ABSTRACT

Climate change is a global phenomenon that become a concern. Climate change affects the hydrological conditions of a watershed, including rainfall. Saguling Reservoir has a high erosion rate on the watershed. One factor that affects erosion based on USLE is the rain erosivity index which has a relation with rainfall amount. So the climate change effect of rainfall on erosivity factor in Saguling Reservoir watershed needs to be investigated because it will affect the erosion rate which is useful to determine the sedimentation rate of the reservoir. The purpose of this study was to analyze the effect of climate change on the erosivity index. Climate change (rainfall) was analyzed using GCM CanESM2 Model in the RCP scenario through a downscaling process. Downscaling has been done with SDSM. The rain erosivity index was analyzed using Lenvain’s formula. Downscaling with the SDSM method was able to give good results based on the coefficient of determination and it was found that there was a change of monthly rainfall in the short, medium, and long term periods, as well as an increase in annual rainfall up to 34.3%. The annual rainfall erosivity index changes along with changes in rainfall due to climate change and there is an increase of up to 44.1%.