Background With a total area of over 10,000 hectares, the Donau-Auen national park in the floodplain to the east of Vienna contains one of the biggest and best-preserved regions of lowland riparian forest in Central Europe. However, the 30 km stretch of the River Danube which passes through the national park is also used intensively by river barges. The challenge is to demonstrate that the aims of nature conservation are not incompatible with the requirements of a modern navigable waterway. While the barges require a navigable channel which is as stable and safe as possible, the main requirements for the park administration are an adequate water supply for the lowland riparian forest and the extensive restoration of the branches and banks of the Danube to their natural state. Such considerations have led to the introduction of a “global approach to river engineering” adapted to the specific requirements of this part of the River Danube. Objectives Following an earlier LIFE-Nature project in the national park, which focused on reconnecting cut-off branches to the main river, this second project aimed to restore the river banks themselves to a natural state: all artificial elements strengthening the bank would be removed on a 2.8 km pilot stretch of the left bank of the Danube opposite the town of Hainburg, so that erosion and accretion processes again lead to the formation of natural river bank structures. The project foresaw the removal of 24,000 m³ of stone blocks. Within a few years the river as it flows through the restored area is expected to erode the steep bank to form a gently shelving shallow shore, with localised cliffs where the bank has collapsed. Shingle and mud banks, collapsed sections of bank and other elements of the floodplain landscape which have become rare would once again be formed directly on the main course of the River Danube. The project also planned actions for the national park floodplains near Orth. By deliberately steering national park visitors towards less sensitive areas of the floodplain away from the river, thereby reducing the disturbance of forest areas near the river, the foundations would be laid for recolonisation by sensitive species of large bird such as white-tailed eagles and cormorants. Results The project implemented extensive restoration measures on a scale hitherto not seen on a large European river. Such an achievement is remarkable given that the Danube east of Vienna is one of Europe’s most important shipping lanes. The removal of riprap on 3 km and forestry roads has vastly improved the river dynamics and ecological situation of the floodplains habitats and species within the project area. At least two new bird species – sand martin (Riparia riparia) and common tern (Sterna hirundo) – will soon breed in the area. Both species are typical bird species of natural riverbanks and gravel banks. Many other species of natural floodplains will also benefit from the project actions, including fishes, amphibians and insects. The closure of some of the forestry roads makes the access to remote areas of the project site much more difficult, and it is likely that the breeding success of large birds will increase. Moreover, this project has also contributed to flood protection of the cities of Hainburg (Austria) and Bratislava (Slovakia). Its approaches and results deserve a Europe-wide distribution and should draw the attention of other European river restoration projects. The project carried out a wide-ranging and highly effective public awareness-raising work. It hosted creative events like school arts contests and computer games in addition to the usual dissemination activities. Due to its ambitious approach the project was visited by river restoration experts from several countries (e.g. Germany, Japan, Switzerland, Hungary and Slovakia). It is noteworthy that the beneficiary will soon start with another ambitious river restoration project on the opposite riverbanks of the present project area. As this new project foresees the removal of bank reinforcements on several kilometres of riverbanks, its approach and objectives are comparable to the present LIFE-project. However, it is financed by the Viadonau – the partner of the present LIFE-project - and by the Austrian government. Further information on the project can be found in the project's layman report (see "Read more" section). This project has been selected as one of the 26 "Best" LIFE Nature projects in 2007-2008.