Jeep tracks in the Geelkrans Nature Reserve were reinforced with Terracrete blocks as a maintenance measure.


As a maintenance measure in order to control erosion in the jeep tracks on the sandy substrates in the Geelkrans Nature Reserve in Stilbaai, Cape Nature was looking for a permanent solution without the impact associated with commonly used hard structures such as asphalt or paving.

Mobicast, a Terraforce licensee in the Garden Route area, suggested the Terracrete paving block, a permeable and interlocking eco-surface paver that can be laid in different patterns and may be used with or without ground anchors for the lining of riverbanks, roads and other areas subject to soil erosion.

According to Jean du Plessis, conservation manager in the area, normal paving is inadequate on the deep dune sand substrate and putting down a road base foundation with compacting would have been very costly.

“Investigating alternative solutions produced the principle of putting down a hard surface that is permeable for water and vegetation. The idea is also that the surfacing material should be able to move with the substrate while keeping its shape and integrity,” he explains. “We decided to use the Terracrete blocks because of their permeable nature, minimal impact on the environment and cost-effectiveness.”

A versatile solution
The blocks are relatively easy to work with compared to other methods that involve more sophisticated machinery and labour. Once the substrate is prepared and levelled, the blocks are packed in the desired pattern, binding wire is threaded through the holes to increase stability and substrate material is used to fill any gaps.

“We get breaking of about 2% of the blocks during handling, as the transport of the blocks requires the material to be loaded and offloaded at least twice due to the nature of the terrain, but on the whole, the process is straightforward and causes very little disturbance in the reserve. Another benefit is that the blocks, if they break, are easy to replace, making maintenance of the tracks quick and simple,” comments Du Plessis.

Construction commenced in March 2013 and is still ongoing. The tracks are installed in stages of 250m, and 7 000 blocks have already been laid down. To rehabilitate any destabilisation that occurred during construction, Carpobrotus edulis (sour fig) were planted on the verges of the track.

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