Angat Dam in Norzagaray, Bulacan recorded a nearly nine-meter rise in its water level over the past 24 hours, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported.

“Na-receive po ng Angat Dam ang pinaka significant na change for the past 24 hours almost 9 meters, 8.66 meters for the past 24 hours,” PAGASA Hydrologist Jofren Habaluyas said in a DZBB interview on Monday.

“Lagpas na po sa critical level na 160 and almost 20 meters ang itinaas mula doon sa lowest point niya na 150 [meters] last July po,” he added. 

(Angat Dam received the most significant change over the past 24 hours, almost nine meters, or 8.66 meters over the past 24 hours. It has already exceeded the critical level of 160 meters, and it has increased by almost 20 meters from its lowest point of 150 meters last July.)

The Angat Dam’s reservoir water level (RWL) rose to 170.47 meters as of 8 a.m. Monday (10 August) from 161.81 meters recorded on Sunday (9 August).

The latest reading also marked the seventh consecutive day of increase, with the water level continuously rising from 156.61 meters on Tuesday (August 4) to 170.47 meters on Monday.

La Mesa Dam nears to spill

Latest hydrological situationer update released by PAGASA reported that La Mesa Dam’s water level reached 80.11 meters at around 10 a.m. Monday, but remained below its spilling level. 

“Excess floodwaters in La Mesa Dam will overflow once the dam’s water level reaches 80.15 meters,” the state weather bureau said.

PAGASA warned that water from La Mesa Dam could affect low-lying areas along the Tullahan River in Quezon City, particularly Fairview, Forest Hills Subdivision, Quirino Highway, Sta. Quiteria, and San Bartolome.

The weather bureau also identified CAMANAVA—Caloocan, Malabon, Navotas, and Valenzuela—as areas that could be affected by possible flooding. 

“All residents living in the aforementioned areas, especially those living near riverbanks, are advised to remain alert for possible flash floods,” PAGASA said.

“PAGASA shall continue to monitor the hydrological condition of La Mesa Dam and provide updates to the concerned agencies and local government units,” it added. 

Other dams monitored, gates open 

PAGASA hydrologist reported that several dam gates in Agno River Basin in Northern Luzon were opened, starting with seven gates at Ambuklao Dam in Benguet, with an outflow of 467.43 cubic meters per second. 

Binga Dam, on the other hand, continued releasing water through six of its gates, resulting in an outflow of 522.56 cubic meters per second, with the gates raised to a combined height of four meters.

“The waters from these [dams] are being caught by San Roque Dam”, Habaluyas pointed out, noting San Roque Dam in Pangasinan catched waters from Ambuklao and Binga Dam, which are part of the Agno River system. 

The hydrologist noted that San Roque Dam is significant at present, as the gates of Ambuklao Dam have been open for almost two days.

The water level of San Roque Dam increased by 15 meters, with the latest water level at 254.77 meters on Monday from 239.72 meters on Sunday.

“ There is still a buffer of almost 25 meters from the normal high water level [NHWL] of San Roque, which is 280 [meters],” PAGASA hydrologist said. 

Habaluyas reiterated that San Roque Dam serves as the last dam in the Agno River Basin, with communities in Pangasinan depending on its water resources. 

The Agno River Basin is a land area in Northern Luzon where waters flow into the Agno River, with three major dams located along the river system—from Ambuklao Dam at the top and Binga Dam in Benguet at the center, down to San Roque Dam in Pangasinan.