Water supply worsens in Metro Manila, Central Luzon

CITY OF MALOLOS, Philippines, July 13 ------ While 17 people died with 10 more missing in Mindanao because of Supertyphoon Inday (international name: Bavi), more than 15 million residents of the Metro Manila area and more than 22,000 farmers in Pampanga and Bulacan continue to pray for rain.

Angat Dam’s water level fell further to 156.07 meters above sea level (masl) on Saturday, with local officials saying only heavy rains from a typhoon crossing the Sierra Madre mountain range — not the southwest monsoon or “habagat” — can replenish the country’s main reservoir.

The reservoir stood at 156.09 meters above sea level (masl) at 6 a.m. before dipping further to 156.02 masl by 1 p.m., based on records from the Bulacan Provincial Disaster Risk Reduction and Management Office (PDRRMO). The latest reading came after the reservoir breached its previous record low despite rains brought by Inday and the habagat.

Angat Dam is located in the mountainous hilltop area of Barangay San Lorenzo in Norzagaray town, within the Angat Watershed Forest Reserve in the Sierra Madre mountain range. Manuel Lukban Jr., head of the Bulacan PDRRMO, said the dam’s water level remained virtually unchanged because the recent rains fell over lowland areas and did not favor the Sierra Madre watershed whose runoff feeds the reservoir.

Historic low

“It is almost the same because these are habagat rains, not rains coming from the mountains. The dam’s elevation will increase more easily if a typhoon directly hits the Sierra Madre,” Lukban told the Inquirer. The reservoir measured 156.39 masl on Friday. On Thursday, Angat Dam fell below its previous historic low, reaching 156.69 masl at 6 a.m. before declining further to 156.66 masl at 11 a.m., from 156.68 masl at 8 a.m.

The current level has surpassed the previous record low of 157.56 masl, recorded in July 2010 during a severe El Niño episode that devastated rice production, particularly in Central Luzon. Raul Agustin, a senior PDRRMO officer, recalled that then Agriculture Secretary Arthur Yap ordered a series of cloud-seeding operations over the Angat watershed to help replenish the reservoir during the 2010 drought, but agricultural officials are not very optimistic about the impact of such operations.

Due to the critically low water levels, the National Water Resources Board has reduced water allocations for Metro Manila and halted irrigation supply to farms in Bulacan and Pampanga. Lukban said the current water level is the lowest he has seen in nearly six years as head of the provincial disaster management office.

The mean annual rainfall in the Philippines varies significantly by region but ranges from 965 mm to 4,064 mm every year. Metro Manila’s water suppliers have assured their customers that they have identified alternative sources of water, but the impact will likely have a more serious effect on farmers, especially in Central Luzon, which serves as Metro Manila’s “rice bowl.”

The National Irrigation Administration (NIA) has completely suspended irrigation water releases to approximately 27,000 hectares of rice fields served by the Angat-Maasim River Irrigation System. Normally, the wet season planting begins around July 15, but NIA officials have confirmed that irrigation supply will likely be delayed until August at the earliest. Until the dam reaches at least 185 meters, farmers can only expect a negligible 10 cubic meters, which is insufficient for rice cultivation.

In its 5 p.m. weather advisory on Saturday, the Philippine Atmospheric, Geophysical and Astronomical Services Administration reported that monsoon rains are forecast to affect Zambales, Bataan and Occidental Mindoro. Occasional rains, caused by the southwest monsoon, may affect Metro Manila and the southern Tagalog region, Western Visayas, Negros Island Region, Ilocos Region, and Central Luzon.

Source: inquirer.net