Drought has placed Sao Paulo’s Cantareira water supply system under extreme stress.
Failed rains and the water demands of 20 million people have collided to create the worst water crisis on record in Sao Paulo, Brazil’s largest city. Sao Paulo is perched on a plateau, more than 700 meters (2,300 feet) above sea level on Brazil’s eastern coast. The city is at the headwaters of the Alto Tiete Watershed, which — like all other rivers in the region — runs toward the country’s interior. This means that there is not as much water in the metropolitan area as there is further downstream. The city’s remedy is to pump 33 cubic meters (8,700 gallons) of water per second back upstream from the Piracicaba, Capivari, and Jundiai river basins through the Cantareira water supply system—a network of 48 kilometers (30 miles) of tunnels and six reservoirs. It also relies on five smaller reservoir systems that source water from within the Alto Tiete Basin.
In lieu of water rationing, Sao Paulo has decided to manage its severe drought by spending millions to tap the deepest pools of its drained reservoirs. The risky move has put leaders of one of the world’s largest water utilities under a global media microscope, and invited harsh criticism from some hydrologists and politicians.