Absence of well‐developed floodplains along the lowland rivers and controls of the hydrogeomorphic conditions in the Western Ghat, India

Abstract

Lowland rivers across the world are characterized by accumulation of sediment due to a decrease in the channel slope. Despite the antiquity of the topography, the lowland part of the west-flowing rivers of Western Ghat, India is characterized by poorly developed floodplains except for the southern part of the Ghat. This poses a question of the sediment transportation and deposition capacity in these lowland rivers, which in turn governs geomorphic characteristics. In this study, we adapted a novel method to integrate hydrological model-derived discharge estimates, channel slope estimates from digital elevation models, bankfull channel width estimates from high-resolution Google Earth satellite images and field observations. We modelled the downstream distribution of total stream power (Ω), specific stream power (ω) and shear stress (τ b ) for four west-flowing river systems from different lithological and

Lowland rivers: Geomorphology, human impacts, and management

“…The dynamics of monsoonal driven rivers in India are recognized for their distinctive hydrology and morpho‐dynamics. Some ~1500 km away from the Ganga plains, along the Western Ghat, Guha et al (2022) utilize hydraulic modelling supported with field data to examine coastal draining rivers that have developed distinctive floodplain styles, which vary from ‘typical’ lowland rivers (i.e., Nanson & Croke, 1992). Moderate sized rivers along the Western Ghat have poorly developed floodplains, as most sediment bypasses the lower valley and is debauched directly into the marine environment.…”

“…The 10 special issue contributions herein reviewed concern important fundamental and applied topics within lowland river science, specifically highlighting three key themes. These include ‘natural’ river channel dynamics within settings that vary from the standard body of knowledge (Guha et al, 2022; Rogério et al, 2022; Sinha et al, 2022), geomorphic response to channel engineering (Mossa & Chen, 2022; Marteau et al, 2022; Tang et al, 2022; Wu et al, 2022), and flood basin management in response to environmental change (Keim et al, 2022; Phillips, 2022; Valentine et al, 2022). The categories are not mutually exclusive, and most contributions have linkages across multiple themes.…”