Thomas Number 1 Reservoir Report
Nearby: Thomas Number 2 Hix Number 3
Last Updated: December 9, 2025
Thomas Number 1 is a privately owned dam located in Jones, South Dakota, along the TR-White River.
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Summary
Constructed in 1955 by the Natural Resources Conservation Service, this earth dam stands at a height of 27 feet and stretches 771 feet in length. With a storage capacity of 43 acre-feet and a maximum discharge of 1197 cubic feet per second, Thomas Number 1 serves as a vital water resource infrastructure in the area.
Despite being categorized as having a low hazard potential, Thomas Number 1 is regulated by the South Dakota Department of Environmental and Natural Resources. The dam is regularly inspected, permitted, and enforced to ensure its structural integrity and safety. While its condition is currently not rated, the dam is equipped with emergency action plans, although details on their preparation and implementation are not publicly available.
With its strategic location and importance in water resource management, Thomas Number 1 plays a crucial role in the local ecosystem and community. As water resource and climate enthusiasts, understanding the intricate details and regulatory measures surrounding dams like Thomas Number 1 is essential for ensuring sustainable water management practices and safeguarding our environment for future generations.
Year Completed |
1955 |
Dam Length |
771 |
Dam Height |
27 |
River Or Stream |
TR-WHITE RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
27 |
Nid Storage |
43 |
Hazard Potential |
Low |
Nid Height |
27 |
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.
Thomas Number 1