Big Coulee Dam Reservoir Report
Nearby: Snyder Lake Dam Pleasant Valley Dam
Last Updated: December 13, 2025
Big Coulee Dam, also known as Bisbee Dam, is a local government-owned structure located in Towner, North Dakota.
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Summary
Completed in 1968 by the NDSWC, this earth dam stands at a height of 36 feet and stretches 1170 feet in length. With a primary purpose of recreation, the dam offers a storage capacity of 5103 acre-feet and a surface area of 240 acres, making it a popular destination for water resource and climate enthusiasts.
This significant dam on the Big Coulee River is regulated by the NDSWC and undergoes regular inspections to ensure its safety and functionality. The spillway, with a width of 205 feet, is uncontrolled, adding to the dam's hazard potential which is rated as significant. Despite its moderate risk assessment, the dam's condition assessment remains unrated, indicating a need for further evaluation. With a valve outlet gate and a history of modifications in 1985 for structural improvements, the Big Coulee Dam continues to serve its purpose while being monitored for any potential risks or issues.
Overall, the Big Coulee Dam stands as a testament to engineering ingenuity and plays a vital role in providing recreational opportunities while managing water resources in the region. With its picturesque location in Towner, North Dakota, this earth dam serves as a hub for outdoor activities and serves as a reminder of the importance of maintaining and inspecting critical infrastructure for the safety and well-being of the community.
Years Modified |
1985 - Structural |
Year Completed |
1968 |
Dam Length |
1170 |
Dam Height |
36 |
River Or Stream |
BIG COULEE |
Primary Dam Type |
Earth |
Surface Area |
240 |
Drainage Area |
108 |
Nid Storage |
5103 |
Structural Height |
39 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
39 |
Seasonal Comparison
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Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Big Coulee Dam