Wadden Region

The entire Wadden Sea, from Den Helder to Esbjerg, has been designated as a UNESCO World Heritage site. It ranks among the world’s most important wetlands and has unique natural values. The area is also of major importance in terms of flood risk management. The outer deltas, the Wadden islands, the flats and the salt marshes together protect the northern coast of the Netherlands.

The point of departure in the Preferential Strategy regarding flood protection of the the Wadden Region is that the important values of the Wadden Region are maintained by opting for measures that are as ecological as possible. The focus in the years ahead will be on fleshing out the strategy. The region will explore opportunities for an integrated approach to the measures. The Delta Decisions and the Decision on Sand constitute the framework in this regard.

Schiermonnikoog

Tasking

The long intertidal zone in the shallow Wadden Sea (mudflats, salt marshes, and channels) constitutes a buffer against the high waves of the North Sea. Without this buffer, the flood defences along the mainland and island shores would have to be stronger and higher. The intertidal zone of the Wadden Sea requires additional sand in order to adapt to the rising sea level. If the rise in sea level accelerates, more sand will be needed, and a situation may arise in which the intertidal zone can no longer keep pace with the rising sea level, which will reduce its buffering effect.

In addition, a stretch of flood defences along the mainland and island shores of the Wadden Sea spanning approx. 100 kilometres fails to provide the statutory level of protection. Moreover, some sections of the flood defences need to provide a higher level of protection, in particular with a view to the key role that the province of Groningen plays in gas extraction and (inter)national gas transport. A final important issue is rendering the dykes in Groningen earthquake-proof.

Preferential Strategy with three elaborations

A Preferential Strategy has been drawn up for the Wadden Region, comprising three elaborations.

Sand

The aim of the Preferential Strategy is for the intertidal zone to continue to keep pace with the rise in sea level. The current sea level scenarios seem to indicate that, in terms of flood protection, no sand replenishment will be required until 2100, neither in the Wadden Sea itself nor in the Eems-Dollard and its estuary. The system is capable of adapting to seabed subsidence and the rising sea level. Nor is intervention desirable in terms of ecological value. For the time being, sand replenishment along the North Sea coast of the Wadden Islands (on the coastal base) and possibly on the outer deltas will suffice. Pilots such as the Sand Replenishment pilot being conducted on the outer delta of the Ameland tidal inlet (see DP Coast) and monitoring programmes will show whether the sand will be transferred to the mudflats and salt marshes of the Wadden Sea naturally, and in good time (“learning while working”). The pilots and monitoring programmes are implemented under the Coastal Genesis 2.0 research programme launched by Rijkswaterstaat, which provides insight into the operation and future changes of the sand system.

Regular coastal management involving sand deposits is proceeding as scheduled. In 2017, the channel margin replenishment off the island of Ameland was completed. A similar replenishment off the island of Vlieland is in progress. The effectiveness of the sand deposits is being monitored.

Dykes

With respect to dyke improvements, the Preferential Strategy sets out an area-based and integrated approach. This is substantiated by having modifications to the flood defences tie in with area developments and by creating added value for functions such as nature, leisure activities, and the regional economy.

Innovative dyke concepts

Along the mainland shoreline, added value for the nature, leisure activities, and regional economy functions can be created by implementing innovative dyke concepts, such as wide green dykes, multi-functional dykes, and dykes that can withstand overtopping. The three district water boards, Wetterskip Fryslân, Noorderzijlvest, and Hunze en Aa’s are examining these innovative flood defence concepts in pilots conducted within the Wadden Sea dykes General Exploration.

The Noorderzijlvest district water board is already implementing innovative dyke concepts in the Eemshaven-Delfzijl dyke improvement section. The dyke improvements set out in the Flood Protection Programme are on schedule. The Eemshaven-Delfzijl dyke improvement is underway and will be completed by the end of 2019. Potential solutions for the Vlieland dyke improvement are being developed.

Wadden Islands

In principle, the Preferential Strategy encompasses the same building blocks for each of the Wadden Islands: sand replenishment, dynamic coastal management, salt-marsh development, innovative dyke concepts, growing along (re-distribution of sand), habitation outside the dykes, infrastructure outside the dykes, disaster management, and freshwater supply. These aspects are inter-related. Ergo, an integrated approach to flood risk management would seem obvious, yet each of the islands calls for an individual strategy because the inter-relation between the building blocks may differ from one island to the next.

Spatial adaptation 

Spatial adaptation in the Wadden Region involves the territory covered by the Rhine North / Nedereems Regional Consultation Committee, as the Wadden Region Delta Programme only covers the coastal municipalities along the Wadden Sea mainland and the Wadden Island municipalities. For this reason, spatial adaptation in the Wadden Region (all the municipalities) is addressed by the Rhine North / Nedereems Regional Consultation Committee.
The spatial adaptation strategy pursued in the Wadden Region is explained elsewhere on this web site.

In 2017, the Frisian Administrative Water Chain Agreement working region initiated climate stress tests regarding waterlogging and urban heat in all the municipalities in the Frisian section of the Wadden Region, including the Wadden Islands. The results will become available in 2018.

Delta Programme 2019

Read about the progress made in the Wadden Region in Delta Programme 2019.

Tasking

The long intertidal zone in the shallow Wadden Sea (mudflats, salt marshes, and channels) constitutes a buffer against the high waves of the North Sea. Without this buffer, the flood defences along the mainland and island shores would have to be stronger and higher. Currently, the intertidal zone of the Wadden Sea already requires additional sand because of the rising sea level. If the rise in sea level accelerates, the intertidal zone may no longer be able to keep pace and the buffering effect will be reduced.

In addition, the some one-hundred-kilometre long stretch of flood defences along the mainland and island shores of the Wadden Sea does not provide the desired level of protection. Moreover, some sections of the flood defences need to provide a higher level of protection due to the key role that the northern part of Groningen plays in gas extraction and (inter)national gas transport. A final important issue is rendering the dykes in Groningen earthquake-proof.

Preferential strategy with three elaborations

A preferential strategy has been drawn up for the Wadden Region, comprising three elaborations.

Sand

The aim of the preferential strategy is for the intertidal zone to continue to grow along with the rise in sea level. This is achieved by sand replenishment. It appears that, in terms of flood protection, until 2100 no sand replenishment will be required, neither in the Wadden Sea itself nor in the Eems-Dollard and its estuary. Nor is this desirable in terms of ecological value. For the time being, sand replenishment along the North Sea coast of the Wadden Islands (on the coastal base) and possibly on the outer deltas will suffice. Pilots and monitoring (“learning while working”) will show whether the sand will be transferred to the mudflats and salt marshes of the Wadden Sea naturally, and in good time. This is done in the context of the Coastal Genesis 2.0 research programme launched by Rijkswaterstaat, which provides insight into the operation and future changes of the sand system.

Dykes

The preferential strategy for dyke improvement involves an area-based and integrated approach. The focus is on modifying flood defences in line with area developments, and creating added value for functions like Nature, recreation, and the regional economy. Almost everywhere along the mainland shoreline, this can be achieved by implementing innovative dyke concepts, such as wide green dykes, multi-functional dykes, and dykes that can withstand overtopping. The three district water boards, Wetterskip Fryslân, Noorderzijlvest, and Hunze en Aa’s are examining these innovative flood defence concepts in pilots within the Wadden Sea dykes general exploration. The Noorderzijlvest district water board is already implementing innovative dyke concepts in the Eemshaven-Delfzijl dyke improvement section.

Wadden Islands

Together with knowledge institutes and the security regions, Rijkswaterstaat and the island municipalities are working on an integrated flood risk management strategy for each of the Wadden Islands. The strategies deal with sand replenishment management, dynamic coastal management, salt-marsh development, innovative dyke concepts, and disaster management. The potential impact of a flood on the areas outside the dykes will be reduced by explicitly taking flood probabilities into account in spatial (re)developments. The collaborating islands and the security region will bear primary responsibility for the execution of the strategies.

Collaboration in the implementation

Within the Delta Programme, the implementation of measures in the Wadden Region is coordinated in the Wadden Region Delta Programme Administrative Consultative Body / Regional Consultation Committee on the Coast In addition, we are seeking to strengthen our ties with other organisations in the Wadden Region in order to examine where we can join forces and intensify our collaboration.