HomeMy WebLinkAboutSDP200900050 CalculationsSILTSIZ
SEDIMENT BASIN SIZING
Project:Nazarene Church
Sediment Basin No.1
Date:29-Jan-10
AREA 4.43 IACRES
TOTAL REQ'D VOL.=593.0 C.Y. OR 16012.1 C.F.
Bottom of Pond Elev=390.0 Top of wet Storage and bottom of Dry
Impervious Area=41%from WRPO worksheet or 79040.62
WET STORAGE
REQ'D VOL.=8006.0 C.F.
FOR A SURFACE AREA OF 5000 S.F.at Elev=390.0
AND A TYP. SIDE SLOPE OF 2 TO 1
A wet depth of 3 ft.
yeilds a wet bottom area of 3447 s.f.at Elev=387.0
and a volume of 12670.4 c.f.OK
DRY STORAGE
REQ'D VOL.=8006.0 C.F.
FOR A BOTTOM AREA OF 5000 S.F.
AND A TYP. SIDE SLOPE OF 2 TO 1
A dry depth of 2 ft.
yeilds a dry surface area of 6195 s.f.at Elev=392.0
and a volume of 11195.4 c.f.OK
Riser dia=36.0
Riser top Elev.393.6
Orifice Elev.391.0
Orifice Dia (in.)5.0
Outfall Pipe Dia 24.0
Outfall Pipe elev.390.0
Dewatering Orifice Calculations:
h) Head (Riser elev Tess orifice elev. /2)1.3
s)= dry storage area (see above)11195.4 c.f.
Q) required orifice flow rate (S/21600)0.518 cfs
A) Required area = Q/(64.32 x h/2)"0.5 x 0.6=0.048 s.f.
d) diameter= 2 x (A/3.14159) "0.5=2.97 in. minimum req'd.
Use 6 in. flex Pipe
Bottom of Wet Area 387.0
Top of Wet Storage 390.0
Dewatering Orifice 391.0
Top of Dry Storage 392.0
Top of Riser 393.6
Top of bean l 395.0
Forebay design (0.25" per acre of impervious)
Required Volume=1647 C.F. (Imperv. Area x 0.25" / 12)
design depth=3 ft.
with side slopes of 2 1 yeilds average area of I 600
and approximate provided volume =1800 c.f.OK!
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SILTSIZ
SILT TRAP SIZING
Project:Nazarene
Silt trap No.2
Date:3- Nov -09
AREA=2.80 ACRES
TOTAL REQ'D VOL.=375.2 C.Y. OR 10130.4 C.F.
Bottom of Weir Elev=379.0
WET STORAGE
REQ'D VOL.=5065.2 C.F.
FOR A SURFACE AREA OF 1643 S.F.
AND A TYP. SIDE SLOPE OF 1 TO 1
A wet depth of 4 ft.
yeilds a wet bottom area of 1058 s.f.
and a volume of 5402.9 c.f.OK
DRY STORAGE Std. Dimensions from VESCH
REQ'D VOL.=5065.2 C.F.H Ho W
FOR A BOTTOM AREA OF 1643 S.F.1.5 0.5 2
AND A TYP. SIDE SLOPE OF 2 TO 1 2 1 2
A dry depth of 2.5 ft.2.5 1.5 2.5
yeilds a dry surface area of 2554 s.f.3 2 2.5
and a volume of 5245.8 c.f.OK 3.5 2.5 3
desired bottom length=I 40 ft.4 3 3
4.5 3.5 4
Plan Designation 5 4 4.5
Trap No.2
Drainage Area 2.80 Ac.
Length=17 ft.
Bottom of Excay. Wet Area =40 x 26 or 1058.46 S.F. at elev. 375.0 OK
Depth of Wet Storage=4 ft.
Wet Cleanout Elev.= 377.0
Bottom of Weir=48 x 34 or 1654.15 S.F. at elev. 379.0 OK
Depth of Dry Storage=2.5 ft.
Top of Berm 58 x 44 or 2578.76 S.F. at elev. 382.5 OK
H=3.5 ft.
Ho=2.5 ft.
W=25'2.x ft
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