water Article A Complicated Karst Spring System: Identified by Karst Springs Using Water Level, Hydrogeochemical, and Isotopic Data in Jinan, China Yi Guo 1,2,3 , Dajun Qin 1,2,3,4,*, Lu Li 1,2,3, Jie Sun 1,2,3, Fulin Li 5 and Jiwen Huang 5 1 Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;
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[email protected] (J.S.) 2 Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China 3 University of Chinese Academy of Sciences, Beijing 100049, China 4 Academician Zhaiming Guo working station, Sanya University, Hainan 572000, China 5 Water Resources Research Institute of Shandong Province, Ji’nan 250013, China;
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[email protected]; Tel.: +86-010-8299-8589 Received: 27 March 2019; Accepted: 30 April 2019; Published: 6 May 2019 Abstract: The Jinan karst spring system, discharged by 108 springs in 2.6 km2 city center area of Jinan, China, has been suffering lower regional groundwater levels, which threatens the karst springs outflowing and aquatic ecological civilization. For better spring protection, monthly hydrogeochemical and isotopic investigations were conducted in four representative karst springs (Baotu Spring (BTQ), Heihu Spring (HHQ), Zhenzhu (ZZQ), and Wulongtan Springs (WLT)) in 2016. Results showed that the BTQ, WLT, and ZZQ had similar hydrogeochemical and isotopic behaviors, which were different with that of HHQ. By combining the daily water level data with monthly hydrogeochemical and isotopic data of BTQ and HHQ, the hydrogeological processes of the two neighboring karst springs (470 m apart) are distinguished.