Recognition Of Heterogeneity Shanxi Niangziguan Spring Aquifer Cross Wavelet Analysis

Karst are widely distributed in the globe, only in china, its area is up to346.3×104km2, which takes25%of the whole, karst is a special type of landscape, both in characteristic and in structure, in the southwest part of china, and the vast semiarid areas in the northern china, there are plenty of karst distributions. The regional precipitation is the main source of karst groundwater recharge in the northern china, except for other factors, for instance, the evaporation, part of precipitation penetrates to underground, through aeration zone into saturation zone, then forms and discharges karst groundwater, therefore, precipitation are one of the vital factors that influenced the groundwater level of karst areas.Karst aquifers are highly heterogeneous and exhibit hierarchical permeability structures or flow paths. Conduits and fractures typically account for less than1percent of the porosity of the aquifer, but more than95percent of the permeability. For the purposes of karst groundwater resources management, as well as of protection strategies against potential contamination, understanding heterogeneity of an entire aquifer system is generally more important than information about a specific spring, which is not suitable for the economically less developed with large range, that is, not proper for the northern China. More cost effective methods are essential to identify the heterogeneity of karst aquifer in a tremendous karst area with scarce data.Since the transmission of pressure wave is actually the transmission of energy, in order to study and analyze the propagation of groundwater, this paper applied the wavelet analysis into the karst groundwater research project. The wavelet analysis could offer the multi-resolution analysis both in the time and frequency domain. The wavelet is based on the Fourier analysis; it is a rapidly developed brunch of mathematics and applied mathematics, wavelet analysis overcomes the shortages of traditional Fourier transform and window Fourier transform, which gives a effective way of high flexibility, we can choose the precision and accuracy of time and frequency. Due to its marked advantages on multi-time scale analysis and hydrological forecasting, the wavelet analysis has been widely recognized by more ’and more researchers and hydrologists, and now been extensively used in hydrology.In this project, we introduce cross wavelet transform to analyze the relationships between precipitation and spring discharge and identify the heterogeneity of karst aquifer. In high karstification areas, the precipitation signal can penetrate aquifer relative easily and reflect to spring discharge. Then the precipitation and spring discharge are close related, and the values of cross wavelet transform coefficients are large. On contrary, in the low karstification areas, the values of cross wavelet transform coefficients are small.We applied the method to Niangziguan Springs Basin China to detect the heterogeneity of the karst aquifer. Results showed that Pingding County and Yangquan City have high degree of karstification, Xiyang County and Shouyang County have middle degree of karstification, and Yuxian County, Heshun County, and Zuoquan County have low degree of karstification. The results agree with the geological structure of Niangziguan Springs Basin.