M. Webb Reservoir Report
Nearby: Clausen Dam L. Koch
Last Updated: December 8, 2025
Located in Dewey, South Dakota, M.
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Summary
Webb is a privately owned dam that serves as a crucial water resource in the region. Built in 1947, this earth-type dam stands at a height of 16 feet with a length of 690 feet, providing a storage capacity of 300 acre-feet. With a maximum discharge of 4200 cubic feet per second, M. Webb plays a vital role in managing the flow of the TR-MOREAU river.
Managed by the South Dakota Department of Environment and Natural Resources (DENR), M. Webb is regulated, permitted, inspected, and enforced by the state authorities to ensure its safe operation. Despite being categorized as low hazard potential, the dam's condition assessment is currently not rated, highlighting the need for further evaluation and maintenance. Emergency action plans and risk management measures for the dam are yet to be fully developed and implemented, underscoring the importance of proactive measures to mitigate potential risks.
With a primary purpose that is not specified, M. Webb stands as a testament to the intersection of water resource management and climate resilience. As climate change continues to impact water availability and quality, the role of structures like M. Webb in ensuring sustainable water management practices becomes increasingly crucial. As enthusiasts in water resources and climate, understanding the significance of dams like M. Webb in the broader context of environmental stewardship and adaptation efforts is essential for promoting a resilient and sustainable future.
Year Completed |
1947 |
Dam Length |
690 |
Dam Height |
16 |
River Or Stream |
TR-MOREAU |
Primary Dam Type |
Earth |
Hydraulic Height |
16 |
Nid Storage |
300 |
Hazard Potential |
Low |
Nid Height |
16 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Moreau R Near Whitehorse Sd
|
35cfs |
Moreau R Near Faith Sd
|
14cfs |
Grand R At Little Eagle Sd
|
47cfs |
Cheyenne R Near Plainview Sd
|
0cfs |
Oak Cr Near Wakpala Sd
|
10cfs |
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.
M. Webb