Study planned for Trinity Aquifer sustainability
A new study to determine the sustainable amount of water that can be produced from the Trinity Aquifer received support from the Hays County Commissioners Court.
On October 22, Hays County approved an interlocal agreement that will involve installation of two groundwater monitor wells near Jacob’s Well and sampling of groundwater in the vicinity of Jacob’s Well. On October 1, Travis County approved the continuation of groundwater study for southwest Travis County. Recent strong support from Hays and Travis Counties provides funding that will help fill critical data gaps for the Trinity Aquifer Sustainable Yield Study.
The sustainable yield of an aquifer is the amount of groundwater that can be pumped from the aquifer without causing unreasonable impacts to other water-supply wells and springs. The Trinity Aquifer is the primary groundwater supply for Hill Country residents in Hays and Travis Counties, and Trinity Aquifer springs help sustain iconic Hill Country streams. With limited water resources and exceptional population growth in Hays and Travis Counties, the effects of groundwater pumping are already being seen with reduced spring flow and longterm lowering of water levels in the Trinity Aquifer and underscore the importance of science-based policies.
Some of the most important questions the study will address are based around the current Desired Future Conditions of the aquifer. The DFC determines how much water pumping is available to be permitted. The study will look at the current DFC and determine if it is appropriate for sustainability. It will also look at how to handle historical permitting in the Trinity Aquifer and if certain areas like Jacob’s Well should be managed separately.
For over 10 years, the Barton Springs/Edwards Aquifer Conservation District (District) has been collaborating with the Hays Trinity Groundwater Conservation District and local and regional organizations to study the Trinity Aquifers of Hays and Travis Counties. Since annexation of an additional portion of Hays County into the District in 2015 (with passage of House Bill 3405), these efforts have increased substantially. These efforts include geologic investigations, aquifer recharge studies, water-level studies, water-quality analyses, aquifer (pumping) tests, development of a conceptual model, and groundwater modelling.
To effectively manage an aquifer system, scientists and managers must have a good understanding of how the aquifer functions. This is the foundation for science-based policies. Understanding of aquifer dynamics comes from a broad spectrum of studies and data. From these studies, scientists and groundwater managers can determine the sustainable yield of an aquifer.