The Traisen is one of the largest rivers in Lower Austria. During the construction of the Danube power plant of Altenwörth, the length of the Traisen was extended by 7.5 km and, today, flows into the Danube downstream from the power plant. The river bed used to run straight and uniformly through the wetlands area between Traismauer and Zwentendorf.
The river section offered little habitat for typical wetland flora and fauna and was not connected to the surrounding countryside and water bodies in the wetlands. Fish accessibility and traversability were obstructed and in places completely impossible.
Over the course of ten years, consideration was given to how the Traisen section and the wetlands could be improved from an ecological viewpoint. Starting in 2005, scientists and technicians studied the idea of creating a new River Traisen. The intention was that it be closely linked with the wetlands and offer diverse habitats, as well as restore fish accessibility.
During the course of a strict selection procedure involving 270 European environmental projects, the "Traisen project" was approved at the end of 2008 for an EU grant from "LIFE+". The construction work was completed in 2016.