Nijmegen

Eiland veur Lent

The city of Nijmegen is located in the Eastern part of the Netherlands close to the German border and stretches across an elevation of 7 to 88 meter. It is the biggest city of the province of Gelderland (168,000 citizens, density of 3,100/ km2). It is located at a bottleneck of the River Waal, an arm of the River Rhine. Whereas the main centre of Nijmegen is located South of the River, Lent, a former village which was annexed by Nijmegen in 1998, is situated North of the River, just as the Waalsprong. The Waalsprong is a Vinex-location[1] with around 11.000 apartments. The Ooijpolder, a nature area, is located in the South-East of Nijmegen.

Flood risk in Nijmegen is mainly fluvial and to a certain degree of pluvial nature. Especially the danger of fluvial flooding is increased due to the city’s location at a bottleneck, where the river width is reduced to 350 meter. During the high river discharges of the River Rhine in 1995, 250.000 inhabitants in the area of Nijmegen needed to be evacuated, because the dikes threatened to collapse but eventually held. This event is seen, nationally, as a big shock.

 

fig1

Figure 1: Map of potentially flooded area (www.risicokaart.nl)

The measures carried out in Nijmegen, that means the dike relocation 350m inland[2] and the implementation of a blue (water carrying) side channel[3] (see figure 2), belong to the strategy of flood defence. That means factual no change occurred, however, the underlying discourse and rationale differs greatly from a traditional dike strengthening approach. The governance differs too. It shifted from a traditional sector-based approach to an integrated governance approach.

 

 

fig2Figure 2: Room for the River measure in Nijmegen[4]

Three hectare on the island will be heightened by two meters, so that it will be 75 cm higher than the existing dike. This area is perceived to be flood-free and will be used as an urban development area for the municipality. Accessibility of the island is ensured due to two ways. (1) The bridge connecting the two sides of the river provides access to the island for emergency services and escape routes for citizens in case of an emergency (F-N) Furthermore, an extra bridge to the island will be constructed. That means flood mitigation measures are also present as well as preparation and response measures.

 

 

[1] Fourth Memorandum Spatial Planning Extra – Vierde Nota Ruimtelijke Ordening Extra; describes the construction of new housing development areas from 1995 to 2005 (Evaluatie Verstedelijking VINEX 1995 tot 2005 ‒ EindrapportMinisterie van VROM (2005).

[2] The new dike will be a green dike with a “hard” flood defence structure – a quay. The quay consists of a concrete wall and below is a seepage protection structure (kuilscherm), which is covered by a soil layer, so that development can be carried out on it (Interview F-N).

[3] The objective of the side channel is to lower the water level in the main river bed. At the upstream end of the side-channel a construction is implemented that shall prevent the accidental entering of ships into the side channel (F-N). The construction of the side channel leads subsequently to the formation of an island in the river.

[4] http://bicycledutch.files.wordpress.com/2014/05/room-for-the-river.jpg)