Metro Manila Development Authority (MMDA) Chairman Romando Artes on Monday said the city’s drainage system was overwhelmed by an “extraordinary” localized thunderstorm over the weekend, highlighting the urgent need for climate change adaptation measures such as rainwater catchments.

Data from the Science Garden monitoring station in Quezon City showed 105 millimeters of rainfall in just one hour last Sunday. “If you compare it with the global average of 75 millimeters per hour, makikita nyo talaga na extraordinary ito. Our drainage systems were not designed to handle this kind of downpour,” Artes said.

He noted that the volume of rain was equivalent to more than five days’ worth of precipitation, explaining why even traditionally flood-free areas like Katipunan Avenue and parts of the University of the Philippines experienced unusually high water levels.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) classified the event as a localized thunderstorm, though Artes stressed that it reflected broader climate change impacts. He added that the heavy rains were isolated to Quezon City and could recur, underlining the need for preparation.

Following the floods, the MMDA convened an emergency meeting to discuss long-term solutions, including the construction of rainwater catchment facilities similar to those in other countries. Artes said the agency is coordinating with Quezon City officials, climate scientist Mahar Lagmay, the River Basin Commission, and the Department of Environment and Natural Resources to identify potential sites for catchments.

Possible locations include portions of the Veterans Memorial area, football fields along Katipunan Avenue, and a proposed underground basin beneath the Rizal Memorial Sports Complex. “The idea is to temporarily store rainwater underground and release it slowly into natural waterways to prevent street flooding,” he explained.

Construction of these projects, which will be built on open lots rather than busy roads, is expected to take one to one and a half years. Initial funding has been identified with support from the Department of Budget and Management, which will help develop two to three catchment sites this year.

While the MMDA will focus on catchment facilities and drainage upgrades, Artes emphasized that larger flood-control structures such as dikes fall under the Department of Public Works and Highways (DPWH).

He said, “This is really a wake-up call. The extraordinary rains in Quezon City are an effect of climate change, and we have to adapt.”