The Okavango Swamp
water sources is mainly the Okavango River, as
well as some other tributaries and small rivers, and even a small
amount of the water comes from precipitation. The Okavango
River
arises in the Angolan Highlands. These interior highlands
have a mild climate with a rainy season from November through April
followed by a cool dry season from May to October. Elevations generally
range from 3,000 to 6,000 feet (900 to 1,800 m). Angolan
highlands have an average rainfall of between 1,200 and 2,000mm per
year, compared to around 400-600mm in the Okavango. As the
river flows
south from Angola, through Namibia, eventually into Botswana and into
the Okavango Swamp, some 11 million cubic meters of water flow each
year, draining through a maze of lagoons, channels, and islands before
disappearing into the Kalahari Desert.
From the Highlands in Angola, the Okavango River is known as the Cubango River, passing through the Caprivi Strip of Namibia and eventually reaching Botswana. The Okavango River drops four meters in a series of rapids known as Popa Falls. From here, the river flows either into the Okavango Delta region or flows into Lake Ngami. Lake Ngami was once described by David Livingstone as a "shimmering lake, some 80 miles long and 20 wide", and although the lake has dramatically diminished in size, it is still a vital habitat for wildlife and birds.
The most important feature of the Okavango River is its seasonal flooding, which commences in mid-summer in the north and ends six-months later in the south. This results in a cyclic motion of water rising in the north as it recedes in the south during summer, and a rising in the south as it drops in the north during winter. The ever changing landscape of the Okavango Swamp is a signature that is particularly pronounced in the central regions of the swamp. The swamp is divided into two regions: a permanently flooded zone in the north and a seasonally flooded zone in the south. The northern flood zone includes the panhandle with riverine forest fringes which is adjacent to the Kalahari woodlands and a vast wetland of islands, reed beds, channels, forest banks, and permanent water ways; whereas the southern seasonal flood zone has large Kalahari sand-veld islands with dry and deciduous woodlands fringed by wide grassy floodplains. The southern flood zone is more heavily influenced by the seasonal floods, whereas the north has less variability in the water levels. The seasonal cycling of the delta is hugely influenced by the rain patterns in the Angolan Highlands. But, as the waters reach the swamp and spread out, it evaporates and approximately 95% of the water that surged into the Panhandle evaporated into the dry atmosphere and another 2% is lost in the sands of the Kalahari. By July, only about 2 to 3% of the water that emerged from the Angolan Highlands passes Mun and enters the Thamalakane River, through the Boteti and Nhabe Rivers. During, poor flood years, the Boteti rarely rises above a trickle and the Nhabe remains dry. This has been the case for the last 20 years.
The Okavango Swamps water levels are lowest during the rainy season between November and March--thus limiting access to the inner-most reaches of the swamp. The flow peaks in the Panhandle in April and May, while the Chief Islands and Inner Delta are at their peak levels from late May to late June. The Eastern Delta receives its greatest volume of water from late June to late July, but is significantly affect by poor flood years.
From the Highlands in Angola, the Okavango River is known as the Cubango River, passing through the Caprivi Strip of Namibia and eventually reaching Botswana. The Okavango River drops four meters in a series of rapids known as Popa Falls. From here, the river flows either into the Okavango Delta region or flows into Lake Ngami. Lake Ngami was once described by David Livingstone as a "shimmering lake, some 80 miles long and 20 wide", and although the lake has dramatically diminished in size, it is still a vital habitat for wildlife and birds.
The most important feature of the Okavango River is its seasonal flooding, which commences in mid-summer in the north and ends six-months later in the south. This results in a cyclic motion of water rising in the north as it recedes in the south during summer, and a rising in the south as it drops in the north during winter. The ever changing landscape of the Okavango Swamp is a signature that is particularly pronounced in the central regions of the swamp. The swamp is divided into two regions: a permanently flooded zone in the north and a seasonally flooded zone in the south. The northern flood zone includes the panhandle with riverine forest fringes which is adjacent to the Kalahari woodlands and a vast wetland of islands, reed beds, channels, forest banks, and permanent water ways; whereas the southern seasonal flood zone has large Kalahari sand-veld islands with dry and deciduous woodlands fringed by wide grassy floodplains. The southern flood zone is more heavily influenced by the seasonal floods, whereas the north has less variability in the water levels. The seasonal cycling of the delta is hugely influenced by the rain patterns in the Angolan Highlands. But, as the waters reach the swamp and spread out, it evaporates and approximately 95% of the water that surged into the Panhandle evaporated into the dry atmosphere and another 2% is lost in the sands of the Kalahari. By July, only about 2 to 3% of the water that emerged from the Angolan Highlands passes Mun and enters the Thamalakane River, through the Boteti and Nhabe Rivers. During, poor flood years, the Boteti rarely rises above a trickle and the Nhabe remains dry. This has been the case for the last 20 years.
The Okavango Swamps water levels are lowest during the rainy season between November and March--thus limiting access to the inner-most reaches of the swamp. The flow peaks in the Panhandle in April and May, while the Chief Islands and Inner Delta are at their peak levels from late May to late June. The Eastern Delta receives its greatest volume of water from late June to late July, but is significantly affect by poor flood years.