SW6210701_Plansheet - Misc. Detail_20210721 (3)

MAIN POOL
PERMANENT POOL WATER LEVEL 281.00
C
V #57 WASHED STONE PAD TO c
NT CICIMMFR FpnM CZMI Mir IN lull If)
CONNECT FLEXIBLE PIPE TO POND DRAIN. i
GATE VALVE SHALL REMAIN OPEN. REMOVE
SKIMMER ONCE POND IS NO LONGER USED
AS A TEMPORARY, SEDIMENT BASIN
TRASH RACK
10 yr PEAK S AGE: 283.69
TEMPORARY POOL WATER LEVEL 283.00
3
T DIA RISER TOP 283.00
4" SCH. 4� PVC TEE
INV.=281. 0
CAPPED N END
INSTALL WIRE SCREENING
ON BOTTOM OF TEE INLET•
RUNOFF CALCULATIONS:
DRAINAGE AREA TO POND: 21.0 AC.
PRE -CONSTRUCTION (10-YR STORM):
21.0 AC. (WOODS/FIELD)
C= 0.30
Q10=(0.3)(7.2 IN/HR)(21.0 AC.)=45.4 CFS
POST -CONSTRUCTION (10-YR STORM):
DRAINAGE AREA TO POND: 21.0 AC,
21.0 AC. @ 15% IMPERVIOUS
WEIGHTED C= (0.15)(0.95)+(0.85)(0.30)=0.40
Q10(POST -TO POND)=(0.40)(7.21N/HR)(21.OAC.)=60.5
Q10 OUTFLOW FROM POND=32.7 CFS
PRE DEVELOPMENT VS. POST DEVELOPMENT RUN(
45.4CFS > 32.7CFS
':`•I BOTTOM RISER=275A0 �I K'QXK/�,K/,
5' DIA. ANTI:FLOATATION BLOCK
N POND CR
NTS
MINOR ORIFICE CALCULATIONS
TOP OF RISER: 283.00
PPE: 281.00
TOTAL VOL: 68,409 cu.ft.
MIN. DEWATERING TIME: 2 days or 172800 sec.
MAX. DEWATERING TIME: 5 days or 432000 sec.
Cd: 0.60
g: 32.2 ft/s'
USING A 4" (r = 2") OUTLET PIPE, "Q" IS AS FOLLOWS:
Ho/3 = [283.00 - (281.00 + (2/12))] / 3
Ho/3: 0.61
A=3.14(2/12)A2
A=0.087 sf
Q=Cd*A*(2*g*Hol3)AO.5
68,409 cf = (0.6)(0.087)[(2*32.2"0.61)AO.5]
time
68,409 cf = 0.327
time
drawdown time=209,201 seconds=2.4 days
2"RCP 0 1.7%
TOP OF DAM 285.00 3 THE DAM STRUCTURE, INCLUDING
FRONT AND BACK EMBANKMENT
1.0' MIN. F EEBOARD
\\ SLOPES, OF THE POND SHALL BE
EMERGENCY SPILLWAY 283.00 VEGETATED WITH NON -CLUMPING
TURF GRASS
(HYBRID BERMUDA OR CENTIPEDE)
CORE TRENCH (MIN 4' DEEP)
ALONG ENTIRE LENGTH OF POND DAM
RISER BUOYANCY CALCULATIONS
INSIDE DIAMETER: 36" = 3.0 ft
WALL THICKNESS: 4" = 0.33 ft
TOP ELEVATION: 283.00
INVERT ELEVATION: 275.00
Yconcrete: 1501b/cu ft
Ywater: 62.4 Ib/cu.ft.
DISPLACEMENT (d) VOLUME AND WEIGHT
Vd = (3.14159) (2.5)A2 (h) + (3.14159) (1.83)A2 (8.00)
Vd = (19.63h + 84.17) cu.ft:
Wd = 62.409.63h + 84.17)
Wd = (1224.9h + 5252.2) lb
CONCRETE (c) VOLUME AND WEIGHT
Vc = (3.14159) (1.83)A2 (8.00) - (3.14159) (1.5)A2 (8.00) + (3.14159) (2.5)^2 (h)
Vc = 09.63h + 27.62) cu.ft.
We = 15009.63h + 27.62)
We = (2944.5h + 4143.0) lb
REQUIRED BUOYANCY PREVENTION FACTOR = 1.1
Wc= 1.lWd
(2944.5h + 4143.0) = 1.1(1224.9h + 5252.2)
h =1.02 ft.
USE 1.1' SASE THICKNESS
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