The Human Impact of Floods: A Historical Review of Events 1980-2009 and Systematic Literature Review

Background
Floods are the most common natural disaster and the leading cause of natural disaster fatalities worldwide. Risk
of catastrophic losses due to flooding is significant given deforestation and the increasing proximity of large
populations to coastal areas, river basins and lakeshores. The objectives of this review were to describe the
impact of flood events on human populations in terms of mortality, injury, and displacement and, to the extent
possible, identify risk factors associated with these outcomes. This is one of five reviews on the human impact
of natural disasters

Methods
Data on the impact of floods were compiled using two methods, a historical review of flood events from 1980 to
2009 from multiple databases and a systematic literature review of publications ending in October 2012.
Analysis included descriptive statistics, bivariate tests for associations and multinomial logistic regression of
flood characteristics and mortality using Stata 11.0.

Findings
There were 539,811 deaths (range: 510,941 to 568,680), 361,974 injuries and 2,821,895,005 people affected
by floods between 1980 and 2009. Inconsistent reporting suggests this is an underestimate, particularly in
terms of the injured and affected populations. The primary cause of flood-related mortality is drowning; in
developed countries being in a motor-vehicle and male gender are associated with increased mortality, whereas
female gender may be linked to higher mortality in low-income countries.
Conclusions.
Expanded monitoring of floods, improved mitigation measures, and effective communication with civil
authorities and vulnerable populations has the potential to reduce loss of life in future flood events.