Lake Thoreau Dam

About Lake Thoreau Dam

The primary purpose of Lake Thoreau Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Reston Association;reston Association (private). It impounds the Tr-snakeden Branch.

The dam stands 56 feet tall and stretches 850 feet across, creates a reservoir covering 40 acres, has a maximum storage capacity of 1,406 acre-feet, and collects water from a drainage area of 0 square miles.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 02/09/2021.

At 56 feet, this dam is taller than 94% of dams nationwide.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Virginia dam safety program can provide more specific information about emergency planning for this structure.

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