Balch Afterbay Reservoir Report

Last Updated: December 5, 2025

Balch Afterbay, located in Fresno, California, near Balch Camp, is a private hydroelectric facility along the North Fork Kings River.


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Summary

Completed in 1928, this concrete dam stands at a height of 165 feet and has a storage capacity of 325 acre-feet. With a normal storage level of 317 acre-feet and a maximum discharge rate of 43,000 cubic feet per second, this dam plays a crucial role in water resource management in the area.

Managed by the Federal Energy Regulatory Commission, Balch Afterbay serves as a significant water storage and hydroelectric generation facility. Despite its age, the dam is considered to have a significant hazard potential, with a moderate risk rating of 3. Regular inspections by state and federal agencies ensure its structural integrity and compliance with safety regulations. The dam's uncontrolled spillway and multi-arch core design further highlight its importance in managing water flow in the region.

As a key component of the local water infrastructure, Balch Afterbay plays a vital role in regulating water levels and generating hydroelectric power. With its strategic location and design features, this dam stands as a testament to the engineering ingenuity of its time and continues to be a crucial asset in water resource management and climate resilience efforts in California.

Year Completed

1928

Dam Length

237.5

Dam Height

165

River Or Stream

North Fork Kings River

Primary Dam Type

Concrete

Surface Area

7

Hydraulic Height

164

Drainage Area

13

Nid Storage

325

Hazard Potential

Significant

Foundations

Rock

Nid Height

165
       
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.