Restoring an Urban Watershed
The Anacostia River watershed is listed as one of the most impaired rivers in North America by American Rivers, Inc., an Areas of Concern by the Chesapeake Bay Program, and focus area for the U.S. Fish and Wildlife Service's Chesapeake Bay Field Office. The Anacostia is also a pilot program for the Urban Waters Federal partnership a collaborative initiative to revitalize polluted urban waterways to improve natural resources, the quality of life of surrounding communities and the local economy.
The job of restoring the Anacostia River and its tributaries is a daunting task. Activities like removing trash or patching eroding banks may help treat some of the symptoms. But a more holistic approach is needed for the Anacostia to support thriving communities of fish and other wildlife. The U.S. Fish and Wildlife Service, Chesapeake Bay Field Office (Service) and the District of Columbia, Department of the Environment (DDOE) formed a partnership to take on this challenge.
Looking at the Big Picture
The first step was to conduct a watershed -wide assessment of the cause and effect relationship between land activities and stream processes. Physical features of streams, such as channel dimension, pattern and profile, are characterized and the stability conditions assessed. Watershed characteristics such as land use, land cover, soil types, hydrology, topography and geology are also documented. Using historical maps and aerial photography, one can also develop an understanding of how a stream responds to certain land changes over time.
Restoration activities are then prioritized based on the severity, complexity, and scale of stream problems and the potential for the stream to recover on its own. Other factors such as concerns of local land owners, and improvements for wildlife also play a role.
The Watts Branch assessment showed conditions typical of an urban environment. Conversion of tributaries to piped or concrete-lined storm drains have altered the hydrology, making these tributaries unstable with high stream velocities causing sediment loading from bed and bank erosion. The Service estimated that 1,500 tons of sediment erodes from the stream banks of Watts Branch each year.
Because of its severely degraded conditions, Watts Branch was rated as a high restoration priority. To improve instream and streamside (riparian habitat), the Service would use natural channel design methods to restore Watts Branch to a stable, self-sustaining waterway.
Watts Branch currently lacks riffles and pools for aquatic wildlife, and has significant bank erosion occurring throughout the proposed 1.8-mile restoration area. The design incorporated instream structures to improve riffle and pool habitat and to reduce bank erosion. Floodplain creation will store flood water and improve stability by reducing stress on stream banks. Soil lifts, matting, and the planting of native grasses, shrubs, and trees will also stabilize the stream banks thereby reducing erosion.
To further improve water quality and reduce storm water runoff, DDOE is using Best Management Practices throughout the watershed. Additionally, the Washington Water and Sewer Authority is rehabilitating, replacing, or relocating the sewer lines impacting Watts Branch.
Benefits to Wildlife
The Anacostia watershed historically provided important spawning and nursery habitat for fish like American eel, alewife, American shad, Atlantic sturgeon and striped bass. The reduction in bank erosion on Watts Branch will improve water quality and benefit aquatic species downstream of the restoration area, in the Anacostia River and ultimately the Chesapeake Bay.
Other wildlife that will benefit from the restoration of streamside forest and floodplain habitats include: the Acadian flycatcher, willow flycatcher, prothonotary warbler, wood thrush, red-eyed vireo, northern parula, and yellow warbler. Cooper's hawk, red-shouldered hawk, and barred owl are also found in the area. Great blue heron and green heron populate the wetland areas.
Partners for the $2.7 million restoration project included the U.S. Fish and Wildlife Service – Chesapeake Bay Field Office, District of Columbia Department of the Environment, Natural Resource Conservation Service, Environmental Protection Agency, National Fish and Wildlife Foundation, National Park Service, Washington Water and Sewer Authority and Washington D.C. Parks and Recreation.
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