Deering Reservoir Dam Reservoir Report

Last Updated: December 19, 2025

Deering Reservoir Dam, located in Deering, New Hampshire, serves as a critical water resource for the area, primarily used for recreation purposes.


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Summary

This earth-type dam, completed in 1940, stands at a height of 25 feet and spans 873 feet in length. With a maximum storage capacity of 3,143 acre-feet and a normal storage of 2,730 acre-feet, the dam plays a vital role in managing the flow of the Piscataquog River and supporting the surrounding ecosystem.

Maintained and regulated by the New Hampshire Department of Environmental Services Dam Bureau, the Deering Reservoir Dam has a high hazard potential but is currently rated as being in satisfactory condition. With its uncontrolled spillway and moderate risk assessment, the dam is subject to regular inspections, with the last one occurring in November 2020. Despite its potential risks, the dam continues to be a valuable asset for water resource management and recreational activities in the region.

As a significant structure in the Hillsborough County, New Hampshire, the Deering Reservoir Dam not only provides essential water storage but also serves as a recreational hub for the local community. With its strategic location along the Piscataquog River and the careful oversight of the state regulatory agencies, the dam stands as a testament to the importance of effective water resource management and climate resilience in the face of potential hazards.

Year Completed

1940

Dam Length

873

Dam Height

25

River Or Stream

PISCATAQUOG RIVER

Primary Dam Type

Earth

Surface Area

323

Drainage Area

4.3

Nid Storage

3143

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

25
       
Seasonal Comparison

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Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.