The Influence of Riparian Vegetation on the Sinuosity and Lateral Stability of Meandering Channels

Abstract

Floodplains of meandering rivers are colonized with various plant species that differ in how they stabilize streambanks, modulating sinuosity evolution. Here, we compile observations of meander migration from North and South America, categorizing channels based on the riparian vegetation as cropland, forest, grassland, and rainforest. Our analysis reveals that the most stable meanders are those developed in rainforests and the reason is likely related to their established root systems and clay‐rich soils. The most unstable meanders were found in cropland areas, which is explained by the lack of vegetation cover and the frequent land disturbances associated with cultivation. Rivers in grassland and North American forest environments have intermediate migration rates. We found that meanders in grasslands have lower migration rates than those in North American forests. The reason for this may lie in the fact that grassland meanders in general have higher sinuosity, lower gradients, and layered banks.

Delayed neck cutoff in the meandering Black River of the Qinghai–Tibet plateau

“…Such differences in migration rates, and hence in neck narrowing processes and related PEPs, are likely driven by factors other than local sub-bend morphology, such as variable bank strengths (modulated, e.g., by bank materials and riparian vegetation) (Guo et al, 2021;Zhu et al, 2022) and sediment supply (Ahmed et al, 2019;Constantine et al, 2014;. Therefore, the PEPs determined in the current study likely lie near the upper bound of the PEP spectrum that characterizes highly sinuous bends in global meandering rivers.…”

“…This variation of PEPs among meandering rivers in three physiographically different regions is consistent with the difference in their migration rates, which are 1.1%, 4.0%, and 16.4% channel widths per year for the Black River, the Dane River, and the Ucayali River, respectively (Coomes et al, 2009; Guo et al, 2021; Hooke, 2007; Schwenk & Foufoula‐Georgiou, 2016). Such differences in migration rates, and hence in neck narrowing processes and related PEPs, are likely driven by factors other than local sub‐bend morphology, such as variable bank strengths (modulated, e.g., by bank materials and riparian vegetation) (Guo et al, 2021; Ielpi et al, 2022; Zhu et al, 2022) and sediment supply (Ahmed et al, 2019; Constantine et al, 2014; Ielpi & Lapotre, 2022). Therefore, the PEPs determined in the current study likely lie near the upper bound of the PEP spectrum that characterizes highly sinuous bends in global meandering rivers.…”

A Numerical Study on the Influence of Riparian Vegetation Patch on the Transportation of Suspended Sediment in a U-Bend Channel Flow

“…The lateral migration of the bending section results from the erosion of the outer bank, as well as the concurrent sedimentation in the inner bank. Many researchers believe that aquatic vegetation can improve channels' stability due to its sediment retention function and by physically strengthening the channel banks [1,[3][4][5][6][7]. Furthermore, Lelpi et al drew a significant conclusion that the anthropogenic removal of the vegetation cover in the meanders of rivers can speed up the migration rate to an order of magnitude compared to that of a vegetated meander channel [1].…”

Main Flow Migration in the Middle Yangtze River Influenced by Cascade Reservoirs: Characteristics, Controlling Factors, Trends, and Ecological Impact

“…The latter has also been noted to promote meandering and alter the meander scale in numerical simulations of river meandering. Stable meandering rivers often form in rainforests [36]. Other factors, such as human activities [37,38], differences in the composition of embankments on both banks [39][40][41][42][43], and the slope of river basins or river beds, also have an important impact on river morphology [44,45].…”