Phosphorus and nitrogen in the waters of the El-Kabir River watershed in Syria and Lebanon

In order to assess the quality of the waters of the El‐Kabir River, which forms the border between Lebanon and Syria, water samples were collected for phosphorus (P) and nitrogen analyses at 39 sample stations in the river watershed (18 in Syria, 21 in Lebanon). These samples were collected on the main stem and three major tributaries (Nahr al‐Arous and Nahr Nasrive in Syria, Chadra River in Lebanon). Three major springs also were sampled. The sampling was carried out in September 2001, and January, April and August 2002. Nutrient analyses were carried out on samples taken in September 2001, January and April 2002 in Syria, and in September 2001 and August 2002 in Lebanon. The P concentrations were extremely high throughout the watershed, as were the ammonia‐nitrogen and nitrate‐nitrogen concentrations, indicating extensive pollution. Although the nitrite‐nitrogen concentration was relatively low, it is at the upper end of what might be considered normal, thereby perhaps being indicative of some anthropogenic sources. The spring waters were found to be polluted by nutrients. The nutrient sources contributing to the river pollution were mainly from piped, direct sewage discharges from the many settlements throughout the basin. These were supplemented by diffuse sources directly from agricultural fertilizer use and from the indiscriminate disposal of solid wastes into the river and on the stream banks and lands adjacent to the roads of the watershed.     

Environmental management of the waters of the El-Kabir River and the associated Akkar watershed

The Akkar watershed of the El‐Kabir River forms the northern boundary of Lebanon with Syria and drains into the Eastern Mediterranean Sea. This paper endeavours to provide a management plan tailored to the issues and needs of the Akkar watershed. It is not designed as a simplistic workbook of procedures but as a series of broad, thematic recommendations addressing the environmental problems identified by technical studies and interaction with the inhabitants of the watershed. It outlines a three‐phase (short, medium and long‐term) approach to address public health and water sustainability in the context of an enduring management system. In all phases, a set of underlying principles are utilized which incorporate a watershed approach, collaboration and cooperation, sustainability, a balance between water quantity and quality, equity and public involvement.     

Perchlorate in environmental waters of the Laurentian Great Lakes watershed: Evidence for uneven loading

A database of nearly 500 analyses of perchlorate in water samples from the Laurentian Great Lakes (LGL) watershed is presented, including samples from streams, from the Great Lakes and their connecting waters, with a special emphasis on Lake Erie. These data were assessed to test an earlier hypothesis that loading of perchlorate to the LGL watershed is relatively uniform. Higher perchlorate concentrations in streams in more developed and urban areas appear to indicate higher rates of loading from anthropogenic sources in these areas. Variable perchlorate concentrations in samples from Lake Erie indicate transient (un-mixed) conditions, and suggest loss by microbial degradation, focused in the central basin of that lake. Interpretation of the data included estimation of annual loading by streams in various sub-watersheds, and simulations (steady state and transient state) of the mass balance of perchlorate in the Great Lakes. The results suggest uneven loading from atmospheric deposition and other sources.     

Tritium in Laurentian Great Lakes surface waters

A basin-wide water quality survey for the radionuclide tritium during 2017 and 2019 provides an overview of levels in Great Lakes surface waters. All data, together with those from similar basin-wide surveys since the early 1990s, are included in the Supplemental Material. Values of tritium are lowest in Lake Superior and are highest within a region of northwestern Lake Ontario, as well as locally near a known source in Lake Huron. Twenty-year trends show declines in all of the lakes, and this is consistent with the decline in fallout from past nuclear weapons testing, the major source of tritium to the lakes. Longer-term trends, developed using values from the literature, demonstrate a marked overall reduction in tritium values since maxima in the late 1960s, with a slowing rate of decline in the most recent decade. As atmospheric fallout is reduced, the relative importance of other sources is increasing. Known releases, primarily from nuclear generating stations using heavy water, could therefore drive any future changes in Great Lakes tritium levels.     

Bacterial indicators of faecal pollution in the waters of the El-Kabir River and Akkar watershed in Syria and Lebanon

Water samples for bacterial analyses were taken, when possible, at 41 sites in Lebanon and Syria in the El‐Kabir River watershed. Samples were analysed for total coliform (TC), faecal coliform (FC) and faecal streptococcus. The Lebanese samples also were analysed for the presence of sulphate‐reducing bacteria. The TC and FC concentrations were extremely high throughout the watershed, rendering the water unfit for any human uses. The origin of the bacteria is the untreated sewage waste from the numerous settlements situated throughout the watershed. This primary origin is supported by high ratios of FC/faecal streptococcus, although impacts from animal wastes also were observed. The bacterial levels were higher in summer than in winter, indicating a high winter river flow that dilutes a relatively constant source of human sewage discharged to the system. Spring waters also exhibited elevated levels of bacteria, implicating surface land use and waste disposal practices upstream of the springs. The data clearly shows that human health is at a high risk and that strategies for improving water quality and protecting spring water must be expeditiously implemented.     

我国地表水体粪大肠菌群污染现状分析

基于20世纪80年代以来公开发表的文献,调研了我国地表水体(河流、湖泊、水库、近海海域)粪大肠菌群的含量,对粪大肠菌群含量的时空分布及变化进行了分析,并对影响这种分布特性的因素进行了系统的分析和讨论。结果表明:我国地表水体粪大肠菌群含量普遍较高,受到较为严重的粪便污染,其中河流水系含量最高,湖泊、海域次之,水库最低;粪大肠菌群含量的年际和年内波动都较大,年内丰水期含量高于枯水期含量;粪大肠菌群含量的空间分布特性为南北无明显差异,东部水域含量高于西部水域含量,下游水体含量高于上游水体含量,近岸水体含量高于远岸水体含量,人为干扰严重的水体含量高于干扰轻的水体含量。降雨径流对粪大肠菌群含量的时空变化存在非常显著的影响,同时水体有机物含量、富营养化程度、盐度及温度等物理化学特性也影响着粪大肠菌群在水体中的分布。     

Impacts of water surface area of watershed on design flood简

In order to analyze the impact of the water surface area of a watershed on the design flood, the watershed was classified into a land watershed and a water surface watershed for flood flow calculation at the same time interval. Then, the design flood of the whole watershed was obtained by adding the two flood flows together. Using this method, we calculated design floods with different water surface areas of three reservoirs and analyzed the impact of water surface area on the flood volume and peak flow. The results indicate that larger water surface areas lead to greater impacts on the flood volume and peak flow. For the same watershed area, the impact of water surface area on the flood volume and peak flow is positively proportional to the flood frequency, i.e., the higher the frequency, the greater the impact becomes.     

Assessment of sediment contamination from pollutant discharge in surface waters

Based on theoretical considerations, the pollutant trapping efficiency (PTE) of a river section was introduced to assess sediment contamination from pollutant discharge. Under simplified assumptions, PTE can be calculated by the sedimentation of suspended particulate matter (SPM), the inflowing concentration of SPM and the solidwater partition coefficient K_d. Regarding a more complex field case, a one-dimensional flow and transport model was applied to a lock-regulated section of the Neckar River, Germany. Long-term simulations (1950–1994) were carried out (a) to analyse the temporal development of sediment contamination and (b) to quantify the dependence of the PTE of cadmium on K_d and the Damkoehler number, characterizing the time scale of the adsorption process with respect to the water residence time in the regarded river section. Sediment contamination by Cd shows a strong response to the decrease of Cd emission in the past. In the case of rapid adsorption, sediment contamination increases non-linearly with rising partition coefficient. This agrees qualitatively with the formula derived from theoretical considerations. At the measured kinetic adsorption rates, chemical equilibrium of solid-water partitioning is reached at low to moderate discharge, and sediment contamination in the river reservoir is determined by the hydraulic trapping of the polluted SPM.     

降水和下垫面对流域径流量影响的定量研究

定量分析降水和下垫面变化对径流的影响,对流域水资源规划管理具有重要的意义。以北京市漫水河流域为研究对象,对漫水河1956-2016年年降水量、天然径流量的变化趋势及突变性进行了分析,以径流变异前1956-1979时间段为基准期,建立降水径流双累积曲线关系,识别与基准期相比不同时期降水和下垫面条件变化对天然径流的贡献率。结果表明:2000年以后流域内耗水、水利工程调蓄水等人类活动的直接影响有所减少,与1956-1979年基准期相比,1990-1999年降水量的影响程度大于下垫面,为63. 9%; 1980-1989、2000-2009、2010-2016年3个时期下垫面对径流量减少的影响程度均大于降水,降水量和下垫面对径流量减少的贡献率分别为44. 9%和55. 1%、47. 9%和52. 1%、44. 5%和55. 5%。     

河流水质与流域人类活动之间的关系

河流水质状况受流域内的自然和人类活动这两大类因素的影响，其中，人类活动往往是导致河流水质恶化的主要因素，即水环境质量与流域内的各类人类活动密切相关。考虑到我国在这方面研究的还比较少，远不能满足水资源保护与水污染控制的迫切需要，本文从国外发表的大量研究成果中，选择介绍河流水质与几种典型的流域人类活动因素(人口、农事活动、土地利用结构等)之间的定量关系，并指出了需要进一步研究的问题，为我国的研究与实践提供借鉴。     

Towards good ecological status of surface waters in Europe--interpretation and harmonisation of the concept.

The Water Framework Directive (WFD) is a new legislative framework to manage, use, protect, and restore surface water and groundwater resources and coastal waters in the European Union (EU). The aim is to ensure sustainable water management and to reach good water quality by 2015. The assessment of the ecological status and setting of the practical management goals require several steps. The process has started with the characterisation of the river basins including identification of surface water bodies and types, and identification of significant anthropogenic pressures and impacts. The water bodies will be classified in five quality classes (high, good, moderate, poor, bad) based on the Ecological Quality Ratio, which is a ratio between reference conditions and measured status of the biological quality elements. The normative criteria for high, good and moderate ecological status described in the WFD need to be made operational because those will be used to set the practical quality targets for surface water management. National ecological assessment systems and classifications will be harmonised through the WFD intercalibration exercise in order to ensure an equal level of ambition in achieving good surface waters status all over Europe.     

Evaluation of three unit hydrograph models to predict the surface runoff from a Canadian watershed

The predictability of unit hydrograph (UH) models that are based on the concepts of land morphology and isochrones to generate direct runoff hydrograph (DRH) were evaluated in this paper. The intention of this study was to evaluate the models for accurate runoff prediction from ungauged watershed using the ArcGIS^® tool. Three models such as exponential distributed geomorphologic instantaneous unit hydrograph (ED-GIUH) model, GIUH based Clark model, and spatially distributed unit hydrograph (SDUH) model, were used to generate the DRHs for the St. Esprit watershed, Quebec, Canada. Predictability of these models was evaluated by comparing the generated DRHs versus the observed DRH at the watershed outlet. The model input data, including natural drainage network and Horton's morphological parameters (e.g. isochrone and instantaneous unit hydrograph), were prepared using a watershed morphological estimation tool (WMET) on ArcGIS^® platform. The isochrone feature class was generated in ArcGIS^® using the time of concentration concepts for overland and channel flow and the instantaneous unit hydrograph was generated using the Clark's reservoir routing and S-hydrograph methods. An accounting procedure was used to estimate UH and DRHs from rainfall events of the watershed. The variable slope method and phi-index method were used for base flow separation and rainfall excess estimation, respectively. It was revealed that the ED-GIUH models performed better for prediction of DRHs for short duration (≤6 h) storm events more accurately (prediction error as low as 4.6–22.8%) for the study watershed, than the GIUH and SDUH models. Thus, facilitated by using ArcGIS^®, the ED-GIUH model could be used as a potential tool to predict DRHs for ungauged watersheds that have similar geomorphology as that of the St. Esprit watershed.     

A physicochemical characterization of the waters of the El-Kabir River and major tributaries in Syria and Lebanon

Thirty‐nine sampling sites were selected in the El‐Kabir River watershed, including 18 in Syria and 21 in Lebanon. Three major tributaries, the Nahr al‐Arous and the Nahr Nasrive in Syria, and the Chadra River in Lebanon, were included in the site selection, together with Wadi el‐Aatchane and Wadi Khaled. Instrumental measurements for temperature, specific conductivity (Sp. Cond.), dissolved oxygen (DO) and pH were taken directly in the water at each site visit. Measurements were taken in both countries in May 2001, January, April and August 2002, and there was an additional sampling in Lebanon during September 2001. The interpretation of the data led to some specific conclusions on the conditions in the watershed. The waters of the El‐Kabir River are derived almost exclusively from ground water, with many significant springs functioning throughout the year. The water that flows rapidly through the system is well‐mixed and consistent in its major characteristics. The DO concentration > 5 mg L^?1, averaging 8.53 mg L^?1 (three DO values < 5 mg L^?1 were observed, all at the same spring). Some variability in water character was observed for Sp. Cond.; these differences could be related to the spring‐source waters originating in limestone or basaltic terrain. Furthermore, an increase in Sp. Cond. in the lower reaches of the river might be related to salinization, resulting from surface water and near‐surface ground water withdrawals for anthropogenic use, particularly irrigation.     

Comparison of the components of the planktonic food web in three large rivers (Rhine,Moselle and Saar)

The dynamics of phyto‐, bacterio‐, proto‐ and metazooplankton were investigated for a period of 22 months fortnightly from March 1999 until December 2000 in the rivers Moselle, Saar and Rhine. Plankton abundances reached the lowest values in the Rhine and the highest in the Saar. Protozoa and not the much more studied metazoa clearly dominate the zooplankton not only by number but also by biomass by about 90%. We show that the plankton biomass in each of the rivers is the result of the interplay of the grazing by benthic predators and of the human induced factors such as river morphology, water residence time and nutrient load. Furthermore, we compare our study with the planktonic food web of three other large European rivers. The comparison between all studies revealed a general rise of the absolute mean biomass of all heterotrophic planktonic food web components (bacteria, protozoa, metazoa) parallel to an increase of the algal biomass of the river. For the rivers Rhine, Moselle and Saar, the average biomass of all investigated plankton groups was very low compared to the values obtained in the rivers Meuse, Loire and Elbe. The relative importance of organisms of the microbial food web increased with a decrease of the algal biomass or organic carbon content, respectively, in each of the rivers. We postulate that with a sinking nutrient level in the Rhine, the microbial food web components will become even more important within the plankton than they already are. Copyright © 2008 John Wiley & Sons, Ltd.     

High levels of pelagic plastic pollution within the surface waters of Lakes Erie and Ontario

During 2012 to 2014 five expeditions collected surface water samples for plastic pollution analysis representing the first data within Lake Ontario and the first multi-year dataset for Lake Erie. Lake Ontario had the highest abundances of any Great Lake to date with an average of over 230,000 particles/km². Though having a considerable smaller average of ~45,000 particles/km², Lake Erie remains second only to Lake Ontario based on studies to date and averaged across all samples and years. The high levels of pelagic plastic pollution is likely owing to their position as the last two lakes in the Laurentian Great Lakes ecosystem, as well as the prominence of population centers along their shorelines. As with previous studies, most particles were found within the smallest size classification (0.355–0.999 mm; 73%), with fragments (63%) and pellets (26%) forming the dominant morphologies. The minor contribution of fibers/lines (4%) is consistent with previous Great Lakes studies, though not with studies within other environmental compartments (e.g., sediment, fish, atmospheric). This could be due to the negative buoyancy of polymeric fibrous materials, a hypothesis consistent with the dominance of the less dense polymers polyethylene (46%) and polypropylene (43%) (based on FTIR analysis). For the first time, the multiyear Lake Erie samples were compared to modeled plastic distributions and found to fit reasonably well. Using the sample data to calibrate the model we estimate that there are 475 million plastic particles, with a total mass of 6.45 metric tons, floating on the surface of Lake Erie alone.     

Distribution of dioxins in surface soils and river-mouth sediments and their relevance to watershed properties.

The dioxins toxic equivalent (TEQ) concentration in surface soils, river sediments and river-mouth sediments was measured by the CALUX assay in the Yasu and Ado River basins around Lake Biwa, Japan. In order to examine the distribution of dioxins in each watershed, we evaluated and compared the correlation between the dioxins TEQ concentration and the solid characteristics (i.e. organic carbon content and particle size distribution) of all samples. In both basins, the dioxins TEQ concentration in forest soil correspondingly showed a very good linear relationship to organic carbon content. On the other hand, the dioxins TEQ concentration in paddy field was significantly high, although organic carbon content was relatively low. Generally, the smaller particles have the higher dioxins TEQ concentrations in surface soils, and river sediments were composed of very coarse particles and had relatively low dioxins TEQ concentration. Therefore, we expected high dioxins TEQ concentration in river-mouth sediment, which was, however, not the case. Although the dioxins TEQ concentration in river-mouth sediments is low, the degree of dioxins pollution was different in each basin. The difference was considered to come from the difference of watershed properties including land use, river-slope, dam construction as well as the surface soil pollution.     

System design and treatment efficiency of a surface flow constructed wetland receiving runoff impacted stream water

This study reported the efficiency of a free water surface flow constructed wetland (CW) system that receives runoff impacted stream water from a forested and agricultural watershed. Investigations were conducted to examine the potential effect of hydraulic fluctuations on the CW as a result of storm events and the changes in water quality along the flow path of the CW. Based on the results, the incoming pollutant concentrations were increased during storm events and greater at the near end of the storm than at the initial time of storm. A similar trend was observed to the concentrations exiting the CW due to the wetland being a relatively small percentage of the watershed (<0.1%) that allowed delays in runoff time during storm events. The concentrations of most pollutants were significantly reduced (p < 0.05) except for nitrate (p = 0.5). Overall, this study suggests that the design of the system could feasibly function for the retention of most pollutants during storm events as the actual water quality of the outflow was significantly better by 21-71% than the inflow and the levels of pollutants were reduced to appreciable levels.     

连云港海域悬沙和表层沉积物交换研究

采用粒度谱计算方法分析连云港及邻近海域悬沙和表层沉积物交换特征,为徐圩防波堤口门布置和连云港港航道回淤研究提供理论支撑。连云港港主航道和徐圩航道5 m等深线以外的区域悬沙和表层沉积物交换率为0.1~0.2,表明航道回淤强度将处于较低水平,对今后航道维护有利;5 m等深线以内区域的交换率为0.3~0.4,悬沙落淤对航道回淤有一定贡献,表明该航道段回淤量相对较大,计算结果与实测航道回淤强度分布特征基本一致。灌河口沙嘴正常天气条件下交换率小于0.2,说明悬沙落淤对沙嘴的影响较小;5 m等深线以内破波带水域交换率大于0.5,表明悬沙和表层沉积物交换频繁。连云港港及邻近海域悬沙和表层沉积物交换主要为粒径小于62 μm的细颗粒组分。分析结果表明,为减少泥沙回淤对徐圩港区港池正常运行的影响,兴建防浪挡沙堤并将堤头布置在破波带之外十分必要。     

Electron-optical characterization of nano- and micro-particles in raw and treated waters: an overview.

State-of-the-art information is presented on the analysis, by transmission electron microscopy (TEM), of aquatic colloidal particles in the size range of 3 to 500 nm least dimension, with a focus on nanoparticles (1-100 nm). Case studies include selections from both natural waters and waters undergoing treatment. The "species" of nano-particles receiving the greatest attention are: humic substances, polysaccharide fibrils, hydrous iron oxides, viruses, clay minerals, refractory cell debris, and heavy metal agglomerates on biological surfaces. Artifacts and how to both detect and minimize them are outlined. Correlative use of TEM with other imaging techniques is emphasized, along with associated spectroscopy. Noted is the potential of computerized image analysis for quantifying colloids on a "per colloid species" basis, using water samples centrifuged onto electron microscope grids.     

Management issues in the Lake Victoria watershed

Lake Victoria is the largest lake in Africa (68 800 km²) and is the eighth largest lake in the world by volume. The three East African countries of Tanzania, Uganda and Kenya share Lake Victoria and its resources. The total annual catch of fish from the lake ranges between 400 × 10⁶ kg and 500 × 10⁶ kg, bringing these riparian countries a combined annual income of approximately US$250 000–500 000 from exports alone. Approximately 30 million people live in the riparian region and the catchment, with about 2 million of these depending directly or indirectly on fishing activities. Tragically, Lake Victoria’s extremely diverse fauna was decimated in only 30 years following the introduction of non‐native Nile perch in the early 1960s. An estimated 200 endemic cichlid species became extinct. Dramatic increases in overfishing, pollution from various sources, effects of noxious water weeds and other associated problems threaten the sustainability of the lake’s resources and the economies of the riparian governments and peoples. Regulations governing Lake Victoria’s resources are different in each country. The laws concerning treatment of effluents from point sources in the three countries are not harmonized, neither are implementation or enforcement provisions. The governments of Kenya, Uganda and Tanzania have begun to put in place regional mechanisms to address the lake’s many problems including the creation of a permanent regional international institution through the establishment of the Lake Victoria Fisheries Organization (LVFO). A strategic vision document and action plans have been developed. Efforts are being made at local, national and regional levels to control the water hyacinth, including manual pulling, mechanical harvesting and introduction of weevils that weaken hyacinth root systems. To address the problem of overfishing, fishermen committees at landing beaches have been put in place. Each country has committed to take all necessary measures including legislation to implement the decisions of the LVFO governing bodies. All three countries have agreed to adopt and enforce legislation and regulations prohibiting the introduction of non‐indigenous species to the lake and to enforce existing regulations regarding fisheries. A Global Environment Facility project which provides funding to the Lake Victoria Fisheries Organization addresses land use management, catchment forestation, fisheries research and management, water hyacinth control, industrial effluent treatment and municipal waste treatment.