Alternative infrastructure projects are being considered by the government to prevent water from Laguna de Bay to overflow and cause massive floods in Metro Manila, Rizal, Laguna and Cavite.
A study “Master Plan for Flood Management in Metro Manila and Surrounding Areas” conducted by the Department of Public Works and Highways (DPWH) and funded by the World Bank, said the government could build a circumferential dike around the 80-km. vicinity of Laguna Lake. The dike will also serve as a road connecting the various areas.
Engr. Cesar Cortez, officer-in-charge of the Special Projects Division of Rizal province, explained that the dike would be built kilometers higher than the water level of Laguna de Bay to prevent water overflow in areas near the lake.
The Laguna Lake Development Authority (LLDA) previously recorded the highest water level in the lake to 13.95 meters during the onslaught of Typhoon Ondoy in September 2009.
Floodgates linking to existing rivers near the lake could also be built around the dike. This is to ensure that the excess water would be pumped out to prevent it from overflowing beyond the dike.
Engr. Augustus Pascual, Planning and Development Officer IV of the province, added that the dike could be maintained through the government’s Build, Operate and Transfer (BOT) Program. Through this program, certain income-generating projects (IGPs) could be formed more or less than a kilometer from the shoreline, the dike included.
Besides the said circumferential dike and road, the study also suggested that water-impounding reservoirs could be built along the towns of Rodriguez, San Mateo and Antipolo. This is for excess water from the Marikina Watershed to flow onto these catch basins and avoid flooding in nearby low-lying areas.
Cortez and Pascual both said that the circumferential dike and road and water reservoirs would require massive funding, since they are considered as “mega-projects.”
“In our reckoning, it would take at least five years before both the dike and the reservoirs could be finished,” Cortez added. Pascual added it would be better that the projects could be built at the same time.
Cortez and Pascual did not discount the option of dredging the whole Laguna de Bay.
Pascual mentioned that these projects could also receive resistance from fishermen and fishpen operators in the lake.
At present, they mentioned that the only structure controlling the flow of floodwater in Laguna de Bay is the Napindan Hydraulic Controlling Structure, located along the Pasig River. It restricts the flow of floodwater both from the lake and Manila Bay.