Conceptual hydrological model of corrosional hill karst watershed and its application

To mitigate the insufficiency of the traditional hydrological model in karst hydrological simulation, the Xin'anjiang Hydrological Model was modified by reconstructing a heterogeneous groundwater system with linear reservoirs and introducing the virtual area coefficient of the watershed (f) to modify non-conservative characteristics. The modified Karst Hydrological Model was applied to the Chongling River Basin, a typical corrosional hill region of southern Hunan Province, China. In addition, this study focused on dynamic changes of non-conservative characteristics based on the modified model. The results demonstrate the following:① The modified model outperformed the Xin'anjiang Model in karst hydrologic simulation (by 11.21%) especially in water balance (by 23.29%) and low water flow (by 27.64%); ② The non-conservative status of the karst watershed has duality because of the multi-directionality of the underground confluence system; ③ The area of the underground system is positively correlated with precipitation, while the variation of the area decreases with the increase of the precipitation by the constraint of underground saturation; ④ Inter-catchment water exchange exhibits time lag because of the hydration and water retention of karst.