École Nationale Supérieure de
Techniques Avancées

Résumé

The Salzach River and its tributary the Saalach, both on the Austrian-German border, have been a water management problem for centuries. Measures taken in the mid 19th century to train the Salzach River lead to severe degradation problems. The riverbed erosion has reached a critical point, and a partnership between the Austrian and German Governments has developed a plan (Die Sanierung der Unteren Salzach) to restore the river and its tributaries to its natural state. One component of the project is the implementation of a ramp on the Salzach River at km 51.9. A common way to stabilize riverbeds is to construct a ramp, sill or weir. This structure raises flow depths in the upstream reach and thus promotes aggradation of the riverbed. It was decided that at km 51.9 a Rough Ramp be implemented into the river system. A Rough Ramp features many Steps separated by Basin structures. Due to the complex nature of this ramp a model test investigation is underway at the Oskar von Miller Institute (Technischen Universität München). The model investigation is a 2-Phase project, which is loosely based on another model investigation of the existing Salaach River Ramp. Phase 1 of the model test involves a 2-dimensional flume test in order to examine hydraulic conditions, acceptable stone sizes, Step and Basin configurations, energy dissipation, ramp stability, ecological aspects and constructability as well as boat passage over such a structure. Results from Phase 1 are to guide the construction of Phase 2, a 3-dimensional model test of the ramp, which includes riverbank interaction, downstream scour investigation as well as boat passage behavior. The results of the model test lead to a more effective and rational design of the final project.