4.5 Summary
The morphological dynamics of the Brahmaputra River indicate its rapid planform evolution in the last four decades. The river width increased by nearly 1.7 km (mean value over the studied reach) during the period. Looking at the historical maps of Renell (1776), Wilcox (1830), and Butler (1847), we can decipher that a few centuries back Brahmaputra River was less braided with meandering stretches. It suggests that the observed morphological change of the Brahmaputra River is the continuation of the recent planform evolution of the river that can be traced back to 2-3 centuries. Such river morphological adjustments are often related to the sediment bedload, its transport, and the proportions of bedload and suspended load in a river (Schumm, 1963; Smith and Smith, 1984; Church, 2006). Taking the example of the recent massive earthquake (1950 Assam earthquake), researchers proved that high sediment release after the earthquake had affected the morphology of the Brahmaputra River (Goswami, 1985; Sarker and Thorne, 2006; Sarker et al., 2014). The rapid morphological changes in Brahmaputra River are conceivably due to high sediment flux, where seismic activities look to be a pragmatic factor.