By Anton Riecher
Plans to apply for grants and funding to support the Medina County Regional Water Alliance’s proposed 50,000 acre-foot aquifer storage and recovery project have been approved by the Texas Water Development Board planning group for central Texas.
Russell Persyn, engineering consultant on the project, reported during the MCRWA’s Nov. 5 meeting in Hondo that he had been conferring with the TWDB’s Region L planning group and a decision about including the project in the latest draft of the state water plan that was expected on Nov. 7.
“Since the last time (Region L) met the regional planning group has put together the project,” Persyn said. “They’ve presented it to their executive committee with no issues there.”
Aquifer storage and recovery is the use of a well to store potable water in a suitable aquifer during times of plenty to be withdrawn during periods of drought. Supporters of the project have compared it to a bank account.
Persyn’s presentation on Nov. 5 included an extensive update on planning with cost now projected at nearly $480 million since Region L became involved.
“We were north of $700 million when we started talking, so obviously that kind of got my attention when I was working with them,” he said.
The project has now been split into two phases, one to be completed in 2040 and the other to be completed in 2080. Phase one will included 10 wells for injecting water into the brackish layer of the Trinity Aquifer. Phase two will include another nine well, plus pumps and pipelines.
A water treatment plant for disinfection with a capacity of 18 million gallons per day will be built, plus transmission pipelines and various interconnections. The project will also include a pump station.
Persyn said the ASR will be located near Siphon 2 in the Bexar Medina Atascosa Water Control and Improvement District No. 1 delivery system located in the northern part of the Trinity Aquifer.
Sources for treated water to be injected into the aquifer will be the Edwards Aquifer and Bexar Medina Atascosa Water Control and Improvement District No. 1. Chief sponsors for the project will be Yancey Water Supply Corporation and the East Medina County Special Utility District.
Annual yield expected from the project is 12,500 acre-feet. That yield is distributed between 10 participating agencies and communities, including Yancey WSC, East Medina County SUD, West Medina Water Supply Corporation, Benton City Water Supply Corporation, and the cities of Hondo, Castroville, Devine, Lytle, LaCoste and Natalia.
The expected share for the city of Devine is 439 acre feet by 2040 and 878 acre feet by 2080. Lytle will get 403 acre feet by 2040 and 806 acre feet by 2080. Natalia gets 151 acre feet by 2040 and 302 acre feet by 2080. LaCoste gets 123 acre feet by 2040 and 246 acre feet by 2080.
Yancey WSC is expected to get 1,193 acre feet by 2040 and 2,386 by 2080. East Medina County SUD gets 870 acre feet by 2040 and 1,740 acre feet by 2080.
Cost of facilities needed for the project is projected at $166.7 million. Total annual unit cost to operate the ASR project is projected at $1,652 per acre foot of water. Minus debt service, the annual cost per acre foot drops to $360.
According to Persyn, the $480 million total cost projected by Region L may fail to take into account the full cost involved in disinfecting water by means of chlorination before injecting it into the aquifer, Persyn said.
“Right now we’re contemplating using surface water,” he said. “I think the level of treatment required might be in excess of that strategy.”
Also addressing the MCRWA meeting was Tim Loftus, general manager of the Barton Springs/Edwards Aquifer Conservation District which would issue permits for drilling injection wells for the new ASR project. Loftus has also served on the TWDB’s water conservation advisory board.
Loftus focused on the district’s work issuing permits for an ASR operated by the Ruby Ranch Water Supply Corporation in Hays County. That project involved four permits involving the Edwards and Trinity aquifers and the use of a well originally permitted for withdrawal of nearly 20 million gallons of water a year from the Trinity aquifer.
That well was later converted into an injection site for the Ruby Ranch ASR, Loftus said.
“No injection is allowed during a drought,” he said. “They can withdraw, of course, whatever has been injected.”
Loftus also reviewed many of the techniques involved in keeping the fresh water injected into the aquifer separate from the untreated water that already exists.
“You’ve got to take that non-native water, inject it, and kind of push aside the naïve water so that you’ve got this buffer of new water that is being injected,” he said. “Of course, you’re going to have different water chemistry and reactions when you take Edwards water and inject it into the Trinity aquifer.”
Cole Ruiz, an attorney with the law firm of Lloyd Gosselink, representing the Yancey WSC, asked about measures that Ruby Ranch took to protect its water from withdrawal by others. Loftus said responsibility for protecting it would fall to the conservation district.
“You can’t just drill a well without obtaining a permit even if it should be for agricultural purposes or domestic water supply,” he said.
The meeting also heard from Travis Pruski, chief operating officer with the Nueces River Authority on its plans to develop a large-scale seawater desalinization plant in San Patricio County that would serve central Texas.
“We are looking at building a massive supply between 300 million to 500 million gallons within the next three to five years,” Pruski said.
He said the river authority is working on “leases, permits and designs as we speak.” However, no estimate on the eventual cost of the project exists at this point “other than on the backs of napkins. More details are expected in the coming months,” he said.
The Nueces River Authority serves as a regional water resource planning agency for a 22 county area of South Texas, monitoring state and federal activities that could affect the Nueces Basin. The city of Corpus Christi has its own proposed desalinization project that is expected to produce 30 million gallons by 2030.
Pruski said the NRA project would involve extending a major pipeline into central Texas that would reach Medina County and the surrounding region. His visit to the MCRWA meeting was to gauge local interest in participating.
“This is a massive statewide project,” Pruski said. “The state’s plan is to take that water as far as humanly possible. They want to have two or three plants like ours in different places in the state to handle our water needs.”
The next meeting of the Medina County Regional Water Alliance is scheduled for 10:30 a.m. on Dec. 2.