The Observed Hydroclimate Variability and Changes in the Guder River Watershed, Blue Nile Basin

Abstract

Analysis of hydroclimate variability and trends provides crucial information for sustainable water management in a changing environment. The objective of this study was to analyze trends and changes in hydroclimate variables and examine the potential drivers of streamflow variability in the Guder River watershed. Statistical techniques, including the Mann-Kendall trend test, Pettit’s test, Sen’s slope estimator, and correlation analysis, have been used in conjunction with the SWAT hydrological model. The result indicated that the temperature in the watershed showed a significant increasing trend at the majority of stations. The observed precipitation trends were inhomogeneous across different seasons and stations. However, the mean annual precipitation over the watershed and the majority of stations displayed a statistically insignificant upward trend. However, the streamflow at the watershed outlet exhibited an insignificant decreasing trend in the spring and on an annual basis. These discrepancies in the observed minor change between the two variables could be due to the effects of increased warming, changes in land use and land cover (LULC). The observed weak correlation between winter streamflow and precipitation suggests that non-climatic factors majorly influence the streamflow during the dry season. The findings of this study can serve as a baseline for predicting the future hydrological impacts of climate change and for water management planning in this watershed.