ANGAT DAM is seen to hit the critical water level of 160 meters by this weekend, with east zone concessionaire Manila Water Company, Inc. (MWC) warning its customers of more service interruptions.

The National Water Resources Board (NWRB) said as of 6 a.m. on Monday, the water level at Angat Dam declined to 162.39 meters, 17.61 meters below the minimum operating level of 180 meters.

In a press briefing in Quezon City, NWRB Executive Director Sevillo D. David, Jr. said if there are no heavy rains soon, the water level at Angat Dam may fall to a new low.

“We are hoping na dumating ang pag-ulan at ‘di dumating sa ganung level. (We are hoping that rain will come and it won’t get to that level.) But we will see in the next couple of days until next week,” Mr. David said.

Water elevation at Angat Dam last dropped below the critical level of 160 meters on July 13, 2010 when it registered a low of 157.57 meters, as the El Niño phenomenon affected the country.

“Kailangan natin ma-manage yung supply until such time na umabot yung pag-ulan talaga sa watershed (We need to manage the supply until such time that rain will come to the watershed,)” Mr. David said.

MWC President and Chief Executive Officer Ferdinand M. Dela Cruz said noted that its service will be affected as the Angat Dam’s level goes gown and water releases to concessionaires are reduced.

“There will be rotational interruptions, but it doesn’t mean na walang tubig (there is no water). We will try to make sure that the reservoirs are still filled up,” Mr. Dela Cruz said in a briefing in Mandaluyong on Monday.

For the east zone, MWC said water availability for at least eight hours at the ground floor is at 99.7%. Meanwhile, its 24-hour availability at least at the ground floor is at “a little over 90%” of its water service connections as of Sunday.

Mr. Dela Cruz said Angat Dam’s water level should be at 212-215 meters for it to comfortably service its customers.

The company has benefited from its supply augmentation efforts despite the lower levels at Angat Dam. This includes supply from its Cardona treatment plant which delivers almost 60 million liters per day (MLD), deep wells that provide 47 MLD, and cross border flows from west zone concessionaire Maynilad Water Services, Inc. at 20 MLD.

“We’ve been successful in augmenting the supply that we could control…so we’re about 107 MLD on the things we could control,” Mr. Dela Cruz said, adding that the Cardona plant will reach 100 MLD by August.

Mr. Dela Cruz said that while the Philippine Atmospheric, Geophysical and Astronomical Services Administration already declared the official start of the rainy season last week, water level at Angat Dam continues to go down since rains are not strong enough to bring it back to its normal level.

Mr. Dela Cruz however said that Angat Hydropower Corp. has assured them that even if the critical level is hit, they can continue operating until the dam hits 150 meters through a combination of low level outlet and bypass, which are other ways of drawing water from the dam.

“The caveat there, the lowest operating point we’ve done is 157. We’ve never crossed lower. This is new territory for us. What we’re saying is we’re happy that there is contingency — that’s still 10 meters,” Mr. Dela Cruz said.

NWRB’s Mr. David said the dam’s low level outlet, which was last used in July 2010, is now being tested. He said according to the tests, water quality coming from the low level outlet is “manageable.”

MWC said it will continue to monitor the volume and water quality when the dam reaches its critical level. — Arra B. Francia and Katrina T. Mina

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