EXTREME FLOOD EVENTS DUE TO INTENSE RAINFALL IN URBAN ZONES. LEARNING OF RECENT DISASTERS IN ARGENTINA

The late occurrence of various flood events in the Buenos Aires metropolitan area, as well as several urban most populated cities of the region, highlights a challenge linked the ability to analyze comprehensively the causes, effects and solutions. This analysis should consider the permanent increasing urban development, where the essence of the problem lies in the occupation of unplanned floodplains of rivers and streams. Beyond their structural vulnerability in relation to flooding of much of the urban centers, there are complementary aspects that become parallel causes to increase in reported cases of urban floods. Climate variability and climate change in the trend of the main meteorological parameters are, undoubtedly, aspects that must be considered. Along with the change in temperature recorded globally, in Argentina, there have been significant increases in the amounts of annual and daily rainfall in the city of Buenos Aires and its surroundings. Numerous flood events were recorded in the last thirty years, with significant economic losses and some of them with tragic human losses. The city of Buenos Aires has implemented a Water Management Plan, establishing guidelines for the realization of conveyance works to mitigate the effects of frequent flooding. However, these works of engineering with the application of advanced technologies do not provide the full backup to all processes of flooding that may occur in the future. Then, the great challenge in the management of urban floods is the comprehensive analysis of the problem, with an appropriate balance of structural and nonstructural measures. This is highly needed in the agglomerate of Buenos Aires (Gran Buenos Aires), home of a population of over 12,000,000 inhabitants. Facing of this problem, priority should be given to studies of non-structural measures to mitigate the effects of excess water in densely populated urban zones to fight against the phenomena of disasters due to extreme rainfall. Some of these non-structural measures are proposed in this paper.