permaculture

["Steve Diver" <steved@ncatark.uark.edu>]

Some useful figures and calculations for rain water catchment: 

1st
Inches rainfall x Square feet of surface area = Amount

2nd 
Amount x 0.625 Factor 

Factor = (12-inch depth per cubic foot and 7.5 gallons per cubic 
foot of  water) or (7.5 divided by 12 = 0.625)

Example: 

30-inches per year is equivalent to 18.75 gallons per of water 
collected from each square foot of surface area.  

30-inches of rainfall collected from the roof of a 1,600 square 
foot home = 30,000 gallons water 

30-inches of rainfall collected from the roof of a 2,500 square
foot home = 46,875 gallons water 

Storage tank capacity will depend on total rainfall, surface area 
collected, seasonal rainfall patterns, and seasonal water use patterns.

If ya'll got any other handy calculations and figures, please 
share them. 

Steve Diver 


--
steved@ncatark.uark.edu