Measures and solutions for flood management in South America: Selected cases from the South and South-East of Brazil

South America has been scenario of intense transformations during most of the 20th century, in particular during the second half of the century. Intense social and economic developments in important parts of the region were characterized by: a) rapid growth of population and the need to strongly expand the occupation of land and the use of water resources; b) very intense and sometimes chaotic expansion of urban areas and a high demographic concentration in rapidly growing cities; c) industrialization process with variable intensity in different countries of the region and d) expansion of basic infrastructure in general, also including the development of water related infrastructure. The paper is focused oil current problems related to floods and mitigation measures in the region. Since a comprehensive treatment of all aspects and the variety of local conditions in South America is beyond scope and possibilities of this paper, illustrative cases of the recent experience in the relatively densely Populated South-East and South of Brazil are presented and discussed. Main topics included in the paper are: The development of water resources of the Parana River and its tributaries, the largest river basin in southeastern Brazil, and its pioneering importance as a school for subsequent practices in the multi-purpose uses of water, water resources management and flood management. The rapid urban expansion of the main cities of the region: Sao Paulo, Curitiba, Porto Alegre and their vulnerability to floods generated in the urbanized areas and in upstream catchments. The case of smaller towns in the region. The development of strategies and the implementation of measures to cope with severe flooding conditions due to urbanization and other land use changes. A review of critical factors restricting the sustainability of adopted solutions and the attempted ways to overcome difficulties in recent cases. Conclusions are drawn oil the basis of the reported cases.