This study investigates the potential effects of climate change on the
hydrology of Ssezibwa catchment in Uganda. The study employs
statistical downscaling techniques, which have of recent proved useful in
deriving more detailed and reliable climate change scenarios for use in
hydrological models for impact assessment. The first part of this study
investigates the current climatic trends in the region. Future climate
change scenarios are obtained from the UK Hadley climate model
(HadCM3) and downscaled to the local climate of the study area. The
downscaled results were used as inputs to the WetSpa hydrological
model, a physically based distributed rainfall-runoff model, which was
used to simulate the resulting hydrological changes. One of the key
findings was that climate change is actually taking place in the study
area. The results further showed that precipitation in the study area will
generally decrease while temperatures will increase with 1-4°C in the dry
periods. These changes will have significant impact on the river
discharge by reducing the flows in the dry periods especially between
May and September, while heavy floods were simulated for the wet
months between November and March. In the 2020’s these changes were
shown to be small, but they will increase significantly beginning the
2050’s. These results provide new findings on the effects of climate
change on water resources in Africa. However, since the downscaling
process is associated with much uncertainty, the findings should provide
a basis for further research of especially the downscaling of precipitation
data.status: publishe