Application of fast Fourier transform in fluvial dynamics in the upper Brahmaputra valley, Assam

Abstract

Large tropical rivers such as the Brahmaputra flowing through technically active areas show highly variable bankline migration for the channel belt as a whole, as well as intra-bank, over different time windows due to different but non-uniform forcings. Fast Fourier transform (FFT) can be applied to identify frequency (cycles per unit length) content of bankline migration, to classify the wavelengths of different forcings and subsequently to compare the relative influence of different forcings for the trend analysis of bankline shift and width variation. This helps expand the interpretative scope of dynamics of river systems and plan mitigation strategies.