Heavy downpours still haunt Jakarta
Damar Harsanto, The Jakarta Post, Jakarta
Amid fears that Tuesday's torrential rains, which caused flooding in some parts of the capital, would recur, the Meteorology and Geophysics Agency (BMG) predicted that heavier downpours were imminent.
"What worries us is that the tropical typhoon from Australia has still to come," said the agency's head of forecasting and meteorology services, Achmad Zakir, recalling that the storm was expected to arrive between January and February this year.
Should the storm come, it would carry with it moist winds from waters off Java, resulting in possible heavier rain in most parts of Java, including Jakarta, Zakir told The Jakarta Post.
Zakir, however, was unable to tell exactly when the storm and downpours would arrive.
On Tuesday, the heavy downpours caused many parts of the capital to be inundated with water. They also caused heavy traffic congestion.
"As of today at about 11 a.m., the water still inundated a part of Jl. Mampang Prapatan, South Jakarta, to about half the height of a car tire," a motorist said on Wednesday.
While the normal rainfall was 20 millimeters (mm) to 30 mm, reports from BMG revealed that Tuesday's rainfall reached a peak of 109.2 mm at Ciledug in the southern part of Jakarta. At Cengkareng, Tangerang and Kedoya, West Jakarta, the more than five hours of rainfall amounted to 81.4 mm and 80.2 mm respectively, while at Halim in East Jakarta it was 75.9 mm. The rainfall was slightly less, at 59.2 mm, at Kemayoran, Central Jakarta.
Zakir warned that further flooding could be expected at any time, as the city would receive an abundant amount of rainfall.
The agency also estimated earlier that a full moon during this rainy season could spell flooding for parts of the capital.
The tides are high during full moon. As the moon's gravitational pull reaches its peak, it drags the water on the earth's surface to its highest level.
Therefore everyone, particularly those living near the sea, should be alert to possible flash floods when it rains hard during a full moon.
According to the agency, the full moon will occur twice, on Jan. 28 and Feb. 27.
Besides the tidal impacts from a full moon and localized heavy downpours, flooding could also result from heavy downpours that occurred at the upper reaches of the Ciliwung and Cisadane rivers in the Bogor area.
Should heavy rain occur in the upper reaches of the rivers, the water will flow along 13 rivers through the city, possibly resulting in floods here, even though it may not be raining in Jakarta itself.
However, an employee at the city administration's flood control center, Nurdin, claimed that water levels at several of the city's main water gates were still safe.
"The water level at Depok water gate is 115 centimeters (cm) today, while at Pesanggrahan water gate it is 75 cm, or far below the critical level of around 300 cm," he said.
Nurdin said that when the downpour occurred on Tuesday, water levels at Depok and Pesanggrahan water gates rose only slightly, to 125 cm and 85 cm respectively.
Jakarta is also prone to flooding due to the fact that around 40 percent of the capital lies below sea level and due to the city's poorly performing drainage system.