Holyoke Dam Reservoir Report

Last Updated: December 6, 2025

The Holyoke Dam, located in Holyoke, Massachusetts, stands as a testament to the power of hydroelectric energy generation and the beauty of the Connecticut River.


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Summary

Built in 1900, this masonry dam is primarily used for hydroelectric purposes, harnessing the river's flow to produce clean energy for the region. With a dam height of 30 feet and a length of 1770 feet, the Holyoke Dam boasts impressive engineering feats that have stood the test of time.

Surrounded by the picturesque Hampshire County, the Holyoke Dam not only serves as a source of renewable energy but also provides recreational opportunities for locals and visitors alike. The dam's controlled spillway, with a width of 1020 feet, ensures the safe management of water flow during periods of high discharge. The dam's storage capacity of 26,000 acre-feet and a surface area of 2290 acres further highlight its significance in managing water resources in the area.

Managed by the Federal Energy Regulatory Commission, the Holyoke Dam is subject to regular inspections to ensure its safety and compliance with regulations. With a significant hazard potential and very high risk assessment, the dam plays a crucial role in the region's water resource management and highlights the importance of sustainable and resilient infrastructure in the face of changing climates. For water resource and climate enthusiasts, the Holyoke Dam stands as a beacon of innovation and adaptation in the realm of renewable energy and environmental stewardship.

Year Completed

1900

Dam Length

1770

Dam Height

30

River Or Stream

Connecticut River

Primary Dam Type

Masonry

Surface Area

2290

Drainage Area

8309

Nid Storage

26000

Outlet Gates

Bascule - 1, Other Controlled - 5

Hazard Potential

Significant

Foundations

Rock

Nid Height

30
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.