Reducing Runoff (Washington, DC)
When rain falls on natural areas, it slowly soaks into the ground where it recharges groundwater supplies that eventually feed some rivers and streams. In urban areas, however, large amounts of pavement cause rainwater to run off roads, driveways, and sidewalks quickly. Instead of seeping into the ground, this water is carried through storm drains and ditches which discharge directly to local rivers and streams — this creates high flows during rain events, but can lead to low flows after the rain has passed. In areas where rivers and streams depend on groundwater to replenish their water supplies, this can mean overall lower water levels.
Viewer Tip: One study estimates thatDC loses between23.8 and55.6 billion gallons of water that would normally soak into the ground each year due to runoff from paved surfaces in the city. You can help reduce runoff at homeby allowing water to soak into the ground on your property, instead of running off into a street, storm drain, or creek. Make sure that home gutters and downspouts are directed towards grassy areas instead of pavement. You might also consider adding a rain barrel to your home, which connects to a downspout and collects rainwater for later uses, such as outdoor watering or car washing.
Seasons: Spring, Summer, Fall, Winter
(Sources: American Rivers, Natural Resources Defense Council, and Smart Growth America. “Paving Our Way to Water Shortages: How Sprawl Aggravates Drought.” Available from: http://www.smartgrowthamerica.org/PavingOurWay.pdf; EPA Office of Wetlands, Oceans, and Watersheds (Patty Scott). Watershed Tips, April 11, 2005)
