GEORGE NEWS - Clearing of vegetation on a section of the mountain slopes above the N2 in Kaaimans Pass has sparked concern over the impact this could have on slope stability. The clearing is part of a road upgrade by the South African National Roads Agency (Sanral).

The cleared section is located opposite the Kaaimans parking area, which is also being upgraded. 

It has been noticed by passers-by, including local environmental activist Mike Leggatt, who said with all the vegetation removed, the likelihood of land or mud slides has increased.

 A landslide could be problematic since the only alternative route, the Seven Passes road between Saasveld and Wilderness, has been closed indefinitely. "The root systems of vegetation is what holds the soil together. Do they plan to cement up that whole wall? I would imagine it must have environmental consequences too.

What studies were done by an environmentalist?"

In the basic assessment report (BAR) for the project, the area around the bridge is described as a "steep embankment with near-pristine vegetation that is very sensitive to disturbance. This section should not be disturbed during the construction period or thereafter".

The report states that vegetation clearing and cut-and-fill activities will take place in certain sections along the N2, which is being upgraded between Kraaibosch and Touw River, and will have a relatively high visual impact.

Some sensitive forest, thicket and fynbos will be lost. Alien plant seeds in the topsoil used for construction can also infest natural vegetation during the works, but these impacts are "fully reversible" when construction materials are removed after construction and the affected areas are revegetated.

Formal complaint

George Herald has heard that a formal complaint has been reported to the Western Cape Department of Environmental Affairs and Development Planning. The department had not confirmed this at the time of going to press.

Stabilisation work to be executed

Sanral project manager David le Cordeur said they are clearing an area of 300m² or more of indigenous vegetation for maintenance purposes, in accordance with a maintenance management plan. "Approval was obtained from the Department of Forestry, Fisheries and the Environment (DFFE) for the removal and trimming of the milkwood trees."

The clearing of vegetation is to allow for the installation of slope stabilisation works to reduce the risk of rockfalls and mudslides.

 "The remedial works include barring down of loose rocks, installation of rock bolts, wire mesh netting and rockfall fences," said Le Cordeur.

In detail the works include:

• Rock barring/scaling and removal of loose rock particles from the slope face.

• Stabilisation of three cave areas by installation of wire mesh netting secured by three-metre and five-metre rock dowels and anchor cables.

• Stabilisation of five wedge instability areas by installation of wire mesh netting secured by seven-metre rock dowels and anchor cables.

• Installation of two rows of catch fencing.

Section leading into Wilderness

Le Cordeur said slope stabilisation works will also be carried out in the section leading into Wilderness.

The detail of these works include:
• Installation of five-metre-long rock dowels or bolts adjacent to existing corroded bolts at maximum two metre offset distance and at the same vertical height as existing.

• Removal of vegetation from lower cut slope.

• Breaking up and removal of large protruding boulders by chemical splitting or other non-explosive methods.

• Rock barring / scaling and removal of loose rock particles from the slope face.

• Installation of rock dowels to in-situ stabilise large boulders or unstable wedge blocks to the cut face (one metre or five metre dowel length).

• Installation of 20-metre-long lined horizontal drainage holes.

• Installation of wired steel mesh rockfall netting system secured by seven metre rock dowels, and top and bottom anchor cables.

• Installation of two rows of shallow landslide fencing (3.5 metre height).

• Installation of 20-metre-long lined horizontal drainage holes.

• No shotcrete will be done on the slope.

Sanral cleared the slope in preparation for installation of slope stabilisation works. 

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