Earth quarry in Davao adds to flashflood woes-A A +A
Tuesday, July 5, 2011
DAVAO CITY -- Quarrying of soil is among the factors that made the flashflood that killed 30 people in the city last week worst, a Mines and Geosciences Bureau (MGB) official said on Tuesday.
Noel B. Angeles, mining engineer of the Mining Environment and Safety Division of Mines and Geosciences Bureau (MGB), said that aside from high precipitation during that day, the loose soil from the quarry across Arroyo Compound in Matina Pangi caused massive siltation.
He said this was made worse by the constriction of river channels, which increased the velocity of the rampaging waters as it broke through the constricted portions.
"Quarrying in a river is not bad since this helps in dredging. What is bad is the quarrying operations of earth fill in Diversion area. Three truckloads of loose soil can easily be swept away by the waters in rain as strong as that one. That's why mud reached the Bangkal area," Angeles said in dialect.
He added that with the abnormally high rainfall that originated from Tamayong, Calinan and Bago Oshiro in Tugbok, upstream gathered so much water, much more than the Matina Pangi River could contain.
"That's why residents were saying that the flashflood seemed to be coming from two directions. It was just the same river but the overflowing water was just looking for some other way to pass through on its way downstream," Angeles said.
Angeles pointed out that the Pangi Bridge upstream bridges a divide of 99 meters, but the Balusong Bridge downstream is only 26 meters wide. This is the river constriction he was referring to. It was like the rampaging river waters were funneled in, increasing its velocity and making it overflow its banks.
Angeles recommends the reclamation of river easements to serve as environment corridors and public access.
"If their places are identified as one of flood-prone, they have to be vigilant and evacuate as soon as possible," Angeles noted.
He recommends the stoppage of quarry operations along the Diversion Road aside from the implementation of erosion control in upstream agricultural lands in Matina Biao, Magtuod, and Talandang areas to reduce siltation further.
Five villages in the city are in a state of calamity after flooding brought by torrential rain hit the city on June 28, killing 30 persons and displacing over 14,000 families. Officials estimate the damage to infrastructure and agriculture at P11 million.
Meanwhile, Davao City Councilor Marissa Salvador-Abella on Tuesday said the quarry site in Matina Pangi is not as hazardous as it looks.
Abella, who chairs the City Council committee on environment, told reporters that a quarrying site in Matina Pangi does not pose danger to residents living nearby.
Abella's son operates a quarrying operation in the area, in a land owned by his brother.
The councilor, however, said she will still seek the agencies that allowed her son's quarry operations, including the MGB, City Mining Board, City Planning and Development Office, City Environment and Natural Resources Office, and the City Engineer's Office.
She said they have all the permits to operate the quarry, adding that if the concerned agencies will say the quarry site is no longer safe, then she will order its immediate closure.
Councilor Jimmy Dureza, chair of the committee on rural and urban development, declined to give his comment on the matter. (Sun.Star Davao/Sunnex)
Published in the Sun.Star Davao newspaper on July 06, 2011.