Cannon Dam Reservoir Report
Nearby: Velda Ramser Dam Archie Millard #2
Last Updated: December 13, 2025
Cannon Dam, located in Lyman, South Dakota, is a privately owned earth dam completed in 2009 on Mill Iron Creek.
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Summary
With a height of 13 feet and a storage capacity of 485 acre-feet, the dam serves as a vital water resource for the region. The dam has a low hazard potential and a moderate risk assessment rating, making it an important infrastructure for managing water flow and reducing the risk of flooding in the area.
Managed by the South Dakota Department of Environment and Natural Resources, Cannon Dam is regulated and inspected regularly to ensure its safety and effectiveness. The dam features an uncontrolled spillway with a width of 200 feet and has no outlet gates. While it is not currently rated for condition assessment, the dam's risk management measures are in place to mitigate any potential risks associated with its operation.
Water resource and climate enthusiasts can appreciate Cannon Dam for its role in water storage and flood control on Mill Iron Creek. With its strategic location and moderate risk assessment, the dam plays a crucial role in managing water resources in the region while minimizing the impact of potential hazards. As a privately owned structure, Cannon Dam showcases the importance of collaboration between private entities and regulatory agencies in maintaining and improving water infrastructure for the benefit of the community.
Year Completed |
2009 |
Dam Length |
1117 |
Dam Height |
13 |
River Or Stream |
MILL IRON CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
13 |
Drainage Area |
17 |
Nid Storage |
485 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
13 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
White R Near Oacoma Sd
|
105cfs |
White River Near White River
|
42cfs |
Little White R Below White River Sd
|
141cfs |
Bad R Near Fort Pierre Sd
|
7cfs |
Keya Paha R Near Keyapaha Sd
|
33cfs |
Keya Paha R At Wewela Sd
|
54cfs |
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.
Cannon Dam