029 sf Storage= 1,781 cf Plug-Flow detention time= 452.5 min calculated for 0.017 af (29% of inflow) Center-of-Mass det. time= 276.9 min ( 1,187.9 - 911.0 ) Volume Invert Avail.Storage Storage Description #1 138.00' 1,909 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 138.00 486 0 0 139.00 3,029 1,758 1,758 139.05 3,029 151 1,909 Device Routing Invert Outlet Devices #1 Primary 139.00'16.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 Primary OutFlow Max=0.04 cfs @ 16.89 hrs HW=139.01' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.04 cfs @ 0.31 fps) Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 29HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 5P: Isolated Wetland Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)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=0.629 ac Peak Elev=139.01' Storage=1,781 cf 0.53 cfs 0.04 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 30HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 1L: Offsite-South Inflow Area = 0.967 ac, 0.00% Impervious, Inflow Depth = 0.41" for 100 yr - 24 hr event Inflow = 0.12 cfs @ 12.40 hrs, Volume= 0.033 af Primary = 0.12 cfs @ 12.40 hrs, Volume= 0.033 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 1L: Offsite-South Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.135 0.13 0.125 0.12 0.115 0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.967 ac 0.12 cfs0.12 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 31HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 2L: Offsite-North Inflow Area = 2.118 ac, 3.27% Impervious, Inflow Depth = 0.74" for 100 yr - 24 hr event Inflow = 0.90 cfs @ 12.13 hrs, Volume= 0.131 af Primary = 0.90 cfs @ 12.13 hrs, Volume= 0.131 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 2L: Offsite-North Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=2.118 ac 0.90 cfs0.90 cfs 5S PDA-01 6S PDA-02 7S PDA-03 8S PDA-04 3P Substation 6P Isolated Wetland 3L Offsite-South 4L Offsite-North Routing Diagram for West Barnstable Hydrologic Prepared by Burns and McDonnell, Printed 12/10/2024 HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 2HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: PDA-01 Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Area (sf)CN Description 18,172 30 Woods, Good, HSG A 15,416 30 Meadow, non-grazed, HSG A 33,588 30 Weighted Average 33,588 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 5S: PDA-01 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Runoff Area=33,588 sf Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=30 0.00 cfs Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 3HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: PDA-02 Runoff = 4.90 cfs @ 12.08 hrs, Volume= 0.375 af, Depth= 2.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Area (sf)CN Description * 44,606 98 Substation Yard Stone (Basin) * 19,784 98 Impervious 2,141 30 Meadow, non-grazed, HSG A 79 35 Brush, Fair, HSG A 66,610 96 Weighted Average 2,220 3.33% Pervious Area 64,390 96.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 6S: PDA-02 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)5 4 3 2 1 0 Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Runoff Area=66,610 sf Runoff Volume=0.375 af Runoff Depth=2.95" Tc=6.0 min CN=96 4.90 cfs Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 4HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: PDA-03 Runoff = 0.00 cfs @ 21.02 hrs, Volume= 0.001 af, Depth= 0.02" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Area (sf)CN Description 6,089 35 Brush, Fair, HSG A 2,979 96 Gravel surface, HSG A * 39 98 Impervious 6,546 30 Woods, Good, HSG A 14,062 30 Meadow, non-grazed, HSG A * 1,894 85 Substation Yard Stone (Non-Basin) 31,609 41 Weighted Average 31,570 99.88% Pervious Area 39 0.12% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 7S: PDA-03 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 0 Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Runoff Area=31,609 sf Runoff Volume=0.001 af Runoff Depth=0.02" Tc=6.0 min CN=41 0.00 cfs Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 5HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 8S: PDA-04 Runoff = 0.01 cfs @ 14.90 hrs, Volume= 0.004 af, Depth= 0.07" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Area (sf)CN Description 797 96 Gravel surface, HSG A 5,800 30 Meadow, non-grazed, HSG A 21,812 35 Brush, Fair, HSG A * 2,847 85 Substation Yard Stone (Non-Basin) * 2,683 98 Wetland 33,939 45 Weighted Average 31,256 92.09% Pervious Area 2,683 7.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 8S: PDA-04 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.008 0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Type III 24-hr 2 yr - 24 hr Rainfall=3.40" Runoff Area=33,939 sf Runoff Volume=0.004 af Runoff Depth=0.07" Tc=6.0 min CN=45 0.01 cfs Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 6HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 3P: Substation Inflow Area = 1.529 ac, 96.67% Impervious, Inflow Depth = 2.95" for 2 yr - 24 hr event Inflow = 4.90 cfs @ 12.08 hrs, Volume= 0.375 af Outflow = 2.49 cfs @ 11.99 hrs, Volume= 0.375 af, Atten= 49%, Lag= 0.0 min Discarded = 2.49 cfs @ 11.99 hrs, Volume= 0.375 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 152.57' @ 12.22 hrs Surf.Area= 44,606 sf Storage= 1,230 cf Plug-Flow detention time= 2.1 min calculated for 0.375 af (100% of inflow) Center-of-Mass det. time= 2.1 min ( 774.4 - 772.3 ) Volume Invert Avail.Storage Storage Description #1 152.50' 9,813 cf Custom Stage Data (Prismatic) Listed below (Recalc) 24,533 cf Overall x 40.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.50 44,606 0 0 153.00 44,606 22,303 22,303 153.05 44,606 2,230 24,533 Device Routing Invert Outlet Devices #1 Primary 153.00'279.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 #2 Discarded 152.50'2.410 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.49 cfs @ 11.99 hrs HW=152.51' (Free Discharge) 2=Exfiltration (Exfiltration Controls 2.49 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=152.50' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 7HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 3P: Substation Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)5 4 3 2 1 0 Inflow Area=1.529 ac Peak Elev=152.57' Storage=1,230 cf 4.90 cfs 2.49 cfs2.49 cfs 0.00 cfs Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 8HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 6P: Isolated Wetland Inflow Area = 0.779 ac, 7.91% Impervious, Inflow Depth = 0.07" for 2 yr - 24 hr event Inflow = 0.01 cfs @ 14.90 hrs, Volume= 0.004 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 138.25' @ 24.34 hrs Surf.Area= 1,110 sf Storage= 196 cf Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 138.00' 1,909 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 138.00 486 0 0 139.00 3,029 1,758 1,758 139.05 3,029 151 1,909 Device Routing Invert Outlet Devices #1 Primary 139.00'16.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=138.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 9HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 6P: Isolated Wetland Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.008 0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Inflow Area=0.779 ac Peak Elev=138.25' Storage=196 cf 0.01 cfs 0.00 cfs Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 10HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Offsite-South Inflow Area = 0.771 ac, 0.00% Impervious, Inflow Depth = 0.00" for 2 yr - 24 hr event 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= 0.00-30.00 hrs, dt= 0.01 hrs Link 3L: Offsite-South Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.771 ac 0.00 cfs0.00 cfs Type III 24-hr 2 yr - 24 hr Rainfall=3.40"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 11HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Offsite-North Inflow Area = 1.505 ac, 4.15% Impervious, Inflow Depth = 0.01" for 2 yr - 24 hr event Inflow = 0.00 cfs @ 21.02 hrs, Volume= 0.001 af Primary = 0.00 cfs @ 21.02 hrs, Volume= 0.001 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 4L: Offsite-North Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 0 Inflow Area=1.505 ac 0.00 cfs0.00 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 12HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: PDA-01 Runoff = 0.00 cfs @ 24.01 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Area (sf)CN Description 18,172 30 Woods, Good, HSG A 15,416 30 Meadow, non-grazed, HSG A 33,588 30 Weighted Average 33,588 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 5S: PDA-01 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Runoff Area=33,588 sf Runoff Volume=0.000 af Runoff Depth=0.00" Tc=6.0 min CN=30 0.00 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 13HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: PDA-02 Runoff = 7.28 cfs @ 12.08 hrs, Volume= 0.571 af, Depth= 4.48" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Area (sf)CN Description * 44,606 98 Substation Yard Stone (Basin) * 19,784 98 Impervious 2,141 30 Meadow, non-grazed, HSG A 79 35 Brush, Fair, HSG A 66,610 96 Weighted Average 2,220 3.33% Pervious Area 64,390 96.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 6S: PDA-02 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)8 7 6 5 4 3 2 1 0 Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Runoff Area=66,610 sf Runoff Volume=0.571 af Runoff Depth=4.48" Tc=6.0 min CN=96 7.28 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 14HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: PDA-03 Runoff = 0.05 cfs @ 12.42 hrs, Volume= 0.016 af, Depth= 0.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Area (sf)CN Description 6,089 35 Brush, Fair, HSG A 2,979 96 Gravel surface, HSG A * 39 98 Impervious 6,546 30 Woods, Good, HSG A 14,062 30 Meadow, non-grazed, HSG A * 1,894 85 Substation Yard Stone (Non-Basin) 31,609 41 Weighted Average 31,570 99.88% Pervious Area 39 0.12% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 7S: PDA-03 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Runoff Area=31,609 sf Runoff Volume=0.016 af Runoff Depth=0.26" Tc=6.0 min CN=41 0.05 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 15HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 8S: PDA-04 Runoff = 0.15 cfs @ 12.31 hrs, Volume= 0.028 af, Depth= 0.43" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Area (sf)CN Description 797 96 Gravel surface, HSG A 5,800 30 Meadow, non-grazed, HSG A 21,812 35 Brush, Fair, HSG A * 2,847 85 Substation Yard Stone (Non-Basin) * 2,683 98 Wetland 33,939 45 Weighted Average 31,256 92.09% Pervious Area 2,683 7.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 8S: PDA-04 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 10 yr - 24 hr Rainfall=4.95" Runoff Area=33,939 sf Runoff Volume=0.028 af Runoff Depth=0.43" Tc=6.0 min CN=45 0.15 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 16HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 3P: Substation Inflow Area = 1.529 ac, 96.67% Impervious, Inflow Depth = 4.48" for 10 yr - 24 hr event Inflow = 7.28 cfs @ 12.08 hrs, Volume= 0.571 af Outflow = 2.49 cfs @ 11.86 hrs, Volume= 0.571 af, Atten= 66%, Lag= 0.0 min Discarded = 2.49 cfs @ 11.86 hrs, Volume= 0.571 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 152.69' @ 12.35 hrs Surf.Area= 44,606 sf Storage= 3,338 cf Plug-Flow detention time= 5.7 min calculated for 0.571 af (100% of inflow) Center-of-Mass det. time= 5.7 min ( 768.4 - 762.6 ) Volume Invert Avail.Storage Storage Description #1 152.50' 9,813 cf Custom Stage Data (Prismatic) Listed below (Recalc) 24,533 cf Overall x 40.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.50 44,606 0 0 153.00 44,606 22,303 22,303 153.05 44,606 2,230 24,533 Device Routing Invert Outlet Devices #1 Primary 153.00'279.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 #2 Discarded 152.50'2.410 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.49 cfs @ 11.86 hrs HW=152.51' (Free Discharge) 2=Exfiltration (Exfiltration Controls 2.49 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=152.50' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 17HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 3P: Substation Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)8 7 6 5 4 3 2 1 0 Inflow Area=1.529 ac Peak Elev=152.69' Storage=3,338 cf 7.28 cfs 2.49 cfs2.49 cfs 0.00 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 18HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 6P: Isolated Wetland Inflow Area = 0.779 ac, 7.91% Impervious, Inflow Depth = 0.43" for 10 yr - 24 hr event Inflow = 0.15 cfs @ 12.31 hrs, Volume= 0.028 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 138.80' @ 24.34 hrs Surf.Area= 2,523 sf Storage= 1,206 cf Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 138.00' 1,909 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 138.00 486 0 0 139.00 3,029 1,758 1,758 139.05 3,029 151 1,909 Device Routing Invert Outlet Devices #1 Primary 139.00'16.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=138.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 19HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 6P: Isolated Wetland Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.779 ac Peak Elev=138.80' Storage=1,206 cf 0.15 cfs 0.00 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 20HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Offsite-South Inflow Area = 0.771 ac, 0.00% Impervious, Inflow Depth = 0.00" for 10 yr - 24 hr event Inflow = 0.00 cfs @ 24.01 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 24.01 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 3L: Offsite-South Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 Inflow Area=0.771 ac 0.00 cfs0.00 cfs Type III 24-hr 10 yr - 24 hr Rainfall=4.95"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 21HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Offsite-North Inflow Area = 1.505 ac, 4.15% Impervious, Inflow Depth = 0.13" for 10 yr - 24 hr event Inflow = 0.05 cfs @ 12.42 hrs, Volume= 0.016 af Primary = 0.05 cfs @ 12.42 hrs, Volume= 0.016 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 4L: Offsite-North Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=1.505 ac 0.05 cfs0.05 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 22HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: PDA-01 Runoff = 0.04 cfs @ 12.48 hrs, Volume= 0.019 af, Depth= 0.29" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description 18,172 30 Woods, Good, HSG A 15,416 30 Meadow, non-grazed, HSG A 33,588 30 Weighted Average 33,588 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 5S: PDA-01 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Runoff Area=33,588 sf Runoff Volume=0.019 af Runoff Depth=0.29" Tc=6.0 min CN=30 0.04 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 23HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: PDA-02 Runoff = 11.05 cfs @ 12.08 hrs, Volume= 0.885 af, Depth= 6.94" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description * 44,606 98 Substation Yard Stone (Basin) * 19,784 98 Impervious 2,141 30 Meadow, non-grazed, HSG A 79 35 Brush, Fair, HSG A 66,610 96 Weighted Average 2,220 3.33% Pervious Area 64,390 96.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 6S: PDA-02 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Runoff Area=66,610 sf Runoff Volume=0.885 af Runoff Depth=6.94" Tc=6.0 min CN=96 11.05 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 24HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: PDA-03 Runoff = 0.61 cfs @ 12.12 hrs, Volume= 0.066 af, Depth= 1.09" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description 6,089 35 Brush, Fair, HSG A 2,979 96 Gravel surface, HSG A * 39 98 Impervious 6,546 30 Woods, Good, HSG A 14,062 30 Meadow, non-grazed, HSG A * 1,894 85 Substation Yard Stone (Non-Basin) 31,609 41 Weighted Average 31,570 99.88% Pervious Area 39 0.12% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 7S: PDA-03 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)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 100 yr - 24 hr Rainfall=7.42" Runoff Area=31,609 sf Runoff Volume=0.066 af Runoff Depth=1.09" Tc=6.0 min CN=41 0.61 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 25HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 8S: PDA-04 Runoff = 1.05 cfs @ 12.11 hrs, Volume= 0.093 af, Depth= 1.44" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Area (sf)CN Description 797 96 Gravel surface, HSG A 5,800 30 Meadow, non-grazed, HSG A 21,812 35 Brush, Fair, HSG A * 2,847 85 Substation Yard Stone (Non-Basin) * 2,683 98 Wetland 33,939 45 Weighted Average 31,256 92.09% Pervious Area 2,683 7.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 8S: PDA-04 Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 100 yr - 24 hr Rainfall=7.42" Runoff Area=33,939 sf Runoff Volume=0.093 af Runoff Depth=1.44" Tc=6.0 min CN=45 1.05 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 26HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 3P: Substation Inflow Area = 1.529 ac, 96.67% Impervious, Inflow Depth = 6.94" for 100 yr - 24 hr event Inflow = 11.05 cfs @ 12.08 hrs, Volume= 0.885 af Outflow = 2.49 cfs @ 11.73 hrs, Volume= 0.885 af, Atten= 77%, Lag= 0.0 min Discarded = 2.49 cfs @ 11.73 hrs, Volume= 0.885 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 152.95' @ 12.48 hrs Surf.Area= 44,606 sf Storage= 7,981 cf Plug-Flow detention time= 15.2 min calculated for 0.885 af (100% of inflow) Center-of-Mass det. time= 15.2 min ( 769.0 - 753.8 ) Volume Invert Avail.Storage Storage Description #1 152.50' 9,813 cf Custom Stage Data (Prismatic) Listed below (Recalc) 24,533 cf Overall x 40.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.50 44,606 0 0 153.00 44,606 22,303 22,303 153.05 44,606 2,230 24,533 Device Routing Invert Outlet Devices #1 Primary 153.00'279.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 #2 Discarded 152.50'2.410 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.49 cfs @ 11.73 hrs HW=152.51' (Free Discharge) 2=Exfiltration (Exfiltration Controls 2.49 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=152.50' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 27HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 3P: Substation Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.529 ac Peak Elev=152.95' Storage=7,981 cf 11.05 cfs 2.49 cfs2.49 cfs 0.00 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 28HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Pond 6P: Isolated Wetland Inflow Area = 0.779 ac, 7.91% Impervious, Inflow Depth = 1.44" for 100 yr - 24 hr event Inflow = 1.05 cfs @ 12.11 hrs, Volume= 0.093 af Outflow = 0.15 cfs @ 13.38 hrs, Volume= 0.053 af, Atten= 86%, Lag= 76.3 min Primary = 0.15 cfs @ 13.38 hrs, Volume= 0.053 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 139.02' @ 13.38 hrs Surf.Area= 3,029 sf Storage= 1,815 cf Plug-Flow detention time= 261.0 min calculated for 0.053 af (57% of inflow) Center-of-Mass det. time= 125.1 min ( 1,018.3 - 893.3 ) Volume Invert Avail.Storage Storage Description #1 138.00' 1,909 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 138.00 486 0 0 139.00 3,029 1,758 1,758 139.05 3,029 151 1,909 Device Routing Invert Outlet Devices #1 Primary 139.00'16.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.51 3.59 3.57 Primary OutFlow Max=0.15 cfs @ 13.38 hrs HW=139.02' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.15 cfs @ 0.48 fps) Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 29HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Pond 6P: Isolated Wetland Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.779 ac Peak Elev=139.02' Storage=1,815 cf 1.05 cfs 0.15 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 30HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Offsite-South Inflow Area = 0.771 ac, 0.00% Impervious, Inflow Depth = 0.29" for 100 yr - 24 hr event Inflow = 0.04 cfs @ 12.48 hrs, Volume= 0.019 af Primary = 0.04 cfs @ 12.48 hrs, Volume= 0.019 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 3L: Offsite-South Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.771 ac 0.04 cfs0.04 cfs Type III 24-hr 100 yr - 24 hr Rainfall=7.42"West Barnstable Hydrologic Printed 12/10/2024Prepared by Burns and McDonnell Page 31HydroCAD® 10.10-4b s/n 08510 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Offsite-North Inflow Area = 1.505 ac, 4.15% Impervious, Inflow Depth = 0.95" for 100 yr - 24 hr event Inflow = 0.61 cfs @ 12.12 hrs, Volume= 0.119 af Primary = 0.61 cfs @ 12.12 hrs, Volume= 0.119 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Link 4L: Offsite-North Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)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 Inflow Area=1.505 ac 0.61 cfs0.61 cfs APPENDIX F – WQV & RECHARGE CALCULATIONS Client Page of Project Date Made By Checked By Preliminary Final WEST BARNSTABLE STATION EXPANSION WATER QUALITY VOLUME CALCULATIONS (IN ACCORDANCE WITH THE MASSACHUSETTS STORMWATER HANDBOOK 2008) PER THE MASSACHUSETTS STORMWATER HANDBOOK - STANDARD 4: "THE REQUIRED WATER QUALITY VOLUME EQUALS 1.0 INCHES OF RUNOFF TIMES THE TOTAL IMPERVIOUS AREA OF THE POST DEVELOPMENT SITE." WQVr = WATER QUALITY VOLUME REQUIRED (C.F.) = D x A D = DEPTH OF RUNOFF (INCHES) = 1.0 INCHES A = IMPERVIOUS AREA OF POST-DEVELOPMENT (S.F.) A = S.F. IMPERVIOUS AREAS INCLUDE CONTROL HOUSE, TRANSFORMER, SWITCHGEAR, AND CONCRETE FOUNDATIONS WITHIN THE WATERSHED BOUNDARY FOR THE PROJECT. WQVr = (1.0 INCHES / 12) X S.F. WQVr =C.F. THIS PROJECT WILL UTILIZES A CRUSHED STONE PAD AS AN INFILTRATION BASIN TO PROVIDE THE REQUIRED RECHARGE VOLUME. THE STORAGE VOLUME IS CALCULATED BASED ON SURFACE AREA AND ELEVATION. A VOID RATIO OF 40% WAS USED FOR STORAGE WITHIN THE STONE. PER THE TSS REMOVAL EFFICIENCIES CHART FOR BMPs IN THE MASSACHUSETTS STORMWATER HANDBOOK, AN INFILTRATION BASIN BMP HAS 80% TSS REMOVAL PROVIDED IT IS COMBINED WITH ONE OR MORE PRETREATMENT BMPs PRIOR TO INFILTRATION. IMPERVIOUS AREAS WILL SHEET FLOW DIRECTLY ONTO THE CRUSHED ROCK SURFACING, WHICH WILL PROVIDE PRETREATMENT PRIOR TO INFILTRATION WQVp =C.F. WQ VOLUME PROVIDED >WQ VOLUME REQUIRED C.F.C.F. X L. Guerin 1 R. Reed 1 12/05/24 Eversource West Barnstable Water Quality Volume Calculations 8921 1652 1652 19,823 19,823 8921 NET STONE SURFACE AREA (S.F.) STONE DEPTH (INCH) AVAILABLE STORAGE (C.F.) 44,606 6 8921 Client Page of Project Date Made By Checked By Preliminary Final WEST BARNSTABLE STATION EXPANSION RECHARGE VOLUME CALCULATIONS PER THE USDA NATIONAL ENGINEERING HANDBOOK, PART 630, CHAPTER 7: THE SITE SOILS HAVE BEEN DETERMINED TO HAVE A HYDROLOGIC SOIL GROUP 'A' WITH A RAWLS RECHARGE RATE OF 2.41 INCHES/HR. FIELD INFILTRATION TESTING INDICATE AN OBSERVED RATE OF 18.4 INCHES/ HOUR , HOWEVER, THE RAWLS RECHARGE RATE WILL BE USED FOR A MORE CONSERVATIVE DESIGN. PER THE MASSACHUSETTS STORMWATER HANDBOOK (2008) - STANDARD 3: "THE REQUIRED RECHARGE VOLUME, THE STORMWATER VOLUME THAT MUST BE INFILTRATED, SHALL BE DETERMINED USING EXISTING SITE CONDITIONS AND THE INFILTRATION RATES SET FORTH BELOW:" FOR HYDRAULIC GROUP 'A': VOLUME TO RECHARGE x TOTAL IMPERVIOUS AREA = 0.6 INCHES OF RUNOFF RVr = RECHARGE VOLUME REQUIRED (C.F.) = F x A F = DEPTH OF RUNOFF (INCHES) = 0.6 INCHES A = IMPERVIOUS AREA OF POST-DEVELOPMENT (S.F.) A = S.F. IMPERVIOUS AREAS INCLUDE CONTROL HOUSE, TRANSFORMER, SWITCHGEAR, AND CONCRETE FOUNDATIONS WITHIN THE WATERSHED BOUNDARY FOR THE PROJECT. RVr = (0.6 INCH / 12) X S.F. RVr =C.F. THIS PROJECT WILL UTILIZES A CRUSHED STONE PAD AS AN INFILTRATION BASIN TO PROVIDE THE REQUIRED RECHARGE VOLUME. THE STORAGE VOLUME IS CALCULATED BASED ON SURFACE AREA AND ELEVATION. A VOID RATIO OF 40% WAS USED FOR STORAGE WITHIN THE STONE. RVp =C.F. RECHARGE VOLUME PROVIDED >RECHARGE VOLUME REQUIRED C.F.C.F. X L. Guerin 2 R. Reed 1 12/05/24 Eversource West Barnstable Recharge Volume Calculations 991 19,823 19823 991 8921 8921 NET STONE SURFACE AREA (S.F.) STONE DEPTH (INCH) AVAILABLE STORAGE (C.F.) 44,606 6 8921 Client Page of Project Date Made By Checked By Preliminary Final CALCULATION FOR DRAWDOWN TIME (RECHARGE VOLUME) PER THE MASSACHUSETTS STORMWATER HANDBOOK, THE INFILTRATION BMP MUST DRAIN COMPLETELY WITHIN 72 HOURS Td = DRAWDOWN TIME (HOURS)= RVp / (k / 12 x Ar) RVp = RECHARGE VOLUME PROVIDED = C.F. k = RAWLS RECHARGE RATE = 2.41 IN/HR Ar = FOOTPRINT OF CRUSHED STONE PAD = S.F. Td =C.F. / (2.41 IN/HR / 12 x S.F.) Td =HOURS DRAWDOWN TIME PROVIDED <DRAWDOWN TIME REQUIRED HOURS 72 HOURS CALCULATION FOR DRAWDOWN TIME (100 YEAR STORM VOLUME) PER THE MASSACHUSETTS STORMWATER HANDBOOK, THE INFILTRATION BMP MUST DRAIN COMPLETELY WITHIN 72 HOURS Td = DRAWDOWN TIME (HOURS)= V100/ (k / 12 x Ar) V100 = 100 YEAR STORM RUNOFF VOLUME =C.F. k = RAWLS RECHARGE RATE = 2.41 IN/HR Ar = FOOTPRINT OF CRUSHED STONE PAD = S.F. Td =C.F. / (2.41 IN/HR / 12 x S.F.) Td =HOURS DRAWDOWN TIME PROVIDED <DRAWDOWN TIME REQUIRED HOURS 72 HOURS X Eversource 2 2 West Barnstable 12/05/24 R. Reed Recharge Volume Calculations L. Guerin 38,551 44,606 44,606 1.0 1.0 8,921 44,606 44,606 4.3 4.3 38,551 8,921 APPENDIX G – EROSION CONTROL PLAN & DETAILS XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXX X XX X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XX X XXXXXXXXXXXXXXXX X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 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OHW 483C 483C 483D 494C 483D 88 92 A B C D E F G H I J 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 A B C D E F G H I J WEST BARNSTABLE 345KV STATION 921-6104ISSUED FOR PERMITTING REV 22 060B NEW DRAWING 921-6105EROSION CONTROL DETAILS 921-6107FENCE & GATE DETAILS 921-6101SITE PLAN 921-6106SITE DETAILS 921-7551345kV YARD ARRANGEMENT PLAN 921-012EQUIPMENT PLAN PRIMARY WIRING 921-6102GRADING & DRAINAGE PLAN 921-6103GRADING CROSS SECTIONS appchkdsndetdateno.revisions checked detailed designed date 146695 09/04/2022 K. MARX K. MARX R. REEDA-1 12/15/22 ISSUED FOR REVIEW - PRELIMINARY KAM KAM RLR RLR A-2 04/28/23 ISSUED FOR REVIEW - FINAL PRELIMINARYKAM KAM RLR RLR A-3 05/24/24 ISSUED FOR REVIEW - PERMITTING KAM KAM RLR RLR A-4 11/11/24 ISSUED FOR REVIEW - DETAILED KAM KAM RLR RLR A-5 11/26/24 ISSUED FOR BID KAM KAM RLR RLR A-6 12/12/24 RE-ISSUED FOR REVIEW - PERMITTING KAM KAM RLR RLR A-7 01/06/25 ISSUED FOR PERMITTING KAM KAM RLR RLR Digitally Sealed 01/06/2025 Ver 3.00LAYER NAMECOLORLINETYPELINEWEIGHTLAYER NAMECOLORLINETYPELINEWEIGHTGeneralLockedCivilLAYER NAMECOLORLINETYPELINEWEIGHTLAYER NAMECOLORLINETYPELINEWEIGHTVer 3.00NomenclatureLAYER NAMECOLORLINETYPELINEWEIGHTLAYER NAMECOLORLINETYPELINEWEIGHTVer 3.00Sub StationNo PlotNo PlotLAYER NAMECOLORLINETYPELINEWEIGHTLAYER NAMECOLORLINETYPELINEWEIGHTLockedVer 3.00LAYER NAMECOLORLINETYPELINEWEIGHTSurveyVer 3.00TelcomLAYER NAMECOLORLINETYPELINEWEIGHTLAYER NAMECOLORLINETYPELINEWEIGHTVer 3.00LAYER NAMECOLORLINETYPELINEWEIGHTTransmission LineVer 3.00VendorLAYER NAMECOLORLINETYPELAYER NAMECOLORLINETYPELINEWEIGHTVer 3.00 A B C D E F G H I J 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 A B C D E F G H I J WEST BARNSTABLE 345KV STATION 921-6105ISSUED FOR PERMITTING REV 22 060B NEW DRAWING appchkdsndetdateno.revisions checked detailed designed date 146695 09/04/2022 Y. GOLE K. MARX R. REEDA-1 12/15/22 ISSUED FOR REVIEW - PRELIMINARY KAM KAM RLR RLR A-2 04/28/23 ISSUED FOR REVIEW - FINAL PRELIMINARY KAM KAM RLR RLR A-3 05/24/24 ISSUED FOR REVIEW - PERMITTING KAM KAM RLR RLR A-4 11/11/24 ISSUED FOR REVIEW - DETAILED KAM KAM RLR RLR A-5 11/26/24 ISSUED FOR BID KAM KAM RLR RLR A-6 12/12/24 RE-ISSUED FOR REVIEW - PERMITTING KAM KAM RLR RLR A-7 01/06/25 ISSUED FOR PERMITTING KAM KAM RLR RLR Digitally Sealed 01/06/2025 APPENDIX H – OPERATIONS & MAINTENANCE PLAN NSTAR ELECTRIC COMPANY D/B/A E VERSOURCE ENERGY OPERATION AND MAINTENANCE P LAN FOR STORMWATER BMPS WEST BARNSTABLE STATION EXPANSION PROJECT NO. 152841 R EVISION 3 JANUARY 6, 2025 CONTENTS 1.0 GENERAL OVERVIEW ................................................................................................. 1 1.1 Purpose and Goals ...................................................................................................... 1 1.2 Responsible Parties ..................................................................................................... 1 1.3 Maintenance Logs and Checklists ............................................................................... 1 1.4 Forms and Record Keeping ......................................................................................... 1 2.0 Training ...................................................................................................................... 1 3.0 Stormwater Management System ............................................................................ 2 3.1 Substation Yard Stone Section .................................................................................... 2 3.2 Vegetated Swales ........................................................................................................ 2 3.3 Riprap Outlet Protection ............................................................................................. 2 3.4 Underdrains ................................................................................................................ 2 3.5 Disposal ....................................................................................................................... 3 4.0 Long-Term Pollution Prevention Plan ....................................................................... 3 APPENDIX A – RECORDING KEEPING LOGS 1 Eversource Energy 1.0 GENERAL OVERVIEW Burns & McDonnell has prepared this Operation and Maintenance (“O&M”) Plan on behalf of NSTAR Electric Company d/b/a Eversource Energy for the post-construction stormwater management system located at the West Barnstable Station Expansion in the Town of Barnstable, Massachusetts. The O&M Plan is in accordance with the Massachusetts Stormwater Handbook and will be implemented upon completion of construction as outlined below. Any required post-construction stormwater management permits will be obtained and implemented by Eversource Energy. Operation and maintenance procedures made part of this plan shall be in addition to any operation and maintenance procedures already in place at the facility. 1.1 Purpose and Goals The purpose of this O&M Plan is to provide guidance for the implementation and documentation process of the facilities stormwater management system associated with the West Barnstable Station Expansion to help conform with the corresponding regulatory agency approvals and permits. The guidance provided herein is the minimum required. The primary goal is to inform all the property managers of how the system operates and what maintenance items are necessary to protect the downstream wetlands. The secondary goal is to provide a practical, efficient means of maintenance planning and record keeping to verify permit compliance. 1.2 Responsible Parties Eversource Energy is the owner of the stormwater system and will be responsible for implementing the O&M Plan. Name: Address: Phone #: Email: 1.3 Maintenance Logs and Checklists Eversource Energy will keep a record of all maintenance procedures performed, date of inspections, cleanings, etc. Copies of inspection reports and maintenance records shall be kept on-site. 1.4 Forms and Record Keeping Inspection and maintenance procedures shall be logged and recorded. Copies of the logs shall be kept on site. 2.0 Training Responsible operators, maintenance workers, and contractors will be trained with a basic description of the purpose and function of the on-site stormwater management system as well as safety protocols and procedures, with annual updates, to ensure that the workers tasked with maintaining the site do so in accordance with the 2 Eversource Energy approved permit conditions. All workers with maintenance duties will be adequately informed of their responsibilities. All sub-contractors will be informed of any special requirements or responsibilities. 3.0 Stormwater Management System The on-site stormwater management system has several components that perform various functions in conveying and treating stormwater runoff. Refer to the Site Plans for locations and details for each of the stormwater system components. Regular operation and maintenance are critical to the long-term success of the stormwater management system. The stormwater system components are: · Substation Yard Stone Section · Vegetated Swales · Riprap Outlet Protection 3.1 Substation Yard Stone Section The substation yard stone can become compacted and eroded over time. Inspect the yard section after every major storm for the first few months to ensure it is stabilized and functioning properly, and if necessary, take corrective action. Immediately address any areas of ponding, as ponding indicates clogging of the yard section. Clogging may be due to upland sediment erosion, excessive compaction of soils or low spots. As stone areas compact, scrape off the top layer to subgrade elevation and install a new layer of crushed stone surfacing at design elevation and pitch. After a few months of use, inspect the yard section at least twice per year. 3.2 Vegetated Swales Vegetated swales are vegetated open channels designed to provide stormwater conveyance with limited erosion. Within the first few months after construction, inspect the swales regularly to ensure that the vegetation is adequate and that there are no signs of gullying. After the first few months, these inspections should occur twice a year. Conditions to consider during the inspection include slope integrity, soil moisture, vegetative health, soil stability, soil compaction, soil erosion, ponding, and sediment accumulation. If discovered, repair any gullies and replace any dead vegetation. Additional maintenance includes mowing at least once a year, removing sediment and debris manually at least once a year, and re-seeding periodically to maintain dense growth. Grass height should remain under six inches but be no lower than three to four inches. 3.3 Riprap Outlet Protection Riprap outlet protection consists of riprap areas downstream of stormwater outlets designed to slow the velocity of stormwater and limit potential erosion. These areas should be inspected regularly, especially after large storm events (a storm equal to or greater than a 2-year, 24-hour storm). Any low spots in the riprap should be noted and repaired during these inspections. Additionally, any areas of erosion should be noted and addressed. 3.4 Underdrains Underdrains are in areas indicated on the Grading & Drainage Plan. Underdrains shall be inspected, checked for clogging, and cleaned at least twice per year through the access points and outlets. Remove any accumulated sediment and debris. 3 Eversource Energy 3.5 Disposal All sediment, debris, trash, etc. removed from the stormwater management system during operations and maintenance shall be disposed of properly and legally by a Massachusetts Licensed hauler. 4.0 Long-Term Pollution Prevention Plan Eversource Energy will employ good housekeeping measures to prevent pollution from the site. Specifically, Eversource Energy shall: · Perform routine inspections and maintenance duties per the Operations and Maintenance Plan. · Repair, replace, or restore and damaged, deteriorated, or eroded components of the stormwater management system. · Ensure that no illicit connections to the stormwater management system occur. · Prohibit the excessive use of chemicals on the site above the manufacturer’s recommendations. · Prohibit the storage of oil and chemicals outside of appropriate containers specifically designed for the storage of said materials. · Eversource Energy maintenance staff will be trained to inspect and maintain the stormwater system. APPENDIX A – RECORDING KEEPING LOGS INSPECTION AND MAINTENANCE LOG DATE OF INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU PERSON PERFORMING INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU SUBSTATION YARD SECTION: Inspect the yard section after every major storm for the first few months to ensure it is stabilized and functioning properly, and if necessary, take corrective action. Immediately address any areas of ponding, as ponding indicates clogging of the yard section. Clogging may be due to upland sediment erosion, excessive compaction of soils or low spots. As stone areas compact, scrape off the top layer to subgrade elevation and install a new layer of crushed stone surfacing at design elevation and pitch. After the first few months, these inspections should occur twice a year.  FIRST INSPECTION OF YEAR  SECOND INSPECTION OF YEAR  INSPECTION AFTER MAJOR STORM EVENT ARE THERE AREAS OF PONDING? ARE THERE AREAS OF EXCESSIVE COMPACTION? DOES THE YARD SECTION REQUIRE REGRADING? IS NEW STONE REQUIRED? METHOD OF REPAIR  YES  NO  YES  NO  YES  NO  YES  NO ADDITIONAL NOTES: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU INSPECTION AND MAINTENANCE LOG DATE OF INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU PERSON PERFORMING INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU VEGETATED SWALES: Inspect the vegetated swales every major storm for the first few months to ensure vegetation is adequate and there are no signs of gullying, and if necessary, take corrective action. After the first few months, these inspections should occur twice a year.  FIRST INSPECTION OF YEAR  SECOND INSPECTION OF YEAR  INSPECTION AFTER MAJOR STORM EVENT DEPTH OF SEDIMENT IS THE REMOVAL OF SEDIMENT REQUIRED? IS MOWING REQUIRED? IS RESEEDING REQUIRED? METHOD OF CLEANING  YES  NO  YES  NO  YES  NO ADDITIONAL NOTES: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU INSPECTION AND MAINTENANCE LOG DATE OF INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU PERSON PERFORMING INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU RIPRAP OUTLET PROTECTION: Inspect the riprap outlet protection after every major storm for the first few months to ensure it is stabilized and functioning properly, and if necessary, take corrective action. Any low spots in the riprap should be noted and repaired during these inspections. Additionally, any areas of erosion should be noted and addressed. After the first few months, these inspections should occur twice a year.  FIRST INSPECTION OF YEAR  SECOND INSPECTION OF YEAR  INSPECTION AFTER MAJOR STORM EVENT IS THE AREA STABILIZED? ARE THERE LOW SPOTS? ARE THERE AREAS OF EROSION? IS NEW STONE REQUIRED? METHOD OF REPAIR  YES NO  YES NO  YES NO  YES NO ADDITIONAL NOTES: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU INSPECTION AND MAINTENANCE LOG DATE OF INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU PERSON PERFORMING INSPECTION: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UNDERDRAINS: Underdrains shall be inspected, checked for clogging, and cleaned at least twice per year through the access points and outlets. Remove any accumulated sediment and debris.  FIRST INSPECTION OF YEAR  SECOND INSPECTION OF YEAR ARE THERE ANY SIGNS OF CLOGGING? IS CLEANING REQUIRED? ARE REPAIRS REQUIRED? METHOD OF REPAIR  YES NO  YES NO  YES NO ADDITIONAL NOTES: UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU Eversource Energy Revision History Log Revision Date Revised Reason for Revision Author Approved By APPENDIX I – MASSDEP STORMWATER CHECKLIST swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report A. Introduction Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key. A Stormwater Report must be submitted with the Notice of Intent permit application to document compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for the Stormwater Report (which should provide more substantive and detailed information) but is offered here as a tool to help the applicant organize their Stormwater Management documentation for their Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, the Stormwater Report must contain the engineering computations and supporting information set forth in Volume 3 of the Massachusetts Stormwater Handbook. The Stormwater Report must be prepared and certified by a Registered Professional Engineer (RPE) licensed in the Commonwealth. The Stormwater Report must include:  The Stormwater Checklist completed and stamped by a Registered Professional Engineer (see page 2) that certifies that the Stormwater Report contains all required submittals.1 This Checklist is to be used as the cover for the completed Stormwater Report.  Applicant/Project Name  Project Address  Name of Firm and Registered Professional Engineer that prepared the Report  Long-Term Pollution Prevention Plan required by Standards 4-6  Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82  Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads (LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 1 The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report, the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects, it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event, the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 2 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report B. Stormwater Checklist and Certification The following checklist is intended to serve as a guide for applicants as to the elements that ordinarily need to be addressed in a complete Stormwater Report. The checklist is also intended to provide conservation commissions and other reviewing authorities with a summary of the components necessary for a comprehensive Stormwater Report that addresses the ten Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. If it is determined that a specific item does not apply to the project under review, please note that the item is not applicable (N.A.) and provide the reasons for that determination. A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stormwater Report. Registered Professional Engineer’s Certification I have reviewed the Stormwater Report, including the soil evaluation, computations, Long-term Pollution Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long- term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement (if included) and the plans showing the stormwater management system, and have determined that they have been prepared in accordance with the requirements of the Stormwater Management Standards as further elaborated by the Massachusetts Stormwater Handbook. I have also determined that the information presented in the Stormwater Checklist is accurate and that the information presented in the Stormwater Report accurately reflects conditions at the site as of the date of this permit application. Registered Professional Engineer Block and Signature Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? New development Redevelopment Mix of New Development and Redevelopment X Digitally Sealed 01/06/2025 1/6/25 swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 3 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: No disturbance to any Wetland Resource Areas Site Design Practices (e.g. clustered development, reduced frontage setbacks) Reduced Impervious Area (Redevelopment Only) Minimizing disturbance to existing trees and shrubs LID Site Design Credit Requested: Credit 1 Credit 2 Credit 3 Use of “country drainage” versus curb and gutter conveyance and pipe Bioretention Cells (includes Rain Gardens) Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Treebox Filter Water Quality Swale Grass Channel Green Roof Other (describe): Standard 1: No New Untreated Discharges No new untreated discharges Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. X X Disconnected impervious, crushed stone yard section X X X swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 4 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 2: Peak Rate Attenuation Standard 2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. Standard 3: Recharge Soil Analysis provided. Required Recharge Volume calculation provided. Required Recharge volume reduced through use of the LID site Design Credits. Sizing the infiltration, BMPs is based on the following method: Check the method used. Static Simple Dynamic Dynamic Field1 Runoff from all impervious areas at the site discharging to the infiltration BMP. Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: Site is comprised solely of C and D soils and/or bedrock at the land surface M.G.L. c. 21E sites pursuant to 310 CMR 40.0000 Solid Waste Landfill pursuant to 310 CMR 19.000 Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. Calculations showing that the infiltration BMPs will drain in 72 hours are provided. Property includes a M.G.L. c. 21E site or a solid waste landfill and a mounding analysis is included. 1 80% TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. X X X X X X X X swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 3: Recharge (continued) The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding analysis is provided. Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. Standard 4: Water Quality The Long-Term Pollution Prevention Plan typically includes the following:  Good housekeeping practices;  Provisions for storing materials and waste products inside or under cover;  Vehicle washing controls;  Requirements for routine inspections and maintenance of stormwater BMPs;  Spill prevention and response plans;  Provisions for maintenance of lawns, gardens, and other landscaped areas;  Requirements for storage and use of fertilizers, herbicides, and pesticides;  Pet waste management provisions;  Provisions for operation and management of septic systems;  Provisions for solid waste management;  Snow disposal and plowing plans relative to Wetland Resource Areas;  Winter Road Salt and/or Sand Use and Storage restrictions;  Street sweeping schedules;  Provisions for prevention of illicit discharges to the stormwater management system;  Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL;  Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan;  List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. A Long-Term Pollution Prevention Plan is attached to Stormwater Report and is included as an attachment to the Wetlands Notice of Intent. Treatment BMPs subject to the 44% TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: is within the Zone II or Interim Wellhead Protection Area is near or to other critical areas is within soils with a rapid infiltration rate (greater than 2.4 inches per hour) involves runoff from land uses with higher potential pollutant loads. The Required Water Quality Volume is reduced through use of the LID site Design Credits. Calculations documenting that the treatment train meets the 80% TSS removal requirement and, if applicable, the 44% TSS removal pretreatment requirement, are provided. X X X swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 6 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 4: Water Quality (continued) The BMP is sized (and calculations provided) based on: The ½” or 1” Water Quality Volume or The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) The NPDES Multi-Sector General Permit covers the land use and the Stormwater Pollution Prevention Plan (SWPPP) has been included with the Stormwater Report. The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. The NPDES Multi-Sector General Permit does not cover the land use. LUHPPLs are located at the site and industry specific source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the long term Pollution Prevention Plan. All exposure has been eliminated. All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease (e.g. all parking lots with >1000 vehicle trips per day) and the treatment train includes an oil grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP has approved for stormwater discharges to or near that particular class of critical area. Critical areas and BMPs are identified in the Stormwater Report. X X swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: Limited Project Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff Bike Path and/or Foot Path Redevelopment Project Redevelopment portion of mix of new and redevelopment. Certain standards are not fully met (Standard No. 1, 8, 9, and 10 must always be fully met) and an explanation of why these standards are not met is contained in the Stormwater Report. The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a) complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information:  Narrative;  Construction Period Operation and Maintenance Plan;  Names of Persons or Entity Responsible for Plan Compliance;  Construction Period Pollution Prevention Measures;  Erosion and Sedimentation Control Plan Drawings;  Detail drawings and specifications for erosion control BMPs, including sizing calculations;  Vegetation Planning;  Site Development Plan;  Construction Sequencing Plan;  Sequencing of Erosion and Sedimentation Controls;  Operation and Maintenance of Erosion and Sedimentation Controls;  Inspection Schedule;  Maintenance Schedule;  Inspection and Maintenance Log Form. A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. X X X swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 8 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control (continued) The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. The project is not covered by a NPDES Construction General Permit. The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the Stormwater Report. The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. Standard 9: Operation and Maintenance Plan The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: Name of the stormwater management system owners; Party responsible for operation and maintenance; Schedule for implementation of routine and non-routine maintenance tasks; Plan showing the location of all stormwater BMPs maintenance access areas; Description and delineation of public safety features; Estimated operation and maintenance budget; and Operation and Maintenance Log Form. The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: A copy of the legal instrument (deed, homeowner’s association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; An Illicit Discharge Compliance Statement is attached; NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. X X X X X X X X APPENDIX J – ILLICIT DISCHARGE COMPLIANCE STATEMENT STANDARD 10: ILLICIT DISCHARGE COMPLIANCE STATEMENT Project Name: West Barnstable Station Expansion Owner: NSTAR Electric Company d/b/a Eversource Energy Location: Oak Street, Barnstable, Massachusetts Standard 10 states: All illicit discharges to the stormwater management system are prohibited. This is to verify: 1. Based on the information available there are no known or suspected illicit discharges to the stormwater management system at the West Barnstable Station Expansion located on Oak Street in Barnstable, Massachusetts as defined in the MassDEP Stormwater Handbook. 2. The design of the stormwater system includes no proposed illicit discharges. Responsible Party: NSTAR Electric Company d/b/a Eversource Energy By: Date: Name: Liz Pietrantuono Title: Project Director, Cape Cod Solution Program Telephone: 978-729-6019 1/6/2025