Fairfax County, Virginia
Owner: Fairfax County Park Authority
Huntley Meadows Park was established in 1975 and encompasses approximately 1,500 acres. The central wetland area is the largest non-tidal wetland in Northern Virginia and resulted from beaver-damming activity in the late 1970s. The wetland transitioned into a hemi-marsh, as system that has one of the highest levels of biodiversity and ecological function. Unfortunately, over time the wetland deteriorated due to a uniform, unmanageable water level; siltation from upstream development north of the park; the herbivorous feeding habits of Canada geese; and natural succession. Prior to restoration, the wetland area was dominated by large, monotypic stands of invasive species as a result of uniform shallow water levels, which greatly reduced the diversity of wildlife habitat and degraded the ecological function.
After two attempts by others, the Fairfax County Park Authority (FCPA) contracted Wetland Studies and Solutions, Inc. (WSSI) in 2011 to restore the central wetland area as a hemi-marsh system. In order to create and maintain this condition, WSSI faced the significant engineering challenge of raising the permanent water surface elevation with the ability to accurately control the water level. Control structures were engineered to provide this necessary flexibility – these included a ±450 ft earthen berm with a vinyl sheet-pile core (to prevent short-circuiting through the dam) that was designed to be overtopped in larger storm events, along with a concrete riser equipped with adjustable slide gates that provide maximum flexibility in controlling the elevation of the normal pool of the impoundment.
WSSI, in collaboration with the FCPA, has successfully re-created a hemi-marsh system. The Park receives approximately 200,000 visitors a year and conducts over 400 programs with 10,000 students every year, and the project has not only met all budget and time constraints, but also won the approval of FCPA staff and skeptical citizen activist groups with close ties to the Park.
One of the primary successes of this project is the degree to which traditional, “hard” engineering practices were employed to meet the goals of a project that were strictly environmentally based. In addition, these practices can be successfully employed in extremely sensitive environments. Huntley Meadows Park is a highly prized and fiercely protected natural resource in a highly urbanized area. There is a long history of citizen activism and public engagement with the project to protect it from harm and to ensure restoration of the main wetland.