The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) on Tuesday, March 12, said the water level of the major dams in the country has been experiencing a continuous decrease due to significant rainfall reduction. 

PAGASA Hydrometeorological Division Hydrologist Oyie Pagulayan told the Manila Bulletin in a phone interview that the trend of the water reservoir in the past two months up to this date is declining. 

On the daily average, Pagulayan said the water level has decreased by 0.1 to 0.3 meters since January 2024. 

“Based sa datos noong January to February ay walang significant na pag-uulan within the watershed, so iyon kasi ang nagrereplenish ng tubig sa mga dams, so far iyong mga narerecord na pag-ulan ay napakaliliit, so mas mataas iyong rate ng utilization kaysa iyong pagreplenish (Based on the data from January to February, there was no significant rainfall within the watershed, which is responsible for replenishing water in the dams. So far, the recorded rainfall has been very minimal, resulting in a higher rate of utilization compared to replenishment),” Pagulayan said. 

In Angat Dam, the water level on Tuesday, March 12, decreased by 0.30 meters (m) from its elevation on Monday of 203.08 m to 202.78 m. 

Meanwhile, the Ipo Dam water level showed no significant change as there was little difference of 0.01 m from the previous record of 99.50 m to 99.51 m. 

Other dams that had water level reduction include La Mesa Dam at 0.4 m, Ambuklao Dam at 0.21 m, San Roque Dam at 0.24 m, Pantabangan Dam at 0.29 m, Magat Dam at 0.5 m, and Caliraya Dam at 0.2 m. 

Pagulayan said Binga Dam water level increased by 0.12 meters from 569.60 m to 569.72 meters. 

Pagulayan noted that multi-purpose dams such as Angat, San Roque, Pantabangan, and Magat have their requirements on the amount of water level contained or the “rule curve,” which if continuously not met, would make its service areas suffer. 

While she also said Angat Dam still has enough amount of water level to support particular areas, as the reservoir water level remained at 202.78 on Monday, while the rule curve was only at 194.81 m, Pagulayan advised that the usage of water resources should still be done carefully. 

“Ang panawagan ni PAGASA, magtipid or maging maingat sa pag-gamit ng tubig kasi aproaching na tayo sa summer, so definitely less iyong pag-ulan and isa rin pong loss within the watershed ay dahil sa rate ng evaporation, so mataas iyan kapag mainit at kasama iyon sa part ng losses ng isang reservoir (PAGASA's call is for everyone to conserve and be cautious in using water because we are approaching summer, so there will definitely be less rainfall. Another factor contributing to the loss within the watershed is the rate of evaporation, which is high during hot weather, and that's included in the losses of a reservoir),” she said.