Lake Plymouth Reservoir Report

Last Updated: December 5, 2025

Lake Plymouth, located in Plymouth, Connecticut, is a picturesque water resource with a primary purpose of recreation.


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Summary

The dam at Lake Plymouth, built in 1900, stands at 7 feet tall and spans 280 feet in length, creating a storage capacity of 128 acre-feet. The lake covers a surface area of 32.1 acres and has a drainage area of 0.35 square miles, with a maximum discharge rate of 133 cubic feet per second.

Managed by a private owner, Lake Plymouth is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP) for permitting, inspection, and enforcement. The dam is classified as having a significant hazard potential and is currently assessed to be in fair condition as of the last inspection in April 2019. While there are no associated structures or locks, the spillway at Lake Plymouth has a width of 11 feet. Enthusiasts of water resources and climate will appreciate the recreational opportunities and scenic beauty offered by Lake Plymouth, making it a notable destination for outdoor activities in Litchfield County, Connecticut.

Year Completed

1900

Dam Length

280

Dam Height

7

River Or Stream

TODD HOLLOW BK TRIB

Primary Dam Type

Masonry

Surface Area

32.1

Drainage Area

0.35

Nid Storage

128

Hazard Potential

Significant

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.