Large scale trends of bed level degradation
Innovative components
Sandy or gravel river beds are continuously evolving in response to flow conditions and to the sediment supply coming from upstream. These morphodynamic forcing mechanisms can be affected by river engineering measures such as channel widenings, placements or adjustments of navigation or flood-protection structures, dredging activities or rehabilitation measures such as re-meandering or side-channel connections. To be able to anticipate and appropriately act on morphological changes in rivers, it is important to link cause-and-effect relations between bed response and their dominating triggers. This is particularly important in highly-engineered navigable rivers, where multiple influences from close-by and further away can obscure the dominating causes of local bed level changes, and thereby possibly point in the wrong direction when it comes to sustainable river management practices.
Related outputs
Rivierbodemdynamiek meenemen in het ontwerp van maatregelen
In the Dutch Waal river, the bed topography of the navigational channel is measured bi-weekly. In a so-called TKI-project (cooperation between Rijkswaterstaat, HKV and Twente University) we use this data to link morphological changes to specific interventions in the river. This is not a straightforward as it may seem, because the morphological changes are the sum of small scale changes due to e.g. the presence of groynes, medium scale changes coming from the intervention and large scale changes coming from engineering measures in the (far) past to which the profile is still adjusting. A so-called wavelet analysis can be used to disentangle these different scales and enables us to focus only on the morphological changes due to the intervention. This improves river operations and maintenance and in the future also to facilitate the planning of new measures to minimize morphological impact.
01/10/2020 by Pepijn van Denderen et al.
Contains: Publication open access
Insight into the local bed-level dynamics to assist management of multi-funtional rivers
River discharge fluctuations cause bed-level variations at various scales, resulting from spatial gradients in the river’s geometry. Insight into these bed-level variations and their relation to discharge fluctuations can help to predict and prevent the formation of local bottlenecks. In this paper, we use bi-weekly bed-level measurements of the river Waal to estimate the bed-level variations related to the river discharge.
11/02/2021 by Pepijn van Denderen et al.
Contains: Publication open access
Last modified: 19/02/2021