Study warns of severe landslide risks across upper Marikina watershed

Research into the Upper Marikina River Basin Protected Landscape (UMRBPL) has revealed alarming levels of landslide susceptibility across more than four-fifths of the protected area, according to a 2026 study. Slope gradient emerged as the dominant contributing factor to landslide hazard in the region, pointing to the critical role of topography in determining geological instability.

The findings arrive in the wake of recent geological activity in the area. Earlier this month, a landslide struck Baras, Rizal, displacing approximately 50 meters of the Marilaque Highway and blocking nearly four kilometers of the critical thoroughfare. The incident highlighted the real-world consequences of the vulnerabilities identified in the research.

Authorities and environmental officials have expressed concern about the study's implications for the densely forested watershed region. The UMRBPL, which supplies water to Manila and surrounding areas, serves as a crucial natural resource and ecological zone. Experts emphasized that the high concentration of vulnerable terrain necessitates comprehensive preventive strategies, including enhanced monitoring systems and improved land management practices.

The research suggests that policymakers must prioritize infrastructure resilience and ecosystem protection measures in the upper watershed. Stronger building codes, reforestation initiatives, and early warning systems have been cited as potential approaches to mitigating landslide risks in the susceptible areas.