Stormwater runoff is generated from rain and snowmelt events that flow over land or impervious surfaces, such as paved streets, parking lots, and building rooftops, and does not soak into the ground. This can result in an almost instantaneous significant increase in local stream flows which can cause severe erosion of the stream bed and channel. This can also decrease the flow of streams in the long run because water that should normally seep into the stream over time is quickly flushed away during rain events. The stormwater runoff picks up pollutants like trash, chemicals, oils, and dirt/sediment that can harm our rivers, streams, lakes, and coastal waters. To streams from stormwater pollution, communities, construction companies, industries, and others, use stormwater controls, known as best management practices (BMPs). These BMPs filter out pollutants and/or prevent pollution by controlling it at its source.
The Clean Water Act’s National Pollutant Discharge Elimination System (NPDES) stormwater program regulates some stormwater discharges from three potential sources: municipal separate storm sewer systems (MS4s), construction activities, and industrial activities. Operators of these sources might be required to obtain an NPDES permit before they can discharge stormwater. This permitting mechanism is designed to prevent stormwater runoff from washing harmful pollutants into local surface waters.
- The Alabama Department of Environmental Management is authorized to implement the stormwater NPDES permitting program in Alabama.
Population growth and the development of urban/urbanized areas are major contributors to the amount of pollutants in the runoff as well as the volume and rate of runoff from impervious surfaces. Together, they can cause changes in hydrology and water quality that result in habitat modification and loss, increased flooding, decreased aquatic biological diversity, and increased sedimentation and erosion. The benefits of effective stormwater runoff management can include:
- protection of wetlands and aquatic ecosystems,
- improved quality of receiving waterbodies,
- conservation of water resources,
- protection of public health, and
- flood control.
Traditional stormwater management approaches that rely on peak flow storage have generally not targeted pollutant reduction and can exacerbate problems associated with changes in hydrology and hydraulics.
- Construction Sites : require the use of BMPs at all construction sites to prevent any off site transport of sediment and reduce runnoff. Require submission and approval of Stormwater Management Plans prior to beginning earth disturbing activities. Require post construction water runnoff meet pre-construction hydrology
- Municipalities: require Low Impact Development including stormwater retention BMPs in order to reduce stormwater discharge. Maintain turbidity levels in downstream reaches at natural undeveloped standard
- State: Adequately enforce all stormwater regulations. Develop a robust enforcement program to find violators and bring them quickly into compliance
Alabama Stormwater Partnership, which includes: Cahaba River Society, Mobile Baykeeper, Southern Environmental Law Center, Choctawhatchee Riverkeeper, David Ludder, Friends of Locust Fork and more