Green Bay Gypstack Cell 1 is an earth dam located in Polk County, Florida, built in 1965. It carries a Significant hazard potential classification.
Dam profile
NID height · 85 ft85 ft tall and 11,000 ft long, taller than 97% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Green Bay Gypstack Cell 1
The primary purpose of Green Bay Gypstack Cell 1 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 Six Mile Creek near Mulberry.
The dam stands 85 feet tall and stretches 11,000 feet across, creates a reservoir covering 250 acres, has a maximum storage capacity of 2,072 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1965, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 09/07/2005. That was over 21 years ago.
At 85 feet, this dam is taller than 97% of all dams in the United States.
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Location
| State | Florida |
| County | Polk |
| Nearest City | Mulberry |
| River/Stream | Six Mile Creek |
| Coordinates | 27.84110, -81.92270 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 85 ft |
| Dam Height | 80 ft |
| Dam Length | 11,000 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 2,072 acre-ft |
| Max Storage | 2,072 acre-ft |
| Normal Storage | 1,500 acre-ft |
| Surface Area | 250 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 215 cfs |
Ownership & Safety
| Purpose | Tailings |
| Owner | The Mosaic Company |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 09/07/2005 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | FL00198 |
| Federal ID | FL00198 |
| More Info | State Dam Safety Program |