Characterization of karst conduit structure based on multisource artificial tracer test: A case study of the Cangpuwa underground river in Guizhou Province

Artificial tracer test is an important research method in the field of karst hydrogeology. In this study, to understand the distribution characteristics of karst conduits more comprehensively, multisource tracer tests were carried out on the Cangpuwa underground river in the base flow period and precipitation conditions. The results showed that tracers from Shuiqing, Huangliancun, and Liaojiapo were detected in the base flow period and precipitation conditions. The tracer recoveries under precipitation conditions were 88.12%, 90.01%, and 84.01%, respectively, indicating that the Cangpuwa underground river was a multisource and single-sink underground river. According to the tracer transport characteristics in both the base flow period and precipitation conditions, a conceptual model of the Cangpuwa underground river karst conduit structure was constructed. The flow path from Shuiqing to Cangpuwa had the largest curvature, the flow path from Huanglian to Cangpuwa was mainly a karst conduit, there were two channels on the flow path from Liaojiapo to Cangpuwa, and there was a dissolved pool near the outlet of the underground river. The research results can provide a basis for the investigation and exploitation of water resources in complex karst underground rivers.