Investigating the hydraulic connectivity of a complex karst aquifer system is an important research topic for sustainable operation and optimization layout of karst groundwater exploitation and recharge. However, the identification of preferential sites of recharge and exploitation is usually subject to regional hydrogeology conditions and the mechanisms of recharge and exploitation. The conventional research methods of hydraulic connectivity often have some limitations. In this study, we

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... ped an improved grey amplitude relation model to explore the hydraulic connectivity in Jinan spring catchment and presented a quantized evaluation index water table fluctuation relation degree (WTFRD) using karst groundwater table data in Western Jinan and Jinan spring groups from 2014 to 2017. Results showed that the total WTFRD was 0.854 between Western Jinan and Jinan spring groups when the external distraction for karst groundwater table was the smallest, which was in high relation degree grade. Meanwhile, the change rules of karst groundwater table in the two sites were basically the same. Accordingly, a high connectivity occurred between the two karst aquifers from a statistical perspective, and further illustrated that Western Jinan could be selected as preferential experiment sites. A comprehensive case in Jinan spring catchment indicated that the WTFRD provided a preliminary idea to investigate hydraulic connectivity quantitatively. This method could be considered as a pre-study of the conventional experiments to form a high-efficiency and low-cost combined method, which has great potential and merits further study.