Aquifer Storage: City of Buda green-lights pilot study

Buda city leaders took another step toward implementing Aquifer Storage and Recovery (ASR) with the approval of a pilot study meant to test the safety of the proposed project.

On Dec. 5, the Buda City Council approved, by a 6-0 vote, a professional services agreement with HDR for the pilot study. Councilmember Remy Fallon was not present at the meeting.

James Dwyer with HDR gave a short presentation to council members regarding the pilot study, whose funding was included in the Water Capital Improvements Fund as part of the 2017 certificates of obligation bonds.

Dwyer said the total cost of construction for the pilot study would be $1.25 million.

Dwyer said $1.1 million is being used for pump and site improvements and $150,000 being used for a new monitor well.

According to city documents, Buda intends to use ASR technology as a “water supply management strategy to reduce or eliminate seasonal peak shortages through water banking.” Buda intends to inject water from the Edwards Aquifer deep into the Trinity Aquifer.

In a later interview, John Dupnik, Barton Springs Edwards Aquifer Conservation District (BSEACD) general manager, said ASR technology allows entities to take a small portion of existing Edwards water and store it in the Trinity Aquifer until it’s needed.

“An ASR system is intended to allow water to be banked in good times and then pumped back out when it’s needed in times of drought,” Dupnik said.

Dupnik said hydraulics associated with the ASR system were actually very simple and only involve having an Edwards production well and injection well in the Trinity Aquifer side by side.

Dupnik said the transference of ASR water supplies would be done by pumping from the Edwards well and then moving the water right over to the Trinity well and injecting it down into the deeper aquifer, meaning no additional piping needed.

But the approval of the pilot study doesn’t mean Buda residents can start expecting the city to be able to utilize the ASR technology right away.

Dupnik said the reason for the various pilot studies was to determine if there will be a reaction between the Edwards water and the Trinity water when they mix.

“We need to look at how the Edwards Aquifer water reacts to the Trinity aquifer when it’s injected in there,” Dupnik said, regarding the possible geochemical implications of the ASR technology.

Dupnik also said that the permitting process for this technology was still in its infancy and requires BSEACD to work very closely with the Texas Commission on Environmental Quality (TCEQ) since the two entities share jurisdiction over ASR activities.

Dupnik said TCEQ has jurisdiction over the water that is injected into the aquifers; BSEACD has authority over the water recovered from the aquifers so they are currently working together to establish a regulatory and permitting structure.

“It’s appropriate for our district to investigate this type of strategy and whether in fact it’s feasible or not,” Dupnik said.

Dupnik could not comment on the pilot study recently approved by the Buda City council but did mention an ASR pilot study at Ruby Ranch near Buda that has been going on for about a year that is showing “real promise.”

Buda Mayor George Haehn said science should drive policy regarding ASR technology.

“I would like to see us look at all viable options so we can expand our available water supply in Buda,” Haehn said.

Dwyer said the earliest possibility for an operating, permitted ASR well would be 2020.

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