The rain can’t get all the blame for tragedies in places like Angra dos Reis, in Rio de Janeiro, Brazil, where 52 people died last week, says José Oswaldo Araújo, a professor of geosciences at the University of Brasília (UnB).
There are other reasons for mudslides that bury people and buildings, he says. Among them: a lack of urban planning and no land use controls.
“Human intervention is the biggest factor, it upsets the balance in nature,” he says.
On Ilha Grande, according to Araújo, human occupation and deforestation left the soil unprotected making it easier for rainwater to infiltrate into the ground. But the soil can only absorb a limited amount of water. When the soil is saturated it will slip off the bedrock and roar down a mountain. It will turn into a river of mud.
Araújo complains that technical knowledge about risks of landslides in hillside construction is available but rarely used. He declared that after the tragedies of the last few weeks there is clearly a need for more rigid control, oversight and inspection.
Araújo concluded by saying: “You do not have to be a prophet to see that after the rainy season the dry season will come and then nobody will talk about this problem any more – until January 2011, when new accidents happen.”
A cold front has moved through Rio Grande do Sul (Brazil’s southernmost state) and will move northward over the next few days. Result: more rain in southern Brazil.
Heavy rain is forecast in the coastal areas of the states of São Paulo and Rio de Janeiro where they caused so many problems last week. The rain is expected to continue through Friday.
The Rio Grande do Sul state highway department is already trying to discover why part of the bridge at Agudo over the Jacuí River collapsed on Jan 5.
The bridge connects the municipalities of Agudo and Restinga and is a little over 300 meters long. A section of the bridge of around 100 meters just fell into the river.
At the moment the bridge collapsed some 20 to 30 people were standing on it looking at the sight of the flooded river and raging waters. At this time at least five people are still missing among them the vice mayor of Agudo, Hilberto Boeck.
The search for victims has been made difficult by more rain. Helicopters have been unable to fly and the Civil Defense says work on the ground has also been hampered.
The bridge in Agudo over the Jacuí River is 300 meters long and was built in 1963.