Prioritization of sub-watersheds based on hydro-morphometric assessment in relation to soil erosion: A case study in Haora Drainage Basin, Tripura

• Parameters directly related to surface runoff and influences soil erosion. • DEM as well as field study helps in establishing correct correlations. • WSA and CV methods act as suitable techniques to priortize the sub-watersheds. Among all the environmental issues of the world, soil erosion is of significant concern in terms of watershed management. For proper planning and management of watersheds in terms of soil erosion, characterization and prioritization of sub-watersheds (SWs) through appropriate technique is crucial. Thus the present study focuses on prioritizing the erosion prone sub-watersheds of Haora Drainage Basin, Tripura using Hydro-Morphometric analysis. Remote sensing (RS) and geographical information system (GIS) play a vital role for providing cost-effective and accurate data of the study area. The generation of drainage networks and delineation of sub-watersheds has been done using ASTER DEM of 30 m resolution in the Arc-GIS 10.8 software. On one hand, nineteen vital morphometric parameters among the linear, areal and relief aspects in relation to soil erodibility were computed using predefined mathematical formulae and methods using the DEM and on the other hand, field surveys with necessary equipment for three consecutive water years (2021-2024) helped in evaluating six important hydrological parameters. The study area consists of nine sub-watersheds in order of SW1-SW9. The prioritization of the sub-watersheds has been done on the basis of compound value of each sub-watershed calculated by using the Preliminary Rankings of the parameters and weighted sum approach (WSA). As a result, SW5, SW7 and SW3 have been categorized into high priority and SW9 and SW1 comes under moderate priority. Four sub-watersheds namely SW6, SW4, SW8 and SW2 have been assigned low priority, suggesting that these are more sustainable than others. The study provides scientific information for decision makers toward effective soil and watershed management.