River Surface Water Research Articles

Hydrochemical Characteristics and Controlling Factors of Surface Water in Upper Nujiang River, Qinghai-Tibet Plateau

Rivers play an essential role in the global matter transport and hydrogeochemical cycle. Hydrogeochemical research is significant to developing and protecting water resources in the Qinghai-Tibet Plateau and its lower reaches. This study aimed to identify the hydrochemical characteristics and controlling factors of Daqu River and Gaqu River in Dingqing County, two tributaries of the upper Nujiang River. This study used spatial analysis, trilinear diagram analysis, and ion ratio analysis of hydrochemical indexes to investigate the hydrochemical characteristics and controlling factors. Results show that Ca2+ and Mg2+, and HCO3− and SO42− are the main cations and anions of these two rivers. HCO3·SO4-Mg·Ca and HCO3·SO4-Ca·Mg are the primary hydrochemical types for the surface water of Daqu and Gaqu Rivers, respectively. The influence of atmospheric precipitation and anthropogenic activities is weak. The carbonated water–rock reaction is the main Ca2+, Mg2+, and HCO3− source, and hot springs act as the primary source of SO42− and supplements Ca2+, Mg2+, and HCO3−. Mg2+ from magnesite dissolution exists in the Daqu River basin. Weak reverse cation exchange occurs in both rivers. Daqu River receives more low-mineralized glacier meltwater along the flow, whereas Gaqu River receives more high-mineralized hot spring water.

Social Value Assessment and Spatial Expression of National Park Ecosystems Based on Residents’ Perceptions

Social values of ecosystem services originate from human perceptions of ecosystem services and are defined as non-market values perceived by ecosystem stakeholders. Although it is widely recognized that the information of social value can provide assistance to stakeholders and decision makers in environmental management, this issue has received far less attention. This article uses the Public Participation Geographic Information System (PPGIS) method to analyze the assessment of social values of national park ecosystem services by residents with different environmental values and their relationship with surrounding natural resource conditions. According to the preference of the interviewed residents, it was found that the four most important types of social value are biodiversity value, aesthetic value, economic value, and recreation and wellness value. In terms of spatial distribution, the hot spots of social values show a pattern of “two cores and multiple centers”. The “two cores” are the Gutianshan National Nature Reserve and Qianjiangyuan National Forest Park, which are located at the north and south ends of the national park; the “multiple centers” include Kukeng, Xikeng, Xiachuan, Gaotiankeng villages in Changhong Township and Longkeng Village in the Hetian Township. By analyzing the relationship between the four social value types with higher preference and the resource environment (land use and elevation), the article found that social values are closely related to scenic spots, river water surface, reservoir water surface, forested land, tea plantations, and villages, and that they are mostly distributed in the range of 400 m to 600 m above sea level. The distribution of social values in the ecocentric subgroup is larger, covering almost the entire national park area. The transition of the value index is smoother, while the distribution of social values in the anthropocentric subgroup is relatively concentrated in one area.

Flavobacterium ammonificans sp. nov. and Flavobacterium ammoniigenes sp. nov., ammonifying bacteria isolated from surface river water.

Three aerobic, Gram-stain-negative, non-motile, rod-shaped bacteria, designated as strains SHINM13T, GENT5T and GENT11 were isolated from surface river water (Saitama Prefecture, Japan). SHINM13T and GENT11 were positive for catalase, whereas GENT5T was negative. Phylogenetic analyses based on the 16S rRNA gene (1341 bp) or 40 marker gene (34,513 bp) sequences revealed that the strains formed distinct phylogenetic lineages within the genus Flavobacterium. The three strains shared 99.3-99.6 % 16S rRNA gene sequence similarity among each other. The average nucleotide identity by orthology (OrthoANI) and digital DNA-DNA hybridization (dDDH) values between strains SHINM13T and GENT11 were 96.56 and 82.1 %, respectively, and those between SHINM13T and GENT5T were 83.46 % and 52.9 %, respectively. The major cellular fatty acids were C15 : 1ω6c, iso-C15 : 0, iso-C15 : 1G, anteiso-C15 : 0 and iso-C15 : 0 3-OH. The major polar lipid was phosphatidylethanolamine. SHINM13T and GENT5T contained menaquinone-6 (MK-6) as the predominant respiratory quinone, and their DNA G+C contents were 34.4 and 35.1 mol%, respectively. Genome sequencing of the three isolates revealed a genome size of 2.26-2.40 Mbp. Furthermore, all three isolates converted dissolved organic nitrogen to ammonium during cell growth. On the basis of the results of phenotypic and phylogenetic analyses, strains SHINM13T and GENT11 and GENT5T represent two distinct novel species in the genus Flavobacterium, for which the names Flavobacterium ammonificans sp. nov. (type strain SHINM13T =JCM 34684T =NCIMB 15379T) and Flavobacterium ammoniigenes sp. nov. (type strain GENT5T =JCM 32249T=NCIMB 15380T) are proposed.

Time-Varying Functional Principal Components for Non-Stationary EpCO_2 in Freshwater Systems

Outgassing of carbon dioxide (CO_2) from river surface waters, estimated using partial pressure of dissolved CO_2, has recently been considered an important component of the global carbon budget. However, little is still known about the high-frequency dynamics of CO_2 emissions in small-order rivers and streams. To analyse such highly dynamic systems, we propose a time-varying functional principal components analysis (FPCA) for non-stationary functional time series (FTS). This time-varying FPCA is performed in the frequency domain to investigate how the variability and auto-covariance structures in a FTS change over time. This methodology, and the associated proposed inference, enables investigation of the changes over time in the variability structure of the diurnal profiles of the partial pressure of CO_2 and identification of the drivers of those changes. By means of a simulation study, the performance of the time-varying dynamic FPCs is investigated under different scenarios of complete and incomplete FTS. Although the time-varying dynamic FPCA has been applied here to study the daily processes of consuming and producing CO_2 in a small catchment of the river Dee in Scotland, this methodology can be applied more generally to any dynamic time series.Supplementary materials accompanying this paper appear online.

Characteristics and origin of clogging-functional bacteria during managed aquifer recharge: A laboratory study

Owing to serious influences on well performance, bacteria-induced clogging has become a dilemma for managed aquifer recharge (MAR). During MAR, surface river water is inoculated into aquifer and mixed with groundwater. Therefore, the clogging-functional bacteria may originate from the river water or the groundwater. However, the origin of the clogging-functional bacteria in the aquifer has not yet been well understood. This study conducted a series of laboratory-scale column experiments involving different recharge modes (using river water, groundwater) to simulate the processes of bacteria-induced clogging and used the high-throughput sequencing technology, aiming to elucidate the community characteristics and the origin of the clogging-functional bacteria involved in MAR bioclogging. Analyses of the bacterial-community characteristics showed significant differences between the river water and groundwater. The bacterial-community characteristics of the clogging aquifer in the different recharge modes were similar to each other and have common genera, namely, Acinetobacter, Brevundimonas, Exiguobacterium, Porphyrobacter, Cloacibacterium, and Sphingobium, which suggests that MAR activity could promote bacterial communities to become identical during surface water infiltration into aquifers, despite differences in the bacterial communities present in the subsurface- and surface systems. This knowledge will assist greatly in targeted treatment and prophylaxis of clogging-functional bacteria during managed aquifer recharge.

Spatial Distribution and Influential Factors of Nutrients in Rivers of a Typical Mountainous City: A Case Study of the Qingshuixi River in Chongqing

Surface water pollution seriously restricts the development of the city and results in the citizens yearning for a better life. Mountainous cities have their own characteristics in surface water environment and pollution compared with those of plain cities due to their unique topography. In August and October 2019, surface water and sediments were collected in a typical river (Qingshuixi River) in the main urban area of Chongqing. These samples were analyzed for nutrients such as carbon, nitrogen, and phosphorus as well as other basic physicochemical indicators. The results showed that the surface water of the Qingshuixi River was inferior to Category V at present, and it was also at a serious pollution level according to the comprehensive pollution index evaluation system. Among all the water quality indices, NH4+ and TP showed the most serious pollution. The tributaries of the Qingshuixi River exhibited higher surface water quality than that of the main stream, and the water quality during the rainfall season was better than that during the non-rainy season. Pollution sources, tailwater/tributary inflow, and river self-purification capacity determined the spatial distribution of nutrients in the surface water of the mainstream of the Qingshuixi River. Point sources such as the direct discharge of source sewage and pollution overflow in the middle and lower reaches were the most important sources of surface water pollution in the mainstream of the Qingshuixi River. Non-point source pollution had a limited impact on water quality. The "sink" or "source" role transformation of river sediments would occur under different water volume conditions in the river, reflecting the complexity of endogenous pollution. Surface water quality of the main stream showed a gradual improvement tendency along the downstream due to the dilution of the tail water/tributary inflow and the increased self-purification capability of the surface water in the mountainous rivers due to the increased DO content. To summarize, this study suggests that the water environment of the Qingshuixi River should be improved in comprehensive ways, which might be reducing the input of point source pollution by the deployment of the municipal pipe network in key areas, upgrading the sewage treatment plants to decrease pollutant concentrations or fluxes or channel dredging at the reaches with low DO content, etc.

Distribution Dynamics of Phthalate Esters in Surface Water and Sediment of the Middle-Lower Hanjiang River, China.

Phthalate esters (PAEs) are endocrine-disrupting chemicals that pose potential risks to human health. Water and sediments are crucial carriers and storage media for the migration and transformation of PAEs. In this study, six congeners of PAEs were measured in water and sediment samples to elucidate their spatial distribution, congener profiles, and ecological risks in the middle-lower Hanjiang River during the wet and dry seasons. The concentration of the Σ6PAEs ranged from 592 to 2.75 × 103 ng/L with an average of 1.47 × 103 ng/L in surface water, while the concentration of the Σ6PAEs ranged from 1.12 × 103 to 6.61 × 103 ng/g with an average of 2.69 × 103 ng/g in sediments. In general, PAE concentrations were ranked as sediment > water, and dry season > wet season. DEHP and DBP were the dominant PAEs in the middle-lower Hanjiang River in surface water and sediments. SPSS analysis showed that dissolved organic carbon (DOC) in surface water was significantly correlated with the concentration of DBP, DEHP, and the ∑6PAEs, while organic matter (OM) was significantly correlated with the concentration of the ∑6PAEs in sediments. The concentrations of PAEs were irregularly distributed and varied significantly in surface water and sediments. Compared with other regions at home and abroad, the pollution levels of surface water and sediments in the middle-lower Hanjiang River were relatively low and not enough to have a negative impact on the local water’s ecological environment. However, the supervision of land-based discharge should still be strengthened.

Spatial and temporal dynamics of microbial community composition and factors influencing the surface water and sediments of urban rivers

The temporal and spatial characteristics of urban river bacterial communities help us understand the feedback mechanism of bacteria to changes in the aquatic environment. The Fuhe River plays an important role in determining the water ecological environment of Baiyangdian Lake. 16S rRNA gene sequencing was used to study the microbial distribution characteristics in the Fuhe River in different seasons. The results showed that some environmental factors of the surface water (ammonia nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP)) were different on the spatial and temporal scales. Moreover, there were no seasonal differences in the contents of TN, TP, total organic carbon (TOC), or heavy metals in the sediments. The distributions of Cyanobacteria, Actinomycetes and Firmicutes in the water and Actinomycetes and Planctomycetes in the sediments differed significantly among seasons (P < 0.05). There were significant spatial differences in bacteria in the surface water, with the highest abundance of Proteobacteria recorded in the river along with the highest nutrient concentration, while the abundance of Bacteroidetes was higher in the upstream than the downstream. Microbial communities in the water were most sensitive to temperature (T) and the TP concentration (P < 0.01). Moreover, differences in the bacterial community were better explained by the content of heavy metals in the sediments than by the chemical characteristics. A PICRUSt metabolic inference analysis showed that the effect of high summer temperatures on the enzyme action led to an increase in the abundances of the metabolic-related genes of the river microorganisms.

Along‐Orbit Analysis of GRACE Follow‐On Inter‐Satellite Laser Ranging Measurements for Sub‐Monthly Surface Mass Variations

AbstractWe examined the sensitivity of GRACE Follow‐On (GRACE‐FO) laser ranging interferometer (LRI) measurements to sub‐monthly time‐variable gravity (TVG) signals caused by transient, high‐frequency mass changes in the Earth system. GRACE‐FO LRI provides complementary inter‐satellite ranging measurements with higher precision over a wider range of frequencies than the baseline K‐band microwave ranging system. The common approach for studying mass variation relies on the inverted TVG or mascon solutions over a period of, for example, one month or 10 days which are adversely affected by temporal aliasing and/or smoothing. In this article, we present the alternative along‐orbit analysis methodology in terms of line‐of‐sight gravity difference (LGD) to fully exploit the higher precision LRI measurements for examination of sub‐monthly mass changes. The discrepancy between “instantaneous” LGD LRI observations and monthly‐mean LGD (from Level‐2 data) at satellite altitude indicates the sub‐monthly gravitational variability not captured by monthly‐mean solutions. In conjunction with the satellite ocean altimetry observations, high‐frequency non‐tidal atmosphere and ocean models, and hydrology models, we show that the LGD LRI observations detect the high‐frequency oceanic mass variability in the Argentine Basin and the Gulf of Carpentaria, and sub‐monthly variations in surface (river) water in the Amazon Basin. We demonstrate the benefits gained from repeat ground track analysis of GRACE‐FO LRI data in the case of the Amazon surface water flow. The along‐orbit analysis methodology based on LGD LRI time series presented here is especially suitable for quantifying temporal and spatial evolution of extreme, rapidly changing mass variations.

Characteristics of Ions Composition and Chemical Weathering of Tributary in the Three Gorges Reservoir Region: The Perspective of Stratified Water Sample from Xiaojiang River

River water chemistry offers information on watershed weathering and responds to the global carbon cycle. Watershed weathering processes and water chemistry in stratified water are still unclear in Xiaojiang River, as a major tributary of the Three Gorges Reservoir (TGR) which is the largest reservoir in the world. Major ions of river water at different depths were measured to reveal the ionic composition and chemical weathering properties by principal component analysis and stoichiometry in Xiaojiang River. Ca2+−HCO3− dominated the hydrochemical facies of river. Surface river water had the lowest total dissolved solid (146 mg/L) compared to other layers of water. According to principal component analysis, the major ions were divided into two principal components. PC1 was the weathering end-member of rocks, including the main ions except K+ and NO3–N, and PC2 may be the mixed end-member of atmospheric input and anthropogenic input. From stoichiometry, carbonate weathering dominated the cationic composition, with a contribution ratio of 56.7%, whereas atmospheric input (15.2%) and silicates weathering (13.9%) had similar extent of contribution. Compared with other major tributaries of TGR, Xiaojiang had more intense chemical weathering processes. The weathering rates of carbonates and silicates were 19.33 ± 0.68 ton/km2/year and 3.56 ± 0.58 ton/km2/year, respectively. Sulfuric acid as a proton may have participated less in the weathering processes of Xiaojiang River. The CO2 consumption budgets for silicates and carbonates weathering were 0.8 ± 0.2 × 109 mol/year and 2.8 ± 0.2 × 109 mol/year, respectively. These results enrich the watershed weathering information of TGR tributaries and provide data support for understanding the global carbon cycle.

Long-term spatiotemporal changes of surface water and its influencing factors in the mainstream of Han River, China

Study regionHan River mainstream, China. Study focusHuman activities and climate change are synergistically impacting on the spatiotemporal features of Han River surface water, which affects the ecological environment evolution and economic development of the basin. However, the long-term changes of the area and spatial characteristics of Han River surface water have not been well quantified for lack of sufficient data and data processing powers. The study produced the annual surface water products of Han River mainstream from 1986 to 2020 based on Google Earth Engine and Landsat images, and then analyzed the long-term spatiotemporal dynamics of surface water and the influence of climatic factor and water conservancy projects construction. New hydrological insights for the regionDuring the past 35 years, the surface water area of Han River mainstream has shown a fluctuating upward trend overall, and the dynamic changes have obvious regional and phased differences. Precipitation is the main climatic factor affecting the surface water area changes. With precipitation changes and the implementation of water conservancy projects in Han River, the surface water area has increased significantly and many reaches have gradually widened in upstream, while the surface water area has slowly decreased and many reaches have gradually narrowed in mid-downstream. The latest information about the spatiotemporal dynamics of Han River surface water provided by the research can be used for the optimal allocation and management of the river’s water resources.

Assessment of heavy metals in surface water, sediment and macrozoobenthos in inland rivers: a case study of the Heihe River, Northwest China.

Long-term retention and accumulation of heavy metals in surface water and sediment pose a great threat to the sustainable development of aquatic ecosystems and human health. In this research, macrozoobenthos, and surface water and sediment heavy metal (Mn, Cr, Cu, Ni, Pb, Zn, Cd, and As) samples were collected from 23 sites in the upper and middle reaches of the Heihe River in the summers of2019-2020. The interrelationships between heavy metals and macrozoobenthos were analyzed by Pearson correlation analysis and redundancy analysis (RDA), and the contamination level and potential ecological risk of the heavy metals in surface water and sediments were assessed by comprehensive pollution index (WQI), single potential ecological risk index ([Formula: see text]), and sediment quality guideline-quotient (SQG-Q), respectively. The results showed that the level of heavy metal pollution in the surface water of the Heihe River was extremely low, but the contents of Mn and Pb exceeded the third class of surface water environmental quality standards (GB 3838-2002). The spatial distribution of heavy metals in surface sediments were significantly different, and the average concentration of 8 heavy metals exceeded the background values of Gansu Province. Meanwhile, the pollutionlevel of heavy metals in surface sediments was high pollution, and the ecological risk level was moderate risk. Combining [Formula: see text] and SQG-Q evaluations showed that Cd, Ni, and Cr were the main ecological risk factors. In addition, the distribution coefficients of Cr and Cd were low, indicating that Cr and Cd were easily released from the surface sediments, causing secondary pollution. In terms of the source of the heavy metals, Cu, As, Zn, Cr, and Ni mainly came from industrial and agricultural wastewaters, Pb was from the mining industry and natural sources, and Mn and Cd mainly came from tailings and their landfill leachate. Basommatophora and Araneae can be used as potential indicator organisms for heavy metal pollution in surface water, and Basommatophora, Coleoptera, Hemiptera, and Araneae can be used as indicator species for heavy metal pollution in surface sediments. The study showed that macroinvertebrate community characteristics had a sensitive response to heavy metals in the surface waters and sediments of the Heihe River, which can be used to evaluate the pollution status of heavy metals in inland rivers.

Application of an Optimization/Simulation Model for the Real-Time Flood Operation of River-Reservoir Systems with One- and Two-Dimensional Unsteady Flow Modeling

An application is presented of a new methodology for the real-time operations of river-reservoir systems. The methodology is based upon an optimization/simulation modeling approach that interfaces optimization with a one and/or two-dimensional unsteady flow simulation model (U.S. Army Corps of Engineers HEC-RAS). The approach also includes a model for short-term rainfall forecasting, and the U.S. Army Corps of Engineers HEC-HMS model for rainfall-runoff modeling. Both short-term forecasted rainfall in addition to gaged streamflow data and/or NEXRAD (Next-Generation Radar) can be implemented in the modeling approach. The optimization solution methodology is based upon a genetic algorithm implemented through MATLAB. The application is based upon the May 2010 flood event on the Cumberland River system in the USA, during which releases from Old Hickory dam caused major flooding in the downstream area of Nashville, TN, USA, and allowed the dam to be placed in an emergency operational situation. One of the major features of the modeling effort and the application presented was to investigate the use of different unsteady flow modeling approaches available in the HEC-RAS, including one-dimensional (1D), two-dimensional (2D), and the combined (1D/2D) approach. One of the major results of the application was to investigate the use the different unsteady flow approaches in the modeling approach. The 2D unsteady flow modeling, based upon the diffusion wave approach, was found to be superior for the application to the Cumberland River system. The model application successfully determined real-time operations that would have maintained the flood water surface elevations at the downstream control point in Nashville below the 100-year return period river water surface and maintaining the gate openings at the Old Hickory Dam from reaching an emergency operational situation, which could have caused major losses at the dam.

ВЗАИМОСВЯЗЬ КОНЦЕНТРАЦИИ МАРГАНЦА В ПИТЬЕВОЙ ВОДЕ И БИОСРЕДАХ У КОРЕННОГО И НЕКОРЕННОГО НАСЕЛЕНИЯ ХАНТЫ-МАНСИЙСКОГО АВТОНОМНОГО ОКРУГА

The concentration of Mn in the surface waters of rivers, lakes, tributaries, etc. (n = 103) and tap water (n = 124) of the cities of the Khanty-Mansiysk Autonomous Okrug was determined by atomic absorption spectrometry, as well as by AES-ICP and MS-ICP methods. its content in the hair of the Khanty, who use surface water as drinking water, and residents of the cities of Khanty-Mansi Autonomous Okrug, who use tap water. An excess of the Mn concentration by 1.8 times relative to the MPC in surface waters and the norm in tap water (p-0.001) was established. A signifi cantly higher concentration of the element was found in the hair of the Khanty compared to the hair of non-indigenous residents of the Khanty-Mansi Autonomous Okrug (p &lt; 0.001).

Chemical composition of the surface water in the Ob River

Chemical composition of the surface water in the Ob River

Basicity of titanium-based coagulants matters in the treatment of low-turbidity water

Basicity is an intrinsic factor of coagulants that plays important roles in turbidity removal. However, the effects of basicity on the coagulation performance of titanium (Ti) coagulants remain unclear. This knowledge gap is mainly due to the lack of highly polymerized Ti coagulants. In this study, we fabricated a series of Ti-based coagulants with basicity values in the range of 0–93% and evaluated their coagulation performance with simulated and real waters of low-turbidity. A positive correlation was observed between the basicity of the Ti coagulants and the coagulation performance, i.e., higher basicity led to higher turbidity removal, larger floc size, and faster settling rate. For the two titanium xerogel coagulants (TXC) of similar chemical structures, the one with a higher basicity (TXC-93%) worked better than the one of a lower basicity (TXC-78%). The advantage brought from the difference in basicity is of great significance in the purification of low-turbidity water. For the treatment of a surface river water, the required dosage of TXC-93% was about 1/2 to 1/3 of those of titanium tetrachloride (TiCl4) and polytitanium tetrachloride (PTC-21%), and was comparable to that of a high-quality commercialized polyaluminum chloride (PAC-72%). The results here provide a useful technical guidance for the mass production and application of Ti coagulants.

Calibrating 1D hydrodynamic river models in the absence of cross-section geometry using satellite observations of water surface elevation and river width

Abstract. Hydrodynamic modeling has been increasingly used to simulate water surface elevation which is important for flood prediction and risk assessment. Scarcity and inaccessibility of in situ bathymetric information have hindered hydrodynamic model development at continental-to-global scales. Therefore, river cross-section geometry is commonly approximated by highly simplified generic shapes. Hydrodynamic river models require both bed geometry and roughness as input parameters. Simultaneous calibration of shape parameters and roughness is difficult, because often there are trade-offs between them. Instead of parameterizing cross-section geometry and hydraulic roughness separately, this study introduces a parameterization of 1D hydrodynamic models by combining cross-section geometry and roughness into one conveyance parameter. Flow area and conveyance are expressed as power laws of flow depth, and they are found to be linearly related in log–log space at reach scale. Data from a wide range of river systems show that the linearity approximation is globally applicable. Because the two are expressed as power laws of flow depth, no further assumptions about channel geometry are needed. Therefore, the hydraulic inversion approach allows for calibrating flow area and conveyance curves in the absence of direct observations of bathymetry and hydraulic roughness. The feasibility and performance of the hydraulic inversion workflow are illustrated using satellite observations of river width and water surface elevation in the Songhua river, China. Results show that this approach is able to reproduce water level dynamics with root-mean-square error values of 0.44 and 0.50 m at two gauging stations, which is comparable to that achieved using a standard calibration approach. In summary, this study puts forward an alternative method to parameterize and calibrate river models using satellite observations of river width and water surface elevation.

Lacustrine, wastewater, interstitial and fluvial water quality in the Southern Lake Baikal region.

The coastal area of the southern Lake Baikal with the population over 35,000 people remains an attractive spot for both tourists and local residents. Despite high anthropogenic impact, a detailed assessment of water quality in this area has not been performed so far. Here, we performed a comprehensive evaluation of the quality of the surface, bottom and interstitial water in rivers, lacustrine water and wastewater in the southern Lake Baikal region. We analyzed 37 samples for the presence of fecal enterococci, Escherichia coli and assessed their hydrochemical parameters: concentrations of nutrients (nitrate-N, nitrite-N, ammonium-N and phosphate-P), dissolved oxygen and amount of ions (HCO3- + SO42- + Cl- + Ca2+ + Mg2+ + Na+ + K+). In addition, the temperature, pH and electrical conductivity were also measured. We found that multiple areas around South Baikal suffer from microbiological and hydrochemical pollution. We conclude that ecological situation in this area requires immediate attention from local authorities, more efficient wastewater management systems should be constructed in the settlements. We also conclude that interstitial waters from the lake's splash zone represent an effective and sensitive indicator of sanitary-microbiological and hydrochemical pollution and their analysis can be included in the standard protocol of water quality assessment for all types of water bodies.

Applicability of Difference in Oxygen-18 and Deuterium of Water Sources and Isotopic Hydrograph Separation in a Bamboo Catchment during Different Rainfall Types

Typhoon storm and plum rain are two typical rainfall types in the lower regions of the Yangtze River Basin, which frequently cause flood disasters in China. New information in stable water isotopes offers the opportunity to advance understanding of runoff mechanisms and water source dynamics in response to these two typical rainfall types. We intensively monitored two representative rainfall events in a small bamboo forestry watershed in 2016. Results showed that precipitation isotopic variations during the event were generally larger than those of other monitored compartments (including throughfall, surface overland water, groundwater and river water) and also larger for the plum rain than for the typhoon event (δ18O varied in 5.2‰ and 3.7‰, respectively). Importantly, the differences of isotopic temporal variation between rainfall and throughfall showed significant impacts on the two-component hydrograph separation for both rainfall types (e.g., if not considered, the pre-event water fractions were 26.6% and 15.3% higher for the typhoon and plum rain events, respectively). Furthermore, we evaluated the role of soil water on the three-component isotopic hydrograph separation model; results revealed that soil water accounted for 10.9% and 28.3% of the total discharge in typhoon and plum rain events, respectively. This underpins the important role of soil water dynamics during the rainy season in this humid region.

Evaluating Fecal Indicator and Pathogen Relationships in Sewage Impacted Surface Waters to Blend with Reclaimed Water for Potable Reuse in North Carolina.

Surface waters used for drinking water supply often receive upstream wastewater effluent inputs, resulting in de facto wastewater reuse for drinking water and recreation. As populations grow, demands on water supplies increase. As this trend continues, it creates the need to understand the risks associated with such reuse. In North Carolina, potable reuse has been proposed as a combination of at least 80% surface water with up to 20% tertiary-treated, dual-disinfected, reclaimed wastewater, which is then stored for 5 days and further treated using conventional drinking water treatment methods. The state of North Carolina has set standards for both intake surface water and for the reclaimed water produced by wastewater utilities, using indicator microorganisms to measure compliance. The goal of this study was to quantify fecal indicator microorganisms, specifically E. coli, coliphages, and C. perfringens as well as key pathogens, specifically Salmonella spp. bacteria, adenoviruses, noroviruses, and the protozoan parasites Cryptosporidium and Giardia, in two types of water representing potential candidates for potable reuse in North Carolina, (1) run of river surface water and (2) sewage-impacted surface waters, with the purpose of determining if there are predictive relationships between these two microorganism groups that support microbial indicator reliability.