Aqua Aquifer Test – Coordinated Monitoring Effort

Aqua Texas drilled two test wells in September 2022 near the FM 2325 and Ballpark Rd intersection.  In collaboration with the Hays Trinity Groundwater Conservation District and The Watershed Association, Aqua Texas plans to perform an aquifer test to provide pumpage data and water level responses to help determine if pumping the new wells will have an impact on flow at Jacobs Well and other nearby wells.

The Watershed Association has supported the aquifer test and is developing a monitoring plan in collaboration with surrounding well owners and groundwater organizations.  Dates for the Aquifer Test are still being discussed, but the test is anticipated to happen early this summer.

Click for Board Briefing with overview of test, monitoring sites map, and coordinated monitoring table (pdf)

The Watershed Association supported a variance request to allow an Aqua Texas Woodcreek Phase II Aquifer Test during drought for the following reasons (click for full Watershed Association comment letter presented to the Hays Trinity Groundwater Conservation District):

      1. The Watershed Association supports any effort to reduce pumpage in the Jacob’s Well Groundwater Management zone. Aqua Texas has stated this is their intention with the two new test wells; however, a pumping agreement is advised to formalize this intention.
      2. The two Aqua Test Wells could provide a water supply that does not impact Jacob’s Well spring flow and existing groundwater users, if they have been completed in a section of the aquifer that isolated from Jacob’s Well. It is imperative that this be tested by a robust, coordinated monitoring effort during an aquifer test.
      3. The two Aqua Test Wells are adjacent to the Jacob’s Well Groundwater Management Zone (JWGMZ) and within the Tom Creek Fault Block. This fault block is known to have complex, karst groundwater dynamics.  While policy established the boundary of the GMZ, it is critical to test and measure potential impacts of pumpage in that area on Jacob’s Well and surrounding wells.
      4. Drought conditions and pumping above permit and drought curtailment limits are currently occurring, these conditions would allow measurement of pumping impacts during the most important times—low to no flow at Jacob’s Well and exceptionally low groundwater levels in the surrounding Middle Trinity aquifer. Scientifically, timing the aquifer test during these conditions would provide valuable data.

Purpose of the aquifer test
The pump test will provide pumpage data and water level responses to help determine if pumping the new wells will have an impact on flow at Jacobs Well and other nearby wells.

Aqua Texas Test Wells
During the proposed aquifer test, the two test wells will be pumped simultaneously with a combined pumping rate of approximately 390 gallons per minute.

Pumpage volume
Approximately 1,000,000 gallons will be pumped and discharged to the land surface.

Collaborative field effort
Planning and discussion to monitor approximately 20 sites within 2 miles of the test wells have included input from Aqua Texas, HTGCD, the Watershed Association, Wimberley Water Supply Corporation, Edwards Aquifer Authority, Barton Springs Edwards Aquifer Conservation District, City of Wimberley, City of Woodcreek, and Hays County.  (Board briefing with map and monitoring site table)

Monitoring overview
Approximately 20 wells plus Jacobs Well will be monitored for water levels during an initial 7-14 day background monitoring period, followed by a 48-hour pumping period, then a recovery period.

Monitoring data:  Data will be distributed between participating collaborators for analysis.