River Water Bodies Research Articles

Effect of Aqueous Extract of Ichthyotoxic Plant Bridelia micrantha (Hochst) (Baill) on Haematology, Histopathology and Carcass Characteristics of African Catfish (Clarias gariepinus) (BURCHELL, 1822) Juvenile

The Bridelia micrantha (Hochst.) (Phyllanthaceae) is an ichthyotoxic plant used in catching fish in Nigeria. The toxicity of aqueous extract of B. micrantha on Clarias gariepinus was investigated under statics bioassay conditions. The concentrations of the leaves extract used were 0.00, 0.10, 0.20, 0.30, 0.40, 0.50 and 0.0.60ml/l. The 24hrs, 36hrs, 48hrs, 72hrs, and 96hrs LC50 were 0.40mg/l, 0.30mg/l, 0.26mg/l, 0.22mg/l and 0.21mg/l respectively, with the range of maximum admissible concentration (MATC) were 0.004 – 0.04, 0.003 – 0.03, 0.0026 – 0.026, 0.0022 – 0.022, and 0.0021 – 0.021 respectively. The opercula ventilation and loss of reflex increased with an increase in the concentrations of the leaves extract at the end of 96-hour exposure period. Respiratory distress, loss of balance, settling at the bottom motionless and erratic swimming was observed before death during the exposure period. There was no significant difference in physicochemical parameters of test media (P<0.05) before, during and after the experimental period. Total Dissolved Solids and Conductivity increased significantly (p<0.05) with increase in extract concentration. Temperature had nonsignificant (p<0.05) reduction at all extract concentrations. Blood analysis revealed significant (P<0.05) reduction in the blood parameters (Haemoglobin, Packed Cell Volume, Red Blood Cells, White Blood Cells, Platelet, Mean Corpuscular Volume and Mean Corpuscular Haemoglobin) of exposed fish. There was severe reduction in Carcass/Proximate (Moisture, Crude Protein, Crude Lipid, Ash, NFE, and Energy) composition of Clarias gariepinus juvenile exposed to B. micrantha. Histopathological examinations of the test fish showed some pathological disruptions, such as skin layer with severe superficial spreading of melanoma, The liver cells revealed hepatic tissue with severe ground glass (GG) appearance of the cytoplasm and intra hepatic hemorrhage (IHH), The gill showed severe effect on the gill architecture with hypertrophy of the gill arch, gill filament and aggregate of inflammation (AI), while the kidney revealed severe degeneration of the renal tissue with severe intra renal necrosis (TN). The result of this study calls for the need to discourage the use of toxic plants for catching fish in Cross River and Nigeria water bodies.

Preliminary Research on Tourism Landscape Planning in Nanchang River Section from the Third Space Perspective

In recent years, there has been a growing emphasis on the Three Mountains and Five Gardens scenic area in Haidian District, Beijing. While prioritizing the preservation of cultural heritage sites, efforts have been made to enhance green landscapes and ecological governance. However, the landscape of the Yangtze River water body, surrounding greenery, and overall promotion within the Three Mountains and Five Gardens area have remained limited to improvements within individual parks. Building upon the "Overall Protection Plan of Three Mountains and Five Parks Area (2019-2035)" organized by the Beijing Municipal Planning Commission and the Haidian District People's Government, this paper aims to explore and address the current issues in the tourism landscape planning of the Nanchang River section. These issues include insufficient landscape promotion, transportation inconveniences, and a lack of diverse tourism offerings. In the research context of "Building Beijing's 'Third Space' in the Three Mountains and Five Parks Area," corresponding solutions and comparative advantages will be proposed. Ultimately, a preliminary concept for an in-depth and feasible overall planning of the Nanchang River section will be presented.

Bioanalytical and chemical characterization of organic micropollutant mixtures in long-term exposed passive samplers from the Joint Danube Survey 4: Setting a baseline for water quality monitoring

Monitoring methodologies reflecting the long-term quality and contamination of surface waters are needed to obtain a representative picture of pollution and identify risk drivers. This study sets a baseline for characterizing chemical pollution in the Danube River using an innovative approach, combining continuous three-months use of passive sampling technology with comprehensive chemical (747 chemicals) and bioanalytical (seven in vitro bioassays) assessment during the Joint Danube Survey (JDS4). This is one of the world's largest investigative surface-water monitoring efforts in the longest river in the European Union, which water after riverbank filtration is broadly used for drinking water production. Two types of passive samplers, silicone rubber (SR) sheets for hydrophobic compounds and AttractSPETM HLB disks for hydrophilic compounds, were deployed at nine sites for approximately 100 days. The Danube River pollution was dominated by industrial compounds in SR samplers and by industrial compounds together with pharmaceuticals and personal care products in HLB samplers. Comparison of the Estimated Environmental Concentrations with Predicted No-Effect Concentrations revealed that at the studied sites, at least one (SR) and 4–7 (HLB) compound(s) exceeded the risk quotient of 1. We also detected AhR-mediated activity, oxidative stress response, peroxisome proliferator-activated receptor gamma-mediated activity, estrogenic, androgenic, and anti-androgenic activities using in vitro bioassays. A significant portion of the AhR-mediated and estrogenic activities could be explained by detected analytes at several sites, while for the other bioassays and other sites, much of the activity remained unexplained. The effect-based trigger values for estrogenic and anti-androgenic activities were exceeded at some sites. The identified drivers of mixture in vitro effects deserve further attention in ecotoxicological and environmental pollution research. This novel approach using long-term passive sampling provides a representative benchmark of pollution and effect potentials of chemical mixtures for future water quality monitoring of the Danube River and other large water bodies.

Methodological Framework for Assessing Hydromorphological Conditions of Heavily Modified and Artificial River Water Bodies in Croatia

Water Framework Directive (WFD) guidance documents from 2019 provide a comprehensive review of methods and guidelines to improve the comparability of heavily modified water bodies (HMWBs) in the European Union. However, there is currently no common, single methodology for monitoring HMWBs and artificial water bodies (AWBs) or for determining maximum (MEP) and good ecological potential (GEP). This study presents the first assessment of hydromorphological conditions of HMWBs and AWBs in Croatia based on type-specific indicators. The typology of HMWBs and AWBs was based on distinct hydromorphological characteristics and modifications in order to be easily related to the uses of the water bodies. The classes of hydromorphological potential were graded from the theoretical MEP, which was determined by the score scale as the tolerated deviation from natural reference conditions, considering potential mitigation measures. The use of the water body and/or the effects on the wider environment were considered while determining MEP and choosing indicators included in monitoring and assessment. In the case of AWBs, the parameters dependent on natural reference conditions, which are non-existent, were omitted from the assessment. Only 27% of HMWBs and 2 out of 51 AWBs achieved good potential for all three hydromorphological elements. The most significant hydromorphological modifications include channelization, straightening, deepening and removal of riparian vegetation due to flood-protection management practices. In order to achieve the environmental objectives set out by the WFD, the Croatian water management system has to start implementing mitigation measures, especially related to natural flood management.

Occurrence, Potential Risk Assessment, and Source Apportionment of Polychlorinated Biphenyls in Water from Beiluo River

Polychlorinated biphenyls (PCBs) are highly hazardous, persistent, and bioaccumulative substances that pose a threat to water quality in a number of locations, including the Beiluo River in Shaanxi Province, China. However, little is known about the contribution of PCBs to the Beiluo River. In this study, in order to look into the impact of sources on the water of the Beiluo River, the discovered PCB congeners in water were examined on a regional scale. The concentration of PCBs in water across Beiluo River was in the range from 0.065 to 1.92 ng L−1, and the average concentration was 0.37 ng L−1. The main PCB sources in the Beiluo River waterbody were found using positive matrix factorization (PMF). Source apportionment results indicated that the PCB pollution of the Beiluo River was mostly caused by industrial emissions, technical PCB mixtures, and coal and wood combustion. According to current ecological risk assessment guidelines, the PCB concentrations found in this study may have a negative impact on biological systems. Overall, the new information about the presence of several PCBs in the water of the Beiluo River justifies the need for urgent management actions, as well as long-term monitoring efforts, to protect ecosystems. Future investigations of these chemicals in China may use the conclusions of this first ecological risk level assessment on the PCB contamination in the waterbody of the Beiluo River as a guide.

Post-Construction, Hydromorphological Cumulative Impact Assessment: An Approach at the Waterbody Level Integrating Different Spatial Scales

The environmental impact assessment is a process required in many countries. It highlights future activities with a significant impact on the environment. Water, as an environmental factor, needs adequate methods for quantifying cumulative impact of hydrotechnical works. In most cases, for new developments, baseline data is collected before the beginning of the construction, but for waterworks already in place, a different approach is needed. In line with the EU Water Framework Directive (Directive 2000/60/EC), the overall purpose of the research is to develop an approach for the hydromorphological cumulative impact assessment integrating different spatial scales for existing water intakes with transversal barriers on mountain rivers in Romania. Being a research study developed for a specific issue—post-construction impact assessment, some innovative actions were required. Lack of information in the pre-construction phase was an important constraint. Customizing formulas of certain indicators established within the Romanian method for hydromorphological status assessment of rivers proved to be a practical solution to show both local and waterbody hydromorphological impact. Upscaling the impact from the local scale to the river sector and the waterbody allows awareness of the spatial extent of the impact and understanding of the importance of the thresholds of significant impact for a broader audience. In order to better highlight the approach, this paper shows practical examples. The whole chain of the drivers–pressures–state–impacts–responses (DPSIR) framework is applied in the case of two river water bodies with hydropower generation facilities in place. In addition, some recommendations for actions are provided.

Partially saturated vertical flow constructed wetland for urban wastewater treatment

Partially saturated vertical flow constructed wetland (SVF) emerge as an alternative to classical vertical flow due to improved carbonaceous organic matter removal and nitrogen transformations without of the need for external energy source. In this context, the main objective of this study was to show the long-term evaluation of a SVF wetland with 7.5 m2 of surface area (filter media depth of 0.75 m where 53% of total depth was saturated) and planted with Typha domingensis macrophyte, operated as secondary/advanced treatment unit of urban wastewater under subtropical climate conditions. Sampling and analysis of conventional wastewater quality parameters, oxygen consumption rate estimation, and assessment of bacterial dynamics were conducted over 6 years, which allowed inferring that operating the SVF wetland with a specific hydraulic load around 4 L∙m-2∙min-1 and hydraulic regime with feeding and resting cycles of 3.5 d, all wastewater quality parameters met local legislation release standards in river water bodies. Saturated zone of the wetland favors the presence of denitrifying bacteria representing a potential of 44% of TN removal due to simultaneous nitrification-denitrification.

River Valleys and Water Bodies in the Cosmos of the Idu Mishmis of Arunachal Pradesh

River Valleys and Water Bodies in the Cosmos of the Idu Mishmis of Arunachal Pradesh

Analysis of The Impact of Bone Sugar Factory Waste Water On Quality of Teko River Water

The Bone sugar factory discharges its liquid waste into the Teko River water body. The Teko River is widely used for agricultural and fishery purposes, so it is necessary to maintain the quality of the water to suit its designation. Liquid waste from the Bone sugar factory can affect the water quality of the Teko River. The purpose of this study was to determine the water quality status of the Teko River due to the discharge of waste water from the Bone sugar factory. Observations were made on the water body of the Teko River from the up stream and down stream of the disposal of sugar factory wastewater at 3 stations. Station 1 is the point before the discharge of wastewater, station 2 is the point of discharge of wastewater and station 3 is the point after discharge of wastewater, the recipient of the impact. The results of the research conducted on the Teko river water body showed that the status of water quality at station 1 was the category of lightly polluted, station 2 was in the category of lightly polluted and station 3 was in the category of meeting quality standards. Determination of water quality using the Pollution Index method according to Minister of Environment Decree Number 115 of 2003 using class II river water quality standards according to Government Regulation Number 22 of 2021quality standards according to Government Regulation Number 22 of 2021.

Analysis of the Contribution of TSS, pH, Fe, and Mn Parameters to the Pollution Load Capacity of Coal Mines in the Oal River, South Sumatra

The Oal River receives coal wastewater input at several companies. Coal mining in the vicinity of the location adds to the burden of water pollution in the Oal River due to waste water disposal activities. The increase in the concentration of coal waste and the pollution load that enters the Oal River water body will have an impact on the reducing capacity of the pollution load. This study aim to provide information on the condition of the pollution load carrying capacity of the Oal River. Determination of the carrying capacity of water pollution loads at water sources using the mass balance method. The characteristic of the Oal River water with the parameters TSS, pH, Fe and Mn have not yet passed the quality standards for river water and wastewater, both according to PP No. 22 of 2021 and South Sumatra Governor Regulation No. 8 of 2012. The Oal River still has the capacity to accommodate TSS and pH parameters.

Multiwater Index Synergistic Monitoring of Typical Wetland Water Bodies in the Arid Regions of West-Central Ningxia over 30 Years

The Shapotou National Nature Reserve in the Ningxia Hui Autonomous Region is a typical arid region in China. There is an exceptionally serious problem of surface water resource conservation, and dynamic monitoring of surface water with the help of water indices can help to elucidate its change patterns and impact mechanisms. Here, we analysed the characteristics of interannual variation in surface water area in the study area from 1992–2021. The correlation coefficients of the surface water area in the previous year and the contemporaneous water bodies of the Yellow River with the total surface water area (TSWA) were calculated. The results show the following: ① In terms of the classification accuracy of the two methods, water indices and support vector machine classification, water indices are more suitable for water body extraction in the study area. In particular, the three water indices, NDWI, MNDWI and AWEIsh, were more effective, with average overall accuracies of 90.38%, 90.33% and 90.36% over the 30-year period, respectively. ② From the TSWA extraction results from the last 30 years, the TSWA showed an increasing trend with an increase of 368.28 hm2. Among the areas, Tenggeli Lake contributed the most to the increase in TSWA. ③ The highest correlation between the TSWA and the previous year’s TSWA was 0.89, indicating that the better way to protect the water body is to maintain water surface stability year-round. The surface water area of the Yellow River and TSWA also showed a strong correlation, indicating that the rational use of Yellow River water is also an important direction for the future conservation of water resources in the study area.

Wood powder biochar in CdS-WPB-g-C3N4 heterojunction as an electron transfer medium for enhancing photocatalytic performance toward degradation methyl orange

Biochar-based photocatalysts were rarely used in wastewater treatment, as the low efficiency of the electron transfer often limited their applicability. In this work, a novel ternary CdS-WPB-CN heterojunction was constructed for the efficient degradation of methyl orange (MO) under UV and visible light. As a green and low-cost electron transfer medium, wood powder biochar (WPB) plays an important role in rapidly transporting photogenerated electrons from g-C3N4 to CdS, significantly improving photogenerated carriers' separation efficiency. Under the optimal degradation condition (1 g/L photocatalyst dosage and 10 mg/L of initial MO concentration), the degradation efficiency for MO of the ternary CdS-WPB(5%)-CN composite reached 99% within 80 min under visible light irradiation. Moreover, it could completely degrade MO within 60 min under UV irradiation. Besides, the outstanding reusability and stability of the CdS-WPB-CN composite were further verified by five consecutive cycle experiments. The degradation experiment in the actual river water body confirmed the excellent applicability in real wastewater samples. Finally, a mechanism was proposed to explain the photocatalytic degradation of MO. Overall, this work provides important insights into the role of biochar in improving the photocatalytic degradation of organic contaminants.

Impact of artisanal small-scale (gold and diamond) mining activities on the Offin, Oda and Pra rivers in Southern Ghana, West Africa: A scientific response to public concern

The surface water systems of Ghana serve as a major source of drinking water, besides other multi-purpose benefit of hydro-electrical power generation and transportation. Thus, the dependence and benefits from such resources are of national interest. For instance, the Pra river of the South-Western surface water system of Ghana was a major consideration for a projected 5 billion m3 water demand in the year 2020 and “African Water Vision 2025”. In recent times, the colour state of the Pra river and similar surface water bodies of the Offin and Oda rivers has attracted intense public discussion. The prime issue relates to incessant illegal artisanal gold/diamond mining on or along these rivers. In order to assess the state of these rivers, water samples were taken, and analysed at the Council of Scientific and Industrial Research Laboratory (CSIR, Accra-Ghana) to investigate their physico-chemical quality. The research objective was to assess the extent of their water pollution by measuring physico-chemical parameters of turbidity, colour, pH and content of selected metals. A total of 18 preserved bottled samples [(5 from Offin river and 2 boreholes), 5 from Oda river and 5 from Pra river and 1 borehole)] were analysed, and results compared with portable water standards as defined by the WHO and CSIR (GS-175-1) of Ghana.Results on turbidity, colour, mercury and iron from the river and water samples generally exceed WHO or GS-175-1 limit. The Pra river recorded the most alarming result; range for turbidity (2,010 to 2,745 NTU), colour (3,000 to 4,500 Hz), total suspended solutes (2,240 to 2,570 mg/L) and total dissolved solutes (97.80–99.60 mg/L, excluding 319.00 to 25,440 mg/L). The Oda river shows lowest parameter values among the three rivers, as the areas have been dormant from illegal gold mining for 5 years. Current data suggests polluted river bodies and boreholes, and that none of these water resources meets the portable water consumption criteria unless treated prior to usage. As the current state of the water bodies may incur higher cost of water treatment or purification, an integrated water governance under Ghana's Ministry of Water Resource, Work and Housing, and the Minerals Commission and Environmental Protection Agency are recommended for the management of these valuable water resources.

Toponyms: a neglected asset within the water framework and flood directives implementation process; the case study of Greece

Proxy data and qualitative information are important assets in water resources and floods management. In the research, the river water bodies with characteristic toponyms (hydronyms) in Greece that potentially reflect the water’s quality or the occurrence of floods are evaluated in comparison to the European Union’s (EU) Water Framework and Flood Directives implementation process outputs. For doing so, after identifying the river water bodies with characteristic toponyms which form the 10.2% of the Greek water bodies, the toponyms are cross correlated with the water bodies quality status as retrieved by the Directives’ databases to validate the existence of linkages between the names and the quality. Similarly, the significant floods, as derived from the Flood Directive, are spatially allied with the water bodies with characteristic toponyms to ground truth the connection between significant floods and water bodies whose toponyms imply flood prone areas. The research outputs indicate a high degree of correlation both in terms of water quality and floods, meaning that in almost all cases the water body toponym depicts the good or bad quality of the water body or the occurrence of flood events. Moreover, it is established that almost 90% of the water bodies with characteristic names are intermittent and ephemeral ones. The water bodies’ toponyms, hence, are proposed as an auxiliary criterion during the Directives implementation process that could foster increased water quality and flood-related knowledge, especially in intermittent and ephemeral water bodies which are generally lacking observations, and can be applied not only in all EU-Member States’ waters, but also in global scale.

A Comparison of Different Water Indices and Band Downscaling Methods for Water Bodies Mapping from Sentinel-2 Imagery at 10-M Resolution

Satellite-based remote sensing is important for monitoring the spatial distribution of water resources. The water index is currently one of the most widely used water body extraction methods. Based on Sentinel-2 remote sensing image, this study combines area-to-point regression kriging interpolation, bilinear interpolation, and the Gram–Schmidt (GS) pan-sharpening method with the water indices MNDWI, AWEIsh and WI2015 to compare different water body extraction methods. The experimental results showed that all water indices have satisfactory extraction ability, with the kappa coefficient as an accuracy threshold above 0.8. Moreover, the GS downscaling method combined with the WI2015 yielded the best performance. This research demonstrates the efficacy of the WI2015 method to extract water bodies in urban areas and its ability to comprehensively describe river water bodies. The findings indicate that high-resolution band information is particularly important for improving low-resolution band downscaling results and can significantly minimize erroneous water body extraction.

Adsorption behaviour of tetrabromobisphenol A on sediments in Weihe River Basin in Northwest China

Tetrabromobisphenol A (TBBPA) is adsorbed on sediments in river environments, and various environmental factors have distinct effects on its adsorption behaviour. Investigating the adsorption behaviour of TBBPA on the sediments in Weihe River Basin is critical for protecting the water environment and providing a theoretical basis for the prevention and control of brominated flame retardant pollution. In this study, the adsorption behaviour of TBBPA on Weihe River sediment was investigated by conducting batch equilibrium experiments, and the effects of pH, dissolved organic matter, and ionic strength on the adsorption of TBBPA were discussed. The obtained results revealed that rapid adsorption was the main mechanism of the TBBPA kinetic adsorption process. The isothermal adsorption behaviour of TBBPA was well fitted by Freundlich model (R2 99.21%) than Langmuir model (R2 98.59%). The adsorption capacity for TBBPA is 34.13 mg/kg. The thermodynamic results revealed that the adsorption process of TBBPA by the sediment was a spontaneous endothermic reaction. The increase in pH and ionic strength inhibited the adsorption of sediments on TBBPA. With the increase in the humic acid concentration, the adsorption of TBBPA initially increased and subsequently decreased. Synchrotron radiation-Fourier transform infrared spectroscopy indicated that the adsorption mechanism of TBBPA on the surface of sediment was mainly π–π and hydrogen bonds. The obtained results are useful for understanding of TBBPA migration and transformation in river water bodies.

Dissolved organic matter in bovine slaughterhouse wastewater using fluorescence spectroscopy associated with CP/PARAFAC and PCA methods.

In this work, we evaluated the potential application of fluorescence spectroscopy, associated with the canonical polyadic/parallel factor analysis and principal component analysis, to monitor the dissolved organic matter (DOM) generated from a slaughterhouse industry. During the monitoring process, we analyzed the residual water at the entrance and exit sites of the slaughterhouse effluent treatment as well as downstream and upstream the effluent receiving water body of a local river. The results revealed that the fluorescence analysis was able to identify proteins, chlorophylls, and humic substances at the entrance and exit sites of the slaughterhouse treatment plant and humic substances at the river water bodies. Our data also demonstrated that the industrial effluent discharged into the river did not impact the receiving water body quality as determined by the biological and humification indices obtained by fluorescence analysis, which was confirmed by conventional physicochemical analysis. In summary, the present findings indicate that fluorescence spectroscopy, in association with multivariate analysis, can be successfully applied as an analytical tool for evaluating the quality of DOM in slaughterhouse wastewater.

Quantifying the groundwater seepage along a glacier originated river by integrated use of radium isotopes and hydrochemistry

Glaciers, as the core part of the cryosphere, are very sensitive to climate change. As an indicator of glacier changes, the characteristics of glacier-originated rivers have profound significance to global climate change and local water resources. In this paper, the Mingyong River, a glacier-originated river replenished by groundwater, was selected to study the river hydrological cycle characteristics by integrating natural tracer radium isotopes with hydrochemical parameters. The results showed that there were significant differences in radium isotope activities and hydrochemical parameters between groundwater and river water, and the radium activities increased along the river, which reflected the fact that the river was supplied by groundwater seepage. We also found that the activity ratios of 224Ra/228Ra in river and groundwater were less than one unit, which indicated that the groundwater and river water circulated rapidly and that the radioactive equilibrium of short-time radium isotopes had not yet been reached. According to the geochemical behavior of radium in river water body, the mass balance equation of radium was established. 228Ra and 224Ra were used to estimate the groundwater seepage of different segments of the Mingyong River. The results demonstrated that the groundwater seepage fluxes calculated by 224Ra and 228Ra were similar and increased along the river from 123.12 to 657.68 m3 m−1 d−1. Our results have certain significance in revealing the characteristics of the local hydrological cycle and demonstrate that radium isotopes can be used as a tool to estimate the groundwater discharge of rivers in glacial environments.

Variations in the Suspended Sediment Concentration in Mountain-Type Rivers Flowing Into the Sea in the Past 60 years—Taking Nanliu River in Beibu Gulf as an Example

Suspended sediment in the water body of rivers flowing into the sea is of great significance to the accumulation process in river basins and change pattern of landforms. In particular, small and medium rivers entering the sea in mountainous areas exhibit the characteristics of both mountains and streams, and the suspended sediment concentration (SSC) greatly contributes to the formation and evolution of deltas. However, scholars rarely give attention to the factors influencing changes in the SSC in small- and medium-sized mountainous rivers, and few studies have examined SSC changes in small- and medium-sized mountainous rivers. Here, based on daily SSC and flow data obtained at the Bobai Station and Changle Station, the percentile method and regression analysis method are employed to analyse the changes in SSC from the Nanliu River to the Beibu Gulf and possible influencing factors. The main research results indicate that 1) the SSC in river water bodies from 1965 to 2020 generally reveals a downwards trend, with significant annual variations. Specifically, the overall trend can be divided into three stages: 1) the SSC is the highest from 1965 to 1971, and the mean yearly SSC reaches 0.25 kg/m3; 2) the SSC is relatively high from 1972 to 2006, and the mean yearly SSC reaches 0.16 kg/m3; and 3) the SSC is the lowest from 2007 to 2020, and the mean yearly SSC reaches 0.11 kg/m3 2) High values of the SSC are mainly concentrated in the flood season, and low SSC values mostly occur in the dry season. The monthly average SSC in the flood season from April to September and the dry season from October to March exhibits the characteristics of a decrease in the flood season and an increase in the dry season. Moreover, the peak SSC value in the watershed obviously occurs out of sync with the peak flow value. Generally, the former precedes the latter. 3) The curve of the flow rate-sediment ratio is an irregular clockwise rhombus. Moreover, the impact of tropical cyclones, land cover changes, regional GDP per capita, and engineering construction are crucial reasons for the observed variations in the SSC in the Nanliu River Basin. In this paper, the obtained research results provide an important guiding significance for the planning and management of water and sediment resources in the Nanliu River and offer a reference for hydrological planning of other river basins discharging into the sea.

Evaluation of polluted urban river water quality: a case study of the Xunsi River watershed, China.

Urbanization has caused severe negative impacts on intra-urban river water bodies. In this paper, 22 physicochemical parameters were measured at 20 locations in the level period and 29 locations in the wet and dry period using nearby urban area surface water samples from a medium-sized polluted river (a lake-river continuum, i.e., Xunsi River, Qingling River and Tangxun Lake) in the Yangtze River watershed in Wuhan, China. In this study, the environmental quality standards for surface water of China (GB3838-2002) and the WHO drinking water standard (2011) were used as reference standards. After the basic physicochemical parameters were evaluated, the possible sources of pollution in the study area under urban pressure were examined by applying multivariate statistical techniques. The factor analysis method and entropy weighting method identified three critical factors describing the type of surface water pollution in the watershed: (1) pollution from nutrients, mainly nitrogen pollution, (2) trace metals pollution, mainly from Fe and Pb, and (3) organic pollution. Based on multivariate analysis, the weighted arithmetic water quality index (WQI) was used to assess the water quality of each period. The WQI results show that the water near the urban area of the watershed temporally shows light to moderate pollution overall in the level and wet periods, and sever pollution in the dry period. The worst water quality indicating water that is not suitable for any practical use occurs in the dry period. Spatially distributed in clusters and strips visualized in kriging method, the water quality of the lake source and upstream is better than that of the downstream. In addition, Escherichia coli was detected at consistently high levels, and although the river is not a source of drinking water, it could pose a threat to downstream waterworks.