Modélisation de l'évacuation, des décès et des blessés lors des inondations de 1953 à Canvey Island dans l'estuaire de la Tamise.

Canvey Island est une île située dans l'estuaire de la Tamise au sud-est de l'Angleterre. Le terrain s’élève en moyenne à un mètre au dessus du niveau moyen de la marée haute. Un réseau de digues protège Canvey Island contre les inondations marines. En 1953, l’île a été inondée par « La Grande Inondation de la Mer du Nord ». Cinquante-huit personnes sont décédées. Un modèle hydraulique a été élaboré pour simuler la submersion de l’île en 1953. Un second modèle a été proposé pour estimer le nombre de morts. Ce modèle s’appelle « Life Safety Model » (Modèle de Sécurité de la Vie). Le « Life Safety Model » repose sur une modélisation des personnes, des véhicules et des bâtiments. Le but des recherches était d’améliorer la compréhension de l’événement de 1953 et d’analyser les conséquences des ruptures des digues, notamment sur le taux de mortalité et de blessé. Ces travaux ont montré qu’une modélisation et une simulation « multi-agents » fournissent des méthodes scientifiquement robustes pour déterminer le nombre de personnes blessées et décédées lors d’une grande inondation

Reducing the uncertainty in indirect estimates of extreme flash flood discharges

Direct current meter measurements are rarely available for extreme flash floods. Corresponding discharges are generally estimated using so-called “indirect” techniques such as the slope – area method. These methods are based on empirical hydraulic formulae that typically use Manning’s equation, and have been calibrated and also widely tested for flow conditions that differ significantly from those encountered during flash floods. Recent work conducted in Europe, as part of the HYDRATE research project and other studies, has shown that the use of these formulae and their associated tabulated roughness values available in current guidance documents, without further verification, can lead to over-estimates of peak discharges in the case of flash floods. After having discussed the limitations of indirect methods based on Manning’s formula, the paper illustrates how the uncertainty in indirect discharge estimates can be reduced through the analysis of various types of data that can be collected during post-event surveys and through consistency checks. Based on a review of current literature and on recent flash flood studies, this paper proposes simple guidelines to assist practitioners in estimating extreme discharges during post-event surveys

Tools to improve the production of emergency plans for floods – are they being used by the people that need them?

Major floods in Europe over the past decade have illustrated the impact of these events not only on the economy, but also on the health and well-being, as well as the safety of communities. In the past five years emergency plans, some of which focus specifically on flooding, have started to be developed in both England and Wales, and France. At present, tools, such as checklists, guidance and specialised software appear to be used rarely to improve the effectiveness of these plans. Research was undertaken with flood managers in the two countries who are responsible for providing technical input to plans. The objective was to establish why tools, methods or guidance that can usefully contribute to improving emergency plans for floods are often not being used. The research showed that many flood managers are often not aware of the tools that are available to assist them in formulating emergency plans for floods. It was concluded that there is a need for guidance on: what tools are available; what data they require; and how the tools can be implemented to provide information that can be used to improve emergency planning for floods

A comparison of the causes, effects and aftermaths of the coastal flooding of England in 1953 and France in 2010

This paper provides a comparison of the causes, effects and aftermaths of the coastal flooding that occurred on the east coast of England in 1953 and the west coast of France in 2010 that resulted in 307 and 47 deaths respectively. The causes of both events are strikingly similar. Both were caused by a combination of high tides, low atmospheric pressure, high winds and the failure of poorly maintained flood defences. In both cases the number of deaths was related to the vulnerability of the buildings and people. Buildings in the flood zones were often single storey bungalows and the people who died were mostly over 80 years of age. Both tragedies were national disasters. The 1953 flood in England acted as a catalyst for an acceleration in flood risk management policy and practice. It resulted in: the development of a Storm Tide Warning System for the east coast of England; the setting of new design standards for coastal flood defences; increased investment in improving coastal defences; and a substantial new research effort into coastal processes, protection and forecasting. In France there has also been an episodic shift in flood risk management policy with the focus falling on: control of urban developments in areas at risk of flooding; improved coastal forecasting and warning; strengthening of flood defences; and developing a “culture of risk awareness”. This paper outlines the lessons that can be learnt from the two events and provides recommendations concerning how future loss of life as a result of coastal flooding can be reduced

Evacuation and loss of life modelling to enhance emergency response

Recent major flood events from around the world have highlighted the importance of an effective emergency response in minimising loss of life and optimising the resources available. This paper describes the development of a dynamic, agent based, Life Safety Model (LSM) to estimate the flood risk to people in terms of loss of life and injuries, evacuation times and how improvements in emergency planning can reduce both of these. The LSM is the only tool that is currently available that allows for a dynamic interaction between people, vehicles, buildings and the floodwave. The model takes an approach based on the latest available physical equations rather than empirically deduced mortality rates and evacuation times. The model includes traffic and pedestrian models and also the ability to simulate the effectiveness of the dissemination of flood warnings on people’s behaviour. This paper will give a general overview of the capabilities and features of the LSM, and will illustrate this with a range of applications. These will include: a dam failure in France, a major coastal surge in the Thames Estuary in 1953 and Pacific tsunami impacts for western Canada

D-MOSS: An integrated dengue early warning system in Vietnam driven by Earth Observations

Dengue is the fastest-growing mosquito-borne viral infection in the world today. It is present in over 150 countries, meaning that around 40 percent of the world’s population now live in countries where dengue is a daily risk. It has been estimated that annually dengue affects 390 million people and has a global cost of almost US$9 billion per year. Since 2000, there has been an increase of over 100% in the number of cases of dengue fever in Vietnam, with approximately 185,000 cases occurring in 2017 alone. In Vietnam, there is currently no system for forecasting future dengue outbreaks. D-MOSS is the first fully integrated dengue fever forecasting system incorporating Earth Observation data and seasonal climate forecasts to issue warnings on a routine basis. D-MOSS integrates multiple stressors such as water availability, land-cover, precipitation and temperature with data on past dengue fever incidents. This information is used to develop statistical models of disease incidence, that can then be used to forecast dengue outbreaks based on seasonal weather and hydrological forecasts as well as other factors. An overview of the D-MOSS web page and the forecasts it produces are shown in the accompanying figure. D-MOSS takes the form of a web-based platform. The system’s architecture is based on open and non-proprietary software, where possible, and on flexible deployment into platforms including cloud-based virtual storage and application processing. D-MOSS is currently being piloted in Vietnam. When the system becomes fully operational it should assist the Vietnamese Ministry of Health, to meet its goal of actively to forecast, detect early and prevent the occurrence of epidemics, especially major ones. The project is funded by the UK Space Agency’s International Partnership Programme and we have been recently awarded with an extension to our grant to implement D-MOSS to another six countries in South East Asia

D-MOSS: Dengue forecasting MOdel Satellite-based System

D-MOSS, Dengue forecasting MOdel Satellite-based System, is a dengue fever early warning system for Vietnam being developed by a project funded by the UK Space Agency’s International Partnerships Programme. The D-MOSS project is developing a suite of innovative tools that will allow public health authorities to identify areas of high risk for disease epidemics before an outbreak occurs, in order to target resources to reduce spreading of epidemics and improve disease control. Since 2000, there has been an increase of over 100% in the number of cases of dengue fever in Vietnam, with 185,000 cases occurring in 2017 alone, and there is currently no system for forecasting future dengue outbreaks. The D-MOSS early warning platform includes a water availability component. Water availability directly impacts dengue epidemics due to the provision of mosquito breeding sites. These dynamics are often non-linear; too much rainfall can fill outdoor containers, while too little can lead to people storing water in open containers within their homes. Both increase the population of Aedes aegypti mosquitoes and in turn the risk of dengue outbreaks. However, water availability or water resource management is rarely accounted for in dengue prediction models. The system generates monthly water stress assessments and uses them as inputs to a component of the dengue early warning system which also improves the skill of the system’s predictions. In addition, these forecasts of water stress will help to improve Vietnam’s water management. Vietnam’s Sustainable Development Strategy for 2011-2020 identifies one of the major challenges facing Vietnam as the issue of transboundary water management, because 63% of the surface water comes from upstream countries. The D-MOSS project is developing a forecasting system in which Earth Observation datasets are combined with weather forecasts and a hydrological model to predict the likelihood of future dengue epidemics up to eight months in advance. The system is calibrated against historical data. The water availability forecasts are fed into statistical forecasting models of disease incidence. This dengue early warning system model integrates the water stress forecast with a range of other covariates important for dengue transmission. The D-MOSS project is within the first year of its three-year term and is currently focused on platform and model development, while gathering the key input data and engaging with the Vietnamese government to ensure that all components are fit for purpose. The portrayal system is designed to communicate the dengue and water availability forecasts to the Vietnamese Ministries of Health and Natural Resources and Environment, respectively. A user interface will also incorporate supporting information on recommended actions, provided by the decision makers and based on the forecasts and associated uncertainty

Engaging stakeholders in research to address water-energy-food (WEF) nexus challenges

The water–energy–food (WEF) nexus has become a popular, and potentially powerful, frame through which to analyse interactions and interdependencies between these three systems. Though the case for transdisciplinary research in this space has been made, the extent of stakeholder engagement in research remains limited with stakeholders most commonly incorporated in research as end-users. Yet, stakeholders interact with nexus issues in a variety of ways, consequently there is much that collaboration might offer to develop nexus research and enhance its application. This paper outlines four aspects of nexus research and considers the value and potential challenges for transdisciplinary research in each. We focus on assessing and visualising nexus systems; understanding governance and capacity building; the importance of scale; and the implications of future change. The paper then proceeds to describe a novel mixed-method study that deeply integrates stakeholder knowledge with insights from multiple disciplines. We argue that mixed-method research designs—in this case orientated around a number of cases studies—are best suited to understanding and addressing real-world nexus challenges, with their inevitable complex, non-linear system characteristics. Moreover, integrating multiple forms of knowledge in the manner described in this paper enables research to assess the potential for, and processes of, scaling-up innovations in the nexus space, to contribute insights to policy and decision making

An assessment of flood emergency plans in England and Wales, France and the Netherlands

This paper details research carried out in England and Wales, France and the Netherlands on the evaluation of emergency plans for floods. To assess the flood emergency plans 22 metrics were developed. These metrics covered a range of issues from the aims and objectives of the plan to training and exercises. A number of emergency plans in each of the three countries were reviewed using these metrics and online surveys of emergency planners were carried out. The objectives of the surveys were to establish what information emergency planners believe is useful to incorporate in emergency plans and at what level of detail. The developed metrics and survey of end users provided a basis to compare emergency plans. The effectiveness of an emergency plan is difficult to measure and end users often stated that this can only be assessed accurately after a plan has been used. Many emergency planners indicated that a well defined description of the roles, responsibilities and communication is essential for a plan to be effective. These aspects tended to be well covered in the evaluated plans. However, other more technical aspects such as accessibility of roads, evacuation, depiction of the flood hazard and impacts of floods on critical infrastructure can be considerably improved. The main challenge for emergency planners is to avoid filling plans with generic text and to provide an appropriate level of specific detail in the plan whilst ensuring the “usability” of the plan

A review of the consideration of climate change in the planning of hydropower schemes in sub-Saharan Africa

There are over 580 million people in sub-Saharan Africa without access to electricity. The region has significant untapped hydropower potential that could contribute to improving domestic access to electricity and countries’ economic development, as well as helping to meet the Sustainable Development Goals. Changes in climate affect hydropower generation through alterations to river flow regimes. Hence it is the energy source most likely to be affected by climate change because the amount of electricity generated is directly related to water quantity and its timing. However, climate change impacts are rarely explicitly considered when planning new hydropower projects in the region. This may be because current fluvial discharge series in sub-Saharan Africa display high levels of natural variability and it is only after the 2050s that climate-driven changes in river flows emerge from these. Planning horizons of hydropower projects are usually around 30 years, so the natural variability of the existing hydrological regime is within the variability of climate change projections and hence it is unlikely to be considered. Another reason is that over the past 15 years China has become a significant financer of infrastructure in the region. China only meets the environmental regulations of the country in which the hydropower scheme is being constructed. Most sub-Saharan African countries do not have regulations that include climate change in the planning of such projects. This paper concludes by suggesting a framework via which climate change can be incorporated in future hydropower schemes at a river basin scale