WHILE Luzon is facing threats of storm surges and landslides, state hydrologists are also expecting Typhoon “Lando” to increase the water level at Metro Manila’s rain-fed water source Angat Dam closer to the 210 meters target flood season high water level.
“Our calculations show a downpour can result in a four- to eight-meter rise in Angat’s water level which was at 194.16 meters only as of 6 a.m. Saturday (Oct. 17),” said Richard Orendain, senior hydrologist of the Philippine Atmospheric, Geophysical and Astronomical Services Administration.
He noted such an increase might be possible if Lando dumps heavy to intense rain while remaining stationary for several hours after making landfall in Aurora province but before heading northward to extreme Northern Luzon.
“If such scenario happens, it’ll be good news for Angat,” Orendain said, adding that Angat Dam’s water level should at least reach the FSHWL by yearend to ensure availability of water for the following year.
But official data showed on Saturday that Angat still needs 570 millimeters of rain so its water level can reach the FSHWL.
Authorities said lack of precipitation due to the prevailing strong El Niño phenomenon is hampering rise in Angat’s water level, affecting availability of reserve water.
In its 11 a.m. severe weather bulletin released Saturday, Pagasa warned of heavy to intense rainfall within the 600-kilometer diameter of ‘Lando.’
“The typhoon covers a wide area so we expect Angat watershed to still receive rain from ‘Lando’ even if this typhoon will likely landfall in Aurora,” Orendain said. “More rain there will mean more water for Angat Dam.”
He noted Angat hasn’t received much rainfall in previous days, resulting in no significant water level rise there. “Rain there then was mostly from thunderstorms only,” he said.
In mid-2015, government stopped supplying Angat water for irrigation to help ensure availability of this commodity for Metro Manila.
Government then also began reducing allocation of Angat water for Metro Manila as Pagasa expects El Niño to last until mid-2016.
Earlier, Pagasa forecast El Niño to intensify further—possibly to a new record high.