Protecting Water Quality EPA 841-F-03-003 fromURBAN RUNOFF Clean Water Is Everybody’s Business n urban and suburban areas, much The most recent National Water Quality Inventory reports that runoff of the land surface is covered I from urbanized areas is the leading source of water quality impairments by buildings and pavement, which do not allow rain and snowmelt to surveyed estuaries and the third-largest source of impairments to to soak into the ground. Instead, surveyed lakes. most developed areas rely on storm drains to carry large amounts of Did you know that because of impervious surfaces like pave- runoff from roofs and paved areas to ment and rooftops, a typical city block generates more than nearby waterways. The stormwater 5 times more runoff than a woodland area of the same size? runoff carries pollutants such as oil, dirt, chemicals, and lawn fertilizers and snowmelt remains above the The loss of infiltration from directly to streams and rivers, where surface, where it runs off rapidly in urbanization may also cause profound they seriously harm water quality. unnaturally large amounts. groundwater changes. Although To protect surface water quality and urbanization leads to great increases groundwater resources, development Storm sewer systems concentrate in flooding during and immediately should be designed and built to runoff into smooth, straight after wet weather, in many instances minimize increases in runoff. conduits. This runoff gathers speed it results in lower stream flows and erosional power as it travels during dry weather. Many native fish underground. When this runoff and other aquatic life cannot survive How Urbanized Areas leaves the storm drains and empties when these conditions prevail. Affect Water Quality into a stream, its excessive volume Increased Runoff and power blast out streambanks, Increased Pollutant Loads The porous and varied terrain of damaging streamside vegetation and wiping out aquatic habitat. These Urbanization increases the variety natural landscapes like forests, and amount of pollutants carried wetlands, and grasslands traps increased storm flows carry sediment loads from construction sites and into streams, rivers, and lakes. The rainwater and snowmelt and allows pollutants include: them to filter slowly into the ground. other denuded surfaces and eroded • Sediment In contrast, impervious (nonporous) streambanks. They often carry surfaces like roads, parking lots, and higher water temperatures from • Oil, grease, and toxic chemicals rooftops prevent rain and snowmelt streets, roof tops, and parking lots, from motor vehicles from infiltrating, or soaking, into which are harmful to the health and • Pesticides and nutrients from the ground. Most of the rainfall reproduction of aquatic life. lawns and gardens • Viruses, bacteria, and nutrients from pet waste and failing septic systems • Road salts • Heavy metals from roof shingles, motor vehicles, and other sources • Thermal pollution from dark impervious surfaces such as streets and rooftops These pollutants can harm fish and wildlife populations, kill native vegetation, foul drinking water supplies, and make recreational areas unsafe and unpleasant. Relationship between impervious cover and surface runoff. Impervious cover in a watershed results in increased surface ruunoff. As little as 10 percent impervious cover in a watershed can result in stream degradation. Managing Urban Runoff and pumped every 3 to 5 years. They should and water quality). Urban planners and also practice water conservation measures to others responsible for managing urban What Homeowners Can Do extend the life of their septic systems. and suburban areas can first identify and To decrease polluted runoff from implement pollution prevention strategies paved surfaces, households can develop Controlling Impacts from New and examine source control opportunities. alternatives to areas traditionally covered Development They should seek out priority pollutant by impervious surfaces. Porous pavement Developers and city planners should reduction opportunities, then protect materials are available for driveways and attempt to control the volume of runoff natural areas that help control runoff, and sidewalks, and native vegetation and mulch from new development by using low finally begin ecological restoration and can replace high maintenance grass lawns. impact development, structural controls, retrofit activities to clean up degraded water Homeowners can use fertilizers sparingly and pollution prevention strategies. Low bodies. Local governments are encouraged and sweep driveways, sidewalks, and roads impact development includes measures that to take lead roles in public education instead of using a hose. Instead of disposing conserve natural areas (particularly sensitive efforts through public signage, storm drain of yard waste, they can use the materials to hydrologic areas like riparian buffers and marking, pollution prevention outreach start a compost pile. And homeowners can infiltrable soils); reduce development campaigns, and partnerships with citizen learn to use Integrated Pest Management impacts; and reduce site runoff rates by groups and businesses. Citizens can help (IPM) to reduce dependence on harmful maximizing surface roughness, infiltration prioritize the clean-up strategies, volunteer pesticides. opportunities, and flow paths. to become involved in restoration efforts, In addition, households can prevent and mark storm drains with approved “don’t polluted runoff by picking up after pets and Controlling Impacts from dump” messages. using, storing, and disposing of chemicals Existing Development properly. Drivers should check their cars Controlling runoff from existing urban for leaks and recycle their motor oil and areas is often more costly than controlling antifreeze when these fluids are changed. runoff from new developments. Economic Drivers can also avoid impacts from car efficiencies are often realized through wash runoff (e.g., detergents, grime, etc.) by approaches that target “hot spots” of using car wash facilities that do not generate runoff pollution or have multiple benefits, runoff. Households served by septic systems such as high-efficiency street sweeping should have them professionally inspected (which addresses aesthetics, road safety, Related Publications Turn Your Home into a Stormwater Pollution Solution! Low Impact Development Center www.epa.gov/nps www.lowimpactdevelopment.org This web site links to an EPA homeowner’s guide to healthy This center provides information on protecting the environment habits for clean water that provides tips for better vehicle and and water resources through integrated site design techniques that garage care, lawn and garden techniques, home improvement, pet are intended to replicate preexisting hydrologic site conditions. care, and more. Stormwater Manager’s Resource Center (SMRC) National Management Measures to Control Nonpoint Source www.stormwatercenter.net Pollution from Urban Areas Created and maintained by the Center for Watershed Protection, www.epa.gov/owow/nps/urbanmm this resource center is designed specifically for stormwater This technical guidance and reference document is useful to local, practitioners, local government officials, and others that need state, and tribal managers in implementing management programs technical assistance on stormwater management issues. for polluted runoff. Contains information on the best available, economically achievable means of reducing pollution of surface Strategies: Community Responses to Runoff Pollution waters and groundwater from urban areas. www.nrdc.org/water/pollution/storm/stoinx.asp The Natural Resources Defense Council developed this inter- Onsite Wastewater Treatment System Resources active web document to explore some of the most effective www.epa.gov/owm/onsite strategies that communities are using around the nation to This web site contains the latest brochures and other resources control urban runoff pollution. The document is also available in from EPA for managing onsite wastewater treatment systems print form and as an interactive CD-ROM. (OWTS) such as conventional septic systems and alternative decentralized systems. These resources provide basic information For More Information to help individual homeowners, as well as detailed, up-to-date U.S. Environmental Protection Agency technical guidance of interest to local and state health Nonpoint Source Control Branch (4503T) departments. 1200 Pennsylvania Avenue, NW Washington, DC 20460 February 2003 www.epa.gov/nps.