Geomorphological changes of river Surma due to climate change

Globally, Bangladesh is one of the most climate-vulnerable countries due to its low-lying topography, high population density, and unique geographic location. It is well-established that the influences of changing climate are inducing variability in the temperature and rainfall patterns of the country, which in turn impacts the hydrological conditions of the major river systems. Surma river, a transboundary river that flows through Sylhet Division in Bangladesh, drains one of the world’s heaviest rainfall areas—Cherrapunji of Meghalaya in India. The present study aims to investigate the impact of climate change on the Surma river’s morphological features such as depth, width, bank-line shifting, etc. by employing a bibliometric assessment of relevant literature and data analysis from USGS and NASA. The findings indicate that between 2016 and 2021, the percentage of water bodies in the upstream and downstream portions of Surma river decreased from 18.3% and 31.7% to 8.2% and 24.1%, respectively, impacting the rate of groundwater recharge. In addition, increased rainfall, erosion, and sediment deposition near the riverbank caused the river’s retaining capacity to decrease and consequently, resulting in frequent flooding events. Moreover, the effects of climate change on the Surma river are impacting the fisheries and agricultural activities of the surrounding area. It is anticipated that the findings of the present study will assist in developing an effective water resource management strategy to mitigate impacts of climatic change-induced natural disasters, such as floods and other hydrologic events in this region.