Abstract:In order to study the influence mechanism of dynamic change of karst springs, taking Jinan spring area as an example, this work studies calculated the fractal dimension values and stability index of data series of various elements by time series fractal method according to the monitoring data of spring water level, rainfall, groundwater exploitation and artificial recharge in Baotu Spring and Heihu Spring since the closure of groundwater supply source in 2003.The results show that the fractal dimension values of spring water level at ten-day scale are larger than that of spring water level at monthly scale. The fractal dimension of precipitation at rainfall stations in Ordovician limestone distribution area is smaller, but the condition of precipitation infiltration and recharge are better, so it is more closely related to the fluctuation of water level of spring group. Among the influencing factors of spring water level, the stability of recharge factor is the worst, which is very vulnerable to the interference of external factors.
The grey correlation degree was used to validate and analyze the degree of association between rainfall, artificial exploitation, artificial recharge with water level of Baotu Spring, which are 0.858, 0.647 and 0.667 respectively, and the degree of association with water level of Heihu Spring are 0.859, 0.646 and 0.668 respectively. The overall order of correlation degree is rainfall > artificial recharge > artificial exploitation, indicating that atmospheric precipitation is the primary factor affecting spring water level dynamics since 2003, not artificial exploitation. Based on the analysis of the evolution of spring resources, the regression analysis of fractal dimension and dynamic dimension of spring water level shows that the Ordovician limestone distribution area is more suitable for artificial recharge of spring water. The results provide a reference for the protection of Jinan karst spring.