THE STORMWATER CALCULATION PROCESS - Low Impact Development and Sustainable Stormwater Management - page 201

WORKSHEET 9. CAPTURE / REUSE WATER BALANCE

PROJECT

SUB-BASIN:

Design
Storage
(gal): 10000

Supply

Demand

Runoff
Coefficient
of Capture/
Reuse
Area

Average
Monthly
Runoff
Volume
(gal)

Monthly
Interior
Water
Demand
(gal)

Monthly
Total
Water
Demand
(gal)

Monthly
Irrigation
Demand
(gal)

Average
Rainfall
(in)

Capture/
Reuse
Area (sf)

Storage
at Start of
Month
(gal)

Storage
at End of
Month
(gal)

Deficit
(gal)

Month Begin

Month
(gal)

End
Month
(gal)

Overflow
Volume
(gal)

January
February

2 20000 0.9 22440 0 5000 5000 0 10000 10000 10000 10000 17440

2
1
1
0.5
0.5
0.1
0.5
1

20000
20000
20000
20000
20000
20000
20000
20000

0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9

22440
11220
11220
5610
5610
1122
5610
11220

0 5000

5000
5000
5000
5000
5000
5000
5000

5000
5000
15000
15000
15000
15000
15000
15000

0
0
3780
9390
9390
13878
9390
3780

10000
10000
10000
6220
− 3170
− 9390
− 13878
− 9390

10000
10000
10000
6220
0
0
0
0

10000
10000
6220
− 3170

10000
10000
6220

17440
6220
0

0

March

April 10000

10000 0 0

0
0
0
0

May

June 10000 − 9390

− 13878
− 13878
− 3780

0
0
0
0

10000

July

August 10000

September 10000

October 1 20000 0.9 11220 0 5000 5000 0 − 3780 0 6220 6220 2440

November 2

2

20000
20000

0.9
0.9

22440
22440

0 5000

5000

5000
5000

0
0

6220
10000

6220
10000

10000
10000

10000
10000

17440
17440 December 0

RUNOFF
Total
Runoff
Volume
(gal)
Overflow
Volume
(gal)
Runoff
Volume
Captured
(gal)

152592

78420

74172

% of
Runoff
Captured
WATER
SUPPLY

49%

Total
Demand
(gal)
Runoff
Volume
Captured
(gal)

120000

74172

% Supply
Met

62%