Spatiotemporal dynamics of river channel patterns during the last 400 years south of Leipzig, Germany

Abstract. 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 Light Detection and Ranging Digital Terrain Model (LiDAR DTM; 1×1 m resolution) and the analysis of old maps to reconstruct past river dynamics and identify changes 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 the 16th to 20th centuries 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. The major transformations date back to at least the late 16th century and may be even earlier in origin. Key drivers 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 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.