Shotcreting often needless, critics charge

PUBLISHED : Monday, 03 January, 2011, 12:00am
UPDATED : Monday, 03 January, 2011, 12:00am

It destroys vegetation, creates eyesores and is supposedly discouraged by the government - yet hillsides and slopes around the city continue to be covered in unsightly grey cement, sprayed on to prevent landslides in a process known as shotcreting.

In some cases, such as a 200-metre strip of hillside along Magazine Gap, the land is privately owned and not subject to the strictures the government places on itself. The upper part of the slope, topped by 27 Magazine Gap Road, a private residence with sprawling views of Central on one side and Ap Lei Chau on the other, has been sprayed with concrete after the soil beneath was compacted and covered with wire mesh.

But the lower part, owned by the government, has been stabilised with a retaining wall.

When the government wants to stabilise a slope, it uses hard covers such as shotcrete only as a last resort or in an emergency - after a landslide for example - and it has to get approval from the Vetting Committee on Slope Appearance.

Other slopes are stabilised with methods such as netting and vegetation, which looks better and lowers temperatures by absorbing carbon dioxide instead of reflecting heat.

The Buildings Department gave guidelines to private developers in 2002 discouraging the use of shotcrete, but there is no legislation to enforce them. Melanie Moore, a 13-year resident of The Peak and member of the Lung Fu Shan Environmental Concern Group, said the Magazine Gap Road work showed a double standard.

She called it another example of Hong Kong's natural slopes being unnecessarily destroyed by shotcrete.

'No vegetation will grow on them, they're not natural and they don't blend into the environment,' Moore said. 'It is a consistent problem in Hong Kong.' Leonard Tang, director of Halcrow China, consulting engineers for both sections of the work, said it was common practice for slopes with an angle of less than 55 degrees to be reinforced with shotcrete.

'We don't want to shotcrete, but public safety is still one of the concerns,' he said.

Jim Chi-yung, chair professor of geography at the University of Hong Kong, said the practice was often used as a quick fix for slope reinforcement in non-essential situations. Jim said the government ought to apply its own policy - of vetting applications to use shotcrete on slopes - to private developers.

'Shotcrete should not be used unless there are strong justifications showing that there are no alternatives,' he said.

'We tend to put too much emphasis on the engineering requirements and forget about the landscape, environmental and ecological requirements,' the professor added.