Johnson Dam Reservoir Report
Nearby: Mud Creek Dt Dam M-1 Labolt Lake
Last Updated: December 13, 2025
Johnson Dam, located in Deuel County, South Dakota, is a privately-owned earthen dam that was completed in 1965.
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Summary
The dam stands at a height of 24 feet and has a storage capacity of 180 acre-feet, with a normal storage level of 50 acre-feet. Situated on a tributary of Mud Creek, Johnson Dam serves as a crucial water resource in the region, providing irrigation for agriculture and supporting local ecosystems.
Managed by the South Dakota Department of Environment and Natural Resources (DENR), Johnson Dam is regulated, permitted, inspected, and enforced by the state to ensure its safety and functionality. The dam has a low hazard potential and a moderate risk assessment, indicating that it is well-maintained and poses minimal threat to downstream areas. While the dam is currently in a not rated condition assessment status, regular inspections and risk management measures are in place to mitigate any potential issues and ensure the safety of the surrounding community.
With Dusty Johnson, a Republican representative, overseeing the congressional district where Johnson Dam is located, the dam plays a vital role in water resource management and climate resilience efforts in the area. As a key infrastructure for water supply and flood control, Johnson Dam exemplifies the importance of sustainable dam operations and the collaboration between state and federal agencies to safeguard water resources and mitigate environmental risks.
Year Completed |
1965 |
Dam Length |
250 |
Dam Height |
24 |
River Or Stream |
TRIB. MUD CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
24 |
Nid Storage |
180 |
Outlet Gates |
None |
Hazard Potential |
Low |
Nid Height |
24 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Yellow Bank River Near Odessa
|
100cfs |
Whetstone River Near Big Stone City
|
29300cfs |
Minnesota River At Ortonville
|
130cfs |
Big Sioux R At Watertown Sd
|
26cfs |
Big Sioux R Near Watertown Sd
|
19cfs |
Big Sioux R Near Castlewood Sd
|
68cfs |
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.
Johnson Dam