THE OFFICE of the Civil Defense (OCD) XI is assessing five artificial dams in Jose Abad Santos town, Davao Occidental, which were created by the 7.8-magnitude earthquake that struck offshore Sarangani on June 8.
The five sites were identified in the barangays of Butuan, Camalian, Malalan, San Isidro, and Sugal, according to Jose Abad Santos’ summary reports.
The Mines and Geosciences Bureau XI said that possible flashfloods or debris flows might occur should a dam break, which could happen during extreme weather conditions or aftershocks. So, residents living downstream must immediately evacuate for their own safety.
The MGB XI said that artificial dams form when earthquake-triggered landslides block natural waterways.
JAS information officer Julie Marie Buen reported that about 2,000 residents have been evacuated to a safer area as a precautionary measure.
OCD XI regional director Ednar Dayanghirang said they are considering three methods to safely drain the impounded water, which is still undergoing ground evaluations at the municipal level.
The methods include controlled blasting to break open the blockages; manual excavation using manpower; and inserting siphon tubes to allow controlled water drainage.
“The three options will be evaluated by the provincial government of Davao Occidental and the municipal government of Jose Abad Santos, and tonight during our meeting, it will be decided,” Dayanghirang said.
The MGB XI released a GeoHazard Threat Advisory on June 14 following its aerial survey that showed earthquake-induced landslides resulting in five artificial damming in Nuing River in Barangay San Isidro, Sugal River in Barangay Sugal, Butuan River in Barangay Molmol, Malalan River, and an unnamed creek in Barangay Malalan.
The Municipal Disaster Risk Reduction and Management Office of Jose Abad Santos reported another damming in Barangay Camalian.
