Nelson Dam Reservoir Report
Last Updated: December 13, 2025
Nelson Dam, located in South Dakota along Cedar Creek, was completed in 1980 and stands at a height of 40 feet.
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Summary
This earth dam serves as a water resource for the area, providing a maximum storage capacity of 150 acre-feet. With a low hazard potential and a moderate risk assessment rating, the dam is not currently rated for its condition but is inspected, permitted, and regulated by the state agency DENR.
The dam features an uncontrolled spillway with a width of 75 feet and a maximum discharge capacity of 1560 cubic feet per second. Owned and operated by a private entity, Nelson Dam plays a crucial role in managing water flow and storage in the region. Despite its relatively low hazard potential, the dam's risk assessment suggests a moderate level of risk, highlighting the importance of continued monitoring and maintenance to ensure its safety and effectiveness in the face of changing climate conditions.
With its strategic location in Charles Mix County, South Dakota, Nelson Dam serves as a key infrastructure for water resource management in the area. As climate change continues to impact water availability and variability, the dam plays a vital role in mitigating risks and ensuring a reliable water supply for the local community.
Year Completed |
1980 |
Dam Length |
250 |
Dam Height |
40 |
River Or Stream |
TR. CEDAR CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
40 |
Nid Storage |
150 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
40 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Platte Creek Near Platte
|
3cfs |
Niobrara River At Mariaville
|
1530cfs |
White R Near Oacoma Sd
|
105cfs |
Firesteel Cr Near Mount Vernon Sd
|
0cfs |
Keya Paha R At Wewela Sd
|
54cfs |
Ponca Creek At Verdel
|
23cfs |
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.
Nelson Dam