Rainfall events‐spring flow relationship and karst flow component analysis in a conduit‐matrix coupled system

Abstract

AbstractKarst aquifers have complex structures and high heterogeneity, making it difficult to describe their hydrogeological characteristics. An essential tool for comprehending karst hydrogeology and identifying the hydraulic characteristics of the karst system is a quantitative analysis of the recession process of the karst spring hydrograph. The recession process of the spring hydrograph following a rainfall event can be utilized to assess the internal structure of the karst system as it relates to the karst aquifer's response to rainfall events. In this study, a laboratory physical experiment model is built based on typical karst hydrogeological circumstances, and a corresponding combined discrete‐continuum (CDC) numerical model is established, coupling conduit and matrix. The primary goal of this paper is to investigate how the recession process of the spring hydrograph responds to various rainfall events. Different rainfall intensities with the same rainfall duration and various rainfall intensities with the same rain amount are examples of rainfall patterns. The simulation results showed that the pattern of rainfall events affects the recession process of the spring hydrograph, and the recession coefficient of the corresponding recession stage, the proportion of water volume released by conduit and matrix with the different rainfall patterns are calculated and analysed, and the impact of rainfall events on the recession coefficient of spring hydrograph and the spring water composition has been explored. The research results can provide a reference and basis for the management of water resources in karst areas.