PETALING JAYA: Poorly maintained drains along a state road could be the likely culprit behind the recent Batang Kali landslide disaster, says an expert, based on initial observation.
Universiti Sains Malaysia’s (USM) Mastura Azmi said looking at the photos and videos of the landslide, the tell-tale signs were clear on the road directly above the affected slope, Jalan Batang Kali-Genting Highlands or route B66.
“The first signs are cracks on the road’s surface. That shows water had infiltrated the surface. This can be attributed to poor drainage.
“When there’s a crack or gaps in drainage, water seeps underneath the pavement.
“In this case, the excess water would have flowed through the bare soil to the other side of the road, that is toward the slope over where the campsite is located,” the geotechnical engineering lecturer told FMT.
Mastura, who specialises in slope engineering and the study of landslides, said typically, hillside roads like the one in Batang Kali tend to have a reduction in slope stability due to tension cracks and are made worse with surface runoff and water coursing its way. This would lead to soil movements.
“The movement of water may come from higher slopes onto the road or cause water to course beneath the drain as it was either poorly maintained or unable to take the intensity of the water flow,” she said.
Mastura stressed that maintenance of drains, especially at hillside roads was very important. She called for an urgent review of drainage capacity and maintenance on all hillside roads to avoid a repeat of the landslide.
The landslide involved an area of 500m in length, 200m wide and a depth of 8m, moving approximately 450,000 sq m of soil across the campsite. So far, 24 people have died in the tragedy, with nine others still missing.