Upper Loop Reservoir Reservoir Report

Last Updated: December 15, 2025

Upper Loop Reservoir, located in Malaga, Washington, is a private irrigation reservoir completed in 2015 with a storage capacity of 118 acre-feet.


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Summary

The dam, primarily used for irrigation purposes, is an earth-filled structure with a hydraulic height of 46.5 feet and a structural height of 39.5 feet. The reservoir is situated off-stream on the Tr-Stemilt river and is regulated by the Washington Department of Ecology, ensuring regular inspections, permitting, and enforcement to maintain its safety and functionality.

With a hazard potential rated as high, Upper Loop Reservoir has a satisfactory condition assessment as of the last inspection in September 2020. The emergency action plan was last revised in July 2015, and the reservoir meets regulatory guidelines for safety. The reservoir plays a crucial role in water management and irrigation in the region, highlighting the importance of sustainable water resource management in the face of changing climate patterns. As a key infrastructure in the area, Upper Loop Reservoir demonstrates the intersection of water resource management, climate resilience, and regulatory oversight in ensuring the safety and functionality of essential water storage facilities.

Year Completed

2015

Dam Length

1200

River Or Stream

Off stream, Tr- Stemilt

Primary Dam Type

Earth

Hydraulic Height

46.5

Nid Storage

118

Structural Height

39.5

Hazard Potential

High

Foundations

Soil

Nid Height

47
       
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.