LAKE VICTORIA BASIN
Dominant wind patterns in the Lake Victoria basin
KENYA
Lake Albert
Lake Kyoga Victoria Nile
Kitale
DEMOCRATIC REPUBIC OF THE CONGO
Mbale
Lake Baringo
UGANDA
Eldoret
Jinja
Kampala
Kakamega
Lake Wamala
Lake Bogoria
Kisumu
Nzola
Lake George
Entebbe
Nakuru
Lake Edward
Lake Kachira
Sondu
Mbarara
Lake Kyanebalola
Lake Victoria
Lake Naivasha
Nairobi
Bukoba
Lake Ikimba
Musoma
Ruhengeri
Mara
Lake Kivu
RWANDA
Kigali
Kibungo
Kibuye
Gitarama
Lake Burigi
Mbalageti
Mwanza
Butare
Simiyu
Ngozi
BURUNDI
Gitega
Bujumbura
Dominant winds:
Lake Victoria basin
Capitals Other cities Major settlements
January - February June - September October - December March - May
100 km
TANZANIA
Lake Tangayika
More than 25 000 inhabitants
Copyright©2016GRID-Arendal (LeviWesterveld) ·Cartografare ilpresente/NievesLópez Izquierdo
Figure 1.3: Seasonal wind patterns for the Lake Victoria Basin Source: Lake Victoria Basin Commission 2002
The hydrological processes of the Basin are influenced by seasonal winds, as depicted in Figure 1.3. During January and February and from June to September, the wind is predominantly from the east, blowing parallel to the equator. These relatively dry winds pick up moisture while crossing the Lake and deposit it in the western catchments, particularly the Bukora Catchment in Uganda. Between March and May and from October to December, the wind pattern changes towards the northern parts of the Lake (Lake Victoria Basin Commission 2002). Geology and Soils The LVB is geologically relatively young, formed through tectonic forces over 400,000 years ago (Yisong et al. 2004; Johnson et al. 2000). Most of the Lake Basin is made up of Precambrian bedrock, with the exception of the Kavirondo Gulf in the north-eastern corner. Tertiary and recent alkali volcanic and sedimentary units dominate the terrain. The nature of the land drained upstream affects the physical chemistry of the water: the majority of the rocks (mentioned above) are rich in silicates, aluminium and iron (Yisong et al. 2004; Johnson et al. 2000).
The Basin is characterized by different types of soils suitable for a variety of crops, including maize, beans, cassava and sugarcane. Ferrosols – characterized by high acidity and low base saturation – are dominant within the lower parts of the Basin. Vertisols, which are also common, are dark-coloured clays that expand and contract markedly with changes in moisture content and develop deep drying cracks. The vertisols soils are extensively cultivated. Drainage The LVB consists of rivers, streams and wetlands. The Kagera River provides the largest inflow into the Lake, contributing up to 33 per cent of surface water inflow. It originates in Rwanda and Burundi (as the River Akagera), as well as in parts of south-western Uganda, before passing through Tanzania. The other major rivers flowing into Lake Victoria are the Bukora and Katonga, which originate in Uganda; the Nzoia, Sio, Mara, Yala, Awach, Gucha, Migori and Sondu, which originate in Kenya; and the Mori, Simiyu, Grumeti, Mbalageti and Magogo-Moame, which originate in Tanzania (Lake Victoria Basin Commission 2007a) (Figure 1.4 and Table 1.2).
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