Danube-Auen National Park on both land and water, and other invertebrates, the total number of species in Donau-Auen National Park is estimated to be at least 5,000. Danube-Auen National Park Donau-Auen National Park () covers 93 square kilometres in Vienna and Lower Austria and is one of the largest remaining floodplains of the Danube in Middle Europe. The German word Aue (variant Au) means "river island, wetland, floodplain, riparian woodland", i.e. a cultivated landscape in a riparian zone. The words Aue and Au occur in a large number of German place names—including Donau, the German word for the Danube River—and refer to forests,
Executive Agency for Exploration and Maintenance of the Danube River and inland waterway maintenance and implements projects in the frames of the Danube Strategy of the EU, Bulgarian-Romanian commissions, the Danube Commission, GIS Forum. Executive Agency for Exploration and Maintenance of the Danube River EAEMDR was established as an organization in 1935 under the name “Danube Hydrographical Service” within the structure of the Ministry of Railways. The headquarters were situated in the city of Lom and the responsibilities of the Service were related to the maintenance of the waterway, creation of maps of the Danube River, conduction of hydro meteorological surveys in the Bulgarian section of the river. In 1949,