There is a minimal drop in the water level at the major dams in Quezon City and Bulacan, Philippine Atmospheric Geophysical and Astronomical Services Administration (Pagasa) said on Thursday.
Flood Forecast and Warning System Officer Edgar dela Cruz reported that the level at La Mesa dam in Quezon City was 79.16 meters, less than a meter from the normal 80.15 m.
The level at Angat dam in Bulacan was 190.29 m. water level from the normal 212 m. In Ipo dam, 7.5 kilometers downstream from Angat, it was 99.87 m., down from the normal 100.8 m.
Ninety percent of Metro Manila’s water supply comes from Angat dam.
“Angat’s water level isn’t critical yet,” Pagasa senior hydrologist Max Peralta said.
He added that Angat can sufficiently supply water to Metro Manila up until July this year, even if it does not rain until that month, as long as withdrawal of water from the dam is in line with daily rule curve thresholds set by the National Water Resources Board (NWRB).
NWRB earlier set such daily minimum and maximum thresholds to control water withdrawal in Angat so that there will be sufficient supply for Metro Manila, Peralta said.
The lowest threshold is 180 meters, equivalent to some 390 million cubic meters of water in the dam.
“Release of water from Angat must be prioritized for domestic water supply of Metro Manila,” Peralta said.
Water from Angat is also used for irrigation and power generation.
Pagasa said Angat’s water level this year began to drop in February because of lack of rainfall there.
“Further lowering of Angat’s water level can be expected during the dry season when there’s more evaporation,” Pagasa hydrologist Elmer Caringal said.
He added that even if water level there dips by almost 30 cm. daily, latest available monitoring data indicate Angat will still have sufficient water for Metro Manila this month.
“We expect rains to begin by the third week of May so that’ll help replenish water supply in Angat,” Caringal said.
Built and first operated in the 1960s, Angat impounds water from Angat River.
Pagasa also noted that temperatures were rising.
Forecaster Aldczar Aurelio said 35.3 degrees Celsius was recorded at Pagasa’s Science Garden in Quezon City at 2 p.m. on Thursday, one of the highest temperatures in Metro Manila since the summer season started on March 26.
Tuguegarao City in Cagayan recorded the highest temperature in the country with 36.7 degrees Celsius at 2 p.m.
Aurelio said a Low Pressure Area (LPA) could enter Philippine territory by Sunday but added that this is not unusual, since between two and three cyclones usually enter the country during this month.
If it develops into a tropical depression, the LPA will be named “Domeng,” he added.