What does drought do to our groundwater

This means that the national water allocation hierarchy (verdringingsreeks) is being applied and not all functions that use water from the main water system can be fully supplied. In areas where water cannot be conveyed, such as the sandy regions in the east, centre and south of the Netherlands, insufficient rainfall and low groundwater levels are causing damage to nature, streams running dry and, where irrigation is not possible or permitted, damage to agriculture as well.

The current situation

The current situation is comparable to the dry summers of 1976 and 2018, and, if there is no prolonged rainfall in the coming weeks, the situation this year may become even more severe. Now that it has been raining in August and the grass is turning green, the initial emergency may appear to have passed, but replenishing groundwater takes more time. In some areas, it can take a year or more for groundwater levels to return to normal. As a result of climate change, summers like this are becoming ‘the new normal’, and in addition to emergency measures such as the water allocation hierarchy, we will also need to consider structural measures to maintain our water supplies throughout the year. Groundwater plays an important role in this.

Source: Groundwater | Drought Monitor | Rijkswaterstaat (dated 27 August 2026)

Groundwater and drought

Drought can lead to extremely low groundwater levels. Due to intensive drainage and groundwater use for irrigation, industry, and drinking water production, groundwater levels have compared with the natural situation already been lowered. In many locations, drought leads to an increase in groundwater abstractions, resulting in an even greater decline in groundwater levels. Consequently, less groundwater remains available for nature, for example. This is particularly evident in sandy areas, where groundwater-dependent nature already suffers from lowered groundwater levels even without drought. Elsewhere, low groundwater levels can cause drought damage to non-irrigated agriculture and damage to buildings and infrastructure due to peat oxidation, shrinkage of soft soils or the drying out of foundations (timber pile decay).

Groundwater as an important water supply

The Dutch subsurface is largely highly permeable and therefore contains relatively large groundwater reserves that are used throughout the year. Not all of this groundwater is fresh water. In coastal areas, shallow groundwater is often already brackish or saline, and in the rest of the Netherlands groundwater at greater depths can be brackish or saline also. At present, groundwater is an important source of our drinking water (60%), and many farmers and businesses in the east, center and south of the country also extract groundwater. When water availability from rainfall and major rivers becomes scarce during summer periods, there is a strong likelihood that groundwater will increasingly be viewed as a water source. However, if this source is temporarily insufficiently replenished, or not replenished at all, by rainfall or surface water, it is important to use groundwater carefully. Should a water allocation hierarchy for groundwater perhaps also be introduced during periods of extreme drought?

Maintaining a balance between groundwater functions

Although fresh groundwater can extend to depths of 200 to 300 metres, only a small proportion of this total can be used through abstraction. Because extracting groundwater lowers the groundwater table, while many functions such as agriculture, nature, built-up areas, infrastructure, and peatlands depend on that groundwater level. For some functions, groundwater levels must not be too high because of flooding risks, but levels that are too low are more often a problem. As mentioned earlier, this leads to the drying out of nature, peat oxidation and therefore CO₂ emissions and land subsidence, damage to house foundations and infrastructure, and resulting settlement and subsidence issues.

Source: Perspective on Groundwater (Deltares, 2025)

Using groundwater reserves wisely

A large proportion of the deeper groundwater has relatively high quality because of its age and the filtering effect of the soil. We should not waste this ‘valuable groundwater’ but instead reserve or use it only for high-value applications such as drinking water. It is important to prevent groundwater quality from deteriorating because of pollution from agriculture, urban areas and industry. Especially as we move towards a future with more periods of (extreme) drought, we must use our groundwater reserves wisely.

Groundwater now and for future generations

With sufficient in-depth knowledge and understanding of Dutch groundwater systems and new technologies, there may be opportunities to use new groundwater sources, such as brackish groundwater in coastal provinces or groundwater reserves beneath the IJsselmeer. Measures can also be taken to enhance the replenishment of groundwater reserves, for example through subsurface infiltration or changes in land use (crops with lower evaporation rates, less paving and hard surfacing). Naturally, the water that is infiltrated must not contain pollutants. In this way, groundwater will also remain available for future generations.

Another solution is sponge action

By retaining water in the subsurface for longer during wet periods, it is possible to raise groundwater levels before dry periods begin. The landscape then stores water like a sponge. An important ‘sponge measure’ is reducing drainage by closing or removing drainage systems, raising ditch water levels, filling in ditches and/or raising ditch beds. This slows down groundwater discharge. For a structural effect, interventions in only the smaller ditches are insufficient. Sponge measures must also be implemented in larger watercourses and across wider areas, such as 500-metre buffer zones around nature reserves to prevent desiccation. Introducing restrictions on groundwater abstraction near nature areas is also important. During drought, bans on surface water abstraction are regularly imposed, but in the case of groundwater this still happens only to a limited extent.

Rijkswaterstaat Drought Portal

Groundwater and surface water as one system

Groundwater and surface water abstraction are still managed separately in most areas. A new approach is needed to integrate the use and management of groundwater and surface water more effectively. Smart and flexible combinations in space and time, where groundwater and surface water sources are used together, can deliver significant benefits. Areas that are vulnerable to low groundwater levels during drought should ideally be protected, particularly during the summer months. During wetter periods, more water can be retained or infiltrated for use during droughts. Information systems with current and accurate groundwater data and forecasts are indispensable for developments of this kind.

Limits to groundwater?

Measures to reduce the impact of drought through groundwater management are therefore possible. The key is to implement them well in advance (during winter or early spring) or on a permanent basis. Once drought has set in, it is effectively too late, particularly where groundwater measures are concerned. However, there are limits to the extent to which groundwater can compensate for the effects of drought. If future droughts become more intense and prolonged, it is uncertain whether the measures we currently know and apply will be sufficient to reduce the associated risks. We will also need to adapt our water use and land use to a drier future.