Quantitative Multiyear Assessment of Flood Impact on Land Use and Land Cover in Sylhet Region, Bangladesh: Insights from Sentinel Imageries

Abstract The northeastern Sylhet region of Bangladesh has faced severe flooding, leading to tragic consequences such as loss of life, displacement, and economic challenges. This study evaluates the impact of flooding on various land uses in the region from 2018 to 2022. Flood-affected areas were identified using Sentinel-1 SAR images in Google Earth Engine (GEE), and land use was analyzed with the Dynamic World dataset of Sentinel-2 images. The study found that cropland has been significantly impacted, with two-thirds affected by floods from 2018 to 2022, and 84% in 2023, causing economic hardship. In 2018, 27% of vegetation coverage was affected, decreasing in subsequent years but rising to 30% during the 2022 flood. In 2018, about 47.83 km 2 of built-up area was impacted, increasing to 128.135 km 2 in 2022. The total affected population (TAP) in Sylhet district increased from 27% in 2021 to 43% in 2022, while Sunamganj exhibited the highest vulnerability, with TAP rising from 65% in 2021 to 74% in 2022. These findings highlight the increasing severity of flood events, likely driven by climate change and inadequate infrastructure, and emphasize the urgent need for integrated flood management strategies to protect the population and environment in Sylhet.