Bristol Reservoir #5 Dam Reservoir Report

Last Updated: December 5, 2025

Bristol Reservoir #5 Dam, located in Harwinton, Connecticut, is a key component of the water supply system for the city of Terryville.


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Summary

Completed in 1932, this earth dam stands at a height of 60 feet and stretches 640 feet in length. With a storage capacity of 866 acre-feet, it primarily serves the purpose of water supply, ensuring a reliable source of water for the area.

Managed by the local government and regulated by the state Department of Energy and Environmental Protection (DEEP), Bristol Reservoir #5 Dam has a high hazard potential but is currently rated as being in satisfactory condition as of the last assessment in October 2019. The dam overlooks the Poland River tributary and boasts a spillway width of 30 feet, providing a critical safety feature in case of excess water flow.

While the dam has not undergone significant modifications in recent years, regular inspections are conducted every two years to ensure its continued safety and functionality. With its strategic location and vital role in water resource management, Bristol Reservoir #5 Dam stands as a testament to the importance of sustainable water infrastructure in maintaining a resilient and reliable water supply system for the community.

Year Completed

1932

Dam Length

640

Dam Height

60

River Or Stream

POLAND RIVER TRIBUTARY

Primary Dam Type

Earth

Surface Area

34

Drainage Area

1.1

Nid Storage

866

Hazard Potential

High

Nid Height

60
       
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.