Eastern Nile River Basin Research Articles

Comparison of different machine-learning algorithms for land use land cover mapping in a heterogenous landscape over the Eastern Nile river basin, Ethiopia

Land use/land cover (LULC) information is regarded as one of the most important variables in global change studies. Several LULC classification algorithms are available with different levels of accuracy in LULC mapping under different geographical setups. Furthermore, different remote sensing (RS) based indices and auxiliary data have been reported to have contributed to the accuracy of LULC mapping. Hence, the main aim of this study was to compare the different ML algorithms for the LULC mapping and explicitly assess the potential contribution of different RS-derived indices and auxiliary data on classification accuracy in the Upper Tekeze-Atbarah (UTA) river basin in Ethiopia. The overall classifiers evaluation result revealed that random forest (RF) performed best and followed by K-Nearest Neighbour (KNN), Support Vector Machine (SVM), Artificial Neural Network (ANN), Maximum Likelihood Classification (MLC), and Classification and Regression Tree (CART). Compared to RF, the MLC method showed less accuracy by 16.2% (19.7%) in OA (kappa coefficient) respectively, which showed that the currently emerging ML classifiers contributed to an improvement in LULC mapping. The use of RS-derived indices and DEM as predictors together with the Landsat bands improved the overall accuracy and kappa coefficient by 5.5% and 7% respectively. Furthermore, the discrepancy in the classified LULC map from RF and other classifiers was compared at pixel-level and the result showed a considerable disagreement between the LULC maps. For instance, when the LULC map from RF and KNN are compared, only 80.6% of the area has the same LULC condition. This result reflects the potential discrepancy that could exist in LULC maps from different classifiers. The hydrological simulation under each of the classified map also resulted in a considerable difference in the major water balance components. In a conclusion, given the considerable difference in classifier performance and the potential propagation of errors in LULC maps to further applications such as water resources assessment, it is highly recommended to explicitly evaluate the available classifiers. Users should also harness the power of RS indices and auxiliary datasets for improved LULC mapping.

Examining the Accuracy of Using a Single Short-Term Historical Flow Period to Assess the Nile’s Downstream Water Deficit from GERD Filling: A Technical Note

Increasing water and energy demands, hydroclimatic fluctuations, damming, and usage rights disputes present major challenges in managing transboundary rivers worldwide. Of particular interest is the Eastern Nile River Basin (ENRB), which is subject to broad debate over which modeling approach should be applied to resolve the disparities in transboundary water management among the river’s riparian nations, under increased upstream damming. Several studies have simulated the downstream High Aswan Dam (HAD) storage change during the Grand Ethiopian Renaissance Dam (GERD) filling under different hydrological conditions. However, their findings diverge regarding the impacts of GERD filling on HAD storage, especially when considering a specific, naturalized, historical 10-year period to represent the average flow condition used, as a benchmark for assessing potential downstream impacts. Our extended analysis of the Nile flow historical records demonstrates that considering a single historical 10-year period to simulate the downstream water budget, as performed in Wheeler et al. (Nat Commun 11:5222, 2020, https://doi.org/10.1038/s41467-020-19089-x), widely communicated to policymakers as a robust proof that GERD filling will not generate a deficit at HAD under average flow conditions, is inconclusive as it strongly depend on the selection of the historical inflow period, due to the river high interannual flow variability. Our simulation results of 20 average/near average historical flow periods in Wheeler et al. (Nat Commun 11:5222, 2020, https://doi.org/10.1038/s41467-020-19089-x)’s datasheet indicates that 60% of them generates a downstream water deficit ranging from 0.5 to 14.5 BCM under the same modeling conditions and filling policy. Therefore, considering the simulation results of multiple flow sequences is crucial for accurately reflecting the impact of the Nile’s high interannual flow variability on downstream water deficit assessments, thereby settling the disparities in transboundary water management forecasts for the impacts of GERD filling and operation.

The Post-1990s Hydro- Diplomacy in Eastern Nile Basin Towards Changing the Power Asymmetry


 
 
 There have been diplomatic tensions and instances of threatening and concerned rhetoric between the countries of the Nile, especially between Egypt, Sudan and Ethiopia. This paper examined the post 1990 water diplomacy in eastern Nile River basin. For a long period of time in eastern Nile basin Egypt used to contain and influence the behavior of Sudan and other Nile River riparian states, particularly over issues pertaining to the utilization of the Nile’s waters. This paper argues the post 1990 multi-lateral water diplomacy especially NBI reduce the established power asymmetries, while contributing to the "sustainable socio-economic development of all riparian’s through the equitable utilization of, and benefit from, the common Nile basin water resources. On the other hand, following NBI, Ethiopia shifted from ‘silent partner’ to ‘bargaining power’ so that it involved through a successive water deal among the nine countries. Consequently, in 2009, the discussions among the Nile riparian are on establishing a cooperative framework agreement reached and the constructions of Ethiopia Grand Renaissance Dam on the Blue Nile near the Ethiopian– Sudanese border transforming Ethiopia from “silent partner” to “influential partner and it is considered as a historic event not only for Ethiopia but also for the members of NBI’s. Drawing from lesson this article suggested that the Egyptians stand might not be consistence and the discussions and negation of Ethiopia on GERD project increasingly signaled a more flexible position on cooperating with the upstream states.
 
 

Cooperation in a transboundary river basin: a large-scale socio-hydrological model of the Eastern Nile

Abstract. While conflict-and-cooperation phenomena in transboundary basins have been widely studied, much less work has been devoted to representing the process interactions in a quantitative way. This paper identifies the main factors in the riparian countries' willingness to cooperate in the Eastern Nile River basin, involving Ethiopia, Sudan, and Egypt, from 1983 to 2016. We propose a quantitative model of the willingness to cooperate at the national and river basin scales. Our results suggest that relative political stability and foreign direct investment can explain Ethiopia's decreasing willingness to cooperate between 2009 and 2016. Further, we show that the 2008 food crisis may account for Sudan recovering its willingness to cooperate with Ethiopia. Long-term lack of trust among the riparian countries may have reduced basin-wide cooperation. While the proposed model has some limitations regarding model assumptions and parameters, it does provide a quantitative representation of the evolution of cooperation pathways among the riparian countries, which can be used to explore the effects of changes in future dam operation and other management decisions on the emergence of conflict and cooperation in the basin.

A hybrid partial and general equilibrium modeling approach to assess the hydro-economic impacts of large dams – The case of the Grand Ethiopian Renaissance Dam in the Eastern Nile River basin

A novel integrated hydro-economic modeling framework that links a bottom-up partial equilibrium (engineering) model with a top-down (economic) general equilibrium model is developed for assessing the regional economic impacts of water resources management and infrastructure development decisions in a transboundary river basin. The engineering model is employed first to solve the water allocation problem for a river system in a partial equilibrium setting. The resulting system-wide changes in optimal water allocation are subsequently fed into the general equilibrium model to provide an economy-wide perspective. This integrated hydro-economic modeling framework is illustrated using the Eastern Nile River basin as a case study. The engineering-based stochastic dual dynamic programming (SDDP) model of the Eastern Nile basin is coupled with the computable general equilibrium (CGE) model GTAP-W to assess the economy-wide impacts of the Grand Ethiopian Renaissance Dam (GERD) on the Eastern Nile economies.

Sharing water and benefits in transboundary river basins

Abstract. The equitable sharing of benefits in transboundary river basins is necessary to solve disputes among riparian countries and to reach a consensus on basin-wide development and management activities. Benefit-sharing arrangements must be collaboratively developed to be perceived not only as efficient, but also as equitable in order to be considered acceptable to all riparian countries. The current literature mainly describes what is meant by the term benefit sharing in the context of transboundary river basins and discusses this from a conceptual point of view, but falls short of providing practical, institutional arrangements that ensure maximum economic welfare as well as collaboratively developed methods for encouraging the equitable sharing of benefits. In this study, we define an institutional arrangement that distributes welfare in a river basin by maximizing the economic benefits of water use and then sharing these benefits in an equitable manner using a method developed through stakeholder involvement. We describe a methodology in which (i) a hydrological model is used to allocate scarce water resources, in an economically efficient manner, to water users in a transboundary basin, (ii) water users are obliged to pay for water, and (iii) the total of these water charges is equitably redistributed as monetary compensation to users in an amount determined through the application of a sharing method developed by stakeholder input, thus based on a stakeholder vision of fairness, using an axiomatic approach. With the proposed benefit-sharing mechanism, the efficiency–equity trade-off still exists, but the extent of the imbalance is reduced because benefits are maximized and redistributed according to a key that has been collectively agreed upon by the participants. The whole system is overseen by a river basin authority. The methodology is applied to the Eastern Nile River basin as a case study. The described technique not only ensures economic efficiency, but may also lead to more equitable solutions in the sharing of benefits in transboundary river basins because the definition of the sharing rule is not in question, as would be the case if existing methods, such as game theory, were applied, with their inherent definitions of fairness.

Economic evaluation of the proposed alternatives of inter-basin water transfer from the Baro Akobo to Awash basin in Ethiopia

Water resources in Ethiopia are relatively skewed towards basins with rivers flowing to the west and southwest. Baro Akobo, which is a part of the eastern Nile River basin, is a west-flowing river with water availability of about 3432 m3 per person per year. Awash basin in the east is a water-deficit basin with just about 325 m3 per person. This study identifies and analyses the three possible alternatives of water transfer from Baro Akobo to Awash basin in Ethiopia. The first proposed link is about 685 km long, out of which about 516 km flow is under gravity, while 167 km is proposed to be pumped. The total cost of this link is about 1.793 billion USD. The second proposed link involves 542 km-long water conveyance and its approximate cost will be 1.84 billion USD. The third proposed option suggests a water conveyance of 519 km with an approximate cost of 1.637 billion USD. All the three possible alternatives are critically evaluated and then the most feasible and economical option is recommended for the inter-basin water transfer from Baro Akobo to Awash basin in Ethiopia.

Economic and hydrological impacts of the Grand Ethiopian Renaissance Dam on the Eastern Nile River Basin

AbstractWe propose an ‘allocate-and-trade’ institution to manage the eastern Nile River Basin for Ethiopia, Sudan and Egypt as the basin faces a new reality of the Grand Ethiopian Renaissance Dam (GERD). We find that a social planner could increase the region's economic welfare by assigning water rights to the riparian states. An alternative intrabasin water rights arrangement and trade could achieve more than 95 per cent of the welfare created by the social planner. GERD will change both the economic benefits and hydrological positions of the riparian countries. Economic benefits from alternative water use would be sufficient to make riparian countries better off compared with the status quo. Furthermore, riparian countries could raise more than US$680 m annually for protecting and conserving the natural resources of the region.

A dynamic water accounting framework based on marginal resource opportunity cost

Abstract. Many river basins throughout the world are increasingly under pressure as water demands keep rising due to population growth, industrialization, urbanization and rising living standards. In the past, the typical answer to meet those demands focused on the supply side and involved the construction of hydraulic infrastructures to capture more water from surface water bodies and from aquifers. As river basins have become more and more developed, downstream water users and ecosystems have become increasingly dependent on the management actions taken by upstream users. The increased interconnectedness between water users, aquatic ecosystems and the built environment is further compounded by climate change and its impact on the water cycle. Those pressures mean that it has become increasingly important to measure and account for changes in water fluxes and their corresponding economic value as they progress throughout the river system. Such basin water accounting should provide policy makers with important information regarding the relative contribution of each water user, infrastructure and management decision to the overall economic value of the river basin. This paper presents a dynamic water accounting approach whereby the entire river basin is considered as a value chain with multiple services including production and storage. Water users and reservoir operators are considered as economic agents who can exchange water with their hydraulic neighbors at a price corresponding to the marginal value of water. Effective water accounting is made possible by keeping track of all water fluxes and their corresponding hypothetical transactions using the results of a hydro-economic model. The proposed approach is illustrated with the Eastern Nile River basin in Africa.

Hydro-economic risk assessment in the eastern Nile River basin

Abstract In 2011, the Ethiopian government announced plans for the construction of the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile, east of its border with Sudan, at a cost of almost 5 billion USD. The project is expected to generate over 5 TWh of electricity per year and will include a reservoir of more than 60 km3 capacity. This project is part of a larger development scheme, by the Ethiopian government to expand its hydropower capacity; however, the scheme faces strong concerns, mainly from Egypt who are highly dependent on Nile River flows originating in Ethiopia. The Ethiopian government argues that the dam would supply electricity for Ethiopians and neighbouring countries and would generate positive externalities downstream by reducing floods and providing more constant and predictable flows. This study provides an independent analysis of the hydrologic and economic risks faced by downstream countries when the GERD will be online. To achieve this, an integrated, stochastic hydro-economic model of the entire Eastern Nile River basin is used to analyse various development and management scenarios. Results indicate that if riparian countries agree to cooperative management of the basin, and its major infrastructure, the GERD would significantly increase basin-wide benefits, especially in Ethiopia and in Sudan, and would generate positive externalities in Sudan and Egypt during dry years.

Sensitivity of SWAT simulated streamflow to climatic changes within the Eastern Nile River basin

Abstract. The hydrological model SWAT was run with daily station based precipitation and temperature data for the whole Eastern Nile basin including the three subbasins: the Abbay (Blue Nile), BaroAkobo and Tekeze. The daily and monthly streamflows were calibrated and validated at six outlets with station-based streamflow data in the three different subbasins. The model performed very well in simulating the monthly variability while the validation against daily data revealed a more diverse performance. The simulations indicated that around 60% of the average annual rainfalls of the subbasins were lost through evaporation while the estimated runoff coefficients were 0.24, 0.30 and 0.18 for Abbay, BaroAkobo and Tekeze subbasins, respectively. About half to two-thirds of the runoff could be attributed to surface runoff while the other contributions came from groundwater. Twenty hypothetical climate change scenarios (perturbed temperatures and precipitation) were conducted to test the sensitivity of SWAT simulated annual streamflow. The result revealed that the annual streamflow sensitivity to changes in precipitation and temperature differed among the basins and the dependence of the response on the strength of the changes was not linear. On average the annual streamflow responses to a change in precipitation with no temperature change were 19%, 17%, and 26% per 10% change in precipitation while the average annual streamflow responses to a change in temperature and no precipitation change were −4.4% K−1, −6.4% K−1, and −1.3% K−1 for Abbay, BaroAkobo and Tekeze river basins, respectively. 47 temperature and precipitation scenarios from 19 AOGCMs participating inCMIP3 were used to estimate future changes in streamflow due to climate changes. The climate models disagreed on both the strength and the direction of future precipitation changes. Thus, no clear conclusions could be made about future changes in the Eastern Nile streamflow. However, such types of assessment are important as they emphasise the need to use several an ensemble of AOGCMs as the results strongly dependent on the choice of climate models.

Optimal operation of a multipurpose multireservoir system in the Eastern Nile River Basin

Abstract. The upper Blue Nile River Basin in Ethiopia is a largely untapped resource despite its huge potential for hydropower generation and irrigated agriculture. Controversies exist as to whether the numerous infrastructural development projects that are on the drawing board in Ethiopia will generate positive or negative externalities downstream in Sudan and Egypt. This study attempts at (1) examining the (re-)operation of infrastructures, in particular the proposed reservoirs in Ethiopia and the High Aswan Dam and (2) assessing the economic benefits and costs associated with the storage infrastructures in Ethiopia and their spatial and temporal distribution. To achieve this, a basin-wide integrated hydro-economic model has been developed. The model integrates essential hydrologic, economic and institutional components of the river basin in order to explore both the hydrologic and economic consequences of various policy options and planned infrastructural projects. Unlike most of the deterministic economic-hydrologic models reported in the literature, a stochastic programming formulation has been adopted in order to: (i) understand the effect of the hydrologic uncertainty on management decisions, (ii) determine allocation policies that naturally hedge against the hydrological risk, and (iii) assess the relevant risk indicators. The study reveals that the development of four mega dams in the upper part of the Blue Nile Basin would change the drawdown refill cycle of the High Aswan Dam. Should the operation of the reservoirs be coordinated, they would enable an average annual saving of at least 2.5 billion m3 through reduced evaporation losses from the Lake Nasser. Moreover, the new reservoirs (Karadobi, Beko-Abo, Mandaya and Border) in Ethiopia would have significant positive impacts on hydropower generation and irrigation in Ethiopia and Sudan: at the basin scale, the annual energy generation is boosted by 38.5 TWh amongst which 14.2 TWh due to storage. Moreover, the regulation capacity of the above mentioned reservoirs would enable an increase of the Sudanese irrigated area by 5.5%.