by Lane Riggs, staff writer
Ron Green, a scientist at Southwest Research Institute in San Antonio, and his team of hydro-geologists are busy collecting data on and creating a lumped parameter model for the Uvalde Pool, a major reservoir of underground water centered over central Uvalde County and part of the Edwards Aquifer.
Though the project is relatively new, Green said their research in Uvalde has been ongoing for over 20 years.
“For over 20-plus years, we’ve been trying to quantify how much water goes in and out of the Uvalde Pool,” he said.
Over this time, his team has created a conceptualization of the Uvalde Pool river channels – with inflow from the Nueces River channel and outflow through the Knippa Gap.
During Green’s years of research, his team has since realized the Dry Frio River emptied into the Knippa Gap, rather than into the Uvalde Pool.
“That was not known before,” he said. “It might not seem like much, but it’s taken us 20 years to get to this point.”
Amid new discoveries, Green is continuing his research to better understand the Uvalde Pool.
“We’re trying to help Uvalde in their management of water,” he said. “Our computer models and data analysis will help policy makers better understand the Uvalde Pool, so they can adjust rules accordingly.”
In arid areas like Uvalde, or from Austin to El Paso, where Green also works, his team attempts to evaluate water resources. By pinpointing where water comes in and where (and how much) water goes out, Green can better contain said water. Furthermore, periods of reduced precipitation and drought can be prepared for appropriately.
“The Uvalde Pool hinges on recharge, and that happens to be the greatest uncertainty,” Green said. “This tool is going to provide insight and will better inform us of the resources available.”
Although Green imagined the project would take a year, he said his team is flexible and can stretch the project. Additionally, with the project spread over a two-year period, the $100,000 cost, which would be paid by the Uvalde County Underground Water Conservation District if directors approve the idea, might seem more feasible.
Regardless of how long the project takes, Green said it is a medium size project for the three to four hydro-geologists working on the model.
“We will be doing intense data work; it’s heavy lifting,” he said. “And it’s a team effort.”
“We’re going to figure out the capacity of the ponds,” said UCUWCD general manager Vic Hilderbran. “I think of it like running a checkbook. We have to stay on budget before we run out.”
In areas like Uvalde – where the recharge is usually slight – balancing the checkbook is incredibly important.
“Because of this reservoir model, we will have a much better informed sense of the water available,” Green said. “We’ll have a conceptual model of Uvalde resources.”
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