Harris Pond Dam Reservoir Report
Nearby: Supply Pond Dam Bowers Dam
Last Updated: December 17, 2025
Harris Pond Dam, located in Nashua, New Hampshire, is a privately owned structure regulated by the NHDES Dam Bureau.
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Summary
Built in 1870, this Earth-type dam stands at a height of 35 feet and spans 450 feet across Pennichuck Brook. Its primary purpose is water supply, with a storage capacity of 1,670 acre-feet and a drainage area of 25 square miles.
With a spillway width of 85 feet and a maximum discharge of 5,414 cubic feet per second, Harris Pond Dam is classified as having a high hazard potential. Despite this, the dam is currently in satisfactory condition as of the last assessment in November 2015. Regular inspections are conducted, with the most recent one taking place in June 2020, demonstrating a commitment to ensuring the safety and integrity of this vital water resource infrastructure.
While the risk assessment for Harris Pond Dam indicates a moderate level of risk, management measures and emergency action plans are not explicitly noted in the available data. As water supply remains a critical function of the dam, continued monitoring and maintenance will be key to preserving its functionality and safeguarding the surrounding community from potential hazards.
Year Completed |
1870 |
Dam Length |
450 |
Dam Height |
35 |
River Or Stream |
PENNICHUCK BROOK |
Primary Dam Type |
Earth |
Surface Area |
72 |
Drainage Area |
25 |
Nid Storage |
1670 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
35 |
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.
Harris Pond Dam
Greeley Ramp Road Nashua