"Fish promenade!" in Oberaudorf-Ebbs

The Grenzkraftwerke GmbH, a 100% VERBUND subsidiary company and operator of the hydropower plants on the Bavarian-Austrian border between the Inn and the Danube rivers, opened a new fish bypass at the Oberaudorf-Ebbs power plant as well as a new fish nature trail today, together with the mayors of the power plant municipalities, Ökonomierat Josef Ritzer from Ebbs, Christian Ritzer from Niederndorf, and Hubert Wildgruber of Oberaudorf. In honour of the opening ceremony, 120 school children from the three power plant municipalities in Tyrol and Bavaria decorated the guiding wall of the vertical slot fish pass, which was just as proudly presented, on the theme of fish and water. The construction of the fish bypass and the fish migration path lasted about nine months. The fish bypass is 850 metres long and offers indigenous fish such as the Danube salmon, the grayling, the barbel and the common nase, as well as other aquatic creatures, the possibility of independently bypassing the power plant. More than that, the site also represents an asset for the popular local recreation area.

New living space for flora and fauna

On the basis of the European Water Framework Directive, all high-priority running waters in the European Union, such as the Inn, are to be made traversable for aquatic life, to which end so-called fish bypasses can be implemented.

In 2013, VERBUND began the construction of just such a new fish bypass at the Oberaudorf-Ebbs power plant. It is divided into three sections and is located on the Austrian side of the Inn River. The underwater connection is made over a natural pond, stretches over the remodelled drain channel as a natural body of water, and leads through a vertical slot pass to the exit into the estuary region of the Jennbach and the Inn. In this way, voyaging fish and aquatic creatures find their way from the lower reaches to the section of water above the power plant.

VERBUND project leader René Tezzele: "The new fish bypass spans a total height of around 12.5 metres from downstream of the power plant to the headwater with the help of three different types of construction. Entrance downstream takes place over a natural pond pass, and the bypass subsequently proceeds over a natural channel. The last hurdle is overcome in the form of a vertical slot pass. In the topmost exit structure, a self-operating valve ensures a constant volume of outward flow." A minimum of 1,000 litres per second flows through the entire migration channel, reaching up to 3,000 litres per second in the high-flow summer months. A self-operating pump system takes care of the maintenance measures in the vertical slot pass, to ensure a constant flow of 60 litres per second so that the system does not dry out.

The new fish bypass not only provides for the traversability of the river, but also creates new habitats. Aquatic creatures thereby gain additional space for the search for food, reproduction, and retreat during a flood. In this way, these measures contribute significantly to the preservation and improvement of the fish population of the Inn.

"The conception of the fish bypass at the Oberaudorf-Ebbs power plant, as with all the other measures, was coordinated in advance with the responsible authorities and routinely guided by the authorities' experts in the field. Thanks to the positive collaboration among all those involved in the project - authorities, municipalities, technical planers and construction firms - the construction measures were able to be successfully completed," Tezzele reports.

120 school children excited in the process

In honour of the opening of the fish bypass, VERBUND gave some thought to the design of the structures and, before the event, invited the primary- and grade-schools of the project municipalities in Ebbs, Niederndorf, and Oberaudorf to decorate the guide wall of the fish bypass at the vertical slot pass.  In a border-crossing project, 120 fourth-grade students from Tyrol and Bavaria painted the 120-metre-long cement wall around the theme of fish and water. They were very excited about the topic and learned everything about electricity from hydropower. Photos and information on the Ebbs, Niederndorf, and Oberaudorf schools' creative design of the wall are also available here in the VERBUND blog: www.verbund.com/bg/de/blog/2015/07/03/malaktion

The role of hydropower in a sustainable energy system

Electricity from hydropower has many different functions in the energy system. Grenzkraftwerke power plant group leader Karl Maresch: "The run-of-river power plants on the Bavarian Inn and on the border between Bavaria and Austria are in operation 24 hours a day and so provide the necessary base load for the region. Water power is CO2-neutral and resource-efficient, reducing dependence on the import of fossil fuels and so making a pivotal contribution toward climate protection.“

VERBUND is particularly focussed on the securing of flood protection as well as on ecological concerns in the river - the numerous structural improvement measures and fish ladders that have been carried out or are still being planned illustrate this. "We feel very connected to the region, and it should stay that way," says Maresch.

The Oberaudorf-Ebbs water power plant

The Oberaudorf-Ebbs hydropower plant was built between 1988 and 1992 and generates over 268 million kilowatt-hours of electricity per year. This corresponds to the electricity consumption of around 77,000 private households. Beyond that, in comparison with a coal-fired power plant, more than 217,000 tons of CO2 can be spared every year.

The Oberaudorf-Ebbs run-of-the-river power plant: www.verbund.com/oberaudorf-ebbs and www.verbund.com/inn