Abstract
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.