Transboundary Basins Research Articles

Economic benefit evaluation of water resources allocation in transboundary basins based on particle swarm optimization algorithm and cooperative game model-A case study of Lancang-Mekong River Basin.

The present work aims to find the optimal solution of Nash Equilibrium (NE) in the traditional Game Theory (GT) applied to water resources allocation. Innovatively, this paper introduces Particle Swarm Optimization (PSO) into GT to propose a cooperative game model to solve the NE problem. Firstly, the basic theory of the PSO algorithm and cooperative game model is described. Secondly, the PSO-based cooperative game model is explained. Finally, the PSO-based cooperative game model is compared with the Genetic Algorithm (GA) to test the performance. Besides taking the countries in Lancang Mekong River Basin as the research object, this paper discusses each country’s water consumption and economic benefits under different cooperation patterns. Then, a series of improvement measures and suggestions are put forward accordingly. The results show that the average server occupancy time of the PSO-based cooperative game model is 78.46% lower than that of GA, and the average waiting time is 79.24% lower than that of the GA. Thus, the model reported here has higher computational efficiency and excellent performance than the GA and is more suitable for the current study. In addition, the multi-country cooperation mode can obtain more economic benefits than the independent water resource development mode. This model can quickly find the optimal combination of 16 cooperation modes and has guiding significance for maximizing the benefits of cross-border water Resource Utilization. This research can provide necessary technical support to solve the possible contradictions and conflicts between cross-border river basin countries and build harmonious international relations.

Trace metal concentrations, fluxes, and potential human health risks in West Africa rivers: a case study on the Bia, Tanoé, and Comoé rivers (Cote d'Ivoire).

Downstream water pollution resulting from anthropogenic pressures on upstream water can cause conflicts, especially in transboundary rivers basins. This study assessed trace metals cadmium, lead, copper, and iron total concentrations, fluxes, and the potential human health risks through ingestion or dermal contact of waters at the mouth of three West African transboundary rivers: the Comoé, Bia, and Tanoé rivers. The results showed highest total concentrations during the months of May and October and statistically comparable concentrations in the rivers. The fluxes discharged to the Atlantic Ocean through the Aby and Ebrie Lagoons are as high as average values found elsewhere in the World. Trace metals lead, copper, and iron fluxes were highest during the month of October in the Bia, Tanoé, and Comoé rivers. The cadmium flux was highest during the month of October in the Bia and Comoé rivers, and during the months of February and December in the Tanoé River, indicating that contamination came mainly from upstream waters and the draining of the river basins. The Pearson correlation analysis showed that the trace metals were mainly from anthropogenic sources including gold mining and agriculture. The total concentrations were lower than international guidelines set by the World Health Organization (WHO). However, the potential human health risk assessment results suggest a significant likelihood of community exposure to harmful effects but not to cancers through water ingestion. This work recommends including small rivers when assessing global river metal fluxes to the ocean and also reducing upstream inputs from human activities to mitigate downstream river water pollution.

Participatory design of robust and sustainable development pathways in the Omo-Turkana river basin

Study regionOmo-Turkana Basin, trans-boundary basin between Ethiopia and Kenya (North eastern Africa). Study focusSignificant investments in large dams have been mobilized in the Omo-Turkana basin to expand hydropower and support extensive irrigation projects. Assessing the impacts of these infrastructures, particularly on local stakeholders, constitutes a crucial foundation for socially inclusive as well as environmentally and economically sustainable development. This study showcases the potential of a participatory decision-analytic framework in investigating the impacts of alternative development pathways on competing stakeholders’ interests in the Omo-Turkana basin to support strategic planning under both current and projected hydroclimatic and socio-economic conditions. The optimal operation of the planned system expansion, including the current and future dam cascade and the irrigation projects, is investigated to provide insights into multisectoral trade-offs. Five main sectors with competing interests are considered: hydropower production, environmental protection, indigenous recession agriculture, fish yield in Lake Turkana, and large-scale commercial irrigated agriculture. New hydrological insights for the regionResults show that the planned infrastructure can negatively impact local stakeholders, particularly in terms of fish yields in Lake Turkana. Still, a potential exists for negotiating operational compromises that are both efficient and socially inclusive. Moreover, even though the performance of the planned infrastructure is expected to decline in the future under changing climate and irrigation demands, this can be mitigated by timely implementing robust solutions triggered by the alterations of streamflows in the northern part of the basin.

Characterising social-ecological drivers of landuse/cover change in a complex transboundary basin using singular or ensemble machine learning

Studies have focused on understanding land use/cover (LULC) change through regression techniques. However, machine learning (ML) techniques and their ensembles may provide more accurate results. Accurate determination of drivers of LULC can guide reliable land use planning and effective natural resource management. In this study, we tested the utility of ML techniques and ensemble modelling to explain the social-ecological drivers of LULC in the Okavango basin. The Deep Neural Network (DNN) coupled with climate-based regionalization of the study area were used for LULC classification of the years 2002, 2013 and 2020. Centroids of 22 LULC transitions of the same period were used to separately calibrate five (5) machine algorithms (namely Random Forests (RF), Gradient Boost Models (GBM) and Maximum Entropy (MaxEnt), Classification Tree Analysis (CTA) and their ensemble. Model performance was evaluated using the Receiver Operating Characteristic (ROC) and the True skill statistic (TSS). Variable importance was used to assess the contribution of social-ecological variables to each LULC transition. Variables that were determined to be driving LULC were then used to predict future LULC using the Artificial Neural Network and Cellular Automata (ANN-CA). Analysis results show that average LULC classification accuracy for the study period (2002, 2013 and 2020) was (Bsh Koppen zone; OA = 95.03, Kappa = 0.94), (Cwa Koppen zone; OA = 95.29, Kappa = 0.94), Cwb Koppen zone; OA = 96.04, Kappa = 0.95). The ML ensemble performed better (ROC> 95, TSS >87) than singular ML models based on two separate model evaluation metrics. The Random Forest classifier outperformed other singular ML (ROC = 90.41, TSS = 84.2). Based on the top-performing ensemble model, distance from rivers, population density, annual average temperature, drought severity, fire frequency and distance from towns influence the conversion of natural to anthropogenic LULC classes (importance >0.5). On the other hand, distance from rivers, soil organic carbon, precipitation, GDP, elevation, population density and annual average temperature importantly influenced conversion from one natural LULC class to another natural LULC class. The study revealed that natural classes (wetland, shrubland, water and woodlands) will gradually decrease at the expense of anthropogenic classes (built-up and cultivated) in future (2040). Despite proposing the necessity of a basin-wide land-use plan to minimise pressure on resources and ensure sustainable use, findings in this study illustrate the benefit of ensemble modelling in understanding LULC dynamics in transboundary basins.

Satellite observations reveal 13 years of reservoir filling strategies, operating rules, and hydrological alterations in the Upper Mekong River basin

Abstract. The current situation in the Lancang–Mekong River basin is emblematic of the issues faced by many transboundary basins around the world: riparian countries prioritize national water–energy policies and provide limited information on how major infrastructures are operated. In turn, such infrastructures and their management become a source of controversy. Here, we turn our attention to the Upper Mekong River, or Lancang, where a system of 11 mainstream dams controls about 55 % of the annual flow to Northern Thailand and Laos. Yet, assessing their actual impact is a challenging task because of the chronic lack of data on reservoir storage and dam release decisions. To overcome this challenge, we focus on the 10 largest reservoirs and leverage satellite observations to infer 13-year time series of monthly storage variations. Specifically, we use area–storage curves (derived from a digital elevation model) and time series of water surface area, which we estimate from Landsat images through a novel algorithm that removes the effects of clouds and other disturbances. We also use satellite radar altimetry water level data (Jason and Sentinel-3) to validate the results obtained from satellite imagery. Our results describe the evolution of the hydropower system and highlight the pivotal role played by Xiaowan and Nuozhadu reservoirs, which make up to ∼ 85 % of the total system's storage in the Lancang River basin. We show that these two reservoirs were filled in about 2 years and that their operations were marginally affected by the drought that occurred in the region in 2019–2020. Deciphering these operating strategies will help enrich existing monitoring tools and hydrological models, thereby supporting riparian countries in the design of more cooperative water–energy policies.

Basin-Wide Water Resources Management Strategies Improve Cooperation Effectiveness and Benefits

Basin-wide cooperation is an approach to resolve water disputes and improve the resilience of transboundary river basins to extreme droughts under climate change. However, the effectiveness of cooperation among various stakeholders has disputes in moving from theoretical research to practical application. This paper aims at developing basin-wide water resources management strategies to improve cooperation effectiveness in the Lancang-Mekong River Basin (LMB). An interdisciplinary physically based integrated hydroeconomic water system model is developed for strategy evaluation, and is shown to have good performance in reproducing historical events. First of all, we find that agricultural benefits in downstream countries are primarily affected by hydrological conditions, without significant impacts from reservoir construction. Second, the cooperative action—three-phase emergency water supply—by upstream reservoirs discharge can alleviate the agricultural drought of downstream countries, and it is further improved by better spatial and temporal water reallocation among different stakeholders. Last but not least, we characterize the cooperation effectiveness under different hydrological conditions by two indicators (i.e., incremental benefit and cooperation efficiency). They show two opposite trends: from extremely high-flow years to extremely low-flow years, the incremental benefit brought by basin-wide cooperation increases by nearly six times, whereas the cooperation efficiency (measured by how many times benefits are gained by downstream from upstream unit loss) decreases by 80 percent. This study provides guidance and support for transboundary basin cooperation and sustainable management.

Net carbon flux from cropland changes in the Central Asian Aral Sea Basin

The transboundary Aral Sea Basin (ASB) covers parts of the former Union of Soviet Socialist Republics (USSR), the central Asian portion of Kazakhstan (KAZ), Uzbekistan (UZB), Turkmenistan (TUK), Kyrgyzstan (KGZ), and Tajikistan (TAJ). During recent decades, the region has experienced widespread cropland changes and has therefore attracted attention. However, carbon flux caused by these changes, which is critical to understand the carbon cycle in the region and to develop strategies for carbon sequestration, has not been quantified. We applied the Bookkeeping Model to analyze carbon flux caused by cropland changes. We found that the cropland area expanded from 1975 to 2019. Prior to 1990, the net increment in cropland area was 64.47 kha yr−1; this decreased to 11.02–18.69 kha yr−1 after the collapse of the USSR (1991). Grasslands and bare lands with low carbon density were the main types of land that were converted to cropland, accounting for approximately 70.3–99.29% of the land cleared for cropland. In terms of cropland loss, grassland accounted for more than 40.69% of the cropland converted to other land cover types, followed by artificial surfaces, which accounted for 25.84–45.16%. The expansion of cropland served as a carbon sink owing to the increase in irrigation and fertilization. The overall potential carbon emission was −89.38 ± 35.34 Tg C, and contributions of the five countries were as follows: TUR (−33.65 ± 6.30 Tg C), UZB (−29.23 ± 25.35 Tg C), KAZ (−12.76 ± 12.16 Tg C), TAJ (−11.11 ± 5.47 Tg C), KGZ (−2.63 ± 7.83 Tg C). The net carbon flux was −2.04 ± 0.23 Tg C yr−1 before 1990, and it decreased to −1.87 ± 1.03 Tg C yr−1 during the post-Soviet era. Finally, we state sustainable agricultural management is urgently needed to deal with the environmental problems of the Aral Sea, which have been primarily caused by cropland expansion.

Study on Influencing Factors and Simulation of Watershed Ecological Compensation Based on Evolutionary Game

In the practice of watershed ecological compensation, due to the inconsistency between the interests of economic development and the objectives of ecological protection, there are typical game characteristics among the relevant stakeholders. Taking the ecological compensation between Henan and Shaanxi in the Yellow River Basin as an example, this paper constructs an evolutionary game model, obtains the external conditions for various stakeholders to achieve stable cooperation from the perspective of the government, and demonstrates the necessity of combining vertical and horizontal ecological compensation. The sensitivity of each party’s decision making to key elements is analyzed through a simulation. The results show that: (1) the optimal strategy is mainly affected by the initial willingness of the upstream government and the central government; the strong regulatory power of the central government can eliminate the influence of the initial will; (2) development opportunity costs and vertical fiscal transfer payments have the most obvious influence on upstream government decision-making; (3) the effect on optimal decision state of downstream paying upstream ecological compensation is higher than that of upstream paying downstream ecological compensation; (4) the punishment of the central government should ensure the binding force on the lower governments, and the revenue and expenditure under its supervision strategy should ensure the effectiveness of the supervision public power. The above conclusions provide support for improving the ecological compensation mechanism of transboundary basins.

Revisiting the Indus Basin Model for an Energy Sustainable Pakistan

Water is vital and an essential entity directly and indirectly for all living creatures from their birth, whereas electrical energy has a dominant role in the growth of society in general and for human beings in particular. Optimal use of water and production of electrical energy at minimum cost are potential research challenges. Hydraulic energy is one of the cheapest and the most exploited renewable energy resource for power generation worldwide, and is in line with the seventh United Nations Sustainable Development Goal (SDG 7). The Indus basin is a trans-boundary basin, and its modeling has been a source of interest for scientists and policymakers. Indus Basin Model Revised (IBMR) has many variants, all focusing on optimal use of water for irrigation purposes. In this paper, the modified IBMR model is proposed addressing both agriculture and power generation aspects simultaneously. This model optimizes the Consumer Producer Surplus (CPS) by considering different water inflow probabilities. A parameter has been introduced in the modified objective function to manipulate the supply of water to agriculture and hydropower generation. The proposed model has been implemented in Generic Algebraic Modeling System (GAMS) and case studies have been investigated in presence and absence of power generation. The results obtained show that, with incorporation of hydropower, basin wide income is increased up to 11.83% using 50% exceedance probability, and results are in agreement with reference power generation estimated by National Transmission and Dispatch Company (NTDC). The SDG 7 targets ensure the reasonable, dependable, sustainable and contemporary energy access to all. The current research is focusing on how Pakistan would achieve the SDG 7 targets. By 2040, it is anticipated that Pakistan’s energy mix will have around 40% of hydropower and 16% of renewable energy.

Reducing adverse impacts of Amazon hydropower expansion.

Proposed hydropower dams at more than 350 sites throughout the Amazon require strategic evaluation of trade-offs between the numerous ecosystem services provided by Earth's largest and most biodiverse river basin. These services are spatially variable, hence collective impacts of newly built dams depend strongly on their configuration. We use multiobjective optimization to identify portfolios of sites that simultaneously minimize impacts on river flow, river connectivity, sediment transport, fish diversity, and greenhouse gas emissions while achieving energy production goals. We find that uncoordinated, dam-by-dam hydropower expansion has resulted in forgone ecosystem service benefits. Minimizing further damage from hydropower development requires considering diverse environmental impacts across the entire basin, as well as cooperation among Amazonian nations. Our findings offer a transferable model for the evaluation of hydropower expansion in transboundary basins.

Water Quality Problems Analysis and Assessment of the Ecological Security Level of the Transboundary Ural-Caspian Basin of the Republic of Kazakhstan

Both the insufficiency of water resources and the contamination of even transboundary water bodies are serious problems. Water quality analyses of the transboundary (between Russia and Kazakhstan) Ural River and the Kazakh sector of the Caspian Sea, and their assessment are the main research questions of this study. It is shown that the Ural River is heavily contaminated by polychlorinated biphenyls, heavy metals, oil contaminants, and pesticides, arising from industrial enterprises and agricultural objects. The results show that these toxicants are not only present in water, but they are also accumulated in the muscular tissues of all fish (Abramis brama, Sander lucioperca, Aspius aspius). The Caspian Sea is heavily contaminated by petroleum hydrocarbons due to off shore oil production. A sufficiently high level of accumulation of petroleum hydrocarbons, organochlorine pesticides and heavy metals was determined in the muscles of Caspian fish. All these contaminations lead to the loss of biodiversity and bio-productivity of the Caspian Sea. The authors propose a methodology for a quantitative assessment of the environmental safety level in relation to the Kazakh part of the Caspian Sea, based on bioindication methods. Recommendations, aimed for maintaining acceptable values of water resources quality, are suggested.

Investigation of the Origin of Hueco Bolson and Mesilla Basin Aquifers (US and Mexico) with Isotopic Data Analysis

An important tool to identify the origin of a groundwater resource is the use of isotopic signatures. Isotopic signatures give us the age of water and provide information as to the water’s origin, potential transit at geologic structures, source of salinization, and possible recharge points. The purpose of this study was to collect and analyze well samples to evaluate isotopic tracers (δ18O and tritium) in the transboundary Conejos-Médanos/Mesilla aquifer located between the US and Mexico. This new analyzed information was compared with the isotopic information available in the US Mesilla and US-MX Hueco basins generated by previous works, which described the common origin of the Hueco Bolson and Mesilla Basins aquifers. This study used isotopic analysis to validate the theory of the original formation and interconnectivity of both transboundary basins. This research presents new data of δ18O and tritium, and a comparison with previous published data from other workers, versus the known global meteoric water line (GMWL) and the Rio Grande evaporation line (RGEL). Results show that the groundwater at the transboundary aquifer features an evaporated isotopic signal, which is consistent with referenced published data that discusses the geologic history of aquifer formations at the studied area. This study is important because isotopic studies from the area were nonexistent and because isotopic data can explain recharge scenarios that relate to groundwater quality.

Exploring the Spatio-Temporal Variability of Precipitation over the Medjerda Transboundary Basin in North Africa

Medjerda is a key transboundary watershed in the Maghreb region, crossing from the Algerian mountains through northern Tunisia. Therefore, the analysis of the rainfall regime in this basin is of paramount importance for water resources management and regional economic development, notably concerning agriculture. This study examines the rainfall trends over the Medjerda watershed on multi-temporal scales (monthly, seasonally and annually) with a database of monthly rainfall observed in 60 stations evenly spread over the watershed. After filling gaps and homogenizing data, the Mann–Kendall test for trend detection was applied to rainfall series and the Sen’s slope method was adopted to estimate the trend’s magnitude, interpolated over the sub-catchments, to analyze the spatial distribution of rainfall changes within the watershed. Results showed the absence of significant trends at the annual scale for the entire catchment. However, rainfall redistribution was observed throughout the year, with a notable precipitation reduction during spring and increased winter precipitation, which could impact agriculture and ecosystem functioning. This modification of the rainfall regime implies an adaptation of the management of dams and reservoirs, with a reduced filling capacity during spring in anticipation of the summer dry season.

Improving Transboundary Drought and Scarcity Management in the Iberian Peninsula through the Definition of Common Indicators: The Case of the Minho-Lima River Basin District

Drought is one of the most damaging natural hazards in the Iberian Peninsula, causing varied socioeconomic and environmental impacts. To prevent these impacts, there must be close cooperation between Portugal and Spain, as the two countries share five river basins. However, regarding drought planning and management the two countries are clearly in different stages. Portugal approved a national drought plan in 2017, while Spain has already had drought plans in place for all River Basin Districts since 2007 and approved an updated version of these plans in 2018. The Spanish drought plans currently in place foresee two sets of indicators: prolonged drought and scarcity indicators. This paper presents the definition of similar indicators for the Portuguese part of the shared Minho and Lima river basins, according to European guidelines and in common with Spain, with the aim of developing a joint international drought management plan for these basins. For the period from October 1980 to September 2017, the comparison of the indicators obtained for the Portuguese parts of the basins with the corresponding Spanish ones shows a similarity in the occurrence of drought and scarcity in both parts of the basins, although with a higher prevalence of scarcity situations in the Lima Spanish part. This work was developed in close collaboration with the River Basin District competent authorities of both countries, aiming to be a prototype for the definition of new and comparable drought and operational scarcity indicators. Therefore, this work is a starting point for the creation of common tools for integrated drought management of transboundary basins in the IP.

Optimal allocation and transaction of waste load permits for transboundary basin: A Bi-level programming approach based on node-arc

Inadequate water quality exacerbates global water resources scarcity. Hence, water quality of the river basin is increasingly perceived as a global obstacle to sustainable development because of the limited water carrying capacity. Efficient waste load permits (WLPs) allocation plays a critical role in enhancing water quality by controlling the emission cap. Considering transboundary water pollution and transaction among regions, a bi-level objective model is proposed to analyze the WLPs allocation based on the node-arc method. Motivated by alleviating regional development differences, the watershed management committee concentrates on equitable distribution of WLPs to regions. Furthermore, regional authorities focus on how to guarantee the maximum economic development and balance the WLPs emissions from the municipal, industrial, and agricultural sectors. Practicality and efficiency of the constructed model is demonstrated by applying it to Tuojiang River Basin. Through the analysis of the results, three management recommendations are proposed for Tuojiang River: strengthening the prevention of agricultural non-point source pollution, sticking to the cooperation between upstream and downstream regions, and speeding up the construction of sewage environmental tax system. The results illustrate that as the proposed method can control the total amount of sewage, it could provide decision-making references for the amelioration of water environment.

Virtual stakeholder engagement for transboundary water management: approach, challenges, and limitations

Water security is a complex challenge in transboundary basins: competing upstream-downstream demands and the pursuit of sovereign interests are key factors often responsible for fragmented water resource management. Designing a transboundary structure under these conditions requires common interests from which each country can benefit. On the Ruzizi River, which delimits the border between Rwanda and the Democratic Republic of Congo (DRC) upstream and between the DRC and Burundi downstream, two structures have already been built. The three riparian countries have been engaged since 1976 within the Economic Community of the Great Lakes Countries. It is through this body that the three member states decided to build a third dam to complete the cascade. TRACTEBEL is involved through a climate change resilience assessment which requires stakeholder engagement from the three countries. While stakeholder engagement is generally a difficult exercise, the process has been exacerbated by the COVID-19 epidemic. To adapt, the TRACTEBEL team proposed virtual workshops for local stakeholders, as well as the launch of a project website to encourage maximum interaction. The challenges and limitations of these solutions will be presented. This approach is the first step towards establishing a sustainable governance of the Ruzizi cascade.

Spatio-temporal analysis of remotely sensed rainfall datasets retrieved for the transboundary basin of the Madeira River in Amazonia

Rainfall is recognized as the most important driving force of the hydrologic cycle. To accurately represent the spatio-temporal rainfall variability continues to be an enormous hydrological task when using commonly sparse, if available, rain gauges networks. Therefore, the present study devoted a special effort to analyze the robustness of some satellite rainfall products, notably the datasets hereafter named as (i) CHIRP (Climate Hazards Group InfraRed Precipitation), (ii) CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data), (iii) 3B42, and (iv) 3B42RT of the Tropical Rainfall Measuring Mission (TRMM), to adequately represent the pluviometric regime in the Madeira river basin. To assess the accuracy of acquired remotely sensed rainfall products, comparisons to observational available rain gauges usually taken as ground-truth in the literature, despite their well-known limitations, were performed. Wavelet analysis was also used to validate the performance of the referred satellite products by means of extracting the corresponding cycles, frequencies, and tendencies along the available time series across the studied basin. The results showed that the data sources CHIRPS and CHIRP better represent the pluviometric phenomenon by means of their monthly accumulated rainfall in the Madeira river basin when compared to the 3B42 and 3B42RT products taking into account rain gauges as baseline information. The CHIRPS product performed the best among the selected rainfall estimators for the Madeira river basin. Further analysis brought up also another very interesting result related to non-rainfall periods, which is usually not reported. However, such evaluation is quite important in hydrology when examining run sequences of droughts and consequent effects in the water balance at the watershed scale. Highly accurate estimates in the sense of identifying non-rainfall periods by remotely sensed information was achieved, which represents an additional and valuable asset of satellite rainfall products. It is worthwhile to say that this perspective deserves to receive much more attention in the literature in order to deeply discuss the water-energy-food nexus.

Ecosystem service products trading in the transboundary basin of the Yangtze River Delta: An example of Tianmu Lake Basin

Ecosystem service products trading in the transboundary basin of the Yangtze River Delta: An example of Tianmu Lake Basin

Assessment of water quality dynamics in the transboundary basin of the Ural River

Assessment of water quality dynamics in the transboundary basin of the Ural River

Transboundary water treaty design for poverty reduction and climate adaptation

When transboundary basins are developed in poor regions where freshwater resources are fully committed, it becomes important to design economically sustainable action plans to address existing poverty, especially in responding to mounting evidence of climate change and population growth. Increasing competition over shared water resources as well as climate water stress has attracted research efforts internationally addressing the benefits and costs of establishing water-sharing treaties. Despite this ongoing interest, few peer-reviewed works have investigated water development and use patterns that could produce economic gains for all parties from establishing transboundary water sharing agreements. This work develops an approach to address the gap by formulating and applying a basin-scale hydro-economic optimization model of West Africa’s Volta River Basin. The work analyzes the effects of a prospective multilateral water allocation and hydropower trade agreement on the size, sign, and distribution of basin-wide economic benefits. The model includes two new large storage reservoirs, five water use purposes, and two climate water supply scenarios with and without a water sharing treaty. From that, it assesses the net economic benefit-maximizing patterns of water use with and without the treaty. Results show a Pareto Improving outcome is achievable for all riparian countries from new storage capacity in the basin for which at least one country is better and none is worse off. This improvement is achievable with a multilateral water sharing treaty implemented with power trading among the six basin countries. Results indicate that all basin countries have the potential to secure significant economic gains from additional hydropower production with the treaty. Under its implementation, upstream countries would reduce agricultural water use in exchange for higher valued hydropower benefits under the climate-stressed low flow scenario. Despite potential benefits that are shareable from negotiation, practical implementation of such a treaty will require considerable diplomatic skill, patience and effort.