Author(s): Haili Zhu, Xiasong Hu, Zhiwei Li, Yanting Li
Linked Author(s): Haili Zhu
Keywords: source region of the Yellow River, vegetation zone, sediment composition, riparian meadow, convex bank
Abstract: Alpine meadow is generally developed well in meandering river of the Yellow River source region. Riparian vegetation plays a critical role on river stability and river bed evolution. The aim of this paper is to make a further study of riparian vegetation succession law and explicate the process of synchronous transverse migration of meandering rivers. In 2013-2016, field investigation and experimental work are conducted on quadrat survey, plant species identification, vegetation coverage degree, vegetation distribution characteristics and testing sediment grain size of point bar. The results show that from inside to outside of inner bank in study area, the riparian vegetation is generally divided into four distinct ribbon zonings or arcuation zonings: hydrophyte, hygromesophytes, mesophytes, and subshrub. The vegetation types of the four vegetation zones are abundant step by step, and the coverage degree takes the tendency of increasing. Potamogeton pectinatus L. and Halerpestes tricuspis Hand. -Mazz. are pioneer plants in convex bank, and the main dominant plants are cyperaceae Blysmus sinocompressus Tang et Wang, Kobresia tibetica Maxim and subshrub Potentilla fruticosa L. From the first vegetation zone to the fourth zone, sediment grain size progressively becomes smaller in convex bank, and the clay content increases with increasing vegetation coverage. The plants endured by flood in point bar have the effects on receding near-bank flow velocity in flood period and stabilizing the new forming point bar. The herb and subshrub in middle and outside zone of the inner bank have the effects on developing riparian meadow, entrapping sediment during flood period, stabilizing point bar, increasing soil fertility, and promoting the growth of point bar. In such a way, the velocity of forming inner bank can remain consistent with the speed of concave bank failure
Year: 2017