Elmer Stoplog Dam (Union) Reservoir Report

Last Updated: December 13, 2025

The Elmer Stoplog Dam in Union, Oregon, also known as Elmer #4, is a privately owned structure regulated by the Oregon Water Resources Department.


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Summary

Completed in 1975, this dam serves primarily for irrigation purposes on the Grande Ronde River. With a height of 10 feet and a length of 80 feet, the dam has a storage capacity of 298 acre-feet and a maximum discharge rate of 291 cubic feet per second.

Located in Imbler, Oregon, the Elmer Stoplog Dam plays a crucial role in managing water resources in the area, ensuring a stable water supply for agricultural activities. Despite being classified as having a low hazard potential, the dam undergoes regular inspections every six years to assess its condition and ensure its safety. The dam's emergency action plan status and risk assessment details are currently not rated, indicating a need for further evaluation and preparedness measures.

With its strategic position on the Grande Ronde River and its vital role in supporting irrigation activities, the Elmer Stoplog Dam stands as a significant water resource infrastructure in Union County. As climate change continues to impact water availability and management, the dam's efficient operation and maintenance are essential for safeguarding water resources in the region. Further developments in emergency response plans and risk assessment strategies can enhance the dam's resilience and ensure its continued effectiveness in water management for the local community.

Year Completed

1975

Dam Length

80

Dam Height

10

River Or Stream

GRANDE RONDE RIVER

Primary Dam Type

Other

Surface Area

86

Hydraulic Height

8

Drainage Area

0.4

Nid Storage

298

Structural Height

12

Outlet Gates

Slide (sluice gate)

Hazard Potential

Low

Nid Height

12
       
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.