Hollow Dam Reservoir Report
Nearby: Emeryville Talcville
Last Updated: December 18, 2025
Hollow Dam, located on the West Branch Oswegatchie River in Talcville, New York, is a private concrete gravity dam primarily used for hydroelectric purposes.
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Summary
Completed in 1987, this multi-arch dam stands at a height of 31.2 feet and has a length of 385.5 feet, with a storage capacity of 220 acre-feet. The dam has a significant hazard potential and is inspected by the Federal Energy Regulatory Commission, with the last inspection conducted in June 2019.
With a drainage area of 294 square miles and a maximum discharge capacity of 10,000 cubic feet per second, Hollow Dam serves a critical role in managing water resources in the St. Lawrence County. The dam features an uncontrolled spillway with a width of 351 feet and vertical lift outlet gates. Despite its moderate risk assessment, the dam's condition assessment is currently listed as "Not Available," highlighting the importance of regular monitoring and maintenance to ensure its long-term functionality and safety.
As a key infrastructure for hydroelectric power generation in the region, Hollow Dam plays a vital role in supporting renewable energy production and water resource management. Its location in a scenic area surrounded by natural beauty adds to its significance, making it a focal point for water resource and climate enthusiasts interested in sustainable energy development and environmental conservation efforts in New York.
Year Completed |
1987 |
Dam Length |
385.5 |
Dam Height |
31.2 |
River Or Stream |
West Branch Oswegatchie River |
Primary Dam Type |
Concrete |
Surface Area |
16 |
Drainage Area |
294 |
Nid Storage |
220 |
Outlet Gates |
Vertical Lift - 3 |
Hazard Potential |
Significant |
Foundations |
Rock |
Nid Height |
31 |
Seasonal Comparison
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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.
Hollow Dam
Oswegatchie River