Pics: Sinkholes in Centurion killing area’s economy

Multiple roads were still closed around Centurion months after various sinkholes formed due to heavy downpours of rain.

A business owner in Kruger Street said the business went down the drain when the sinkhole formed across the street, cutting off traffic to a usually busy road.

“We are losing a lot of feet in the door and drive by customers. The street used to be very busy,” said one of the co-owners Azizul Hakim Sayeed.

Customers make a U-turn

Sayeed said the customers had to make a U-turn where the street was closed due to the sinkhole and never saw them again.

“Our customers complain they get to the shop. I tell the customer to drive around the block but they give up and go somewhere else.”

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“We have been robbed twice since the sinkhole. It used to be a busy road but now that it is closed, the criminals take chances,” he added.

Sayeed said they couldn’t pay rent or draw salaries this month.

“Before we were busy, these seats outside were full at lunchtime,” he said.

Councillor Ina Strydom said she was waiting for feedback from the Gauteng Department of Roads and Transport about the sinkhole in Wierda Avenue and Snake Valley Road in her area.

Tender to fix sinkholes out

Lecturer in geographic engineering at the University of Cape Town Lita Nolutshungu said backfilling, grouting and dynamic compaction could be used to repair the sinkhole.

“Sinkholes occur when the ground surface collapses, exposing underlying cavities of varying sizes and at different depths. The formation of these holes is caused by numerous factors. In the South African context, it is mainly attributed to subsidence and dolomitic bedrock which is dissolved by a weak carbonic acid formed when rainwater takes up carbon dioxide in the atmosphere and soil,” she explained.

Nolutshungu said naturally occurring geohazard was exacerbated by ingress of water, poorly managed surface water or drawdown of groundwater.

“The drawdown removes groundwater from cavities within the bedrock or soil layer above the groundwater level (the overburden), resulting in subsurface erosion. It leads to headward erosion ultimately resulting in the surface collapsing, forming sinkholes which can reach diameters of 125 meters and depths of 50 meters,” she said.

Nolutshungu said once the hole was formed, the rehabilitation method was dependent on factors such as the cause of the sinkhole known as the trigger, the geological profile, the size and depth of the sinkhole, intended land use after rehabilitation and surrounding infrastructure.

“Based on these considerations and available resources, one or a combination of these three rehabilitation methods backfilling, grouting and dynamic can be used,” she said.

Sanral said the project to repair the sinkhole was out on tender and would close end of January.

ALSO READ: Video, pics: Sinkholes swallowing Khutsong force residents out of their homes

– marizkac@citizen.co.za