Orwick Dam (Blm) Reservoir Report

Last Updated: December 5, 2025

Orwick Dam, located in Tehama County, California, is a federally owned structure managed by the Bureau of Land Management.


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Summary

Built in 1950 for irrigation purposes, this dam stands 22 feet tall and spans 421 feet in length, providing a storage capacity of 88 acre-feet. With a low hazard potential and a condition assessment that is not currently rated, Orwick Dam plays a crucial role in managing water resources in the region.

Despite not being regulated by the state, Orwick Dam has undergone periodic inspections, with the last one conducted in 2011. The dam is designed to handle a maximum discharge of 1 cubic foot per second and has a surface area of 12 acres. While its emergency action plan status and risk assessment details are not specified, the dam's operational responsibility, funding, and construction fall under the purview of the Bureau of Land Management, indicating a commitment to maintaining its integrity and safety.

The presence of Orwick Dam underscores the importance of water resource management in California, particularly for irrigation purposes. As a key piece of infrastructure in the San Francisco District, this dam serves as a vital component of the regional water supply system. With its historical significance and ongoing role in supporting agricultural activities, Orwick Dam remains a focal point for water resource and climate enthusiasts seeking to understand the intersection of human infrastructure and natural ecosystems.

Year Completed

1950

Dam Length

421

Dam Height

22

River Or Stream

NONE

Surface Area

12

Hydraulic Height

22

Drainage Area

1

Nid Storage

88

Hazard Potential

Low

Nid Height

22
       
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.