HomeMy WebLinkAboutSouthways ponds & volume control calcs.SOUTHWAYS
VOLUME CONTROL CALCULATIONS
March 16, 2018
This is a redevelopment greater than 1 acre with less than 40% site disturbance and less than
50% increase in impervious surface. Calculations are for ultimate development which may be
far into the future as Lots 1 & 2, Block 1 are being purchased by a neighbor to sit vacant and Lot
2, Block 2 is being platted with the existing house lot (Lot 1, Block 2) at this time and will not be
graded.
Area of existing impervious = 2.17 AC.
Area of ultimate proposed impervious = 2.94 AC.
Additional impervious = 0.77 AC.
0.77 AC X 43,560 SF/AC = 33,541 SF
33,541 SF X P X 1 /12 = 2795 CF of infiltration required
2795 CF/40% voids in rock = 6988 CF of rock trench
1500 LF of rock trench X 3 FT. wide X 1.56 FT. deep = 7020 CF
Shown in road and lot swales on the plan.
SOUTHWAYS
December 9, 2017
NORTH POND (AREA 1)
Drainage area = 4.49f AC. X 1800 CF per AC. = 8082 CF of wet storage required.
ELEV (FT)
AREA (SF)
VOL (CF)
931.5
11,300
>
8,900
930.5
6,500
>
3,050
930.0
5,700
>
9,300
928.0
3,600
>
5,800
926.0
2,200
27,050
SOUTH POND
(AREA 4)
Drainage area =
3.40± AC, X 1800 CF per AC.
= 6120 CF of wet storage required.
ELEV (FT)
AREA (SF)
VOL (CF)
931.5
7,400
>
5,850
930.5
4,300
>
2,000
930.0
3,700
>
5,900
928.0
2,200
>
3,500
926.0
1,300
17,250
1 3 IN. cn, ;._LLk)" I _� .
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