By Ellalyn De Vera-Ruiz
Amid the weak El Niño episode, the water level at Angat Dam in Bulacan on Thursday reached its lowest level in five years and may even further decline to its 160-meter critical level in nine to 10 days, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said.
Due to insufficient rain over the Angat watershed, PAGASA hydrologist Elmer Caringal said there is an average decrease of 0.40 to 0.45 meters in the Angat Dam’s level every day.
As of Thursday morning, the water reservoir’s level was down to 164.02 meters from last Wednesday’s 164.48 meters.
During an El Niño event in 2014, the water level at Angat Dam dropped to 162.74 meters. But the dam’s lowest level in history was at 157.57 meters recorded in 2010, which happened during an El Niño episode.
Should there be no rains and the allocation for domestic supply is still the same, the water level at Angat Dam could reach its critical level of 160 meters in nine to 10 days, Caringal said.
Since Angat Dam’s water level fell below its 180-meter minimum operating level last April, the National Water Resources Board (NWRB) suspended the allocation of water for the irrigation requirements of farmlands in Bulacan and Pampanga from Angat Dam to conserve water and reduce the water level decline in the Angat reservoir.
NWRB also reduced the water allocation for Metro Manila households last June 1.
According to NWRB Executive Director Sevillo David Jr., the NWRB agreed with PAGASA, National Irrigation Administration, National Power Corporation, and Metropolitan Waterworks and Sewerage System and its concessionaires Maynila and Manila Water to implement some contingency plans and to maintain the 46 cubic meters per second that is being released for MWSS water supply requirements in case that the level of the dam will reach 160 meters.
But if the level continues to drop and if the dam breaches the 160-meter level, then the low-level outlet in the Angat Dam – the bottom outlet that is capable of operating below the 160-meter level – will be operational in order to address the requirements of MWSS for the domestic water supply,” David explained.
“We are closely monitoring the level in Angat in case there will be significant deviations from the rainfall projections. Rest assured that the government and our partners in the private sector are doing all actions to secure the water supply for metro manila and minimize the impacts of the prevailing El Niño phenomenon,” he added.
The NWRB executive director also appealed to the public to “do our share in water conservation efforts through responsible and wise use of water.”
“With the rains, we are having here in Metro Manila, let us also do some rainwater harvesting and recycle it,” he said. “This is important in helping in the recovery of the Angat Dam to a more comfortable level for future use and requirements.”
PAGASA has yet to declare the official onset of the rainy season, which is expected by the first half of June.
This weekend, the southwest monsoon or habagat will prevail over the western section of Luzon.
Cloudy skies with scattered rains and thunderstorms will persist over Ilocos Norte, Ilocos Sur, La Union, Pangasinan, Batanes, Babuyan Island, Zambales, and Bataan.
Meanwhile, Metro Manila and the rest of the country will have partly cloudy to cloudy skies with isolated rain showers due to localized thunderstorms.
PAGASA warned that rains, especially during severe thunderstorms, could trigger possible flash floods or landslides over low-lying and mountainous areas in the entire archipelago.