Contoocook River Dam Reservoir Report

Last Updated: December 16, 2025

The Contoocook River Dam, located in Jaffrey, New Hampshire, was completed in 1861 and serves primarily for recreational purposes.


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Summary

This concrete dam stands at a height of 15 feet and has a length of 98 feet, providing a storage capacity of 60 acre-feet. The dam is owned by the Local Government and is regulated by the NHDES Dam Bureau, with state permitting, inspection, and enforcement in place to ensure its safety and integrity.

With a significant hazard potential and a moderate risk assessment score, the Contoocook River Dam is a vital structure for managing water resources in the area. The dam controls the flow of the Contoocook River, with a maximum discharge capacity of 3500 cubic feet per second. Despite its age, the dam has not been rated for its condition, and its Emergency Action Plan (EAP) is not up-to-date, raising concerns about emergency preparedness in case of a critical event.

As a key feature in the local water management system, the Contoocook River Dam plays a crucial role in providing recreational opportunities, regulating water flow, and mitigating flood risks. With ongoing monitoring and maintenance efforts, the dam continues to serve the community while facing challenges related to aging infrastructure and emergency response readiness. Enthusiasts of water resources and climate will find the Contoocook River Dam an intriguing case study in the intersection of infrastructure, environmental management, and public safety.

Year Completed

1861

Dam Length

98

Dam Height

15

River Or Stream

CONTOOCOOK RIVER

Primary Dam Type

Concrete

Surface Area

5

Drainage Area

21.2

Nid Storage

60

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

15
       
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.