Upper Hart Pond Dam Reservoir Report

Last Updated: December 5, 2025

Upper Hart Pond Dam, located in Berlin, Connecticut, is a crucial water supply structure owned by the local government.


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Summary

Constructed in 1920, this Earth-type dam stands at a height of 12.5 feet and has a storage capacity of 168 acre-feet, serving the primary purpose of water supply. Situated along the Mattabesset River, the dam spans 1000 feet in length and covers a surface area of 24 acres, with a drainage area of 5.6 square miles.

Despite its satisfactory condition assessment as of November 2020, Upper Hart Pond Dam poses a high hazard potential, prompting regular inspections every two years. With a spillway type classified as "Uncontrolled" and a maximum discharge capacity of 375 cubic feet per second, the dam warrants ongoing risk management measures to ensure public safety and prevent potential inundation events. The dam's emergency action plan is crucial in addressing any unforeseen incidents and mitigating risks associated with its operation.

As a vital component of the local water infrastructure, Upper Hart Pond Dam not only provides essential water supply but also poses a moderate risk level that requires continuous monitoring and adherence to regulatory standards. With its historical significance dating back a century, this dam serves as a reminder of the importance of sustainable water resource management and climate resilience in the face of evolving environmental challenges.

Year Completed

1920

Dam Length

1000

Dam Height

12.5

River Or Stream

MATTABESSET RIVER

Primary Dam Type

Earth

Surface Area

24

Drainage Area

5.6

Nid Storage

168

Outlet Gates

Valve

Hazard Potential

High

Foundations

Soil

Nid Height

13
       
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.