Earlier, government scientists warned that a breaching of the crater lake could be "catastrophic."
Senior Superintendent Reynaldo Berroya, Central Luzon police director, said recent rains have increased the level of the Pinatubo crater lake to be only about five meters from the lowest point or notch leading to the Maraunot River. The lake holds over 165 million cubic meters of water.
Berroya said officials of the Zambales provincial disaster coordinating council met yesterday to map out emergency plans as strong rains hit the Pinatubo summit.
Earlier, Raymundo Punong-bayan, director of the Philippine Institute of Volcanology and Seismology (Phivolcs), warned of possible "catastrophic breaching" of the Maraunot notch should the lake rise to its level.
Berroya and lahar expert Kelvin Rodolfo flew over the Pinatubo summit the other day and discovered the crack in the notch and the "alarming" level of the crater lake.
"It’s now too late for any engineering intervention (to prevent the collapse of the Maraunot notch). Our only alternative now is the possible evacuation of affected folk in Botolan," Berroya said.
Berroya said a study is now being rushed to find out which parts of Botolan are facing the most danger. In a "worst case scenario," he said some 16,000 families in this town are at risk.
Phivolcs scientist July Sabit confirmed Berroya’s fears, saying that at the rate of the heavy rains observed in the Pinatubo area in recent days, the crater lake’s level could reach the low notch facing this town within this year.
Last month, he said Phivolcs observed that the lake’s level had a clearance of some six meters from the Maraunot notch.
He said the crater lake holds no less than 165 million cubic meters of water.
Earlier this year, Punong-bayan proposed to the Department of Public Works and Highways (DPWH) several measures to minimize a breakout of the crater lake through the Maraunot notch.
His proposals included the scraping of soft portions of the notch or fortifying it to allow the lake to smoothly overflow to the Maraunot River, instead of destroying the crater wall at the notch.
"I agree with Rodolfo that it’s too late now for any engineering intervention," Sabit told The STAR.
Berroya said he has ordered the setting up of watchpoints along the Maraunot and Balin Baquero rivers so that Botolan folk could be warned before lahar flows reach their communities.
He said that because of the gradual gradient of the slopes toward Botolan, there would be enough time to warn the residents to evacuate.
But he said it is also possible that lahar will flow directly to the South China Sea, skirting heavily populated villages in this town.
Berroya said a measuring gauge will be installed in the crater lake, near the Maraunot notch, to monitor the rise in the lake’s level. "The gauge must be visible enough for monitoring from a flying aircraft," he said.
Meanwhile, Berroya foresees worse floodings in Central Luzon where waterways have remained silted by lahar debris from Pinatubo.
"There are fears that flooding will be worse during high tide," he said, noting studies indicating that the average of one-meter high tide level in the past years has risen to about 1.5 meters.
"At present, disaster management is one of our major concerns," he said.