Cottonwood Lake Reservoir Report
Nearby: Timm Lake Curtis Lake East Bay
Last Updated: December 13, 2025
Cottonwood Lake, located in Lyon County, Minnesota, is a privately owned reservoir that serves various purposes, including recreation and water storage.
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Summary
The dam, completed in 1960, is a gravity type with a height of 9 feet and a storage capacity of 3,582 acre-feet. With a surface area of 378 acres and a drainage area of 20.5 square miles, Cottonwood Lake plays a vital role in managing water resources in the region.
The dam is regulated and inspected by the Minnesota Department of Natural Resources, ensuring its safety and functionality. Despite being classified as having a low hazard potential, the dam is in satisfactory condition, as assessed in 2010. The last inspection in November 2018 confirmed its structural integrity, and emergency preparedness measures are in place to mitigate any potential risks. With its location on the Yellow Medicine River and its contribution to water storage and management, Cottonwood Lake is a significant resource for the local community and environmental enthusiasts.
Overall, Cottonwood Lake stands as a testament to effective water resource management in Minnesota, providing recreational opportunities while ensuring the safety and sustainability of the surrounding ecosystem. Its role in regulating water flow and storage in the region, along with its low hazard potential and satisfactory condition, highlights the importance of maintaining and monitoring such infrastructure to mitigate potential risks and ensure the long-term health of our water resources and climate.
Year Completed |
1960 |
Dam Height |
9 |
River Or Stream |
YELLOW MEDICINE RIVER-TR |
Primary Dam Type |
Gravity |
Surface Area |
378 |
Drainage Area |
20.5 |
Nid Storage |
3582 |
Structural Height |
9 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
9 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Cottonwood Lake