Annual flooding of the Delta

Due to a combination of higher than normal Indian Ocean temperatures, a low pressure system centred over central Botswana, Zimbabwe and Zambia and a southward movement of the moist Inter Tropical Convergence Zone (ITCZ), the rains were above average during 2009.  This has been particularly so over the 16 and 17 Degrees South latitude in a band across the African Continent and which, fortuitously, include the catchments of most of the great rivers mentioned. 

During March 2009 this band received about 120% above average rainfall, followed by localized but heavy falls along the Zambia/Angola border region as well as over the Okavango Delta itself.  Above average heavy rain was also recorded in Central Zimbabwe and Zambia, also important catchment areas for the middle and lower Zambezi.

The flood effects in the Okavango and Linyanti will be fantastic, as large grassland areas and floodplains which have not been inundated for many years and even decades, become flooded, and a complete recharge of groundwater takes place.

Islands which have been dehydrated through no ground water flows will now rejuvenate and distal lakes such as Ngami and Mababe will fill.  These two terminal sinks along with a major increase in flows down the Boteti River,  which connects the Okavango to the Magadikgadi, create wide ranging habitats for many, many waterfowl and mammal species.

Linked to the Mababe Lake and fed from the Linyanti/Kwando system the Savute Channel can be expected to have a major increase in flows, which may well result in the re-establishment of the famed Savute Marsh at the Chobe National Park end of the channel, which has been dry since 1984.

On the 8th May 2009 Chris Worden flew along the Selinda Spillway, (that connects the North eastern arm of the Okavango Delta to the Savuti channel in the Linyanti region) and it was full of water along its entire length!
The availability of so much water over a large area will have extremely beneficial effects on the distribution of the region’s high elephant numbers.

Most, if not all of the camps in the Okavango are situated on islands and higher ground with many being on lifted walkways and stilts.  There should be little, if any, effect on the camps themselves, although some camps may have to adjust the road networks somewhat since many were located on lower ground during the dry years. (In the Okavango a meter can make a huge difference to wet and dry).

The Caprivi Strip, the section of Namibia that separates Botswana and Zambia and culminates in the four countries of Namibia, Zambia, Zimbabwe and Botswana joining together, was completely under water as the Zambezi pushed its waters back up the Chobe River, forcing the Chobe to flow backwards from East to West (if its normal the river flows from West to East).

This is in fact a natural phenomenon which only happens very occasionally in the wet and dry cycle as mentioned, and is a grand opportunity to see the waters of this fascinating region in all their glory. Already in the last two weeks the river levels of the Chobe and Zambezi have dropped 2 metres, exposing newly fertilised grasslands. The Okavango Delta continues to fill as the waters filter through the vast reed beds and papyrus.

The photograph below, taken from the NASA space station, shows the  regions’ rivers in full flood on 30th March, and the confluence of the Chobe and Zambezi a huge lake!

This is such a special year for us, so if you are planning to visit this region, it will happen only once in a lifetime, do think of joining us. NASA have some great images of the floods - follow this link NASA Earth Obvservatory to check it out. Be warned - images are huge and take a while to load!