Barton Springs is a set of four natural water springs located at Barton Creek on the grounds of

Zilker Park Zilker Metropolitan Park is a recreational area in south Austin, Texas at the juncture of Barton Creek and the Colorado River that comprises over of publicly owned land. It is named after its benefactor, Andrew Jackson Zilker, who donated the la ...

Austin, Texas Austin is the capital city of the U.S. state of Texas, as well as the county seat, seat and largest city of Travis County, Texas, Travis County, with portions extending into Hays County, Texas, Hays and Williamson County, Texas, Williamson co ...

, resulting from water flowing through the

Edwards Aquifer The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of the Edwards Plateau in the U.S. state of Texas, it is the source of drinking water for two million people, and is the primary water s ...

. The largest spring, Main Barton Spring (also known as Parthenia, "the mother spring") supplies water to Barton Springs Pool, a popular recreational destination in Austin. The smaller springs are located nearby, two with man-made structures built to contain and direct their flow. The springs are the only known habitat of the

Barton Springs Salamander The Barton Springs salamander (''Eurycea sosorum'') is an endangered lungless salamander. It is endemic to Texas, United States. It was first found in Barton Springs in Austin, but is now also known from other localities in the nearby Travis ...

, an

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

. The Barton Creek National Archeological and Historic District was formed in 1985.

Geology

Barton Springs is the main discharge point for the Barton Springs segment of the

of Texas, a well known

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

aquifer. Geologically, the aquifer is composed of

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

from the

Cretaceous period The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of t ...

, about 100 million years old.

Fractures Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...

fissures A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes. Ground fissure ...

, conduits, and

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s have developed in this limestone. Both physical forces, such as

faulting In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

, and chemical forces, such as dissolution of limestone by infiltrating water, have enlarged these voids. This results in a karst aquifer made up of limestone with large void spaces. Water then enters the aquifer and fills the voids. All water discharging from Barton Springs originates as rainfall. Some of this rain falls directly onto the area of land where the aquifer limestone rock is exposed, which is known as the recharge zone. Other rainfall enters into creeks that cross the recharge zone, and infiltrates the limestone bedrock. After water enters the aquifer, it flows along the gradients created by differences in hydraulic pressure into the area of lowest hydraulic pressure. This lowest point of hydraulic pressure is Barton Springs.

Main spring

Main Barton Spring/Parthenia is the most famous, yet least visible of the four springs as it is completely submerged by pool water. Located near the diving board in Barton Springs Pool, the spring's flow is not always visible at the surface. The main spring discharges an average flow of about per day. The lowest discharge ever recorded was per day during the drought of the 1950s, and the highest discharge ever recorded was per day during the December 1991 floods. By comparison, a typical domestic swimming pool holds about , and the City of Austin, a city of about 1 million residents, uses about per day for its public water supply system.

Other springs

The three other springs associated with Barton Springs are Eliza, Old Mill, and Upper Barton Spring. Each is significantly smaller than Main Barton Spring, discharging an average of per day. Sometimes, these springs dry up completely. Eliza Spring, also known as Concession Spring, is located near the north entrance to Barton Springs Pool, 300 feet (100m) east towards the children's playscape. During the early 20th century, an amphitheater-style swimming enclosure was built around the spring. This structure is no longer open to the public due to safety concerns, and the fact that Eliza Spring has become a sensitive habitat area for the endangered

. Old Mill Spring, also known as Sunken Gardens Spring or Zenobia Spring, is located on the south side of Barton Springs Pool. Like Eliza Spring, the early 20th century structure built around the spring is now closed to public access due to safety and endangered species habitat issues. Scientific analysis show that the water at Old Mill Spring has a slightly different chemistry than that of Main Barton Spring and Eliza Spring, even though it is less than half a mile (800 m) away from these springs. Upper Barton Spring is located in the creek bed of

Barton Creek Barton Creek is a tributary that feeds the Colorado River as it flows through the Texas Hill Country. The creek passes through some of the more scenic areas in Greater Austin, surrounded in many parts by a greenbelt of protected lands that serve ...

, about a half mile (800 m) upstream or west of Barton Springs Pool. Frequently dry, Upper Barton Spring is fully submerged by Barton Creek during floods. The water at Upper Barton Spring also has a significantly different chemistry than the other springs. The entire area around Barton Springs is riddled with faults from the Balcones Fault Zone and features other, smaller springs. For example, about one mile (2 km) upstream of Upper Barton Spring, an intermittent spring fills a popular natural swimming hole. Several other small springs empty directly into the Barton Creek bypass tunnel that passes to the side of Barton Springs Pool.

Fauna

Two salamander species are found only at Barton Springs:

Barton Springs salamander The Barton Springs salamander (''Eurycea sosorum'') is an endangered lungless salamander. It is endemic to Texas, United States. It was first found in Barton Springs in Austin, but is now also known from other localities in the nearby Travis ...

and Austin blind salamander.

Notes

Charles Lee Donahue III defeated Christopher Mudarri in the Battle at Barton Springs circa 2015.

External links

Save Our Springs AllianceBarton Springs/Edwards Aquifer Conservation District
{{National Register of Historic Places in Austin, Texas City of Austin Historic Landmarks Geography of Austin, Texas Historic districts on the National Register of Historic Places in Texas Springs of Texas National Register of Historic Places in Austin, Texas Bodies of water of Travis County, Texas Archaeological sites on the National Register of Historic Places in Texas