CLARK FREEPORT – Reelected City of San Fernando Mayor Edwin Santiago has vowed to boost further his city as investments bulwark despite threat of flooding being cited by scientifi c studies warning of sinking ground levels.
“It’s there,” he said in a recent forum with the Capampangans in Media, Inc., referring to the threat of flooding, even as he cited government eff orts to minimize such problem through engineering interventions.
One such study, titled “Worsening Floods around Northern Manila Bay, Philippines: Research-Based Analysis from Physical and Social Science Perspectives” cited flooding scenarios affecting not only San Fernando and other towns in this province, but as well as Metro Manila and Southern Tagalog regions. The study, done by scientists K.S. Rodolfo, F.P. Siringan, C.T. Remotigue, and C.B. Lamug, cited causes of flooding which are more serious but less admitted in flood prone areas, including Pampanga.
“Hidden underground and slow, subsidence escapes attention and allows gradual, shorttime fixes for worsening floods. Perhaps only a worst-case deluge from simultaneous high tides, storm surges and rains will educate the people and bring about proper mitigation,” the study said.
It lamented that “government efforts favor short-term political contingency over efficacy. Local politicians build wells to court votes; most national leaders are unaware of subsidence, and foreign engineering consultants ignore, deny or minimize the importance of subsidence.”
“Expensive, ineffective dredging and diking projects, funded with foreign loans that stipulate the use of foreign expertise and ignore Filipino scientists, are vulnerable to corruption,” the study noted.
It also lamented that “people whose only assets are ancestral homes and lots are reluctant to recognize that their own wells are a major cause of flooding. They demand engineering solutions, but make them even more ineffectual by refusing rights-ofway.”
While saying that “flooding can be ameliorated in the short-term by restoring channel widths and modifying aquaculture. Reforestation would increase infiltration and decrease erosion and siltation” and that “rapid subsidence will persist if groundwater use is not considerably augmented by surface sources,” the study warned that “even so, flooding from both natural compaction and global sea level rise will continue.”
“Urbanization and deforestation are important causes of the worsening floods but, in the long-term, rising local sea level is the primary factor. This is not the two millimeters per year rise induced by global warming, for regional subsidence is much more rapid,” it said.
The study has raised concerns over extraction of water from underground or aquifers.
“Dewatering and subsidence are greatly accelerated by heavy extraction of groundwater for fishponds, farms, and the rapidly growing population. Annual subsidence of several centimeters measured at many Pampanga well-sites has been independently confirmed by recent geodetic resurveys.”
The study said “we may take bleak comfort in realizing that subsidence from groundwater over-usage is a process that is self-enhancing at present, but must be self-limiting in the future, even without proper regulation. As the growing population continues to extract excess amounts· of groundwater, subsidence, and attendant tidal incursion and storm flooding can only get worse.”
“Eventually, however, either or both of two consequences will force the exorbitant use of groundwater to slow down. First, the groundwater may be so depleted, or so contaminated by saltwater intrusion that its use will have to stop. Secondly, subsidence and attendant tidal and storm flooding may render portions of the coastal plains no longer habitable, which would also result in reduced pumping. In the end, though, whatever subsidence, has happened will be permanent,” the study also said.
The study also observed that while the country’s rainy season dumps heavy water on the ground, “it is a great pity that such an abundance of rain is so seasonal, and that surface reservoirs are too small to store enough water for the agriculture, fishponds, and domestic needs of the regional population, which must rely far too heavily on groundwater.”