GIS-based regionalization of a karst water system in Xishan Mountain area of Taiyuan Basin, north China

SummaryA clear description of the structural features and path of groundwater flow for a karst water system is a basis for establishing a hydrogeologic conceptual model in a basin. In a case study of the karst system of Xishan Mountain of Taiyuan Basin, typical of hydrogeologic systems in north China and elsewhere in the world, we extracted quantitative information of hydrogeologic structure and regionalized the interior structure of the karst water system using a geographic information system (GIS) technique. The information, extracted from lithofacies paleogeography, geology, tectonics and hydrogeology, includes the isolines of the top of the regional aquiclude, the projected section of both planes of a fault, and plotting the regional saturated zone, the passage zone, and the local saturated zone in the karst water system. We analyzed the distribution range of karst water aquifers of Xishan Mountain, the permeability of the stratum, the boundary characteristics and the relationship between the interior and exterior system. It was essential to clarify the interactions among the karst water systems of the mountain area, surface water, pore water in the Caenozoic unconsolidated materials and the deep karst water under the basin.This research shows that the study area can be divided into two subsystems: (1) Lancun spring and Jinci spring, and (2) Xiye spring. Subsystem (1) includes the regional saturated zone, the passage zone and the local saturated zone. We demonstrated that Lancun spring and Jinci spring belong to the same regional karst water system. Subsystem (2) results from the perched groundwater formed by a local impermeable bed. The results show that this type of integrated analysis is a useful method to extract hydrogeologic information and can be applied to a mountain area without much investigated data, in particular where carbonate formations or layered permeable rock are the most important aquifers.