Riparian vegetation growing in meandering river floodplains has differing abilities to stabilize streambanks depending on the vegetation type and density, which further influences meander bend migration.  

Collaborating with Dr. Marwan Hassan from University of British Columbia (UBC) and Dr. Jeremy G. Venditti from Simon Fraser University (SFU), Prof. CHEN Dong’s team at the Institute of Geographic Sciences and Natural Resources Research (IGSNRR) of the Chinese Academy of Sciences (CAS) selected 123 meandering channels from North and South America, and categorized them into four types based on the riparian vegetation, namely grassland, cropland, forest, and rainforest (Fig. 1).  

Their analysis reveals that the most stable meanders are those developed in rainforests and the most unstable are in cropland areas. This study was published in Geophysical Research Letters in January 2022.  

The work is part of the doctoral dissertation of the first author ZHU Lekui, a graduate student supervised by Prof. CHEN. The results further indicate that, deep and strong root systems and clay-rich banks are likely reasons for the low migration rates of rainforest meanders (Fig. 1D). The high migration rate in cropland is explained by the lack of vegetation cover and the frequent land disturbance aroused by over-cultivations (Fig. 1B). Rivers in grassland (Fig. 1A) and North American forest environments (Fig. 1C) have intermediate migration rates. More stable meanders were observed in grasslands than in croplands partially due to higher sinuosity and lower gradients of the meanders as well as their layered banks (Fig. 1A).  

The influence of specific types of riparian vegetation on channel migration vegetation is complex, which remains an open question in geomorphology. The above findings can not only help geomorphologists better understand the eco-hydrographic system, but also guide hydraulic engineers in river restoration practice.  

Citation：

Zhu, L., Chen, D.*, Hassan, M. A., & Venditti, J. G. (2022). The influence of riparian vegetation on the sinuosity and lateral stability of meandering channels. Geophysical Research Letters,49, e2021GL096346. https://doi.org/10.1029/2021GL096346.

Fig. 1. Various riparian vegetation A) grassland; B) cropland; C) forest; D) rainforest (Image by CHEN Dong)