2014-00633. Draft Environmental Impact Statement for the Dyke Marsh Restoration and Long-term Management Plan, George Washington Memorial Parkway, Virginia

AGENCY:

National Park Service, Interior.

ACTION:

Notice of availability.

SUMMARY:

The National Park Service (NPS) announces the availability of a Draft Environmental Impact Statement (DEIS) for the Dyke Marsh Restoration and Long-term Management Plan at George Washington Memorial Parkway, Virginia. The DEIS provides a systematic analysis of alternatives for the restoration and long-term management of the tidal freshwater marsh and other associated wetland habitats lost or impacted in Dyke Marsh Preserve on the Potomac River.

DATES:

The NPS will accept comments on the DEIS from the public for 60 days after the date that the Environmental Protection Agency publishes the notice of availability of the DEIS in its regular Friday Federal Register listing. A public meeting will be held during the review period to facilitate the submission of public comment. Once scheduled, the meeting date will be announced via the George Washington Memorial Parkway Web site (http://www.nps.gov/​gwmp/​), the NPS's Planning Environment and Public Comment (PEPC) Web site (http://parkplanning.nps.gov/​gwmp), and a press release to area media.

ADDRESSES:

The DEIS for the Dyke Marsh Restoration and Long-term Management Plan will be available for public review online at the NPS's PEPC Web site (http://parkplanning.nps.gov/​GWMP). You may submit your comments by any one of several methods. The preferred method of commenting is via the Internet at (http://parkplanning.nps.gov/​GWMP). You may also mail comments to Dyke Marsh Restoration Plan, 700 George Washington Memorial Parkway, Turkey Run Park Headquarters, McLean, VA 22101. Or, you may hand-deliver comments to 700 George Washington Memorial Parkway, Turkey Run Park Headquarters, McLean, VA 22101. Written comments will also be accepted at the public meeting. We will not accept comments by fax, email, or in any other way than those specified above. We will not accept bulk comments in any format (hard copy or electronic) submitted on behalf of others. Before including your address, phone number, email address, or other personal identifying information in your comment, you should be aware that your entire comment—including your personal identifying information—may be made publicly available at any time. While you can ask us in your comment to withhold your personal identifying information from public review, we cannot guarantee that we will be able to do so.

FOR FURTHER INFORMATION CONTACT:

Alex Romero, Superintendent, 700 George Washington Memorial Parkway, Turkey Run Park Headquarters, McLean, VA 22101; telephone [phone].

SUPPLEMENTARY INFORMATION:

The purpose of this DEIS is to develop a plan for the restoration and long-term management of the tidal freshwater marsh and other associated wetland habitats lost or impacted in Dyke Marsh Preserve on the Potomac River.

Dyke Marsh Preserve is one of the last large tracts of tidal freshwater marsh along the Potomac River in the Washington, DC, area and has existed for at least 2,200 years.

Located just south of Alexandria, Virginia, Dyke Marsh Preserve is viewed as a national treasure because of its proximity to the Nation's Capital and a large urban/suburban population, its history, and its current potential for providing ecosystem services, recreational values and educational opportunities. Despite continual degradation of the existing marsh, it provides numerous natural benefits and services, including resident and migratory wildlife habitat, refuge for state species of concern, attenuation of tidal energy, shoreline stabilization, flood control, and water quality enhancement.

The goal of the actions described in the DEIS is to restore areas of Dyke Marsh that were previously impacted by dredging and erosion. The park will re-establish soil elevations to sustain marsh plant communities while preventing damage to vegetation in the existing wetland. In the long-term, the project will provide additional wetlands to the Potomac River watershed ecosystems, preserve the aesthetic and natural values of Dyke Marsh and the George Washington Memorial Parkway, and continue to offer recreational opportunities currently available. Specific objectives of the plan are listed below.

Natural Resources. Dyke Marsh Restoration will protect and maintain tidal freshwater wetlands and associated ecosystems to provide habitat for fish, wildlife, and other biota. The park will ensure that management actions promote native species while minimizing invasive nonnative plants. The marsh restoration will reduce or eliminate erosion of the existing marsh and, to the extent practicable, will restore and maintain hydrologic processes needed to sustain the marsh. The restored marsh will protect breeding populations of state species of concern such as least bittern (Ixobrychus exilis), state critically imperiled swamp sparrow (Meloxpiza georgiana ssp. georgiana, G5T5, S1B/S4S5N), and state imperiled species such as river bulrush (Bolboschoenus fluviatilis, G5S2). Finally, the restoration will increase the resiliency of Dyke Marsh, provide a natural buffer to storms, and help ameliorate flooding in populated residential areas.

Cultural Resources. The restoration will protect the historic resources and cultural landscape features associated with Dyke Marsh and the George Washington Memorial Parkway.

Visitor Experience will be enhanced through appropriate educational, interpretation, and research opportunities at Dyke Marsh and enhance access by diverse audiences.

The DEIS analyzes two action alternatives and the no action alternative, as described below.

Alternative A: No Action—Under this alternative, there would be no restoration. Current management of the marsh would continue, which includes providing basic maintenance related to the Haul Road, control of nonnative invasive plant species, ongoing interpretive and environmental education activities, scientific research projects, boundary marking, and enforcement of existing regulations. There would be no manipulation of the marsh other than emergency, safety-related, or limited improvements or maintenance actions. The destabilized marsh would continue to erode at an accelerated rate.

Alternative B: Hydrologic Restoration and Minimal Wetland Restoration—Under alternative B, the focus is on the most essential actions to reestablish hydrologic conditions that shield the marsh from erosive currents and protect the Hog Island Gut channel and channel wall. A breakwater structure would be constructed on the south end of the marsh, in alignment with the northernmost extent of the historic promontory, and wetlands would be restored to strategic areas where the water is less than 4 feet deep. This alternative also includes fill of some deep channel areas near the breakwater. The final element of this alternative is the reestablishment of hydrologic connections to the inland side of the Haul Road to restore bottomland swamp forest areas that were cut off when the Haul Road was constructed. Approximately 30 acres west of the Haul Road could be influenced by tidal flows as a result. These actions would not necessarily happen in any particular order, and may be dictated by available funds. However, it is assumed that the breakwater would be constructed first. This alternative would create approximately 70 acres of various new wetland habitats and allow the continued natural accretion of soils and establishment of wetlands given the new hydrologic conditions.

Alternative C: Hydrologic Restoration and Fullest Possible Extent of Wetland Restoration (NPS Preferred Alternative)—Under alternative C, the marsh would be restored in a phased approach up to the historic boundary of the marsh and other adjacent areas within NPS jurisdictional boundaries. Phased restoration would continue until a sustainable marsh is achieved and the overall goals of the project are met. The historic boundaries lie between the historic promontory and Dyke Island, the triangular island off the end of the Haul Road. The outer edges of the containment cell structures would be placed at the park boundary in the river.

The initial phase of this alternative would first establish a breakwater structure at the southern alignment of the historic promontory to provide immediate protection to Dyke Marsh from erosion. After the breakwater is established, the deep channel areas north of the historic promontory would be filled within the NPS boundary, and the marsh would be restored to the 4-foot contour at strategic locations to further reduce the risk of erosion and storm surges and promote sedimentation within the existing marsh. Afterwards, two cells would be constructed along the northern edge of the breakwater, restoring the original extent of the promontory's land mass.

All subsequent phases would establish containment cells out no further than the historic marsh boundary. The location of these cells would be prioritized based on the most benefits the specific locations could provide to the existing marsh. The timing of these subsequent phases and the size and number of cells built during these phases would be dependent upon available funds and materials.

In addition to the construction of containment cells, tidal guts would be cut into the restored marsh area that would be similar to the historical flow channels of the original marsh.

This alternative, like Alternative B, would also introduce breaks in the Haul Road, returning tidal flows to approximately 30 acres west of the Haul Road, which would help to re-establish the historic swamp forest originally found on the site.

Additional wetland may be restored south of the new breakwater to fill out the southernmost historic extent of the marsh. This area would not be protected from storms, and would be one of the last features implemented. In addition, the marsh restoration would extend north of Dyke Island, and tidal guts would be created. This alternative contains an optional restoration cell in the area currently serving as a mooring area for the marina. Such an option would only be implemented should the marina concession no longer be economically viable for the current concessioner, and then only if no other concessioner expresses interest in taking over the business, which would eliminate the need for the mooring field. In total, under this alternative, approximately 245 acres of various wetland habitats could be created.

Dated: October 21, 2013.

Stephen E. Whitesell,

Regional Director, National Park Service, National Capital Region.