The Nile River is a unique environmental system and essential water resource for its basin riparian nations. Population growth, changes in precipitation patterns, damming and usage rights disputes present extreme challenges in utilizing and managing the basin’s primary water resource. These stress factors are of particular concern for highly populated Egypt, the furthest downstream recipient of the Nile’s water flow. Previously, colonial agreements had granted Egypt and Sudan the majority of water use rights on the Nile without neighboring Ethiopia receiving any specific allocation. Today, Ethiopia plans to increase its energy production through its Nile-powered Grand Ethiopian Renaissance Dam (GERD). While the 74-billion cubic meter (BCM) dam presents promising development opportunities for Ethiopia, the Nile’s altered flow will increase the existing water deficit for Egypt—the quantification and mitigation of which are still largely unconstrained and under intense debate. To address this deficiency, we estimate that the median total annual water budget deficit for Egypt during the filling period, considering seepage into the fractured rocks below and around the GERD reservoir, as well as the intrinsic water deficit and assuming no possible mitigation efforts by Egyptian authorities, will be ∼31 BCM yr−1, which would surpass one third of Egypt’s current total water budget. Additionally, we provide a feasibility index for the different proposed solutions to mitigate the above deficit and assess their economic impact on the GDP per capita. Our results suggest that the unmet annual deficit during the filling period can be partially addressed by adjusting the Aswan High Dam (AHD) operation, expanding groundwater extraction and by adopting new policies for cultivation of crops. If no prompt mitigation is performed, the short-term three-year filling scenario would generate a deficit that is equivalent to losses to the present cultivated area by up to 72% resulting in a total loss of the agricultural GDP by $51 billion during the above-mentioned filling period. Such figures are equivalent to a decrease in the total national GDP per capita by ∼8%, augmenting existing unemployment rates by 11%, potentially leading to severe socioeconomic instability.

The reply herein shows the factual incorrectness of the comment by Eladawy, Asefa and El Nour, which is primarily supported by miscitations and misinterpretations of published research, as well as by claims from social media and unreliable TV interviews. The comment mistakenly ommit the different components of the calculated total water budget deficit in our paper and accordingly claims that it is primarily aimed to create a ‘water panic’, a term that derives from a non-quantitative and subjective reading of the abstract. We show in detail that the comment misrepresents the aim, approach, results, and interpretations reported in our original paper and does not provide any verification on the reproducibility of our results, nor offers any alternative interpretations or suggested impacts on our conclusions which remain valid and unchallenged by the above comment.

We thank Wheeler et al for positively confirming our results’ reproducibility; however, we show herein that their critique misrepresents the aim, approach, and interpretations reported in Heggy et al (2021 Environ. Res. Lett. 16 074022), which remain valid. The reply herein demonstrates that Wheeler et al incorrectly interpreted Heggy et al’s (2021 Environ. Res. Lett. 16 074022) estimates of the median unmitigated total water budget deficit for Egypt of 31 BCM yr−1 to be entirely caused by GERD. The comment overlooks the fact that this estimated value is the sum of Egypt’s existing intrinsic deficit (18.5 BCM yr−1), the initial reservoir seepage (2.5 BCM yr−1), and the median dam impoundment (9.5 BCM yr−1) under different GERD filling scenarios ranging from 2.5 to 29.6 years as shown in figure 2 and section 3.1 in Heggy et al (2021 Environ. Res. Lett. 16 074022). Consequently, our evaluation of the deficit was mistakenly deemed exaggerated as well as the socioeconomic impacts that rely on its estimate. These misinterpretations led to inappropriate comparisons between the results of the unmitigated total water budget deficit under the shortest filling scenario in Heggy et al (2021 Environ. Res. Lett. 16 074022) with longer ones from other studies that focus exclusively on GERD impoundment and assess the economic impacts of water shortage after applying several suggested mitigations that are not yet formally agreed upon, implemented, or budgeted. Instead, Heggy et al (2021 Environ. Res. Lett. 16 074022) provided a holistic evaluation of the current status of the total water budget deficit in Egypt (including intrinsic and GERD components) and its equivalent economic representation to support decision-makers in better implementing the fourth statement of the declaration of principles between the Nile’s riparian countries. The suggestion that the results of the unmitigated scenarios in Heggy et al (2021 Environ. Res. Lett. 16 074022) should match those of the mitigated ones cited in Wheeler et al is erroneous from both hydrological and policy perspectives.