Unknown Reservoir Report
Last Updated: December 13, 2025
Located in Osage, Oklahoma, the dam known as "Unknown" was completed in 1940 and stands at a height of 38 feet with a hydraulic height of 35 feet.
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Summary
This Earth-type structure, primarily used for purposes other than flood control or water supply, holds a storage capacity of 340 acre-feet and covers a surface area of 4 acres. Despite its low hazard potential, the risk assessment for this dam has been classified as very high.
Owned and regulated by a private entity, the Unknown dam falls under the jurisdiction of the Oklahoma Water Resources Board (OWRB) and is subject to state permitting, inspection, and enforcement. With a controlled spillway type and a single valve outlet gate, this dam poses minimal risk to downstream areas. However, its condition assessment remains unrated, and there is limited information available regarding its emergency action plan and risk management measures.
Although the Unknown dam has not been significantly modified since its completion, it is important for water resource and climate enthusiasts to monitor its condition and potential risks closely. With the potential for high-risk scenarios despite its current hazard rating, continued assessment and oversight are crucial to ensuring the safety and integrity of this structure in the future.
Year Completed |
1940 |
Dam Length |
120 |
Dam Height |
38 |
River Or Stream |
TR-BUCK CR |
Primary Dam Type |
Earth |
Surface Area |
4 |
Hydraulic Height |
35 |
Nid Storage |
340 |
Structural Height |
38 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
38 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Caney R Nr Elgin
|
37cfs |
Caney River Above Coon Creek At Bartlesville
|
63cfs |
Elk R At Elk Falls
|
32cfs |
Hominy Creek Near Hominy
|
2cfs |
Bird Creek At Avant
|
8cfs |
Arkansas River At Ralston
|
3620cfs |
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.
Unknown