MANILA – Magat Dam may soon spill or release excess water again as it nears normal high level.
Expected rain from the easterlies will likely further increase Magat’s inflow so there is growing possibility for its water to already reach the 193.00 meters normal high water level, noted Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) hydrologist Aileen Abelardo.
“That dam must spill if its water reaches the normal high,” she said.
Such spilling operation aims to help ensure integrity of the dam’s structure.
According to Abelardo, Magat Dam terminated its last spilling operation on Dec. 30, 2020 after releasing excess water due to rain from the tail-end of a frontal system and tropical depression Vicky that month.
Rainfall from the easterlies has been causing water in Magat to again rise closer to the normal high so downstream communities must already prepare for possible resumption of spilling operation there, she noted.
PAGASA reported Magat Dam’s 6 a.m. water level on Thursday at 192.10 meters or 0.47 meters higher than what it was 24 hours earlier and less than a meter below the normal high.
Magat’s water level even further rose to 192.13 meters at 8 a.m. on Thursday, PAGASA continued.
According to PAGASA, Magat received some 377 cubic meters per second (cms) of water while an average three millimeters of rain occurred during the 24-hour period ending 8 a.m. Thursday.
Abelardo noted such inflow exceeded Magat’s normal outflow of less than 200 cms at present.
“That dam has been receiving more than what it is discharging so water there continues to rise,” she said.
She expects the situation to persist, and projects between five millimeters and 15 millimeters of rainfall is possible until Friday morning (March 26) over the Magat basin.
“The expected rain can already raise Magat’s water level to the normal high,” she said.
Magat Dam fills up easily since this is a small facility that receives a lot of water from the big basin where it is located.
Last year, excess water that Magat spilled in the aftermath of Typhoon Ulysses (Vamco) contributed to the rise and overflow of water in the Philippines’ largest river — the Cagayan River.
The overflow resulted in flooding which authorities said was of a magnitude Cagayan province has not seen in decades. (PNA)