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HomeMy WebLinkAboutWPO201300032 Study 2021-06-18ROUDABUSH, GALE & ASSOC.,, Inc. A PROFESSIONAL CORPORATION Serving Virginia Since i956 EMERGENCY SPILLWAY COMPARISON ORIGINAL APPROVED DEISGN VSMP AMENDMENT #2 ELEVATION 356.00' 355.93' TOP OF DAM 358.33' 358.00' SPILLWAY WIDTH 16' 40' FLOW THROUGH SPILLWAY 78.09 CFS 147.43 CFS ELEVATION HEAD 1.20' 1.05' VELOCITY THROUGH SPILLWAY 3.54 FT/S 3.34 FT/S CASCADIA SUBDIVISION Atrr..ik Name: Routing - Pond 2 100-Year Type: Reservoir: Modified Puls [HYDROGRAPH INFORMATION] Peak Flow (Qp) = 158.91 (cfs) Time to Peak (Tp) = 742.00 (min) Time of Base (Tb) = 2880.00 (min) Volume = 18.44 (ac-ft) Time Step = 2.00 (min) Peak Elevation. - 357.23 t Detention Time = NA [RESERVOIR STRUCTURE INFORMATION] Number = 2 Name = Pond 2 Storage Type = User -Defined Area Maximum Storage = 507322.44 (cu ft) Maximum Discharge = 355.06 (cfs) [INFLOW HYDROGRAPH INFORMATION] Number = 7 Name = Pond 2 Post 100-Year Peak Flow (Qp) = 261.96 (cfs) Time to Peak (Tp) = 728.00 (min) Time of Base (Tb) = 1529.85 (min) Volume = 23.92 (ac-ft) Flow Multiplier = 1.00 r 29 CASCADIA SUBDIVISION Apfr'-.,A OUTLET STRUCTURE REPORT Type : Trapezoidal Weir Name : Weir [RATING CURVE LIMIT] Minimum Elevation - 356.OD (ft) Maximum Elevation = 358.33 (ft) Elevation Increment - 0.10 (ft) [OUTLET STRUCTURE INFORMATION] Crest Length - 16.00 (ft) Angle of Walls = 157.0000 Crest Elevation = 356.10 (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 214.67 [WEIR STAGE VS. DISCHARGE] ------------------------------------------------------------------ Elevation (ft) Stage (ft) Discharge (cfs) 356.10 0.10 0.00 356.20 0.20 1.73 356.30 0.30 5.00 356.40 0.40 9.40 356.50 0.50 14.80 356.60 0.60 21.15 356.70 0.70 28.41 356.80 0.80 36.57 356.90 0.90 45.62 357.00 1.00 55.55 357.10 1.10 66.37 357.30 1.30 90.69 357.40 1.40 104.20 357.50 1.50 118.62 357.60 1.60 133.96 357.70 1.70 150.23 357.80 1.80 167.44 357.90 1.90 185.59 358.00 2.00 204.69 358.10 2.10 224.77 358.20 2.20 245.82 358.30 2.30 267.86 358.33 2.33 274.67 (cfs) 24 Weir Report Hydraflow Express Extension for AutodesM Civil 3D® by Autodesk, Inc. Pond #2 Originall Emergency Spillway Design Trapezoidal Weir Crest = Sharp Bottom Length (ft) = 16.00 Total Depth (ft) = 2.23 Side Slope (z:1) = 2.00 Calculations Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 78.09 Friday, Jun 18 2021 0()1%,& 1, A ffwo%faId Highlighted Depth (ft) = 1.20 Q (cfs) = 78.09 Area (sgft) = 22.08 Velocity (fUs) = 3.54 Top Width (ft) = 20.80 Depth (ft) Pond #2 Originall Emergency Spillway Design 3.00 2.00 1.00 MM -1.00 Depth (f',, 3.00 mix 1.00 M8 -1.00 Weir W.S. Length (ft) Pond Report Hydraflow Hydrographs Extension for Autodesk� Civil 30® by Autodesk, Inc. v2021 Friday, 06 / 18 / 2021 Pond No. 3 - Pond #2 Adjusted Pond Data Contours -User-defined contour areas. Average end area method used for volume calculation. Begining Elevation = 349.60 ft Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cult) Total storage (cult) 0.00 349.60 43,684 0 0 0.40 350.00 47,195 18,176 18,176 1A0 351.00 50,652 48,923 67,099 2.40 352.00 53,899 52,276 119,375 3.40 353.00 54,478 54,189 173,563 4.40 354.00 58,623 56,551 230,114 5.40 355.00 60,921 59,772 289,886 6.40 356.00 62,087 61,504 351,390 7.40 357.00 65,264 63,676 415,065 8.40 358.00 67,978 66,621 481,686 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in) = 30.00 3.00 Inactive Inactive Crest Len (ft) = 15.71 0.00 40.00 0.00 Span (in) = 30.00 3.00 0.00 0.00 Crest El. (ft) = 355.75 354.00 355.93 0.00 No. Barrels = 1 1 1 1 Weir Coeff. = 3.33 1.95 3.33 3.33 Invert El. (ft) = 346.57 349.60 0.00 0.00 Weir Type = Rect 75 degV Ciplti - Length (ft) = 66.00 0.00 0.00 0.00 Multi -Stage = Yes Yes No No Slope (%) = 2.83 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(inlhr) = 0.000 (by Contour) Multi -Stage = n/a Yes Yes Yes TIN Elev. (ft) = 0.00 Note: CuNort/Oririce oulfloas are analyzed under inlet(Ic) and outlet(oc) control. Weir n3en checked for orifice conditions lid) and submeMence(a), Stage / Storage / Discharge Table Stage Storage Elevation ChrA CIVB CIvC PrfRsr WrA WrB WrC WrD Exfil User Total ft cuft ft cis cfs cfs cfs cfs cfs cis cis ofs cfs cfs 0.00 0 349.60 0.00 0.00 --- - 0.00 0.40 18,176 350.00 31.53 io 0.12 is --- - 0.00 1.40 67,099 351.00 31.53 is 0.27 is -- -. 0.00 2.40 119,375 352.00 31.53 is 0.36 is -- - 0.00 3.40 173,563 353.00 31.53 is 0.43 is -- - 0.00 4.40 230,114 354.00 31.53 is 0.49 is -- - 0.00 5.40 289,886 355.00 31.53 is 0.54 is - - 0.00 6.40 351,390 356.00 31.53 is 0,59 is - - 6.54 7.40 415,065 357.00 70.00 is 0.15 is - - 53.60 s 8.40 481,686 358.00 75.08 is 0.07 is - -- 58.44 s - 0.00 - - -- 0.000 - 0.00 --- --- -- 0.124 -- 0.00 0.267 - 0.00 - - - 0.356 - 0.00 -- --- - 0.428 - 0.00 -- - - 0.489 1.95 0.00 --- --- - 2.492 11.03 2.47 --- -- -- 20.62 16.24 s 1 m -- - -- 217.42 16.57 s 96. - -- 471.77 l-- 1-11 Of k t spAU.+�7@ 357. oo' Weir Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Pond #2 Emrgency Spillway Trapezoidal Weir Crest = Sharp Bottom Length (ft) = 40.00 Total Depth (ft) = 2.07 Side Slope (z:1) = 2.00 Calculations Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 147.43 Depth (ft) 3.00 2.00 1.00 M 45M P AMt n �hl%i -k�)— Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Top Width (ft) Pond #2 Emrgency Spillway Friday, Jun 18 2021 = 1.05 = 147.43 = 44.20 = 3.34 = 44.20 Depth (ft; 3.00 2.00 1.00 M 591I6, Weir W.S. Length (ft)