Cooper Gp #8 Reservoir Report
Nearby: Cooper Gp #6 Cooper #23
Last Updated: December 21, 2025
Cooper Gp #8, located in Harper County, Oklahoma, is a privately owned earth dam constructed in 1960 by the USDA NRCS.
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Summary
Standing at a height of 25 feet with a length of 371 feet, this dam has a storage capacity of 74 acre-feet and serves a drainage area of 1.3 square miles. Despite being classified as having a low hazard potential, it poses a moderate risk due to its condition being "Not Rated" and lacking emergency action and inundation maps.
Managed by the Natural Resources Conservation Service, Cooper Gp #8 features an uncontrolled spillway with a width of 30 feet and is situated in the Tulsa District. With a primary purpose not specified, the dam's design and construction aim to provide crucial water resource management in the area. Although the dam does not have a state regulatory agency overseeing its operations, its moderate risk assessment underscores the importance of implementing risk management measures and emergency preparedness protocols to ensure the safety and integrity of this essential water infrastructure for the community in Fort Supply.
Year Completed |
1960 |
Dam Length |
371 |
Dam Height |
25 |
Surface Area |
1 |
Hydraulic Height |
25 |
Drainage Area |
1.3 |
Nid Storage |
74 |
Hazard Potential |
Low |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
North Canadian River At Woodward
|
59cfs |
Cimarron River Near Buffalo
|
75cfs |
Cimarron R Near Buttermilk
|
43cfs |
Bluff Creek Nr Buttermilk
|
43cfs |
Cimarron River Near Waynoka
|
133cfs |
North Canadian River Near Seiling
|
101cfs |
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.
Cooper Gp #8