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Beaver Marsh Trail - #8 - Urban Runoff


What is stormwater runoff?

Storm water runoff is water that flows on the land that comes from rain or melted snow into the ground or into a body of water.

What is polluted runoff?

Picture of Polluted Runoff

Polluted Runoff

Storm water runoff is water that flows on the land that comes from rain or melted snow into the ground or into a body of water. The most basic principle to remember about stormwater is that no matter what, “water runs downhill”. When this runoff flows over the land surface, it can pick up and carry any chemicals, sediment, garbage, etc. and, as a result, become polluted. This can be extremely harmful when this water picks up chemicals like fertilizer, pesticides, oil, or sediment. Even items like grass clippings and leaves can be harmful if they accumulate enough in runoff. Although runoff is unavoidable and part of the natural Hydrologic Cycle, it is made much worse by human activity and can ruin entire ecosystems.

What causes polluted stormwater runoff?

The most common reason for polluted runoff is land modification such as adding of pavement and roads which prevent water from seeping into the ground immediately. This means that water will flow through the streets and more likely pick up pollutants. Human activities such as using fertilizers or pesticides on your lawn or allowing your dog to poop outside without cleaning it up causes polluted runoff.

Why do we need to manage stormwater and polluted runoff?

Picture of stormwater drainage

Stormwater Drainage

Polluted stormwater is the biggest cause of water pollution in North Carolina. Because we, for the most part, do not treat storm water runoff, it is allowed to flow freely and contaminate bodies of water like streams and lakes and reservoirs. This can impact human health and make living more expensive. It takes much more money for local communities to clean contaminated water sources. It also can negatively impact aquatic species, such as fish, mussels, and insects that depend on clean water for survival.

How is stormwater “managed”?

Picture of stormwater reservoir

Stormwater Reservoir

Have you ever heard the expression “An ounce of prevention is worth a pound of cure”? Although it may be counterintuitive, preventing pollution is much easier than cleaning it. Simply educating the public about ways to avoid pollution such as avoiding littering or leaving pet waste can help significantly. One other way is to provide incentives for local construction companies to implement systems that reduce erosion and encourage recycling and proper waste disposal/clean up. Stormwater best management practices (BMPs) and green infrastructure (GI) are effective ways to reduce negative consequences of runoff from construction and urban/suburban development. These practices reduce stormwater runoff and slow runoff down, allowing for the ground to better absorb the stormwater and filter pollutants before it reaches a stream.

More Info

For more information on stormwater BMPs and Green Infrastructure, check out these links:



Ellerbe Creek Watershed Association
331 W. Main, Ste. 511
Durham, NC 27701

These web pages are the Eagle Scout project of Mathew Jacob.
Thanks Mathew!