Analysis the Land Cover and Land Use (LULC) Change by Unsupervised Classification and the NDVI Method Around Tongi Khal, Dhaka, Bangladesh.

Abstract

Urban and industrial development, along with anthropogenic activities, lead to numerous threats to Bangladesh's water bodies. Over the years, Tongi Khal has been identified as being in a threatened condition due to these activities. This research presents dynamic changes in land use and land cover (LULC) and the condition of Tongi Khal by using GIS and remote sensing techniques.
The LULC changes in the study area are illustrated using Landsat satellite images from 1990, 2000, 2010, 2015, 2020, and 2025 obtained through unsupervised classification and the Normalized Difference Vegetation Index (NDVI) method in ArcGIS 10.3. From 1990 to 2025, the LULC classification in the study area shows a reduction in water bodies and vegetation from 1990 to 2015, followed by an increase in vegetation in 2020 due to COVID19. In 2025, due to excessive industrial development, construction projects, canal infilling, and urban expansion, the waterbody was reduced, resulting in deterioration of the environmental conditions of Tongi Khal. Extensive urban development has led to the conversion of trees into grassland, bare land, and housing to accommodate population growth from 1990 to 2025.
This study will enhance understanding of effective measures to control excessive anthropogenic activities and canal infilling, and to maintain water quantity and support natural restoration processes, such as at Tongi Khal. It will also contribute to future urban land-use planning and river management to tackle the ongoing, alarming pollution and unplanned industrialization.