Author(s): Helmut M. Habersack; H. P. Nachtnebel
Linked Author(s): Helmut Habersack
Keywords: No Keywords
Abstract: The objective of this paper is to assess the efficiency of local river restoration measures to cope with river bed degradation. A project was initiated for the river Drau in Austria for a section of about 60 km length exhibiting major degradations of the river bed. The reasons are the reduced sediment delivery from upstream and from the tributaries and the river training works implemented in the twenties and thirties. The whole restoration program is planned to be stepwise realized and in a first approach a river section of about 300 m has been modified in its cross section width to reduce shear stress. The redesign of the cross section was based on numerical modelling of sediment transport. The efficiency of this measure was analysed by subsequent monitoring over a period of three years where several floods exhibiting a return period of a few years had been observed. At least in the short term the taken action corresponds to the planning objectives. Nevertheless it could be demonstrated that the effect of this measure on the sediment transport was only to the short section and therefore merely a chain of local restoration measures allows to improve the technical and ecological situation of the whole reach.
Year: 1997