Lake Thoreau Dam

TR-Snakeden Branch· Fairfax, Virginia· Earth· 56 ft tall

High Hazard Recreation Flood Risk Reduction Private

Key Takeaway

Lake Thoreau Dam is classified as high hazard in Virginia. Its primary use is recreation. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height	56 ft (taller than 95.2% in VA)
Dam Length	850 ft
Dam Type	Earth
Max Storage	1.4K acre-ft
Normal Storage	813 acre-ft

Surface Area	40 acres
Drainage Area	1 sq mi
NID ID	VA059013

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes

Last Inspection: February 9, 2021

State Regulated: Yes

Regulatory Agency: Department of Conservation and Recreation

Ownership

Reston Association;Reston Association

Private

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Fox Lake Dam

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Frequently Asked Questions

What is the hazard classification of Lake Thoreau Dam?

Lake Thoreau Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Lake Thoreau Dam?

Lake Thoreau Dam is owned by Reston Association;Reston Association (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

What is the primary purpose of Lake Thoreau Dam?

Lake Thoreau Dam serves the following purposes: Recreation, Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Lake Thoreau Dam?

Lake Thoreau Dam has a dam height of 56 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Lake Thoreau Dam last inspected?

Lake Thoreau Dam was last inspected on February 9, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.