Deweese #11 Reservoir Report
Nearby: Deweese Gp-12 Kinney #3
Last Updated: December 21, 2025
Deweese #11 is a privately owned earth dam located in Harper County, Oklahoma, near the city of Fort Supply.
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Summary
Built in 1959 by the USDA NRCS, this dam spans 124 feet in length and stands at a height of 39 feet, with a storage capacity of 50 acre-feet. Situated on Sand Creek, this structure serves as a vital resource for water management in the region, with a drainage area of 0.23 square miles.
Despite its age, Deweese #11 maintains a low hazard potential and is considered to be in moderate condition. With an uncontrolled spillway width of 35 feet, this dam has not undergone recent inspections or assessments. Although it is not regulated by the state, Deweese #11 plays a crucial role in flood control and water storage for the surrounding area. As climate change continues to impact water resources, the maintenance and upkeep of structures like Deweese #11 will be essential for ensuring sustainable water management practices in Oklahoma.
As water resource and climate enthusiasts, it is important to recognize the significance of structures like Deweese #11 in managing water supply and mitigating flood risks in the region. With a storage capacity of 50 acre-feet and a moderate risk assessment rating, this earth dam continues to play a vital role in the local water infrastructure. As climate change presents new challenges for water resource management, it will be crucial to monitor and maintain structures like Deweese #11 to ensure the resilience of water systems in Harper County, Oklahoma.
Year Completed |
1959 |
Dam Length |
124 |
Dam Height |
39 |
River Or Stream |
SAND CREEK |
Primary Dam Type |
Earth |
Surface Area |
3 |
Hydraulic Height |
39 |
Drainage Area |
0.23 |
Nid Storage |
50 |
Hazard Potential |
Low |
Nid Height |
39 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Cimarron River Near Buffalo
|
75cfs |
North Canadian River At Woodward
|
59cfs |
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.
Deweese #11