Williamson Gss No.1 Reservoir Report
Last Updated: December 13, 2025
Williamson Gss No.1 is a privately owned dam located in Garvin County, Oklahoma, along the TR-Washita River.
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Summary
Constructed in 1976 by the USDA NRCS, this earth-type dam stands at a height of 25 feet with a length of 350 feet, providing a storage capacity of 50 acre-feet. With a spillway type of "Controlled" and a maximum discharge of 400 cubic feet per second, this dam serves various purposes beyond just flood control, making it a critical water resource in the region.
While the dam has a low hazard potential, its risk assessment is deemed very high, highlighting the importance of proper management and maintenance. The dam is regulated by the Oklahoma Water Resources Board (OWRB), with state permitting, inspection, and enforcement in place to ensure its safety and functionality. Despite being ungraded in terms of condition assessment, the dam's emergency action plan (EAP) status is unclear, raising questions about its readiness in case of emergencies.
Overall, Williamson Gss No.1 plays a vital role in water resource management in the area, serving multiple purposes and providing essential storage capacity. As climate change continues to impact water resources, it is crucial to prioritize the safety and maintenance of such infrastructure to mitigate risks and ensure the continued availability of water for various uses.
Year Completed |
1976 |
Dam Length |
350 |
Dam Height |
25 |
River Or Stream |
TR-WASHITA RIVER |
Primary Dam Type |
Earth |
Surface Area |
7.2 |
Hydraulic Height |
25 |
Nid Storage |
50 |
Structural Height |
25 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Washita River Near Pauls Valley
|
327cfs |
Walnut Creek At Purcell
|
28cfs |
Canadian River At Purcell
|
201cfs |
North Criner Creek Near Criner
|
1cfs |
Washita River At Alex
|
236cfs |
Canadian River At Norman
|
213cfs |
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.
Williamson Gss No.1