Project Number: SD-000031-226
Public Works and Environmental Services Alert:
The stream stabilization and restoration project was identified in the Fiscal Year 2020 work plan and was originally included as a potential project in the Pimmit Run watershed plan. The project is in a wooded area, between a residential neighborhood and the George C. Marshall High School campus. The stream receives runoff from these areas and from portions of Tysons and Interstate 495. The stream channel exhibits eroded and over-widened banks, head-cuts and the potential for further bed and bank instability. There are also exposed sanitary sewer lines and failing storm drains along the stream channel and floodplain.
The project area is generally identified as a floodplain and a Resource Protection Area. The project will restore approximately 2,000 linear feet of degraded natural channel of Pimmit Run between a box culvert at Interstate 495 to a box culvert near Pimmit Run Lane, and approximately 300 linear feet of outfall leading to it. The project area stream drains about 256 acres of surrounding neighborhoods that includes communities upstream of Interstate 495. Restoration objectives include stream stabilization, water quality improvement, aquatic and riparian habitat enhancement, and reconnection of the channel with its floodplain. It is anticipated that the restoration will provide additional biological improvements with habitat features introduced to the restored stream channel and native vegetation plantings along the riparian corridor.
The stream restoration project is located along the headwaters of Pimmit Run, between Interstate I-495 and the box culvert near Pimmit Run Lane; after which the stream is piped for about one mile before it outfalls to a concrete channel east of Leesburg Pike (Route 7).
The project is in the Providence District and in the Pimmit Run Watershed.