Public Works and Environmental Services

CONTACT INFORMATION: Our administrative offices are open 8 a.m. – 4:30 p.m., Mon - Fri
703-324-5500 TTY 711
12000 Government Center Parkway
Suite 449, Fairfax, Va 22035
Joni Calmbacher
Director, Stormwater Planning

Pimmit Run at George C. Marshall Drive Stream Restoration Project

Project Number: SD-000031-226

Eroded vertical banks moving toward Arrowhead Apartments
Eroded vertical banks moving toward Arrowhead Apartments
Collapsed concrete ditch at a storm drain outfall creating more than a 4-foot cut into the stream bed
Collapsed concrete ditch at a storm drain outfall creating more than a 4-foot cut into the stream bed

Project Update: April 15, 2024

A 65% design for the project is currently under review.

Project Background

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.

Project Description

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.

Project Location

map - Pimmit Run projectThe 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.

Project Benefits

  • Restoration of the ecological function of the stream corridor
  • Creation of a safe and sustainable stream valley for the community
  • Protection of surface waters, private property, and county infrastructure
  • Restoration of native vegetation and plant diversity
  • Stream stabilization and improvement in water quality including reduction in nutrients and sediment that flow downstream to the Potomac River and Chesapeake Bay
  • Improved habitat for wildlife

Project Timeline

A 65% design has been received and is under review. The project design work is scheduled to complete by November 2024. The Project is funded for design only. Construction is subject to budget allocations in future years.

What to Expect

County staffs and designers will be out occasionally to review the project area.

Project Cost and Funding Source

Restoring the section of Pimmit Run as part of this project is estimated to cost $3.95 million. Stormwater projects are funded through the county Stormwater Service District.

Presentations to the Community

Text about public meetings


For more information please email Project Manager Sajan Pokharel, Department of Public Works and Environmental Services, Stormwater Planning Division, or call (703) 324-5687, TTY 711.

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