Manila Water banking on Wawa, Laguna de Bay for supplemental supply with onset of El Niño

EAST ZONE concession holder Manila Water Co., Inc. said it plans to tap Wawa and Laguna de Bay for additional raw water to mitigate declining water levels at Angat Dam as El Niño takes hold.

“We continue to further improve the existing components of the supplemental resources, which are the Wawa and Laguna Lake Systems and add new components to ensure reliability and availability,” Josemar B. Emboltorio, Manila Water’s operations group director for the east zone, said at a briefing on Tuesday.

Angat Dam supplies more than 90% of Metro Manila’s raw water needs. Its water level has been dropping below critical levels with the onset of El Niño.

The capital’s two water providers were allocated of 48 cubic meters per second (cms) of raw water this month, less than the usual 52 cms, after water levels in Angat dropped below the critical 160-meter mark.

Last month, the government weather service, known as PAGASA (Philippine Atmospheric, Geophysical and Astronomical Services Administration) announced the onset of El Niño and forecast it to escalate into a “super El Niño” by late 2026, potentially extending into next year.

El Niño raises the likelihood of dryer-than-normal conditions in parts of the country, potentially triggering droughts and dry spells, while also bringing fewer but possibly stronger tropical cyclones.

To further reduce dependence on Angat, Mr. Emboltorio said the company is set to commission two new water treatment plants (WTPs) that could treat up to 420 million liters per day (MLD) of water.

The 200-MLD East Bay Phase 2 WTP, which will source from the Upper Wawa Dam, is due for completion by the third quarter.

Meanwhile, the 220-MLD Kasaykat WTP is expected to start delivering water by the fourth quarter. It sources from the eastern shore of Laguna de Bay.

The anticipated completion of the two projects is expected to add to Manila Water’s existing raw water sources such as the Calawis Water Supply System Project Phase 1, Cardona WTP, and East Bay Phase 1 WTP.

Manila Water now serves its nearly eight million customers through supply system more diversified than during previous El Niño events, with total water output hitting 1,730 MLD.

In 2019, Angat Dam and the La Mesa Reservoir registered critically low water levels, resulting in one of Metro Manila’s most severe water shortages in recent history.

Arnold Jether A. Mortera, Manila Water’s chief operating officer for the east zone, said the company is now “better equipped” against severe supply disruptions during El Niño with the integration of the Upper Wawa Dam and the expansion of its distribution capacity.

“From a system with no alternative sources in the past, we have built a more secure and resilient water supply network designed for today’s challenges,” he said.

Manila Water assured customers of stable water supply with its mitigation measures in place, though customers could also experience low water pressure.

“The situation during peak El Niño probably would be a little bit of reduction of allocation from Angat. But since we have supplementary sources and activation of two new treatment plants in the last quarter of this year, there will be no interruptions in this concession area. The worst could be just lower pressure in some areas,” Mr. Mortera said.

Manila Water supplies around 7.93 million customers across the east zone of Metro Manila, including parts of Marikina, Pasig, Makati, Taguig, Mandaluyong, San Juan and portions of Quezon City and Manila, as well as some municipalities in Rizal province. — Sheldeen Joy Talavera