Groundwater Modeling to Assess Climate Change Impacts and Sustainability in the Tana Basin, Upper Blue Nile, Ethiopia

Climate change effects on long-term groundwater (GW) resource developments in the Tana Basin, Ethiopia, are a growing concern. Efforts to provide estimates under various climatic uncertainties lacking region. To address this need, we deployed fine-resolution (500 m) GW model using MODFLOW-NWT for Upper Blue Nile The was calibrated based 98 historical instantaneous well-level measurements (RMSE = 16.36 m, 1.6% of range), and 38 years monthly lake level data 0.2 6.7% range). We used simulate climate impacts by considering two representative concentration pathways, (RCPs) 4.5 8.5, from extreme global circulation models (MIROC5 wetter conditions CSIRO-Mk3 drier conditions) available While MIROC5 simulated table (GWT) found be stable, GWT exhibited large fluctuations within +2 m −4 2100 due change. More critical were predicted lake, where total releases baseline scenario foreseen changed +50% (MIROC5) or −22% (CSIRO-Mk3) end 2100.