EFFECT OF YUFU RIVER ON CHEMICAL PROCESS OF KARST GROUNDWATER IN JI'NAN, SHANDONG PROVINCE

As one of the main recharge sources of the Jinan karst groundwater, the Yufu River plays an important role in spring protection in Jinan. In this paper, hydrochemistry and isotope are used to analyze variation of ions and mineral dissolutin/precipitation, flow path and scope due to river infiltration. The results indicate the SO₄-Ca-Mg type of river water gradually turns into HCO₃-Ca type of groundwater toward central city springs. Saturation indices of calcite and dolomite decrease, while saturation index of gypsum remains constant due to river infiltration. The data of hydrochemistry and isotope show that fraction of river water in karst aquifer reaches to 48%in the area from the Cuima to Manzizhuang. The river water occupies respectively 50% and 5% at 3 and 8 kilometers east to the Yufu River, showing less effect on the spring areas.