Analysis of the erosion and accretion dynamics of the teesta river: Shifting patterns from 1993 to 2023

The Teesta is one of the most dynamic river systems in Bangladesh. This study aims to investigate the erosion and accretion processes along the Teesta River in Bangladesh within a designated reach from 1993 to 2023. The bank line migration was delineated using Landsat TM and OLI satellite images taken in 1993, 2003, 2013, and 2023 with a resolution of 30 meters and WRS_PATH, WRS_ROW 138,042. Water level analysis was conducted using the hydrological water level data (1993-2023) obtained from the Bangladesh Water Development Board (BWDB). The spatial movement of the river bank line was examined using remote sensing (RS) and geographical information system (GIS) techniques. The trend analysis of the hydrological parameters was conducted using exploratory data analysis techniques. In contrast, various ArcGIS and Microsoft Excel tools were used to estimate the accretion and erosion area of Lalmonirhat from satellite images. The findings indicate that erosion and accretion processes are significantly impacted by variations in water levels. These procedures show how channel shifting is dynamic and responds to changes in the bank line. Depending on the degree of accretion and erosion at various cross-sections, the river may narrow or occasionally enlarge. The results show that accretion and erosion took place every year, changing the river area and the migration of the river channels.