Utility Maintenance hern Africa if the time, access to water for people in the Kariba and Cahora Bassa catchment areas for drinking, food and agriculture will be severely restricted. Transportation and access to the areas affected will be curtailed. New projects and investment in the region will be severely compromised, as the ongoing lack of electricity and water will make these uneconomical, potentially for up to eight years while the dams are being rebuilt. According to Nico Bianco, Business Unit Head: Corporate and Specialty of Aon South Africa, risk advisors and insurance brokerage, the potential failure of the Kariba Dam is a Southern Africa regional risk that falls into the infrastructure risk category. Should the risk materialise, it would lead to severe power supply constraints – another key challenge currently impacting the region. He states: “The impact will span across the entire risk consequence spectrum, from significant loss of life, damage to property and the environment, to economic fallout. 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.” Rehabilitation and maintenance work required: Plunge pool Spillway torrents have excavated a massive cavern in the Zambezi riverbed, now ten times bigger and deeper than the original design dimensions, that threatens the stability of the wall foundations. It is necessary to reduce the turbulence from water, discharged at 8,000 tonnes a second at times, into the plunge pool below the dam by enlarging the cavern, and allowing the turbulence resulting from the spillway discharge to be dissipated in a less damaging way. Floodgates The dam’s floodgates are designed to release the magnitude of floodwater that occurs once in 10,000 years, so if one gate is out of action for repair and the spillway capacity is reduced it is most unlikely to result in any problem; even with one gate out of action the spillway capacity would probably still be enough to pass the flood event that occurs once in 1,000 years. Floods on the Zambezi take some time to build up so there would be advance warning from rainfall monitoring in the upper catchment, allowing for time to respond. This part of the project will take eight to 10 years to complete, partly because only one gate can be worked on at a time but also because the plunge pool excavation work cannot be done if the lake level is high and the dam is spilling. Completion is projected for 2023. Alkali Silicate Reaction The permanent secretary of the Zambian Ministry of Finance, Felix Nkulukusa, indicated in January 2015 that the danger arose from an alkali-aggregate reaction in the dam wall, which could induce swelling within the concrete mass. In addition, the spillway sluice gates were no longer opening and closing automatically to maintain the required water levels, owing to distortion and swelling of rusting steel components. Darbourn concludes: “Whilst we can debate whether the Kariba Dam will fail, why it might occur and when, there is no doubt that the impact across the region would be devastating. What do you, or your company need to do Safety and reliability to understand and manage your risks around this potential catastrophe? What can you or your company do to support the people responsible for the Kariba Dam rehabilitation project to reduce the likelihood of this event occurring?” ESI Risk - from which perspective? Political & Economic stability Kariba Dam opened 1959 Hydro Electric capacity stabilised Extend life of the dam for a further 100 years Build-up to event - Management of water in Kariba Dam Impact Badly in need of repair lack of maintenance 56 years later Project delay from - Flooding - Governance - Funding 10 years ago Next 3 years are critical Zambezi River Authority (ZRA) Reputation Region - ZRA Electricity generation Hydro power 40% of the 4x 181 billion 3.5 million 8 hours capacity Funders 40% - World Bank - African Development Bank - European Union Tete wiped out after 10 hours , population 1.8 million 1,500 megawatts in South Africa Impact to 30 million Animals Lack of water Food Agriculture Access to region impacted Travel curtailed , border management Disaster relief , funding Economic impact unknown Debt repayment curtailed Kariba Dam water unavailable Challenging project Climate change, $294,2m Flooding, Drought region Electricity Revenue Terrorism Population of the region under review (2011) 116 million 1,8m Malawi - 14,4m Mozambique - 23,0m South Africa - 50,6m Zambia - 13,4m Zimbabwe - 12,8m 2 IRMSA - Aon Risk Research Report | June 2015 The Event and the Impact ... Tsunami like wall of water released downstream - Nation Post Event and the Future ... 2065 - 50 years later 5 - 8 years on-going support Water build up power Funding On-going maintenance Eventual de-commissioning what is their status? IRMSA - Aon Risk Research Report | June 2015 3 Image and infographic supplied by IRMSA and Aon South Africa Manage the dam - Zambia & Zimbabwe