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Historically, the Anacostia estuary was a fully functional freshwater tidal marsh comprising several thousand acres that provided considerable food and habitat for wildlife and consequently served as an invaluable support resource for native Indians and subsequent colonists. Towards the end of the nineteenth century as sewage pollution, agriculturally derived sediments, surrounding development and disease threats increased in the Anacostia, intense pressure developed to remove the problematic wetlands. The U.S. Army Corps of Engineers (COE) was given the charge to dredge the Anacostia from its mouth at the Potomac in Washington, D.C. up to Bladensburg, Maryland. In addition to dredging, a stone seawall was built which yielded a hard line between the dredged river channel and the deposited fill behind the seawall. Essentially no emergent wetlands remained including areas within the dredged out tidal Kenilworth and Kingman Lakes. The National Park Service (NPS) eventually became the custodian of these newly built landscapes which were to be used mostly for recreation. In the 1980s park planners and resource managers began to envision the opportunity of restoring areas like Kenilworth Lake as a vestige of the once productive wetland habitat. Following a long series of planning and technical evaluations Kenilworth Marsh was reconstructed by the COE for the NPS as a freshwater tidal marsh (32 acres) in the highly urbanized Anacostia watershed in 1993. A similar reconstruction of tidal wetlands at the Kingman Lake site began during the spring of 2000 also using pumped dredge material from the Anacostia channel. Monitoring of various aspects of the restored wetlands at the Kingman site was conducted over a 5-year period (2000-2004). We focused upon the vegetation and soil characteristics of the site. These are important characteristics that affect the value of the site as habitat for fish and wildlife, the biogeochemical and hydrologic functioning, and the aesthetic value. Vegetation monitoring included two components: standing vegetation and seed bank which involved buried viable seeds as well as water and air born sources. Monitoring of soils involved measurements of soil particle size, organic matter, and redox potential (Eh). The vegetation, soil structure and seed bank were the units of measure and were thus used for comparison to the reference wetlands. Additional studies pertaining to site hydrologic function, sediment processes, benthic macro-invertebrates, and avian populations were also pursued.
The project measured the progress of the reconstructed marsh toward becoming a natural, viable freshwater tidal wetland. As such the project served as a learning curve and example for future restorations along the Anacostia and elsewhere. Consequently, the project will provide the COE as builders of the reconstructed wetland, the National park Service (NPS) as managers of the wetland, and the District of Columbia as the jurisdiction in which the wetland resides, an evaluation of the reconstructed marsh processes and the product wetland. By monitoring the vegetation, seed bank and soils, a verifiable documentation of the quality of the wetland as it matured over the five year monitoring period were made. The project helped identify and characterize situations that required actions to correct the defects during the formative stages of the wetland (adaptive management actions). It was hypothesized that documentation of the avi-fauna use over time would also help describe the rate and degree of maturation processes at the urban reconstructed freshwater tidal wetlands. Having two similar nearby (one half mile apart) urban reconstructed wetlands (Kingman 2000 and Kenilworth 1993) seven years apart in age provides an excellent opportunity to study the marsh restoration processes relative to each other over time as well as to nearby reference wetlands.
Any questions or correspondence regarding this work may be sent to Richard Hammerschlag, Phone 301-497-5555 Fax. 301-497- 5624
These Annual Reports and the Final Reports document the monitoring and research conducted by the USGS Patuxent Wildlife Research Center and the University of Maryland Department of Biological Resources Engineering team for the five-year project (2000-2004) sustained by funding from the Baltimore District of the Army Corps of Engineers, the District of Columbia Department of Environmental Health, the USGS Patuxent Wildlife Research Center and the University of Maryland.
Please cite the report(s) as follows:
Hammerschlag, R. S., A. H. Baldwin, C. C. Krafft, M. M. Paul, K. D. Brittingham et al. The Year of the particular Report. The Report Title. USGS Patuxent Wildlife Research Center, Laurel, Maryland.
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