DATA GAPS, FLOOD TRAPS: Iloilo City’s flood woes worsened by poor data, resource gaps

By Rjay Zuriaga Castor

The Iloilo City Council’s probe into worsening flood issues revealed that the lack of updated topographic maps and comprehensive data is hampering the evaluation of flood control projects and long-term mitigation efforts.

During a recent committee hearing, Darwin Joemil Papa, head of the Quick Response Division of the Iloilo City Disaster Risk Reduction and Management Office, said existing flood hazard maps rely largely on elevation and proximity to waterways but do not reflect the full extent of flood risks.

He said the city still uses a topographic map from the 1950s as the basis for analysis, despite rapid urban development in recent decades.

Papa explained that while the Department of Environment and Natural Resources–Mines and Geosciences Bureau has produced national flood hazard maps and Climate and Disaster Risk Assessment (CDRA) tools, they are not sufficient to capture localized changes.

He emphasized that the current maps do not fully account for Iloilo City’s altered terrain and changing water flow caused by urbanization.

“Almost the whole City of Iloilo is at high risk of flooding,” he said.

“We only have a few tracts that are not covered by a high risk of flooding,” he added.

Papa also noted that flooding during recent storms occurred even in areas classified as low-susceptibility zones, while some flood-prone barangays remained unaffected.

He said the city is now digitizing available maps to overlay flood hazard data for improved planning.

He clarified that being classified as high-risk in the CDRA does not always mean an area will flood, but that it often contains vulnerable populations such as informal settlers.

Vice Mayor Lady Julie Grace Baronda said the absence of official and updated maps on waterways and flood control infrastructure prevents the city from assessing whether past projects have worked or where new ones are needed.

Councilor Rex Marcus Sarabia echoed the concern, stressing the urgent need for complete and current data to formulate effective, localized flood solutions.

“I also would like to manifest that we have incomplete data right now,” Sarabia said.

“We have to admit that we need to have further study,” he added.

He noted that old maps can no longer be relied on, as the natural course of water has changed over time.

He added that solutions will fail without accurate, digitized data.

“This [flooding] is a continuing problem of the city,” Sarabia said. “What is clear from the data that we have is that the problem of flooding is collective.”

He acknowledged the difficulty of tracing waterway paths due to their evolving nature.

“Our data, we admit, needs to be digitized,” he said. “We will have a hard time tracking waterways because they change over time.”

Sarabia said that while drones are now used to scan Iloilo’s terrain, more funding is needed to support advanced flood mapping.