Assessing the Controls of Landscape Evolution in the Cauvery River Basin, South India, through Watershed Scale Morphometric Indices

ABSTRACT On a dynamic spatial-temporal scale, the complex interactions between tectonics, climate, and lithology influence and control landscape evolution. Quantitative morphometric parameters provide insights into these influences and resultant spatiotemporal variations of controls within drainage basins. This study analysed 17 tributary basins and the delta of the Cauvery River using Survey of India topographic sheets. This work assessed landscape controls at a micro-watershed scale by digitising 205,629 streams from 154 topographic sheets and delineating 2,233 third-order watersheds for detailed spatial analysis. Although the study of morphometric indices is standard, their application at this scale in the Cauvery Basin is novel, bringing to light subtle information on basin evolution. Morphometric indices, longitudinal profiles, knickpoint distributions, drainage patterns, and extensive fieldwork collectively revealed tectonic and structural control on drainage development in the middle part of the Cauvery Basin. Notably, ongoing uplift is evidenced in the Bhavani-Suvarnavathi-Palar-Chinnar and parts of Amaravathi and Aiyaru sub-basins, while Lakshmanthirtha and Kudamarutti sub-basins exhibit tectonic dormancy. Integrating high-resolution morphometric data with field observations offers a comprehensive understanding of spatial heterogeneity in tectonic-climatic-lithological controls, Precambrian basement reactivation and enhances our understanding of the regional landscape evolutionary history.