Across the nation, attention has shifted to distributed or “nonpoint” sources of pollution such as stormwater runoff. According to an inventory conducted by the United States Environmental Protection Agency (EPA), half of the impaired waterways are affected by urban, suburban, and construction sources of stormwater runoff. Stormwater presents new challenges in water management and minimizing pollution.
Stormwater runoff normally is not treated by sewage and wastewater treatment plants. More often than not, end-of-pipe controls are not the best answer for removing pollutants from stormwater runoff. The best means of control is usually at the pollutant's source. Proper storage of chemicals, good housekeeping and just plain paying attention to what's happening during runoff events can lead to relatively inexpensive ways of preventing pollutants from getting into the runoff and then being transported to our groundwater, wetlands, and waterways.
Stormwater management practices are used to delay, collect, store, treat, or infiltrate stormwater runoff. While specific design objectives for stormwater management practices are often unique to each watershed, the general goals for stormwater management practices usually include the following:
- Maintain groundwater recharge and quality
- Reduce stormwater pollutant loads
- Protect stream channels from erosion
- Prevent increased overbank flooding
- Safely slow the velocity and carrying capacity of stormwater