Dorris Dam Reservoir Report

Last Updated: December 5, 2025

Dorris Dam, located in Alturas, California, is a Federal-owned structure primarily used for irrigation purposes.


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Summary

Completed in 1930, this earth dam stands at a height of 25 feet with a hydraulic height of 23 feet and a length of 3860 feet. It has a storage capacity of 33,000 acre-feet and covers a surface area of 843 acres. The dam is situated on Stockdill Slough and is managed by the Fish and Wildlife Service.

The dam has undergone various modifications over the years, including in 1951, 1973, 1983, 2010, and 2018, to enhance its functionality and safety. It features uncontrolled spillways with a width of 72 feet and slide (sluice gate) outlet gates. Despite being classified as having a high hazard potential, the dam is currently assessed to be in fair condition as of the last inspection in July 2019.

With a moderate risk assessment rating, Dorris Dam plays a crucial role in managing water resources in the region. Its unique design and strategic location make it a key infrastructure for water supply and irrigation in Modoc County, California. Water resource and climate enthusiasts will find Dorris Dam to be a fascinating structure that contributes significantly to the local ecosystem and agricultural activities in the area.

Years Modified

1951 - Other, 1973 - Other, 1983 - Hydraulic, 2010 - Mechanical, 2018 - Other

Year Completed

1930

Dam Length

3860

Dam Height

25

River Or Stream

STOCKDILL SLOUGH

Primary Dam Type

Earth

Surface Area

843

Hydraulic Height

23

Drainage Area

16.6

Nid Storage

33000

Structural Height

25

Outlet Gates

Slide (sluice gate)

Hazard Potential

High

Foundations

Soil

Nid Height

25
       
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.
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