The Kariba Dam was constructed between 1956 and 1960 creating at that time, the largest man made Lake in the world - Lake Kariba . The Dam was officially opened by Her Majesty Queen Elizabeth the Queen Mother on May 16 th 1960 with the switching on of the first electricity generators, bringing to life one of Africa's most ambitious projects. At the time of its construction, the Kariba Dam was known as “one of the engineering wonders of the world”, a double curvature concrete arch dam wall standing at a height of 128 metres above the river bed and spanning 617 metres across the Kariba gorge blocking the path of Africa's second largest river – the mighty Zambezi. The building of the Dam wall created an “inland sea” stretching 280 kilometres in length, covering an area of over 5,500 square kilometres and holding back more than 180 billion tonnes of water. The Dam Wall is host to two of Southern Africa's most important electricity generating stations, Kariba North Bank Power Station on the Zambian side and Kariba South Bank Power Station on the Zimbabwe side, between them generating a total of 1,320 Mega Watts of electricity. The construction of the Kariba Dam and subsequent formation of the Lake had a significant impact on the development of Zambia as we know it today. Costing over US$1.2 billion (in 1998 money) and the lives of nearly 100 construction workers, the Kariba project has undoubtedly contributed to the economic and social development of Zambia and changed the lives of the people of Zambia – none more so than the Batonga people, the “displaced tribe” of the Zambezi valley whom, in some cases, were forcibly removed from their ancestral homes to make way for the rising flood waters. Lake Kariba today is not only the home of one of Southern Africa's most important sources of energy, the formation of the Lake gave birth to a vibrant commercial fishing industry and a continuously developing tourism industry offering some of Africa's most breathtaking scenery with a diversity of fauna and flora, hotel accommodation, sports fishing, water sports, house boating and a variety of other tourist activities.

The building of the Dam Wall was not without its problems and its history dates back to the last decade of the 19 th century. During the 1890's the colonial government investigated the Kariba site as a potential crossing point for a railway bridge across the Zambezi River connecting the two British colonies Southern and Northern Rhodesia. However the difficulties encountered in constructing a railway through the Zambezi escarpment soon became apparent and the interest in Kariba changed from the construction of a bridge to the construction of a dam to provide hydro-power to the burgeoning mining and manufacturing industries. The period between 1920 and 1945 saw the discovery of copper in Northern Rhodesia and with the sharp increase in demand for copper and other minerals after World War II, both the mining and manufacturing industries in Northern and Southern Rhodesia grew rapidly. At that time, the copper mines in Northern Rhodesia were being supplied with electricity from a number of small coal-fired power stations situated on the Copperbelt and coal was being supplied from the Wankie coal fields in Southern Rhodesia and from South Africa . The large amounts of coal that were needed for these power stations were transported by rail, over distances exceeding 750km. The largely single-track railway line linking the Copperbelt with the Hwange Colliery proved incapable of coping with the increasing tonnages of coal and a new source of power had to be found.

Despite the long recognised hydroelectric potential of the Zambezi , the first move towards its use was only in 1946, through the formation of the Inter-territorial Hydroelectric Power Commission. This was followed in 1948 by the appointment of an advisory committee to decide upon the relative merits of the construction of two potential hydro-electric schemes on the Zambezi and Kafue rivers. Both these schemes were considered viable and needed in order to supply the every increasing demand for energy of the colonies. The committee initially recommended Kariba as the first scheme to be built, particularly in light of the inadequate hydrological information available for the Kafue, the irrigation potential of the Zambezi downstream of Kariba and the possibilities of fishery and other developments related to the formation of the lake. However, the larger and more costly Kariba scheme would take longer to construct and the power needs on the Copperbelt were becoming critical. Despite being British colonies, both Northern and Southern Rhodesia had autonomous governments with the North being considered as a protectorate or an “indirect rule” colony and the South being considered as a “settlement” colony. As a result, political differences were evident and a degree of mistrust emerged between the two governments. In view of the urgent need to satisfy the electricity demands of the Copperbelt, the Northern Rhodesian Government, influenced by the mining companies, was keen to see the development of the Kafue scheme first. It was confirmed that the Kafue scheme would be cheaper and that it could be constructed in two to three years, less time than Kariba. The Northern Rhodesian legislature decided in February 1953 to proceed with Kafue scheme and Kariba was almost put on the “back burner”. The political situation of the region became more complicated with the formation in August 1953 of the Federation of Rhodesia and Nyasaland (present day Malawi ) and the political wrangling over which site to develop first intensified. The intense debate over the site of the new hydro dam continued for almost 2 years with arguments ranging from under/overestimates of the potential of Kafue versus Kariba, the desire of the Federal Government to unite the two Rhodesia's and the political posturing of the two former Rhodesian governments. Eventually, the Federal Hydroelectric Board, which was established in May 1954, sought the advice of external experts. The consultant's report which again favoured Kariba as the best and most politically acceptable site was published in March 1955. The Federal Government accepted the consultants' advice and construction of the Kariba Dam began later that year.

The Kariba Dam project was originally planned to be constructed in 2 phases over a period of 15 years. Phase I being the construction of the Dam Wall and the South Bank Power Station and Phase II, planned to start in 1965, the construction of the North Bank Power Station. Phase I of the project was financed from a number of local and international sources, including the World Bank, the copper mining companies, commercial banks and other governmental institutions. Project costs for Phase I of the project were in the region of £78 million (approximately US$1.2 billion in 1998 money). Preparatory earthworks began in early 1956 and Phase I of the project was completed in 1960, ahead of schedule and below budget cost estimates. However, the construction phase was plagued with difficulties. The most significant of which were two consecutive years (1957 & 1958) of record flood levels of the Zambezi River . In 1957 the river flooded above normal levels in what was termed a 50 year flood. The following year the level of the river was 3 metres higher recording what was termed a 100 year flood. The foundations of the Dam Wall were flooded and the contractors had to retreat from the valley floor. Worked stopped on the Dam Wall for at least 3 months on each occasion until the flood levels subsided. The unprecedented floods of 1957 & 1958 led to a redesign of the Dam Wall. The wall itself was raised by 6 metres and an additional 2 flood gates were installed making 6 gates from the original design of 4 gates. It is interesting to ponder what might have happened if the decision to build Kariba was taken just 2 years earlier. The Dam Wall would have been built to its original design criteria not knowing what would happen when the river flooded at its peak. The consequences of not being able to control the flood waters on an already full dam would have been unthinkable. By the rainy season of 1959 progress on the Dam Wall had reached a stage where flooding was no longer a problem and at last the contractors had the Zambezi “by the throat”. The construction continued ever upwards until at last at the end of that year, the wall was finished.

The local Batonga tribe of the Zambezi Valley put the blame for the flooding squarely on their “River God” Nyaminyami, a Tonga spirit believed to be half snake and half fish. Legend has it that Nyaminyami's wife had gone downstream of the Kariva, now known as the Kariba gorge to answer the prayers of her people and bless them. When it was time for her to return to her husband, she could not cross because of the Dam Wall and this angered Nyaminyami. He consequently ordered the river to rise and destroy “the white man's bridge”.

During the planning stages of Kariba, little or no attention was paid to the social impact of its construction. During the colonial days, little regard was paid to the local “Bantu” population and particularly so in the sparsely populated rural areas. Nevertheless there were 57,000 Batonga people living in the Zambezi Valley that would be affected by the rising waters of the Lake . The Batonga, steeped in tradition and ancient tribal beliefs could not believe that the “white man's” wall could change the course of nature. For a long time they simply ignored the threat that the waters of the Zambezi would rise and take their land and their homes, thinking only that it was a plot by the government to steal their fertile lands by the river. The inevitable happened and the waters did rise, but still the Batonga refused to leave. In the end they had to concede defeat, and the people were loaded unceremoniously onto to trucks (often leaving their possessions and livestock behind) and were moved to higher ground. The costs of resettlement (which were not adequately budgeted for) had to be born by the Kariba Dam developers (the Federal Hydroelectric Board) but the responsibility for resettlement lay squarely in the hands of the respective Southern and Northern Rhodesian governments. Because the two colonies were independently governed and had different styles of government, the resettlement process on both sides of the Lake were very different. On the Northern side (now Zambia ) the people were at least compensated somewhat (albeit today considered inadequate) for their hardship. The physical cost of resettlement, compensation to the individuals moved; tribal compensation for hardship, inconvenience and loss of tribal lands and customary rights; compensation in respect of loss of earnings while clearing new lands at the rate of £5 per acre, allowing one acre per person; compensation for the lost earning while building new huts at the rate of £10 per hut; and compensation for the loss of crops was paid. However on the Southern side (now Zimbabwe ) food would be provided during the resettlement period and adult males would be exempted from the annual poll tax of £2 for two years. The Tonga Chiefs on the Zimbabwe side were told to go and find suitable land on the high ground as they would not be allowed to remain in the Zambezi Valley as this would be reserved for wildlife preservation.

On the Zambian side, people were moved to high ground but to a large extent they were allowed to remain close to the Lake shore. Most of the new land was of poor quality and easily erodable. Also, recession agriculture was not possible due to the far distance to the river and only one crop per year could be produced. The resettling of too many people, to areas too small to accommodate them, aggravated the problem. In the first years after resettlement, food production decreased and famine occurred. In later years many more problems occurred, caused by lack of water, breakdown of water wells and other basic infrastructure provided as part of the resettlement programme. During the first years after resettlement, the Tonga 's were allowed to freely cross the Lake and meet relatives and friends on the other side. However, the frequency of visits was no longer the same as before given the long distances involved, as some relatives were located more than 100km from the Lake . When the Federation of Rhodesia and Nyasaland broke up in 1963 and Zambia became an Independent Country in 1964, free movement between the tribe ceased to exist and border posts were established at Chirundu and Kariba. This meant that relatives and friends on the opposite side of the border lost contact with each other and their traditional customs and practices began to disappear. There were a few things, that were better than in pre-Kariba times, such as the access roads to the area, schools and medical facilities, but the many promises made by the government of the day were not kept, not even by the post colonial Zambian Government. There are inevitable winners and losers in a project of this kind. Clearly the people of Zambia as a whole have benefited from the construction of the Kariba Dam but equally clearly, the losers were the Batonga people - the “Valley people” who lost their ancestral homes, their land and customary beliefs. The Tonga 's today have readjusted to their new situation, many of whom have moved far away from the Valley too seek a better life. However, the injustices of the past are still a burning issue and need to be addressed. In Zambia , an initiative known as the Gwembe-Tonga Rehabilitation and Development Programme (supported by World Bank funds) has been put in place in an attempt to mitigate some of the long term effects of resettlement and improve the lives of the remaining Valley Tonga 's.

Zambia gained its Independence in October 1964 and relationships with Southern Rhodesia deteriorated from the point onwards. In 1965, Southern Rhodesia made a declaration of Unilateral Independence from Britain and it became an isolated “rebel” republic. Dealing with Rhodesia became politically unacceptable for Zambia and the progress on Phase II of Kariba, the construction of the North Bank Power Station, was delayed. Zambia needed additional power in order to feed its ever expanding mining industry in the Copperbelt and it was decided to proceed with the construction of the Kafue Gorge Power Station. Preliminary excavation works began on the Kafue project in July 1965 and the project was completed in 1973. In 1970 the struggle for the Independence of Zimbabwe began and a bitter 10 year war broke out between the “Southern Rhodesian Settlers” and the “African Nationalists”. For Zambia , despite having almost completed its second major hydro-power generation project at Kafue, the reliance on Rhodesia for access to power from the Kariba South Bank Power Station became politically “high risk”. Consequently it was decided to rejuvenate Phase II of the Kariba project and construction of the North Bank Power Station began in 1971. The construction of the North Bank Power Station was problematic and it took two years longer than expected to build at a cost 2.5 times the projected budget. There were many problems, including geological problems resulting in project redesign, contractor problems (the original contractor went into receivership), logistical problems in the procurement of the generating equipment, political problems encountered when the borders between Zambia and Rhodesia were closed and in 1973, the world price of oil began to increase causing rapidly escalating prices for heavy machinery internationally. Finally the Kariba North Bank Power Station was completed and the first commercial power generation started on in May 1976, 28 month later than planned and at a cost of US$420 million (in 1998 money).

During the construction of Phase I of the project the township built to house the building contractors and workforce was at Kariba on the South Bank (now Zimbabwe ). The town of Siavonga did not develop until the construction of Phase II – the building of the North Bank Power station. This delay, together with the “effective” closing of the Zambian side of the Lake during the Rhodesian/Zimbabwe war disadvantaged the development of Siavonga town. It is only during the last two decades that serious development has taken place in Siavonga. Today the town administered by its own local government and have most of the amenities available including a bank, post office, fuel stations, and shops. A thriving commercial Kapenta fishing industry has emerged together with a number of hotels and guesthouses catering for the conference and tourism markets. Other industries are also coming in to the town such as natural stone manufacturing and most recently the discovery of Uranium around Siavonga promises further development. Siavonga is a small yet actively developing town which is host to a variety of industries on the shores of one of Africa's most beautiful Lakes with the vision of becoming Zambia 's second most popular tourist destination.