Evaluation of Morphometric Analysis of Sub-Basins of Narmada River using Geo-Spatial Technology and their Relation to the Geological Setting

ABSTRACT Morphometric studies uncover crucial geological and hydrological characteristics of the watershed, which help in effective management of water resources and sustainable utilisation. This study conducts a comprehensive morphometric analysis of the five key Narmada River basin (NRB) sub-basins, specifically: (NSB1-Tudar sub-basin; NSB2-Banjar sub-basin; NSB3-Hiranr sub-basin; NSB4-Bherr sub-basin; NSB5-Tawa sub-basin), which serve as substantive tributaries of the NRB, India. The primary aim was to understand the basin’s hydrological and geomorphological characteristics of the basin, using Geo-Spatial Technology (GST) and SRTM 90m data, with a focus on linear, aerial, and relief aspects and their lithological associations. Our findings revealed that sub-basin-4 (NSB-4) comprises the highest 6th order streams, while the remaining are 5th order streams. The drainage texture is categorised as coarse grain texture, in which all values in the study area are < 2, indicating a rugged and active landscape dominated by high erosion, surface runoff and low infiltration. The elongation ratio values (0.13 and 0.14) reveal an elongated nature of the sub-basins. A high stream frequency and irregular, elongated basin shape indicate the potential for rapid runoff and erosion susceptibility. Furthermore, the basin’s low bifurcation ratio suggests a dendritic drainage pattern, while the elongated stream segments signify areas prone to overland flow. Infiltration capacity varies significantly, with basaltic sub-basins showing 42% higher rates than granitic-gneiss and limestone sub-basins. Ruggedness also differs, with granitic-gneiss sub-basins being 66% more rugged. Other parameters like circulatory ratio, elongation ratio, and drainage texture show smaller variations, with limestone shale rock types having a slightly higher circulatory ratio (9 and 5% higher than basalt and granite-gneiss, respectively). These results have important implications for landuse planning, flood management, and environmental conservation efforts in this river basin. By enhancing our understanding of the basin’s morphometric characteristics, this analysis provides valuable insights into its hydrological behaviour and geomorphic evolution.