Mandernach & Carlson No. 9 Reservoir Report
Nearby: G. Lund Mandernach And Carlson 3
Last Updated: December 6, 2025
Mandernach & Carlson No.
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Summary
9 is a privately owned dam located in Ziebach, South Dakota, along the TR CHEYENNE river. Constructed in 1949, this earth dam stands 23 feet tall and spans 475 feet in length, providing a storage capacity of 189 acre-feet. Managed by the Natural Resources Conservation Service, this dam is regulated by the South Dakota Department of Environment and Natural Resources, with state permitting and inspection processes in place to ensure its safety and compliance.
Despite its low hazard potential, Mandernach & Carlson No. 9 has not been rated for its condition assessment. Emergency action plans and risk assessments are currently unavailable, as are updated inundation maps and risk management measures. The dam's primary purpose and associated structures remain unspecified, highlighting the need for further evaluation and documentation of its operational and safety protocols. With a maximum discharge capacity of 1220 cubic feet per second, this dam plays a crucial role in water resource management in the region.
As water resource and climate enthusiasts continue to monitor and advocate for sustainable management practices, the case of Mandernach & Carlson No. 9 serves as a reminder of the importance of comprehensive dam safety assessments and emergency preparedness measures. While the dam's operational history and purpose remain unclear, its presence along the TR CHEYENNE river underscores the significance of proper regulatory oversight and maintenance protocols to safeguard against potential risks and ensure the long-term resilience of water infrastructure in South Dakota.
Year Completed |
1949 |
Dam Length |
475 |
Dam Height |
23 |
River Or Stream |
TR CHEYENNE |
Primary Dam Type |
Earth |
Hydraulic Height |
23 |
Nid Storage |
189 |
Hazard Potential |
Low |
Nid Height |
23 |
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.
Mandernach & Carlson No. 9