Angat still needs rain, Pagasa says
ANGAT Dam, which supplies 90 percent of Metro Manila’s raw water requirement and irrigates about 28,000 hectares of farmland in Bulacan and Pampanga, will likely remain in dire need of water due to the strengthening El Niño phenomenon.
“Angat still needs a lot of rain,” said hydrologist Richard Orendain of the Philippine Atmospheric, Geophysical and Astronomical Services Administration.
Orendain said the dam received some water from Tropical Storm “Kabayan” which left the country Friday, but even the runoff from the mountains around the dam will only raise the water level by less than one meter.
He said Kabayan helped raise Angat Dam’s water level from 190.70 meters on Friday to 192.20 meters on Saturday.
But the dam should be at its flood season, high water level (FSHWL) of 210 meters to it can have sufficient reserve for the following year, he added.
But experts have expressed fear that precipitation over Angat Dam will only be a fraction of normal levels and Bulacan, where the dam is located, is among the 10 provinces that are forecast to experience a dry spell by the end of the year.
Pagasa defines a dry spell as a condition marked by three consecutive months of below-normal rainfall while a drought officially consists of three consecutive months of way below-normal rainfall.
Latest Pagasa data also showed that Angat’s water level is only projected at 193.60 meters by the end of this month.
“Such expected water level is based on Pagasa’s forecast October 2015 rainfall of only 127.2 millimeters in the Angat watershed,” said Pagasa hydrologist Elmer Caringal.
“The expected water level is also 3.70 meters below Angat’s rule curve of 197.30 meters by October’s end,” noted Caringal, referring to the standards the government has set over the operation of dams.
Earlier, government stopped releasing irrigation water from Angat to help ensure availability of water for Metro Manila amid El Niño.
Government also reduced allocation of Angat water for Metro Manila so the dam can still have reserve for this megalopolis’ use until next year.
Pagasa expects brighter water prospects for Ambuklao, Binga and Magat dams, however.
Projections show Pagasa’s forecast 89.8 millimeters of rainfall in Ambuklao this October will raise water level there to over 752 meters by end of such month, exceeding the dam’s rule curve then.
For Binga, Pagasa’s forecast 50.6 millimeters of rain this month will cause water level there to rise beyond the facility’s rule curve of 575 meters by the end of October.
Pagasa’s forecast 76.7 millimeters of rain in the Magat area this October will raise water level there to 192.29 meters by the end of this month, exceeding then the dam’s rule curve of 188.21 meters.