PAGASA warns residents in low-lying areas as La Mesa Dam nears spilling level

State weather bureau PAGASA has issued a hydrological advisory to communities near the Tullahan River, as the La Mesa Dam approaches its spilling level due to continued moderate to heavy rainfall.

As of 8:00 a.m., the water level at La Mesa Dam reached 79.69 meters, just 0.46 meters below its spilling level of 80.15 meters, based on PAGASA’s 10:00 a.m. bulletin. 

Should the dam overflow, excess water will flow into the Tullahan River, which passes through several flood-prone communities in Metro Manila.

Areas likely to be affected include Fairview, Forest Hills Subdivision, Quirino Highway, Sta. Quiteria, and San Bartolome in Quezon City; parts of Valenzuela City, particularly North Expressway and La Huerta Subdivision; and sections of Malabon.

“All the residents living in the aforementioned areas and nearby areas, especially those near the river banks, are still advised to be alert for possible floodings,” PAGASA stated. 

While overflow has not yet occurred, officials emphasized that even small increases in water levels could trigger localized flooding, particularly along the Tullahan River. 

PAGASA said it will continue monitoring the dam’s condition and coordinate with concerned agencies and local government units (LGUs) for timely updates.

La Mesa Dam is a critical component of Metro Manila’s water supply system, and controlled overspills are expected during high rainfall periods. Residents are advised to take precautionary measures and follow instructions from local disaster response units.

The Southwest Monsoon (Habagat) is affecting the country on Monday, PAGASA said in its weather forecast issued earlier today.

It said Metro Manila, Ilocos Region, Benguet, Tarlac, Pampanga, Bulacan, Cavite, Laguna, Batangas, Rizal, and Oriental Mindoro will have occasional rains. Floods or landslides are possible due to moderate to heavy rains.

In its heavy rainfall outlook, PAGASA said 50 to 100 mm of rainfall may be expected in Metro Manila, Pangasinan, Zambales, Bataan, Cavite, Batangas, and Occidental Mindoro today. —Sherylin Untalan/KG, GMA Integrated News