Assignment 1– The Kariba Dam

Things built against nature will always have consequences. As the world’s largest artificial dam, the Kariba Dam in Zambia faces great danger. The erosion of the rock has been wearing away the dam’s foundation. The climate changes which would lead to large floods also impose great threat to the stability of the dam. According to the “Business Day” published in the South African paper, engineers have come to an agreement that there’re only several years left for the Kariba Dam to be repaired. If action is not taken, the result would be terrifying and unpredictable.

Here’re some basic information about the Kariba Dam. With a 180\(\text{km}^3\) storage capacity, the dam’s main purpose is to provide hydropower to the surrounding countries. The Kariba Dam has four generators and each is supplying 150 megawatts.

\[150\text{MW}\times4=600\text{MW}\]

However, according to a report of the failure of the Kariba Dam released by the institute of Risk Management of South Africa, the erosion of the plunge pool has increased 8 times:

\[(295\text{ft}\times\frac{0.30\text{m}}{1\text{ft}}-10\text{m})\div10\text{m}\approx8\]

The current concern is that if the eroding is getting towards the dam wall, the 128m-high wall would be under great danger of failure. The chemical reactions would slowly swelling the concrete wall and thus the spillway gates might be unable to operate well in the future.

The potential failure of the Kariba Dam is not only putting millions of lives at risk, but also cutting of one of the major power sources–electricity, which would lead to a series of other problems. The Zimbabwean and the Zambian governments have been raising money to repair the gigantic dam.

According to the BusinessDay, several agencies including the European Development Bank, the World Bank, the Swedish Government and the African Development have been funding on the repairing work for the Kariba Dam.

\[\$100\text{million}+\$75\text{million}+\$47\text{million}+\$75\text{million}=\$297\text{million}\]

The repairing work is a a large process and it includes reshaping the plunge pool to minimize the erosion of the Dam wall and improve the six flood gates. This process might takes up to 10 years. Here’s the costs of 1 day for the repairing work.

\[\$297\text{million}\times\frac{\$1,000,000}{\$1\text{million}}\times\frac{1}{10\text{years}}\times\frac{1\text{year}}{365\text{days}}=\$81370\]

However, questions do arise–is it better to build a new dam? Since the repair time and cost are all estimated, the less time it takes, the less money it would spend. Thus it would be best to also consider the money spend on building a new dam by comparing the daily costs. Historically, the Kariba Dam is built from 1955 to 1959 at a total cost of $480,000,000. Thus the daily costs could be calculated as following:

\[\$480,000,000\times\frac{1}{10\text{years}}\times\frac{1\text{year}}{365\text{days}}=\$131506\]

In conclusion, assuming the maximum repairing time is 10 years, the daily cost of repairing is less than the daily cost of building a new dam. On the other hand, building a new dam would still pose the same problems as in today. Thus the wisest decision would be to repair the dam as soon as possible.

  1. History of the Building of Lake Kariba — An article posed at Zambiatourism.com pinpointed the historical background of building the world’s largest artificial dam. It also addresses the issue about displacing the tribes who originally lived there. This article has a fairly good credibility because it’s published by the Zambiatourism and it’s supported by the local government. This website also provides an exceeding amount of information about Zambia.
  2. Impact of the Failure of the Kariba Dam — An article published by The Institute of Risk Management South Africa is a risk report focused on the impact of the failure of the Kariba Dam. This article has a very strong credibility because the Institute of Risk Management South Africa is a very professional association for risk management in South Africa.
  3. To the rescue of Kariba Dam — This article published by BusinessDay is an article that aims to find the solutions to prevent the “catastrophic failure” of the Kariba Dam. The Business Day is also a trustworthy news organization but the information might be more from the business perspectives as investors so the credibility is fairly well but it’s definitely not as useful as the scientific studies.
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