Assessment of Climate and Land Use Change Projections and their Impacts on Flooding

The increase in extreme flooding in urban areas has sparked research interest in the quantitative impact of climate and land use change on flooding in cities. This article presents the results of a study that evaluated climate change and urbanization effects on flood hydrographs. General circulation models (GCMs) were applied to determine global climate change in the coming 100 years depending on various developmental trends and global greenhouse gas emission scenarios. A statistical downscaling methodology was applied on GCMs to generate local future climate data at high resolution. The Future projections of land use change data were combined together with the climate change predictions data and inserted into a hydrological model in order to estimate peak flood discharge rates at Kigali city in Rwanda for considered scenarios. The outcomes of the study show that the downscaled mean annual rainfall indicates neither systematic increments nor decrements in the next 100 years. The hydrological modeling results show the considerable impact of climate change by decreasing the expected flood peaks, whereas the land use change will cause a significant increase in floods. The land use change impacts predominate the climate change impacts at overall evaluation of floods.