The restoration of the Aufhausener Lacke

An initiative by LIFE Riverscape Lower Inn promoting greater aquatic biodiversity on the Lower Inn

The LIFE Riverscape Lower Inn project comprises a wide range of measures aimed at improving the condition of standing waters within the European protected area. One of these was the restoration of the Aufhausener Lacke.

The Aufhausener Lacke was a body of standing water on the left bank of the Inn between river kilometres 44 and 42. Over time, it became increasingly silted up. Floodwaters deposited sediment, filling in the body of water and its connection to the Inn. This process took place over several decades. Since 2022, it has been dry all year round. As the dynamics in the floodplain on the river side of the embankments are insufficient to flush out the sediment again, structural measures are required here. All previous measures had only provided short-term relief – a more ambitious solution was needed.

VERBUND revitalised the Aufhausener Lacke in the winters of 2024 and 2025 as part of a major project. Large quantities of sand were dredged out. The refilling at the end of March 2025 led to rapid success: the new Aufhausener Lacke has developed into a structurally diverse body of standing water that will provide valuable habitat for decades to come.

The new Aufhausener Lacke has been designed to be as close to nature as possible – with gently sloping banks, a variety of shallow and deep areas, and a direct connection to the River Inn. This diverse body of standing water has provided a habitat for numerous animal groups, including waterbird species, amphibians, crustaceans, mussels and insects, for decades. Clear-water areas up to 2 m deep are vital for species such as the coot – yet such areas have become rare along the River Inn.

The Aufhausener Lacke lakes provide this rare habitat and were quickly repopulated by coots. The newly created shallow-water areas attract the green sandpiper, a waterbird that can now be seen here all year round. It often uses old blackbird and song thrush nests for its young.

Thanks to the connection to the River Inn, fish can once again reach the Aufhausener Lacke. The newly created shallow-water areas, with their emerging aquatic vegetation, provide a perfect environment for fish larvae and fry, as well as for bottom-feeding waterbirds.

Restoration measures such as those at the Aufhausener Lacke are a key component of the LIFE project to enhance the floodplain landscape along the Lower Inn, and they boost biodiversity right on our doorstep.

Successful restoration of the Aufhausener Lacke – a sound approach

Within just a few months during the winter of 2024/2025, VERBUND removed over 70,000 m³ of sediment and relocated it to the banks of the Inn. When water levels rise, this sediment is carried further downstream without significantly increasing the Inn’s natural suspended sediment load. As the Lacke is connected to the Inn downstream, sediment input remains low and an attractive area of clear water is preserved over the long term. The involvement of local fishermen and fisherwomen over more than 25 years, the commitment of project partners and the implementation supported by experts have made this ecologically significant restoration possible.

The LIFE project ‘Riverscape Lower Inn’ comprises a wide range of measures aimed at improving the condition of standing water bodies. In addition to the Aufhausener Lacke, there are numerous other areas along the River Inn which have undergone a similar negative ecological development as a result of progressive silting and are due to be renaturalised.

As the floodplain waters provide vital habitats for a wide range of rare animal and plant species, the renaturation – and thus the enhancement – of the habitat quality within the Inn river landscape is a key objective of the LIFE project.

The measure improves habitat diversity in the Lower Inn European Nature Reserve and, in particular by boosting fish populations, also makes a significant contribution to the implementation of the EU Water Framework Directive.