Phosphoria P-5 Reservoir Report
Nearby: P-5 Phosphoria P-1
Last Updated: December 5, 2025
Phosphoria P-5, located in Polk County, Florida, is a privately owned tailings dam with a significant hazard potential.
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Summary
Constructed in 1992 by ARDAMAN & ASSOCIATES, this earth dam stands at 50 feet high and has a hydraulic height of 45 feet. With a storage capacity of 26,000 acre-feet, the dam serves the primary purpose of tailings storage for the mining industry.
Managed by the Florida Department of Environmental Protection (FDEP), Phosphoria P-5 is regulated, permitted, inspected, and enforced by the state. The dam, situated on the Alafia River, has a controlled spillway with a width of 64 feet. With a risk assessment indicating a very high risk level, the dam has not been rated for its condition assessment, and no emergency action plan (EAP) has been prepared.
Despite its age, Phosphoria P-5 remains a critical structure for managing mining waste in the region. However, its significant hazard potential underscores the importance of regular inspections, risk management measures, and the development of an EAP to ensure the safety of surrounding communities and the environment in the event of a potential failure.
Year Completed |
1992 |
Dam Length |
18900 |
Dam Height |
50 |
River Or Stream |
ALAFIA RIVER |
Primary Dam Type |
Earth |
Surface Area |
542 |
Hydraulic Height |
45 |
Drainage Area |
0.85 |
Nid Storage |
26000 |
Structural Height |
54 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
54 |
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.
Phosphoria P-5