Lake Needwood

About Lake Needwood

The primary purpose of Lake Needwood is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Mncppc-upper Rock Creek (local government). It impounds the Rock Creek near Twin Brook Forest.

The dam stands 65 feet tall and stretches 426 feet across, creates a reservoir covering 74 acres, has a maximum storage capacity of 7,023 acre-feet, and collects water from a drainage area of 12 square miles. Completed in 1965, the structure is well into its service life at over 50 years old.

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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 06/20/2024.

At 65 feet, this dam is taller than 96% of all dams in the United States.

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 Maryland dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.