Allen Reservoir Report

Last Updated: December 5, 2025

Allen is a significant earth-type dam located in Kelseyville, California, providing irrigation and water supply for the region.


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Summary

Built in 1955, it stands at a height of 33 feet with a storage capacity of 85 acre-feet. The dam is under state regulation and inspection by the Department of Water Resources, Safety of Dams division, ensuring its safety and compliance with regulations.

Situated on Tr Kelsey Creek, Allen plays a crucial role in managing water resources in Lake County. The dam has a satisfactory condition assessment and is deemed to have a significant hazard potential. Its location within the San Francisco District adds to its strategic importance in water management and conservation efforts. With a surface area of 11 acres and a drainage area of 0.8 square miles, Allen contributes to the overall water supply reliability in the region.

Owned privately, Allen's primary purpose is water supply, serving the community with essential irrigation and drinking water resources. The dam's structural integrity and operational efficiency are maintained through regular inspections, ensuring its continued role in sustaining water resources for the surrounding area. With its historical significance and ongoing importance in water management, Allen stands as a testament to the vital role of dams in ensuring water security and sustainability in California.

Year Completed

1955

Dam Length

250

Dam Height

33

River Or Stream

Tr Kelsey Cr

Primary Dam Type

Earth

Surface Area

11

Hydraulic Height

24.5

Drainage Area

0.8

Nid Storage

85

Hazard Potential

Significant

Nid Height

33
       
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.