Aquifers
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Aquifers are an essential source of water to creeks through springs and seeps. They also provide critical habitat for endangered and threatened species and supply drinking water for millions of Central Texas residents. The most well-known aquifer in the Austin area is the Edwards Aquifer, which is recharged when surface water flows across the weathered Edwards limestone and travels below ground through fractures.
The Barton Springs segment of the Edwards Aquifer is best known as the source of Barton Springs Pool and habitat for the endangered Barton Springs and Austin Blind salamanders. There are four springs located in the Zilker Park area that make up the most populated habitat of the Barton Springs salamander, which are together called the Barton Springs Complex. The springs include Main Barton (in the pool), Eliza, Old Mill (also known as Sunken Gardens), and Upper Barton Springs.
In North Austin, small springs discharging from the Northern Edwards Aquifer provide critical habitat for the threatened Jollyville Plateau salamander and help keep popular recreational creeks like Bull Creek flowing throughout the year. Because the Edwards Aquifer is a karst aquifer, meaning water flows through the weathered holes and fractures in the limestone rock rather than filtering down through particles like sand and silt, the aquifer and the creatures that call it home are more vulnerable to surface water contamination.
Some of these species can serve as an indicator of water quality for the springs and aquifer.
Barton Springs Salamander counts by year across the Barton Springs Complex. Surveys to monitor the population size of the Barton Springs salamander are conducted multiple times per year at each spring site. A line is displayed for each year showing the minimum and the maximum number of salamanders counted during a survey.
During surveys, biologists capture, photograph, and release the salamanders. The Barton Springs salamander has unique markings that allow us to track individuals over time as they are recaptured. From these data, we can estimate the population size and assess whether migration is occurring between the springs. Results of this work will provide new insights about ecosystem health and integrity in the Barton Springs segment of the Edwards Aquifer.
Scientists are still studying how and why salamander abundance varies over time. This is important to biologists because factors that influence population fluctuations have important consequences for the management and protection of this endangered species.
