The Barotse Floodplain, also known as the Bulozi Plain, Lyondo or the Zambezi Floodplain, is one of Africa's great wetlands, on the Zambezi River in the Western Province of Zambia. It is a designated Ramsar site, regarded as being of high conservation value.
The name recognises the floodplain as spawning the culture and way of life of the Lozi people, "Rotse" being a variant of Lozi, and "Ba" meaning "people". They became a powerful kingdom in Central/Southern Africa under their king or litunga Lewanika, whose realm extended up to 300 km from the plain and was called Barotseland.
Topography and area
The region is a flat plateau at an elevation of about 1000 m tilting very slightly to the south. The Zambezi and its headwaters rise on the higher ground to the north, which enjoys good rainfall (1400 mm annually) in a rainy season from October to May. A flood moves down the river reaching a flat region, formed from Kalahari sands, about five hundred kilometres across. To the south around the Ngonye Falls harder rock is found at the surface and has resisted the river's tendency to cut a channel down into it, and so acts a bit like a dam. Behind it the floodplain has formed. Below the falls the river falls nearly twice as fast as it does on the plain, and flows more swiftly in a narrower valley less prone to flooding.
The floodplain stretches from the Zambezi's confluence with the Kabompo and Lungwebungu Rivers in the north, to a point about 230 km south, above the Ngonye falls and south of Senanga. Along most of its length its width is over 30 km, reaching 50 km at the widest, just north of Mongu, principal town of the plain, situated at its edge. The main body of the plain covers about 5500 km², but the maximum flooded area is 10 750 km² when the floodplains of several tributaries are taken into account, such as the Luena Flats. The Barotse Floodplain is the second largest wetland in Zambia after the Lake Bangweulu system, which differs in having a large permanent lake and swamps, and a much smaller area which dries out annually.
The satellite photo was taken in April 2004 at the peak of the flood, Note that the northern part of the plain, near Lukulu, is less flooded, the land there varies a bit more in height and the water tends to keep to the many river channels.
Flood levels and timing
See also Climate of Zambia
The peak of the flood occurs on the floodplain about 3 months after the peak of the rainy season in January–February. The flood usually peaks in April, and recedes in May to July, when grasses quickly grow on the exposed plain. At the river's lowest water in November the floodplain still contains about 537 km² of lagoons, swamps and channels. The flood leaves behind a fertile grey to black soil overlaying the Kalahari sands, enriched by silt deposited by the flood as well as humus from vegetation killed by the initial flood, and from decaying aquatic plants left to dry out in the mud. It provides a good soil, but in the late dry season it bakes hard in the heat of the sun.
As the floods recede, water is left behind in lagoons, swamps, and oxbow lakes.
Natural environment
The floodplain is in the Zambezian flooded grasslands ecoregion, and is bordered by slightly higher sandy ground on which grow dry grasslands (Western Zambezian grasslands) with woodland savanna (Zambezian Baikiaea woodlands) to the east and south, and patches of evergreen forest (Cryptosepalum dry forests) in the north and east.
The flood provides aquatic habitats for fish such as tigerfish and bream, crocodiles, hippopotamus, waterbirds, fish-eating birds, and lechwe, the wading antelope. After the flood, the plain is a habitat for grazing animals such as wildebeest, zebra, tsessebe and small antelope such oribi and steenbok, and their predators. These herbivores have been displaced in most areas by the cattle grazed by the Lozi, but they have provided a large game reserve on the dry grassland to the west, the Liuwa Plain National Park, once the Litunga's hunting grounds, established as a game reserve by Lewanika in the 19th century. In addition the entire western of the Zambezi within the country is a Game Management Area.
Human ecology of the plain
About 250,000 people live on the plain with a similar number of cattle, migrating to grasslands at the edge of the floodplain when the flood arrives. The floodplain is one of the most productive areas for raising cattle in the country.