THE government is reviving the P90-billion Parañaque Spillway Project to provide additional drainage for Laguna de Bay as another planned flood-control project is expected to divert more water into the lake.
The Department of Agriculture (DA) and Laguna Lake Development Authority (LLDA) said the long-delayed project could also improve water circulation, support fisheries production and strengthen the lake’s role as a freshwater source.
First proposed in the 1970s, the 10.5-kilometer spillway would run at least 50 meters underground and connect Laguna de Bay to Manila Bay.
Construction is expected to take at least a decade once the project begins.
LLDA General Manager Leopoldo Parumog said the spillway has become more critical with the planned Manggahan Control Gate Structure, which would divert floodwater from the Marikina River into Laguna de Bay.
The Japanese-funded Manggahan project is designed to divert up to 2,400 cubic meters of floodwater per second to help reduce severe flooding in Metro Manila.
That volume is equivalent to about one Olympic-size swimming pool being discharged into the lake every second, according to the DA.
While the Manggahan project would reduce flooding along the Marikina River, the additional water could raise Laguna de Bay levels and increase flood risks in lakeshore communities unless more drainage capacity is built.
Agriculture Secretary Francisco P. Tiu Laurel Jr. said better water circulation and flood management could also help restore the lake’s ecological condition.
‘Laguna de Bay is one of Metro Manila’s most important food baskets and our most affordable source of bangus [milkfish],’ Tiu Laurel said.
‘If we restore the lake’s health by improving water circulation and managing floods better, we can raise fish production, increase fisherfolk incomes, and improve raw water quality, which could eventually help lower water treatment costs for consumers,’ he added.
The project, however, has faced concerns from residents of Muntinlupa City and Bacoor City over possible displacement and the risk of shifting flood problems from one area to another.
Muntinlupa is where the tunnel would draw water from Laguna de Bay, while Bacoor is where excess water would be discharged into Manila Bay.
Tiu Laurel said the DA and LLDA would work with the Department of Public Works and Highways, Department of Environment and Natural Resources, local governments and private stakeholders to address these concerns.
‘The challenge is to show that this is not simply another flood-control project,’ he said. ‘Done right, it is an investment in food security, climate resilience, and long-term water sustainability that will benefit millions of Filipinos.’
Maynilad Water Services Inc. already taps Laguna Lake as a raw water source for millions of customers in Metro Manila and Cavite, including Muntinlupa and Bacoor.
The DA said improving water circulation and reducing pollution buildup could improve raw water quality and eventually lower treatment costs.