Siscowit Reservoir Dam Reservoir Report

Last Updated: December 5, 2025

Siscowit Reservoir Dam, located in Fairfield, Connecticut, serves as a crucial water supply source for the city of New Canaan.


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Summary

Built in 1865, this earth dam stands at a height of 6 feet and stretches 95 feet in length, with a storage capacity of 270 acre-feet. The dam is situated on the Rippowam River and is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP).

With a significant hazard potential, the dam has been assessed to be in satisfactory condition as of the last inspection in October 2017. The dam's spillway width of 90 feet ensures proper water flow management, while its location in a high-risk area highlights the importance of ongoing monitoring and maintenance. Despite its age, the Siscowit Reservoir Dam continues to play a vital role in providing safe and reliable water resources to the surrounding community.

Climate and water resource enthusiasts will find the Siscowit Reservoir Dam's history and engineering details intriguing, as it represents a lasting example of early infrastructure development in the region. Its presence on the Rippowam River underscores the interconnectedness of water management and environmental conservation efforts in Connecticut, making it a noteworthy site for those interested in sustainable water resource management practices.

Year Completed

1865

Dam Length

95

Dam Height

6

River Or Stream

RIPPOWAM RIVER

Primary Dam Type

Earth

Surface Area

4.5

Drainage Area

3.46

Nid Storage

270

Hazard Potential

Significant

Nid Height

6
       
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.