Kariba Dam rehabilitation on course


Emmerson Njanjamangezi


ENGINEERING works to enhance the structural integrity of the Kariba Dam wall for more efficient power generation is 60 percent done and on schedule for completion by end of 2024, the Zambezi River Authority (ZRA) says.
The dam wall rehabilitation, which started in 2015, seeks to reshape the plunge pool and refurbish the spillway gates, to increase its life span.

ZRA said the project had been minimally affected by the Covid-19 pandemic, which has seen Zimbabwe introduce a nationwide lockdown since March 2020.

“While the project was minimally affected by the first wave of the Covid-19 pandemic, the second wave has also not hindered progress. “The project team has continued to execute its duties with strict adherence to health guidelines issued by the World Health Organisation and health authorities in the two contracting States.

“The project has a clinic on site where regular Covid-19 screening and testing is done. “The spillway refurbishment contractor is working on the establishment of construction site facilities as well as fabrication of electro-mechanical equipment required for execution of the works through specialist sub-contractors.

“The manufacturing progress details are twofold. First, the manufacture of stop logs is being done in China by the subcontractor, Sinohydro Bureau 8. “The works are progressing well and delivery of the first components is expected by mid-February 2021.

“Secondly, the manufacturing of the Needle Cofferdam which is required to isolate the works is being undertaken in Poland by a subcontractor, APC Presmet,” ZRA said in a statement yesterday.

The reshaping of the plunge pool involves excavation of the rock in the pool to increase the pool volume, minimising erosion which can undercut the dam foundations. The existing pool was created by spilling water immediately downstream of the dam wall.

Reshaping the plunge pool includes the construction of a downstream cofferdam to enable the blasting and excavation of an estimated 300 000 square meters of rock from the downstream end and north and south bank sides of the pool in the dry.

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