Water supply to the two largest Brazilian metropolitan regions

The Sao Paulo Metropolitan Region (SPMR) is heavily industrialized and it is the most important economic centre of Latin America. It is the home to over 20 million people. The Rio de Janeiro Metropolitan Region (RJMR) was in the past the country's capital city and is presently the second most important economic centre of Brazil. It is the home of 12 million people. Although the two metropolitan regions are 400 km apart, they increasingly depend on water from the same source. Rapid urbanization and economic development in both areas have increased demand for water. With insufficient collection and treatment of sewage and with the current unprecedented drought, local sources of water are not sufficient and/or unsafe. As a result, the two giant metropolitan regions now dispute water from the same river, the Paraiba do Sul, which runs for roughly one thousand kilometres crossing three Brazilian states: Sao Paulo, Minas Gerais and Rio de Janeiro State. Recently there was a change of the operation rules for reservoirs located in the basin, conceived originally to optimize hydropower production, in order to accommodate the new situation. This paper explains the political, technical, and water-energy consequences of this dispute for water. (C) 2015 The Authors. Published by Elsevier B.V.