Recognition of the critical hydrogeological conditions of the Jinci Spring and Lancun Spring in Shanxi

The Jinci spring and Lancun spring are the famous springs in Shanxi province. Due to the changes in natural conditions and the effect of human activities, hydrogeological conditions of the catchment area of the springs have changed, and they became zero-flow at the end of the last century. Based on the previous research results, current investigation and hydrogeological drilling data, new understanding of hydrogeological conditions of the groundwater systems of the Jinci spring and Lancun spring are put forward through analyses of the karst groundwater flow field. The boundaries of the groundwater systems of these two springs are corrected, with seven differences compared with the boundaries delimited by the Shanxi government. According to the latest boundary, the catchment area of the Jinci spring increases from 2 030 km2 to 2 713 km2 and that of the Lancun spring increases from 2 500 km2 to 2 614 km2. The Fenhe reservoir, which used to belong to the Jinci spring system, has the leakage recharge to the Jinci spring system. This is one of the main causes of the increase in the karst groundwater levels in the Jinci spring spring. The Pandao-Majiashan fault zone is found to be a groundwater-enrichment region. It is also a transfer zone, in which the karst groundwater in the Cambrian aquifer flows to the Ordovician aquifer. The strong groundwater flow zone along the Nanyu-Duerping Coal-the junction of Guandi Coal and Baijiazhuang Coal-Chiqiao-Jinci Spring is also identified in the Jinci spring system. The results can provide a scientific basis for groundwater resources assessment and the reasonable exploration of the karst groundwater and the implementation of programs of reflow of the Jinci spring.