Spatiotemporal dynamics of river channel patterns during the last 400 years in Central Germany

The Elster-Pleiße floodplain south of Leipzig has undergone significant hydromorphological changes over the past few centuries, influenced by both natural processes and anthropogenic interventions (e.g. characterized by the repurposing of former river courses into mill races and other engineered water-management channels). This study employs selected mapping of fluvial-geomorphological features based on a LiDAR DTM (Light Detection and Ranging Digital Terrain Model; 1 x 1 m resolution) and old maps analyses to reconstruct past river dynamics and identify shifts in channel morphology. Geomorphological features, such as oxbows, ridge-and-swale point bar structures, crevasse splays and levees reveal an earlier, more dynamic floodplain characterized by meandering and anabranching channels, which transitioned into a system of stabilized, largely immobile watercourses. Comparative analyses of old maps spanning from the 16th to the 20th century indicate a gradual reduction in river sinuosity and lateral migration, coinciding with increasing human modifications such as mill races, timber rafting canals, and flood protection measures. Key transformations include the straightening of channels, floodplain aggradation, and the impact of open-cast lignite mining in recent centuries. The study highlights the complex interplay of sedimentary processes and anthropogenic activities in shaping the floodplain's evolution. This combined approach allows for a detailed examination of the relative chronology of changes and helps identify topographic legacies left by dynamic floodplain systems, enhancing our understanding of the evolution of these landscapes. Understanding these long-term dynamics provides crucial insights for contemporary river restoration and flood management strategies.