Designing the construction concept of the protective forest of EGGA.

The torrent catchment Schliefwaldtobel in the northwest Raetikon is characterized by extremely heterogeneous geological conditions. The distribution and composition of the forest vegetation and the influences of management (forest-grazing, winter sports) affect the discharge and erosion. Management as well as the protective function of the forest were examined regarding hydrologic and geomorphologic processes. For the optimization of the protection and welfare functions of the forest suitable measures were suggested against the slide and erosion endangerment as well as for the improvement of water retention in the area. In a geographical information system the probability of gravitativ processes was measured such as slide and falling rock processes with dynamic logical operations (fuzzy logic). The connection of discharge-determining soil moisture conditions was examined with indicator plants. The results of the calculations of the precipitation drainage model Geohec-1 served as basis for flood control of the catchment areas of the Staudenbaeche which were strongly modified by men made changes.