Exploring Cooperative Transboundary River Management Strategies for the Eastern Nile Basin.
TL;DR: The method demonstrates how improvements to water security for both downstream riparians can be achieved through dynamic adaptation of the operation of the Grand Ethiopian Renaissance Dam during drought conditions and the robustness of potential management arrangements can be evaluated considering potential effects of climate change.
Abstract: A water resource modeling process is demonstrated to support multistakeholder negotiations over transboundary management of the Nile River. This process addresses the challenge of identifying management options of new hydraulic infrastructure that potentially affects downstream coriparian nations and how the management of existing infrastructure can be adapted. The method includes an exploration of potential management decisions using a multiobjective evolutionary algorithm, intertwined with an iterative process of formulating cooperative strategies to overcome technical and political barriers faced in a transboundary negotiation. The case study is the addition of the Grand Ethiopian Renaissance Dam (GERD) and considers how its operation may be coordinated with adaptations to the operations of Egypt's High Aswan Dam. The results demonstrate that a lack of coordination is likely to be harmful to downstream riparians and suggest that adaptations to infrastructure in Sudan and Egypt can reduce risks to water supplies and energy generation. Although risks can be substantially reduced by agreed releases from the GERD and basic adaptations to the High Aswan Dam, these measures are still insufficient to assure that no additional risk is assumed by Egypt. The method then demonstrates how improvements to water security for both downstream riparians can be achieved through dynamic adaptation of the operation of the GERD during drought conditions. Finally, the paper demonstrates how the robustness of potential management arrangements can be evaluated considering potential effects of climate change, including increased interannual variability and highly uncertain changes such as increases in the future persistence of droughts.
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TL;DR: This analysis illustrates how during filling the HAD reservoir could fall to levels not seen in recent decades, although the risk of water shortage in Egypt is relatively low, and a new normal period after the reservoir fills; and a severe multi-year drought after the filling.
Abstract: When construction of the Grand Ethiopian Renaissance Dam (GERD) is completed, the Nile will have two of the world’s largest dams—the High Aswan Dam (HAD) and the GERD—in two different countries (Egypt and Ethiopia). There is not yet agreement on how these dams will operate to manage scarce water resources. We elucidate the potential risks and opportunities to Egypt, Sudan and Ethiopia by simulating the filling period of the reservoir; a new normal period after the reservoir fills; and a severe multi-year drought after the filling. Our analysis illustrates how during filling the HAD reservoir could fall to levels not seen in recent decades, although the risk of water shortage in Egypt is relatively low. The new normal will benefit Ethiopia and Sudan without significantly affecting water users in Egypt. Management of multi-year droughts will require careful coordination if risks of harmful impacts are to be minimized. Several dams and reservoirs exist along the Nile, most notably the HAD (Egypt) and GERD (Ethiopia) dams. Due to the lack of strategies, the authors here explore potential risks and solutions how to use both dams simultaneously.
77 citations
TL;DR: In this article, the authors evaluated the effectiveness of reservoir regulation for changing hydrological extremes in the Lancang-Mekong River Basin (LMRB) in the 21st century.
40 citations
TL;DR: Water Diplomacy: A Negotiated Approach to Managing Complex Water Networks, by Shafiqul Islam and Lawrence Susskind, provides a refreshingly compelling alternative to overcoming water conflicts.
Abstract: All nations have built their economies around water that is naturally available. Almost all sectors of the economy depend on water. Yet there is conflict among various users for the finite amount of water that is available. Managers and practitioners have long held the notion that competition rather than collaboration is the solution when there is conflict. Water Diplomacy: A Negotiated Approach to Managing Complex Water Networks, by Shafiqul Islam and Lawrence Susskind, provides a refreshingly compelling alternative to overcoming water conflicts. The book argues that the dynamic sociopolitical and socioeconomic constraints of water resources are best addressed in a “diplomacy” framework. The book rebuts, using several case studies, the technically rigid competition approach of today's water sharing practice.
37 citations
TL;DR: In this paper, the authors investigate governance processes leading to reservoir management strategies ignoring downstream water needs in one of the most important water towers of the world, the European Alps, and assess why governance processes can lead to a coordination gap between an upstream reservoir and downstream water need.
Abstract: Mountains play an essential role in storing water and providing it to downstream regions and are therefore commonly referred to as “water towers of the world” (Immerzeel et al., 2020; Viviroli et al., 2020). In particular, they provide runoff in the lowlands' low flow season by contributing snowand glacier-melt (Jenicek et al., 2018). Globally, 1.9 billion people depend on these runoff contributions from mountains (Immerzeel et al., 2020), which are currently and in future impacted by climate change through the retreat and volume loss of glaciers (Dussaillant et al., 2019; Huss & Hock, 2018; Zekollari et al., 2019), rising snow lines, changes in precipitation amount and seasonality, and changes in evapotranspiration (Arnell, 2003; IPCC, 2014). Abstract Mountains, said to be the world's water towers, are central for the provision of downstream water demands. This provision service is strongly challenged by climate change associated with changes in runoff amount and seasonality caused by the retreat of glaciers, rising snow lines, and changes in precipitation. One potential adaptation strategy is the construction of new water reservoirs or the adjustment of current reservoir management strategies. These strategies need to account for various water uses originating from sectors and governments with different economic interests. Here, we investigate governance processes leading to reservoir management strategies ignoring downstream water needs in one of the most important water towers of the world, the European Alps. We assess why governance processes can lead to a coordination gap between an upstream reservoir and downstream water needs. We show that downstream water deficits could potentially be covered through an upstream reservoir under mean and partially under extremely low inflow conditions. However, these hydrological conditions were neglected in the governance processes. The decision-making when issuing the new reservoir concession was influenced by (a) a lack of knowledge and of an appropriate reservoir-management study, (b) an interest to increase renewable energy production, (c) a focus on environmental agreements in the participatory process, and (d) economic interests. Our analyses provide factors, which need to be considered when designing governance processes for the management of reservoirs in world's important and vulnerable water towers. We conclude that immediate action is required toward balancing upstream and downstream water needs in governance processes.
21 citations
TL;DR: In this paper, the authors apply a bias-correction and spatial disaggregation (BCSD) approach to seasonal precipitation, temperature and radiation forecasts of the latest long-range seasonal forecasting system SEAS5 of the European Centre for Medium-Range Weather Forecasts (ECMWF).
Abstract: . Seasonal forecasts have the potential to substantially improve water management particularly in water-scarce regions. However, global seasonal forecasts are usually not directly applicable as they are provided at coarse spatial resolutions of at best 36 km and suffer from model biases and drifts. In this study, we therefore apply a bias-correction and spatial-disaggregation (BCSD) approach to seasonal precipitation, temperature and radiation forecasts of the latest long-range seasonal forecasting system SEAS5 of the European Centre for Medium-Range Weather Forecasts (ECMWF). As reference we use data from the ERA5-Land offline land surface rerun of the latest ECMWF reanalysis ERA5. Thereby, we correct for model biases and drifts and improve the spatial resolution from 36 km to 0.1 ∘ . This is performed for example over four predominately semi-arid study domains across the world, which include the river basins of the Karun (Iran), the Sao Francisco River (Brazil), the Tekeze–Atbara river and Blue Nile (Sudan, Ethiopia and Eritrea), and the Catamayo–Chira river (Ecuador and Peru). Compared against ERA5-Land, the bias-corrected and spatially disaggregated forecasts have a higher spatial resolution and show reduced biases and better agreement of spatial patterns than the raw forecasts as well as remarkably reduced lead-dependent drift effects. But our analysis also shows that computing monthly averages from daily bias-corrected forecasts particularly during periods with strong temporal climate gradients or heteroscedasticity can lead to remaining biases especially in the lowest- and highest-lead forecasts. Our SEAS5 BCSD forecasts cover the whole (re-)forecast period from 1981 to 2019 and include bias-corrected and spatially disaggregated daily and monthly ensemble forecasts for precipitation, average, minimum, and maximum temperature as well as for shortwave radiation from the issue date to the next 215 d and 6 months, respectively. This sums up to more than 100 000 forecasted days for each of the 25 (until the year 2016) and 51 (from the year 2017) ensemble members and each of the five analyzed variables. The full repository is made freely available to the public via the World Data Centre for Climate at https://doi.org/10.26050/WDCC/SaWaM_D01_SEAS5_BCSD (Domain D01, Karun Basin (Iran), Lorenz et al. , 2020 b ) , https://doi.org/10.26050/WDCC/SaWaM_D02_SEAS5_BCSD (Domain D02: Sao Francisco Basin (Brazil), Lorenz et al. , 2020 c ) , https://doi.org/10.26050/WDCC/SaWaM_D03_SEAS5_BCSD (Domain D03: basins of the Tekeze–Atbara and Blue Nile (Ethiopia, Eritrea, Sudan), Lorenz et al. , 2020 d ) , and https://doi.org/10.26050/WDCC/SaWaM_D04_SEAS5_BCSD (Domain D04: Catamayo–Chira Basin (Ecuador, Peru), Lorenz et al. , 2020 a ) . It is currently the first publicly available daily high-resolution seasonal forecast product that covers multiple regions and variables for such a long period. It hence provides a unique test bed for evaluating the performance of seasonal forecasts over semi-arid regions and as driving data for hydrological, ecosystem or climate impact models. Therefore, our forecasts provide a crucial contribution for the disaster preparedness and, finally, climate proofing of the regional water management in climatically sensitive regions.
18 citations
References
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TL;DR: In this paper, the authors present guidelines for watershed model evaluation based on the review results and project-specific considerations, including single-event simulation, quality and quantity of measured data, model calibration procedure, evaluation time step, and project scope and magnitude.
Abstract: Watershed models are powerful tools for simulating the effect of watershed processes and management on soil and water resources. However, no comprehensive guidance is available to facilitate model evaluation in terms of the accuracy of simulated data compared to measured flow and constituent values. Thus, the objectives of this research were to: (1) determine recommended model evaluation techniques (statistical and graphical), (2) review reported ranges of values and corresponding performance ratings for the recommended statistics, and (3) establish guidelines for model evaluation based on the review results and project-specific considerations; all of these objectives focus on simulation of streamflow and transport of sediment and nutrients. These objectives were achieved with a thorough review of relevant literature on model application and recommended model evaluation methods. Based on this analysis, we recommend that three quantitative statistics, Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS), and ratio of the root mean square error to the standard deviation of measured data (RSR), in addition to the graphical techniques, be used in model evaluation. The following model evaluation performance ratings were established for each recommended statistic. In general, model simulation can be judged as satisfactory if NSE > 0.50 and RSR < 0.70, and if PBIAS + 25% for streamflow, PBIAS + 55% for sediment, and PBIAS + 70% for N and P. For PBIAS, constituent-specific performance ratings were determined based on uncertainty of measured data. Additional considerations related to model evaluation guidelines are also discussed. These considerations include: single-event simulation, quality and quantity of measured data, model calibration procedure, evaluation time step, and project scope and magnitude. A case study illustrating the application of the model evaluation guidelines is also provided.
9,386 citations
TL;DR: In this paper, a solution of the problem of determining the reservoir storage required on a given stream, to guarantee a given draft, is presented, where a long-time record of annual total...
Abstract: A solution of the problem of determining the reservoir storage required on a given stream, to guarantee a given draft, is presented in this paper. For example, if a long-time record of annual total...
5,087 citations
"Exploring Cooperative Transboundary..." refers background in this paper
...Siam and Eltahir (2017) noted an increased Hurst coefficient in over half of their bias-corrected GCM projections, and the assessment by Hurst (1951) emphasized that greater hydrologic persistence would require greater basin storage....
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2,186 citations
"Exploring Cooperative Transboundary..." refers background in this paper
...…met this minimum criterion, the most helpful or least harmful of remaining dimensions could be examined based on principles of minimax theorem (von Neumann, 1928), which seeks to minimize the possible loss (e.g., minimize losses of hydropower) for a worst case scenario (i.e., Ethiopia agreeing to…...
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TL;DR: A new duality betweenbounded and unbounded convex sets and hstars (a generalization of hyperbolas) and between Convex Unions and Intersections is found and motivates some efficient ConveXity algorithms and other results inComputational Geometry.
Abstract: By means ofParallel Coordinates planar “graphs” of multivariate relations are obtained. Certain properties of the relationship correspond tothe geometrical properties of its graph. On the plane a point ←→ line duality with several interesting properties is induced. A new duality betweenbounded and unbounded convex sets and hstars (a generalization of hyperbolas) and between Convex Unions and Intersections is found. This motivates some efficient Convexity algorithms and other results inComputational Geometry. There is also a suprising “cusp” ←→ “inflection point” duality. The narrative ends with a preview of the corresponding results inR
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1,434 citations
"Exploring Cooperative Transboundary..." refers background in this paper
...The results of eight objectives in Table 2 can be visualized using parallel plots (Inselberg, 1985) where each vertical axis represents an objective and each segmented line represents the performance of a particular management solution (Figure 8)....
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TL;DR: The objective of this paper is to review the state-of-the-art of mathematical models developed for reservoir operations, including simulation, which include linear programming, dynamic programming, nonliner programming, and simulation.
Abstract: The objective of this paper is to review the state-of-the-art of mathematical models developed for reservoir operations, including simulation. Algorithms and methods surveyed include linear programming (LP), dynamic programming (DP), nonliner programming (NLP), and simulation. A general overview is first presented. The historical development of each key model is critically reviewed. Conclusions and recommendations for future research are presented.
1,345 citations
"Exploring Cooperative Transboundary..." refers background in this paper
...We note that many previous studies have provided valuable insight into the benefits of cooperation through optimized system operations, yet translating optimized results into operational policies that specify dam operations is notoriously challenging (Yeh, 1985)....
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