In my 38 years of driving, my impression is that flooding has become a bigger and wider problem not only in Metro Manila but also in many parts of Luzon. I am no stranger to tollway traffic, but nothing I saw in the past compares with what has been happening lately at the North Luzon Expressway (NLEX).
San Simon in particular can’t seem to catch a break. The town sits at the edge of the Candaba Swamp in Pampanga, and its flooding keeps getting worse. Residents report that floodwaters now take days, if not weeks, to recede. And the problem reaches well beyond the expressway.
The Apalit-San Simon section of NLEX, including the flood-prone Tulaoc area, is low ground. It lies in the path of the Pampanga River system and the Candaba floodplain, so heavy or prolonged rain hits it hardest. And in San Simon, there is also the Tulaoc River.
Just before San Simon, if you are traveling northbound, stands the five-kilometer viaduct linking Pulilan in Bulacan to Apalit in Pampanga across the swamp and the Pampanga River. It is a reminder of the kind of land the NLEX crosses: lots of water moving across a wide floodplain.
And while the area that is currently problematic is San Simon, the stakes reach far beyond the town. NLEX connects Metro Manila with Central and Northern Luzon, carrying commuters, freight, commercial traffic, and emergency supplies. When it closes, supply chains, provincial travel, and disaster response all feel it.
So this is not just a local Pampanga issue, and it is not just a private tollway problem. The tollway operator cannot be expected to solve a regional flood on its own. The road can be raised again. The waterways can be dredged. Neither, by itself, changes how the water moves. Floodwater needs somewhere to go, especially when rivers are already high and drains stop working well.
On Oct. 12, NLEX briefed Pampanga officials on its works. Since late August, crews have been clearing and widening waterways, about 20 kilometers combined. NLEX is also putting steel sheet piles to keep river water off the highway; planning a holding pond; and waiting for the Tulaoc Overpass to be raised so the road beneath it can go higher.
These steps are necessary. But they are not enough. Dredging does not hold water. A steel wall does not remove it. Walls driven into the ground can limit the water flow toward the expressway, but they only send the water somewhere else.
San Simon’s problem is high rivers, limited drainage, silt, and nowhere to park the water for a while. And clearing just the tollway of floodwater is not the solution. The risk must not simply move to nearby communities and farmland. Water must be diverted to where it can do the least damage to anyone.
That is where a properly designed holding facility comes in. It would take in floodwater at the peak of the rain and release it when conditions downstream allow. Less water would reach the vulnerable stretches of the expressway all at once. In effect, it is the tollway sponge. And it should protect residents and farmlands as well.
The low-hanging fruit includes having the Department of Public Works and Highways (DPWH) raise the Tulaoc Overpass quickly, so NLEX can further raise a 200-meter low stretch of road underneath. The bridge needs another 1.5 meters to give tall vehicles enough clearance.
A sponge is more than a reservoir. Depending on the land, it can mean holding areas, wetlands, planted buffers, and open spaces built to flood safely. But a sponge will not make San Simon or Candaba flood-proof. However, it can catch, store, and slow water before it overwhelms drains, rivers, and roads. Anything that keeps water in place for a while, or slows it down, counts.
Water ignores town boundaries. Rain upstream raises rivers downstream. A drainage fix in one place does little if the river ahead cannot carry the water away. The Pampanga River system and the Candaba floodplain are one landscape and must be managed as one.
Small holding ponds near the expressway can ease the immediate risk to the road. But a larger storage at the basin level can add capacity, if it is shown to work and is acceptable to the environment and the community. Neither should be pursued without the other.
A basin-wide impounding or water collection area requires serious consideration. The goal is a system that gives water room to move, room to spread where it safely can, and room to stay a while, without overwhelming communities or critical infrastructure.
Under study is a proposed impounding system at Candaba that would use about 200 hectares of the roughly 2,000-hectare swamp to store floodwater temporarily. But local officials worry about more than 9,000 residents, many of them farmers who depend on the land.
The case must be proven. How much water could it hold? How would it change flood levels in nearby towns? Would it lower peak flows where they matter most? How would it work when long rains meet high rivers? Could smaller, spread-out storage do the same job at less cost to people and the environment?
A San Simon holding facility and a larger Candaba basin could complement each other. The first might ease the immediate risk to the expressway. The second could add storage for the whole region. Whether both are needed, and how to design and run them, should be settled by a study of the entire basin.
The government should also commit to a published schedule, with clear dry-season milestones and a plan for delays. Progress should be public, including the status of the works and proof that they work.
Someone must run the effort. A coordinating body, whether an existing interagency group or a new council, should bring together the DPWH, the Department of Transportation, NLEX Corp., the Pampanga provincial government, the municipal governments of San Simon and Candaba, river-basin and environmental agencies, farmer organizations, and community representatives.
Concrete and steel cannot do this alone. The agencies that plan, build, run, and maintain them must work together, because no single agency or local government controls the whole basin. The San Simon-NLEX problem needs a basin-wide plan. Drying the highway doesn’t mean flooding the farm beside it.
Marvin Tort is a former managing editor of BusinessWorld, and a former chairman of the Philippine Press Council.