Lake Kariba Rehabilitation Nears Completion - ZRA
The Zambezi River Authority (ZRA) has said the rehabilitation of the Kariba Dam is now close to completion.
The Kariba Dam Rehabilitation Project is funded by the African Development Bank, and the European Union with counterpart funding by Zambia and Zimbabwe.
The rehabilitation of the reservoir has two work components – the plunge pool reshaping and the spillway refurbishment.
Lusaka Times reported ZRA chief executive officer Munyaradzi Munodawafa as saying reshaping works are at 74 percent completion with a disbursement ratio of 75 percent.
He said the coffer dam has been completed, about a 36-metre depth of the plunge pool has been dewatered and the preparatory works for the fault zone strengthening measures have started. Said Munodawafa:
To date, the project has realised several significant milestones which have gradually drawn it much closer to completion, despite the numerous challenges and setbacks that have been encountered since commencement.
Significant progress has accrued in implementation of the spillway rehabilitation work, with key milestones achieved todate being the successful installation of the coffer dams in sluices six, three, two and one.
The expected date of completion of the spillway refurbishment works is February 2025,
Lake Kariba has been in operation since 1960 and has been meeting the water needs of the two power utility companies – ZESCO in Zambia and ZESA in Zimbabwe – for power generation.
However, the safety of the dam faced the threat of being compromised by two major deficiencies relating to the plunge pool and the spillway, according to Munodawafa.
He said the plunge pool has progressively deepened on account of the forces of the spilling water jets.
Munodawafa said the abrasion within the plunge pool, to its current depth of about 80 metres has been accompanied by preferential erosion towards the dam foundation. This can result in catastrophic dam failure.
Moreover, the spillway facility has been affected by an alkali-aggregate reaction, a concrete swelling phenomenon that causes operational challenges for the hydromechanical parts of the facility.
One of the consultants engaged by ZRA, Mott MacDonald, said that a catastrophic failure of the dam would result in the loss of over three million lives in the downstream riparian communities.
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