City told to prepare for possible floods

Bambang Nurbianto, The Jakarta Post, Jakarta

The Meteorologic and Geophysics Agency (BMG) warned on Monday of possible heavier-than-normal downpours hitting the Greater Jakarta area as the rainy season came a month behind schedule.

"We must seriously anticipate the possibility of very heavy rainfalls this season, particularly during its peak in January," chief of public meteorological services Achmad Zakir told The Jakarta Post.

There were four general kinds of downpours, he said. Light (below 25 millimeters), medium (between 26 and 50 millimeters), heavy (between 51 and 100 millimeters), and extreme (more than 100 millimeters).

It takes only 75 mm of rain a day over three consecutive days to cause flooding in the capital.

Meteorological studies show that most rainy seasons have a regular amount of downpours. If there is a delay in the start of a rainy season, its rainfalls are generally heavier than those in an extended season.

The BMG had earlier predicted the rainy season would occur in mid-October but now Zakir said the agency believed it would come later this month or in early December.

Previously, the city administration announced there were 78 flood-prone areas in the city, which were generally submerged during the rainy season. River dredging would only ease the floods, not solve them, it said.

Garbage seen clogging major rivers including the West Flood Canal would only worsen flooding as it hindered their ability to drain the city, officials said.

Zakir said he could not predict whether floods would be as bad as in 2002, when nearly two-thirds of the city was submerged.

At that time, at least 168 of 262 subdistricts in the city were swamped. Thirty-one people died in the disaster and more than 300,000 residents were forced to leave their homes and stay in temporary shelters.

Zakir warned people living near riverbanks to stay alert for possible landslides as the land in those areas was prone to erosion especially at the beginning of the wet season.

Recent precipitation in the city has led experts to predict the beginning of the rainy season. The heaviest rain so far occurred on Sunday when water flooded roads in many parts of the capital.

Zakir said the city was currently in a transitional period from the dry to rainy season. Indications of this were that the rains occurred only during the evenings or at night and were still relatively rare. Outbreaks of rain at this time of year were often accompanied by electrical storms, and stronger-than- normal winds, he said.

Zakir advised the local government to trim back tall trees as they were prone to collapsing and disrupting power supplies, he said.