This project was identified for stream restoration in the FY 2017 work plan as a result of the erosive stream conditions and frequency of maintenance required at the dam for accumulated sediment, woody debris and trash. In June 2018, staff of the Stormwater Planning Division initiated the design of the project.
The dry pond (1458DP) off Lewinsville Road requires frequent dredging due to the large amount of sediment washing up against the dam from streambank erosion. During rain events, the weir and embankment of the dry pond impound water across the site. Due to the impoundment, backwater conditions stop the flow of the stream channel. Additionally, litter from upstream culverts collects in the dry pond and requires frequent removal. A pre-conceptual design was completed in May 2019 and provided a design that addressed the trash and sediment deposition and included enhancing existing wetlands.
The primary goals of the restoration are:
Provide water quality enhancements by reducing sediment loads and enhancing floodplain connection
Provide a litter collection system
Improve and stabilize storm drain outfalls
Enhance existing wetlands
The project is located northeast of the Dulles Access Road exit ramp to Route 7, bounded by Lewinsville Road, Mayhurst Boulevard and Lewinsville Mews Court. This project starts at the Dulles Access Road and runs north to the downstream regional pond off Lewinsville Road.
Reduction in trash collection at dry pond 1548DP
Mitigate the backwater effect at dry pond 1548DP
Improvement of water quality through the removal of nitrogen, phosphorous and total suspended solids
Enhancement of existing wetlands
The project design was completed in May 2021.
What to Expect
Over the next several months, flagging and survey markers will be visible throughout the project area. Contractors and staff will primarily be on foot and wearing high-visibility clothing. Construction access and deliveries will most likely enter the site across the street from 8522 Lewinsville Road. Residents should expect periodic deliveries of material using dump trucks to the site throughout the week starting after 7 a.m. on weekdays. Work may occur on weekends; deliveries on those days will be made after 9 a.m.