Development of new Ecological Susceptibility Index (ESI) for monitoring ecological risk of river corridor using F-AHP and AHP and its application on the Mayurakshi river of Eastern India

Abstract

Human interventions have largely influenced morphological, ecological and aesthetic quality of many rivers across the world. Scientists and researchers have developed several indices to measure ecological quality, ecological health and pollution status using physical, biological and chemical parameters. But the physical biological and chemical status of rivers are controlled by the terrain over which it is flowing, land use and land cover pattern along river belts and different form of human interventions within channel. Therefore, the present research made a painstaking attempt to develop a new Ecological Susceptibility Index (ESI) of the Mayurakshi river of Eastern India and its adjacent corridors (200-m buffer on each side of river bank) through scientific analysis of geomorphological, ecological, aesthetic and anthropogenic parameters. These includes, channel planform, geomorphology of river corridor, NDVI (Normalized Difference Vegetation Index), NDTI (Normalized Difference Turbidity Index), land use land cover, human encroachment, distance from road and proximity to mining plots. The Fuzzy- Analytical Hierarchy Process (F-AHP) and Analytical Hierarchy Process (AHP) methods were implied to ascertain the priority-based criteria and sub-criteria weights of each factor. In doing so, we have identified higher relative weights for anthropogenic indicators than other factors. Finally, prioritized weights of each aspect were ensembled together to prepare ESI. Validation results obtained from ROC (Receiver Operating Characteristics) curve and Kappa statistics show that the ensemble of F-AHP and AHP are highly efficient in predicting eco-geomorphological and aesthetic quality of river and adjacent riparian corridor. Finally, the investigation reveals that the lower-middle segments of the Mayurakshi river are highly susceptible to ecological changes as compared to other sectors.