Geospatial and NDBI approaches for the Musi River basin morphometric studies in the metropolitan urban Cities of India

Abstract

This study aims to advance the understanding of hydrological dynamics and geomorphological characteristics of the Musi River Basin through the novel application of Remote Sensing (RS) and Geographical Information System (GIS)-based morphometric analysis across three delineated sub-basins (SB-1, SB-2, SB-3). By examining parameters such as stream order, bifurcation ratio, drainage density, and land cover changes using the Normalized Difference Built-up Index (NDBI), the study provides a comprehensive overview of the basin’s surface hydrology and urbanization impact. Key findings reveal low surface runoff and high permeability, supported by low drainage density (0.64 km/km2) and stream frequency (0.48 streams/km2). SB-3′s elevated bifurcation ratio (5.0) highlights substantial structural control, contrasting with moderate bifurcation ratios in SB-1 and SB-2. Hypsometric analysis indicates a transition from youthful to mature phases across the basin, with SB-3′s ruggedness values reflecting moderate erosion. A 21-year land cover analysis (2000–2021) based on NDBI highlights notable changes: water bodies (2.67 %), moisture soils (5.04 %), built-up lands (3.10 %), and vegetation (2.74 %) have all increased, while fallow lands/wastelands decreased by 13.54 %. The urban expansion, driven by rapid population growth, underscores pressing ecosystem challenges. Validation of the land cover analysis yielded a robust AUC score of 0.840, affirming the reliability of the NDBI-based classification. This research showcases the efficacy of DEM-based morphometric methods for precise catchment delineation and stream order classification, providing critical insights for effective water resource management and watershed planning in the Musi River Basin.