Canby R-4a Reservoir Report
Nearby: Canby R-1 Norman Twp 7
Last Updated: December 13, 2025
Canby R-4a, located in Yellow Medicine, Minnesota, is a vital flood risk reduction structure designed by the USDA NRCS and regulated by the MNDNR EWR.
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Summary
Completed in 1982, this earth dam stands at a height of 41 feet and has a length of 1200 feet, providing storage of 770 acre-feet and serving a drainage area of 2.4 square miles. The dam's primary purpose is flood risk reduction, with a spillway type designated as 'Uncontrolled' and a hazard potential rated as 'High'.
With a satisfactory condition assessment as of March 2017, Canby R-4a is regularly inspected to ensure its structural integrity. The dam's risk assessment is classified as moderate, indicating a potential for adverse impacts if not properly managed. While the dam has no outlet gates, its primary design and construction were overseen by the Natural Resources Conservation Service, emphasizing the importance of effective water resource management and climate resilience in the region. Canby R-4a serves as a critical infrastructure for mitigating flood risks and protecting the surrounding community from potential water-related hazards.
Year Completed |
1982 |
Dam Length |
1200 |
Dam Height |
41 |
River Or Stream |
COUNTY DITCH 19-TR |
Primary Dam Type |
Earth |
Surface Area |
5 |
Drainage Area |
2.4 |
Nid Storage |
770 |
Structural Height |
46 |
Outlet Gates |
None |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
46 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Lac Qui Parle River Near Lac Qui Parle
|
536cfs |
Redwood River Near Marshall
|
0cfs |
Minnesota River Near Lac Qui Parle
|
1240cfs |
Minnesota River At Montevideo
|
1810cfs |
Big Sioux River Near Bruce
|
280cfs |
Chippewa River Near Watson
|
423cfs |
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.
Canby R-4a