Evaluating the influence of land-cover change on catchment hydrology through the modified Xinanjiang model

Land surface characteristics are closely related to hydrological processes. Nowadays, land-cover change induced by rapid economic development and intensive human activities tends to have significant effects on hydrology. In this paper, the potential impact of land-cover change on evapotranspiration, runoff volume, and flood events is assessed for the Hanzhong watershed in central China through the modified Xinanjiang model, i.e. the Xinanjiang vegetation-hydrology model. Numerical simulations are performed by assigning various land-cover types to the watershed. Simulation results show that afforestation in the Hanzhong watershed can raise evapotranspiration by 2.1-11.1%, reduce runoff by 1.3-7.5%, and reduce and delay flood peaks effectively. Conversion from forests to cropland, wooded grassland or grassland covers tends to reduce evapotranspiration by 3.1-22.2%, increase total runoff by 2.0-15.0%, and likely makes flood peaks increase and appear earlier.