Water transfer from São Francisco river to semiarid northeast of Brazil: technical data, environmental impacts, survey of opinion about the amount to be transferred Transposição do rio São Francisco para o nordeste semiárido do Brasil: dados técnicos, impactos ambientais e enquete sobre o volume transposto

The transposition of the São Francisco River is considered one of the greatest engineering works in Brazil of all time since it will cross an extensive agricultural region of continental dimensions, involving environmental impacts, water, soil, irrigation, water payment and other multidisciplinary themes. Taking into account its importance, this subject was incorporated into a discipline of UFSCar (Federal University of São Carlos - Brazil) named "Pollution and Environmental Impacts". It was noted strong reaction against the project, even before the presentation. To allow a critical analysis, the first objective was to compile the main technical data and environmental impacts. The second objective was to detect the three most important aspects that cause reaction, concluding for the following reasons: assumption that the volume of water to be transferred was much greater than it actually is proposed in the project; lack of knowledge about similar project already done in Brazil; the idea that the artificial canal to be built was much broader than that proposed by the project. The participants' opinion about "volume to be transferred" was raised quantitatively four times: 2-undergraduate students; 1-graduate; 1-outside community. The average resulted 14 times larger than that proposed in the project, significant according to t-test. It was concluded that the reaction to water transfer project is due in part to the ignorance combined with a preconceived idea that tend to overestimate the magnitude of environmental impacts.A transposição do Rio São Francisco, uma das maiores obras de engenharia do Brasil de todos os tempos, cortará uma extensa região agrícola de dimensões continentais, envolvendo temas de caráter multidisciplinar, como impactos ambientais, água, solo, irrigação, outorga de água e outros. Devido a sua importância, incorporou-se a partir de 2005 o tema a uma disciplina denominada Poluição e Impactos ambientais, UFSCar. Mesmo antes das apresentações verificava-se forte oposição. Preliminarmente, o objetivo do trabalho foi levantar os principais dados técnicos e impactos ambientais, culminando com uma análise crítica sobre a obra. O segundo objetivo constituiu-se em detectar no público participante das exposições os três aspectos mais relevantes que causavam oposição, concluindo-se pelas seguintes razões: a pressuposição de que o volume de água a ser transferido seria muito maior do que na realidade se propõe no projeto; o desconhecimento de outra