F3a Four Corners Mine Reservoir Report
Nearby: Mosaic Csa F2c Mosaic Csa Fc2c
Last Updated: December 5, 2025
The F3a Four Corners Mine in Florida is a private tailings dam located in Manatee County, near the Myakka River.
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Summary
Constructed in 2001 by ARDAMAN & ASSOCIATES, this earth dam stands at a height of 65 feet with a hydraulic height of 60 feet, serving primarily for tailings storage. With a storage capacity of 37,500 acre-feet and a surface area of 571 acres, the dam presents a significant hazard potential, rated as very high risk.
Despite being regulated and inspected by the Florida Department of Environmental Protection, the dam's condition assessment remains unrated as of the last inspection in 2006. The dam features a controlled spillway type with a width of 125 feet and a maximum discharge capacity of 80 cfs. The risk associated with this dam is further highlighted by its very high risk rating, emphasizing the importance of ongoing risk management measures to ensure the safety of the surrounding community and the environment. For water resource and climate enthusiasts, the F3a Four Corners Mine presents a case study of the critical importance of proper monitoring and maintenance of dam infrastructure to prevent potential disasters.
Year Completed |
2001 |
Dam Length |
19866 |
Dam Height |
65 |
River Or Stream |
MYAKKA RIVER |
Primary Dam Type |
Earth |
Surface Area |
571 |
Hydraulic Height |
60 |
Drainage Area |
0.89 |
Nid Storage |
37500 |
Structural Height |
68 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
68 |
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.
F3a Four Corners Mine