Utica Auxiliary No. 5 Reservoir Report

Last Updated: December 5, 2025

Utica Auxiliary No.


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Summary

5, located in Alpine, California, along the North Fork Stanislaus River, is a privately owned rockfill dam with a primary purpose of hydroelectric power generation. Completed in 1903, this dam stands at 7 feet high and has a storage capacity of 2500 acre-feet, serving multiple purposes including recreation and water supply. The dam has a low hazard potential and is regulated by the Federal Energy Regulatory Commission, with state oversight from the Department of Water Resources for safety and inspection.

With a surface area of 233.5 acres and a drainage area of 15 square miles, Utica Auxiliary No. 5 has a maximum discharge capacity of 1100 cubic feet per second. The dam features an uncontrolled spillway with a width of 31 feet, and an inspection frequency of once per year to ensure its structural integrity. While the dam's condition assessment is currently not available, an Emergency Action Plan was last revised in December 2020, indicating proactive measures in place for potential emergencies.

Overall, Utica Auxiliary No. 5 plays a crucial role in water resource management and energy production in the region, showcasing the intersection of infrastructure, environmental conservation, and climate resilience. As a key component of the local hydroelectric system, this dam represents a balancing act between human development and natural ecosystems, highlighting the importance of sustainable water resource practices in the face of a changing climate.

Year Completed

1903

Dam Length

31

Dam Height

7

River Or Stream

North Fork Stanislaus River -

Primary Dam Type

Rockfill

Surface Area

233.5

Hydraulic Height

6

Drainage Area

15

Nid Storage

2500

Structural Height

6

Hazard Potential

Low

Nid Height

7
       
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.