Author(s): Michael Hengl; Herwig Korger; Norbert Krouzecky
Keywords: Degradation; Bed stabilisation; Ramp; Ecology
Abstract: In the river Saalach the first step pool ramp for flowing waters of HQ100 (i. e. 1 000 m³/s) was built. The construction for morphological river bed stabilisation for rivers with bed load transport can be applied up to a design discharge of several thousand m³/s. This paper describes the construction mentioned above, which was developed in the course of a series of hydraulic model tests, and which fulfils the requirements of sustainable stabilisation of the river bed, stability of the construction during high water periods and passibility for all fish species native to the river. Additionally it was possible to integrate aspects of design and leisure time usage (canoeing). In order to ensure the stability of the construction during high water periods, the max. stone size of the steps of the step-pool system has to be between 5. 5 to 7 to. Although the construction is quite an irregular one, no problems arose during construction work. Based on its ecological advantages (passibility for fish) the design introduced in this paper is to be taken into account as a suitable measure for morphological stabilisation of river beds in the future.