Hillside Reservoir Report

Last Updated: December 5, 2025

Hillside, also known as South Lake, is a privately-owned hydroelectric dam located in Bishop, California.


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Summary

Built in 1910 by designers Manifold and Poole, this rockfill dam stands at a height of 81.5 feet and has a storage capacity of 12,883 acre-feet. With a primary purpose of hydroelectric power generation, the dam also serves for recreational activities in the area.

Regulated by the California Department of Water Resources and inspected regularly by the Federal Energy Regulatory Commission, Hillside poses a high hazard potential due to its location on the South Fork Bishop Creek. The dam features an uncontrolled spillway and has a maximum discharge capacity of 1,700 cubic feet per second. Despite its age, Hillside's risk assessment is considered moderate, with emergency action plans in place to mitigate potential hazards.

Although its condition assessment is currently unavailable, Hillside remains a vital water resource infrastructure in Inyo County. With its scenic location and historical significance, this dam continues to play a crucial role in balancing water management, hydroelectric power generation, and recreational opportunities in the region. As climate change impacts water resources, the maintenance and monitoring of dams like Hillside become increasingly important for sustainable water management practices.

Year Completed

1910

Dam Length

645

Dam Height

81.5

River Or Stream

South Fork Bishop Creek

Primary Dam Type

Rockfill

Surface Area

173

Drainage Area

13.1

Nid Storage

12883

Structural Height

81.5

Hazard Potential

High

Foundations

Rock

Nid Height

82
       
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.