Abstract

In the Netherlands, drinking water is sourced from river water and groundwater. Due to warmer and drier summers, there will be less water available for the drinking water supply in the future. At the same time, more drinking water will be needed because the population is growing. Moreover, the temperature of the drinking water in the water pipes will increase, which might lead to faster growth of pathogenic bacteria. RIVM has created a forecast for drinking water for the years 2050 and 2100, and devised potential solutions to ensure a sufficient supply.

RIVM concludes that drinking water demand could increase strongly in case of high population growth. In that case, additional drinking water sources are needed, which would increase pressure on both groundwater and surface water. As a result, drinking water production may become more expensive and more often associated with negative impacts on surrounding nature areas. Moreover, due to climate change, the availability of water sources could decrease at the same time. It is therefore important to prevent further climate change and to adapt the Netherlands where necessary to the effects that are already present.

RIVM has elaborated a number of different future scenarios for population growth, climate change and policy measures. In a light scenario with low population growth and little climate change, it appears that demand can still be met, but with little reserve capacity. This means that in unforeseen circumstances, there may be insufficient drinking water available. In the heavier scenario, the capacity is not sufficient to meet demand, let alone provide adequate reserve capacity. If the supply of drinking water becomes uncertain, this can have major consequences for the development of new housing and business activity. This entails significant social costs.

The RIVM has also studied the effect of policy measures. By using less water, less groundwater and river water are needed for drinking water production. For example, by showering less frequently and for shorter periods, and by using the small flush button on the toilet. In addition to these types of behavioural changes, the demand for drinking water can be further reduced with technical devices, such as toilets that use rainwater for flushing. However, such technical solutions are more expensive than behavioural changes.

In most of the Netherlands, drinking water is sourced from groundwater. During dry spells, the demand for groundwater increases - but this requires choices to be made. After all, lower groundwater levels can be harmful to nature and agriculture. Solutions include 'retaining' more groundwater in the soil.
In the west of the Netherlands, drinking water is mainly sourced from river water. In times of great drought, pollutants in rivers are diluted less. River water that is too greatly polluted may temporarily not be used as a source of drinking water. Until the river water is safe again, there will be an increased demand for water captured in dunes and basins. This is expensive and may harm nature in the dunes. The burden on dunes and basins can be reduced by keeping rivers in the Netherlands cleaner.