Millen Lake Dam Reservoir Report
Nearby: Ashuelot Pond Dam Sand Pond Dam
Last Updated: December 15, 2025
Millen Lake Dam, located in Washington, New Hampshire, is a privately owned earth dam built in 1970 primarily for recreational purposes.
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Summary
Standing at 23 feet high and stretching 115 feet in length, this dam holds a storage capacity of 1,348 acre-feet and serves as a vital component of the local landscape. Situated on the TR Ashuelot River, the dam's uncontrolled spillway with a width of 5 feet ensures proper water flow management.
Despite its significant hazard potential, Millen Lake Dam has been deemed to be in satisfactory condition as of the last assessment in August 2015, with regular inspections conducted every four years. The dam's emergency action plan is being regularly updated and assessed for compliance with guidelines. With a moderate risk assessment rating of 3, the dam's risk management measures are continuously monitored to ensure the safety of the surrounding community and environment. For water resource and climate enthusiasts, Millen Lake Dam presents an interesting case study of dam infrastructure in a recreational setting within the picturesque Sullivan County, New Hampshire.
Year Completed |
1970 |
Dam Length |
115 |
Dam Height |
23 |
River Or Stream |
TR ASHUELOT RIVER |
Primary Dam Type |
Earth |
Surface Area |
156 |
Drainage Area |
1.23 |
Nid Storage |
1348 |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
23 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Millen Lake Dam
Millen Lake boat launch