Kraftwerk Hochwurhr

previous state

The River Ill is a tributary of the Rhine, which has a concentration of hydraulic dams as it flows through the Austrian state of Vorarlberg. As it passes through the small medieval city of Feldkirch, it forms a steep gorge between two cliffs over one hundred metres high. The river shares that narrow gap with the viaduct of State Highway B190 and the more than century-old Hochwurhr hydroelectric power station. Despite the beauty of the spot, until recently that concentration cut it off completely from the adjacent old quarter of the city. Moreover, the poor state of the power station installations meant that it yielded little energy and was in urgent need of renovation.

aim of the intervention

Despite the technical specificity of the renovation, Feldkirch Town Council saw an opportunity to recover the gorge of the river as a public space for the city. And so, with an investment of 12 million euros a new hydroelectric dam was built between 2001 and 2005. In addition to meeting its particular infrastructure functions, it includes a bridge and a garden that round off the old riverside avenue from the city centre.

description

The new construction concentrates most of its built volume on the north bank of the river and reaches the other side with minimum expression, while keeping a respectful distance from the cliff. In that way, while softening its environmental impact on the natural landscape, it becomes more present on the built up shore, where the old power station and the viaduct are located. Here it broadens out to form a gardened courtyard which provides access to the turbine room, equipped with picture windows that make it visible from outside. The garden is crossed by a 'fish ladder', a gently sloping channel that connects the two sides of the dam, with a total fall of ten metres. The channel is equipped with a series of obstacles to slow down the passage of the water and allow the fish to migrate upriver. At night the garden is still accessible thanks to Peter Sandbichler’s lighting project. The garden leads to the footbridge that follows the upper part of the wall of the dam and crosses the river with a central view of the whole gorge. That new walkway brings continuity to Count Rudolf Wuhr avenue, which begins in the centre of Feldkirch and until now ended before crossing the river.

assessment

The new dam intelligently combines infrastructure and public space functions. The two functions give it a dimension which is both territorial and local. The territorial dimension is provided by its energy output; its fifty thousand litre a second flow generates enough energy to supply four thousand towns the size of Feldkirch. This disproportion would mean that we were looking at one of the frequent cases in which a middle sized town is unfairly penalised by the impact of a major infrastructure on a territorial scale. The injustice is compensated by the local dimension of the garden and the footbridge, public spaces which both improve the connection between the city and the River Ill and its spectacular gorge and, instead of hiding the hydroelectric power station, make it available to the townspeople with a frank, educational attitude.

David Bravo Bordas, architect