Delta Programme Commissioner recommends: hold on to Meuse Valley flood protection standards

It is advisable to leave the flood protection standards for the Limburg Meuse Valley, as set down in Delta Programme 2015, as they are. The province of Limburg deserves proper flood protection, as do the other parts of the Netherlands. It is, however, important for the district water board, municipalities, provincial authorities, and Rijkwaterstaat to ensure, in consultation with local residents, that the Meuse dykes have a minimal impact on the environment, and, wherever needed, to look for smart, innovative solutions to have these dykes blend in as well as possible.

This is the conclusion drawn by Delta Programme Commissioner Peter Glas in his advisory report to Minister Van Nieuwenhuizen of Infrastructure and Water Management and to the Meuse Delta Programme Steering Group, on which the parties collaborating on the Delta Programme measures along the River Meuse are represented. "Security and proper protection for all the residents of the Netherlands, including those in Limburg, is our prime consideration. From the perspective of public interest in Limburg and also with a view to climate change, it is important that we preserve the standards at their current level rather than create a status aparte for the province of Limburg. I can imagine the concerns of those living in the vicinity of the River Meuse. In many cases, the flood defence systems encroach deeply upon the environment. That is why it is vitally important for those carrying out the measures in Limburg to continue to consult with local residents, in order to come up with good solutions."

Safety first

The protection standard for most of the Limburg flood defences is 1:100, which means that primary dykes must be sufficiently high and strong to keep the risk of failure below once every 100 years. The Limburg standards thus rank among the lowest within the statutory system of primary flood defences. The province of Limburg now encompasses 45 dyke sections totalling 185 kilometres in length. The decades ahead will see the improvement of sub-standard dykes and the construction of new dyke sections, in order to ensure that by no later than 2050, the people of Limburg will be sufficiently protected and can live and work in the Meuse Valley in safety.

In 2017, the flood protection standards for the Netherlands were anchored in law. The Delta Programme Commissioner was asked for advice following a request from the province of Limburg, submitted in 2018, to amend the flood protection standards on account of the costs and impact of the Limburg dykes. The advisory report is based on a technical study according to which 22 dyke sections in Limburg would qualify for a reconsideration of the flood protection standards, in view of the minor damage to be expected in the event of a flood.

In the purview of his advisory report, the Delta Programme Commissioner has explored all the options for an amendment of the current flood protection standards and mapped out, e.g., the financial, administrative, spatial, and legal ramifications that each of these perspectives would entail. On the basis of the outcomes, the Delta Programme Commissioner has come to the conclusion that the option involving preservation of the current standards would be best, especially considering the possibilities for a tailored approach within the statutory regulations. Actual practice has shown that less invasive dyke designs are feasible, and interesting innovations have been developed that would garner more support, e.g., the glass dyke near Neer and the self-closing flood defence near Steyl.

Lowering standards undesirable

In the opinion of the Delta Programme Commissioner, lowering the standards would be undesirable, as this would leave Limburg with a statistical risk of flooding of once every 30 years rather than once every 100 years.

According to the Delta Programme Commissioner, lowering standards would not mean that the dykes would encroach significantly less on the Limburg landscape, nor that they would save Limburg a substantial sum in costs. The Delta Programme Commissioner relies heavily on the views of the Security Regions involved. They have indicated that lowering the standards would make it extremely difficult to meet the attendant higher requirements regarding resident evacuation. Furthermore, a lower-category standard may affect the possibilities for allowing new developments behind the Meuse dykes. Agreements on lifting the “riverbed status” if a dyke is considered safe under the current standards, were recently set down.

The advisory report now presented by the Delta Programme Commissioner constitutes a building block for the statutory assessment of the flood protection standards in the Netherlands, which is scheduled for 2024.