Ashby Pond Dredging and Environmental Improvements

May 9, 2025, UPDATE: Dredging continues, and about 3/4 of the accumulated sediment and debris has been removed from the pond. Crews will now focus on constructing the restored inflow channels, starting with the channel on the northeast side of the pond. This eroded channel will be reconstructed with a series of step pools that will help dissipate the energy of stormwater flowing towards the pond. This part of the pond collects runoff from the Little River Hills subdivision. A sediment forebay will be constructed at the end of the inflow channel to collect sediment and debris. This smaller forebay is easier and more economical to maintain and increases the timeframe until the entire pond needs to be dredged.

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March 5, 2025, UPDATE: Construction crews have dewatered Ashby Pond in preparation for dredging. The turtle relocation conducted last summer was successful. No turtles have been caught in the pond since the project moved into the construction phase. Now that the water in the pond has been pumped out, crews are focusing on building a temporary construction access path around the perimeter of the pond. This will allow heavy equipment to reach all areas of the pond for tree removal and dredging. The primary focus in March will be completing the construction access path and tree removal.

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Feb. 3, 2025, UPDATE: Fairfax City Council awarded a construction contract to Sagres Construction in November 2024. Construction started in mid-January. The Ashby Pond Conservatory site will be closed to the public for the duration of construction, which will take approximately 12 months.

Jan. 9, 2025, UPDATE: Sagres Construction will begin mobilization on Jan. 21.

Sept. 11, 2024, UPDATE: A 40-pound snapping turtle was relocated. Watch this short video(External link).

July 22, 2024, UPDATE: Turtle relocation has concluded. Dr. Rimkus removed and relocated 55 turtles. Watch the video!(External link)

July 10, 2024, UPDATE: Turtle trapping will be postponed July 12-15 due to excessive heat. Trapping will resume July 16 at 10 a.m.

June 21, 2024, UPDATE: Some residents have asked what happens to the turtles when Ashby Pond is drained.

The city has contracted with Dr. Todd Rimkus from Marymount University to relocate turtles before the dredging and retrofit project starts this fall.

Dr. Rimkus has obtained a permit through the Department of Natural Resources to relocate turtles from Ashby Pond. Turtle traps are being tested now, and the relocation work will start in early-July and continue through the end of the month. [Jul 22. Turtle relocation has concluded.]

Turtle traps will be checked daily, and any captured turtles will be removed from the traps between 10 a.m. and 1 p.m. Residents are welcome to visit the pond during these times to see how trapping and relocation is performed. This is also a unique opportunity to observe the turtles more closely.

The DNR permit restricts handling of the turtles to the specific permittees, and the relocation work only requires a small group of people, so additional volunteers are not necessary to rescue the turtles.

You can learn more about Dr. Rimkus and the Hawksbill Hope nonprofit that he established for turtle conservation here: https://www.hawksbillhope.org/about/(External link)

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The City of Fairfax Department of Public Works is developing plans to dredge and upgrade Ashby Pond. Removing accumulated silt from the pond will increase the pond’s capacity to slow stormwater runoff and capture pollutants. The deeper pool will enhance water quality for local wildlife and improve the park’s aesthetics for visitors.

Satoshi Eto, public works program manager, explains the project to dredge and improve Ashby Pond.

A Pond with a Purpose

When it rains, stormwater runoff carrying sediment and debris flows downhill to Ashby Pond. The stormwater management pond receives runoff from about 135 acres, and much of the sediment is captured in the pond. Preventing pollutants from reaching Daniels Run improves the water quality in the Accotink Creek Watershed.

Dredging the pond is necessary about every 10 years to remove the silt that the pond captures over time. This restores the pond’s capacity to hold water capacity and its ability to continue to capture pollutants. The pond was last dredged in 2011; however, due to budgetary constraints, only a portion of the silt that had accumulated up to that point was removed.

Improving the Pond

In addition to dredging the pond, the department plans to retrofit the pond to meet current specifications. This work will increase the pond’s pollutant removal capabilities, make future maintenance easier and more economical, improve aesthetics, and provide the community with credits to help meet the city’s Chesapeake Bay pollutant reduction targets.

Environmental upgrades will include:

• repairing erosion at the two channels that flow into the pond and making them more resistant to erosion
• adding two sediment forebays that will trap sediment before it enters the main pond area
• adding aquatic benching and plantings around the perimeter of the pond

The sediment forebays will be easier to dredge in the future and greatly extend the intervals between dredging of the main pond. The aquatic benches create shallow water habitats for plants and animals.

Estimated Cost and Funding

This project will be partially paid for by the city's stormwater utility fee. The city was awarded $588,000 in Stormwater Local Assistance grant funding from the Virginia Department of Environmental Quality in 2021 to help pay for the $1.575M project.

In the months ahead the project team will continue to refine the design, seek and incorporate input from the community, and obtain necessary environmental permits. Construction is anticipated to begin in late 2024 and take 9-12 months to complete.