CHARACTERIZATION OF SPRING FLOWS CONTRIBUTING TO INDEPENDENCE CREEK, TERRELL COUNTY, TEXAS

Water resources in arid west Texas are crucial to sustain both human society and wildlife habitats. The karstic Edwards-Trinity Plateau Aquifer provides high quality water to humans and animals alike, often through major springs. Independence Creek, a tributary to the Pecos River as it incises the Cretaceous aquifer rocks, has both ephemeral and perennial reaches. Live water from the perennial reach is derived from two springs: Vanderbeek and Caroline springs, with their combined flow typically doubling the flow of the Pecos River and diluting the brackish surface water with fresh spring-fed water as the river heads south to eventually flow into the International Amistad Reservoir.

Much of the perennial reach of Independence Creek is part of a preserve owned and managed by The Nature Conservancy (TNC) of Texas. Caroline Springs lies within this preserve, part of the former “Oasis Ranch.” TNC collaborated with the field geology class, “Applied Karst Hydrogeoloy,” at the Jackson School of Geosciences – University of Texas at Austin, to characterize the spring flow from Caroline Springs and its relative contribution to Independence Creek and the Pecos River in the fall of 2022. The class, consisting of 10 students and a professor, quantified flow emerging directly from the springs, creek flows, and basic water quality from the springs, creek, and river.

The class used a combination of an acoustic doppler profiler, acoustic velocity meters, and temperature/specific conductivity (sp.cond.) meters over several days to characterize the quantity and quality of water in this system. Results show that Caroline Springs contributed ~6 cubic feet per second (cfs) to Independence Creek with a sp.cond. of 951 uS/cm. This springflow contributed to the ~13 cfs (1361 uS/cm) from upstream Independence Creek, assumed to come from Vanderbeek Springs to total ~19 cfs (1163 uS/cm) flowing down to the confluence with the Pecos River (5540 uS/cm). The increase in flow volume and fresh quality water from this spring system lowered sp.cond. to 3180 uS/cm in the river below the confluence. Independence Creek and its springs are a vital part of the Trans-Pecos region of Texas and require long-term monitoring and protection to ensure continued flow as threats such as climate change and anthropogenic extraction stress the water resource.