Trends of Hydrometeorological Indices in Tendaho Catchment Part of Awash River Basin, Ethiopia

The variability in the intensity and frequency of extreme hydrometeorological events due to climate change have an enormous impact in managing water resources in developing countries. Frequently it has been recognized sudden droughts and a severe floods. This study analyzed the spatial and temporal trends of five meteorology indices: annual maximum precipitation (AMP),annual precipitation (AP), mean areal precipitation (MAP),annual maximum temperature (AMaT) and annual minimum temperature (AMiT) and three stream flow indices: mean annual flow(MAF), annual maximum flow (AMaxF) and total mean annual flow (TMAF) over the Tendaho Catchment. Mann-Kendall (MK), Spearman Rho (SR), Sen’s slope test in R-program modifiedmk package and Sen innovative trend test were used to detect trends of 16 meteorological and one stream flow stations from 1979-2017. The result showed that there is a statistically significant temporal trends only in AMP, AP, AMaT and AMiT at 6, 19, 56 and 50% of the stations respectively. The remaining indices have no statistically significant trend in all the stations. It also dictates that the catchment is characterized by a slightly increasing AP and AMP; a slightly decreasing MAP and a significant increasing AMaT and AMiT trends. Except AMaT, there is no particular spatial pattern of AP, MAP and AMiT on the majority of the stations. Whereas, all stream flow indices showed a slightly decreasing temporal trend at 95% confidence. From this, we can conclude that the decreasing flow trend could be due to the decrement of MAP, an increment of temperature and construction of reservoirs in the catchment.