Loading...
HomeMy WebLinkAboutWPO201300022 Calculations 2013-03-27 WHITTINGTON SUBDIVISION — PHASE A HYDROLOGIC/HYDRAULIC CALCULATIONS FOR WHITTINGTON SUBDIVSION - PHASE A SWM-1 and SWM-2 March 18, 2011 Revised: October 25, 2011 LOCATION: Tax Map 90, Parcels 3, 45, 46, 47, & 48 Samuel Miller District, Albemarle County, Virginia DEVELOPER: Stonehaus tis•A,ALT •FG 2421 Ivy Road <>(J r( Charlottesville, Virginia 22903 rO i rte , PREPARED BY: • L .>r o.33028 4.Dominion Engineering & Design, LLC 0,4„. /26 a v/ 'c 172 South Pantops Drive Charlottesville, VA 22911 S'S C� P: 434.979.8121 TONAL Y F: 434.979.1681 INDEX Summary: 2-5 Unit Hydrographs 6-13 Pre-Development: Hydrographs: DA-A 14-16 Hydrographs: DA-Al 17-19 Hydrographs: DA-B1 20-22 Hydrographs: DA-B2 23-25 Post-Development - SWM-1: Detained Flood Hydrograph: (DA-M) 26-29 Post-Undetained Hydrographs: (DA-N) 30-32 Water Quality Volume Report: 33 SWM-1 & Outlet Structure: 34-39 Routed Hydrographs: 40-43 Post-Development - SWM-2: Detained Flood Hydrograph: (DA-0) 44-47 Post-Undetained Hydrographs: (DA-P) 48-50 SWM-2 & Outlet Structure: 51-56 Routed Hydrographs: 57-60 I WHITTINGTON SUBDIVISION - PHASE A *Drainage Area Maps are included on Storm Water Management Plan Run-off Summary Pre Development Drainage Area Al = 111.79 Acres Pre Development Drainage Area A2 = 10.34 Acres Pre Development Drainage Area B1 =28.78 Acres Pre Development Drainage Area B2 = 9.16 Acres Post Development Drainage Area-M = 12.20 Acs. ( Routed ) Post Development Drainage Area-N = 109.92 Acs. ( Undetained ) Post Development Drainage Area-O = 10.98 Acs. ( Routed ) Post Development Drainage Area-P = 139.28 Acs. ( Undetained ) 2 WHITTINGTON SUBDIVISION - PHASE A SWM-1 Proposed SWM - 1 Pond will provide both water quality and detention for this project. There are 2 Pre Development Drainage Areas-Al &A2. The Post Development Drainage Area is divided in 2 sub-drainage areas, Post development Drainage Area-M( 12.20 Acres) and Post development Drainage Area-N ( 109.92 Acres) Storm Water from Drainage Area-M is detained by SWM- 1 and storm water coming form Drainage Area-N is not detained by SWM - 1. We have designed SWM - 1 to provide Detention and Water Quality Wet Pond. Per Albemarle County Design Standards Manual, Section F: Q(allowable)<=Qf(Vf/VPost), where Qf is flow from the site in a well forested condition (Cn=51), Vf is volume from the site in a well forested condition, and VPost is volume from the site in post-development conditions. Pre Development Conditions: 1.5 Yr. Pre-Development Run-Off= DA-Al + DA-A2 => 90.65 cfs+ 7.80 cfs = 98.45 cfs 1.5 Yr. Pre-Development Volume =430,808 cf+ 39,640 cf=470,448 cf 2 Yr. Pre-Development Run-Off= DA-Al + DA-A2 => 96.82 cfs + 8.32 cfs = 105.14 cfs 2 Yr. Pre-Development Volume =455,202 cf+42,253 cf=497,455 cf 10 Yr. Pre-Development Run-Off= DA-Al + DA-A2 => 227.86 cfs + 19.71 cfs= 247.57 cfs 10 Yr. Pre-Development Volume= 1,004,929 cf+ 92,783 cf= 1,097,712 cf Post-Development Conditions: 1.5 Yr. Post-Development Run-Off= DA-M + DA-N => 14.57 cfs+ 95.35 cfs= 109.92 cfs 1.5 Yr. Post-Development Volume =66,211 cf+ 446,490 cf= 512,701 cf 2 Yr. Post-Development Run-Off= DA-M + DA-N => 15.34 cfs+ 101.58 cfs = 116.92 cfs 2 Yr. Post-Development Volume= 69,260 cf+472,626 cf= 541,886 cf 10 Yr. Post-Development Run-Off= DA-M + DA-N => 31.09 cfs+ 233.47 cfs= 264.56 cfs 10 Yr. Post-Development Volume= 138,085 cf+ 1,023,224 cf= 1,161,309 cfs Allowable Release Rates: Q1.5 (allowable)-Q (Undetained) = 98.45(470,448/512,701) = 90.36 cfs-95.35 cfs= -4.99 cfs* Q2 (allowable)-Q (Undetained) = 105.14(497,455/541,886) = 96.52 cfs- 101.58 cfs= -5.06 cfs* Q10 (allowable)-Q (Undetained) = 247.57(1,097,712 / 1,161,309) = 234.01 cfs-233.47 =0.54 cfs* * 3" Orifice provided to minimize release rates. ( Please Refer Calculations on following Pages ) 3 WHITTINGTON SUBDIVISION - PHASE A SWM-2 Proposed SWM -2 Pond will provide detention for this project. There are 2 Pre Development Drainage Areas- B1 & B2. The Post Development Drainage Area is divided in 2 sub-drainage areas, Post development Drainage Area-O( 10.98 Acres) and Post development Drainage Area-P ( 139.28 Acres) Storm Water from Drainage Area-O is detained by SWM-2 and storm water coming form Drainage Area-N is not detained by SWM-2. Per Albemarle County Design Standards Manual, Section F: Q(allowable)<_ (Vf I VPost), where Qf is flow from the site in a well forested condition (Cn=51), Vf is volume from the site in a well forested condition, and VPost is volume from the site in post-development conditions. Per calculations, Pre-Development Conditions: 1.5 Yr. Pre-Development Run-Off= DA-B1 + DA-B2 =>23.24 cfs+ 8.04 cfs = 31.28 cfs 1.5 Yr. Pre-Development Volume = 111,078 cf+ 35,284 cf= 146,362 cf 2 Yr. Pre-Development Run-Off= DA-B1 + DA-B2 => 24.82 cfs + 8.58 cfs = 33.40 cfs 2 Yr. Pre-Development Volume= 117,612 cf+ 37,462 cf= 155,074 cf 10 Yr. Pre-Development Run-Off= DA-B1 + DA-B2 => 58.49 cfs + 20.17 cfs = 78.66 cfs 10 Yr. Pre-Development Volume =258,746 cf+ 82,328 cf= 341,074 cf Post-Development Conditions: 1.5 Yr. Post-Development Run-Off= DA-O + DA-P => 12.33 cfs+ 23.27 cfs = 35.60 cfs 1.5 Yr. Post-Development Volume= 51,836 cf+ 109,336 cf= 161,172 cfs 2 Yr. Post-Development Run-Off= DA-O + DA-P => 13.05 cfs + 24.80 cfs = 37.85 cfs 2 Yr. Post-Development Volume = 54,450 cf+ 115,870 cf= 170,320 cf 10 Yr. Post-Development Run-Off= DA-O + DA-P => 28.02 cfs+ 58.81 cfs= 86.83 cfs 10 Yr. Post-Development Volume = 112,820 cf+ 258,746 cf= 371,566 cf Allowable Release Rates: Q1.5 (allowable)-Q (Undetained) = 31.28(146,362/ 161,172) = 29.31 cfs-23.27 cfs= 6.04 cfs Q2 (allowable)-Q (Undetained) = 33.40(155,074/ 170,320) = 30.41 cfs-24.80 cfs= 5.61 cfs Q10 (allowable)-Q (Undetained) = 78.66(341,074/371,566)= 72.20 cfs-58.81 cfs= 13.39 cfs ( Please Refer Calculations on following Pages ) 4 WHITTINGTON SUBDIVISION - PHASE A Curve Number Calculations: Typical House Roof Area: 2,500 SF (Cn=98) Typical Lead Walk: 240 SF (Cn=98) Typical Grass Yard Area: 19,500 SF (Cn=74) DA-A1, DA-A2, DA-B1, & DA-B2: For the sake of these calculations, we are assuming all of the Pre-Development drainage areas are in a well forested condition with a curve number(Cn) of 70. DA-N (109.92 Acres): Pavement Route 631 (Cn=98)-0.12 Acre 1 House (Cn=98)-0.057 Acre 1 Yard (Cn=74)-0.448 Acre 1 Lead Walk(Cn=98)-0.006 Acre Driveway (Cn=98)-0.022 Acre Offsite Single Family Lots (Cn=73)- 11.90 Acres Wooded Area (Cn=70)-97.37 Acres 0.205(98) + 0.448(74) + 11.90(73) + 97.37(70) = 71 109.267 DA-M (12.20 Acres): Existing & Proposed Pavement(Cn=98)- 1.921 Acres 7.5 Houses(Cn=98)-0.430 Acre 7 Lead Walks (Cn=098)-0.039 Acre Driveways (Cn=98)-0.226 Acre 7.5 Yards (Cn=74)-3.357 Acres Wooded Area (Cn=70)-6.227 Acres 2.616(98) + 3.357(74) + 6.227(70) =77 12.20 DA-O (10.98 Acres): Existing & Proposed Pavement(Cn=98)-0.365 Acre 6.25 Houses (Cn=98)-0.359 Acres Driveways (Cn=98)-0.240 Acre 6.25 Yards (Cn=74)-2.798 Acre 8 Lead Walks (Cn=98)-0.044 Wooded Area (Cn=70)-7.174 Acres141.07000000 1.008(98) + 2.798(74) + 7.174(70) = 74 10.98 DA-P (26.97 Acres): 0.75 Houses (Cn=98)-0.04 Pavement Route 631 (Cn=98) -0.45 Acre Wooded Area (Cn=70)-26.48 Acres 0.49(98) + 26.48(70) = 71 26.97 5 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-Al Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 238.20 (cfs) Time to Peak (Tp) = 21.29 (min) Time of Base (Tb) = 106.47 (min) Volume = 9.33 (ac-ft) Shape Factor = 484 .00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 4 .25 (min) Lag Time = 19.17 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 111.79 70 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0. 40 2-yr 24-hr Rainfall (R) = 4.00 (in) Flow Length (L) = 200.00 (ft) Land Slope (S) = 0. 13 (ft/ft) Travel Time of Sheet Flow = 16.07 (min) SHALLOW FLOW K Coefficient (K) = 0.30 Flow Length (L) = 335.00 (ft) Watercourse Slope (S) = 0.37 (ft/ft) Travel Time of Shallow Flow = 3.05 (min) Velocity (V) = 1.83 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Coef. (n) = 0.04 Flow Length (L) = 3153.00 (ft) Channel Slope (S) = 0.06 (ft/ft) Travel Time of Channel Flow = 12.83 (min) Time of Concentration (Tc) = 31.94 (min) 6 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-A2 Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 19. 97 (cfs) Time to Peak (Tp) = 23.49 (min) Time of Base (Tb) = 117.46 (min) Volume = 0.86 (ac-ft) Shape Factor = 484 .00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 4. 69 (min) Lag Time = 21. 14 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN <None> Overall Approximation 10.34 70 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0.40 2-yr 24-hr Rainfall (R) = 4 .00 (in) Flow Length (L) = 200.00 (ft) Land Slope (S) = 0.04 (ft/ft) Travel Time of Sheet Flow = 25.34 (min) SHALLOW FLOW K Coefficient (K) = 0.30 Flow Length (L) = 247.00 (ft) Watercourse Slope (S) = 0.07 (ft/ft) Travel Time of Shallow Flow = 5.22 (min) Velocity (V) = 0.79 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Ccef. (n) = 0.04 Flow Length (L) = 850.00 (ft) Channel Slope (S) = 0.03 (ft/ft) Travel Time of Channel Flow = 4 . 67 (min) Time of Concentration (Tc) = 35.24 (min) 7 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-B1 Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 61. 14 (cfs) Time to Peak (Tp) = 21. 36 (min) Time of Base (Tb) = 106.80 (min) Volume = 2.40 (ac-ft) Shape Factor = 484 .00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 4 .26 (min) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN <None> Overall Approximation 28.78 70 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0.40 2-yr 24-hr Rainfall (R) = 4 .00 (in) Flow Length (L) = 200.00 (ft) Land Slope (S) = 0.07 (ft/ft) Travel Time of Sheet Flow = 19.71 (min) SHALLOW FLOW K_Coefficient (K) = 0.30 Flow Length (L) = 368 .00 (ft) Watercourse Slope (S) = 0. 15 (ft/ft) Travel Time of Shallow Flow = 5.28 (min) Velocity (V) = 1.16 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Coef. (n) = 0.04 Flow Length (L) = 1764 .00 (ft) Channel Slope (S) = 0. 06 (ft/ft) Travel Time of Channel Flow = 7.05 (min) Time of Concentration (Tc) = 32.04 (min) 8 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-B2 Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 21.89 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94. 92 (min) Volume = 0.76 (ac-ft) Shape Factor = 484 .00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 3.79 (min) Lag Time = 17.09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN <None> Overall Approximation 9. 16 70 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0. 40 2-yr 24-hr Rainfall (R) = 4 .00 (in) Flow Length (L) = 200. 00 (ft) Land Slope (S) = 0. 06 (ft/ft) Travel Time of Sheet Flow = 21.55 (min) SHALLOW FLOW K_Coefficient (K) = 0.30 Flow Length (L) = 320.00 (ft) Watercourse Slope (S) = 0. 12 (ft/ft) Travel Time of Shallow Flow = 5.22 (min) Velocity (V) = 1. 02 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Coef. (n) = 0.04 Flow Length (L) = 411.00 (ft) Channel Slope (S) = 0.05 (ft/ft) Travel Time of Channel Flow = 1.71 (min) Time of Concentration (Tc) = 28.48 (min) 9 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-M Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 25.09 (cfs) Time to Peak (Tp) = 22.07 (min) Time of Base (Tb) = 110.33 (min) Volume = 1.02 (ac-ft) Shape Factor = 484.00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 4 . 40 (min) Lag Time = 19.86 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN <None> Overall Approximation 12.20 77 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0. 40 2-yr 24-hr Rainfall (R) = 4 .00 (in) Flow Length (L) = 200. 00 (ft) Land Slope (S) = 0.04 (ft/ft) Travel Time of Sheet Flow = 25.34 (min) SHALLOW FLOW K_Coefficient (K) = 0.30 Flow Length (L) = 247.00 (ft) Watercourse Slope (S) = 0.07 (ft/ft) Travel Time of Shallow Flow = 5.22 (min) Velocity (V) = 0.79 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Coef. (n) = 0.04 Flow Length (L) = 461.00 (ft) Channel Slope (S) = 0.03 (ft/ft) Travel Time of Channel Flow = 2.53 (min) Time of Concentration (Tc) = 33.10 (min) 10 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-N Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 235.05 (cfs) Time to Peak (Tp) = 21.22 (min) Time of Base (Tb) = 106. 10 (min) Volume = 9. 18 (ac-ft) Shape Factor = 484 .00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 4 .23 (min) Lag Time = 19. 10 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN <None> Overall Approximation 109. 92 71 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0.40 2-yr 24-hr Rainfall (R) = 4 .00 (in) Flow Length (L) = 200. 00 (ft) Land Slope (S) = 0.13 (ft/ft) Travel Time of Sheet Flow = 16.07 (min) SHALLOW FLOW K_Coefficient (K) = 0.30 Flow Length (L) = 335.00 (ft) Watercourse Slope (S) = 0.37 (ft/ft) Travel Time of Shallow Flow = 3.05 (min) Velocity (V) = 1.83 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Coef. (n) = 0.04 Flow Length (L) = 3153.00 (ft) Channel Slope (S) = 0.06 (ft/ft) Travel Time of Channel Flow = 12.71 (min) Time of Concentration (Tc) = 31.83 (min) 11 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-0 Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 26.24 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94 .92 (min) Volume = 0. 92 (ac-ft) Shape Factor = 484 .00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 3.79 (min) Lag Time = 17.09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN <None> Overall Approximation 10. 98 74 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0.40 2-yr 24-hr Rainfall (R) = 4 .00 (in) Flow Length (L) = 200. 00 (ft) Land Slope (S) = 0.06 (ft/ft) Travel Time of Sheet Flow = 21.55 (min) SHALLOW FLOW K_Coefficient (K) = 0.30 Flow Length (L) = 320.00 (ft) Watercourse Slope (S) = 0. 12 (ft/ft) Travel Time of Shallow Flow = 5.22 (min) Velocity (V) = 1.02 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Coef. (n) = 0.04 Flow Length (L) = 411.00 (ft) Channel Slope (S) = 0.05 (ft/ft) Travel Time of Channel Flow = 1.71 (min) Time of Concentration (Tc) = 28.48 (min) 12 WHITTINGTON SUBDIVISION - PHASE A Name: Unit Hydrograph DA-P Type: SCS Curvilinear [UNIT HYDROGRAPH INFORMATION] Peak Flow (Qp) = 57.29 (cfs) Time to Peak (Tp) = 21.36 (min) Time of Base (Tb) = 106.80 (min) Volume = 2.25 (ac-ft) Shape Factor = 484 .00 Time Step = 1.00 (min) Excess Rain = 1.00 (in) Storm Duration = 4 .26 (min) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN <None> Overall Approximation 26. 97 71 [TIME CONCENTRATION -- TR-55] SHEET FLOW Manning's Roughness Coef. (n) = 0.40 2-yr 24-hr Rainfall (R) = 4 . 00 (in) Flow Length (L) = 200.00 (ft) Land Slope (S) = 0.07 (ft/ft) Travel Time of Sheet Flow = 19.71 (min) SHALLOW FLOW K Coefficient (K) = 0. 30 Flow Length (L) = 368 .00 (ft) Watercourse Slope (S) = 0. 15 (ft/ft) Travel Time of Shallow Flow = 5.28 (min) Velocity (V) = 1. 16 (ft/s) CHANNEL FLOW Hydraulic Radius (R) = 0.26 (ft) Manning's Roughness Coef. (n) = 0.04 Flow Length (L) = 1764 .00 (ft) Channel Slope (S) = 0.06 (ft/ft) Travel Time of Channel Flow = 7. 05 (min) Time of Concentration (Tc) = 32.04 (min) 13 1 Y WHITTINGTON SUBDIVISION - PHASE A Name: DA-Al 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 90.65 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1542.39 (min) Volume = 9.89 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1. 00 [UNIT HYDROGRAPH INFORMATION] Number = 6 Type = SCS Curvilinear Peak Flow (Qp) = 238 .20 (cfs) Time to Peak (Tp) = 21.29 (min) Time of Base (Tb) = 106.47 (min) Volume = 9.33 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19. 17 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 111.79 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 31. 94 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 1.5 (yr) Storm Duration = 24 . 00 (hr) 14 WHITTINGTON SUBDIVISION - PHASE A Name: DA-Al 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 96.82 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1542.39 (min) Volume = 10.48 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 6 Type = SCS Curvilinear Peak Flow (Qp) = 238 .20 (cfs) Time to Peak (Tp) = 21.29 (min) Time of Base (Tb) = 106. 47 (min) Volume = 9.33 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1. 00 (in) Lag Time = 19.17 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 111.79 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 31. 94 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 15 WHITTINGTON SUBDIVISION - PHASE A Name: DA-Al 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 227.86 (cfs) Time to Peak (Tp) = 733. 00 (min) Time of Base (Tb) = 1542.39 (min) Volume = 23.07 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 6 Type = SCS Curvilinear Peak Flow (Qp) = 238.20 (cfs) Time to Peak (Tp) = 21.29 (min) Time of Base (Tb) = 106.47 (min) Volume = 9.33 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.17 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 111.79 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 31. 94 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5. 60 (in) Return Period = 10 (yr) Storm Duration = 24 .00 (hr) 16 WHITTINGTON SUBDIVISION - PHASE A Name: DA-A2 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 7.80 (cfs) Time to Peak (Tp) = 736.00 (min) Time of Base (Tb) = 1556.24 (min) Volume = 0. 91 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 7 Type = SCS Curvilinear Peak Flow (Qp) = 19. 97 (cfs) Time to Peak (Tp) = 23.49 (min) Time of Base (Tb) = 117.46 (min) Volume = 0.86 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 21. 14 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 10.34 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 35.24 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 17 WHITTINGTON SUBDIVISION - PHASE A Name: DA-A2 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 8.32 (cfs) Time to Peak (Tp) = 736.00 (min) Time of Base (Tb) = 1556.24 (min) Volume = 0. 97 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 7 Type = SCS Curvilinear Peak Flow (Qp) = 19. 97 (cfs) Time to Peak (Tp) = 23.49 (min) Time of Base (Tb) = 117. 46 (min) Volume = 0.86 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 21.14 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 10.34 70 [TIME CONCENTRATION -- User Defined] Time of Concentration (Tc) = 35.24 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 18 WHITTINGTON SUBDIVISION - PHASE A Name: DA-A2 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 19.71 (cfs) Time to Peak (Tp) = 734 .00 (min) Time of Base (Tb) = 1556.24 (min) Volume = 2.13 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 7 Type = SCS Curvilinear Peak Flow (Qp) = 19. 97 (cfs) Time to Peak (Tp) = 23.49 (min) Time of Base (Tb) = 117. 46 (min) Volume = 0.86 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 21. 14 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 10.34 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 35.24 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5. 60 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 19 WHITTINGTON SUBDIVISION - PHASE A Name: DA-Bl 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 23.24 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1542.83 (min) Volume = 2.55 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 8 Type = SCS Curvilinear Peak Flow (Qp) = 61. 14 (cfs) Time to Peak (Tp) = 21.36 (min) Time of Base (Tb) = 106.80 (min) Volume = 2.40 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 28 .78 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 32.04 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 1.5 (yr) Storm Duration = 24 .00 (hr) 20 l I WHITTINGTON SUBDIVISION - PHASE A Name: DA-B1 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 24.82 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1542.83 (min) Volume = 2.70 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 8 Type = SCS Curvilinear Peak Flow (Qp) = 61.14 (cfs) Time to Peak (Tp) = 21.36 (min) Time of Base (Tb) = 106.80 (min) Volume = 2.40 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 28.78 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 32.04 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 21 WHITTINGTON SUBDIVISION - PHASE A Name: DA-Bl 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 58.49 (cfs) Time to Peak (Tp) = 732.00 (min) Time of Base (Tb) = 1542.83 (min) Volume = 5. 94 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 8 Type = SCS Curvilinear Peak Flow (Qp) = 61. 14 (cfs) Time to Peak (Tp) = 21.36 (min) Time of Base (Tb) = 106.80 (min) Volume = 2.40 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 28.78 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 32.04 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5. 60 (in) Return Period = 10 (yr) Storm Duration = 24.00 (hr) 22 WHITTINGTON SUBDIVISION - PHASE A Name: DA-B2 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 8.04 (cfs) Time to Peak (Tp) = 731.00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 0.81 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 9 Type = SCS Curvilinear Peak Flow (Qp) = 21.89 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94 . 92 (min) Volume = 0.76 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 17 .09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 9. 16 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 28.48 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 1.5 (yr) Storm Duration = 24.00 (hr) 23 t 1 WHITTINGTON SUBDIVISION - PHASE A Name: DA-B2 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 8.58 (cfs) Time to Peak (Tp) = 731.00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 0.86 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 9 Type = SCS Curvilinear Peak Flow (Qp) = 21.89 (cfs) Time to Peak (Tp) = 18 . 98 (min) Time of Base (Tb) = 94 . 92 (min) Volume = 0.76 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 17.09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 9.16 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 28.48 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 24 WHITTINGTON SUBDIVISION - PHASE A Name: DA-B2 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 20.17 (cfs) Time to Peak (Tp) = 730. 00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 1.89 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 9 Type = SCS Curvilinear Peak Flow (Qp) = 21.89 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94. 92 (min) Volume = 0.76 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 17.09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 9.16 70 [TIME CONCENTRATION] Time of Concentration (Tc) = 28.48 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5. 60 (in) Return Period = 10 (yr) Storm Duration = 24 .00 (hr) 25 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 14.57 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 1.52 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 10 Type = SCS Curvilinear Peak Flow (Qp) = 25.09 (cfs) Time to Peak (Tp) = 22.07 (min) Time of Base (Tb) = 110.33 (min) Volume = 1.02 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.86 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 12.20 77 [TIME CONCENTRATION] Time of Concentration (Tc) = 33. 10 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 1. 5 (yr) Storm Duration = 24 .00 (hr) 26 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 15.34 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 1.59 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 10 Type = SCS Curvilinear Peak Flow (Qp) = 25.09 (cfs) Time to Peak (Tp) = 22.07 (min) Time of Base (Tb) = 110.33 (min) Volume = 1.02 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.86 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 12.20 77 [TIME CONCENTRATION] Time of Concentration (Tc) = 33. 10 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 27 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 31.09 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 3. 17 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 10 Type = SCS Curvilinear Peak Flow (Qp) = 25.09 (cfs) Time to Peak (Tp) = 22.07 (min) Time of Base (Tb) = 110.33 (min) Volume = 1.02 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19. 86 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 12.20 77 [TIME CONCENTRATION] Time of Concentration (Tc) = 33. 10 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5. 60 (in) Return Period = 10 (yr) Storm Duration = 24 .00 (hr) 28 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M 100-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 62.10 (cfs) Time to Peak (Tp) = 732.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 6.37 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 10 Type = SCS Curvilinear Peak Flow (Qp) = 25.09 (cfs) Time to Peak (Tp) = 22.07 (min) Time of Base (Tb) = 110.33 (min) Volume = 1.02 (ac-ft) Shape Factor = 484 . 00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.86 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 12.20 77 [TIME CONCENTRATION] Time of Concentration (Tc) = 33.10 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 9. 10 (in) Return Period = 100 (yr) Storm Duration = 24 .00 (hr) 29 { WHITTINGTON SUBDIVISION - PHASE A Name: DA-N 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 95.35 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1541. 15 (min) Volume = 10.25 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 11 Type = SCS Curvilinear Peak Flow (Qp) = 235.05 (cfs) Time to Peak (Tp) = 21.22 (min) Time of Base (Tb) = 106. 10 (min) Volume = 9. 18 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19. 10 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 109. 92 71 [TIME CONCENTRATION] Time of Concentration (Tc) = 31.83 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 1.5 (yr) Storm Duration = 24 .00 (hr) 30 WHITTINGTON SUBDIVISION - PHASE A Name: DA-N 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 101.58 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1541. 15 (min) Volume = 10.85 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1. 00 [UNIT HYDROGRAPH INFORMATION] Number = 11 Type = SCS Curvilinear Peak Flow (Qp) = 235. 05 (cfs) Time to Peak (Tp) = 21.22 (min) Time of Base (Tb) = 106.10 (min) Volume = 9.18 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.10 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 109. 92 71 [TIME CONCENTRATION] Time of Concentration (Tc) = 31.83 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 31 • WHITTINGTON SUBDIVISION - PHASE A Name: DA-N 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 233.47 (cfs) Time to Peak (Tp) = 732.00 (min) Time of Base (Tb) = 1541. 15 (min) Volume = 23.49 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 11 Type = SCS Curvilinear Peak Flow (Qp) = 235. 05 (cfs) Time to Peak (Tp) = 21.22 (min) Time of Base (Tb) = 106.10 (min) Volume = 9. 18 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19. 10 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 109. 92 71 [TIME CONCENTRATION -- User Defined] Time of Concentration (Tc) = 31.83 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5. 60 (in) Return Period = 10 (yr) Storm Duration = 24.00 (hr) 32 1 . WHITTINGTON SUBDIVISION - PHASE A RESERVOIR REPORT Name: SWM-1 WETPOND STORAGE ( WATER QUALITY VOLUME REPORT ) [RATING CURVE LIMIT] Minimum Elevation = 484.75 (ft) Maximum Elevation = 493.30 (ft) Elevation Increment = 0. 10 (ft) Number Elevation Area Ave Area Volume Cumulative Volume (ft) (sq ft) (sq ft) (cu ft) (cu ft) 1 483.49 0.00 0.00 0.00 0.00 2 483.50 12292.00 6146.00 61.46 61.46 3 484 .00 12985.00 12638.50 6319.25 6380.71 4 486.00 16722.00 14853.50 29707 .00 36087.71 5 487.50 22550.00 19636.00 29454.00 65541.71 6 490.00 29627.00 26088.50 65221.25 130762. 96 7 492.00 33350.00 31488.50 62977.00 193739. 96 8 493.30 36500.00 34925.00 45402.50 239142.46 Quality Volume Required = 4 X (WQ Volume) WQ Volume = (1/2in) /12 X impervious area (Sq. Ft. ) (1/2in) /12 X 43, 931 Sq. Ft. = 4755.30 Cu. Ft. 4 X WQ Volume = 19021.20 Cu. Ft. (Please Refer attached Water Quality Calc. ) Provided Water Quality Volume = 65,541.71 cu. Ft. 33 WHITTINGTON SUBDIVISION - PHASE A RESERVOIR REPORT Name: STORM WATER MANAGEMENT - 1 [RATING CURVE LIMIT] Minimum Elevation = 484 .75 (ft) Maximum Elevation = 493.30 (ft) Elevation Increment = 0. 10 (ft) [STAGE STORAGE INFORMATION] Storage Method: User-Defined Storage [DISCHARGE INFORMATION] Structure Number: 1 Type: Name: SWM-1 STAND PIPE Structure Number: 2 Type: Trapezoidal Weir Suppressed Name: SWM-1 WEIR [RESERVOIR STAGE STORAGE/DISCHARGE] Elevation Stage Area Storage Discharge (ft) (ft) (sq ft) (cu ft) (cfs) 487 .45 2.70 0.00 0.00 0.00 487.55 2.80 22691.54 1134 .58 0.01 487. 65 2. 90 22974 . 62 3417.88 0.04 487.75 3. 00 23257.70 5729.50 0.08 487.85 3.10 23540.78 8069.42 0. 11 487. 95 3.20 23823.86 10437 . 66 0.13 488 .05 3.30 24106. 94 12834 .20 0.15 488. 15 3.40 24390.02 15259.04 0.17 488.25 3.50 24673.10 17712.20 0. 19 488.35 3. 60 24956. 18 20193. 66 0.20 488.45 3.70 25239.26 22703. 44 0.21 488.55 3.80 25522.34 25241.52 0.23 488. 65 3. 90 25805.42 27807. 90 0.24 488.75 4 .00 26088.50 30402. 60 0.25 488.85 4 . 10 26371.58 33025. 60 0.26 488. 95 4 .20 26654 . 66 35676. 92 0.27 489.05 4 .30 26937.74 38356.54 0.28 489.15 4.40 27220.82 41064 .46 0.29 489.25 4 .50 27503. 90 43800.70 0.30 489.35 4 . 60 27786. 98 46565.24 0.31 489. 45 4 .70 28070.06 49358.10 0.32 489.55 4.80 28353. 14 52179.26 0.33 489. 65 4 . 90 28636.22 55028.72 0.34 489.75 5.00 28919.30 57906.50 0.34 489.85 5.10 29202.38 60812.58 0.35 489. 95 5.20 29485.46 63746. 98 0.36 490.05 5.30 29720.08 66707 .25 0.37 490. 15 5.40 29906.22 69688.57 0.38 490.25 5.50 30092.38 72688.50 0. 38 490.35 5. 60 30278.53 75707.04 0.39 490.45 5.70 30464 . 67 78744 .20 0.40 34 i • WHITTINGTON SUBDIVISION - PHASE A 490.55 5.80 30650.83 81799. 98 0.40 490. 65 5. 90 30836. 97 84874 .37 0.41 490.75 6.00 31023.13 87967.37 0.42 490.85 6. 10 31209.28 91078. 99 0.42 490. 95 6.20 31395.42 94209.23 0.43 491.05 6.30 31581.58 97358. 08 0.44 491. 15 6.40 31767.72 100525.54 0.44 491.25 6.50 31953.88 103711. 62 0. 45 491.35 6. 60 32140.03 106916.32 0.46 491.45 6.70 32326. 17 110139. 63 0.46 491.55 6.80 32512.33 113381. 55 0.47 491. 65 6. 90 32698.47 116642.09 0. 47 491.75 7.00 32884 . 63 119921.25 0. 48 491.85 7. 10 33070.78 123219.02 0. 95 491. 95 7.20 33256. 92 126535. 40 3.38 492.05 7.30 33471. 15 129871.81 8 . 15 492.15 7 .40 33713.46 133231.04 14 .52 492.25 7.50 33955.77 136614 .50 22.25 492.35 7. 60 34198.08 140022. 19 31.21 492.45 7.70 34440.38 143454 . 12 41.34 492.55 7 .80 34682. 69 146910.27 52.58 492. 65 7. 90 34925.00 150390. 65 64 . 90 492.75 8.00 35167.31 153895.27 78.28 492.85 8. 10 35409. 62 157424 . 12 88.13 492. 95 8.20 35651. 92 160977 . 19 97 .31 493.05 8 .30 35894 .23 164554 .50 107 .23 493. 15 8.40 36136.54 168156.04 117. 88 493.25 8.50 36378. 85 171781.81 129.29 Maximum Storage = 173603.78 (cu ft) Maximum Discharge = 135.27 (cfs) 35 • WHITTINGTON SUBDIVISION - PHASE A OUTLET STRUCTURE REPORT Type : Stand Pipe Name : SWM-1 STAND PIPE [RATING CURVE LIMIT] Minimum Elevation = 484 .75 (ft) Maximum Elevation = 493.30 (ft) Elevation Increment = 0.10 (ft) [STAND PIPE INFORMATION] [ORIFICE INFORMATION] Diameter = 4 .00 (ft) Crest Length = 12.57 (ft) Effective Crest Length = 12.57 (ft) Orifice Coefficient = 0. 60 Fractional Open Area = 1.00 [ORIFICE EQUATION] Q = Co*A( (2gh) /k) ^0.5 [DEFINITIONS] Co = Orifice Coefficient A = Wetted Area, (sq ft) [WEIR INFORMATION] Crest Elevation = 491.80 (ft) Weir Coefficient = 3.33 Exponential = 1.50 [WEIR EQUATION] Q = Cw * L * H^exp [DEFINITIONS] Cw = Weir Coefficient H = Headwater depth above inlet control section invert ft L = Crest lenght ft [OPTIONAL ORIFICE INFORMATION] Type : Circular Orifice [OPTIONAL ORIFICE INFORMATION] Diameter = 0.25 (ft) ) Invert Elevation = 487.50 (ft) Orifice Coefficient = 0. 60 Number of Openings = 1 36 WHITTINGTON SUBDIVISION - PHASE A [CULVERT INFORMATION] Type: Circular Concrete - Square Edge with Headwall [OUTLET STRUCTURE INFORMATION] Diameter = 24 .00 (in) Invert Elevation = 484 .75 (ft) Pipe Length = 75.00 (ft) Slope = 0.01 Manning's n Value = 0.01 Orifice Coefficient = 0. 60 Tailwater Elevation = 484 .00 (ft) Number of Barrels = 1 [UNSUBMERGED EQUATION] H/Diam = Hc/Diam+K* (Q/ (A*Diam^0.5) ) ^M-0.5*S Coefficient K = 0.01 Coefficient M = 2.00 Q Maximum = 15.55 [SUBMERGED EQUATION] H/Diam = c* (Q/ (A*Diam^0.5) ) ^2+Y-0.5*S Coefficient c = 0.04 Coefficient Y = 0. 67 Q Minimum = 17 .77 STAND PIPE OUTLET STRUCTURE REPORT Elevation Stage Weirs Orifices Stand Pipe Culvert Total (ft) (ft) (cfs) (cfs) (cfs) (cfs) (cfs) 484 .75 0.00 0.00 0.00 0.00 0.00 0.00 484 .85 0. 10 0. 00 0.00 0. 00 0.06 0.00 484 . 95 0.20 0.00 0.00 0.00 0.21 0.00 485.05 0.30 0.00 0. 00 0.00 0.46 0.00 485.15 0.40 0.00 0.00 0.00 0.79 0.00 485.25 0.50 0.00 0.00 0.00 1.20 0.00 485.35 0. 60 0.00 0.00 0.00 1.70 0.00 485. 45 0.70 0.00 0.00 0.00 2.25 0. 00 485.55 0.80 0.00 0.00 0.00 2.89 0.00 485. 65 0. 90 0.00 0.00 0.00 3.55 0.00 485.75 1.00 0.00 0. 00 0.00 4 .28 0.00 485.85 1. 10 0.00 0.00 0.00 5.04 0.00 485. 95 1.20 0.00 0.00 0.00 5.86 0.00 486.05 1.30 0.00 0.00 0.00 6. 68 0.00 486. 15 1.40 0.00 0.00 0.00 7.53 0.00 486.25 1.50 0.00 0.00 0.00 8.41 0.00 486.35 1. 60 0.00 0.00 0.00 9.29 0.00 486.45 1.70 0.00 0.00 0.00 10. 17 0.00 486.55 1.80 0.00 0.00 0.00 11.06 0.00 486. 65 1. 90 0.00 0.00 0.00 11. 97 0. 00 486.75 2.00 0.00 0.00 0.00 12.85 0.00 486.85 2.10 0.00 0.00 0.00 13.73 0.00 486. 95 2.20 0.00 0.00 0.00 14 . 61 0.00 487 .05 2.30 0.00 0.00 0.00 15.46 0.00 487 . 15 2.40 0.00 0.00 0.00 15.55 0.00 37 WHITTINGTON SUBDIVISION - PHASE A 487.25 2.50 0.00 0.00 0.00 16. 66 0.00 487.35 2. 60 0.00 0.00 0.00 17 .77 0.00 487.45 2.70 0.00 0.00 0.00 18.45 0.00 487.55 2.80 0.00 0.01 0.00 19. 11 0.01 487. 65 2. 90 0.00 0.04 0.00 19.75 0.04 487.75 3.00 0.00 0.08 0.00 20.37 0.08 487.85 3. 10 0.00 0. 11 0.00 20. 97 0.11 487. 95 3.20 0.00 0. 13 0.00 21.55 0. 13 488.05 3.30 0.00 0.15 0.00 22. 12 0. 15 488. 15 3.40 0.00 0. 17 0.00 22. 67 0. 17 488.25 3.50 0.00 0.19 0.00 23.21 0. 19 488. 35 3. 60 0.00 0.20 0.00 23.74 0.20 488 .45 3.70 0.00 0.21 0.00 24 .26 0.21 488.55 3.80 0.00 0.23 0.00 24 .76 0.23 488. 65 3. 90 0.00 0.24 0. 00 25.26 0.24 488.75 4 .00 0.00 0.25 0.00 25.74 0.25 488.85 4 . 10 0.00 0.26 0.00 26.22 0.26 488. 95 4.20 0.00 0.27 0.00 26. 69 0.27 489.05 4 .30 0.00 0.28 0.00 27. 15 0.28 489. 15 4 .40 0.00 0.29 0.00 27. 60 0.29 489.25 4 .50 0.00 0.30 0.00 28 .05 0.30 489.35 4 . 60 0.00 0. 31 0.00 28 .49 0.31 489.45 4 .70 0.00 0.32 0.00 28 . 92 0.32 489.55 4.80 0.00 0.33 0.00 29.34 0.33 489. 65 4 . 90 0.00 0.34 0.00 29.76 0.34 489.75 5.00 0.00 0.34 0.00 30. 18 0.34 489.85 5. 10 0.00 0.35 0.00 30.59 0.35 489. 95 5.20 0. 00 0.36 0.00 30. 99 0. 36 490.05 5.30 0.00 0.37 0.00 31.39 0.37 490.15 5.40 0.00 0.38 0.00 31.78 0.38 490.25 5.50 0.00 0.38 0.00 32. 17 0.38 490.35 5. 60 0.00 0.39 0.00 32.55 0.39 490.45 5.70 0.00 0.40 0.00 32. 93 0. 40 490.55 5.80 0.00 0.40 0.00 33.30 0. 40 490. 65 5. 90 0.00 0. 41 0.00 33. 67 0.41 490.75 6.00 0.00 0. 42 0. 00 34 .04 0.42 490.85 6.10 0.00 0.42 0.00 34 .40 0.42 490. 95 6.20 0.00 0.43 0.00 34 .76 0.43 491.05 6.30 0.00 0.44 0.00 35. 12 0.44 491. 15 6.40 0.00 0.44 0.00 35.47 0.44 491.25 6.50 0. 00 0.45 0.00 35.81 0.45 491.35 6.60 0.00 0. 46 0.00 36. 16 0.46 491.45 6.70 0.00 0. 46 0.00 36.50 0.46 491.55 6.80 0.00 0.47 0.00 36.84 0.47 491. 65 6. 90 0.00 0.47 0. 00 37.17 0.47 491.75 7.00 0.00 0.48 0.00 37.51 0. 48 491.85 7. 10 0.00 0.49 0.47 37 .83 0. 95 491. 95 7.20 0.00 0.49 2.43 38 . 16 2. 92 492.05 7.30 0.00 0.50 5.23 38.48 5.73 492. 15 7.40 0.00 0.50 8. 67 38.81 9.17 492.25 7 .50 0.00 0.51 12. 63 39. 12 13. 14 492.35 7 . 60 0.00 0.51 17.07 39. 44 17 .58 492.45 7.70 0.00 0.52 21. 93 39.75 22. 45 492.55 7.80 0.00 0.52 27.18 40. 06 27.71 492. 65 7. 90 0.00 0.53 32.79 40.37 33.32 492.75 8.00 0.00 0.53 38.75 40. 68 39.28 38 WHITTINGTON SUBDIVISION - PHASE A 492.85 8.10 0.00 0.54 45.03 40. 98 40.98 492. 95 8.20 0.00 0.55 51. 61 41.28 41.28 493.05 8.30 0.00 0.55 56.51 41.58 41.58 493. 15 8.40 0.00 0.56 61.29 41.88 41.88 493.25 8.50 0.00 0.56 66.07 42. 17 42. 17 493.30 8.55 0.00 0. 56 68 .46 42.32 42.32 OUTLET STRUCTURE REPORT Type : Trapezoidal Weir Name : SWM-1 WEIR [RATING CURVE LIMIT] Minimum Elevation = 491. 90 (ft) Maximum Elevation = 493.30 (ft) Elevation Increment = 0. 10 (ft) [OUTLET STRUCTURE INFORMATION] Crest Length = 12.00 (ft) Angle of Walls = 154 .0000 Crest Elevation = 491. 90 (ft) Weir Coefficient = 3.33 Exponential = 1.50 [TRAPEZOIDAL [TRAPEZOIDAL EQUATION] Q = Cw * ( L + 0.8H * tan ( ang/2.0 ) ) * H^exp [DEFINITIONS] Cw = Weir Coefficient H = Headwater depth above inlet control section invert L = Crest lenght ang = Angle of the walls [MAXIMUM DISCHARGE] Q = 92. 95 (cfs) [WEIR STAGE VS. DISCHARGE] Elevation (ft) Stage (ft) Discharge (cfs) 491. 90 0.00 0. 00 492.00 0. 10 1. 30 492.10 0.20 3.78 492.20 0.30 7 .13 492.30 0.40 11.28 492. 40 0.50 16. 17 492.50 0. 60 21.79 492. 60 0.70 28.13 492.70 0. 80 35.20 492.80 0. 90 42. 99 492. 90 1.00 51.50 493.00 1.10 60.75 493.10 1.20 70.73 493.20 1.30 81.46 493.30 1.40 92. 95 39 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M - 1.5-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 0.22 (cfs) Time to Peak (Tp) = 1440.00 (min) Time of Base (Tb) = 1440.00 (min) Volume = 0. 18 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 489.77 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 6 Name = SWM-1 24-Hour Storage Type = User-Defined Area Maximum Storage = 173603.78 (cu ft) Maximum Discharge = 135.27 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 51 Name = DA-M 1.5 Year Peak Flow (Qp) = 14 .57 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 1.52 (ac-ft) Flow Multiplier = 1.00 40 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M - 2-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 0.34 (cfs) Time to Peak (Tp) = 1440.00 (min) Time of Base (Tb) = 1440.00 (min) Volume = 0.32 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 489.67 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 6 Name = SWM-1 24-Hour Storage Type = User-Defined Area Maximum Storage = 173603.78 (cu ft) Maximum Discharge = 135.27 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 52 Name = DA-M 2 Year Peak Flow (Qp) = 15.34 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 1.59 (ac-ft) Flow Multiplier = 1.00 41 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M - 10-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 0.48 (cfs) Time to Peak (Tp) = 1440.00 (min) Time of Base (Tb) = 1440.00 (min) Volume = 0. 46 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 491.69 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 6 Name = SWM-1 24-Hour Storage Type = User-Defined Area Maximum Storage = 173603.78 (cu ft) Maximum Discharge = 135.27 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 53 Name = DA-M 10 Year Peak Flow (Qp) = 31.09 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 3. 17 (ac-ft) Flow Multiplier = 1.00 42 WHITTINGTON SUBDIVISION - PHASE A Name: DA-M - 100-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 26.79 (cfs) Time to Peak (Tp) = 756.00 (min) Time of Base (Tb) = 1440.00 (min) Volume = 3.53 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 492.30 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 6 Name = SWM-1 24-Hour Storage Type = User-Defined Area Maximum Storage = 173603.78 (cu ft) Maximum Discharge = 135.27 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 66 Name = DA-M 100-Year Peak Flow (Qp) = 62. 10 (cfs) Time to Peak (Tp) = 732.00 (min) Time of Base (Tb) = 1545.49 (min) Volume = 6.37 (ac-ft) Flow Multiplier = 1.00 43 ! r WHITTINGTON SUBDIVISION - PHASE A Name: DA-O - 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 12.33 (cfs) Time to Peak (Tp) = 731.00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 1. 19 (ac-ft) Time Step = 1. 00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 12 Type = SCS Curvilinear Peak Flow (Qp) = 26.24 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94 . 92 (min) Volume = 0. 92 (ac-ft) Shape Factor = 484 . 00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 17.09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 10. 98 74 [TIME CONCENTRATION] Time of Concentration (Tc) = 28 .48 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 1.5 (yr) Storm Duration = 24.00 (hr) 44 WHITTINGTON SUBDIVISION - PHASE A Name: DA-O - 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 13.05 (cfs) Time to Peak (Tp) = 731.00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 1.25 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 12 Type = SCS Curvilinear Peak Flow (Qp) = 26.24 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94 . 92 (min) Volume = 0. 92 (ac-ft) Shape Factor = 484 . 00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 17.09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 10. 98 74 [TIME CONCENTRATION] Time of Concentration (Tc) = 28.48 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 45 WHITTINGTON SUBDIVISION - PHASE A Name: DA-O - 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 28.02 (cfs) Time to Peak (Tp) = 729. 00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 2.59 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 12 Type = SCS Curvilinear Peak Flow (Qp) = 26.24 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94 . 92 (min) Volume = 0. 92 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 17 .09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 10. 98 74 [TIME CONCENTRATION] Time of Concentration (Tc) = 28.48 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5. 60 (in) Return Period = 10 (yr) Storm Duration = 24 .00 (hr) 46 • WHITTINGTON SUBDIVISION - PHASE A Name: DA-0 - 100-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 58.44 (cfs) Time to Peak (Tp) = 729.00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 5.39 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 12 Type = SCS Curvilinear Peak Flow (Qp) = 26.24 (cfs) Time to Peak (Tp) = 18. 98 (min) Time of Base (Tb) = 94 . 92 (min) Volume = 0. 92 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 17.09 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 10. 98 74 [TIME CONCENTRATION] Time of Concentration (Tc) = 28.48 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 9. 10 (in) Return Period = 100 (yr) Storm Duration = 24 .00 (hr) 47 o WHITTINGTON SUBDIVISION — PHASE A Name: DA-P 1.5-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 23.27 (cfs) Time to Peak (Tp) = 733. 00 (min) Time of Base (Tb) = 1542.83 (min) Volume = 2.51 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 13 Type = SCS Curvilinear Peak Flow (Qp) = 57.29 (cfs) Time to Peak (Tp) = 21.36 (min) Time of Base (Tb) = 106.80 (min) Volume = 2.25 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 26. 97 71 [TIME CONCENTRATION] Time of Concentration (Tc) = 32.04 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3. 60 (in) Return Period = 1.5 (yr) Storm Duration = 24 . 00 (hr) 48 WHITTINGTON SUBDIVISION - PHASE A Name: DA-P 2-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 24.80 (cfs) Time to Peak (Tp) = 733.00 (min) Time of Base (Tb) = 1542.83 (min) Volume = 2. 66 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1. 00 [UNIT HYDROGRAPH INFORMATION] Number = 13 Type = SCS Curvilinear Peak Flow (Qp) = 57 .29 (cfs) Time to Peak (Tp) = 21.36 (min) Time of Base (Tb) = 106. 80 (min) Volume = 2.25 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 26. 97 71 [TIME CONCENTRATION] Time of Concentration (Tc) = 32. 04 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 3.70 (in) Return Period = 2 (yr) Storm Duration = 24 .00 (hr) 49 WHITTINGTON SUBDIVISION - PHASE A Name: DA-P - 10-Year Type: Computed Flood [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 58.81 (cfs) Time to Peak (Tp) = 732.00 (min) Time of Base (Tb) = 1542.83 (min) Volume = 5. 94 (ac-ft) Time Step = 1.00 (min) Flow Multiplier = 1.00 [UNIT HYDROGRAPH INFORMATION] Number = 13 Type = SCS Curvilinear Peak Flow (Qp) = 57.29 (cfs) Time to Peak (Tp) = 21.36 (min) Time of Base (Tb) = 106.80 (min) Volume = 2.25 (ac-ft) Shape Factor = 484 .00 Time Step: = 1.00 (min) Excess Rain = 1.00 (in) Lag Time = 19.22 (min) [BASIN INFORMATION] [WEIGHTED WATERSHED AREA] Description Area CN Overall Approximation 26. 97 71 [TIME CONCENTRATION] Time of Concentration (Tc) = 32.04 (min) [RAINFALL DESCRIPTION] Distribution Type = SCS II Total Precipitation = 5.70 (in) Return Period = 10 (yr) Storm Duration = 24 . 00 (hr) 50 WHITTINGTON SUBDIVISION - PHASE A RESERVOIR REPORT Reservoir Number: 1 Name: SWM-2 [RATING CURVE LIMIT] Minimum Elevation = 486.00 (ft) Maximum Elevation = 495.00 (ft) Elevation Increment = 0. 10 (ft) [STAGE STORAGE INFORMATION] Storage Method: User-Defined Storage Input Method: Area Number Elevation Area Ave Area Volume Cumulative Volume (ft) (sq ft) (sq ft) (cu ft) (cu ft) 1 485. 99 0.00 0.00 0.00 0.00 2 486.00 4000.00 2000.00 20.00 20.00 3 488.00 5850.00 4925.00 9850.00 9870.00 4 490.00 7900.00 6875.00 13750.00 23620. 00 5 492.00 10500.00 9200.00 18400.00 42020.00 6 494 .00 13000.00 11750.00 23500.00 65520. 00 7 495.00 14500.00 13750.00 13750.00 79270.00 [DISCHARGE INFORMATION] Structure Number: 1 Type: Name: SWM-2 STAND PIPE Structure Number: 2 Type: Trapezoidal Weir Name: SWM-2 WEIR 51 I 4 . WHITTINGTON SUBDIVISION - PHASE A [RESERVOIR STAGE STORAGE/DISCHARGE] Elevation Stage Area Storage Discharge (ft) (ft) (sq ft) (cu ft) (cfs) 486.00 0.00 0. 00 0.00 0.00 486.20 0.20 4185.00 618.50 0.06 486. 40 0.40 4370.00 1474 .00 0.12 486. 60 0. 60 4555.00 2366.50 0.16 486.80 0.80 4740.00 3296.00 0. 19 487.00 1. 00 4925.00 4262.50 0.22 487.20 1.20 5110.00 5266.00 0.24 487 .40 1.40 5295.00 6306.50 0.27 487. 60 1. 60 5480.00 7384 .00 0.29 487.80 1.80 5665.00 8498.50 0.31 488.00 2.00 5850.00 9650.00 0.32 488.20 2.20 6055.00 10840.50 0. 34 488.40 2.40 6260.00 12072.00 0.36 488. 60 2. 60 6465. 00 13344 .50 0.37 488.80 2.80 6670.00 14658.00 0.39 489.00 3.00 6875.00 16012.50 0.40 489.20 3.20 7080.00 17408.00 0.41 489.40 3.40 7285.00 18844 .50 0.43 489. 60 3. 60 7490.00 20322.00 0.44 489.80 3.80 7695.00 21840.50 0.45 490.00 4 .00 7900.00 23400. 00 0.47 490.20 4 .20 8160.00 25006. 00 0.48 490.40 4 . 40 8420.00 26664 . 00 0.49 490. 60 4 . 60 8680.00 28374 . 00 0.50 490.80 4 . 80 8940. 00 30136. 00 0. 51 491.00 5.00 9200.00 31950. 00 0.52 491.20 5.20 9460.00 33816.00 0.53 491.40 5.40 9720.00 35734 .00 0.54 491. 60 5. 60 9980.00 37704 .00 0.55 491.80 5.80 10240.00 39726.00 0.56 492. 00 6.00 10500.00 41800.00 0.57 492.20 6.20 10750.00 43925.00 0.58 492.40 6. 40 11000.00 46100.00 0.59 492. 60 6. 60 11250.00 48325.00 1. 92 492.80 6. 80 11500.00 50600.00 7.49 493.00 7.00 11750.00 52925.00 15.41 493.20 7.20 12000.00 55300.00 25.14 493.40 7.40 12250.00 57725. 00 36.37 493. 60 7. 60 12500.00 60200. 00 40. 94 493.80 7.80 12750.00 62725. 00 48.28 494 .00 8.00 13000.00 65300. 00 59. 17 494.20 8.20 13300.00 67930.00 73.25 494 .40 8.40 13600.00 70620.00 90.43 494 . 60 8. 60 13900.00 73370.00 110.70 494 .80 8.80 14200.00 76180. 00 134.09 495.00 9.00 14500.00 79050. 00 160. 64 Maximum Storage = 79050.00 (cu ft) Maximum Discharge = 160.64 (cfs) 52 WHITTINGTON SUBDIVISION - PHASE A OUTLET STRUCTURE REPORT Structure Number : 3 Type : Stand Pipe Name : SWM-2 STAND PIPE [RATING CURVE LIMIT] Minimum Elevation = 486.00 (ft) Maximum Elevation = 495. 00 (ft) Elevation Increment = 0.10 (ft) [STAND PIPE INFORMATION] [ORIFICE INFORMATION] Diameter = 4 .00 (ft) Crest Length = 12. 57 (ft) Effective Crest Length = 12.57 (ft) Orifice Coefficient = 0. 60 Fractional Open Area = 1.00 [ORIFICE EQUATION] Q = Co*A( (2gh) /k) ^0.5 [DEFINITIONS] Co = Orifice Coefficient A = Wetted Area, (sq ft) [WEIR INFORMATION] Crest Elevation = 492.50 (ft) Weir Coefficient = 3.33 Exponential = 1. 50 [WEIR EQUATION] Q = Cw * L * H^exp [OPTIONAL ORIFICE INFORMATION] Type : Rectangular Orifice [OPTIONAL ORIFICE INFORMATION] Diameter = 0.25 (ft) Invert Elevation = 486.00 (ft) Orifice Coefficient = 0. 60 Number of Openings = 1 [ORIFICE EQUATION] Q = Co*A( (2gh) /k) ^0.5 [DEFINITIONS] Co = Orifice Coefficient A = Wetted Area, (cfs) k = 1 53 WHITTINGTON SUBDIVISION - PHASE A [CULVERT INFORMATION] Type : Circular Concrete - Square Edge with Headwall [OUTLET STRUCTURE INFORMATION] Diameter = 24 .00 (in) Invert Elevation = 486.00 (ft) Pipe Length = 80.00 (ft) Slope = 0.01 Manning's n Value = 0.01 Orifice Coefficient = 0. 60 Tailwater Elevation = 485.24 (ft) Number of Barrels = 1 [UNSUBMERGED EQUATION] H/Diam = Hc/Diam+K* (Q/ (A*Diam^0.5) ) ^M-0.5*S Coefficient K = 0.01 Coefficient M = 2.00 Q Maximum = 15.55 [SUBMERGED EQUATION] H/Diam = c* (Q/ (A*Diam^0.5) ) ^2+Y-0.5*S Coefficient c = 0.04 Coefficient Y = 0. 67 Q Minimum = 17.77 [DEFINITIONS] H = Headwater depth above inlet control section invert, (ft) Diam = Interior height of culvert barrel, (ft) He = Specific head at critical depth (dc+Vc^2/2g) , (ft) Q = Discharge, (cfs) A = Full cross sectional area of culvert barrel, (sq ft) S = Culvert barrel slope, (ft/ft) [STAND PIPE STAGE VS. DISCHARGE] Elevation Stage Weirs Orifices Stand Pipe Culvert Total (ft) (ft) (cfs) (cfs) (cfs) (cfs) (cfs) 486.00 0.00 0.00 0. 00 0.00 0. 00 0.00 486.20 0.20 0.00 0. 06 0.00 0.21 0.06 486.40 0. 40 0.00 0.12 0. 00 0.78 0. 12 486. 60 0. 60 0.00 0.16 0. 00 1. 69 0. 16 486.80 0.80 0.00 0. 19 0.00 2.85 0. 19 487 .00 1.00 0.00 0.22 0.00 4 .25 0.22 487.20 1.20 0.00 0.24 0.00 5.83 0.24 487.40 1.40 0.00 0.27 0.00 7 .50 0.27 487. 60 1. 60 0.00 0.29 0.00 9.26 0.29 487.80 1.80 0.00 0.31 0.00 11.02 0.31 488.00 2.00 0.00 0.32 0.00 12.82 0.32 488.20 2.20 0.00 0.34 0.00 14 .58 0.34 488.40 2.40 0.00 0.36 0.00 15.55 0.36 488 . 60 2. 60 0.00 0.37 0.00 17.77 0.37 54 WHITTINGTON SUBDIVISION - PHASE A 488.80 2.80 0.00 0.39 0.00 19.09 0.39 489.00 3.00 0.00 0.40 0.00 20.35 0. 40 489.20 3.20 0.00 0.41 0.00 21.53 0. 41 489.40 3.40 0.00 0.43 0.00 22. 66 0. 43 489. 60 3. 60 0.00 0.44 0.00 23.73 0.44 489.80 3.80 0.00 0.45 0.00 24 .75 0. 45 490.00 4.00 0.00 0.47 0.00 25.73 0.47 490.20 4.20 0.00 0.48 0.00 26. 68 0.48 490. 40 4.40 0.00 0.49 0.00 27.59 0.49 490.60 4 . 60 0.00 0.50 0.00 28.48 0.50 490.80 4 .80 0.00 0.51 0.00 29.33 0.51 491.00 5.00 0.00 0.52 0.00 30. 17 0.52 491.20 5.20 0.00 0.53 0. 00 30. 98 0.53 491.40 5.40 0.00 0.54 0.00 31.77 0.54 491. 60 5. 60 0.00 0.55 0.00 32.54 0.55 491.80 5.80 0. 00 0. 56 0. 00 33.29 0.56 492.00 6.00 0.00 0.57 0. 00 34.03 0.57 492.20 6.20 0.00 0.58 0.00 34 .75 0.58 492. 40 6.40 0.00 0.59 0.00 35.46 0.59 492.60 6. 60 0.00 0. 60 1.32 36. 15 1. 92 492.80 6.80 0.00 0. 61 6.88 36.83 7. 49 493.00 7.00 0.00 0. 62 14 .80 37.50 15.41 493.20 7.20 0.00 0. 63 24 .51 38. 15 25.14 493.40 7.40 0.00 0. 64 35.73 38.80 36.37 493. 60 7. 60 0.00 0. 65 48.28 39.43 39.43 493.80 7.80 0.00 0. 65 58.89 40. 06 40.06 494 .00 8.00 0.00 0. 66 68.46 40. 67 40. 67 494 .20 8 .20 0.00 0. 67 78.03 41.27 41.27 494 .40 8 .40 0.00 0. 68 83.37 41.87 41.87 494 . 60 8 . 60 0. 00 0. 69 87. 65 42.46 42.46 494 . 80 8.80 0. 00 0.70 91.73 43.04 43.04 495.00 9.00 0.00 0.70 95. 63 43. 61 43. 61 55 f WHITTINGTON SUBDIVISION - PHASE A Type : Trapezoidal Weir Name : SWM-2 WEIR [RATING CURVE LIMIT] Minimum Elevation = 493.50 (ft) Maximum Elevation = 495.00 (ft) Elevation Increment = 0. 10 (ft) [OUTLET STRUCTURE INFORMATION] Crest Length = 14 .00 (ft) Angle of Walls = 153. 6700 Crest Elevation = 493. 50 (ft) Weir Coefficient = 3.33 Exponential = 1. 50 [TRAPEZOIDAL EQUATION] Q = Cw * ( L + 0.8H * tan ( ang/2.0 ) ) * H^exp [DEFINITIONS] Cw = Weir Coefficient H = Headwater depth above inlet control section invert L = Crest lenght ang = Angle of the walls [MAXIMUM DISCHARGE] Q = 117. 03 (cfs) [WEIR STAGE VS. DISCHARGE] Elevation (ft) Stage (ft) Discharge (cfs) 493.50 0.00 0.00 493. 60 0. 10 1.51 493.70 0.20 4 .37 493.80 0.30 8 .22 493. 90 0. 40 12. 95 494 .00 0.50 18 .50 494 . 10 0. 60 24.84 494 .20 0.70 31. 97 494 .30 0.80 39.88 494 . 40 0. 90 48.56 494 .50 1.00 58 .01 494. 60 1.10 68.24 494.70 1.20 79.25 494 .80 1.30 91.05 494 . 90 1.40 103. 64 495.00 1.50 117 .03 56 WHITTINGTON SUBDIVISION - PHASE A Name: DA-O - 1.5-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 0.53 (cfs) Time to Peak (Tp) = 1057 .00 (min) Time of Base (Tb) = 1440.00 (min) Volume = 0. 51 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 491.09 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 7 Name = SWM-2 24-Hour Storage Type = User-Defined Area Maximum Storage = 79050.00 (cu ft) Maximum Discharge = 160. 64 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 57 Name = DA-0 1.5 Year Peak Flow (Qp) = 12.33 (cfs) Time to Peak (Tp) = 731.00 (min) Time of Base (Tb) = 1530. 34 (min) Volume = 1. 19 (ac-ft) Flow Multiplier = 1.00 57 WHITTINGTON SUBDIVISION - PHASE A Name: DA-O - 2-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 0.54 (cfs) Time to Peak (Tp) = 1067.00 (min) Time of Base (Tb) = 1440.00 (min) Volume = 0.52 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 491.32 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 7 Name = SWM-2 24-Hour Storage Type = User-Defined Area Maximum Storage = 79050.00 (cu ft) Maximum Discharge = 160. 64 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 58 Name = DA-O 2 Year Peak Flow (Qp) = 13.05 (cfs) Time to Peak (Tp) = 731. 00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 1.25 (ac-ft) Flow Multiplier = 1.00 58 WHITTINGTON SUBDIVISION - PHASE A Name: DA-O - 10-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 10.29 (cfs) Time to Peak (Tp) = 755.00 (min) Time of Base (Tb) = 1440. 00 (min) Volume = 1.51 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 492.88 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 7 Name = SWM-2 24-Hour Storage Type = User-Defined Area Maximum Storage = 79050.00 (cu ft) Maximum Discharge = 160. 64 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 59 Name = DA-0 10 Year Peak Flow (Qp) = 28.02 (cfs) Time to Peak (Tp) = 729.00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 2.59 (ac-ft) Flow Multiplier = 1.00 59 s • WHITTINGTON SUBDIVISION — PHASE A Name: DA-O - 100-Year - Routed Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 50.80 (cfs) Time to Peak (Tp) = 736.00 (min) Time of Base (Tb) = 1440.00 (min) Volume = 4 .30 (ac-ft) Time Step = 1.00 (min) Peak Elevation = 493.85 (ft) Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 7 Name = SWM-2 24-Hour Storage Type = User-Defined Area Maximum Storage = 79050.00 (cu ft) Maximum Discharge = 160. 64 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 71 Name = DA-0 100 Year Peak Flow (Qp) = 58.44 (cfs) Time to Peak (Tp) = 729.00 (min) Time of Base (Tb) = 1530.34 (min) Volume = 5.39 (ac-ft) Flow Multiplier = 1.00 60