Delta scenarios provide guidance for water management

The 4 scenarios show the conditions we need to consider in water and spatial planning policy up to the end of this century. Delta Commissioner Co Verdaas explains what this means for the water challenges for 2050 and 2100.

What do you think are the notable findings?

‘For me it is very clear that our centuries-old strategy of containment and control no longer works. Instead of draining water to the sea as quickly as possible, we actually need to retain water more.’

‘In all 4 scenarios you see extreme weather increasing due to climate change. That means both extremely wet and extremely dry weather. And it’s not just safety - drought and salinisation are also the big challenges for the future. The years 2050 and 2100 show a range which is also dependent on modifiable conditions, such as global carbon emissions.’

How do the Delta scenarios help with the development of water policy?

‘The scenarios are pictures of the future of developments that affect water policy. What if things don't go well? What if things do go well? And everything in between. The underlying models used have shown themselves to be realistic over the past 20 years. So it is evidence-based.

‘The scenarios provide guidance when reassessing our Delta decisions. It is also vital information when drawing up spatial planning policies that have an impact into the distant future.’

‘Within the Delta Programme, we use the Delta scenarios to have measures for a climate-robust future developed and assessed, and draw up plans for the future on the basis of this. We describe this, and politicians make the choices. The scenarios therefore help develop policies.’

So what is the role of politicians?

‘The scenarios are politically-neutral, but you cannot dismiss their importance. They are of existential significance for the Netherlands. They show where things will get tight in the medium and long term and where solutions are needed.'

'In order to maintain safety up to 2050, climate action measures will have to be brought forward. That will require more money and resources, including for the post-2050 period. It is up to politicians to weigh the interests in this.’

Which items are already significant in the short term?

‘Fresh water availability is an urgent issue. We are hitting the limits of fresh water stocks during periods of drought. Drinking water companies are sounding the alarm and farmers’ yields are also suffering due to drought, salinisation and excessively wet soil. This makes the land difficult to cultivate. This raises several issues.’

‘How do you retain water even more? And how do you share out scarce water during droughts? We are now working on these kinds of questions.’

‘The Delta scenarios show that the today's extremes are the climate of the future. We cannot always fully deal with those extremes any more. We have already seen that in Limburg in 2021. Maintaining vital functions in extreme situations could then be the challenge. Such a choice is also a form of adaptation.’

What will be the big changes in water management?

‘The current emphasis on protecting with sand suppletion and dyke reinforcements remains. But as sea levels rise faster, we have to make choices. We are developing the knowledge for this within the Sea Level Rise Knowledge Programme.’

‘For instance, coastal defences can be enhanced on the seaward side, and we have identified a solution approach that involves flexing with the water more. We do not need to make choices now, but it is important that we have the knowledge about the solution approaches and their consequences.’

Which challenges are worrying?

‘What is important for water management is that we are seeing a rapid accumulation of water challenges. Areas in both the high and low parts of the Netherlands are suffering water shortages and flooding and water safety challenges. Where things are already tight, it is going to get tighter. And new challenges are emerging. This affects all areas and all users.’

‘So our water management will have to focus on this cocktail of water challenges. We will need to get a good idea of the balance between choices: what is good for countering flooding could increase the problem of water shortages and vice versa.’

Do nature and climate measures work well together?

‘Perhaps they do. The Sea Level Rise Knowledge Programme is currently developing a Nature Based solution approach. This involves measures that contribute to the conservation and restoration of the ecosystem and biodiversity. We are investigating whether these types of solutions are also sufficiently effective in terms of water safety and fresh water supplies.’

What role can EIAs play in this?

‘EIAs are not a tool in the Delta Programme. But EIAs do help identify impacts on nature and the environment. Climate used to be a soft aspect, but is now a prerequisite. If you don't invest in measures upfront, the bill will be higher later. And EIAs are also a kind of stress test, where all the impacts are set out neutrally. That helps with the choice.’