Agricultural land use doubled sediment loads in western China’s rivers

Abstract

Abstract Land use changes, such as deforestation and agricultural expansion, increase soil erosion on the scale of hillslopes and small drainage basins. However, the effects of these changes on the sediment load in rivers is poorly quantified, with a few studies scattered globally, and only 10 data points in the world’s most populous nation, China. At 20 different sites in western China, we compare contemporary fluvial sediment yield data collected daily over 4 to 26 years between 1945 and 1987 (median = 19 years) to long-term measures of sediment generation based on new isotopic measurements of in situ 10Be (beryllium-10) in river sediments. We find that median sediment yield at these sites exceeds background sediment generation rates by a factor of two (from 0.13 to 5.79 times, median 1.85 times) and that contemporary sediment yield is statistically significantly different from long-term sediment generation rates (p