Water, energy and food resources are fundamental for human survival and are critical for supporting economic development. However, ensuring adequate supply is a major concern for the entire world, specifically in some countries and regions. Under the pressure of population growth, economic development, international trade, urbanization, diversifying diets, cultural and technological changes, global projections indicate a significant further increase in demand for water, energy and food over the next decades. Moreover, the development of these water, energy and food resources are intertwined. As a result, when demand grows, but resources are no longer abundant, competition between sectors increases. Especially in regions with upstream-downstream water connectivity, a national sectoral approach may result in friction, a decrease in mutual trust and international conflicts. On the other hand, the synergistic effects associated with regional resource coordination can contribute to improved resource availability and downstream livelihoods.

To overcome the shortcomings of the current generation of hydro-economic and WEF-nexus models in describing resource cooperation at regional level, in this study a new WEF-framework has been developed in which the heterogeneity in agro-climatic, socio-economic and resource availability, as well as the description of water and electric conveyance infrastructure is included spatially and temporally explicitly. The aim of this research is to create an integrated WEF-framework and to investigate the possibilities for, the relevance of and the challenges and difficulties associated with the implementation of such an integrated model.

The proposed framework includes the river conveyance infrastructure in a multi state river basin by means of a dynamic network model. In addition, a novel approach is used to describe both irrigated and rainfed agriculture in great detail on a regional scale, enabling a good representation of crops with multiple growing cycles per season, a distinction between annual and perennial crop management and the inclusion of agricultural losses. The framework is implemented as a model predictive control (MPC) problem. In this control problem, the reservoir operations and agricultural planning resulting in maximum economic value creation with the available resources are determined with the help of a non-linear problem solver. Receding horizon control accomplishes as part of the MPC framework feedback against uncertain disturbances (e.g. deviations in climate forcing) by applying only the optimal outputs in the first instance of the horizon in simulation and then updating the system states using new information. In addition, this control technique enables information exchange between riparian states within each MPC iteration. This allows us to add two new cooperation scenarios between the often studied scenarios of unilateralism and full coordination, with which the value of information exchange of river flows and trade flows can be studied.

Once developed, the framework is applied in the Eastern Nile basin. The Eastern Nile Basin is home to a large and rapidly growing population. Along with future population growth, changes in socio-economic conditions are expected, which will improve the coverage of the electricity grid and alter diets and water consumption. To meet the growing demand for food and energy, the Nile riparian countries have developed, and intend to further develop, their water resources. However, currently this development takes place unilaterally and can thereby threaten the livelihood in the downstream countries that are highly dependent on these water resources. The application of the proposed model framework aims to describe the qualitative and quantitative benefits and impacts of further collaboration in resource management within a predefined structural environment.

Simulation experiments with a monthly time step are conducted over a historical period between 1990-2010 and a future period between 2020-2040, by screening and incorporation of data on structural, socio-economic and climate constraints and demands. In addition to the four named cooperation scenarios, experiments are compiled to determine trade-offs between hydropower and agricultural water demand, the robustness of the solutions to imperfect climate foresights and the economic trade-offs related to different levels of agricultural self-sufficiency.

Comparative research with trade data from the FAO database indicates that historically every riparian state in the Eastern Nile basin could have benefited from the proposed integrated resource management, even in the unilateral national cases. Despite the variability in extent, all proposed and included forms of cooperation would have been beneficial for all individual states. Regionally, the flow-information, trade-information and regional coordination scenarios could have provided additional benefits of $32, $37 and $50 billion respectively throughout the period. Sharing information about the expected border flows would have generated, relatively in Sudan and absolutely in Egypt, by far the largest additional benefits. However, these benefits appear to correlate strongly with perfect climate foresight information. Because of its upstream location, Ethiopia could not have benefited economically from this flow information sharing. Overall, the benefits of resource optimization would have been relatively small in Ethiopia due to the limited infrastructure present during this period. In addition to the quantitative benefits mentioned, regional coordination also would have enabled the states to increase their resilience against long-lasting droughts and price fluctuations in the external market.

Results of the future model experiments suggest that every state will be disadvantaged in a regional coordinative scenario. To correct these physically and mathematically incorrect results, the current soft constrained implementation of the non-smooth complementarity relations for the reservoir filling process will have to be reconsidered. These non-smooth functions are the first out of three major difficulties encountered when implementing the proposed framework. Other difficulties arise when describing processes on different time scales (e.g. annual crop seasons) and when keeping the problem robust (in case predictions deviate from real events).

Overall, the case study illustrates that the proposed framework can account for spatial and temporal multisectoral trade-offs while finding non-trivial solutions for varying forms of national and regional cooperative resource management. Moreover, the operational resource reallocation choices proposed by this new framework and the spatial diversity in productivity that were discovered indicate that inadequate inclusion of these heterogeneities in WEF-nexus studies results in incomplete and potentially incorrect conclusions

All ecosystem services of river are governed by flow regime. The different components of flow regime like topography, geology, and climatic variation contribute to different ecological processes. These ecosystems provide a wide range of direct and indirect benefits to a human being. The ecosystem services such as hydropower, irrigation, drinking water supply, fisheries, breeding ground for aquatic wild life, sanctuary reserves form the lifeline of many stakeholders. All the water management decisions are based on certain hydrological informations. However, the hydrological information these decisions are based on are not precise and is a simplified version of the actual system. Anthropogenic effects of human intervention on natural flow regime significantly disturbs the natural characteristics of the hydrological flow. Hydrological alterations of river flow regime while benefitting human development in many ways have damaged the delivery of ecosystem services. Growth in human population, decline in resources, ever changing climatic conditions, led to an increase in demand of the resources.The situation is further complicated by multitude of water users and stakeholders with conflicting interests this requires the accurate assessment of the river flow regime taking into account the anthropogenic effects of human intervention in the riverine ecosystem. Reservoir construction is one of the major human intervention to the riverine ecosystem. Construction of reservoirs are usually associated with substantial impacts on river hydrology and surrounding ecosystem. As a result, dams have been constructed to meet the needs of irrigation and energy. These constructions affect the connectivity of the river and eventually changes the entire ecosystem. Topography based hydrological models simulates the response of the catchment due to the different hydrological response units(HRUs). These HRUs are natural and doesn’t take into account anthropogenic factors into account. Therefore, the present study aims to understand the effects of the integration of reservoirs into a Flex-Topo model to assess the model performance.

Scarcity of water resources in Central Asia’s Amu Darya and Syr Darya river basins lies at the root of long-running tensions between Central Asian countries over the division of these resources. Water diplomacy by outside actors aimed at mediating this dispute has so far shown limited results. This thesis investigates what lessons for third-party water diplomacy can be drawn from the water narratives of the Central Asian governments. This question is pursued through a discourse analysis of government publications. This analysis reveals that four distinct discourses can be identified in the Tajik and Uzbek government narratives, which can be classified along two axes: upstream-downstream and international-domestic. The first distinction is to be expected, but the second warrants a closer look. A comparison with publications by governments engaged in regional water diplomacy shows that the Central Asian government discourses aimed at international audiences skew much more closely to the stated priorities of mediators and donors than their discourses for domestic consumption do. This implies that water diplomats should be careful in taking the narrative of Central Asian governments at face value and should pay close attention to their domestic narrative in order to carry out successful mediation.

Water scarcity has been a growing problem for many places around the world as water usage has been increasing with double the rate of population growth in the twentieth century. As agriculture accounts for 70 percent of global freshwater withdrawals, fresh water availability will thus face even greater stress (World Bank, 2013). Sustainable Development Goals (SDG’s) 2, 6 and 7 (UN, 2015) show that the achievement of water, food, and energy security have been set to a high priority on the global world agenda. However, achieving these goals cannot be done without a proper understanding of the interlinkages between the sectors. As water resources become more stretched, the energy and food sectors’ dependence on water implies that decision-makers in all three domains should increasingly focus on water resource management as part of their policy and practice (“Water, Food and Energy | UN-Water,” n.d.).

In light of this, the Food and Agricultural Organization (FAO) of the United Nations launched the so-called Water Productivity Open-access portal (WaPOR). The portal provides free and open access to processed satellite data that enables monitoring of land and water productivity throughout Africa and the Middle East in near real time. Crop Water Productivity is defined as the crop yield per unit of water consumed, expressed in kg/m3. The objective of this thesis is to explore and assess the available datasets provided by WaPOR to improve current water resource management practices in agriculture in the Eastern Nile Basin countries. The study focuses on the quantification of monthly water withdrawals for irrigation purposes, as well as benchmarking physical water productivity of the main irrigated crops within so-called Agro-Ecological Zones of each country. Throughout this study, crop water productivity is assessed and defined as the amount of agricultural yield that can be attained per unit of water that was allocated for its production, expressed in kg/m3. Data analysis and modeling are the major tools applied to assess spatial variation of water withdrawals and water productivity and subsequently to explain the results. The results are both the quantification of monthly water withdrawals for irrigation purposes, as well as benchmarking crop water productivity of the main irrigated crops within of the countries of the case study: Egypt, Sudan and Ethiopia.

Irrigation is considered the largest water-consuming sector in the world and has great potential to become more water-efficient. Rain-fed agriculture, however, does not influence the water balance within a catchment and can thus not improve its water efficiency. Separating irrigated agriculture from rain-fed agriculture can be done by splitting the total evaporation in so-called green and blue water evaporation. Evaporation from green water is the part of the actual evaporation that is derived from rainfall that infiltrated into the soil, while evaporation from blue water is due to the use of human-made infrastructure such as pumps, with the purpose of irrigation. With blue water evaporation, the total water consumption [m3] that was used for irrigation can subsequently be calculated. This can be used to then calculate the water productivity, but also provides insight into the current water management practices of a country. The principle of the Budyko Curve has been applied to obtain blue water evaporation (Budyko, 1974), in compliance with the Water Accounting Plus procedure that was developed at IHE Delft by Wim Bastiaanssen et al. (Bastiaanssen, W.G.M., Coerver, 2017). Finally, water consumption was obtained by multiplying the pixel size with the sum of the monthly blue evaporation. The outcome of these calculations provides a water consumption expressed in m3/month.

Water productivity is calculated by dividing agricultural yield [kg] by the amount of water that was consumed for its production [m3]. Agricultural yield was obtained by multiplying above ground biomass production (AGBP) with a crop harvest index according to the crop that was identified with the phenology data. To determine the specific growing season of a pixel, so-called “Start Of Season” (SOS) and “End OF Season” (EOS) phenology data are combined. By comparing the growing season of the pixel with literature from the FAO crop calendar, the crop type could be determined. The total water consumption between the SOS and EOS dekad numbers is summed to provide the total water consumption during the growing season of the crop. This way Crop Water Productivity is eventually obtained.

Throughout this thesis, the assumption was made that crops could be distinguished and recognized, based on the available phenology data. Considering the fact that a ‘no season’ label is applied when no growing season can be distinguished, agricultural cropland was thought to be identified through this method. However, from the fact that reasonable results complying with the literature are found with the use of the FAO LCC Land Cover Map, it follows that the identification of crops through phenology and blue evaporation data does not provide accurate results. This is especially the case for Ethiopia and to a lesser extent Sudan, likely due to the fact that Egypt has hardly any rainfall and therefore consists almost solely of irrigated agriculture. Similarly, ground truthing should therefore be done regarding crop identification and the presence of irrigation per pixel.

Calculating water withdrawals gave a promising outcome for Egypt, as the calculated water withdrawals were almost similar to the water withdrawals stated by AQUASTAT. However, numbers differed by a factor 10 for both Sudan and Ethiopia. When the FAO WaPOR LCC mask is applied, better results are achieved. The calculated water withdrawals for Egypt, Sudan, and Ethiopia are lower than FAO AQUASTAT’s numbers. It should, however, be noted that FAO AQUASTAT’s numbers are based on the required water withdrawals, while WaPOR calculates the effective water withdrawals. Lower values could imply low efficiencies of the irrigation systems, which is not uncommon for all three countries. With a typical irrigation efficiency of 60 to 70% (Howell, 2003), the total amount of water withdrawals can be computed with Q_irrigation/0.65 (Kwast et al., 2016). When this is taken into consideration, the results seem promising.

Overlapping phenologies of crops and the indistinct connection with the above ground biomass data are factors that caused unreliable results for the calculation of crop water productivity. The high CWP values that were found in Ethiopia are high compared to the reasonable values found in Egypt and Sudan. This could possibly be due to the fact that the pixels are wrongly identified as irrigated pixels. After all, CWP was assessed for all pixels that contain blue evaporation and was not masked with the FAO WaPOR LCC mask. It is therefore recommended to use an accurate land use mask when CWP is assessed.