It may be time to repair the old dam.
The Fairfax County Board of Supervisors is calling a community meeting Thursday, Sept. 29 at 7:30 p.m., in the Bonnie Brae Elementary School cafeteria to discuss a possible rehabilitation project for the Lake Royal auxiliary spillway, or dam, located north of Guinea Road in Burke.
The average age of area dams is 35 years old, and the Lake Royal dam has been around for nearly 30 years, said Mat Lyons of the Natural Resources Conservation Service, a division of the U.S. Department of Agriculture. These dams have a 50-year design life, he said.
However, the boom in development and population of the Burke area over the past 35 years has created a "high hazard" for the dam, said Wade Biddix of the USDA.
"If the dam were to fail, it would have a lot of impact," said Biddix. Flooding would affect many houses in the residential area near Guinea Road and the lake, as well as the road itself and commuter traffic on it.
Supervisor Sharon Bulova (D-Braddock) said that it is unlikely that the dam would fail anytime soon. But state dam safety standards were tightened since the Lake Royal dam was built in 1976, making it below par today.
According to an information sheet prepared by Biddix and Lyons, the dam is structurally sound and its capacity is adequate, but the earth surface of the spillway is not strong enough to prevent erosion if the dam experienced a maximum rainwater event (just over 27 inches of rainfall in six hours, the size of a large hurricane).
"We're under the gun because the dam doesn't meet the standards it's supposed to meet," said Bulova at a preliminary meeting Thursday, Sept. 8 to discuss the Sept. 29 meeting.
"Public participation is a key element," said Diane Hoffman of the Northern Virginia Soil and Water Conservation District.
Bulova called for citizen input on options for dam rehabilitation. At the Sept. 29 meeting, she said, community leaders and community members will look at different possible options, from leaving the dam as-is to full rehabilitation, and many options in between.
"We're just getting started, so we have a lot of work to do," said Biddix.
— Lea Mae Rice