When someone talks about 1953, nearly everyone in the Netherlands immediately thinks of one specific major incident that happened that year: the North Sea flood. Since then, many interventions have taken place to prevent such a disaster from happening again. But, is the sea our main and real enemy in the fight against the water, or not?
First of all, what would happen if we did not have any protection against the water
at all? Approximately 60% of the Netherlands is flood-prone. In this area, roughly 70% of the Dutch population is living and 70% of the Dutch GDP is earned, meaning that a flood in this area would have massive economic and humanitarian consequences.
After the flood in 1953, the Delta-commission was created to come up with measures that had to be taken to protect our low-lying country from the sea in the future. The Delta plan was what they invented. According to this plan, multiple dams and storm surge barriers should have been constructed and many sea-dykes should have been raised to increase the safety standards, based on the economic value of the land that it protects. By the closing of some of the Dutch estuaries, the Dutch coastline was limited significantly, which made it easier to strengthen the sea-dykes.
Besides by sea-dykes, dams and storm-surge barriers, the Netherlands is also protected by dunes. The problem with dunes is that they ‘move’ under the influence of erosion. Therefore, the sand that is washed away needs to be replenished by the people, otherwise, the dunes may become too small and because of that start losing some of its strength. One of the solutions for this problem is the creation of the so-called ‘sand engine’. This artificial shoal also loses its sand due to erosion, but this sand is then deposited at another part of the coastline, a bit downstream. Thanks to these kind of inventions, the dunes stay where they are and so they keep the hinterland safe for the threat of the sea. The main guideline in constructing water protection structures is ‘soft measures (sand, dunes) when
possible, hard measures (dams, sea-dykes) when necessary.
However, the threat of flooding is not only coming from the sea, but the rivers in the Netherlands can also be dangerous for the land located behind the dykes. Because of climate change, the extremes in water discharge volume are becoming more extreme. This means that at peak moments, more water needs to be discharged than before. Therefore, measures need to be taken to ensure that in the future all the water still can be discharged and will not rise to extreme heights in the rivers. As a reaction to this prospect, multiple actions took – and are taking – place. A well-known example is the ‘room for the river-project’. This implies that by re-building dykes further from the river, there will be more space for the water to flow when it is needed. Also, highwater gullies were built at some places with the same purpose. These measures have as a result that the people that were living in the areas that now will be inside the dykes need to move or prepare themselves and their possessions to deal with floodings some periods of the year. Furthermore, in 2008, the ‘multi-layered safety approach’ (see featured picture) was launched. As the name says, it consists of three layers. The first one is protection, which is mainly the primary dyke system. Secondly, there is ‘risk-informed sustainable spatial planning’. This means that the effects of flooding should be limited by stopping with building in current flood-prone areas and stopping with creating new risk-zones. The third and last layer is crisis management and emergency response. This involves the coordination between the various emergency services, the authorities and the people in the affected area. Also, water-robust measures like emergency shelters and infrastructure that can withstand a lot of water are constructed.
All in all, the Netherlands is currently well-prepared for the expected sea-level rise and the increase of average and extreme water discharge in the rivers. However, as we move on and climate change may happen faster or will be more extreme than nowadays is expected, future changes to our water protection structures might be necessary.
This Girugten article was first published in GEO PROMOTION MAGAZINE, 23rd of February, 2019.