Kortenhaus, A.

Streicher, M.

Troch, P.

Open Marine Archive

 25 
Wave impacts on storm walls: Large scale experiments in the Delta 
flume 
Streicher Maximilian, Kortenhaus Andreas and Troch Peter 
Department of Civil Engineering, Ghent University, Technologiepark 904, 9052 Gent, Belgium 
E-mail: maximilian.streicher@ugent.be  
 
1. Introduction 
 
Coasts of low lying countries, such as The Netherlands, Belgium, UK and Germany are often comprised 
of a gentle foreshore and shallow waters, followed by a dike and a promenade. At the end of the 
promenade buildings or storm walls are constructed. In this setting waves can overtop the dike and 
impact on the storm wall or building. Commonly design guidance for overtopping and overtopped 
bore impacts for this set-up are developed in relatively deep water conditions, neglecting the 
dissipation of wave energy due to depth-limited wave breaking on the foreshore. Recently, the 
reduction in overtopping, the increase in wave periods at the toe have been experimentally studied 
for shallow water and gentle foreshore conditions. Furthermore, numerical simulation have been 
performed in the past. Small scale experiments of overtopped wave impacts on walls are conducted 
and design guidance for overtopped wave impacts on walls for shallow water and gentle foreshore 
conditions were derived. However, a validation based on large scale experimental data of overtopped 
wave impacts for this set-up is still missing. 
 
2. WaLoWa objectives  
 
Within the European project ‘Wave Loads on Walls’ (WaLoWa) model tests in the Delta flume (The 
Netherlands) have been conducted in March 2017. The project is a cooperation of Ghent University 
(Belgium), TU Delft (The Netherlands), RWTH Aachen (Germany), University of Bari, University of 
Florence (Italy) and Flanders Hydraulics Research (Belgium). The project is financed by a grant 
by Hydralab+ in the framework of the EC Horizon 2020 program. The program provides researchers 
access to large scale coastal engineering test facilities in Europe. The main objectives are: (a) to study 
the impact behavior of overtopped waves on vertical structures (b) to study scale effects by comparing 
the obtained results to small-scale experiments conducted using a similar geometry, (c) to analyze 
bed profile changes and suspended sediment concentration of the sandy foreshore, (d) to validate 
numerical models in terms of wave evolution over the foreshore and wave impacts on the wall, (e) to 
study the overtopped flow formation on the promenade and (f) to apply new measurement techniques 
for this set-up. 
 
3. Experimental set-up  
 
The scale model geometry is divided into four parts: (1) A sandy foreshore with a slope of 1/35 over 
a flume length of 80m, made from ~1000m³ of sand, (2) Both a concrete dike with a 1/2 slope and 
(3) a 2.3m wide promenade are attached to the foreshore, (4) A vertical, 1.6m high wall at the end of 
the promenade. All values are given in model scale using Froude similarity 1/4.3 and are given more 
detailed in Streicher et al. (2017). Irregular and Bichromatic waves were tested during the 
experiments. Waves representing a storm with a 1000 year return period and an additional water level 
to account for sea level rise result in the tested superstorm conditions. In (part 1) the incoming wave 
parameters and morphological evolution of the sand bed are measured, in (part 2) the run-up and 
overtopping are surveyed. In (part 3) the overtopping flow parameters layer thickness and velocity 
are monitored and in (part 4) the impact forces and pressures on the wall and the flow aeration are 
measured. 
 
4. Discussion  
 
During the VLIZ talk the large-scale WALOWA model tests, conducted in the largest wave flume facility 
of the world, will be presented. An outline of the objectives, model construction, test program and 
measured parameters will be given. With the obtained large-scale data set a detailed study of wave 
impact processes along the coasts of shallow waters and gentle foreshores is enabled and numerical 
model validation facilitated. The importance of large-scale physical model testing in coastal 
engineering will be addressed by highlighting preliminary results. More detailed the pressure 
distribution induced by a wave impacting the wall will be discussed. 
 
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Acknowledgement  
  
The work described in this publication was supported by the European Community’s Horizon 2020 
Research and Innovation Programme through the grant to HYDRALAB-PLUS, Contract no. 654110. 
 
Reference 
 
Streicher, M., Kortenhaus, A., Altomare, C., Gruwez, V., Hofland, B., Chen, X., Marinov, K., Scheres, 
B., Schüttrumpf H., Hirt, M., Cappietti, L., Esposito, A., Saponieri, A., Valentini, N., Tripepi, G., 
Pasquali, D., Di Risio, M., Aristodemo, F., Damiani, L., Willems., M., Vanneste D., Suzuki, T., Klein 
Breteler, M., Kaste, D. (2017). “WALOWA (Wave Loads on Walls) – Large-scale experiments in the Delte 
Flume”.  Proceedings of the 8th SCACR conference 3rd – 6th October, Santander (Spain). 
 
Keywords: coastal engineering; storm walls; overtopping; wave impacts; large-scale experiments  


Wave impacts on storm walls: Large scale experiments in the Delta flume

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Wave impacts on storm walls: Large scale experiments in the Delta flume

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