Surface Water Hydrology

Poster Abstract

Effect of Land Use/land Cover and Climate Changes on Surface Runoff in a Semi-humid and Semi-arid Transition Zone in Northwest China

Wednesday, January 4
10:00 AM - 5:00 PM
Location: ChuLv Hall

Water resources, which are substantially affected by land use/land cover (LULC) and climate changes, are a key limiting factor for ecosystems in arid- and semi-arid regions characterized as high vulnerable. It is crucial to assess the impact of LULC and climate changes on water resources in these areas. However, contrary results on the effect of the LULC and climate changes on runoff are reported in relatively large basins, e.g., in the Jinghe River Basin (JRB), a typical large catchment (>45000km2) located in a semi-humid and arid transition zone in the central Loess Plateau, Northwest China. In this study, we focused on quantifying both the combined and isolated impacts of LULC change and climate variability on surface runoff. It is hypothesized that under a climatic warming and drying trend, LULC change, primarily caused by intensive human activities such as the conversion of cropland to forest and grassland program (CCFGP), will alter runoff markedly in JRB. The Soil and Water Assessment Tool (SWAT) was adopted to perform the simulation. The results indicated that 1) the area of vegetation decreased by 16.23% from the 1970s to the 1990s, whereas it increased by 6.42% between the 1990s and the 2000s due to the CCFGP; 2) the air temperature has increased markedly since 1970, whereas precipitation has decreased, leading to a climatic warming and drying trend; 3) runoff increased only by 1.51 m3 s−1 between the 1970s and the 2000s due to the combined effects of LULC and climate changes; and 4) LULC and climate changes affected surface runoff differently in each decade, i.e., runoff was affected mainly by precipitation (with a contribution of 88%) and increased by 29.75 m3 s−1 between the 1970s and the 1980s; runoff decreased by 12.59 m3 s−1 between the 1980s and the 1990s, with a 56% contribution from climate change and a 44% contribution from LULC; and runoff decreased by 15.65 m3 s−1 between the 1990s and the 2000s, with a 71% contribution from LULC. Our findings reveal that large-scale LULC under the CCFGP has had an important effect on the hydrological cycle, and that the contrary results on the effect of the LULC and climate changes on runoff in relative larger basins are likely caused by uncertainty in hydrological simulation.

Jing Yin

China Institute of Water Resources and Hydropower Research

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Fan He

China Institute of Water Resources and Hydropower Research

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Yujiu Xiong

Department of Water Resource and Environments, School of Geography and Planning, Sun Yat-Sen University

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Guoyu Qiu

Shenzhen Engineering Laboratory for Water Desalinization with Renewable Energy, School of Environment and Energy, Peking University

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Effect of Land Use/land Cover and Climate Changes on Surface Runoff in a Semi-humid and Semi-arid Transition Zone in Northwest China



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