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.

Similar to numerous water- and data-scarce regions, Egypt confronts a critical challenge in sustaining food production for its rapidly growing population. Consequently, the country’s water and land resources are under considerable stress and require careful management. About half of Egypt’s both annually harvested areas and renewable freshwater are allocated for cultivating rice, maize, wheat, and berseem clover. However, the extent to which crop production might be improved and how this would impact future water and land requirements remains poorly understood. We analyzed potential improvements in the production of these crops and quantified their future water and land requirements under different scenarios. Potential improvements were detected through percentile analysis in three remote sensing-derived performance indicators for each crop in the Nile Delta’s Zankalon region: (i) crop yield, (ii) crop water productivity, and (iii) transpiration fraction (transpiration to actual evapotranspiration, T/AET). We applied detected improvementsto construct plausible scenarios for Egypt’s water and land requirements to sustain domestic crop production until 2050. Our findings indicate limited potential to improve T/AET (< 4%). However, improvements of up to 27% for crop yields and up to 14% for water productivity are possible. To meet the production targets by 2050, national production must increase by 128, 78, 69, and 71% above the 2016–2020’s average for rice, maize, wheat, and berseem, respectively. Depending on the improvement levels in the developed scenarios, a total harvested land area between 5.3 and 6.4 million ha will be required by 2050, with 18% allocated to rice, 28% to maize, 36% to wheat, and 18% to berseem. Associated freshwater requirements will amount to 59–68 billion cubic meters, divided into 23% for rice, 34% for maize, 28% for wheat, and 15% for berseem. Interventions increasing yields and water productivity will benefit more the summer (rice and maize) than the winter crops (wheat and berseem). We discuss likely interventions for meeting these requirements and for sustaining the supply of these crops in Egypt.

Water scarcity, exacerbated by climate change, population growth, and competing sectoral demands, poses a major threat to agricultural sustainability, particularly in irrigated regions such as the Nile Delta in Egypt. Addressing this challenge requires innovative approaches to evaluate irrigation performance despite the limitations in ground data availability. Traditional assessment methods are often costly, labor-intensive, and reliant on field data, limiting their scalability, especially in data-scarce regions. This paper addresses this gap by presenting a comprehensive and scalable framework that employs publicly accessible satellite data to map crop types and subsequently assess irrigation performance without the need for ground truthing. The framework consists of two parts: First, crop mapping, which was conducted seasonally between 2015 and 2020 for the four primary crops in the Nile Delta (rice, maize, wheat, and clover). The WaPOR v2 Land Cover Classification layer was used as a substitute for ground truth data to label the Landsat-8 images for training the random forest algorithm. The crop maps generated at 30 m resolution had moderate to high accuracy, with overall accuracy ranging from 0.77 to 0.80 in summer and 0.87–0.95 in winter. The estimated crop areas aligned well with national agricultural statistics. Second, based on the mapped crops, three irrigation performance indicators—adequacy, reliability, and equity—were calculated and compared with their established standards. The results reveal a good level of equity, with values consistently below 10%, and a relatively reliable water supply, as indicated by the reliability indicator (0.02–0.08). Average summer adequacy ranged from 0.4 to 0.63, indicating insufficient supply, whereas winter values (1.3 to 1.7) reflected a surplus. A noticeable improvement gradient was observed for all indicators toward the north of the delta, while areas located in the delta’s new lands consistently displayed unfavorable conditions in all indicators. This approach facilitates the identification of regions where agricultural performance falls short of its potential, thereby offering valuable insights into where and how irrigation systems can be strategically improved to enhance overall performance sustainably.

Producing more food for a growing population requires sustainable crop intensification and diversification, particularly in high-potential areas such as the seasonal floodplain wetlands of sub-Saharan Africa (SSA). With emerging water shortages and concerns for conserving these multi-functional wetlands, a further expansion of the cropland area must be avoided as it would entail increased use of blue water (surface and groundwater) for irrigation and infringe on valuable protected areas. We thus advocate an efficient use of the prevailing green water (plant-available water stored in the soil) on the existing cropland areas in seasonal floodplain wetlands, where small-scale farmers grow a single crop of rainfed lowland rice during the wet season. However, soil moisture at the onset of the rains (pre-rice niche) and residual soil moisture after rice harvest (post-rice niche) may suffice to cultivate short-cycled crops. We developed a methodological approach to analyze the potential for green water cultivation in the pre- and post-rice niches in the Kilombero Floodplain in Tanzania, as a representative case for seasonal floodplain wetlands in SSA. The three-step approach used open-access remote sensing datasets to: (i) extract cropland areas following a cross-comparison of multiple land cover products; (ii) analyze soil moisture conditions using evaporative stress indices to identify the pre- and post-rice niches (using MOD16A2GF potential (PET) and actual (AET) evapotranspiration products), and (iii) quantify the green water availability in the identified niches (using an ensemble mean of SSEBop and WaPOR to calculate AET).Results showed that the WaPOR land cover product reliably identified cropland areas in Kilombero, followed by CGLS-LC, while ESA-CCI largely miss-captured the cropland extent and MCD12Q1 did not capture almost any cropland areas. Estimates of the AET ensemble mean product of 2.6 mm/day were comparable with previously reported values in Kilombero cropland (2.05–2.74 mm/day) and were correlated with NDVI (MOD13Q1) on the monthly basis (R2 = 0.58; p 30%) than the post-rice niche (~65 days with AET of 10–30 mm/10-day, inter-annual variability <15%). These findings confirm the large potential for cultivating short-cycled crops beyond the rice-growing period on at least 53% of the total cropland area. A wider application of the developed approach in this study can help identifying opportunities and guiding interventions towards establishing cropping intensification and diversification practices in floodplain wetlands in SSA. The uncertainties, limitations, and implications of the proposed approach are discussed.

Water-Energy-Food Nexus assessments at river basin scale make sense in particular if hydropower is an important source of energy in a given region. The Blue Nile Basin is a major source for Water in the Nile river basin. It provides around 65 % of the flow of the Nile entering Egypt, and occupies a mere 10% of the total basin area. The Blue Nile water is primarily used for irrigation, hydropower, and domestic supply in Ethiopia, Sudan, and Egypt. Climate variability and long-term climate and socio-economic changes pose a growing challenge to the provision of water, energy, and food security within the Blue Nile Basin as well as downstream. Thus, the scientifically sound quantification of available natural resources sustaining water, energy, and food security, and the development of different future scenarios can be helpful for decision-makers in the region. We suggest a new method of WEF Nexus accounting based on quantification of Nexus indicators derived mainly from public domain data. As observed data on water and land resources in the Blue Nile Basin are scarce, this study uses diverse remote sensing-based data sources to derive essential environmental information validated by using ground data, where possible. This includes land cover data, different precipitation products, actual evapotranspiration, net primary productivity (NPP), among others. Furthermore, several data analysis and modeling tools, such as WA+, various hydrological models, RiverWare, CropWat, etc., are employed to quantify the natural resources availability, variability, and productivity as a basis for a comprehensive WEF accounting based on selected indicators which were developed by a team of experts and scientists. The currently constructed Grand Ethiopian Renaissance Dam (GERD) as well as other planned hydropower and irrigation schemes are also considered for the future scenarios. The result is a comprehensive WEF Nexus accounting estimating water availability and uses with a focus on irrigation as the dominant water user, productivities (based on NPP and derived yield estimates), water use efficiency, energy production from hydropower and estimation of security levels compared to the required current and future demands. Finally, the derived nexus indicators are put into context of selected SDG target indicators.