The National Water Resources Board (NWRB) will lower water supply for Metro Manila starting Saturday in light of the decreasing water level in Angat Dam.

As of Friday, Angat Dam remained at the highly critical level of 158.66 meters, which was 22.69 meters short of its normal operating level. It was the dam’s lowest recorded level since 1998.

The authorities pointed out that the rains over the watershed have been insufficient to replenish the water inflow to the reservoir.

Engr. Jorge Estioko, chief water resources development officer of the NWRB, said they will be implementing lower water allocation starting Saturday “to ensure that Metro Manila’s domestic water supply will be maintained.”

From 33 cubic meters per second (cms.), the water allocation for Metro Manila starting Saturday will be cut to 32 cms.

The present allocation for domestic water supply in Metro Manila is about 30 percent lower than the normal allocation of 46 cms.

Estioko said Maynilad and Manila Water consumers will likely experience lower water pressure or shortened hours of water supply due to the cut in water allocation.

At present, Angat Dam supplies domestic water to Metro Manila, using a low-level water outlet, which is capable of operating below a 160-meter water level, going directly to Bulacan’s Ipo Dam and further down to La Mesa Dam in Quezon City.

Angat Plant management suspended the operations of its turbines for repair and maintenance last July 7.

It decided to implement a three-day suspension of operations when the water level in Angat Dam reached the 159-meter mark last Sunday.

Estioko explained that the Angat Plant management may further defer the operation of Angat Dam’s turbines to prevent the machine from breaking down because the efficient level for the turbine to operate should be more than the 160-meter water level.

“Water inflow is only 20 percent of our normal historical inflow. If the turbine could not still be used, we will continue to use the low level outlet of Angat Dam to supply the domestic water needs of Metro Manila residents,” he pointed out.

“The water situation in Metro Manila remains tight, but there is no water crisis yet. The water level in Angat Dam may have reached the critical level, but the supply of water is still manageable to meet the domestic requirements of Metro Manila’s population of 15 million,” Department of Environment and Natural Resources (DENR) Secretary Ramon Paje said in a statement.

“The supply of water for the Metropolitan Waterworks and Sewerage System (MWSS) is assured through the utilization of low level outlets of the reservoir,” Paje said.

During the 1997-98 El Niño there was a reduction of water supply to Metro Manila from 37 cms to 22 cms, resulting to water rationing as the available water was reduced to four hours per day.

About 30 percent of the population of Metro Manila who have no access to water coming from MWSS relied on private operators, which offered water at a higher cost.