Sustainable Water Quality Management Research Articles

Role of humic substances as refractory organic matter in sustainable water quality assessment and management

AbstractIn northern China, river water originating from or flowing through forests often contains large amounts of oxygen-consuming organic substances, mainly humic substances. These substances are stable and not easily biodegradable, resulting in very high detection values of chemical oxygen demand. However, under natural conditions, the dissolved oxygen demand is not as high. Using experimental values to evaluate river water quality and the impact of human activities on water quality is thus unscientific and does not meet national development goals. In this study, the potential sources of high-concentration chemical oxygen demand in river water in two areas exposed to virtually no anthropogenic activities and strongly affected by humic substances, were analysed. The chemical oxygen demand contributed by humic substances (COD-HSs) was quantified using three methods. The results of water quality monitoring in 2017 and 2018 revealed that the chemical oxygen demand concentrations (5–44 mg/L) predominantly exceeded the standard (15 mg/L). The study results suggest that COD-HSs should be considered separately for objective evaluation and management of water quality, particularly in areas that are seriously affected by COD-HSs, to provide a scientific basis for formulating sustainable water quality management policies.

Big Data, Knowledge Mapping for Sustainable Development: A Water Quality Index Case Study

Water quality assessment is an increasingly important area in environmental study. Assessment of water quality can be a process include multiple factors which can causing influence on water quality. Researchers have developed many evaluation indices In order to display the results of water quality evaluation more intuitively. Water quality index has been the important fields in sustainable water quality management. This research based on the papers published of 20 years from web of science, analyzed the data by using CiteSpace 5.0. The result shows the direction, frontiers and hotspots of water quality index. Research from institutes, research keywords, word frequency, quoted literature and Subjects. The result shows in view of the world, India, China, US, Brazil and Iran are major countries. From the hotspots and frontiers of research, key words such like water quality management, drinking water quality are the main research hotspots and frontiers of social network in the contamination of water and water quality problem in China and India. this study provide a method for scientists to keep up with the situation of the study on water quality management., and puts forward suggestions for the further research on sustainable water quality index.

Groundwater suitability zonation with synchronized GIS and MCDM approach for urban and peri-urban phreatic aquifer ensemble of southern India

ABSTRACTThe integrated application of Geographic Information System (GIS) and Multi Criteria Decision Making (MCDM) technique is employed for groundwater (GW) suitability zonation in the phreatic coastal aquifer of two differently urbanized clusters in the south west coast of India. The normalized weights in accordance with the WHO and BIS standards were obtained using the MCDM technique-Analytical Network Process integrated with the spatially interpolated GW quality data and performed overlay analysis using spatial analysis tool, ArcGIS-10. The Mann-Whitney U test confirmed the significant (P ≤ 0.05) spatial variation between urban and peri-urban GW quality variables. The groundwater quality index divided the study area into four zones as highly suitable – 60%, suitable –24%, moderately suitable and unsuitable – 16% regions. The study endowed a new platform for the integration of field data and geospatial techniques for sustainable urban water quality management.

Sustainable Management of Reservoir Water Quality and Quantity Through Reservoir Operational Strategy and Watershed Control Strategies

Water quality impairment is a serious health concern for reservoirs; two strategies were used to control reservoir outflow quality: (1) control of reservoir inflows with implementation of structural best management practices (BMPs) at the watershed, and (2) management of reservoir outflows by reservoir operational strategy. To assess the effectiveness of two strategies on reservoir water quality, an extension of the Sustainability Index (SI) for water quality was defined. Additionally, a quantity-based SI for supplying of downstream water demands was defined. So il and water assessment tool was linked to a reservoir simulation model (CE-QUAL-W2), and coupled with multi-objective particle swarm optimization algorithm. The proposed model was applied in four different scenarios on Alavian reservoir and its watershed, in Iran, during a 6-year time horizon. Four BMPs, named detention ponds, filter strips, parallel terraces, and grade stabilization structures, were used. The results indicated that application of the proposed approach provides the best set of solutions for decision makers to manage outflow quality and quantity. Whenever the watershed management strategy is not possible/practical, the reservoir operational strategy in selective withdrawal scheme would improve reservoir outflow quality by up to 77%. On the other hand, when the reservoir downstream water demand satisfaction is necessary, the watershed management strategy, or selective withdrawal scheme would be improved when the reservoir outflow dissolved oxygen concentration SI by up to 30 and 52%, respectively. Among the applied BMPs, filter strip had more effect on reducing nutrient loads and it was the most chosen BMP.

Multi-date trends in groundwater pollution from pit latrines

Abstract This paper provides a multi-date review of trends in groundwater pollution from pit latrine sanitation structures using global, regional and South African cases. The paper focuses on three parameters which are microorganisms, nitrate and phosphorus, which are aligned with the challenge of waterborne diseases, and generally linked to poor water quality, and inadequate sanitation and hygiene. Poor sanitation and hygiene open up transmission routes for ingestion of faecal matter, which as at 2018 continue to pose risks of diarrhoea, opportunistic infections, and consequent malnutrition. These challenges currently account for approximately 1.7 million deaths annually, of which more than 90% are in developing countries, which have low sanitation coverage. While pit toilets are the generally preferred form of sanitation technology for developing countries, most provide evidence of the interconnectedness between the structures and groundwater pollution. The mechanism of pollution is generally indicated to be seepage of polluted pit latrine leachate into groundwater. This specific type of microbial and chemical routing from toilets into the environment increases the prevalence of diseases. These diseases usually result in high mortality for developing countries. Therefore, this review has highlighted the need to minimize pollution of groundwater from pit latrines, thereby contributing towards sustainable water quality management.

Water Recycling via Aquifers for Sustainable Urban Water Quality Management: Current Status, Challenges and Opportunities

Managed aquifer recharge (MAR) is used worldwide in urban environments to replenish groundwater to provide a secure and sustainable supply of potable and non-potable water. It relies on natural treatment processes within aquifers (i.e., filtration, sorption, and degradation), and in some cases involves infiltration through the unsaturated zone to polish the given source water, e.g., treated wastewater, stormwater, or rainwater, to the desired quality prior to reuse. Whilst MAR in its early forms has occurred for millennia, large-scale schemes to replenish groundwater with advanced treated reclaimed water have come to the fore in cities such as Perth, Western Australia, Monterey, California, and Changwon, South Korea, as water managers consider provision for projected population growth in a drying climate. An additional bonus for implementing MAR in coastal aquifers is assisting in the prevention of seawater intrusion. This review begins with the rationale for large-scale MAR schemes in an Australian urban context, reflecting on the current status; describes the unique benefits of several common MAR types; and provides examples from around the world. It then explores several scientific challenges, ranging from quantifying aquifer removal for various groundwater contaminants to assessing risks to human health and the environment, and avoiding adverse outcomes from biogeochemical changes induced by aquifer storage. Scientific developments in the areas of water quality assessments, which include molecular detection methods for microbial pathogens and high resolution analytical chemistry methods for detecting trace chemicals, give unprecedented insight into the “polishing” offered by natural treatment. This provides opportunities for setting of compliance targets for mitigating risks to human health and maintaining high performance MAR schemes.

Solute Geochemistry and Multivariate Analysis of Water Quality in the Guohua Phosphorite Mine, Guizhou Province, China

Water plays a critical role in securing the mine production and domestic consumption in mining areas. This research was carried out to assess the water quality status and to identify the hydrochemical processes contributing to the dissolved constituents of the water in the Guohua phosphorite mine, Guizhou Province, China. Multivariate statistical techniques and correlation analysis were employed to gain a better understanding of the hydrogeochemical processes, and water quality for domestic and irrigation purposes was also assessed. The results indicate that groundwater and surface water quality in the phosphorite mine area is currently excellent with low concentrations of major ions, salinity, and trace metals. Whereas, E. coli is excessive in groundwater and surface water, and treatment is required before the water is used for drinking purpose. Groundwater and surface water are, however, suitable for agricultural purposes. The major ions are Ca2+, Mg2+, and HCO3−, and all water samples are predominantly of the HCO3–Ca·Mg type. Hierarchical cluster analysis (HCA) indicates that the water chemistry in the mining area is regulated by natural processes that are controlled by the different geological formations and different hydrogeological settings. Carbonate dissolution/precipitation is the key factor controlling the concentrations of Ca2+, Mg2+, and HCO3–. Pyrite oxidation is an important factor influencing the concentration of SO42–, whereas evaporation is a minor factor regulating the water chemistry in the mining area. The study results are beneficial for sustainable water quality management in the mining area, and they will also interest mine hydrogeologists and practitioners of the world as a reference for relevant studies in other regions.

Development of spatial similarity‐based modelling to improve integrated lake water quality management in Malaysia

AbstractThis study describes similarity‐based modelling techniques used to develop a spatially based water quality prediction model to facilitate sustainable lake water quality management. The lentic nature of lakes allows them to slowly absorb pollutants over a long period of time with readily noticeable signs, causing symptoms to appear only when the water quality has significantly degraded, meaning the risk of improper water quality management can be very high. Thus, failure to establish sustainable planning at the watershed scale was found to be a major threat of water quality degradation, from extemporary approaches often practised in lake management. Accordingly, the developed model is tailored for lakes facing moderate to serious water quality data limitation. The geodatabase integrates the identified driving factors of physical, social and water quality with significant influences on the status of lake water quality. A 1 km buffer radius with percentages of built‐up area, population, lake surface area and rainfall is measured. Calculation of a water quality index was then quantified on the basis of a similarity‐modelling technique. Lake Putrajaya was chosen as a control point for developing the indicator index. A total of 93 recreational lakes within Selangor and Kuala Lumpur were selected as modelling points. The results of this study indicated the similarity technique of spatial modelling is sufficiently reliable to be applied as an early assessment indicator. From the 93 lakes in this study, none feel in the category of either “bad” or “excellent,” with the majority being in class 3 (medium water quality status) and only four considered as having a good water quality condition. The balance of 35 lakes was considered to exhibit poor water quality. The model output is an indicator index, providing classification guidelines for the water quality status of the assessed lake as an early assessment tools.

Assessment and identification of nitrogen pollution sources in the Cheongmi River with intensive livestock farming areas, Korea.

This study aimed to develop methods for assessing and identifying nitrogen sources in the Cheongmi River, Korea, that has intensive livestock farming areas (ILFA) in its watershed. The assessment focused on the feasibility of the simultaneous use of stable isotopic compositions of ammonium (δ15NNH4) and nitrate (δ15NNO3) for identifying the main nitrogen pollution sources in the Cheongmi River watershed. Our results suggested that the organic nitrogen (Org-N) to total nitrogen (T-N) ratio could be used as an indicator for assessing the effect of livestock excreta on waterways in ILFA. We observed that the T-N concentration was much more strongly affected by livestock excreta than the T-P concentration in the mainstream of the Cheongmi River. The positive correlation was more significant between δ15NNH4 and NH4-N than that between δ15NNO3 and NO3-N for river water samples. Furthermore, the use of δ15NNH4 was more effective than that of δ15NNO3 in evaluating nitrogen variations between May and August in the Cheongmi River because the differences in δ15NNH4 between May and August were more remarkable compared to those in δ15NNO3. Finally, the simultaneous use of δ15NNH4 and δ15NNO3 showed that the dominant nitrogen source at sites M3, M4, M5, and M6, specifically in May, was livestock excreta in the Cheongmi River. The results of this study could be used for sustainable water quality management in the Cheongmi River watershed.

Spatiotemporal variations of hydrogeochemistry and its controlling factors in the Gandaki River Basin, Central Himalaya Nepal

The characterization and assessment of water quality in the head water region of Himalaya is necessary, given the immense importance of this region in sustaining livelihoods of people and maintaining ecological balance. A total of 165 water samples were collected from 55 sites during pre-monsoon, monsoon and post-monsoon seasons in 2016 from the Gandaki River Basin of the Central Himalaya, Nepal. The pH, EC values and TDS concentrations were measured in-situ and the concentrations of major ions (Ca2+, Mg2+, K+, Na+, Cl−, SO42−, NO3−) and Si were analyzed in laboratory. Correlation matrices, paired t-test, cluster analysis, principal component analysis (PCA), the Piper, Gibbs, and Mixing plots, and saturation index were applied to the measurements for evaluating spatiotemporal variation of the major ions. The results reveal mildly alkaline pH values and the following pattern of average ionic dominance: Ca2+>Mg2+>Na+>K+ for cations and HCO3−>SO42−>Cl−>NO3− for anions. The results of PCA, Gibbs plot and the ionic relationships displayed the predominance of geogenic weathering processes in areas with carbonate dominant lithology. This conclusion is supported by geochemically different water facies identified in the Piper plot as Ca-HCO3 (83.03%), mixed Ca-Mg-Cl (12.73.0%) and Ca-Cl (4.24%). Pronounced spatiotemporal heterogeneity demonstrates the influence of climatic, geogenic and anthropogenic conditions. For instance, the Ca2+-SO42−, Mg2+-SO42− and Na+-Cl− pairs exhibit strong positive correlation with each other in the upstream region, whereas relatively weak correlation in the downstream region, likely indicating the influence of evapo-crystallization processes in the upstream region. Analyses of the suitability of the water supply for drinking and irrigation reveal that the river has mostly retained its natural water quality but poses safety concern at a few locations. Knowledge obtained through this study can contribute to the sustainable management of water quality in the climatically and lithologically distinct segments of the Himalayan river basins.

Impact assessment of projected climate change on diffuse phosphorous loss in Xin'anjiang catchment, China.

Diffuse nutrient loss is a serious threat to water security and has severely deteriorated water quality throughout the world. Xin'anjiang catchment, as a main drinking water source for Hangzhou City, has been a national concern for water environment protection with payment for watershed services construction. Detection of diffuse phosphorous (DP) pollution dynamics under climate change is significant for sustainable water quality management. In this study, the impact of projected climate change on DP load was analyzed using SWAT to simulate the future changes of diffuse components (carriers: water discharge and sediment; nutrient: DP) at both station and sub-catchment scales under three climate change scenarios (RCP2.6, RCP4.5, and RCP8.5). Results showed that wetting and warming years were expected with increasing tendencies of both precipitation and temperature in the two future periods (2020s: 2021~2030, 2030s: 2031~2040) except in the 2020s in the RCP2.6 scenario, and the annual average increasing ratios of precipitation and temperature reached - 1.79~3.79% and 0.48~1.27°C, respectively, comparing with those in the baseline (2000s: 2001~2010). Climate change evidently altered annual and monthly average water discharge and sediment load, while it has a remarkable impact on the timing and monthly value of DP load at station scale. DP load tended to increase in the non-flood season at Yuliang due to strengthened nutrient flushing from rice land into rivers with increasing precipitation and enhanced phosphorous cycle in soil layers with increasing temperature, while it tended to decrease in the flood season at Yuliang and in most months at Tunxi due to restricted phosphorous reaction with reduced dissolved oxygen content and enhanced dilution effect. Spatial variability existed in the changes of sediment load and DP load at sub-catchment scale due to climate change. DP load tended to decrease in most sub-catchments and was the most remarkable in the RCP8.5 scenario (2020s, - 9.00~2.63%; 2030s, - 11.16~7.89%), followed by RCP2.6 (2020s, - 10.00~2.90%; 2030s, - 9.00~6.63%) and RCP4.5 (2020s, - 6.81~5.49%, 2030s, - 10.00~9.09%) scenarios. Decreasing of DP load mainly aggregated in the western and eastern mountainous regions, while it tended to increase in the northern and middle regions. This study was expected to provide insights into diffuse nutrient loss control and management in Xin'anjiang catchment, and scientific references for the implementation of water environmental protection in China.

Impacts of changes in groundwater recharge on the isotopic composition and geochemistry of seasonally ice-covered lakes: insights for sustainable management

Abstract. Lakes are under increasing pressure due to widespread anthropogenic impacts related to rapid development and population growth. Accordingly, many lakes are currently undergoing a systematic decline in water quality. Recent studies have highlighted that global warming and the subsequent changes in water use may further exacerbate eutrophication in lakes. Lake evolution depends strongly on hydrologic balance, and therefore on groundwater connectivity. Groundwater also influences the sensitivity of lacustrine ecosystems to climate and environmental changes, and governs their resilience. Improved characterization of groundwater exchange with lakes is needed today for lake preservation, lake restoration, and sustainable management of lake water quality into the future. In this context, the aim of the present paper is to determine if the future evolution of the climate, the population, and the recharge could modify the geochemistry of lakes (mainly isotopic signature and quality via phosphorous load) and if the isotopic monitoring of lakes could be an efficient tool to highlight the variability of the water budget and quality. Small groundwater-connected lakes were chosen to simulate changes in water balance and water quality expected under future climate change scenarios, namely representative concentration pathways (RCPs) 4.5 and 8.5. Contemporary baseline conditions, including isotope mass balance and geochemical characteristics, were determined through an intensive field-based research program prior to the simulations. Results highlight that future lake geochemistry and isotopic composition trends will depend on four main parameters: location (and therefore climate conditions), lake catchment size (which impacts the intensity of the flux change), lake volume (which impacts the range of variation), and lake G index (i.e., the percentage of groundwater that makes up total lake inflows), the latter being the dominant control on water balance conditions, as revealed by the sensitivity of lake isotopic composition. Based on these model simulations, stable isotopes appear to be especially useful for detecting changes in recharge to lakes with a G index of between 50 and 80 %, but response is non-linear. Simulated monthly trends reveal that evolution of annual lake isotopic composition can be dampened by opposing monthly recharge fluctuations. It is also shown that changes in water quality in groundwater-connected lakes depend significantly on lake location and on the intensity of recharge change.

Modeling of Water Resources Allocation and Water Quality Management for Supporting Regional Sustainability under Uncertainty in an Arid Region

In this study, a scenario-based interval-stochastic fraticle optimization with Laplace criterion (SISFL) method is developed for sustainable water resources allocation and water quality management (WAQM) under multiple uncertainties. SISFL can tackle uncertainties presented as interval parameters and probability distributions; meanwhile, it can also quantify artificial fuzziness such as risk-averse attitude in a decision-making issue. Besides, it can reflect random scenario occurrence under the supposition of no data available. The developed method is applied to a real case of water resources allocation and water quality management in the Kaidu-kongque River Basin, where encounter serve water deficit and water quality degradation simultaneously in Northwest China. Results of water allocation pattern, pollution mitigation scheme, and system benefit under various scenarios are analyzed. The tradeoff between economic activity and water-environment protection with interval necessity levels and Laplace criterions can support policymakers generating an effective and robust manner associated with risk control for WAQM under multiple uncertainties. These discoveries avail local policymakers gain insight into the capacity planning of water-environment to satisfy the basin’s integrity of socio-economic development and eco-environmental sustainability.

Numerical simulations of residence time and tracer travel time in Lake Poyang

在复杂湖泊水动力环境作用下，换水周期和传输时间变化直接影响着污染物的迁移和转化.本文运用数值模拟方法，定量研究了季节水情动态下鄱阳湖换水周期和示踪剂传输时间的空间分布.结果表明，不同季节下鄱阳湖换水周期均具有较高的空间异质性，贯穿整个湖区的主河道换水周期约<10 d，大多湖湾区的换水周期则长达300多天.尽管不同季节下换水周期空间分布格局几乎相似，但受鄱阳湖水动力场的季节变化影响，夏、秋季的换水周期要明显大于春、冬季.基于换水周期频率分布曲线的统计表明，80%的鄱阳湖区的换水周期约<30 d，其余湖区换水周期为几十天至几百天，表明鄱阳湖应该更加确切地描述为一个快速换水和慢速换水同时共存的湖泊系统.鄱阳湖示踪剂传输时间介于4~32 d，夏、秋季的传输时间（11~32 d）约为春、冬季（4~8 d）的4倍，主要与鄱阳湖季节性水情特征及示踪剂的迁移路径有关.本文所获取的换水周期和示踪剂传输时间的时空分布信息可为今后鄱阳湖水质、水环境和生态系统管理和维护等方面提供重要科学参考.;Many physical, chemical and biological processes that occur within particular environments, including the transport of pollutants, sediments and other materials, are influenced by lake hydrodynamics. The residence time and travel time of these materials are most commonly used to represent the time scale of the physical transport processes and to elucidate associated water quality problems in lakes. The main objective of this study was to investigate the residence time and tracer travel time in Lake Poyang. A 2D hydrodynamic model (MIKE 21) was combined with dye tracer simulations (advection-dispersion equation) to determine the residence and travel time of the lake for various seasons. The results indicate that Lake Poyang exhibits strong but spatially heterogeneous residence time that varies with the different seasons. Generally, the average residence time is shorter than 10 days along the lake's main flow channels due to the prevailing northward flow pattern. Whereas the local topographically controlled flow patterns substantially increase, the residence time in most bays is approximately longer than 300 days with high spatial values. Flushing homogeneity curves show that approximately 80% of the lake area has the residence time varied between a few days and approximately 1 month, and around 20% of the area has the values in the range from several months to several hundred days. The results demonstrate that Lake Poyang is a mixing water system, which can be divided into fast and slow flushing systems in different seasons. Model simulations also reveal that the tracer travel time of Lake Poyang is in the range of 4-32 days across the lake. Depending on the seasonal water level regimes and associated pollutant transport pathways, the travel time from the released sources to the lake outlet Hukou during the summer and autumn (varies between 11-32 days) is four times greater than that under the spring and winter (i.e., 4-8 days). The outcomes of this study provide important information regarding the sustainable management of water quality, water environment and ecosystem for Lake Poyang.

FINIFLUX: An implicit finite element model for quantification of groundwater fluxes and hyporheic exchange in streams and rivers using radon

AbstractA quantitative understanding of groundwater‐surface water interactions is vital for sustainable management of water quantity and quality. The noble gas radon‐222 (Rn) is becoming increasingly used as a sensitive tracer to quantify groundwater discharge to wetlands, lakes, and rivers: a development driven by technical and methodological advances in Rn measurement. However, quantitative interpretation of these data is not trivial, and the methods used to date are based on the simplest solutions to the mass balance equation (e.g., first‐order finite difference and inversion). Here we present a new implicit numerical model (FINIFLUX) based on finite elements for quantifying groundwater discharge to streams and rivers using Rn surveys at the reach scale (1–50 km). The model is coupled to a state‐of‐the‐art parameter optimization code Parallel‐PEST to iteratively solve the mass balance equation for groundwater discharge and hyporheic exchange. The major benefit of this model is that it is programed to be very simple to use, reduces nonuniqueness, and provides numerically stable estimates of groundwater fluxes and hyporheic residence times from field data. FINIFLUX was tested against an analytical solution and then implemented on two German rivers of differing magnitude, the Salzach (∼112 m3 s−1) and the Rote Main (∼4 m3 s−1). We show that using previous inversion techniques numerical instability can lead to physically impossible negative values, whereas the new model provides stable positive values for all scenarios. We hope that by making FINIFLUX freely available to the community that Rn might find wider application in quantifying groundwater discharge to streams and rivers and thus assist in a combined management of surface and groundwater systems.

Water quality variation in the highly disturbed Huai River Basin, China from 1994 to 2005 by multi-statistical analyses

Water quality deterioration is a prominent issue threatening water security throughout the world. Huai River Basin, as the sixth largest basin in China, is facing the most severe water pollution and high disturbance. Statistical detection of water quality trends and identification of human interferences are significant for sustainable water quality management. Three key water quality elements (ammonium nitrogen: NH3-N, permanganate index: CODMn and dissolved oxygen: DO) at 18 monitoring stations were selected to analyze their spatio-temporal variations in the highly disturbed Huai River Basin using seasonal Mann–Kendall test and Moran's I method. Relationship between surrounding water environment and anthropogenic activities (point source emission, land use) was investigated by regression analysis. The results indicated that water environment was significantly improved on the whole from 1994 to 2005. CODMn and NH3-N concentrations decreased at half of the stations, and DO concentration increased significantly at 39% (7/18) stations. The high pollution cluster centers for both NH3-N and CODMn were in the middle stream of Shaying River and Guo River in the 2000s. Water quality of Huai River Basin was mainly influenced by point source pollution emission, flows regulated by dams, water temperature and land use variations and so on. This study was expected to provide insights into water quality evolution and foundations for water quality management in Huai River Basin, and scientific references for the implementation of water pollution prevention in China.

Two-Stage Chance-Constrained Fractional Programming for Sustainable Water Quality Management under Uncertainty

AbstractIn this study, a two-stage chance-constrained fractional programming (TCFP) method is developed for dealing with water quality management problems associated with stochastic inputs. Two-stage chance-constrained fractional programming is a hybrid of stochastic linear fractional programming (SLFP) and two-stage stochastic programming (TSP) methods. It can not only balance objectives of two aspects through converting a bi-objective problem into a ratio one but can also analyze various policy scenarios when the promised production targets are violated. For demonstrating its advantages, the proposed TCFP method is applied to a case study of water quality management where managers have to consider conflicting objectives between economic development and environmental conservation, as well as stochastic features expressed as probability distributions. The obtained solutions under different significance levels can help managers to identify desired policies under various environmental, economic, and constra...

Defining limits to multiple and simultaneous anthropogenic stressors in a lake ecosystem – Lake Kinneret as a case study

In this study we expanded a recently developed approach for defining acceptable levels of management policy that will allow sustainable management of water quality in a lake ecosystem. A three dimensional solution space was created to define all acceptable scenarios of N loads, P loads and lake water level (WL) thus providing an integrated tool for defining the extent of measures that will allow lake ecosystem sustainability. The approach included use of a lake ecosystem model, a quantitative system of composite water quality indices (CWQIs) and defined sustainability criteria for the ecosystem. The approach was tested on the Lake Kinneret (Sea of Galilee) ecosystem and succeeded in defining the range of acceptable management policy through the use of long term simulations of different scenarios. Using the results of the scenarios, a number of polygons were created, defined as relative solution domain area (RSDA), which denote the permissible ranges of nutrient loads at different water levels. The polygon, and hence RSDA, boundaries represent critical values of nutrient loads allowing conservation of the lake water quality at each WL. By integrating all RSDA, a three dimensional solution space was created which defines all acceptable ranges of N loads, P loads and WL thus providing lake managers with an integrated tool for defining the extent of measures that will allow sustainability of the lake ecosystem. This novel approach is unique, and presents an example of implementation of a management tool that integrates an ecosystem model, multiple stressors and quantified water quality indices to determine limits of management actions. This approach may well be implemented to other lakes around the world suffering from water quality deterioration as a result of changes in water level and nutrients loads.

Catchments as reactors: a comprehensive approach for water fluxes and solute turnover

Sustainable water quality management requires a profound understanding of water fluxes (precipitation, run-off, recharge, etc.) and solute turnover such as retention, reaction, transformation, etc. at the catchment or landscape scale. The Water and Earth System Science competence cluster (WESS, http://www.wess.info/ ) aims at a holistic analysis of the water cycle coupled to reactive solute transport, including soil–plant–atmosphere and groundwater–surface water interactions. To facilitate exploring the impact of land-use and climate changes on water cycling and water quality, special emphasis is placed on feedbacks between the atmosphere, the land surface, and the subsurface. A major challenge lies in bridging the scales in monitoring and modeling of surface/subsurface versus atmospheric processes. The field work follows the approach of contrasting catchments, i.e. neighboring watersheds with different land use or similar watersheds with different climate. This paper introduces the featured catchments and explains methodologies of WESS by selected examples.

Towards a Consistent Approach for the Assessment and Redesign of Surface Water Quality Monitoring Networks

Water resources management in general, and water quality management in particular, requires both knowledge and a full understanding of the processes affecting water quantity and quality. A properly established water quality monitoring program is the only way in which one can understand various processes affecting water quality. It also provides managers and decision makers with the necessary information for effective and sustainable water quality management. Water quality monitoring programs consist of various activities, which include the designation of the monitoring objectives/purposes and the desired information, the design of the monitoring network and the sampling protocol, identification of the necessary laboratory analysis, a plan for data verification and storage, and the design of a data analysis protocol through which the desired information will be obtained. To ensure the utility of the generated data, the sampling processes, sample handling, and storage and laboratory analysis must be performed by professional staff. This is why the design of monitoring networks has generally been the activity that has received the most attention of researchers over the course of the last few decades [1-3]. However, as it stands now, there is no widely accepted established strategy or methodology for designing monitoring networks [2-3]. A logical and consistent design methodology that allows for more efficient and effective data collection and, consequently, more useful outputs, is critically needed. Such an approach would allow not only improved water pollution control recommendations and better allocation of financial resources, but also a better understanding of the ecosystem being monitored [3].