Florence Lake Reservoir Report

Last Updated: December 5, 2025

Florence Lake, located in Fresno, California, is a captivating destination for water resource and climate enthusiasts.


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Summary

Built in 1926, this concrete hydroelectric dam stands at a height of 149 feet and has a storage capacity of 68,000 acre-feet, making it a significant part of the Big Creek watershed. The dam not only serves the primary purpose of hydroelectric power generation but also offers recreational opportunities for visitors to enjoy the picturesque surroundings.

Managed by a private owner, Florence Lake is regulated by the Department of Water Resources (DWR) and undergoes regular inspections to ensure its safety and compliance with state regulations. The dam's spillway, with a controlled design and a width of 100 feet, adds to its impressive infrastructure. With a high hazard potential rating and a very high risk assessment, Florence Lake is closely monitored and equipped with emergency action plans to address any potential threats.

The dam's historical significance, architectural design, and contribution to the region's water resource management make Florence Lake a must-visit for those interested in the intersection of water infrastructure, climate resilience, and natural beauty. Whether exploring its engineering marvels, enjoying recreational activities on the lake, or learning about its environmental impact, Florence Lake offers a unique and enriching experience for enthusiasts seeking to delve into the world of water resources and climate conservation.

Year Completed

1926

Dam Length

3156

Dam Height

149

River Or Stream

Big Creek

Primary Dam Type

Concrete

Surface Area

962

Hydraulic Height

149

Drainage Area

171

Nid Storage

68000

Outlet Gates

Drum - 2

Hazard Potential

High

Foundations

Rock

Nid Height

149
       
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.