Rainfall-runoff simulation in karst dominated areas based on a coupled conceptual hydrological model

Rainfall-runoff processes in the karst dominated regions are of great importance. However, not all areas in a karst-dominated river basin are covered by typical limestone and both limestone and soil cover may exist. This study proposes a coupled conceptual hydrological model for simulating the rainfall-runoff processes in karst-dominated areas. The model, named as K-XAJ, couples the traditional Xinanjiang (XAJ) model and a two reservoir-based karst model for simulating runoff in both the karst area and the non-karst area in the Lijiang River basin. Simulated results demonstrated that the proposed K-XAJ model satisfactorily simulated the rainfall-runoff processes. Compared with the traditional XAJ model, the K-XAJ model produced better forecasts. The peak flow predicted by the K-XAJ model was larger than that by the XAJ model, but the interflow routed by the K-XAJ model was significantly smaller than that by the XAJ model. The magnitude of groundwater predicted by the K-XAJ model was greater. This study thus provides a new way to simulate rainfall-runoff processes in karst areas.