MANILA – Spilling operations in Ambuklao Dam may not resume anytime soon as it can still accommodate water from expected light rains.
In an interview, Rosalie Pagulayan, a hydrologist of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said the dam stopped spilling operations midnight Monday.
“If there’s no big weather system that can bring much rain over Ambuklao’s watershed, that dam will not yet open its gate to release excess water again,” she said.
The dam’s 6 a.m. water level on Tuesday was at 751.36 meters — just 0.64 meter below the 752 meters spilling or normal high water level there, she added.
This week, PAGASA expects the northeast monsoon (amihan) to affect Benguet where Ambuklao Dam is located.
“During the next three days, amihan can bring light rain to Benguet,” PAGASA weather forecaster Chris Perez said.
He said PAGASA has not monitored any tropical cyclones that might affect the country in the next couple of days.
Pagulayan, meanwhile, is not ruling out the possibility of Ambuklao Dam eventually resuming its spilling operation this December.
The weather bureau forecasts one to two tropical cyclones (TCs) to enter the Philippine Area of Responsibility (PAR).
Historical data indicate the possibility for some TCs to cross Luzon during December.
Rains from TCs may significantly increase the inflow of Ambuklao Dam, raising water there to a level that would already require resumption of spilling operation to preserve the facility’s structural integrity.
Ambuklao, Binga and San Roque dams comprise the series of cascading dams supporting irrigation and power generation in Luzon.
Water in Ambuklao discharges into Binga which, in turn, releases water to San Roque.
Binga Dam’s spilling operation was still in progress as of 6 a.m. Tuesday, said PAGASA.
Pagulayan noted that there is less water flowing into Binga as Ambuklao Dam already terminated its latest spilling operation.
Some runoff continues flowing into Binga, prompting Ambuklao to release water to stabilize its water level, she noted.
Binga may eventually end its spilling operation, she said.
PAGASA reported Binga’s 6 a.m. water level on Tuesday at 574.78 meters, just 0.22 meter below the normal high level. (PNA)