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The Baltimore District and the National Park Service (NPS), George Washington Memorial Parkway, are working on a project to restore up to 100 acres of freshwater tidal marsh within the 485-acre Dyke Marsh Wildlife Preserve in Fairfax County, Virginia, which is just across the Potomac River from the National Harbor.
Dyke Marsh is one of the best studied wetlands in the U.S. and is the largest remaining freshwater, tidal wetlands in the Washington metropolitan area. It is home to more than 300 species of plants and 270 species of birds – including the previous home to the only breeding population of marsh wrens in the region. It has extensive value - not only for the wildlife - but for the recreational, educational and cultural values that the marsh provides.
However, the marsh has been altered due to 40 years of mining and other human factors. In addition, the marsh is eroding an average of 6 to 7.8 feet per year due to storm waves from large weather events.
These factors have left the area exposed to storm waves, susceptible to erosion, and unable to sustain itself.
A 2009 investigation of Dyke Marsh by NPS and the U.S. Geological Society found that this unique ecosystem would be entirely lost by 2035 without restoration efforts.
In 2013, Congress recognized Dyke Marsh as an invaluable resource to the District of Columbia region and allocated $24.9 million to restore the site.
This vital interagency project will provide a storm buffer for the historic and scenic George Washington Memorial Parkway, a natural filter to clean the Potomac River, and critical habitat for a variety of wildlife.
The wetlands at Dyke Marsh will be restored using clean sandy material and planted with native wetland vegetation. The peninsula to the south of the marsh that had been previously removed will also be restored.
The restoration efforts are anticipated to begin summer 2017. The team is currently designing the project and conducting investigations. Construction is anticipated to be completed in 2019. NPS will continue to monitor of the site to ensure no invasive species become established and that restoration efforts are on track, as it takes time for habitat to develop and self sustain.