Crest modifications to reduce wave overtopping of non-breaking waves over a smooth dike slope: Fid-Bau Portal

Crest modifications to reduce wave overtopping of non-breaking waves over a smooth dike slope

Van Doorslaer, Koen / De Rouck, Julien / Audenaert, Sarah / Duquet, Valerie

Abstract The formula to quantify the average wave overtopping discharge of non-breaking waves over a dike according to the TAW-report (2002) and included in the EurOtop Manual (2007), only contains the influence of the roughness of the dike slope and the obliqueness of the waves on wave overtopping. Unlike the formula for breaking waves, the reductive effect of a storm wall or a berm is not included in this formula. Over 1000 scale model tests with non-breaking waves on a wide variety of structures have been carried out for this paper. The crest of the dike slope has been modified with a storm wall, a storm wall and parapet, a stilling wave basin, a promenade, and a combination of a promenade and storm wall with or without parapet. For all these modified crests, a reduction factor has been deducted to include in the wave overtopping formula of non-breaking waves. This paper presents the results of all investigated measures to reduce wave overtopping over a smooth dike slope in an easy and logical way to serve as a guidance for use by designers. An example is given where all presented measures are compared to each other, and to other well-known structures.

Highlights • This paper investigates reduction of wave overtopping of non-breaking waves. • A large data set was set up with over 1000 experimental tests. • Dikes with modified crest, with or without increasing the crest height, reduce overtopping. • Reduction factors for each measure are included in existing EurOtop-formula. • The paper is concluded by a case study, where different measures are compared to each other and other well known structures.