Danbury Dike No. 1 Reservoir Report

Last Updated: December 5, 2025

Danbury Dike No.


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Summary

1 in Connecticut stands as a crucial hydroelectric structure completed in 1929, with a height of 47 feet and the capacity to store up to 172,000 acre-feet of water. Serving primarily for hydroelectric purposes, this earth dam on the Rocky River spans 873 feet and covers a surface area of 5,600 acres. Despite its high hazard potential, the dam lacks a spillway and has not undergone recent condition assessments or emergency action plan updates.

Owned by a public utility, Danbury Dike No. 1 falls under the jurisdiction of the Federal Energy Regulatory Commission for regulation and inspections. While it boasts a rich history and significant water storage capabilities, the dam's risk assessment remains high due to its age and lack of modern safety features. With associated structures and a notable presence in Fairfield County, this dam plays a crucial role in water resource management and hydroelectric power generation in the region.

For water resource and climate enthusiasts, Danbury Dike No. 1 presents a fascinating case study of a historic earth dam with immense storage capacity and potential environmental impact. As discussions around infrastructure resilience and climate change adaptation continue, understanding the intricate details and risks associated with structures like this becomes crucial for ensuring sustainable water management practices in the face of evolving climatic conditions.

Year Completed

1929

Dam Length

873

Dam Height

47

River Or Stream

Rocky River

Primary Dam Type

Earth

Surface Area

5600

Drainage Area

40.4

Nid Storage

172000

Hazard Potential

High

Nid Height

47
       
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.