Prospect Lake Dam Reservoir Report

Last Updated: December 7, 2025

Prospect Lake Dam, located in Egremont, Massachusetts, is a private structure regulated by the Department of Conservation and Recreation.


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Summary

The dam, primarily used for recreation, stands at a height of 6 feet and has a hydraulic height of 4 feet. It holds a storage capacity of 437 acre-feet, with a normal storage of 350 acre-feet and a surface area of 57 acres. The dam is classified as a concrete gravity structure with a buttress core type, serving as a barrier for two unnamed perennial streams.

Despite its recreational purpose, Prospect Lake Dam is considered to have a significant hazard potential and has been assessed to be in poor condition as of October 2015. The dam, with a spillway type of uncontrolled, has not undergone any modifications in recent years and lacks emergency action plans. The inspection frequency for the dam is every 5 years, and it is located within the New England District of the US Army Corps of Engineers jurisdiction. With a moderate risk rating, the dam's risk management measures and risk characterization summary are currently unspecified. For water resource and climate enthusiasts, Prospect Lake Dam presents an intriguing case study in dam management and maintenance.

As discussions around climate change and water resource sustainability continue to grow, the condition and management of dams like Prospect Lake Dam are becoming increasingly important. The significance of maintaining infrastructure like this in good condition, with proper risk assessment and management measures in place, underscores the need for proactive approaches to safeguarding our water resources in the face of a changing climate.

Dam Length

300

Dam Height

6

River Or Stream

TWO UNNAMED PERENNIAL STREAMS

Primary Dam Type

Concrete

Surface Area

57

Hydraulic Height

4

Drainage Area

1.17

Nid Storage

437

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

6
       
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.