IF you are wondering why towns and cities suddenly found themselves flooded, that’s because the amount of rainfall dumped from August 1 to 16 in Pangasinan was already almost equivalent to two-month average.

This was the finding of chief meteorologist of the Philippine Atmospheric Geophysical and Astronomical Services (PAGASA) in Dagupan, Jose Estrada Jr., when he appeared at the KBP Forum.

He told newsmen that from August 1 to 16, the volume of rainfall was 441 millimeters (mm) and the the normal amount of rainfall in one month is 212 mm.

“We’re already above normal amount of rainfall,” Estrada said.

He added that forecast rainfall this rainy month of August is only 427 mm, to a maximum 630 mm.

He said the equivalent of the rainfall dumped is already almost two months.

Estrada also disclosed that one month’s volume of rainwater was dumped during the three days of continuous downpour during tropical storm Karding, which led to the severe inundation of Dagupan.

He said the amount of rainfall during successive tropical depressions Henry, Inday and Josie that also massively inundated Pangasinan was more than Karding’s rainfall.

Meanwhile, water level at San Roque Dam in San Manuel town is continuously decreasing due to higher outflow than inflow, according to Odette Rivero, spokesperson of the National Power Corporation.

Rivero told the same forum that, “the (main) function of the dam is flood control.”

She said when the rains started to pour, the dam did not start to release water until the dam level reached 287 meter above sea level (masl). “We did not want to reach the peak of the dam so we started our spilling operation”.

Rivero said at 6:00 a.m. of Aug. 16, the water level was at 284.35 masl, with four floodgates open with total gate opening of 4.5 meters.

“Spilling operations continued until it lowered down to 280 (masl) or even lower,” Rivero added.

Rivero said water released from San Roque Dam goes directly to the Agno River but its immediate effect is at the area where the water is dumped. “But as it goes away from the Agno River, there are many other river tributaries that contribute to the water so if that is the concern (flooding), the water does not come from San Roque Dam alone as the source (of flooding),“ Rivero clarified when asked about the contribution of dam water released to the flooding.

She said mobile patrols of San Roque go around to monitor water flow in different flood stations.

Meanwhile, Rivero said since Aug. 15, spilling operation of Binga and Ambuklao Dams have been turned back again to SN Aboitiz because of decreasing inflow and outflow data.

“This means levels are more manageable,’” she said.

At around 8:00 a.m. of August 16, Rivero said the five gates opening have been reduced to four gates at 2 meters only in Ambuklao Dam.

In Binga Dam, the six gates opening were down to four only at 2.5 meters, she added.

“We are focused on these because they contribute water that goes to San Roque Dam,” she said. (PhilStar wire service)

 

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