THE collapse of a 15-meter portion of the Butuanon River flood control project in Barangay Casuntingan, Mandaue City was triggered by floodwaters diverted behind the structure through a temporary access road.
Assistant District Engineer Eda de Guzman explained during a press conference on Wednesday, August 20, 2025, that the diverted flow from the heavy rains last week weakened the section, causing it to give way.
District engineers emphasized that the riprap was built according to standards and based on the approved structural design for flood control.
Planning and Design Engineer Romar Jude Yan noted that while the structure may have looked “thin” above ground, it was in fact reinforced with proper foundations and reinforcements, including stone masonry, lean concrete, and steel sheet piles driven nine meters deep with one meter exposed above ground.
The project design also provided for a minimum one-meter freeboard above the design flood level and a four-meter-wide temporary access road, elevated 0.7 meters, to facilitate construction.
However, engineers acknowledged that the access road unintentionally redirected floodwaters toward the back of the riprap, which contributed to the collapse during the unusually strong downpour.
Last week’s rains caused the Butuanon River to overflow, sweeping away several houses in Sitio Lub-ang, Barangay Casuntingan.
Residents have pointed to unfinished sections of the project as one reason the floodwaters breached their homes.
Sixth District Representative Emmarie “Lolypop” Ouano-Dizon, who inspected the site immediately after the incident, pressed Department of Public Works and Highways (DPWH) engineers to explain the cause of the failure and ensure that corrective measures will be implemented.
The DPWH said it is conducting further assessment of the collapsed portion and will recommend the necessary repairs to restore and reinforce the structure.
Meanwhile, residents living near the riverbanks have been urged to remain vigilant as the rainy season continues. (CAV)