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Kruibeke Bazel Rupelmonde (Belgium): a controlled flood area for flood safety and nature protection

Kruibeke Bazel Rupelmonde (Belgium): a controlled flood area for flood safety and nature protection

The Kruikeke Bazel Rupelmonde (KBR) Controlled Flood Area (CFA) is a key component of the Belgian Sigma Plan for the Scheldt Estuary. The Sigma Plan is an integrated flood protection plan that combines dykes, seawalls and flood areas to protect approximately 20,000 hectares of land from flooding.

Within the Sigma Plan, the KBR site is the most important Controlled Flood Area, and it is projected to reduce flood risks along the Scheldt Estuary by five times. To create the KBR area, works were carried out to open three contiguous polders (areas of reclaimed land) – the Kruibeke, Bazel and Rupelmonde Polders – to controlled tidal action. Construction started soon after 2000 and in late 2014 it was nearing completion: the final step is the disputed move of an industrial pipeline to allow the new, inner dike to be closed and the CFA to become operational.

Case Study Description


The KBR CFA is a keystone project within the Sigma plan and its largest CFA. The Sigma Plan was designed in response to the storm surge disaster of 1976. During this storm, a dike broke at Ruisbroek, upstream from the KBR site, flooding this town and surrounding lands and requiring the evacuation of more than 2000 people. Due to climate change, such extreme weather events are expected to occur more frequently in coming decades. Measurements already show that the occurrence of storm surge floods as measured at Antwerp have increased significantly since the 1950s. The KBR CFA will provide a large storage area for water during storm surge events, thereby reducing the risks of floods along the Scheldt estuary.


The primary objective of the KBR Controlled Flood Area is to reduce flood risks along the Scheldt and its main tributaries, including in the perspective of climate change and sea-level rise. The KBR CFA should by itself increase current the protection level from floods occurring once every 70 years to once every 350 years. With the addition of ongoing and future Sigma Plan projects, the minimum level of flood protection throughout the Scheldt estuary will be improved further so that flood events are projected to occur only once every 1000 years, taking into account a sea level rise of 25cm by 2050.

The secondary objective of the KBR is to provide nature compensation for the expansion of the Port of Antwerp Harbour and for large infrastructure works taking place in the Scheldt Estuary: the site’s nature compensation area includes 150 hectares of bird meadow area for works related to the port’s Deurganck Dock and 300 hectares of tidal marshland for Scheldt infrastructure works.


The Kruikeke Bazel Rupelmonde (KBR) Controlled Flood Area was created by lowering the height of the former flood protection dykes along the Scheldt and constructing new dykes further inland at the appropriate flood protection height (called the Sigma height). As of mid-2014, the new inland dykes were near completion with only a small gap still to be constructed. The outer dykes have already been lowered to serve as overflow dykes, though in places some further reductions are planned. Once the area is put into operation, it is expected that the exceptional tides (‘leap’ or ‘spring’ tides) and storm surges will overflow the outer dykes an average of once or twice a year.

The KBR site will provide a major contribution to flood safety along the Scheldt estuary due to its large size, 600 hectares, its strategic location and the low level of the land, ensuring a large water storage capacity. The KBR controlled flood area consists of what were originally three separate, contiguous polders (areas of reclaimed land), the Kruibeke, Bazel and Rupelmonde Polders. These polders were used predominantly for agricultural and recreational purposes such as fish ponds. While these functions could be conserved to a large degree within a controlled flooding area, it was instead decided to convert the area into a nature area as compensation for areas affected by port expansion and work in the Scheldt River. This choice to develop nature within the CFA reflects the integrated approach of the Sigma Plan, which combines flood protection and nature protection.

Already prior to the project, the three Polders were designated as Special Protection Zones under the Habitats Directive, based in particular on the presence of priority habitats of ‘remaining relict woods on alluvial grounds’. Furthermore, with the project the Polders were indicated as protected under the Birds Directive. To create the required compensation for natural areas affected by the Port of Antwerp, 300 hectares of tidal marshes, 150 hectares of meadow bird area and 91.9 hectares of forest were planned within the Controlled Flood Area.

For the purpose of creating tidal marshes, several weirs have been inserted in the outer dyke to allow a controlled tide within the CFA once the inland dyke is finalised. The system allows water from the Scheldt to flow into the area through high weirs during high tide and exit the area during low tide through low weirs. The high weirs are important as they allow the effects of high and neap tides to occur within the KBR CFA. Furthermore, the combination of outlet and inlet weirs allows for a regular exchange of organisms and nutrients between the Controlled Flood Area and the Scheldt. One low weir will be kept open on a nearly permanent basis to allow a continual exchange of water between the Scheldt and the Kruibeekse Creek, to support fish migration. The weirs are also essential for removing excess water from the CFA after storm surge events that overtop the outer dykes (and they can be used prior to an expected storm surge event in order to maximize the water catchment capacity of the CFA).

Other natural areas within the CFA are woods and meadow bird areas. As of mid-2014, the meadow bird areas are awaiting a management regime that will ensure that the vegetation remains hospitable to nesting birds. The woods provide compensation for forest areas due to the construction of the inland dyke.

A number of works just outside of the KBR CFA have also been undertaken, including the creation of a small area of depoldered land along the Scheldt River just in front of the outer dyke of the CFA and two water catchment areas on the landward side of the inner dykes. The depoldered area has been exposed fully to the tide as dyke protection has been moved further inland, creating a tidal wetland.  The two catchment areas were created to store water from the creeks that during normal operation flow through the CFA. During storm surge events, the creeks will not be able to flow into the CFA as the weirs through which the creeks usually flow will be closed, and these catchment areas were built to temporarily store their water. The Northern catchment area has been developed into a recreational area with several fish ponds and a walking path.

In addition, the project has integrated recreational functions throughout the site, including paths for hiking and biking, educational signposts, an observation tower and recreational fishing opportunities.


Case mainly developed and implemented because of other policy objectives, but with significant consideration of CCA aspects

Additional Details

Stakeholder Participation

Stakeholder participation has been an essential part of the KBR project. Local opposition started after the project was announced in 1977 as part of the first Sigma Plan, leading to many years of delay. By the end of the last century, while all other original Sigma Plan projects were already completed, work on the KBR CFA had not yet begun. In 1998 a newspaper headline characterised the opposition position as “Wie de Polder Raakt, zal storm oogsten” (i.e. “who touches the polder, will harvest a storm”). Opposition arose from safety concerns expressed by the Kruibeke municipal government, concerns from environmental NGOs about the zoning plan and resistance from farmers and fishing pond owners in the KBR site who did not wish to be expropriated. Protests against the project were organized every Tuesday for several years.

To address this significant opposition, the Flanders government gave extra attention to stakeholder relations and project communication. Attention was directed at specific stakeholder groups including: farmers, nature enthusiasts, municipalities and local residents. Efforts were made to nurture relationships with these stakeholder groups and to achieve broader support from Kruibeke residents by providing them steady updates on the project. Over time the project managed to garner stakeholder support and (following legal action) to expropriate nearly all the land within the polders. Local citizen support was improved through the integration of recreational opportunities for local citizens and others as well as steps to address specific project concerns. The recreational opportunities were also considered to potentially offer new business opportunities through increased tourism. By 2014, local support had increased following changes in the municipal government.

In this process, the designation of the site as a nature compensation area for the Port of Antwerp raised the project’s political profile and provided an impetus to reach an agreement and begin work in 2001.

In late 2014, while nearly all local public and stakeholder issues had been resolved and the project was near completion, one issue continued to block completion. Several pipelines that ran through the polders have had to be rerouted in order to finish the dyke works. Under a 2004 Royal Decree, the owners of the pipelines were required to pay for these works themselves. While three of the pipeline owners rerouted their pipelines, one multinational company has refused to pay for the rerouting of their industrial pipelines, thereby delaying completion of the inner dyke. The Flemish government has initiated legal procedures against this company. Once a resolution can be found, the last piece of dyke can be constructed and the area can become operational.

Success and Limiting Factors

Main success factors include:

  • The project creates a large integrated and multi-functional area that will provide flood safety, natural habitats and recreational space.
  • A lengthy process of communication and relationship building with local communities and stakeholders helped to reverse much of the opposition to the project. Communication emphasised the project’s functions for local safety and also for recreation.
  • Linking the project to compensation for natural areas affected by the port helped to raise its political profile.

Despite these elements, it should be noted that both political and legal processes, including the expropriation of private land, have been lengthy, with close to 40 years elapsing between the initial proposal and its (near) completion.

Costs and Benefits

The budget for the development of the KBR CFA was 100 million, and with the project nearing completition it remains within budget. Approximately three-quarters of the budget was used for studies and construction and one-quarter for expropriating landowners. To carry out the project, more than 100 separate contracts were awarded. For more information about costs and benefits, please see the Sigma Plan case study.

The nature compensation projects that are a central element of the KBR project are linked to the EU Habitats and Birds Directives. The construction of Deurganck Dock in the Port of Antwerp required the compensation of 150 hectares of bird meadow area, while other infrastructural works related to the Antwerp harbour required the compensation of 300 hectares of natural tidal nature areas within the KBR CFA. The compensation works in the KBR CFA related to the Deurganck Dock were mandated by the Flemish Parliament in an Emergency Decree of 14 December 2001.

Implementation Time

The project was initiated in 1977 and is near completion in 2014.

Life Time

No specific lifetime identified; the area will need regular upkeep and maintenance, with which it will become a permanent part of the landscape.

Reference Information


Stefaan Nollet
Project Engineer
Waterwegen en Zeekanaal NV – Department Sea Scheldt
Anna Bijnsgebouw - Lange Kievitstraat 111-113 bus 44 - 2018 Antwerpen
Phone: +32 (0) 3 224 67 32

Wim Dauwe
Head of unit
Waterwegen en Zeekanaal NV – Department Sea Scheldt
Anna Bijnsgebouw - Lange Kievitstraat 111-113 bus 44 - 2018 Antwerpen
Phone: +32 (0)

EC DG ENV Study "Sharing of Best Practices on Integrated Coastal Management (ICM) in a Context of Adaptation to Climate Change in Coastal Areas"

Published in Climate ADAPT Jun 07 2016   -   Last Modified in Climate ADAPT Mar 04 2020

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