The limits of the Netherlands’ water system have been reached

Long-term drought, severe storms, and rising sea levels. Without a clear policy, we will eventually find ourselves surrounded by water, without a drop to drink, explain Maarten Kleinhans, Esther Stouthamer and Niko Wanders.

How can we bring our water system back into balance? By investing in more room for rivers; by de-fragmenting land use in the Netherlands to make it easier to adjust water levels; by embedding the ‘Water and Soil Preeminent’ policy in the law as well as in government policy; and by immediately starting to build climate-proof buildings with a required Climate Test. That is how to implement effective policy that can quickly adapt to the latest developments.

1. Room for rivers

The water level of our rivers is rising due to rising sea levels, which prevent rivers from draining into the ocean, and discharge (peaks) increases by more water draining from Belgium and Germany Combined with more extreme rainfall, the rivers therefore need more space to store all the water. Raising or reinforcing dikes may seem to be a solution, but they are by no means effective everywhere. Aside from the massive cost in terms of money, space and landscape quality, raising dikes makes the polders behind them deeper, which in turn makes it more difficult to handle precipitation.

In the western half of the country, making rivers wider is no longer effective due to rising sea levels, because the sea would just intrude farther inland. Moreover, the extreme water level of the Maas River in 2021 shows that it is much too risky to organise the landscape based on today’s weather statistics. These past statistics ignore the new extremes due to climate change, which will be much more severe than in the past few years.

One way to make more room for the rivers is to organise the floodplains as nature reserves and no longer allow permanent housing. That would make the floodplains suitable for storing both extreme precipitation and flood water, to store more fresh water and create more space for nature.

2. Less land fragmentation

Dry summers and increased consumption of freshwater create problems in our water supply. As the water table drops below a critical level, farmers can no longer irrigate their crops, nature areas dry out, and the risk of forest fires increases. To prevent drought, the water table level must rise, especially in nature areas and the eastern half of the country. That presents a potential conflict with agricultural areas and housing, which keep the ground water level artificially low. By de-fragmenting land usage in the Netherlands and combining fewer functions within a water system, we can alleviate the conflicts in land use and create margins between conflicting interests. That will make it easier to adjust water levels to specific needs. This will require us to make some difficult choices, but not making such choices will present us with even larger problems in the longer term.

3. Embedding in the law

In 2022, the government chose the ‘Water and Soil Preeminent’ policy line as the guiding principle for land use in the Netherlands. At the moment, we can see that there are still policy processes and political decisions that are in conflict with this policy. That includes building housing in the floodplains near Arnhem, which is permitted by law even though it is in conflict with the policy guideline. To prevent situations like that in the future, ‘Water and Soil Preeminent’ must be implemented in the law to ensure that it is not limited to good intentions alone. A scientific advisory council can help design and amend regulations to take new extremes and the latest scientific developments into consideration.

4. Future-proof construction

One aspect of the ‘Water and Soil Preeminent’ policy is future-proof construction. That not only entails building houses on piles or other local technical solutions, but also preventing homes from being built in certain locations. Local water levels are often kept low for agriculture and housing.

As a result, the land subsides, causing the water level to be lowered even further, which causes more subsidence that endangers foundations and may result in salt-water seeping to the surface. And so on. This is an irreversible process. It makes water authorities’ work more difficult, and insurance companies warn that the damages are becoming unaffordable. So it would be wise to implement a required climate test to ensure buildings are future-proof, so that everyone can keep their feet dry.

One thing is certain: sea levels are rising, extreme precipitation and river levels are increasing, and rivers are having more and more difficulty draining into the North Sea. So it is crucial that policies such as ‘Water and Soil Preeminent’ are embedded in the law in the very near future. That will help us deal with unpleasant surprises in the future. We are simply running out of time to adapt to these changes.

Maarten Kleinhans is Professor of Bio-geomorphology of Rivers and Estuaries at Utrecht University. With the help of his massive tidal facility the Metronome, he studies how the changing patterns of channels and banks are created by tidal flows in river estuaries.

Esther Stouthamer is Professor of Delta Evolution and Subsurface Processes at Utrecht University. Her expertise lies in the field of geological and geomorphological development of deltas, the resulting subsurface build-up and characteristics, and subsurface processes.

Niko Wanders is a researcher of hydrological extremes at Utrecht University. His field of expertise is the interaction between extreme drought or precipitation, climate change and human water consumption.