River fish are massively affected by the loss of habitat diversity and dynamics as well as the wave impact of constantly increasing shipping traffic. Therefore, the reactivation of side arms protected from the impact of waves, still water bays and flat overflown gravel banks are of special importance in the revitalisation of the Danube. The near-natural Pielach river is the most important tributary of the Danube in the Wachau. Unhindered spawning migrations of Danube fish such as the common nase, barbel and Danube salmon into the Pielach are of major ecological significance.
The LIFE+ project Mostviertel-Wachau includes measures on the Danube and the Ybbs river. Revitalisation measures are being implemented on the Ybbs in Amstetten and on the Pielach, and disconnected side arms of the Danube are being reconnected to the river in the Wachau.
Project promoter: Province of Lower Austria (Dept. of Hydraulic Engineering) with the participation of viadonau, the municipality of Amstetten, Stadtwerke Amstetten public utility board, Lower Austrian Provincial Fishing Association, research community LANIUS and of the Ministry of Sustainability and Tourism (BMLFUW); the project management of the projects in the Wachau was carried out by the Arbeitskreis Wachau Regionalentwicklung (today Welterbegemeinden Wachau association) in cooperation with land.schafft technical agency.
Project duration: 2009 - 2014
Project costs: approx. €6,685,000 (50% EU), of which approx. half in the Wachau
Subsequent measures of the LIFE+ project created decisive ecological improvements to the running water habitats on the Danube and Pielach.
Schallemmersdorf side arm: The remains of a historic side arm on the left bank of the Danube were dredged along the entire length of about 2 km and a spacious inflow area was created. Downstream, the side arm flows into another, previously revitalised side arm. Shallow fords, deep potholes, steep and flat bank areas form a mosaic of diverse habitats.
Schönbühel side arm: On the right bank of the Danube, a 1.5 km-long side arm was restored and wave-protected habitats created for endangered species of Danube fish. The island of riparian forest created and the surrounding gravel banks offer a calm natural zone for species such as the common sandpiper and little ringed plover.
Frauengärten biotope: The extensively silted up area of bank between Weißenkirchen and Dürnstein was dredged as part of a project, the blockstone embankment removed and an old course created with a connection to the main stream at one end. In this way, a calm waterbody and so-called “mudflats” on the mudbanks and sandbanks were created.
Pielach mouth: The construction of the Danube power plant at Melk made it much more difficult for spawning Danube fish to migrate into the Pielach through a stone ramp. In the course of the LIFE+ project, plots of riparian forest were purchased and a new structure-rich mouth stretch of the Pielach with a flatter gradient was constructed. The spawning migration of fish such as Danube salmon, common nase and barbel is now possible again.
Lateiner old course: This former old course was connected to a near-natural stream during work on the mouth of the Pielach and can now be reached by herbaceous spawning fish. Investigations revealed that 28 species of native fish migrated through the interconnecting stream.
Pielach mouth-Steinwand conservation area: In the lowermost reaches of the Pielach, the LIFE+ project purchased 20 hectares of riverbank land and hillside forests in order to create the Neubacher Au, a wetland conservation area. These near-natural stands of deciduous forest and rocky areas with dry grasslands are of particular importance from a botanical perspective. Over 40 endangered plant species have already been identified.