18. Gesäuse: River Gorge, Limestone Massifs and Sediment Cascades

Gesäuse is the name of a huge gorge the Enns River has cut into the Northern Calcareous Alps forming an impressive scenery with a relative relief of up to 1800 m. Besides a topographical overview, this chapter presents the most important facts on the interplay between lithology and relief and the impact of the Pleistocene glaciation on the region. Remnants of palaeosurfaces are discussed with respect to morphogenesis, resulting in a hypothesis on the development of the Gesäuse Gorge. Furthermore, we provide insight into ongoing research focussing on sediment cascades. The results show that in the picturesque dolomite landscape around the Johnsbach tributary river, rockwall retreat rates are exceptionally high. The debris is transported to the Johnsbach by episodic debris flows. There is a considerable human impact by former gravel mining and by undersized bridge openings, disconnecting some side valleys from the main river. Further interactions of geomorphology and socio-economic activities are discussed with a focus on natural hazards and nature protection (Gesäuse National Park). Finally, some selected future research agendas are outlined.