Tuesday, December 9, 2008

December 08, 2008 23:30 PM

Landslides Are Preventable, Says Geo-technical Engineering Authority

By Massita Ahmad

KUALA LUMPUR, Dec 8 (Bernama) -- Most landslides are preventable and Malaysia already has the expertise to drastically reduce the frequency of such incidences, says Dr Ir Nehemiah Lee, a geotechnical engineer and authority on reinforced soil techniques.

Geotechnical engineering is a branch of engineering specialising in assessing the stability and strength of soil and rock materials, as well as groundwater conditions.

Dr Lee, who was previously attached to the Drainage and Irrigation Department, said incidences of landslides were known to geotechnical engineers as slope stability problems.

"The question is whether we are willing to channel resources in terms of expert personnel and adequate funding to resolve the problem," he told Bernama, Monday.

Referring to calls for a total blanket ban on hillside development following the landslide at Bukit Antarabangsa here, Dr Lee, who is now managing director of Nehemiah Reinforced Soil Sdn Bhd, a company employing mostly Bumiputera engineers dealing with reinforced soil technology, said it might not be the most appropriate approach to solve the problem.

Dr Lee, who has been invited to speak on the subject at many international conferences, said the continued growth in population and increasing scarcity of flat usable land would continue to exert tremendous pressure to develop on hilly terrain.

"Even if the total ban is implemented, the problems remain because there are existing slopes that are not stable. Moreover, slopes that are steeper than 35 degrees may be safe whilst slopes that are gentler may not be safe," he said.

Dr Lee said the stability of slopes depended on a host of other factors beside slope gradient.

They include rainfall intensity and duration in the locality, the type of soil, the geological formation, the effectiveness of drainage system and the type of vegetation growing on the slope.

"In addition, there is still a small element of uncertainty concerning the unknown and unquantifiable factors that are beyond the state of the art of geotechnical engineering professionals," he said.

Dr Lee proposed that the way forward would be the establishment of a special purpose body solely dedicated to slope safety management in Malaysia.

This body should be manned by experts in geotechnical engineering and complemented by engineering geologists, soil erosion experts, hydrologists, drainage experts, environmentalists, lawyers, policy makers and regulators.

The role of this body will be to regulate and audit the investigation, design, construction, monitoring and maintenance of man-made slopes, which include cut slopes, fill slopes and retaining walls.

Besides its regulatory role, Dr Lee said the body should undertake research and education, including forensic investigation into landslides, which would help enhance understanding of the causes of landslides.

"Public education is also important to develop awareness of risk and importance of slope maintenance among home owners," he stressed.

Dr Lee said the first task of this body would be to work with private home owners' associations and developers to carry out risk assessment of every existing slope in the country that was a potential threat to public safety.

Any slope found to be unsafe should be strengthened to the required level of safety while any defects and deficiencies in the drainage system should be readily rectified, he said.

As for new hillside development, Dr Lee said this body should rigorously scrutinise the design, construction and maintenance of man-made slopes within the development to ensure compliance with the highest standard of engineering practice.

Above all, he felt that this body should also be vested with statutory powers to approve or reject any new hillside development so that no town council or municipality would issue a certificate of fitness unless prior approval was obtained from it.

Dr Lee hoped incidences of landslide would be greatly reduced with the setting up of the body and that sustainable, environment-friendly development on hilly terrain could continue unimpeded.


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