Opp Dam; Marvin Reservoir Report
Last Updated: December 8, 2025
Opp Dam, located in Morton County, North Dakota, was completed in 2005 and serves as a crucial water resource for fire protection, livestock, and small fish pond purposes.
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Summary
Designed by DEHAAN, GRABS & ASSOC., this private dam stands at a height of 20 feet and has a storage capacity of 54.6 acre-feet, with a normal storage level of 33 acre-feet. The dam is primarily made of earth and stone materials and is regulated by the North Dakota State Water Commission, ensuring its safety and compliance with state regulations.
Despite its low hazard potential, Opp Dam is equipped with an uncontrolled spillway with a width of 18 feet to manage any excess water flow. While the dam has not been rated for its condition assessment, it remains under state inspection, enforcement, and permitting. With a moderate risk assessment rating of 3, the dam's risk management measures and emergency action plan status are currently not reported. Overall, Opp Dam stands as a vital infrastructure for water resource management in the region, contributing to the sustainability of the Bahr Creek-TR watershed.
Year Completed |
2005 |
Dam Height |
20 |
River Or Stream |
BAHR CREEK-TR |
Primary Dam Type |
Earth |
Surface Area |
5.74 |
Drainage Area |
0.65 |
Nid Storage |
54.6 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Opp Dam; Marvin