In this project we gain insight on the large-scale river response to human intervention and climate change. We see that the river is still adjusting to past river normalizations (18th-20th) through changes in the channel slope, which lead to bed incision. This response is more prominent than the response to climate change scenarios.
Motivation and Practical Challenge
River bed erosion is a critical issue for river managers, as it affects navigation, flood safety and ecology. Understanding why erosion occurs and how it may develop is therefore crucial to ensure that all the river functions can be fulfilled.
In the lower Rhine River the channel bed erodes over hundreds of kilometers in response to past and current human intervention (e.g. normalization works), and to climate change, which alters river discharge and sea level.
While river bed incision and aggradation are particularly problematic at some specific locations (e.g., around fixed beds like Nijmegen, Sint Andries or Spijk), we need to better understand their large-scale dynamics, as these dynamics provide answers to local problems. Understanding these dynamics is also crucial to ensure that future river intervention works with the river instead of against it. While the study focuses on the lower Rhine River, the methods are applicable to engineered rivers in general.
We have three main questions:
- How has the lower Rhine River responded to past human intervention, in terms of bed level change and bed surface grain size change?
- How does the lower Rhine River respond to different climate change scenarios, and how does this response compare to the response to past human intervention?
- How does the lower Rhine River respond to future scenarios of human intervention, and how does this add up to the ongoing response?
- We have investigated channel response to past human intervention by analyzing long records (1920-2020) of field data on bed elevation and bed surface grain size, as well as historical records of human intervention.
- We have developed a modeling framework to assess large-scale channel response to human intervention and climate change.
- We have created a highly schematized 1D numerical model of the lower Rhine River, and calibrated it such that it satisfactorily represents multi-decadal channel response, in terms of bed level change and bed surface grain size changes.
- We have tested the model for different climate scenarios (i.e., scenarios of climate-related changes to the boundary conditions: water discharge, sediment flux, sea level) and for scenarios of human intervention.
- We have compared channel response to climate change with channel response to human intervention, and we have concluded that the latter is dominant in engineered rivers, such as the lower Rhine River.
Relevant for Whom and Where
This research is relevant for the following user groups:
- River managers and engineers — at initial stages of intervention/river management strategy planning, and to evaluate how local problems (e.g., around fixed layers), are part of larger scale dynamics.
- Researchers – to better understand large-scale channel response in engineered rivers.
Findings and Practical Application
- While river bed erosion is particularly challenging at specific locations (e.g. around fixed beds), it is crucial to understand that it follows much larger scale dynamics.
- River response to human intervention is dominant, more so than river response to climate change.
- Highly schematized, calibrated 1D numerical models are a fast and very useful tool to assess large-scale channel response to climate change and human intervention.
- Different management policies across regions or countries can lead to large differences in channel response. Transboundary river studies are therefore essential.
- Frequent monitoring of the river bed is crucial to understand river dynamics.
Status for Day to Day Practice
Potential users should consider large-scale dynamics even for local intervention/management strategy planning, and keep in mind that it is possible to follow the same modeling framework developed in this project and apply it to any river
Some types of river intervention are inherently two or three-dimensional. While schematized 1D numerical models can provide insight on their effects, 2D studies would help us understand some features such as fixed beds, or bifurcations.
In addition, while some characteristics of the river are intensely and accurately monitored (e.g., water levels), sediment-related measurements (like sediment fluxes or bed surface composition) are much scarcer and uncertain. More sediment-related data collection would help reduce the uncertainty of these studies.
Last modified: 20/12/2022
Claudia Ylla Arbos
Mid-Century Channel Response to Climate Change in the Lower Rhine River
The goal of this study is to assess how channel response to climate- related changes in the river controls compares to channel response due to (future) human intervention, focusing on changes in channel bed elevation, bed slope, and bed surface grain size over the next century.
13/04/2022 by Claudia Ylla Arbos
Scenarios for Controls of River Response to Climate Change in the Lower Rhine River
We discuss the projected changes of the hydrodynamic river controls over the 21st century, and how they can be transformed into suitable boundary conditions for a schematized model. Here we consider the Lower Rhine River, from Bonn (Germany) to Gorinchem (Netherlands).
11/02/2021 by Claudia Ylla Arbos
Bed level change in the Upper Rhine Delta and Niederrhein
We use bed level data collected since 1926 to assess large scale bed level change in the Upper Rhine Delta and Niederrhein.
10/07/2020 by Claudia Ylla Arbos
Bed level change in the upper Rhine Delta since 1926 and rough extrapolation to 2050
This study constitutes a first step into predicting the long term morphodynamic response of the Upper Rhine- Delta to climate change. The aim is to get deeper insight into past bed level trends and explore options for data-based extrapolation.
01/11/2019 by Claudia Ylla Arbos
Response of the upper Rhine-Meuse delta to climate change and sea-level rise
The Rhine River is the most important inland waterway in Europe, with over 300 million tons of cargo transported annually over its waters (Blom, 2016). The river also serves as a water supply for households, industry and agriculture, evacuates wastewater and is part of several nature conservation areas (Frings et al., 2014). Additionally, its waters create a main ecological corridor and host several hydropower plants (Middelkoop et al., 2001). The proper fulfilment of these functions can be hindered due to human intervention and climate change, which both impact the river morphodynamics.
31/01/2019 by Claudia Ylla Arbos
Effects of climate change on the Dutch Rhine branches
The Dutch are concerned with the consequences of accelerated sea level rise for the coastal protection system. Astrid Blom reminds us that climate change will not only affect the coast but also the rivers. PhD candidate Claudia Ylla Arbos will study these implications in further detail in the research program Rivers2Morrow of the National Research and Innovation Programme on Water and Climate (NKWK), funded by Rijkswaterstaat and DGWB.
01/01/2019 by Claudia Ylla Arbos
Ylla Arbós, C., Schielen, R., Blom, A. (2019). Response of the upper Rhine-Meuse Delta to
climate change and sea-level rise. NCR Days 2019 (p. 116-117). Utrecht.
Ylla Arbós, C., Blom, A., van Vuren, S., & Schielen, R.M.J. (2019). Bed level change in
the upper Rhine Delta since 1926 and rough extrapolation to 2050. Research report. Delft
University of Technology. Delft.
Ylla Arbós, C., Soci, F., Schielen, R., Blom, A. (2019). Aggradation and degradation in the
upper Rhine-Meuse delta in response to climate change. RCEM 2019. Auckland.
Ylla Arbós, C., Schielen, R., Blom, A. (2020). Bed level change in the Upper Rhine Delta
between 1926-2018. Nijmegen.
Ylla Arbós, C., Blom, A., Acevedo Goldaracena, F., van Vuren, S., Schielen, R.M.J. (2020)
Bed level change in the Upper Rhine Delta and Niederrhein. River Flow2020. Delft.
Ylla Arbós, C., Blom, A., Viparelli, E., Reneerkens, M., Frings, R.M., Schielen, R.M.J. (2021). Slope increase and gravel front fading in an incising river. Geophysical Research Letters.
Ylla Arbós, C., Blom, A., Schielen, R.M.J. (2021). Scenarios for Controls of River Response
to Climate Change in the Lower Rhine River. NCR Days 2021.
Ylla Arbós, C., Blom, A., Schielen, R.M.J. (2021). Channel Response of the Lower Rhine
River to Climate Change and Human Intervention over the 21st Century. AGU Fall Meeting
2021, New Orleans.
Ylla Arbós, C., Blom, A., Schielen, R.M.J. (2022). Mid-Century Channel Response to Climate Change in the Lower Rhine River. NCR Days 2022, Delft.
Ylla Arbós, C., Blom, A., Schielen, R.M.J. (2022). Response of the lower Rhine River to
climate change over the period 2010-2050. Proceedings of the River Flow Conference 2022