Technology offers alternative to foil floods

Evi Mariani, The Jakarta Post, Jakarta

Considering that experts say that Jakarta will never be free from flooding, no matter how many canals were built, widened or deepened, Baginda Patar Sitorus, a cloud-seedling specialist at the Agency for the Assessment and Application of Technology (BPPT), is offering the city "weather modification technology" (TMC) to prevent flooding.

He claims that the technology can reduce the intensity of rainfall, either by dispersing heavy clouds, stimulating clouds to produce rain before they develop into heavy clouds, or moving clouds to other locations.

Baginda said that BPPT carried out TMC for the first time last year, on Feb. 15 through Feb.19, but halted the exercise due to complaints and concern from the public.

"At that time, the public and a number of weather experts doubted the reliability of TMC. There was also growing concern from residents in Sukabumi, West Java, who feared that heavy rain would pour on their area instead of Jakarta and cause flooding," Baginda said.

He added that his TMC team had made some calculations and developed techniques to prevent such misjudgements from occurring. "Suppose we saw heavy clouds forming over Sukabumi, we would stimulate them to develop into rain before they could do much damage, then disperse the clouds that form over Jakarta and move them elsewhere," he said.

Besides that, however, TMC is also facing financial problems.

"The government, at that time, said that the cost of the operation was too high. However, I think it was nothing compared with the financial losses caused by the floods," he said.

Baginda said the cost of one hour of TMC operation was about Rp 1 million (about US$112) to 1.2 million. Since a one-day operation takes at least six sorties of 80 minutes each, the cost of one day of operating would be at least Rp 8 million. He estimated that the total cost of a 30-day TMC operation would be about Rp 2 billion.

"But we could reduce the cost if we had a more reliable weather forecast," he said.

BPPT and the Department of Geophysics and Meteorology of the Bandung Institute of Technology (ITB), meanwhile, introduced the Adaptive Neuro Fuzzy Inference System (ANFIS) forecast method in December last year.

"Our evaluation has shown that the accuracy of ANFIS was 90 percent on average," he said. "If we used this method, we wouldn't have to run a TMC operation every day. We could make flights only on days with heavy clouds as forecast by the ANFIS method," he said.

Baginda guarantees that TMC operation will be "highly reliable," as proved, he says, by a report from an independent team including representatives from the Meteorology and Geophysics Agency (BMG) and the Jakarta city administration.

"The government stopped our operation due to public concern and also skepticism from some experts, even while evaluation of the TMC operation last year showed that the rainfall in the five days that we operated was significantly reduced," he said. He added that, despite public fears, Sukabumi was not hit by floods.

TMC could be used either as an alternative technology or to complement conventional methods, Baginda said.