Flood fatalities in Africa: From diagnosis to mitigation

Abstract

[1] Flood-related fatalities in Africa, as well as associated economic losses, have increased dramatically over the past half-century. There is a growing global concern about the need to identify the causes for such increased flood damages.To this end, we analyze a large, consistent and reliable dataset of floods in Africa. Identification of causes is not easy given the diverse economic settings, demographic distribution and hydro-climatic conditions of the African continent. On the other hand, many African river basins have a relatively low level of human disturbance and, therefore, provide a unique opportunity to analyze climatic effects on floods. We find that intensive and unplanned human settlements in flood-prone areas appears to be playing a major role in increasing flood risk. Timely and economically sustainable actions, such as the discouragement of human settlements in flood-prone areas and the introduction of early warning systems are, therefore, urgently needed.

Debates—Perspectives on socio‐hydrology: Capturing feedbacks between physical and social processes

“…Empirical evidence shows that, when levees are built, high water levels tend to be exacerbated [Heine and Pinter, 2012;Di Baldassarre et al, 2010, 2013b. Thus, if levees are built, we simulate the human impact on flood levels by expressing the actual high water levels as W1n H H, whereby H is the flood protection level, e.g., height of levees, while n H is the proportion of flood level enhancement due to the presence of levees.…”

“…The impact of floods has dramatically increased in many regions of the world over the past decades Dankers et al, 2014;Di Baldassarre et al, 2010]. This trend looks set to worsen in the near future, as rapid urbanization continues to swell the size of the population living on floodplains above the current size of one billion, while flood levels might increase due to climate change and sea level rise [Hinkel et al, 2014;Jongman et al, 2014].…”

Socio‐hydrology: Use‐inspired water sustainability science for the Anthropocene

“…Examples of wicked problems that continue to vex scientists and policy makers include: trade-offs among ecosystems, hydropower, and livelihoods in the transnational Mekong Basin [Ziv et al, 2012]; effects of human settlements in flood-prone areas on increased flood risk and fatalities in Africa [Di Baldassarre et al, 2010]; and expanding hypoxic zones in the Gulf of Mexico resulting from nutrient loading in the agricultural headwaters of the Mississippi River [Turner and Rabalais, 2003]. Due to the urgency of these problems, contemporary scholarship should draw from natural sciences, social sciences, and the humanities, to better understand the dynamics arising from the two-way coupling between water and humans in each case.…”

Flood hazard assessment for extreme flood events

“…Taking into account all of these considerations, four types of flood events can be generally characterized as extreme flood events, including: (1) dam-break floods (Duffaut 2013;Bergman et al 2014;Raška and Emmer 2014), (2) storm surges (Chau et al 2013;Breilh et al 2014;Androulidakis et al 2015), (3) flash floods (Moussa and Bocquillon 2009;Martínez Ibarra 2012;Foulds et al 2014;Amengual et al 2015;Kvočka et al 2015), and (4) extreme/large river floods (Zhi-Yong et al 2013;Bruwier et al 2015;Herget et al 2015;Schröter et al 2015;Antico et al 2016). Among these types of extreme flood events, flash floods and large river floods are the most common and generally the most serious extreme events (Ashley and Ashley 2008;Di Baldassarre et al 2010), which pose the greatest flood risk to the general population.…”