September 30, 2016 Report
Global English [ Change Region ]

September 30, 2016 Report

 
September 30, 2016   |   ShareThis

Central Florida Geology Fact Sheet

The State of Florida has unique subsurface geology, with much of the underground rock layers made up of limestone, a highly porous rock. The Floridan Aquifer flows through these limestone layers and is known to be one of the most productive aquifers in the world. Due to the porous nature of these limestone layers, deep cavities have naturally formed over time in the rock layers below the surface. Sometimes, the surface layer of rock comprising the upper Floridan Aquifer above those underground cavities contain imperfections like small vertical gaps. Over many years, the surface layer can slowly erode downward, resulting in the formation of a sinkhole. Although scientists cannot accurately predict precisely where and when a sinkhole may occur, they do know that sinkholes are naturally occurring geological phenomena throughout much of Florida, where thousands of sinkholes are found.

Once the sinkhole at the New Wales site developed, Mosaic began evaluations to learn as much as possible about it. Because there was a water loss event associated with this sinkhole, Mosaic’s experts, third-party scientists and engineers have been closely studying what effects the sinkhole, and water lost to the sinkhole, could have on the underlying Floridan aquifer.

Through extensive well monitoring that collects data from 79 monitor wells tapping the shallow, intermediate and Floridan aquifers beneath the facility, as well as site-specific modeling of the direction and speed of water movement within the aquifer, hydrogeologists have accurately determined groundwater flow directions and movement characteristics in the particular part of the aquifer directly underneath the New Wales site.

In this part of the Floridan Aquifer, groundwater flows slowly in a westward direction. In general, the speed of water movement in an aquifer depends on many factors. In this case, it has been determined that, even without any influence from operating Mosaic’s recovery well, this part of the aquifer moves at only about 500 feet per month. This means that without any pumping, it would take more than 2 years for the water to move just to the western edge of the New Wales property boundary. However, Mosaic is taking action, by drawing the water from the affected portion of the aquifer directly up to the surface through a recovery well. This well acts essentially like a straw in the aquifer, recovering all of the slow-moving impacted water back up to the surface.

To keep additional water from entering the aquifer, the company will plug the sinkhole. Mosaic has retained a geotechnical firm that has extensive experience in remediating sinkholes. Remediation is expected to include a process of injecting a concrete mixture into the neck of the sinkhole to fill the cavity and stabilize the formation.

It is important to note that, as gypsum on surface layers surrounding the sinkhole’s opening begins to dry out over the next few weeks, it will shrink and some localized cracking and breaking around the hole can be expected. As this occurs, it may appear that the sinkhole is enlarging – though the underlying cavity remains the same size.

To further ensure the integrity of drinking water wells in the communities around the New Wales facility, the company is relying on elements of its extensive network of monitoring wells surrounding the facility that have been both reviewed and approved by regulators. The company is adding several more monitoring wells, to confirm that, as expected and as verified by models, the lost water is not moving past the recovery well.

Mosaic will continue to monitor the water for as long as it takes to demonstrate that all water lost to the aquifer has been safely recovered and that there are no impacts beyond our property boundaries.

Daily Well Testing Update

As of today, Mosaic has received 760 well water test requests. Environmental Consulting & Technology, Inc. (ECT) is prioritizing testing based on neighbor’s proximity to the New Wales facility. Neighbors who have requested an alternative means of testing are encouraged to receive a water test at no cost from the Florida Department of Environmental Protection (FDEP).

Testing and Bottled Water Requests as of September 30, 2016

As of 12:00 pm

Scheduled 3rd party well tests 760
Site visits/samples taken 275
Expected site visits today* 36
Requests for bottled water 478

*Plans could change based on residents’ availability or inclement weather.

Please note: Well testing updates for this weekend will be posted on Monday, October 3, 2016.