Longitudinal profiling and elevation-relief analysis of the Indus

Abstract

The Indus basin-one of the largest fluvial-controlled landscapes of the world, provides a major agro-economic resource base while showcasing unique morphometry along its course. However, despite its large socio-economic relevance in South Asia, a distinct account of morphometric variations down its course still remains elusive. Here, for the first time a quantitative demarcation of the Indus basin into-upper, middle, and lower basin is proposed based on analyses of critical morphometric parameters (viz. gradient/river length ratio, elevation-relief ratio, channel width, sinuosity, and slope). Geostatistical and hydrological operations performed on digital elevation models, suggest that the highest and lowest relief sectors are tectonically more stable than the middle relief sector, inferred from a convex hypsometric curve. Elevation-relief ratio for the basin indicates tectonic stability with ~ 31% of remnant rock still in place. Cross-sectional transects also demonstrate anomalous patterns that deviate from predictive characteristics of youthful, mature, and senile stages of river development. All parameters are spatially coalesced to provide a first-ever holistic morphometric account of the Indus basin while describing fine-scale planform variations of the spectacular dynamics of this enormous river basin.