The nature and controls on downstream change of channel sediment along the Shiyang River, Northwest China

The grain size composition and distribution of river sediments are important for understanding regional geomorphological evolution, source-sink processes drainage ecology. Shiyang River basin, an inland system in northwestern China, provides environmental context within which to investigate the relationship between sediment particle factors. Based on analysis characteristics modern riverbed sediments, basin parameters lithology, it is found that median (Md) shows a decrease trend from upstream downstream basin. One tributaries named Jinta obvious fining (exponentially decreasing) Md, related old development stages relatively homogeneous lithology Md along Xiying River, another tributary, complex fluctuations, might be affected by tectonically active, young geomorphic stage, confluence tributaries. gravel-sand transition zone occurs plain section about 28 km out mountain, combination features, morphology hydraulic sorting.