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.