South Forebay Dike Reservoir Report
Last Updated: December 18, 2025
South Forebay Dike, located in Cornwall, New York, is a state-owned earth dam built in 1958 by Chas.
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Summary
T. Main for hydroelectric and navigation purposes along the St. Lawrence River. The dam stands at a height of 136 feet and spans a length of 8400 feet, with a storage capacity of 803,000 acre-feet and a surface area of 37,500 acres. Despite being state-regulated, the dam has a high hazard potential and is under the jurisdiction of the Federal Energy Regulatory Commission for inspections and regulatory oversight.
The South Forebay Dike is part of a network of six associated structures, contributing to the overall water management and power generation in the region. With a drainage area of 300,000 square miles, the dam plays a crucial role in controlling water flow and ensuring the safety of downstream communities. Although the condition assessment is not available, the dam has a risk assessment rating of high (2), emphasizing the importance of regular inspections and maintenance to prevent potential hazards and ensure structural integrity.
Given its significance for hydroelectric power generation and water resource management, South Forebay Dike serves as a vital infrastructure in the region. With Elise M. Stefanik (R) representing the area in Congress, ongoing efforts are needed to address any potential risks and ensure the continued safety and efficiency of the dam for both environmental and economic sustainability in the face of changing climate conditions.
Year Completed |
1958 |
Dam Length |
8400 |
Dam Height |
136 |
River Or Stream |
St. Lawrence River |
Primary Dam Type |
Earth |
Surface Area |
37500 |
Drainage Area |
300000 |
Nid Storage |
803000 |
Structural Height |
55 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
136 |
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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