Grace Based Water Storage Dynamics in Central Rift Valley Basin of Ethiopia, Integrated Approach

With increasing climate variability and rapid population growth, there is a need for improved understanding of water storage dynamics to underpin sustainable water resources management. However, in-situ monitoring datasets to assess spatiotemporal variability of water resources are limited. The Central Rift Valley basin (Ethiopia) is undergoing agricultural intensification with increased lake and groundwater abstractions for irrigation purposes. Gravity Recovery and Climate Experiment (GRACE) datasets have been employed to examine changes in the Total Water Storage Anomaly (TWSA), 2002-2021. Remotely sensed evapotranspiration and precipitation products were used to validate TWSA. Over 2002-2012 TWSA showed little variability, albeit with a strong seasonal cycle related to precipitation. However, since 2013 the trend has been generally positive. This finding appears counterintuitive given the expansion of irrigation but can be explained by the strong impacts of teleconnections on precipitation and underdevelopment of groundwater. Combining GRACE and satellite altimetry has provided useful insights into lake-aquifer interactions.