NIA: If Magat Dam did not release water, it would break, millions would be affected

National Irrigation Administration Administrator Ricardo Visaya on Monday said the gates of Magat Dam had to be opened since last week amid heavy rains from Typhoon Ulysses to prevent the dam from breaking and causing a bigger catastrophe.

"Ang laki ng ating reservoir ng Magat [Dam] is about 4,800 hectares. 'Pag ito ang na-break, lumampas sa spilling level na 193 meters above mean sea level, mag-spill po 'yan. Masisira po 'yan at milyon-milyon po na tao ang maaapektuhan," Visaya said in an interview on GMA's Unang Hirit.

The NIA chief was reacting to criticisms that the dam's release of water caused widespread flooding in Cagayan and Isabela since late last week.

Magat Dam had seven gates open at one point on Nov. 12 and released water volume equivalent to 106.223 Olympic-sized swimming pools, or around two swimming pools per second.

"Meron tayo mine-maintain na safety level. It should be below 193 meters above mean sea level. Kung ano dapat ang inflow should also be the outflow," Visaya said.

The NIA official said the Magat Dam reservoir was receiving water from eight water tributaries coming from Ifugao and Nueva Vizcaya, so even if Ulysses did not directly hit the Magat Dam area, water continuously poured into the reservoir.

"Ang Magat reservoir natin doon pumupunta ang walong tributaries. Doon sa Ifugao, mga tatlong rivers, atsaka Nueva Vizcaya, lima 'yan. Hindi natin ma-control 'yan. Kaya inu-unti-unti natin 'yung pagpapalabas ng tubig," Visaya said.

"However, noong November 12, hindi nag-landfall 'yan sa Isabela ang Ulysses, but ang daming tubig na pumapasok sa Magat Dam. So anong gagawin natin diyan? So sinusunod natin 'yung protocol," he said.

Visaya said as per protocol, NIA will await the advisory from PAGASA before the dam releases water.

"Hindi kami makapagpalabas without the advice ng PAGASA. Actually, sa mga pre-releases, na-advisan kami ng PAGASA na nasa preemptive stage na at kailangan nang magpakawala," he added.

Announcement

Visaya however said they announced the impending release of water from the dam before Magat Dam's gates were opened.

"Bago ma-release naman niyan, lahat ng medium of dissemination, gaya ng radio, even email, telepono, siren sa mga malalapit na lugar ay ginagamit para maimpormahan lahat ng tao," he said.

"Ang pagre-release ng tubig, kung anong amount 'yan, diyan sinasabi lahat sa notice. At ang pinaka-minimum na oras para mabigyan ang mga tao na nakatira sa along sa mga riverways o sa irrigation canals namin ay mga minimum of six hours," Visaya added.

He added that they also course their announcement through the Provincial Disaster Risk Reduction and Management Offices concerned.

"Ang ating dam division sa Magat Dam ay lahat ng mga mediums for dissemination ay ginagamit. Hindi po namin kaya na bawat bahay. Kaya dini-disseminate natin sa PDRRMC na magpupunta po lahat sa mga kabahayan. Sila mismo ang pumupunta sa mga kabahayan. Local government na 'yon" Visaya said.

Isabela and Cagayan have been placed under state of calamity as massive flooding submerged houses, and residents had to seek shelter on rooftops.

Cagayan

Visaya said Cagayan's situation is "very complex."

"Ito sa Cagayan, it's a very complex situation dahil meron tayong 20 river tributaries diyan at isa lang ang Magat Dam. Palaging nabe-blame ang Magat Dam. 'Yung ating Magat River Irrigation System ang mayroong gadgets at instruments na nagbibigay ng data. All other 19 rivers na 'yan na galing sa Mt. Province, Kalinga, Ifugao, Nueva Vizcaya, ang dami niyan, walang ano 'yan, hindi natin name-measure 'yan," he said.

Visaya also said the Cagayan River is already heavily silted.

"Nakikita natin na 'yung Cagayan River ay heavily silted na. Makita niyo, 'yung tubig na lumalabas diyan, brown na," he said.

"Low-lying talaga kasi 'yan. Catch basin talaga ang Cagayan," Visaya added.

Lawsuit, investigation

The local government of Tuguegarao City in Cagayan is mulling filing charges against NIA for the release of water from Magat Dam which caused the flooding.

Asked for comment, Visaya said: "No problem. Naiintindihan po natin 'yan. Sasagutin natin 'yan."

Vice President Leni Robredo on Monday expressed support to any investigation on dam authorities regarding the simultaneous opening of gates amid Typhoon Ulysses, which is blamed for the massive flooding that hit many areas in Luzon.

After authorities in Marikina and Cagayan threatened to sue the Angat and Magat Dams for causing widespread flooding in their localities, President Rodrigo Duterte on Sunday said the release of water from dams is necessary to avoid “catastrophe.”

“It’s a dam, you have to release it. Otherwise, you’ll have a catastrophe,” he said in a briefing in Camarines Sur.

NDRRMC

On the suggestion to have the National Disaster Risk Reduction and Management Council be the one to decide whether dams would release water, Visaya said this has to be studied.

"Ito ay pag-aaralan natin 'yan kasi ito ang mga localized situation. Kailangan mabilis ang decision making nito. Dapat kung sino dapat ang nakakakita doon, siyang ano talaga diyan. We have to guide them," he said.

Visaya said he will discuss the matter with Interior Secretary Eduardo Año.

The NDRRMC said as of Monday, the number of fatalities due to Typhoon Ulysses remained at 67 while 21 individuals were wounded and 13 are still missing.

Ten were killed in Cagayan while one remains missing. At least three persons died and two were missing as of Sunday in Isabela, the local government said.

A total of 2,074,301 individuals or 523,871 families have been affected by the strong typhoon that hit several areas on Thursday, the NDRRMC said.

Ulysses left the Philippine Area of Responsibility on Friday morning. —KG, GMA News