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Home My WebLink About08.08.13 Calculation of Peak Run off using retional MethodCALCULATION OF A' PEAK RUNOFF USING RATIONAL METHOD Project Title: Catchment ID: TLT Services Contractor Yard 25 Year Event - Historic I. Catchment Hydrologic Data Catchment ID = H -1 Area = Percent Imperviousness = NRCS Soil Type = 5.12 Acres 1.00 % B A, B, C, or D II. Rainfall Information Design Storm Return Period, Tr = Cl = C2= C3= P1= I (inch/hr) = C1 * P1 !(C2 + Td)AC3 2 years 28.50 10.00 0.786 1.10 inches (input return period for design storm) (input the value of C1) (input the value of C2) (input the value of C3) (input one -hr precipitation- -see Sheet "Design Info ") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = Overide Runoff Coefficient, C = 5 -yr. Runoff Coefficient, C -5 = Overide 5 -yr. Runoff Coefficient, C = 0.02 (enter an overide C value If desired, or leave blank to accept calculated C.) 0.08 (enter an overide C -5 value If desired, or leave blank to accept calculated C -5.) Jllustratior! LEGEND 0 Beginning Flow Direction Catchment Boaniary NRCS Land Type Heavy Meadow Tillage/ Field Short Pasture/ Lawns Nearly Bare Ground Grassed Swales/ Waterways Paved Areas 8 Shallow Paved Swales (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach ID Overland Slope S ft/ft input Length L ft input 5-yr Runoff Coeff C -5 output NRCS Convey- ance input Flow Velocity V fps output Flow Time Tf minutes output 0.0700 50 0.08 N/A 0.12 6.86 1 0.0700 400 2 0.1700 30 3 0.0300 275 0.0700 135 5 Sum 890 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = Rainfall Intensity at Regional Tc, I = Rainfall Intensity at User- Defined Tc, I = 2.67 inch /hr 2.50 inchlhr 2.67 inch/hr TLT Services Drainage Historic 25yr_UD- Rational v1.02a.xls, Tc and PeakQ 10.00 2.65 2.52 10.00 4.12 0.12 10.00 1.73 2.65 10.00 2.65 0.85 Computed Tc = Regional Tc = User- Entered Tc Peak Flowrate, Op = Peak Flowrate, Qp = Peak Flowrate, Qp = 13.00 14.94 13.00 0.33 cfs 0.31 cfs 0.33 cfs 8/8/2013, 12:53 PM CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Protect Title: Catchment ID: TLT Services Contractor Yard 100 Year Event - Historic 1. Catchment Hydrologic Data Catchment ID = H -1 Area = 5.12 Acres Percent Imperviousness = 1.00 % NRCS Soil Type = B A, B, C, or D 11. Rainfall Information Design Storm Return Period, Tr = Cl C2= C3= P1= 1 (inch/hr) = C1 ' P1 !(C2 + Td)"C3 2 years 28.50 10.00 0.786 1.43 inches (input return period for design storm) (input the value of C1) (input the value of C2) (input the value of C3) (input one -hr precipitation - -see Sheet "Design Info ") Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = Overide Runoff Coefficient, C = 5 -yr. Runoff Coefficient, C -5 = Overide 5 -yr. Runoff Coefficient, C = 0.02 (enter an overide C value if desired, or leave blank to accept calculated C.) 0.08 (enter an overide C -5 value If desired, or leave blank to accept calculated C -5.) illustration LEGEND 0 Begirming Flow Direction Cotehrnent Boun!*ry NRCS Land Typo Heavy Meadow Tillage! Field Short Pasture! Lawns Nearly Bare Ground Grassed Swales/ Waterways Paved Areas & Shallow Paved Swales (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach ID Overland Slope S ftlft input Length L ft input 5 -yr Runoff Coeff C -5 output NRCS Convey- ance input Flow Velocity V fps output Flow Time Tf minutes output 0.0700 50 0.08 N/A 0.12 6.86 1 2 3 4 0.0700 0.1700 0.0300 0.0700 400 30 275 135 5 Sum 890 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = Rainfall Intensity at Regional Tc, I = Rainfall Intensity at User- Defined Tc, 1= 3.47 inchlhr 3.25 inchlhr 3.47 inch/hr TLT Services Drainage Historic 100yr UD- Rational v1.02a. ds, Tc and PeakQ 10.00 2.65 2.52 10.00 4.12 0.12 10.00 1.73 2.65 10.00 2.65 0.85 Computed Tc = Regional Tc = User- Entered Tc Peak Flowrate, Qp = Peak Flowrate, Qp = Peak Flowrate, Qp = 13.00 14.94 13.00 0.42 cfs 0.40 cfs 0.42 cfs 8/8/2013, 12:52 PM 0.08 0.02 CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Titre: Catchment ID: TLT Services Contractor Yard 2 Year Event - Proposed I. Catchment Hydrologic Data Catchment ID = Area = Percent Imperviousness = NRCS Soil Type = P -1 5.12 1.00 11. Rainfall Information Design Storm Return Period, Tr = C1 = C2= C3= P1= Acres cyo A, B, C, or D I (inch /hr) = C1 " P1 / {C2 + Td } ^C3 2 28.50 10.00 0.786 0.56 years inches (input return period for design storm) (input the value of C1) (input the value of C2) (input the value of C3) (input one -hr precipitation - -see Sheet "Design Info ") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = Overide Runoff Coefficient, C = 5 -yr. Runoff Coefficient, C -5 = Overide 5 -yr. Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) (enter an overide C -5 value if desired, or leave blank to accept calculated C -5.) Illustration LEGEND 0 Beginning Flaw Dim tton Catchment Boundary NRCS Land Type Heavy Meadow Tillage/ Field Short Pasture! Lawns Nearly Bare Ground Grassed Swales/ Waterways Paved Areas & Shallow Paved Swales (Sheet Flow) Conveyance 2.5 5 1 7 10 15 20 Calculations: Reach ID Overland Stops 5 ft!ft input Length L ft input 5 -yr Runoff Coeff C -5 output NRCS Convey- ance input Flow Velocity V fps output Flow Time Tf minutes output 0.0700 50 0.08 N/A 0.12 6.86 2 3 4 5 0.0700 0.1700 0.0300 0.0500 0.0100 Sum 400 30 150 250 120 1,000 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = Rainfall Intensity at Regional Tc, I = Rainfall Intensity at User - Defined Tc, I = 1.28 1.25 1.28 inch /hr inch /hr inch /hr TLT Services Drainage Proposed 2yr UD- Rational v1.02a.)ds, Tc and PeakQ 10.00 2.65 2.52 10.00 4.12 0.12 10.00 1.73 1.44 10.00 2.24 1.86 10.00 Computed Tc = Regional Tc = User- Entered Tc = 1.00 Peak Flowrate, Qp = Peak Flowrate, Qp = Peak Flowrate, Qp = 2.00 14.81 15.56 14.81 0.16 0.15 0.16 cfs cfs cfs 8/8/2013, 12:51 PM CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: Catchment ID: TLT Services Contractor Yard 25 Year Event - Proposed 1. Catchment Hydrologic Data Catchment ID = P -1 Area = Percent Imperviousness = NRCS Soil Type = 5.12 Acres 1.00 % B A, B, C, or D 11. Rainfall Information Design Storm Retum Period, Tr = C1 = C2= C3= P1= 1 (inchlhr) = C1 * P1 1(C2 + Td)AC3 2 years 28.50 10.00 0.786 1.10 inches (input return period for design storm) (input the value of C1) (input the value of C2) (input the value of C3) (input one -hr precipitation- -see Sheet "Design Info ") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.02 Overide Runoff Coefficient, C = 5 -yr. Runoff Coefficient, C -5 = 0.08 Overide 5 -yr. Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.) (enter an overide C -5 value If desired, or leave blank to accept calculated C -5.) Illustration LEGEND 0 Beg Flow Direction Catchment BounL ry NRCS Land Type Heavy Meadow Tillage/ Field Short Pasture/ Lawns Nearly Bare Ground Grassed Swalos/ Waterways Paved Areas & Shallow Paved Swages (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach ID Overland Slope s ft/ft input 0.0700 Length L ft input 50 5•yr Runoff Coeff C -5 output 0.08 NRCS Convey- ance input NIA Flow Velocity V fps output 0.12 Flow Time Tf minutes output 6.86 1 2 3 4 5 0.0700 0.1700 0.0300 0.0500 0.0100 Sum 400 30 150 250 120 1,000 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = Rainfall Intensity at Regional Tc, I = Rainfall Intensity at User - Defined Tc, I = 2.51 2.45 2.51 inch/hr inch/hr inchlhr TLT Services Drainage Proposed 25yr_UD- Rational v1.02a. ds, Tc and Peak() 10.00 2.65 2.52 10.00 4.12 0.12 10.00 1.73 1.44 10.00 2.24 1.86 10.00 1.00 2.00 Computed Tc Regional Tc = User- Entered Tc Peak Flowrate, Qp v Peak Flowrate, Qp = Peak Flowrate, Qp = 14.81 15.56 14.81 0.31 0.30 0.31 cfs cfs cfs 8/8/2013, 12:51 PM CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: Catchment ID: TLT Services Contractor Yard 100 Year Event - Pro•osed I. Catchment Hydrologic Data Catchment ID = P -1 Area = Percent Imperviousness = NRCS Soil Type = 5.12 Acres 1.00 % 8A,8,C,orD 11. Rainfall Information Design Storm Return Period, Tr = C1 = C2= C3= P1= (inch/hr) = C1 ' P1 /(C2 + Td)AC3 2 years 28.50 10.00 0.786 1.43 inches (input return period for design storm) (input the value of C1) (input the value of C2) (input the value of C3) (input one -hr precipitation - -see Sheet "Design Info ") III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = 0.02 Overide Runoff Coefficient, C = 5 -yr. Runoff Coefficient, C -5 = 0.08 Overide 5 -yr. Runoff Coefficient, C (enter an overide C value if desired, or leave blank to accept calculated C.) (enter an overide C -5 value if desired, or leave blank to accept calculated C -5.) JllustratIort EL GGEND 0 Beginning Flow Direction Catchment Boundary NRCS Land Type Heavy Meadow Tillage! Field Short Pasture/ Lawns Nearly Bare Ground Grassed Swales/ Waterways Paved Areas & Shallow Paved Swales (Sheet Flow) Conveyance 2.5 5 7 10 15 20 Calculations: Reach ID Overland Slope s ft/ft input Length L ft input 5 -yr Runoff Coeff C -5 output NRCS Convey- ance input Flow Velocity V fps output Flow Time Tf minutes output 0.0700 50 0.08 N/A 0.12 6.86 1 2 3 4 5 0.0700 0.1700 0.0300 0.0500 0.0100 400 30 150 250 120 Sum 1,000 IV. Peak Runoff Prediction Rainfall Intensity al Computed Tc, I Rainfall Intensity at Regional Tc, I = Rainfall Intensity at User- Defined Tc, I = 3.27 inch/hr 3.19 inch/hr 3.27 inch/hr TLT Services Drainage Proposed 100yr_UD- Rational v1.02a. ds, Tc and PeakQ 10.00 2.65 2.52 10.00 4.12 0.12 10.00 1.73 1.44 10.00 2.24 1.86 10.00 1.00 2.00 Computed To = Regional Tc = User- Entered Tc = Peak Flowrate, Qp = Peak Flowrate, Qp = Peak Flowrate, Qp = 14.81 15.56 14.81 0.40 cfs 0.39 cfs 0.40 cfs 8/8/2013, 12:50 PM 0.08 0.02 CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD Project Title: Catchment ID: TLT Services Contractor Yard 2 Year Event - Historic I. Catchment Hydrologic Data Catchment ID = Area = Percent Imperviousness = NRCS Soil Type = H -1 5.12 1.00 B II. Rainfall Information Design Storm Return Period, Tr = C1 = C2= C3= P1= Acres pro A, B, C, or D (Inch /hr) = C1 * P1 /(C2 + Td)AC3 2 28.50 10.00 0.786 0.56 years inches {input return period for design storm) (input the value of C1) (input the value of C2) (input the value of C3) (input one -hr precipitation - -see Sheet "'Design Info°) III. Analysis of Flow Time (Time of Concentration) for a Catchment Runoff Coefficient, C = Overide Runoff Coefficient, C = 5 -yr. Runoff Coefficient, C -5 = Overide 5 -yr. Runoff Coefficient. C = (enter an overide C value if desired, or Reave blank to accept calculated C.) (enter an overide C-5 value if desired, or leave blank to accept calculated C -5.) Illustration LEGEND 0 Beginning Flow Direction Catchment Boundary NRCS Land Type Heavy Meadow Tillage/ Field Short Pasture/ Lawns Nearly Bare Ground_ Grassed Swales/ Waterways Paved Areas & Shallow Paved Swales (Sheet Flow) _ Conveyance 2.5 5 7 10 15 20 Calculations: Reach ID Slope S ftift input Length L ft input 5 -yr Runoff Coeff C -5 output NRCS Convey- ance input Flow Velocity V fps output Flow Time Tf minutes output Overland 0.0700 1 0.0700 2 0.1700 3 0.0300 4 0.0700 5 50 400 30 275 135 0.08 N/A 0.12 6.86 Sum 890 IV. Peak Runoff Prediction Rainfall Intensity at Computed Tc, I = Rainfall Intensity at Regional Tc, I = Rainfall Intensity at User - Defined Tc, I = 1.36 inch/hr 1.27 inch/hr 1.36 inchlhr TLT Services Drainage Historic 2yr_UD- Rational v1.02a.t4s, Tc and PeakO 10.00 2.65 2.52 10.00 4.12 0.12 10.00 1.73 2.65 10.00 2.65 0.85 Computed Tc = Regional Tc = User - Entered Tc = Peak Flowrate, Qp = Peak Flowrate, Qp = Peak Flowrate. Qp = 13.00 14.94 13.00 0.17 0.16 0.17 cfs cfs cfs 8/8/2013, 12:53 PM