Souhegan River Site 25b Dam Reservoir Report

Last Updated: December 17, 2025

The Souhegan River Site 25b Dam, also known as the General James Miller Dam, is a state-owned structure located in Temple, New Hampshire.


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Summary

Built in 1967 by the USDA NRCS, this earth dam stands at a height of 74 feet and spans 695 feet along Temple Brook. Its primary purpose is flood risk reduction, with a storage capacity of 1623 acre-feet and a maximum discharge capability of 15800 cubic feet per second.

Managed by the NHDES Dam Bureau, this dam is considered to have a high hazard potential and a fair condition assessment as of April 2018. Despite its moderate risk assessment, the dam is inspected every two years to ensure its structural integrity and compliance with state regulations. With a spillway width of 3 feet and no outlet gates, the Souhegan River Site 25b Dam plays a crucial role in mitigating flood risks in the Hillsborough County area.

Located in the picturesque Hillsborough countryside, the Souhegan River Site 25b Dam not only serves as a flood control measure but also supports the local ecosystem by regulating water flow in Temple Brook. With its historical significance and essential role in protecting downstream communities, this dam stands as a testament to the importance of water resource management and climate resilience in the region.

Year Completed

1967

Dam Length

695

Dam Height

74

River Or Stream

TEMPLE BROOK

Primary Dam Type

Earth

Surface Area

5.5

Drainage Area

5.39

Nid Storage

1623

Outlet Gates

None

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

74
       
Seasonal Comparison

Weather Forecast

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.