Make use of rooftop runoff
By Terasa M. Lott, Water Resources Agent, Clemson Extension
Have you ever stood outside while it’s raining and watched the water flowing off your roof? Science geeks like me do crazy things like that (and enjoy it). If standing out in the rain isn’t your thing, you could simply peer out the window. The point of watching the rain is to see just how much water flows off the roof.
It might not look like much but it sure adds up. We can use some simple math to determine the quantity of water flowing off your roof over the course of a year. Bear with me while I explain the calculations. Each square foot of roof space generates .62 gallons of runoff in a 1-inch rainstorm. That means a 1,000 square foot roof generates 620 gallons of runoff per 1-inch of rain. Florence’s average yearly rainfall is 46 inches so the yearly runoff from your roof would be a whopping 28,520 gallons of water!
You can make use of that water by storing it for later use. This practice, known as rainwater harvesting, has numerous benefits. From a homeowner perspective, you have a free source of water that doesn’t



Set of painted rain barrels from the Florence Cultural Garden on Dargan Street, beside Wholly Smokin’.
contain chlorine. From an environmental perspective, rainwater harvesting protects our local water resources that we enjoy for fishing, swimming, and other recreational activities.
Two years ago, the Florence Darlington Stormwater Consortium initiated the Rain Barrel Art Review as unique way to raise awareness about the benefits of rainwater harvesting. This year, eleven school and community groups across Florence and Darlington counties are painting rain barrels that will later be installed at school, libraries, churches, parks, or community centers. Finished barrels will be displayed on April 18 at the Earth Day Festival at Kalmia Gardens of Coker College. You can help determine the winners by attending the festival and voting for your favorite barrel. The Earth Day Festival takes place from 10:00 a.m. – 2:00 p.m. and with crafts, music, falconry, beekeeping, tours, games, and a duck cup race, there’s sure to be something for everyone to enjoy.
For information on building your own rain barrel, Clemson Extension offers a Rainwater Harvesting for Homeowners manual which can be purchased at shopping.clemson.edu or is available as a free download from the Carolina Clear Toolbox at www.clemson.edu/carolinaclear/cc_toolbox.
Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political beliefs, sexual orientation, marital or family status and is an equal opportunity employer.