Soil and Water Conservation Impacts Study by biophysically based eco-hydrological model in Jinghe River Basin, China

The Jinghe River Basin is a large basin in the Loess Plateau, which is in the wind and water erosion transitional belt of China's Loess Plateau. Many soil and water conservation measurements have been applied in this basin to decrease soil erosion and recover vegetation. However, these measurements impact the hydrological process and streamflow. This paper presents an application of a biophysically based eco-hydrological model -The Regional Hydro-Ecological Simulation System (RHESSys) in the Jinghe River Basin to study the impacts of soil and water conservation measurements including vegetation construction and engineering construction. This is the first time that the model is applied in a large basin (> 10000km(2)) and some adjustments of the model (such as stream routing, reservoir operation and soil and water conservation engineering) were conducted to fit for large basin application. Field observation data, literature values and remote sensing data were used to calibrate and verify the model's parameters, and the verification showed that the model can represent the eco-hydrological dynamic processes in this basin. Three scenarios were set and simulated, which results were compared to quantify the vegetation construction and soil and water conservation engineering impacts on streamflow. The results show that the soil and conservation decrease annual streamflow by 8.36% (0.122 billion m(3)), and the largest decrease happened in 2000s. The soil and water conservation engineering has larger impacts than vegetation construction.