The Department of Agriculture and the Laguna Lake Development Authority (LLervoir for Metro Manila and nearby provinces.
First proposed in the 1970s, the 10.5-kilometer spillway would run at least 50 meters unDA) are reviving the long-delayed Parañaque Spillway Project, arguing that the proposed P90-billion infrastructure could deliver far more than flood control by transforming Laguna de Bay into a more productive fisheries hub, and a dependable freshwater resderground, linking Laguna de Bay to Manila Bay. The project is expected to take at least a decade to complete once construction begins.
The renewed push reflects a broader shift in how policymakers view major water infrastructure, not simply as flood mitigation projects but as investments that could simultaneously improve food security, water management, and climate resilience.
Agriculture Secretary Francisco P. Tiu Laurel Jr. said the spillway would ease recurring flooding in lakeshore communities across Laguna, Rizal, and Metro Manila while helping restore the ecological health of the country’s largest freshwater lake.
“Laguna de Bay is one of Metro Manila’s most important food baskets and our most affordable source of bangus. 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,” Tiu Laurel said.
The project, however, continues to face political and social hurdles. Residents of Muntinlupa City, where the tunnel would draw water from the lake, and Bacoor City, where excess water would be discharged into Manila Bay, have long raised concerns over community displacement, and the possibility of shifting flood risks from one area to another.
LLDA General Manager Leopoldo Parumog said the spillway has become even more critical with the planned Manggahan Control Gate Structure, a Japanese-funded project designed to divert up to 2,400 cubic meters of floodwater per second from the Marikina River into Laguna de Bay to protect Metro Manila from severe flooding. That volume of water is the equivalent to the content of one Olympic-size swimming pool per second being dumped into the lake.
While the Manggahan project would reduce flooding along the Marikina River, it is also expected to increase water levels in Laguna de Bay, heightening flood risks for lakeshore communities unless additional drainage capacity is built.
Tiu Laurel said the DA and LLDA would work with the Department of Public Works and Highways, the Department of Environment and Natural Resources, local governments, and private stakeholders to build support for the project and address the concerns of affected communities.
“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.”
The spillway’s benefits could ultimately reach beyond lakeshore communities. Water concessionaire 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.
By improving water circulation and reducing pollution buildup, officials believe the project could strengthen the lake’s role as a strategic water reservoir while lowering the long-term cost of treating raw water for household consumption.
