Development of scour in non-cohesive sediments under a poorly erodible top layer

Development of scour in non-cohesive sediments under a poorly erodible top layer

Van Zuylen, J.A.
Sloff, C.J.

Civil Engineering and Geosciences

Hydraulic Engineering

2015-08-30

This study deals with the development of deep scour holes in the river bed of the Dutch Rhine delta in the Netherlands. Assessment of multi-beam surveys, laboratory-flume experiments, and 3D numerical modelling, shows how fast this type of scour holes grows in depth and width. These typical scour holes are found in the tidal deltaic rivers that experience a general incision. This erosion decreases the thickness of the erosion resistant clay/peat layer that is covering and protecting the underlying Holocene and Pleistocene sand (Sloff et al, 2012). Consequently, when this layer breaks, deep scour holes are formed where easily erodible sand is exposed. These scour holes pose risks to the stability of nearby embankments and structures. Laboratory experiments were designed on basis of the field observations, showing rapid deepening, and only slow growth in horizontal dimension. Subsequently, the findings of the flume experiments were used to study and understand the flow in the scour holes in more detail, using a numerical model, and introducing different flow conditions and calculating the shear stresses.

http://resolver.tudelft.nl/uuid:48d2b7cc-be92-4276-958b-fd85ecb1ad3e

RCEM 2015: 9th Symposium on River, Coastal and Estuarine Morphodynamics, Iquitos, Peru, 30 August-3 September 2015

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conference paper

(c) 2015 The Author(s)