The Edwards Aquifer (EA) in Central Texas provides water supply for over two million people and contains springs that are hydrologically and ecologically important to the region. The residence time of groundwater in the EA ranges from a few days to many thousands of years, since water in the aquifer is contained and transported within both matrix porosity and large conduits. In this study, stable isotopes of water from five springs are investigated for tracing the origin of water and hydrological processes in the EA system during 2017–2019. There is a quick response of the isotopic signals measured at these springs to changes in the isotopic compositions of precipitation. By utilizing an isotope mixing model, we have identified sources of water for these springs with a bi-modal distribution of groundwater supply in the EA: water supplied from deep groundwater with a longer residence time (an average of 67%) and supplemental epikarst interflow with a shorter residence time (an average of 33%). The evolution of hydrochemical water types from HCO₃–Ca to HCO₃·Cl–Ca·Mg along the EA flowpaths indicates that inputs from epikarst interflow are greater in springs within the artesian zone than the springs within the contributing zone.

德克萨斯州中部的爱德华兹含水层 (EA) 为超过 200 万人提供供水，并且包含对该地区具有重要水文和生态重要性的泉水。地下水在 EA 中的停留时间从几天到几千年不等，因为含水层中的水包含在基质孔隙度和大型管道中并在其中传输。在这项研究中，研究了 5 个泉水的稳定同位素，以追踪 2017-2019 年 EA 系统中水和水文过程的起源。在这些泉水测得的同位素信号对降水同位素组成的变化有快速响应。通过利用同位素混合模型，我们已经确定了这些泉水的水源，其地下水供应在 EA 中呈双峰分布：来自具有较长停留时间（平均 67%）的深层地下水和具有较短停留时间（平均 33%）的补充表层岩溶互流供水。HCO 水化学水类型的演变沿 EA 流动路径的₃ –Ca 到 HCO ₃ ·Cl-Ca·Mg 表明来自表岩溶互流的输入在自流带内的泉水比贡献带内的泉水大。