Temporal and spatial distribution, variability, and trend of hydroclimate in the Dabus River Basin Upper Blue Nile, Ethiopia

Abstract

<title>Abstract</title> Background High-resolution local scale climate research approach is very effective in examining the existing climate change and predicting its risk. Thus, this study investigated the hydroclimate distribution, variation, trend, and abrupt change points, and considered more than the climate normal time range (1981 to 2020) to determine the climate change of the Dabus River Basin. The study employed different statistical, parametric, and nonparametric modified trend tests, and exact changing point detecting models. Results The result found the basin received 57.7% of the annual rainfall in June, July, and August. The standard anomaly index (SAI) value indicates 1999 and 2000 were the wettest years whereas 1982,1983,1984,1986 and 2015 were the driest years in the area. The basin experienced very fluctuating rainfall for the last four decades. Peaks of Precipitation Concentration Index (PCI) were observed in the years 1987,1991, 2002,2003,2006, and 2011 which indicates the strong irregular distribution of rainfall. The annual mean rainfall and maximum temperature (Tmax) increased significantly (p &lt; 0.05), whereas the annual mean minimum temperature (Tmin), river flow, and river runoff decreased. In Dabus the abrupt increasing change point of annual rainfall was observed in 1996 whereas Tmax in 1993 and 1997. The abrupt decreasing change point of Tmin, river flow, and river runoff was observed in 1987, 1998, and 1999, respectively. Conclusions The study found the climate change in the basin due to the significant increase in temperature with fluctuating rainfall distribution as well as reduction of river flow and runoff. This climate change could upset agriculture, electric power production, and water demand in the basin.