Bedrock steps in the Vistula River channel in the Sandomierz Basin – genesis, evolution, and geotourism potential

The article documents the origins and present-day evolution of the bedrock steps in the Vistula River near Nowe Brzesko. This section of the river is unique, located outside the Carpathians and designated as a geosite. The analyses were based on a series of aerial photographs and orthophotomaps (1981–2024), as well as daily discharge records from the IMGW gauging station in Sierosławice. During the study, the water surface, exposed rock areas, and channel banks were vectorized. The measurement results were subsequently normalized to mean annual low flow conditions. Strong hydromorphological relationships were identified. Since 1997, a systematic narrowing of the water surface and an increase in rock exposure at comparable discharge levels have been observed, which is interpreted as evidence of progressive incision caused by channel regulation and aggregate extraction. The geosite assessment indicates that its scientific and educational value is high. In addition to natural processes, the long-term stability of this bedrock reach of the Vistula River will depend on river management and its purposes: flood protection, environmental conservation, or development of an inland waterway.