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Highlights some practical applications for art and river education to encourage teachers to create such programs. Describes the "Art and River" Program that consists of four half-day lessons at a river park. Discusses the importance of rivers and Native American beliefs about the land and rivers. Lists additional resources. (CMK)

Explores the Columbia River Basin, its ecosystems, and challenges faced by natural resource managers. By studying the basin's complexity, students can learn about common scientific concepts such as the power of water and effects of rain shadows. Students can also explore social-scientific issues such as conflicts between protecting salmon runs and providing electricity through hydropower. Includes classroom activity guide and poster. (PVD)

An assessment of the water quality of the Colorado River in the Grand Canyon was made, using the following parameters: dissolved oxygen, water temperature, hydrogen ion concentration, total dissolved solids, turbidity, and ammonium/nitrogen levels. These parameters were used to provide some clue as to the "wellness" and stability of the aquatic ecosystem. (KR)

Describes Ohio's Scenic Rivers Monitoring Program that uses benthic macroinvertebrates, such as the stonefly, mayfly, and water penny beetle larva, as key indicators of water quality and stream health. Presents a three-category scheme for invertebrates based upon their tolerance to pollution. Students can collect samples of these organisms, calculate their numbers, and estimate the health of a stream. (PR)

Describes a summer program project designed and conducted by a mixed-age group of elementary children. Students collected data to determine whether a local stream was polluted, and interpretations of the data varied. An informational video about the project and the creek was produced. (PVD)

Reviews two documentaries produced by the U.S. government: "The Plow That Broke the Plains" (1936) and "The River" (1937). The first examines soil erosion in the Great Plains; the second considers Mississippi River usage. Narrates storylines and explains initial film criticism. Highlights the films' effectiveness for teaching about the New Deal and roots of environmentalism. (CH)

Biodiversity is confronted globally by multiple stressors. Environmental policies must regulate these stressors to achieve targets, but how should that be done when the outcomes of limits on one stressor are contingent on other stressors, about which there is imperfect knowledge? Deriving regulatory frameworks that incorporate these contingencies is an emerging challenge at the science–policy interface. To be fit for implementation, these frameworks need to facilitate the inherently sociopolitical process of policy implementation and account transparently for uncertainty, such that practitioners and other stakeholders can more realistically anticipate the range of potential outcomes to policy. We developed an approach to quantify stressor limits that explicitly accounts for multistressor contingencies. Using an invertebrate data set collected over 30 years throughout New Zealand, we combined ecological and ecotoxicological models to predict biodiversity loss as a function of one stressor, treating multistressor contingencies as a form of uncertainty about the outcomes of limits on that stressor. We transparently accounted for that uncertainty by presenting regulatory limits as bands bounded between optimistic and pessimistic views that practitioners may have about the local context within which limits are applied. In addition to transparently accounting for uncertainties, our framework also leaves room for practitioners to build stakeholder consensus when refining limits to suit different local contexts. A criticism of this open, transparent approach is that it creates too much scope for choosing limits that are lenient on polluters, paralyzing on‐the‐ground management of multiple stressors, but we demonstrate that this is not necessarily the case. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As human-caused climate changes accelerate, California will experience hydrologic and temperature conditions different than any encountered in recorded history. How will these changes affect the state's freshwater ecosystems? Rivers, lakes, and wetlands are managed as a water resource, but they also support a complex web of life, ranging from bacteria, fungi, and algae to macrophytes, woody plants, invertebrates, fish, amphibians, reptiles, birds, and mammals. In much of the state, native freshwater organisms already struggle to survive massive water diversions and dams, deteriorating water quality, extensive land cover modification for agriculture and urban development, and invasions of exotic species. In the face of climate change, we need to expand efforts to recover degraded ecosystems and to protect the resilience, health, and viability of existing ecosystems. For this, more process-based understanding of river, lake, and wetlands ecosystems is needed to forecast how systems will respond to future climate change and to our interventions. This will require 1) expanding our ability to model mechanistically how freshwater biota and ecosystems respond to environmental change; 2) hypothesis-driven monitoring and field studies; 3) education and training to build research, practitioner, stewardship, and policy capabilities; and 4) developing tools and policies for building resilient ecosystems. A goals-driven, hypothesis-informed collaboration among tribes, state (and federal) agencies, nongovernmental organizations, academicians, and consultants is needed to accomplish these goals and to advance the skills and knowledge of the future workforce of practitioners, regulators, and researchers who must live with the climate changes that are already upon us and will intensify. [ABSTRACT FROM AUTHOR]

The Kashechewan First Nation (KFN) community is located on a floodplain of the north branch of the Albany River, on the west coast of James Bay. Each spring, the community faces the uncertain prospect of evacuation due to ice-jam flooding, the most severe of which occurred in 2006. A study was conducted to develop long-term options for reducing the flood risk to the community, which included dams, dykes, pier and weir type ice-control structures, and conveyance channels. This paper presents a numerical model study on the Albany River in Ontario, Canada to develop ice control as a potential means for mitigating ice-jam flooding at the KFN community using the two-dimensional ice dynamics model DynaRICE. A method was developed to simulate pier type ice-control structures within the model such that the physical channel conditions, flow conditions, and combinations of ice control could be evaluated. The model allowed detailed simulation of ice retention, resulting inundation, and the forces on the individual piers. To optimize the design of the piers, including pier spacing, height, and size, various combinations of ice, flow, and pier conditions were simulated. Numerical modeling facilitated a comparative examination of flood risk reduction to the community from the various ice control options. [ABSTRACT FROM AUTHOR]

The contribution of citizen scientists to environmental monitoring is notably increasing significantly. Governments worldwide establish Water Users Associations (WUAs) as a good practice model to implement Integrated Water Resource Management (IWRM) at local levels. These associations target different stakeholders depending on the expected outcome. However, their effectiveness, especially in East Africa, can only be determined case by case. In Kenya, Water Resources Users Associations are registered, voluntary community groups whose members are water users and land owners. Similarly, in Uganda, community-based initiatives exist, especially along degraded rivers, involving cooperation between local communities and regional water authorities. On the contrary, it has been reported that in Tanzania, many community initiatives created become non-functional within 2-3 years of induction. In general, the main responsibility of Water Users Associations or its equivalent is to manage and conserve water resources for sustainable uses. In most cases, water quality monitoring by communities through citizen science is limited to the visual appearance of water in the river channel. While this can indicate the water's esthetic value, it is insufficient for assessing the ecological status of rivers, which is influenced by a variety of physical, chemical, biological, and socioeconomic factors. The use of bioindicators has been advocated as a feasible method for community-based water quality river monitoring. Therefore, this review explores the commonly used bio-indicators and bio-assessment tools for river health assessment and their complexities when using a biomonitoring community-based approach through citizen science. Tolerance and intolerance macroinvertebrate and fish metric protocols that utilize identification keys have been recommended. These protocols are designed to be user-friendly and require minimal taxonomic expertise, making them easy for community volunteers to use with minimal basic training. The sustainability of these citizen science initiatives relies on the motivation of volunteers, the frequency of monitoring activities, and collaboration with researchers and government agencies. These initiatives not only facilitate environmental monitoring but also foster community engagement and awareness regarding the ecological status of rivers, thereby addressing knowledge and data gaps necessary for effective policy-making. This approach provides a practical model for environmental stewardship and participatory resource management in East Africa. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Hazards & Environment (JNHE) / Doğal Afetler ve Çevre Dergisi (DACD) is the property of Artvin Coruh University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nearly ninety percent of New Mexico’s rivers and streams potentially have been removed from federal protection under the Clean Water Act following the United States Supreme Court’s decision in Sackett v. EPA to substantially reduce what qualify as “waters of the United States.” Before this decision, many ephemeral streams, tributaries, and wetlands were protected by the Environmental Protection Agency. Permits are essential to protect not only the environment but landowners as well. The New Mexico Environment Department is in the process of developing its own surface water discharge permitting program, as the EPA’s jurisdiction contracted commensurately with the Supreme Court’s new definition of “waters of the United States.” The New Mexico Environment Department and water conservationists worry that without a permitting process, many bodies of water in New Mexico and the United States would be left unprotected, allowing unregulated discharge of harmful pollutants into waters on which the public relies for drinking water, agriculture, recreation, and ecological stability. But is requiring a permit enough to protect the waters of New Mexico? How would obtaining a permit through the state protect waters in New Mexico from those who, either intentionally or unintentionally, discharge pollutants into waters outside of New Mexico that flow into the state? Does the interpretation of “waters of the United States” in Sackett only apply to wetlands? This Note addresses the local problems created by the Sackett decision and offers possible solutions to the lack of protection for states like New Mexico with dry and arid climates. It proposes that it is not enough for the New Mexico Environment Department to create its own permitting process—to truly protect our most precious resource, Congress needs to correct the Court’s mistake and enact an improved definition of “waters of the United States” in the Clean Water Act itself. Congress cannot continue to ignore the reoccurring problem of the Court’s intrusion into environmental regulation. Leaving the interpretation of the Clean Water Act to the United States Supreme Court has proven to be a critical error. The time to act was decades ago, and the consequences of Congress’s inaction are at New Mexico’s doorstep. [ABSTRACT FROM AUTHOR]

Remote sensing can be an effective tool for mapping river bathymetry, but the need for direct measurements to calibrate image‐derived depth estimates impedes broader application of this approach. One way to circumvent the need for field campaigns dedicated to calibration is to capitalize upon existing data. In this study, we introduce a framework for Bathymetric Mapping using Gage Records and Image Databases (BaMGRID). This workflow involves retrieving depth measurements made during gaging station site visits, downloading archived multispectral images, and then combining these two data sets to establish a relationship between depth and reflectance. We developed a processing chain that involves using application programming interfaces to obtain both depth measurements made during site visits and images centered on the gage and then linking depth to reflectance via an optimal band ratio analysis (OBRA) algorithm modified for small sample sizes. Applying this workflow to selected gages within two river basins indicated that depth retrieval from multispectral satellite images could be highly accurate, but with variable results from one image to the next at a given site. High resolution aerial photography was less conducive to bathymetric mapping in one of the basin considered. Of the four predictors of depth retrieval performance we evaluated (mean and standard deviation of depth, width, and an index of water clarity), only width was consistently significantly correlated with OBRA R2 (p < 0.026). Currently, BaMGRID is best‐suited for site‐by‐site analysis to support practical applications at the reach scale; continuous, basin‐wide mapping of river bathymetry will require additional research. Key Points: Combine depth measurements made during site visits to gaging stations with archived images to enable remote sensing of river bathymetryMultispectral satellite images acquired daily can yield highly accurate depth estimates, but high resolution air photos were less accurateBathymetric Mapping using Gage Records and Image Databases (BaMGRID) is well suited to site‐by‐site analysis for reach‐scale applications [ABSTRACT FROM AUTHOR]

Bridges are metal or concrete structures, which make road connections across rivers when installed over river paths. When flooding or scouring occurs, several issues including bridge destruction and interruption of road connections arise. There are a variety of methods of protecting such structures, one of which is application submerged vanes. This research shows how two vanes with different submergence ratio affected decrease in local scour surrounding one pier and groups of piers installed in a 180-degree bend. The scour around pier groups either in a transverse position to the flow or with a longitudinal direction was analyzed. This finding suggested that applying vanes decreased the deepest scour around the piers in all the tests, and its maximum effect occurred in triad longitudinal pier groups. By raising the submergence ratio, bed scour depth at the outer bank reached its minimum size in longitudinal pier groups. In transverse pier groups, the first scour hole near the outer bank increased in depth in the presence of vanes. By using the vanes, the slope of the scour hole towards the inner bank grew larger than that towards the other bank. The maximum slope of the outer bank happened in the triad transverse pier group at an approximate value of 0.63. The most significant impact of submerged vanes on reducing the upstream slope was observed in a single pier with 75% submerged vanes and triad longitudinal piers with 25% submerged vanes, resulting in reductions of about 50 and 74% respectively compared to piers without vanes. [ABSTRACT FROM AUTHOR]

The subdivision of Amazonia in large interfluvial areas of endemism (delimited by major rivers), based mostly on bird species distributions, has been a recurrent starting point to the understanding and conservation of the biome’s megadiversity. Yet, no areas of endemism or regionalization have been described for the well over 100 bird species that occupy floodplain habitats along the rivers, and thus are not expected to have ranges delimited by the rivers themselves. Here, through spatial analyses of updated range maps (based on a dataset with more than 80 thousand occurrence records), for a revised list of 182 floodplain specialized bird taxa, we identified ten areas of endemism and a complementary habitat-specific regionalization of the biome (with 13 regions). For the floodplain birds, Amazonian major rivers are segmented into distinct areas of endemism rather than these areas being delimited by the rivers. The well-established large interfluvial areas of endemism are appropriate for terra firme species but fail to account for taxa associated with floodplain habitats. Natural history traits and taxonomy of endemic species suggest that both ecological and historical processes have contributed to the patterns found. This new regionalization is consistent with the view of Amazonia as a mosaic of ecoregions and offers a complementary scheme for studies on the evolution and conservation of the floodplain component of its biodiversity.

Climate change-induced floods and flood disasters pose a serious threat to many settlements on a global scale. These disasters not only cause great damage to human life and economic activities, but also adversely affect the built environment. Factors such as increased rainfall due to climate change, destruction of agricultural lands and forest areas, infrastructure deficiencies, unpreparedness of settlements for natural disasters, wrong positioning and unplanned construction are effective in the occurrence of flood disasters. Therefore, in order to prevent flood disasters, it is necessary to adopt an integrated disaster management approach and develop effective and sustainable solutions in order to increase the flood resistance of settlements, especially on the banks of rivers, and to reduce the impacts against possible disasters. In this study, firstly, the floods that occurred in Bozkurt, Ayancık and İnebolu-Özlüce in 2021 were analyzed. Based on these findings, the causes of flood disasters that occurred in Inebolu in 2022 and 2023 were investigated in the field research section. Qualitative data analysis method was used as a method in the study. In addition, in the examination of the sample areas, the damages were examined through observation with the help of photographs. Flood hazard risks were examined in accordance with the flood management plans in the sample areas determined within the scope of the study and problems were identified as a result of the findings obtained. The identified problems were evaluated within the scope of planning, design principles and legal and administrative framework. As a result, recommendations are presented for making river coastal settlements resistant to flood disasters.

Lotic systems are rapidly changing due to anthropogenic impacts, making it crucial to note the diversity and abundance of Odonates for effective conservation of these running waters. Our study aimed to assess and compare the Odonate communities in two adjacent rivers, Medjerda and Cheref, in Souk Ahras, northeastern Algeria collected during the period from January 2022 to August 2023. In total, 27 species belonging to 7 families and 17 genera were recorded, with three rare species in Numidia, and three Maghrebian endemic species, including Gomphus lucasii (Selys, 1850) listed as “Vulnerable” in the IUCN Mediterranean Red List. Coenagrion mercuriale (Charpentier, 1840), a locally endangered species, was abundantly present in the Medjerda River. Additionally, the presence of the desert species Trithemis kirbyi (Selys, 1891) in Medjerda confirms their northward expansion within Algeria. The Libellulidae were the most dominant family with 11 species. Our findings revealed no significant differences in terms of biodiversity indices (Richness, Simpson, Shannon, & Pielou's evenness) between the two rivers. However, significant dissimilarities were observed in Odonate assemblages likely due to habitat and environmental variations. Many factors, such as water pumping, overgrazing, untreated wastewater, and riverbank development, which influence Odonate species, were observed in the two rivers. Consequently, an urgent conservation plan should be put in place to preserve water resources and biodiversity in the region. This study highlights the need for continued monitoring and conservation efforts, especially for rare and threatened species in the face of increasing anthropogenic pressures on these aquatic ecosystems.

Aquatic bryophytes are frequently used as bioindicators of water quality in rivers. Poor water quality increases physiological stress in moss, and stress levels can be estimated by measuring the concentrations of photosynthetic pigments and by calculating pigmentary indices. However, studies collecting many samples in a short time may need to store them until analysis. In the meantime, the pigments may suffer some degradation. Given the lack of studies on this problem for aquatic bryophytes, this one investigates the effect of three storage methods (refrigerated at 6 °C, frozen at − 20 °C and dried at room temperature) on the concentrations of chlorophyll a, chlorophyll b, pheophytin a and the following ratios: chlorophyll a/chlorophyll b, D430/D410, D665/D665a, D430/D665 and D480/D665 (where Dx is the absorbance at x nm) in the aquatic moss Fontinalis antipyretica. The results showed that refrigeration was the most suitable method, freezing might be suitable for some parameters, and drying was inadequate for this purpose. We recommend that all studies on photosynthetic pigments detail the time elapsed from collection to sample analysis, as well as the storage method used. [ABSTRACT FROM AUTHOR]

The Caucasus is characterized by the large and at the same time increasing load from exploited metal and non-metallic mines. The sanitary-hygienic and toxic danger to people and the environment is quite high. There are 44 metal ores in the Syunik Region, and more than 90 non-metal deposits. In 2018, 12 metal and 29 non-metallic deposits were granted with the use rights for the purpose of mineral extraction. Also, geological survey permission was granted for 12 metal deposits. Currently, there are 12 operating and conserved tailings filled with about 400 million m3 of tailings, which are equipped with many heavy metals and other dangerous substances, as the result of the exploitation of the metal mines in Syunik. The present study focuses on the ecological assessment of the waters of the Voghji and the Khalaj Rivers that are located in the technogenic polluted zone of the Caucasus. The research revealed that along with the increase of the volumes of the Kapan-Qajaran copper-molybdenum mines, as well as the increase of the rock dumps and tailings, the organoleptic-chemical indicators of the waters of the Voghji and the Khalaj Rivers had increased. The quantity of the suspended particles and the heavy metals in the waters of these rivers had increased 1.5 and 2.0 times or by 58–100 % and 19.5 − 29.8 %, respectively, in the last 10 years. The trends are also observed in the values of the sulfates, the total dissolved salts, and the electrical conductivity, which are due to the chemical composition of the ores and the improper management of the acid drainage. The content of the heavy metals in the waters of the mentioned rivers is 9 − 20 times higher than the permissible limit density, and the degree of the mineralization is above the permissible limit. Thus, the waters of these rivers, after mixing with the effluent from the mining industry, are not guaranteed to be used for irrigation. Considering that the mobility of the heavy metals decreases several times in the alkaline environment (pH 8.5 − 9.0), it is recommended that the mining industry constantly adds lime (CaO) to the acid drainage of the mines so that the pH of the water become lower: from acid to alkaline (pH 8.5 − 9.0) and only after that, the water could be used for irrigation of the agricultural crops. This is possible for many types of heavy metals, including when using other wastewater treatment measures: engineering, physicochemical and biological.

Abstract 137Cs is a long-lived man-made radionuclide introduced in the environment worldwide at the early beginning of the nuclear Era during atmospheric nuclear testing’s followed by the civil use of nuclear energy. Atmospheric fallout deposition of this major artificial radionuclide was reconstructed at the scale of French large river basins since 1945, and trajectories in French nuclearized rivers were established using sediment coring. Our results show that 137Cs contents in sediments of the studied rivers display a large spatial and temporal variability in response to the various anthropogenic pressures exerted on their catchment. The Loire, Rhone, and Rhine rivers were the most affected by atmospheric fallout from the global deposition from nuclear tests. Rhine and Rhone also received significant fallout from the Chernobyl accident in 1986 and recorded significant 137Cs concentrations in their sediments over the 1970–1985 period due to the regulatory releases from the nuclear industries. The Meuse River was notably impacted in the early 1970s by industrial releases. In contrast, the Seine River display the lowest 137Cs concentrations regardless of the period. All the rivers responded similarly over time to atmospheric fallout on their catchment, underlying a rather homogeneous resilience capacity of these river systems to this source of contamination.

Rivers provide key ecosystem services that are inherently engineered and optimized to meet the strategic and economic needs of countries around the world. However, limited water quality records of a full river continuum hindered the understanding of how river systems response to the multiple stressors acting on them. This study highlights the use of Sentinel-2 Multi-Spectral Imager (MSI) data to monitor changes in water color in two optically complex river systems: the Yangtze and Danube using the Forel-Ule Index (FUI). FUI divides water color into 21 classes from dark blue to yellowish brown stemming from the historical Forel-Ule water color scale and has been promoted as a useful indicator showing water turbidity variations in water bodies. The results revealed contrasting water color patterns in the two rivers on both spatial and seasonal scales. Spatially, the FUI of the Yangtze River gradually increased from the upper reaches to the lower reaches, while the FUI of the Danube River declined in the lower reaches, which is possibly due to the sediment sink effect of the Iron Gate Dams. The regional FUI peaks and valleys observed in the two river systems have also been shown to be related to the dams and hydropower stations along them. Seasonally, the variations of FUI in both systems can be attributed to climate seasonality, especially precipitation in the basin and the water level. Moreover, land cover within the river basin was possibly a significant determinant of water color, as higher levels of vegetation in the Danube basin were associated with lower FUI values, whereas higher FUI values and lower levels of vegetation were observed in the Yangtze system. This study furthers our knowledge of using Sentinel-2 MSI to monitor and understand the spatial-temporal variations of river systems and highlights the capabilities of the FUI in an optically complex environment.

Abstract Under warming conditions and with increasing human perturbations, rivers across the globe are facing drastic shifts in their hydrologic regime, resulting in fragmentation and disconnection from the catchment. Subsequently, a dependency on in situ primary productivity as the source of organic matter increases and warrants detailed investigation of the nature of primary production in urbanized river systems. In this study, primary productivity was estimated at multiple locations along the continuum of an engineered (Sabarmati) and a free flowing (Mahi) river systems in India using 13C tracer incubation method. Significantly enhanced primary productivity in the riverfront (engineered construction along the Sabarmati that holds water supplied by a canal) and polluted downstream of the Sabarmati compared to free flowing Mahi was observed. It was also observed that water stagnancy, temperature, and nutrient availability were the key factors regulating the rates of primary productivity in the urban river system. The study highlights the salient features of riverine primary productivity associated with engineered modifications, which needs to be considered for future river development projects.

Source‐to‐sink transfer of sediment and organic carbon (OC) is regulated by river mobility. Quantifying trends in river mobility is, however, challenging due to diverse planform morphologies (e.g., meandering, braided) and measurement methods. Here, we utilize a remote‐sensing method applicable to all planform morphologies to quantify the mobility timescales of 80 rivers worldwide. Results show that, across the continuum from meandering to braided rivers, there is a systematic reduction in the timescales of channel mobility and—to a lesser extent—floodplain reworking. This leads to a decrease in the efficiency with which braided rivers rework old floodplain material compared to their meandering counterparts. Reduced floodplain reworking efficiency of braided rivers leads to smaller channel‐belt areas relative to their size. Results suggest that river‐mobility timescales derived from remote sensing can aid in the characterization of sediment and OC storage and transit times at a global scale. Plain Language Summary: Rivers transport sediment and organic carbon (OC) from the mountains to the sea, and river movement affects sediment and OC transit times in landscapes. Understanding the controls on timescales of river movement is critical for assessing how fluvial processes influence the terrestrial carbon cycle. While previous work has quantified different river planform shapes on the Earth's surface (e.g., meandering, wandering, and braided), little is known about how the pace and nature of river movement is different between river planform shapes. This is because we lack methods to measure and compare river movement across different river planform shapes. Here, we leverage a tool to quantify river movement from time series of satellite imagery that is equally applicable to all river planform shapes. We apply this method to calculate the timescales of river movement of 80 rivers worldwide for the last 37 years. We show that (a) braided rivers migrate faster than meandering rivers, and (b) braided rivers move over a smaller area relative to their size. Comparing results with geochemical observations from the Río Bermejo—a well‐studied river for sediment‐OC cycling—we show that our mobility framework may provide a new way to assess sediment and OC storage timescales in floodplains. Key Points: We quantify timescales of floodplain reworking and channel‐overlap decay from satellite imagery of 80 rivers worldwideFrom meandering to braided planform morphology, there is a reduction in the overlap timescale and the reworking timescaleMobility timescales provide a means for remotely quantifying terrestrial‐sediment and organic‐carbon storage and transit [ABSTRACT FROM AUTHOR]

We consider unconfined flow in aquifers with a small sloping base, a magnitude of no more than a few percent at maximum and aim the analysis to large-scale regional modeling using analytic elements. We write the equations for the vertically integrated discharge, and find that the resulting two-dimensional discharge vector is rotational, as opposed to the specific discharge vector. We propose an approximate model for describing three-dimensional flow in an aquifer with a sloping base, and apply the approach to cases of flow between two parallel rivers and flow with a well in an aquifer bounded by a long river. We apply Wirtinger calculus and are able to estimate the error due to the approximation. [ABSTRACT FROM AUTHOR]

The Caucasus is characterized by the large and at the same time increasing load from exploited metal and non-metallic mines. The sanitary-hygienic and toxic danger to people and the environment is quite high. There are 44 metal ores in the Syunik Region, and more than 90 non-metal deposits. In 2018, 12 metal and 29 non-metallic deposits were granted with the use rights for the purpose of mineral extraction. Also, geological survey permission was granted for 12 metal deposits. Currently, there are 12 operating and conserved tailings filled with about 400 million m3 of tailings, which are equipped with many heavy metals and other dangerous substances, as the result of the exploitation of the metal mines in Syunik. The present study focuses on the ecological assessment of the waters of the Voghji and the Khalaj Rivers that are located in the technogenic polluted zone of the Caucasus. The research revealed that along with the increase of the volumes of the Kapan-Qajaran copper-molybdenum mines, as well as the increase of the rock dumps and tailings, the organoleptic-chemical indicators of the waters of the Voghji and the Khalaj Rivers had increased. The quantity of the suspended particles and the heavy metals in the waters of these rivers had increased 1.5 and 2.0 times or by 58–100 % and 19.5 − 29.8 %, respectively, in the last 10 years. The trends are also observed in the values of the sulfates, the total dissolved salts, and the electrical conductivity, which are due to the chemical composition of the ores and the improper management of the acid drainage. The content of the heavy metals in the waters of the mentioned rivers is 9 − 20 times higher than the permissible limit density, and the degree of the mineralization is above the permissible limit. Thus, the waters of these rivers, after mixing with the effluent from the mining industry, are not guaranteed to be used for irrigation. Considering that the mobility of the heavy metals decreases several times in the alkaline environment (pH 8.5 − 9.0), it is recommended that the mining industry constantly adds lime (CaO) to the acid drainage of the mines so that the pH of the water become lower: from acid to alkaline (pH 8.5 − 9.0) and only after that, the water could be used for irrigation of the agricultural crops. This is possible for many types of heavy metals, including when using other wastewater treatment measures: engineering, physicochemical and biological. [ABSTRACT FROM AUTHOR]

Cutting-edge technology for fluvial monitoring has revolutionised the field, enabling more comprehensive data collection, analysis, and interpretation. Traditional monitoring methods were limited in their spatial and temporal resolutions, but advancements in remote sensing, unmanned aerial systems (UASs), and other innovative technologies have significantly enhanced the fluvial monitoring capabilities. UASs equipped with advanced sensors enable detailed and precise fluvial monitoring by capturing high-resolution topographic data, generate accurate digital elevation models, and provide imagery of river channels, banks, and riparian zones. These data enable the identification of erosion and deposition patterns, the quantification of sediment transport, the evaluation of habitat quality, and the monitoring of river flows. The latter allows us to understand the dynamics of rivers during various hydrological events, including floods, droughts, and seasonal variations. This manuscript aims to provide an update on the main research themes and topics in the literature on the use of UASs for river monitoring. The latter is achieved through a bibliometric analysis of the publication trends and identifies the field's key themes and collaborative networks. The bibliometric analysis shows trends in the number of publications, number of citations, top contributing countries, top publishing journals, top contributing institutions, and top authors. A total of 1085 publications on UAS monitoring in rivers are identified, published between 1999 and 2023, showing a steady annual growth rate of 24.44%. Bibliographic records are exported from the Web of Science (WoS) database using a comprehensive set of keywords. The bibliometric analysis of the raw data obtained from the WoS database is performed using the R software. The results highlight important trends and valuable insights related to the use of UASs in river monitoring, particularly in the last decade. The most frequently used author keywords outline the core themes of UASs monitoring research and highlight the interdisciplinary nature and collaborative efforts within the field. "River", "topography", "photogrammetry", and "Structure-from-Motion" are the core themes of UASs monitoring research. These findings can guide future research and promote new interdisciplinary collaborations. [ABSTRACT FROM AUTHOR]

Sediment ratings supply an important input to the design of water resources projects. Nevertheless, the accuracy of sediment ratings has remained a matter of concern for hydrologists. The present article investigates both the aspect of improving the accuracy, i.e., modifying the simple rating curve equation by introducing a four-parameter equation and application of ensemble machine learning (ML) and ensemble empirical models, to estimate sediment loads. The ML models include artificial neural networks, multi-gene genetic programming (MGGP), and a hybrid MGGP-based model. Published field data at two measuring stations were used to assess the performance of different models employed in this study. The comparative analysis conducted in this study provides a novel comparison of sediment load estimations for three time scales. For instance, the ML-based simple average ensemble model (i.e., 556.5, 255.0, and 0.759) and the empirical-based nonlinear ensemble model (i.e., 549.1, 378.6, and 0.589) achieved the lowest root-mean-square errors and mean absolute errors and highest determination coefficients for the train and test monthly sediment data of the first station, respectively. Finally, the findings demonstrate that ensemble-based models generally improve the estimates of sediment loads at daily, 10-daily, and monthly scales. [ABSTRACT FROM AUTHOR]

Rivers provide key ecosystem services that are inherently engineered and optimized to meet the strategic and economic needs of countries around the world. However, limited water quality records of a full river continuum hindered the understanding of how river systems response to the multiple stressors acting on them. This study highlights the use of Sentinel-2 Multi-Spectral Imager (MSI) data to monitor changes in water color in two optically complex river systems: the Yangtze and Danube using the Forel-Ule Index (FUI). FUI divides water color into 21 classes from dark blue to yellowish brown stemming from the historical Forel-Ule water color scale and has been promoted as a useful indicator showing water turbidity variations in water bodies. The results revealed contrasting water color patterns in the two rivers on both spatial and seasonal scales. Spatially, the FUI of the Yangtze River gradually increased from the upper reaches to the lower reaches, while the FUI of the Danube River declined in the lower reaches, which is possibly due to the sediment sink effect of the Iron Gate Dams. The regional FUI peaks and valleys observed in the two river systems have also been shown to be related to the dams and hydropower stations along them. Seasonally, the variations of FUI in both systems can be attributed to climate seasonality, especially precipitation in the basin and the water level. Moreover, land cover within the river basin was possibly a significant determinant of water color, as higher levels of vegetation in the Danube basin were associated with lower FUI values, whereas higher FUI values and lower levels of vegetation were observed in the Yangtze system. This study furthers our knowledge of using Sentinel-2 MSI to monitor and understand the spatial-temporal variations of river systems and highlights the capabilities of the FUI in an optically complex environment. [ABSTRACT FROM AUTHOR]

The objective of the current research was to examine the water quality of the River Ravi and the River Sutlej, with a specific focus on potentially toxic elements (PTEs). Additionally, we sought to monitor the sources of pollution in these rivers by gathering samples from the primary drains that carry industrial and municipal waste into these water bodies. Furthermore, we aimed to evaluate the impact of PTEs in surface water on groundwater quality by collecting groundwater samples from nearby populated areas. A total of 30 samples were collected from these three sources: rivers (6 samples), drains (9 samples), and groundwater (15 samples). The analysis revealed that the levels of PTEs in the samples from these three resources having a mean value: arsenic (As) 23.5 µg/L, zinc (Zn) 2.35 mg/L, manganese (Mn) 0.51 mg/L, lead (Pb) 6.63 µg/L, and chromium (Cr) 10.9 µg/L, exceeded the recommended values set by the World Health Organization (WHO). Furthermore, PTEs including (As 84%), (Zn 65%), (Mn 69%), (Pb 53%), (Cr 53%), and (Ni 27%), samples were beyond the recommended values of WHO. The results of the Principal Component Analysis indicated that surface water and groundwater exhibited total variability of 83.87% and 85.97%, respectively. This indicates that the aquifers in the study area have been contaminated due to both natural geogenic factors and anthropogenic sources. These sources include the discharge of industrial effluents, wastewater from municipal sources, mining activities, agricultural practices, weathering of rocks, and interactions between rocks and water. Spatial distribution maps clearly illustrated the widespread mobilization of PTEs throughout the study area. Furthermore, a health risk assessment was conducted to evaluate the potential adverse health effects of PTEs through the ingestion of drinking groundwater by both children and adults. Health risk assessment result show the mean carcinogenic values for As, Cr, Pb and Ni in children are calculated to be (1.88E-04), (2.61E-04), (2.16E-02), and (5.74E-05), respectively. Similarly, the mean carcinogenic values for the above mentioned PTEs in adults were recorded to be (2.39E-05), (3.32E-05), (1.19E-03), and (7.29E-06) respectively. The total hazard index values for As, Zn, Cr, Pb, Mn, Cu, and Ni in children were observed to be (9.07E + 00), (9.95E-07), (4.59E-04), (5.75E-04), (4.72E-05), (2.78E-03), and (5.27E-05) respectively. The analysis revealed that As has an adverse effect on the population of the study area as compared to other PTEs investigated in this study. [ABSTRACT FROM AUTHOR]

Introduction: Information on spatial patterns of water depth in river channels is valuable for numerous applications, but such data can be difficult to obtain via traditional field methods. Ongoing developments in remote sensing technology have enabled various image-based approaches for mapping river bathymetry; this study evaluated the potential to retrieve depth from multispectral images acquired by an uncrewed aircraft system (UAS). Methods: More specifically, we produced depth maps for a 4 km reach of a clearflowing, relatively shallow river using an established spectrally based algorithm, Optimal Band Ratio Analysis. To assess accuracy, we compared image-derived estimates to direct measurements of water depth. The field data were collected by wading and from a boat equipped with an echo sounder and used to survey cross sections and a longitudinal profile. We partitioned our study area along the Sacramento River, California, USA, into three distinct sub-reaches and acquired a separate image for each one. In addition to the typical, self-contained, per-image depth retrieval workflow, we also explored the possibility of exporting a relationship between depth and reflectance calibrated using data from one site to the other two sub-reaches. Moreover, we evaluated whether sampling configurations progressively more sparse than our full field survey could still provide sufficient calibration data for developing robust depth retrieval models. Results: Our results indicate that under favorable environmental conditions like those observed on the Sacramento River during low flow, accurate, precise depth maps can be derived from images acquired by UAS, not only within a sub-reach but also across multiple, adjacent sub-reaches of the same river. Discussion: Moreover, our findings imply that the level of effort invested in obtaining field data for calibration could be significantly reduced. In aggregate, this investigation suggests that UAS-based remote sensing could facilitate highly efficient, cost-effective, operational mapping of river bathymetry at the reach scale in clear-flowing streams. [ABSTRACT FROM AUTHOR]

Pollution of water bodies with heavy metals can lead to the death of fish and other aquatic organisms, a decrease in biodiversity and a threat to ecosystems, emphasising the importance of preserving the natural environment; pollution of water bodies can have serious economic consequences, in particular, a decrease in profits from fishing, tourism, and other activities related to water use, which requires the development of water management strategies. The purpose of the study was to determine the general trends in the content of heavy metals in the surface waters of the Teteriv River and fattening pond No. 1 of the LLC "SHF INTERRYBHOSP". Water samples were taken at the stream of the Teteriv River (Vidsichne Reservoir) and in the fattening pond No. 1 at a depth of 0.2-0.5 m from the surface for further laboratory analysis of the content of heavy metal ions (HM). The atomic absorption method of analysis was used to study water. Laboratory studies of surface waters in the Teteriv River and pond were performed according to the following indicators: hydrogen index (pH), lead, cadmium, manganese, zinc, and iron content. The results of the study of the content of heavy metals in the Teteriv River are presented, which showed that the content of such heavy metals as: Pb, Cd, Mn, Zn and Fe, in river water, with the exception of iron, exceed the limits of maximum admissible values of water quality indicators for fishery water bodies. Background HM indicators from fattening pond No. 1 did not show an excess of the MAC (maximum admissible concentration). High concentrations of lead, cadmium, manganese, and iron are explained by powerful anthropogenic pollution, the source of which is agricultural and industrial complexes of Zhytomyr Oblast. The results can be used to establish effective monitoring of water quality in reservoirs and develop strategies to reduce pollution in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Plastic pollution is now recognised as a growing concern for both the environment and associated biota. Consequently, a plethora of scientific reports are being produced regarding the occurrence, distribution, and transfer pathways of litter particles. However, there are scientific gaps that need to be filled regarding micro- and nanoplastic impacts on marine and freshwater organisms. This Special Issue (SI) aimed to provide an update on plastic pollution and its consequences on aquatic ecosystems, with a particular focus on biological domains, by adopting a multidisciplinary perspective. Several research articles and reviews were collected, focusing on the origin, fate, and effects of plastics in marine and freshwater environments, along with their interactions with biotic components. We believe this SI will contribute to the development of new studies on plastic pollution and the elaboration of science-based policies at different levels of our modern society. [ABSTRACT FROM AUTHOR]

This study aimed to optimize the methods for sampling and analyzing methylmercury (MeHg) concentrated within diffusive gradients in thin films (DGT) and its application to different water bodies. We explored the elution solution for MeHg, comprised of 1.13 mM thiourea and 0.1M HCl, optimizing its volume to 50 mL. In addition, we found that it is necessary to analyze the entire extraction solution after adjusting its pH, to ensure completion of the ethylation reaction. The DGT samplers were deployed in two distinct aquatic environments (i.e., Okjeong Lake and Nakdong River) for up to 6 weeks, and this study demonstrated to predict the time-weighted average concentration with a diffusion coefficient of 7.65 × 10−6 cm2 s−1 for MeHg in the diffusive gel. To assess the diffusive boundary layer (DBL) effects, the DGT samplers with different agarose diffusive gel thickness were deployed. The mass of MeHg accumulated in the DGT resin at a given time decreased with increasing diffusive gel thickness, because of creating longer diffusion pathways within thicker gels. The labile MeHg concentration estimated by the DGT in Okjeong Lake and Nakdong River are found in the range of 61–111 and 55–105 pg L−1, respectively, which were found to be similar to the grab sampling data. Additionally, this study evaluated depth-dependent MeHg in Okjeong Lake. The vertical profile results showed that the concentration of MeHg at the depth of 2.3 and 15.7 m are about 1.5 and 4.6 times of the DGT installed at 0.3 m of the surface layer, respectively, suggesting potential mercury methylation in deep waters. These findings have practical implications for predicting bioavailability, assessing risks, and formulating strategies for water body management and contamination remediation. [ABSTRACT FROM AUTHOR]

Iron (Fe) is one of the main nutrients present in dissolved, suspended, and colloidal states in river water. Predicting the composition and size of dissolved Fe compounds is crucial for assessing water quality. In this stud, we used a combination of physical methods (filtration), chemical techniques (ion exchange chromatography), and thermodynamic modeling (Visual MINTEQ) to characterize dissolved Fe speciation in boreal organic-rich rivers across a sizable south–north transect. We chose contrasting rivers with a predominance of either allochthonous or autochthonous organic compounds. We found that the dissolved organic matter (DOM) in the studied rivers varies in molecular weights and the degree of humification. Regardless of the climate parameters of the river watershed, the dominant status of dissolved Fe during the summer low-water period was essentially colloidal and dominated by anionic complexes of the type [MeL]n−. [ABSTRACT FROM AUTHOR]