Cooper Lake Dam And West Dike Reservoir Report

Last Updated: December 6, 2025

Cooper Lake Dam and West Dike, located in Shady, Ulster, New York, serve as crucial components for water supply in the region.


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Summary

Owned by the local government and regulated by the NYS DEC, the dam stands at a height of 40 feet and stretches 460 feet in length. Completed in 1800, this earth-type dam boasts a storage capacity of 3683 acre-feet and covers a surface area of 241 acres, drawing water from the Saw Kill river.

Despite its age, the dam's condition assessment is deemed as poor with a high hazard potential, indicating a pressing need for maintenance and improvements. The spillway, with a width of 24 feet, remains uncontrolled, posing risks in case of extreme discharge events. The inspection frequency is set at 2 years, with the last assessment conducted in April 2020. With a moderate risk rating and a history of modifications undocumented, the dam's risk management measures and emergency action plans are yet to be fully established, raising concerns for potential safety hazards and environmental impacts.

Enthusiasts of water resources and climate in the area will find Cooper Lake Dam and West Dike to be a focal point for water supply infrastructure in Ulster, New York. With a rich history dating back to the 1800s, this dam faces challenges in its maintenance and risk management, highlighting the importance of continued monitoring and potential upgrades to ensure the safety and reliability of this vital water resource structure.

Year Completed

1800

Dam Length

460

Dam Height

40

River Or Stream

SAW KILL

Primary Dam Type

Earth

Surface Area

241

Drainage Area

0.7

Nid Storage

3683

Hazard Potential

High

Nid Height

40
       
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.