Square Butte Creek Dam 6 Reservoir Report
Last Updated: December 13, 2025
Square Butte Creek Dam 6, also known as Harmon Lake, is a local government-owned earth dam in Morton County, North Dakota.
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Summary
Completed in 2007 by the USDA NRCS, this dam serves primarily for recreational purposes and is regulated by the North Dakota State Water Commission. With a structural height of 80.7 feet and a maximum storage capacity of 8,297 acre-feet, Square Butte Creek Dam 6 is a significant water resource in the area.
Located on Otter Creek, this dam has a spillway width of 450 feet and a drainage area of 37.4 square miles. The dam's hazard potential is deemed significant, with a moderate risk assessment rating of 3. While the condition of the dam is currently not rated, inspections are conducted periodically to ensure its safety and integrity. With a surface area of 144 acres and a normal storage capacity of 2,399 acre-feet, Square Butte Creek Dam 6 plays a vital role in water management and recreation in the region.
Despite being a relatively new structure, Square Butte Creek Dam 6 has already become a key feature in the local landscape, providing both recreational opportunities and essential water management functions. With its stone core and soil foundation, this earth dam stands as a testament to the collaborative efforts of the USDA NRCS and the state regulatory agencies in ensuring the safety and efficiency of water resources in North Dakota.
Year Completed |
2007 |
Dam Length |
2100 |
Dam Height |
76.2 |
River Or Stream |
OTTER CREEK |
Primary Dam Type |
Earth |
Surface Area |
144 |
Drainage Area |
37.4 |
Nid Storage |
8297 |
Structural Height |
80.7 |
Outlet Gates |
None |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
81 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Burnt Creek Nr Bismarck
|
9cfs |
Heart River Nr Mandan
|
101cfs |
Missouri River At Bismarck
|
16700cfs |
Square Butte Creek Below Center
|
2cfs |
Hay Creek At Main Avenue In Bismarck
|
3cfs |
Sweetbriar Creek Nr Judson
|
3cfs |
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.
Square Butte Creek Dam 6
Burleigh County