Anderson No.1 Reservoir Report
Nearby: Ecklund No. 2 Eklund #3
Last Updated: December 13, 2025
Anderson No.1 is a privately owned dam located in Mellette, South Dakota, on the Oak Creek Offstream.
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Summary
Built in 1966, this earth dam stands at 22 feet high and stretches 510 feet in length, with a storage capacity of 59 acre-feet. Despite being regulated by the South Dakota Department of Environment and Natural Resources, the dam's hazard potential is classified as low, with a condition assessment that is currently not rated.
The dam's primary purpose and associated structures are not specified, but it is equipped with outlet gates and has a maximum discharge capacity of 789 cubic feet per second. The dam is not under the jurisdiction of any federal agency, with no federal fundings, designers, constructions, or inspections associated with it. While the dam's Emergency Action Plan status and risk assessment information are unclear, it is reassuring to note that Anderson No.1 meets state regulatory standards and is inspected, permitted, and enforced by the appropriate authorities on a regular basis.
For water resource and climate enthusiasts, Anderson No.1 provides an interesting case study in private dam ownership and state regulation. Its location in South Dakota, with a low hazard potential and a history dating back to the mid-20th century, offers insights into the management and maintenance of smaller-scale dams in the United States. The dam's ungraded condition assessment indicates a need for further evaluation and potential improvements, highlighting the ongoing importance of monitoring and ensuring the safety of critical infrastructure for water resource management in the face of changing climate conditions.
Year Completed |
1966 |
Dam Length |
510 |
Dam Height |
22 |
River Or Stream |
OAK CREEK OFFSTREAM |
Primary Dam Type |
Earth |
Hydraulic Height |
22 |
Nid Storage |
59 |
Hazard Potential |
Low |
Nid Height |
22 |
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.
Anderson No.1