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Home My WebLink AboutCC - Storm Drain Report STORM DRAINAGE REPORT AND CALCULATIONS FOR WINDROW SUBDIVISION NO. 1 MERIDIAN, IDAHO \o i PREPARED BY: 16970 CORINNE M GRAHAM, PE cos�g �P,o�P�. December 20, 2023 OF1 ��tiNE M.GAP Csw C 1N/I L S ITE W O R K S PO BOX 6059 BOISE, ID 83707 (208) 946-3874 cgraham@cswengineering.com INTRODUCTION The existing 17.61-acre site for the proposed Windrow Subdivision No. 1 is currently agricultural row crop ground.The proposed development includes 57 single family residential lots, 10 landscape common lots, and associated public streets, storm drainage, landscaping, and utilities. HISTORIC DRAINAGE The existing project site sits northeast of the intersection of W.Amity Road and S. Linder Road in Meridian.The site is bisected from southwest to northeast by the Calkins Lateral, which is also the high point along the property. Surficial soils are comprised of silt and silty sands. At depths of 2-6 feet, free draining coarse sand was encountered during geotechnical exploration. Groundwater was not encountered at depths up to 11 feet. Because of the presence of free draining materials and the depth to groundwater, the site is suitable for the use of infiltration facilities. PROPOSED DRAINAGE The storm drainage calculations and design for the proposed improvements are intended to meet the requirements of ACHD's storm water policy. Storm water facilities are designed to store and treat runoff from a 100-year storm event and to pretreat the water quality volume defined as the 801" percentile storm event. Storm water runoff from 50' behind the sidewalk, including residential driveways, will be conveyed to the public stormwater system to be owned and maintained by ACHD. Remaining lot drainage will be contained within individual lots. Stormwater runoff from the public streets is conveyed via curb and gutter to drain inlets within the roadway then piped to one of six underground seepage beds where it is treated, stored, and finally infiltrated.A sand and grease trap will be installed to provide pre-treatment for the water quality event. Runoff from Amity Road will be conveyed to a borrow ditch and sand windows along the street frontage. APPENDICES • Drainage Basin Map • Storm Drainage Calculations • Project Geotechnical Report a� EP 1 III �I I I 00 I I , BASIN #6 BASIN #5 I I I I I I I I I I I TEMP BASIN #7A TEMP BASIN #713 BASIN #5 ism Sim ism ME ism mm ism min min mis Imm min , I I BASIN � ° BASIN #2 ♦� _ ow BASIN #4 I - - JBASIN #1 I 1SM 1SM ME! 1010 EAGLE ROAD #1 A ' I EAGLE ROAD #1 B — — < — — < — — < — — < — < — — < — — < — — < — < — — < — — < — — < -- — < < — — < — < — — < -- — < — — < — — < — — < < — EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP EP N 0 30 60 120 180 WINDROW SUBDIVISION NO . 1 � IW o Rs !a DRAINAGE BASIN MAP SCALE: 1" = 60' PO BOX 6059 BOISE, ID 83707 Ph: (208) 946-3874 cgraham@cswengineering.com Prepared By: Corinne Graham, PE CSW December 20, 2023 C I V I L S I T E Windrow Subdivision No. 1 Storm Drainage Calculations C Values Impervious=0.90 Landscape=0.20 ACHD ACHD ACHD ACHD ACHD ACHD ACHD Temp ACHD Temp Eagle Eagle Basin#1 Basin#2 Basin#3 Basin#4 Basin#5 Basin#6 Basin#7A Basin#7B Road#1A Road#1B Total Area (SF) 22960 125787 92247 61175 51741 110412 7854 4395 65700 47124 Roadway Area (SF) 10651 30499 21049 13281 14101 24724 1760 1760 15621 11082 Sidewalk Area (SF) 1995 8801 6465 4580 5341 7489 657 661 9020 9473 House/Driveway Area (SF) 0 24636 13430 25300 12916 43012 3200 0 0 0 Landscape Area (SF) 10314 61851 51303 18014 19383 35187 2237 1974 41059 26569 C Value: 0.59 0.56 1 0.51 1 0.69 0.64 0.68 0.70 1 0.59 1 0.46 0.51 Catch Basin Calculations CB#1A CB#113 CB#2A CB#213 CB#3A CB#313 CB MA CB#413 Total Area (SF) 11116 11844 78989 46798 29500 62747 34877 26298 Roadway Area (SF) 5288 5363 15132 15367 6239 14809 6662 6620 Sidewalk Area (SF) 977 1018 5008 3770 2130 4295 2475 2105 House/Driveway Area (SF) 0 0 8300 16336 12350 1080 15700 9600 Landscape Area (SF) 4851 5463 50549 11325 8781 42563 10040 7973 C Value: 0.59 0.58 0.45 0.73 0.69 0.43 0.70 0.69 Prepared By: Corinne Graham, PE Csw December 20, 2023 C I V I L S I T E Catch Basin Calculations CB#5A CB#5B CB#6A CB#6B Total Area (SF) 19665 32077 54363 56050 Roadway Area (SF) 6863 7238 12200 12524 Sidewalk Area (SF) 2239 2709 3629 3860 House/Driveway Area (SF) 0 12916 19277 23735 Landscape Area (SF) 10563 9214 19257 15931 C Value: 0.52 0.70 0.65 0.70 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 10,651 1,995 10,314 Acres 0.53 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.59 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(OPeak) OPeA 0.80 0.80 cfs Urban neighborhoods 0.50-0.70 Residential 50 10 Calculate total runoff vol V for sizing rims storage) V 1,067 1,067 ft Single Family 0.60-0.75 ( )( g primary g ) Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 378 378 fY Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0. Playgrounds 0.20-0.0-0.35 5 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 107 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 960 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 1,067 1,067 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#1 2 Enter number of Seepage Beds(25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.59 Link to: QV — QV TR55 5 Area A(Acres) 0.53 acres 6 Approved discharge rate(if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? Yes V 1,067 1,067 ft' 0%Sediment 8 Set Total Design Width of All Drain Rock W 8.0 ft 9 Set Total Design Depth of All Drain Rock D 6.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe(Pert 1800) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 3600),READ if Q100>3.3 cfs 12 in 14 Calculate Total Storage per Foot Spf 25.2 ft3/ft 15 Calculate Design Length L 42 42 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 42 42.0 ft 17 Variable Infiltration Window W SWW 8.0 8.0 ft 18 Time to Drain 4.3 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 42 42 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers W Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:36 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 30,499 8,801 24,636 61,851 Acres 2.89 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.56 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(OPeak) OPeA 4.14 4.14 cfs Urban neighborhoods 0.50-0.70 Residential 50 10 Calculate total runoff vol V for sizing rims storage) V 5,547 5,547 ft Single Family 0.60-0.75 ( )( g primary g ) Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 1,964 1,964 fY Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Foreba V 555 ft' Y concrete 0.95 Primary Treatment/StorageBasin V 4,992 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor See BMP 20 Tab V 5,547 5,547 ft' Gravel 0.75 ( ) Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#2 2 Enter number of Seepage Beds(25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.56 Link to: QV — QV TR55 5 Area A(Acres) 2.89 acres 6 Approved discharge rate(if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? Yes V 5,547 5,547 ft' 0%Sediment 8 Set Total Design Width of All Drain Rock W 15.0 ft 9 Set Total Design Depth of All Drain Rock D 8.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe(Pert 1800) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 3600),READ if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 58.2 58.2 ft3/ft 15 Calculate Design Length L 95 95 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 95 95.0 ft 17 Variable Infiltration Window W SWW 15.0 15.0 ft 18 Time to Drain 5.3 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 95 95 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers W Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:36 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#3 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 21,049 6,465 13,430 51,303 Acres 2.12 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.51 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(OPeak) OPeA 2.79 2.79 cfs Urban neighborhoods 0.50-0.70 Residential 50 10 Calculate total runoff vol V for sizing rims storage) V 3,738 3,738 ft Single Family 0.60-0.75 ( )( g primary g ) Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 1,324 1,324 W Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0.20-0.25 Playgrounds 0. 0-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 374 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 3,364 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 3,738 3,738 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#3 2 Enter number of Seepage Beds(25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.51 Link to: QV — QV TR55 5 Area A(Acres) 2.12 acres 6 Approved discharge rate(if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? Yes V 3,738 3,738 ft' 0%Sediment 8 Set Total Design Width of All Drain Rock W 15.0 ft 9 Set Total Design Depth of All Drain Rock D 8.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe(Pert 1800) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 3600),READ if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 58.2 58.2 ft3/ft 15 Calculate Design Length L 64 64 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 64 64.0 ft 17 Variable Infiltration Window W SWW 15.0 15.0 ft 18 Time to Drain 5.3 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 64 64 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers W Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:36 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#4 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 13,281 4,580 25,300 18,014 Acres 1.40 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.69 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) Qp-k 2.51 2.51 cfs Urban neighborhoods 0.50-0.70 Residential 50 10 Calculate total runoff vol V for sizing rims storage) V 3,368 3,368 ft Single Family 0.60-0.75 ( )( g primary g ) Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 1,193 1,193 W Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0.20-0.25 Playgrounds 0. 0-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 337 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 3,031 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 3,368 3,368 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#4 2 Enter number of Seepage Beds(25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.69 Link to: QV — QV TR55 5 Area A(Acres) 1.40 acres 6 Approved discharge rate(if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? Yes V 3,368 3,368 ft' 0%Sediment 8 Set Total Design Width of All Drain Rock W 12.0 ft 9 Set Total Design Depth of All Drain Rock D 8.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe(Pert 1800) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 3600),READ if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 46.6 46.6 ft3/ft 15 Calculate Design Length L 72 72 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 72 72.0 ft 17 Variable Infiltration Window W SWW 12.0 12.0 ft 18 Time to Drain 57 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 72 72 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers W Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:36 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#5 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 14,101 5,341 12,916 19,383 Acres 1.19 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.64 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) peak 1.95 1. 55 cfs Urban neighborhoods 0.50-0.70 Residential 50 10 Calculate total runoff vol V for sizing rims storage) V 2,618 2,618 ft Single Family 0.60-0.75 ( )( g primary g ) Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 927 927 W Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0. Playgrounds 0.20-0.0-0.35 5 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 262 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 2,356 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 2,618 2,618 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#5 2 Enter number of Seepage Beds(25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.64 Link to: QV — QV TR55 5 Area A(Acres) 1.19 acres 6 Approved discharge rate(if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? Yes V 2,618 2,618 ft' 0%Sediment 8 Set Total Design Width of All Drain Rock W 12.0 ft 9 Set Total Design Depth of All Drain Rock D 8.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe(Pert 1800) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 3600),READ if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 46.6 46.6 ft3/ft 15 Calculate Design Length L 56 56 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 56 56.0 ft 17 Variable Infiltration Window W SWW 12.0 12.0 ft 18 Time to Drain 5.3 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 56 56 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers W Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:36 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#6 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 24,724 7,489 43,012 35,187 Acres 2.53 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.68 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) peak 4.43 4.43 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(for sizing primary storage) V 5,930 5,930 ft Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 2,100 7100 W Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 593 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 5,337 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 5,930 5,930 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Basin#6 2 Enter number of Seepage Beds(25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.68 Link to: QV — QV TR55 5 Area A(Acres) 2.53 acres 6 Approved discharge rate(if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? Yes V 5,930 5,930 ft' 0%Sediment 8 Set Total Design Width of All Drain Rock W 12.0 ft 9 Set Total Design Depth of All Drain Rock D 11.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe(Pert 1800) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 3600),READ if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 61.0 61.0 ft3/ft 15 Calculate Design Length L 97 97 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 97 97.0 ft 17 Variable Infiltration Window W SWW 12.0 12.0 ft 18 Time to Drain 6.9 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 97 97 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers W Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:36 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Temp Basin#7A 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 1,760 657 3,200 2,237 Acres 0.18 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.70 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) QpeA 0.33 0.33 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(for sizing primary storage) V 437 437 ft Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, lss 1s5 W Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 44 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 393 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 437 437 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Bioswales & Borrow Ditches NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name ACHD Temp Basin#7A 2 Enter number of Bioswales/Borrow Ditches(25 max) 1 3 Design Storm 100 Weighted Runoff Coefficient C 0.70 Link to: LQv 4 Area A(Acres) 0.18 acres Q,V TRSS Approved discharge rate for the given storm(if applicable) 0.00 cfs 5 Design Vol With 0%Sed for Swales V 437 436.58 ft' 6 Length of Swale 30 ft 7 Infiltration Window?(Note:infiltration required if Longitudinal Slope<1%) Design Infiltration Rate 8.00 in/hr 8 Infiltration Window Width 4.00 ft 9 Set Swale Bottom Width b 4.00 ft 10 Set Swale Top Width 16.00 ft 11 Set Swale Depth y 1.50 ft 12 Swale Side Slopes H:1 Sxs 4.00 13 Calculate cross-sectional area Axs 15.00 15.00 ftz Axs=Y zz+by 14 Total Swale Capacity Without Driveways 450 450.00 ft' 15 Does it Have Capacity? OK 16 Time to Drain 5.5 5.46 hr 90%volume in 48-hours minimum OK Check Borrow Ditch Infiltration Windows 17 Enter Infiltration Window Length 30.00 ft 18 Enter Infiltration Window Width 4 If 19 Time to Drain 6.1 6.1 hr 90%volume in 48-hours minimum OK C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:40 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Temp Basin#713 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 1,760 661 0 1,974 Acres 0.10 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.59 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) QpeA 0.15 0.15 cfs Urban neighborhoods 0.50-0.70 Residential 50 10 Calculate total runoff vol V for sizing rims storage) V 204 204 ft Single Family 0.60-0.75 ( )( g primary g ) Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 72 72 fY Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 20 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 184 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 204 204 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Bioswales & Borrow Ditches NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name ACHD Temp Basin#7B 2 Enter number of Bioswales/Borrow Ditches(25 max) 1 3 Design Storm 100 Weighted Runoff Coefficient C 0.59 Link to: LQv 4 Area A(Acres) 0.10 acres Q,V TRSS Approved discharge rate for the given storm(if applicable) 0.00 cfs 5 Design Vol With 0%Sed for Swales V 204 204.19 ft' 6 Length of Swale 30 ft 7 Infiltration Window?(Note:infiltration required if Longitudinal Slope<1%) Design Infiltration Rate 8.00 in/hr 8 Infiltration Window Width 4.00 ft 9 Set Swale Bottom Width b 4.00 ft 10 Set Swale Top Width 12.00 ft 11 Set Swale Depth y 1.00 ft 12 Swale Side Slopes H:1 Sxs 4.00 13 Calculate cross-sectional area Axs 8.00 8.00 ftz Axs=Y zz+by 14 Total Swale Capacity Without Driveways 240 240.00 ft' 15 Does it Have Capacity? OK 16 Time to Drain 2.6 2.55 hr 90%volume in 48-hours minimum OK Check Borrow Ditch Infiltration Windows 17 Enter Infiltration Window Length 30.00 ft 18 Enter Infiltration Window Width 4 If 19 Time to Drain 2.8 2.8 hr 90%volume in 48-hours minimum OK C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:40 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Eagle Road#lA 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 15,621 9,020 0 41,059 Acres 1.51 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.46 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) QveA 1.80 1.80 cfs Urban neighborhoods 0.50-0.70 Residential 50 10 Calculate total runoff vol V for sizing rims storage) V 2,411 2,411 ft Single Family 0.60-0.75 ( )( g primary g ) Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vr, 854 854 W Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0.20-0.25 Playgrounds 0. 0-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 241 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 2,170 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 2,411 2,411 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Bioswales & Borrow Ditches NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name ACHD Eagle Road#1A 2 Enter number of Bioswales/Borrow Ditches(25 max) 1 3 Design Storm 100 Weighted Runoff Coefficient C 0.46 Link to: LQv 4 Area A(Acres) 1.51 acres Q,V TRSS Approved discharge rate for the given storm(if applicable) 0.00 cfs 5 Design Vol With 0%Sed for Swales V 2,411 2411.00 ft' 6 Length of Swale 896 ft 7 Infiltration Window?(Note:infiltration required if Longitudinal Slope<1%) Design Infiltration Rate 8.00 in/hr 8 Infiltration Window Width 2.00 ft 9 Set Swale Bottom Width b 0.00 ft 10 Set Swale Top Width 8.00 ft 11 Set Swale Depth y 1.00 ft 12 Swale Side Slopes H:1 Sxs 4.00 13 Calculate cross-sectional area Axs 4.00 4.00 ft' Axs=Y zz+by 14 Total Swale Capacity Without Driveways 3,584 3584.00 ft' 15 Does it Have Capacity? OK 16 Time to Drain 2.0 2.02 hr 90%volume in 48-hours minimum OK Check Borrow Ditch Infiltration Windows 17 Enter Infiltration Window Length 48.00 ft 18 Enter Infiltration Window Width 2 If 19 Time to Drain 41.9 41.9 hr 90%volume in 48-hours minimum OK C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:40 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name ACHD Eagle Road#113 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 11,082 9,473 0 26,569 Acres 1.08 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.20 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.51 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc 2.58 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) peak 1.41 1.41 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(for sizing primary storage) V 1,889 1,889 ft Multi-family 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 80th 0.34 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 669 669 fY Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 0.00 cfs Parks,cemeteries 0. Playgrounds 0.20-0.0-0.35 5 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 095 Basin Foreba V 189 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 1,700 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 1,889 1,889 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:34 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Bioswales & Borrow Ditches NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name ACHD Eagle Road#16 2 Enter number of Bioswales/Borrow Ditches(25 max) 1 3 Design Storm 100 Weighted Runoff Coefficient C 0.51 Link to: LQv 4 Area A(Acres) 1.08 acres Q,V TRSS Approved discharge rate for the given storm(if applicable) 0.00 cfs 5 Design Vol With 0%Sed for Swales V 1,889 1889.32 ft' 6 Length of Swale 646 ft 7 Infiltration Window?(Note:infiltration required if Longitudinal Slope<1%) Design Infiltration Rate 8.00 in/hr 8 Infiltration Window Width 2.00 ft 9 Set Swale Bottom Width b 0.00 ft 10 Set Swale Top Width 8.00 ft 11 Set Swale Depth y 1.00 ft 12 Swale Side Slopes H:1 Sxs 4.00 13 Calculate cross-sectional area Axs 4.00 4.00 ft' Axs=Y zz+by 14 Total Swale Capacity Without Driveways 2,584 2584.00 ft' 15 Does it Have Capacity? OK 16 Time to Drain 2.2 2.19 hr 90%volume in 48-hours minimum OK Check Borrow Ditch Infiltration Windows 17 Enter Infiltration Window Length 36.00 ft 18 Enter Infiltration Window Width 2 If 19 Time to Drain 43.7 43.7 hr 90%volume in 48-hours minimum OK C:\Users\cgrah\Dropbox\Projects\19022 Windrow Subdivision\Reports\Storm Drainage\ACHD_SD_CALCS_112723 12/20/2023,11:40 AM Version 10.0,May 2018