A canoe ride or hike around Lake Accotink in Springfield is a summertime staple for many Fairfax County residents. The 55-acre lake and the 493-acre wooded park surrounding it offer ample opportunities for recreation and wildlife viewing, an ideal location to spend a warm, lazy afternoon or to get away to after a tedious day at the office.
However, as serene and idyllic as everything may appear on the surface, trouble lurks beneath those translucent waters.
According to the Fairfax County Park Authority, which oversees the park, Lake Accotink is in danger of disappearing due to the sediment that has steadily accumulated over the past several decades.
“Sedimentation has been a constant problem for Lake Accotink,” said Gayle Hooper, a landscape architect in the Park Authority’s park planning division.
Hooper has been appointed project manager for the department’s ongoing Lake Accotink Park master plan revision, which launched with a public meeting on Mar. 14 at Cardinal Forest Elementary School in Springfield.
The park master plan was first developed in 1964 and undergoes revisions whenever the park or its surrounding community experiences significant changes. The plan was last updated in 1993.
The Park Authority designs its master plans to achieve a balance between the facilities its parks offer to serve the community and the conservation of natural and cultural resources.
Though there are other elements to the master plan, sedimentation is the biggest challenge facing Lake Accotink Park right now.
Hooper describes sedimentation as a natural process where, in the case of Lake Accotink, stormwater runoff picks up soil, rocks and other particles and carries them downstream until those particles eventually settle at the bottom of the lake.
The explosion in development throughout Fairfax County has resulted in more impervious surfaces, such as roads or concrete pavement, that increase the amount of runoff that enters the streams in the Accotink Creek watershed, which encompasses 51 square miles with 30 square miles that drain into Lake Accotink. The increased mass and speed of those streams leads to more erosion of the stream banks, adding to the amount of sediment in the water.
When the U.S. government first built the dam to create a lake in 1940, Lake Accotink was 23 feet deep. It is now a mere four feet deep.
The Park Authority previously addressed the issue of sedimentation by conducting dredging operations, where workers physically pulled up sediment from the bottom of the lake to restore its depth.
The first dredging operation occurred in 1984, and there was another one in 2004, but these operations are expensive, time-consuming and labor-intensive, requiring trucks to haul the recovered sediment to storage facilities and necessitating park shutdowns that could last up to two years.
Because they can only gather so much sediment, dredging operations must also be repeated approximately every 15 years.
To address this problem, the Fairfax County Board of Supervisors approved project funding for the Lake Accotink Park master plan revision in 2014, and the county hired consulting firm Wetland Studies and Solutions (WSSI) to develop possible courses of action.
WSSI director of engineering Frank Graziano presented a list of technically feasible alternatives to county residents during a workshop meeting held Monday at Kings Glen Elementary School in Springfield.
In addition to undergoing another dredge operation that would restore the lake’s depth up to eight feet, the suggested options include creating a sediment forebay that would collect incoming sediment at the basin where streams enter Lake Accotink or constructing in-line “beaver dams” along the main river to reduce the amount of sediment that reaches the lake.
Both those options would also require dredging, but the forebay would extend the time between operations to 30 or 40 years.
WSSI also proposed demolishing the existing dam to eliminate Lake Accotink altogether and turn the park into more of a hiking or wildlife viewing destination with a river. The final suggestion was to modify the dam so that there would be a smaller lake with a single channel running alongside it.
Because the study is still in its early stages, WSSI and the Park Authority haven’t yet conducted any in-depth research of the costs or potential environmental impacts of the proposed projects.
The Environmental Protection Agency (EPA) is also scheduled to release new Total Daily Maximum Loads (TMDL), which set regulations for pollution as required by the Clean Water Act, at the end of the year.
Those new standards could affect the viability of alternatives for Lake Accotink, particularly those that involve altering the dam.
“I really couldn’t say what the best option is,” Park Authority project branch manager John Lehman said. “Some of the options would eliminate the lake. That would make it unacceptable to a lot of people, so there are pluses and minuses with each option.”
Lehman, who was previously also involved with the 2004 dredging operation, says that the Park Authority wanted to get community input on the master plan before the TMDLs came out because the process takes a long time.
The department’s main goal is to develop a plan that’s sustainable, meaning it takes environmental, social or community-oriented, and financial considerations all into account.
Many attendees at the workshop meeting shared stories about their experiences at Lake Accotink Park as they discussed the Park Authority’s presentation.
For example, David Kepley, a community council member of the nonprofit Faith Alliance for Climate Solutions, has lived in Fairfax County with his family for 35 years and regularly visits the Lake Accotink Park to hike, ride his bike and watch wildlife, including the bald eagles that have nested in the trees beside the lake.
He currently lives in near Long Branch Valley Stream Park and says there’s a restoration project taking place on a stream behind his house that eventually feeds into Lake Accotink. Watching that stream erode the dirt bank prompted him to attend the workshop meeting so that he could understand the big picture.
“I’m mostly concerned about the environmental standpoint,” Kepley said. “[However], it’s a lake in the middle of a community, so the people have to be considered, because it’s their tax dollars that are going to fund all of these projects anyway.”
All of the residents at the meeting expressed a strong desire to keep the lake, though many people noted that it’s difficult to make any decision without more details about possible impacts on park wildlife or project funding. Some also wondered whether some of the options could be combined.
Kings Park resident Bobby Bancroft has visited Lake Accotink Park since he was a kid and finds the park valuable because it lets him spend time in nature without having to drive or venture too far from home.
“You have to do things within reason,” Bancroft said. “I’d like to keep the lake, but if it doesn’t make sense for the sediment or cost-wise, then you have to figure out what makes the most sense.”
http://www.fairfaxtimes.com/articles/fairfax_county/lake-accotink-in-danger-of-becoming-no-more/article_0c397da4-1ece-11e6-9ec1-431c56f74e00.html