Rock Island Dam Reservoir Report
Last Updated: December 10, 2025
Rock Island Dam, located in Port Leyden, New York, is a privately owned concrete dam on the Black River with a primary purpose of hydroelectric power generation.
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Summary
Completed in 1984, this 12-foot tall structure spans 96 feet in length and has a normal storage capacity of 50 acre-feet. With a low hazard potential and a moderate risk assessment rating, the dam is regulated by the New York State Department of Environmental Conservation (NYS DEC) and undergoes regular inspections to ensure its safety and integrity.
The dam features an uncontrolled spillway with a width of 96 feet and is situated within the Lewis County, New York area. Owned and operated by private entities, Rock Island Dam plays a crucial role in harnessing the power of the Black River for renewable energy production. Despite its low hazard potential, the dam's risk assessment rating underscores the importance of diligent risk management measures to mitigate any potential impacts on the surrounding environment and communities.
Rock Island Dam remains a significant infrastructure for the region's water resource management and climate resilience efforts. With its hydroelectric capabilities and state-regulated operations, the dam serves as a vital component in the sustainable utilization of water resources for energy production in New York. As climate change continues to pose challenges to water availability and management, the presence of structures like Rock Island Dam highlights the importance of responsible dam ownership and maintenance to ensure the long-term sustainability of our water systems.
Year Completed |
1984 |
Dam Length |
96 |
Dam Height |
12 |
River Or Stream |
BLACK RIVER |
Primary Dam Type |
Concrete |
Surface Area |
8 |
Drainage Area |
428 |
Nid Storage |
50 |
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.
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