By Marty Kufus

SAN ANTONIO — A proposal for large-scale aquifer pumping and export in Wilson County was cut back June 28 as regional planners accepted a new limit set by a rural ground-water district.

As a result, Wilson County’s ground-water contribution in a 50-year regional plan dropped by nearly 80 percent.

It fell to 11,196 acre-feet per year from a maximum of about 50,000, as earlier proposed in planning for the 20 1/2-county region.

The Evergreen Underground Water Conservation District’s board had voted, the day before in Jourdanton, to establish a Carrizo Aquifer “safe yield” and set aside water for Wilson County’s agricultural irrigation and possible industrial development.

Planner Mike Mahoney, who is the Evergreen’s general manager, announced at the San Antonio meeting that recent engineering studies suggest the Carrizo Aquifer’s recharge (slow replenishment by rain) is 43,852 acre-feet a year in Wilson County.

The county’s yearly consumption is calculated at 22,656 acre-feet, leaving 21,196 acre-feet in the Carrizo before pumping would exceed recharge.

But the Evergreen board also set aside 10,000 acre-feet a year total for the county’s future industry and irrigation.

Until better scientific data are available, Mahoney said, the Evergreen’s board believes “there is about 11,000 acre-feet of water [a year] in Wilson County that could be available for regional plans.”

The regional options for Carrizo pumping were based on data from the Texas Water Development Board.

An acre-foot is 325,860 gallons, or enough for about eight people a year.

None of the 18 other voting planners present argued against, or even strongly questioned, the four-county Evergreen district’s action.

But it did have a significant effect.

“If we’re being driven away from Wilson County,” remarked planner Con Mims, executive director of the Nueces River Authority, then other water sources must be identified “as these drop off the table.”

Also during its day-long workshop, the South Central Texas Regional Water Planning Group took a surprising leap toward creation of the regional plan due in January in Austin.

In a two-hour jam session that afternoon, the Region L planners chose water options common to five theme-driven “alternative plans”; then, added some other possible projects that hold promise — including the prospect of a San Antonio-area entity buying 100,000 to 150,000 acre-feet a year from the Lower Colorado River Authority and piping the water.
These newly assembled options were christened the “hybrid plan” — first round.

If no new water sources are developed, the region’s year-2050 shortfall has been forecast at 400,000 acre-feet, even allowing for conservation
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No ‘Cibolo’ — for now

This initial list in the “hybrid” plan left out a controversial option for a 16,000-acre “Cibolo Reservoir” in Wilson County.

The Region L planning group has recognized the option’s expense (around $500 million), environmental and social impacts, and local public opposition.

The Cibolo Reservoir’s absence in last week’s “hybrid” list, however, does not mean the option is dead, according to discussion.

The San Antonio Water System needs to be able to bank excess winter water for a peak summer demand, one planner said.

“Storage — that’s what I need,” Mike Thuss, president and chief executive officer of SAWS, told fellow planners. “I did not say reservoir.”

At that point, the discussion turned to aquifer storage and recovery, or ASR.

[The San Antonio Water System already has an ASR test project underway in extreme southern Bexar County, in a portion of the Carrizo Aquifer (March 22 Wilson County News).

[As much as 67,000 acre-feet of Edwards Aquifer and/or treated river water could someday be injected and stored underground, awaiting withdrawal. If successful, the ASR project could be expanded into Wilson or Atascosa county — with the approval and cooperation of the Evergreen.]

Mahoney was asked what he thought about ASR.

He replied that “the issue is the chemical compatibility of the waters — that’s the question.”

Another possible storage site for a San Antonio pipeline, in the long run, is Corpus Christi’s Choke Canyon Reservoir.

But that would require interregional negotiations — and municipal officials in Corpus Christi reportedly fear public opposition there to involvement in “a San Antonio water plan,” according to discussion.

“It’s important that, number one, we support each other in our negotiations with our neighbors in the next basin,” Thuss said to the other planners. He was referring either to Choke Canyon Reservoir or the lower Colorado River.

Consultants HDR Engineering, Inc., will analyze the “hybrid” list to determine whether the assembled options are sufficient to meet projected water needs even during a “drought of record.”

The engineers also will continue studying one of the five alternative plans, a complex “recharge and recirculation” scheme to keep the Edwards Aquifer as full as possible for pumping while ensuring spring flows.

Part of Region L’s challenge is San Antonio’s current reliance on the Edwards, which feeds two springs that are habitat to federally protected endangered species.

The Region L planning group’s next monthly meeting will be held Thursday, July 6, beginning at 10 a.m., in the American Legion Hall in Cuero.

It is open to the public.