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Historically, much of the original land in the District was a wetland that supported a rich biodiversity of plants and wildlife. Water formed natural boundaries on three sides of the original city including: the Potomac River on the south, Rock Creek to the west, and the Anacostia River on the east. L’Enfant’s plan for the District centered on three high and dry knolls that overlooked the Potomac estuary and wetlands:
- Jenkins Hill on the Wicomico Terrace became Capitol Hill,
- the Burnes Farm knoll on the Talbot Terrace became the site for the White House, and
- Easby’s Point was used as a defense site and the site of the old Naval Observatory at 21st and C Streets NW (O’Connor 1985).
A stream called Tiber Creek once flowed between the White House and the Capitol, where Constitution Avenue runs today. In the 1870’s the B&O railroad opened a commuter line that covered Tiber Creek between Union Station and Catholic University. Tiber Creek emptied into the Potomac River through a wetland that later became the site of the Washington Monument. Additional urban development covered the remaining portion of Tiber Creek and its tributaries that now flow in storm drain pipes (Williams 1997).
The Anacostia River and its estuary separate the eastern segment of the District from the rest of the District. Until the 1880’s, the Anacostia River was twice its width and supported hundreds of acres of wild rice and submerged aquatic vegetation. Development filled these wetlands for the construction of highways, power plants, military bases, and industrial parks.
From the 1800’s to the mid 1900’s, wetlands in the District were significantly reduced and impacted by:
- colonial agriculture practices,
- use as dumpsites,
- filling,
- draining,
- dredging, and
- land reclamation.
Land reclamation in the 1800’s involved dredging the Potomac and Anacostia Rivers and placing the dredged material in tidal flats and adjacent wetlands. Wetlands were also filled in the 1800’s, or reclaimed, to eliminate breeding grounds for the anopheles mosquitoes, which carry the malaria parasite.
A large percentage of the historical wetlands in the District have been drained, filled, or impacted as urbanization occurred over the past two hundred years. Seawall construction along the Anacostia resulted in the loss of approximately 90 percent of the tidal marshes in the early 1900’s (Bernstein and Shepp 1992). Although DC is almost fully urbanized, our remaining wetlands continue to be impacted by:
- runoff from impervious surfaces like concrete and asphalt,
- industrial and municipal wastewater discharge,
- urbanization,
- fragmentation,
- invasive species,
- point source pollutant discharges (e.g. combined sewer overflows),
- non-point source pollution (e.g. runoff),
- increased sedimentation, and
- filling of wetlands.
The Wetland Mapping Project will provide DOEE, land planners, environmental groups, and concerned citizens with an updated Wetland Conservation Plan and better tools to work toward the goal of no net loss of wetlands and eventual gain of wetland acreage in the District.
References
Bernstein, B. and D. Shepp. 1992. Restoring Tidal Wetlands in the Anacostia. In: Watershed Restoration Book. Department of Environmental Programs, Metropolitan Washington Council of Governments. Washington, DC. pp. 125-144.
O’Connor, J.V. 1985. The District of Columbia: The Men Who Most Influenced the Development of the Capital of the U.S. Used Geologic Features to Shape the City. Earth Science, Fall 1985. Pp. 11-15.
Williams, G.P. 1997. Washington D.C.’s Vanishing Springs and Waterways. U.S. Geological Survey Circular 752. 19 pages.