地质科技通报 (Nov 2024)

Identification and genetic mechanism of recharge sources in groundwater-rich area of Changxiao karst water system in Jinan City

  • Yi LIU,
  • Fengxin KANG,
  • Wenqiang ZHANG,
  • Qingyu XU,
  • Peng QIN,
  • Qiang ZHAO,
  • Jialong LI,
  • Yang CUI,
  • Haibo SUI,
  • Tingting ZHENG

DOI
https://doi.org/10.19509/j.cnki.dzkq.tb20240122
Journal volume & issue
Vol. 43, no. 6
pp. 292 – 305

Abstract

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Objective and methods In this study, the hydrochemical method and self-organized neural network (SOM-KM) coupling method were employed to identify recharge sources and reveal the water-rich mechanism in the karst groundwater-rich area of the Changxiao karst water system in Jinan City. The contribution ratio of karst groundwater recharge sources in the karst groundwater-rich area was quantitatively calculated using the end-element mixed model. The enrichment mechanism of karst groundwater is explored by combining with topography, geological structure, stratigraphic lithology, and catchment conditions. Results The results showed that the karst groundwater in the catchment drainage area had similar water chemistry to that in the southern recharge area, the karst groundwater in the lateral runoff area, and the Yellow River, indicating a close hydraulic connection. This implies that the karst groundwater in the catchment drainage area is recharged by three sources: The southern mountain area, the karst groundwater in the lateral runoff area, and the Yellow River. The contribution ratios of the three components are 75.09%, 21.02%, and 3.89%, respectively. Carbonate rocks are widely distributed, and fissured karst is well developed in the accumulation and discharge areas, especially in the Maji-Xiaoli-Guide area. Moreover, there are abundant karst groundwater recharge sources in this area. During the runoff process of karst groundwater from southeast to northwest, it is impeded by sandstone and mudstone in the north. As a result, it accumulates in the contact zone between soluble rock and insoluble rock, thus forming impeded-type karst groundwater-rich structures. Conclusion Revealing the enrichment mechanism of karst groundwater in the Changxiao karst water system can provide scientific support for accurate calculations of recoverable resources and the protection of the springs in Jinan.

Keywords