A Brazilian hydrology expert called for a holistic approach in solving São Paulo’s water supply vulnerability in a lecture at the Center for Government and International Studies yesterday.

“São Paulo does not have a water problem, but a land use problem,” said Monica Porto from the University of São Paulo. According to her, the main challenge is to efficiently distribute the limited water resources to a city of 20 million inhabitants in light of rapid urban expansion, high population density, and pollution.

Porto advocates both demand and supply management in order to manage the water supply in a sustainable manner. The reduction of consumption and water leakage are essential in order to avoid straining the watersheds that have virtually no potential for further expansion, she said.

Porto also discussed the sociological issues that worsen the situation, such as the recent urban expansion in São Paulo—especially in poorer suburbs—due to an increase in the number of residential units housing smaller families. The water companies are reluctant to provide sewage and water access to these impoverished areas because of low profitability, she added. This trend allows the creation of slums, sometimes at the borders of the reservoirs, and causes a direct threat to the sustainability of the water supply due to the pollution caused by inadequate sewage systems.

Since the area surrounding São Paulo is divided into 39 municipalities, there is tension among them over issues of water use.

“Every big city has to go and get water from the outside ... I think there is a water transfer problem, a systemic problem in Brazil,” said environmental engineering professor John Briscoe, former World Bank country director for Brazil and professor of an undergraduate course that focuses on water management.

The World Bank loans funds to Brazil to improve the hydrological infrastructure and rehabilitate polluted areas.

Other challenges include recurring flooding of the city and the dumping of sewage waste into the river, Porto said. Prevention in these areas has achieved substantial improvements but requires further investment, she added, highlighting that “the sewage of 10 million people is discharged in the river.”

“There is no silver bullet—there are many pieces that will come together such as demand management and land management,” Briscoe said.

Graduate School of Design student R. Charles Howe said that he “wants to use urban planning in managing the situation.” Howe has experienced the conditions in São Paulo himself through a Harvard water-engineering project in Brazil during J-term.

—Staff writer Martin Steinbauer can be reached at martinsteinbauer@college.harvard.edu.