Why flood projects keep failing: No soil tests

When asked why so many flood-control structures collapse, crack, or fail long before their design life, engineers from the Department of Public Works and Highways (DPWH) gave a blunt answer: budgets have been scarce for years, and even now they still are.

The first casualty, they explained, is the part that no one sees — the geotechnical investigations.

These tests determine the type of soil or rock underneath, the depth of required foundations, and the methods to prevent seepage and erosion. Skipping this step means building on guesswork, which is why dikes tilt, walls seep, and revetments wash out after just one season of heavy rain.

Flood control structures may look like concrete problems, but they’re really soil and water problems. Geotechnical engineering is the science of turning borehole samples, lab tests, and field drills into design choices — from foundations and cutoff walls to drainage and slope stability. Without it, projects are gambles.

Some engineers admitted that pre-construction activities like boring and lab work were often the first to be cut when money was tight.

For years, the political focus was on “visible output” — kilometers of dike to show off at inaugurations, not what lay underneath.

One engineer put it plainly: “We had to stretch pesos. You cannot show a borehole in an inauguration photo. Politically, the pressure is to pour concrete, not to drill.”

The irony? Geotechnical work usually costs less than five percent of a project’s budget. That small fraction often makes the difference between a structure that lasts decades and one that collapses within months.

The problem is also institutional. The DPWH has no in-house capacity for advanced soil studies. The Bureau of Research and Standards issues guidelines, but the actual investigations are usually outsourced.

“We don’t have our own drilling rigs, labs, or research centers,” another engineer explained. “If the funds aren’t there for consultants, then the project just moves without soil data.”

This dependency has left the agency vulnerable. When budgets run dry or procurement is delayed, projects push forward without the one thing that could guarantee stability: actual ground data.

In May 2024, the DPWH issued Department Order 75, a landmark directive making geotechnical investigations mandatory for all infrastructure projects. The order requires standard Geotechnical Plans, qualified consultants, and specific deliverables before design can move forward. Terms of reference for new projects now cite DO 75 directly, signaling that the policy is beginning to take hold.

The order builds on older manuals, like DGCS Volume 2C, which set minimum borehole depths and testing suites, and on Project Quality Assurance manuals that govern field checks.

Together, they could form the backbone of a system that drastically reduces failures — if it is actually enforced.

Consider the collapses that recently made headlines: walls keyed only a meter into riverbanks, dikes without relief drains, embankments that seep from below. All symptoms of missing soil investigations.

The engineers admitted they sometimes had to make do with outdated soil data or just a few token boreholes. They view DO 75 with mixed emotions — relief that it finally sets the rule, regret that it came too late.

“If this rule had existed 10 years ago,” one engineer said, “so many of our problems could have been avoided.”

Flood control spending is already under heavy scrutiny, with Malacañang ordering investigations into alleged anomalies. But beyond the politics, what’s often missing in many reports is the technical side. Were proper soil investigations ever done?

That’s where DO 75 could change the game. It creates a paper trail —borehole logs, lab reports, geotechnical plans — that auditors, journalists, and citizens can demand. Accountability then shifts from abstract numbers to physical soil records.

The engineers were blunt: tight budgets shaped the past — and still shape the present. But the tools now exist to build defenses that actually last. The tragedy is that they came late, after years of cracks, collapses, and wasted billions.

And the cruelest irony? The money needed to prevent these failures was always just a fraction of the whole.

The real challenge now is political will — to stop treating geotechnical work as an afterthought and recognize it as the most cost-effective safeguard against billion-peso disasters.