That is a blessing and a curse but manageable..3 feet deep (high water table)
Like most of Florida there is high water table. Meaning you don't have to dig very deep to find water. Not this is q Huge benefit to a hot climate its air-conditioning from below. The water down 3 or 4 feet will be very much cooler then the air temp so don't build the pond up if you find water . You will however need to provide an escape for the water to get out from under the liner. They do sell perforated pipe like 1" that is secured side by side with a couple other pipe this gives the water a escape from under the liner andprevent the hippo. Those pipes need to come up to the surface and preferable piped or allowed to run away from the pond.