Elmer Reservoir 1 (Union) Reservoir Report

Last Updated: December 14, 2025

Elmer Reservoir 1, located in Union, Oregon, is a private-owned water resource primarily used for irrigation purposes.


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Summary

Completed in 1966, this earth dam stands at 16 feet high and has a storage capacity of 128 acre-feet. Situated along the Grande Ronde River, the reservoir covers a surface area of 15 acres and serves as a crucial water source for agricultural activities in the region.

With a low hazard potential and a condition assessment of "Not Rated," Elmer Reservoir 1 is considered to be in good structural condition. The dam features a slide (sluice gate) outlet gate and has a hydraulic height of 12 feet. Despite not being regularly inspected, the reservoir meets state regulatory standards for permitting, inspection, and enforcement, ensuring its safe operation and maintenance.

Although the dam has not been modified in recent years and lacks certain emergency preparedness measures, Elmer Reservoir 1 remains a vital water infrastructure serving the irrigation needs of the local community. With its strategic location and reliable water storage capacity, the reservoir plays a crucial role in supporting agricultural activities and ensuring water resource sustainability in Union, Oregon.

Year Completed

1966

Dam Length

150

Dam Height

16

River Or Stream

GRANDE RONDE RIVER

Primary Dam Type

Earth

Surface Area

15

Hydraulic Height

12

Nid Storage

128

Structural Height

16

Outlet Gates

Slide (sluice gate)

Hazard Potential

Low

Nid Height

16
       
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.