Florence Lake

About Florence Lake

The primary purpose of Florence Lake 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 Southern California Edison Company (private). It impounds the Big Creek near Mono Hot Springs.

The dam stands 149 feet tall and stretches 3,156 feet across, creates a reservoir covering 962 acres, has a maximum storage capacity of 68,000 acre-feet, and collects water from a drainage area of 171 square miles. Completed in 1926, the structure is well-established, with more than 75 years 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 08/30/2023.

At 149 feet, this dam is taller than 99% of all dams in the United States.

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 California dam safety program can provide more specific information about emergency planning for this structure.

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