Assessing climate change impacts on flooding risks in the Belgian coastal zone

Within the scope of the Belgian project CLIMAR an attempt is made to develop an evaluation framework for adaptation scenario’s as a response to the climate change induced impacts in the North Sea area. Primary effects are direct consequences of climate change such as sea level rise, erosion, changes in temperature and precipitation and increased storminess. Secondary impacts are direct and indirect results of the primary effects on different sectors. A first phase of the project consists of identifying and scoping the secondary impacts on ecological and social-economic activities. In this paper results will be presented regarding the secondary impacts of flooding only.Climate change induced primary effects such as sea level rise and increased storminess lead to higher risks of flooding of low-lying coastal areas. One of the most significant social secondary effects is the number of people at risk due to flooding. An important economical effect of climate change is the amount of damage costs. Besides direct damages there will also be indirect economic results such as temporary suspension of production and loss of jobs. Other ecological effects of increased flooding risks are the loss of beach and dune area, as well as associated specific habitats such as wetlands. Indirectly this leads to loss of biodiversity.The magnitude of the most significant secondary effects is quantified by carrying out risk calculations. For each of the sets of the changing physical parameters a related storm scenario is statistically determined. In a first approach, the flooding risks during an extreme storm under present climate conditions and sea level rise are estimated. By means of a set of numerical models the areas susceptible to flooding in the Belgian coastal plain are identified. The resulting flooding risk maps are then used to estimate the scope of the secondary impacts

CLIMAR: evaluation of climate change impacts and adaptation responses for marine activities. Subdocument coastal flooding

Within the project CLIMAR an attempt is made to develop an evaluation framework for adaptation responses toclimate change induced impacts within the North Sea environment. The identification and quantification of all thepossible secondary impacts of climate change is handled on a sectoral level. The different case-studiesinvestigated in the framework of the research are fishery, tourism, sand and gravel extraction, the port ofZeebrugge and flood risks. This document gives an overview of all the different types of land occupation andinfrastructure within the coastal zone that might be subject to flood risks as a consequence of primary climatechange impacts

Assessing the storm vulnerability of the Belgian coastline

Climate change is likely to induce increased sea level and storm frequency. As such, assessing the strength of the Belgian coastal defence infrastructure against natural hazards is of primordial importance to reduce inundation consequences to properties and nature. This study presents an integrated methodology to estimate damage risks from a hypothetical storm with a surge level of +8m TAW and a duration of 45 hours along the entire coastline. After translation of deep water hydrometeorological conditions to the nearshore, several failure modes of the defence infrastructure are modelled: beach and dune erasion, collapse of dikes due to wave impact and overtopping, and subsequent breach forming and flooding of the low-lying coastal plain. Attention was paid to the various model uncertainties. Damage of infrastructure, properties and human casualties are calculated using a raster-based GIS model. Multiplication of the results with a rate factor based on prognoses of the evolution of socio-economic parameters allows projection of the results to 2050. All this, in combination with a social cost benefit analysis, will provide a tool for supporting coastal zone management in Belgium in a quantitative way

Coastal flooding risk calculations for the Belgian coast

Coastal flooding risk calculations are carried out for the entire Belgian coastal zone to support the management ofthe coastal defence system. The floodprone low-lying coastal area has an average width of 20 km and is locatedon average 2 m below the surge level of an annual storm. The natural sea defences are sandy beaches anddunes, which have been strengthened by revetments in the coastal towns. The Belgian standard of coastalprotection is to be safe against a surge level with a return period of 1000 years, but at present it is investigated if and how this standard could be redefined based on risk analysis

SAFECoast: Comparison between different flood risk methodologies. Action 3B report - SAFECOAST Interreg IIIb North Sea Project

The Interreg IIIB project SAFECoast considers the question “How to manage our North Sea coasts in 2050?’ and focuses on the consequences of climate change and spatial developments with respect to safety from coastal flooding. Therefore, a team of coastal managers from the Netherlands, Germany, Belgium, Denmark and the UK are continuing their cooperation in SAFECoast which aims to build on each other’s experiences in, and understanding of coastal risk management. Flanders Hydraulics Research (FHR, located in Borgerhout, Belgium) has proposed a flood risk methodology in the past which makes it possible to compare different areas and different situations with a view to damage and risk calculations. In the past years, the methodology has been extended and improved, and meanwhile it is used in several studies in Flanders. This report is the contribution of Flanders Hydraulics Research to the SAFECoast project (action 3b). The goal is to compare basic parameters of the existing coastal risk methodologies and make an inventory of the strong and weak points of the different approaches. It is neither possible nor desirable to make a ranking of them. Because of data availability and case specific parameters and constraints, each methodology generally fits the best for the area they are made for. However we want to learn from them and incorporate good ideas to improve the existing methodologies. To improve coastal risk methodology means to make its results less uncertain, or more complete. In this study all the different sources of uncertainty are analysed and compared so it becomes possible to identify the weak links in the calculation chain