Eco-hydrological simulation of soil and water conservation in the Jinghe River Basin in the Loess Plateau, China

Abstract

On the Loess Plateau of China are highly erodible soil and fragile ecosystem. In order to alleviate soil and water loss, and to restore the ecosystem, some soil and water conservation measures were taken in this region. In this study, we developed a distributed eco-hydrological model to simulate and evaluate the eco-hydrological impacts of soil and water conservation. The model coupled a vegetation ecosystem model, namely, BIOME-BioGeoChemical Cycles (BIOME-BGC) and a distributed hydrological model, namely, Water and Energy transfer Processes in Large river basins (WEP-L). BIOME-BGC updates the vegetation parameters of WEP-L on a daily time step, and WEP-L provides hydro-meteorological data to BIOME-BGC. The simulation was conducted in the Jinghe River Basin (45421 km2) on the Loess Plateau. The model validation shows that the simulated results match well with the field observation data and literature values of Leaf Area Index (LAI), Net Primary Production (NPP) of vegetation and river discharge. To evaluate eco-hydrological response of future water and soil conservation measures in the Jinghe River Basin, five scenarios were set based on land use changes and scenario simulations were performed using the eco-hydrological model. The results show that with the influences of water and conservation management, the average annual and flood season discharge may decrease as the vegetation evapotranspiration (ET) increases. It will bring more challenges to the water resources management in the basin than ever before. The annually-average NPP and Net Ecosystem Production (NEP) may increase, leading to more carbon sinks in the basin, which benefits to the reduction of greenhouse gas.