Green Valley Reservoir Report
Nearby: May Dam May & Sons Dam
Last Updated: December 13, 2025
Green Valley, located in Jackson, South Dakota, is a private dam on the TR-White River with a low hazard potential.
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Summary
Built in 1940, this Earth type dam stands at 18 feet tall and spans 500 feet in length. It has a storage capacity of 100 acre-feet, with a maximum discharge rate of 5000 cubic feet per second. While the dam is not currently rated for condition assessment, it is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and undergoes regular inspections, permitting, and enforcement.
Despite its low hazard potential, Green Valley serves an important role in water resource management and flood control within the region. With a normal storage capacity of 30 acre-feet, the dam provides critical water storage and discharge capabilities for the surrounding area. The dam is situated within the St. Paul District of the US Army Corps of Engineers and falls under the jurisdiction of the state of South Dakota. While the dam's emergency action plan status and risk assessment measures are currently not available, its presence contributes to the overall water resource infrastructure in the region.
Green Valley dam, overseen by private owners, represents a vital piece of the water resource network in South Dakota. With its historical significance dating back to the 1940s, the dam plays a key role in maintaining water levels and controlling flood risks in the TR-White River watershed. While further data on condition assessments, emergency preparedness, and risk management are needed, the dam's regulated status and regular inspections ensure its continued operation for the benefit of the surrounding communities and the local ecosystem.
Year Completed |
1940 |
Dam Length |
500 |
Dam Height |
18 |
River Or Stream |
TR-WHITE RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
18 |
Nid Storage |
100 |
Hazard Potential |
Low |
Nid Height |
18 |
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.
Green Valley