Hydrology of the sand-and-gravel aquifer, southern Okaloosa and Walton Counties, northwest Florida

The sand-and-gravel aquifer in southern Okaloosa and Walton Counties, northwest Florida, extends from land surface to depth of 50 to 150 feet. Intervening layers of clay generally separate the aquifer into an unconfined surficial zone, composed principally of fine to medium sand, and a lower confined zone, consisting of variable amounts of medium to coarse sand and gravel. Well yields of 50 to 500 gallons per minute are possible in most of the area, and yields of 500 to 1,000 gallons per minute can be developed in parts of southwestern Okaloosa County.