Belden Dam Reservoir Report

Last Updated: December 5, 2025

Belden Dam, also known as Belden Pond, is a private dam located in Thompson, Connecticut, along the Blackmore Brook.


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Summary

Completed in 1900, this masonry dam stands at 12 feet high and spans 296 feet in length, with a storage capacity of 338 acre-feet. The dam primarily serves as a recreational site, offering a surface area of 75 acres for water activities and outdoor enjoyment.

Managed by the Connecticut Department of Energy and Environmental Protection (DEEP), Belden Dam is regulated, inspected, and enforced by the state to ensure its safety and compliance with regulations. With a significant hazard potential, the dam has a spillway width of 22 feet and a maximum discharge capacity of 60 cubic feet per second. Despite not being currently rated for its condition, the dam remains a key structure for water resource management in the region, attracting enthusiasts and visitors alike to its picturesque location in Windham County.

For water resource and climate enthusiasts, Belden Dam presents a fascinating example of historic engineering and recreational infrastructure in Connecticut. With its rich history, scenic surroundings, and state-regulated operations, the dam serves as a valuable asset for water storage, flood control, and outdoor recreation in the region. As efforts continue to ensure the safety and efficiency of the dam, it remains a prominent feature in the local landscape, drawing attention from those interested in the intersection of water resources, climate management, and recreational opportunities.

Year Completed

1900

Dam Length

296

Dam Height

12

River Or Stream

BLACKMORE BROOK

Primary Dam Type

Masonry

Surface Area

75

Drainage Area

1.59

Nid Storage

338

Hazard Potential

Significant

Nid Height

12
       
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.