What is Stormwater Management?
When it rains or snows, the amount of water that is absorbed back into the environment varies largely on whether the land is paved or natural. Rain and snow on natural or undeveloped land gradually infiltrates into the soil, replenishing groundwater supplies and slowly discharging excess runoff to local creeks. In contrast, as we pave roads and sidewalks, construct buildings or add other impervious surfaces, the amount of water that can be naturally absorbed after a rain or snow event is reduced drastically. Water that cannot infiltrate into the surrounding environment is called water runoff or stormwater runoff. In order to prevent our communities from flooding, stormwater runoff is diverted into the storm drainage system and carried to the nearest stream. Ultimately, this runoff makes its way to the Chesapeake Bay through our numerous watersheds.
Because impervious surfaces prevent stormwater from infiltrating into the soil, runoff increases in quantity and speed, causing environmentally harmful, and potentially dangerous, bank erosion in streams. As stormwater runoff flows over pavement and yard areas, it picks up pollutants like nutrients, oils, sediment, trash, heavy metals and chemicals that are left on our streets and walkways. Eventually, all those pollutants make their way down through our watersheds to the Potomac River and the Chesapeake Bay.
In order to help prevent bank erosion and pollution in our watersheds, engineers and biologists have worked together to develop “Best Management Practices,” also called BMPs, to accommodate stormwater runoff while minimizing environmental impacts. Best Management Practices encompass a wide range of man-made structures, such as stormwater management facilities, or simple everyday preventative house-keeping measures, such as picking up after pets and not littering.
Stormwater management facilities are developed to reduce the amount or quantity of stormwater runoff and provide time for most pollutants to settle in a holding area where they will not be transported to streams. Typical stormwater management facilities used in residential and commercial areas include: dry and wet ponds, rain gardens, trenches, pervious pavement, wetlands and manufactured facilities (which are usually underground baffling systems designed to filter out certain pollutants).
For additional information, or to request this information in an alternate format, please email the Maintenance and Stormwater Management Division or call 703-877-2800, TTY 711.
maintenance and inspection:
Email the Maintenance and Stormwater Management Division or call 703-877-2800, TTY 711
Stormwater/watershed planning and project implementation:
Email the Stormwater Planning Division or call 703-324-5500, TTY 711
New facilities under construction:
Email the Environmental & Facilities Inspection Division or call 703-324-1950, TTY 711
Additional assistance with private stormwater
Email the Northern Virginia Soil & Water Conservation District or call 703-324-1460, TTY 711