Sully Dam Reservoir Report
Nearby: Blessing No.1 Irwin Dam
Last Updated: December 13, 2025
Sully Dam, located on the White River off stream in Tripp, South Dakota, is a state-regulated earth dam with a height of 17 feet and a length of 952 feet.
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Summary
Completed in 1935, the dam has a storage capacity of 1062 acre-feet, with a normal storage level of 420 acre-feet. The dam's primary purpose and specific purposes are not specified, but it serves as a crucial water resource structure in the region.
Managed by the St. Paul District of the US Army Corps of Engineers, Sully Dam has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. The dam undergoes inspections every three years, with the last inspection conducted in October 2017. Despite not having an Emergency Action Plan (EAP) prepared or updated, the dam's risk management measures and inundation maps are not specified. With its picturesque location and vital role in water resource management, Sully Dam stands as a testament to engineering ingenuity and environmental stewardship in South Dakota.
Year Completed |
1935 |
Dam Length |
952 |
Dam Height |
17 |
River Or Stream |
WHITE RIVER OFF STREAM |
Primary Dam Type |
Earth |
Hydraulic Height |
17 |
Nid Storage |
1062 |
Hazard Potential |
Low |
Nid Height |
17 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
White R Near Oacoma Sd
|
105cfs |
Keya Paha R At Wewela Sd
|
54cfs |
Platte Creek Near Platte
|
3cfs |
Keya Paha R Near Keyapaha Sd
|
33cfs |
Niobrara River At Mariaville
|
1530cfs |
Long Pine Creek Near Riverview
|
188cfs |
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.
Sully Dam