Bankline Shifting and Morphological Change Detection of Teesta River, Bangladesh: a GIS and Remote Sensing Based Case Study

Abstract

This study investigated relations between channel shifting, water level variation, erosion, and accretion of the Teesta River in Bangladesh. Landsat TM satellite images (resolution 30m) for the years 1990, 2000, 2010, and 2020 were used to delineate the bankline migration. The hydrological water level data (1990-2020) collected from the Bangladesh Water Development Board (BWDB) was used for water level analysis. Geographic Information System (GIS) and Remote Sensing (RS) techniques were used to analyze the spatial movement of the river bankline. Exploratory data analysis techniques were used for trend analysis of the hydrological parameters. In contrast with these, river width, erosion, and accretion area were estimated through satellite images by using different tools in ArcGIS Pro and Microsoft Excel. Results show that there is a large effect of the water level variability on erosion and accretion processes. These processes act as a function of bankline movement and indicate the dynamic nature of channel shifting. River in different cross-sections become narrow and sometimes expand in relation to erosion and accretion level at the different cross-sections. Findings demonstrate that erosion and accretion occurred all the years which change the river area and river channel migration.