Water management in the Metropolitan Region of São Paulo

Water management in the Metropolitan Region of São Paulo, Brazil faces several challenges, including pollution of drinking water reservoirs that are surrounded by slums, water scarcity leading to conflicts with the Campinas Metropolitan area to the north, inefficient water use, and flooding. The sprawling Metropolitan Region of São Paulo (MRSP) with close to 20 million people is the seventh most populous urban area in the world and the economic, financial and technical hub of Brazil. The main stakeholders in water management in MRSP are the state government, the state water and sanitation utility Sabesp and 39 municipal governments. A basin committee for the Alto Tietê basin, which covers the entire area of the MRSP and supplies half of its water, brings together all stakeholders. It has drawn up two master plans for the management of water resources in the basin. The first was approved in 2003 and focused on urban sprawl. The second was approved in 2009 and focused on water use conflicts.

Together the stakeholders have addressed the challenges mentioned above through massive investments in wastewater collection and treatment and slum upgrading. In the future new water sources are being developed from the Iguape river in the Ribeira valley 80 km to the south of MRSP. Furthermore, the efficiency of existing water use is expected to be increased through more reuse of treated wastewater and further reductions in water losses.

The first modern water supply system for São Paulo was built by a private company, the Cantareira Water Supply and Drainage Company of the City of São Paulo, in the 1880s. The company built a pipeline from the Cantareira mountains in the North to São Paulo, which would become the first element of what would later become the Cantareira system which now supplies half the water of Greater São Paulo. After the concession for the private Cantareira Water Supply and Drainage Company of the City of São Paulo had ended, the responsibility for water supply was taken over by the municipalities in the metropolitan area of São Paulo. In the early 20th century another private company, the São Paulo Tramway, Light and Power Company, built two dams on the Upper Tiete river upstream of what was then the city of São Paulo to produce electricity from hydropower for the growing city. The first was the Guarapiranga reservoir completed in 1906, followed by the Billings reservoir completed in 1935. Both reservoirs were initially used only for hydropower, but beginning in 1928 the Guarapiranga was also used for drinking water supply. As the city grew further, the Billings reservoir was also used for drinking water supply.

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