Loon Pond Dam Reservoir Report

Last Updated: December 15, 2025

Loon Pond Dam, located in Lincoln, New Hampshire, is a concrete structure built for recreational purposes on Loon Pond Brook.


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Summary

It stands at 7 feet tall and has a length of 92 feet, providing a storage capacity of 57 acre-feet. Despite its low hazard potential, the dam is in poor condition according to a 2016 assessment, raising concerns about its long-term safety and effectiveness.

Managed by the NHDES Dam Bureau, the dam is state-regulated and undergoes regular inspections. Its spillway, which is uncontrolled, has a width of 92 feet and a maximum discharge capacity of 274 cubic feet per second. The surrounding area has a drainage area of 0.36 square miles, with a surface area of 19 acres. While the dam serves a primarily recreational purpose, its structural integrity and maintenance are critical for its continued operation and safety.

With its moderate risk assessment and poor condition, Loon Pond Dam highlights the importance of ongoing monitoring and maintenance efforts to ensure the safety of both the dam structure and the surrounding community. As a key asset for recreation in the area, it is essential that the necessary steps are taken to address the dam's current condition and prevent potential hazards in the future. The involvement of state regulatory agencies and periodic inspections are crucial in safeguarding the integrity of this important water resource in Grafton County, New Hampshire.

Dam Length

92

Dam Height

7

River Or Stream

LOON POND BROOK

Primary Dam Type

Concrete

Surface Area

19

Drainage Area

0.36

Nid Storage

57

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

7
       
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.