To raise the already-critical water level at Angat Dam, which is Metro Manila’s main water source, the Philippines will need more storms to dump rain into the reservoir, the state weather bureau said Wednesday.
The dam will get that much-needed liquid from about 9 to 13 tropical cyclones that are forecast to enter the Philippine Area of Responsibility in the next six months, despite the persistent drought affecting 32 provinces across the country.
READ: ‘Dodong’ manna from heaven amid water crisis
Storms supply about half of the water being used for domestic requirements, especially in the National Capital Region, officials of the Philippine Atmospheric, Geophysical and Astronomical Services Administration said in a press conference.
In other developments:
• Tropical Depression “Dodong” sped up to 30 kilometers per hour while moving northward Wednesday afternoon, the weather bureau said.
Ariel Rojas, PAGASA forecaster, said “Dodong” was forecast to exit the PAR on Wednesday night.
• Metro Manila’s water concessionaires have submitted a “notice of force majeure” to the Metropolitan Waterworks and Sewerage System amid the worsening water shortage in the big city.
MWSS chief regulator Patrick Ty said the “force majeure” reason was filed by Manila Water Co. Inc. and Maynilad Water Services Inc. to explain the water troubles being felt in the metropolis amid Angat Dam’s declining water level.
PAGASA Hydrologist Sonia Serrano said the current water level of Angat Dam—which supplies 96 percent of Metro Manila’s water—is near the lowest ever mark of 157.56 meters, recorded in 2010.
National Water Resources Board Executive Director Sevillo David Jr. told radio DZMM that if the drought continues, “we estimate that before the weekends, we will breach the record-low registered in 2010.”
To normalize its water level, Angat Dam will need more than 300mm of rainfall, Serrano explained. For comparison, Metro Manila experiences about 140mm of rainfall on average every August, which sees rain for 22 days.
“We want to reach 180 meters which is the normal operating level of Angat Dam. That will need about 365mm of rainfall,” she noted.
PAGASA noted that more areas in the country may expect near normal rainfall in the coming months, especially in drought-hit regions such as MIMAROPA, Western Visayas, and the Zamboanga Peninsula.
The effects of El Niño is expected to affect the country until this August, but the weather phenomenon itself is likely to persist until the first quarter of 2020, the weather bureau added.
Still, the agency is confident that Angat Dam’s operating level will improve in the next two months. It currently is at 158.4 meters, just 0.8 meters above the record low in 2010.
Serrano also said Angat Dam’s reserve record low was marked at 162.74 meters in 2014.
“We may not get a sudden rise in [water level] except when tropical cyclones make landfall and drop continuous heavy rainfall directly to Angat Dam,” explained Esperanza Cayanan, PAGASA Weather Services chief.
Meanwhile, the water level at La Mesa Dam, which Manila Water also draws from for its requirements, is at 70 meters. PAGASA is concerned, however, that impurities may affect the quality of water to be released into the NCR because La Mesa Dam’s intake has not been used for a long time.
“The impounded water is already muddy,” said PAGASA hydrologist Roy Badilla. So the issue or the main concern is that, when they decide to open the dam intake, all sand and mud will flow with the water. It will affect the quality of water supply in Metro Manila.”
