Coastal flood: a composite method for past events characterisation providing insights in past, present and future hazards—joining historical, statistical and modelling approaches

Abstract

The characterisation of past coastal flood events is crucial for risk prevention. However, it is limited by the partial nature of historical information on flood events and the lack or limited quality of past hydro-meteorological data. In addition coastal flood processes are complex, driven by many hydrometeorological processes, making mechanisms and probability analysis challenging. Here, we tackle these issues by joining historical, statistical and modelling approaches. We focus on a macrotidal site (Gâvres, France) subject to overtopping and investigate the 1900-2010 period. We build a continuous hydro-meteorological database and a damage event database using archives, newspapers, maps and aerial photographies. Using together these historic information, hindcasts and hydrodynamic models, we identify 9 flood events, among which 5 are significant flood

The Effect of Stochasticity of Waves on Coastal Flood and Its Variations with Sea-level Rise

“…The present work aims at investigating the influence of the stochastic character of waves on coastal floods for different flood regimes. This work is done on the real site of Gâvres (France), which is subject to flood induced by overtopping and has faced several floods since 1900 [2]. We show that the stochasticity of waves is far from being negligible, especially for floods resulting mainly from wave overtopping, and, depending on the flood regime, this effect is comparable to that of sea-level rise scenarios of few tens centimeters, for the past reference events we consider in this work.…”

“…After Ref. [2], this site has been subject to 9 flood events (including 5 major floods) between 1900 and 2010. The waves arriving at the coast are affected by the presence of an offshore island (Groix) located at the West of the study site (Figure 1a), such that the offshore wave conditions between the site and Groix are strongly non-uniform.…”

“…Coastal floods are driven by many hydro-meteorological forcing conditions, among which are mean sea levels, tides, atmospheric storm surges, and waves. Coastal flood modeling made significant progress these last years, especially in the estimation of floods induced by wave overtopping [1,2]. A widely used approach is to first propagate the water levels and waves close to the coast using most of the time shallow-water and wave spectrum models, respectively, and then to model the flood, i.e., the water height and current inland, and deduce flood information (e.g., water height map, hazard map, flooded area, seawater volume).…”

Hydro- and Morphodynamic Impacts of Sea Level Rise: The Minho Estuary Case Study

“…With these tools it is possible to anticipate potential problems and design adequate mitigation solutions. Since long term forecast imply a huge uncertainty for horizons of 50-100 years [36], it is advised to implement operational models that assimilate the historical behavior and continuously produce new forecasts. The costs for the study and for implementing measures to adapt and increase the resilience of sensible areas against these problems will be less than the cost of repairing the damages after the occurrence of extreme events.…”

Gaussian process metamodeling of functional-input code for coastal flood hazard assessment

“…All registers are located offshore of the study site over the period 1900-2016. The dataset is constituted by the concatenation of hindcasts of different sources (see Appendix A), with bias corrections between the hindcasts through a quantilequantile correction method (for more details, see [30]). The various hindcasts have different time steps.…”