Water board hopes for heavy rains soon in Angat

MANILA, Philippines — Officials of the National Water Resources Board (NWRB) expressed hope that heavy rains would start soon in Central Luzon to replenish the dwindling water level in Angat Dam in Bulacan caused by the long dry spell.

“Only heavy rains will help improve Angat Dam’s continuously declining water level,” a board official said yesterday.

The latest monitoring of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) showed that as of 6 a.m. yesterday, the dam’s water level was down to 160.28 meters, .45 meters lower than the 160.73 meters recorded in Angat last Thursday.

“We need to have heavy rains in the Angat watershed for it to be recharged, and for its water elevation to improve,” NWRB executive director Sevillo David said.

The NWRB said if water level in Angat Dam drops below 160 meters there will be further reduction in the allocation for potable water supply to Metro Manila residents serviced by concessionaires of the Metropolitan Waterworks and Sewerage System (MWSS).

The cut in water allocation will reportedly affect 75 percent of the customer base of west zone concessionaire Maynilad and 80 percent of Manila Water’s customers in the east zone.

The absence of rain over the Angat watershed is compounded by “monsoon breaks” that PAGASA explained are a shift between weather systems, resulting in short breaks of no rainfall for several days or weeks.

He said water allocation for MWSS stays at 40 cubic meters per second (CMS). “However, we are set to enforce further decrease in water allocation for concessionaires Manila Water and Maynilad once water level in the dam drops below the 160 meter mark.”

David said when this happens, which they estimate will be today, NWRB will impose a 36 CMS allocation for Metro Manila’s water concessionaires.

At the same time, David said the Angat Dam Low Level Outlet (LLO) will be operational once the 160-meter low level mark is breached.

David said that they will put the dam on LLO mode, which involves opening the dam’s bottom channel.

He said tests have been conducted on the turbidity of the water released from the LLO and that results show water quality is “manageable,” meaning fit for treatment by the two water concessioners.

This will be undertaken while cloud-seeding operations and the re-activation of the MWSS deep wells are enforced. 

David stressed, “Water demand from consumers plays a significant role in preserving our water supply. We have been constantly appealing to the public to conserve water and we are now repeating the plea, especially when the expected rain is not yet pouring where it is needed. Saving what is coming out of the tap and harvesting rain when it comes are substantial contribution to lessen the water demand from the dam.”

Manila Water announced yesterday that the firm would implement a new scheme of rotational water service interruptions for the entire east zone of Metro Manila for an average of 12 to 17 hours.

“We are therefore constrained to implement this new rotational scheme. The additional 4 CMS reduction translates to a deficiency of 350 million liters per day (MLD) – equivalent to the consumption of almost 700,000 population per day,” said Manila Water corporate communications head Jeric Sevilla.

“We need to implement service interruptions to almost all of our customers to more equitably distribute the limited supply. What we are aiming is for all our customers to have at least several hours in a day of water in their taps to allow them to store water in the comfort of their own homes,” he added.

PAGASA meanwhile reported a brewing cyclone is expected to enter the Philippine area of responsibility this weekend and may enhance monsoon rains that could finally refill the drying Angat Dam in Luzon. 

Based on weekly weather outlook released yesterday by PAGASA, the low-pressure area, which is forecast to develop into a tropical cyclone, will enter on Sunday or Monday.

Today, partly cloudy to cloudy skies with isolated rainshowers and thunderstorms will persist over the entire country.

Josephine Salazar, regional director for Central Luzon of the National Irrigation Administration, said Bulacan farmers have to wait until the water elevation in Angat Dam reaches its minimum operating level of 180 meters before irrigation water supply could be released.

On the other hand, NWRB’s David confirmed in a text message that irrigation water allocation for Bulacan and some Pampanga farmland is approved for release when Angat Dam reaches its minimum operating water level.

Water supply from Angat Dam is prioritized for use by the MWSS once its water elevation reaches the 180-meter level. – With Jess Diaz, Paolo Romero, Romina Cabrera, Helen Flores, Ramon Efren Lazaro