Ellendale Water Supply Reservoir Report

Last Updated: December 13, 2025

Ellendale Water Supply, also known as Oster Dam, is a vital water resource in Dickey, North Dakota, owned by the local government and regulated by the North Dakota State Water Commission.


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Summary

Built in 1961, this earth dam on Dry Branch Creek stands at 14 feet tall and spans 1490 feet in length, providing a normal storage capacity of 379.1 acre-feet for the surrounding area. With a spillway width of 150 feet and one vertical lift outlet gate, the dam poses a significant hazard potential and is classified as having a moderate risk level.

Despite not being rated for condition assessment, Ellendale Water Supply undergoes regular inspections, with the most recent one conducted in May 2018. The dam is designed for water supply purposes and has a stone core on a soil foundation, serving as a crucial infrastructure for the community. The location of the dam, at the coordinates 45.96809 latitude and -98.52463 longitude, highlights its strategic position in the region and its importance in managing water resources. With its historical significance dating back to 1961, Ellendale Water Supply remains a key player in the local water management landscape.

Year Completed

1961

Dam Length

1490

Dam Height

14

River Or Stream

DRY BRANCH CREEK

Primary Dam Type

Earth

Surface Area

149.2

Drainage Area

52

Nid Storage

1987

Outlet Gates

Vertical Lift - 1

Hazard Potential

Significant

Foundations

Soil

Nid Height

14
       
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.