TO BE CLEAR, this is not an article about the controversial Ungka flyover that has been making waves in Iloilo City. Although that building may be sinking in places it should not be, the real problem is much more severe: literally sinking this thriving city every year.
In a study on land subsidence in Iloilo City, the University of the Philippines Resilience Institute recently revealed that some areas are sinking at an alarming rate of up to 9 millimeters annually.
While it might not seem like much, that represents an actual freefall in geological terms. Even though it might be easy to write these numbers off as just another statistic or a case of “that’s not my problem,” the truth is much more critical.
Iloilo’s dire situation is not unique to it. Cities worldwide, including Venice, Italy, Lagos, Nigeria, and Jakarta, Indonesia, are dealing with comparable or even more severe problems. For instance, Jakarta is sinking 6.7 inches on average per year, which has forced the Indonesian government to take on the enormous task of moving the capital to another location to avoid the encroaching sea.
Lagos, the largest city in Africa, is in danger of being swallowed by rising waters and crumbling coastlines. And then there’s Venice, the archetypal example of an urban sinking, where the Adriatic gradually claims centuries’ worth of history.
However, why is this happening? Why are these formerly stable cities abruptly sinking beneath the earth’s surface or being engulfed by the ocean?
Numerous culprits are involved, including the compaction of sediments due to natural processes, excessive groundwater extraction, and rapid urbanization. Combining rising sea levels with climate change creates the perfect storm for land subsidence.
The geographical location of Iloilo and the city’s infrastructural difficulties exacerbate the situation. Mandurriao, Molo, and La Paz are some of the most severely affected districts. Between the Tigum River, the Dungon Creek, the Iloilo River, the Iloilo-Guimaras Strait, and an assortment of fishponds, swamps, floodways, and salt beds, La Paz and its baby district, Lapuz, and, I calculatedly hypothesize, even the City Proper, practically float. Despite being beautiful, this abundance of water is gradually weakening the ground beneath these densely populated areas, causing the sinking ground we are currently seeing.
Just take a moment to compare Iloilo and Metro Manila. The latter is also sinking; subsidence rates are as high as 10 centimeters annually in certain places. The reasons are sadly well-known: excessive groundwater extraction, unrestrained urban sprawl, and inadequate land-use planning.
A terrifying situation has emerged in the KAMANAVA area of Metro Manila (Kalookan, Malabon, Navotas, and Valenzuela) due to subsidence and rising sea levels: entire communities are now below sea level. They are, therefore, susceptible to even the most minor storm surges like the Carina flood this late July. (To be continued)/PN
