Delta Decision for Flood Risk Management

The protection level is higher in locations where the potential impact is very high, for example if there is a risk of large numbers of casualties, extensive economic damage and/or damage to vital infrastructure of national importance.  

New standards

Between 2015 and 2024, considerable progress was made on the implementation of the Delta Decision for Flood Risk Management. The protection objectives have been formulated as standards - some of them new - for the primary flood defences: the dikes, dunes, dams and storm surge barriers that protect our country against flooding from the sea, the major rivers and the large lakes. These standards were set out in the Water Act (Dutch), and they came into effect on 1 January 2017. The Water Act was merged into the Environment Act on 1 January 2024. 

Assessment of primary defences and dike upgrades 

2017 saw the start of the first National Assessment Round for these primary defences. A set of statutory instruments is available for that purpose. This is a package of agreements and methods for the assessment of the primary defences. That assessment was completed in 2022. In 2023, it became clear that the management authorities believe that more work will be required than previously thought to upgrade our defences. The years to come will be needed to establish a clearer picture of the actual upgrade agenda. It is in any case clear that a majority of primary flood defences do not yet comply with the standards for flood risk management.  

Flood Protection Programme

The Flood Protection Programme (HWBP) was also launched in 2014: this is the largest operational project in the Delta Programme. The twenty-one water authorities and Rijkswaterstaat are working together in the programme on the largest dike upgrade operation since the Delta Works. The goal of the HWBP is for the primary defences to comply with the flood risk management standards by 2050. That work may involve a total of approximately 2,000 kilometres of dikes and more than 400 engineering structures such as locks and pumping stations. A total of 219 kilometres of dike and 138 structures have now been upgraded or declared safe. About 110 dike upgrade projects, representing 887 kilometres of dike and 261 other engineering structures, are planned for 2025-2036.  

Of the approximately 9 million people living behind a primary flood defence in our country, about 80% already had the base level of protection in 2020. By 2029, the percentage of inhabitants with the base level of protection will have increased to about 82%. For more information on the Flood Protection Programme and the upgrade agenda, see this parliamentary letter (Dutch). 

Smart spatial planning and crisis management

The Delta Programme does not focus exclusively on flood prevention. Limiting potential damage and the number of casualties if there is flooding after all is also a responsibility of the government authorities for which the Delta Programme works. The consequences can be mitigated by making smart choices in spatial planning and crisis management. The Working Group on Mitigating the Consequences of Floods issued an advisory document in this respect in 2018. The Delta Programme for Spatial Adaptation works on spatial planning. 

The Steering Group for the Management of Water Crises and Floods (SMWO) improved water crisis management. An Evacuation Module for Large-Scale Floods is now available, including the app and website overstroomik.nl/en. The National Water and Floods Information System (Dutch) (LIWO) provides up-to-date flood information.  

Evaluation of Water Act

In early 2025, the Minister of Infrastructure and Water Management published the evaluation of the Water Act, the Flood Protection Programme subsidy arrangements and the periodical evaluation of the Flood Protection Programme in a Parliamentary Letter (Dutch). 

Markermeer dike upgrade

The operational phase of the latest project in the Second Flood Protection Programme (HWBP-2; the predecessor to the current HWBP) is in full swing. This is the upgrade of the Markermeerdijk Hoorn-Edam-Amsterdam dike over a distance of 31 kilometres. The entire section is expected to be completed by late 2027. At that time, HWBP-2 will have completed the upgrade of 362 kilometres in total. The entire operation is expected to be completed by late 2027.  

Knowledge and research

The knowledge questions about flood risk management are listed in the Knowledge Agenda of the Delta Programme (Dutch). Important knowledge questions concern sea level rise. The final results of the Sea Level Rise Knowledge Programme will be available in 2026. The studies look at the rate of sea level rise from the second half of this century onwards. The research also shows how long the current strategies for flood risk management will be tenable and describes the alternatives to keep the Netherlands safe and liveable in the distant future.  

The Ministry of Infrastructure and Water Management is continuing to improve the tools for assessing and designing primary flood defences on the basis of new insights, in collaboration with the managers of the flood defences.  
The Steering Group for the Management of Water Crises and Floods (SMWO) is enhancing knowledge about crisis management by promoting knowledge exchanges between the organisations involved and conducting pilot projects. The crisis partners share knowledge in the Netherlands Water Management Centre (Dutch). They also exchange knowledge and information with other countries.