Pontoosuc Lake Dam Reservoir Report

Last Updated: December 9, 2025

Pontoosuc Lake Dam, located in Pittsfield, Massachusetts, was completed in 1866 and serves as a vital structure for the conservation of fish and wildlife in the area.


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Summary

This earth dam, with a height of 19 feet and a hydraulic height of 15 feet, creates a fish and wildlife pond with a normal storage capacity of 2650 acre-feet. The dam is situated on the West Branch Housatonic River and covers a surface area of 525 acres, providing recreational opportunities for locals and visitors alike.

Managed by the Department of Conservation and Recreation, Pontoosuc Lake Dam is regulated and inspected by the state of Massachusetts to ensure its structural integrity and safety. With a high hazard potential due to its location and condition assessment rated as satisfactory, the dam has an inspection frequency of every 2 years. In case of emergencies, an Emergency Action Plan is in place, last revised in June 2018, to mitigate risks and protect the surrounding community from potential inundation.

Despite its moderate risk assessment, Pontoosuc Lake Dam continues to be a key feature in the management of water resources and climate-related concerns in the Berkshire County region. As a significant landmark with historical value and ecological importance, the dam plays a crucial role in maintaining a balance between conservation efforts and recreational activities, making it a noteworthy site for water resource and climate enthusiasts to explore and appreciate.

Year Completed

1866

Dam Length

150

Dam Height

19

River Or Stream

WEST BRANCH HOUSATONIC RIVER

Primary Dam Type

Earth

Surface Area

525

Hydraulic Height

15

Drainage Area

21.7

Nid Storage

5000

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

19
       
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.