The Okavango Delta in Botswana, in the middle of Southern Africa, is a unique pulsing wetland. There are two distinct areas – the permanent swamp, which is inundated with water all year round, and the seasonal swamp which is flooded annually and dries gradually with the onset of summer.
Almost
95% of the water in the Delta originates from the summer rainfall
(January – February) catchment areas in Angola, about 1,000km
north-west of Botswana. From Angola, the water flows south mainly
with the Cubango river from the west, and the Cuito river from the
east, across the border into Namibia. It comes together as the
Okavango river in the Zambezi Region (formerly known as the Caprivi
strip) before it reaches Botswana at the Mohembo border post.The average size of the Okavango river as it enters Botswana is 200 metres wide and four metres deep. The length of the Okavango river from its source in the Angola highlands to the mouth at the outer margin of the Delta in Botswana is 1,100 kilometres. The first stretch of approximately 75 kilometers of the river in Botswana is called the Panhandle due to its shape. The Okavango river is the only perennial river in Africa that flows eastward without reaching the ocean. It empties its water into the thirsty Kalahari sands forming a great inland fan of channels and swampland - the Okavango Delta, an oasis in the deep expanse of the Kalahari Desert.
Chief’s
Island, the largest island in the Delta, was formed by a seismic fault line which
uplifted an area over 70 km long and 15 km wide.
Historically it was reserved as an exclusive hunting area for the
local community’s chief. It now provides the core area for much of
the resident wildlife when the waters rise.
The
watercourses are constantly changing due to annual flooding as well
as a combination of sediment transport, seismic activity, the
construction of termite mounds, the continual opening up of new
channels by feeding hippopotami and the closing of others by new
vegetation growth.
By
the time the water reaches the town of Maun at the Delta’s southern
fringes, its volume is a fraction of what it was. As little as two to
three percent of the water reaches the Thamalakane River in Maun,
over 95 percent lost to plant transpiration and evaporation. The
remainder may continue east to the Boteti River, to fill Lake Xau or
the Makgadikgadi Pans, or drain west to Lake River to fill Lake
Ngami.
The
Okavango Delta can vary in size from 15,000 square kilometres during
drier periods to a staggering 22,000 square kilometres during wetter
periods. Its dominant plant species are reeds, papyrus, mokolwane
palms, wild date palms, acacia, sycamore fig, sausage trees,
raintrees and lagoons covered with floating waterlillies.
Of
international importance
The
Okavango Delta was declared a wetland of international importance and
received its Ramsar status on 12 Sep 1996. The Ramsar boundaries
encompasses the Okavango Delta (including Moremi Game Reserve),
Tsodilo Hills, the Kwando-Linyanti River system and Lake Ngami. This
is an area of more than 55,000 square kilometers (or 5,5 million
hectares), making it by far the biggest Ramsar wetland in Southern
Africa and the 3rd
largest in the world.
It
is Botswana’s only Ramsar wetland and qualified on several of the
required criteria.
Firstly,
it is a unique inland wetland providing a haven for many endangered
species of flora and fauna. This includes globally threatened bird
species such as the Wattled Crane, the Slaty Egret (most important
breeding site), Lesser Kestrel, Corncrake and the Black-winged
Pratincole.
More
than 500 species of birds have been identified in the Okavango Delta
with much more than 20,000 water birds occuring in the Delta at any
time.
The
Okavango Delta also supports more than 1% of the global population of
several bird species including African Skimmer, African Pygmy-Goose,
White-backed Duck, Fulvous Duck, African Spoonbill, Marabou,
Saddle-billed Stork, Squacco Heron, Black Heron, Little Egret, Great
White Pelican.
The
permanent swamps provide habitats for three species of aquatic or
semi-aquatic large mammals, all of which fall under the IUCN Red
List: Hippopotamus, Sitatunga and Red lechwe, the most populous large
mammal in the Delta. It is also a stronghold for the Nile crocodile.
Large
herbivores that utilize the higher dry land masses found within the
Okavango Delta and the riverfronts of the Linyanti and Kwando include
the African Buffalo, Plains Zebra, African Elephant, Blue Wildebeest,
Tsessebe, Southern Reedbucks, Bushbuck, Puku Antelope, Impala,
Waterbuck.
Elephants, Zebras and Wildebeest migrate on a seasonal basis between temporal wetlands in northern Botswana and the permanent wetland systems of the Delta, making it an important refuge during the migration cycle.
One
of the largest remaining populations of the African Wild Dog roams
the islands in the Delta.
Papyrus and reed rafts make up a large part of the Okavango's vegetation. During the flood season they float well above the sandy river bed with roots dangling free in the water. This gap between bed and roots is utilised as shelter by crocodiles.
The
plants of the Delta play an important role in providing cohesion for
the sand. In the Delta, because of the clean waters of the Okavango, the river’s load consists almost entirely of sand. The plants
capture the sand and in the process create further islands on which
more plants can take root.
Land ownership and management
Land ownership and management
The
land within the Ramsar boundaries of the Okavango Delta is shared by
the local communities (95%) and the government of Botswana (5%).
The
management involves central government departments, district
authorities and the private sector. Direct responsibilities lie
within the following six ministries:
-
Ministry of Environment, Wildlife and Tourism
-
Ministry of Lands and Housing
-
Ministry of Agriculture
-
Ministry of Minerals, Energy and Water Resources
-
Ministry of Labour and Home Affairs
-
Ministry of Local Government
Threats
Several
potential threats create challenges for the Botswana government and
the management authorities of the Ramsar wetland:
-
Climate change in Southern Africa will result in a decrease of rainfall and increase in temperature in the longer term, leading to reduced water flows and high evaporation rates. This will potentially have the greatest impact on the Delta.
-
The Delta area is tectonically active. Earthquakes of the same magnitude as the one that occurred in Maun during 1954 (6.4 on the Richter scale) could cause major damage to the modern building structures of the town and may also accelerate the river channels and flood distribution in the Delta.
-
Upstream irrigation plans in Namibia and especially Angola are predicted to have a significant impact.
-
Agricultural discharges into the river such as nitrogen, phosphorus, pesticides and herbicides is a potential source of pollution.
-
The presence of a relatively large number of tourist camps and lodges is a potential pollution issue. To combat this, the Government of Botswana has adopted a low volume, high cost tourism policy that has limited the number of tourists visiting the Delta.
-
A major pollution issue is the spraying of tsetse flies. The possible negative side effects of this control measure have led to controversy among environmentalists, tourism operators, the local population and Government Institutions.
The
major tourist attractions in the Delta and the dryland areas are game
viewing and birding. With more than 122 species of mammals, 71
species of fish, 500 species of birds, 64 species of reptiles and
1300 species of flowering plants, the diversity and numbers are
staggering.
Tourists
visiting the Delta can do so by staying in one of the many camps and
lodges, or do a mobile boat safari into the Delta with one of the
operators. The Okavango Delta features some of Africa’s premier
camps and lodges such as the exclusive, upmarket Mombo
Camp on Chief’s Island.
Game
viewing is normally undertaken by walking, by 4-wheel drive vehicles
and by boats.
Lagoons,
lush waterways, floodplains, fast and slow moving waters provide a
haven for bird species and can best be seen from boats. Bird life is
at its peak during spring and summer months (October to March).
There
are a number of safari camps and lodges which offer fishing as part
of the tourist packages. The most popular recreational fishing
species is the tiger fish which is the world’s largest fresh water
fighting fish.
Mekoro (or Makoro or Mokoro) is a type of canoe made from tree trunks. It is very popular as a transport method in the Delta. Most camps and lodges offer Mekoro trails with a guide.
Special
The
Okavango Delta forms part of one of the world’s largest Ramsar
wetlands. It also became the 1000th World Heritage site on 22 June
2014. In addition, it is considered as one of the Seven Natural
Wonders of Africa which were officially declared on 11 February 2013
in Tanzania.
Date
of visit: 12 to 18 June 2016