An emphatic appeal to the delta commissioner: come up with a plan

Detailed plans are needed for each region to prepare the Netherlands for the consequences of climate change and accelerated sea level rise. The delta commissioner should take the lead in this, say TU Delft professors Bas Jonkman and Han Meyer in an open letter.

Hydraulic engineering day
Bas Jonkman, professor of water engineering at TU Delft, and Han Meyer, emeritus professor of urban planning at TU Delft, published their open letter to the delta commissioner on the eve of the annual Hydraulic Engineering Day, which takes place on Thursday at the Jaarbeurs in Utrecht. The organization is in the hands of the Royal Institute of Engineering (KIVI).

In recent years, various initiatives have been taken to explore the consequences of sea level rise for our country, such as the start-up of a Knowledge Program for sea level rise. An important goal of this program is to identify possible solutions to deal with this extreme sea level rise.

No shortage of ideas. Since the start of the Delta program in 2009, several designers and engineers have submitted proposals for the adaptation of flood protection and the main water system in the Netherlands.

Delta program

Deltares has a stock of more than 180 of these proposals made, and came to the conclusion that they can be divided into four categories of solutions, each with a core theme:

(1) An open relationship between rivers and seas, with raised dykes along the rivers;

(2) a closed coastline with pumping stations that pump the river water to the sea;

(3) a “seagoing” variant with a new coastline;

(4) a “withdrawal” variant, where the majority of the buildings in the western low-lying parts of the country have been moved to the higher-lying parts of the eastern part of the country.

These four basic variants are beautifully depicted using cartoon drawings. These cartoons have now been shown and explained so often at meetings in or about the Delta program that many can only dream of them.

Strategy by region

However, it is now high time to move from dreams to action. In 2026, the government must make new Delta decisions with a clear preference strategy for each region. If we are to be able to take the necessary large-scale action during this century, the main direction must be crystal clear by 2026.

Previous major adjustments to the Dutch water system, such as the construction of the Nieuwe Waterweg, the Afsluitdijk, the Delta Works and the Room for the River program, show that many decades are involved in the process from defining a main direction, design through to the implementation of concrete plans.

Now is the time to do thorough problem analysis and examine various long-term solutions for technical, economic and social feasibility

If we want to implement the necessary plans after 2050, the main direction of these plans can be determined in 2026, and the concrete implementation will follow in the following decades. This does not mean that a complete plan must already be made for the Netherlands in the year 2100 – that is impossible and undesirable.

Delta Commissioner
The National Delta Program protects our country from floods, ensures sufficient fresh water and contributes to a climate-proof and water-robust design. Various governments and organizations are working on the program under the leadership of the Delta Commissioner. This is the independent government commissioner for the national delta program. Peter Glas has been delta commissioner since 2019

It is true that considerations can be made about which interventions in the water system that, in addition to greater protection against floods, also provide the best opportunities for other important political agendas such as energy transition, nature development and spatial planning. In addition, a timely choice of the main direction will also have a positive influence on the confidence in the risk management in the lower part of the Netherlands and thus on the economic and physical development and the business climate.

Polarization in the delta debate

We are in favor of serious consideration and detailed consideration of the four solutions per region. The idea that a uniform solution direction is necessary and possible for the whole country goes beyond the current reality, which already shows great differences: closed in the case of the IJsselmeer/Afsluitdijk, open in the case of the Western Scheldt, local withdrawal/relocation along the depoldered Hedwigepolder and so on.

Moreover, the four blueprints now even seem to contribute to polarization in the delta debate, see the many discussions in the media and LinkedIn about moving forward (associated with building freezes under the NAP and massive withdrawal) versus protecting everything with ever-higher flood defenses.

The 180 plans and ideas that Deltares has inventoried are largely the work of passionate professionals in their spare time, students and competitions, where competitors received no or minimal cost reimbursement. But it is now important to release a serious budget and to examine solid problem analysis and different options for long-term solutions for each region with teams of researchers, designers and engineers about their technical, economic and social feasibility.

Storm surge barriers will no longer provide safety in the future

In terms of social feasibility, it is important to examine the possible effect of the different options on a spatial, ecological and economic level and to make these the subject of public debate.

A previous study by the Expertise Network for Flood Risk Management (ENW) shows that the first bottlenecks will occur in the Rotterdam-Rijnmond area and the Oosterschelde area. During this century, it is expected that the movable storm surge barriers such as the Maeslantkering and the Oosterscheldekering will approach the end of their design life or will no longer be able to offer the desired functionality or safety. This will certainly be the case if sea levels rise faster.

It’s time to move from dreams to action. If we are to be able to take large-scale action during the century, the main direction must be crystal clear by 2026

The relationship between port, city and water system is decisive for the area near Rotterdam. In recent decades, the port has increasingly moved west and therefore away from the city. Harbor areas in the city center that have become vacant have been used for urban development (housing) and can also be used in the future to, for example, (re)develop nature and restore biodiversity.

Rotterdam Sponge City
What could the future of the Rotterdam region look like, given a sharp rise in sea level? Read more about Rotterdam Sponge City here.

An emphatic appeal to the delta commissioner

The question is how this relationship will develop in the future and what the stakeholders involved (port, city and nature conservation organizations) together see as direction. A solution in the water system can be the key to this. In light of the challenges that lie ahead of us (housing, energy and port conversion, climate adaptation, restoration of biodiversity), it is now time to seriously work on the solutions.

Read in the November issue of The engineer more about hydraulic engineering.

In summary, we strongly appeal to the delta commissioner:

1. Start now with a plan for the second half of this century so that a preferred strategy can be established by 2026.

2. Change from the four national strategies with associated cartoons to the preparation of regional plans by “calculation and drawing”. Set aside a significant budget for this (instead of fleeting design studies) and use the design, thinking and computing power of Dutch engineers, scientists and designers.

3. Starting in the Rotterdam-Rijnmond area, explore alternative strategies how urban development, transformation of the port and interventions in the water system can reinforce each other there.

Text: Bas Jonkman, professor of water engineering at TU Delft, and Han Meyer, emeritus professor of urban planning at TU Delft
Image: Depositphotos

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