The Rhine is not only the setting for many legends, it is also an immensely important traffic artery – and one with bottlenecks. They should be eliminated, not simply in the complex river ecosystem.
What happens on a large scale at the “Jungferngrund” shoal in the Middle Rhine is simulated on a small scale around 160 kilometers south in a hall in Karlsruhe. There, at the Federal Institute for Hydraulic Engineering (BAW), the river passage has been recreated in a reduced size.
The model is intended to help ensure that the huge project of a consistently greater channel depth in the river valley, which has been planned for decades, is implemented in the best possible way – in the best possible way for shipping and nature, as BAW head Christoph Heinzelmann explains.
Officially, the project is called “unloading optimization of the shipping channels on the Middle Rhine”. The Federal Transport Infrastructure Plan 2030 classifies it as urgent. According to Federal Transport Minister Volker Wissing (FDP), who was once also Transport Minister in Rhineland-Palatinate, the project has “outstanding cross-border significance”.
Companies like BASF have already taken their own measures
As expected, the project has met with approval from the business community. A project advisory board with representatives from Hesse and Rhineland-Palatinate is also involved. In Hesse, the Environment and Economics Ministry are in favor of including the project in the federal approval acceleration law. This is intended to make lengthy planning and approval procedures faster. The ministries pointed out that the economic damage caused by the low water levels in 2018 amounted to five billion euros.
At the chemical giant BASF, with its headquarters in Ludwigshafen am Rhein, the financial impact of the low water in 2018 amounted to 250 million euros, according to the company. Since then, BASF has taken action. With the Federal Institute of Hydrology, an early warning system for low water was created, and more emphasis is being placed on ships suitable for low water and alternative modes of transport. And yet, according to BASF, 40 percent of the transport volume is still handled by ship.
With regard to the fairway construction project, BASF announced: “Unfortunately, the implementation of this extremely important project has been significantly delayed due to a lengthy approval process and a lack of personnel in the responsible authorities.” Federal Transport Minister Wissing refers to the so-called acceleration commission he set up. Thanks to her, a broad-based job offensive was launched to strengthen the project team with engineers and technicians. The processes within the project have been optimized “in order to best meet the highly complex questions in the area of tension between ecology and economy.”
Criticism from conservationists
The project is controversial among conservationists. A position paper from the Nature Conservation Association (NABU) states that a greater unloading depth promotes “oversized ship units at the expense of smaller, better-adapted ships.” The development of the Rhine in the context of climate change is not sufficiently taken into account. Especially when the water is low, life in the Rhine is restricted even more to the shipping channel. The areas with shallow water that are important as habitats would be increasingly disconnected or lost.
To ensure that something like this doesn’t happen, the Rhine Waterways and Shipping Authority commissioned the BAW years ago to conduct research to lay the foundations for legally secure planning that balances interests. The Rhine project started at the BAW at the end of 2015, as Andreas Schmidt, head of the inland hydraulic engineering department, explains. It’s about the section from Budenheim near Mainz to St. Goar. According to the Federal Waterways and Shipping Administration (WSV), around 50,000 freight ships (as of 2021) travel there with almost 60 million tons of cargo. Forecasts see an increase to more than 75 million tonnes in the coming years.
Inland shipping association speaks of a “real bottleneck”
However, the consistently guaranteed fairway depth there is only 1.90 meters below the equivalent water level – a low water level that is only reached or fallen below on around 20 days per year. Upstream and downstream it is 2.10 meters, i.e. 20 centimeters more. That doesn’t sound like much, but an additional 20 centimeters would allow up to 200 tons more cargo per ship, says Thorsten Hüsener from the BAW Middle Rhine project team.
The Federal Association of German Inland Shipping calls the Middle Rhine a “real bottleneck”. With unloading optimization, transports would be easier to plan and carry out, even at low water levels. “This is important because raw material-intensive industrial locations rely on reliable supplies from inland shipping.”
“No two sections of the river are the same”
Numerous shoals are to blame for the shallower interior depth. The unloading optimization project focuses on the six most critical areas, including the Jungferngrund near Oberwesel, which was recreated in Karlsruhe. The major project is intended to bring the fairway depth in the Rhine section to 2.10 meters throughout – with interventions that are as selective and environmentally friendly as possible and that must not worsen the level of flood protection, as Sven Wurms, head of the project at BAW, explains. “There are only very individual solutions,” says Hüsener. “No two sections of the river are the same.”
The BAW uses computer models and the Rhine model to see where sediments are carried into the channel by the current. It is then examined how, for example, a higher flow speed can be achieved or how the sediment transport can be controlled. The construction of groynes, structures projecting across the river, longitudinal structures, sills on the river bottom or the filling of scours, depressions in the river bottom are conceivable. In some cases, selective milling of rock will also be necessary.
Jungferngrund as a special challenge
At the Jungferngrund with a gravel bank of the same name and a rocky islet called Tauber Werth, the Rhine makes a 90-degree curve. Ships need a fairly wide channel for their maneuvers, and the current conditions are complex. The gravel bank as an important habitat and the tributary of the Rhine must not be damaged, as Wurms explains. And so all possible variants are recreated on the Rhine model on a scale of 1:60 in length and 1:50 in height. Instead of sediment, plastic granules are transported by the model flow. Conceivable hydraulic structures are installed and tested to scale.
For BAW boss Heinzelmann, the search for such solutions that take many factors into account is almost “squaring the circle”. This makes it understandable why the project is likely to take many years – not least because of the time-consuming planning approval procedures that are still pending. The Rhine model in Karlsruhe is likely to remain in place for a long time, and the BAW should continue to evaluate the measures taken even after the construction work.
Source: Stern
