Anderson Dam Reservoir Report

Last Updated: December 13, 2025

Anderson Dam, located in Lyman, South Dakota, is a privately owned earth dam with a height of 21 feet and a storage capacity of 288 acre-feet.


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Summary

Situated on TR. MEDICINE CREEK, this dam serves as a vital water resource for the surrounding area, with a maximum discharge of 1350 cubic feet per second and a spillway width of 100 feet. Despite being classified as having a low hazard potential, the dam is subject to state regulation, inspection, and enforcement by the South Dakota Department of Environment and Natural Resources.

While the dam's condition assessment is currently listed as "Not Rated," its risk assessment is moderate, indicating a potential for some level of risk. The dam does not have an Emergency Action Plan (EAP) in place, suggesting a need for preparedness in the event of an emergency or disaster. With Dusty Johnson (R) representing the area in Congress, there is a connection to federal oversight, although the dam itself is not owned or funded by any federal agency.

Overall, Anderson Dam plays a crucial role in water management and flood control in the region, highlighting the importance of maintaining and monitoring its structural integrity. As climate change continues to impact weather patterns and water resources, the resilience and safety of dams like Anderson become increasingly significant in ensuring the well-being of communities and ecosystems downstream.

Dam Height

21

River Or Stream

TR. MEDICINE CREEK

Primary Dam Type

Earth

Hydraulic Height

21

Drainage Area

3

Nid Storage

288

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

21
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.