Ilion Reservoir #3 Dam Reservoir Report
Last Updated: December 7, 2025
Ilion Reservoir #3 Dam, located in Ilion, New York, is a crucial water supply infrastructure owned by the local government and regulated by the New York State Department of Environmental Conservation.
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Summary
Built in 1921, this earth dam stands at a height of 76 feet and spans 975 feet in length, providing a capacity of 737 acre-feet for water storage. The dam's primary purpose is water supply, serving the community's needs efficiently.
With a surface area of 41 acres and a drainage area of 1.2 square miles, Ilion Reservoir #3 Dam plays a vital role in managing water resources in the region. The dam features an uncontrolled spillway with a width of 59 feet, ensuring proper water release during high flow events. Although the dam's hazard potential is considered high, its condition assessment is rated as fair, reflecting ongoing maintenance and monitoring efforts to ensure public safety and operational efficiency.
Despite its age, Ilion Reservoir #3 Dam has maintained a moderate risk assessment level, indicating a proactive approach to risk management and emergency preparedness. Regular inspections and assessments are conducted to monitor the dam's condition, with the last assessment performed in October 2020. As a key component of the local water supply infrastructure, this dam exemplifies the importance of sustainable water resource management in the face of changing climate conditions.
Year Completed |
1921 |
Dam Length |
975 |
Dam Height |
76 |
River Or Stream |
TR-MOHAWK RIVER |
Primary Dam Type |
Earth |
Surface Area |
41 |
Drainage Area |
1.2 |
Nid Storage |
737 |
Hazard Potential |
High |
Nid Height |
76 |
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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