May/June 2010 Flooding in northern Botswana
Flooding is taking place over a large area of the Okavango delta as well as in other areas. Experts believe the current water levels of the rivers are expected to rise by a further 100mm, which could result in further widespread damage to property and farmlands. This picture was taken near Seronga, where floodwaters have already isolated settlements and displaced families. Several homes have been inundated or destroyed and many safari lodge airstrips and bush roads are not passable.
The rainfall has been well above average – as of the end of April there was 850mm recorded with the normal yearly average being just over 450mm. Flow rates at Mohembo, on the Botswana-Namibia border, are over 1 000 cubic metres per second – an incredible late season spike and pushing water levels to higher than in 2009. A big flood was forecast for months as heavy rains in the Angolan highlands resulted in record water levels in all rivers. In the Okavango delta, safari lodges and camps are isolated as roads and airstrips have become impassable. In some villages, huts have collapsed (pictured at the end of this article) and residents moved to higher ground.
Flooding near Seronga, Botswan - Photo by Klaas Boll
This is one of many scenes repeated throughout the Okavango delta and other parts of Ngamiland as water surges into the region.
Botswana Floods – From the Birdlife Perspective
The following information is from the Birdlife Botswana Newsletter – please click on the link to visit their site:
EDITORIAL
One of the challenges of conserving birds in a semi-arid country like Botswana is that
many species, especially waterbirds, are highly nomadic and mobile, and react to the
occurrence of locally favourable habitat conditions. Thus it is that waterbird numbers in
Botswana have recently burgeoned with the return of high flood levels in the major
rivers in the northern part of the country, and the increased extent of flooding.
The Zambezi and Kwando-Linyanti systems attained the highest flood levels on record,
rejuvenating the Chobe floodplains, Linyanti Swamps, Lake Liambezi and the long-dry
Savuti Channel (water flow stopped a few kilometres short of the Savuti Marsh in
Chobe National Park). The Okavango River reached the highest flood level since 1959,
with the Delta virtually doubling in size and the distal distributaries penetrating
hundreds of kilometres into the dry fringing Kalahari areas – for example, the Boteti
River reached Rakops, over 200 kilometres south of Maun. The southern part of the
Mababe Depression flooded for the first time in decades, and Lake Ngami filled to over
115 km2(compared to 50 km2 in recent years).
The abundance of water created suitable waterfowl habitat and attracted waterbirds
from all over Southern Africa. However, more importantly, new breeding colonies of
herons, egrets, storks and other birds were created, boosting the numbers of these
species far beyond what could be achieved by any human-initiated conservation
measures. Even dryland species like sandgrouse are thought to have benefited from the
opening up of traditional breeding areas within flying distance of the Boteti River.
This is wonderful for the birds, but ironically poses unexpected challenges for BirdLife
Botswana: Important Bird Areas such as Lake Ngami will wax and wane with these
cycles in waterflow, masking changes in bird numbers due to anthropogenic threats;
places like Lake Xau (currently dry) might qualify sporadically as IBAs when water is
present; avi-tourism businesses conducted by Site Support Groups might crash as the
ephemeral waterbodies evaporate. This does not mean to say that we are unhappy with
the return of the higher flood levels – water is life in Botswana – we just need to adjust
our activities, and our thinking, to accommodate these fluctuations. We look forward to
the 2010 floods with keen anticipation.
Pete Hancock