Expert says capital flood warning holds no water

BOGOR (JP): Predictions that Jakarta could be hit by massive flooding soon due to the effects of the La Nina weather phenomenon are baseless, a lecturer at the Bogor Institute of Agriculture said on Thursday.

Hidayat Pawitan, a lecturer at the institute's Geophysics and Meteorology department, told The Jakarta Post that flooding predicted to take place later this year would not be made worse by La Nina.

"The effects of the La Nina phenomenon in the form of heavier rains happen only during the dry season. During the rainy season, the impacts of La Nina are usually offset by the domination of the monsoon," he said.

The Meteorology and Geophysics Agency (BMG) recently warned Jakartans that the La Nina weather phenomenon could intensify flooding during the rainy season.

BMG predicted the level of flooding could be greater than that in 1996, when Jakarta's 10 million inhabitants suffered from the most widespread flooding in the city's history.

Hidayat reiterated that the country's weather was greatly influenced by the monsoon, a periodic wind flowing from Asia to Australia that causes Indonesia to have two major seasons: one dry and the other rainy. The dry season usually takes place from April to September, while the rainy season occurs from October to March.

"The heaviest rainfalls due to the monsoon are frequently recorded from December to February. That's why Jakarta is often inundated during those months," he said.

"There is nothing special here. Massive flooding in those months is ordinary. It's not because of La Nina.

Hidayat further explained that this year the La Nina phenomenon had already started in June with the Southern Oscillation Index, an indicator measuring both the El Nino and La Nina phenomenons, reaching a figure of eight.

The index rose to 10 early last month, he said, adding that areas could be hit by massive flooding if the index was between 10 and 20.

There is a possibility that the index may still be between 10 and 20 in October, he said. "But Java, including Jakarta, will not be affected. It will only affect South Pacific countries, including Australia. And if it affects Indonesia, it would only hit areas near Timor island," he said.

Hidayat said he was more concerned about the effects of El Nino, which usually causes droughts. If the phenomenon starts in March, it could cause a drought, he said. But if it starts in July, the dry season would not be affected at all.

Commenting on the most effective way to control flooding in Jakarta, Hidayat cited a combined system of drainage flows and dams.

"Such an integrated system could pump water out to other water storage areas when a dam reaches its maximum capacity," he said.

This system, he said, was currently being used in Tokyo and Osaka, Japan.

The two cities used to be frequently hit by massive flooding before the systems were put in place, he said. (24/hhr)