Lake Yosemite Reservoir Report

Last Updated: December 5, 2025

Lake Yosemite, also known as Yosemite Lake, is a public utility water supply located in Merced, California.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1888, this earth dam stands at 53 feet tall and stretches 4750 feet in length, with a storage capacity of 10,323 acre-feet. The reservoir covers an area of 500 acres and is fed by the nearby Tuolumne River. Managed by the California Department of Water Resources, the dam is regulated, inspected, and enforced for safety measures to ensure its satisfactory condition.

With its primary purpose being water supply for irrigation and municipal use, Lake Yosemite plays a crucial role in providing water resources to the surrounding communities. The dam's high hazard potential necessitates regular inspections, with the most recent being in May 2020, to ensure its structural integrity. Despite its age, the dam remains in satisfactory condition and meets regulatory guidelines, with emergency action plans in place for risk management.

Nestled within the picturesque landscape of Merced County, Lake Yosemite serves as a vital water source for agricultural and urban needs. Its historical significance, coupled with its strategic location near the Merced River, makes it a key player in the region's water management infrastructure. As climate change continues to impact water resources, Lake Yosemite stands as a beacon of resilience and sustainability in the face of environmental challenges.

Year Completed

1888

Dam Length

4750

Dam Height

53

River Or Stream

Tr Merced Rv

Primary Dam Type

Earth

Surface Area

500

Hydraulic Height

53

Drainage Area

4.95

Nid Storage

10323

Hazard Potential

High

Nid Height

53
       
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.