Gated Buenos Aires communities add to floods(1)

A satellite image of Parana River, which runs its waters off on the Atlantic Ocean.

The construction of gated communities on wetlands and floodplains in Greater Buenos Aires has modified fragile ecosystems and water cycles and has aggravated flooding, especially in poor surrounding neighorhoods.

In the 1990s a high-end property boom led to the construction of private neighborhoods in vital ecosystems, and the emergence of barriers – actual walls – between social classes in the suburbs of Buenos Aires.

In the first week of November, the “sudestada” or strong southeast wind left 19 municipalities in and around Buenos Aires under water.

The sudestada is a phenomenon that affects the Rio de la Plata basin. It consists of a sudden rotation of cold southern winds to the southeast, bringing strong winds and heavy rain. In the first week of November the wind gusts reached over 70 km an hour and more rain fell in two days than the total forecast for two months. Rivers overflowed their banks, large areas were flooded and cut off, and more than 5,000 people were evacuated.

Jorge Capitanich, President Cristina Fernández’s cabinet chief, attributed the floods to “a combination of sudestada, heavy rains, and the saturation of the water basins.”

But Patricia Pintos of the University de la Plata’s Center of Geographic Research said this confluence of factors was aggravated by the growing urbanisation and the proliferation of “barrios náuticos” – closed private neighbourhoods built on the water.

These gated communities are built near or on artificial or natural bodies of water, said Pintos, a geographer who is co-author of the book ”La privatopía sacrílega. Efectos del urbanismo privado en la cuenca baja del río Luján” (Sacrilegious privatopia: Effects of private urbanism on the lower Luján river basin).

Many of these wealthy private neighborhoods have been built on floodplains and wetlands, ecosystems that are vital to water drainage.

The new urban developments have advanced on areas that play a crucial role in managing floods, she said.

“Wetlands are getting stopped up by housing developments that ironically promote a lifestyle associated with enjoying water and nature,” said Laila Robledo, an urban planner at the General Sarmiento National University.

Four of the municipalities in the lower stretch of the Luján river basin most affected by the growth of high-end neighborhoods on floodplains and wetlands are Pilar, Campana, Escobar and Tigre, which cover more than 7,000 hectares.

 “The emergence of 65 housing developments of this kind modified the terrain at the mouth of the river and blocked drainage during weather events like the ones we experienced this month,” Pintos said.

These neighborhoods, which the expert described as “polderized closed housing developments” – a reference to polders or low-lying tracts of land enclosed by dikes – “entail major modifications of the natural topographical characteristics, not only to raise the level of the ground in order to build housing but also to create new bodies of water.”

That involves, for example, excavating to build artificial lakes and using the dirt to fill in low-lying areas.

Read Floods, Page 2