MANILA -- Metro Manila's main water source, the Angat Dam, is facing tough times from drought-driving El Niño phenomenon in the first half of 2019.

Near-nil rainfall amidst El Niño and no reduction in Angat's water allocation for March, April and May will affect the June supply of irrigation water from the dam, Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) hydrologist Richard Orendain noted.

"Angat's June water level can dip below 180 meters," he said Wednesday (Feb. 20) on the side of a climate forum in Quezon City.

Authorities suspend release of Angat water for irrigation when the reserve in the dam reaches critical low level, to ensure availability and continuous supply of water for Metro Manila.

Orendain said reducing Angat's water allocation as early as possible and practicing water conservation in the dam's service areas will help prevent the facility's water from reaching the critical level this June.

"There may not be much rain but Angat's water can be managed," he said.

In its latest outlook, PAGASA said a weak El Niño is already present in the tropical Pacific.

El Niño will likely continue until the April-May-June 2019 period, PAGASA said.

PAGASA isn't discounting a possible delay in onset of the rainy season this year due to El Niño.

Such onset is normally between the second half of May and early part of June.

Angat Dam recovers after the rainy season sets in as rainfall helps increase the water reserve in the facility.

According to Orendain, Angat Dam is able to provide water for irrigation, Metro Manila and power generation at present.

"Angat is operating normally," he said, noting that the dam's water allocation at present is 87 cubic meters per second (cms).

He expects normal operations in Angat until May's end.

However, reducing Angat's allocation to about 67 cms beginning March will help conserve water in the dam so it can be available for a longer period, he noted.

The possible delayed onset of this year's rainy season highlights the need to prolong the availability of Angat water.

In a statement released Wednesday, PAGASA Administrator Dr. Vicente Malano said El Niño will likely cause below-normal rainfall around the country in the forthcoming months.

"Impacts also include slightly warmer surface temperatures in varying degrees from place to place and from time to time," he further said in the statement.

PAGASA forecast way-below, below- and near-normal rainfall this March, April and May, respectively, in the watershed hosting Angat Dam.

Among provinces where PAGASA forecasts dry conditions by March 2019’s end is Bulacan, where Angat Dam is located.

Dry spell is possible in Bulacan by the end of April, PAGASA also said.

According to PAGASA, dry condition is a state marked by two consecutive months of below-normal rainfall.

PAGASA added that dry spell is a state characterized by either three consecutive months of below-normal rainfall or two consecutive months of way-below normal rainfall. (PNA)