In the frame of DANUBEparksCONNECTED together with Nationalpark Donau-Auen and viadonau, an island revitalisation work at Wolfsthal island east of Vienna has recently been implemented.
Islands are ecologically important flagship habitats for river dynamics and home to characteristic species. Not only the island itself, but also side waters protected by the island are of high ecological value, for example they are important areas for fish spawning. The network of small side arms works like the capillary system of a floodplain. These small branches are important for the water regime as well as corridors for many semiaquatic animals and plants.
The regulation of the Danube in the past century caused several negative effects such as increased bed erosion, siltation of fine sediments in the floodplain or a lack of the longitudinal transport of gravel. The effects are problems in flood prevention and ecology.
The island of Wolfsthal is a stepping stone between the Donau-Auen National Park in Austria and the Danube Floodplains in Slovakia. It's covered by natural willow stands, and its vast gravel banks are home to rare insects and the sandpiper, which lays its eggs on gravel surfaces. This valuable island is untouched by forestry or any other form of management. However, it was rapidly losing its island character since its side branch was filled with sediments so the island has thus been connected to the mainland for most of the year.
This side branch has undergone a restoration by removing 9 groynes weighting nearly 6,000 tonnes. The construction work began at the end of November 2018 and due to the low water level suitable for the construction works, the revitalization could be carried out in record time and has already been completed. The Danube will thus be given the opportunity to flow through the area behind the island.
Hans-Peter Hasenbichler, Managing Director of viadonau, Gerhard Schödinger, Member of the Lower Austrian state parliament and Mayor of Wolfsthal and Carl Manzano, Director of the Donau-Auen National Park
This revitalisation is in line with the WILDisland initiative. "The creation of a wilderness island near Wolfsthal is another important step in ecological river engineering. " said Carl Manzano, director of the Donau-Auen National Park.
This revitalisation work should contribute to the improvement of water discharge and sediment transport by enabling water continuity and will play an important role in the preservation of the character of this island in the long term.