Sonnenschein Number 2 Reservoir Report
Last Updated: December 14, 2025
Sonnenschein Number 2 is a privately owned earth dam located in Fort Pierre, South Dakota, along Branch Willow Creek.
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Summary
Constructed in 1963 by the Natural Resources Conservation Service, this dam stands at a height of 42 feet and has a storage capacity of 75 acre-feet. With a maximum discharge of 806 cubic feet per second, the dam serves the primary purpose of water resource management in the area.
Managed by the South Dakota Department of Environment and Natural Resources, Sonnenschein Number 2 is regulated, permitted, inspected, and enforced to ensure its safety and functionality. With a significant hazard potential, the dam has not been rated for its condition, highlighting the need for ongoing monitoring and maintenance. Although it has not been modified in recent years, the dam plays a crucial role in flood control and water supply for the local community.
Given its strategic location in Stanley County, South Dakota, Sonnenschein Number 2 is a key infrastructure for mitigating the impacts of climate change on water resources in the region. With its capacity to store water and control flooding, the dam contributes to climate resilience efforts and underscores the importance of proper management and maintenance of water infrastructure in the face of a changing climate.
Year Completed |
1963 |
Dam Length |
480 |
Dam Height |
42 |
River Or Stream |
BRANCH WILLOW CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
42 |
Nid Storage |
75 |
Hazard Potential |
Significant |
Nid Height |
42 |
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.
Sonnenschein Number 2