Droughts The Netherlands
Vulnerabilities - The Netherlands
What are ‘water shortages’?
In the Netherlands, water shortages are defined as the difference between supply and demand of water of sufficiently good quality. Water shortages may result from a high precipitation deficit, low river discharge, lack of (infrastructural) possibilities to redistribute the water, and a deteriorating water quality (including salinization and higher water temperatures) (1).
The precipitation deficit is defined as the maximum cumulative difference between precipitation and evaporation between April 1 and October 1. The average precipitation deficit is 151 mm. Extreme precipitation deficits (as occurred in 1911, 1921, 1959 en 1976) are over 300 mm. Even though the summer of 2003 was extremely hot, the precipitation deficit was relatively modest (220 mm). No trend has been observed in the yearly maximum cumulative precipitation deficit over the last 100 years (1).
In dry years the Rhine river discharge is about half the discharge of an average year. Meuse river discharge is much less than Rhine river discharge.
Water shortages during the summer are a common phenomenon in the Netherlands and are generally not considered to be problematic. These shortages result in the loss of income potential for especially agriculture and inland shipping. There are examples in the past, however, of water shortages in extremely dry summers (1976, 2003) that caused considerable damage to especially agriculture and forests (wildfires). In 2003 also the availability of sufficient cooling water for electricity production became critical. Water shortages will increase in the future, mainly due to climate change (1).
1976 is the driest year since the beginning of observations; the recurrence interval of the precipitation deficit of 1976 is 90 years. The combination of the precipitation deficit and low river discharge of 1976 has a recurrence interval of 110 years. All in all the summer of 1976 may be considered a once a century event. The summer of 2003 occurs once every 10-20 years. These recurrence intervals refer to the growing season (April 1 – October 1) and may be different for other periods (1).
Present supply and demand
Water supply in an average year is about 3000 mm. In the extremely dry year of 1976 it was 40% less. About 60% of the fresh water supply in the Netherlands comes from the river Rhine, 30% is precipitation and 10% stems from other rivers. On a yearly basis,60 to 80% of the river supply is discharged into the sea, depending on the drought conditions of the year. Even though this water is not used for agriculture f.i., it has a function though: to avoid salt intrusion in the river outlets, and to maintain a sufficiently deep navigation channel in the rivers (1).
In an average year 20%, and in a dry year 30% of the available amount of fresh water is evaporated, mostly by agriculture (55% of the surface area in the Netherlands is used for agriculture). The other interests that use fresh water (industry, drinking water supply), use three times as much in a dry year with respect to an average year; even during a dry year this amounts to less than 10% of the total water demand. 55% of the drinking water supply stems from groundwater, 45% from surface water. The annual fresh water production in the Netherlands is 1250 million m3, of which a small part is used by the industry (2).
In an average year the total shortage of water supply for all the interests at stake is 5 million m3, which is 0.16 mm of water covering the entire country. In an extremely dry year the shortage of supply is 90 million m3 , which is 2.7 mm of water covering the entire country. The shortage of ground water in the root zone of the plants is much larger and may be up to 5.5 billion m3 in an extremely dry year. This amount agrees with a 4.5 metre water depth of the lake IJsselmeer, which is one of the largest fresh water lakes of Europe (1).
Future supply and demand
Different climate change scenarios show different impacts on future water shortages. Two extreme scenario’s have been analyzed with respect to future droughts in the Netherlands. A scenario with modest climate change indicates that water shortages in 2050 may be quite similar to the present situation. A scenario in which the climate changes fast shows a 16% increase of evaporation and a 20% reduction of precipitation in the summer; this change may be twice as large in 2100 (2). An increase of water shortage in dry summers seems likely in the next 50 years. Low river discharge in dry summers will probably also reduce; for the Rhine a significant reduction is expected only after 2050, however (10).
The impact of climate and land use changes on Rhine high and low river discharge was studied (16). Two scenarios were used: a moderate (G+) and warm (W+) scenario of 1 and 2°C temperature rise in 2050, respectively, compared with 1990, and in both scenarios milder and wetter winters, and warmer and drier summers due to changes in air circulation patterns in Western Europe.
From this study it was projected that the discharge of the Rhine at Lobith will decrease on average by 5% (G+) to 8% (W+) in 2050. Both droughts and floods will be more intense. Minimum discharges will be lower in 2050: mean annual minimum (summer) discharge at Lobith (the Dutch-German border) is projected to decrease by 10% (G+) to 17% (W+). Maximum discharges will be higher: mean annual maximum discharge at Lobith is projected to increase by 2% (G+) to 6% (W+) (16).
Climate change has a much larger impact on discharges and droughts of the Rhine at Lobith than extreme changes in land use (30). Rhine river droughts at Lobith will be more common in 2050 with an increase of 117% (G+) to 197% (W+) in the drought duration. The severity of drought events will also increase. In this study a drought is defined as the Rhine discharge at Lobith being lower than 1265 m3/s (= Q10, the 10% lowest Rhine discharges) (16).
Sometimes, Rhine river discharge in the summer may be too low to prevent salt water from penetrating the river outlet near Rotterdam, causing problems for the intake of fresh water for drinking water production, agriculture, industry, and flushing the ditches (2).
Water shortages in the summer are lowest in the polders near the lake IJsselmeer, due to a lot of groundwater seepage, and highest in the sandy higher grounds. At present there are already too little options for sprinkling from groundwater and surface water at certain locations in dry summers; this problem will be worse in the future (2).
Vulnerabilities – Stability of flood defences
A lot of the dikes near canals and lakes in the low-lying parts of the Netherlands are made out of peat. These dikes were constructed in the course of hundreds of years. During the dry summer of 2003 one of the dikes burst, and several houses behind the dikes were flooded. It appeared that the drying-out of peat dikes makes them too light and unstable to withstand the force of the water. Therefore, the water level in the canals and lakes near these dikes needs to be kept sufficiently high in order to avoid drying-out of these dikes (1).
Vulnerabilities - Agriculture
In dry summers production losses in agriculture result from the crops not being able to evaporate the amount of water that is needed for optimum growth. This is due to the fact that sprinkling facilities are not designed for these conditions and the withdrawal of groundwater for irrigation in dry summers is strictly regulated. Besides, the sprinkling capacity in especially the western part of the country cannot be used fully when the surface water becomes too salt, which is the case when there is not sufficiently fresh (river) water available to wash down the seepage of salt water in the low-lying polders. In effect, in dry summers water with a relatively high salt concentration is let in into the ditches in order to maintain the water level in peat areas (1).
At present, in dry summers the loss of production with respect to optimum growth is 5-35% (10% on average); according to an assessment carried out in 2005 this equals an average annual financial loss of € 675 million (14). This loss is considered ‘a fact of life’ and not as damage. The extra loss due to extreme dry conditions results in ‘real’ damage, though: on average annually some € 180 million, and up to € 1800 million in an extremely dry year. These numbers should be corrected, however, for positive effects of lots of sun: according to the 2005 assessment the corrected damages are an average annual damage of € 150 million, and up to € 700 million in an extremely dry year (14).
Future water shortages for agriculture depend on future agricultural area, future prices for agricultural products, and the rate of climate change. Agricultural area will probably be some 18% less in 2050 (3, 4). It is estimated that the economic value of crops will be 20% less in 2020 for most crops and 10% for capital-intensive crops (no data are available for 2050) (5, based on 3, 4). It is estimated that more water is needed to maintain the present agricultural yield because the negative effect of the shortage of water in the root zone overrules the potential yield increase due to more evaporation.
All in all the water shortages probably will not increase between now and 2050. An increase is to be expected, however, in case a dry climate change scenario unfolds (1). In this case, the damage due to salination of groundwater and surface water is far less than the damage due to water shortage (2).
Average annual damage to agriculture due to droughts could increase during the 21st century from the current € 0,4 billion to € 1,1 billion (17).
Vulnerabilities – Nature
Aquatic ecosystems may be affected by low oxygen levels, high salt concentration and water temperature, too little dilution of pollution, and the risk of botulism and toxic cyanobacteria. Terrestrial ecosystems may be affected by low ground water levels. In the Netherlands, (terrestrial) ecosystems are vulnerable to droughts because they are adapted to man-made conditions. Under more natural conditions the impact of droughts to ecosystems would be less than the present situation (1).
Because of higher temperatures the evaporation and water demand of terrestrial nature will increase. On the other hand, the increase of CO2-concentration will reduce water demand. The balance between the two cannot yet be quantified. The impact of changes in precipitation, evaporation, river discharge and sea level rise on water shortages varies between a 3% reduction and a 5% increase, depending on the scenario chosen. The change in case of a dry scenario is smaller for nature than for agriculture because water demand by nature depends on ground water level in the spring: precipitation in the winter is projected to increase. Based on the expected future increase of nature area in the Netherlands by 60%, water demand by terrestrial nature will increase. Water demand will also increase for aquatic nature, due to an expected increase of aquatic nature area, and because more water is needed to maintain water levels in peat areas and to wash down the ditches (1).
The low-lying parts and the higher grounds are affected in different ways. In the low-lying parts there will be enough water but the quality may be a problem. In the higher grounds water availability may be a problem because these grounds are not connected to the major surface waters (2).
Vulnerabilities – Shipping
In the Netherlands, inland shipping contributes about 30% to the total transport of goods. At low Rhine and Meuse river discharge shipping is hindered because ships cannot be loaded to their full extent. More passages are needed to transport the same volume of goods and ships have to wait longer at sluices because of higher navigation intensity. All of this results in higher economic costs for society as a whole (1). Probably, problems due to the navigation channel being too shallow will occur on the German Rhine first before they are a fact in the Netherlands (2).
In the most extreme scenario of climate change that is used in Dutch assessments on the impact of climate change, transportation costs by inland shipping are expected to increase by 9% to 23%. This is due to increased occurrences of extreme high and low water levels. In the worst case scenario, a 10-day period with the lowest water level, the decrease in transport capacity is up to 28% in all inland navigation to and from the Netherlands. These percentages could be substantially higher on specific corridors between Rotterdam and Germany. Of this decreased capacity, 88% will shift to rail transport and 12% to road transport. A shift from the Port of Rotterdam to other European seaports is expected to be low, except in prolonged dry periods (13).
In an assessment carried out in 2005 the damage to inland navigation in dry summers has been estimated as on average some € 70 million annually, and up to € 800 million in an extremely dry year (14).
Vulnerabilities – Cooling water for power plants
Over the last 100 years, river water temperature has risen by 3⁰C in the Netherlands, and temperature will continue to rise by another 1-3⁰C until 2050. Sometimes in dry summers, the amount of water needed to cool power plants is insufficient because, for ecological reasons, there are restrictions with respect to the temperature of the water that power plants are allowed to discharge into the rivers (1).
It is estimated that well over half of the temperature increase of 3⁰C of the river Rhine in the last century is due to the increased use of cooling water, and the rest is due to climate change. Water temperature will continue to increase, and the potential for using Rhine water as cooling water for power plants will reduce (1).
If the scenario of fast climate change unfolds, cooling capacity in dry summers may be restricted to such an extent that the electricity production in the country may be jeopardized and the industrial production may be hindered significantly (2).
Vulnerabilities – Drinking water
At a number of locations drinking water is extracted from surface water. Basins for drinking water have been built to avoid shortages of water of good quality, which might happen during low river discharge. The size of these basins is such that a shortage of drinking water during dry summers is extremely unlikely in the Netherlands (1). The industry will become less dependent on groundwater or surface water because of an increase of the use of technology for water recycling (2).
Vulnerabilities – Recreation
Water shortages in the lakes and canals may affect the quality of the water for swimming, the navigability (too shallow), the quality of the fish stock, and the waiting time near sluices (1).
Vulnerabilities – Urban areas
In urban areas fresh water is needed to wash down the water in the canals and maintain water of a sufficiently high quality. Besides, the water level in urban areas needs to be maintained to avoid instabilities of foundations (1). It is estimated that the foundations of about 140,000 houses in the Netherlands suffer from low groundwater tables (8) and that about one third of the historic buildings in the country are vulnerable for droughts (9).
Sinking ground water levels damage the foundation of buildings. Too low ground water levels have already caused over € 5 billion of damage to foundations and buildings. During this century this may increase up to a total amount of € 40 billion is no measures are taken to stop this (17).
Vulnerabilities – Infrastructure
Droughts may result in damage to infrastructure through low groundwater tables. Railways and roads may subside, sewage pipes and cables may break, and wooden foundations may rot when exposed to the air (2).
Adaptation strategies - EU
EU policy orientations for future action
According to the EU, policy orientations for the way forward are (15):
- 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.
Water managers need to consider water shortages in the plans for the future. In The Netherlands, a guideline has been developed to help water managers to do so (6).
Several adaptation strategies can be adapted to reduce the impact of droughts: strategies to reduce water demand, to use water more efficiently, or to increase water availability.
Adaptation strategies – Water demand
Citizens can be stimulated to use water more efficiently by raising their awareness about the amount of water that is needed to produce the goods they use or the food they consume (the so-called water footprints). Also, serious games can be used to visualize water management issues related to, for instance, droughts (11).
Adaptation strategies - Agriculture
The impact of water shortages is highest for agriculture and nature, and small to negligible for the other interests. Measures to improve water supply for agriculture, and that may be beneficial in terms of costs and benefits, are enlarging water storage facilities, creating more facilities for sprinkling, and several small scale measures (1). An innovative technique for more efficient water use in agriculture is real time monitoring of the moisture content of the soil in connection with a decision support system for irrigation (11).
Large-scale facilities for storing water are not considered to be cost-effective. Water demand may be reduced by growing different types of crops and by rearranging agricultural areas. Large-scale infrastructural measures to redistribute water supply across the Netherlands are not recommended from a cost-benefit perspective; a large part of the water shortages for agriculture should be accepted as part of natural variation (1). Possibly, the infiltration of fresh water in rainy periods can be stimulated to create extra groundwater reserves for the summer (11).
Within the Netherlands, water shortages are highest in the southwest and in the northeast. In these areas the possibilities for sprinkling and irrigation are limited because of the high salt concentration in surface and seepage waters (1).
Adaptation strategies - Nature
Supplying water from one area to another may help agriculture. It may not be a good solution for drought in nature areas, however, since the quality of that water may not suit the specific conditions of nature. For nature, measures should be designed that make nature areas more robust with respect to droughts. Measures to overcome the impact of droughts for especially nature areas may be extremely expensive (billions of Euros) (1).
Adaptation strategies - Stability of flood defences
Currently, the stability of flood defences is the number one priority for fresh water supply in the Netherlands and policy is such that there will not be a shortage of water to secure the dikes. This will not change in the future. Measures for additional water supply, therefore, are not needed (1).
Adaptation strategies - Cooling water power plants
The amount of water needed to cool power plants in dry summers cannot be increased by water management measures. Instead, in the future locations near the coast may be preferred for new power plants whereas old power plants near the rivers may be shut down (1), and alternative cooling capacity such as cooling towers may build (2).
Adaptation strategies – Drinking water
The water shortages for drinking water supply are negligible and no additional measures need to be taken (1).
Adaptation strategies - Shipping
The vulnerabilities of shipping for the consequences of climate change cannot be overcome by large-scale infrastructural measures cost-effectively. The best option is to use smaller vessels or to transport less load.
At present, there is no need to take measures for shipping in view of the consequences of climate change. If the climate appears to change faster than current projections indicate, adequate measures can still be taken in time (1).
Some promising solutions for the consequences of climate change for inland navigation are (13):
- River management: Waterway improvement and canalisation of the RhineWaterway. The improvement can be carried out by dredging and construction of structures such as groynes, fixed bed layers, bottom vanes, bendway weirs and longitudinal dams. This measure may increase the navigation depth by 10 to 50 cm.
- Logistic management: Increasing the resilience and flexibility of the sector by modifying the supply chain. This can be accomplished by providing larger stock or storage capacity, alternative routes, other transport modalities, extra cargo handling facilities in ports and terminals.
- Information management: ICT systems for inland shipping and the use of ICT in the waterway (Smart Waterways). The use of ICT systems for inland shipping can lead to a better exchange of traffic and cargo information. Navigability can be improved by providing up-to-date on-line information on current and expected water depths in the shipping route, expected bed topography, as well as real-time draught and trim of the vessel. Use of ICT in the waterway shipping would contribute considerably to managing navigability (approximately 20 cm increase in depth).
- Fleet management: Using vessels with a smaller draught. These vessels can be constructed of light weight materials and or extra (temporary) buoyancy and they may be wider and longer.
Adaptation strategies - Recreation
The volumes of water that are needed to prevent botulism and toxic cyanabacteria cannot yet be quantified. A qualitative assessment has shown that adequate measures at most of the critical locations in the Netherlands are hardly possible from a technical point of view (1).
Adaptation strategies – Combating salt intrusion
The intrusion of salt water near sluices can be restricted by using bubbles of air that separate fresh water from salt water. These techniques are already used near several sluices in the Netherlands (11). The intrusion of salt groundwater can be restricted by infiltrating fresh water into the subsoil that acts as a hydraulic barrier against penetrating seawater. This innovative technique is already used in Barcelona since 2007 (12).
Adaptation strategies - Priorities in water supply during droughts
During droughts in the Netherlands there is not enough fresh water of sufficiently good quality to supply all the interests at stake with the amounts of fresh water they need to function optimally. The interests are prioritized, therefore, in the order of importance/vulnerability so as to make sure that the water supply for the most critical/vulnerable interests are secured. The prioritization in order of decreasing vulnerability is shown below (7):
Category 1: Flood protection and the avoidance of irreversible damage
- Dike stability
- Peat compaction
- Nature (for certain soil types)
Category 2: Utilities
- Drinking water supply
- Energy supply
Category 3: Small-scale high-quality use
- Sprinkling of capital-intensive crops
- Industrial use
Category 4: other interests
- Nature (in case of no irreversible damage)
Within the categories 1 and 2 there is also a prioritization. Within the other categories the prioritization is made to restrict the economic and social damage as much as possible.
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.
- Ministry of Transport, Public Works and Water Management (2005a)
- Deltares (2011)
- LEI (2003), in: Ministry of Transport, Public Works and Water Management (2005a).
- CPB (1996), in: Ministry of Transport, Public Works and Water Management (2005a)
- RIZA (2004), in: Ministry of Transport, Public Works and Water Management (2005a)
- Ministry of Transport, Public Works and Water Management (2009)
- KMPG/Grontmij (2001), in: Deltares (2011)
- Deltares (2010), in: Deltares (2011)
- Görgen et al. (2010)
- Deltares (2011)
- Teijón et al. (2009) in: Deltares (2011)
- Krekt et al. (2011)
- Ministry of Transport, Public Works and Water Management (2005b)
- Commission of the European Communities (2007)
- Bergsma et al. (2008)
- Ministry of Infrastructure and the Environment, and Ministry of Economic Affairs, Agriculture and Innovation (2012)