MANILA — The operators of Magat Dam on Saturday warned residents near Magat River and those residing in northern Luzon of the possible flooding, as the dam released water to prevent overspilling.

The National Irrigation Administration Magat River Integrated Irrigation System (NIA-MARIIS) warned that flooding could occur in the municipalities of Gamu and Aurora in Isabela after the operators opened 2 of the dam’s spillway gates.

Operators added that water in the dam’s reservoir continued to increase at the time this story was posted, because of rainwater coming from watershed areas that recently experienced rainfall.

Earlier this month, unprecedented flooding submerged Cagayan and Isabela.

As of 3 p.m., the dam reservoir’s water level was at 189.05 meters above sea level, 4 meters short of its spilling level of 193 meters.

Magat Dam opened its first spillway gate on Friday, when it released 393 cubic meters per second (cms) of excess water, which equates to 1,965 drums of water.

Another gate was opened at 8 a.m. Saturday to release 179 cms of water, equivalent to 895 water drums.

As of 3 p.m., dam operators increased the volume of water it released to 952 cms, or equivalent to 4,760 drums of water.

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According to NIA-MARIIS’ notice of dam discharge warning operation released 5 a.m., Saturday, the spillway radial Gate 3 was already opened 1-meter wide.

The gate’s opening was increased to 2 meters at 9 a.m. to release the 393 cms excess water.

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State weather bureau PAGASA, in its 5 p.m. flood monitoring report, included the river basin of Cagayan under its flood watch, adding that flooding near the basin areas of Upper, Middle, and Lower Cagayan was possible.

“People living near the low-lying areas particularly those adjacent to and along the above-mentioned rivers are alerted against possible landslides and flash floods,” the PAGASA said.

The Magat River is a major tributary of Cagayan River.

Cagayan Governor Manuel Mamba has blamed the heavily silted Cagayan River, Typhoon Ulysses' rainfall, and water released from Magat Dam for the massive floods that submerged Cagayan, leaving at least 9 dead.

But the National Disaster Risk Reduction and Management Council said dams would break if it did not release water to prevent overtopping.

Because of this, separate resolutions have been filed before the House of Representatives and the Senate to seek investigations into the deadly flooding in Luzon. -- With reports from Harris Julio, ABS-CBN News

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