The State of São Paulo, in Brazil’s southeast region, generates a third of the national GDP. It has around 45 million inhabitants, about 20% of the country’s population. The São Paulo Metropolitan Region (RMSP), which is the State Capital’s influence area, encompasses 39 municipalities and a conurbation of 21 million people, one of the largest megacities in the world (data from SEADE Foundation).
The RMSP is strongly linked with five other metropolitan areas in the countryside and along the Atlantic coast: Baixada Santista, Campinas, Sorocaba, Vale do Paraíba – Litoral Norte, and Ribeirão Preto. The population and the economic activities in the State of São Paulo are highly concentrated in these metropolitan areas.
Although the State of São Paulo shows the best indicators in the country regarding coverage of water and sanitation services, water stress is a blunt reality, especially in the metropolitan areas of São Paulo, Campinas, Sorocaba, and other cities in their immediate surroundings. These metropolitan areas are in the Upper Tietê River Basin and in the Piracicaba, Capivari, and Jundiaí Rivers Basins (PCJ Basins), where water availability is naturally very limited and incapable to guarantee potable water stocks for such huge concentrations. Intense water pollution reduces, even more, the water stocks, and water reuse is in lead-off yet.
Water scarcity, deep social and spatial inequalities, and infrastructure deficits in favelas and other informal settlements, especially regarding access to sewage collection and treatment services, poses major challenges for governments, the private sector, and civil society toward universalization and water security goals.
Historically, the growth of cities in Brazil was accompanied by the spreading of river pollution. Insufficient coverage of sewage collection and treatment services, lack of control of urban sprawl, and improper management and culture of solid waste disposal were among the main causes.
In São Paulo, the industrialization process and the accelerated urban growth generated dramatic social and environmental externalities. Water pollution in urban areas forced authorities to catch and transport spring water from increasingly distant sources, and from regions that also suffer from water scarcity. Rivers and streams were channeled, and their floodplains (so-called várzeas) were completely occupied by cities, generating a chronic problem of urban flooding in the lowest areas. The occupation of riverbanks by favelas and expressways also obstructed other uses, such as navigation, recreation, riverside parks, etc. This chaotic scenario negatively affects people’s quality of life and environmental perception of rivers and water in the city landscape.
As it became evident during the 2014-15 water crisis, the total water demand for multiple uses in the basins of the Alto Tietê and of the PCJ rivers no longer finds safe support on the regional water availability, even counting on the interbasin water transfers in operation and the remaining possibilities of adduction at feasible costs. According to official estimates for 2035, water demand per sector in these basins will be:
Alto Tietê River Basin: 82.8 m3/s for urban uses (public supply); 39.6 m3/s for industry (considering 27.8 m3/s only for the Piratininga thermal power plant); and 4.5 m3/s for irrigation (rural use)
PCJ Rivers Basins: 28.4 m3/s for urban uses; 11.2 m3/s for industry; and 15 m3/s for rural use
The Alto Tietê River Basin has the worst average per capita water availability in the state – around 130 m3 per inhabitant per year – and surface water demand is more than double the minimum surface water flow. The 31 m3/s transfer from the PCJ basin through the Cantareira system complements the capital’s public supply, but total demand versus the average availability with this extra water is almost 70%, which still indicates a very critical balance. In the PCJ basins, the ratio between demand for surface water and minimum water flow, including a smaller portion in the State of Minas Gerais, is higher than 80%.
Climate changes in the Southeast Region due to La Niña tend to reduce pluviosity and worsen the situation in 2020-21. Other areas in the State have also been facing water stress, such as the Pontal do Paranapanema River Basin.
Key Water Challenges
The water demand/availability ratio is critical in some metropolitan areas of the State of São Paulo, and climate change effects may worsen the situation. Water scarcity also undermines economic development as hydro-intensive activities can no longer be installed in these regions.
Insufficient investment in improving sewage collection and treatment services resulted historically in high levels of water pollution and river degradation in urban areas, as well as incipient reuse of treated wastewater for non-potable purposes.
Lack of integration of basic sanitation policies and interventions with other urban functions, such as drainage, land use control, social housing, and river landscape recovery.
A negative perception of urban rivers as environmentally degraded areas reflects on unconscious cultural behavior regarding water use and solid waste disposal.
The 2030 Water Resources Group (2030 WRG) is a public, private, civil society partnership that supports country-level collaboration designed to unite diverse groups with a common interest in the sustainable management of water resources.