Kariba Dam wall a ticking time bomb

KARIBA Dam has become a ticking time bomb that could cost lives and plunge the southern African region into darkness should the authorities fail to rehabilitate the dam wall of one of the largest man-made lakes in the world.

Zimbabwe is facing an energy deficit due to limited investment in the capital-intensive sector. As of Monday this week, the country was generating 883 megawatts (MW) out of peak demand of 2 200MW. Kariba hydropower plant generates 500MW daily, but experts say delays in upgrading the dam wall could be catastrophic for the region. The lake is crucial for power generation in Zambia, Zimbabwe and downstream Cahora Bassa hydroelectric generation.

The Institute of Risk Management South Africa (IRMSA) and Aon South Africa issued a report last year written by IRMSA founder member Kay Darbourn revealing that the dam wall would collapse if urgent repair work was not carried out promptly.

"If nothing is done, the dam will collapse in three years," Darbourn warned in her report.

Nico Bianco, the head of the business unit in charge of corporate affairs at Aon South Africa - which is a leading risk advisor and insurance brokerage as well as sponsor of the report - warns of dire consequences should the Kariba Dam collapse.

"The potential failure of the Kariba Dam is a Southern Africa regional risk that falls into the infrastructure risk category, but in addition it would lead to severe power supply constraints - another key challenge currently impacting the region," Bianco said.

"This report shows that all of us in Southern Africa will suffer the impact if this risk materialises and calls for each of us to take an interest and be as involved as possible in preventing this potential catastrophe from happening. The impact will span across the entire risk consequence spectrum, from significant loss of life, damage to property and the environment, to economic fall-out.

"This risk and its potential consequences need to be viewed as part of the existing power supply and demand challenges in the region and will require a strong commitment from governments, private companies and financiers to prevent the failure from happening. By providing this information to our clients and other risk managers in the IRMSA network, we hope to empower you to make the right decisions with regards to the risks you and your company may face."

The World Bank, which has organised the funding for the rehabilitation of the dam, does not share the view proffered by the two organisations that Kariba Dam is on the brink of collapse that could plunge the region into a major power deficit.

However, the rehabilitation of Kariba Dam, which was supposed to begin last year and is expected to cost US$294,2 million, has not yet taken off with expectations that it will now begin next year.

Ministry of Energy permanent secretary Partson Mbiriri told journalists in November 2014 that the rehabilitation of the dam wall, which involves the remodeling of the plunge pool and the refurbishment of the six spill gates, would start in the first half of 2015. He said the remodelling of the pool would cost US$125 million, while the remainder of the US$294,2 million would be used for the refurbishment of the spill gates. The Zimbabwe Energy Regulatory Authority will be the borrower for the project.

Last year Mbiriri told the Zimbabwe Independent in an interview that the expectation of having started the project in the first half of 2015 "was ambitious".

"We were too ambitious with our targets," Mbiriri said. "When you have World Bank and EU as your partners, it is a very thorough process and therefore it will take more time."

A senior official in the ministry who spoke to this paper last month said the project is expected to begin next year.
"The adjudication process for an international contractor to implement and supervise the project is ongoing and we expect the rehabilitation of the Kariba dam to begin next year," the official said. He, however, could not say how long the adjudication process to secure a contractor for the project would take.

Economist John Robertson called the reports "discouraging and alarmist" as work is being done on the dam.

Lack of proper planning and poor management of the Kariba Dam resulted in massive power cuts last year as both Zambia's power utility, Zambia Electricity Supply Company (Zesco) and the Zimbabwe Electricity Supply Authority, through its subsidiary the Zimbabwe Power Company (ZPC), burst their water usage ceiling by huge volumes resulting in an unprecedented decline of water levels in the dam.

The Zimbabwe Electricity Transmission and Distribution Company in September last year introduced a schedule of massive power cuts stretching up to 18 hours a day, attributing this development to low water levels at Kariba Dam, generation constraints at Hwange Power Station and limited imports. The power utility has also blamed weather patterns, especially drought, as well as introducing unusual methods of preserving power supply, which includes the ban on electric geysers.

In a report titled Kariba Dam and Power Crisis: The Cost of Poor Management, Greg Mills, the head of the Johannesburg-based Brenthurst Foundation, which has a global network of top analysts, pointed out that excessive use of water by both Zesco and ZPC is the reason for the current major power crisis in Zimbabwe.

Kariba Dam on the Zambezi River, between Zambia and Zimbabwe, was designed and constructed between 1955 and 1959.

Designed by Coyne et Bellier of France and constructed by Salini Impreglio of Italy in two main phases, the dam was financed by the World Bank and Zambia.