New Study for River Waal

Deltares is teaming up with Rijkswaterstaat, the universities of Delft, Wageningen and Nijmegen, and organizations representing shipping and fishing to investigate the impact and properties of the re-structuring of the River Waal with river training walls.

Gerard Blom signed an agreement on behalf of Deltares with the other seven organizations on 26 June.

This joint study has been established to determine whether it is useful to replace groynes with river training walls at several locations in Dutch rivers.

River training walls make floods less likely

During the past year, Rijkswaterstaat has installed river training walls in the River Waal between Wamel and Ophemert.

The walls are new to Dutch rivers. They are embankments parallel to the flow of the river. The construction of the river training walls has resulted in a drastic re-structuring of the summer bed.

Instead of a single main channel with groynes, there are now two parallel channels: a wide main channel for shipping and a large bankside channel. Because river training walls with bankside channels are parallel to the flow of the river, it is easier for the water to pass by when the river level is high than with groynes.

That makes floods less likely.


Re-structuring expected to have positive impact

It is expected that the re-structuring using training walls will have numerous positive effects, for example because of the unique way in which the river water is divided between the two channels.

There are openings in the training walls that can be made larger or smaller.

Rijkswaterstaat expects the training walls to have a beneficial impact on low water levels, sailing depths for shipping, the development of flora and fauna, the water regime (preventing drying-out), river management and maintenance (stopping the subsidence of the river bed and reducing the need for dredging).

Five themes

The intensive research program covers five themes: technology, nature development, public and professional perceptions, management and maintenance, and costs and benefits (direct and indirect).

The results of the study can be used as a basis for re-structuring operations using river training walls in the future in other locations. Deltares will produce the integrated report about all the areas monitored as part of this study.

In addition, in the context of the STW Rivercare project, experts Erik Mosselman and Tom Buijse will be involved in the supervision of two doctorate studies. At Wageningen University, the focus will be on hydraulics and morphodynamics, and Radboud University will concentrate on ecology.

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