Big Creek Reservoir Report

Last Updated: December 5, 2025

Big Creek, also known as Pine Mountain Lake, is a privately owned dam located in Jamestown, California.


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Summary

Completed in 1969, this earth-type dam stands at a height of 120 feet with a storage capacity of 7650 acre-feet. Its primary purpose is water supply, serving both recreational and water supply needs in the region.

Managed by the California Department of Water Resources and Safety of Dams, Big Creek is regulated, permitted, inspected, and enforced to ensure its safety and compliance with state regulations. With a hazard potential rated as high, the dam's condition assessment as of September 2017 was deemed satisfactory. Its last inspection in November 2020 indicated a need for regular monitoring and maintenance to mitigate any potential risks.

Situated in Tuolumne County, Big Creek spans an area of 200 acres and has a drainage area of 25.6 square miles. The dam's maximum discharge and spillway information were not provided, but its hydraulic height is recorded at 110 feet. With its strategic location and vital role in water supply, Big Creek is a crucial infrastructure that requires ongoing attention and management to ensure the safety and sustainability of the surrounding ecosystem and community.

Year Completed

1969

Dam Length

480

Dam Height

120

River Or Stream

Big Creek

Primary Dam Type

Earth

Surface Area

200

Hydraulic Height

110

Drainage Area

25.6

Nid Storage

7650

Hazard Potential

High

Nid Height

120
       
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.