ENVIRONMENT-BRAZIL: Up to Neck in Water but Spouts Are Dry

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Feb 9 2004 (IPS) - Long-awaited rains finally came to Sao Paulo over the past two weeks, and have been heavy enough to flood several neighbourhoods, but half the population of this metropolis of 18 million still faces water rationing.

In addition to Sao Paulo in the southeast, several cities and rural areas in northeast Brazil have been hit since mid-January by torrential rains, unusual for their intensity and for the time of year in a region known for its climate of prolonged droughts..

Several reservoirs have had to open their floodgates for the first time in 15 years, thus aggravating the inundation.

More than 100 people have died in the Brazilian northeast, southeast and central-west, caught in the flood currents or when their houses collapsed. The Ministry of National Integration estimates that some 5,000 homes have been destroyed, leaving at least 120,000 people homeless in 16 of Brazil’s 27 states.

The northeastern state of Pernambuco has been hardest hit, with 29 deaths as of Friday. The start of the school year has been put postponed for 60,000 students because the schools have been ruined by the flooding or are serving as temporary shelter for local families who lost their homes.

There is nothing in particular, like El Niño climate phenomena, to explain the torrential rains this time, but rather it is a coincidence of traditional meteorological factors, says Marcelo Seluchi, chief of operations at the Ministry of Science and Technology’s centre for weather forecasting and climate studies, CPTEC.

In Brazil’s northeast, three factors came together, Seluchi told IPS. Two of these favoured the rains: cold fronts coming from the south reached “farther north than normal,” and the concentration of clouds that form in the tropical zone of the Atlantic occurred “farther south than usual.”

The third factor was that the rain-inhibiting force of the “cyclonic vortex”. Usually it is present over land, but this year was out over the Atlantic Ocean – too far to the east. This led to “anomalous” conditions in the region, making this one of the 10 rainiest seasons in the past four decades, says Seluchi.

The vortex is beginning to return towards the continent, and the rains have tapered off in some northeastern states, allowing cautious forecasts of normalisation in the coming days, according to the expert.

In the Sao Paulo metropolitan region, heavy rains are frequent at this time of the austral summer, as are floods. Flooding ideally could be prevented, but it continues to occur because “the city isn’t prepared, it doesn’t have the infrastructure” to divert water, says Viviane Algarve, head of customer service at CPTEC.

This year the situation was aggravated by a cold front that settled over Sao Paulo, triggering intense, intermittent rains lasting more than a week.

And there was a strange element to it all: “the pounding rain fell on some neighbourhoods, and not on others,” causing floods and destruction in specific areas, said Seluchi. The weather station set up in the Santana district, near the centre of Sao Paulo, may have made some major errors, but it did not register any rainfall.

This phenomenon could be the last straw for many ‘Paulistas’. It is difficult to explain to the public why so much rain, which caused damage to the homes of more than 21,000 people, is not going to remove the threat of water rationing.

The threat has been hovering over the Sao Paulo area since last July.

The rains were concentrated in some parts of greater Sao Paulo, but not in the Serra da Cantareira, where the main water sources are located that supply half of the 18 million residents of the metro area, Brazil’s most populous and most industrialised city.

The local sanitation company estimates that the Serra da Cantareira system is at just five percent of its normal capacity. If the area does not receive rain before the end of February, nine million people will have to go without water for as long as 36-hour at a stretch in a rotating rationing schedule.

The torrential rains falling only on densely populated neighbourhoods in the metropolitan area could be the consequence of a local climate change, in the same way that “islands of urban heat” are caused by vast areas of built-up, urbanised land, said Seluchi, but stressed that this is his “personal thesis.”

The heat, fed by the extension of buildings and roads that make up the city, contributes to the formation of clouds and storms.

The frequent Sao Paulo floods are also helped by the fact that much of the ground is impermeable, covered with asphalt and cement. Sao Paulo has only 4.7 square metres of “green area” per inhabitant. The United Nations recommends at least 12 square metres per person in urban areas.

In some of the neighbourhoods hit hardest by the recent rains, the portion of vegetation-covered land is minimal, less than one square metre per inhabitant. That means less drainage capacity, favouring floods – which have left many homes almost totally under water.