Finger in the Dyke

Collective Disaster Reduction

When I moved to Canada, I was surprised by the number of people who – as soon as they found out about my Dutch background – jokingly told me The Famous Story of a little boy who put his finger in the dyke. I am almost ashamed to say and disappoint many of you, that I have heard more about this boy in my years abroad than during my years at home.

Growing up in the Netherlands I always thought we were globally known for living below sea level, because we were the only ones, I thought, and it sounded like such a great idea to create land out of water. But what does that mean for the vulnerability of a community, how do they cope with this idea of collective disaster reduction?


The Netherlands has a population of slightly more than 16.5 million people, and a landmass of 41,000 km2, resulting in a population density of 399.7/km2.  This is about the same landmass size as Vancouver Island in front of Canada’s BC coast, however the island has a population of only 740,000 ( Close to 50% of the Dutch population and 80% of the country’s GDP is based in three out of twelve provinces, an area also known as The Randstad, which is located in the most vulnerable parts of the country: the parts that are located below sea level.

The Randstad: an urban area located below sea level (blue areas in the map at the right hand side are located below sea level). Source:

 Ultimate Disaster Reduction Tool

Dykes to me are the ultimate example of a collective disaster reduction tool. The Netherlands is rare in how it copes with the high vulnerability of large parts of the country that are located up to 7 meters (23 feet) below sea level. What many of you may not realize is that you might have been there: the airport Schiphol, the third largest passenger terminal in the world, is located at one of the lowest parts of the Netherlands: 6.7 meters (22 feet) below sea level. This is an important issue in a time where community vulnerability and collective mitigation efforts seem to gain importance because of the growing population and the number and impacts of hazards influenced by climate change (Van Aalst, 2006). The Netherlands has collectively created a disaster reduction tool: the Dutch Sea Dike System. The sea dikes are in place to protect the Netherlands for flooding from the North Sea, located at the West of the Country.

A Community Formed By a Mutual Fight Against Water

With a coastline of 450km with the North Sea at its North and West side (see figure 2 for more topographical details), the Netherlands are known for their continuous fight against the water. Which is ongoing for centuries and which was the foundation of the nation as it is right now: the basis for the Dutch democracy is founded in the Water Boards. The first Water Boards were established during the 14th century when farmers decided to cooperate in building dikes to protect their land. ( Nowadays the responsibilities of the Water Boards cover the management of dams and dikes, the level and quality of the ground water table and surface water bodies, regional water management, treatment of waste water and environmental related issues.  Throughout its history the country has had an open-economy and has always used its waterways and the North Sea for transportation of its trade products which explains why the most densely populated parts of the country are near the coast.

The Dutch Continuous Sea Dike System

The Dutch sea dike system forms a continuous network together with the dunes all along the 450km long coast with the North Sea. At several places special waterworks, such as the Delta works in the province of Zeeland (“land of the sea”) and the locks near Rotterdam, are brought into place to increase the resilience capacity of the system. An important advantage of the dikes is that they foster long-term mitigation and resilience and provide equal protection for everyone in the Dutch society. The dikes as a tool of resilience are not only part of the mitigation and preparedness stages of the disaster cycle (see appendix A) but also make life possible as without them the land behind the dikes would be flooded up till the city of Utrecht, in the middle of the country, east of Amsterdam.

The Dutch sea dykes are designed according a so called “probabilistic design”. Flooding is being perceived as a ‘high consequence low-probability’ event; these statistics have been combined with reliability models and the acceptability of flood risks to derive the safety levels. The acceptable level of risk for society and cost-benefit aspects of a certain activity are based on criteria set for national risk levels and are then calculated for local levels and activities (; and Berendsen, 2005).

Safety measure norms per dike ring area (from 1/10.000 years to 1/1250 years). Source: HVN, 1998.

Legislation and Adaptation to Climate Change

Throughout the years the Netherlands has had several acts and legislature that aim for integrated water policies. For example the Water Management Act form 1989 concerning planning for water management combines not only national and provincial plans but also spatial as well as environmental planning. One of the unique aspects of the Dutch coastline legislation is the safety measure which the government adopted for its dikes and dunes (water level fixed at 5m+NAP[1] with a return period of 1/10.000 per year).

The Delta committee (2008) explains that in her Delta Program she bases her recommendations and estimations of required investments at a relative sea level rise of 0.65 to 1.30 meters for 2100 (these numbers include the effects of the subsidence of the western part of the country and are derived from IPCC data). The costs associated with the Delta Program for investments during the years 2010 to 2050 will be about 1.2 and 1.6 billion Euros.  Natural values of the coastal system will be taking into account as ‘building with nature’ is the credo for the developments until 2050 as suggested by the Delta Committee.

Flooding and Hazard Mitigation in the US

In the city of Tulsa (OK), flood records are being kept since the 1900’s and the Arkansas River that crosses the city has caused many floods. During the sixties levees were built to protect the oil refineries, however during the late sixties and the seventies the perception of the residents of Tulsa changed which led to the ‘regulatory era of floodplain management’. The problem of flood control structures only protecting a specific site was recognized as well as its tendency to give a false sense of security. In contrast to other cities at the time, the city of Tulsa decided to clear its floodplains and widen them to secure and restore the flooding mitigation service of floodplains. After the 1976 elections the new commissioners also implemented new regulations that aimed to make developments in the floodplains impossible and other developments were restricted to drainage criteria and stormwater detention regulations. In 1978 the ‘Non-structural Era of Stormwater Management’ was marked by the Water Policy initiative. This meant a focus on preserving the natural values of the wetlands and floodplains. Structural flood control techniques were equally valued as non-structural flood control techniques. (Patton, 2009 and  According to Patton (2009), the Tulsans always tended to perceive the floods as something they had to ‘endure’. To me  this is a great example of dealing with water in the opposite way of how the Netherlands does it: the Tulsans have found a way to live with nature, accepting how it can interrupt humans’ everyday life, rather than trying to conquer it as the Dutch do.

 Map of Tulsa and the Arkansas River.

Implications for other Flood-Prone Communities

I strongly believe in the power of collective disaster reduction, but admittedly, and sadly enough, the Dutch example can’t be copied “just like that” to other low parts of the world such as Bangladesh. The way The Netherlands is approaching this duality between a very high population density mostly located in the most vulnerable parts of the country, is by emphasizing living together with the water rather than trying to conquer it, but nonetheless its approach is very different from the Tulsans’. I would encourage researchers to come up with an approach integrating both ideas of living with water, to provide hazard mitigation to other flood-prone communities in the world where the financial means and the history of living with water are more challenged.

Author: Marleen C. de Ruiter


Why focus on post-disaster community recovery?

Lessons to be learned

It has only been two years since I visited the Mississippi Gulf Coast to study its community recovery after Hurricane Katrina (2005) and the BP Horizon Oil Spill (2010) struck the area. In cities such as Biloxi and Gulfport, impacts from hurricane Katrina and the oil spill were still visible and the recovery process ongoing. The disaster literature often neglects to discuss the recovery of the natural environment in urban areas and how this influences the economic recovery of a community. This is caused in part by the difficulty of measuring recovery.  However, despite its difficulties, it is a very important part of the post-disaster recovery to explore such ‘hidden losses’ as a declined contribution of a local fishery industry to its community but also to take lessons for the future to improve communities’ disaster preparedness and resilience.

Post-disaster recovery is one of the least studied topics within the research field of natural hazards and disasters (Comerio, 2005; Mileti, 1999; Rubin, 1985). However, the increased occurrence and severity of natural hazards as well as the increased vulnerability of disaster prone areas make the assessment of natural hazards and post-disaster recovery an urgent issue.

The pressure of humans on their environment is growing and this underscores the importance of how we assess recovery and mitigation efforts with regards to these natural systems in the post-disaster period. The impacts of global climate change, as caused by humans, on the risks of weather-related natural disasters has well been established.  More specifically, the predicted global warming will likely influence the severity and the number of weather related hazards such as heat waves, floods and hurricanes. The overall vulnerability of a community depends on its capability to deal with the changed situations in weather and climate, but the likelihood of these meteorological events happening is increasing (Van Aalst, 2006; Keller and Blodgett, 2009).

Munich Re (2007) writes in its annual report that the economic costs associated with the impacts of natural hazards are increasing every year. Densely populated areas are often found near or are part of hazardous areas. Moreover, according to the Center for International Earth Science Information Network at Columbia University, 40% of the world’s population lives in coastal areas, defined as the area within 100km of the coast (CIESIN). Secondly, the value of the built environment as well as the intrinsic value of the natural systems is increasing. The increase in the economic costs is caused by humans’ growing dependence on technology and the growth in the value of the built environment and the increasing appraisal of the intrinsic value of ecosystems is caused by the pressure of both climate change and the expanding human population on the natural environment (Munich Re, 2007).

In Biloxi, it appeared that their tourism sector, in the study used as a proxy for their general economic recovery, recovered more easily after Hurricane Katrina than their environment dependent, fisheries sector. Besides assessing the changes in their economy, I also learned that there are many lessons to take from the disasters that hit the Gulf Coast in 2005 and 2010 and that are likely to continue to hit the Gulf Coast. Several of the recommendations made by the experts encourage the development of pre-disaster preparation plans in terms of training, education and mitigation. Putting into place pre-disaster building codes and maintaining those updates can decrease the damage caused by a Hurricane. An important issue raised by several of the experts is the importance of communication with the local community. They explained the importance of communicating the predicted storm track and the potential damage that can be caused by a Hurricane in order to decrease the number of people staying behind. I think that the response to Hurricane Isaac last month shows that the community, practitioners and policy makers have taken those lessons to heart. This increase in awareness and pre-disaster preparedness has also been accompanied by an increase in available information which contributes to the learning process.

Google has developed Crisis Response, a set of tools that allow everyone, practitioners, researchers and  communities to keep track of an occurring disaster (find the Google Crisis Map for Isaac here). It would be great if someone would make a tool available that also tracks all the different elements of post-disaster community recovery. I wish I could go back to the disaster struck communities in the Gulf Coast and show them how far they have come and what a great job they did in their post-disaster community recovery process.

Author: Marleen C. de Ruiter


– Google Crisis Response:

– De Ruiter, M.C., Post-Disaster Community Recovery: Linking Environmental and Economic Recovery, MSc Thesis, University of British Columbia, 2011.