Hydrograph Analysis and Watershed Prioritization for Sustainable Development in the Thoppaiyar Sub-Basin Using GIS and Remote Sensing

Abstract

The present study focuses on a comprehensive stream hydrography analysis of the Thoppaiyar sub-basin, a significant tributary system of the Cauvery basin located in Tamil Nadu, India. The analysis integrates morphometric evaluation, hydrograph interpretation, and geospatial techniques to assess the hydrological behavior of the basin for sustainable development. The basin is characterized by dendritic to sub-dendritic drainage patterns developed over Precambrian crystalline formations, indicating minimal structural disturbance and relatively homogeneous lithology. Quantitative morphometric parameters such as stream order, drainage density, bifurcation ratio, elongation ratio, and relief characteristics were derived using GIS and remote sensing data, particularly Digital Elevation Models (DEM). Hydrograph analysis reveals that the basin exhibits a rapid hydrological response to rainfall, with a steep rising limb, short lag time, and high peak discharge, suggesting low infiltration capacity and significant surface runoff. The recession limb is relatively steep, indicating limited groundwater storage and baseflow contribution. These characteristics reflect the semi-arid climatic conditions, sparse vegetation cover, and soil properties of the basin. Spatial analysis of slope, land use/land cover, and drainage distribution further highlights areas prone to soil erosion, runoff concentration, and water scarcity. The study emphasizes the importance of integrating hydrography with watershed management practices such as artificial recharge structures, check dams, afforestation, and sustainable land use planning. The delineation of micro-watersheds enables prioritization of critical zones for intervention. The results demonstrate that scientific hydrography analysis can significantly contribute to sustainable basin development by improving water resource management, minimizing flood risks, enhancing groundwater recharge, and maintaining ecological balance. This research provides a valuable framework for regional planning and can be applied to similar semi-arid basins across India.