MONITORING AND MODELLING OF RIVER WIDENING PROCESSES IN AN ALPINE RIVER

摘要

Austria's river network is composed of running waters, with a total length of approximately 100.000 km, which have distinctively shaped the landscape. Over the past decades, both, river bed stability and ecological integrity of running waters have been endangered. Coupled with the new Water Framework Directive of the EC and National guidelines for river engineering as well as additional funding from the EC a variety of projects are realized. For improving the ecological functioning of water courses and minimizing river bed degradation an increasing number of river bed widenings has been implemented over the last ten years in Austria. Study of the impact of completed stream bed widenings shows both favourable overall effects and problems. Thereby stream bed widenings lead to a reduction of bedload transport capacity with reduction of river bed degradation and to an increasing form roughness as well as a positive ecological development. It is shown in the contribution that monitoring and modelling concepts have to incorporate these effects in order to be able to predict future developments concerning dynamic river bed stability and ecological integrity.