Possible breach of dams eyed in Cagayan de Oro, Iligan disasters

MANILA, Philippines—Authorities are looking into the possibility that dams in Cagayan de Oro collapsed, unleashing heavy flooding on communities downstream as Tropical storm Sendong pounded Mindanao and Visayas late last week.

No less than President Benigno Aquino has asked an inter-agency task force to inquire into the possible collapse of the three mini-dams as a cause for the unprecedented massive floods in Cagayan de Oro, Science and Technology Secretary Mario Montejo said.

“There were reports in Cagayan de Oro that three dams collapsed upstream,” Montejo said at a press conference, saying it was possible debris destroyed the dam upstream that had a domino effect on the two other dams.

It was not clear though why officials would not know as of this  late hour if any or all of the three dams had collapsed.

The reports were relayed to Public Works Secretary Rogelio Singson, who in turn relayed these to Montejo, during Aquino’s visit to devastated areas in Cagayan de Oro last Tuesday where he declared a national state of calamity.

If the reports proved to be true, the collapse would jibe with survivors’ accounts about the sudden surge of floodwaters as heavy rain and gusty winds lashed Cagayan de Oro, Montejo said.

“They said it was like a tsunami, a big wave, where there was no more time to escape,’’ he said, adding:  “We were tasked by the President to investigate why it collapsed,” if reports of a collapse are true.

It was Director Renato Solidum of the Philippine Institute of Volcanology who offered the hypothesis that debris and water may have breached the first dam, forcing it to collapse, according to Montejo.

As for Iligan City, where logs hurtled downstream toward the coast and destroyed homes in their path, Montejo said the catastrophe may have been aggravated by logging .

Responding to criticisms of the weather bureau forecasting, Montejo pointed out that the same amount of rainfall hit Cagayan de Oro and Surigao del Sur, but had different outcomes because of topography.

According to Vicente Malano, Pagasa deputy administrator for operations, 180.4 millimeters of rainfall were recorded in Hinatuan, Surigao del Sur, within 24 hours, and 180.9 millimeters in Lumbia, Cagayan de Oro.

To improve flood monitoring, Pagasa would be installing 1,000 more water-level sensors in river systems throughout the country next year.

“Since the 1980s, only four rivers were installed with sensors to measure water-level rise,” Montejo said.