Failing infrastructure a concern

Chairperson of the Randpark Ridge Village Association Roderick Rankine is worried about the state of the infrastructure surrounding the Hymany Dam, waterways and greenbelt in the area.

Rankine, who is a registered professional engineer and construction materials specialist, conducted an in-depth survey of the area in 2017. “More than 18 months ago, I drafted formal peer-reviewed engineering reports on these structures which I gave to our ward councillors and the relevant departments. We are becoming increasingly concerned by the degree to which these structures are continuing to deteriorate and the risks they pose to our community,” he said.

According to Rankine, the dam has started leaking and there is now a large patch of swampy land downstream of the earth embankment where there was previously lawn.

Erosion and deterioration of the concrete side-channel spillway are getting progressively worse, and the concrete floor and rubble masonry guide walls are progressively cracking up and deteriorating.

He noted that individual peak flooding events tend to inflict noticeable damage on the spillway. “Such events are happening more frequently as properties upstream of these structures are covering greater proportions of land with surfaces impermeable to water which discharge their run-off directly into storm water drains.

“If there is a real flash-flood, Hymany Dam could breach in its current state. It could send an avalanche of water and mud down with it that could take out the culvert. It can also easily affect a second culvert near the shops on Randpark Drive. This culvert has several concrete slabs that have become loose over the decades since they were installed. During a flood, this can put the bridge on Randpark Drive at serious risk of collapsing.”

He said that the structure is in a very vulnerable state. If not repaired urgently, the entire dam is at risk of being undermined and destroyed during a single future flood event. “This could necessitate the replacement of the entire structure as well as possible collateral damage resulting in enormous expense. However, by intervening now and implementing the recommended remedial work below, it will be possible to repair this structure, at a relatively small cost, so it will continue to be a fit-for-purpose for the foreseeable future.”

According to Johannesburg Roads Agency subcontractors Evirolution Consulting, a plan has been initiated to initially rehabilitate and upgrade the Seder Street Bridge, with more of the waterway in the future.

Evirolution’s Sameera Ismail said, “As a result of flooding caused by heavy rains, many of the city’s bridges have been severely damaged. This includes this bridge, and the proposed rehabilitation and upgrade of it is the result of an emergency solution. The rehabilitation aims to address problems of mobility for residents that will, in turn, address the issue in safety in terms of crossing the watercourse.”

The assessment report on the rehabilitation is available to view publicly at the Boskruin Library on Kelly Avenue until 9 April.

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