Assumption Abbey Dam Reservoir Report

Last Updated: December 14, 2025

Assumption Abbey Dam, also known as Abbey Lake, is a privately owned structure located in Stark County, North Dakota.


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Summary

Completed in 1945, this earth dam stands at a height of 22.5 feet and has a length of 600 feet, providing fire protection and serving as a stock or small fish pond. With a storage capacity of 185.4 acre-feet and a surface area of 33.7 acres, the dam is situated along the Knife River-TR and is regulated by the North Dakota State Water Commission.

Although the dam has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment, it is subject to regular state inspections and enforcement measures. The spillway, with a width of 60 feet, is uncontrolled, and there are no outlet gates associated with the structure. Despite its moderate risk assessment score of 3, the dam does not fall under the jurisdiction of the US Army Corps of Engineers and has not been modified since its completion.

Water resource and climate enthusiasts may find Assumption Abbey Dam to be an intriguing case study of a privately owned earth dam that serves multiple purposes while posing a moderate risk in terms of potential hazards. Its location along the Knife River-TR and its history dating back to the mid-20th century make it a significant part of North Dakota's water infrastructure. The dam's association with fire protection, stock, and small fish pond functions highlight the diverse roles that such structures can play in managing water resources and supporting local ecosystems.

Year Completed

1945

Dam Length

600

Dam Height

22.5

River Or Stream

KNIFE RIVER-TR

Primary Dam Type

Earth

Surface Area

33.7

Drainage Area

1.56

Nid Storage

185.4

Structural Height

25

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

25
       
Seasonal Comparison

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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.