Study on the influence of revetment on the evolution law of river channel morphology in the wandering section of Tarim river

The fluvial geomorphology of wandering rivers exhibits distinctive characteristics that distinguish them from other river types. Understanding the mechanisms underlying water-sediment dynamics and bank protection density in the morphological adjustment processes of wandering rivers is of considerable scientific and practical importance. Utilizing multi-temporal remote sensing imagery spanning from 2013 to 2023, this study systematically quantifies the morphological characteristics of a 65-km reach extending from Sanyuankou to Tarim River's Third Bridge through comprehensive extraction of key geomorphological parameters along the central sandbank line. The investigation employs an integrated approach combining hydrological datasets to elucidate the quantitative relationships governing thalweg migration patterns in successive meander bends under constrained boundary conditions. The analytical results demonstrate that the asymmetric distribution of bank protection density, characterized by relatively low values on both left and right banks during 2013-2017, significantly influenced fluvial geomorphological processes, resulting in irregular variations in the sandbar index ([Formula: see text]) and extensive thalweg migration. Quantitative analysis revealed a significant reduction in the sandbar index ([Formula: see text]) from 4.31 during 2013-2017 to 2.80 in the subsequent period (2018-2022), representing a 35% decrease. With the increase in riparian density, the magnitude of the thalweg oscillations was most substantially franked in typical continuous bend reaches compared to other channel reaches. An empirical formula was developed to predict the thalweg swing width in successive river bends under fixed boundary conditions, taking into account the interplay between water-sediment dynamics and bend revetment parameters. The formula's validity was confirmed through empirical testing, which demonstrated a strong correlation between the computed results and the observed data. The research results have important reference significance for the prediction of river regime in continuous bends of wandering rivers.