Important insights and recommendations
According to Jana, the key insight is that there is a negative sediment budget. “There is a negative sediment budget, with annual net loss of sediment from the channels. This is because dredging has increased dramatically over the last 40 years and because, partly due to the closure of the Haringvliet, we have a very uneven sediment distribution. The sediment collects to the north where the harbors are; exactly where we don’t want it. The river bottom is eroding rapidly and getting deep holes. That’s very dangerous.”
Measuring, monitoring and modeling are key recommendations, according to Jana. Jana explains what “the three M’s” mean: ”First of all, we need to measure more. We do not yet have enough grip on the amount of sediment during tidal cycles. As a result, it is very difficult to quantify how much sand and mud is actually coming in.” Monitoring is the next recommendation, according to Jana: ”Monitoring applies to the longer term, for example by making scans of the bottom level.” In the Rhine-Meuse region, many complex issues interact, which is why the current models need to be improved, according to Jana. Jana: “Getting the complexity of the delta into our models will probably take another 10 or even 20 years. They could well use an update: sometimes we are working with models from the 1980s.”
Port of Rotterdam during sunset
A system as a whole
Jana speaks of a ‘ripple effect’. The entire system is interconnected. As an example, Jana cites the Port of Rotterdam. “The Port of Rotterdam manages the new waterway and the port area. That has an effect on the canals and therefore on the people living in the Haringvliet or near the Biesbos.” The connection also manifests itself through other human activities in the river. According to Jana, we dredge more in the Rhine than the busiest ports in the world. ”Dredging has consequences. We see those not where we dredge, but in other locations. If you have economic benefits from dredging you should also be willing to spend money on protecting the river.”
An extended collaboration with Rivers2Morrow
Jana experiences a fine collaboration within Rivers2Morrow for several reasons. Community is the common thread in this. She likes that everyone contributes to a sustainable future for the river and delta system, but the close-knit community is also a big advantage for Jana: “It’s a nice community and we support each other.” And it shows, as she will soon start fieldwork for her follow-up research.
About her new research, Jana says the following: ”We found that there is a nonlinear spatial decrease in sediment. More sediment is coming from the mountains, but it does not reach the delta. Toward the end of the basin and toward the Netherlands, the decline is more severe. ”I am going to do field work in September to trace where the sediment is going in the Necker, Rhine and Moselle rivers. But before I start I have to take driving lessons to drive on this side of the road!”
Related organisations
Rijkswaterstaat
Utrecht University
Related projects
Last modified: 26/09/2023