Angat Dam. INQUIRER FILE/GRIG C. MONTEGRANDE
CITY OF MALOLOS — Residents and local officials in at least 11 towns and cities along the Angat River in Bulacan province were alerted against possible flashfloods after Angat Dam breached its spilling level on Thursday, forcing the discharge of excess water from the reservoir.
Felicisima Mungcal, head of the Bulacan provincial disaster risk reduction and management office (PDRRMO), said incessant rains in the province raised the dam’s elevation to 213.21 meters above sea level (masl) at 8 a.m. Thursday, surpassing the 212 masl normal high-water level.
The heavy rainfall over the reservoir was due to the two low-pressure areas affecting most parts of the country, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration.
Catchbasins
Mungcal said Angat Dam officials had advised the provincial government of the water release on Thursday afternoon to ease the pressure in the reservoir.
The dam discharged water at 5 p.m. but the PDRRMO had not released any information on the volume released from the reservoir.
The low-lying villages in the towns of Hagonoy and Calumpit would usually suffer up to 4-foot high (1.21 meters) floodwater due to the overflow from the Ipo and Bustos dams that are located below Angat Dam. Both Ipo and Bustos catch the runoff from Angat.
According to the PDRRMO, the towns of Norzagaray, Angat, San Rafael, Bustos, Pulilan, Plaridel and Paombong, and the cities of Baliwag and Malolos are also expected to be hit by the floods due to Angat’s discharge. Gov. Daniel Fernando suspended classes in elementary and high schools in the province on Thursday due to the threat of floods.
Angat Dam’s elevation has been rising since October last year, with a weekly average increase of 3 to 4 masl.
According to local farmers, the rising level at Angat would provide an uninterrupted water supply for irrigation of more than 23,000 hectares of rice farms in 17 towns in Bulacan and four in Pampanga. About 97 percent of Metro Manila’s domestic water needs are derived from the dam.