Cheshire Mills Lower Dam Reservoir Report

Last Updated: December 18, 2025

Cheshire Mills Lower Dam, located in Harrisville, New Hampshire, was completed in 1848 and serves multiple purposes including fire protection, stock, and a small fish pond.


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Summary

The dam is made of stone with a buttress core type and stands at a height of 18 feet, with a length of 50 feet. It has a storage capacity of 1.8 acre-feet and a maximum discharge of 1097 cubic feet per second, making it a vital resource for water management in the area.

Although the dam is state-regulated and regularly inspected by the NHDES Dam Bureau, its condition assessment in 2015 deemed it unsatisfactory with a high hazard potential. Despite this, the risk assessment for the dam is moderate, indicating that management measures are in place to mitigate potential hazards. The emergency action plan for the dam was last revised in 2019, ensuring that proper protocols are in place in case of an emergency. Water resource and climate enthusiasts can appreciate the historical significance and ongoing management of the Cheshire Mills Lower Dam in sustaining water resources in the region.

Year Completed

1848

Dam Length

50

Dam Height

18

River Or Stream

NUBANUSIT BRROK

Primary Dam Type

Stone

Surface Area

0.1

Drainage Area

10

Nid Storage

1.8

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

18
       
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.