To the Editor:
This week, the National Park Service (NPS) held a public meeting to discuss four optional courses of action concerning the erosion of Dyke Marsh. The Marsh is a tidal marsh where the brackish waters of the Potomac River ebb and flow with the tide, covering land at high tide and exposing land at low tide. While Dyke Marsh is a relatively large example of a tidal marsh, numerous other examples abound in the Potomac River and its tributaries. The main distinction is that Dyke Marsh is located within a national park, the George Washington National Historic Parkway Park. This introduces the prospect of using federal funding to restore it.
Comparing Dyke Marsh in 1937 with its status now, the marsh has lost 270 acres to the Potomac River, mainly through dredging operations that occurred from 1940 to 1972. The dredged materials were used for purposes including filling the river to create Reagan National Airport, Columbia Island and the land underlying the Pentagon. Since the marsh is an important natural resource that currently encompasses 60 acres and is eroding at a rate of 1-2 acres per year, action must be taken to stop ongoing erosion. The question is, should portions of the dredged and eroded marsh be restored, and to what degree?
In my Sept. 16, 2010 letter to the Gazette, I pointed out that restoring the 270 acres to the marsh would require over 1.3 million cubic yards of fill, a line of dump trucks extending from Mount Vernon to Chicago. Of the four options discussed at the meeting, one is to do nothing and the other three propose restoring 30, 140 or 180 acres, respectively. Of course, doing nothing is unacceptable, but the 180 acre option is equally so, because the result would be elimination of Belle Haven Marina, a well-used recreational resource that is strongly supported by boating constituencies as well as our Congressional delegation.
Of the remaining options, restoring 30 or 140 acres, which is more appropriate? One current feature adjacent the remaining marshland is a lengthy 12-20 foot deep furrow created by the dredging that provides a year-round habitat for a variety of fish. While that feature didn't exist in 1937, it is there now. The 140-acre option includes filling in that furrow. Eliminating an important fish habitat would be unconscionable. I presume the Friends of Dyke Marsh (FODM) would oppose destroying a furrow that provides a home for a significant fish population. After all, FODM opposes an Off-Leash Dog Area (OLDA) at Westgrove Park, alleging, among other things, an adverse impact on indigenous wildlife. While FODM's animal habitat arguments concerning the OLDA aren't credible, wouldn't it be hypocritical for FODM to support destruction of an animal habitat at Dyke Marsh? Moreover, at the public meeting, Bill Springer of the project's hydrology consultant R K & K Engineers reported that filling in the furrow provides no benefit to Dyke Marsh.
In my view, the 140-acre option goes too far. Proponents of Dyke Marsh restoration should support the 30-acre option because it is feasible, potentially fundable and would be a good start, perhaps paving the way for further restoration. Titled "Alternative Concept B," the 30-acre option includes construction of a promontory wall to the south that would extend offshore a significant distance with a top edge about 3-4 feet above sea level. The purpose for the wall would be to dissipate the energy of storm surges from the south, such as occurred during Hurricane Isabel. Mr. Springer indicated that storm surges from the south are the greatest source of erosion of Dyke Marsh. I would suggest augmenting Alternative Concept B by filling several acres north of the wall, as partially proposed in the 140-acre option (Alternative Option C), to enhance storm surge dissipation.
This would be a good starting point.
NPS is receiving comments concerning possible restoration of Dyke Marsh until June 20. They can be submitted on-line through the project website at http://parkplanning.nps.gov/gwmp. Interested parties should share their thoughts.
H. Jay Spiegel
Mount Vernon