What Japan’s $2.4-B Underground Temple Can Teach Our Flood Budget

I recently came across a YouTube feature on Japan’s colossal subterranean flood control system in Kasukabe, Saitama Prefecture—the Metropolitan Area Outer Underground Discharge Channel, popularly known as “G-Cans.”

Watching the sheer engineering scale of that 50-meter-deep underground network left a deep impression. It made me wish our local leaders and public works authorities would sit up, take serious notice, and demonstrate similar vision for our own flood-ravaged cities.

Built over 14 years at a cost of roughly $2.4 billion to $3 billion (approximately P140 billion to P170 billion), G-Cans is often called the “Underground Temple.” The subterranean facility features five 70-meter-deep concrete silos, a 6.3-kilometer connecting tunnel, and a massive surge tank anchored by 59 towering pillars.

Powered by aviation-grade gas turbines, it can drain up to 200 tons of floodwater per second directly into the Edo River. Since its completion in 2006, the facility has spared surrounding communities from catastrophic urban flooding, paying for itself several times over in prevented property damage.

Surely, but sorely, our DPWH engineers must be well aware of this technology. Through long-standing technical collaboration with foreign development partners like the Japan International Cooperation Agency, deep subterranean channels and spillways have been studied for years.

The contrast between the two nations lies not in technical awareness, but in how public funds are deployed.

Japan directed massive capital into a single, well-engineered, centralized mega-structure capable of protecting an entire basin for generations.

In the Philippines, flood control allocations amounting to hundreds of billions of pesos are frequently scattered across thousands of piecemeal, localized contracts—dredging patches, short slope-protection walls, and minor concrete revetments.

While localized maintenance has its place, this extreme fragmentation exposes a far darker reality. Dividing huge appropriations into tiny line items creates an ideal cover for massive, flagrant malversation of public funds, ghost projects, and falsified completion reports.

We thought the pork barrel scandals represented the peak of brazen greed, yet the continuous plundering of public treasury funds under the guise of “flood mitigation” proves otherwise. It is high time to prosecute and jail these corrupt perpetrators and throw away the key. Until these crooked schemes are eradicated and public funds are directed into transparent, transformative infrastructure, Filipino taxpayers will continue to drown—not just in floodwaters, but in the rampant corruption that keeps our cities submerged.

I can dream, can’t I?

JAMES D. LANSANG,
[email protected]