Institute of Hydrogeology and Environmental Geology, CAGS, Shijiazhuang, 050061, Hebei, China.
Key Laboratory of Groundwater Sciences and Engineering, Ministry of Natural Resources, Shijiazhuang, 050061, Hebei, China.
Sci Rep. 2022 Aug 29;12(1):14661. doi: 10.1038/s41598-022-18960-9.
Karst groundwater plays important roles as a water supply and in sustaining the biodiversity and ecosystems of the eastern Qinghai-Xizang Plateau. Owing to the stratigraphic structure, high tectonic activity, and changeable climate of the region, the recharge source, runoff path, and dynamic characteristics of karst groundwater are highly complex, which poses challenges with regard to the protection of water resources and ecology. This study identified the origin and flow processes of karst groundwater in the glacial lake area of the Jinsha River fault zone using satellite remote sensing, hydrochemical and isotope analyses, and flow measurements. Results showed that active faults control the distribution of glacial lakes and the recharge, runoff, and discharge of karst groundwater. Glacial lake water is an important source of karst groundwater in the Jinsha River fault zone area. Specifically, glacial lake water continuously recharges the karst system via faults, fractures, and karst conduits, thereby maintaining the relative stability of karst spring flows. Through hierarchical cluster analysis, two main runoff conduits of karst water were distinguished: one along the Dingqu Fault and the other along the Eastern Zhairulong Fault, which together account for 59% of the total regional karst groundwater flow. The elevation difference between the recharge and discharge areas of the main karst springs is > 1000 m. Groundwater runoff is fast and residence time in the aquifer is short. The dissolution of calcite and dolomite mainly occurs during transit through the groundwater system, and cation exchange is weak. Therefore, the regional karst springs are predominantly HCO-Ca·Mg type. To protect regional karst water resources and ecology, the monitoring and protection of glacial lakes should be strengthened.
喀斯特地下水在为青藏高原东部提供供水和维持生物多样性和生态系统方面发挥着重要作用。由于该地区的地层结构、高构造活动和多变的气候，喀斯特地下水的补给源、径流路径和动态特征非常复杂，这给水资源和生态保护带来了挑战。本研究利用卫星遥感、水文地球化学和同位素分析以及流量测量，确定了金沙江断裂带冰川湖地区喀斯特地下水的来源和流动过程。结果表明，活动断层控制着冰川湖的分布以及喀斯特地下水的补给、径流和排泄。冰川湖是金沙江断裂带地区喀斯特地下水的重要补给源。具体而言，冰川湖通过断层、裂隙和喀斯特管道不断补给喀斯特系统，从而维持喀斯特泉流量的相对稳定。通过层次聚类分析，区分出两种主要的喀斯特水径流通道：一条沿定曲断层，另一条沿东扎龙断层，两者共占区域喀斯特地下水总流量的 59%。主要喀斯特泉补给区和排泄区之间的高程差>1000 m。地下水径流速度快，含水层停留时间短。方解石和白云石的溶解主要发生在地下水系统的传输过程中，阳离子交换较弱。因此，该地区的喀斯特泉主要为 HCO-Ca·Mg 型。为了保护区域喀斯特水资源和生态，应加强对冰川湖的监测和保护。
