Wawa, La Mesa Dams reach spilling levels on Monday

Rizal Governor Nina Ynares urged residents in flood-prone areas to remain vigilant after the Upper Wawa Dam reached its full supply level and began spilling excess water on Monday, 21 July 2025, following hours of moderate to heavy rainfall from Tropical Depression Carina and the enhanced southwest monsoon.

In an advisory posted Monday, Ynares relayed updates from WawaJVCo, reporting that water levels at the Upper Wawa Dam started to overflow at 1:00 PM and reached 135.69 meters above sea level by 5:00 PM — well over its 135.00-meter full supply level. The dam’s spilling rate was estimated at around 190 cubic meters per second.

The Upper Wawa Dam is linked to the Marikina River and the Manggahan Floodway, both of which can influence flood conditions in downstream areas. Although the dam primarily functions as a water impounding facility to delay flooding, its continued overflow is expected to increase river levels in San Mateo, Rodriguez (Montalban), Taytay, and Cainta.

Ynares advised residents, especially those living near rivers and low-lying areas, to remain alert and ready for possible evacuation. “While the situation is serious, there is no need to panic,” she wrote in Filipino.

La Mesa Dam also spills

In a separate bulletin issued by the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) at 4:00 PM, La Mesa Dam in Quezon City also exceeded its spilling level, reaching 80.16 meters — just above its 80.15-meter threshold.

Floodwaters from La Mesa are expected to affect low-lying communities along the Tullahan River, particularly in Quezon City, Valenzuela, Caloocan, Malabon, and Navotas. Residents in these areas have also been advised to prepare for possible flooding.

The overflowing of both dams follows continuous rainfall triggered by Tropical Storm Crising and the southwest monsoon or habagat.