Holyoke - Overflow No. 2

About Holyoke - Overflow No. 2

The primary purpose of Holyoke - Overflow No. 2 is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by City Of Holyoke Gas And Electric Department (local government). It impounds the Holyoke Canal near Holyoke.

The dam stands 30 feet tall and stretches 105 feet across, creates a reservoir covering 2,290 acres, has a maximum storage capacity of 26,000 acre-feet, and collects water from a drainage area of 8,309 square miles. Completed in 1860, the structure is one of the older dams in the region, with over a century and a half of service.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 08/11/2022.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Massachusetts dam safety program can provide more specific information about emergency planning for this structure.

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