Unruh Reservoir Dam Reservoir Report

Last Updated: December 16, 2025

Unruh Reservoir Dam, located in Whatcom County, Washington, is a privately owned structure managed by the Washington Department of Ecology.


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Summary

Built in 1959, this earth dam stands at a hydraulic height of 21 feet and serves primarily for irrigation purposes along Tr-Terrell Creek. With a storage capacity of 50 acre-feet, this low-hazard dam covers a surface area of 8.3 acres and has a drainage area of 0.3 square miles.

Although not rated for its condition assessment, Unruh Reservoir Dam is inspected by state regulatory agencies and meets state permitting and enforcement requirements. The dam features stone core types and soil foundations, with a length of 200 feet and a structural height of 15 feet. Despite its low hazard potential, the dam has a maximum discharge capacity of 325 cubic feet per second, ensuring efficient water management and control during periods of high flow.

For water resource and climate enthusiasts, Unruh Reservoir Dam presents a fascinating case study in private dam ownership and state regulation. Its strategic location and purposeful design for irrigation highlight the importance of sustainable water management in the region. As a key component of the local water infrastructure, the dam plays a crucial role in supporting agricultural activities and maintaining water supply reliability for the surrounding community.

Year Completed

1959

Dam Length

200

River Or Stream

Tr-Terrell Creek

Primary Dam Type

Earth

Surface Area

8.3

Hydraulic Height

21

Drainage Area

0.3

Nid Storage

50

Structural Height

15

Hazard Potential

Low

Foundations

Soil

Nid Height

21
       
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.