Dry Means Green—Using ALS LiDAR DEM to Determine the Geomorphological Reaction of a Large, Untrained, European River to Summer Drought (the Vistula River, Warsaw, Poland)

Using ALS LiDAR DEM, we study the geomorphology and geoecology of fluvial islands in the channel of braided river, which was affected by summer drought. We analyze hydrological data: river stages from the adjacent gauging station with telemetric system. On the basis of DoD method, we analyze the dynamics of geomorphological processes in two periods: 2019 to 2020 and 2020 to 2022. Bank erosion is analyzed on the basis of difference between DTM. Bank erosion reduces the area of riverine islands. The difference of CHM reveals a process of succession of riparian vegetation (mostly the white willow–<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Salix alba</i> L.) on sandbars. The riparian succession makes these landforms anchored by newly developed shrubs and trees, what induces accretion of sandbars. The sandbars therefore transform into riverine islands.