Plainville Reservoir Aka Crescent Lake Dam Reservoir Report

Last Updated: December 6, 2025

Located in Southington, Connecticut, the Plainville Reservoir, also known as Crescent Lake Dam, is a historic masonry dam completed in 1884 primarily for water supply purposes.


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Summary

With a height of 17 feet and a length of 688 feet, the dam has a storage capacity of 528 acre-feet and a surface area of 55 acres. It is situated on the Patton Brook Tributary and is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP).

The dam has a high hazard potential and is rated in fair condition as of the last assessment in July 2020. It is inspected every two years to ensure its structural integrity and safety. In case of emergencies, an Emergency Action Plan (EAP) may be in place, although the last revision date was in 2006. The dam is not associated with any federal agencies for ownership, funding, or construction, but it falls under the jurisdiction of the local government in Hartford County, Connecticut.

Plainville Reservoir serves as a vital water resource for the community, providing essential water supply for the region. Despite its age, the dam continues to play a crucial role in water management and conservation efforts. As climate change impacts water resources, monitoring and maintaining the integrity of dams like Crescent Lake Dam become increasingly important to ensure the safety and sustainability of water sources in the area.

Year Completed

1884

Dam Length

688

Dam Height

17

River Or Stream

PATTON BROOK TRIB

Primary Dam Type

Masonry

Surface Area

55

Drainage Area

0.39

Nid Storage

528

Hazard Potential

High

Nid Height

17
       
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.