The Chesapeake Bay watershed covers 64,000 square miles, including parts of six states, and is home to more than 17 million people. The Bay's land to water ratio (14:1) is the largest of any coastal water body in the world and is why our actions on the land have such big impacts on the Bay's health.
Over the past 30 years, cooperation between governments, businesses, and individuals has reduced many types of pollution in the Bay and its tributaries. However, one major type of water pollution continues to grow: untreated stormwater runoff from roads, roofs, and other impermeable surfaces. This growth is a result of development spreading throughout the region.
Every four years, an area about the size of Washington, D.C. (nearly 40,000 acres) is converted from field and forest to impermeable roads, parking lots, and buildings. And just one inch of rain falling on one acre of paved surface results in 27,000 gallons of runoff.
When runoff from storms sweeps across paved surfaces, it collects a mix of pollutants including trash, oil, nitrogen, phosphorous, herbicides, bacteria from pet waste, and even toxic metals such as zinc, lead, and cadmium. Pesticides have been found in 97 percent of runoff samples and at levels high enough to harm aquatic life 83 percent of the time. Flooding damage from uncontrolled runoff including flooded basements, sinkholes, and eroded roads and buildings causes $150 million per year in damages in the Susquehanna River drainage.
Fortunately, local governments can control runoff pollution with relatively simple, cost-effective practices. They include planting trees to replace natural filters removed during development and installing retention ponds to catch and filter runoff as well as roadside ditches (swales) with plants to absorb pollutants and barrels to collect rain from roofs. Developers can construct buildings with green roofs and parking lots of porous pavement. And communities can create more green spaces to allow soils to absorb rainfall.
Practices like these not only manage stormwater, they increase property values and recreational opportunities and also provide wildlife habitat and improved aesthetics. Ultimately, stormwater management can make our communities better places to live.
Jen Quinn is central Pennsylvania outreach coordinator for PennFuture, based in Harrisburg. She specializes in water quality issues.
