Proceedings of ICE Civil Engineering 164 August 2011 Pages 114–121 Paper 1000039

doi: 10.1680/cien.2011.164.3.114 Keywords floods & floodworks; coastal engineering; river engineering How the Dutch Marcel J. F. Stive MSc, PhD is professor of hydraulic engineering at plan to stay dry over Delft University of Technology, Delft, the the next century

Louise O. Fresco MSc, PhD Over two-thirds of the Netherlands’ economy and half its is professor of sustainable development at the University of Amsterdam, Amsterdam, population is below sea level. The Dutch government recently set the Netherlands out far-reaching recommendations on how to keep the country flood-proof over the next century given the likelihood of rising sea Pavel Kabat MSc, PhD levels and river flows. This paper explains the recommendations, is professor of earth system science and climate studies at Wageningen University, which are based on a gradual upgrading of safety standards in Wageningen, the Netherlands the light of economic growth and group casualty risk, together with triggers provided by debates and data on climate change. Bart W. A. H. Parmet It concludes that protection is feasible both technically and MSc is the director of Deltaprogramme and economically, costing up to €3 billion a year, and that the approach the Support Team Delta commissioner at the Ministry of Infrastructure and the could be useful for other low-lying areas. Environment, The Hague, the Netherlands

Cees P. Veerman The Netherlands is a densely populated mendations on making the country PhD country with a prosperous, open econo- flood-proof for the next century (Delta is professor of agribusiness at the University my situated largely in coastal lowlands. committee, 2008). In addition to flood- of Tilburg, Tilburg, the Netherlands The Dutch North Sea coast is about 350 ing it also considered river levels and km long and most of the population lives fresh water availability. This paper pre- directly behind the coast in low-lying areas sents and discusses some of the findings. below sea level. This region is the centre of the nation’s economy, with nearly 9 mil- Potential damage from flooding lion people protected by dykes and dunes along the coast, main rivers and lakes, and The Central Bureau for Statistics Neth- roughly 65% of gross national product – erlands estimates the national wealth as around €350 billion – generated here. five times the national income, without The major harbours and airports on or taking account of ecological, landscape near the North Sea are vital nodes in the and cultural values (Van Tongeren and country’s international transport network Van de Veen, 1997). Based on this defi- as well as important locations for the nition, Dutch national wealth was about goods and services industries. €2750 billion in 2007. Since an estimat- The Netherlands has a long and varied ed 65% of this wealth lies in flood-prone history of coastal and river flood man- areas, the total wealth potentially under agement. The anticipation of accelerated threat due to flooding is of the order of climate change during the twenty-first €1800 billion. century has renewed the demand for sus- The actual economic damage from tainable solutions to coastal vulnerability. the failure of the flood protection system In September 2008, a committee set has been estimated as €10–50 billion for up by the government in September each individual area protected by dykes 2007 delivered a number of recom- – referred to as ‘dyke rings’. There are 53 Delivered by ICEVirtualLibrary.com to: CIVIL ENGINEERING IP: 131.180.64.184 On: Sat, 06 Aug 2011 16:26:33 How the Dutch plan to stay dry over the next century

dyke rings in the Netherlands, with pro- Flood probability that dyke tection levels at 90% probability of resist- ring has 90% probability ing design water levels that vary between of withstanding 1:10 000 and 1:1250 probability a year 1:10 000 per year (see Figure 1). This implies flooding prob- 1:4000 per year ability varies between 1:100 000 and 1:2000 per year 1:12 500 a year. With the identification of 1:1250 per year failure mechanisms other than wave over- topping and/or overflow, notably piping High ground (also (e.g. New Orleans), there is now a strong outside the Netherlands) debate on how realistic these flooding Primary water defence outside the Netherlands probability figures actually are. As such, the government’s Delta com- mittee (2008) suggests that the design water level probabilities should be inter- preted as flooding probabilities for the time North Sea being. Recent insights of flooding scenarios (Jonkman 2007, 2008) indicated that it is most unlikely that the major dyke rings will be inundated completely. The location of a dyke and the physical circumstances under which it is breached will make a marked difference in the resulting economic dam- age. Also, the damage caused by a flood depends on the size of the area inundated, the water depth in that area and the dura- tion of the episode. Aerts et al. (2008) estimated the eco- GERMANY nomic damage from flooding through all dyke rings as approximately €190 billion, based on differentiation according to BELGIUM water depth per dyke ring. This concerns both direct and indirect damage. The estimated future potential damage would 0km50 increase to €400–800 billion in 2040 and €3700 billion in 2100 in the absence Figure 1. Current legislated flood protection levels in the Netherlands’ 53 ‘dyke rings’ – more of any measures, given a sea level rise of economically important areas have up to four times the protection of some rural areas 0·24–0·60 m in 2040 and 1·5 m in 2100. The factors that govern calculations of estimated future potential damage are coastal management. Whereas in the past advocated working with nature in any economic growth combined with indi- the challenge was formulated to ‘fight’ the future flood protection project in estua- rect damage. Prior to hurricane Katrina, forces of nature, it is now recognised that rine and coastal environments. A num- potential damage in New Orleans was many issues other than protection against ber of their recommendations exemplify estimated at US$16·8 billion or €12·3 flooding have to be accommodated – par- this: ‘If there is still is a choice, leave billion. After the 2005 storm hit, direct ticularly ecological issues. untouched estuaries and deltas alone’; ‘If damage to dwellings, government build- Water and coastal management have there is already a history of human inter- ings and public infrastructure alone was become interdisciplinary as well as vention, try to adopt the most flexible US$27 billion or €19·7 billion (IPET, transdisciplinary (Waterman, 2008). approaches to safety and development’; 2008), illustrating that it is essential to Some of the issues and dilemmas and ‘Reversible and local measures update economic growth and indirect involved in this challenge are illustrated within the limits of the natural processes damage figures regularly. by the following examples. are preferable’. The recommendations regarding work- Paradigm shift Working with nature ing with nature are in line with today’s In a critical evaluation of the morpho- policy, for example maintaining the coast- Implementing the Delta committee’s logical, ecological and socio-economic line with ‘soft’ solutions rather than hard recommendations will require a paradigm effects of the Delta project following the concrete barriers. Nevertheless, imple- shift in the Dutch approach to water and 1953 flood disaster, Saeijs et al. (2004) menting the recommendations appears Delivered by ICEVirtualLibrary.com to: issn 0965 089 X ProCIP:eedings 131.180.64.184 of the Institution of Civil Engineers – CIVIL ENGINEERING, 2011, 164, No. CE3 115 On: Sat, 06 Aug 2011 16:26:33 Stive, Fresco, KABAT, PARMET and VEERMAN

to be complex. For instance, sea dykes insight for an optimum solution. They The Dutch decided to base their answers may hamper natural processes, but from must also recognise that they are not in to these questions not merely on the an economic viewpoint it is generally not competition with the approval process, fact that storms are destructive and the justifiable to remove dykes, let alone from but complementary to it’. Netherlands low, but also on quantitative a socio-emotional perspective. economics. With the help of renowned The complexity is further illustrated by The approach is of even more impor- Dutch mathematician David Van Dantzig the conclusions of Jonkman et al. (2005), tance in the view of the long-term per- (1956), the 1953 task force calculated which set out lessons for the Netherlands spective that needs to be the basis of any safety levels using an equation that is from the New Orleans flood disaster of coastal and water management recom- now widely used by most engineers 2005. This highlighted a tendency in mendations, because many physical fea- Dutch policy to head towards the US tures, such as dune ranges and estuaries, risk = probability of failure × model of mitigating consequences instead as well as socio-economic values change projected cost of damage of strengthening flood defences, with at the scale of centuries. prevention of floods receiving gradually This kind of risk analysis is common and relatively less attention. Arguing that Background to committee today in fields like nuclear power, aero- protection standards were over 40 years space and chemical manufacturing. old and had not evolved with the increase The recent Netherlands Delta com- Back in the 1950s, however, account- of economic value of protected areas over mittee was not established in response ing for the projected cost of damage time, and that societal risks associated to a flood disaster, unlike previous state when developing flood protection was with flood defences on a national scale committees, which were established novel. The power of the simple formula were larger than in other aspects of Dutch after severe floods hit the country in is that it produces economically rational society (Ten Brinke and Bannink, 2004), 1916 and 1953. It was triggered by the public-safety decisions: less value, less the authors concluded a fundamental debate in the Netherlands on the delay protection (costs of human casualties are debate on required safety levels of Dutch in bringing safety up to the standards not taken into account directly). Dutch flood defences was necessary. laid down in the Flood Defences Act law now requires the principle to be (Kingdom of the Netherlands, 1996), used to determine the strength of flood Interdisciplinary and transdisciplinary the 2005 flooding of New Orleans and defences throughout the country. approaches the debate on climate change. In the case of the dyke ring protecting Coping with such dilemmas is an The committee’s work demonstrates the province of South Holland, an eco- example of the major challenges cur- the importance of a wide-ranging, long- nomically vibrant area, against flooding rently facing the Dutch government. It term preventive approach. Its recom- due to extreme storm surge levels and/or illustrates that ‘working with nature’ mendations are based on the necessity extreme river discharges, a safety level of does not just imply using natural sciences to upgrade safety standards in the light 1:10 000 is called for. More rural parts – it involves a range of different disci- of economic growth and group casualty of the country are required to have safety plines and requires a transdisciplinary risk, meaning that the country has ‘more levels of just 1:1250 or lower (see Figure approach. to lose’. 1). The underlying principle that leads to The water problem in the Netherlands The committee underpinned the basic the variable levels of protection is Van is unstructured: different actors have dif- risk approach introduced by the first Dantzig’s economic optimisation crite- ferent perspectives, uncertainties are large Delta committee of 1953. The most rion (Van Dantzig, 1956): strive towards and relevant knowledge is under debate. important conclusion is that the protec- minimal societal costs summing the Typical characteristics that, according tion of the Netherlands, with two-thirds protection investment and the potential to Hoppe and Huijs (2003), ask for a of its economic value and half of its pop- estimated damage. transdisciplinary approach are a specific ulation positioned below sea level, is fea- The corollary is that, although not type of interdisciplinarity, transgressing sible, both technically and economically, all Dutch citizens may be aware of it, borders between disciplines and integrat- if planned in a long-term and flexible their government has accepted – even ing knowledge and perspectives of differ- manner. Such an approach could provide legislated – unequal protection, or what ent scientific disciplines and non-scientific useful elements for other low-lying areas. engineers euphemistically call ‘differen- sources (Pereira and Funtowicz, 2005). tiation’, based on the fact that all places An example of the practical implica- Risk approach cannot be protected up to the same tions for coastal engineers is formulated The mega structures, such as storm standard and individual cost must be bal- by Kamphuis (2006). surge barriers, introduced by the first Delta anced against collective cost. committee were innovative and impressive, The USA certainly has variable protec- ‘They must participate. They need to but what may prove to be the most vision- tion levels throughout the country, but understand, discuss and explain uncer- ary aspect of the is the statisti- there is a difference between de facto dis- tainties openly and clearly. They must cal approach that guided the designs. parity and an explicit government policy realise that they do not provide some How high should the levees be built? of inequality. Imagine if the US Congress final proof, but only the best possible How strong should a surge barrier be? or the Army Corps of Engineers were Delivered by ICEVirtualLibrary.com to: 116 ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERINGIP: 131.180.64.184, 2011, 164, No. CE3 issn 0965 089 X On: Sat, 06 Aug 2011 16:26:33 How the Dutch plan to stay dry over the next century

to recommend protecting the French 0km50 quarter and downtown New Orleans at the 1:10 000 year level while giving less economically productive areas such as Wadden St Bernard Parish only a 1:100 year level area of protection. Applying the Dutch model of risk-based design would be a political non-starter, if not unconstitutional, and the efforts of the Army Corps of Engi- Ijssel delta neers would in no time be halted by an North Sea army of lawyers.

Ijsselmeer Updating standards area The standards for safety from flooding Holland based on the risk approach need rethink- coast ing, however, because both individual Ijssel and group risk for casualties (deaths) due to flooding is much higher than due to other external risks (Jonkman 2007, Rijnmond 2008). That is why the Delta commit- Haringvlient tee recommends opting for an increase Upper reaches Greveling in protection level with a factor of 10, en which is estimated to be a minimum ‘no- Lower, tidal reaches Krammer– regret’ level to reduce the casualty risk. Eastern This implies that interpreting present Zoommeer legal risk levels as probabilities of flood- Western Sc Southwestern ing based on a full-risk approach should heldt delta vary from 1:100 000 to 1:12 500 a year.

Climate change To anticipate long-term developments, GERMANY BELGIUM the Delta committee sought to base its Scheldt recommendations on the most recent scientific findings. The committee there- fore asked a team of renowned national and international climate experts (among Figure 2. Location of the protected regions – specific recommendations have been produced for each whom were Intergovernmental Panel on Climate Change (IPCC) authors who contributed to the recent fourth assess- The figure is nevertheless relevant Standards of flood protection ment report; see Katsman et al., 2011; because it represents an extreme case Until 2050, the present standards Kok et al., 2008; and Vellinga et al., against which the committee could try to of flood protection of all dyke rings 2008) to deliver the best possible esti- answer the most relevant issue, namely: must be improved by a factor of 10. To mates of the expected global and regional can the Netherlands be kept flood-proof that end, new standards must be set (i.e. North Atlantic Ocean) sea-level rise under the most extreme scenario? That is as soon as possible (around 2013). In and rainfall intensity that give rise to why in the committee’s advice the high- some areas where even better protec- river discharge changes. end scenarios were considered, so that tion is needed, a ‘Delta dyke’ concept Their updated climate model results a convincing and science-based positive is promising – these dykes are either resulted in a probable range of upper answer (‘yes’) could be given. so high or so wide and massive that boundaries for the expected climate chang- there is virtually zero probability they es: sea-level rise along the coast in the year Committee recommendations will suddenly and uncontrollably fail. 2100 could reach as high as 0·65–1·3 m With regard to specific or local condi- relative to 1990, including isostatic move- A total of 12 recommendations were tions, this will require a tailor-made ment and subsidence. However, it is clear formulated: three generic and nine approach. All measures to increase the that the upper boundaries do not represent regional as follows (Delta committee, flood-protection standards must be the most likely probable situation in 2100, 2008). Figure 2 shows the regional loca- implemented before 2050. Post 2050, as has also been stated by the Royal Neth- tions and Figure 3 provides a graphic of the flood-protection standards must be erlands Meteorological Institute. the recommendations. updated regularly. Delivered by ICEVirtualLibrary.com to: issn 0965 089 X ProCIP:eedings 131.180.64.184 of the Institution of Civil Engineers – CIVIL ENGINEERING, 2011, 164, No. CE3 117 On: Sat, 06 Aug 2011 16:26:33 Stive, Fresco, KABAT, PARMET and VEERMAN

0km50 to nourish such large volumes must be investigated. After 2050, beach nour- Monitoring ishments continue – more or less sand Wadden Sea required, depending on sea level rise. North Sea Wadden Sea area Free discharge The beach nourishments along the at least Additional until 2100 North Sea coast may contribute to the supply adaptation of the Wadden Sea area to sea- level rise. The existence of the Wadden Sea area as known at present is by no means B Ijssel delta ea ch study assured, however, and depends entirely nou rish ments on the actual rate of sea-level rise in the coming 50–100 years. Developments will have to be monitored and analysed in an international context. The protection of the Additional fresh water island polders and the North Holland coast supply Implementation programme must remain assured. Rijnmond ‘Room for the River’ including long-term perspective study South-western delta: Until 2050, the Eastern Scheldt storm- Beach nourishment Int er surge barrier keeps its function. The dis- na tio advantage of the barrier is its restriction of na l co tidal movement and, as a result, the loss op Adaptation Krammer e ra Volkerak Zoommeer t of the intertidal zone. This is to be coun- io Flood protection Meuse n including long-term tered by additional sand nourishment from perspective (IVM) outside (as from the outer delta). After 2050, the life-span of the Eastern Scheldt BELGIUM n io t storm-surge barrier will be extended by a r Key e p technical interventions. This can be done o o Coastal reclamation by Lake level rise with c

l up to a sea-level rise of approximately 1 m beach nourishments accompanying measures/ a n o strategic fresh water i (2075 at the earliest). If the Eastern Scheldt Enforcement of flood t reservoir a n GERMANY defences due to sea level rise r storm-surge barrier is no longer adequate, e t Additional measures n Restoration of tidal to increase the level I then a solution will be sought that largely dynamics in Eastern Scheldt of protection restores the tidal dynamics with its natural Figure 3. Overview of the Delta committee’s national recommendations, which are expected to cost to estuarial regime, while maintaining safety €2·5–3·1 billion a year to implement up to 2050 against flooding.

New urban development plans a facilitating role in such areas as public South-western delta: The decision of whether to build in information, setting building standards This must remain an open tidal system low-lying flood-prone locations must be and flood warnings. to maintain the valuable estuary and the based on a cost–benefit analysis. This navigation to . Safety against must reveal present and future costs for North Sea coast flooding must be maintained by enforce- all parties. Costs resulting from local Until 2050, build with nature. Off the ment of the dykes. decisions must not be passed on to coasts of Zeeland, Holland and the Wad- another administrative level, or to society den Sea Islands, flood protection will be South-western delta: Krammer–Volkerak as a whole. They must be borne by those maintained by beach nourishments (see Zoommeer who benefit from these plans. Figure 4), possibly with relocation of the Until 2050, make sure that the Kram- tidal channels. Beach nourishments must mer–Volkerak Zoommeer, together with Areas outside dykes be done in such a way that the coast the and possibly also the East- New development in unprotected areas can expand seaward in the next century ern Scheldt, can provide temporary storage lying outside the dykes must not impede (effectively this implies reclaiming land of excess water from the Rhine and Meuse a river’s discharge capacity or future in the North Sea). This will provide great when discharge to the sea is blocked by levels of water in a lake. Residents and added value to society. Sand extraction closed storm-surge barriers. A salinity users themselves are responsible for such sites in the North Sea must be reserved gradient (a natural transition between fresh measures as may be needed to avoid in the short term. The ecological, eco- and salt water) in this area is a satisfactory adverse consequences. Government plays nomic and energy requirements needed solution to the water-quality problem and Delivered by ICEVirtualLibrary.com to: 118 ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERINGIP: 131.180.64.184, 2011, 164, No. CE3 issn 0965 089 X On: Sat, 06 Aug 2011 16:26:33 How the Dutch plan to stay dry over the next century

Figure 4. Beach nourishment will protect the North Sea coast as well as reclaim land for future use can offer new ecological opportunities. In this case, an alternative fresh water supply system must be developed.

The major rivers area Until 2050, the ‘Room for the river’ (see Figure 5) and Maaswerken pro- grammes must be implemented without further delays. Subject to cost-effective- ness, measures must be taken now to accommodate discharges of 18 000 m3/s from the Rhine and 4600 m3/s from the Meuse. In this context it will be neces- sary to conduct negotiations with neigh- bouring countries under the EU directive on the assessment and management of flood risks (EC, 2007) to harmonise the measures. Furthermore, room must be reserved and, if necessary, land pur- chased so that the river system will be able to discharge safely the Rhine and Meuse water. From 2050 to 2100, the measures to accommodate the Rhine and Figure 5. River Ijssel is part of the ‘Room for the river’ programme, which is designed to 3 Meuse discharges should be completed. accommodate an extra 22 600 m /s discharge from the Rhine and Meuse Delivered by ICEVirtualLibrary.com to: issn 0965 089 X ProCIP:eedings 131.180.64.184 of the Institution of Civil Engineers – CIVIL ENGINEERING, 2011, 164, No. CE3 119 On: Sat, 06 Aug 2011 16:26:33 Stive, Fresco, KABAT, PARMET and VEERMAN

Rijnmond (mouth of the river Rhine) administrative organisation and funding while for 2050–2100 it is €1·2–1·8 billion. Until 2050, this is to be an open sys- within the present political system and Including management and mainte- tem which can be closed in emergencies the current legal framework. This must nance, the total costs of growing with the (Figure 6). It offers good prospects for in any case include the delta fund and its climate and ensuring improved protection combining safety against flooding, fresh supply; the director’s tasks and authority; add up to €2·5–3·1 billion a year to 2050. water supply, urban development and nature the provision that a delta programme shall In absolute terms, this presents a huge development in the region. The extreme dis- be set up; regulations for strategic land monetary investment, but it translates to charges of the Rhine and Meuse will then acquisition; and compensation for dam- only about 0·5% of the current Dutch have to be rerouted via the south-western ages or the gradual loss of benefits due to annual gross national product. The cost delta. The fresh water for the western Neth- the implementation of measures under the of integrated water safety for the future of erlands will have to be supplied from the delta programme. the Netherlands is therefore far from being Ijsselmeer, and the necessary infrastructure unbearable. will have to be built. Room must be created Costs of implementation The central message of the committee is for local storage in deep polders. Further that the Netherlands can handle even the research into the ‘closable–open’ Rijnmond Implementation of the entire package of most extreme estimate of sea-level rise and system should be initiated soon. measures proposed by the Delta commit- river discharges that the scientific commu- tee – the Delta programme – is estimated nity estimates possible based upon current Ijsselmeer area to cost €1·2–1·6 billion a year to 2050 and knowledge. The recommendations of the The level of the Ijsselmeer lake will €0·9–1·5 billion a year from 2050 to 2100. committee are feasible in terms of time, be raised by a maximum of 1·5 m. This The summary does not include the annu- knowledge and economic means. will allow gravity-driven drainage from al sums for maintenance and management Moreover, the measures will result in Ijselmeer into the Wadden Sea beyond in relation to flood protection and fresh more than just safety – that is, if they are 2100. The level of the Markermeer lake water supply. At present, these add up to implemented sensibly they will lead to will not be raised. The Ijsselmeer retains approximately €1·2 billion a year for central more spatial quality, a more diverse nature its strategic function as fresh water reser- government, the water boards and prov- and other socio-economic values such as voir for the northern Netherlands and, in inces. The total costs of growing with the balanced urban and recreation develop- view of the progression of the salt tongue climate and ensuring improved protection ment, agriculture, fresh water supply and in the , for the western are €2·4–2·8 billion annually up to 2050. even possibly energy generation. And, if Netherlands. Until 2050, measures should A supplementary €0·1–0·3 billion a year sea level rises slower than expected, the be implemented to achieve elevated water will be required if the Delta programme’s approach allows the flexibility to delay level, which can be done gradually. The beach nourishment for flood protection is or temper measures and hence to adjust aim must be to achieve the largest pos- expanded so that 100 years from now the expenditures. sible fresh water reservoir around 2050. North Sea coast of Holland and Zeeland The measures needed to adapt the lower is extended seawards by, for instance, Discussion and conclusions reaches of the river Ijssel and the Zwarte 1 km to create new land for recreation, Water to a 1·5 m higher water level in nature and other functions. This brings The Dutch Delta committee recommen- the Ijsselmeer must be investigated. After the annual costs of the programme for dations became a matter of active, often 2050, depending on the phased approach the period 2010–2050 to €1·3–1·9 billion, passionate public, political and academic adopted, follow-up measures may be needed actually to implement a maximum The Hague 0km10 Gouda water level increase of 1·5 m. Storm Delft Lek surge Maeslant barrier Political-administrative, legal, financial The political-administrative organisation of water safety should be strengthened by providing cohesive national direction and regional responsibility for execution. Drecht Waal A permanent parliamentary committee cities on the theme should be implemented. Funding should be guaranteed by: creat- Flood water ing a delta fund, managed by the minister Meuse of finance; supplying the delta fund with

a combination of loans and transfer of Existing dyke or dune Existing dam Existing flood barrier (part of) the natural gas benefits; making Modified or new dyke or dune Modified dam New flood barrier national funding available and drafting rules for withdrawals from the fund. A Figure 6. Rijnmond (mouth of the Rhine) will normally be open but closed in the event of storm surges and/ Delta Act will anchor the political- or high river discharges using existing and new barriers to protect Rotterdam and surrounding urban areas Delivered by ICEVirtualLibrary.com to: 120 ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERINGIP: 131.180.64.184, 2011, 164, No. CE3 issn 0965 089 X On: Sat, 06 Aug 2011 16:26:33 How the Dutch plan to stay dry over the next century

debate. Do the recommendations sufficient- to start now, creating both a fund and set- planning and development. As a result, ly reflect highly uncertain future changes, ting up an implementation agency. It can the climate issue is gradually moving from especially in climate and sea-level rise? be done – at a slower or faster pace – over being perceived as a threat to become The Delta committee introduced a con- many years to come, along with good an opportunity. Together with innovative cept of plausible high-end sea-level rise monitoring of the actual rate of sea-level solutions, technologies and transitions, this scenarios, thereby testing the feasibility of rise, and taking into the account the latest presents a major opportunity to accelerate maintaining the defence strategy of the 53 scenarios of sea-level rise and river dis- transition of the country’s valuable and dyke rings, which turned out positive both charge. In this way, the uncertainty which highly exposed Delta into a more sustain- in technical and in economic terms. These is surrounding climate scenarios is not a able future. go hand-in-hand with no-regret, flexible reason for no action at all. As David Wolman (2008) in Wired and adaptive measures: step-wise flood The case of the Netherlands clearly expressed it, ‘Meanwhile, the water keeps protection adaptation measures which can illustrates that even with existing uncer- coming. The Dutch are taking on the be undertaken now and which are robust tainties about future climate, economically threat of global warming before anyone’s enough to accommodate future insights viable and responsible investments into feet are wet. They are showing the world about changing climate. An example of adaptation measures in the water sector that to prepare for sea-level rise and other such measures is beach sand nourish- and beyond can be made. If these anticipa- impacts of climate change, you need, para- ments along the coastline to protect it tory interventions are flexible, they can be doxically, not dominion-over-nature bra- from rising sea levels. implemented gradually and offer prospects vado but patience, good data, and – above The important point is not to wait, but for action in the short term in regional all – the long view.’

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