Kingsford A-11 is an earth dam located in Polk County, Florida, built in 1977. It carries a Significant hazard potential classification.
Dam profile
NID height · 30 ft30 ft tall and 12,800 ft long, taller than 68% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Kingsford A-11
The primary purpose of Kingsford A-11 is tailings. Tailings dams contain waste material from mining operations — typically a slurry of finely ground rock left over after valuable minerals have been extracted. These structures require ongoing monitoring because tailings can contain heavy metals and other contaminants. The dam is owned by The Mosaic Company (private). It impounds the Alafia River near Keysville.
The dam stands 30 feet tall and stretches 12,800 feet across, creates a reservoir covering 277 acres, and has a maximum storage capacity of 8,300 acre-feet. Completed in 1977, the structure is 49 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life.
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Location
| State | Florida |
| County | Polk |
| Nearest City | Keysville |
| River/Stream | Alafia River |
| Coordinates | 27.84000, -82.02000 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 12,800 ft |
| Year Completed | 1977 (49 years old) |
Storage & Hydraulics
| NID Storage | 8,300 acre-ft |
| Max Storage | 8,300 acre-ft |
| Normal Storage | 5,000 acre-ft |
| Surface Area | 277 acres |
| Max Discharge | 290 cfs |
Ownership & Safety
| Purpose | Tailings |
| Owner | The Mosaic Company |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | No |
Identifiers
| NID ID | FL00664 |
| Federal ID | FL00664 |
| More Info | State Dam Safety Program |