01 December 2008



ESTRUCTIVE erosion in the Hammanskraal region of Tshwane has been brought under control following completion of the second phase of a multi-million rand stormwater canal project. It’s happened just in time to divert summer floodwaters away from homes and property in the area.

Hamanskraal Project

Begun in March 2005, the project has involved the laying of tens of thousands of Armorflex concrete erosion-protection blocks along the 2,5km of canal so far built. Phase 3 is due to begin once relocation of residents along the route the canal will take has been completed. The canal will eventually measure about 10km.


Hammanskraal, part of the Tshwane Metropolitan Municipality and with about 1 500 households, has been plagued by flood erosion for many years, and alleviation of the regular suffering of residents in the area from seasonal flooding has come from financing by the Development Bank of Southern Africa.


“Flooding in this area is now becoming a thing of the past,” says Werner Stander, a director of civil engineering company Civil Concepts which has been involved in the canal project from the start. “The protective Armorflex blocks are tailor-made for this purpose. They can be grassed in, which helps slow the pace of the water, further reducing chances of erosion.”


Hamanskraal Project

The grass is growing so luxuriantly in the specially designed crevices in the protective blocks, says Stander, that one can now barely see the concrete lining.



The project has been an impressive example of combined community- and skills-building, says Taco Voogt, commercial product manager of Technicrete, which manufactures the Armorflex blocks. “From the outset, local sub-contractors have been selected for training in block-laying skills, and this formula of tapping into local communities along the lengthening path traversed by the canal has been continued.”


Werner Stander adds: “It’s a very labour-intensive exercise and as the canal building has progressed, many people have been able to receive training in block-laying, a skill which will be very useful for them in the future.”


Over 193 000 Armorflex blocks covering an area of about 17 600m² were used in the construction of the side-slopes and bottom lining of second phase of the canal’s construction, and a similar number in the first phase.