The operators of Angat, Pantabangan and San Roque – three major dams in Northern and Central Luzon blamed for exacerbating floods in the region last week – released water again Thurdday due to heavy rains triggered by a low pressure area, further inundating communities.

Authorities warned residents especially those along the Upper Pampanga River and Agno River in Tarlac, Bulacan, Nueva Ecija and Pangasinan about possible new floods from the dam releases, even as many areas in the affected provinces remain under water.

Chief Supt. Leon Nilo A. Dela Cruz, Central Luzon police chief and concurrent head of the Regional Disaster Coordinating Council, advised residents to take precautionary measures against the possible overflowing of rivers and tributaries near the dams.

Engineer Antonio Nangel, operations manager of the Upper Pampanga River Integrated Irrigation System (UPRIIS) which operates the Pantabangan Dam in Nueva Ecija, on Wednesday morning had advised disaster authorities, local officials and the general public that they would release water starting at 7 a.m. Thursday.

Nangel said continuous heavy rains brought by the low pressure area caused the water level of the Pantabangan Dam to rise to almost spilling level of 221 meters.

He disclosed that water level of the dam is currently at 220.45 meters.

The Pantabangan Dam released water of at least 100 cubic meters per second, according to Nangel.

Dela Cruz alerted areas that could possibly be affected by dam spilling operations like Rizal, Bongabon, Palayan City, Cabanatuan, Sta. Rosa, San Isidro, Cabiao, San Antonio, Jaen, Bayambang, all in Nueva Ecija, and some parts of Pampanga and Tarlac.

In Pampanga, the towns that could be affected by the water release are Arayat, Sta. Ana, San Luiz, Candaba, Mexico, Apalit, Macabebe, Masantol, Sasmuan, Guagua and Lubao.

Earlier, Nueva Ecija Gov. Aurelio Umali appealed to his constituents to take precautionary measures in case of emergency.

Umali said Thursday the 48-hour continuous rains and the release of water from the dam caused heavy flooding in at least 15 towns and 4 cities in the province.

In Bulacan, Engineer Alex Palada, division manager of the National Power Corporation which operates Angat Dam, said the dam released water at 100 cubic meters per second starting at 6 a.m. Thursday.

According to Palada, they alerted as early as Wednesday residents along the tributaries of Bulacan River, especially the villages of Patling and Matling in Norzagaray town, regarding the scheduled release of water from the reservoir.

Bulacan officials said floodwater continues to rise in two isolated towns as Angat Dam’s water elevation nears its critical level as of 10 a.m. yesterday, the Provincial Disaaster Coordinating Office (PDCO) said.

Jaime de Silva, a senior technician at Angat Dam in Norzagaray town, said they started releasing water to relieve the reserve from growing pressure as the water elevation exceeded the spilling level of 2:10 cubic meters.

De Silva said Angat released 100 cubic meters equivalent to 300 drums of water per second at about 6 a.m. Thursday.

"Wala naman silang dapat na ikabahala dahil napakaliit lang ng ipinapatapon naming tubig. Ang pagtaas ng antas ng tubig sa Angat Dam ay dahil sa patuloy na pag-ulan sa mga bulubunduking bahagi ng watershed area," De Silva said.

As of noon yesterday, the Bulacan Provincial Disaster Coordinating Council reported that 15 barangays in Hagonoy are still flooded. Worst hit are the villages of Palapat (3 to 4 feet), San Sebastian, San Isidro, Iba-ibayo, San Juan and San Miguel (all under 1 to 5 feet).

In Calumpit, the PDMO reported that 21 barangays are also still flooded. Worst hit are the villages of Sapang Bayan (3 to 9 feet), Gugo (2 to 7 feet), Meysulao (2 to 6 feet) and Bulusan (3 to 5 feet).

The PDMO said that based on the dam’s propagation time, the water released will reach the nearest point of Angat River in Bgy. Matictic, Norzagaray (28 kilometers away from the dam) within 2 hours and 46 minutes. It will reach the flood-stricken town of Calumpit within 9 hours and Hagonoy within 10 hours.

Hagonoy Mayor Angel Cruz and Calumpit’s De Jesus both suspended classes in all levels in their respective towns.

In Pulilan town, 400 hectares of rice fields were under 3 to 4 feet flood waters.

"Hindi na namin mapapakinabangan ang sana'y aanihin na naming palay, sirang-sira na ito, subali't nagpapasalalamat pa rin kami dahil mga bukirin lang ang binaha at hindi ang aming mga kabahayan," a group of farmers said.