基于流域要素空间关系的水污染溯源研究

为快速准确地实现水质监测断面水质超标时的河流水污染溯源,提出整合现有流域要素,构建水污染溯源的流域要素空间关系模型。该模型以划分为4个等级的河段和汇水单元为基础,建立汇水单元层级与上下游河段的编码关系;再将全流域要素与汇水单元建立空间关联关系,构建5个流域要素空间关系子系统模型;最后各子系统模型集聚组成一个相互协作的流域要素空间关系网络。以敖江流域实时水质监测断面为污染溯源触发点,将各个流域要素空间关系子系统模型直接应用于水污染溯源过程,结果表明,建立的关系模型在实际应用中能最大限度地提供污染源空间分布和结构信息,有效地识别和筛选研究区域的水污染引发源,快速缩小未知污染源搜查范围,提高了水污染溯源搜寻过程的效率和精度。     

FingerPro: an R Package for Tracking the Provenance of Sediment

Soil loss by erosion processes is one of the largest challenges for food production and reservoir siltation around the world. Information on sediment, nutrients and pollutants is required for designing effective control strategies. The estimation of sediment sources is difficult to get using conventional techniques, but sediment fingerprinting is a potentially valuable tool. This procedure intends to develop methods that enable to identify the apportionment of sediment sources from sediment mixtures. We developed a new tool to quantify the provenance of sediments in an agroforest catchment. For the first time, the procedure for the selection of the best combination of tracers was included in the tool package. An unmixing model algorithm is applied to the sediment samples to estimate the contribution of each possible source. The operations are compiled in an R package named FingerPro, which unmixes sediment samples after selecting the optimum set of tracers. An example from a well-studied Mediterranean catchment is included in the package to test the model. The sediment source apportionments are compared with previous results of soil redistributions where ¹³⁷Cs derived rates validate the unmixing results, highlighting the potential of sediment fingerprinting for quantifying the main sediment provenance. Fingerprinting techniques will allow us to better comprehend sediment transport to water ecosystems and reservoirs and its detrimental effect on the quality of the water and aquatic habitats. The FingerPro package provides further understanding of the unmixing procedure through the use of graphical and statistical tools, offering a broader and easier application of the technique.

     

Modelling pathogen fate in stormwaters by a particle-pathogen interaction model using population balances

Stormwater is polluted by various contaminants affecting the quality of receiving water bodies. Pathogens are one of these contaminants, which have a critical effect on water use in rivers. Increasing the retention time of water in stormwater basins can lead to reduced loads of pathogens released to the rivers. In this paper a model describing the behaviour of pathogens in stormwater basins is presented including different fate processes such as decay, adsorption/desorption, settling and solar disinfection. By considering the settling velocity distribution of particles and a layered approach, this model is able to create a light intensity, and particle and pathogen concentration profile along the water depth in the basin. A strong effect of solar disinfection is discerned. The model has been used to evaluate pathogen removal efficiencies in stormwater basins. It includes a population of particle classes characterized by a distribution of settling velocities in order to be able to reproduce stormwater quality and treatment in a realistic way.     

Catchment Phosphorous Losses: An Export Coefficient Modelling Approach with Scenario Analysis for Water Management

This paper presents the development of an export coefficient model to characterise the rates and sources of P export from land to water in four reservoir systems located in a semi-arid rural region in southern of Portugal. The model was developed to enable effective management of these important water resource systems under the EU Water Framework Directive. This is the first time such an approach has been fully adapted for the semi-arid systems typical of Mediterranean Europe. The sources of P loading delivered to each reservoir from its catchment were determined and scenario analysis was undertaken to predict the likely impact of catchment management strategies on the scale of rate of P loading delivered to each water body from its catchment. The results indicate the importance of farming and sewage treatment works/collective septic tanks discharges as the main contributors to the total diffuse and point source P loading delivered to the reservoirs, respectively. A reduction in the total P loading for all study areas would require control of farming practices and more efficient removal of P from human wastes prior to discharge to surface waters. The scenario analysis indicates a strategy based solely on reducing the agricultural P surplus may result in only a slow improvement in water quality, which would be unlikely to support the generation of good ecological status in reservoirs. The model application indicates that a reduction of P-inputs to the reservoirs should first focus on reducing P loading from sewage effluent discharges through the introduction of tertiary treatment (P-stripping) in all major residential areas. The fully calibrated export coefficient modelling approach transferred well to semi-arid regions, with the only significant limitation being the availability of suitable input data to drive the model. Further studies using this approach in semi-arid catchments are now needed to increase the knowledge of nutrient export behaviours in semi-arid regions.     

ENVIRONMENTAL STRESSORS AFFLICTING TAILWATER STREAM REACHES ACROSS THE UNITED STATES

The tailwater is the reach of a stream immediately below an impoundment that is hydrologically, physicochemically and biologically altered by the presence and operation of a dam. The overall goal of this study was to gain a nationwide awareness of the issues afflicting tailwater reaches in the United States. Specific objectives included the following: (i) estimate the percentage of reservoirs that support tailwater reaches with environmental conditions suitable for fish assemblages throughout the year, (ii) identify and quantify major sources of environmental stress in those tailwaters that do support fish assemblages and (iii) identify environmental features of tailwater reaches that determine prevalence of key fish taxa. Data were collected through an online survey of fishery managers. Relative to objective 1, 42% of the 1306 reservoirs included in this study had tailwater reaches with sufficient flow to support a fish assemblage throughout the year. The surface area of the reservoir and catchment most strongly delineated reservoirs maintaining tailwater reaches with or without sufficient flow to support a fish assemblage throughout the year. Relative to objective 2, major sources of environmental stress generally reflected flow variables, followed by water quality variables. Relative to objective 3, zoogeography was the primary factor discriminating fish taxa in tailwaters, followed by a wide range of flow and water quality variables. Results for objectives 1–3 varied greatly among nine geographic regions distributed throughout the continental United States. Our results provide a large‐scale view of the effects of reservoirs on tailwater reaches and may help guide research and management needs. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

Identification and Quantification of Uncertainties in a Hydrodynamic River Model Using Expert Opinions

Hydrodynamic river models are applied to design and evaluate measures for purposes such as safety against flooding. The modelling of river processes involves numerous uncertainties, resulting in uncertain model outcomes. Knowledge of the type and magnitude of uncertainties is crucial for a meaningful interpretation of the model results and the usefulness of results in decision making processes. The aim of this study is to identify the sources of uncertainty that contribute most to the uncertainties in the model outcomes and quantify their contribution to the uncertainty in the model outcomes. Experts have been selected based on an objective Pedigree analysis. The selected experts are asked to quantify the most important uncertainties for two situations: (1) the computation of design water levels and (2) the computation of the hydraulic effect of a change in the river bed. For the computation of the design water level, the uncertainties are dominated by the sources that do not change between the calibration and the prediction. The experts state that the upstream discharge and the empirical roughness equation for the main channel have the largest influence on the uncertainty in the modeled water levels. For effect studies, the floodplain bathymetry, weir formulation and discretization of floodplain topography contribute most to the uncertainties in model outcomes. Finally, the contribution of the uncertainties to the model outcomes show that the uncertainties have a significant effect on the predicted water levels, especially under design conditions.     

A total phosphorus budget for the Lake of the Woods and the Rainy River catchment

The overall goal of this study was to quantify the major and minor sources and losses of total phosphorus (TP) to the Lake of the Woods (LOW), summarized as a nutrient budget. This research was initiated in response to degradation in lake water quality, including elevated TP concentrations and increased cyanobacterial blooms, which has resulted in LOW's classification as an “Impaired Waterbody” in Minnesota. The whole-lake LOW TP budget shows that tributary inflow is largely dominated by a single source, the Rainy River, draining 79% of the LOW catchment by area. Currently, there is only a small TP contribution from shoreline residential developments (6 t; ~ 1%) at a whole-lake scale, relative to the large TP loads from atmospheric deposition (95 ± 55 t; 13%) and the Rainy River (568 ± 186 t; 75%). Overall, the annual TP load to LOW was ~ 754 t with ~ 54% TP retained within the lake. The nutrient budget for the Rainy River catchment revealed that contributions from point sources along the river constitute the largest anthropogenic TP source to the Rainy River and eventually to LOW. Historical load calculations along the Rainy River show that this load has been significantly reduced since the 1970s, and presently just over 100 t of P enters LOW from anthropogenic point sources. These TP budgets provide insights into the major sources of TP influencing the overall LOW water quality and with future refinement may provide a greater understanding of linkages between TP loading and spatial and temporal water quality changes in the LOW.     

Role of Land Use and Seasonal Factors in Water Quality Degradations

Surface water and groundwater are the most important water sources in the natural environment. Land use and seasonal factors play an important role in influencing the quality of these water sources. An in-depth understanding of the role of these two influential factors can help to implement an effective catchment management strategy for the protection of these water sources. This paper discusses the outcomes of an extensive research study which investigated the role of land use and seasonal factors on surface water and groundwater pollution in a mixed land use coastal catchment. The study confirmed that the influence exerted on the water environment by seasonal factors is secondary to that of land use. Furthermore, the influence of land use and seasonal factors on surface water and groundwater quality varies with the pollutant species. This highlights the need to specifically take into consideration the targeted pollutants and the key influential factors for the effective protection of vulnerable receiving water environments.     

基于正态云-模糊可变耦合模型的水环境质量评价

水环境质量评价作为了解和分析水环境现状及问题的基本内容,是河流规划、治理和管理的重要依据。针对水环境质量评价存在的模糊性、随机性和最大隶属度不严谨等问题,提出正态云-模糊可变评价耦合模型。模型对模糊边界问题进行定量化处理,确定隶属函数和识别水质级别,并采用最小相对熵原理计算组合权重。运用该模型评价秦淮河流域2016年的水环境,评价结果同单因子指数评价法、模糊综合评价法和云模型评价法进行对比。结果表明:正态云-模糊可变耦合模型更加合理、有效可靠;模型级别特征值H分析表明秦淮河上游和秦淮新河段汛期水环境大部分优于非汛期,但同时也表现出城镇工业、生活等污染特征;内、外秦淮河段,汛期河岸的污染物排入河流中,故汛期水环境劣于非汛期,表现出典型的城市生活及餐饮等"三产"污水污染特征。研究方法和结果对地区和流域的水环境质量评价和研究具有一定的借鉴和指导意义。     

Duration curve analysis for the assessment of pathogen loading from diffuse sources.

Pathogen level of surface waters has received great attention for protecting public health. In this study, total coliform, fecal coliform and Escherichia coli concentrations were monitored as the pathogen indicator organisms at six monitoring stations in the Geum River, Korea. Rainfall runoff from two agricultural-forestry watersheds was analyzed for their microbial aspect as well. Total coliform concentration of the Geum River showed high correlation with the flow rate. To estimate total coliform loading on the Geum River in probability scale, the duration curve method was applied. In addition, a standard duration curve reflecting the water quality criteria was constructed to determine water quality compliance. Under the assumption of linearity between flow rate and total coliform concentration of the Geum River, total coliform duration curve revealed that total coliform concentrations exceed the desired criteria mainly due to pollutants from diffuse sources.     

Bacteriological Quality of Rainwater in Roof and Ground Catchment Systems in Botswana

ABSTRACT

Bacteriological analyses were conducted on water samples from 13 roof tanks and 8 ground catchment tanks in Botswana in 1983. The results show that rainwater collected from corrugated iron roofs and stored in covered tanks is of high quality compared with traditional water sources and could provide a safe drinking water supply. The results for the ground catchment tanks, however, indicated that the water posed a serious health hazard. This is significant since several hundred ground tanks are already being used to provide water for other things besides human consumption. Since more ground tanks are planned both in Botswana and elsewhere in Africa the fencing of the catchment area and the use of simple sand and charcoal filters are recommended as the most practical means of insuring improved water quality in ground tanks.     

Estimation of diffuse and point source microbial pollution in the ribble catchment discharging to bathing waters in the north west of England.

Achieving compliance with the mandatory standards of the 1976 Bathing Water Directive (76/160/EEC) is required at all U.K. identified bathing waters. In recent years, the Fylde coast has been an area of significant investments in 'point source' control, which have not proven, in isolation, to satisfactorily achieve compliance with the mandatory, let alone the guide, levels of water quality in the Directive. The potential impact of riverine sources of pollution was first confirmed after a study in 1997. The completion of sewerage system enhancements offered the potential for the study of faecal indicator delivery from upstream sources comprising both point sources and diffuse agricultural sources. A research project to define these elements commenced in 2001. Initially, a desk study reported here, estimated the principal infrastructure contributions within the Ribble catchment. A second phase of this investigation has involved acquisition of empirical water quality and hydrological data from the catchment during the 2002 bathing season. These data have been used further to calibrate the 'budgets' and 'delivery' modelling and these data are still being analysed. This paper reports the initial desk study approach to faecal indicator budget estimation using available data from the sewerage infrastructure and catchment sources of faecal indicators.     

Biofilms in an urban water distribution system: measurement of biofilm biomass, pathogens and pathogen persistence within the Greater Stockholm Area, Sweden.

Distribution pipe biofilms can provide sites for the concentration of a wide range of microbial pathogens, thereby acting as a potential source of continual microbial exposure and furthermore can affect the aesthetic quality of water. In a joint project between Stockholm Water, the MISTRA "Sustainable Urban Water" program, the Swedish Institute for Infectious Disease Control and the Royal Technical University, Stockholm, the aim of the current study was to investigate biofilms formed in an urban water distribution system, and quantify the impact of such biofilms on potential pathogen accumulation and persistence within the Greater Stockholm Area, Sweden. When used for primary disinfection, ultra-violet (UV) treatment had no measurable influence on biofilm formation within the distribution system when compared to conventional chlorination. Biofilms produced within a model pilot-plant were found to be representative to those that had formed within the larger municipal water distribution system, demonstrating the applicability of the novel pilot-plant for future studies. Polystyrene microspheres (1.0 microm) and Salmonella bacteriophages demonstrated their ability to accumulate and persist within the model pilot-plant system, where the means of primary disinfection (UV-treatment, chlorination) had no influence on such phenomena. With the exception of aeromonads, potential pathogens and faecal indicators could not be detected within biofilms from the Stockholm water distribution system. Results from this investigation may provide information for water treatment and distribution management strategies, and fill key data gaps that presently hinder the refinement of microbial risk models.     

Contribution of agricultural and non-agricultural use of pesticides to the environmental impact on aquatic life in regional surface water systems.

By means of a modelling tool an analysis was made of the local variation in the use of pesticides in the province of Utrecht in The Netherlands, and the potential environmental impact of pesticide emissions on the aquatic ecosystems. The aim of this study was to identify and quantify the major sources of pesticide use and environmental impact, taking the regional variation of pesticide use into account. The analysis was targeted at different levels: detailed (individual active substances, individual agricultural crops, civil land-use types, hydrological catchment basins) and globally covering agricultural use, non-agricultural use (some civil sectors) and recreational shipping. The results can be used for the (re)design of environmental monitoring programmes of pesticides in surface waters and for the development of region based policies towards sustainable pesticide use. The analysis tool that was developed is considered to be applicable for other regions as well.     

滨江流域GPS降水预报系统的研究与实现

 利用试验区建立的GPS水汽监测网获得的近乎实时的水汽数据,采用模块开发和系统集成方式,研制了流域GPS降水预报系统。介绍了系统的体系结构、主要功能、运行情况及开发的关键技术。叙述了流域降水预报的各种预报方法,并建立了基于遗传算法的降水预报神经网络模型(GA-BP网络模型)。结果表明,GPS水汽可为降水预报提高精度;GA-BP网络是一种精度较高的降水预报模型,可提高预测精度,增长有效预见期。该系统能根据流域GPS观测数据、高空数据、卫星云图,数值产品等数据,实现不同数据源的信息处理和不同时效的降水预报制作,为洪水预警预报和防洪决策服务。     

缺资料流域水污染物总量分配方法研究

流域水污染物总量分配对流域水环境管理至关重要。但在缺资料流域,污染负荷的计算分析往往因水文资料匮乏而变得非常困难。本文以赣江袁河流域为例,在划分流域控制单元的基础上,利用SWAT模型对袁河流量进行模拟,再结合LDC(负荷历时曲线)法,实现了袁河流域分区(控制单元)、分期(丰水期、平水期、枯水期)、分类(点源和非点源)和分级(不同水质目标)的总量分配方案。结果表明,SWAT径流模拟精度较为满意,可以为LDC法提供控制单元内部的流量;新余工业区及其下游的保留区是袁河污染物超标最为严重的区域,超标污染物主要以点源为主,其中新余工业区削减量最大。研究结果说明SWAT模型结合LDC方法可以较好地应用于资料匮乏流域的水污染物总量分配。     

Integrated Surface–Subsurface Modeling of Fuxianhu Lake Catchment, Southwest China

This paper describes an integrated surface–subsurface modeling study of the Fuxianhu Lake catchment (southwest China). Pollution threats to this important water resource have led to the need to evaluate transport pathways and the overall water balance of the catchment. Catchment inputs to the lake include river inflows, direct overland flow and groundwater discharge, which are incorporated into a mathematical model of the system. Surface runoff and groundwater recharge are estimated using a parsimonious soil–vegetation modeling approach, while groundwater flow is based on the MODFLOW-2005 code. Overland flow and stream discharge are coupled to the groundwater regime through the soil layer and are routed through the catchment to account for surface water flow pathways. The model is tested using the V-catchment benchmark problem and is compared to existing models to demonstrate accuracy and capability. Application of the model to the Fuxianhu catchment provides for the first-order approximation of the average catchment water balance, which comprises such components as evapotranspiration losses (37% of rainfall), surface runoff to the lake (37% of rainfall), and groundwater discharge to the lake (8% of rainfall), amongst others. The computationally efficient approach to surface–subsurface modeling adopted in this investigation presents as an alternative to more complex methods, and allows for the rapid assessment of flow pathways at the catchment scale. An erratum to this article can be found at     

Simulation of an irrigation tank for modernization

A digital simulation model of a tank irrigation system is used to quantify the effects of adopting various modernization scenarios available for improved water management. Out of ten different modernization scenarios considered, the scenario incorporating modifications to the sill level of the sluices, and in the conveyance efficiency with improved catchment, yields the greatest water savings when compared with the baseline conditions. The policy options therefore suggest that lining of the main canals is one of the modernization options which offers a fairly large scope. There is also potential for substantially augmenting the carrying capacity of the tank by desilting it.     

Nitrogen fluxes on catchment scale: the influence of hydrological aspects.

In two catchment areas with altogether eight subcatchments characterising different site-specific situations the interaction between anthropogenic activities (e.g. agriculture, nutrition and waste water management), nitrogen emissions and in stream loads as well as concentrations were studied in detail. Groundwater is the most important pathway for nitrogen inputs into surface waters. Denitrification in the soil/subsurface/groundwater system controls the amount of this input to a high extent. Key factors influencing this process are organic carbon availability, geology, precipitation and groundwater recharge rates as well as residence time in groundwater. The MONERIS emission model is a useful tool to quantify these relationships on (sub-)catchment scale. Areas where concentrations in groundwater (e.g. nitrate) tend to be higher due to little dilution with water and might be problematic in respect to limit values for drinking water, are much less relevant in respect to the loads transported to river systems and receiving seas, than regions with high precipitation. In cases with high water availability mainly high loads transported downstream and finally to the receiving sea are a considerable problem. Within a region mainly areas close to river systems contribute to nitrogen discharges to the river system because of the short residence times of the groundwater from these areas and--related to this--a lower influence of denitrification in the groundwater.     

Development of water quality management strategies for the proposed Isikli Reservoir

A two-dimensional laterally averaged hydrodynamic and water quality model (CE-QUAL-W2) is used to simulate the water quality behavior in the proposed Istkli Reservoir of the Ankara Water Supply System to determine appropriate strategies for the management of water quality.Isiklt application of the model is used to demonstrate the potential water quality degradation patterns in the reservoir under different pollution loads. The results of the modeling study are compared with the drinking water quality standards currently effective in Turkey to formulate various water quality management strategies for the reservoir and its catchment area. In addition, various treatment options are evaluated considering the existing treatment system of Ankara City.Based on the findings of this study, treatment or interception of wastewaters originating from the existing pollution sources around the reservoir area are introduced as the major infrastructural control techniques. Further, establishment of protection zones around the reservoir and relocating the possible pollution sources to a point downstream of the dam axis are found to be the most applicable administrative control methods for water quality preservation in the proposed reservoir.