3 issues that need to be addressed in Cagayan flooding

Typhoo Ulysses (Vamco) ravaged several parts of Luzon when it struck the country from November 11 to 12.

The United Nations Office for the Coordination of Humanitarian Affairs said more than 3.67 million people have been affected by the floods, with about 277,000 people displaced and at least 73 deaths as of November 19. On top of this, more than 67,000 homes have been damaged or destroyed by floodwaters and strong winds.

Cagayan, a province located in the Cagayan Valley region and the northeastern tip of Luzon, is one of the areas hit the hardest. Ulysses brought what is now known as the “worst flooding” in the region in decades, according to Cagayan Governor Manuel Mamba.

Several factors caused the flooding. Aside from being the catch basin of rainwater from Cagayan Valley and the Cordillera Administrative Region, the opening of the floodgates of the nearby Magat Dam is also seen as a cause of the massive flooding in Cagayan.

Previous tropical cyclones had also contributed to the situation. When Ulysses entered the Philippine area of responsibility, Luzon had been previously struck by 4 other typhoons – one of which was a super typhoon (Rolly).

The NIA-Magat River Integrated Irrigation System (Mariis), the operator of Magat Dam, said the successive typhoons contributed to high inflows. The Cagayan River had also reached its maximum capacity, which caused overflows. On top of this, the nearby mountain ranges became so saturated that they could no longer absorb as much rainfall as they normally could, causing rainfall to flow directly to the reservoirs.

On November 12, NIA-Mariis released water through 7 gates to prevent Magat Dam from overflowing. The gates remained open until November 13, releasing 6,244 cubic meters of water per second.

This extreme damage to the province prompted both the House of Representatives and the Senate to probe the incident separately. While House Resolution No. 1348 focused on Magat Dam, the Senate Resolution No. 570 mentioned the Ipo, Ambuklao, and Binga dams. (READ: In massive Cagayan flooding, Robredo backs probe into Magat Dam protocol)

Here are some of the key points likely to be discussed during the hearings. Check them out to get a better grasp of what happened and prepare for disasters to come.

Are the protocols for dam discharge enough?

The Magat Dam protocol says there should be a drawdown 2 to 3 days before the expected landfall of a typhoon. Concerned agencies such as the affected local government units, Office of Civil Defense, Philippine National Police, non-governmental agencies, and the media should also be informed.

NIA-Mariis maintained that they adhered to protocols by advising residents of Cagayan and Isabela about its water release to maintain safe water levels as early as November 9, or two days before Ulysses first hit land in the country. They also said the water discharge was necessary to prevent bigger damage.

However, think tank Infrawatch PH said dams, including Magat, "rushed to open gates only at the height of Ulysses,” and that the Magat Dam did not make sufficient water drawdown 2 to 3 days prior.

What can we do about deforestation, which contributed to the destruction?

Cristina Antonio, mayor of Alcala town in Cagayan, said severe flooding in the province was brought about by a "confluence of factors," including deforestation. She cited a study by Fernando Siringan, one of the country’s top river and marine geologists and former director of the UP Marine Science Institute, about flood and riverbank erosion on the Cagayan and Pared rivers in Alcala.

The study, which was conducted from July to September 2020, said native trees that normally retained soil and regulated water release were stripped from mountains, slopes, and watersheds in the entire Cagayan Valley. The trees are being cut and forests are being threatened, not only by illegal logging, but also by yellow corn farming and the use of herbicide that kills vegetation and weakens the soil.

For his part, Mamba said there needs to be an inter-regional approach in addressing environmental problems. He said the massive flooding in Cagayan is a showcase of environmental neglect, mainly spurred by the degradation of forests.

What can we do in the future to prevent similar disasters?

One of the common goals of both the Senate and House investigations is to come up with measures and a comprehensive strategy to prevent similar tragedies in the future. Part of this is identifying the infrastructure needed to prevent or lessen the damage brought by natural disasters.

"We must anticipate that the dams will release water, so there should have been infrastructure in place into which the water would flow and gather, so that it does not inundate and devastate communities,” Senator Ramon Revilla Jr, principal author of the Senate resolution, earlier said.

A study by global management consulting firm McKinsey & Company said that by 2050, Asia could see worse effects of climate change compared to countries in other parts of the world. The study said that more than 75% of the global capital stock, a measure of impact on physical assets and infrastructure, that could be damaged from riverine flooding in a given year, is in Asia.

“Climate science tells us that, absent adaptation and mitigation, the climate hazards the region faces in the future, from heat waves to flooding, are likely to be more severe, more intense, or both,” the report said, which is part of the company’s ongoing series about the future of Asia.

Despite this, the study also said that Asia is “well-positioned” to address the challenges of climate hazards if countries invest well in infrastructure. Countries in Asia will need to ensure that climate risk is incorporated in policymakers’ capital and urban planning decisions, the study said. – Rappler.com

Pauline Macaraeg

Pauline Macaraeg is part of the Rappler Research Team’s fact-checking unit. Aside from debunking dubious claims, she also enjoys crunching data and writing stories about the economy, environment, and media democracy.