What is the Edwards Aquifer and Why should we care?

Image courtesy of Edwards Aquifer Website

Water is essential to human life. We drink, we bathe, we water our lawns, we swim and play in water, we eat food that took a lot of water to produce, all without giving much thought to where that water came from and if it will be there tomorrow. But with our growing populations and changing climate the availability of water is becoming a critical issue in the public eye, especially in the more arid areas of United States. One of such relatively arid areas is South Central Texas, which receives an average of 26-34 inches of rainfall annually. The area, similarly to the rest of Texas, relies heavily on groundwater for its agriculture, municipal, industrial and other uses.
The Edwards Aquifer is located in South Central Texas and is an underground layer of porous, water-bearing limestone. It runs for some 160 miles from N.Austin, through San Antonio and West toward the Rio Grande. The water from the aquifer maintains the flow of many streams and rivers in the area that provide habitat to a variety of plant and animal life, some of which are threatened or endangered. It is essential to sustaining the local ecosystem.
One of such endangered species is the Barton Springs Salamander, Eurycea sosorum. This aquatic salamander inhabits the spring flows of Barton Springs in Austin, TX and was first described in 1993. By 1997 the species was listed as Endangered and major recovery programs were started by the City of Austin and Austin's Parks and Recreation Department. 

The Aquifer also provides water to 1.5-2 million people of South Central Texas. Most of the water pumped from the aquifer is used for municipal purposes. Municipal uses include residential, commercial (retail stores, office buildings and etc.) and institutional (schools, prisons and etc.). Total water distribution from the Aquifer looks something like this: 

Image courtesy of Edwards Aquifer Authority

The water reaches and "recharges" the aquifer from rain runoff in the Contributing Zone (see image above) that collects and percolates through the ground. In the Recharge Zone the Edwards limestone is exposed and so the water enters the aquifer through caves, sinkholes and cracks in the ground. Building and developing the land within the Recharge Zone limits the amount of water that can penetrate through the ground into the aquifer. 

It is possible to deplete the aquifer by pumping water out at a rate higher than its recharge rate. Overdrafting can lead to higher water costs, degradation of water quality and can have a negative impact on springs and steam flows. This becomes a critical issue at times of drought when the rate the recharge is well below normal. 

The state of Texas is separated into 16 Regional Water Planning Groups. Each of these groups consists of at least 11 members that represent various water interest or user - public, water counties, water utilities, river authorities, cities, industry, environmental, electric generating utilities, agriculture and etc. All of these groups together with Texas Water Development Board come up with the State Water Plan which directs state funding for water development. 

Groundwater in particular is managed through Groundwater Management Areas. There are also 16 of these areas in the state, but they are geographically different from the Regional Water Planning Areas. The Texas Water Development Board is in charge of approval of groundwater management plans. 

In recent years Texas has been plagued by major droughts, which are likely to continue and intensify with climate change. Similar to other areas in the Southwestern U.S. water availability and quality are becoming critical issues in the public eye in South Central Texas. Adding to the pressure is the fast growth and development of the city of Austin and its surrounding area. This year the city was first on Forbes' lists of America's Fastest-Growing Cities. More growth and development means more concrete - an impermeable material that will cover more and more of Edward Aquifer's recharge zone and prevent the return of water into the ground. More development means more industry and more cars and therefore more pollutants that will get washed down with the rain and into the public's water sources. 

A multitude of water conservation programs focusing on education and technological solutions started throughout South Central Texas in the last decade. But the effectiveness of these programs with growing demand for water and intensifying droughts remain to be seen.