The world faces a huge challenge in balancing water demand for the growing populations andrneconomic development, while protecting the environment with declining freshwater supply.rnDeficit irrigation (DI) and organic mulching (OM), understanding the water footprint (WF) andrnvirtual water will play a key role in sustainable water management in water scarce regions. Thernmain objective of the study is to provide policy relevant information by assessing the virtualrnwater flows and water footprint of major crops produced in the Nile Basin. The research consistsrnof four main components: first, a case study aimed to determining the depth of irrigation and itsrneffect on the yield and water productivity of barley; second an assessment of the blue watersaving potential through DI and OM; third, a spatial analysis of the WF of major crops in thernNile Basin; and, finally, an assessment of the annual variability and long-term changes in WF andrnvirtual water flow of selected major crops in the Nile Basin countries. To determine irrigationrndepth of barely, the irrigation field experiment was arranged in randomized complete blockrndesign (RCBD) with four replicates and five irrigation treatments (fully irrigated treatment (FIT),rn90% FIT, 85% FIT, 80% FIT, & 75% FIT). The AquaCrop model & the global WF accountingrnstandard were used to calculate the WF of crops. For barley production at 80% FIT, the largestrnyield was recorded at 1700 kg/ha. The provision of a certain level of water stress (80% FIT)rnthroughout the growing season, translates to a better yield relative to full irrigation. The FITrn(2.01 kg/m3rn) and 80% FIT (2.95 kg/m3rn) treatments had the lowest and highest waterrnproductivity, respectively. The finding indicates that barley production using DI offers greatrnpotential in improving water use. The blue water-saving potential of DI and OM, the spatial andrntemporal variability of WF, was modeled using the AquaCrop-OS plugin model at a spatialrnresolution of 5x5 arc-minute grid cells for the year 1986-2015 on the basis of a global datarnsource. The blue WF of the selected crops was highest in Egypt, Sudan, South Sudan, andrnTanzania. For the current situation, the total blue WF was 48.5 km3rn/y, 89% of which falls inrnSudan (55%) and Egypt (34%). Production of sorghum account for the largest share of the bluernWF (50%) followed by maize (21%), and rice (16%). DI combined with OM showed to reducernthe current blue WF by as much as 42%. Egypt and Sudan exclusively rely on irrigation waterrnwhile the rest are based on rainfed in which other countries need to use irrigation for betterrnproduction. Rainfall and evapotranspiration are highly variable in all production regions, whichrnare the main drivers affecting the availability and distribution of water resources. Likewise, thernfindings show that there is a substantial difference in green and blue WF among crops across thernBasin countries. The largest average blue WF (mrn3rn/y) in crop production was found in Sudan,rnSouth Sudan, and Egypt. In Sudan, the crops with large WF are maize (6046 mrn3rn/tonne), ricern(5175 mrn3rn/tonne), sorghum (2644 mrn3rn/tonne), and millet (2160 mrn3rn/tonne) and in Egypt, groundnutrn(3138 mrn3rn/tonne). Egypt is the largest exporter of rice with an average net virtual water export ofrn810 Mm3rnper year followed by 19 Mm3rnin Sudan and 16 Mm3rnin Egypt for groundnutsrnproduction. The results of this study have some relevant policy implications and may be of greatrnuse in policy formulation. This research provided empirical evidence of the potential blue water rnPage VIIIrnsaving; WF of crops and virtual water trade across the Nile Basin countries. Water-scarcerncountries like Egypt and Sudan can increase imports of water-intensive crops from relativelyrnwater abundant countries (upstream countries), and vice versa. It is important to know thernnational virtual water trade with internal and external virtual water flows in order to establish arnsound national water policy. Virtual water trading can therefore help to sustain the water use ofrnthe regions in a sustainable manner. It is therefore necessary to use evidence that satisfies thernvarious criteria for the design, planning and implementation of sustainable water resourcernmanagement.