The Stockerauer Au is a nature reserve in northern Lower Austria. It extends south of Stockerau to the Danube. The floodplain was declared a nature reserve in 1999. With a size of about 346 hectares next to the size it is also protected for drinking water supply for the city as a debit and a recreation area. There is an extensive trail system.
The original floodplain is over time due to the slow erosion of the Danube in Vienna dry. Today, the floodplain of the casting path is irrigated artificially created, which was built in the course of building the power plant Greifenstein. The casting path begins four kilometers below Altenwörth and flows through the floodplain to 42 kilometers in length. Six kilometers downstream from the power plant Greifenstein it flows back into the Danube. Completed the casting path in 1984. The water flows from the casting path, however, not directly from the Danube but is filtered down through the gravel into the artificial lake. Only at high tide the casting path is directly powered by Ström specially created with the Danube water. Thus even in the Au constantly changing water levels are reached, resulting in a lush vegetation and provide a habitat for numerous species. The water quality of Gießganges has now continuously on the quality class 2.
In the waters of the Au Stockerauer now live 41 species of fish, of which only 15 are an endangered species in Austria. So you find bitterling, spined loach, sable, the gruff-like nerds, and Schrätzer Zingel and predators burbot, arbitration, pike and catfish. Due to the abundance of fish, but many species of birds have been attracted. Of the 70 endangered species alone, especially kingfishers, hen harrier, cormorant, gray heron and Silver, Red and Black kite, white stork, to mention sea and fish eagle.