Public Works and Environmental Services Alert:
The project was identified in the FY 2020 workplan due to repeated flooding at the intersection of North Albemarle Street and Chesterbrook Road and severe stream bank erosion upstream of this intersection. In October 2019, staff of the Stormwater Planning Division initiated the design of the project.
The project is being done in collaboration with the Virginia Department of Transportation (VDOT) to improve the storm sewer system within the VDOT road right-of-way. The Fairfax County Department of Transportation (FCDOT) is also managing a project to install a new sidewalk along Chesterbrook Road. FCDOT’s sidewalk project is being completed in phases. Phase 1 which extends from Kirby Road to Little Pimmit Run near Maddux Lane is complete.
Additional information on FCDOT’s sidewalk project is available at Chesterbrook Road Sidewalk (Chesterford Way to Maddux Lane).
The project assessed approximately 775 linear feet of an unnamed tributary to Little Pimmit Run near the Chesterbrook Road and North Albemarle Street intersection in McLean. The assessment resulted in a project scope that includes approximately 350 linear feet of stream below an outfall at Forest Lane, an additional 425 linear feet of stream between Woodland Terrace and North Albemarle Street, and approximately 225 linear feet of stream along Little Pimmit Run. The culvert at North Albemarle Street regularly has drainage issues with blockages caused by sediment and debris during larger storm events. The relatively low slope of this section prevents the sediment from moving through the pipe and may block the culvert contributing to flooding at the intersection.
The stream segments above and below the enclosed pipe are constrained by adjacent, privately owned land that have excessive erosion of the banks and stream channel incision. The lower reaches of the stream above the culvert at North Albemarle has more open land, is relatively flat and exhibits less erosion and instability. The purpose of the project is to restore the eroding channel to minimize the continued loss of sediment downstream, address flooding issues at the intersection of Chesterbrook Road and North Albemarle Street and improve water quality. The limits of the stream restoration project will be refined through the design iterations and may not include the full length of the assessed stream.
The primary goal of this restoration is to stabilize the channel and prevent future erosion and degradation along the stream. Drainage improvements at the intersection will alleviate future flooding. Restoration of native plantings will also be implemented after construction in order to promote diversity and the development of a healthy ecosystem. This project is part of Fairfax County’s larger efforts to restore many of the county’s degraded streams while also improving overall water quality and the condition of the Chesapeake Bay.
The stream restoration project is located between Forest Lane and North Albemarle Street with drainage improvements at the intersection of Chesterbrook Road and North Albemarle Street.
The project is in the Dranesville District and in the Pimmit Run Watershed.
