Tannahill Winnie G. Reservoir Report
Nearby: Kirten George No.2 Scs-Schaefer 1
Last Updated: January 12, 2026
Tannahill Winnie G., located in Harper County, Oklahoma, is a privately owned earth dam with a primary purpose of "Other." Built in 1960, this dam stands at a height of 28 feet and has a storage capacity of 110 acre-feet.
°F
°F
mph
Wind
%
Humidity
Summary
The dam is regulated by the Oklahoma Water Resources Board (OWRB) and is also subject to state jurisdiction, permitting, inspection, and enforcement.
Despite being classified as having a low hazard potential, Tannahill Winnie G. is considered to have a very high risk due to its location and characteristics. The dam has a controlled spillway type with a width of 1 foot and features a single valve outlet gate. While the condition assessment is currently listed as "Not Rated," the last inspection date was in August 2011, with inspections scheduled every 5 years.
For water resource and climate enthusiasts, Tannahill Winnie G. offers an intriguing case study in dam infrastructure management and risk assessment. With its unique design and regulatory oversight, this dam serves as a critical water management structure in the TR-TRADERS CR watershed. Its history, purpose, and risk profile provide valuable insights into the challenges and responsibilities associated with maintaining and monitoring dams in a changing climate.
Year Completed |
1960 |
Dam Length |
500 |
Dam Height |
28 |
River Or Stream |
TR-TRADERS CR |
Primary Dam Type |
Earth |
Surface Area |
3 |
Hydraulic Height |
28 |
Nid Storage |
110 |
Structural Height |
28 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
28 |
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.
Tannahill Winnie G.