Aquifers are underground areas of rock, limestone, sandstone and soil that contain water. These large areas that are contained within layers underground in deep, intermediate and shallow zones contain billions of gallons of water that is pumped up and used for drinking water, irrigation for farms and other purposes. There is so much water in these underground aquifers that they are equal to almost one fifth of the water in the Great Lakes. The deepest aquifer is called the Floridian Aquifer and contains the largest amount of water. It underlies most of Florida and parts of Georgia and Alabama. The layer above it is called the Intermediate layer and is separate from the Floridian aquifer and the uppermost aquifer called the Surficial aquifer by a non-porous layer of rock and clay.
The aquifer where we pump and get most of our drinking water lies closest to the surface of the earth and is called the Surficial aquifer. It supplies about 90% of our drinking water. Aquifers get their water from rainfall that seeps into the ground and from areas called recharge zones where streams, rivers, marshes, swamps and other wetland areas allow flowing water to penetrate the ground and travel down to one or more of the aquifers. There are maps and illustrations on many websites showing the approximate size and depth of these aquifers. One of these websites is from the Univ. of Florida Water Quality report of Florida. You can click on an image and see what our aquifers look like. The South Florida Water Management District which controls the water supplies of much of South Florida also has an excellent website describing aquifers. I also like the Amy H. Remley Foundation website which gives wonderful illustrations of aquifers and much information about where our water comes from.