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Stormwater Narrative900 Route 146 Clifton Park, NY 12065 (P) 518.371.7621 (F) 518.371.9540 edpllp.com STORMWATER DESIGN REPORT 374 Glen Lake Road QUEENSBURY, NEW YORK 1. INTRODUCTION The owners of the existing residence, located at 374 Glen Lake Road in the Town of Queensbury, are proposing modifications to the existing residence and site. These modifications include an addition to the existing dwelling, a patio area and shoreline stabilization and access improvements. The existing site is approximately 0.65 acres and the proposed project will result in an additional 487 square feet of impervious area on the site. The total disturbance for the site is on the order of 0.20 acres and therefore the site does not require coverage under a NYSDEC SPDES permit and does not require post construction stormwater designed in accordance with the NYSDEC Stormwater Management Design Manual. The project site is also located outside of Lake George Park and therefore is not required to meet the stormwater management regulations of Section 147-11 of the Town of Queensbury Code. 2. EXISTING SITE CONDITIONS The existing site currently contains a small single-family residence, a detached garage, access driveway and lawn areas. The topography of the site is moderately slopes with with the majority of slopes ranging from 5 % to 15%. The existing site drainage is split between being directed to Glen Lake, to the neighboring property to the north and toward Glen Lake Road. The USDA Web Soil Survey specifies the soil types on the project site to be Hinckley cobbly sandy loam sand (HnC), which is a deep, excessively drained soil classified as hydrologic soil group “A”. A soil test pit in the area of the proposed septic system verified that the existing soils are coarse sand and gravel with cobbles to a depth of at least 68 inches below grade. 3. STORMWATER DESIGN The proposed project includes the construction of stone eave trenches and permeable patios in order to collect and infiltrate runoff from the proposed building roof and hardscape areas. In accordance with section 179-6-080 of the Town of Queensbury code the stormwater management system has been designed to limit the post-development runoff rates and volumes for the 25-year, 24-hour design storm event to less than the predevelopment runoff rates and volumes in order to prevent impacts to the downstream drainage corridors. HydroCAD stormwater modeling software was used to analyze the existing and proposed site conditions with the results summarized in the following table. 2 900 Route 146 Clifton Park, NY 12065(P) 518.371.7621 (F) 518.371.9540 edpllp.com374 Glen Lake Road Stormwater Design Report Table 1: 25-Year (4.37 in) Design Storm, Runoff Rates and Volumes Design Point Peak Runoff Rate (cfs) Runoff Volume (ac-ft) Predevelopment Post-Development Predevelopment Post-Development 1 0.04 0.00 0.003 0.001 2 0.00 0.00 0.001 0.001 3 0.32 0.32 0.014 0.014 4. SUMMARY The modifications to the proposed site will result in an increase in the amount of impervious area on the project site. To accommodate the existing impervious areas permeable paver patios and eave trenches will be installed. In conclusion the proposed site modifications will not result in any increases in runoff rates and volumes from the site and will not result in any flooding of downstream properties. Respectively Submitted, Brandon M. Ferguson, P.E. Environmental Design Partnership, LLP 3 900 Route 146 Clifton Park, NY 12065(P) 518.371.7621 (F) 518.371.9540 edpllp.com374 Glen Lake Road Stormwater Design Report Appendix A: Predevelopment Stormwater Modeling 1S 2S 3S 1 GLEN LAKE 2 NORTH 3 GLEN LAKE ROAD Routing Diagram for PRE-DEVELOPMENT Prepared by Environmental Design Partnership, Printed 12/20/2023 HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link PRE-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 2HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 25 YEAR Type II 24-hr Default 24.00 1 4.37 2 PRE-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 3HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.278 39 >75% Grass cover, Good, HSG A (1S, 2S, 3S) 0.003 98 DECK (1S) 0.051 98 EX DRIVE (3S) 0.002 98 RAMP (1S) 0.032 98 ROOF (1S, 2S, 3S) 0.366 53 TOTAL AREA PRE-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 4HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.278 HSG A 1S, 2S, 3S 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.088 Other 1S, 2S, 3S 0.366 TOTAL AREA PRE-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 5HydroCAD® 10.20-3g s/n 00476 © 2023 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 0.278 0.000 0.000 0.000 0.000 0.278 >75% Grass cover, Good 1S, 2S, 3S 0.000 0.000 0.000 0.000 0.003 0.003 DECK 1S 0.000 0.000 0.000 0.000 0.051 0.051 EX DRIVE 3S 0.000 0.000 0.000 0.000 0.002 0.002 RAMP 1S 0.000 0.000 0.000 0.000 0.032 0.032 ROOF 1S, 2S, 3S 0.278 0.000 0.000 0.000 0.088 0.366 TOTAL AREA Type II 24-hr 25 YEAR Rainfall=4.37"PRE-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 6HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=6,170 sf 13.05% Impervious Runoff Depth>0.27"Subcatchment 1S: Flow Length=65' Slope=0.1700 '/' Tc=6.0 min CN=47 Runoff=0.04 cfs 0.003 af Runoff Area=4,390 sf 6.83% Impervious Runoff Depth>0.15"Subcatchment 2S: Flow Length=60' Slope=0.0500 '/' Tc=7.4 min CN=43 Runoff=0.00 cfs 0.001 af Runoff Area=5,375 sf 50.60% Impervious Runoff Depth>1.37"Subcatchment 3S: Flow Length=100' Slope=0.0350 '/' Tc=6.0 min CN=69 Runoff=0.32 cfs 0.014 af Inflow=0.04 cfs 0.003 afLink 1: GLEN LAKE Primary=0.04 cfs 0.003 af Inflow=0.00 cfs 0.001 afLink 2: NORTH Primary=0.00 cfs 0.001 af Inflow=0.32 cfs 0.014 afLink 3: GLEN LAKE ROAD Primary=0.32 cfs 0.014 af Total Runoff Area = 0.366 ac Runoff Volume = 0.019 af Average Runoff Depth = 0.61" 76.00% Pervious = 0.278 ac 24.00% Impervious = 0.088 ac Type II 24-hr 25 YEAR Rainfall=4.37"PRE-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 7HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: Runoff = 0.04 cfs @ 12.02 hrs, Volume= 0.003 af, Depth> 0.27" Routed to Link 1 : GLEN LAKE Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Area (sf) CN Description 5,365 39 >75% Grass cover, Good, HSG A * 590 98 ROOF * 130 98 DECK * 85 98 RAMP 6,170 47 Weighted Average 5,365 86.95% Pervious Area 805 13.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 65 0.1700 0.22 Sheet Flow, Grass: Dense n= 0.240 P2= 2.54" 4.8 65 Total, Increased to minimum Tc = 6.0 min Summary for Subcatchment 2S: Runoff = 0.00 cfs @ 12.10 hrs, Volume= 0.001 af, Depth> 0.15" Routed to Link 2 : NORTH Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Area (sf) CN Description 4,090 39 >75% Grass cover, Good, HSG A * 300 98 ROOF 4,390 43 Weighted Average 4,090 93.17% Pervious Area 300 6.83% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.4 60 0.0500 0.14 Sheet Flow, Grass: Dense n= 0.240 P2= 2.54" Summary for Subcatchment 3S: Runoff = 0.32 cfs @ 11.98 hrs, Volume= 0.014 af, Depth> 1.37" Routed to Link 3 : GLEN LAKE ROAD Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Type II 24-hr 25 YEAR Rainfall=4.37"PRE-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 8HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Area (sf) CN Description * 500 98 ROOF * 2,220 98 EX DRIVE 2,655 39 >75% Grass cover, Good, HSG A 5,375 69 Weighted Average 2,655 49.40% Pervious Area 2,720 50.60% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.1 100 0.0350 1.53 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.54" 1.1 100 Total, Increased to minimum Tc = 6.0 min Summary for Link 1: GLEN LAKE Inflow Area = 0.142 ac, 13.05% Impervious, Inflow Depth > 0.27" for 25 YEAR event Inflow = 0.04 cfs @ 12.02 hrs, Volume= 0.003 af Primary = 0.04 cfs @ 12.02 hrs, Volume= 0.003 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 2: NORTH Inflow Area = 0.101 ac, 6.83% Impervious, Inflow Depth > 0.15" for 25 YEAR event Inflow = 0.00 cfs @ 12.10 hrs, Volume= 0.001 af Primary = 0.00 cfs @ 12.10 hrs, Volume= 0.001 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 3: GLEN LAKE ROAD Inflow Area = 0.123 ac, 50.60% Impervious, Inflow Depth > 1.37" for 25 YEAR event Inflow = 0.32 cfs @ 11.98 hrs, Volume= 0.014 af Primary = 0.32 cfs @ 11.98 hrs, Volume= 0.014 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs 4 900 Route 146 Clifton Park, NY 12065(P) 518.371.7621 (F) 518.371.9540 edpllp.com374 Glen Lake Road Stormwater Design Report Appendix B: Post-development Stormwater Modeling 1A 1B 1C 2A 3A 5S R1 LAWN R2 LAWN 1P PAVERS2P EAVE TRENCH 3P EAVE TRENCH 1 GLEN LAKE 2 NORTH 3 GLEN LAKE ROAD Routing Diagram for POST-DEVELOPMENT Prepared by Environmental Design Partnership, Printed 12/20/2023 HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 2HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 25 YEAR Type II 24-hr Default 24.00 1 4.37 2 POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 3HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.263 39 >75% Grass cover, Good, HSG A (1A, 2A, 3A) 0.051 98 EX DRIVE (3A) 0.013 98 PATIO (1A, 1C, 3A) 0.039 98 ROOF (1B, 1C, 3A, 5S) 0.366 56 TOTAL AREA POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 4HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.263 HSG A 1A, 2A, 3A 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.103 Other 1A, 1B, 1C, 3A, 5S 0.366 TOTAL AREA POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 5HydroCAD® 10.20-3g s/n 00476 © 2023 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 0.263 0.000 0.000 0.000 0.000 0.263 >75% Grass cover, Good 1A, 2A, 3A 0.000 0.000 0.000 0.000 0.051 0.051 EX DRIVE 3A 0.000 0.000 0.000 0.000 0.013 0.013 PATIO 1A, 1C, 3A 0.000 0.000 0.000 0.000 0.039 0.039 ROOF 1B, 1C, 3A, 5S 0.263 0.000 0.000 0.000 0.103 0.366 TOTAL AREA Type II 24-hr 25 YEAR Rainfall=4.37"POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 6HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=5,170 sf 1.35% Impervious Runoff Depth>0.08"Subcatchment 1A: Flow Length=65' Slope=0.1700 '/' Tc=6.0 min CN=40 Runoff=0.00 cfs 0.001 af Runoff Area=485 sf 100.00% Impervious Runoff Depth>3.80"Subcatchment 1B: Flow Length=15' Slope=0.5000 '/' Tc=6.0 min CN=98 Runoff=0.07 cfs 0.004 af Runoff Area=731 sf 100.00% Impervious Runoff Depth>3.80"Subcatchment 1C: Flow Length=15' Slope=0.5000 '/' Tc=6.0 min CN=98 Runoff=0.10 cfs 0.005 af Runoff Area=3,940 sf 0.00% Impervious Runoff Depth>0.06"Subcatchment 2A: Flow Length=60' Slope=0.0500 '/' Tc=7.4 min CN=39 Runoff=0.00 cfs 0.000 af Runoff Area=5,140 sf 52.63% Impervious Runoff Depth>1.44"Subcatchment 3A: Flow Length=100' Slope=0.0350 '/' Tc=6.0 min CN=70 Runoff=0.32 cfs 0.014 af Runoff Area=485 sf 100.00% Impervious Runoff Depth>3.80"Subcatchment 5S: Flow Length=15' Slope=0.5000 '/' Tc=6.0 min CN=98 Runoff=0.07 cfs 0.004 af Avg. Flow Depth=0.00' Max Vel=0.00 fps Inflow=0.00 cfs 0.000 afReach R1: LAWN n=0.240 L=40.0' S=0.1500 '/' Capacity=2.42 cfs Outflow=0.00 cfs 0.000 af Avg. Flow Depth=0.01' Max Vel=0.05 fps Inflow=0.01 cfs 0.000 afReach R2: LAWN n=0.240 L=60.0' S=0.0500 '/' Capacity=1.40 cfs Outflow=0.00 cfs 0.000 af Peak Elev=406.26' Storage=2 cf Inflow=0.10 cfs 0.005 afPond 1P: PAVERS Outflow=0.10 cfs 0.005 af Peak Elev=407.64' Storage=48 cf Inflow=0.07 cfs 0.004 afPond 2P: EAVE TRENCH Discarded=0.01 cfs 0.004 af Primary=0.00 cfs 0.000 af Outflow=0.01 cfs 0.004 af Peak Elev=408.00' Storage=48 cf Inflow=0.07 cfs 0.004 afPond 3P: EAVE TRENCH Discarded=0.01 cfs 0.003 af Primary=0.01 cfs 0.000 af Outflow=0.02 cfs 0.004 af Inflow=0.00 cfs 0.001 afLink 1: GLEN LAKE Primary=0.00 cfs 0.001 af Inflow=0.00 cfs 0.001 afLink 2: NORTH Primary=0.00 cfs 0.001 af Inflow=0.32 cfs 0.014 afLink 3: GLEN LAKE ROAD Primary=0.32 cfs 0.014 af Total Runoff Area = 0.366 ac Runoff Volume = 0.028 af Average Runoff Depth = 0.91" 71.94% Pervious = 0.263 ac 28.06% Impervious = 0.103 ac Type II 24-hr 25 YEAR Rainfall=4.37"POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 7HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 1A: Runoff = 0.00 cfs @ 13.34 hrs, Volume= 0.001 af, Depth> 0.08" Routed to Link 1 : GLEN LAKE Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Area (sf) CN Description 5,100 39 >75% Grass cover, Good, HSG A * 70 98 PATIO 5,170 40 Weighted Average 5,100 98.65% Pervious Area 70 1.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 65 0.1700 0.22 Sheet Flow, Grass: Dense n= 0.240 P2= 2.54" 4.8 65 Total, Increased to minimum Tc = 6.0 min Summary for Subcatchment 1B: Runoff = 0.07 cfs @ 11.96 hrs, Volume= 0.004 af, Depth> 3.80" Routed to Pond 2P : EAVE TRENCH Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Area (sf) CN Description * 485 98 ROOF 485 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.1 15 0.5000 3.04 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.54" 0.1 15 Total, Increased to minimum Tc = 6.0 min Summary for Subcatchment 1C: Runoff = 0.10 cfs @ 11.96 hrs, Volume= 0.005 af, Depth> 3.80" Routed to Pond 1P : PAVERS Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Type II 24-hr 25 YEAR Rainfall=4.37"POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 8HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Area (sf) CN Description * 314 98 ROOF * 417 98 PATIO 731 98 Weighted Average 731 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.1 15 0.5000 3.04 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.54" 0.1 15 Total, Increased to minimum Tc = 6.0 min Summary for Subcatchment 2A: Runoff = 0.00 cfs @ 14.94 hrs, Volume= 0.000 af, Depth> 0.06" Routed to Link 2 : NORTH Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Area (sf) CN Description 3,940 39 >75% Grass cover, Good, HSG A 3,940 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.4 60 0.0500 0.14 Sheet Flow, Grass: Dense n= 0.240 P2= 2.54" Summary for Subcatchment 3A: Runoff = 0.32 cfs @ 11.98 hrs, Volume= 0.014 af, Depth> 1.44" Routed to Link 3 : GLEN LAKE ROAD Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Area (sf) CN Description * 425 98 ROOF * 60 98 PATIO * 2,220 98 EX DRIVE 2,435 39 >75% Grass cover, Good, HSG A 5,140 70 Weighted Average 2,435 47.37% Pervious Area 2,705 52.63% Impervious Area Type II 24-hr 25 YEAR Rainfall=4.37"POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 9HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.1 100 0.0350 1.53 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.54" 1.1 100 Total, Increased to minimum Tc = 6.0 min Summary for Subcatchment 5S: Runoff = 0.07 cfs @ 11.96 hrs, Volume= 0.004 af, Depth> 3.80" Routed to Pond 3P : EAVE TRENCH Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37" Area (sf) CN Description * 485 98 ROOF 485 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.1 15 0.5000 3.04 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.54" 0.1 15 Total, Increased to minimum Tc = 6.0 min Summary for Reach R1: LAWN Inflow Area = 0.011 ac,100.00% Impervious, Inflow Depth = 0.00" for 25 YEAR event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to Link 1 : GLEN LAKE Routing by Stor-Ind+Trans method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Max. Velocity= 0.00 fps, Min. Travel Time= 0.0 min Avg. Velocity = 0.00 fps, Avg. Travel Time= 0.0 min Peak Storage= 0 cf @ 5.00 hrs Average Depth at Peak Storage= 0.00' Bank-Full Depth= 0.25' Flow Area= 3.3 sf, Capacity= 2.42 cfs 20.00' x 0.25' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 40.0' Slope= 0.1500 '/' Inlet Invert= 408.00', Outlet Invert= 402.00' ‡ Type II 24-hr 25 YEAR Rainfall=4.37"POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 10HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Summary for Reach R2: LAWN Inflow Area = 0.011 ac,100.00% Impervious, Inflow Depth = 0.06" for 25 YEAR event Inflow = 0.01 cfs @ 12.12 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 12.52 hrs, Volume= 0.000 af, Atten= 78%, Lag= 23.5 min Routed to Link 2 : NORTH Routing by Stor-Ind+Trans method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Max. Velocity= 0.05 fps, Min. Travel Time= 18.9 min Avg. Velocity = 0.02 fps, Avg. Travel Time= 42.6 min Peak Storage= 2 cf @ 12.20 hrs Average Depth at Peak Storage= 0.01' , Surface Width= 4.20' Bank-Full Depth= 0.25' Flow Area= 3.3 sf, Capacity= 1.40 cfs 20.00' x 0.25' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 60.0' Slope= 0.0500 '/' Inlet Invert= 408.00', Outlet Invert= 405.00' ‡ Summary for Pond 1P: PAVERS Inflow Area = 0.017 ac,100.00% Impervious, Inflow Depth > 3.80" for 25 YEAR event Inflow = 0.10 cfs @ 11.96 hrs, Volume= 0.005 af Outflow = 0.10 cfs @ 11.97 hrs, Volume= 0.005 af, Atten= 1%, Lag= 0.4 min Discarded = 0.10 cfs @ 11.97 hrs, Volume= 0.005 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 406.26' @ 11.97 hrs Surf.Area= 475 sf Storage= 2 cf Plug-Flow detention time= 0.3 min calculated for 0.005 af (100% of inflow) Center-of-Mass det. time= 0.3 min ( 731.1 - 730.8 ) Volume Invert Avail.Storage Storage Description #1 406.25' 190 cf Custom Stage Data (Prismatic) Listed below (Recalc) 475 cf Overall x 40.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 406.25 475 0 0 407.25 475 475 475 Device Routing Invert Outlet Devices #1 Discarded 406.25'10.000 in/hr Exfiltration over Surface area Type II 24-hr 25 YEAR Rainfall=4.37"POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 11HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Discarded OutFlow Max=0.11 cfs @ 11.97 hrs HW=406.26' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.11 cfs) Summary for Pond 2P: EAVE TRENCH Inflow Area = 0.011 ac,100.00% Impervious, Inflow Depth > 3.80" for 25 YEAR event Inflow = 0.07 cfs @ 11.96 hrs, Volume= 0.004 af Outflow = 0.01 cfs @ 11.65 hrs, Volume= 0.004 af, Atten= 85%, Lag= 0.0 min Discarded = 0.01 cfs @ 11.65 hrs, Volume= 0.004 af Primary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Routed to Reach R1 : LAWN Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 407.64' @ 12.18 hrs Surf.Area= 45 sf Storage= 48 cf Plug-Flow detention time= 25.8 min calculated for 0.004 af (100% of inflow) Center-of-Mass det. time= 25.6 min ( 756.4 - 730.8 ) Volume Invert Avail.Storage Storage Description #1 405.00' 54 cf Custom Stage Data (Prismatic) Listed below (Recalc) 135 cf Overall x 40.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 405.00 45 0 0 408.00 45 135 135 Device Routing Invert Outlet Devices #1 Discarded 405.00'10.000 in/hr Exfiltration over Surface area #2 Primary 408.00'20.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Discarded OutFlow Max=0.01 cfs @ 11.65 hrs HW=405.04' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 5.00 hrs HW=405.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 3P: EAVE TRENCH Inflow Area = 0.011 ac,100.00% Impervious, Inflow Depth > 3.80" for 25 YEAR event Inflow = 0.07 cfs @ 11.96 hrs, Volume= 0.004 af Outflow = 0.02 cfs @ 12.12 hrs, Volume= 0.004 af, Atten= 76%, Lag= 9.7 min Discarded = 0.01 cfs @ 11.65 hrs, Volume= 0.003 af Primary = 0.01 cfs @ 12.12 hrs, Volume= 0.000 af Routed to Reach R2 : LAWN Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25 YEAR Rainfall=4.37"POST-DEVELOPMENT Printed 12/20/2023Prepared by Environmental Design Partnership Page 12HydroCAD® 10.20-3g s/n 00476 © 2023 HydroCAD Software Solutions LLC Peak Elev= 408.00' @ 12.10 hrs Surf.Area= 40 sf Storage= 48 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 29.3 min ( 760.1 - 730.8 ) Volume Invert Avail.Storage Storage Description #1 405.00' 48 cf Custom Stage Data (Prismatic) Listed below (Recalc) 120 cf Overall x 40.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 405.00 40 0 0 408.00 40 120 120 Device Routing Invert Outlet Devices #1 Discarded 405.00'10.000 in/hr Exfiltration over Surface area #2 Primary 408.00'20.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Discarded OutFlow Max=0.01 cfs @ 11.65 hrs HW=405.05' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 12.12 hrs HW=408.00' (Free Discharge) 2=Broad-Crested Rectangular Weir (Weir Controls 0.00 cfs @ 0.07 fps) Summary for Link 1: GLEN LAKE Inflow Area = 0.130 ac, 9.81% Impervious, Inflow Depth > 0.08" for 25 YEAR event Inflow = 0.00 cfs @ 13.34 hrs, Volume= 0.001 af Primary = 0.00 cfs @ 13.34 hrs, Volume= 0.001 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 2: NORTH Inflow Area = 0.102 ac, 10.96% Impervious, Inflow Depth > 0.06" for 25 YEAR event Inflow = 0.00 cfs @ 12.52 hrs, Volume= 0.001 af Primary = 0.00 cfs @ 12.52 hrs, Volume= 0.001 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 3: GLEN LAKE ROAD Inflow Area = 0.118 ac, 52.63% Impervious, Inflow Depth > 1.44" for 25 YEAR event Inflow = 0.32 cfs @ 11.98 hrs, Volume= 0.014 af Primary = 0.32 cfs @ 11.98 hrs, Volume= 0.014 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs