Rain is Natural, But Run-Off is Not

by Andrea Bennett

Potted daylilies and ivy in a parking area help transform an impermeable surface into one that captures rainwater.

Potted plants in a parking area help transform an impermeable surface into one that captures rainwater.

While we know that forests, meadows, and other plantings help slow the flow of rainwater and filter out pollutants, some towns (including mine) still have zoning laws prohibiting homeowners from replacing impermeable surfaces with vegetation.

These ordinances may not make the most sense from an environmental standpoint, but they can inspire homeowners to get creative about adapting impervious surfaces around the house to absorb rainfall and prevent polluted run-off.

For example, in my case, I realized that putting plants on top of an impermeable surface, mimicking more natural ground cover, could make a real difference. The daylilies and ivy we now have in our parking area are helping to soak up rain before it becomes run-off.

When rain falls onto impervious surfaces that have pet waste, leaked oil, and lawn chemicals, they transport that polluted run-off to local creeks and rivers. By keeping the rain from contacting the pollution on land, or slowing down the movement of polluted stormwater, we give our local waterways a better chance of staying healthy.

The Virginia Cooperative Extension has crunched the numbers on how much runoff a medium-size house and lot in Virginia could generate, and they might surprise you.

They found that a 1,600 square foot roof and 750 square feet of driveway and sidewalks results in a total of 2,350 square feet of impervious surface. With just a half-inch of rain, more than 700 gallons of water would run off – enough to fill about 15 bathtubs! During a bigger or longer storm event, even more rain would turn to run-off.

There are even more ways to keep rain from turning into polluted run-off. Around your home, you could build a rain garden; install permeable surfaces; sweep your driveways and walkways; pick up litter; and fix oil and antifreeze leaks from automobiles.

As for me, I plan to install a rain barrel to help capture rainwater to reuse in my yard. Keep an eye out for local rain barrel workshops in your town: these workshops explain how to construct a rain barrel from a plastic 55-gallon drum, so you can use the water it collects to water plants.

What else can you do around your home to make sure rain doesn’t turn into polluted run-off? Let us know in the comments.


About the Author: Andrea Bennett is a biologist with EPA. Andrea enjoys birding, kayaking and playing the mandolin and she is a member of her local watershed protection team.



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