Merrymeeting Lake Dam Reservoir Report
Last Updated: December 14, 2025
Merrymeeting Lake Dam, located in New Durham, New Hampshire, is a state-regulated structure on the Merrymeeting River.
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Summary
Completed in 1924, this earth dam stands at a height of 22 feet and has a length of 285 feet. The primary purpose of the dam is for recreation, with a normal storage capacity of 12,410 acre-feet and a maximum storage capacity of 14,933 acre-feet.
Despite its recreational significance, Merrymeeting Lake Dam poses a high hazard potential with a poor condition assessment. The dam has a moderate risk rating, with the last inspection conducted in October 2019. The dam is under the jurisdiction of the NHDES Dam Bureau, which oversees its permitting, inspection, and enforcement processes.
For water resource and climate enthusiasts, Merrymeeting Lake Dam offers an intriguing case study of a historic structure facing modern challenges. Its condition and risk assessment provide valuable insights into the ongoing efforts to ensure the safety and functionality of critical water infrastructure in the face of changing environmental conditions.
Year Completed |
1924 |
Dam Length |
285 |
Dam Height |
22 |
River Or Stream |
MERRYMEETING RIVER |
Primary Dam Type |
Earth |
Surface Area |
1241 |
Drainage Area |
10.7 |
Nid Storage |
14933 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
22 |
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.
Merrymeeting Lake Dam
Merrymeeting Lake boat launch