EXPLAINER: What is the ideal long-term flood control solution?

The Institute for Climate and Sustainable Cities estimates that the Philippine economy could lose $124 billion or more than ₱7.6 trillion in damages between 2022 and 2050, if the country's persistent flooding issues remain unresolved.

On average, the Philippines experiences 20 typhoons annually, making it one of the countries that are most vulnerable to water-related disasters, including flooding, according to PAGASA.

As typhoons hitting the country become increasingly severe and local flooding intensifies, experts say that concrete dams, walls, barriers, and dikes are no longer sufficient as solutions.

Runoff water

Picture this: when rainfall occurs on a large, open field without any infrastructure, the ground naturally absorbs the rainwater.

However, once that land is paved with concrete and buildings are erected, soaking up rainwater becomes much harder.

These excess waters are called ‘runoff water.’

In urbanized communities, managing runoff water usually depends on the drainage system.

Drainages, however, would only be effective in channeling water out to the sea — provided they are of adequate size, properly maintained, and not clogged by heaps of garbage.

What happens if an ineffective drainage system is a problem in the whole of Metro Manila, a region with rivers and located between Manila Bay and Laguna de Bay?

Flood mitigation

Experts propose the following long-term solutions:

• Sunken lawn or retention pond
• Underground tank or detention pond
• Upgrading and de-clogging of drainages
• Spillway

According to the Philippine Disaster Resilience Foundation, sunken laws and underground tanks are examples of green flood control infrastructures.

Sunken lawns, also known as retention ponds, are a landscape design that creates artificial basins. It serves as a natural sponge where runoff water can be collected and later absorbed.

Underground tanks or detention ponds are underground water storage facilities where runoff water is regulated and gradually released to mitigate the risk of flooding.

In Bonifacio Global City (BGC), there is a 22,000-cubic-meter detention tank underground of Burgos Circle that prevents flooding in the area.

The detention tank’s depth is equivalent to a four-storey building and can store water equivalent to eight olympic-sized swimming pools.

In April 2026, Quezon City announced its ongoing 3-in-1 facility at the Quezon Memorial Circle — it would serve as a park, retention pond, and detention pond.

According to Quezon City Mayor Joy Belmonte, it can store up to 651 cubic meters of water and has a filtration system with a capacity of 282 cubic meters.

The QC government said it plans to use the water for its landscape and irrigation.

Meanwhile, some experts propose upgrading and regularly de-clogging drainage systems, reforesting the Marikina Watershed, and building a spillway to carry excess water from the Marikina River and Laguna de Bay into the Pacific Ocean. — BAP, GMA News