Repair aging dams in Bulacan

MALOLOS CITY—Bulacan Governor Wilhelmino Alvarado called for immediate repair of ageing dams in Bulacan as the government prepare to opening bidding for the rehabilitation of the giant Angat Dam next month.

As this developed, the National Power Corporation (Napocor) reiterated that Angat Dam is strong and can withstand magnitude 7.2 earthquake.

In his weekly program aired over DWSS Radio, Alvarado said that rubber gates at Bustos Dam are old and needs to be replaced.

“I will raise that concern in our next RDC meeting,” he said referring to the Central Luzon Regional Development Council (RDC) chaired by Mayor Oscar Rodriguez of the City of San Fernando in Pampanga.

Alvarado said that they will ask officials of the National Irrigation Administration (NIA) to present current status of the dam located along the Angat River in between the towns of Bustos and San Rafael, Bulacan.

NIA operates and manages Bustos Dam to distribute water for irrigation needs of Bulacan and Pampanga farmers.

Earlier, Engineer Felix Robles said that fishing, dipping and swimming on the  apron of Bustos Dam is no longer allowed.

The warning came after he disclosed that rubber gates of the dam is nearing the end of its lifespan.

As an officer in charge of NIA’s Water Control and Coordinating Unit (WCCU), Robles recounted that a similar rubber gate of a dam in Florida in the United States burst recently leading to rapid outflow of water from the reservoir.

“The lifespan of a rubber gate is 14 to 15 years, and it could be shorter like the one in Florida defending on the weather condition,” he said noting that rubber gates installed at Bustos Dam is as old as the one that burst in Florida.

Since rubber gates of Bustos Dam are nearing the end of its lifespan, Robles said they cannot ascertain its safety, and must be replaced immediately.

He advised local residents to stop fishing on the dam’s apron, while warning local tourists from dipping and swimming at the downstream of the dam.

“Its can burst anytime, and when deflated, water will rush downstream to the apron,” he said and added that every year they conduct repair on the cracks on the rubber gate by vulcanizing it.

Meanwhile, Engineer Rodolfo German of the Angat River Hydro Electric Power Plant of the Napocor said that bidding to rehabilitate Angat Dam is set to proceed next month.

But he also commented on news reports that Angat Dam have cracks.

“That’s impossible, Angat dam dykes are not concrete. They are rock and earth-filled with earthen core,” said German.

He reiterated that there is no crack on the dam structures noting that as a rock and earth-filled dam, it naturally heals in case of earth movement caused by earthquakes.

German added that dam structures were built to stand a magnitude 7.2 earthquake.

With regards to siltation on dam’s reservoir, he said that Angat Dam will last for another 60 years.

At present the dam is already 43 years old and another 60 years means that it will last for 100 years.

According to German, the power tunnel of the dam is 50 meter above the bedrock of the dam.

“It will take another 60 years before it will be covered by silt,” he said.

German said that silt on the dam’s bedrock accumulates at an average of half meter every year.

At present, he estimated that there is about 20 meters deep silt on top of the dam’s reservoir bedrock.  (Dino Balabo)