Angat Dam water might dip beyond record-low elevation: PAGASA

By , on May 14, 2014

View of Angat Dam from San Lorenzo (Hilltop), Norzagaray, Bulacan.
View of Angat Dam from San Lorenzo (Hilltop), Norzagaray, Bulacan. Wikipedia photo

MANILA — State weathermen expect the water level in Metro Manila’s main water source Angat Dam in Bulacan to possibly continue lowering until August, dipping past this facility’s record-low water elevation if conditions there persist.

“Under our second forecast scenario, which assumes waterreserve-affecting conditions in Angat will continue, we estimate water level there will further dip to 176.30 meters this May, 169 m. in June, 161.60 m. in July and 154.30 m. above mean sea level (AMSL) by August this year,” said hydrologist Elmer Caringal from State-run PhilippineAtmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Data he presented Tuesday during a climate forum in Metro Manila show the projected August 2014 water level is almost 26 m. below the 180 m. AMSL critical elevation the government established for the dam.

Such projected water level is also below 157.56 m. AMSL, so far Angat’s lowest water elevation monitored in July 2010.

Caringal noted the forecast must be a wake-up call for more water conservation.

Angat’s water level breached the critical elevation this week amidst continuing dry weather and water withdrawal from the dam for domestic water supply, irrigation and power generation.

PAGASA reported that data show Angat’s water level already dipped to 179.47 m. AMSL as of 6 a.m. this Tuesday.

The data also show such water elevation is 5.76 m. lower than the 185.23 m. rule curve the National Water Resources Board set for the same day.

Rule curves are daily guides for operating dams so these facilities can meet their respective purposes.

Caringal urged caution in using water, noting conservation is key in ensuring supply of this commodity.

“We must use water responsibly and avoid wasteful practices,” he said.

Under the first scenario PAGASA earlier developed for Angat, the water level is expected at 174.77 m. AMSL this month and even lower at 167.92 m. AMSL in June.

Such scenario also forecasts a rise in Angat’s water level afterwards to 170.40 m. AMSL in July and 176.75 m. AMSL in August this year, however.

Caringal said the scenario is based on conditions in 2010 when Angat registered its lowest water level so far.

Angat’s water level by the end of May 2010 was at 174.77 m., he noted.

The country also experienced the drought-driving El Nino phenomenon that year.

In its third scenario for Angat, PAGASA forecast continuous increase in water level there to 189.10 m. AMSL this May, 194.20 m. AMSL in June and 195.80 m. AMSL in July.

PAGASA expects the water level to lower afterwards at 193.80 m. AMSL in August.

“Our third scenario is based on PAGASA’s forecast Angat basin mean rainfall,” said Caringal.

He noted that under such forecast, expected monthly rainfall in Angat basin will reach 196 mm. this May, 195 mm. in June, 467 mm. in July and 359 mm. in August.

Earlier, PAGASA senior hydrologist Max Peralta said data show 100 mm of rainfall can already raise a dam’s water level by 3.0 m.

One of Metro Manila’s private water concessionaires urged people to check their plumbing systems so leaks there can be addressed accordingly to save water.

“Please plug those leaks,” said Querubin Mojica, corporate communications chief of private water concessionaire Maynilad Water Services Inc. (MWSI).

She also urged people to call up Maynilad’s hotline 1626 to report leaks they see in the company’s water lines.