The Kariba Dam is a double-curvature concrete dam in the Kariba Gorge in Zambia. Situated on the Zambezi River, the dam stands 128 meters tall and 579 meters long. Lake Kariba extends for 280 kilometers because of this dam and holds 185 cubic kilometers of water. The Government of the Federation of Rhodesia and Nyasaland passed the orders for the dam. The arch dam was constructed between 1955 and 1959 by an Italian firm Impresit.
A Brief History
The history of the Kariba Dam dates back to the 19th century. The Kariba Gorge was studied for the construction of a bridge. Between 1946 and 1955 a series of events led to the construction of the Dam. After World War 2, the drive for industrial development led to an agreement between Southern and Northern Rhodesia. The two colonies of Britain needed cheap electric power for various activities. The main purpose of the dam was production of hydroelectricity.
The Construction
Strategic considerations related to energy, security and economic development of two countries Zambia and Zimbabwe led to the construction of Kariba Dam. Both countries were experiencing population growth and urbanization, which increased the electricity demand. The dam could provide a reliable and renewable source of energy by harnessing the hydroelectric potential of the Zambezi River.
Sir William Halcrow was a pioneering figure in the field of civil engineering. With a background in hydraulic engineering and dam construction, he brought a wealth of expertise to the project. As the chief architect, he collaborated with other engineers and construction firms to achieve the design and execution.
The construction of the Kariba Dam required extensive planning coordination and resources. Numerous support staff and skilled laborers worked with the engineers to bring the revolutionary design to life. Construction camps were established along the Zambezi River providing accommodation, amenities and logistical support to the workers and their families. Its completion in 1959 was a milestone in African architecture and signaled the beginning of a new era of development.
Construction Timeline
In August 1955, the Federation of Rhodesia and Nyasaland initiated the search for contractors. By July 1956, Impersit(now Salini Impregilo) , an Italian firm, got the contract and excavation began in September. Operation Noah was executed between 1958 to 1964. There were two floods between 1957 and 1958 which destroyed equipment and roads. The Kariba Hydro Electric Scheme was inaugurated in 1960.
Power Generation
The Kariba Dam supplies electricity to both Zambia and Zimbabwe. Both countries have their own power stations on respective backs of the river. Zimbabwe’s station towards the south has been in operation while Zambia’s station since 1976. In 2016 it was reported that the water levels at the dam have dropped to 12% of its capacity. Low rainfalls and overuse by power plants has left the reservoir empty.
Environmental Effects
The Kariba Dam affected the surrounding ecology in several ways. The vegetation in the river basin was cleared for gillnet fishery. Due to the decomposing vegetation the soil which became the bottom of the lake became extremely fertile. Additionally, numerous fish species like the kapenta have been introduced in the lake leading to the growth of the fishing industry. Fish eagles, cormorants and other water birds visit the shorelines along with a large number of elephants, lions, cheetahs, leopards and buffalo.
The Tonga settlements around the Zambezi Valley had to be relocated because of the construction. Their occupation was riverine and upland farming, livestock rearing, hunting, fishing and manufacturing. About 57000 people needed to be relocated but the available land was not enough. The resettlement took place in 1957 and 1958, reports suggest that people were moved by force majeure. The new land was not suitable for riverine farming. The reservoir is located in a tectonically active area and has caused numerous earthquakes. While most of them were minor, a few measured as high as 5 on the Richter Scale.
Tourism
Since the Kariba Dam, a thriving tourism industry has developed around the lake. To its west is the Matusadona National Park, where rescued wildlife found refuge after Operation Noah. Lake Kariba also has several islands, such as Maaze, Mashape, and Chete Islands on the Zambian side and Sampa Karuma, Fothergill, and Spurwig Islands on the Zimbabwean side.
Costs and Benefits
The main stakeholders were the governing bodies of the two countries and indirectly their citizens. The World Bank was a financial stakeholder as they had sanctioned a loan for the project. The Tonga people were never considered as stakeholders and were wrongly relocated from their home lands. This proved to be a traumatic event for all of them except a few who used the compensation money well. Those who relied on the production of electricity, the copper mines and other industries benefited from this project the most. Other beneficiaries included employees of the national parks, fishermen and workers in the fish industry. The people living in areas where coal plants would have been built were the indirect beneficiaries. They got cleaner air and less acid rain as a consequence of the reservoir.
The Kariba Dam has faced challenges due to declining water levels, structural concerns and threats of failure. Rehabilitation is underway and completion is expected in 2025. Despite the positive and negative aspects of the Kariba Dam, it remains one of the largest dams ever constructed. The project stands as a milestone in infrastructure development.
References:
- (No date a) Kariba Dam Facts for Kids. Available at: https://kids.kiddle.co/Kariba_Dam (Accessed: 14 May 2024).
- (No date b) Kariba Dam history, Location & Impact | What is the … Available at: https://study.com/academy/lesson/kariba-dam-history-location-impact.html (Accessed: 13 May 2024).
- Kariba Dam (no date) Facts and Information. Available at: https://www.victoriafalls-guide.net/kariba-dam.html (Accessed: 14 May 2024).
- Mutazu, G. (2014) Kariba Dam Zambia and Zimbabwe, Academia.edu. Available at: https://www.academia.edu/6971886/Kariba_Dam_Zambia_and_Zimbabwe (Accessed: 14 May 2024).
- World’s Largest Manmade Dam Has Less Than 1% of Usable Water (no date) Bloomberg.com. Available at: https://www.bloomberg.com/news/articles/2023-01-03/world-s-largest-man-made-dam-has-less-than-1-of-usable-water (Accessed: 14 May 2024).
- Kariba Dam (2023) Wikipedia. Available at: https://en.wikipedia.org/wiki/Kariba_Dam#Recent_activity (Accessed: 14 May 2024).
- The construction of Kariba Dam 1957 (2016) YouTube. Available at: https://www.youtube.com/watch?v=WxekPPFjBzI (Accessed: 14 May 2024).
