Wetlands are among the most productive ecosystems in the world and vital to the ecology of healthy watersheds. They provide a wealth of benefits to humans, water quality, and wildlife through functions including storage of floodwater; shoreline erosion protection; recharge of groundwater that sustains river and stream baseflow; and, retention, assimilation, or transformation of nutrients and pollutants that can degrade downstream water quality. In addition, wetlands are integral components of food webs, providing nursery habitat for breeding fish, amphibians and birds, habitat for wildlife, and export of organisms to downstream waters. Wetlands also act as buffers to protect downstream waters from pollution.
Within the District, 296 acres of wetlands have been mapped and assessed in the field. Over 92% of the District’s potential wetlands (areas determined to have wetland characteristics via a desktop analysis) are located within 500 feet or less of urban development. These urban wetlands face constant challenges such as habitat loss from development, fragmentation, and altered hydrology as well as degraded water quality from stormwater runoff, scour from heavy rain events, and invasive plant colonization. Conservation of these important natural resources is vital to the ecology and health of the District’s residents, watersheds, wildlife, and economy.
Streams, including ephemeral streams that do not have water year round, mitigate damage from floods, and provide habitat and food for aquatic species, semi-aquatic species, waterfowl, and other wildlife. Headwater steams are a source of water, nitrogen, organic carbon, and sediment to downstream waters. Despite their small individual size and distance from downstream waters, headwater streams, including ephemeral streams, cumulatively supply most of the water in rivers. Downstream waters are the time-integrated result of all waters contributing to them.
Once a major feature of the landscape, wetlands within the District are now scattered in fragmented patches along the banks of the Anacostia River, Potomac River, and within isolated stream valleys. For more read the history of wetlands in the District.
Wetland and Stream Regulations
On May 14, 2021 DOEE adopted a final rulemaking to add new Chapters 25 (Critical Area – General Rules) and 26 (Critical Area – Wetlands and Streams) to Title 21 of the District of Columbia Municipal Regulations (DCMR). These final rules became effective on the date of publication in the D.C. Register.