H102-09
HYDROLOGICAL RESPONSE TO LAND USE AND CLIMATE CHANGE IN THE UPPER AND MIDDLE YELLOW RIVER BASIN

Thursday, 10 December 2020: 17:54
Virtual
Dandan Ren1, Shuguang Liu1, Yiping Wu2 and Shuai Wang3, (1)Faculty of Life Science and Technology, and National Engineering Laboratory for Applied Technology in Forestry & Ecology in Southern China, Central South University of Forestry and Technology, Changsha, China, (2)Xi'an Jiaotong University, Department of Earth & Environmental Sciences, Xi'an, China, (3)research center for eco-environmental sciences, CAS, Beijing, China
Abstract:
Yellow River was the largest river sediment load in the world. However, annual sediment load and runoff decreasing significantly in recent decades.Studies have shown that in the past 60 years,sediment deposition decreased approximately 90%.The main driving factor affecting the hydrological cycle of the Yellow River basin is controversial due to the "ecological engineering" effect and the complexity and diversity of climate change.Therefore, simulating the ecological and hydrological process of the Yellow River Basin and understanding the mechanism affecting the variation of hydrological process,are essential for water and soil conservation, water resources utilization and economic development in arid and semi-arid regions of China.

In this study, the effects of land use and climate change on hydrologic process in the Yellow River basin were explored by utilizing statistical tests and Soil and Water Assessment Tool (SWAT).We employed the Modified Mann-Kendall (M-K) test and the nonparametric median-cased linear model method proposed by Sen to estimate the magnitude of trend. Pettitt test was used to detect a change-point of hydrological data in the Yellow River basin from 1956 to 2016.The impact of land use and climate change on hydrological was predicted by SWAT,using estimated future meteorological data to simulat hydrological process inthe future.The results revealed that SWAT model has regional adaptability problem, the soil flow and groundwater module of SWAT model cannot be well adapted to the hydrological simulation of the Yellow River Basin. However, the simulation results can be accepted.The statistical analysis indicated that the sediment load and runoff in most of mainstream stations in the Yellow River basin showed a significant downward trend (P<0.001), however,the precipitation and temperature showed an upward trend to varying degrees. The variation of Normalized Difference Vegetation Index (NDVI) showed that Grain for Green Project had a significant positive impact on the land use change in the Yellow River Basin. The effect of land use change on sediment reduction was greater than that on runoff. The research results can provide reference for water resources planning and management, as well as soil and water conservation in the Yellow River.

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