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.