Simulation Analysis of Runoff and Sediment Yield under the Change of Land-Use Type: A Case Study of the Upper Jianjiang River Basin, China

In order to study the impact of changes in regional land-use types on regional runoff and sediment yield, this paper takes the upper reaches of the Jianjiang River as an example. It uses the SWAT hydrological model to simulate runoff and sediment yield in this area. Based on the land-use data of 2005 and 2018, the runoff and sediment yield effects of different land-use types in the study area and its sub-basins were analyzed. The results show that: (1) The constructed SWAT model has a good simulation effect on runoff and sediment yield for the study area. (2) The most sensitive parameter of runoff is Initial SCS CN II Value (CN2), and the most sensitive parameter of sediment is USLE equation support practice factor (USLE_P). Compared with runoff, sediment yield is more sensitive to the change of land-use type. (3) The simulation analysis results of runoff and sediment yield in each subbasin show that, under other conditions being the same, forest land has an obvious effect on water and sediment reduction compared with other land-use types, followed by grass land. The cultivated land has obvious effect of increasing water and sediment, and the urban and rural residential land also has obvious effect of increasing sediment. The corresponding solutions for different land-use types have a certain reference significance for the basin???s water and soil conservation planning.