For over 40 years, the Angat Dam has been supplying potable water to Metro Manila, but is it still stable enough to withstand strong earthquakes?
The government has set aside at least P50 million to find this out, dam officials said.
Rodolfo German, general manager of the Angat River Hydro Electric Power Plant (Arhepp) of the National Power Corp. (Napocor), said the study and testing of the facility would take six months after the awarding of the contract to the winning bidder.
Among the companies interested in undertaking the project are New Zealand-based Tonkin & Taylor and its local partner, the Engineering and Development Corp. of the Philippines (Edcop), he said.
Earlier, Bulacan Governor Wilhelmino Sy-Alvarado asked national officials to check the structural soundness of the Angat Dam and if it could stand earthquakes hitting nearby Metro Manila, where a major fault system lies.
Towns and low-lying villages along the more than 50-kilometer stretch of the Angat River are at risk if the dam is damaged and bursts, Sy-Alvarado said. These areas experience heavy floods whenever excess water is released from the dam, especially during typhoons.
The study would help ease the worries and fears of local officials and residents, especially in Norzagaray, Angat, San Rafael, Baliuag, Bustos, Plaridel, Pulilan, Calumpit, Hagonoy and Paombong towns, German said.
The Angat Dam and its facilities were built from 1964 to 1967. The dam started operations in 1968, and has since been providing 97 percent of the water supply of Metro Manila households, businesses and industries.
Its reservoir supplies irrigation water to about 31,000 hectares of farmlands in Bulacan and Pampanga.
The Angat Dam generates 246 megawatts of electricity for the Luzon power grid.
It also acts as flood control facility as it catches heavy inflow of water from the Sierra Madre mountains during heavy rains and regulates the release of water to spare low-lying communities from heavy floods, according to Saturnino Espiritu, dam safety engineer.
In an earlier meeting with local officials, Dr. Renato Solidum, director of the Philippine Institute of Volcanology and Seismology, acknowledged the need to fully determine the stability of the Angat Dam.
A section of the Marikina Valley fault system (MVFS) is connected to the Sierra Madre mountain range, where the Angat reservoir is located, he said. The MVFS western line starts from Laguna and runs toward the Sierra Madre.
“There is no danger if the dam is sturdy. There is no cause for worry. But we have to study the dam’s stability. We should prepare because if the West Valley Point moves and there is strong ground shaking, we could expect a 7.2 magnitude earthquake,” Solidum told Bulacan officials.
But he asked the officials to prepare for a worst-case scenario for extreme flooding and draw up a preparedness plan in case the dam is damaged by a strong earthquake.
Froilan Tampinco, Napocor president and chief executive officer, earlier told reporters that Napocor would hire foreign dam experts and engineers to check the Angat Dam.