Watershed hydrological response in developing climate change resilience and adaptation strategies, case of Gilgal Gibe watershed, Ethiopia.

Climate change is one of the most challenging and inevitable global environmental problems affecting mankind and its environment regardless of urban and rural areas. Its effect on watershed hydrology is challenging the sustainable water resources management and its availability across the globe. In order to develop a sustainable climate change adaptation strategy, understanding watershed hydrological response to the ever increasing climate change is highly important. Hence, the main objective of this study was investigating role of watershed hydrological response in developing climate resilience and adaptation strategy as a case study in Gilgal Gibe watershed,OmoGibe river basin, Ethiopia. To achieve the main objective of the study, three regional climate models (RCM) derived from one global climate model (GCM) under two greenhouse gas emission scenarios (RCP4.5 and RCP8.5) were collected from CORDEX Africa. The observed weather data and stream flow data were collected from National Meteorological Agency (NMA) and Ministry of Water and Energy (MoWE). The Climate data from CORDEX like maximum and minimum temperature, and precipitation were extracted using R-programming. These data were analyzed against the 1986-2016 baseline data and projected for near-future term (2020-2050) andmid-futureterm (2051-2080). The climate dataset trend analysis over the specified period was conducted using Mann-Kendall test, and the hydrological modeling was performed using the calibrated and validated HEC-HMS hydrological modeling tool. From the analysis, it was found that hydro-climate variability over the proposed time horizon was clearly observed from all RCM under both greenhouse gas emission scenarios. The stream flow revealed an oscillating trend over the course of the operation years under RCP4.5 and RCP8.5 greenhouse gas emission scenarios. Hence, this information is important for water resources manager, decision makers, practitioners and policy makers so as to enable them develop sustainable climate change resilience and adaptation strategies across the watershed.