Zimbabwe: Lake Kariba (Part 2)

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Issue 9

Building Kariba dam was one of Africa's most ambitious hydro-electric projects. Here's how it was done. Damming the Zambezi Building Kariba dam was one of Africa's most ambitious hydro-electric projects. Here's how it was done. 1. Low water seasons, 1955 and 1956. From the north (now Zambian) bank, a thin arch coffer dam was erected and a diverting channel was dug to and from it. Excavation of the 3,470ft long, 40ft high and 33ft wide south bank diversion tunnel through solid rock took place and piers for the road bridge across Kariba Gorge were put in position. 2. High water season 1956-1957 Inside the coffer dam, block sections of the main wall (with temporary openings left in them) were erected. Building of the south bank section above the water line was started and the downstream road and suspension bridges were completed across Africa's 4th largest river. In March 1957 the Zambezi rose at a record rate of 18ft per day with a peak flash flood on one occasion of 35ft. This delayed work for a while. 3. Low water season 1957. The north bank coffer dam was shattered with the biggest explosive charge ever set off in Africa. This allowed the river to flow down the diverting channel and through the temporary openings in the main wall. Rock fill was dumped from the bridge to block the main stream and cause the river to back up and flow either down the diversion tunnel or through the diverting channel and temporary openings. 380ft-arch coffer dams were constructed across the main stream and the water pumped out. The foundations for the wall footings in the steep-sided gorge were excavated on both banks. Work started on erecting the platforms for the Blondin cables that would ferry the concrete and materials from banks to work sites. 4. Late 1957 to June 1959. Building of the main wall block sections began. Some sections were left low to allow floodwaters free flow. In February and March 1958 even greater floodwaters blasted down the gorge. 20ft waves breached the main coffer dam and took both bridges away leaving only the Blondin cables crossing the gorge. When the flood subsided, work resumed, the wall was raised and the temporary openings and diversion tunnels were closed. The last skip of the 3,000,000 tons of concrete was poured on 22 June 1959. The waters began rising, eventually to form the 20,000 sq. miles lake behind the 1,900ft long, 420ft-high concrete arch. By 1990 the total electrical output had been raised to 1,350MW and was carried by over 3,000 pylons to industries in Zimbabwe and Zambia. Operation Noah - The Fight to Save Kariba's Wildlife Kariba's rising waters put the lives of thousands of animals in danger. This prompted the most extensive and courageous rescue operation ever undertaken. As the dam wall closed and the waters rose, milliards of large crickets, rats, mice and the like emerged and scurried away from the encroaching waters. The skies above were blackened by swarms of birds sating themselves on the harvest. In the water the voracious tiger fish rampaged and, glutted with drowning insects, died. Many animals, notably the larger carnivores, retreated inland. Others, however, instinctively made for high ground to wait out another seasonal flood, and were trapped on temporary islands created by the unrelenting upsurge as Lake Kariba filled. Senior ranger Rupert Fothergill, Frank Junor (a young scientist), Brian Hughes (an ex-fireman who could not swim) and their assistants arrived. Under-manned and under-equipped, Operation Noah had begun. They began by trying to manoeuvre large animals into the water and shepherding them to safety. In so doing it was revealed that many mammals could swim considerable distances-waterbuck a mile and baboon 400 yards, for instance. They also discovered that hornless, female buck could paddle further than males. And they observed instances of intelligent, adaptive behaviour such as waterbuck ferrying offspring on their backs and large horned bull antelope supporting their heads on logs, or resting them on others' backs, during their journey to safety. Others, declining the swim, were driven into the water for easier capture before being trussed and transported to shore. During this time tranquilliser darting techniques were pioneered. This was a heroic period, when a handful of men drove themselves to the verge of collapse whilst their gains were pathetically small as thousands of animals drowned or died from shock or injuries sustained during rescue operations. Through the British Sunday Mail (February 15, 1959) the story of Operation Noah fired the sentimental imagination of the world. Soon there were more feature writers, television cameramen, do-gooders and inquisitive officials than there were designated rescuers and their intrusion severely hampered operations. A request for old nylon stockings to plait as replacements for ropes which burnt captured animals, saw millions of pairs inundate the local SPCA in another unstoppable flood. Provoked by the pressures of a press-fed public and humanitarian organisations, the task force was increased and better equipped by the Southern Rhodesia government. Overseas financial aid was refused, however, because of the danger of donors deeming it their right to intervene in operations. These funds were diverted to Northern Rhodesia (now Zambia) and used to launch their participation in the rescue campaign. Operation Noah, the largest animal rescue exercise ever undertaken, saved over 5,000 animals, including 50 Black rhino, between 1960 and 1962. How many creatures died will never be known. Ironically, in the 12 years up to then, over 300,000 animals had been killed as part of the programme to control the spread of tsetse fly in Southern Rhodesia. Further Reading: Fothergill, Bridging a Conservation Era, by Keith Meadows (Thorntree Press). From Top to Bottom Scenes from Operation Noah, May 1959 · With considerable caution, a warthog is disentangled from the net. · The game rescue teams set up nets across a narrow part of an island and then drove the game into these, secured them, then either swam or carried the net and animal to the mainland. In this picture, the nets were being carried ashore from the boat, ready to release the animals. &middotA kudu being shepherded to the mainland, having to swim nearly two miles. · A herd of eight waterbuck are driven to safety on the mainland, one and a half miles from the island they were on. Since they were large animals and powerful swimmers, no attempt was made to capture them, but they were kept on course by the boats. One doe had a calf which rested its front legs on her back for the entire journey. Another doe which tired was assisted by the ram, on the right of the picture, which swam in tandem with it. The animals came to safety on the Zambian bank. Triassic Valley The discovery of numerous fossils on the lakeshore has proven that the area is of tremendous palaeontological interest-for scientists and tourists alike. About 360 - 400 million years ago a very early type of fish, with muscular fins and shell-crushing jaw plates studded with small enamelled teeth, drew a lung full of oxygen through its gills, exhaled, expired and was interred. A couple of years ago Steve Edwards carefully exhumed it-or, more precisely, that lungfish's dental palate. A safari guide by profession, he stumbled on the find while on a walking safari in the Matusadona National Park, not far from his safari camp on the Kariba shoreline. This finding, together with that of other Devonian age creatures, indicates that, about that time, shallow seas flooded much of southern Africa. It was also about then that several major advances in the evolution of life took place. Sponges, corals, bi-valved molluscs, brachiopods and other aquatic invertebrates began developing. Tree forms emerged-giant ferns, which rose up 40ft, formed forests with an undergrowth of primitive plants and fungi. Not exactly the "Big Five" country found today! These prehistoric Lungfish (Ceratodus) or Dipnoi gave rise to the amphibians which ventured out of the lakes and seas and onto land to establish the ancestors of all prehistoric and modern land-dwelling animals-as well as the relatively unchanged Lung fish of today. Now with a strong interest in the palaeontological and archaeological riches of the Zambezi valley, Edwards has also 'extracted' teeth and bone fragments of several other pre-dinosaur reptiles-those known scientifically as the (socket-toothed) Thecodont, the Prosauropod, the Phytosaurs and the Cabyrinthodont (a large amphibian). These creatures lived during the Triassic period, between 200 - 300 million years ago, when cycads and conifers were becoming increasingly abundant in the evolution of forests. It was about this time that some reptiles began to change from the sprawling crocodile-like gait to walk more upright on hind legs, whilst using their long tails for balance. Most were small - one to eight feet in length. Several species adapted to living in the sea whilst others roamed over the upper part of the recently-formed terrestrial karoo beds and adjacent areas, including present day Zambia. However, for the conical toothed Phytosaurs which, like the Nile crocodile of today, lurked in rivers and ambushed unwary drinkers, the nearest geographical records are from North Africa and Madagascar. Scientists at the Natural History Museum in London have authenticated Edwards' findings and many visitors have beenimpressed when visiting the dinosaur site. It's an aspect of the lake most people don't expect to encounter. Kariba is famous for its "own" dinosaur, the 20-foot saurischian, Vulcanodon Karibaensis, which roamed the valley floor some 200 million years ago. Discovered on an island in July 1969, it was excavated in 1970 - 1971 by members of the palaeantological department of the University of Zimbabwe. It was new to science and as a result linked by name to its home, Kariba. The Displaced People In 1956 the Gwembe Trough, a tract of inhospitable country that stretched either side of the Zambezi River from Devil's Gorge to Kariwa Gorge, was home to about 50,000 Batonga tribesmen. Here, largely isolated from civilisation, they had been free to fish, hunt, grow crops, practise animal husbandry, barter ivory and skins for beads and salt, follow age-old traditions and visit relations across the life-giving river. The building of Kariba dam was to force an unwelcome change. The impending submersion of their lands and the need to move to higher ground was broken to them at lengthy indabas (meetings). Incredulous, they warned that Nyaminyami, their river deity, would destroy the puny "bridge" at Kariwa, a thesis which gained credibility with the unprecedented floods that did great damage to early construction work. Resentment at being moved from their ancestral lands was understandably high, particularly among the 30,000 living north of the river. In the then Southern Rhodesia, explanations, lengthy discussions and visits by elders to their new two million-acre homelands led to an unhappy acceptance of the inevitable and agreements on procedures. Hundreds of miles of roads,† schools and clinics were built, streams were dammed and boreholes sunk in preparation. Before villages were evacuated spirits had to be appeased. The procedure varied but most often a ceremonial beer drink was held on the eve of departure. During this, explanations, reasons and reassurances were given to ancestors. Appropriate bushes were dragged behind transport vehicles to satisfy the belief that this would enable guardians to retain contact with ancestral spirits below ground whilst moving. The trucks began to roll in late 1956, with the operation soon becoming routine and the final groups of the 20,000 southern bank Batonga resettled in similarly remote, but more desolate, lands above and back from the new waterline, by early 1958. During the first year of settlement, rations, skills training and material aid were given and doubting Thomases taken back to verify the lake's encroachment. In Northern Rhodesia, things did not go well. Tribesmen clashed voilently with the authorities. Eight Batonga died and 32 were injured. Relocation was delayed until the waters rose and tempers cooled, but outbreaks of dysentery and other diseases in the new homelands caused more deaths and more resentment. Some resisted eviction right to the bitter end - literally. One spirit medium was plucked from a rapidly disappearing hilltop as he sat, Canute-like, defiant to the last. With his departure an ancient culture lay submerged beneath the waters of progress. Kariba Town The advent of Kariba dam saw the development of the town of the same name, a settlement spreading over the hills at the lake's eastern end. he steep, winding road to Kariba follows old elephant paths that descend through the Brachystegia woodlands of the Zambezi escarpment. The town takes its name from the Shona word "Kariwa" meaning trap, an apt description of the narrow gorge in which the dam wall now harnesses the power-generating might of the Zambezi. Kariba town is an unfocused two-level jumble that sprawls along and above about 10km of hilly eastern lakeside. Hotels and campsites are spread among the bays while Mahombekombe, a low-cost housing township, creeps up Sugar-loaf Hill in a desire to escape the commercial fishing harbour and ever-busy bus terminus. Originally built to house dam wall construction workers, this township is now home to fishermen, tourist industry workers and lower-income people marketing produce, products and themselves with as much enthusiasm as the 40oC+ summer temperatures will allow. Perched uphill, Kariba Heights is a far cooler and more prestigious neighbourhood, where air-conditioned residences and a country club are served by a shopping precinct. One feature is the circular open-sided Catholic church of St Barbara, which shelters five Carrara marble statues of saints and a plaque in memory of the 86 Italian workers who died during the construction of the wall. There is also a monument to Operation Noah-the saving of animals marooned by the rising waters of the lake. Observation Point looks down upon the 128m-high, 579m-wide concrete dam wall. From the craft shop, Nyaminyami (river god) walking sticks and crocheted bedspreads and tablecloths regularly leave with visitors who haven't already purchased the same from the Shell garage kiosk on the main road below. The ferry to Mlibizi at the western end of the lake, sunset launch cruises, pleasure craft and transport to lodges and camps around the lake, set sail from various lakeside marinas. Watch out for elephant, buffalo and other beasts that occasionally stroll into town, the hippo and numerous crocodilesever present along the shores and the unseen bilharzia snails lurking in stiller waters. Accommodation |Outside of Kariba town there are few camp sites or cheap chalets, besides the fishing association camps or the self-catering lodges and camps run by the Department of National Parks at Tashinga and Sanyati. In Kariba town, however, there are numerous private houses for rent at good rates, and most hotels offer extremely good value in the middle budget price range. The private safari lodges which are located around the southern lake shore offer a more intimate experience: high quality accommodation, all-inclusive rates, all activities and quality food. Even within these, the price range does vary, as does the level of exclusivity: some lodges only sleep eight people. Others-Bumi Hills and Katete, for example-are larger. Given the choice you have to work with, it is best to gather more information to decide which will best suit your tastes and budget. Most transfers to the lodges are by boat or air. There are landing strips at Kariba and Bumi. Air Zambezi operates daily flights between the two and air charters are provided by a variety of companies. Published in Travel Africa Edition Nine: Autumn 1999 Text is subject to Worldwide Copyright (c)

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