This project is funded by TKI Deltatechnologie UTW01
The side channel at Nijmegen-Lent in the river Waal
Project output
Insights into the morphological changes in rivers with and without river interventions.
Challenge
The management of rivers requires the consideration of river functions such as flood conveyance, ecology, and navigation. River interventions, such as side channels and longitudinal dams, are constructed to benefit mainly one of these functions and should have minimal effects on the other functions of the river. For example, side channels are constructed to increase the ecological value of the river but side channels generally cause aggradation in the navigation channel and thereby affect the navigational function of the river. Better insight into the bed level changes that result from such interventions can help to improve their design such that the effect on conflicting river functions is mitigated.
Key goals: Fundamental understanding Integrated management
Innovative components
Several analytical and numerical models exist that can be used to estimate the river bed level changes as a result of interventions (top left side of the figure). However, field measurements of such development are rare. We use a large dataset to estimate the development of several types of interventions and characterize their bed level variation (top right side of the figure). We apply a method that can distinguish bed level changes that occur at different spatial scales. This allows us to identify the contribution of the interventions to the local bed changes. Second, we study the morphological variation of the river without interventions. This variation occurs as a function of the river’s geometry in combination with the discharge. Combining the morphological effect of the interventions with the morphological variation of the river can result in a more optimized design of river interventions. For example, a side channel locally increases the equilibrium bed level and local narrowing of the floodplain reduces the equilibrium bed level (bottom of the figure). If the side channel is constructed at the correct location, the bed level changes counteract each other.
For whom and where?
- Managers who need to design new river interventions and need to gain insight into the morphological behavior of their river
- Practitioners that want to optimize the design of river interventions.
Data-collection methods: Field survey measurements Historical approach
Temporal scale: 1-10years
Application development and findings
We make an atlas of the bed level dynamics of the river as a function of the discharge. With the atlas, we gain insight into the deposition and scour within the river. The maps can be used to explain the formation of bottlenecks for navigation, to explain the maintenance needs of the river, and to verify morphodynamic models in more detail. In addition, the maps can be used to optimize the location, type, and design of interventions such that their impact on other functions of the river is minimal.
Status for day-to-day practice
We visualized the behavior of the riverbed as a function of the discharge. This atlas gives insight into the “natural” bed-level variation of the river that assists morphodynamic management of multi-functional rivers.
Spatial scale: Channel Reach
Key locations: Netherlands (NL) Rhine River (NL)
List of publications:
Last updated: 23/02/2021
Explore the contact details to get to know more about the researchers, the supervisory team and the organizations that contribute to this project.
Contributing researchers
Pepijn van Denderen
University of Twente
User group
As soon as available, explore the storyline to get to know more about the main methods or prototype tools that were developed within this project.
The fluvial response to flow variations
Insight into the dynamic component can help to manage the river and to design interventions
Pepijn van Denderen
University of Twente
Changes in the equilibrium river profile: The morphological impact of interventions
We propose a new method to study bed level changes in a river
Pepijn van Denderen
University of Twente
Explore the output details for available publications to get a glance of the innovative components and implications to practice as well as the links to supporting datasets.
Project outputs
Disentangling spatial scales of morphological development
The river bed continuously changes on various spatial and temporal scales. Migrating river dunes are an example of local and relatively fast change. At the same time, engineering measures from the last decades cause the river bed to degrade to the present date. To be able to predict the development of the river bed, it is important to distinguish between and disentangle the various spatial and temporal scales.
13/02/2020 by Pepijn van Denderen et al.
Contains: Publication open access
The initial morphological impact of the longitudinal dams
Human interventions can result in changes in the equilibrium profile of rivers. It is difficult to identify the bed level changes that result from river interventions due to the various causes of bed level changes. Using wavelet filtering, we are able to isolate the effect of river interventions based on the length scale over which they occur. The method presented here can aid in verifying model results. In addition, it can be used to estimate bed level changes that occur over various spatial scales.
13/02/2020 by Pepijn van Denderen et al.
Contains: Publication open access
Laying bare systemic river bed changes in the river Rhine
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.
11/02/2021 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
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
Take a look to the dissemination efforts and application experiences which are available in the news items and blogs.
News
How much sand does a secondary channel yield?
10/03/2020 by Pepijn van Denderen
The construction of a secondary channel creates an additional habitat for life in the river. But such a secondary channel also causes the flow...
We joined efforts with the following projects to support with each other's expertise and experience the development of the new methods or prototype tools.
Anything to ask or share?
About usWe would like to learn from your experiences and questions to take our knowledge further into practice in the Netherlands and abroad. Your feedback will help us to find out about your interests and how useful the information provided was to you.