Mill Pond Dam Reservoir Report
Last Updated: December 16, 2025
Mill Pond Dam, located in Durham, New Hampshire, stands as a concrete structure on the Oyster River, serving primarily for recreational purposes since its completion in 1935.
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Summary
With a modest height of 10 feet and a length of 140 feet, the dam provides a maximum storage capacity of 106 acre-feet and normal storage of 58 acre-feet, covering a surface area of 24 acres within a drainage area of 20 square miles. Despite its low hazard potential, the dam's condition assessment reflects a poor rating, indicating a need for maintenance and potential rehabilitation.
Maintained by the NHDES Dam Bureau and subject to state regulation, inspection, and enforcement, Mill Pond Dam has a spillway type of uncontrolled with a maximum discharge capacity of 1360 cfs. The dam's risk assessment is moderate, suggesting a level 3 risk, though specific risk management measures or a comprehensive emergency action plan have not been reported. With a designated inspection frequency of 6 years, the dam's last assessment in 2017 highlighted its poor condition, underscoring the importance of ongoing monitoring and necessary upgrades to ensure its structural integrity and safety for the surrounding community and ecosystem.
Year Completed |
1935 |
Dam Length |
140 |
Dam Height |
10 |
River Or Stream |
OYSTER RIVER |
Primary Dam Type |
Concrete |
Surface Area |
24 |
Drainage Area |
20 |
Nid Storage |
106 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
10 |
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.
Mill Pond Dam
Oyster River boat launch