PETALING JAYA: High soil saturation and pressure from the accumulation of underground water beneath the campsite in Batang Kali had contributed to the deadly landslide, says the Public Works Department.
It said initial investigations indicated that there were two slope failures at the location, which happened within 20 to 30 minutes apart.
“The first slope failure most likely occurred in the camping site.
“The failure has caused the area at the foot of the slope to weaken, resulting in the occurrence of another larger (second) collapse.
“Active underground water flow is detected in the area where the slope collapsed, especially in the campsite area,” the department said.
The estimated dimension of the slope failure is 70m (height), 120m (width) and 330m (length) with an estimated 450,000 cubic meter of rubble soil.
The department said Jalan Negeri B66 in the Batang Kali-Genting Highlands route has been closed since Dec 16.
“The shoulder of Road 66 Section 13.0 from the direction of Gohtong Jaya to Batang Kali has fallen and been damaged by the landslide.
“Tension cracks can also be seen lengthwise on the left lane leading to Batang Kali.
“The roadside drain was also found to have broken and fallen,” it said, adding that a visual inspection of the area found that the drains were clean and dry, indicating that there was no issue with the drainage system.
It said short-term repair works have been implemented to avoid further collapse.
“The works include immediately covering the exposed slope surface with a tarpaulin sheet, redirecting surface drainage water and water from the left drain to the right side, prevent runoff from entering the rubble area, and installation of tilt sensors to monitor ground movement at the site,” it added.
A detailed ground investigation would be carried out as soon as the search and rescue operations are completed.
The Batang Kali landslide has so far claimed 24 lives with nine still missing. A total of 61 people survived the tragedy.