Technology offers alternative to foil floods

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.