Abstract:
The Jinan spring is a typical representative of karst springs in North China. Since the 1970s, the rapid urbanization process and excessive exploitation of groundwater have resulted in zero-discharge of the spring water. Although the measures to supplement the water source have been taken in recent years, the effect is not ideal. The basic reason is the lack of scientific basis for the selection of artificial supply sources. In order to determine the recharge ratio of different aquifers to the spring water in the Jinan spring area, according to the observations of the spring water level and water temperature, water quality index test, frequency analysis of spring water conductivity, and combined with the geological structure conditions of the spring area, the difference in spring water recharge sources is studied, and the recharge ratio of different aquifers to the spring water in the Jinan spring area is determined. The results show that (1) the recharge ratio of the karst aquifers to the Baotu Spring and Heihu Spring is different. The recharge ratios of the Baotu spring and Heihu spring from the Zhangxia formation aquifer are 31%-54% and 24%-31%, respectively, and supply water from the limestone aquifer of the Ordovician Limestone-Cambrian Fengshan Formation accounts for 45%-68% and 68%-75%, respectively. (2) The recharge sources of the Zhenzhu Spring and Tanxi Spring are the same. The recharge ratios of the Tanxi Spring and Zhenzhu Spring from the Zhangxia Formation are 60%-70% and 60%, respectively. The recharge ratios of limestone aquifer of the Ordovician Limestone-Cambrian Fengshan Formation are 15%-17% and 22%-25%, respectively. The recharge ratios of artificial recharge are 8%-21% and 13%, and the recharge ratios of pore water and fissure water are 6% and 5%-6%. (3) The characteristics of spring water temperature show that the groundwater of the Zhenzhu Spring and Tanxi Spring is mainly supplied by groundwater of deep circulation, and there are pore water and fissure water to supply the spring water, The influence of recharge water on the Zhenzhu Spring and Tanxi Spring is obvious. (4) Spring water level dynamics show that there are some differences in the source and direction of recharge between the Heihu spring and Baotu spring in dry and wet seasons, and the karst development in the limestone aquifer of the Ordovician Limestone-Cambrian Fengshan Formation is stronger in the Heihu spring area. Macroscopically, the spring water supply comes from the widely distributed Cambrian-Ordovician limestone area. Microscopically, the recharge intensity of different karst aquifers to the four major spring groups is obviously different. The Ordovician aquifer is an important recharge source of the spring water. The Ordovician limestone area is the site of artificial recharge source for maintaining the emergence of the spring water.