Dewanti A. Wardhani, The Jakarta Post 23 Feb 16;
The Meteorology, Climatology and Geophysics Agency (BMKG) has predicted that a full moon will occur this week, causing high tides off Jakarta’s coast.
BMKG spokesman Harry Tirto said the agency predicted a full moon to occur on Tuesday and warned of high tides for all areas, including North Jakarta.
“Astronomically, a full moon occurs once a month,” Harry said over the phone on Monday.
Harry said tides were usually high before and after a full moon. When the moon’s gravitational pull reaches its peak, it drags water on the Earth’s surface to its highest level. Thus, he said, if a full moon was to occur on Feb. 23, high tides would begin on Feb. 20, before dying down on Feb. 26.
This month’s high tides are expected to coincide with the peak of the rainy season, which is predicted to end on Feb. 28. Despite the coinciding schedules, however, its impacts are expected to be minimal on account of low precipitation.
Harry previously said that precipitation would be slightly lower compared to 2015, during which rainfall measured 400 to 500 millimeters per month during the peak of the rainy season, while this year precipitation is expected to measure 300 to 400 mm per month, a high precipitation level. The BMKG categorizes low rainfall intensity as 0 to 100 mm per month, mid-level as 101 to 300 mm and very high above 401 mm.
Last year, a lackluster rainy season followed by a prolonged dry season caused a water shortage scare among suppliers and residents.
Water operators in Jakarta are preparing for another shortage as a result of this year’s estimated low precipitation.
Water operator PT PAM Lyonnaise Jaya (Palyja) cut down production last year at a water treatment plant in Cilandak by 50 percent on account of the shortage. Palyja spokeswoman Meyritha Maryanie said that the company might experience a shortage this year if another prolonged dry season occurred.
Meyritha, however, said that Palyja had anticipated such a situation by developing moving bed biofilm reactor (MBBR) water treatment technology in its Cilandak plant. An MBBR biologically treats wastewater by circulating moving media in aerobic and anaerobic activated sludge environments.
The Cilandak plant is among Palyja’s four plants serving customers in South Jakarta. From the company’s 405,000 customers, drinking water for around 15,000 people is supplied by the Cilandak plant.
The other plants are Pejompongan I and Pejompongan II in Central Jakarta, with a respective capacity of 2,000 liters per second (lps) and 3,600 lps, as well as the Taman Kota plant in West Jakarta with a capacity of 150 lps.
PT Aetra Air Jakarta (Aetra) corporate secretary Pratama S. Adi said that the company would also take anticipatory measures to ensure clean water supply should the city experience another prolonged dry season.
Separately, Jakarta Water Management Agency head Teguh Hendrawan said that the agency would not let its guard down despite the lower rainfall. Teguh said all officials directly handling flooding were prohibited from taking leave and must make daily reports of conditions in all areas.
“Our cleaners are also on standby to make sure all waterways are clean. We will continue monitoring and preparing for potential flooding, although it seems high tides due to the full moon and peak of the rainy season will likely not have a big effect this year,” he said.f
