Zhiqiang Li1 , Qing Zhang 1,2,3, Yuechao Chen 1 , Yangsen Yuan 2,3 , Zhentao Shi4,5
1.School of Resources and Environment, Henan Polytechnic University; 2.Henan Second Geological and Mineral Survey Institute Co., Ltd. 3.Yukuang International Mining Guinea Limited Company, Conakry, Guinea; 4.Changsha Nuclear Industry Engineering Survey Institute Co., Ltd. 5.Guangdong Tianji Construction Development Co., Ltd.
Abstract：
Unlike human activities and other factors, earthquakes often cause rapid and drastic changes in land use. Therefore, in the teaching and research of disciplines such as geography, geology, and hydrology, it is important to keep up with the times and increase numerical simulation methods to study how hydrological processes in watersheds change after earthquakes cause changes in land use. The 2018 Hokkaido Eastern Iburi Earthquake and its landslides are the main factors of land use change in the Atsuma River Basin in recent years. This study focus on the land use change before and after the 2018 Hokkaido Eastern Iburi Earthquake and studying its impact on runoff and sediment transport in the Atsuma River basin. By analyzing the land use maps of the Atsuma River basin in 2015 and 2020 and the slope collapse, sediment accumulation area after the earthquake, using the Soil and Water Assessment Tool (SWAT) model to accurately simulate the daily/monthly runoff and monthly sediment transport process in the Atsuma River basin before and after the earthquake. Finding that the earthquake and landslide transformed nearly 10 percent of the forest land into bare land in the basin. The simulation results show that the daily/monthly runoff simulation results simulated using the 2020 land use data are all slightly higher than those using the 2015 land use data, and the monthly sediment transport after the earthquake is significantly higher than before, the change are drastic. Which indicating that with the decrease of forest land, and the increase of bare land, the runoff slightly increased and the sediment transport per unit runoff increased greatly in the Atsuma River basin after the earthquake. In the future, human's active governance activities can reduce the sediment carrying amount of river basin.
Key Words：
land use change; SWAT model; runoff; sediment transport; Atsuma river basin
