20 September 2012


Construction of a new storm-water control system lined with Technicrete Armorflex erosion-control concrete blocks is under way to protect the environment of a nature reserve adjacent to a major Pretoria vehicle manufacturing plant where zebra, blesbok, impala and other wild life roam.

Seasonal storm-water flooding had caused extensive soil erosion between two existing dams, and serious damage to the overflow channel from one of the dams near the Ford plant at Silverton outside the capital. While there had been no damage to the old overflow channel, a new one had to be built which could control a greater overflow of water.


All land owners are required to control their storm-water before it is dispersed into the main storm-water network, and the area local authority had requested that storm-water run-off from the plant be channelled through a single control point.


ArmorflexTwo main Armorflex-lined channels will finally perform this task – a northern channel and a southern channel to carry all the surface run-off from the Ford plant. A third linking channel between the two dams and an overflow channel are also being constructed. Storm-water from the plant runs into the first dam and overflows into the second. In addition to the eroded feeder channels, one of the dam walls had to be repaired and upgraded – another job for Armorflex.

Almost 6 000m² of the concrete blocks are being used in the operation, supplied by the Olifantsfontein plant of Technicrete, a member of the Murray & Roberts Building Products group.


Two-stage upgrade


The upgrade is being constructed in two stages, the first of which has been completed and ends at the boundary of the Ford property. The second stage - now under way - extends the outflow onto municipality land. When completed, approximately 1km of channeling will have been lined with Armorflex, in addition to about 300m of dam wall.


ArmorflexThe second phase involves various weirs as well as Armorflex on the side slopes of the channels,” says project manager Martin van Veelen of AJCOR Civil Projects, a specialist in infrastructural engineering such as road construction and rehabilitation, setting ponds and pollution-control dams. Main contractor is J.C. van der Linde & Venter Projects.


“This has been my first experience with Armorflex, which was specified by the professional team,” van Veelen said. “In addition to its interlocking capability, it has added aesthetic quality because it allows grass to grow in between the concrete blocks and eventually cover them, giving the channels a very natural look.”


He added that it would only be known next rainy season just how well the new system performed, but added: “It is a massive upgrade of what was there previously.”