Lake Accotink Dam Fish Kill

Lake Acotink DamThis starts with an email from a park visitor.

On a recent Saturday evening, a park patron sent us a note telling us that she and other visitors were concerned about dead fish they saw below the dam at Lake Accotink. It appeared that the fish had been trapped after water receded and left them stranded behind rocks.

The patron’s email expressed concern over the oxygen level in the pool, the health of the fish, and the possibility of dying fish attracting other wildlife to the spot, which is near a paved hiking trail.

At first glance, it sounded like a naturally occurring event, the whims of nature. But that wasn’t the issue, and the visitor’s email proved to be quite valuable. It brought forward a problem apparently caused by another visitor to the park.

Usually, water flows out of the basin below the dam and runs through a culvert under the paved hiking trail. But that wasn’t happening.

Lake Accotink Park Manager Julie Tahan explained: “Someone had placed rocks in the sluiceway last week, blocking it enough to prevent water from flowing through the sluiceway. The blockage caused the water level in the stilling basin to rise, which created an inviting pool on the upstream side of the triple culvert under the trail. Fish congregated there, which is what we think may have been the motivation for whomever blocked the sluiceway.”

In a rainstorm the improperly moved rocks will cause the water below the dam to flow over the trail, which hampers trail use and is at least an inconvenience if not an endangerment to hikers and bikers. In addition, moving the rocks is a violation of park regulations, and the trapping of fish in this manner is a breach of outdoor sportsman ethics.

Staff had to spend time removing the rocks, which brought the stilling basin back to its normal level but also caused the pool of water harboring fish to recede. The fish were trapped in turbid water and likely succumbed to low oxygen. Tahan says an attempt to save the fish would have had limited success because of the labor involved, the small size of the fish, and the difficulty of netting them in the rocky, murky pool.

This has happened in previous years, and Tahan says that it’s happening again more frequently. She added, “On Saturday – the day after staff removed all the rocks — a patron reported seeing a man placing rocks at the dam. He was gone when we went to check it out.”

Staff from the Virginia Department of Environmental Quality (VDEQ) corroborated what the Park Authority found and said there is not much that can be done to prevent it. VDEQ ruled out chemical or hazardous spills as a cause of the fish kill, agreeing that the fish died from lack of oxygen.

“Knowing that Accotink Creek is in a highly impaired watershed, any aquatic life that does live in its waters is already challenged to survive,” Tahan said. “Additional stress on their habitat can easily have a detrimental impact.”

By Monday, fish that survived had made their way into the deeper waters of the creek that drains the lake, and the eagles, herons, and other birds that include fish in their diets were removing those that did not survive.

Tahan noted that this can be visually unappealing to human sensibilities, however the Park Authority does not try to control every aspect of nature, especially a temporary one like this. Any birds or snakes feeding in the area already are common in the park and are being good stewards of nature.

The Park Authority is considering steps to solve the rock-moving problem. Patrolling the area eats into valuable staff time, and posting cameras as monitors has been suggested but has costs. One other possibility is to ban fishing at the stilling basin. Tahan says that allowing folks to fish there may tempt them to move the rocks, and a ban on fishing at the spot would alleviate a longstanding situation of fishermen setting up in the path of bikers and walkers using the trail. There would still be plenty of fishing opportunity along the creek and in the lake itself.

Notifying the Park Authority of the trapped fish was the right thing for the park visitor to do and is something we encourage when a visitor sees something they feel is amiss in a park. It shows care and concern for nature, for parks and for a healthy environment. At Lake Accotink, the number to call to notify staff of improper activity is 703-569-3464.




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About Fairfax County Park Authority

About Fairfax County Park Authority HISTORY: On December 6, 1950, the Fairfax County Board of Supervisors created the Fairfax County Park Authority. The Park Authority was authorized to make decisions concerning land acquisition, park development and operations in Fairfax County, Virginia. To date, 13 park bond referenda have been approved between 1959 and 2016. Today, the Park Authority has 427 parks on more than 23,000 acres of land. We offer 325 miles of trails, our most popular amenity. FACILITIES: The Park system is the primary public mechanism in Fairfax County for the preservation of environmentally sensitive land and resources, areas of historic significance and the provision of recreational facilities and services including: • Nine indoor RECenters with swimming pools, fitness rooms, gyms and class spaces. Cub Run features an indoor water park and on-site naturalist • Eight golf courses from par-3 to championship level, four driving ranges including the new state-of-the-art heated, covered range at Burke Lake Golf Center • Five nature and visitor centers. Also nine Off-Leash Dog Activity areas • Three lakefront parks including Lake Fairfax, Lake Accotink and Burke Lake, with campgrounds at Burke Lake and Lake Fairfax. The Water Mine Family Swimmin’ Hole at Lake Fairfax, Our Special Harbor Sprayground at Lee as well as an indoor water park at Cub Run RECenter • Clemyjontri Park, a fully accessible playground in Great Falls featuring two acres of family friendly fun and a carousel, as well as Chessie’s Big Backyard and a carousel at the Family Recreation Area at Lee District Park • An ice skating rink at Mount Vernon RECenter and the Skate Park in Wakefield Park adjacent to Audrey Moore RECenter • Kidwell Farm, a working farm of the 1930s-era at Frying Pan Farm Park in Herndon, now with historic carousel • Eight distinctive historic properties available for rent • A working grist mill at Colvin Run in Great Falls and a restored 18th century home at Sully Historic Site in Chantilly • A horticulture center at Green Spring Gardens in Annandale • Natural and cultural resources protected by the Natural Resource Management Plan and Cultural Resource Plans, plus an Invasive Management Area program that targets alien plants and utilizes volunteers in restoring native vegetation throughout our community • Picnic shelters, tennis courts, miniature golf courses, disc golf courses, off-leash dog parks, amphitheaters, a marina, kayaking/canoeing center • Provides 263 athletic fields, including 39 synthetic turf fields, and manages athletic field maintenance services at 417 school athletic fields. PARK AUTHORITY BOARD: A 12-member citizen board, appointed by the Fairfax County Board of Supervisors, sets policies and priorities for the Fairfax County Park Authority. Visit for Fairfax County Government's Comment Policy.

3 thoughts on “Lake Accotink Dam Fish Kill

  1. ansuseye

    I wrote the original e-mail alerting VDEQ to the situation. I am so glad Park Authorities from Fairfax County are so vigilant and concerned about our lakes and fish. If we don’t care for the planet and its creatures, its really our loss. I appreciate your thoughtful and excellently explained article. 🙂

  2. Don Waye

    I agree that fishing should be banned from this area, not just to minimize conflicts with trail users, but also to avoid the temptation of damming up the sluiceway. What about posting a “no fishing here” sign? The sign could include a notice that fishing is allowed along the lakeshore and along the natural creek bed. Consider also additional signage about not moving rocks to block the flow to the sluiceway and include a powerful photo of the recent fishkill. A picture tells a thousand words.

    1. Fairfax County Park Authority Post author

      Thank you for your comments and suggestions. This is an important community discussion and your input will be forwarded to staff.


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