Fig. 1

Map showing the Karamana and Vamanapuram river basins and their tributaries in southwestern India. The map was created using the Bhuvan 2D platform and refined using ArcGIS software (version 10.7). The background includes the Digital Elevation Model (DEM) of the watershed, with locations of water, rock, and weathered profile sampling, along with dams and artificial canals. DEM data were obtained from the Shuttle Radar Topography Mission (SRTM) database (https://dwtkns.com/srtm30m/) and processed with ArcGIS (https://resources.arcgis.com/en/help/main/10.7/).