Vulnerabilities - the Netherlands

The adaptive capacity of the fresh water supply is limited in its current setting; further warming and an increasing precipitation deficit can cause considerable problems as early as 2050. More frequent heat waves will cause more frequent peaks in the demand for water. Some surface water abstractions will experience more frequent periods when the water is too saline for treatment and the intake has to be temporarily shut down (1).

Preparing drinking water from poorer quality or even brackish water is technically possible, but very expensive. On the other hand it is expected that the fresh water bodies under the dunes and under inland hills (like the Veluwe, Utrechtse, Drentse en Overijsselse Heuvelruggen) will expand due to higher precipitation levels. These water bodies are also used for preparing drinking water (1).

The main causes of (expected future) constraints in freshwater supplies are (13,14):

• a shortfall on water available from rivers and canals;
• excess demand on reserves, or reserves exhausted (IJsselmeer);
• accelerated salinization of intake points (below the major rivers: Gouda and Bernisse);
• groundwater levels on the higher sandy grounds are sinking and water supply from the main water system is hardly possible;
• salination of parts of the southwest estuary area and water supply from the main water system is hardly possible.

To date, the frequency of these constraints has been acceptable in policy terms. Hence, there is no policy in place for structural water shortages, only for incidental dry periods – for which there is the water distribution priority sequence. This policy aims for adequate water supplies – also in extremely dry years – for safety, utilities and to prevent irreversible damage.

The extremely dry and hot summer of 2003

The summer of 2003 was extremely dry in large parts of Europe. In the Netherlands the drought was somewhat less extreme: such a dry year occurs on average once every 10–20 years. Due to the low supply of water in the Rhine, the brackishness from the sea gradually spread inland, with the result that in the middle of August the inlet points of the Rhineland and Schieland Water Boards became brackish (2).

The discharge requirement that cooling water may be no warmer than 30⁰C meant that several companies could only satisfy this criterion by reducing their production capacity. Three hydroelectric power stations had to run on a very limited capacity for several weeks (10–25% of normal). The combined result was a threatened shortage of electricity in the Netherlands (2).

A number of dykes also collapsed as a result of the drought (Wilnis, Rotterdam, Stadskanaal). There are about 3500 km of peat dykes in the lower regions of the Netherlands (2).

Dry summers, like that of 2003, will occur more frequently, leading to damage to agriculture and shipping (1).

Groundwater reserves

The fresh groundwater reserves in The Netherlands will hardly change in the 21st century. Even under a relatively strong climate change scenario (the Dutch W+-scenario) and 85 cm sea level rise, the groundwater reserves will still increase by about 1% (3).

In an average year 8-9%, and in a dry year 12-15% of the groundwater withdrawal is used for irrigation. This withdrawal generally takes place within just a couple of days. This century the need for irrigation may increase due to climate change by 5% (low (G) scenario) to 70% (high (W+) scenario) (3).

In several parts of The Netherlands agriculture and nature depend on isolated fresh water bodies in a area dominated by brackish and salt water seepage. These water bodies are threatened by a reduction of the precipitation surplus in the summer which may increase damage by salt (3).

Water demand

The expectation is that the average demand for drinking water will rise by several percentage points due to the rise in temperature. More peaks in the demand for drinking water are expected in the future as a result of climate change  (2).

Salt intrusion through sea level rise

The impact of sea level rise on salt intrusion through groundwater will probably be limited. It has been estimated that 3 meter sea leve rise will increase salt water intrusion via groundwater flow up to around 10 to 20 km land inward from the coastline and lower river reaches (20).

Low river flow Rhine

Average summer discharge of the River Rhine at the Dutch-German border (Lobith), spanning the summer months April – September, has not changed significantly over the period 1950-2018 even though there is a significant trend of less summer precipitation over the Rhine catchment in this period. The variability in discharge at Lobith is large and possibly other factors compensate the trend in precipitation (19).

Recently, a thorough study has been carried out into the change of the discharge of the River Rhine during the 21st century. It was concluded that average discharge during summer and winter half-year will increase in 2021-2050 with respect to 1961-1990. At the end of the century (2071-2100) average half-year discharge is projected to increase in the winter and decrease in the summer (4).

In summer half-year precipitation is projected to decrease in 2071-2100 whereas no significant change is calculated for 2021-2050. Therefore, low summer discharge is projected to decrease in 2071-2100 with respect to 1961-1990 (no trend for 2021-2050) (4). A reduction of low flow volumes up to −50 % was shown for the Rhine near Lobith (Dutch-German border) in the period 2070-2099 compared with the reference period 1981-2010, in an assessment based on five climate (GCMs) and five hydrological models, and four different scenarios of climate change ranging from a low- to a high-end scenario of global warming (the so-called RCPs 2.6, 4.5, 6.0 and 8.5) (18).

In the future shipping will be hindered by low flow in the summer more often. Fresh water input into reservoirs such as lake IJsselmeer during long summer periods of low flow will strongly decrease. During these periods the vegetation in the river area will suffer from drought stress due to the low groundwater tables. Also, combating salt intrusion (mainly near Rotterdam) will be complicated when river discharge is (too) low.

In the previous century water temperature of the Rhine has risen in all seasons. In the future temperature rise will continue. This will limit cooling capacity of electricity plants, especially in dry summers.

In the Netherlands a so-called Delta committee wrote a report on possible (worst case) climate change, sea level rise and river discharge changes in 21st century. Based on this report an adaptation strategy is being implemented to climate proof the country. The Delta Committee projected a reduction of average summer Rhine discharge from 1700 m3/s at present to 700 m3/s in 2100 (5).

Low river flow Meuse

Similar to the expectation for the Rhine, the winter discharge of the Meuse will also be higher in the future than it is at present. For the dry climate scenario in particular, the summer discharge will be even lower than is currently the case. In the present situation a low water level on the Meuse is already a problem, and only a slight change is enough to make the situation in the summer worse (2).

Fresh water supply in Lake IJsselmeer

Lake IJsselmeer (and the connected Lake Markermeer) is one of the largest fresh water lakes in the Netherlands and serves as a fresh water supply for the northern provinces. The water is used for agriculture, to maintain a sufficiently high water level in the inland waters, and to flush the salt from the ditches and the canals in the area. In 2050 the present volume of water in the lakes is probably insufficient to serve all the interests in a dry summer, especially when farmers invest in more sprinkling facilities. Strategies are being assessed how to increase fresh water supply in the Netherlands in the course of the 21st century. Possible measures include adaptations to these lakes (6).

Vulnerabilities Southwest Delta

Rapid climate development across large parts of the Southwest Delta would increase demand for freshwater due to salinization, with increased salt water seepage in the regional water system. This type of scenario would require a larger external input of freshwater to flush the regional water system. More freshwater would also be needed for drinking water and industry. In or around 2050 freshwater requirements in the delta could rise by a total of 40% on 2011. Whether or not this additional requirement for freshwater forms a constraint as from 2050, will depend on input from the main water system and regional basins (West-Brabant and Zeeuws-Vlaanderen) (13).

Specific to this area are the so-called freshwater lenses and their important function in supplying freshwater for agriculture. Area-based studies are underway into whether and where a tipping point is reached, i.e. if and when the freshwater lenses will disappear due to desiccation and freshwater discharge via drainage (13).

Overall strategic freshwater reserves for the entire southwest of the country are formed by the Biesbosch, Hollands Diep and Haringvliet. Reduced river discharge would put pressure on these reserves (13).

Europe: five lake categories

There are almost one and a half million lakes in Europe, if small water bodies with an area down to 0.001 km2 are included. The total area of lakes is over 200,000 km2; in addition the manmade reservoirs cover almost 100,000 km2. The response of European lakes to climate change can be discussed by dividing the lakes into five categories (7):

Deep, temperate lakes

Typical representatives of this class are e.g. Lakes Maggiore, Ohrid, Geneva and Constance with mean depths of 177, 164, 153 and 90 meters, respectively. Due to the great depth and relatively mild winters, there is usually no ice cover. The future climate change in Europe may suppress the turnover in deep lakes. This implies the enhancement of anoxic bottom conditions and an increased risk of eutrophication. The oxygen conditions can also be anticipated to deteriorate due to increased bacterial activity in deep waters and surficial bottom sediment.

Shallow, temperate lakes

Balaton (600 km2, 3 m) in Hungary and Müritz (114 km2, 8 m) in Germany belong to this class. Increasing water temperatures may result in intensified primary production and bacterial composition. The probability of harmful extreme events, e.g. mass production of blue-green algae, will increase. The impacts may extend to fish life; changes in species composition and reduced fish catches will be anticipated. The use of the expression 'thermal pollution' is well justified for these lakes.

Boreal lakes

Ladoga (17 670 km2, 51 m), Onega (9670 km2, 30 m) and Vänern (5670 km2, 27 m) are the largest in this class, being also the three largest lakes in Europe. This group includes about 120 lakes with an area exceeding 100 km2. Most lakes of the boreal zone mix from top to bottom during two mixing periods each year. Shortening of the ice cover period will be the most obvious consequence of climate change in these lakes. This could improve the oxygen conditions in winter and spring.

Arctic lakes

These are mainly small water bodies in northern Scandinavian mountains and in the tundra region. Arctic lakes are generally considered to be particularly sensitive to environmental changes. Melting permafrost may seriously threaten the ecosystems of arctic lakes. In some cases the whole lake may disappear as a consequence of ground thaw and enhanced evaporation.

Mountain lakes

To this class belong all high altitude lakes in central Europe and also those located in southern Scandinavia. Even if mountain lakes were connected by channels, physical and ecological constraints limit species migration between them. In a warming climate, there is no escape route; the only possibility for survival is adaptation.

Adaptation strategies

EU policy orientations for future action

According to the EU, policy orientations for the way forward are (9):

• Putting the right price tag on water;
• Allocating water and water-related funding more efficiently: Improving land-use planning, and Financing water efficiency;
• Improving drought risk management: Developing drought risk management plans, Developing an observatory and an early warning system on droughts, and Further optimising the use of the EU Solidarity Fund and European Mechanism for Civil Protection;
• Considering additional water supply infrastructures;
• Fostering water efficient technologies and practices;
• Fostering the emergence of a water-saving culture in Europe;
• Improve knowledge and data collection: A water scarcity and drought information system throughout Europe, and Research and technological development opportunities.

Managed aquifer recharge

Comprehensive management approaches to water resources that integrate ground water and surface water may greatly reduce human vulnerability to climate extremes and change, and promote global water and food security. Conjunctive uses of ground water and surface water that use surface water for irrigation and water supply during wet periods, and ground water during drought (15), are likely to prove essential. Managed aquifer recharge wherein excess surface water, desalinated water and treated waste water are stored in depleted aquifers could also sup­plement groundwater storage for use during droughts (16,17). Indeed, the use of aquifers as natural storage reservoirs avoids many of the problems of evaporative losses and ecosystem impacts asso­ciated with large, constructed surface-water reservoirs.

Stratetic options for climate-proofing the Netherlands

Climate-proofing freshwater supplies in the Netherlands will require a more flexible water system and better use of the water in the Rhine (10).

At the moment, there appears to be little need for substantial changes to the water level regime of the IJsselmeer. By 2050, assuming the present water-level regime, as well as a continuation of current land uses and the high (W+) climate change scenario, in an extremely dry year (occurring once every 100 years) about 70% of the water demand could be met. With a limited additional water-level fluctuation of 30 cm, in a similar year, 85% of water demand could be met (11).

In addition to the option of increasing the water reserves in the IJsselmeer, changing the management of the New Waterway is an interesting alternative. 80% of all the water in the Rhine is discharged through the New Waterway into the sea – even in dry years – to counteract salt water intrusion. Doing this more effectively, in other words with less water, will release more fresh Rhine water for other uses, such as the irrigation of agricultural land (10).

If the salinisation of the New Waterway can be counterbalanced by just part of this flow of fresh water, the problem of salt water intrusion in the lower stretches of the Rhine could be solved and more fresh water would become available for use in the west and south-west of the Netherlands. Possible variants of such a regime to reduce salinisation are step-wise reductions in the depth of the New Waterway (which is now more than 20 metres deep, up to Rotterdam), constructing groynes (permanent or temporary), temporary partial closure in extreme dry years, or installing underwater barriers or pneumatic barriers (10). However, little is known about the actual effects of these measures on the intrusion of the saline wedge (12).

Moreover, there are various possibilities for making regional water systems more flexible, thus, temporarily curbing demand for water in dry years. The main options are those of optimising water management practices and water management authorities taking a more flexible approach to salinity standards. A temporary increase in salinity in parts of the regional water systems will not necessarily have significant adverse effects on agriculture. For valuable salt-sensitive crops, such as greenhouse horticultural crops, increasing use is already being made of separate water supplies to ensure the required water quality, thereby decoupling water supply from the regional water system (10).

Water pricing policy

Dutch provinces charge for groundwater abstractions in order to cover the costs for groundwater management. On a national basis, there is an environmental levy for groundwater abstractions (8).

Adaptation strategies - Delta Programme

In the Netherlands a Delta Programme has been initiated aimed at improving flood protection and securing fresh water supplies, and thus climate proofing the Netherlands in the 21st century. The Delta Programme focuses on three main topics: flood safety, fresh water security, and new urban development and restructuring (13).

The Delta Programme discriminates between 6 regions, each having their own vulnerabilities with respect to climate change, and thus asking for tailor-made adaptation measures:

1. Rhine estuary – Drechtsteden: flood protection of the Rhine – Meuse - Delta
2. Southwestern Delta: climate change impacts on flood safety, fresh water availability, nature and regional economic development from 2050 onwards
3. IJsselmeer Region: long-term water level management for flood safety (free discharge of lake water on the Wadden Sea under sea level rise) and fresh water security (a larger reservoir for dry summers)
4. Rivers: implementation measures for increasing discharge capacity Rhine and Meuse (short-term); securing flood safety along with addressing fresh water supply, shipping, nature and regional development (long-term)
5. The Coast: focus on a sustainable flood protection strategy and options for coastal expansion
6. Wadden Region: focus on several issues, a.o. integrated coastal and island management, innovation in dike construction, sediment budgets, and climate proofing areas outside the dikes

Delta Decisions in 2015

In 2015 the Delta Programme will result in five Delta Decisions for flood safety and securing fresh water reserves for 2050 with an outlook towards 2100. Proposals for the following Delta Decisions are foreseen (13):

1. Delta Decision Flood risk management.
2. Delta Decision Freshwater strategy. Strategy for sustainable and economically effective freshwater supplies in the Netherlands. This strategy provides insights into supply of and demand for freshwater and water security; makes statements on potential for water savings, optimal water distribution and future service levels in relation to functions and their impact on these functions; and clarifies the division of responsibilities between government, market and user.
3. Delta Decision Spatial adaptation. National policy framework new urban developments and restructuring and recommendations around flooding and heat stress.
4. Delta Decision Rhine-Meuse delta. Strategy for flood protection in this crucial transitional delta area, together with solutions for freshwater supplies. The Rhine-Meuse delta is the location of the major rivers, Rhine Estuary-Drechtsteden and the southwest delta. This is a key transitional area in the Dutch delta. River and sea come together here, and there is a wide range of interests requiring protection – both in terms of population and economic activity. The proposal for the Delta Decision comprises one or more strategies to ensure flood protection and sustainable freshwater supplies up to 2050 followed by a forward view to 2100.
5. Delta Decision Water level management Ijsselmeer Region. Strategy for water reserves in this lake in view of freshwater supplies and flood risk management. The proposal for the Delta Decision IJsselmeer area comprises a strategy for water level management in the IJsselmeer area for the period 2015-2050 with a forward view to 2100.

More information on these Delta Decisions and the steps to be made in the period 2012 -2015 is presented in the Coastal Floods theme.

Short-term measures

The sub-programme Freshwater will focus on measures and provisions that make the water system more flexible to find solutions on the short term. Potential measures will be assessed for feasibility and short-term impact (13):

• flexible water level management in storage of water during the winter six months – both for surface water and groundwater – for use in the summer six months;
• creation of water supply for important, currently vulnerable, water supply routes such as the Hollandsche IJssel which is subject to rapid salinization;
• deployment of temporary pumping units (emergency pumps) to move water from A to B;
• small-scale water storage, level-linked drainage and other small-scale, operational measures to optimize water use.

Long-term measures

Alongside increasing water reserves, seeking strategies and related measures will deliberately examine demand for water from the user-side. Also included will be agreements on quantity and quality with neighbouring countries. One possible solution being studied for feasibility is a structural increase of the level of the IJsselmeer. Regional self-supply is also being examined as a possible solution-path (13).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for the Netherlands.

1. Ministry of Housing, Spatial Planning and the Environment (2009)
2. Bresser (2006)
3. TNO Bouw en Ondergrond (2008)
4. Görgen et al. (2010)
5. Delta Committee (2008)
6. Ministry of Transport, Public Works and Water Management, Ministry of Agriculture, Nature and Food Quality, andMinistry of Housing, Spatial Planning and the Environment (2010)
7. Kuusisto (2004)
8. European Commission (DG Environment) (2007)
9. Commission of the European Communities (2007)
10. PBL Netherlands Environmental Assessment Agency (2011)
11. Meijer et al. (2010), in: PBL Netherlands Environmental Assessment Agency (2011)
12. Van Beek et al. (2008), in: PBL Netherlands Environmental Assessment Agency (2011)
13. Ministry of Infrastructure and the Environment, and Ministry of Economic Affairs, Agriculture and Innovation (2011)
14. Ministry of Infrastructure and the Environment, and Ministry of Economic Affairs, Agriculture and Innovation (2012)
15. Faunt (2009), in: Taylor et al. (2012)
16. Scanlon et al. (2012), in: Taylor et al. (2012)
17. Sukhija (2008), in: Taylor et al. (2012)
18. Pechlivanidis et al. (2017)
19. Philip et al. (2020)
20. Bonte et al. (2024)