Efficient pan-European river flood hazard modelling through a combination of statistical and physical models

Abstract

Abstract. Flood hazard is currently being researched on continental and global scales, using models of increasing complexity. In this paper we investigate a different, simplified approach, which combines statistical and physical models in place of conventional rainfall-run-off models to carry out flood mapping for Europe. A Bayesian-network-based model built in a previous study is employed to generate returnperiod flow rates in European rivers with a catchment area larger than 100 km 2 . The simulations are performed using a one-dimensional steady-state hydraulic model and the results are post-processed using Geographical Information System (GIS) software in order to derive flood zones. This approach is validated by comparison with Joint Research Centre's (JRC) pan-European map and five local flood studies from different countries. Overall, the two approaches show a similar performance in recreating flood zones of local maps. The simplified approach achieved a similar level of accuracy, while substantially reducing the computational time. The paper also presents the aggregated results on the flood hazard in Europe, including future projections. We find relatively small changes in flood hazard, i.e. an increase of flood zones area by 2-4 % by the end of the century compared to the historical scenario. However, when current flood protection standards are taken into account, the flood-prone area increases substantially in the future (28-38 % for a 100-year return period). This is because in many parts of Europe river discharge with the same return period is projected to increase in the future, thus making the protection standards insufficient.

Flood Hazard Mapping Using the Flood and Flash-Flood Potential Index in the Buzău River Catchment, Romania

“…European rivers are specifically analyzed in accordance with the European Flood Directive 2007/60 and the Directive 2008/94/EC of the European Parliament and of the Council, published in the Official Journal of the European Union, whilst statistical, hydraulic and GIS techniques are used for hazard and flood mapping [4][5][6] Adaptation and mitigation have generally been treated as two separate issues, both in public politics and in practice, in which mitigation is seen as the attenuation of the cause, and studies of adaption look into dealing with the consequences of climate change [7]. Studies on the impact of climate change on flood risk are mostly conducted at the river basin or regional scale [8,9].…”

Stochastic generation of spatially coherent river discharge peaks for continental event-based flood risk assessment

“…In particular, the (re)insurance industry wants to know the chance of a widespread portfolio of assets being affected in a short time window (Jongman et al, 2014). With the increase in computational power, continental FRAs have recently become feasible (Ward et al, 2013;Alfieri et al, 2014;Dottori et al, 2016;Vousdoukas, 2016;Winsemius et al, 2016;Paprotny et al, 2017;Serinaldi and Kilsby, 2017). Vorogushyn et al (2018) call for new methods for large FRAs to enable the capturing of system interactions and feedbacks.…”

Low cost, multiscale and multi-sensor application for flooded area mapping

“…Flood mapping and damage assessment is also an important issue for European Communities authorities that support projects, such as the Copernicus Emergency Management Service mapping (EMSR) and the European Flood Awareness System (EFAS), which manage the activation procedure to acquire satellite data over the areas affected by a natural hazard. De Moel et al (2009) and Paprotny et al (2017) described further details about different experiences of flood mapping in Europe.…”