In August 2015, Rees in the Lower Rhine region in the district of Kleve completed the construction of the Rees flood channel. It took 15 years of planning and development, and approximately six years of construction. Honorable guests at the inauguration of this landmark construction project included, among other, the NRW Environment Minister, Johannes Remmel, and Enak Ferlemann, State Secretary at the Federal Ministry of Transport and Digital Infrastructure.
The project was particularly praised for its successful balancing of the needs of inland waterway transport with nature conservation and tourism requirements.
The Rees flood channel evidenced the benefits arising from such delicate equilibrium already by mid-January 2015, as flood situations result in the complete inundation of the flood channel area. Even if construction works were delayed by a good week for this very reason, employees of the Water and Shipping Office Duisburg-Rhein were thrilled to see the flood channel working as planned, while the flood pressure on Rees ramparts dropped significantly.
The flood channel construction started in 2009, with extensive earth movements taking the lion's share of overall work. In a massive effort, about 2.1 million cubic meters of topsoil were shifted, a volume nearing that of the Great Pyramid of Egypt.
To protect the embankment and bottom of the flood channel with high water levels, ca. 320,000 square meters were covered after excavation with filter mats, which were filled with quartz sand. Moreover, iGGmat Vmax P550 erosion protection mats were laid above the mean waterline. These three-dimensional, durable mats were developed specifically for use in water engineering. They consist of a base and cover grille made of polypropylene, with a crimped PP grating, and a PP fiber pad in the middle. Further to iGGmat Vmax P550 erosion protection mats, the upper embankment areas were covered using iGGmat Vmax C350 erosion control mats with coconut fiber. Mats were planted either with hydroseeding or reed plants. The nearly 84,000 square meters of iGGmat Vmax P550 and iGGmat Vmax C350 erosion control mats favor the long-term stability of plants, while protecting the planted soil surface against the erosion forces of the Rhine.
Areas exposed to particularly high flow rates were fitted with iGGgab river mattresses, which feature a zinc-coated, repeatedly twisted wire with hexagonal mesh. This is, for example, the case of the area above the ramp, which was created from scratch at the beginning of the construction work in winter 2009/2010. Baskets have a size of 4.0 x 2.0 x 0.3 meters, and are divided into 2.0 x 1.0 meter units. The iGGgab river mattresses were folded on site, installed, and filled with gravel in their final position. Then, gaps left in around 36,000 tons of gravel were silted up with topsoil-substrate mixture. Finally, around 16,000 square meters of advanced reed mats were laid on and secured to silted wire baskets. The resulting reed edge of the mean waterline goes upwards beyond the embankment in a moist tall herb corridor.
A few months after the inauguration, one can proudly say that the Rees flood channel can mitigate flood situations as intended, but also offer an exemplary effort of nature and landscape protection. Not surprisingly, ten lapwing pairs have already settled in the Reeserschanz compensation area. At the same time, the project has managed to secure the navigability of the busiest waterway in Europe.
iGGmat Vmax C350 erosion control blankets at the Rees flood channel