Author(s): Corrado Gisonni; Willi H. Hager
Keywords: Bank protection; Failure; River training; Scour; Spur
Abstract: Spurs are widely used as an appropriate river training technique to prevent bank erosion; in addition spur dikes may preserve sustainable ecological conditions along rivers. Following a detailed literature analysis, a systematic experimental campaign was set up to characterize the hydraulic performance of spurs placed along a straight river branch and to study the scour phenomena originating from their construction. First, the effects of various parameters on scour advance were investigated, namely the spur length, the spur spacing, the spur height, along with the main hydraulic and sediment parameters. Further, a basic riprap revetment was considered as an effective technique to counter local scour at spur heads; experimentation showed that a riprap protection may fail due to various scour mechanisms. A data analysis led to design equations available for river engineers, to guide the riprap design and the prediction of its failure mode. The limitations of the recommended criteria are finally highlighted.