The State of São Paulo contributes to about a third of the national GDP and 20% of the country’s population, which is concentrated in 6 Metropolitan Regions mainly in the São Paulo Metropolitan Region (RMSP), with more than 20 million inhabitants. Such a concentration of people and activities in a predominantly urban context marked by deficiencies in the coverage of sanitation infrastructure and by water stress, poses major challenges in ensuring the sustainability of water supply to people, economic activities, and the conservation of regional ecosystems.
Water stress is an increasingly blunt reality in the São Paulo macro-metropolitan area, especially in the metropolitan areas (MAs) of São Paulo and Campinas.
The São Paulo State, in Brazil’s southeast region, has extensive and populous metropolitan areas under water stress. As it became evident during the 2014-15 water crisis, the total water demand for multiple uses in the MAs of São Paulo and Campinas, within the basins of the Alto Tietê and the Piracicaba, Capivari, and Jundiaí (PCJ) rivers, no longer find 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. Historically, due to the insufficient coverage of sewage collection and treatment services and to the improper disposal of solid waste by the population, water pollution spread as cities grew, forcing authorities to catch and transport spring water from increasingly distant areas. River pollution and inadequate occupation of river banks also obstructed other uses, such as navigation, recreation, and creation of riverside public open spaces, and had a negative cultural impact on how people perceive rivers and creeks in the city landscape.
According to official estimates for 2035, water demand per sector will be:
Alto Tietê river basin (called UGRHI-6): 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 (called UGRHI-5): 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 the total demand versus the average availabity with this extra amount of water is almost 70%, still indicating a very critical balance. In the PCJ rivers basins, the ratio between the demand for surface water versus the minimum water flow, including the contribution areas and users in the state of Minas Gerais, is higher than 80%.
Despite the differences between these regions, both the Alto Tietê and the PCJ rivers basins are directly interconnected and show critical water balances.
Key Water Challenges
Water demand/availability ratio is critical in the most important metropolitan areas of the state, and increasing demands and climate change effects may worsen the situation.
Insufficient investment in sewage collection and treatment infrastructure, resulting in high levels of water pollution in urban areas and little percentage of non-potable reuse of treated wastewater
Lack of integration of water and sanitation related functions, such as drainage, sanitation, land use control, social housing, and river landscape enhancement
Negative perception of urban rivers and creeksas environmentally degraded areas, reflecting on cultural behaviour 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.