Star Newspaper Article 10th June 2008

Debate on the pros and cons of hillside projects

THE debate on hillside developments has taken centre stage lately following the decision of the Selangor state government to ban projects on Class 3 slopes.

According to developer Datuk David Kong, the ruling is unfair to developers because many have purchased land and have outstanding bank loans to service.

"With the ban, we have less available land to build on. They should let industry professionals give their views and input before deciding on the ruling," Kong said.

Gue: Many issues are unclear and we have to look at the complete picture.

"The previous state government had done a thorough study before deciding that it was acceptable to build on Class 3 slopes (between 25° and 35°). Many developers are now suffering financial losses because of the new ruling," he said.

Kong said that with only limited amount of land to build on, it was hard to offer reasonable prices to purchasers.

"If the aim of the state government is to protect the environment, then it should be clear about it. We agree that it is important to protect the environment but the state must be fair to us. It can gazette the forest and compensate us," he said.

According to geotechnical engineer Prof Dr Gue See Sew, the new guidelines are not clear and some do not add value to safety, environmental protection and sustainability.

"Many issues are unclear and need improvement. The best thing is to get the local authorities to form a taskforce committee comprising professionals from the stakeholders who are familiar with hillside development to look at these issues and formulate clear and comprehensive guidelines and policies," he said.

Gue, an independent consultant specialising in the engineering of soil and rock, feels that there have been many misconceptions regarding such developments.

"We have to look at the complete picture. Yes, there have been many problems but there are also successful projects. Class 4 slopes (more than 35°) had been successfully developed in countries like Hong Kong and Taiwan," he said.

Hutchison: You can't prevent landslides when you have a lot of rainfall, you can only minimise them.

Gue said that in a study he did in 2006, it was found that 88% of landslides out of 49 cases surveyed in Malaysia were caused by errors in design, construction, or a combination of both (see Table).

"The Highland Towers collapsed because the wall and slopes were not properly engineered and the drainage not properly done," he said.

"Even if a slope is less than 25°, landslides could occur if it is badly engineered, like without erosion protection near a stream or river," he said.

According to Gue, some of the major misconceptions are:

1. Soil tests show that a slope is safe
   Fact: Soil tests alone do not tell whether the slope is safe. Soil tests only show the type and properties in soil.
2. Heavy rain causes slope failure
   Fact: Engineered slopes would not fail if properly designed, except when actual rainfall is greater than designed period.
3. Retaining walls always prevent slope failures
   Fact: Un-engineered walls can cause slope failure
4. Environmental impact assessment (EIA) reports ensure safety
   Fact: The EIA is a planning tool. It goes not go into the engineering of slopes in detail.
5. Geological report shows that the slope is safe
   Fact: Geological report does not cover engineering of slopes. It is more on the history of soil and geological features

Gue said that the important slope stability factors included soil properties, slope geometry, groundwater table profile (the level of water in the ground) and slope maintenance.

"The job of the engineer is to analyse these details and to come up with a design that is safe. Engineers must also supervise the work to ensure it is carried out according to the design and specification," he said.

"Even matters like pollution of rivers can be controlled. Stricter fines would make the contractors more careful. There is a need for more stringent controls and regulations," he said.

Gue said that proper and regular maintenance of a slope that had been developed was crucial to ensure it continued to be safe.

"Poorly maintained slopes will eventually fail. The developer or management committee should be responsible for this," Gue said.

"If the area has been handed over to the local councils, for example, where there are roads and adjacent slopes, then they are responsible for maintaining it," he said.

Gue also stressed that abandoning a hillside project would not necessarily make the place safe.

"If you find that a slope is unsafe during construction, stopping the work would not make it safe. Earthwork must continue to improve safety and prevent erosion," he said.

Universiti Malaya geology department professor emeritus Charles Hutchison, however, maintains that engineered slopes are never 100% safe.

"In places like Hong Kong, the earth is mostly granite so it is easier to build on and a lot more stable. Most hills in KL are composed mainly of layers of sandstone and mudstone sitting on overlying limestone," he said.

Hutchison said that even roads on slopes could cause landslides.

"You can't prevent landslides when you have a lot of rainfall. A good drainage system would minimise landslides, not prevent them," he said.

Hutchison said he was puzzled why engineers in Malaysia did not conduct seismic surveys of an area before starting on a project.

"This is done in other countries but it is never done here. Here, they do drilling but with seismic surveys, you can get a good image of the earth formation beneath the surface and that would give you a lot of information about the area," he said.

Hutchison said that there were local companies conducting such surveys for the oil industry.

While he agrees that development is needed, he feels that profits tend to take precedence over transparency.

"I have seen EIA reports that are very thick but are filled with all sorts of technical jargon and equations that do not tell us anything. Many projects were simply approved because people are afraid to say that they don't understand the manual," he said.

"A report might tell you a project is being built on top of a certain soil formation but it does not spell out the consequences of building on these kinds of earth," he said.

Hutchison said he had been asked to be an independent observer but the developers did not allow him to look at anything that involved scientific work.

"It would be good if an outside expert were allowed to see the report. Residents should be allowed to see all documents and bring in their own experts," he said.

According to Hutchison, banning development on hillsides is a good measure because it will minimise the clearing of natural vegetation.

"Plants soak up rain. Flooding is already a widespread problem in the Klang Valley. If you clear away trees and grass, the rain runs downhill and causes floods," he said.

"Putting in more drains only means that water runs into the river more quickly and would still cause flooding at the bottom of the hill," Hutchison said.