Arbuckle-Simpson Aquifer

Vendome Well. A flowing artesian well in the Chickasaw National Recreation Area. A water sample from Vendome Well was determined to be 9,000 years old by carbon-14 dating. (Photo by Scott Christenson)

Turner Falls. The largest waterfall in Oklahoma. Springs discharging from the Arbuckle-Simpson aquifer into Honey Creek are the source of water to Turner Falls. (Photo by Noel Osborn, Ok. Water Resources Board)

Antelope Spring. Located in Chickasaw National Recreation Area. (Photo by Scott Christenson)

Buffalo Spring. Located in Chickasaw National Recreation Area. (Photo by Scott Christenson)

Byrds Mill Spring. USGS Hydrologist Scott Christenson collects a water sample from Oklahoma’s largest spring. (Photo by Noel Osborn, Ok. Water Resources Board)

The Arbuckle-Simpson aquifer, which underlies more than 500 square miles in south central Oklahoma, is the principal water source for approximately 39,000 people in the cities of Ada, Sulphur, and others in the region. The aquifer is also the source of a number of important springs in the region, including Byrds Mill Spring, Ada’s primary drinking water source, and those in the Chickasaw National Recreation Area, the destination for about 3.4 million visitors each year. The U.S. Environmental Protection Agency has designated the aquifer’s eastern portion as a Sole Source Aquifer, a mechanism to protect drinking water supplies in areas with limited water supply alternatives.

The Arbuckle-Simpson aquifer consists of limestone, dolomite, and sandstone within the Simpson and the Arbuckle Groups of Ordovician and Cambrian age and can be up to 9,000 feet thick. Rocks of the Arbuckle and Simpson Groups are exposed at the land surface in three uplifts, separated from each other by large high-angle faults. Intensive folding and faulting of a thick sequence of Paleozoic rocks formed the ancestral Arbuckle Mountains. Originally rising several thousand feet above the surrounding plains, the mountains have been eroded to their present-day maximum relief of about 600 feet.

Water is discharged naturally from the aquifer by numerous springs and seeps; much of this discharge becomes the base flow of streams. Springs that issue from the aquifer discharge up to 19,000 gallons per minute. Small karst features can be seen over much of the outcrop area of the aquifer, but human-enterable air-filled caves are found only in a few locations. Some of the springs and caves include unique fauna, including the Oklahoma cave amphipod, an invertebrate known from only four caves, all of which are located in the Arbuckle-Simpson aquifer.