KUALA LUMPUR - THE landslide in Lebuhraya Mahameru on Tuesday was caused by the loosening of soil at the bottom of a slope.
Mayor Datuk Ahmad Phesal Talib said the slope was undergoing soil stabilisation work, which began on Oct 7 and was scheduled for completion in March.
"City Hall has been taking action based on the recommendation of Ikram, or the Malaysian Public Works Institute, following a landslide at the same spot in May.
"The soil at the bottom of the slope started to loosen when the repair works were in progress and the downpour triggered another landslide."
Phesal said the stabilisation work would continue as soon as possible and would be completed on schedule.
He added that City Hall had installed temporary concrete barriers in the area as a precautionary measure. As a long-term solution, he said, a hazard map, which would list hazardous and risky slopes in the city, was being prepared by Ikram.
"City Hall will use this map to identify slopes that need attention, and rectify slopes that are deemed to be weak."
Tuesday's landslide, which occurred in front of Wisma Tani, led to a massive traffic snarl in Lebuhraya Mahameru between 5.20pm to 10pm on the Jalan Tun Razak-bound lane.
By yesterday morning, two of the three lanes in the highway were reopened, with one lane between Bukit Tunku to Lebuhraya Mahameru remained closed to enable City Hall workers to clean soil and debris.
Department of Irrigation and Drainage water resources and hydrology director Datuk Hanapi Mohamad Noor said rain that fell on bare soil or cut land would create a burden on soil structure, thus, triggering an erosion.
"After the first incident in May, the authorities had used canvas to cover the slope. This canvas reduced the burden of the slope when there is a downpour."
He said he suspected the canvas was removed when the soil stabilisation work was done and when it rained, there was no protection for the bare soil.
"If possible, construction should not be carried out in the rainy season. If there is no choice, precautionary measures should be taken at all times."
Hanapi said any construction or earth works should have been done in stages, and that contractors should have ensured that land not undergoing works was covered with canvas at all times.
"The entire slope should be covered when the contractors are done with their work for the day," he said, adding the hydrology aspect of slope management should also be taken into account when dealing with risky slopes.
Slope Watch programme director Emiko Motoyama said local authorities should engage with the public and start up a slope monitoring and response initiative.
Centre for Environment, Technology and Development chairman Gurmit Singh said nature should not be blamed for recurrence of landslides as the Meteorological Department would have an indication if the weather was going to be bad.
"The authorities should be on their toes and take action as soon as there is the slightest indication of a landslide and should continuously monitor risky slopes and not allow development in steep slopes."
Kuala Lumpur Fire and Rescue operations chief Samsol Maarif Saibani said traffic flow was smooth, and traffic policemen were assigned to control traffic flow at the location.