The water level of Angat Dam in Norzagaray, Bulacan surged by nearly nine meters in 24 hours on Monday as heavy rains continued to pour over Luzon, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) reported.

Pagasa hydrologist Jofren Habaluyas said the dam recorded the largest increase among monitored reservoirs, rising 8.66 meters over the past 24 hours.

“Angat Dam received the most significant change over the past 24 hours, almost nine meters, or 8.66 meters,” Habaluyas said in a DZBB interview Monday.

The reservoir water level (RWL) reached 170.47 meters at 8 a.m. on Monday, up from 161.81 meters on Sunday.

It has risen for seven consecutive days, from 156.61 meters on 4 August to 170.47 meters on 10 August.

Habaluyas said the water level had exceeded the 160-meter critical level and was nearly 20 meters higher than its lowest recorded level of 150 meters in July.

La Mesa nearing spill level

Meanwhile, the water level of La Mesa Dam in Quezon City reached 80.11 meters at around 10 a.m. Monday, just 0.04-meter below its spilling level of 80.15 meters, according to Pagasa.

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

Pagasa warned that an overflow could affect low-lying communities along the Tullahan River, particularly Fairview, Forest Hills Subdivision, Quirino Highway, Sta. Quiteria and San Bartolome.

The Camanava area — Caloocan, Malabon, Navotas and Valenzuela — could also be affected by flooding.

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

The agency said it would continue monitoring La Mesa Dam and provide updates to agencies and local government units concerned.

Agno dams release water

Several dams in the Agno River Basin in Northern Luzon also opened their gates as their water levels rose.

Pagasa reported that Ambuklao Dam in Benguet opened seven gates, releasing 467.43 cubic meters of water per second.

Binga Dam, meanwhile, continued releasing water through six gates, with a combined gate opening of four meters and an outflow of 522.56 cubic meters per second.

Habaluyas said the water released from Ambuklao and Binga was being caught by the San Roque Dam in Pangasinan, the last major dam in the Agno River system.

“The waters from these dams are being caught by San Roque Dam,” he said.

The San Roque reservoir level also rose sharply, reaching 254.77 meters Monday, up from 239.72 meters Sunday — an increase of about 15 meters.