River Basin Research Articles

Variations in liver histology and P-gp expression among fish species in Doce River Basin, Brazil: implications for pollution sensitivity.

Fish may have different sensitivity to pollutants present in the water. We analyzed the liver histology, and P-gp expression in six species of fish from the Doce River basin. Fish were caught at six different points in the Doce River, and liver samples were taken for histological analysis. P-gp expression was analyzed using an immunohistochemical technique. In Astyanax lacustris, Hoplias intermedius, Hypostomus affinis, Trachelyopterus striatulus and Oligosarcus acutirostris, a double arrangement of hepatocyte plates was generally observed (tubular-form), while in Deutorodon taeniatus, a single arrangement of hepatocyte plates was frequently observed (cord-like). Histological changes, such as cytoplasmic vacuolation and nuclear alteration, were observed in the livers of all species analyzed, however, the species A. lacustris (34.1%) and H. affinis (33.3%) were those with the fewest individuals with histological changes. The H. intermedius, T. striatulus, and O. acutirostris were the species that presented more than 80% of their individuals with histological changes. The A. lacustris and H. affinis were the species that showed the highest P-pg immunolabeling in the liver, while the T. striatulus and O. acutirostris had the lowest levels. These results support the hypothesis that levels of P-gp expression could respond to the resistance or sensitivity of each species to environmental pollutants.

Fish fauna of the Upper Grande River basin: checklist and distribution patterns

ABSTRACT The Neotropical region exhibits a remarkable diversity of freshwater fish, with the Upper Grande River in the La Plata basin emerging as a significant yet underexplored hotspot. However, this region is confronted with escalating threats from human activities, such as hydroelectric damming and urbanization, which jeopardize its ichthyofauna. This research conducted a comprehensive inventory of the ichthyofauna in the Upper Grande River, covering diverse environments and sub-basins. Fish sampling at 185 sites revealed over 94 species, indicating a high richness and abundance of migratory fish, as well as the presence of two endangered species. While the study provides valuable insights into fish species richness and distribution, accumulation curves suggest the need for additional sampling efforts. The presence of non-native species, especially in the Aiuruoca and Grande sub-basins, raises conservation concerns. The study underscores the Upper Grande River’s critical role as an area for fish diversity, emphasizing the necessity for ongoing monitoring, conservation efforts, and additional sampling to fully uncover the extent of its ichthyofauna.

Dynamic evolution and influencing factors of green total factor productivity in the Yangtze River Economic Belt: a study based on the three-stage SBM-ML index model

Achieving sustainable development that harmonizes environmental protection with economic growth in the Yangtze River Economic Belt (YREB) remains a critical area of research. Examining green total factor productivity (GTFP) aids in pinpointing the key factors and pathways essential for fostering green economic development. On the basis of 108 prefecture-level cities in the YREB, a three-stage SBM-ML index model was constructed to measure the GTFP level from 2009 to 2022. ArcGIS software was used to analyze the spatiotemporal evolution of GTFP dynamically. Finally, the multidimensional factors affecting GTFP were systematically analyzed via the Tobit model. The study revealed that (1) GTFP exhibits notable spatial disparities among the upper, middle, and lower reaches of the YREB, with the downstream areas showing higher levels than the upstream and midstream areas do. (2) After excluding environmental factors and random errors, the true GTFP level significantly decreases, indicating a notable environmental masking effect, with a masking effect of up to 63.9%. (3) The spatial distribution of GTFP overall shows a “low-high-low-high” pattern from west to east, forming an “N”-shaped spatial pattern. (4) The Tobit model regression results show that government governance enhances GTFP, while economic growth and intergovernmental fiscal decentralization hinder real GTFP. Although urbanization was initially insignificant, it significantly boosted real GTFP post-COVID-19. Finally, policy recommendations to promote green development in river basins are proposed.

Prediction of non-stationary daily streamflow series based on ensemble learning: a case study of the Wei River Basin, China

Prediction of non-stationary daily streamflow series based on ensemble learning: a case study of the Wei River Basin, China

Multivariate drought indices to analyse spatiotemporal drought propagation in a semi-arid river basin

Multivariate drought indices to analyse spatiotemporal drought propagation in a semi-arid river basin

De novo assembly of a near-complete genome of aquatic vegetable Zizania latifolia in the Yangtze River Basin

The cultivated Zizania latifolia, an aquatic vegetable prevalent in the Yangtze River Basin, represents a unique plant-fungus complex whose domestication is associated with host-parasite co-evolution. In this study, we present a high-quality, chromosome-scale genome assembly of cultivated Z. latifolia. We employed PacBio long-read sequencing and Hi-C technology to generate ~578.42 Mb genome assembly, which contains 47.59% repeat sequences with a contig N50 of ~33.75 Mb. The contigs were successfully clustered into 17 chromosomal-sized scaffolds with a GC content of 43.26%, showing 98.39% completeness in BUSCO analysis. In total, we predicted 39,934 protein-coding genes, 88.79% of which could be functionally annotated. This genome assembly provides a valuable resource for unraveling Z. latifolia’s domestication process, and advances our understanding of the evolutionary history and agricultural potential of Z. latifolia.

Measurement and optimization paths of the multidimensional development levels of counties in the Yellow River Basin: based on the sustainable livelihoods framework

The Yellow River Basin (YRB) faces intense man-land conflicts. However, existing studies rarely focus on the comprehensive and multidimensional development levels in the YRB, and there is a lack of refined county-level studies, making it difficult to fully support the implementation of ecological protection and high-quality development strategy in the YRB. Under the Sustainable Livelihoods Framework, the spatial distribution, differences, and correlation characteristics of the multidimensional development levels of counties in the YRB are disclosed. This is achieved by comprehensively utilizing geospatial, socio-economic, and other multi-source data in combination with methods such as the entropy weight method, the Theil index, and spatial analysis. Optimal development paths are proposed with a focus on the development types of counties. The findings are as follows: (1) Counties in the YRB have a low overall multidimensional development level, presenting a spatial distribution pattern of “high in the east and low in the west” overall. In terms of each dimension, the average value ranking of lower reach > middle reach > upper reach is observed in each dimension; the exception is the financial dimension (with the ranking of middle reach > lower reach > upper reach). (2) Differences between counties in the development indices vary across different dimensions. The differences in the multidimensional development indices and in the development indices of each dimension (except for the natural dimension) are mainly attributable to differences between counties within each reach. Differences between reaches are non-significant. (3) The multidimensional development levels of counties in the YRB and their development levels in each dimension show strong spatial correlation. And significant counties are mainly identified as LL-type (clusters of low value areas) and HH-type (clusters of high value areas). (4) Depending on the measurement results and advantageous factors of the county multidimensional development index, counties are classified into four development types: weak development type, single-dimension-led development type, potential coordinated development type, and multidimensional coordinated development type. Based on this classification, targeted optimal development paths are proposed with a focus on the specific characteristics of different development types. The research findings can provide effective scientific support for ecological protection and high-quality development in the YRB.

The impact of rainfall value on the accuracy of the SCS-CN model: selection of model parameters

ABSTRACT The soil conservation service curve number (SCS-CN) model is a widely utilized tool for estimating runoff and relies on two empirical parameters: the CN and the ratio of initial abstraction to maximum potential retention (λ). The determination of the parameters is via the empirical method or calculations based on actual data. However, few studies address the effect of rainfall on parameter selection, and collecting runoff data for model analysis is challenging. This study, taking the Nemor River Basin in Northeast China as the research region, investigates how the combination of CN and λ impacts the model in different rainfall conditions. Using runoff plots and reanalysis product data, the study reveals that: (1) the calculated methods outperformed the empirical method, increasing the Nash efficiency coefficient from 0.34 to 0.65. (2) A higher λ value (0.2 compared to 0.02) reduces runoff and smoothes the runoff curve, which becomes less obvious with increasing CN. (3) The CN values exhibit a non-monotonic relationship with rainfall, initially decreasing before rising, highlighting the need to adjust the CN based on rainfall. Moreover, the SCS-CN model's performance with reanalysis data approximates that with actual data, confirming the viability of reanalysis datasets in this region.

Microplastic abundance in the surface water of tropical estuarine fronts.

Estuarine fronts are formed due to sharp density discontinuities resulting from the convergence of different water masses. This study, conducted in May and August of 2022 during the southwest monsoon season, focuses on assessing the role of estuarine fronts at Kuala Terengganu estuary in the accumulation of microplastics in surface seawater. The Terengganu River basin area covers approximately 4600 km2 and consists of two main tributaries that drain into the Kuala Terengganu estuary. Microplastic samples were collected from three areas, the plume, front, and shelf, utilizing two methods: manta net (> 350µm) and bucket-water sampling (> 20µm). Results indicate that the estuarine front consistently exhibited higher microplastic concentrations than the plume and shelf regions throughout the study period, with bucket-water sampling contributing significantly to the abundance. Specifically, peak concentrations occurred during the ebb tide at the frontal region in both months, reaching 5761.703 particles m-3 and 12,687.437 particles m-3, respectively. The microplastics, predominantly transparent fibers smaller than 1000µm, mostly showed signs of oxidative and mechanical weathering through SEM-EDS analysis, providing insights into their fate in estuarine surface waters. FTIR spectroscopy revealed polypropylene, polyethylene, and polyamide as the dominant polymers. These findings establish a baseline for microplastic abundance at the estuarine front of the Kuala Terengganu estuary and may inform future strategies for mitigating and recovering microplastic contamination in aquatic environments.

Enhanced Flood Monitoring in the Pearl River Basin via GAIN-Reconstructed GRACE Terrestrial Water Storage Anomalies

Floods are a significant and pervasive threat globally, exacerbated by climate change and increasing extreme weather events. The Gravity Recovery and Climate Experiment (GRACE) and its follow-on mission (GRACE-FO) provide crucial insights into terrestrial water storage anomalies (TWSA), which are vital for understanding flood dynamics. However, the observational gap between these missions presents challenges for flood monitoring, affecting the estimation of long-term trends and limiting the analysis of interannual variability, thereby impacting overall analysis accuracy. Reconstructing the missing data between GRACE and GRACE-FO is essential for systematically understanding the spatiotemporal distribution characteristics and driving mechanisms of interannual changes in regional water reserves. In this study, the Generative Adversarial Imputation Network (GAIN) is applied to improve the monitoring capability for flood events in the Pearl River Basin (PRB). First, the GRACE/GRACE-FO TWSA data gap is imputed with GAIN and compared with long short-term memory (LSTM) and k-Nearest Neighbors (KNN) methods. Using the reconstructed data, we develop the Flood Potential Index (FPI) by integrating GRACE-based TWSA with precipitation data and analyze key characteristics of FPI variability against actual flood events. The results indicate that GAIN effectively predicts the GRACE/GRACE-FO TWSA gap, with an average improvement of approximately 50.94% over LSTM and 68.27% over KNN. The reconstructed FPI proves effective in monitoring flood events in the PRB, validating the reliability of the reconstructed TWSA. Additionally, the FPI achieves a predictive accuracy of 79.7% for real flood events, indicating that short-term flood characteristics are better captured using TWSA. This study demonstrates the effectiveness of GAIN in enhancing data continuity, providing a reliable framework for large-scale flood risk assessment and offering valuable insights for flood management in vulnerable regions.

Influence of Anthropogenic and Climatic Factors on the Dynamics of Nitrogen and Phosphorus in an Urbanized River Basin

The management of and reduction in ammonia nitrogen (NH3-N) and total phosphorus (TP) in the water environment are crucial for protecting water quality amid rapid urbanization and population growth in highly industrialized regions. Specifically, in the Xiangjiang River Basin, the development of the Chang–Zhu–Tan urban agglomeration resulted in the deterioration of river water quality in the past, where ammonia nitrogen (NH3-N) and total phosphorus (TP) were the dominant pollutants. This study aims to assess the influence of anthropogenic and climatic factors on the dynamics of nitrogen and phosphorus in an urbanized river basin in the middle Xiangjiang River Basin, China, from 2016 to 2020. This study examines NH3-N and TP trends and their influencing factors across six tributaries, as well as how their concentrations have changed in response to urbanization and wastewater treatment management. The results reveal that average NH3-N and TP concentrations decreased from 2016 to 2020 in the urbanized river system. NH3-N and TP concentrations exhibited positive correlations with the proportion of cropland and negative correlations with population number, percentages of urban lands, and forests. In contrast, the influence of precipitation and streamflow on NH3-N and TP concentrations was relatively weak. Consequently, agricultural activity was the primary contributing factor to NH3-N and TP concentrations. Our study also suggests that the government’s newly implemented water protection regulations can effectively control pollutant levels in urbanized river basins.

Contribution of the GRACE Satellite Mission to Mapping Water Mass Variations in River Basins

Abstract. In the context of climate change, there is a need to understand the dynamics and temporal fluctuations of continental water. Such knowledge is essential for the development of more effective and sustainable management strategies for this indispensable resource. The Earth's gravitational field is not constant but varies over time due to factors such as mass redistribution during the hydrological cycle. The GRACE satellite mission (Gravity Recovery and Climate Experiment) provides valuable information about the geodynamic behaviour of our planet by estimating variations in the continental water storage from the temporal changes in the Earth’s gravity field.The aim of this work is to demonstrate the contribution of satellite gravimetry to identify patterns of variation in continental water masses within large river basins. For this purpose, a regional study of the TWS (Total Water Storage) derived from GRACE was carried out, focusing on the spatial and temporal changes detected in the La Plata Basin in South America. The periods with the most extreme variations between 2019 and 2023 were analyzed, and the TWS was compared with satellite precipitation data, to subsequently relate them to ENSO events that occurred in the region. The results show that GRACE detected the significant changes in water storage, highlighting in particular the severe drought that occurred in this basin in 2022.

Spatio-temporal characterization of precipitation in the Middle and Lower Paraguay Basin based on satellite products and weather station data

Abstract. This study presents a temporal analysis aimed at identifying climatic patterns that influence precipitation behavior in the Middle and Lower Paraguay Basin, part of the Paraná River Basin in Paraguayan territory. This research utilizes satellite-based geospatial technologies to analyze the spatial and temporal variability of precipitation in the region. Satellite precipitation images were used for the period 2001–2023, available on NASA's GIOVANNI platform. The results from the classical exploratory statistical analysis allowed for the identification of data distribution, spatial and temporal variability of precipitation in the basin, areas with the highest accumulations, and drought periods, as well as extreme events associated with the El Niño-Southern Oscillation (ENSO) phenomenon, which impacts southern tropical America, including Paraguay. Through the use of remote sensing data and geomatics techniques, this study supports the goals of GEM24, which focus on applying geospatial technologies to address environmental monitoring challenges. The average monthly precipitation series shows a steady trend, with a decrease in recent years. The lowest average was in August 2004 (5.6 mm), and the highest was in December 2015 (345.22 mm). December is the month with the highest average precipitation, while August records the lowest value. The validation between the precipitation data obtained from the Giovanni platform and conventional weather station data, through correlation and linear regression analysis, revealed a strong and statistically significant relationship, indicating that the satellite model is suitable for predicting precipitation, although not perfect. Additionally, the study of temporal anomalies identified prolonged drought periods (2001–2013 and 2020–2022), with intensification in 2020, and periods of intense rainfall (2014–2019), highlighting the 2015 floods. The spatial precipitation anomalies during El Niño (2015) and La Niña (2020), using IMERG and CHIRPS data, allowed for the identification of precipitation spatial patterns. The areas with the highest precipitation were concentrated in the east and south of the country, while drier areas, such as the Paraguayan Chaco in the basin (west), recorded lower precipitation. This study underscores the role of satellite data and geomatics in environmental monitoring, demonstrating how these technologies can enhance our understanding of climatic patterns and extreme weather events. The findings highlight the importance of geospatial data in global environmental change assessments and the monitoring of regional climatic variability, which are central to the objectives discussed in GEM24.

Violence against memory: communicative strategies of Scythian barrow reuse

This article provides a diachronic analysis of barrow reuse during the Bronze Age and Scythian times, focusing on a case study from the right bank of the Molochna river basin (North Azov, Ukraine). It compares the successive chronological phases of barrow-building cultures from the Yamna to the Scythian time regarding their spatial arrangement, patterns of secondary burial inclusions, and burial reopenings. The spatial analysis shows that all barrow clusters appeared in this territory during the Yamna phase. In all subsequent phases, barrows continued to be constructed exclusively within these pre-existing clusters. Various types of burial inclusions and mound modifications were typical for all Bronze Age phases. However, while Scythian burials maintained the reuse of predecessor’s barrows, they seldom made secondary burials in contemporary barrows. Simultaneously, the number and scale of burial destructions significantly increased during the Scythian time. This shows a shift in attitudes towards barrows within distant and living memory and their role in communicating inheritance claims.

Application of an Ensemble Stationary-Based Category-Based Scoring Support Vector Regression to Improve Drought Prediction in the Upper Colorado River Basin

Recent above-normal temperatures, which exacerbated the impacts of precipitation deficits, are recognized as the primary driver of droughts in the Upper Colorado River Basin (UCRB), USA. This research aims to enhance drought prediction models by addressing structural changes in non-stationary temperature time series and minimizing drought misclassification through the ES-CBS-SVR model, which integrates ESSVR and CBS-SVR. The research investigates whether this coupling improves prediction accuracy. Furthermore, the model’s performance will be tested in a region distinct from those originally used to evaluate its generalizability and effectiveness in forecasting drought conditions. We used a change point detection technique to divide the non-stationary time series into stationary subsets. To minimize the chances of drought mis-categorization, category-based scoring was used in ES-CBS-SVR. In this study, we tested and compared the ES-CBS-SVR and SVR models in the Upper Colorado River Basin (UCRB) using data from the Global Land Data Assimilation System (GLDAS), where the periods 1950–2004 and 2005–2014 were used for training and testing, respectively. The results indicated that ES-CBS-SVR outperformed SVR consistently across of the drought indices used in this study in a higher portion of the UCRB. This is mainly attributed to variable hyperparameters (regularization constant and tube size) used in ES-CBS-SVR to deal with structural changes in the data. Overall, our analysis demonstrated that the ES-CBS-SVR can predict drought more accurately than traditional SVR in a warming climate.

Ecological Network Construction Based on Ecosystem Services and Landscape Pattern Indices in the Tabu River Basin

Unsustainable human activities threaten the ecological security of arid and semi-arid watersheds. However, improving the connectivity of ecological networks can enhance ecosystem services and preserve biodiversity in these fragile environments. In this study, we aimed to identify ecological sources of the Tabu River Basin by quantifying five key ecosystem services and using a morphological spatial pattern analysis model. We further optimized resistance surfaces using landscape pattern indices, constructed an ecological network, and provided recommendations for sustainable management. The results obtained were as follows: (1) Ecosystem services in the Tabu River Basin exhibit clear spatial heterogeneity, with significant increases in water yield, food supply, and carbon sequestration over the past two decades. (2) Landscape pattern indices, such as the aggregation index, patch cohesion index, and Shannon’s diversity index, showed declines, indicating heightened landscape fragmentation and reduced connectivity. (3) Over the study period, the number of ecological sources increased from 6 to 17, although the total area of these sources decreased. The number of corridors expanded from 9 to 36, with a total length increase of 362.47 km, whereas pinch points increased from 27 to 40. (4) After optimization, one additional corridor and 24 new pinch points were identified, alongside a marked reduction in resistance in the northern and central-western regions. These results provide a robust scientific basis for optimizing land-use planning and reinforcing ecological security in the Tabu River Basin.

Spatio-temporal patterns and trends of streamflow in water-scarce Mediterranean basins

Abstract. The issue of water scarcity, exacerbated by climate change and demographic increase, has become a growing concern in many regions throughout the world. Understanding hydrological behaviour to promote resilient and sustainable water management is paramount. Hydrological models that integrate natural processes and anthropogenic alterations of the basin's hydrology are a powerful tool to support decision-making. We developed a SWAT+ hydrological model including stakeholder expert knowledge on water management and introducing a novel calibration and validation approach suitable for heterogeneous basins in space and/or time. We also assessed spatio-temporal patterns and trends of streamflow during the first 2 decades of the 21st century in the Catalan River Basin District, in the western Mediterranean, using a wide variety of indicators to fully characterize the hydrological regime. We calibrated and validated the model using data from 50 gauging stations, verifying the usefulness of the new calibration and validation strategy. Co-development with stakeholders and the integration of expert knowledge, most notably on reservoir operations, helped improve model performance. Results revealed a generalized streamflow reduction, as well as increased dominance of streamflow flashiness and zero-flow recurrence. We also observed differences in seasonal trends, with autumn being the most affected season. These results provide insights into how climate change and anthropogenic pressures are going to keep affecting water resources availability in the future, thus raising the need for sustainable management practices in the Catalan River Basin District, as well as other regions vulnerable to water scarcity.

Spatio-Temporal Pattern of the Coupling Relationship between the Regional Exhibition and Manufacturing Industries—Empirical Exploration Based on the Yellow River and Yangtze River Basins

Spatio-Temporal Pattern of the Coupling Relationship between the Regional Exhibition and Manufacturing Industries—Empirical Exploration Based on the Yellow River and Yangtze River Basins

Predicted effect of the grand Ethiopian renaissance dam on the Epilimnion temperature in the high Aswan dam reservoir

AbstractThe Nile River is a crucial geopolitical water stream. The construction of the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile poses significant challenges for downstream countries, including Egypt. The GERD will be the largest hydroelectric power plant in Africa and the seventh in the world. This led many researchers to investigate the impacts of the dam construction on water quantity, agriculture, power generation, and the environment. This study aims to investigate some of the environmental impacts of the operation of the GERD on the High Aswan Dam (HAD) reservoir. Water level fluctuations due to the operation of the GERD will directly affect the thermodynamics of the HAD reservoir. As a result, the vertical distribution of heat will be altered assuming the incoming solar radiation will remain the same. Studies indicate that the water level in the HAD reservoir will decline by 10–27 m, due to the filling of the reservoir upstream of the GERD over the next few years. To quantify the change in temperature, the heat content for the reservoir is calculated pre‐ and post‐dam operation. Moreover, a one‐dimensional simulation model, DYnamic REservoir Simulation Model (DYRESM), was used to simulate the change in thermal stratification of the HAD reservoir pre‐ and post‐GERD operation. Results showed that the epilimnion temperature is expected to increase during summer from an average of 31.9°C pre the GERD operation to 33.7°C post the GERD operation. Consequently, this is expected to affect the ecosystem in the reservoir. The findings of this study highlight the significant environmental impacts of the GERD on HAD reservoir. To mitigate these impacts and ensure the sustainable management of water resources in the Nile River basin, it is imperative to implement comprehensive policies and strategies.

The Coordination of Water Resources and Economic Development in a Water-Scarce Area: An Ecosystem Service Perspective

In water-scarce areas, there is a complex interrelationship between water resources and economic development. This paper studies the relationship between water resources and economic development from an ecosystem services perspective. This paper selected the value of river ecosystem service functions and the comprehensive index of economic development in the Yellow River Basin (YRB) from 2007 to 2018 as the research object, tested the synergy of ecosystem service functions in the basin, and introduced a coupling coordination model to evaluate the synergy of developmental factors. The research results showed that (1) the overall river ecosystem service value in YRB was on the rise, and its distribution was characterized by a high value in the lower reaches and a gradual decrease from the middle reaches to the upper reaches; (2) the synergy of river ecosystem service functions in YRB was mainly reflected in the supply and regulation functions, and the synergy of cultural functions should be improved; (3) the overall coupling and coordination degree showed an upward trend. However, judging from the characteristics of coupled and coordinated degrees, backward ecological development is a long-term problem. This article will help to put forward countermeasures and suggestions for the coordinated development of the river ecosystem service value and regional economy in YRB.