XLKarst, un outil Excel pour l'analyse des séries temporelles, l'analyse des courbes de récession des sources et la classification des aquifères karstiques

Abstract Karst aquifers are complex hydrogeological systems that require numerous in-situ measurements of hydrological and physico-chemical parameters to characterize transfer processes from the recharge area to the karst spring. Numerous graphical, statistical or signal processing methods have been developed for decades to interpret these measurements, but there is no simple and standardized tool that can be used for this purpose, which is necessary for a rigorous comparison of results between case studies. This Technical Note presents XLKarst, which has been developed to provide a simple and easy-to-use tool to process a selection of proven methods that characterize the functioning of karst systems. This tool allows (i) time series analysis based on correlation and spectral analysis and, for flow measurements, the use of other statistics and base flow separation, (ii) calculation of the cumulative distribution function to build a spring flow probability plot, and (iii) analysis of spring flow recession and expression of the results in a karst system classification scheme. These methods are first described by providing the key elements of their use and interpretation in the scientific literature. Then, an application to the Fontaine de Nîmes karst system (southern France) is used to highlight the complementarity of the methods proposed by XLKarst to describe the hydrodynamic behavior of a karst system based on daily data of rainfall and discharge over 22 years.