Changing a road to save plants

Realigning a road and ramp is how far SANRAL will go to save indigenous and endangered plants. As a result, the road turned out more expensive but it saved some of the country’s precious plant heritage.

These far-reaching steps were taken by the national roads agency when it upgraded the N7 in the Western Cape between Melkbosstrand Road and Atlantis. Conserving the Swartland Shale Renosterveld was a significant environmental challenge as both were affected by the widening of the road and the construction of new interchanges.

An environmental assessment had found that the vegetation was deemed to be vulnerable to critically endangered and that mitigation measures would not reduce the loss of these highly valued conservation species.

The only way was to realign the road, despite the cost implications. At Melkbosstrand the alternative alignment crossed over the existing road before looping back to reduce the direct impact on the vegetation in question, thereby saving some 25,000 square metres of these endangered species.

But not all could be saved, so the rest were relocated to a site identified in consultation with the City of Cape Town.

The loop of a ramp at the Atlantis Interchange was reconfigured to a larger radius, thus maximising the area to be conserved within the interchange. The roads agency has taken responsibility for their long-term conservation too.

Particular attention was paid to the drainage mechanisms to ensure that the hydrological regime of the area will not be significantly altered by the road.