The drought of 2026 is not yet over, and some of its effects are already visible. There are economic consequences for agriculture, transport and industry. But there are also consequences that are less visible and may have long-term effects. These include the extinction of species in dried-up streams and ponds, land subsidence leading to damage to building foundations and increased CO₂ emissions, and damage to dykes. How well do we understand these consequences? And what does this mean for freshwater policy?
Our experts, together with other research institutes and partners, assessed the impact of the 2022 drought. That research showed us that we had learnt a great deal from the 2018 drought, and this ensured that we were better prepared in 2022. Fortunately, in 2026 we were again ready with additional water from the IJsselmeer, the Climate-Resilient Water Supply (KWA) scheme and creative solutions such as the emergency water supply to the Brielse Meer. However, the study on 2022 also showed that many consequences of drought remain under-examined. Not everything can be mitigated by water supply from the major rivers and a different water distribution system. Consider, for example, the damage to agriculture and nature in Zeeland and on the Hoge Zandgronden. In the peatlands of the Lowlands, too, groundwater levels have dropped significantly despite the water supply. It will only become clear in a few months’ time how much extra CO₂ has been emitted and to what extent the land subsidence is irreversible.
An initial assessment of the social consequences
Although the drought season is not yet over, we can provide an initial assessment of the potential consequences of this drought. We do this by comparing the drought indicators for the three droughts of 2018, 2022 and 2026.
- The national average precipitation deficit peaked at 310 mm this year, which is comparable to the other dry years.
- Everywhere, groundwater levels were at least as low as, or lower than, those in 2018 and 2022.
- The Rhine discharge fell below 1,000 m³/s more than a month earlier this year and dropped to a historically low level of 565 m³/s. [see figure]
- Buffer usage of the IJsselmeer and Markermeer was higher than in other years, partly due to the timely raising of water levels.
For shipping, the duration of low discharge periods is significant. In 2018, the discharge remained below the critical threshold of 1,020 m³/s for 125 days, forcing businesses to draw on their stocks. In 2022, the critical low-water period lasted 60 days and the impact on shipping and industry was less severe. The current low-discharge situation has now lasted 68 days, but forecasts indicate that the discharge will remain well below 1,000 m³/s for the time being. In addition, this year’s extremely low discharge levels led to the closure of the Twente Canals, causing, according to the Dutch Association for Inland Ports, significant damage to industry in Twente.
The precipitation deficit comparable to that of 2022 and the extreme fall in groundwater levels already provide an initial indication of crop yield losses, damage to groundwater-dependent wildlife, and land subsidence. In 2018 and 2022, the impact on nature, land subsidence and damage to building foundations was likely to be particularly severe as a result. The effect of the dry summers on nature in the sandy areas (including the drying up of streams and fens) is exacerbated by structural desiccation in these areas resulting from intensive drainage and groundwater abstraction.
In 2026, bans on water abstraction from groundwater and surface water were imposed on a larger scale to prevent damage to dykes and the natural environment. For example, in the Delfland Water Board, greenhouse growers were not exempt from a ban on irrigation, and public green spaces were also affected.
As in 2022, drinking water companies did not experience any major problems. However, the situation was tense at the intake points along the River Lek and the IJsselmeer, where water managers had to make every effort to prevent salinisation.
Finally, a drought places heavy demands on the crisis management teams at Rijkswaterstaat and the water boards, as the drought persists for so long, many emergency measures are implemented, and recovery and clean-up work must be carried out in the aftermath. We also saw this in 2018 and 2022. The societal costs of crisis management during droughts have so far been overlooked.
Better monitoring of the consequences of drought is needed
This overview provides an initial indication of the potential consequences of the 2026 drought. The 2022 drought analysis had already shown that the potential consequences of drought can be significant and, in some cases, irreversible. Furthermore, many of these consequences cannot be mitigated by altering water allocation. Demand exceeds the amount available from the rivers, or the supply capacity is insufficient. More importantly, however, a large proportion of the consequences cannot be mitigated by additional water supply. This results in damage to groundwater-dependent ecosystems, agriculture and shipping, as well as damage to building foundations, increased CO₂ emissions, land subsidence and damage to dykes. To prevent this damage, a different approach to the water system and land use is required.
Broadly speaking, the direct economic consequences of drought are known, but the wider societal consequences and long-term effects are not yet fully understood and are difficult to quantify. This is, however, necessary for formulating measures and underpinning policy. Some data and information are already available on various platforms, but these are not yet centrally collated and analysed. There is a lack of a central database containing meteorological, hydrological and societal drought indicators to track the severity and frequency of droughts over the years (on a long-term, structured basis) and to interpret the changes therein. To this end, Deltares is collaborating with organisations including PBL and CAS on the National Climate Adaptation Monitoring programme.
In the coming months, Deltares will carry out a quick scan to further assess the consequences of the 2026 drought and to centrally collate the data.