ROOM FOR THE WAAL

Between the cities of Nijmegen and Lent, the Waal river makes a sharp bend. The winter bed is very narrow at this point in the river. During extreme high water levels the location acts as a bottleneck, making it difficult for water to drain away. The project Room for the Waal has solved this problem by moving the dyke at Lent 350 meters land inwards. An ancillary channel is dredged in the flood plain to help drain the river during extremely high water. This in turn creates better flood protection for the area behind the dyke.

Hydrological solution

The extreme flooding of 1993 and 1995 made it clear that the River Waal is too narrow to drain away large volumes of water. The problem is especially acute near the city of Nijmegen, where the river is trapped in a narrow winter bed between the dykes. In order to be able to drain away high water, the river needed more space at this point. Together with the municipality of Nijmegen and it's residents. Rijkswaterstaat decided to move the dyke landwards near Lent, on the north bank of the river.

Radical and sustainable

Repositioning a dyke is a very radical but also effective and sustainable measure to better protect the watershed against floods. In extreme circumstances, it can even facilitate a reduction in water levels of around 35 centimetres. Moreover, the measure provided an impetus for making major improvements to the city of Nijmegen’s spatial quality, as it has created an island in the Waal, a unique river park in the heart of the city. With the island and the ancillary channel, Nijmegen has been given an entirely new landscape with opportunities for recreation and new urban development.

Room for an ancillary channel

Within the project Room for the Waal, the relocation of the dyke is combined with the construction of an ancillary channel in the widened floodplain. During high water, the water in this channel will flow along with the river. Between December 2012 and the autumn of 2015, workers have dredged the sand and gravel. The channel, three kilometres long and five metres deep, prevents the river from rising too much, and will therefore make an important contribution to protecting the river’s floodplain.

City island and unique river park

Relocating the dyke and dredging an ancillary channel has created a long island in the Waal. Most houses on the river side of the dyke could remain in place. The Island is connected with Nijmegen-Noord  through three bridges: two new bridges and an extension of the Waal bridge. These bridges facilitate new urban development on the island.

Room for the Wall required a major alteration to the area. Not only had the dyke to be relocated and new flood control measures to be created, but the island and the ancillary channel together has formed a unique river park. A 1.6 km long slanted quayside forms the new flood control, together with the green banks on the east side.

Nijmegen embraces the Waal

The Room for the Waal project is one of the projects along the river Waal that will ensure that the river water can flow quicker to the sea. Room for the Waal results in several major changes to the appearance of the city of Nijmegen. The municipal government has taken the opportunity to use the necessary flood control improvements for a major development of the area. In addition to the relocation of the dyke near Lent, the project included the construction of the city bridge De Oversteek, development of the central area De Citadel in Nijmegen-Noord, the transformation of an industrial park in Nijmegen-West into the residential neighbourhood Waalfront, and a facelift for the Waal quay and surrounding area. An entirely new neighbourhood is also being built on the northern bank: de Waalsprong. For combining work on water safety and urban development, the project won the Waterfront Center Award in New York in 2011. Many international delegations visit the prestige project each year: from experts in the field of water safety from America or Cambodia, to delegations of journalists from the New York Times, Al Jazeera Balkans and the China Times.

Nature preservation and explosives survey

The Room for the Waal project lies in an area with a violent military history. In 1944, Operation Market Garden took place in the area, and reminders of World War II - including explosives - can be found everywhere just a few centimetres under ground. Researchers conducted a thorough explosives survey before the builders started digging.

In the preparatory phase of the project, researchers also looked for protected plants or animals living in the project area. The contractor drew up ecological work plans describing how the work should take protected nature in the area into consideration.

ROOM FOR THE WAAL IN FACTS AND FIGURES

Room for the Waal in facts and figures The winter bed of the Waal between Nijmegen and Lent is very narrow. During extreme high water levels, the location acts as a bottleneck, making it difficult for water to drain away. The project Room for the Waal will solve this problem by moving the dyke at Lent 350 meters towards the hinterland. An ancillary channel will be dredged in the flood plain to help drain the river during extremely high water. This will in turn offer better flood protection for the area behind the dyke.

 

Activities

In Room for the Waal, 5 million m3 of sand and gravel were dredged to build:

  • dykes
  • an island
  • an ancillary channel
  • new flood control measures

Effect

  • a reduction of water levels on the Waal by up to 35 cm

Partners

  • City of Nijmegen (project coordinator)
  • Rijkswaterstaat
  • Rivierenland Water Authority
  • Province of Gelderland