Freshwater shortages and more flooding: the new Delta scenarios show that we need to make major steps ahead this century

Published on: 25 April 2024, 10:28 hrs - Latest update: 14 May 2024, 08:58 hrs

24 april 2024, Deltares presented the new Delta scenarios for the Netherlands. 4 scenarios show what we need to take into consideration in policy for water and spatial planning until the end of this century.

In all 4 scenarios, the agendas relating to water will become a lot more challenging: freshwater shortages in summer will increase, there will be more problems with excess water caused by rainfall, and floods will have more impact. Bottlenecks relating to water shortages, problems with excess water and flood risk management are stacking up. This will affect all of the Netherlands.

About the Delta scenarios

The Delta scenarios are published every 6 years. They are based on the latest insights from, among others, the Royal Netherlands Meteorological Institute (KNMI), the Netherlands Environmental Assessment Agency (PBL), Wageningen University & Research and Deltares. They do not set out new policies.

The scenarios provide an overall picture of developments that affect water policy, such as climate change, activities to reduce greenhouse gas emissions, and socio-economic and spatial developments. With the knowledge from the Delta scenarios, policymakers and agencies like Rijkswaterstaat can get to work on effective approaches to keep the Netherlands safe and liveable.

Drier, but also wetter

The focus is on 4 scenarios between now and 2050 and 2100: Warm, Steam, Rapid and Space. All of them are possible and all of them must therefore be taken into consideration.

In all 4, the summers will get drier and winters wetter due to climate change, resulting in greater challenges. In Warm and Steam, climate change is strongest. In Rapid and Space, there is a strong global effort to reduce greenhouse gases. In Rapid and Steam, the population grows; in Space and Warm, there is more space for nature. These developments also place some demands on water policy.

Increasing water shortages

One of the most pressing agendas involves keeping fresh water available for all kinds of societal functions such as agriculture, shipping, nature, drinking water, energy and industry. The amount of fresh water available during the summer period is reflected in all the Delta scenarios, because there will be long dry periods and more water will evaporate due to higher temperatures.

There will also be shortages because less water will flow through our rivers in the summer, and salt water will intrude further and further inland. These developments will be exacerbated as the climate continues to change.

On the other hand, demand for water will rise significantly in all scenarios, for example to flush water systems (to manage salinity), the irrigation of agricultural land, the expansion of nature reserves and higher demand for drinking water. 

A new factor requiring large amounts of water will be the raise of groundwater level in low-lying peatland to combat subsidence and reduce carbon emissions. The equilibrium will be disturbed and water shortages will become more frequent. Not all functions can be supplied with enough water at all times, with damage to society as a result.

Increasing problems with excess water

The probability of problems with excess water is also higher in all scenarios; in the summer because of peak rainfall and in the winter due to long periods of rain. Moreover, extreme conditions will coincide more often: intense rainfall and high river discharges and higher sea levels, so that not enough water can be discharged.

The damage can be considerable in both urban and rural areas. Flooding can be disruptive when roads are impassable, hospitals are no longer accessible, or when electricity or communication networks fail.

Floods with greater consequences

In all scenarios, we need to take action to maintain our protection against flooding at the same safety standard. The sea level will rise and river discharges will increase in winter. In addition, with more people living behind the dikes and more economic assets being located behind the dikes, floods will have more impact.

The Flood Protection Programme is making the associated preparations for 2050. If global emissions are not reduced, the challenges relating to flood risk management will continue to increase after 2050.

Consequences for all

The Delta scenarios show that water policy is facing major challenges. In all 4 Delta scenarios, the water agendas become more extensive. Bottlenecks relating to water shortages, problems with excess water and flood risk management are piling up.

Everyone in the Netherlands will feel the pinch. The bottlenecks are becoming increasingly structural in nature. That affects our entire country and it will have consequences for all water users, including drinking water supplies, keeping water in ditches fresh, and managing groundwater salinisation in the low-lying Netherlands.

Using the Delta scenarios

The Delta scenarios are starting points for water policy, for the Delta Programme and the agencies concerned. But they can also be used in other areas such as in spatial policy (the National Spatial Policy Document) or the National Programme for Rural Areas.

The scenarios help in policy development. They show where bottlenecks will arise in the medium and long terms, and where solutions are needed. In this way, we can prepare in good time and work adaptively on a safe and liveable Netherlands.