Monitoring of crop water consumption, also known as actual evapotranspiration (ETa), is crucial for the prudent use of limited freshwater resources. Remote-sensing-based algorithms have become a popular approach for providing spatio-temporal information on ETa. Satellite-based ETa products are widely available. However, identifying an adequate product remains a challenge due to validation data scarcity. This study developed an assessment process to identify superior ETa products in agricultural areas in Egypt. The land cover product (MCD12Q1) from Moderate Resolution Imaging Spectroradiometer (MODIS) was evaluated and used to detect agricultural areas. The performances of three ETa products, namely: Earth Engine Evapotranspiration Flux (EEFlux), USGS-FEWS NET SSEBop ETa monthly product, and MODIS ETa monthly product (MOD16A2), were evaluated. The ETa values of these products were compared to previous ETa observations and evaluated using the integrated Normalized Difference Vegetation Index (iNDVI) on a seasonal and annual basis. Finally, the irrigation efficiency throughout Egypt was calculated based on the annual Relative Water Supply (RWS) index. Results reveal that the SSEBop monthly product has the best performance in Egypt, followed by the MOD16A2. The EEFlux overestimated ETa values by 36%. RWS had a range of 0.96–1.47, indicating high irrigation efficiency. The findings reported herein can assist in improving irrigation water management in Egypt and the Nile Basin.

The whole Mediterranean is suffering today because of climate changes, with projections of more severe impacts predicted for the coming decades. Egypt, on the southeastern flank of the Mediterranean Sea, is facing many challenges for water and food security, further exacerbated by the arid climate conditions. The Nile River represents the largest freshwater resource for the country, with a minor contribution coming from rainfall and from non-renewable groundwater aquifers. In more recent years, another important source is represented by non-conventional sources, such as treated wastewater reuse and desalination; these water resources are increasingly becoming valuable additional contributors to water availability. Moreover, although rainfall is scarce in Egypt, studies have shown that rainfall and flash floods can become an additional available source of water in the future. While presently rare, heavy rainfalls and flash floods are responsible for huge losses of lives and infrastructure especially in parts of the country, such as in the Sinai Peninsula. Despite the harsh climate, water from these events, when opportunely conveyed and treated, can represent a precious source of freshwater for small communities of Bedouins. In this work, rainfall climatology and flash flood events are presented, together with a discussion about the dynamics of some selected episodes and indications about future climate scenarios. Results can be used to evaluate the water harvesting potential in a region where water is scarce, also providing indications for improving the weather forecast. Basic information needed for identifying possible risks for population and infrastructures, when fed into hydrological models, could help to evaluate the flash flood water volumes at the outlets of the effective watershed(s). This valuable information will help policymakers and local governments to define strategies and measures for water harvesting and/or protection works.