Spatiotemporal characteristics of flood protection level

Abstract:

Flooding is the most frequent natural hazard and its global impacts will be rising associated with climate change and socioeconomic growth. So, the understanding of the physical and spatial-temporal patterns of risk drivers (exposure, damage, and flood protection level) are required to conduct effective adaptation and reduce the negative impacts of flooding. Although the understanding of exposure and damage has greatly improved using a combination of numerical model simulation and spatiotemporal distributions of population and asset, that of flood protection level is still lacking in particular spatial patterns. Previous research clarifies its temporal variation and relationship with per-capita income, however they do not consider its spatial variation. Flood protection level was associated with geographical characteristics (e.g., soil type and tectonic zone etc). This study tried to estimate spatiotemporal of flood protection level at country level and discuss about relationship between its spatial patterns and geographical characteristics. Mortality rate (percentage of fatalities in modeled exposed population) and loss rate (percentage of losses in modeled exposed GDP) to fluvial river flooding across the world suggested by Jongmann et al. (2015) were estimated from modeled flood exposure and damage statistics taken from the International Emergency Disasters Database. The result indicated that mortality rate reduced across the world from 1990 to 2005. The degree of its reduction decreased with increasing per-capita income level. On the other hand, loss rate at high income and middle low income levels reduced, while that at middle high income and low income levels drastically increased between 1995 and 2000 due to growth economic and occurrence of serious fluvial river flooding. Spatial distribution of mortality and loss rates were high in East Asia, the western part of South America, and the eastern part of Europe. These regions seem to be corresponded to the Pacific tectonic region. An in-depth understanding of flood protection levels were important not only per-capita income level, but also the geographical characteristics. These results were useful for the effective adaptation strategy.