Watercourses in agricultural areas often receive diffuse pesticide inputs through drift, runoff, infiltration, and erosion. We assessed the qualitative and quantitative response of the zooplankton community to pesticide exposure in the Estacas stream basin, Argentina, over two years at seven sites. Surface water and zooplankton were sampled every two months, and 125 pesticides were screened and classified by detection frequency. A total of 24 pesticides and the AMPA metabolite were detected. Dominant pesticides included atrazine, glyphosate, and AMPA in the first year, and metolachlor and S-metolachlor in the second. Sixty-three zooplankton taxa were identified, primarily rotifers (65%) and cladocerans (35%), with peak richness at one site during spring of the second year. Copepods were present but less frequent, with Cyclopoida being the most common. Microzooplankton dominated across sites, with higher densities in the first year. Canonical Correlation Analysis showed that glyphosate and atrazine were probably associated with microzooplankton abundance in the first year, while metolachlor and S-metolachlor were associated with copepod and rotifer populations in the second. This study represents the first report on zooplankton community responses to pesticide gradients in this basin, providing crucial information on this bioindicator's sensitivity to land use changes and pesticide application timing. These insights can help the development of environmentally sustainable agricultural practices.

Influence of abiotic variables on the diversity and co-occurrence of fish assemblages in streams of the paranapanema basin, Brazil

Multi-compartment assessment of thallium in a typical agricultural watershed in China: Occurrence, criteria derivation, and risk characterization.

The Whole Story of the Shanhe Weirs Water Case in the Baishaxi Stream Basin of Jinhua in the Late Qing Dynasty

This study develops and calibrates a SWAT+ hydrological model for the Arıt Stream Basin in Bartın Province, Türkiye. The basin (approximately 187 km² based on watershed delineation) was modeled using the QSWAT+ interface in QGIS, and an automatic calibration was performed with the SWAT+ Toolbox (v3.1.0). The model was driven by a 25 m DEM, 2018 CORINE land cover, FAO soil map, daily meteorological data (2010–2024), and monthly streamflow observations (2013–2024) at the Darıören gauge (basin outlet). After a 3-year warm-up (2010–2012), the model was run for 2013–2024 on a daily time step; calibration (2013–2018) and validation (2019–2024) were evaluated at monthly flows. Key performance metrics—Nash–Sutcliffe Efficiency (NSE), coefficient of determination (R²), percent bias (PBIAS), root mean square error (RMSE), and RMSE-observations standard deviation ratio (RSR)—indicate that the model reproduces the basin’s streamflow dynamics within acceptable ranges. Monthly calibration results yielded NSE ≈ 0.56 and PBIAS ≈ +6 %, and validation NSE ≈ 0.51 and PBIAS ≈ +9 %, with RSR ≈ 0.66–0.70 (satisfactory per literature criteria). The calibrated model successfully captures seasonal flow patterns and baseflow contributions, providing a reliable tool for scenario analyses and water resources management in the region. These results mark one of the first comprehensive SWAT+ applications in the Bartın region, demonstrating the model’s utility and laying a foundation for future climate change, land-use, water quality, and water–energy nexus studies. Based on 2010–2024 MGM monthly climatology, the basin’s climate is humid temperate with no dry season (Cfb): the warmest-month mean is 21.7 °C (August,

Accurate flood simulation is essential because climate change increases the risk of flash floods resulting from extreme rainfall. Traditional grid-based physical models exhibit spatiotemporal uncertainties due to parameter estimation difficulties and structural simplifications. This study developed a two-phase Physics-Informed Machine Learning (PIML) hybrid grid-based flood model by sequentially combining a physical model with machine learning to overcome these limitations. The methodology consisted of temporal (Phase 1) and spatial (Phase 2) corrections. In Phase 1, a PIML model, trained on flow observations (target) using discharges and lagged rainfall from a lumped model (inputs), estimated a temporal correction ratio to correct temporal errors. In Phase 2, a spatial machine learning (ML) model was trained on flood risk maps (target) using flood depth and topographical features (e.g., digital elevation model and slope data) of a distributed model as inputs. In the hybrid simulation, the temporal correction ratio (Phase 1) was applied to the grid cell flow of the distributed model. The resulting flood depth was then fed into the spatial ML model (Phase 2) to produce the final, sequentially corrected flood depth, thus reducing spatiotemporal uncertainty. When applied to the Gyeongan stream basin, Phase 1 significantly enhanced hydrograph accuracy compared with the physical model. The full hybrid model, including Phase 2, corrected the inundation estimation errors of the physical model in scenario analysis, improving spatial accuracy and aligning results with official frequency-based Flood Risk Maps. The proposed two-phase PIML integrates the interpretive strengths of physical models with the nonlinear pattern recognition of ML, thereby offering an alternative for enhancing the practical utility of grid-based flood simulations.

This paper aims to examine the latest excavation results, clarify the characteristics of the structure, burial customs, and excavated artifacts, and ultimately define the nature of the groups that constructed Stone-Mound Tombs distributed in the Inland Central Region of the Korean Peninsula from the Proto-Three Kingdoms Period to the Hanseong Period of Baekje. By taking into account the tomb-building groups in the surrounding ditch-enclosed pit-tomb and mound-tomb territories, this study presents the social characteristics of the Stone-Mound Tomb groups and describes their developmental process after the 4th century. Based on the excavation results from sites like Gonjiam-ri in Gwangju and Aura-ji in Jeongseon, the Stone-Mound Tombs in the Inland Central Region are characterized by the Conjoined Multiple Burial-Pit Type, where multiple main burial chambers are sequentially connected. In terms of burial customs, no wooden coffins or chambers were used, and multiple secondary burials and multiple-person burials are confirmed. The combination of secondary and multiple-person burials observed in these tombs is comparable to various archaeological data, including cremated human remains from the Jungdo Cultural Sphere, suggesting a connection to indigenous, local burial traditions. Furthermore, prolonged communal ritual activities, such as the deposition of pottery fragments and animal sacrifices, persisted in both the chambers and the stone mounds. An examination of the excavated artifacts reveals that while the types of pottery vary slightly across different river basins, bronze bells and bronze rings are commonly found and are considered symbolic artifacts of the Stone-Mound Tomb construction groups. Regarding bead artifacts, a variation in quantity is observed across river basins, with the Imjin River and Gyeongan Stream basins being particularly distinctive for the large quantity of finds. The Stone-Mound Tombs in the Inland Central Region were actively constructed during the 3rd century, a period coinciding with the emergence of numerous regional polities in the central region, with the construction limit set around the mid-4th century. Slight regional differences are confirmed, which appear to be tied to the political context of the time. By estimating the potential number of households interred in the Stone-Mound Tombs at the Gwangju Gonjiam-ri site, it is presumed that each chamber was responsible for approximately 1 to 3 members of the settlement. Considering the application of multipleperson burial, the Stone-Mound Tomb is interpreted as a communal cemetery intended for the entire settlement membership, rather than a tomb reserved for a specific ruling class. The hierarchical differences between the chambers are minimal in terms of size and excavated artifacts, a contrast to the elite tombs of the Mahan sphere during the Proto-Three Kingdoms Period. The Stone-Mound Tombs demonstrate a low level of social stratification while presupposing a high level of communal identity centered on the generational complex and the entire settlement. Meanwhile, the Gyeongan Stream basin is a transitional zone where Stone-Mound Tombs intersect with ditch-enclosed pit-tombs. The appearance of a modified Stone- Mound Tomb at the Myeongpyeong-dong site in Yongin during the 4th century is noteworthy. The modified Stone-Mound tomb observed at the Myeongpyeong-dong site can be interpreted as closely linked to the socio-cultural changes experienced by the local society following the expansion of Baekje's central authority and the vigorous influx of population during the Hanseong Period.

Climate change poses substantial threat to water quality in Jordan. It may lead to saline water intrusion into freshwater reserves, increased water pollution, and scarcity of freshwater. This study aims to investigate the impact of climate change on water quality in Zarqa Stream Basin, Jordan. One hundred and twenty water samples were collected from Zarqa Stream, and were distributed equally between the three study locations, namely, Jerash, Zarqa, and King Talal Dam. Laboratory analyses and tests, that is; basic water components, were performed on the water samples according to the standards approved in the specialized laboratories of the Ministry of Health, Jordan, and the Ministry of Water and Irrigation, Jordan. The study results uncovered variations in concentrations of chemical parameters of water quality among the three studied sites (Zarqa, Jerash, and King Talal Dam), suggesting diverse effects due to environmental pollution and surrounding conditions. Water quality varies in Zarqa Stream Basin from a location to another, and despite the fact that some indicators meet international standards, the water has high level of turbidity, high concentrations of dissolved substances, and a high electrical conductivity, making it unsuitable for human drinking. The study highlights organic pollution and changes in certain chemical elements. This necessitates adoption and implementation of effective measures to improve and protect the water quality in this basin. Non-essential water components have been significantly affected by climate change, with some surpassing safe limits. This calls for rapid treatment and continued monitoring to avoid negative consequences. These changes should be considered in water quality assessments. Additionally, awareness of the impact of climate change on water quality should be raised and the local communities should be encouraged to take action to preserve water resources and protect the water quality from deterioration

This research aims to utilize GIS techniques to identify the morphometric characteristics of the Wadi Al-Kumel basin in Iraq, encompassing its spatial, morphological, topographical, and drainage characteristics, as well as the drainage patterns of the basin, to establish a digital morphometric information base for the basin. The research is based on the analysis of Landsat 8 (OLI) satellite images, digital elevation models (DEM), and field studies, utilizing ArcGIS Desktop 10.8 to prepare maps for drainage networks, determine waterway ranks, and calculate morphometric parameters. The data of the meteorological stations are relied upon to identify the type of climate of the region. The analytical and quantitative approaches are also relied upon to analyze and measure the morphometric variables, producing a map of the river network and classifying its ranks according to the Strehler method, and then analyzing the natural characteristics affecting the basin, including geological formations, topographic characteristics, climate, soil, and natural vegetation. The Wadi Al-Kumel basin is located in the northern and northeastern parts of Iraq within the undulating and high mountainous region between Nineveh and Dohuk Governorates. The total basin area reaches (926.29) km2 and a length of approximately (70) km. The number of river levels reaches six, varying in streams number and lengths according to their levels. The total number of basin streams reaches 3242 streams. This variation is due to the processes of their formation and origin, in addition to the variation in the environmental characteristics that compose them. There is also a variation in the topographic characteristics of the different parts of the basin due to the difference in the topography of the region.

This study compares the Analytic Hierarchy Process (AHP) and Frequency Ratio (FR) methods for landslide susceptibility mapping in the Kömür Stream Basin, Kemah-Erzincan. The performance of the models was comprehensively evaluated using metrics including the Receiver Operating Characteristic (ROC) curve, F1-Score, and overlap rate analysis. The results revealed that the statistics-based FR model Area Under the Curve (AUC) = 0.884, F1-Score = 0.87 significantly outperformed the expert opinion-based AHP model (AUC = 0.699, F1-Score = 0.68) for across all metrics. In the overlap rate analysis, which demonstrates the practical validity of the models, 92.7% of the existing landslide areas fell within the 'High' and 'Very High' susceptibility classes on the FR map compared to 73.7% on the AHP map. These findings prove that the FR method is a reliable and precise tool for identifying high-risk areas and for land-use planning in the region.

Evaluation of Potential Geoheritage Elements with LBWA-based ADAM Techniques: A Case Study in the Aksu Stream Basin (Giresun, Türkiye)

In a global context where the degradation of water resources is increasing, it is important to integrate the characteristics of the natural environment with those of the socioeconomic environment to prepare environmental diagnoses at the basin level. This study was carried out in the Chapaleofú stream basin, Tandil district, Buenos Aires, Argentina. Its objective was to diagnose the environmental situation of the water resources of the Chapaleofú stream basin by integrating aspects of the physical environment with those of the socioeconomic environment. For this integration, the combination method was used, which subsidiarily integrates a (qualitative) methodology with quantitative methodologies to reinforce the latter. Some of the results (the population uses dowsing to select the location of the boreholes, perceives on the surface the modification of groundwater along its path, detects changes in the stream bed that worsen flooding, rural producers negatively value the use of agrochemicals but recognize their need) show a coexistence of knowledge of water resources from their daily use with decisions and difficulties typical of the lack of specific technical assistance and practices established by habit. The integration of methodologies allowed us to detect this synchronism that had not been identified using only hydrology studies. Keywords: Environment, Hydrogeology, Interview, Land use, Herbicide.

BackgroundUnderstanding the movement of organisms is critical for species conservation in the context of changing landscapes and climate. As climatic extremes impact the United States Great Basin, quantifying the movements of native fishes like Lahontan cutthroat trout (Oncorhynchus clarkii henshawi) is vital for facilitating their persistence. These climatic extremes are projected to alter flow regimes, specifically, reducing hydrologic connectivity needed to maintain populations. By studying fish movement patterns during streamflow recession and baseflow conditions, we can identify the factors responsible for movement and habitat selection to better manage these factors in a changing world.MethodsWe radio tagged 57 stream-resident Lahontan cutthroat trout from early summer to fall in 2021 and 2022 in the Summit Lake watershed (NV, USA). The location of each fish was associated with local hydraulic, physical habitat, invertebrate drift concentration, and water quality data to assess which factors impact habitat selection, abandonment, and overall movement. Linear mixed effects models were used to assess which factors were associated with trout movement. Density estimates from electrofishing were used as a proxy to assess habitat selection using multiple linear regression modeling.ResultsStream-resident trout displayed little movement during streamflow recession and baseflow conditions, with median daily movements of 0.3 m/day and a median home range of 10.2 m; these results suggest even less movement than those reported in previous studies. Declines in riffle crest thalweg (RCT) depth were the primary factor associated with increases in distance traveled, yet there were only four observed movements below RCT depths of 5 cm and no observations below 4 cm. Woody debris, mean maximum stream depth, and availability of mid-channel pool habitat were the strongest predictors of habitat selection.ConclusionsThe findings from this study suggest that stream-resident trout movement occurs when absolutely necessary, such as escaping drying reaches or avoiding risk of predation in shallow water. We suggest that watershed managers implement low-flow hydrologic monitoring to identify vulnerable stream reaches, with an emphasis on preserving streamflow connectivity for stream-rearing salmonids. Additionally, this emphasizes the importance of tracking movements for species of interest as a strategy to identify factors potentially reducing population fitness.

The Mayan cichlid (Mayaheros urophthalmus) is an endemic species that supports an artisanal fishery exploited year-round. It has tolerance for various environmental conditions, including wide ranges of salinity and temperature. These conditions favor the development of aquaculture; however, this potential has not been thoroughly explored. To evaluate the reproductive potential of organisms from different locations as well as the effect of intraspecific crossbreeding from locations with different environmental conditions, such as low temperature (Nauchinapa Stream Basin, ANB), brackish water (Usumacinta River Lower Basin, ULB), and freshwater (Grijalva River Lower Basin, GLB; and Usumacinta River Mid-Basin, UMB). A randomized one-factor design was used to perform the diallelic crosses with combinations between all locations. ANB females were the most productive, accumulating 39 spawns, producing 104 664 hatchlings, more than double that of the GLB females, with 18 spawns and 49 200 hatchlings produced. UMB females had 15 spawnings with a total of 37 404 hatchlings, and ULB females had only 11 spawnings with 25 509 hatchlings. ANB females were more productive than females from other locations, with a median of 21.65 hatchlings per gram of female. The species present a high reproductive potential; besides being able to spawn multiple occasions in a season, the fry per spawning is higher than in tilapia. The results are consistent with the hypothesis that the reproductive performance of different populations of the same species depends on differences in their life cycle and can be enhanced or inhibited by the conditions under which production occurs.

Songhua River Basin, northeast China, has seen significant changes due to climate change and human activities from 1990 to 2000, when forests were largely reclaimed and agricultural land was taken up to change the terrestrial water cycle drastically. This paper investigates hydrological changes in three basins: the main stream basin of the Songhua River, the Second Songhua River Basin, and the Nenjiang River Basin. Machine learning and signal processing techniques have been applied to reconstruct historical river records with high accuracy, achieving determination coefficients exceeding 0.97. The physically based WEP model effectively simulates both natural hydrological patterns and human-induced hydrological processes in the northern Nenjiang region. Climate projections indicate clear temperature increases across all scenarios. The most significant warming is observed under the SSP5-8.5 scenario, where runoff increases by 8.52% to 12.02%t, with precipitation driving 62% to 78% of the changes. Summer runoff shows the most significant increase, while autumn runoff decreases, particularly in the Nenjiang Basin, where permafrost loss alters spring melt patterns. This change elevates flood risk in summer, with the rate of increase strongly dependent on the scenario. Water resources show strong scenario dependence, with the average growth rate of SSP5-8.5 being 4 times that of SSP1-2.6. A critical threshold is reached at a 2.5 °C increase in temperature, triggering system instability. These results emphasize the need for adaptation to spatial differences to address emerging water security challenges in rapidly changing northern regions, including nonlinear hydroclimatic responses, infrastructure resilience to flow changes, and cross-basin coordination.

Redefining and delineating pristine conditions: A methodological framework with an application to a minimally impacted Mediterranean stream basin

A total of 600 polychaete species are known in Argentina, mostly marine. Freshwater representatives are poorly documented, with only 22 species reported for the Neotropical region. This study presents the first record of Stratiodrilus brevicirrus (Histriobdellidae, Polychaeta) in Entre Ríos Province, Argentina, extending its known distribution from southern Brazil into the Pampean region. Specimens were collected during seasonal macroinvertebrate surveys in 2021 across streams of the Lower Uruguay River Basin. A total of 42 individuals were found in rocky and vegetated substrates and identified using updated taxonomic keys. Voucher specimens were deposited in the Museo Ciencias Naturales de La Plata. This is the second record of the genus Stratiodrilus in the country and the first for this species. Although collected free-living, known host families (Aeglidae and Trichodactylidae) were also present. This record highlights the importance of surveying underexplored freshwater systems, provides new data for national species checklists, and supports future conservation planning in fluvial environments.

In this study, the effects of flood, drought and water pollution on the main agricultural products in Bilecik Province were examined. In the study, Arap and Delikbağ streams in Gölpazarı; Gümüşdere in Pazaryeri; Çöte stream basins in Yenipazar were used. The characteristics of the watershed (such as area, length, slope, curve number) and climate data (such as precipitation, temperature and evapotranspiration) were prepared and were used in the WinTR-55 and were used in DrinC model. As a result, the R2 (Determination coefficient) value between the result of RDI drought index and hop yield reached the highest value with a value of 0.50 in Pazaryeri among the compared districts. The R2 value between the RDI drought index result and wheat yield reached the highest value with a value of 0.80 in Söğüt among the compared districts. Besides, a significant decrease was observed in drought index values in Bilecik in 2017. The years when drought was most apparent in Bozüyük were 2006 and 2007. In Pazaryeri, 2007 year was that the effect of drought was felt most intensely. The peak flow values of the 100-year return period were compared in the watershed using the WinTR-55 model. Gölpazarı-Arap Stream was the area with the highest flood risk with 66.59 m³/s. This was followed by Gölpazarı-Gümüşdere with 47.06 m³/s, Gölpazarı-Delikbağ Stream with 47.00 m³/s and Yenipazar-Çöte with 26.27 m³/s, respectively.

Resumen El vínculo entre arte y naturaleza es central para construir resiliencia en el marco de la crisis climática. Dentro del Proyecto de Investigación: “Suelo vacante, riesgo hídrico y paisaje. Proceso de urbanización reciente en el sudeste del Gran La Plata y estrategias para la planificación del crecimiento urbano desde las cuencas hidrográficas” se desarrollaron distintas acciones artísticas, con el fin de visibilizar las interacciones entre naturaleza y urbanización que se dan en una nueva periferia urbana de la ciudad de La Plata (Argentina). El objetivo de este trabajo es exponer las obras desarrolladas para fomentar la experiencia persona-naturaleza, en las que la escala es la humana y la conexión con el medio es parte de ellas.

River basin hydrology is meaningfully influenced by morphometric characteristics such as shape, size, and relief. These features play a serious role in shaping hydrological processes, including runoff, infiltration, and erosion. This study examines the morphometric parameters of the Gelda watershed in the Tana sub-basin of Ethiopia to assess their impact on hydrology. The research utilized ASTER Digital Elevation Model (DEM) data with a resolution of 12.5 m and ArcGIS 10.5 for spatial analysis. Key morphometric parameters were extracted from the DEM, including stream order classifications, bifurcation ratio, and drainage density. Statistical methods were applied to evaluate the relationships between these parameters and various hydrological characteristics. The findings indicate that the Gelda watershed is classified as a 5th-order stream basin, with a mean bifurcation ratio of 1.76, suggesting moderate branching in the stream network. The drainage density was measured at 1.65 km/km2, indicating a high potential for surface runoff and low permeability. This condition increases the basin's vulnerability to soil erosion and limits its water retention capacity. These situations are crucial for effective water resource management, soil conservation, and erosion control strategies in the region and other similar river basins worldwide. The study recommends implementing targeted soil conservation practices and effective water management strategies to mitigate erosion risks and enhance water retention. Future research should integrate morphometric analysis with hydrological modeling to better predict the impacts of land use changes on basin hydrology.