Mad River Flood Control Dam Reservoir Report

Last Updated: December 6, 2025

The Mad River Flood Control Dam, located in Winchester, Connecticut, was completed in 1963 and stands at a height of 178 feet with a length of 940 feet.


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Summary

This masonry dam serves the primary purpose of flood risk reduction along the Mad River, providing a maximum storage capacity of 11,300 acre-feet. With a high hazard potential, the dam is maintained by the state and regulated by the Connecticut Department of Energy and Environmental Protection (DEEP).

The dam's satisfactory condition assessment and regular inspections ensure its effectiveness in mitigating flood risks in the area. In the event of an emergency, an Emergency Action Plan (EAP) is in place, with the last revision in February 2017. The dam has a spillway width of 340 feet and a maximum discharge capacity of 29,600 cubic feet per second, making it a critical infrastructure for water resource and climate management enthusiasts in the region.

Overall, the Mad River Flood Control Dam is a vital structure for flood risk reduction in Litchfield County, Connecticut. Its strategic location and design contribute to the protection of surrounding communities from potential inundation and serve as a key component of water resource management efforts in the region. With state oversight and regular maintenance, this dam plays a crucial role in ensuring the safety and resilience of the area's water infrastructure in the face of changing climate conditions.

Year Completed

1963

Dam Length

940

Dam Height

178

River Or Stream

MAD RIVER

Primary Dam Type

Masonry

Surface Area

10

Drainage Area

18.2

Nid Storage

11300

Hazard Potential

High

Nid Height

178
       
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.