Sub-watershed prioritization in Greater Andaman through morphometric insights

Abstract Water resource management is crucial for addressing water scarcity and climate change issues worldwide, driven by population growth. Watershed prioritization has gained significant importance in water resource management. Morphometric analysis serves as a vibrant tool for quantitatively interpreting landforms and drainage characteristics across varied terrains. The present work emphasized the prioritization of soil and groundwater conservation in eight islands of the Greater Andaman districts. This study prioritized sub-watersheds for the study region using Quantum Soil and Water Assessment Tool (QSWAT), in conjunction with a Digital Elevation Model (DEM) and Geographic Information System (GIS), which facilitated the evaluation of linear, areal, and relief morphometric parameters within relatively understudied micro-watersheds of the study area. A comprehensive morphometric assessment was carried out up to the sixth stream order, revealing that the islands’ drainage networks predominantly exhibit dendritic, trellis, and parallel patterns. The quantitative measurements of twenty-three morphometric parameters were analyzed for the prioritized sub-watersheds. The Land Use Land Cover (LULC) were utilized to characterize the features of the sub-watershed. Further, Hypsometric Integral (HI) values showed moderate maturity, and the entire study result was categorized into three priority classes—low, medium, and high sub-watersheds. Among the high-priority sub-watersheds, 15 have been identified as requiring immediate attention for conservation and management interventions. High-priority coastal sub-watersheds require careful monitoring to ensure sustainable sand mining and recharge planning, thereby preserving sediment balance and groundwater sustainability. The study provides insights for evidence-based watershed management, land-use planning, erosion control, and sustainable groundwater use in the Andaman Islands.