Videos from 2010 Envirothon
How to Estimate Your Rainwater Collection Potential:
Area to be Drained (ft2) x [Annual Rainfall (inches) ÷ 12] = cubic ft of rainwater
Cubic ft of rainwater x 7.48 = gallons of rainwater collection
For example, if Kent is considering installing gutters and rain barrels on his new 10 ft x 20 ft shed in Quinton, Virginia, then the estimated rainwater that he could collect is calculated like this:
Shed Area = 10 ft x 20 ft = 200 ft2
New Kent County Average Annual Rainfall = 43.77 inches
200 ft2 x [43.77 inches ÷ 12] = 200 x 3.65 = 729.5 cubic ft rainwater
729.5 x 7.48 = 5,456.7 gallons of potential rainwater collection
The rainwater collected is enough to water Kent’s 10 foot x 15 foot garden with over 1.5 inches of water every week for a year, more than enough to supplement the natural rainfall. At the FY2010 Utility Rates, that same amount of rainwater collected also represents an estimated savings of $26.68 in water charges and $37.07 in sewer charges, for a total of $63.75.
Just imagine the gallons that could be collected (and the money saved) if Kent harvested rainwater from the roof of his 2,000 square foot home as well!
Here are more informational links on rainwater collection:
http://rainwater.sustainablesources.com/
http://www.harvesth2o.com/faq.shtml
http://www.demesne.info/Garden-Help/Rain-Barrels.htm
