Areas in Hulu Klang sit on 'weak' rock

New  Straits Times 12/6/2006

KUALA LUMPUR: Eighty per cent of Hulu Klang is at risk of landslides. Other high-risk areas are Hulu Langat, Puchong and Hulu Selangor, especially along the Pahang-Selangor border.

A soil expert said a study done two years ago showed that some areas in Hulu Klang sat on "schist rock", the weakest rock on which to carry out any sort of development.

"For instance, Kampung Pasir, where a landslide occurred recently, sits on schist rock. It was only a matter of time before the land gave way," he said.

He added that the Ampang Jaya Municipal Council and the State Government were informed of the Kampung Pasir situation two years ago.

The council had also been informed of other hill-slope developments that needed monitoring, he said.

"One of the spots needing attention is a high-rise condominium on the peak of a hill. The Government should immediately install an early-warning system to avoid another Highland Towers tragedy," the expert warned.

Much of Puchong, he noted, was ex-mining land and the Government should monitor underground water there.

"During the rainy season, the land rises slightly as underground water pushes up the surface, and during the hot season it caves in slightly. This constant movement creates soil tension."

He said the initial indicators of soil movement were cracks on walls.

The Hulu Klang and Hulu Selangor areas, he said, sat on decomposed granite and therefore any development should be monitored closely.

He said about 10 per cent of Kuala Lumpur was built on limestone rock.

"City Hall is aware of the areas and should take immediate measures to install early-warning systems or other mechanisms to detect soil movements," he said.

Geologist Prof Dr Ibrahim Komo said a zoning system should be used to differentiate danger zones from safe ones.

"This could apply to existing housing and commercial areas and for future development."

He said some high-risk areas may be developed.

"There is always a risk when development is carried out in ex-mining areas. But that does not mean we cannot build in such places," he said.

Ibrahim said proper engineering mechanisms could be used to stabilise such areas.