Holyoke - Overflow No. 3 Reservoir Report
Last Updated: December 6, 2025
Holyoke - Overflow No.
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Summary
3 is a historic masonry dam located in Holyoke, Massachusetts, constructed in 1860 for hydroelectric power generation and recreation purposes. The dam stands at a height of 20 feet, with a length of 100 feet, and a storage capacity of 26,000 acre-feet, serving the Holyoke Canal and covering a surface area of 2,290 acres. The dam's maximum discharge capacity reaches 1,935 cubic feet per second, managed through a controlled spillway with a width of 100 feet.
Operated by the local government and regulated by the Federal Energy Regulatory Commission, Holyoke - Overflow No. 3 has a low hazard potential but is recognized for its very high risk assessment ranking. The dam is equipped with four slide (sluice gate) outlet gates and has undergone inspections every three years, with the last assessment conducted in September 2017. Despite limited information on its current condition assessment, the dam remains a significant feature in the region's water resource management and climate resilience efforts.
With its rich history, dual utility for power generation and recreation, and strategic location within the Holyoke Canal, Holyoke - Overflow No. 3 stands as a testament to the intersection of human ingenuity and environmental stewardship. As water resource and climate enthusiasts, understanding and monitoring the structural integrity and regulatory oversight of such vital infrastructure is crucial for ensuring the safety and sustainability of our water systems in the face of changing climatic conditions.
Year Completed |
1860 |
Dam Length |
100 |
Dam Height |
20 |
River Or Stream |
Holyoke Canal |
Primary Dam Type |
Masonry |
Surface Area |
2290 |
Drainage Area |
8309 |
Nid Storage |
26000 |
Outlet Gates |
Slide (sluice gate) - 4 |
Hazard Potential |
Low |
Nid Height |
20 |
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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