Foss Reservoir Report
Last Updated: December 6, 2025
Foss is a federal dam located in Clinton, Oklahoma on the Washita River, managed by the Bureau of Reclamation.
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Summary
Constructed in 1961, Foss serves as a flood risk reduction structure with a primary purpose of mitigating potential disasters in the region. Standing at a height of 142 feet and a length of 18,130 feet, Foss offers significant storage capacity, with a normal storage level of 168,732 acre-feet and a maximum storage capacity of 816,888 acre-feet.
The dam's spillway is controlled, with a width of 4 feet, and features a single valve as an outlet gate. Foss has a high hazard potential and is classified as having a very high risk assessment. Despite its critical role in flood risk reduction, the dam's condition assessment is currently listed as "Not Available," suggesting a need for further evaluation and maintenance to ensure its continued safety and efficacy. With its strategic location and significant storage capacity, Foss plays a vital role in water resource management and climate resilience efforts in the region.
As a key asset managed by the Bureau of Reclamation, Foss undergoes regular inspections, with the last inspection conducted in June 2020. The dam's Emergency Action Plan (EAP) status is not available, indicating a potential area for improvement in emergency preparedness and response. Despite these challenges, Foss remains a crucial infrastructure for flood control and water storage in Custer County, Oklahoma, highlighting the importance of continued monitoring and maintenance to safeguard the surrounding communities and environment from potential risks and hazards.
Year Completed |
1961 |
Dam Length |
18130 |
Dam Height |
142 |
River Or Stream |
WASHITA RIVER |
Primary Dam Type |
Earth |
Surface Area |
13141 |
Hydraulic Height |
128 |
Drainage Area |
1466 |
Nid Storage |
816888 |
Structural Height |
142 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
High |
Nid Height |
142 |
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.
Foss
Foss Reservoir Near Foss