Croghan Island Dam Reservoir Report
Nearby: High Falls Upper Beaver Falls
Last Updated: December 19, 2025
Croghan Island Dam, located in Croghan, Lewis County, New York, is a privately owned concrete dam on the Beaver River that was completed in 1919.
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Summary
With a height of 12 feet and a length of 260 feet, this dam provides a normal storage capacity of 482 acre-feet and a maximum storage capacity of 797 acre-feet. The dam's surface area covers 121 acres, serving a drainage area of 293 square miles.
Despite being classified as having a low hazard potential and a moderate risk assessment, Croghan Island Dam is regulated, permitted, inspected, and enforced by the New York State Department of Environmental Conservation (NYS DEC). The dam's spillway, with a width of 180 feet, is uncontrolled. Although the dam's condition assessment is not rated, an Emergency Action Plan (EAP) was last revised in 2010. The dam is not owned or funded by any federal agency, making it a noteworthy example of a privately managed structure contributing to water resource management in the region.
For water resource and climate enthusiasts, Croghan Island Dam represents a historical and functional component of the Beaver River watershed. Its presence ensures water storage and management for the surrounding area, showcasing the importance of private ownership in maintaining essential infrastructure. With its long-standing history and ongoing regulatory oversight, this dam serves as a reminder of the critical role of dams in balancing water supply, flood control, and environmental protection in New York State.
Year Completed |
1919 |
Dam Length |
260 |
Dam Height |
12 |
River Or Stream |
BEAVER RIVER |
Primary Dam Type |
Concrete |
Surface Area |
121 |
Drainage Area |
293 |
Nid Storage |
797 |
Hazard Potential |
Low |
Nid Height |
12 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Croghan Island Dam