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Coastal Storms and Flooding: Regulatory Framework and Science-Policy Interactions

1.1. Introduction

Coastal storms and flooding are areas of increasing concern, owing to growing urbanization and the related increased vulnerability to extreme climate events [IPC 14]. The increasing exposition of populations to such hazards leads to challenges linked to the development and implementation of regulations and management practices which take into account the adaptation to climate change. Actions related to improved risk prevention and reduction of climate-related hazards are embedded nowadays into international, European Union and national regulations and related management frameworks. In the case of coastal zones, however, although the prevention of hydrometeorological hazards is recognized as a priority at national level in many countries, the precise definition of these risks and hence their relations with the existing policy framework remains unclear [LAR 15]. The identification of coastal hazards (mainly storms and floods) concerns several domains other than the environment; in particular, urbanism, forestry, the insurance sector, tourism and civil protection, which are addressed by different types of regulations and codes of practice. This fragmentation is reflected from the EU to the national/regional levels. In addition, coastal risks are not subject to specific regulations despite being often mentioned, e.g. in research projects (see section 1.5) and texts related to territorial management plans.

Natural hazards in coastal zones can be separated into different types of risks [CAN 14], either of marine origin, e.g. submersion/flooding, storms, erosion, tsunamis, waves due to tornados, or of geological nature, e.g. land subsidence, earthquakes, landslides. In the context of this book, the focus will essentially be on coastal storms and flooding related to marine submersions, which may result from a combination of different phenomena such as wind, waves, high tide coefficients, low atmospheric pressures (leading to an elevation of the marine level) and abundant rainfalls. Marine submersions are considered as cumulative phenomena leading to either (or both) rapid or progressive flooding. The case of the Xynthia storm, which occurred along the West coast of France in February 2010, deals with both cases, i.e. a flash flood in the North (La Faute-sur-Mer) and progressive flooding in the South (Oleron island, Fouras, etc.). In each case, such submersion may lead to displacement of populations, significant modifications of land occupations and uses, losses of land as well as various environmental perturbations in wetlands and lagoons with modifications of the local ecosystems (e.g. salinization of freshwater resources and disappearance of beaches). Socio-economic and environmental impacts related to natural hazards in coastal zones, and notably coastal flooding, are therefore highly significant and subject to many controversial debates and studies. In reference to Xynthia, consequences of this storm generated many enquiries, scientific studies, historical research, etc., which all pointed out limitations of knowledge about coastal risks and their social nature. Adversely, policymakers and politicians did not express themselves very much at all, despite media controversies flourishing in relation to inadequacies of the regulatory framework. Chapter 3 refers to this specific case which is also described in details (in French) in the literature [GAR 13, LAR 15]. The present chapter provides a general background about the existing regulatory and EU-funded scientific framework and discusses difficulties in establishing interactions among the scientific and policy-making communities.

According to IPCC [BAT 08], observational records and climate projections provide abundant evidence that observed warming over several decades has been linked to changes in the large-scale hydrological cycle (e.g. effects on atmospheric water vapor content and changes of precipitation patterns with consequences on extreme floods and droughts). The consequences of climate change, in particular the increased frequency and severity of extreme hydrometeorological events, may alter the reliability of current water management systems. While quantitative projections of changes in precipitation, river flows and water levels at the river-basin scale remain uncertain, it is very likely that hydro(meteo)logical characteristics will change in the future. These considerations lead to the development of a complex policy framework which plans adaptation and mitigation options to tackle impacts of global warming on water resources and risks to society and assets. These options are closely linked to a range of policies. This chapter gives an outline of some policies relevant to hydrometeorological events, with no pretention of exhaustiveness. Some considerations have been adapted from previous publications [QUE 11a, QUE 11b, QUE 14].

1.2. Natural hazards and risks in coastal zones: needs to build-up a "culture of risks"

1.2.1. Introduction

Coastal zones were unoccupied for centuries as they were considered as dangerous areas by populations. This has changed only recently with the establishment of populations along coastlines, increasing their exposure to natural hazards (e.g. flash floods, seismic risks associated with tsunamis, marine submersions and erosion). Nowadays the littoral zone is very much in-demand and is confronted with a growing demography. The United Nations even estimates that, at the 2020 horizon, around 80% of the world population will live in a territorial stretch less than 100 km from the sea. As a result, natural hazards in coastal areas will increasingly threaten human societies, their assets and activities. These threats will be exacerbated by climate change which has an influence not only the sea-level rise but also on rainfall regimes and storm severity [LAR 15]. In less than 20 years, the awareness about climate-related risks has led to a huge development of research activities (see section 1.5).

A natural risk is generated by the conjunction of a threatening phenomenon which is identified as a hazard, and related human challenges characterized by their vulnerability to this hazard. In a way, human societies' awareness of natural hazards has certainly played a major role in the development of environmental policies, originally aimed toward the prevention of disasters rather than the protection of the environment itself. This policy sector has hence led to establishing founding principles of what may be referred to as a "culture of risks", which is being developed at policy level as well as in the collective consciousness [LAR 15].

In parallel, coastal zones present the paticularity of gathering several environmental compartments, which generates legal discussions that are reflected in specific environmental policies, with the risk of fragmentation. Considering the diversity of natural hazards, their intensity and potential impacts which may vary from region to region, the regulatory framework and its implementation may have different socio-economic and environmental dimensions, and the specific regulations have to be properly coordinated in order to manage the risks efficiently.

1.2.2. Contribution of environmental policy to the development of a "culture of risks"

According to Michelot in [LAR 15], the "culture of risk" can be defined as "the ensemble of perceptions and behaviours adopted by a society facing risks". It is associated with the society's memory about risks, i.e. a system of maintenance of the legacy of knowledge from the past and its consideration for reduction of today's vulnerability. This presents the idea of highlighting the need to better understand hazards and their impacts, and of developing the information, the education and the memory of risks. In a sense, developing a "culture of risks" is closely related to a democratic decision-making process on both an individual and collective scale. Every citizen should have the possibility to freely access information about the risks to which he/she is exposed as well as objective information on what is done to protect his/her security. The Civil Society, enterprises and representatives of national authorities should also be in the position to respond to citizen's expectations regarding their security.

This awareness carries greater significant nowadays with the increased frequency of natural hazards, some of them leading to disasters. This risk awareness is, however, not new. In the marine sector, the risks for navigation were well identified and related to dangers that were not linked to human actions [EWA 86]. Until the 19th Century, the notion of risk was linked to natural events. This changed with the industrial revolution, which led us to consider human activities as generating risks as well which had to be understood, managed and even anticipated [LAR 15].

Before speaking about environmental policies and their links to the "culture of risks" for coastal areas, it is useful to recall the role of policies in the establishment of this culture of risks. In a sense, we might argue that policies should include risk components and related objectives. This is the principle followed more largely by the DPSIR approach (Driver-Pressure-State-Impact-Response), which includes the notion of risks and responsibilities regarding the "responses" to address them. Environmental policies have the peculiarity of repositioning the relationship with risks in...