Johnson Don Reservoir Report
Last Updated: December 8, 2025
Johnson Don is a private dam located in Cashion, Oklahoma, with a low hazard potential and a very high risk assessment rating.
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Summary
Built in 1965, this earth dam stands at a height of 24 feet and has a storage capacity of 100 acre-feet. It spans 660 feet in length and has a controlled spillway with a width of 1 foot. Despite being privately owned, Johnson Don is regulated by the Oklahoma Water Resources Board and undergoes regular inspections, with the last one conducted in January 2010.
Situated on TR-Cow Creek in Kingfisher County, Johnson Don plays a crucial role in water resource management in the area, with a maximum discharge capacity of 3800 cubic feet per second. The dam serves various purposes, although its primary function is categorized as "Other". With its valve outlet gate and capacity to hold 50 acre-feet of normal storage, Johnson Don contributes to flood control efforts and provides essential water resources for the surrounding community.
Climate and water resource enthusiasts will find Johnson Don to be a fascinating structure due to its unique design features, such as a stone core and soil foundation. The dam's location in the Tulsa District adds to its significance, underlining its importance in the local ecosystem. While its condition assessment is currently "Not Rated", ongoing risk management measures ensure that Johnson Don continues to operate safely and effectively, making it a noteworthy site for those interested in the intersection of water management and climate resilience.
Year Completed |
1965 |
Dam Length |
660 |
Dam Height |
24 |
River Or Stream |
TR-COW CR |
Primary Dam Type |
Earth |
Surface Area |
7 |
Hydraulic Height |
24 |
Nid Storage |
100 |
Structural Height |
24 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
24 |
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.
Johnson Don