Africa is expected to experience water stress before 2025, which is mainly due to increased water demand accompanying an in- crease in populations. Climate change is expected to exacerbate this condition (Bates et al., 2008). Climate change in the past several decades caused precipitation variability, a shift in pattern and frequent extreme events (droughts and floods), and a rise in near surface atmospheric temperature.
It is found that the groundwater flows from uplands toward the Tana Lake. The total inflow to and outflow from the system in the calibrated model are 1733480 m3/d and 1840451 m3/d, respectively. Groundwater level drop, reduction in base flows to surface waters, and in evapotranspiration flux compared to the calibrated values encountered for all scenarios, which are significant (mean 38.4 m, 28.5–100 %, and 97.8 %, respectively) for the worst-case scenario. On the other hand, an increase in groundwater level (mean 9.8 m), base flows (0–14.4 %), and evapotranspiration flux (29.5 %) observed for the optimal scenario when compared to the worst-case scenario results. Results suggest that groundwater management measures should be implemented to mitigate the impacts.
Bahilu_7., 2021