Nubanusit Lake Dam Reservoir Report

Last Updated: December 19, 2025

Nubanusit Lake Dam, located in Nelson, New Hampshire, is a privately owned structure that serves the primary purpose of recreation.


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Summary

Completed in 1861, this earth dam stands at a height of 16 feet and has a length of 279 feet, impounding Nubanusit Brook to create a surface area of 733 acres. The dam has a normal storage capacity of 4,600 acre-feet and a maximum storage of 7,640 acre-feet, making it a significant water resource in the region.

Despite its age, the dam is in poor condition according to a 2015 assessment, with a hazard potential deemed significant. Although it is state regulated and inspected, with enforcement measures in place, the dam's risk assessment indicates a moderate level of risk. The last inspection in November 2019 revealed the need for improvement, and the dam's Emergency Action Plan was last revised in 1992. With its critical role in water management and recreation, ongoing maintenance and risk management measures are essential to ensure the safety and longevity of Nubanusit Lake Dam for future generations.

Year Completed

1861

Dam Length

279

Dam Height

16

River Or Stream

NUBANUSIT BROOK

Primary Dam Type

Earth

Surface Area

733

Drainage Area

6.49

Nid Storage

7640

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

16
       
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.