Long-term climate impact on the Lake Victoria region influences water level fluctuation and resource availability

Historical climate parameters of the Tanzania part of the Lake Victoria region were studied focusing on rainfall variations and the lake water level. This study was prompted by the recent lake water recession after the big water level change which was observed in 1960s. Recorded rainfall pattern of the region was analysed for establishing their linkages to the changing lake environment. Similarly, community understanding of the observed changes in relation to climatic changes in the region was explored for comparison with recorded meteorological information for the past three decades from 1976–2005. It is presented that the region experiences an East-West rainfall pattern variation. The variations of rainfall relative to monthly average values indicated highest positive anomalies (529 mm) in March but this was during the second decade (1986 -1995) with lowest value (149 mm) during wet season. However the last decade (1996 -2005) had the highest anomaly value (∼361 mm). Generally decade 1 and 3 showed higher rainfall availability than decade 2. These results implied linkage between rainfall variations with Lake water level. In addition, the observation was supported by the model prediction which indicated past (1961–2000) and future (2045–2065) trends of the regional rainfall pattern to be in a varying trends. The variation of rainfall is shown to affect all livelihood systems for communities in the region. Like in the past, the Lake Victoria region should expect similar changes of the water level which now increasingly brings about serious impact to their livelihood.