Analysing Land Use and Land Cover Dynamics (1972–2020) and Evaluating Drainage System Efficacy: A Case Study of Bangladesh Polders

In recent years, aquaculture has significantly expanded in tropical and subtropical developing countries. This expansion has led to substantial economic, food security, and environmental impacts. The southwestern region of the Ganges–Brahmaputra Basin faces severe waterlogging problems, largely because the expansion of shrimp farming affects local livelihoods. This study examines the consequences of land-use changes in the polders of Bangladesh by analysing 48 years of Landsat imagery from 1972 to 2020. This highlights a significant shift from rice cultivation to shrimp farming, leading to more waterlogged areas and fewer settlements because of poor drainage, freshwater scarcity, and increased salinity. We developed a drainage model for the polders via MIKE11 software to assess the area's drainage capacity and found that the current systems are insufficient, especially for monsoon drainage. This inadequacy encouraged a shift toward shrimp farming. Our research aims to shed light on the environmental and economic challenges of the area, promoting sustainable management of water resources. The detailed insights from this study provide a framework to develop practical and united strategies to address waterlogging issues and minimize their varied impacts on the people and economy of the region.