The design task order was authorized on June 18, 2026. Survey and assessment activities will begin the week of August 3, 2026.
Eroded vertical banks along the stream channel.
Project Background
The proposed stream stabilization and restoration project is located within the Pimmit Run Watershed in McLean. The project is in a wooded area and extends approximately 2,700 linear feet from the intersection of MacArthur Drive and Halsey Road to Park Road. The stream channel exhibits significant erosion, head-cuts and the potential for further bed and bank instability.
Project Description
The project includes restoration of approximately 2,700 linear feet of Pimmit Run, its tributaries and stormwater outfalls.
The goal of the project is to implement a sustainable project for the protection of property, health and safety, and improvement of water quality. This goal will be accomplished by restoring the stream’s dimension, pattern and profile to a form that is appropriate for current and future hydrologic conditions of the watershed. The proposed project will restore equilibrium to the channel and riparian corridor, allow for the effective conveyance of water and sediment without excessive channel erosion and migration, enhance the habitat, improve species diversity and restore the ability of the channel and its floodplain to naturally process excess nutrients and sediment. The proposed project will also maximize the preservation of existing trees and soil and will repurpose the fallen trees and existing streambed material within the restoration project.
Project Location
The project is located within the Pimmit Run Watershed in the Dranesville District, McLean. The project is bounded by a culvert under Park Road on the east and the intersection of MacArthur Drive and Halsey Road to the west.
Project Phase
The project is in the Pre-design Phase.
Project Benefits
The primary goals of the restoration are:
Improve Water Quality
Stabilize streambed and banks
Reduce sediment and nutrient inputs into stream system
Installation of grade control structures, channel dimension and alignment
Improve floodplain connectivity and ecological processes
Increase frequency and residence time of water on floodplain
Reduce force and volume of water within the channel during storm and flood events
Naturally process nutrients and sediments on the floodplain and within the streambed
Resilient and regenerative design of riparian system
Improve habitat for biological community
Native landscaping
Floodplain wetlands
Streambed and flow diversity
Protect private property and infrastructure (sanitary, water, etc.)
Engage with affected homeowners throughout project development
What to Expect
As the project advances through the iterative design development process, community meetings will be scheduled to present the project and its design to the residents along the project and receive feedback from the community. Meetings will be scheduled for the 35% design, 65% design, 95% design and prior to the start of construction.
Eroded stream channel with exposed sanitary manhole.
Project Cost and Funding Source(s)
Design of the Little Pimmit Run near MacArthur Drive stream restoration project has been funded for $713,000. Construction funding is dependent upon future budget availability and allocations. Stormwater projects are funded through the county Stormwater Service District.
Contact
For more information, please email the Project Manager Heather Ambrose, Stormwater Planning Division, Department of Public Works and Environmental Services, or call -703-324-5500, TTY 711.