NARVACAN, Ilocos Sur — Prolonged heavy rains, rising river levels and strong currents contributed to the collapse of a portion of the flood control structure at the ongoing Nangueg West Bridge project, according to sources within the Department of Public Works and Highways (DPWH).

The bridge remains under construction and had not yet been opened for regular use when the damage occurred.

DPWH sources said a temporary access road made of compacted earth beneath the bridge was being used by people and vehicles while construction continued.

Days of continuous heavy rainfall caused the river to rise and washed away about 20 meters of the temporary access road.

The washout altered the water flow, directing stronger currents toward the flood control structure. Instead of dispersing across a wider area, the water exerted greater hydraulic pressure on the affected section.

With heavy rains and strong currents persisting for several days, the structure was repeatedly exposed to the force of the rising river, eventually affecting the foundation and causing a portion of the slope protection or revetment structure to collapse, the sources said.

The DPWH sources cautioned against immediately attributing the incident to construction defects or poor workmanship. They said the project was being implemented according to approved plans and specifications, while construction materials had undergone required testing.

The contractor, Satrap Construction Co. Inc., also cited heavy rainfall and water conditions in a letter dated 10 August 2026, addressed to Ilocos Sur 2nd District Engineer Neil C. Farala through Project Engineer Janice C. del Rosario.

The letter covered Project 25APA0047, or the SIPAG project for the replacement of Nanguneg West Bridge in Narvacan, Ilocos Sur.

Satrap said its investigation found that the collapsed slope protection or revetment was critically damaged by strong water currents brought by heavy rains and Typhoon “Maymay.”

The contractor said continuous rainfall over several weeks caused the river level to rise, with the strong current and increased water level believed to have caused the affected portion to slip and collapse.

Satrap committed to undertaking repair and rectification works under its contractual obligations. The proposed measures include reconstructing the collapsed revetment and assessing the existing foundation to restore structural integrity and address forces that could affect adjacent structures.

The contractor also committed to documenting the remedial work through photographs.

The incident has raised questions about the condition of the structure, particularly since the bridge was still under construction.