SW4240501_Design Calculations_20240819 (4)

WET POND#1 DESIGN WORKSHEET
Project: Reserve at Old Hollow
Date: 8/15/2024
Drainage Area(A)= 4.14 Ac.
Built-Upon Area= 2.14 Ac.
Design Volume(DV):
IA=Built-Upon/Drainage= 51.7%
Rv=0.05+0.9 x IA= 0.515
Design Volume(DV)= 3630 x RD x Rv x A= 7,740 cu ft
Main Pool Design:SA/DA Table
Average Depth: 3 ft
Interpolated SA/DA Ratio: 1.84
Surface Area(SA)=
SA/DA*DA/100*43,560 sqft= 3318 sq ft
Provided SA(Elevation=962)= 5,386 sq ft
Drawdown Time:
Cd=Coefficient of Discharge= 0.6 (0.6 typical)
Orifice Diamter(in)= 1.25 in
A=Area of Orifice= 0.00852 sqft
Depth of Design Volume= 1.1 ft
Ho=Depth of Water Quality Volume/3 0.366666667 ft
Q=Cd*A(2*g*H0)1/2=
0.0248 cfs
Drawdown Time=DV/Q/3600/24= 3.6 days
Average
Elevation Area Area Volume
958 86
FOREBAY SEDIMENT STORAGE 958-959 166 166
959 246
959 246
500 499.5
FOREBAY 959-962 960 753
1,113 2225
962 1472
TOTAL 2724.5 (15.34%permanent pool)
955 1,135
SEDIMENT STORAGE 955-956 1,339 1338.5
956 1542
1542
1,943 3886
958 2344
PERMANENT POOL 956-962 (VEGETATED 2,814 5628
SHELF 961-962) 960 3284
3,596 3596
961 3908
4,647 4647
962 5,386
TOTAL 17757
962 6,858
7,326 7,326
DESIGN VOLUME 962-963.1 963 7,794
7,849 785
963.1 7,904
TOTAL 8,111
WATER QUANTITY 963.1-966(TOP OF DAM) 963.1 7,904 J
EMERGENCY SPILLWAY-964 9,705 28,144
966 11,506