Abstract
The research presented in this paper is an attempt to characterise morphological processes that take place in the middle Vistula River channel. The research considered different cartographical materials (maps, aerial photographs) from 1959 to 2020. The chosen fragments of the middle reach of the Vistula River were analysed for changes in the channel bar size and changes in the channel width. It was stated that changes in the river width are the reason for the emergence of channel bars. The bars that were examined are stable, and they are located at a certain distance from the river narrowing. At some of the locations, the erosion-sedimentation processes are still taking place. A methodology for river channel deformation assessment based on a comparison of aerial photographs was proposed in this research. This methodology is unique and can be successfully utilised for river channel assessment. The results provide important knowledge about the characteristics of channel processes in the middle Vistula River reach that can be used for future river management.