W. Mann No.3 Reservoir Report
Nearby: Blazek Dam Timmons Wetland Dam
Last Updated: December 6, 2025
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Summary
Mann No.3 is a private earth dam located on the TR CHEYENNE river in Meade, South Dakota. Completed in 1956, this dam stands at a height of 15 feet and has a storage capacity of 72 acre-feet, with a normal storage level of 44 acre-feet. The dam serves the primary purpose of water resource management and flood control, with a maximum discharge capacity of 2000 cubic feet per second.
Managed by the South Dakota Department of Environment and Natural Resources (DENR), W. Mann No.3 is regulated, inspected, and enforced by state authorities to ensure its structural integrity and operational safety. Despite being rated as having a low hazard potential and not having a current condition assessment, the dam continues to play a crucial role in water management in the region. With no emergency action plan or inundation maps prepared, there is room for improvement in disaster preparedness and risk management for this water resource infrastructure.
Overall, W. Mann No.3 represents a key component of the water infrastructure in Meade County, South Dakota, contributing to water supply stability and flood protection along the TR CHEYENNE river. As climate change continues to impact water resources, the maintenance and monitoring of dams like W. Mann No.3 will be essential in ensuring the resilience of water systems in the face of changing environmental conditions.
Year Completed |
1956 |
Dam Length |
550 |
Dam Height |
15 |
River Or Stream |
TR CHEYENNE |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Nid Storage |
72 |
Hazard Potential |
Low |
Nid Height |
15 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Cheyenne R Near Plainview Sd
|
0cfs |
Belle Fourche River Near Elm Springs
|
17900cfs |
Elk Cr Near Elm Springs Sd
|
0cfs |
Moreau R Near Faith Sd
|
14cfs |
Belle Fourche R Near Sturgis Sd
|
34cfs |
Cheyenne River Near Wasta
|
190cfs |
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.
W. Mann No.3