M. Webb Reservoir Report
Nearby: R. Schrempp Clausen Dam
Last Updated: December 7, 2025
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Summary
Webb is a privately owned structure located in Dewey, South Dakota, along the TR-MOREAU river or stream. This earth dam, completed in 1946, stands at a height of 13 feet and has a length of 260 feet. It has a storage capacity of 50 acre-feet and a maximum discharge of 990 cubic feet per second. Despite being of low hazard potential, the dam's condition assessment is currently listed as "Not Rated".
Owned and regulated by the South Dakota Department of Environment and Natural Resources (DENR), M. Webb is subject to state permitting, inspection, and enforcement. The dam is within the jurisdiction of the state and is regularly monitored for compliance with safety standards. Although the structure has not been assessed for its emergency action plan (EAP) preparedness or risk management measures, it remains a key feature in the local water resource management system.
With its location in a rural area and limited associated structures, M. Webb serves as a vital component in the water infrastructure of Dewey, South Dakota. The dam plays a crucial role in managing water flow along the TR-MOREAU river or stream, providing essential storage capacity and flood control measures for the surrounding area. As interest in climate change adaptation and water resource management grows, M. Webb stands as a testament to the importance of maintaining and regulating critical infrastructure for the protection of communities and ecosystems.
Year Completed |
1946 |
Dam Length |
260 |
Dam Height |
13 |
River Or Stream |
TR-MOREAU |
Primary Dam Type |
Earth |
Hydraulic Height |
13 |
Nid Storage |
50 |
Hazard Potential |
Low |
Nid Height |
13 |
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