Barton Springs
Encyclopedia
Barton Springs is a set of four natural water springs located on the grounds of Zilker Park
in Austin, Texas
resulting from water flowing through the Edwards Aquifer
. 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
, an endangered species
.
The Barton Creek National Archeological and Historic District was formed in 1985.
of Texas, a well known karst
aquifer. Geologically, the aquifer is composed of limestone
from the Cretaceous period, about 100 million years old. Fractures, fissures, conduits
, and caves have developed in this limestone. Both physical forces, such as faulting, 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.
, the spring's flow is not always visible at the surface.
The main spring discharges an average flow of about 31 million USgals (117,347.8 m³) per day. The lowest discharge ever recorded was 9 million USgals (34,068.7 m³) per day during the drought of the 1950s, and the highest discharge ever recorded was 85 million USgals (321,760 m³) per day during the December 1991 floods. By comparison, a typical domestic swimming pool holds about 50000 gallons (189.3 m³), and the City of Austin, a city of about 775,000 residents, uses about 220 million USgals (832,790.6 m³) per day for its public water supply system.
Eliza Spring, also known as Concession Spring, is located on the northwestern side of Barton Springs Pool behind the concession stand. 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 Barton Springs Salamander
.
Old Mill Spring, also known as Sunken Gardens Spring or Zenobia Spring, is located on the northeastern 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
, about a half mile (800 m) upstream 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.
Zilker Park
Zilker Metropolitan Park is a recreational area in the heart of south Austin that comprises over of publicly owned land. It is named after its benefactor Andrew Jackson Zilker, who donated the land to the city in 1917. It was developed into the park during the Great Depression in the 1930s...
in Austin, Texas
Austin, Texas
Austin is the capital city of the U.S. state of :Texas and the seat of Travis County. Located in Central Texas on the eastern edge of the American Southwest, it is the fourth-largest city in Texas and the 14th most populous city in the United States. It was the third-fastest-growing large city in...
resulting from water flowing through the Edwards Aquifer
Edwards Aquifer
The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of Edwards Plateau in the U.S. state of Texas, it discharges about of water a year and directly serves about two million people...
. The largest spring, Main Barton Spring (also known as Parthenia, "the mother spring") supplies water to Barton Springs Pool
Barton Springs Pool
Barton Springs Pool is a man-made recreational swimming pool located on the grounds of Zilker Park in Austin, Texas. The pool exists in the channel of Barton Creek and is filled by water from Main Barton Spring, the fourth largest spring in Texas...
, 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
Barton Springs Salamander
The Barton Springs salamander is an endangered lungless salamander that only lives in the habitat of Barton Springs in Austin, Texas, USA...
, an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
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 Edwards AquiferEdwards Aquifer
The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of Edwards Plateau in the U.S. state of Texas, it discharges about of water a year and directly serves about two million people...
of Texas, a well known karst
Karst topography
Karst topography is a geologic formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite, but has also been documented for weathering resistant rocks like quartzite given the right conditions.Due to subterranean drainage, there...
aquifer. Geologically, the aquifer is composed of limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
from the Cretaceous period, about 100 million years old. Fractures, fissures, conduits
Channel (geography)
In physical geography, a channel is the physical confine of a river, slough or ocean strait consisting of a bed and banks.A channel is also the natural or human-made deeper course through a reef, sand bar, bay, or any shallow body of water...
, and caves have developed in this limestone. Both physical forces, such as faulting, 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 PoolBarton Springs Pool
Barton Springs Pool is a man-made recreational swimming pool located on the grounds of Zilker Park in Austin, Texas. The pool exists in the channel of Barton Creek and is filled by water from Main Barton Spring, the fourth largest spring in Texas...
, the spring's flow is not always visible at the surface.
The main spring discharges an average flow of about 31 million USgals (117,347.8 m³) per day. The lowest discharge ever recorded was 9 million USgals (34,068.7 m³) per day during the drought of the 1950s, and the highest discharge ever recorded was 85 million USgals (321,760 m³) per day during the December 1991 floods. By comparison, a typical domestic swimming pool holds about 50000 gallons (189.3 m³), and the City of Austin, a city of about 775,000 residents, uses about 220 million USgals (832,790.6 m³) 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 3 million USgals (11,356.2 m³) per day. Sometimes, these springs dry up completely.Eliza Spring, also known as Concession Spring, is located on the northwestern side of Barton Springs Pool behind the concession stand. 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 Barton Springs Salamander
Barton Springs Salamander
The Barton Springs salamander is an endangered lungless salamander that only lives in the habitat of Barton Springs in Austin, Texas, USA...
.
Old Mill Spring, also known as Sunken Gardens Spring or Zenobia Spring, is located on the northeastern 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
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 and forms a greenbelt that is the habitat for many indigenous species of flora and fauna, including at least seven...
, about a half mile (800 m) upstream 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
Balcones Fault
The Balcones Fault Zone is a tensional structural system in Texas that runs approximately from the southwest part of the state near Del Rio to the north central region near Waco along Interstate 35. The Balcones Fault zone is made up of many smaller features, including normal faults, grabens, and...
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.