Angat water level’s immediate recovery unlikely — PAGASA

By , on May 29, 2015

View of Angat Dam from San Lorenzo (Hilltop), Norzagaray, Bulacan.
View of Angat Dam from San Lorenzo (Hilltop), Norzagaray, Bulacan.

MANILA — Authorities continue urging water conservation in Metro Manila, seeing bleak prospect for the water level in this megalopolis’ main water source Angat Dam in Bulacan to immediately rise above the 180 meters minimum operating level (MOL).

“At present, there’s neither a low-pressure area nor tropical cyclone that can bring rain there,” said forecaster Aldczar Aurelio from the State weather agency Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

He said PAGASA instead forecast hot weather to continue prevailing in the area and elsewhere in the country with possible occurrence of isolated thunderstorms.

PAGASA reported Angat Dam’s water level as dipping below the MOL on May 26, reaching an elevation of 179.98 meters as of 6 a.m then.

Angat’s water level further dipped 0.25 meters to hit 179.73 meters 24 hours later at 6 a.m. on Wednesday, noted PAGASA.

“The Angat area hasn’t had rainfall enough to increase water in the dam,” said PAGASA hydrologist Richard Orendain.

He also said the volume of water withdrawn from Angat daily for various uses is more than the volume of water flowing into the dam.

“Water outflow there exceeds inflow,” he said.

What’s ideal is for water inflow in Angat to exceed outflow there, he noted.

Angat supplies water for irrigation, power and Metro Manila residents’ consumption.

Government’s protocol is to stop water supply for irrigation once water level in Angat reaches this dam’s MOL.

This year, when the drought-driving El Nino phenomenon isprevailing, however, government stopped Angat’s water supply for irrigation before such level reached the MOL.

“Supply of Angat water for irrigation already stopped on May 19,” said National Power Corporation (NPC) president Gladys Sta. Maria.

She noted reducing supply of Angat water for Metro Manila, from the regular 44 cubic meters per second to 43 cubic meters per second beginning June 1 this year, will help mitigate decline in the dam’s water.

Angat is among the dams under NPC management.

For 2015, government expects the wet season to commence around mid-June.

“When the rainy season sets in, we expect Angat’s water level to begin gradually rising,” said PAGASA Hydro-Meteorology Division OIC Maximo Peralta.

He attributed such expectation to occurrence of rain and lessening of evaporation during the wet season.

Orendain noted that even 50 millimeters of rainfall in Angat’s watershed will help raise the dam’s water level by some 1.5 meters.

“The additional water there will be sufficient for five to six days’ regular supply to Metro Manila,” he said.

He also said 50 millimeters of rainfall will bring Angat’s 6 a.m. water level this Wednesday to 181.23 meters which is above the dam’s MOL already.

Aurelio said it’s possible for thunderstorm to bring such rainfall.

There’s no certainty Angat watershed will receive the rainfall soon, however.

“That depends on where clouds will be,” he said.

Rain falls from clouds in the form of water droplets.

Earlier, Peralta observed the government this year stopped supplying Angat water for irrigation after the harvest season so farmers would have crops to sell.

“There’s not much need for irrigation water at present,” he said.

He added most farming activities at present are focused on preparing land in anticipation of the wet season.