Assessing ecological vulnerability in the Kulsi River Basin, Assam using an MCDM-based analytical hierarchical approach

Abstract

The Kulsi River basin, situated in the South Kamrup district of Assam, India, is noted for its rich fish diversity and significant deposits of Pre-Cambrian quality sand in its headstreams. These deposits gradually make their way downstream, acting as a catalyst for local livelihoods. However, the intricate ecosystem fostered by the Kulsi River is under significant ecological threat due to urbanization, population growth, and associated environmental stressors such as rampant sand mining, deforestation, and soil erosion. These changes pose a risk to the basin's ecological sustainability, increasing its vulnerability. This study employs the Analytical Hierarchical Process (AHP), a GIS-based multi-criteria decision analysis method, to assess and monitor the basin's ecological vulnerability. It seeks sustainable methods to rejuvenate ecological sustainability in the basin. Criteria such as slope, C factor, stream density, proximity to roads, soil erosion, literacy rate, soil erodibility factor, and rainfall were analyzed. The findings reveal varied vulnerability across the Kulsi River basin, with 6.24% of the area classified as extremely vulnerable, 25.56% as highly vulnerable, 24.56% as moderately vulnerable, 32.67% as low vulnerable, and 10.94% as non-vulnerable. Highly vulnerable zones are notably in newly developed suburban areas adjacent to national highways. However, non-vulnerable zones are primarily in the upper river course and its surrounding regions in the southern direction. The findings highlight the urgent need for targeted mitigation strategies to address the adverse effects of human activities and natural processes on the basin's ecological integrity. This study maps the vulnerability of the Kulsi River basin. It provides valuable insights into sustainable management and hazard mitigation. The study highlights the link between human activity, ecological sustainability, and geomorphological hazards.