Protecting the Edwards Aquifer
The Edwards Aquifer in Central Texas is the most economically productive aquifer in the state and—at the same time—the most ecologically vulnerable to outside elements. The TCEQ and other agencies keep a close eye on what is happening with this underground water resource.
Regulations and scrutiny focus on one of
the most productive aquifers in the U.S.
The Edwards Aquifer in Central Texas is the most economically productive aquifer in the state and—at the same time—the most ecologically vulnerable to outside elements. The TCEQ and other agencies regularly keep a close eye on what is happening with this underground water resource.
In this story:
State Oversight
Aquifer Governance
State-Federal Agreement
Database Debuts
Variables in Play
Sidebar: Online Map Access
Sidebar: Comprehensive Database
Of the groundwater supplies regulated by the TCEQ, one is an aquifer that receives extra protection, based on what is happening above it on land.
The Edwards Aquifer extends through many counties in Central Texas, serving as the primary source of drinking water for about 1.7 million people, including residents of San Antonio.
The Edwards is a karst aquifer, making it one of the most permeable and productive groundwater systems in the United States. The replenishable structure supplies water to meet the diverse needs and interests of the region, including farming and ranching, manufacturing, steam electric power generation, mining, households, and recreation.
Its pure spring water supports a unique ecosystem of aquatic life, including a number of threatened and endangered species. Scientists from around the country have studied its distinctive features.
The TCEQ has regulations protecting water quality in the Edwards Aquifer. Also, a special-purpose district-—the Edwards Aquifer Authority—regulates and manages aquifer pumpage, and spearheads water conservation efforts in eight counties from Uvalde to Hays.
The quality and quantity of water in the aquifer is a topic of frequent debate, especially as residential and commercial developments rapidly expand across its surface.
The last year has produced a number of important developments that could set the course for protecting and monitoring the aquifer for the coming decade. Among these are:
- The TCEQ received authority to increase the fees assessed for processing proposed aquifer-protection plans, and it expanded the staff that monitors regulated activities affecting the aquifer.
- The Legislature raised the ceiling on aquifer pumping capacity but also spelled out cutbacks during critically dry periods.
- The U.S. Fish and Wildlife Service and the TCEQ published an agreement on the voluntary use of new, enhanced measures to protect the water quality of the aquifer and the species living there.
- A new database was created to allow for more comprehensive monitoring of potential pollution in the aquifer.
State Oversight
Because of the unusual nature of the Edwards' geology and biology—and its role as the primary water source for many Texans—the aquifer receives enhanced protection and regulatory oversight.
Rainfall—as well as other surface runoff—enters the aquifer directly through fractures, caves, sinkholes, and other features within the recharge zone. Through these openings, water runs rapidly into the aquifer with little or no filtration to remove contaminants. After traveling underground, water can discharge through wells or natural springs, which feed surface springs and rivers.
Surface streams in the aquifer's contributing zone also provide recharge water.
That means that any activities onthe surface, or excavation below thesurface, have a direct bearing on the water and inhabitants belowground.
With a variety of aquatic speciesdepending on reliable levels of watermoving through the aquifer, the issueof diminished flows has been one ofconstant concern.
The TCEQ requires a water pollution abatement plan for any regulated activity proposed for the recharge or contributing zones. This includes construction of buildings, roads, and highways; clearing, excavation, or anything else that alters the surface; and any other activities that could contaminate the aquifer and its surface streams.
The agency also requires a geologic assessment of all new, regulated developments, except for residential sites smaller than 10 acres. Best management practices must be used during and after construction to treat storm water—creating, for example, silt fences, sand filtration basins, and retention ponds.
The TCEQ also has stricter regulations for aboveground and belowground storage tanks and on-site sewage facilities located in the recharge and contributing zones.
The Legislature in 2007 authorized higher fees for the review of water pollution abatement plans, which will take effect in May 2008. Rather than a current cap of $5,000, fees may go as high as $13,000, depending on the project size. The TCEQ received about 700 applications for review in fiscal 2007.
TCEQ engineers and geologists in the Austin and San Antonio regional offices review the plans and perform site assessments before any development occurs.
With the development boom between San Antonio and Austin, the number of investigators assigned to Edwards Aquifer activities in that area has increased from 10 to 17. The agency goal for staff review of each Edwards Aquifer protection plan has been shortened from 90 to 60 days. To maintain this expedited review schedule, the TCEQ requires that all plans be administratively complete before staff begins a thorough review of the technical requirements.
With the economic growth in the region has come a sharp increase in the number of significant enforcement violations. This led the TCEQ to hike the penalties levied for construction activities that begin before the agency grants authorization. Penalties can now be calculated by the day—up to $10,000 per violation.
Aquifer Governance
The Edwards Aquifer Authority was created by the Legislature in the 1990s with a board of directors charged with managing and preserving the aquifer recharge and its aquatic life. The agency manages a groundwater withdrawal permit program for agricultural, commercial, and municipal aquifer users that rely on the underground water supply.
The district has issued about 930 withdrawal permits in its jurisdiction, representing some 12,000 wells, according to Roland Ruiz, spokesman for the authority. The largest aquifer permit holder is the San Antonio Water System.
Recent legislation raised the annual pumping capacity to 572,000 square feet from 450,000 square feet to more accurately reflect the total sum of permits already issued for groundwater withdrawal. Also, pumping reductions during critical stages of drought were written into law.
In addition, legislation created a project to determine the spring flow rates necessary for the survival of endangered and threatened species. The TCEQ and other agencies will assist the authority in developing recommendations for withdrawal rates to maintain target spring discharge levels.
Ruiz said the authority's first decade of operations mostly focused on water supply. "But now that we've established the permit process to help manage quantity, we can turn more of our attention to water quality."
The authority already has programs in place, he said, that set standards for plugging old wells and ensuring that new ones are properly constructed to prevent pollution. The authority also prohibits fuel-storage tanks of certain sizes over the most environmentally sensitive area of the recharge zone.
The authority is considering rules that would regulate the storage of hazardous materials and petroleum products over the recharge and contributing zones of the aquifer, and require all spills to be reported within 72 hours.
State-Federal Agreement
After negotiating several years, the TCEQ and the U.S. Fish and Wildlife Service eliminated duplicate approval requirements for activities in the aquifer region.
The federal agency agreed that the voluntary use of new, enhanced measures in the TCEQ's Edwards Aquifer Protection Program can protect water quality and provide safeguards for species that are listed as endangered or threatened.
Applicants for permits to develop in the aquifer may choose optional enhanced measures to reduce the development's impact on water quality in the aquifer as well as upstream. The optional measures, including best management practices, also address stream-channel erosion resulting from increased impervious cover. Applicants can choose best management practices from the TCEQ's technical guidance materials.
The Fish and Wildlife Service agreed that applicants choosing to incorporate optional enhanced measures in their TCEQ-approved plans will not need to apply for separate approval under the federal endangered species program. This step is not a delegation of federal responsibilities to the TCEQ but an acknowledgment that TCEQ rules and guidance address known threats to endangered or threatened species that rely on the aquifer and its springs.
Database Debuts
In an agreement with the TCEQ, the U.S. Geological Survey (USGS) undertook a mighty endeavor to compile in one location the pertinent data from eight local, state, and federal agencies involved with the Edwards Aquifer.
After 18 months of reviewing and formatting the various data, the result is the Edwards Aquifer Water Quality and Biological Data Clearinghouse, containing an estimated 1.2 million water quality records and 38,000 biological records.
All this information was drawn from more than 4,000 monitoring sites within the regulatory boundaries of the TCEQ's Edwards Aquifer Protection Program. The data reflect the results of monitoring groundwater, spring water, and surface water for factors such as pH, temperature, dissolved oxygen, trace metals, pesticides, nutrients, and bacteria.
USGS is using the data to analyze water quality trends in the aquifer. A report is due to the TCEQ in August 2008.
Variables in Play
The quantity and quality of water in the Edwards Aquifer are constantly monitored as weather and human activity exert regular and sometimes unpredictable influences.
In 2006, an especially dry year for the region, aquifer levels and springflow rates fell so low that the Authority had to invoke mandatory pumping reductions. Then, plentiful rainfall in the first half of 2007 raised aquifer levels to 700 feet, just a few feet short of the record high. The abundant levels even restored the flows of usually dormant springs.
Meanwhile, gone are the days when the aquifer was relatively protected by undeveloped land in the recharge and contributing zones.
The area north of San Antonio, which overlaps some of the most sensitive ecological features of the region, is a hotbed of residential and commercial growth. This places more demands on the aquifer supplies and creates even more sources of potential pollution, such as urban storm water runoff.
Management and reliability of the Edwards Aquifer will continue to depend on development projects that are environmentally sensitive, and the application of regulations designed to ensure protection of the aquifer, consistent with sustainable economic development.
Online Map Access
In 2005, the TCEQ conducted a major project to update maps of the Edwards Aquifer. The result was revised boundaries of the aquifer regulatory zones in the counties of Bexar, Comal, Hays, and Travis.
The boundary lines and many other features of the region can be seen on the Edwards Aquifer Viewer on the TCEQ Web site.
With the zoom-in tool, users can go through various layers of detail, even finding cross streets and individual addresses. Another tool measures distances.
Comprehensive Database
The Edwards Aquifer Water
Quality and Biological Data Clearinghouse 
is a compilation of water quality data drawn from
the Texas Commission on Environmental Quality, U.S. Geological
Survey, city of Austin, Edwards Aquifer Authority, Guadalupe-Blanco
River Authority, Lower Colorado River Authority, San Antonio River
Authority, and Texas Water Development Board.
The data, including real-time monitoring readings updated every 15 minutes, are used to assess water quality trends in the aquifer and locate gaps in data coverage.
