City engineers scramble to fix 'ticking time bomb' dam wall in Benoni

Repairs to the partial wall collapse of Middle Lake in Benoni, east of Johannesburg, are under way.

Phase one is expected to be completed by Monday next week at an estimated cost of R1.8m-R2m, excluding VAT.

Ekurhuleni metro spokesperson Themba Gadede said the first phase of repairs had to do mostly with addressing the risk of potential failure of the dam.

The huge dam, which borders the N12 highway, collapsed on December 23 last year, causing panic among residents.

The metro was quick to put in place tons of sandbags to avert further cracking. But longtime Benoni resident Johan Bezuidenhout said this would not solve the problem.

"The residents are panicking as they don’t know what could happen. Ekurhuleni should maintain the infrastructure and must never wait until there’s a disaster. Come next year we don’t want to read in the media about a contract awarded to a wrong company to fix this dam – all should be above board," he said.

The dam is one of four  along the N12 route that are used as recreational facilities by local residents.

Gadebe said they expected to complete all repairs in six months, provided there were no major floods or further failures.

The next phase will include the design and construction of emergency repairs to the rest of the spillway. "Among other things, the next phase will include resealing of joints in slabs and filling of cavities under the remaining slabs,” said Gadebe.

He said the emergency repairs were much cheaper than the cost of replacing the dam, which he said was estimated at between R60m and R100m. "The repair cost is therefore a very small percentage of the replacement value."

The municipality has been working with the department of water and sanitation. A structural engineer from from the department said the metro could not work alone on the problem.

"This lake has millions of tons of water. Had it totally collapsed, many along its way, including other infrastructure like bridges, would have been swept away and cost billions of rands to clean and repair - and would take months to be properly done," said the engineer.

He said the department had to act quickly. "This is a ticking time bomb and all should work together."

In a joint statement with the metro, water and sanitation spokesperson Sputnik Ratau said danger was being averted and lives saved. "A joint operations committee was immediately established on December 23, which helped to prevent loss of lives and damage to properties downstream," said Ratau.

"The committee is made up of experts from key departments in Ekurhuleni, the Gauteng department of agriculture and rural development, the provincial and national departments of water and sanitation, and Rand Water."