Experimental study on wave-overtopping erosion for flood defence reliability

Type
PhD research

Duration
2017-2021

Persons involved
Weiqiu Chen, MSc. (PhD candidate)
Prof. dr. Suzanne J.M.H. Hulscher (Promoter)
Dr. Jord J. Warmink (daily supervisor)
Dr. Marcel R.A. van Gent (Deltares, external supervisor)

Funding of the project
NWO – STW

Summary of the research
This PhD project focusses on the wave overtopping and wave-overtopping erosion of flood defences. During storms, waves overtop the dikes and cause water hindrance behind the dike and erosion on the seaward and landward side of the dike. Failure of a dike cover due to wave overtopping erosion may initiate dike breach. Surface transitions in the grass cover, such as cure points, height difference and roughness and permeability difference of the revetment are often weak spots. The effects of transitions on wave overtopping flow and, therefore, on the location and evolution of dike cover erosion are highly uncertain.

The goal of the project is to gain better understanding of the wave overtopping flow related to transitions on the dike crest and slopes. In this project, flume and field experiments are carried out to study the effect of changes in roughness and permeability on the waterside slope revetments on wave overtopping discharge. Detailed measurements of the overtopping flow serve as calibration and validation data for the development of numerical models. Furthermore, this project provides knowledge to develop technical measures for innovative dike revetments, such as grass-blocks or geotextiles and to improve maintenance strategies, such as moving, mixing vegetation types and grazing strategies.

This project is part of the All-Risk program: “Implementation of new risk standards in the Dutch flood protection program”. This program investigates flood risk and how measures such as flood defences can reduce this risk. The All-Risk program is a collaboration of of various universities (UT, TUD, RU, UU and WU), research institutes (NIOZ and Unesco-IHE) and a wide variety of users.

Keywords 
Wave overtopping, dike erosion, transitions, flood defence reliability, flume experiments.

Other stakeholders
Stichting Toegepast Onderzoek Waterbeheer

Rijkswaterstaat

Deltares

HKV – Lijn in water

Royal HaskoningDHV,

Arcadis

Witteveen en Bos

Hillblocks

Waterboards Rivierenland, Aa en Maas, Vechtstromen, Noorderkwartier

More information
Weiqiu Chen
Room Horst W203
Tel. +31 53 489 7880 
E-mail w.chen-6@utwente.nl