Influence of the conduit geometric structure on the estimation accuracy for the karstic water storage variation

Abstract

Karst conduits are specialized groundwater flow pathways, and karst water resources are significantly influenced by conduit geometric characteristics due to uneven interactions between groundwater and karst aquifer media. Therefore, the objective of this study was to examine how variations in the geometric structure of karst conduits affect the estimation accuracy of karstic water storage variation (KWSV) by using a numerical modelling approach. By analysing spring flow recession hydrographs following rainfall events in matrix–conduit coupled karst systems, this study demonstrated that conduits with greater diameter, roughness coefficient, tortuosity and conduit conductance values could lead to systematic underestimations of the KWSV due to rapid flow responses and accelerated recession behaviour. However, the variation patterns of the KWSV variables vary among different conduit structural parameters. These findings highlight the importance of incorporating detailed geometric data into karst models to improve the predictive accuracy of the KWSV and gain greater insights into the role of the conduit geometric structure in controlling groundwater flow behaviour, particularly in regions with complex karst networks.