Sanral: Drains were overburdened
JOBURG - Sanral is assessing the damages to its toll route after flash floods swept over the road on 9 November.
The South African National Road Agency Limited (Sanral) announced on 10 November that a team of engineers will inspect its road network the N3 highway, following flash floods on 9 November.
Sanral engineers conducting the first infrastructure survey will look for obvious signs of damage to roads and bridges to make sure they are safe for use. The agency said it is monitoring the possibility of soil erosion or sinkholes opening up.
The rainfall was so extreme that it is likely to be a once in one hundred years occurrence, Sanral said. According to Edwin Kruger, Sanral’s bridge network manager, in any year there is a five per cent chance that a flood of this magnitude or greater will occur on Sanral freeways with a design recurrence period of 20 years.
When it did hit on 9 November, run-off from failed drainage systems increased and built up in low-lying areas, like Gillooly’s Interchange.
“With the large volume of rain that fell in a very short space of time, much more water found its way onto the road due to the storm water systems being overburdened,” Sanral explained in a press release.
Alex van Niekerk, Sanral project manager, said there is an accumulative effect when the storm water drainage in the surrounding area cannot handle the water run-off.
“It continuous to swell causing a flash flood,” he said.
The blocking of storm water pipes, culverts and bridges by homeless people is also increasingly becoming a problem, Sanral said.
