THE Department of Public Works and Highways (DPWH) will start detention basin works in flood-prone towns along Northern Manila Bay as early as January, its chief said on Wednesday.
Public Works Secretary Vivencio Dizon added that the agency is also targeting the second quarter of next year to begin implementing a nature-based earth dike, as the agency moves away from what its chief called a ‘concrete, concrete, concrete’ approach to flood control.
Dizon said the shift will favor hybrid solutions that combine conventional engineering with nature-based interventions such as mangroves, bamboo cribs, and gabions. The effort covers the towns of Hagonoy, Obando, Macabebe, Masantol, and Sasmuan, as well as parts of Malolos City, in Bulacan and Pampanga.
‘The problem is mindset. The problem is right now, if you talk to DPWH engineers, when you ask them, flood control, flood mitigation, they will always say, ‘Let’s build a dike,” Dizon said in a mix of English and Tagalog, recounting what he told the Dutch deputy ambassador.
He said the agency is drawing on the experience of countries that have gone through the same process.
‘They also used to be all concrete, all concrete. But in some cases, they’ve even torn down the concrete, and they’re moving towards more nature-based solutions,’ Dizon said. ‘It can’t be purely nature-based, because there are things where we need concrete. But we need to study this carefully and learn from those who know and have done this before, so we don’t waste money again. We’ve already approved so much money for this, and it was just wasted.’
The earth dike is still being designed, Dizon said, noting that the government’s partners told him a plan could be ready in six months.
‘So, hopefully by the second quarter of next year, we can begin… we can already begin the process of implementing that project,’ he said.
The detention basins could move sooner because they have already been studied.
‘We can start already as early as January,’ Dizon said.
The DPWH is now only seeking help from its partners on the final conceptual designs.
‘This is not simple, like when we were kids building sandcastles on the beach. This is a complex intervention, but it’s a nature-based intervention,’ he said. ‘Let’s wait for the final designs and concepts that will come from Haskoning and ADB [Asian Development Bank] before we comment.’
Dizon cited an existing pilot in Malolos City, where bamboo cribs have been installed. He said Malolos Mayor Christian Natividad told him the cribs have been ‘very effective.’
The cribs trap sediment carried in by waves, which allows mangroves to take root naturally. Dizon said former Public Works Secretary Rogelio Singson had suggested speeding this up by filling the cribs with suitable material dredged from the Pampanga River and other rivers, and he agreed with the idea.