The Metropolitan Manila Development Authority (MMDA) said the city’s drainage system was overwhelmed by an “extraordinary” localized thunderstorm over the weekend, underscoring the urgent need for climate change adaptation measures like rain catchments.
On Monday, MMDA chairperson Don Artes disclosed that data from the Science Garden monitoring station in Quezon City showed 105 millimeters of rainfall in just one hour Sunday.
“If you compare it with the global average of 75 millimeters per hour, you will really see that this is extraordinary,” Artes said. “Our drainage systems were not designed to handle this kind of downpour.”
He cited the rainfall was equivalent to more than five days’ worth of precipitation. This explained why traditionally flood-free areas like Katipunan Avenue and parts of the University of the Philippines experienced unusually high water levels.
Following the flooding, the MMDA held an emergency meeting to discuss long-term solutions, including constructing rainwater catchment facilities.
The agency is coordinating with Quezon City officials, climate scientist Mahar Lagmay and other government bodies to identify open spaces for the facilities.
Possible sites include parts 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,” Artes explained. He said these projects could be completed within a year and a half since they will be built on open lots rather than busy roads.
The MMDA has identified initial funding with the help of the Department of Budget and Management to support two to three catchment sites this year.
Artes added that while the MMDA will focus on catchments and drainage upgrades, larger flood-control structures fall under the purview of the Department of Public Works and Highways.
“This is really a wake-up call,” he said. “The extraordinary rains in Quezon City are an effect of climate change, and we have to adapt.”