Round Mountain Reservoir Report

Last Updated: December 5, 2025

Round Mountain is a privately owned dam located in Mendocino County, California, near the city of Ukiah.


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Summary

Built in 1964, this earth dam stands at a height of 43 feet and serves multiple purposes, including flood risk reduction, irrigation, recreation, and water supply. With a storage capacity of 282 acre-feet and covering a surface area of 17 acres, Round Mountain plays a crucial role in managing water resources in the region.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Round Mountain is subject to regular inspections and enforcement to ensure its structural integrity and safety. The dam's hazard potential is classified as high, but its condition assessment has been rated as satisfactory as of September 2017. The dam is designed to mitigate flood risks along the Tr York Creek and protect surrounding areas from potential inundation, highlighting its importance in water resource management and climate resilience efforts.

Despite its age, Round Mountain continues to play a vital role in the local water infrastructure, demonstrating the significance of proper maintenance and regulation of dams for flood control and water supply purposes. With its strategic location and key functions, Round Mountain serves as a crucial asset in safeguarding the community against potential water-related hazards and ensuring sustainable water management practices in the region.

Year Completed

1964

Dam Length

475

Dam Height

43

River Or Stream

Tr York Creek

Primary Dam Type

Earth

Surface Area

17

Hydraulic Height

35

Drainage Area

1.34

Nid Storage

282

Hazard Potential

High

Nid Height

43
       
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.