Application of the Compound Factor for Runoff Potential in Sub-watersheds Prioritisation Based on Quantitative Morphometric Analysis

Abstract

Abstract Accurate watershed delineation and drainage system extraction are critical tasks for the hydrological and geomorphological model. Watershed morphology evaluation is very important for flood control and recovery planning. It is beneficial for understanding the basin’s hydrology. In this study, the Rel river basin was selected, located in Gujarat, India. This study deals with the runoff potential in the semi-gauged Rel river basin depending on the detailed morphometric study. The Survey of India (SOI) topographic sheet (1:50000) and geographical information system (GIS) tools have been used for the detailed study in the evaluation of morphometric parameters. For accuracy in flat terrain, a topographic sheet has been used instead of DEM. Manually digitise the drainage from the SOI topographic sheet to precisely divide the watershed boundary; after that, the Rel basin has been divided into five sub-watersheds (SWs), namely, SW1 SW2, SW3, SW4 and SW5. Twenty-eight morphometric parameters have been calculated for each sub-watershed (SW). For runoff potential, twenty-one effective morphometric parameters have been selected based on previous studies.A compound factor (CF) model has been used for the SWs prioritisation. Twenty-one effective morphometric parameters have been considered in the CF model. The model results indicated that SW2 has a very-high runoff potential, and SW3 has a very-low runoff potential. The methodology developed and the results presented here will be critical in developing a comprehensive sub-watershed management plan. The work’s results can better understand the topography, nature of the basin, and the delineation of a suitable soil conservation site and mitigate flash floods in the flat region.