Drought is one of the issues addressed by the Delta Plan on Spatial Adaptation, along with waterlogging, heat, and urban flooding. The KNMI'14 scenarios of the Royal Netherlands Meteorological Institute show that precipitation patterns are changing. Drought can jeopardise the quality and availability of water in our country. This page provides a brief explanation of the drought issue and links to other relevant pages within and beyond the Knowledge Portal.
How does drought originate?
The term “drought” usually refers to situations in which problems may arise as a result of a shortage of water. In the Netherlands, such shortages will occur in the event of a major shortage of precipitation and/or a substantial decrease in river discharges and the water levels of lakes that are used for our water supply. In the Netherlands, precipitation shortages occur every summer, but in some years such shortages will escalate sharply, and a drought situation will arise as has happened in, e.g., 1976 and 2018. In such cases, the use of water is curbed, and the distribution of the water available in rivers and lakes is optimised in order to compensate for the drought. Under extreme conditions, full compensation will not be possible. Water cannot be transported everywhere whilst the water supply is limited.
At the height of the 2018 drought, in August and September, the precipitation shortage amounted to some 300 mm. Such shortages can only be made up by large volumes of precipitation in the subsequent autumn and winter. Prolonged drought, such as in 2018, will occur once every 30 years in the Netherlands under the current climate conditions.
What is the impact of drought?
Prolonged drought can have a wide variety of consequences. Water shortages can cause damage to crops and nature. Furthermore, dry summer conditions will add to the risk of fires in nature. Drought can also result in (additional) soil subsidence. Low groundwater levels may cause peat and clay areas to subside, which will damage vulnerable infrastructure, buildings, and foundations.
The Climate Impact Atlas shows how drought can develop in the Netherlands as a result of climate change. The Spatial Adaptation standardised stress test information leaflet indicates how the Atlas can be used to map out an area’s vulnerabilities.
Will the future be drier?
Model calculations regarding drought in the future climate do not present a univocal picture. According to two of the four KNMI’14 scenarios, summers will be drier and river water supplies will decrease. The other two scenarios show a minor increase in summer precipitation. However, a recent study has shown that drier conditions will be more likely.
How are we vulnerable to drought?
Drought can cause problems if it leads to an insufficient supply of water of a sufficiently high quality for particular purposes. Certain locations are more prone to the impact of drought than others. Differences can be observed, for example, between the elevated parts of the Netherlands and the low-lying parts. The elevated parts consist of the elevated sandy soils in the east and south of the Netherlands; the low-lying parts comprise the western provinces. In many elevated regions, water cannot be supplied from rivers; their residents are fully dependent on precipitation and groundwater. This is why in elevated regions, continued drought will be more likely to prompt irrigation bans, whilst streams and drainage canals will be more likely to dry out. Low-lying regions, on the other hand, can be supplied with water from rivers and other freshwater sources, such as Lake IJsselmeer, but an insufficient supply of river water can cause salinisation. In spring, the water levels of several bodies of water will be raised, in order to secure a larger water supply for low-lying parts of the Netherlands during dry summer months.
How can we contain the impact of drought?
The Delta Plan on Freshwater Supply stipulates that governments and consumers will provide transparency regarding water availability and map out the risks. This information can be translated into measures and agreements on dealing with shortages. If a water shortage occurs, the National Coordination Committee for Water Distribution (LCW) will go into action and provide advice regarding the distribution of the water that is available in the major rivers across the sectors that depend on this water. Examples of such sectors are the agriculture and horticulture sectors, the shipping sector, and nature management. The LCW committee reviews the water requirements of each sector, but also considers the water quality appropriate to its use. The distribution of the available water has been set down in a prioritisation scheme. The video film below explains the prioritisation scheme.
A range of methods is available to contain the impact of drought, among which are the optimisation of the water distribution through climate-proof supply routes, smart flushing, and the utilisation of buffers. One option is using the soil as a buffer. During wet periods, water is retained in the soil, to be used to (help) bridge periods of precipitation shortage. An additional advantage of keeping groundwater levels up to standard is that it combats soil subsidence in areas featuring peat or clay soil. Systems such as underwater drainage or active urban groundwater management prevent groundwater levels from falling excessively and thus combat the adverse effects of drought, yet raise water requirements.
In addition to water retention in the soil, water can be stored in water reservoirs, for example, on the premises of glasshouse market gardeners or in nature reserves. Operational management also offers opportunities for savings or circulation. Reuse of water flows, such as effluent, may also help to limit shortages.
Individual residents can do their part to contain the impact of drought. For example, they can implement measures to prevent wastage of water. Residents can design their gardens to collect water during wet periods, for example, in a rain barrel. In dry periods, they can use this water to water their plants. The Green-blue Grids design tool lists measures for climate-proofing gardens and surroundings. On this news page, a horticulturist gives tips on protecting gardens against extreme drought.