Assessing climate change impacts on streamflow characteristics, water availability, and aquatic ecosystem support in the Omo-Gibe River Basin, Ethiopia, using satellite-based hydrologic simulations

ABSTRACT

Streamflow characteristics and water availability play a fundamental role in sustaining healthy river ecosystems. The quantity, timing, and variability of flow directly influence aquatic habitats, species diversity, and ecosystem processes. Understanding how streamflow patterns support or threaten aquatic life is essential for effective water resource management and conservation. This study investigates the impact of climate change on water resources in the Omo-Gibe River Basin, highlighting its importance for sustainable basin management and planning. The presence of missing values and the scarcity of observed data necessitated the use of reanalysis datasets as a substitute for this study. To enhance hydrologic simulation, satellite-based rainfall estimation datasets TRMM multi-satellite precipitation analysis (TMPA) and NOAA's Climate Prediction Center morphing technique were employed. TMPA gave the highest annual values of 1,466 mm/year, and the high and low flows are better detected by the TMPA datasets. Streamflow was simulated for three future periods and compared with baseline data to assess changes in key flow indicators, including low, medium, and high flows; flow duration curves (FDCs); temporal shifts in peak flows; and seasonal changes in center-of-volume date (CVD) and inverse center-of-volume date (ICVD). The FDCs indicated an increased probability of high-flow events and a likely rise in medium flows across the projected periods under both climate scenarios. The simulated projected peak flow for the EDCDFm method bias-corrected dataset is to occur in the 2060s for the ICHEC RCP4.5 scenario on the year 2043 October month with a value of 5,485 m3/s. Additionally, a significant seasonal shift was observed, with the ICVD moving from March to December, suggesting notable changes in the hydrological timing and potential ecological implications for the basin.