Most Americans don't know what a watershed is. Do you?

A couple weekends ago I bundled up and took a boat tour of the Anacostia River with Jim Connolly, executive director of the Anacostia Watershed Society.

The Anacostia is not only Washington’s forgotten river, separating the city’s poorest section from the rest of D.C., but it’s heavily polluted. According to the Chesapeake Bay Foundation, the Anacostia is the area’s greatest source of pollution to the Bay, including millions of gallons of raw sewage. Today, there are a number of groups, including the Anacostia Watershed Society, that are working to clean up the river. But it’s still in bad shape.

One of the things that stuck with me after Connolly’s tour is that most Americans don’t know the definition of a watershed--which is clearly an obstacle in educating the public about clean water.

According to the Environmental Protection Agency, a watershed is the area of land where all the water that is under it or drains off it goes into the same place. The EPA says there are 2,110 watersheds in the continental United States. And we all live in a watershed, because when it rains, the water collects and eventually flows into a stream, river, lake, wetland or the ocean. Our daily actions within these watersheds—whether it’s pesticides on our front lawns, cigarette butts tossed on the sidewalk or tree removal for development—can be detrimental to our bodies of water.

One of the threats to the watershed is stormwater runoff. In urban areas like Washington, stormwater flows over paved roads and collects sediment, oil and metals that are then dumped into water bodies that are used for drinking and recreational activities. When soil is covered by pavement, it can’t absorb and filter stormwater like it would naturally.

So a group of researchers from Virginia Tech, Cornell University and the University of California at Davis recently released a manual that explains how to use trees in urban stormwater management systems to help protect water resources. The manual, Managing Stormwater for Urban Sustainability Using Trees and Structural Soils, is a novel system that uses structural soils (engineered tree soils) to detain stormwater and allow tree root growth in confined urban areas. The report says this approach more closely resembles the natural water cycle than traditional stormwater management techniques.

“This is a good introduction to the importance of having proper soil into which stormwater can be filtered,” Connolly wrote in an email. “It sounds like Virginia Tech has developed a way to enhance compacted soil so as to allow for perviousness while still supporting pavement and weight on top. If this works, it holds great promise for urban areas.”

This is just one small piece of the puzzle in cleaning up our waterways. The most important thing to understand is that no matter where we live—whether it’s on the coast or miles from a substantial body of water—we live in a watershed. The water that falls on our front porch and on our street and in our neighborhood will hit a body of water eventually.

Now you know what a watershed is. If you want to make a difference and aren’t sure how, start here.

This post was originally published on Smartplanet.com