By Margarette Chavez
Wilson County News


The San Antonio Water System, better known as SAWS, is using $215 million of new technology to solve an age-old problem for arid South Texas.

It is employing an Aquifer Storage and Recovery (ASR) process that will allow it to store large quantities of drinking water in the Carrizo Aquifer for use during dry weather or peak periods of usage.

Once construction of the ASR is completed in January 2004, San Antonians will have water-rich insurance for protection in a worst-case scenario. The Edwards Aquifer will remain the primary source of San Antonio’s water supply, but SAWS sees a need to hedge its bet and diversify its water resources

SAWS anticipates the ASR project, with its 30 miles of 60- inch pipeline, will be storing 11,250 acre-feet of water by 2003, and 22,500 acre-feet of water by 2005.

According to Water Resources Communications Specialist Mario Aguilar, Bexar County has been in critically dry conditions only 17 times in the last 70 years; however, SAWS wants to prepare for that eventuality.

The project calls for water to be drawn from the Edwards Aquifer and injected into the Carrizo through wells on SAWS property located above the aquifer in South San Antonio. Water would be stored in the Carrizo, then pumped back out when needed.

“We’re in the Carrizo because it’s a sand aquifer,” said ASR project Manager Michael Brinkmann. “ … the sand in this aquifer is very uniform, very predictable of where the bubble [water] will go. We don’t have to worry too much about faults [and water seepage].”

A greater concern is the rise and fall of the water level, depending on the injection or recovery mode of the ASR process. There’s no doubt; there will be some impact on farmers and ranchers with wells surrounding the SAWS property. However, the effects will be diminished, as proximity to the wells lessens.

Brinkmann said SAWS would be able to predict water levels quite accurately. He conceded that the more shallow wells in the area might require their pumps to be lowered.

“And in our mitigation policy, we would go in and make those landowners whole. It would be at SAWS’ expense,” said Brinkmann. The SAWS board of directors adopted a Carrizo mitigation policy about a year ago as part of a “good neighbor” approach to the pro-ject.

Seventeen wells and four monitoring wells, owned by SAWS, have been drilled at the southern end of Bexar County with a conduit between the wells and a water treatment plant which will also be located on the property.

Besides the water fluctuation, there has been some concern, especially in Wilson County, about the amount of water that SAWS might withdraw from the Carrizo. Fortunately, SAWS and the Evergreen Underground Water Conservation District (EUWCD) signed a water resource protection and manage-ment agreement.

Brinkmann claims that under the terms of the agreement, in 2004 and 2005 SAWS can make a maximum draw of 14,000 acre-feet per year, which is more than the 2 acre-feet limitation to which the standard landowner is limited in the Evergreen district.

Aguilar told the Wilson County News Friday that the 14,000 acre-feet draw would only occur if San Antonio was in a drought situation. In other circumstances, only 6,400 acre feet would be drawn.

“Long term, we believe the water’s there,” said Brinkmann. “But we’ve agreed, beginning in 2006, to limit production to 2 acre-feet annual average or 6,400 acre-feet [for 3,200 acres of land]. It’s what everyone [land-owners] else is held to.”

SAWS will be working with the EUWCD regarding monitoring of pumpage and with the Texas Commission on Environmental Quality on oversight, according to Aguilar.

SAWS literature points out that there are a lot of advantages to the ASR — primarily a large reduction in the water lost by evaporation, since the water is stored underground. Also SAWS claims, the ASR process would allow for an unlimited amount of water to be stored in the Carrizo with a lesser risk of contamination than if kept in a surface reservoir.

“We’re all tied to this environmental area,” said Aguilar, “so we want to be good neighbors. We’re a responsible utility. There’s been extensive amounts of studies that have gone into this, before the construction phase. We wanted to make sure about compatibility issues … that there would be no detrimental effect to the environment.”

According to Brinkmann, they have sampled the water, the geology, the sand, the mineralogy, and even examined the compatibility between the Edwards Aquifer and the sand for-mation in the Carrizo. He said SAWS is looking at the project long-term.

“We’re not investing these dollars lightheartedly,” he said.

The site, featuring a $26 million water treatment facility and a high service pump station that will process 32 million gallons of water a day, will be showcased on 30 landscaped acres complete with cascading water resembling a waterfall. A 6,500-square-foot office building will double as an educational facility.

“It’s pretty cutting edge technology,” said Aguilar. “It’s something we’re capitalizing on, not only as a storage facility, but we can use the administration building as an outreach facility for the neighborhood.”

In addition, the fact that the facility will be built above the aquifer storage site demonstrates the point that the ASR project has very little impact on the land and the environment on the surface.

The ASR project in South San Antonio is the second largest project of its type in the country.
__________________________

Feel free to contact the Wilson County News regarding content or any other questions/concerns.
E-mail reader@wcn-online.com,
P.O. Box 115, Floresville, Texas 78114
830-216-4519, fax 830-393-3219