Recharge source, mode and development potential of typical tectonic karst groundwater in the eastern QinghaiXizang Plateau

Objective There are many tectonic karst areas in the east of Qinghai-Xizang Plateau, with complex karst hydrogeological structure, diverse recharge sources and abundant groundwater. Conducting the analysis and research of recharge sources and summarize the plateau tectonic karst cycle law is of great significance for guiding the development and utilization of karst water resources, ecological protection and disaster prevention and reduction.Methods Based on field investigation, flow measurement, hydrochemistry and stable isotope analysis, this paper analyzes the groundwater recharge sources in typical karst areas in the east of Qinghai-Xizang Plateau, the influencing factors of recharge sources and recharge progress were discussed, and suggestions of development and utilization were put forward.Results The results show that the main recharge source of the main karst springs in the eastern Qinghai-Xizang Plateau is atmospheric precipitation. Four recharge modes are established, including direct recharge through fissure in high-level, continuous recharge by high-level lake, continuous seepage recharge in catchment depression, river seepage recharge.Conclusion The reason for the difference of recharge modes is that the eastern Qinghai Xizang Plateau has experienced internal and external dynamic coupling for a long time, in which the internal dynamic control factors are karst formation and evolution history, geological structure and lithologic combination; The external dynamic control factors mainly include meteorology, landform and glacier movement. According to the characteristics of water quality and quantity of karst spring, three development and utilization modes are put forward:the first is karst spring with water quality of class I~III, which can directly expand the degree of development and utilization, the second is brackish water, which can be properly developed and utilized after mixing with other water, and the third is salt water, which can be properly transformed and used for tourism development.