SMC-cleaned rivers help ease flooding; garbage remains a challenge

Rivers cleaned and maintained by San Miguel Corporation (SMC) continued to carry large volumes of stormwater during sustained heavy rains over the past two weeks, helping reduce the risk of river overflow in several areas despite intense rainfall.

SMC cleanup teams reported no major river overflow in most areas covered by its Better Rivers PH program, except along portions of the San Juan River in Quezon City on August 17, when exceptionally heavy rainfall pushed water levels beyond critical levels.

SMC Chairman and CEO Ramon S. Ang said the improved carrying capacity and flow of waterways under the company’s long-running river cleanup initiative helped them handle higher volumes of rainwater.

Since 2020, SMC has removed accumulated silt, waste and other obstructions from major waterways, while deepening and widening critical sections and conducting regular maintenance cleanups, at no cost to government.

Ang, however, stressed that river cleanup is only one part of a broader flood-mitigation system.

The recent rains, he said, also underscored the distinction between river flooding, which occurs when waterways overflow their banks, and localized flooding, which can happen when intense rainfall overwhelms drainage systems or when drains, canals, creeks and smaller waterways are blocked or lack sufficient capacity.

According to data from DOST-PAGASA’s Science Garden station in Quezon City, 201.7 millimeters of rain fell in just five hours on August 17, with 138.7 millimeters recorded between noon and 2 p.m. The five-hour rainfall was equivalent to nearly 44 percent of the 455 millimeters recorded in Quezon City during Tropical Storm Ondoy in September 2009.

PAGASA has noted, however, that the rainfall pattern during the August 17 event was different from Ondoy. During Ondoy, Quezon City recorded about 341 millimeters in six hours, according to PAGASA Administrator Nathaniel Servando.

The intense rainfall on August 17 pushed portions of the San Juan River beyond critical levels, with overflow observed near Barangays Tatalon and Talayan in Quezon City.

Farther downstream, however, no river overflow was observed in San Juan City and Mandaluyong, where SMC’s cleanup teams are nearing completion of maintenance dredging.

SMC has removed more than 442,700 metric tons of silt and waste from the San Juan River since 2022, including 322,700 tons from 2022 to 2024 and more than 120,000 tons from maintenance work that began in September 2025.

Along the Tullahan River, which runs from La Mesa Dam through Quezon City and the CAMANAVA area before reaching Manila Bay, water levels remained below critical levels, with no major river-related flooding reported in nearby communities despite the heavy rains.

SMC said it has removed more than 1.3 million metric tons of silt and waste from the Tullahan River, including about 184,000 tons through ongoing maintenance work.

In Laguna, where Better Rivers PH has removed more than 775,000 metric tons of silt and waste, rivers in San Pedro, Biñan, Santa Rosa and Cabuyao were also observed to be flowing well. No flooding was recorded along any portion of the South Luzon Expressway.

There was likewise no flooding reported at Ninoy Aquino International Airport or in nearby communities following SMC’s cleanup of rivers and creeks around the airport in Parañaque City. More than 380,000 metric tons of silt and waste have been removed from waterways in the area under the program.

Flooding still occurred in other parts of Parañaque, including upstream areas outside SMC’s cleanup coverage, although floodwaters receded as weather conditions improved.

In Las Piñas City, where SMC is cleaning the Zapote and Las Piñas rivers, no major river-related flooding was recorded. Nearly 210,000 metric tons of silt and waste have so far been removed from the two waterways, improving their capacity to carry water toward Manila Bay.

At G. Araneta Avenue in Quezon City, historically one of the areas affected early during heavy rains, flooding still occurred, although waters receded as rainfall eased. SMC said continued maintenance cleanup has helped improve the flow of the San Juan River.

Other flood-mitigation measures also contributed to the improvement, including the opening of wall restrictions at the Matalahib Creek Pumping Station in Talayan, installation of new drainage pipes by the Department of Public Works and Highways in Tatalon, and construction of stormwater detention basins by the Quezon City government.

As floodwaters receded, however, SMC teams observed significant amounts of garbage along G. Araneta Avenue.

Improperly discarded waste remains a major contributor to localized flooding because it can clog drains, creeks and smaller waterways that carry stormwater toward major rivers.

“Cleaning up our rivers is a big help in mitigating floods, but it is not enough by itself. It is part of a bigger set of solutions,” Ang said. “The whole system has to work, from our drains and creeks to pumping stations, flood-control infrastructure and the major rivers that carry the water downstream.”

“We also have a role to play. Better-flowing rivers can move floodwaters out more quickly, but water still has to reach those rivers. We need to keep garbage out of our drains and waterways,” he added.

Since 2020, SMC has undertaken one of the country’s largest privately funded river cleanup programs. Better Rivers PH was aligned last year with the government’s Oplan Kontra Baha, a broader flood-mitigation effort led by the Department of Public Works and Highways and the Metropolitan Manila Development Authority, together with other national agencies, local governments and the private sector.

As of August 18, Better Rivers PH had removed more than 9.387 million metric tons of silt and waste from more than 204 kilometers of waterways across Metro Manila, Bulacan and Laguna.

SMC has also expanded the program to the Visayas with the cleanup of the Butuanon River in Mandaue City, Cebu.

The latest figures and the August 17 rainfall event highlight a broader point: keeping major waterways clear can improve their ability to carry stormwater, but river cleanup alone cannot eliminate flooding when rainfall overwhelms drainage systems or garbage blocks the smaller waterways that feed into them.