Stream restoration project starts this week in Annandale

Construction is expected to start this week on a stream restoration project in the Broyhill Crest neighborhood in Annandale. 

The Murray Lane Outfall Restoration Project will stabilize a 722-linear-foot section of an unnamed tributary of Holmes Run in the Cameron Run watershed. The project will increase capacity in the existing channel and stabilize the stream banks in an effort to reduce erosion and improve water quality.

The Fairfax County Department of Public Works and Environmental Services has contracted with Environmental Quality Resources LLC for the project. Construction is projected to last through October 2021.

The work will be conducted four days a week, 7 a.m.-4:30 p.m. Broyhill Crest Park, the garden plots at the end of the Lockwood Lane cul-de-sac, and the pedestrian bridge will remain open during construction. However, parking will be prohibited in the cul-de-sac.

Many trees will be removed, but the county promised the community “a massive native replanting” when the project is completed. 

That section of the stream “has a long history of maintenance concerns,” says Sharon North, spokesperson for the Fairfax County Department of Public Works and Environmental Services. 

The stream was realigned as part of the development of the Broyhill Crest subdivision in the 1950s. “Vertical walls were constructed in place of the original stream banks and the channel invert was lined with concrete,” North says. 

“Despite repeated stabilization efforts to address severe erosion and flooding issues, the stream continues to erode and portions of the walls and concrete invert are now failing in several areas,” she says.

As a result, the public sanitary sewer infrastructure is exposed within the channel, and the downstream end of the channel has failed, causing the natural channel downstream of Broyhill Crest to become too wide.

The project will draw on natural channel design concepts. The existing vertical walls will be replaced with a “channel in channel” design to improve floodplain capacity. 

The project also will protect property and public utility infrastructure, create in-stream and riparian habitat for wildlife, and improve water quality through the removal of phosphorus, nitrogen, and total suspended solids.