The Salzach flows north unhindered for more than 50 kilometers before it flows into the Inn shortly after Burghausen. It is considered to be the last river in the foothills of the Alps in Bavaria that can flow freely over long distances. But there are narrow limits to freedom: Because the Salzach has been separating Bavaria from Austria since the 19th century and both states did not want a meandering border with gravel banks in no man’s land, the river bed was straightened, set to a width of 60 Viennese fathoms or 114 meters and appropriately fastened. The river is digging deeper and deeper into this channel, which is why on both sides of the border it has long been a matter of preventing its bed from breaking through and widening the banks again.
The Bavarian state government would be only too happy to build new hydroelectric power plants on this occasion, which would then also end the free flow in the long run. But now an official report has come to the conclusion that the Salzach can be rehabilitated without major intervention. Nobody wants to put the study on the table for the time being.
Currently, it is primarily Prime Minister Markus Söder (CSU) who is talking about expanding hydropower on the Salzach in view of the Ukraine war – most recently after the cabinet meeting in mid-May, when Bavaria’s “home energy” was discussed. The Ministry of the Environment had identified 30 potential locations at existing transverse structures across the country, it said at the time. The aim is to develop a potential of around 160 gigawatt hours of electricity production annually. For comparison: the ongoing renewal of the Inn power plant near Töging alone brings an additional 140 gigawatt hours, its then 700 gigawatt hours per year should be enough for 200,000 households.
But on the Salzach there are only transverse structures on the upper reaches, where the Austrians have long since built numerous power plants. These are the main reason why the natural debris of crushed stone and gravel is missing in the lower reaches. This is one of the reasons why the river cuts deeper and deeper there. According to a study from 2014, this could be countered with further transverse structures, among other things – and the state government has long wanted to use such transverse structures for hydropower.
In the Tittmoninger basin, the bed of the Salzach resembles a narrow canal that is exactly 114 meters wide. Nevertheless, it is considered to be the last free-flowing river in the foothills of the Alps in Bavaria.
(Photo: State of Upper Austria/GWB Braunau)
The Austrian group, which also operates the German-Austrian border power plants on the Inn, proposed up to three power plants with a total production of 100 gigawatt hours per year. In 2019, however, both countries agreed that “from a river engineering point of view, only one transverse structure below the Laufen Enge is currently required,” as a spokesman for the Bavarian Ministry of the Environment announced, emphasizing: “There will be no new transverse structures just for hydropower reasons.”
However, according to SZ information, a new bed load study commissioned by both countries has now shown that, from the point of view of river engineering, a transverse structure is no longer necessary. Accordingly, the Salzach brings more debris than expected. According to the study, this debris would be enough to stabilize the river bed if the Salzach itself could fetch additional material from its banks. For this purpose, the responsible water management office in Traunstein had the paved river banks south of Laufen broken up a few years ago and has been allowing the authorities in Upper Austria to do the same north of Tittmoning for a few months. Then the river could also create a near-natural floodplain forest in places.
This result fits in with the ideas of the “Action Group for Habitat Salzach” from several nature conservation organizations that have opposed all power plant plans for decades. It is all the less in line with the state government’s “home energy” strategy and Söder’s recent announcement. The Ministry of Economic Affairs led by FW boss Hubert Aiwanger refers to the Ministry of the Environment of Aiwanger’s party friend Thorsten Faithr on the subject. There it says that before further decisions are made, “the currently ongoing energy policy discussions at EU and federal level must be awaited”, the final assessment will be made “by the responsible Bavarian Ministry of Economic Affairs”.
The Federation of Nature Conservation is part of the “Action Group Habitat Salzach” and its final evaluation is already very close. Söder’s plans are “incomprehensible from our point of view,” says BN chairman Richard Mergner, because they contradict all nature conservation provisions under European law. The fact that the Ministry of the Environment is not making the finished bedload analysis public “we consider to be political manoeuvring.” Because the study also comes to the conclusion, based on the information from the BN, that no transverse construction is necessary.