Adder Reservoir Reservoir Report

Last Updated: December 5, 2025

Adder Reservoir, also known as Roaring Brook Reservoir, is a captivating water resource nestled in MIDDLETOWN, Connecticut.


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Summary

Built in 1934, this Earth dam stands at a height of 28 feet and spans 700 feet in length, holding a maximum storage capacity of 306 acre-feet. With a primary purpose of water supply, this reservoir serves as a critical component of the local government's infrastructure, regulated by the Department of Energy and Environmental Protection (DEEP) in Connecticut.

The reservoir's Hazard Potential is classified as High, but its Condition Assessment is rated as Fair, indicating a need for ongoing maintenance and monitoring. The last inspection in October 2020 revealed that the dam is in satisfactory condition, with regular inspections scheduled every 2 years. This key water source for the area covers a surface area of 34 acres and drains an area of 0.61 square miles, with a maximum discharge capacity of 349 cubic feet per second.

As a vital water supply resource for the community, Adder Reservoir plays a crucial role in ensuring water security and sustainability in the region. Its scenic location and historical significance make it a valuable asset for both water resource enthusiasts and climate advocates, highlighting the importance of responsible dam management and maintenance to safeguard this essential infrastructure for future generations.

Year Completed

1934

Dam Length

700

Dam Height

28

River Or Stream

ROARING BROOK

Primary Dam Type

Earth

Surface Area

34

Drainage Area

0.61

Nid Storage

306

Hazard Potential

High

Nid Height

28
       
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.