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HomeMy WebLinkAboutWPO200302301 Stormwater Mgmt Facility 1 - Calculations 2004-01-15 (2) • _ r '%%j k.EV ON, /5,i0611 l ; 3.14 1992 TEMPORARY SEDIMENT BASIN DESIGN DATA SHEET (with or without an emergency spillway) Project 12 (LO1\ `'i DI t.9Yn u1) +-We\CC.-VS' Basin # J.- Location frôc ' s is Q o - 5 k, Ackj'i ceo4- al Total area draining to basin: acres. Basin Volume Design Wet Storage: 1. Minimum required volume = 67 cu. yds. x Total Drainage Area (acres). 67 cu. yds. x 3.7 acres - 1,Sa cu., yds. 2. Available basin volume . cu. yds. at elevation 524,. . (From storage - elevation curve) 3. Excavate 01 ,cu. yds. to obtain required volume*. * Elevation'corresponding to required volume = invert of the dewatering orifice. 4. Available volume before cleanout required. . 33 cu. yds. x ''; 7 acres = 7 r�' cu. yds. 5. Elevation corresponding to cleanout level = 516 a 5. . (From Storage - Elevation Curve) 6. Distance from invert of the dewatering orifice to cleanout level = 1•-5 ft. (Min. = 1.0 ft.) Dry Storage: 7. Minimum required volume = 67 cu. yds. x Total Drainage Area (acres). 67 cu. yds. x Al acres = ing cu. yds. III - 112. %779,14 �3 2.00,1 1992 3.14 8. Total available basin volume at crest of riser* = 12,000 cu. yds. at elevation S a3,a5. (From Storage - Elevation Curve) * Minimum = 134 cu. yds./acre of total drainage area. 9. Diameter of dewatering orifice = 2 in. 10. Diameter of flexible tubing = I 0 in.(diameter of dewatering orifice plus 2 inches). Preliminary Design Elevations 11. Crest of Riser = 75 Top of Dam = S 3.$.5 Design High Water = Upstream Toe of Dam = S 12 .O Basin Shape 12. Length of Flow L , Effective Width We If > 2, baffles are not required If < 2, baffles are required Runoff 13. Q2 = cfs (From Chapter 5) 14. Q25 = cfs (From Chapter 5) Principal Spillway Design 15. With emergency spillway, required spillway capacity Qp = Q2 = cfs. (riser and barrel) Without emergency spillway,required spillway capacity Qp = Q25 = 131, cfs. (riser and barrel) III - 113 1992 3.14 16. With emergency spillway: Assumed available head (h) = ft. (Using Q2) h = Crest of Emergency Spillway Elevation - Crest of Riser Elevation Without emergency spillway: Assumed available head (h) = (©.," ft. (Using Q25) h = Design High Water Elevation - Crest of Riser Elevation 17. Riser diameter (D) .= 6 O in. Actual head (h) = ft. (From Plate 3.14-8.) Note: Avoid orifice flow conditions. 18. Barrel length (1) = t2 0 . ft. Head (H) on barrel through embankment = ft. (From Plate 3.14-7). 0 19. Barrel diameter = 3 6 in. (From Plate 3.14-B [concrete pipe] or Plate 3.14-A [corrugated pipe]). 20. Trash rack and anti-vortex device A it Diameter = J inches. Height = inches. (From Table Emergency Spillway Design 21. Required spillway capacity Qe = Q25 - Qp = cfs. 22. Bottom width (b) = ft.; the slope of the exit channel (s) _ ft./foot; and the minimum length of the exit channel (x) = ft. J (From Table 3.14-C). • III - 114 1992 3.14 Anti-Seep Collar Design 23. Depth of water at principal spillway crest (Y) = ft: Slope of upstream face of embankment (Z) = :1. Slope of principal spillway barrel (Sb) =-._ % Length of barrel in saturated zone (La) = ft. 24. Number of collars required = dimensions = (from Plate 3.14-12). Final Design Elevations 25. . Top of Dam = 529. Design n High Water = S 2-7.3 6.0-Y 19 Emergency Spillway Crest = _ Principal Spillway Crest = 5.2-3175 Dewatering Orifice Invert = :52 , 0 Cleanout Elevation = 5!6,5 Elevation of Upstream Toe'of Dam or Excavated Bottom of "Wet Storage Area" (if excavation was performed) = SI Z I III - 115 1992 3.14 Anti-Seep Collar Design �� y 23. Depth of water at principal spillway crest ( = 1-1y_ ft. ,1/ COI g Slope of upstream face of embankment ' :1. 56e, tio Slope of principal spillway rre % Length of barrel in saturated e s) I QC) ft. 24. Number of collars required = dimensions = - X 7 (from Plate 3.14-12). Final Design Elevations 25. Top of Dam = 5)1. -S High Design g h Water = 5 77.3 600 YE41') Emergency Spillway Crest = Principal Spillway Crest = 5.3 3.�l.7 , Dewatering Orifice Invert = 520, 0 Cleanout Elevation = 51 8 i Elevation of Upstream Toe of Dam or Excavated Bottom of "Wet Storage Area" (if excavation was performed) = 5) .1 .•0 III - 115 T,. • ' HOLLYMEAD TOWN CENTER-SWM1 • SEDIMENT BASIN CONDITIONS [DISCHARGE INFORMATION] Name: SWM1-Sed. Basin Structure [RESERVOIR STAGE STORAGE/DISCHARGE] Elevation Stage Area Storage Discharge (ft) (ft) (sq ft) (cu ft) (cfs) 511.0000 0.0000 0.0000 0.0000 0.00 511.5000 0.5000 7738.0000 1934.5000 0.00 512.0000 1.0000 15476.0000 7738.0000 0.00 512.5000 1.5000 - 16418.2500 15711.5625 0.00 513.0000 2.0000 17360.5000 24156.2500 0.00 513.5000 2.5000 18302.7500 33072.0625 0.00 514.0000 3.0000 19245.0000 42459.0000 0.00 514.5000 3.5000 20260.2500 52335.3125 0.00 515.0000 4.0000 21275.5000 62719.2500 0.00 515.5000 4.5000 22290.7500 73610.8125 0.00 516.0000 5.0000 23306.0000 85010.0000 0.00 516.5000 5.5000 24391.2500 96934.3125 wEr 0.00 517.0000 6.0000 25476.5000 109401.2500 ,,. `•� 1.10 517.5000 6.5000 26561.7500 122410.8125 fa, ' 3.58 518.0000 7.0000 27647.0000 135963.0000 5.53 518.5000 7.5000 28802.5000 150075.3750 6.93 519.0000 8.0000 29958.0000 164765.5000 8.09 519.5000 8.5000 31113.5000 180033.3750 9.10 520.0000 9.0000 32269.0000 195879.0000 10.01 520.5000 9.5000 33471.5000 212314.1250 10.85 521.0000 10.0000 34674.0000 229350.5000 11.63 521.5000 10.5000 35876.5000 246988.1250 Dx, 12.35 522.0000 11.0000 37079.0000 265227.0000 320 Gl 13.04 522.5000 '11.5000 38343.0000 284082.5000 14.59 523.0000 12.0000 39607.0000 303570.0000 20.17 523.5000 12.5000 40871.0000 323689.5000 28.05 524.0000 13.0000 42135.0000 344441.0000 37.63 524.5000 13.5000 43441.5000 365835.1250 48.64 525.0000 14.0000 . 44748.0000 387882.5000 60.90 525.5000 14.5000 45921.2500 410549.8125 89.24 526.0000 15.0000 47094.5000 433803.7500 99.97 Maximum Storage = 433803.7500(cu ft) Maximum Discharge = 99.97.(cfs) Rivanna Engineering&Surveying,PLC Page 3 (434)984-1599