The Kariba Dam: A Legacy of Power, Displacement, and Adaptation

“The whole might of modern technology was nearly caught by the primeval, savage forces of Africa,” Clements wrote of the Kariba in 1959. (Palini & Scaccabarozzi, 2015).

The Kariba Dam‘s history reflects a clash between colonial powers and local communities over river control. In the 1950s, the Central African Federation, comprising Southern Rhodesia, Northern Rhodesia, and Nyasaland, was formed for economic gain.

Local Africans, especially educated youth who fought in World War II, opposed the federation, fearing Southern Rhodesia’s segregation policies would spread. The decision to build the dam on the Zambezi River was influenced by the federation’s shift in power to Southern Rhodesia.

The debate over dam location, between the Kafue River and Kariba, highlighted the federation’s power struggle. Southern Rhodesia favored Kariba due to its proximity to the new capital, Salisbury, and higher power potential. The dam became a symbol of Western capital’s technological prowess and imperial ambitions.

A Concise Overview

The Kariba Dam, the world’s largest man-made reservoir, is a remarkable feat of engineering. Standing 128 meters tall and stretching 617 meters in length, this double curvature concrete arch dam was constructed on the Zambezi River between 1956 and 1959. Since its commissioning in 1960, it has been a crucial source of energy and economic development for the region, providing hydroelectric power for Southern Rhodesia (now Zimbabwe) and supporting the expansion of Zambia’s copper-mining industry. Situated in the picturesque Kariba Gorge, 398 km downstream from the famous Victoria Falls, the dam has been a major technological marvel and a key tourist attraction.

Beyond Borders: A Stakeholder Saga of Kariba Dam’s Evolution

The Kariba Dam project’s financing and stakeholders reflect a complex mix of national and international interests. Initially a national effort, it received substantial support from the International Bank for Reconstruction and Development (IBRD), now part of the World Bank (WB), providing a crucial US$80 million loan for its first stage. This loan was the largest single loan by the Bank at the time and was part of a larger estimated cost of US$225 million (£80 million).

The project’s origins also had broader geopolitical implications, serving the political objectives of the Federal experiment, a short-lived federation of Southern Rhodesia (Zimbabwe), Northern Rhodesia (Zambia), and Nyasaland (Malawi). The Federal Power Board overseeing the project aimed to enhance the federation’s stability through infrastructure development, prioritizing political and economic goals over environmental and community considerations along the Zambezi River.

Today, the management and future plans for Kariba involve various stakeholders, with the Zambezi River Authority (ZRA) overseeing the dam complex’s rehabilitation. Funding for this effort comes from the Zimbabwean and Zambian governments, with support from the European Union (EU), the World Bank, the African Development Bank, and individual European countries like Sweden.

Beyond Repair: Unveiling the Dam’s Environmental and Human Toll

“Those were rip-roaring days at Kariba, when the place had the atmosphere of a traditional mining camp. The men lived in shacks made of Hessian sprayed with cement. Toward the end of the year, down in the bottom of the gorge where they were working, the temperature rose to 120 degrees. Men carried their tools in buckets of water, because otherwise they got too hot to hold.”

Obstacles and Neglect Before Kariba Construction:

Floods of 1957-58 : Unprecedented floods in 1957-58 posed significant challenges during Kariba Dam’s construction. Reports of exceptional flooding upstream beyond Victoria Falls were received, leading to a rapid rise in water levels at Kariba.The first cofferdam was inundated, and machinery inside the dam had to be hastily removed. The flood caused the road bridge and pedestrian walkway to be swept away, cutting off communication between the two banks of the river.Italian companies remained active in African projects following the completion of Kariba Dam.

Health Hazards: The area was plagued by diseases such as malaria, sleeping sickness, and schistosomiasis even before the dam was built.Despite the known risks, little action was taken to mitigate these health hazards before the construction of the dam began.

Environmental Vulnerability :The Kariba Dam site lay within the Great African Rift Valley, a tectonically active region prone to earth tremors.This vulnerability was not adequately considered or addressed in the planning stages of the dam, highlighting a lack of foresight and environmental awareness.

Lack of Environmental Considerations: Before construction, there were no comprehensive ecological surveys conducted to assess the potential impact of the dam on the environment. The scant scientific investigation into environmental impacts indicated a disregard for the long-term consequences of the project.

Social and Economic Disruption:The construction of the Kariba Dam necessitated the relocation of 56,000 people from the Gwembe Valley. This displacement disrupted traditional subsistence agriculture and land tenure systems, leading to social unrest and economic instability in the affected communities. Insufficient land availability for agriculture and livestock production further exacerbated the challenges faced by the relocated populations.

Aftereffects Caused by Kariba Dam:

Human Displacement: The relocation of the Gwembe Tonga and Korekore people resulted in the loss of their ancestral fields and homeland. The resettlement lands provided were less fertile, leading to serious food shortages and economic hardships for the displaced communities.

Environmental Impact: The construction of the dam led to the destruction of the valley ecosystem and the loss of valuable arable land.The alteration of the landscape and the reduction in arable land availability had long-lasting effects on the environment and the livelihoods of the affected communities.

Social and Economic Disruption Continued:The transformation of the land tenure system and the erosion of women’s traditional rights further destabilized the social fabric of the affected communities. The insufficient land and water resources for increased agricultural production or commercial cropping continued to pose challenges for the relocated populations.

Resistance and Negative Perception:The local Tonga and Korekore populations resisted the dam project, viewing it as a negative interference with their natural ecosystem.They perceived the promised benefits of the dam, such as irrigation and fish farming, to be short- term and outweighed by the long-term destruction of their environment.

Economic Growth vs. Environmental Destruction: While the Kariba Dam project spearheaded economic growth in the region, it came at a significant cost to the environment and the displaced communities. The promised benefits, such as irrigation and fish farming, failed to materialize for the displaced communities, highlighting the disparity between economic gains and environmental degradation.

Kariba South : Power Generation Halted

The Kariba Dam’s reservoir powers two hydropower stations, generating over 10,035 gigawatt-hours annually. Zambia’s ZESCO operates the 1,080-megawatt North Bank Power Station, while Zimbabwe’s ZPC manages the 750-megawatt South Bank Power Station, planning to expand to 1,050 megawatts.

Historically low rainfall caused a significant imbalance in Lake Kariba’s water levels, suspending electricity generation at Kariba South until early 2023. The Zimbabwean Electricity Supply Authority faces challenges due to this imbalance, with most remaining water allocated to Zambia, which has managed its water consumption more prudently.

Managed by the Zambezi River Authority (ZRA), jointly owned by Zimbabwe and Zambia, Kariba Dam exemplifies international cooperation. However, concerns about a potential crisis at Kariba have been growing, reflecting a broader trend of slowing dam construction across Africa due to political and financial issues. African countries are finding it harder to rely on hydropower due to the difficulties in building and maintaining dams, coupled with the increasing impact of climate change on water resources.

Rehabilitating Kariba: Strengthening Africa’s Energy Backbone

The Zambezi River Authority (ZRA), jointly owned by Zambia and Zimbabwe, oversees the Kariba Dam and the Kariba Dam Rehabilitation Project (KDRP). The Environmental and Social Impact Assessment ( ESIA ) and Environmental and Social Management Plan (ESMP) were prepared for the KDRP’s plunge pool and spillway rehabilitation, situated on the Zambia-Zimbabwe border.

The rehabilitation efforts will include reshaping the plunge pool to reduce erosion that could threaten the dam’s foundations. Additionally, refurbishment of the spillway and associated infrastructure is planned to enhance stability and operational efficiency.

Technical Issues Encountered in Kariba Dam :

Plunge Pool Scouring

1. Scour hole formed downstream of the dam due to water falling from the spillway, potentially affecting the dam’s foundation.
2. Rule implemented to limit opening of spillway gates to control scouring.

Spillway Damage

1. Alkali-Aggregate Reaction (AAR) causing swelling of concrete walls, affecting gate functioning.
2. Risk of gates jamming in mid-position, hindering flood control and maintenance.
3. AAR-induced concrete distortion challenging safe spillway operation.

Rehabilitation Components:

KDRP began in 2017 and will be implemented over 7 years. It consists of three components, as follows:

1. Component 1: Institutional Project Support (estimated cost US$69.6 million)
2. Component 2: Plunge Pool Reshaping (estimated cost US$100.0 million)
3. Component 3: Spillway Refurbishment (estimated cost US$124.6 million).

Component 1: Institutional Support

1. Technical services, supervision, and dam break analysis.
2. Panel of Experts for review and advice.

Component 2: Plunge Pool Reshaping

1. The rehabilitation of the plunge pool will include:
2. Access road construction
   
3. Construction of a coffer dam immediately downstream of the plunge pool, which will block off the plunge pool from the downstream river
4. Underwater excavations and concreting
5. Pumping/dewatering of the plunge pool
6. Excavation and reshaping of the plunge pool into terraced steps
7. Fault zone treatment
8. Deposition of excavated rock material in an existing disused quarry on the north bank
9. Annual removal of the coffer dam during high floods, reinstallation and dewatering
10. Final removal of the coffer dam.

Component 3: Spillway Refurbishment

1. Rehabilitation of gates, stop beams, and emergency gate installation.
2. Floating cofferdam for sluice dewatering during refurbishment.
3. Slipway upgrade and new gantry installation for cofferdam assembly.

In conclusion, the Kariba Dam stands as a testament to human ingenuity and international cooperation, providing vital energy resources to Zambia and Zimbabwe. However, challenges such as low rainfall and environmental concerns have highlighted the need for sustainable management of water resources and the careful planning of large-scale infrastructure projects. The temporary shutdown of Kariba South underscores the importance of proper environmental assessments and the long-term impact of climate change on hydropower.

REFERENCES:

Articles

1. Nyandoro, M., 2014. Large dams: Harmony or acrimony with environmental resource management paradigms in Zimbabwe and Lesotho. Special Issue on Water, Bhatter College Journal of Mulfidisciplinary Studies IV, pp.50-67.
2. De Dominicis, F., Pallini, C. and Scaccabarozzi, A., 2015. Rivers, Dams and Large-scale Hydraulic Works in Post-colonial Africa. In African Giants (pp. 148-161). Salini Impregilo.
3. Scudder, T., 2005. The Kariba case study. Pasadena: California Institute of Technology (Working Paper 1227).
4. utf-8”KDRP Revised and Updated ESIA and ESMP – Oct. 2020.pdf

Online sources:

1. 1. CGEP, C.| (2023) The Kariba Dam is failing: What that means for African hydropower – center on global energy policy at Columbia University Sipa: CGEP, Center on Global Energy Policy at Columbia University SIPA | CGEP. Available at: https://www.energypolicy.columbia.edu/publications/kariba-dam-failing-what-means- african-hydropower (Accessed: 26 April 2024).
   2. Joshua Matanzimar. (2024) Zimbabwe: El Niño drought causes major drop in Lake Kariba levels – a disaster for people and Wildlife, The Conversation. Available at: https://theconversation.com/zimbabwe-el-nino-drought-causes-major-drop-in-lake- kariba-levels-a-disaster-for-people-and-wildlife-227245 (Accessed: 24 April 2024).
   3. Serpell, N. (2020) Learning from the Kariba Dam, The New York Times. Available at: https://www.nytimes.com/interactive/2020/07/22/magazine/zambia-kariba-dam.html (Accessed: 27 April 2024).
   4. World Bank Group (2015) The Kariba Dam Rehabilitation Project: Fact Sheet, World Bank. Available at: https://www.worldbank.org/en/region/afr/brief/the-kariba-dam- rehabilitation-project-fact-sheet (Accessed: 28 April 2024).