Prioritising tropical river sub-basins using a geospatial sediment export index for aquatic ecosystem management

Land use and land cover (LULC) changes are closely associated with accelerated soil erosion and sediment transfer to stream networks, contributing to soil fertility loss and degradation of hydrological and aquatic systems. The InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) model was used to spatially estimate soil loss, sediment export and sediment retention across sub-basins of Godavari River. The model, suitable for data-scarce basins, was evaluated using available observed data, demonstrating satisfactory basin-scale performance (R2 = 0.83; Percent bias within ± 25%). Among the sub-basins, Indravati (11.97–8.56 MMT/yr), Wainganga (8.56–7.67 MMT/yr), Sabari (6.72–6.70 MMT/yr) and Penganga (4.76–4.28 MMT/yr) consistently exhibited the highest sediment load estimates during 2011–12 and 2021–22. Deciduous forests showed the highest modelled sediment retention potential, while cropland provided a secondary contribution to on-site sediment retention. A significant reduction in sediment export yield was observed in Kinnerasani (− 61.57%), Indravati (− 26.68%) and Wainganga (− 10.41%), whereas increases were observed in Manair (+ 54.87%), Pravara (+ 4.50%) and Kaddam (+ 2.05%). Most sub-basins were classified under moderately severe to severe erosion categories. In rainfed rivers of peninsular India, sediment export patterns were strongly associated with monsoon rainfall variability and concentration. This study evaluated sediment dynamics across 12 sub-basins of the Godavari River using a novel ‘precipitation concentration index-adjusted sediment export yield index’ (PCI adjusted SEYI). By integrating rainfall concentration patterns with sediment export estimates and precipitation-scaled soil tolerance limits, the index enables improved comparative prioritisation of tributaries for aquatic ecosystem management. Positive PCI-adjusted SEYI values in Pravara, Indravati and Sabari (2011–12) and Pravara and Sabari (2021–22), identify these sub-basins as priority areas for targeted soil and water conservation measures. The findings provide a practical framework for sub-basin-level sediment management and policy support in monsoon-dominated river basins.