PETALING JAYA: Any construction on hills and slopes should have an erosion and sediment control plan, says certified erosion and sediment control expert Datuk Ahmad Fuad Embi.

       The engineer and founding member of the Malaysian Stormwater Organisation emphasised the importance of ensuring drainage systems in hilly areas were properly maintained to prevent water from seeping into the ground, which could lead to landslides.

       Referring to the Highland Tower incident as an example, Fuad said one of the reasons behind the major fatal incident was the roadside drain with cracks that allowed water to seep into the ground.

       “The roadside drain was made of concrete and it had many parts that were cracked, possibly due to ground movement or maybe it was built using low-quality materials.

       “Tonnes of water seeped into the slope via these cracks, causing the soil in the area to become heavier. It also reduced friction and all these factors then caused the slope to collapse.

       “That is why it is very important to maintain all hillside drains, with residents helping to monitor the situation.

       “Water cannot be allowed to flow over a slope, it will cause erosion and seep into the soil,” explained Ahmad Fuad, who is also a former Irrigation and Drainage Department deputy director-general.

       Geologist Ng Chak Ngoon said that while landslides could not be completely eliminated, some measures could be taken to at least prevent such incidents, especially in heavily populated areas.

       “Strengthening all such slopes is costly. With limited resources, the most viable strategy will be to identify the slopes that are most likely to fail, followed with a programme to monitor and, where viable, reinforce.

       “While it is not possible to predict exactly when a slope will fail, it is possible to identify unstable slopes which may eventually fail.

       “For instance, on the Taman Bukit Permai slope, the trees which should normally be upright were leaning towards the downslope direction indicating potential failure.

       “Therefore, identifying such signs on unstable slopes can serve at least as an early warning for evacuation or close monitoring and thus save lives,” he added.

       Ng, who visited the Taman Bukit Permai landslide area on Sunday, believes that water leaking from a drain near the area could be a reason behind one of the two landslides in the area.

       “The occurrence of two landslides along the same slope suggest that instability is not confined to an isolated location along the slope but probably more widespread.

       “If the rainy period continues as it is, more landslides may occur along the slope.

       “Leaning trees along the slope suggests the possibility of future landslides along the same slope,” he cautioned.

       He also believed that the government should be transparent and release reports on every landslide incident.