Water levels in several Luzon dams continued to decline, with Angat Dam falling below its low water level, prompting closer monitoring from the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).
PAGASA hydrologist Elmer Caringal said some dams in Northern Luzon, including Ambuklao Dam and Binga Dam, slightly increased due to recent thunderstorms and rainfall.
“Although the levels are low, the trend slightly changed because of the rains and thunderstorms observed there,” Caringal said.
However, downstream reservoirs such as San Roque Dam continued to experience declining water levels and are nearing critical levels. As of Tuesday, San Roque Dam’s elevation stood at 229.21 meters, still above its low water level of 225 meters.
Caringal said Pantabangan Dam also continued to decline due to insufficient rainfall in recent weeks. Its water elevation was recorded at 189.81 meters, or 26.19 meters below its normal high water level of 221 meters.
Meanwhile, Magat Dam remained below normal levels at 181.63 meters, while Caliraya Dam also posted declining levels.
Caringal said the biggest concern remains Angat Dam, which supplies nearly 97 percent of Metro Manila’s water needs.
As of Tuesday, Angat Dam’s elevation stood at 179.60 meters, already below its low water level of 180 meters and 5.72 meters below its rule curve, the target level needed to meet operational requirements.
“The trend is still expected to go downward,” Caringal said, noting that Angat’s water level had previously dropped by about 0.40 meters in a day.
PAGASA expects Angat Dam’s recovery to begin around July or August during the rainy season, although the anticipated delayed onset of rains may slow replenishment.
Caringal said concerned agencies were advised to conduct cross-monitoring of the reservoir.
He clarified that domestic water supply for Metro Manila remains the priority over power generation, although declining water levels could affect electricity production if the main turbines can no longer operate efficiently.
He also warned that irrigation operations may eventually be suspended once the water level falls below 177 meters.
“Once it goes below 177, irrigation will be closed and the water will be reserved for domestic use,” he said.
PAGASA urged the public to conserve water while waiting for reservoir levels to recover during the rainy season.