Author(s): Helmut Schonlaub

Linked Author(s):

Keywords: Eco-hydraulics; Minimum acceptable flow; Vertical-slot-pass; Fish trap; Pool-pass; Steep slope river; Sediment transport; River bed morphology

Abstract: Having a design discharge of 4.6 m3/s and a head of 264 m, the 9.9 MW Schwarzach hydropower plant generates 59 Gwh/year. The 290 km2alpine catchment area ranges from 1100 to 3200 m asl. 1.5% of the area is covered by a glacier. The water for power generation is diverted by a so-called Tyrolean weir. Next to the weir a fish pass has been erected. It is linked with a complex system of outlet works for delivery of the minimum acceptable flow in the river. The fish pass is a vertical-slot-pass with a special adaptation for low rates of flow. The minimum acceptable flow is delivered through the fish pass, over a fixed weir and through a pipeline with a slide valve. The results of the first monitoring of the functioning were unsatisfactory. The reason might be a change of the morphology of the river bed, which is characterized as a steep slope alpine river with high sediment transport. To fix an optimum bait-flow current to the entrance of the fish pass, a pool-pass close to the natural river bed morphology has been constructed.

DOI:

Year: 2009