University of Twente Student Theses
THe influence of lateral inflow on the water level in the IJssel
Beelen, E.G. (2024) THe influence of lateral inflow on the water level in the IJssel.
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| Abstract: | The Meuse flood in 2021 in the Netherlands was not accurately predicted due to the lack of consideration of lateral inflow in the discharge forecasting. Similar events may occur in other basins and more frequently. In December 2023, the IJssel, a river branch of the Rhine, experienced higher water levels than expected due to high lateral inflows. To improve forecasting, lateral inflow should be considered. Researching its influence on water levels can help to determine if it should be considered. Therefore, the aim of this research is to analyse the influence of lateral inflow on the water level and the shape of the discharge wave in the IJssel. Discharge waves in the Rhine, Oude IJssel and Twentekanaal from the last 30 years were analysed based on their peak discharge, duration and shape. The timing was changed such that the peak of the laterals enter the IJssel at the same time of the peak of the IJssel is at their confluence point, representing the reference timing. The influence of the reference timing on the water level and shape of the discharge wave in the IJssel downstream of the laterals was analysed. The shape of the discharge wave in the IJssel without lateral inflow was altered by adjusting the skewness and width of the discharge wave. The influence of the changed shape on the water levels in the IJssel downstream of the laterals was analysed. The discharge wave analysis showed that the highest and longest discharge waves in the Rhine occurred during high water season (November to April) and the peak discharge and duration showed a linear relation. Conversely, the discharge waves in the Oude IJssel and Twentekanaal also had high peak discharges during low water season and they did not show a linear relation between the peak discharge and duration. Subsequently, the results of the changed timing showed that the timing where the peak discharge of the lateral entered the IJssel at the same time asthe peak discharge in the IJssel resulted in the highest increase in water level. The increase in water level differed per location along the IJssel, from +17 cm at Doesburg to +27 cm at Zutphen and Wijhe. This difference was caused by the amount of lateral inflow that entered the IJssel. At Doesburg only lateral inflow from the Oude IJssel entered the IJssel, while at Zutphen and Wijhe, the Twentekanaal entered the IJssel as well. Additionally, the peak discharge from the Rhine determined the water level in the IJssel and thus the position in the river profile. The changing river profiles along the IJssel influences the change in water level due to lateral inflow. Then, the results of the change in shape of the discharge wave in the IJssel showed that it affects the increase in water level in the IJssel due to lateral inflow. This was mainly a result of a change in total volume of the different shapes of discharge waves which affected the water level in the IJssel. At certain peak discharges, floodplains inundate at some locations along the IJssel, as the river profiles are different. The difference in increase in water level per shape had a maximum of +/- 4 cm, which made the influence of the shape less important than the influence of the timing. Overall, the timing of the lateral inflow caused a higher increase in water level than the shape of the discharge wave in the IJssel. However, the timing that caused the highest increase in water level differs 4 days from the timing that occurred most in historical data. At peak discharges lower than 7,000 m3 /s in the Rhine, the same lateral inflow had larger influence on the water Level in the IJssel. At these discharges, lateral inflow can make a difference for navigation or the timing at when the floodplains inundate. The influence of lateral inflow along the IJssel differed per location due to the differences in river profile. At wider river profiles the influence of lateral inflow wassmaller. It can be concluded that lateral inflow from the Oude IJssel and Twentekanaal can increase the water level in the IJssel, but the amount of increase was dependent on the location along the IJssel and the peak discharge in the Rhine. |
| Item Type: | Essay (Master) |
| Clients: | Rijkswaterstaat-ON, Arnhem, Netherlands |
| Faculty: | ET: Engineering Technology |
| Subject: | 56 civil engineering |
| Programme: | Civil Engineering and Management MSc (60026) |
| Link to this item: | https://purl.utwente.nl/essays/101578 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
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