Repeat of heavy flooding threatens Pangasinan as rivers remain silted
4 YEARS AFTER ‘PEPENG’
EVERY TIME it rains hard for days in Pangasinan province, Board Member Danilo Uy would grab his mobile phone and send a text message to Tom Valdez, vice president for corporate social responsibility of San Roque Power Corp. in San Manuel town.
Uy wants to know the reservoir’s water level and how much water is flowing in and out of the dam. He wants to make sure that he always gets the latest figures so that he can pass it on to his constituents.
Like most residents of his district, which consists of nine eastern towns and Urdaneta City, Uy had been so traumatized by the massive flooding that devastated the province in October 2009 that a prolonged rainfall is enough to make them worry.
“That was how the big flood began. It rained for days,” Uy says. “Now, we should be informed so that we will know how to prepare. That’s why we have to always monitor the dam.”
Uy’s district is traversed by three major river systems: the Agno, Bued and Tagamusing rivers, which all originate from different parts of the Cordillera mountains.
It is the Agno River he watches closely because it is where the San Roque Dam was built. The dam’s water releases were largely blamed for submerging 973 villages in 39 towns and cities of the province four years ago, killing 62 people and destroying P7.3 billion worth of infrastructure, crops and fishery.
Dam officials had pointed to the incessant torrential rains that Typhoon “Pepeng” dumped into the Agno River basin for filling the facility to the brim.
“We all know that the rainfall at that time was unprecedented. According to Pagasa (Philippine Atmospheric, Geophysical and Astronomical Services Administration), the amount of rain that should have fallen for two months fell in just two days,” Valdez says.
When Pepeng began dumping rains, the dam’s water level was 280 meters above sea level (masl). By the time the rains stopped, the reservoir had collected an additional 720 million cubicmeters of water.
The dam operator had no choice but to open all its spillway gates, releasing water of up to 5,072 cubic meters per second (cms), more than enough to overtop and breach dikes along the Agno River and inundate to record level the communities on its banks.
No match
Provincial administrator Rafael Baraan says the provincial government’s disaster response teams were no match to the intensity and magnitude of the flood.
The province was so prepared at that time that even before dam officials could announce that they were spilling water, Gov. Amado Espino Jr. had already ordered an evacuation of residents in low-lying communities, Baraan says.
But when the floodwaters began submerging houses and sent people climbing to the roofs of their houses, the disaster response teams were overwhelmed.
“There are situations when we are not capable of coping simply because of the immensity of the event,” Baraan says. “In fact, the US Navy came to help us. But even the US Navy guys waited for a good time to go near the shore because the current going out of the Agno River [to the Lingayen Gulf] was really very strong and they could not just come here.”
Four years after the catastrophe, provincial officials can only wish the massive flooding will not happen again.
Wrong decision
Looking back, Uy says that had the operator of the San Roque Dam not committed a mistake of releasing water late, the disaster would have been averted. “The water release was too sudden and the volume was big,” he says.
A committee created by then Energy Secretary Angelo Reyes found after a three-month inquiry that the dam operator had made the wrong decision by not conducting preemptive releases.
“Preemptive spillway releases [of 2,000 cms or more] should have been taken when the situation in the dam was already ‘flood period’ or beyond the ‘precautionary’ or ‘caution’ periods since the 280 masl level had already been exceeded as of the evening of Oct. 4,” says the committee report, which was released in February 2010.
“The final decision—the donot-spill-yet decision—so that no spillway release was made until midday of Oct. 8, when the reservoir level reached 289.5 masl, thus endangering pertinent dam structures (top elevation of spillway gate is 289.6 m) was, therefore, highly questionable.”
“By this time, maybe they will not commit a mistake anymore,” Uy says. “I’m sure they also learned something [from that experience].”
More than monitoring how the dam water is being managed, Baraan says other concerns downstream of the Agno River must be addressed.
“Personally, I don’t blame the people [at the San Roque Dam] because they were not prepared for it. It was an eventuality that just came and it was so overwhelming that we were really caught unaware,” he says.
What made the flooding worse was that the rivers were not being dredged, he says.
“There is no Agno River flood control effort in spite of the huge amount of money going to the Agno flood control system (an agency under the Department of PublicWorks and Highways),” Baraan says.
“If only the rivers are regularly dredged, it can help retard the flooding of residential and production areas. But because of so many obstructions and siltation, the situation really became very bad,” he says.
Baraan says residents living in high-risk areas, such as riverbanks, should be relocated and prevented from returning to avoid a situation in which many people suffer due to unprecedented levels of floods.
“We have to contend with the fact that these areas are no longer habitable…. We have to exercise political will [to do this],” he says.
He says there should be a special fund to take care of removing all people staying in disaster-prone areas.
Another immediate concern is the replacement of old earth dikes downstream of the Agno River with stronger concrete ones, Uy says.
This is consistent with the investigating committee’s recommendation to redefine the flood control project design and level of protection there, he says, noting that the flood control project in the lower Agno River basin is based on a 10-year flood event.
“Typhoon Pepeng resulted in an 80-year return period flood, thus relegating the bulk of flood control function to San Roque Dam,” the committee says.
At present, the stretch of earth dike from Sto. Tomas town to San Manuel town, which is supposed to be the third phase of the Agno flood control project, has remained untouched because there is no available fund.
Four years after the big flood, Baraan says Pangasinan residents are better prepared to deal with natural disasters.
“We are ready in the sense that people are now aware. Besides, we are better organized now in the municipal and barangay levels,” he says.