Coronet No. 4 is an earth dam located in Hillsborough, Florida, built in 1930. It carries a Significant hazard potential classification.
Dam profile
NID height · 10 ft10 ft tall and 8,000 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 Coronet No. 4
The primary purpose of Coronet No. 4 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 (english Creek) near Plant City.
The dam stands 10 feet tall and stretches 8,000 feet across, creates a reservoir covering 131 acres, has a maximum storage capacity of 1,100 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1930, the structure is well-established, with more than 75 years of service.
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. An emergency action plan is in place for this dam. The most recent inspection on record was 07/24/2003. That was over 23 years ago.
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Location
| State | Florida |
| County | Hillsborough |
| Nearest City | Plant City |
| River/Stream | Alafia River (english Creek) |
| Coordinates | 28.00290, -82.08600 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Height | 9 ft |
| Dam Length | 8,000 ft |
| Year Completed | 1930 (96 years old) |
Storage & Hydraulics
| NID Storage | 1,100 acre-ft |
| Max Storage | 1,100 acre-ft |
| Normal Storage | 900 acre-ft |
| Surface Area | 131 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 20 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Tailings |
| Owner | The Mosaic Company |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 07/24/2003 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | FL12002 |
| Federal ID | FL12002 |
| More Info | State Dam Safety Program |