LAKE VICTORIA BASIN

Rainfall is the primary source of water recharge for the

LVB, contributing 80 per cent of the water entering the

Lake (Awange et al. 2008). The main water reservoirs in

the Basin include surface water in lakes, rivers, streams

and wetlands, and groundwater in aquifers.

There is considerable variation in the intensity and

spatial distribution of rainfall across the Basin. This is

demonstrated by the study conducted in Kericho, Kabale

and Bukoba (Kizza et al. 2009). The annual precipitation

cycle in Bukoba and Kabale, as much as the rest of the LVB,

shows two distinct rainy seasons: the March to May rainy

season, and the September to December rainy season. The

rainy seasons are punctuated by two dry seasons between

January and February, and between June and August

(Kizza et al. 2009). The September to December period

receives less rainfall than the March to May season.

The daily, seasonal and inter-annual variability of LVB’s

climate results from the interaction between the inter-

tropical convergence zone (ITCZ), El Nino/Southern

Oscillation (ENSO), Quasi- biennial Oscillation (QBO),

large-scale monsoonal winds, meso-scale circulations

and extra-tropical weather systems (Nicholson and Yin

2002). The seasonal north to south movement of the

ITCZ results in the two rainfall seasons, while the inter-

annual variability in received rainfall corresponds to the

ENSO changes (Kizza et al. 2009).

The study by Kizza et al. (2009) further indicates an

overall increase in the average rainfall amounts in the

LVB. There is, however, some variation across the region:

while there has been a general increase in the average

annual rainfall in the western sections of the Basin,

some stations in the eastern section recorded a decline.

Rainy day at Lake Bunyonyi in Kabale, Uganda

Lake Ruhondo in the Kagera sub-basin, Rwanda