Otter Brook Dam Reservoir Report

Last Updated: December 15, 2025

Otter Brook Dam, also known as Otter Brook Lake, is a federal-owned structure located in Keene, New Hampshire.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1958 by the US Army Corps of Engineers, the dam serves primarily for flood risk reduction, with additional recreational purposes. Standing at a height of 119 feet and a length of 1288 feet, the gravity-type dam has a storage capacity of 24,800 acre-feet and a maximum discharge of 34,500 cubic feet per second.

Despite being classified with a high hazard potential, the dam is regularly inspected and monitored by the US Army Corps of Engineers to manage flood risks effectively. The agency continuously works on maintenance and repairs to ensure the structural integrity of the dam. In case of emergencies, an Emergency Action Plan is in place with updated guidelines and inundation maps to guide response efforts. The dam's risk management measures include engaging with local emergency managers and the public to raise awareness and readiness for potential dam-related emergencies.

In conclusion, Otter Brook Dam is a vital infrastructure for flood protection in the region, demonstrating the importance of proactive risk management and maintenance by the US Army Corps of Engineers to safeguard water resources and mitigate climate-related risks effectively.

Year Completed

1958

Dam Length

1288

Dam Height

119

River Or Stream

OTTER BROOK

Primary Dam Type

Gravity

Surface Area

76

Hydraulic Height

115

Drainage Area

47

Nid Storage

24800

Structural Height

119

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

119
       
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.