Settling Area No 3 is an earth dam located in Polk County, Florida, built in 1971. It carries a Significant hazard potential classification.
Dam profile
NID height · 16 ft16 ft tall and 660 ft long. 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 Settling Area No 3
The primary purpose of Settling Area No 3 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 North Prong Alafia River near Mulberry.
The dam stands 16 feet tall and stretches 660 feet across, creates a reservoir covering 3 acres, and has a maximum storage capacity of 51 acre-feet. Completed in 1971, the structure is well into its service life at over 50 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 | Mulberry |
| River/Stream | North Prong Alafia River |
| Coordinates | 27.85000, -81.95000 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 16 ft |
| Dam Height | 16 ft |
| Dam Length | 660 ft |
| Year Completed | 1971 (55 years old) |
Storage & Hydraulics
| NID Storage | 51 acre-ft |
| Max Storage | 51 acre-ft |
| Normal Storage | 51 acre-ft |
| Surface Area | 3 acres |
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 | FL00625 |
| Federal ID | FL00625 |
| More Info | State Dam Safety Program |