Closing the open Rijnmond (HSRR03b)
New policy measures may be needed to keep the flood risk in the Rotterdam region within the flood standards during the next century. One of the possible measures is to reinforce the dykes. However, in urban areas the reinforcement of dykes is often socially undesirable and leads to high costs. Therefore, the option was investigated to install a number of moveable high water barriers to the south and east of the urban area, upstream barriers, and a connection between the Lek and the Waal.
The multidisciplinary project examined five variants of the concept Closable Open Rijnmond, including the current situation. It was tested under various climate scenarios looking at the effects on water safety, cost, the impact on shipping and the spatial quality of the region.
Although the concept Closable Open Rijnmond was identified as an option in the report of the Commission Veerman this research put important caveats here. Only in the case of extreme sea level rise the concept seems to have a chance. But also in this case major bottlenecks remain (such as the combined effect of sea level rise and high river discharges). In addition, the regulatory design is very complex and a solution is necessary for the relatively high failure rate of flexible barriers (including the Maeslant barrier with a failure probability of 1: 100).
Other combinations and locations of movable barriers, dams, dike reinforcements' system expansions and forms of water storage in the Southwest Delta are more effective. The results of this study (the project HSRR03B lockable open Rijnmond - Waterfront Rijnmond) have been published in six sub-reports (in Dutch) and an integration report.
Rijcken, Ties (TU Delft-waterbouw) (2010). Afsluitbaar Open Rijnmond - een systeembenadering.