Transboundary River Basins Research Articles

Application of precipitation products for flood modeling of transboundary river basin: a case study of Jhelum Basin

The main objective of this study is the flood modeling of the River Jhelum Basin in the Jammu and Kashmir using the Integrated Flood Analysis System (IFAS) hydrological model. The region having an area of 33,000 km2 has a limited rain gauge coverage. The data inaccessibility is accentuated due to the mountainous topography, glaciers, and remote areas. This research makes innovative use of the Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation (APHRODITE) dataset to overcome the data scarcity for the basin. For flood modeling, a regionalized approach was adopted, whereby the four main tributaries of the River Jhelum Basin were separately modeled. The parameters, thus, determined, were later used in the modeling of the River Jhelum, the main river of the basin. The model was calibrated on the medium-high flood of 2010 and validated on the very high flood of 2014, obtaining good results as indicated by Nash–Sutcliffe Model Efficiency Coefficient (NSE) of 0.77. Later, the model was executed using the Global Satellite Mapping of Precipitation (GSMaP). It performed adequately for the high flood event of 2014, while for the flood of 2010, it gave poor results. Besides, this study also demonstrates the efficacy of a new generation of computer models that work by accessing the free global datasets available on the web for hydrological modeling.

The role of proportionality in the law of transboundary waters

Equitable and reasonable utilization, the core substantive rule of the law of transboundary waters, requires the utilization of transboundary waters by States, considering the needs and interests of other States. This implies that the uses and benefits of transboundary waters should be shared in proportion to each basin State’s needs. Such needs are calculated through the consideration and balancing of factors associated with the rule of equitable and reasonable utilization. However, the formulation of the rule in the 1997 Convention on the Law of the Non‐navigational Uses of International Watercourses does not prescribe how the balancing between competing needs of the transboundary watercourse States may be achieved. This article argues that the principle of proportionality can play a role in facilitating the equitable balancing between the competing needs of States in transboundary river basins. Proportionality can also play a role in informing the balancing inherent in other substantive and procedural rules and dispute resolution in the law of transboundary waters. The article further examines the role of proportionality in benefit‐sharing practices in transboundary river basins, where States have adopted a proportionate cost–benefit‐sharing approach. The article uses China as an example to understand the role of proportionality in informing Chinese transboundary water treaties.

Assessing the Anthropogenically Caused Pollution of Water Bodies Within the Selenga River Basin on the Territory of Mongolia and Russia

Presented are the results from studying the current state, modeling and forecasting of the transboundary transport of pollutants with the flow of the rivers within the Selenga river basin. The method for calculating the pollution coefficient was used to assess the degree of pollution of the Selenga river basin on the territories of Mongolia and the Republic of Buryatia (RF) on the linear sections of the river and its tributaries within the boundaries of the adjacent river sections according to data of state monitoring observation in both countries. Results from assessing the impact of economic entities located within the transboundary Selenga river basin on the streams according to the α-indicator of the pollution coefficient and subsequent ranking by four levels of pollution indicate that the catchment and Lake Baikal itself continue to be polluted by insufficiently treated wastewater from industrial enterprises and housing and communal services. Calculations showed that the aquatic ecosystems of the Kyakhtinka (Khiagt), Modonkul’ Selenga rivers in the border zone along the border of Russia and Mongolia in the area of Naushki – Sukhbaatar and Kyakhta ‒ Altanbulag, and in the area of the settlement of Novoselenginsk are most disturbed. On the territory of the Russian part of the basin, the Selenga river downstream, the degree of water pollution is increasing in the areas of industrial centers, such as Gusinoozersk and Ulan-Ude. The average indicator of the pollution coefficient as calculate for the Russian part of the Selenga river basin was higher than that for the Mongolian part, which suggests the conclusion that the degree of pollution by the pollutants under consideration is higher on the Mongolian territory than on the Russian territory.

An Innovative Holistic Approach to an E-flow Assessment Model

River water resources provide a wide range of necessary ecosystem services, including regulating, provisioning, supporting and cultural services. Ecosystem services are linked to an appropriate level of functionality of river water resource processes, which can be connected with river basin environmental objectives. Environmental objectives can be achieved only if appropriate flow and sediment regimes and related river morphology quality are guaranteed. The obligation to define environmental flow (E-flow) in the European Union Water Framework Directive European (WFD) is not explicit, and the implementation of the WFD is more focused on water quality. Considering the specific climatic, hydrographic and hydrological conditions and the definition of E-flow, each EU country has developed procedures for their investigation and determination. In the Republic of Croatia, no methodology has been elaborated, nor is there any legal regulation to define E-flow downstream of a dam or water intake site. This paper presents the significant pressures that have affected the transboundary rural Sutla River basin between Croatia and Slovenia. These pressures can cause changes in the hydrological regime and biological elements of water quality. The holistic approach defines the E-flow for a profile on the Sutla River by linking hydrological, morphological, and ecological characteristics based on the exploration of the Sutla River and its biological communities. The full implementation of a holistic approach and the transition to Level III of the E-flow definition requires the enhancement of exploratory hydrological and biological monitoring that enables the use of habitat modelling. Doi: 10.28991/cej-2020-03091611 Full Text: PDF

Current assessment of species composition and biological characteristics of fishes in the transboundary rivers in Turkey

The freshwater fishes of Turkey have been studied for more than 150 yr. However, a nation-wide inventory of freshwater fish occurrences in all transboundary river basins (Euphrates–Tigris, Coruh, Kura–Araks, Maritsa and Orontes) has been neither studied nor published. This work is the first extensive study of the composition and biological characteristics of the freshwater fish fauna of the transboundary rivers in Turkey, with special reference to the native and non-native status of species, and the spatial patterns of species e.g., abundance category, endemism, main threats, movement patterns, habitat guild, feeding guild, and reproductive guild. It is determined that a total of 184 fish species in 25 families (including 15 species which are not native, and 30 species are considered as endemic) live in the transboundary river basins in Turkey. Of the 184 fish species: 19 species are abundant, 57 species decrease, and 101 species are data deficient based on IUCN Red List (International Union for Conservation of Nature and Natural Resources). One of the main threats to freshwater fish occurrences in all transboundary river basins are dams. Most fish species in the area are threatened by dams, water extraction, and habitat degradation.

Multiple drivers of hydrological alteration in the transboundary Srepok River Basin of the Lower Mekong Region

Human-induced changes in land and water resources adversely affect global hydrological regimes. Hydrological alteration of the natural flow regime is considered to have a significant damaging and widespread impact on river ecosystems and livelihoods. Therefore, understanding the hydrological alteration of rivers and the potential driving factors affecting such alterations are crucial to effective water resources management. This study analyses the impact of changes in land use, climate, and hydropower development on the hydrological regime of the Srepok River Basin in the Lower Mekong Region. The Lower Mekong Basin (LMB) in Southeast Asia is known for its agriculture, forests, fisheries, wildlife, and diverse natural ecosystems. Historical land use and climate change are quantified (utilising European Space Agency land cover and observed meteorological data) and correlated with the hydrological indicators using the Indicators of Hydrologic Alteration (IHA) software. Moreover, pre and post impacts on the hydrological regime by hydropower development are quantified using the Range of Variability Approach (RAV) in IHA software. The results reveal that land use, rainfall, and temperature affect different aspects of the hydrological regime, with corroborating evidence to support variation among the most correlated IHA and environmental flow component (EFC) parameters with the three drivers. The highest and lowest correlations among the IHA and EFC parameters under each driver are against land use (0.85, −0.83), rainfall (0.78, −0.54), and minimum and max temperatures (0.42, −0.47). Among the parameters, the fall rate has the most significant effect on hydrological alteration of all drivers. Hydropower development in the basin mostly affects the fall rate and reversal. Identifying the connection between these multiple drivers and hydrological alteration could help decision-makers to design more efficient and sustainable water management policies.

Havza Yönetiminde Bölgesel Elektrik Ticareti Modeli: Aral ve Kura-Aras Havzaları Üzerine Bir Değerlendirme

Transboundary river basin management problems have been on top of the agenda of Central Asian politics, especially after the dissolution of the Soviet Union. This issue area has was given priority in the global political-environmental debates since the emergence of the Aral Sea problem during the Soviet era. In contrast, the environmental issues regarding the Kura-Araks river basin were relatively less discussed in the literature and thus have been paid less attention in the global political -environmental debates. This paper compares the environmental and economic issue areas of the water management and hydroelectricity generation in the Kura-Araks river basin and the Aral Sea basin and recommends solutions based on dyad-level regional electricity trade schemes based on regional cooperation models.

A computationally efficient flash flood early warning system for a mountainous and transboundary river basin in Bangladesh

Abstract A computationally efficient early warning technique is developed for forecasting flash floods during the pre-monsoon season that are associated with a complex topography and transboundary runoff in northeastern Bangladesh. Locally conditioned topographic and hydrometeorological observations are key forcings to the modeling system that simulate the hydrology and hydraulic processes. The hydrologic model is calibrated and validated using satellite-based observations to estimate the correct amount of transboundary and mountainous inflow into the flash flood-prone plains. Inflow is then forecasted using precipitation forecast from a global numerical weather prediction (NWP) system called the Global Forecasting System (GFS). The forecasted inflows serve as the upstream boundary conditions for the hydrodynamic model to forecast the water stage and inundation downstream in the floodplains. A real-time in-situ data-based error correction methodology is applied to maintain the skill of the system. The simulation grid size and time-step of the hydrodynamic model are also optimized for computational efficiency. Historical performance of the framework revealed at least 60% accuracy at 5-day lead-time in delineating flood inundation when compared against Sentinel-1 synthetic aperture radar (SAR) imagery. The study suggests that higher resolution topographic information and dynamically downscaled meteorological observations can lead to significant improvement in flash flood forecasting skills.

Contested governance of drinking water provisioning services in Nepal’s transboundary river basins

Governance and management of ecosystem services involve a diversity of institutional mechanisms and policy processes from voluntary to regulatory and collaborative approaches. The governance structures and policy processes are often contested, particularly when stakeholder concerns are insufficiently addressed, particularly of those who are most affected by policy decisions. This research examines how collaborative governance enables the ecosystem services approach to source water protection, thereby addressing contested governance problems and policy processes in transboundary river basins in central Nepal. The data were collected using key informant interviews, policy workshops, policy document review, and direct observation. Research results suggest that the state established collaborative governance institutions to improve already adversarial situations rather than in the co-management of water provisioning and other ecosystem services. We conclude that collaborative governance should focus on empowering vulnerable communities to speak for themselves and for the natural environment, particularly to maintain the sustainable flow of multiple ecosystem services for current and future generations.

Addressing the supply-demand gap in shared rivers using water diplomacy framework: utility of game theory in the Indus river within Pakistan

Abstract The question of how to govern and manage transboundary river basin for competing and often conflicting demands due to limited supplies continues to be an issue of concern, conflict, and cooperation. A key novelty of this paper is the use of the Water Diplomacy Framework (WDF) to address supply-demand mismatch using the notion of collaborative problem-solving and joint fact-finding. It builds on innovative applications of game-theoretic approaches and uses equity and sustainability as guiding principles to address the supply-demand mismatch. Five different bankruptcy methods (net benefit ranges between US$17,462M to US$18,201M) and the Nash Bargaining Solution (net benefit ranges between US$18,132M to US$19,216M) are used to resolve supply-demand mismatch in the Indus basin among four provinces within Pakistan. The maximum total benefit generated from the Nash Bargaining Solution is 5.5% higher compared to the best bankruptcy method. Moving from the non-cooperative and rule-based bankruptcy methods to the Nash Bargaining Solutions provided increased benefit for all stakeholders. Reallocation of these increased benefits among the four provinces is done by applying the Nash Bargaining Solutions for homogenous and heterogeneous weights. These findings suggest that aspects of WDF – cooperative problem-solving approaches involving joint fact-finding and exploring different options – has the potential to simultaneously resolve supply-demand mismatch and generate more benefits for all stakeholders.

Hydrochemical composition and potentially toxic elements in the Kyrgyzstan portion of the transboundary Chu-Talas river basin, Central Asia

Water chemistry and the assessment of health risks of potentially toxic elements have important research significance for water resource utilization and human health. However, not enough attention has been paid to the study of surface water environments in many parts of Central Asia. Sixty water samples were collected from the transboundary river basin of Chu-Talas during periods of high and low river flow, and the hydrochemical composition, including major ions and potentially toxic elements (Zn, Pb, Cu, Cr, and As), was used to determine the status of irrigation suitability and risks to human health. The results suggest that major ions in river water throughout the entire basin are mainly affected by water–rock interactions, resulting in the dissolution and weathering of carbonate and silicate rocks. The concentrations of major ions change to some extent with different hydrological periods; however, the hydrochemical type of calcium carbonate remains unchanged. Based on the water-quality assessment, river water in the basin is classified as excellent/good for irrigation. The relationship between potentially toxic elements (Zn, Pb, Cu, Cr, and As) and major ions is basically the same between periods of high and low river flow. There are significant differences between the sources of potentially toxic elements (Zn, Pb, Cu, and As) and major ions; however, Cr may share the same rock source as major ions. The risk assessment revealed low non-carcinogenic and carcinogenic risks for human health; however, the maximum carcinogenic risk for As exceeded the allowable value, which requires further consideration. These results provide a scientific basis for the management of agricultural irrigation uses and also infill existing gaps regarding the hydrochemical composition in the Chu-Talas river basin, Central Asia.

The Nile Water-Food-Energy Nexus under Uncertainty: Impacts of the Grand Ethiopian Renaissance Dam

AbstractAchieving a water, food, and energy (WFE) nexus balance through policy interventions is challenging in a transboundary river basin because of the dynamic nature and intersectoral complexity...

Improving Reservoir Outflow Estimation for Ungauged Basins Using Satellite Observations and a Hydrological Model

AbstractNowadays, most of rivers globally are regulated by dams and reservoirs, which have substantially altered natural streamflow regimes. Understanding the impacts of these dams and reservoirs on streamflow is essential for water resources management. In situ reservoir release data or actual reservoir operating rules are difficult to obtain, particularly for transboundary rivers, resulting in the tremendous difficulty of simulating exact reservoir behaviors. This study aims to use easy‐to‐obtain satellite observations combined with a distributed hydrological model to estimate reservoir releases at the daily time scale. The developed Satellite‐Based Reservoir routing Scheme (SBRS) was applied to two individual reservoirs in the United States and Thailand and cascade reservoirs on the Lancang River in China. The normalized root‐mean‐square error (NRMSE), correlation coefficient (CC), and hydrographs of daily regulated streamflow simulations were used to assess the performance of the reservoir release simulations. The SBRS was compared with four other global reservoir operation schemes and showed better overall performance with higher CC and lower NRMSE. In addition, the SBRS performed better for the individual reservoirs (CC > 0.6, NRMSE < 0.2) than the cascade reservoirs, which is attributed to the uncertainty in the simulation of inflow and reservoir storage changes and to the lack of remote sensing data for all the cascade reservoirs. This study explores the potential of satellite observations combined with hydrological modeling in elucidating reservoir behaviors in ungauged and/or transboundary river basins. A better understanding of reservoir behaviors serves as a basis for water resources management and provides a more cooperative environment for all stakeholders of a basin.

Addressing knowledge gaps for transboundary environmental governance

Knowledge is widely considered a key ingredient for the effective and sustainable governance of the environment. In transboundary settings – i.e., where political boundaries cross natural resource system boundaries – there are considerable barriers to knowledge production and use. Resulting knowledge gaps can be barriers to governance. This research examines three case studies in which international river basin organizations, tasked with facilitating cooperation in transboundary river basins, recognized and addressed knowledge gaps to support governance of shared waters. We synthesize across the three case studies to develop a typology of knowledge gaps and the strategies used to address those gaps. In identifying common types of knowledge gaps and the on-the-ground strategies used to fill them, this research provides an important framework for assessing and theorizing knowledge at the transboundary scale, as well as useful recommendations and examples for practitioners seeking to develop that knowledge.

Impacts of climate change and reservoir operation on streamflow and flood characteristics in the Lancang-Mekong River Basin

The Lancang-Mekong River Basin (LMRB) is one of the most important transboundary river basins in Asia. While climate change perturbs the streamflow and affects flood events, reservoir operation may mitigate or aggravate this impact. Therefore, quantitative assessment of the climate change impact and reservoir effect on the LMRB is a vital prerequisite for future hydropower development and environmental protection. This study aimed to estimate the variation of the streamflow and flood characteristics affected by climate change and reservoir operation within the LMRB. A reservoir module was incorporated into the Variable Infiltration Capacity (VIC) model to simulate the streamflow susceptible to the reservoirs. It was found that the reservoirs had a substantial influence on the streamflow during 2008–2016, when many reservoirs were constructed in the LMRB. The reservoirs across the Lancang River (the upper Mekong River located in China) reduced the annual average streamflow by 5% at Chiang Sean station (northern Thailand) in 2008–2016, whereas their influence became undetectable downstream of Vientiane station (northern Laos). The streamflow changes downstream of Mukdahan station at southern Laos (including the stations in Cambodia and southern Vietnam) were mainly attributed to the local reservoirs and climate change. Compared with the baseline period of 1985–2007, the upstream reservoir operation dramatically affected streamflow at the midstream stations with higher dry season streamflow (+15% to +37%), but lower wet season streamflow was less affected (−2% to −24%) in 2008–2016. Climate change increased the magnitude and frequency of the flood by up to 14% and 45%, respectively, whereas the reservoir operation reduced them by 16% and 36%, respectively. Our findings provide insights into the interaction between climate change and reservoir operation and their integrated effects on the streamflow, informing and supporting water management and hydropower development in the LMRB.

River Water Quality of the Selenga-Baikal Basin: Part II—Metal Partitioning under Different Hydroclimatic Conditions

The partitioning of metals and metalloids between their dissolved and suspended forms in river systems largely governs their mobility and bioavailability. However, most of the existing knowledge about catchment-scale metal partitioning in river systems is based on a limited number of observation points, which is not sufficient to characterize the complexity of large river systems. Here we present an extensive field-based dataset, composed of multi-year data from over 100 monitoring locations distributed over the large, transboundary Selenga River basin (of Russia and Mongolia), sampled during different hydrological seasons. The aim is to investigate on the basin scale, the influence of different hydroclimatic conditions on metal partitioning and transport. Our results showed that the investigated metals exhibited a wide range of different behaviors. Some metals were mostly found in the dissolved form (84–96% of Mo, U, B, and Sb on an average), whereas many others predominantly existed in suspension (66–87% of Al, Fe, Mn, Pb, Co, and Bi). Nevertheless, our results also showed a consistently increasing share of metals in dissolved form as the metals were transported to the downstream parts of the basin, closer to the Lake Baikal. Under high discharge conditions (including floods), metal transport by suspended particulate matter was significantly greater (about 2–6 times). However, since high and low water conditions could prevail simultaneously at a given point of time within the large river basin, e.g., as a result of on-going flood propagation, snap-shot observations of metal partitioning demonstrated contrasting patterns with domination of both particulate and dissolved phases in different parts of the basin. Such heterogeneity of metal partitioning is likely to be found in many large river systems. These results point out the importance of looking into different hydroclimatic conditions across space and time, both for management purposes and contaminant modeling efforts at the basin scale.

Application of remote sensing techniques for analyzing operation of upstream reservoirs in transboundary river basins of Vietnam

Application of remote sensing techniques for analyzing operation of upstream reservoirs in transboundary river basins of Vietnam

International Environmental Conflict Management in Transboundary River Basins

Despite signing a bilateral water treaty in 1973, water utilization in the Hirmand River Basin (HRB) has been a source of dispute between Iran and Afghanistan for many decades. While Iran accuses Afghanistan of depriving it of the Hirmand water due to dam construction in the upper basin, Afghanistan assures that it enforces the treaty. An evident reduction of the Hirmand River flow to Iran in recent years is fully attributed by Afghanistan to a reduction in precipitation in the basin. Although Iran disagrees and remains unconvinced by this line of reasoning. A fundamental lack of trust in collected and shared hydrological data has hindered dialog between the two neighbors. To address this issue, this study investigates the use of remote sensing information, as an independent source of data, for fact-finding in a highly disputed transboundary river basin. For this purpose, historical data (34 years) from two satellite precipitation products, PERSIANN-CDR and CHIRPS, were used to understand if precipitation characteristics and, subsequently, rainfall-runoff regimes have changed in the HRB. Results reveal that the frequency and amount of heavy precipitation have been increasing over the mountainous areas. The total amount of precipitation has been increasing significantly. The intensity of heavy precipitation, however, has been decreasing over the basin. In the upper basin, the duration of the wet period has increased, although the share of wet months in annual precipitation has been decreasing. In the lower basin, trends in seasonal and annual precipitation and most of the indices are insignificant, indicating water availability issues cannot be attributed to the changes in precipitation in the downstream area itself. These results can be used as an integral part of mutual fact-finding and trust-building exercise that supports water diplomacy to promote environmental cooperation between Iran and Afghanistan.

Simulation of streamflow and instream loads of total suspended solids and nitrate in a large transboundary river basin using Source model and geospatial analysis

The management of LULC changes in transboundary river basins continues to challenge water resources managers due to the differences in development and conservation priorities of the countries sharing the basin. While various watershed models (WMs) exist to support decision making, basin-wide sustainable application of the instituted WM depends on the management priorities, resources, data availability, and knowledge gaps at national and sub-basin levels. Building on the results of our prior comparative analysis of WMs for a large transboundary river basin, we applied the ‘Source’ model to the Lower Mekong Basin (LMB). The constructed LMB-Source model was evaluated based on its streamflow and instream total suspended solids (TSS) and nitrate loads simulative performances. A combination of predictive performance metrics (PPMs) and sophisticated hydrologic signatures were used to calibrate model parameters and diagnose the model performance. Calibration results indicated strong similarity between the simulated and observed time series data and were further confirmed by the validation results. The successful model calibration generated parameters that represent hydrologic response characteristics (HRCs) and overland TSS and nitrate generation and removal dynamics (GRDs) previously not available for the LMB. The HRCs and GRDs can be regionalised with physical attributes of the LMB in future studies which can be used to support the management of ungauged sub-basins. This study confirms Source's capability as a decision support tool for the management of transboundary river basins, and provides basin-specific values of HRCs and GRDs that can be used for a better evaluation of the potential effects of LULC changes.

Future Transboundary Water Stress and Its Drivers Under Climate Change: A Global Study.

Various transboundary river basins are facing increased pressure on water resources in near future. However, little is known ab out the future drivers globally, namely, changes in natural local runoff and natural inflows from upstream parts of a basin, as well as local and upstream water consumption. Here we use an ensemble of four global hydrological models forced by five global climate models and the latest greenhouse‐gas concentration (RCP) and socioeconomic pathway (SSP) scenarios to assess the impact of these drivers on transboundary water stress in the past and future. Our results show that population under water stress is expected to increase by 50% under a low population growth and emissions scenario (SSP1‐RCP2.6) and double under a high population growth and emission scenario (SSP3‐RCP6.0), compared to the year 2010. As changes in water availability have a smaller effect when water is not yet scarce, changes in water stress globally are dominated by local water consumption—managing local demand is thus necessary in order to avoid future stress. Focusing then on the role of upstream changes, we identified upstream availability (i.e., less natural runoff or increased water consumption) as the dominant driver of changes in net water availability in most downstream areas. Moreover, an increased number of people will be living in areas dependent on upstream originating water in 2050. International water treaties and management will therefore have an increasingly crucial role in these hot spot regions to ensure fair management of transboundary water resources.