A recent study by geologists from the University of the Philippines-Diliman has brought attention to the alarming rate of land subsidence in Greater Manila, Metro Davao, and Metro Iloilo. The municipalities of Bulakan, Guiguinto, and Balagtas in Bulacan stand out for their severe sinking rate of 109 millimeters per year.
While this phenomenon is attributed to various factors, including excessive groundwater extraction, rapid urbanization, climate change, and the natural compaction of sediments, the reality of a sinking Bulakan town puts in jeopardy the broader metropolitan area, existing infrastructure and big projects like the ambitious New Manila International Airport city complex that will rise in Bulakan, Bulacan. This multi-billion-peso San Miguel Corporation project which is designed to cater to the growing demands of the country’s aviation and transportation sectors, promises to stand as a symbol of progress and modernization.
Bulakan, where the NMIA will rise, is a piece of land that has been inundated for a long while due to factors that include flooding from heavily silted river systems, conversion to fishponds and over-extraction of groundwater that made it more susceptible to land subsidence.
The soft, waterlogged nature of Bulakan is inherently susceptible to subsidence, particularly when subjected to the pressures of urbanization, large-scale construction, and the depletion of groundwater resources. As the land sinks, the structural integrity of infrastructures could be compromised, raising concerns about the long-term viability of the proposed airport project and surrounding structures. Moreover, the risks of flooding in Bulakan and other low-lying areas will only increase, with potentially disastrous consequences for both the airport city complex and the communities that surround it.
The sinking of the Bulacan metropolitan area could also exacerbate existing flooding problems. This could make transportation infrastructure less reliable, hinder mobility, and disrupt daily life for the residents of Bulacan and neighboring provinces.
To address these growing concerns, government, San Miguel Corporaton, and the private sector should address the land subsidence and the adverse consequences that go with it.
Government agencies should take immediate and coordinated action. The National Water Resources Board should enforce stricter regulations on groundwater extraction. The Department of Environment and Natural Resources, on the other hand, should prioritize the restoration of natural wetlands and other ecosystems — like engaging in large-scale reforestation projects, rehabilitation of fishponds, and preservation of natural floodplains — to help stabilize the land and mitigate the risks of subsidence.
Moreover, the Department of Public Works and Highways should work closely with local governments and the private sector to ensure that any infrastructure developments, including the NMIA, are designed to withstand the effects of land subsidence and climate change.
Local government units in Bulacan, particularly in Bulakan, should implement comprehensive flood control measures that account for both current and future land subsidence, bearing in mind extreme weather events driven by climate change.
The future of Bulacan — and of the NMIA complex — depends on the collective will to tackle the challenges of subsidence, climate change, and urbanization.
