MANILA – The Magat Dam in Northern Luzon may continue spilling excess water for the whole of December.
In an interview Thursday, Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) hydrologist Richard Orendain said this is to prevent the dam from reaching a dangerous water level that may cause structural damage.
This came as rains brought by various weather systems continue to increase the dam’s water level.
“This month, Magat may not yet close its gate to stop releasing water,” he said.
For December this year, PAGASA forecasts around 240 millimeters of rain in the basin where Magat Dam is.
“That’s a lot of rain,” he said.
Tropical cyclones (TCs), northeast monsoon or ‘amihan’, and other weather systems can bring such rain, he noted.
Above-normal rainfall is possible this December in Northern Luzon and other parts of the country, PAGASA also said.
The successive onslaught of TCs since October this year helped raise the water level in Magat Dam.
The release of Magat’s excess water contributed to flooding that ravaged areas in Cagayan Valley in November.
PAGASA reported Magat’s 6 a.m. water level at 189.09 meters on Thursday, just 3.91 meters below the 193 meters spilling or normal high water level of this facility.
Orendain noted Magat fills up easily since it’s a small dam in a large basin.
The dam receives a lot of the basin’s runoff, he noted.
According to PAGASA hydrologist Sheila Schneider, Magat Dam last opened its gate on Nov. 9 this year to release excess water in preparation for the onslaught of Typhoon Ulysses.
Magat Dam hasn’t yet stopped releasing water since then, she noted.
PAGASA said Magat Dam’s spilling operation is still in progress as of 6 a.m. Thursday, with one gate open at a height of 1.00 meter to release excess water.
However, the dam was releasing more excess water 24 hours earlier with one gate open at a height of 2.00 meters.
“Even if Magat closes the gate, there is a big chance such dam will reopen it this month to resume releasing water,” Orendain said.
He earlier forecast Magat to be operating at full capacity by the end of December.