The massive flooding that paralyzed Metro Manila on Monday, Aug. 17, should force the government to confront the issue head-on. After decades of flood-control spending, why are our cities still so easily overwhelmed by rain?

The answer cannot simply be another multibillion-peso flood control project. It must include a fundamental shift in how the government manages rainwater—keeping more of it where it falls, slowing down its flow, and turning a flood hazard into a water resource.

The urgency is unmistakable. The Metropolitan Manila Development Authority, citing a Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) report, said 201.7 millimeters of rain in Metro Manila was recorded in just five hours on Aug. 17, a deluge that rapidly inundated roads and communities. That was almost half of what Tropical Storm Ondoy dumped in 24 hours of rain in 2009.

This is where Republic Act No. 6716 deserves a fresh look. Signed by President Corazon C. Aquino on March 17, 1989, the law directed the construction of water wells and rainwater collectors, among other facilities, in barangays nationwide. It was conceived primarily to expand water access, but its rainwater-harvesting principle is equally relevant to today’s climate emergency.

The government must enforce the law—not merely as a water-supply measure, but as part of a national flood-mitigation strategy.

The private sector has already demonstrated what this can look like. SM Prime’s network of rainwater catchment systems can collectively hold about 86,000 cubic meters—roughly 34 Olympic-sized swimming pools. At SM City Masinag, the catchment basin was designed to intercept runoff in a historically flood-prone area. During Super Typhoon Carina in 2024, it collected 8,652.60 cubic meters of rainwater.

SM City La Union takes the concept further. Its 760-cubic-meter system combines stormwater storage with multistage filtration and reverse osmosis, allowing recovered rainwater to be reused for mall operations such as cleaning and cooling.

The Bonifacio Global City underground detention system, reported to have a 22,000-cubic-meter capacity beneath Burgos Circle, offers another mode. It temporarily stores stormwater underground and releases it gradually when drainage systems can cope.

The government should take these cues.

Structures in Quezon City are likewise showing that flood infrastructure systems need not consume much public space. The city government’s drainage master plan includes detention basins, retention ponds and stormwater storage. Two basketball courts—one in Barangay Tandang Sora and another in Barangay Santa Monica in Novaliches—now double as detention basins, capable of temporarily holding 1,256 and 1,700 cubic meters of water, respectively, while the Quezon Memorial Circle project incorporates detention and retention facilities.

From the private sector, the Vertis North Rain Garden in Quezon City captures and retains rainwater while functioning as a public green space.

These examples point to a better definition of flood control: not merely moving water away, but managing it intelligently.

With these time-tested systems, the government should require rainwater catchment, detention, or retention systems in appropriate public buildings, schools, government complexes, transport facilities and new large developments. Existing spaces—from parks and playgrounds to covered courts—can be retrofitted as temporary rainwater detention areas. Barangays should have functioning rainwater collectors under RA 6716, with inventories, maintenance schedules, and publicly accessible performance data.

And none of this should become another avenue for corruption. Every project must have transparent procurement, geotagged progress reports, independent engineering audits, measurable storage capacity and penalties for ghost, substandard, or overpriced projects.

The flood-control scandal should serve as a lesson for the government—that money alone does not make infrastructure work. Accountability does.

Climate resilience should not be treated as a slogan to be unveiled after every disaster. It should mean the capacity to prepare before the rain falls.

Therefore, the mindset must be: Catch the rain. Store it. Reuse it. Release it safely.

That is flood control—and water security—put into practice.