Causes, impacts and patterns of disastrous river floods

Abstract

River floods caused about 7 million fatalities in the twentieth century 1 , and their direct global average annual loss (AAL) is estimated at US$ 104 billion (2015Exposure to floods is expected to grow by a factor of three by 2050 owing to increases in population and economic assets in flood-prone areas 3 . Depending on the socio-economic scenario, human losses from flooding are projected to rise by 70-83% and direct flood damage by 160-240% relative to 1976-2005, with a temperature increase of 1.5 °C (ref. 4 ). Understanding river flooding and its associated impacts are critical to effective risk reduction.River floods occur when a river overtops its banks and inundates adjacent areas. The expected impact floods have on society and the environment, often termed flood risk, results from the superposition of three components and the associated processes, which tend to be interlinked [5][6][7] , including over large distances 8 . These components are: hazards -the processes leading to high river flood levels; exposure -the elements at risk, such as population or infrastructure; and vulnerabilitythe susceptibility of the elements at risk when they are affected by a flood 2 . These components are, in turn, the compound effects of multiple processes (fig. 1).

PHEV! The PHysically-based Extreme Value distribution of river flows

“…This initial data screening resulted into 161 gauges (483 catchment-season case studies) retained for analysis, whose geographical locations are shown in figure 1(G). The Mann-Kendall test applied to seasonal maxima identified significant (p < 0.01) trends in only a marginal fraction (3%) of the case studies, confirming the absence of flood trends for this region highlighted by [46].…”

On the links between sub-seasonal clustering of extreme precipitation and high discharge in Switzerland and Europe

“…We focused here on the link between precipitation clustering and high discharge. Still, whether high discharge translates into a flood, particularly a disastrous one, depends on many other factors, like antecedent catchment wetness, the presence of infrastructure and its management, or the timing of precipitation across the catchment (Merz et al, 2021). These factors can also interact across various spatial and temporal scales, depending on the flood event.…”

Spatial and temporal distribution of estimated surface runoff caused by land use/land cover changes in the upstream Citarum watershed, West Java, Indonesia

“…Flood is the most destructive natural hazard in the world. It adversely impacts the environment and human life, especially in flood-prone areas, causing environmental, societal, and economic losses such as water pollution, crop failure, casualties, health problems due to water-borne and vector-borne diseases, infrastructure damages (e.g., buildings, roads, power supplies, telecommunications), and economic activity disruption (Rosyidie, 2013;Bubeck et al, 2017;Kheradmand et al, 2018;Sholihah et al, 2020;Merz et al, 2021). It was estimated that around 21 million people are affected by river floods worldwide annually, and the number can increase to 54 million people in 2030 due to climate change and socio-economic development (Ward et al, 2013;Winsemius et al, 2013;Luo et al, 2015).…”