title: Assessing the effects of changes in land use and climate on runoff and sediment yields from a watershed in the Loess Plateau of China.
abstract: The changes in runoff and sediment load in the Loess Plateau of China have received considerable attention owing to their dramatic decline during recent decades. In this paper, the impacts of land-use and climate changes on water and sediment yields in the Huangfuchuan River basin (HFCRB) of the Loess Plateau are investigated by combined usage of statistical tests, hydrological modeling, and land-use maps. The temporal trends and abrupt changes in runoff and sediment loads during 1954-2012 are detected by using non-parametric Mann-Kendall and Pettitt tests. The land-use changes between 1980 and 2005 are determined by using transition matrix analysis, and the effects of land-use and climate changes on water and sediment yields are assessed by using the Soil and Water Assessment Tool (SWAT) hydrological model and four scenarios, respectively. The results show significant decreasing trends in both annual runoff and sediment loads, whereas slightly decreasing and significantly increasing trends are detected for annual precipitation and air temperature, respectively. 1984 is identified as the dividing year of the study period. The land-use changes between 1980 and 2005 show significant effects of the Grain for Green Project in China. Both land-use change and climate change have greater impact on the reduction of sediment yield than that of water. Water and sediment yields in the upstream region show more significant decreases than those in the downstream region under different effects. The results obtained in this study can provide useful information for water resource planning and management as well as soil and water conservation in the Loess Plateau region.
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, PR China; Joint Center for Global Change Studies, Beijing 100875, PR China.
authors.forename: Depeng
authors.initials: D
authors.lastname: Zuo
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, PR China; Joint Center for Global Change Studies, Beijing 100875, PR China. Electronic address: zongxuexu@vip.sina.com.
authors.forename: Zongxue
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Yellow River Institute of Hydraulic Research, Zhengzhou, Henan 450003, PR China.
authors.forename: Wenyi
authors.initials: W
authors.lastname: Yao
authors.affiliation: Yellow River Institute of Hydrology and Water Resources, Zhengzhou, Henan 450004, PR China.
authors.forename: Shuangyan
authors.initials: S
authors.lastname: Jin
authors.affiliation: Yellow River Institute of Hydraulic Research, Zhengzhou, Henan 450003, PR China.
authors.forename: Peiqing
authors.initials: P
authors.lastname: Xiao
authors.affiliation: Yellow River Institute of Hydraulic Research, Zhengzhou, Henan 450003, PR China.
authors.forename: Dachuan
authors.initials: D
authors.lastname: Ran
keywords: Land use; Loess Plateau; Runoff; Sediment load; Statistical analysis; Swat