Dynamic roughness in rivers during floods


Andries Paarlberg

Marjolein Dohmen-Janssen

Suzanne Hulscher


University of Twente




Nov 2003 – Nov 2007


Accurate predictions of water levels during floods in rivers are essential for the design of an appropriate flood defence system. Water levels during floods are largely influenced by bed roughness in the main channel of the river, formed by large bed forms on the riverbed (e.g. dunes; see Figure). Dunes develop during floods as a result of the increasing discharge, leading to a dynamic roughness. Still, a lot is unknown about these bed forms and the resulting roughness, let alone about their development during floods.


This project aims at improving understanding of dynamic roughness in rivers during floods and developing a model concept to predict dynamic roughness during floods, which can be incorporated in existing hydraulic models. This will yield more accurate predictions of water levels during floods.