Formation, Migration, and Morphodynamic Alteration of 50 Channel Bars in Darjeeling Himalayan Piedmont Zone, India

Channel bars are common, striking fluvio-geomorphic depositional features of alluvial rivers. The study of this article has aimed to investigate the formation, migration, and morphodynamic alteration of channel bars (n = 50) in gravel braided alluvial rivers in Darjeeling Himalayan Piedmont zone. Dynamics of micro to meso bar deposition is mainly accomplished by the channel gradient, huge upstream landslide, and variation of discharge. Multi-criteria analysis method has been used to explain the variation of principal component analysis (PCA1, PCA2, and PCA3), both monsoon to post-monsoon. Bridge scouring, empirical aggradation, and degradation values are 0.1 to 1.05 m and 200 kg m 2 s − 3 - 2500 kg m 2 s − 3 - 2500 kg m 2 s − 3 . Migration, re-generation, and degradation of the micro bars with their optimum morphology show changes during the rainy season. In the upper ( ( Δ u A ) ), middle ( ( Δ m A ) ), and lower ( ( Δ l A ) ) piedmont region, the bar dynamic area are 0.12 to 0.71, 0.12 to 2.83, and 0.10 to 5.43 km2, respectively. In total, 58% to 72% stability of the channel bars is observed in the upper piedmont region. The coefficient of determination (R²) of channel bar area and width shows positive (0.63) relation.