Seacoast is undertaking a project to diversify and increase its water supply resources by tapping into the brackish upper portion of Floridan aquifer system (Floridan). The aquifer is very large, it is present beneath the entire state of Florida and it has approximately a 1,000 feet thickness beneath the Hood Road water treatment plant. To develop water from the Floridan aquifer, Seacoast has contracted a state certified water well contractor to install the wells and professional hydrogeologists to design the wells which includes investigating the geology and water quality at each well site.

During drilling of the well, an experienced field geologist collects and examines drill cuttings and aquifer water samples as the bit penetrates deeper into the aquifer. Collecting this information during the drilling process is critical to determine the most ideal completion interval for the well. Construction of a well in the artesian Floridan aquifer is a complicated process that involves repeated stages of drilling, testing and casing installations. The work is accomplished using a rotary drilling rig which is clearly visible from to Hood Road at the northwest corner of the water treatment plant and will continue during the spring and early summer of 2009. The temporarily modified driveway and parking area at the Hood Road Administration Building is to accommodate the well drilling process.

Eastern Palm Beach County has two unique aquifer systems that are used for water supply: the surficial (fresh water) aquifer and the brackish Floridan aquifer system. The two aquifers are separated by a thick sequence of confining silt and clay called the intermediate confining unit. The surficial aquifer is the only fresh groundwater resource in southeast Florida and extends from the water table to a maximum depth of approximately 300-feet below land surface (BLS) in the vicinity of the Hood Road water treatment plant. In contrast, the Floridan is located underneath an approximately 700-feet thick intermediate confining unit, and begins at a depth of approximately 935-feet BLS. Throughout Palm Beach County and most of south Florida, the Floridan is under artesian pressure and water levels in completed wells can be more than 30-feet above land surface.

The surficial aquifer is composed of various geologic units consisting of unconsolidated layers of sand, shell, silt and clay, as well as limestone, and sandstone. The geologic units include the Pamlico Sand, Anastasia, Fort Thompson, and Tamiami. As stated previously, the aquifer is fresh water (not saline) and renewed by the plentiful rainfall we receive each year. The fresh water is made potable by the water treatment plant.

In contrast, the upper Floridan aquifer, is significantly deeper, approximately 935-feet below land surface at the Hood Road plant. The upper Floridan is predominantly composed of interbedded limestone and dolomite of Late Miocene to middle Eocene age, represented by four primary rock units. From approximately 935-feet BLS at the site, in descending order, these units are: Arcadia Formation of the Basal Hawthorne Unit (Miocene, 9.5 to 16 million years ago); the Suwannee Limestone (Oligocene, 23.3 to 35.4 million years ago); the Ocala Group (Eocene, 35.4 to 56.5 Million years ago); and the Avon Park Limestone (Eocene age, 35.4 to 56.5 Million years ago). The water producing zones within the upper Floridan can generally be referred to as "flow zones", which is typically a thin layer of highly porous rock where water can flow more rapidly. Hydrogeologic testing of drill cuttings and groundwater during the drilling process are used to identify these zones. Locally, the upper Floridan aquifer contains brackish water and is not locally recharged by rainfall like the surficial aquifer. It typically has TDS concentrations around 5,000 mg/L which is at least 10 times the TDS in drinking water. Although the water produced from the UFA is not fresh, it is very clear and is an excellent source of water for treatment by reverse osmosis filtration. .