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February 15, 2026 | 12:00am

Excessive flooding has now become associated with corruption.

While this may be partly true, it does not fully explain why flooding occurs or why some areas are flood-prone compared to others.

There are also floods that are due to natural causes, such as intense and prolonged rainfall spells or high tides coinciding with heavy rainfall, or to artificial causes, such as forest and watershed area denudation or even flood control projects gone wrong.

According to the 2025 World Risk Index, the Philippines ranks as the country most at risk of flooding. It is one of the most disaster-prone countries in the world, commonly experiencing floods, typhoons, and droughts. It has also been said that the Philippines is especially prone to hydrometeorological events, with floods accounting for over 80 percent of natural hazard events in the country over the last 50 years and causing devastating economic and social impacts.

Bulacan is one of the most flood-prone provinces in the country. And this is because of its topography and geographical location. In one article, it was noted that the low-lying province is a catch basin for floodwaters from nearby Pampanga as well as runoff water from the Angat, Bustos, and Ipo dams, all located in Bulacan. Studies have also shown that Bulacan is experiencing rapid land subsidence, or sinking, due to excessive groundwater extraction, making the province even more vulnerable to flooding, the same article said.

Interestingly, some quarters have blamed the ongoing construction of the New Manila International Airport (NMIA) in Bulacan for the floods. Some say flooding will get even worse because of the project.

Some critics of the project suggest that the airport will act as a massive barrier, blocking river discharge and exacerbating inundation in upstream communities.

Given Bulacan’s history of severe flooding, these concerns are understandable. Unfortunately, these concerns are not grounded in science.

Experts explain that the airport’s footprint sits on a coastal convergence point where the Maycapiz-Taliptip, Bambang and Meycauayan rivers drain into Manila Bay. Understanding this geography is key to debunking the barrier myth.

Historical maps and environmental impact assessments reveal that the project occupies a long-existing natural landmass, essentially an island formation. Crucially, the airport’s layout does not cut across primary channels; rather, the rivers naturally flow around the landmass before reaching the bay.

And the area is not reclaimed sea. Instead, the land was largely a byproduct of subsidence and tidal influence. Over decades, this low-lying land — much of it already below mean sea level — slowly succumbed to the water. The abandoned structures and former fishponds seen today are not evidence of a lost ocean, but of a landscape that has gradually sunk over time.

Flooding in Bulacan predates the airport. As I’ve said, the province serves as a natural catch basin for upland runoff from the north. When heavy rainfall coincides with upstream dam releases and high tides, the geography dictates that water will collect here.

Several structural factors compound this risk. These include land subsidence, where decades of excessive groundwater extraction have lowered ground elevation across the province; urbanization, in which rapid development has replaced permeable soil with concrete, accelerating surface runoff; and siltation, which has choked rivers with sediment, drastically reducing their capacity to carry water to the sea.

The airport’s developer, San Miguel Corp., has initiated large-scale dredging to combat these issues. Millions of tons of silt have already been removed from major waterways to restore depth and flow. While dredging alone cannot eliminate all flood risk in such a vulnerable landscape, it is a proactive step in a region where river maintenance has historically been neglected.

And of course, Bulacan’s water woes worsened due to the mismanagement of public infrastructure.

Treating Bulacan’s flooding as the consequence of a single project, therefore, is a result of either a lack of understanding of the province’s topography and geography or is simply an attempt to shift the blame to someone else.

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