Drain Fascines to Foster Dewatering Processes in the Fürwag-Landslide

The Fürwag-Landslide is situated north of Salzburg (A), where Flysch formations covered by moraine materials dominate the geological bed rock. In this area landslide processes, which have been reported since the 19th century, were reactivated in the 1980s. Since then signs of latent gliding activities on various sites have been observed repeatedly. In 1998 new activities seriously endangered nearby infrastructures such as gas pipeline, local railway tracks and a first grade road. To minimize the risk of massive movements an extensive drainage pipe system was installed. In addition to the technical stabilization of open gullies the sliding area was afforested with Black Alder. A couple of years later rock fall not only reactivated the landslide locally but also destroyed the drainage system. Additionally to the restoration of the dewater network a complex geological, hydro geological and morphological examination program was started to gain an insight into the factors causing the constant activities. For further drainage purposes drain fascines consisting of dead and live plant material will be constructed in the middle parts of the landslide. The development of the vegetation, the root system and its influence on the soil water regime will be investigated.