UP institute warns: Monterrazas flood study has limits, does not settle liability 

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April 28, 2026 | 8:00am

MANILA, Philippines — The University of the Philippines' Institute of Environmental Science and Meteorology has cautioned the public against reading its flood modeling research as a verdict on who is responsible for the deadly 2025 floods in Cebu.

In a statement to Philstar.com, IESM confirmed that researchers from its Environmental Hydrology Laboratory, led by Dr. Mayzonee Ligaray, conducted the study that has driven recent public discussion on the role of the Monterrazas de Cebu hillside development in the Typhoon Tino floods. 

But the institute stressed that "like all scientific studies, their analysis was conducted on the basis of specific assumptions, defined model boundaries, and particular research objectives," and that findings should only be interpreted within that context.

It added that the widely shared study's findings "neither determine nor preclude liability for any involved party."

Slater Young's claims

The statement followed a video posted on April 19 by celebrity engineer Slater Young, co-founder of the luxury project built by Mont Property Group, in which he cited the UP study as purported proof that the development did not cause or worsen flooding that killed over 100 people in Cebu.

The IESM, without naming Young, responded that it emphasizes "the importance of interpreting scientific findings within their proper technical scope and alongside broader multidisciplinary and community considerations."

Ligaray told Rappler on April 21 that the study was not yet finished. The research findings shared on social media March 2 covered only two of six river basins — Guadalupe and Kinalumsan — with four more still to be simulated.

Caveats

In separate comments to Sustina, an environmental news outlet, Ligaray said the research should not be treated as an Environmental Impact Assessment, the formal legal process used to evaluate a project's full environmental consequences and the basis for issuing an Environmental Compliance Certificate.  

Ligaray told Sustina the results for the first two river basins showed that Monterrazas' detention ponds "acted as a buffer," but she qualified that "we need to consider that this is a basin-wide flooding, which means that there are other factors that our watershed and flood models have taken into account."

The DENR temporarily shut down Monterrazas' operations after finding the project had violated 10 of 33 conditions in its Environmental Compliance Certificate, including insufficient drainage systems.

The department's Region 7 office has since lifted the cessation of operations order against the Monterrazas development project.  

Young's video was posted the same weekend the DENR clearance was announced.