· · · Repository Hydraulic Engineering Reports

On the 28th of February 2010 at 2 a.m. the storm Xynthia hit the French Atlantic coast. The storm surge combined with the high tide and large waves caused flood defences to fail along the coastline from the Gironde (Bordeaux) to the Loire Estuary. A significant amount of land, (>50 000 ha) was consequently flooded and 47 people died as a result of the storm. Most people died due to the flooding (they drowned, were exhausted or died from hypothermia). A number of people died as a result of the storm itself (storm debris). The French departments of Vendée and Charente Maritime suffered the most. Some parts of the departments Gironde and Loire Atlantique were also flooded. Since 1953 the Netherlands has not had any experience with major floods. Large parts of the Netherlands are also prone to coastal flooding, even though we have very high safety standards. The Netherlands can learn from this flood in a neighbouring country with a common history and legal system. The foundation of the legal system in the Netherlands and France was laid down in the Napoleonic period with the introduction of the book on common law. Jurisprudence plays a minor role in Napoleonic law. The flood was not caused by natural phenomena alone, organisational failure plays a large role in understanding the flood. This book describes the Xynthia storm and its consequences. Using multiple viewpoints of the “multy-layer safety”: flood warning, flood prevention, special planning and disaster management, this book gives lessons from the storm for the Netherlands. Please note: We have used all available public sources up to the beginning of August 2010. The official facts about the storm have been assembled in three French public enquiries, by each house of parliament and by the French ministry of Ecology, Energy Transport and Development MEEDEM. Our purpose is to give lessons for the Netherlands and not to give a perfect list of facts about the storm. The Dutch, French and English versions differ slightly. Some background information has been added in each language.

Catalogus van waterkeringen die tijdelijk geplaatst kunnen worden, al dan niet als noodkeringen

The coastal areas of Vietnam are repeatedly hit by devastating storms and typhoons. Protective sea dikes are overtopped or breached frequently, with the resulting flooding causing damage to agriculture land, loss of life and crops, and destruction of infrastructure. In the coastal area of the five northern provinces of the Red River Delta, 361 kilometres dikes will be upgraded, assisted by the World Food Program, project number 5325. This project is the follow-up of the WFP project number 4617, which was focused on 7 provinces along the Central Coast. As a result of the strong similarity in physical nature between the Netherlands and Viet Nam on water related issues, the Ministry of Agriculture and Rural Development of the Socialist Republic of Vietnam has requested to the Ministry of Transport, Public Works and Water Management of the Netherlands for technical assistance on flood control issues. As a first step the Dutch Ministry has sent in November 1995 two representatives, mr. Anne van Urk and mr. Ale van der Hoek, to discuss many flood control and water management issues in Viet Nam, on which cooperation can take place. One of the issues with the highest priority was to get a second opinion on the sea dike designs as to be used in the WFP program. So as a second step in the program a mission visited Vietnam, from 26 March to 12 April 1996, in order to evaluate the existing designs and execution options for the five coastal provinces of the Red River Delta.

Flooding is a major problem for many people in the United Kingdom, posing a risk to health, safety and wellbeing, and resulting in widespread damage to property. The scale of the problem can be gauged from the following quotation (OST, 2004): Nearly 2 million properties in floodplains along rivers, estuaries and coasts in the UK are potentially at risk of flooding. 80,000 properties are at risk in towns and cities from flooding caused by heavy downpours that overwhelm urban drains – so-called ‘intra-urban’ flooding. In England and Wales alone, over 4 million people and properties valued at over £200 billion are at risk. In the autumn 2000 floods, 10 000 properties were flooded at more than 700 locations at a cost in the order of £1.0 billion. With the effects of climate change and increased societal pressures on the country’s infrastructure and services, the risks of flooding are predicted to increase considerably. Flood damage to properties can range from minor effects on walls, floors, basements and services to serious structural damage to buildings. However, practical steps can be taken to reduce the cost of flood damage and to speed up recovery times should the flood return. This guide sets out requirements for the repair of buildings following flooding and includes: * a description of the causes of flooding and the impact that floods can have on buildings * making safe, decontamination and drying activities that must be undertaken immediately after the floodwaters have receded, including recommendations on appropriate health and safety risk assessments * conducting post-flood surveys and future flood risk assessments * standards of repair for buildings following flooding. The repair of buildings has to be appropriate to both the extent of damage and the risk of future flood. As the risk increases the proposed standard of repair is more rigorous, effectively increasing the resilience or resistance of the building to flooding. Three levels of standards of repair are included in the guidance. For each standard of repair, guidance is provided for external walls, internal walls, floors, fenestration, basements, services and fittings. The guide contains illustrations of damage, surveys, drying and decontamination, and repair work to buildings. Appendices include guidance to homeowners, technical information, key organisations that can advise on flooding and information on the provision of insurance. The guidance is aimed primarily at building professionals and insurers experienced in flood damage and repair. It may also be used by general builders, surveyors and building-owners, including householders, for advice in commissioning repair work.

Evaluation on mitigation of natural disasters, mainly floods, in Central Vietnam, results of the findings of the mission, policy planning, disaster response, sustainability, donor response, prioritized list of mitigation projects, empowerment of communities that live with floods,

A chain is never stronger than its weakest link. This insight is the basis for the calculation method to determine the f lood probabilities of dike ring areas in the Netherlands. The TAW can already formulate first recommendations on research and policy making. This does not imply that the research on 'Flood risks: a study on probabilities and consequences' is already finalised. This study concentrates on probabilities and consequences. Developing a method to estimate consequences of f looding is the next step of the TAW. Then it also will be possible to estimate the costs and benefits of the alternative measures

This document outlines the Cabinet's position on water management policy in the 21st century. Immediately fuelling this is my concern about increasing water levels in the rivers, flooding, and the accelerated rise in sea level. In a country like the Netherlands, the geography of which is dominated by the sea and the mouths of four great rivers, water and natural space are inextricably bound to one another. For centuries, spatial planning in the low-lying Netherlands has been a matter of separating and maintaining the separation between land and water. And we have benefited from this, considering the fact that two-thirds of the gross national product (around NLG 400 billion annually) is generated domestically. But changes are brewing. Climatic changes are increasing the likelihood of flooding and water-related problems. In addition, population density continues to grow, as does the potential of the economy and, consequently, the vulnerability of the economy and society to disaster. Two undesirable developments that, in terms of safety, potentiate one another - a growing risk with even larger consequences. As such, the safety risk is growing at an accelerated pace (safety risk = chance multiplied by consequence). In 1999, together with the president of the Association of Water Boards (UvW), I requested an independent Committee to determine whether current water management policy is sufficiently equipped for the future - an effort that came none too soon. Across Europe and abroad, we have witnessed the consequences of superfluous water. The events in Switzerland, Italy and the UK have shown us the importance of looking ahead. The Committee concluded that the current water management system was not capable of responding to future developments. In order to keep the Netherlands safe, liveable and attractive in terms of water for inhabitants and investors for the century to come, a change in water management policy and in the way we approach water is required. This change involves the idea that the Netherlands will have to make more frequent concessions. We will have to relinquish space to water, and not win space from it, in order to curb the growing risk of disaster due to flooding, limit water-related problems and be able to store water for expected periods of drought. By this, I do not mean space in terms of the height of ever taller dykes or depth through continued channel dredging, but space in the sense of breadth. This will cost space, but in return we will increase safety and limit waterrelated problems. Safety is an interest that must play a different role in spatial planning. Only by relinquishing space can we set things right and if this is not done in a timely manner, water will sooner or later reclaim the space in its own, perhaps even dramatic, manner. My argument to innovate water management policy appears to be widely accepted, but more is required. It demands creativity, energy, time and money. Protecting the Netherlands from flooding will require repeated investments over a long period of time.