DESCRIPTION

What is old is new again.  Historically, most homes used a cistern to capture and utilize rainfall for household purposes.  Rain water harvesting, like the cistern, is the next big "new" thing in the sustainable water management movement.    

It is an easy and fairly inexpensive practice for urban property owners to install with the pruchase or making of a rain barrel and connecting them to downspouts.  When it rains water is stored in the rain barrel for watering yards and gardens.  The downside to rain barrels is that they do not manage a significant amount of runoff but they are an important way to get started in water harvesting and conservation practices.  

DESIGN DETAILS

 

 

 

 

 

 

 

Rain barrels will typically capture 50 to 60 gallons. A small 8' x 10' area of roof will generate 50 gallons of water during a 1 inch of rain.  To calculate the gallons of water that is generated from 1 inch rainfall: 

measure the square footage of roof that drains to the downspout divide that number by 43,560 (converting it to % of acre) and then multiply by 27,152 gallons (the amount of water that falls on an acre from a one inch rain.)

Example:

Your rooftop is 25 foot long by 20 foot wide, which is 500 square feet.

500 S.F. / 43,560 S.F. per acre = 0.0115 acres draining to downspout

0.0115 acres x 27,152 gals per acre per inch of rain = 312 gallons of runoff to your downspout per inch of rain.

Each inch rainfall will deliver 312 gallons of runoff to your rain barrel.  Meaning it would take more than 6 50 gallon rainbarrels to capture all the rainfall draining to that one downspout.

If you have less than six barrels, be sure to have an overflow pipe that moves water away from you foundation and to ideally a rain garden that will manage the water sustainably.  

 

GALLERY