Union Pond Dam Reservoir Report

Last Updated: December 6, 2025

Union Pond Dam, located in Manchester, Connecticut, is a concrete structure completed in 1901 with a primary purpose of recreation.


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Summary

Standing at a height of 33 feet and spanning 590 feet in length, this dam has a storage capacity of 720 acre-feet and serves the surrounding area with a normal storage level of 515 acre-feet. The dam is situated on the Hockanum River and is under the regulatory oversight of the Connecticut Department of Energy and Environmental Protection (DEEP).

Despite its historical significance and recreational value, Union Pond Dam has been assessed as being in poor condition with a high hazard potential. The inspection frequency is set at every 2 years, with the last assessment conducted in August 2016. The dam's outlet gates consist of a slide (sluice gate) system. Given its condition and hazard potential, there is a need for regular monitoring and potential maintenance to ensure the safety and integrity of the structure.

In the event of an emergency, there is no information available regarding the existence or readiness of an Emergency Action Plan (EAP) for Union Pond Dam. With its high hazard potential, it is essential for local authorities and stakeholders to prioritize the development and implementation of an effective EAP to mitigate risks and protect downstream communities in case of a dam failure or emergency situation. Additionally, regular risk assessments and management measures should be considered to enhance the overall safety and resilience of Union Pond Dam.

Year Completed

1901

Dam Length

590

Dam Height

33

River Or Stream

HOCKANUM RIVER

Primary Dam Type

Concrete

Surface Area

51.5

Drainage Area

53.9

Nid Storage

720

Outlet Gates

Slide (sluice gate)

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

33
       
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.