In São Paulo, Brazil, 33-year-old computer engineer Camila Menezello Lucena was both thirsty and perspiring by the time she arrived home from work. Normally, she would have gulped down several glasses of water before taking a leisurely shower, but it was Tuesday and water was limited.
Lucena, her husband, her son and their two dogs live in Valinhos, one of several cities across the Greater Campinas region in southeast São Paulo state where authorities have been rationing water for about two weeks.
"We have to spend 18 hours a day, two days a week, without running water: from 10 a.m. to 4 a.m. the following day," she said. "But this will not solve the problem."
The problem is this: São Paulo's largest water system, the Cantareira, is at a critically low level and may run dry in 80 days if the rainfall volume does not substantially increase to fill its six reservoirs before the start of the dry season in April, according to a recent technical study by Brazilian organization PCJ Consortium.
"This is due to a meteorological phenomenon," said Jose Marengo, head of the Earth System Science Center at Brazil's National Institute for Space Research. "São Paulo had a dry spell that began in December, when the rainy season typically starts. In January, we were supposed to have between 200 and 300 millimeters of rain, but instead we had a deficit of 100 to 200 millimeters."
Marengo explained that São Paulo's droughtlike weather conditions were caused by a strong high-pressure center that, until last week, had been preventing cold fronts and, in turn, rainfall from drenching the state. But he is skeptical that the recent rains will be able to replenish the Cantareira.
"We believe that the dry spell is over, but this rain is not enough to fill the Cantareira's reservoirs. It would have to rain a lot," he said. "The water shortage risk is still there."
The Basic Sanitation Company of the State of São Paulo (Sabesp) said, however, that lack of rainfall is not the sole culprit behind the Cantareira's diminishing water reserves. This past January was the warmest in São Paulo's history, causing the state's water consumption to shoot up to extremely high levels.
Now, in February, São Paulo finds itself with a serious problem: The water supply is not able to meet the demand of nearly 12 million of its residents across both the São Paulo metropolitan area and Greater Campinas region, where 60 percent of the population depends on water from the Cantareira, explained civil engineer and Executive Secretary of the PCJ Consortium Francisco Lahoz.
Just yesterday, according to Sabesp, the massive water system fell to a historically low 17.9 percent level from an average capacity of about 50 percent.
"The current situation is really, very critical," Marengo said.
Some save water; others don't
Thirty-four-year-old software developer Leandro Zanotto lives on the outskirts of the Campinas city center, only a 30-minute drive to Lucena's home in Valinhos. Yet, unlike her, his water is not being rationed despite a shared reliance on the Cantareira system. In fact, his apartment's water tanks continue to be filled to the maximum capacity.
This disparity is due to the fact that large metropolitan areas, like Campinas, have several distribution reservoirs that act like buffers and transfer water between catchments whereas smaller areas, like Valinhos, do not and are completely dependent on each catchment, according to Ricardo Toledo Silva, professor of infrastructure technology at the University of São Paulo and former deputy secretary of water supply and sanitation for São Paulo state.
"Smaller urban areas are more exposed to the Cantareira's instant variations in water level, making them more vulnerable to water shortages," Silva explained. "But in the long term, all of the areas are equally exposed to a generalized failure of the system."
Meaning Zanotto and Lucena do share one aspect of the water crisis: the threat of a $120 fine if they are caught using water for nonessential things like washing their car and watering the garden as well as an overall expectation to limit basic tasks like bathing and cleaning the dishes.
"We are trying our best to save water during the day. For instance, we take really quick showers," Lucena said. "But I really can't imagine how bigger families with three or four kids are doing this."
São Paulo's water availability even before the dry spell was only 200 cubic meters per person per year, well below the international minimum standard of 1,500 cubic meters, according to Silva.
But Sabesp, the São Paulo state sanitation company, is not just encouraging people to conserve water; it's paying them. Those who receive water from the Cantareira are eligible for a 30 percent discount on their water bill through September if they reduce 20 percent of their consumption.
Yet in spite of earning some extra cash, many São Paulo residents remain bitter toward both city and state officials, who they believe could have prevented the onslaught of a full-blown water crisis.
"They should have warned people about this months ago so everyone could have conserved water much earlier," Zanotto said.
As population grows, so does extreme weather
While prior warnings may have helped to preserve some of the water in the Cantareira system, many other unpreventable factors were already at play.
For one, the São Paulo metropolitan area -- which receives about 45 percent of its water from the Cantareira -- is positioned in a way that does not allow it easy access to the main metropolitan river basin, Silva said.
"It is upstream from the river basin, so it's very poor on water," he said. "Usually Brazilian coastal cities evolve near the downstream extremities of river basins, where water availability is much greater. It is also located on the Western slope of the coastal mountain chain, meaning the water flows westward to the continental plain instead of flowing eastward to the coast."
Making matters worse, the São Paulo metropolitan area's water-poor placement continues to be exacerbated by its increasingly dense population, said Jerson Kelman, a civil engineer and former president of Brazil's National Water Agency (ANA).
"If you have a concentration of 10 million people, of course water supply will be a challenge unless you're close to a big river, which is not the case for that area," he said.
Many other metropolitan areas across São Paulo state, like Santos and Campinas, are also becoming progressively dense and urbanized, Silva explained. The problem, he said, is that this degrades surface permeability and groundwater recharge -- which is crucial for the replenishing of subsurface water supplies -- and leads to an overconcentration of heat in some areas, known as urban heat islands.
According to Marengo, these microcosms of heat are most likely contributing to global warming, which may be the culprit behind São Paulo's increasingly extreme weather patterns, from floods to droughts.
"Lately, whenever the rainfall comes, it is very violent and the city floods. Then, suddenly, the rain stops," he said. "We are really concerned that this climate variability -- these extremes -- will become more frequent in the future."
Expanding water supply may take years
With several million people's water security and two metropolitan regions worth 14 percent of Brazil's gross domestic product on the line, São Paulo state is in a race against time to solve a critical water problem -- not just for the short term, but for the long term.
For now, Silva said, all actors, including the São Paulo state government and civil society, are expecting the current measures -- economic incentives and water rationing -- to be effective in lowering the demand enough to avoid a "catastrophic scenario."
"We can't really say that we're in the bottom of the situation, that we are in a crisis that is impossible to overcome," he said. "We deal with the problems as they come."
But Lahoz of the PCJ Consortium doesn't want a quick fix; he wants a permanent solution.
"We have to invest in water," he said. "We're talking not only about water security in these regions but also the economic security of the country."
It's a simple matter of supply meeting demand. To accomplish this, explained Lahoz, the São Paulo state government has developed a long-term water management plan, called "The Macro-Metropolis Plan," that incorporates three of the state's major metropolitan regions, including São Paulo and Campinas. The end goal is to build infrastructure, such as reservoirs and dams, that will adequately supply water to 30 million inhabitants across 152 municipalities.
"The plan indicates that investments should be made to meet the demand of 60,000 liters of water per second until 2035," he said.
According to Monica Porto, a civil engineer and professor at São Paulo University's school of engineering, construction has already begun on a major water diversion project, called the São Lourenco Water Producing System, that will supply additional water to the São Paulo metropolitan area beginning in 2018.
But, she said, the other components of the plan -- including two reservoirs -- are still just designs.
"I wouldn't dare say that 10 years from now everything will be solved; not at all," Silva said. "I don't think that could happen."
He added, "There are still lots of things to be done."
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