Quassapaug Lake Dam Reservoir Report

Last Updated: December 5, 2025

Quassapaug Lake Dam, located in Middlebury, Connecticut, was completed in 1900 and serves as a vital structure for water resource management and recreation in the area.


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Summary

This privately owned dam on Eightmile Brook has a height of 23.5 feet and a length of 125 feet, with a primary purpose of recreation. With a storage capacity of 2601 acre-feet and a surface area of 290 acres, Quassapaug Lake Dam provides a picturesque setting for outdoor activities and wildlife habitat.

The dam, constructed primarily of earth and stone, is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP) and undergoes regular inspections to ensure its safety and functionality. Despite having a fair condition assessment as of December 2019, the dam poses a significant hazard potential and is classified as having a moderate risk level. The presence of an uncontrolled spillway with a width of 14 feet adds to the complexity of managing water flow and potential flooding events in the area.

Overall, Quassapaug Lake Dam stands as a historic and essential structure for both water resource management and recreational purposes in New Haven County, Connecticut. With its beautiful surroundings and significant storage capacity, the dam serves as a reminder of the importance of sustainable water management practices in the face of changing climate conditions.

Year Completed

1900

Dam Length

125

Dam Height

23.5

River Or Stream

EIGHTMILE BROOK

Primary Dam Type

Earth

Surface Area

290

Drainage Area

1.82

Nid Storage

2601

Outlet Gates

None

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

24
       
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.