Morphology and land use change analysis of lower Padma River floodplain of Bangladesh.

Abstract

Bangladesh, the largest delta in the world, is situated over the flow of more than 700 rivers. The Ganges is a transboundary river, and it takes the Padma after meeting Jamuna near Aricha. The Padma River's morphology and hydraulic parameters are so dynamic that it erodes a large portion of land every year. However, the situation of erosion has been very threatening since 2014 which is almost the same period when the construction of the Padma Bridge started. Our Study on the erosion-accretion rate and bar dynamics of the selected reach of Padma River shows that the downstream right bank of this river lost around 134.85 sq. km of land between 2003 and 2021. The total bar area has also increased to 76.8%. Land use land classification (LULC) analysis was done for the years 2003, 2009, 2015, and 2021 to predict how the river might act in the future. For this prediction, artificial neural network (ANN) system has been used, and the predicted land use map was generated for 2027. The current kappa validation was 0.869, and the accuracy of the prediction was 87.05%. This study aims at analyzing the current morphological condition and its connection to the construction of the Padma Bridge and also predicts how the lower Padma River might act in near future. According to the study findings, in absence of prompt and appropriate measures, this country is highly susceptible to experiencing catastrophic consequences.