PAGASA Monitors Four Major Luzon Dams as Water Levels Continue to Decline Ahead of Dry Season

PAGASA Intensifies Monitoring of Four Key Luzon Dams Amid Declining Water Levels

The country's water security is facing increasing pressure as the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) continues to monitor four of Luzon's largest reservoirs following sustained declines in their water levels.

While Angat Dam remains the primary concern because it supplies more than 90 percent of Metro Manila's potable water, three other critical reservoirs have also fallen well below their normal operating elevations. The trend highlights a broader challenge affecting water storage across the island rather than an isolated issue at a single dam.

Based on PAGASA's latest hydrological data, Pantabangan Dam in Nueva Ecija registered a water elevation of 175.97 meters, significantly below its standard level of 216 meters. Magat Dam in Isabela recorded 161.05 meters compared to its normal 190 meters, while San Roque Dam in Pangasinan stood at 226.83 meters, far below its usual 280-meter elevation.

According to PAGASA Climate Monitoring and Prediction Center chief Ana Liza Solis, Pantabangan, Magat, and San Roque have been placed under monitored status, requiring continuous observation by the agency's hydrology division. The classification allows experts to closely assess changing conditions and prepare for possible impacts on water supply, irrigation, and power generation.

Angat Dam, however, remains the most critical reservoir under watch. Its water level further declined to 150.91 meters, reflecting the continued effect of daily water consumption despite scattered rainfall brought by seasonal weather systems.

Reservoirs function much like savings accounts. During the rainy season they accumulate reserves that are gradually withdrawn throughout the year. When rainfall falls short of expectations, those reserves are depleted faster than they can be replenished, leaving less available before the onset of the next dry season.

To address the situation, a technical working group has been evaluating measures to improve Angat Dam's water level. One of the options being considered is cloud seeding, a weather modification technique intended to encourage rainfall under suitable atmospheric conditions.

The interagency group brings together PAGASA, the National Water Resources Board, the National Irrigation Administration, the National Power Corp., and water concessionaires Maynilad and Manila Water to coordinate strategies aimed at protecting the country's most important water source.

Solis cautioned that recovery may prove difficult in the coming months as rainfall is expected to weaken before the dry season begins next year. Authorities are hoping that a stronger northeast monsoon, or amihan, following the southwest monsoon season will provide sufficient rainfall to replenish Angat and other major reservoirs.

Current rainfall projections for November indicate that conditions will remain well below normal across the monitored watersheds. Angat Dam is forecast to receive only 29.7 millimeters of rainfall, while Pantabangan is expected to get 71.4 millimeters, Magat 77.2 millimeters, and San Roque approximately 45.2 millimeters. These forecasts underscore the importance of sustained water conservation efforts and proactive reservoir management as authorities prepare for potentially drier conditions in the months ahead.