The social benefits of restoring water quality in the context of the Water Framework Directive: A comparison of willingness to pay and willingness to accept

The Water Framework Directive (WFD) is by far the most important piece of water legislation in Europe for the coming decades. Its main aim is to achieve “good ecological status” for all water resources by 2015. The economic valuation of the non-market benefits derived from improving water quality is an important input in assisting the design and implementation of efficient and effective water management policies. In this study, the contingent valuation method has been applied with a double purpose. On the one hand, we have estimated the value of a hypothetical improvement in water quality of a river asking individuals about their willingness to pay, and on the other hand, the issue of exemptions contemplated in the WFD has been addressed surveying people on their willingness to accept compensation if projected improvements were not carried out. Finally, a comparison of costs and benefits in a cost-benefit framework shows that the net present value of the water quality policy is positive both if we consider willingness to pay estimates as willingness to accept estimates, therefore this policy appears desirable from a social perspective.     

Establishing physico-chemical reference conditions in Mediterranean streams according to the European Water Framework Directive

Type-specific physico-chemical reference conditions are required for the assessment of ecological status in the Water Framework Directive context, similarly to the biological and hydro-morphological elements. This directive emphasises that natural variability of quality elements in high status (reference condition) needs to be quantified. Mediterranean streams often present a marked seasonal pattern in hydrological, biological and geochemical processes which could affect physico-chemical reference conditions. This study establishes general physico-chemical reference conditions (oxygenation, nutrient, salinity and acidification conditions) for different Mediterranean stream types. 116 potential reference sites located in 23 Mediterranean catchments in Spain were sampled in spring, summer and autumn in 2003. All sites were subjected to a screening method for the selection of reference sites in Mediterranean streams (Mediterranean Reference Criteria) and classified using a pre-established stream typology that establishes five different stream types (temporary streams, evaporite-calcareous at medium altitude, siliceous headwaters, calcareous headwaters and large watercourses). Reference conditions (reference value and reference threshold equivalents to high-good class boundary) were calculated using two different methods according to the availability of reference sites: the reference site 75th percentile approach of all reference sites and the 25th percentile of the population approach. The majority of the studied potential reference sites (76 out of 116) were selected as reference sites. Regarding type-specific reference conditions, only siliceous headwaters could be considered different from the rest of stream types because lower conductivity and pH. All reference stream types presented seasonal differences as regards some parameters, except for temporary streams due to the high natural variation of this stream type. For those parameters which presented seasonal differences in a specific stream type, the least restrictive values were proposed as reference conditions.     

Implementing the requirements of the Water Framework Directive for rural water supply schemes in Scotland

In a project pioneering the implementation of the European Union Water Framework Directive in Scotland, a programme of local stream flow gauging in Lochaber demonstrated that low flow yields in the sources were greater than predicted by standard methodologies for ungauged catchments in the UK. This meant that the abstraction required for the water treatment works represented an acceptable proportion of the yield, and complied with Scottish Environment Protection Agency guidance for maintaining good ecological status in the catchments. Development of new sources with dams, pumping stations and pipelines was avoided, thus reducing costs and environmental impacts. A programme of stakeholder consultations was carried out throughout the Water Order application process and agreement on proposed abstractions was reached with over 20 stakeholders.     

Challenges to the Implementation of the Water Framework Directive in Scotland: A Personal View

The Water Framework Directive was implemented in December 2000 and has to be transposed into Scottish legislation by 2003. The Directive provides a major opportunity to enhance the water environment of Scotland and to improve its management through the implementation of river-basin management planning with stakeholder and public engagement and the delivery of a programme of environmental-improvement measures to deliver good ecological status. Whilst the Directive provides unparalleled opportunities, there are significant challenges to its successful implementation in Scotland, where a step-change in managing the water environment will be required. This paper explores some of the challenges which include technical aspects, scale and timing issues, and capacity limitations.     

Maximum likelihood mixture estimation to determine metal background values in estuarine and coastal sediments within the European Water Framework Directive

Some of the recently derived European Directives, such as the Water Framework and Marine Strategy, have, as ultimate aims, to achieve concentrations of hazardous substances in the marine environment near background values. Hence, the determination of natural background levels, in marine sediments, is highly relevant. The present study proposes the use of the maximum likelihood mixture estimation (MLME) to determine regional background levels and upper threshold of metal concentration, with the Basque Country as a case study (with a data set of 575 samples, from estuarine and littoral areas, including both intertidal and subtidal sediments). The heuristic procedure is applied with unimodal data distributions (Cd, Cr, Fe and Ni) and the mixture density estimations, based upon maximum likelihood, are carried out with polypopulational data distributions (As, Cu, Mn, Hg, Pb and Zn). The upper limits of the distribution are proposed, as the limits between 'High Status' and 'Good Status' (according to the Water Framework Directive terminology). The regional upper limits were 0.45 microg g(-1) for Cd, 71 microg g(-1) for Cr, 53,542 microg g(-1) for Fe, 57 microg g(-1) for Ni, 24 microg g(-1) for As, 64 microg g(-1) for Cu, 447 microg g(-1) for Mn, 0.27 microg g(-1) for Hg, 66 microg g(-1) for Pb, and 248 microg g(-1) for Zn. The results from this study can assist further in the determination of sediment reference conditions, to assess chemical status, within the above-mentioned directives; likewise, it will be studied as a useful methodology in determining regional metal backgrounds in other European countries.     

Assessing remotely sensed chlorophyll-a for the implementation of the Water Framework Directive in European perialpine lakes

The lakes of the European perialpine region constitute a large water reservoir, which is threatened by the anthropogenic pressure altering water quality. The Water Framework Directive of the European Commission aims to protect water resources and monitoring is seen as an essential step for achieving this goal. Remote sensing can provide frequent data for large scale studies of water quality parameters such as chlorophyll-a (chl-a). In this work we use a dataset of maps of chl-a derived from over 200 MERIS (MEdium Resolution Imaging Spectrometer) satellite images for comparing water quality of 12 perialpine lakes in the period 2003-2009. Besides the different trophic levels of the lakes, results confirm that the seasonal variability of chl-a concentration is particularly pronounced during spring and autumn especially for the more eutrophic lakes. We show that relying on only one sample for the assessment of lake water quality during the season might lead to misleading results and erroneous assignments to quality classes. Time series MERIS data represents a suitable and cost-effective technology to fill this gap, depicting the dynamics of the surface waters of lakes in agreement with the evolution of natural phenomena.     

Water quality, nutrients and the European union's Water Framework Directive in a lowland agricultural region: Suffolk, south-east England

The water quality of 13 rivers in the lowland, agricultural county of Suffolk is investigated using routine monitoring data for the period 1981 to 2006 collected by the Environment Agency of England and Wales (EA), and its predecessors, with particular emphasis on phosphorus (as total reactive phosphorus, TRP) and total (dissolved and particulate) oxidised nitrogen (TOxN — predominantly nitrate NO₃). Major ion and flow data are used to outline fundamental hydrochemical characteristics related to the groundwater provenance of base-flow waters. Relative load contributions from point and diffuse sources are approximated using Load Apportionment Modelling for both TRP and TOxN where concurrent flow and concentration data are available. Analyses indicate a mixture of point and diffuse sources of TRP, with the former being dominant during low flow periods, while for TOxN diffuse sources dominate.Out of 59 sites considered, 53 (90%) were found to have annual average TRP concentrations greater than 0.05 mg P l^− 1, and 36 (61%) had average concentrations over 0.120 mg P l^− 1, the upper thresholds for ‘High’ and ‘Good’ ecological status, respectively. Correspondingly, for TOxN, most of the rivers are already within 70% of the 11.3 mg N l^− 1 threshold, with two rivers (Wang and Ore) being consistently greater than this.It is suggested that the major challenge is to characterise and control point-source TRP inputs which, being predominant during the late spring and summer low-flow period, coincide with the peak of primary biological production, thus presenting the major challenge to achieving ‘good’ ecological status under the Water Framework Directive. Results show that considerable effort is still required to ensure appropriate management and develop tools for decision-support.     

Stakeholder involvement and public participation: a critique of Water Framework Directive arrangements in the United Kingdom

Expert consensus regarding public consultation and participation on environmental matters favours a multilevel approach: the process is much more likely to succeed when those consulted can relate to the boundaries, scale and the local nature of the issues. The Water Framework Directive requires those with the responsibility for river basin management planning to engage with stakeholders and the general public when such plans are being developed. Examination of the arrangements for public participation in the regions of the United Kingdom shows a marked variation in the interpretation of the Directive that may leave the general public residing in England and Wales at a significant disadvantage. In both Scotland and Northern Ireland involvement by the general public is planned at a much more local level through groups established specifically for that purpose. Arrangements at local level in England and Wales are focused on narrower existing liaison arrangements in place before the implementation of the Directive.     

Dissolved metal background levels in marine waters, for the assessment of the physico-chemical status, within the European Water Framework Directive

The European Water Framework Directive (WFD) has, as its ultimate aim, a reduction in the concentrations of hazardous substances in the marine environment, i.e. 'background' values. Hence, the determination of natural background levels of heavy metals, to distinguish between natural element concentrations and anthropogenically-influenced concentrations, is highly relevant. Some studies have shown the convenience in the derivation of local background levels, especially if they are necessary for environmental assessment. Nevertheless, although such studies exist for sediments, there are only a few previous investigations on metal background values in sea water. Likewise, there is not any standard procedure to determine such levels in waters, nor general agreement on the statistical methodologies to be applied. In this contribution, background levels of heavy metals (As, Cu, Mn, Ni, Pb and Zn), in estuarine and coastal waters within the Basque Country (northern Spain), according to ranges in salinity, are estimated using statistical tools. Ni and Pb have been considered elsewhere (2455/2001/EC) as priority substances under the WFD. Hence, this approach can assist further in the determination of water reference conditions, to assess chemical and physico-chemical status in other European countries; this, affects, ultimately, the ecological status, as defined within the WFD.     

A review of catchment management in the new context of drinking water safety plans

By managing a catchment effectively, the range and amount of contaminants entering waters used for public water supply can be reduced, with resultant benefits for both water companies and consumers. Consequently, catchment management is increasingly being recognised as being at the heart of the water environment. An overview of current and previous catchment management initiatives is given, along with the European Landscape Convention, which could be used as a vehicle for the implementation of a national catchment management strategy. The adoption of the drinking water safety plan approach is strongly advocated by the World Health Organisation, and effective catchment management underpins this approach. Effective management of our catchments will also make a significant contribution to meeting our obligations under the Water Framework Directive, by helping to address the serious issue of diffuse pollution from agriculture.     

Using multivariate factor analysis to assess surface/logged water quality and source of contamination at a large irrigation project at Al-Fadhli,Eastern Province,Saudi Arabia

A multivariate statistical technique, factor analysis, has been used to assess the impact of irrigation on near-surface water at a farm at Fadhli, Eastern Province, Saudi Arabia. A total of 34 surface water samples were analyzed for 23 different water quality parameters including pH, TDS, conductivity and alkalinity, sulphate, chloride, bicarbonate, nitrate, phosphate, bromide, fluoride, calcium, magnesium, sodium, potassium, arsenic, boron, copper, cobalt, iron, lithium, manganese, molybdenum, nickel, selenium, mercury, and zinc. The water quality data were subjected to both Q-mode and R-mode factor analysis. R-mode analysis resulted in three major factors for both summer and winter sampling events. Factor 1 (representing 48.91% of the summer and 53.66% of the winter variance) comprised elements likely to be due to the application of fertilizers and the dissolution of soil material. Factor 2 (14.04% of the summer and 11.94% of the winter variance) included elements common in irrigation water (related to the dissolution of aquifer materials). Factor 3 (7.36% of the summer and 10.18% of the winter variance) included molybdenum, manganese and nickel, which are common in micro-nutrients. Q-mode analysis showed that the most affected areas are located at the northwest corner of the farm.      

Assessment of the surface water quality in Northern Greece

The application of different multivariate statistical approaches for the interpretation of a large and complex data matrix obtained during a monitoring program of surface waters in Northern Greece is presented in this study. The dataset consists of analytical results from a 3-yr survey conducted in the major river systems (Aliakmon, Axios, Gallikos, Loudias and Strymon) as well as streams, tributaries and ditches. Twenty-seven parameters have been monitored on 25 key sampling sites on monthly basis (total of 22,350 observations). The dataset was treated using cluster analysis (CA), principal component analysis and multiple regression analysis on principal components. CA showed four different groups of similarity between the sampling sites reflecting the different physicochemical characteristics and pollution levels of the studied water systems. Six latent factors were identified as responsible for the data structure explaining 90% of the total variance of the dataset and are conditionally named organic, nutrient, physicochemical, weathering, soil-leaching and toxic-anthropogenic factors. A multivariate receptor model was also applied for source apportionment estimating the contribution of identified sources to the concentration of the physicochemical parameters. This study presents the necessity and usefulness of multivariate statistical assessment of large and complex databases in order to get better information about the quality of surface water, the design of sampling and analytical protocols and the effective pollution control/management of the surface waters.     

Spatial analysis of water quality trends in the Han River basin, South Korea

Spatial patterns of water quality trends for 118 sites in the Han River basin of South Korea were examined for eight parameters-temperature, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended sediment (SS), total phosphorus (TP), and total nitrogen (TN). A non-parametric seasonal Mann-Kendall's test determined the significance of trends for each parameter for each site between 1993 and 2002. There are no significant trends in temperature, but TN concentrations increased for the majority of the monitoring stations. DO, BOD, COD, pH, SS, and TP show increasing or decreasing trends with approximately half of the stations exhibiting no trends. Urban land cover is positively associated with increases in water pollution and included as an important explanatory variable for the variations in all water quality parameters except pH. Topography and soil factors further explain the spatial variations in pH, COD, BOD, and SS. BOD, COD, SS, and TP variations are consistently better explained by 100m buffer scale analysis, but DO are better explained by the whole basin scale analysis. Local water quality management or geology could further explain some variations of water quality. Non-point-source pollution exhibits strong positive spatial autocorrelation as measured by Moran's I, indicating that the incorporation of spatial dimensions into water quality assessment enhances our understanding of spatial patterns of water quality. The spatial regression models, compared to ordinary least square (OLS) models, always better explain the variations in water quality. This study suggests that spatial analysis of watershed data at different scales should be a vital part of identifying the fundamental spatio-temporal distribution of water quality.     

Long-term water quality monitoring of the Sejnane reservoir in northeast Tunisia

The Sejnane reservoir in northeast Tunisia provides drinking and irrigation water. Long-term water quality monitoring data including precipitation, evaporation, temperature, pH, conductivity, dissolved oxygen, turbidity, total suspended solids, major anions and cations, fluoride, BOD₅, NO₃ ⁻, NO₂ ⁻, NH₄ ⁺, P _tot, fecal coliform bacteria, boron and heavy metals (Fe, Zn, Cu, Ni, Pb, Cr and Cd) are reported. The appropriateness for irrigation was estimated by the SAR and Na percentage and the water quality assessed using the Canadian Water Quality Index as good to excellent, which confirmed its suitability for drinking, aquatic life and irrigation purposes.      

Adaptation and evaluation of the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) for use as an effective tool to characterize drinking source water quality

Protecting drinking source water quality is a critical step in ensuring a safe supply of drinking water. Increasingly, drinking source water protection programs rely on the active participation of various stakeholders with differing degrees of water science knowledge. A drinking source water quality index presents a potential communication and analysis tool to facilitate cooperation between diverse interest groups as well as represent composite water quality. We tested the effectiveness of the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) in capturing expert assessments of drinking water quality. In cooperation with a panel of drinking water quality experts we identified a core set of parameters to reflect common source water concerns. Drinking source water target values were drafted for use in the index corresponding to two basic treatment levels. Index scores calculated using the core parameter set and associated source water target values were strongly correlated with expert assessments of water quality. We recommend a modified index calculation procedure to accommodate parameters measured at different frequencies within any particular study period. The resulting drinking source water CCME WQI provides a valuable means of monitoring, communicating, and understanding surface source water quality.     

River water quality of the River Cherwell: an agricultural clay-dominated catchment in the upper Thames Basin, southeastern England

The water quality of the River Cherwell and a tributary of it, the Ray, are described in terms of point and diffuse sources of pollution, for this rural area of the upper Thames Basin. Point sources of pollution dominate at the critical ecological low flow periods of high biological activity. Although the surface geology is predominantly clay, base flow is partly supplied from springs in underlying carbonate-bearing strata, which influences the water quality particularly with regards to calcium and alkalinity. The hydrogeochemistry of the river is outlined and the overall importance of urban point sources even in what would normally be considered to be rural catchments is stressed in relation to the European Unions Water Framework Directive. Issues of phosphorus stripping at sewage treatment works are also considered: such stripping on the Cherwell has reduced phosphorus concentrations by about a factor of two, but this is insufficient for the needs of the Water Framework Directive.     

Applying global sensitivity analysis to the modelling of flow and water quality in sewers

While several approaches for global sensitivity analysis (GSA) have been proposed in literature, only few applications exist in urban drainage modelling. This contribution discusses two GSA methods applied to a sewer flow and sewer water quality model: Standardised Regression Coefficients (SRCs) using Monte-Carlo simulation as well as the Morris Screening method. For selected model variables we evaluate how the sensitivities are influenced by the choice of the rainfall event. The aims are to i) compare both methods concerning the similarity of results and their applicability, ii) discuss the implications for factor fixing (identifying non-influential parameters) and factor prioritisation (identifying important parameters) and iii) rank the important parameters for the investigated model. It was shown that both methods lead to similar results for the hydraulic model. Parameter interactions and non-linearity were identified for the water quality model and the parameter ranking differs between the methods. For the investigated model the results allow a sound choice of output variables and rainfall events in view of detailed uncertainty analysis or model calibration. We advocate the simultaneous use of both methods for a first model assessment as they allow answering both factor fixing and factor prioritisation at low computational cost.     

Optimal selection of location for Taiwanese hospitals to ensure a competitive advantage by using the analytic hierarchy process and sensitivity analysis

Implementation of the National Health Insurance scheme in Taiwan since 1995 has intensified competition in the local medical sector. Given elevated living standards island wide, Taiwanese residents have become more health conscious and attach increasing importance to quality healthcare, explaining the heightened consumer demand in the quality and scope of medical services. Additionally, the medical service sector has improved its organizational structure and encouraged hospitals to establish management practices that would increase their competitiveness. In such an intensely competitive environment, selecting the optimal location of hospitals to be established is of priority concern. Therefore, this work presents an analytic hierarchy process (AHP)-based evaluation model. Sensitivity analysis is performed in detail by varying the objective factor decision weight, the priority weight of subjective factors and the gain factors. Adopted herein is the renowned diamond model introduced in Porter's The Competitive Advantage of Nations (1990) that influences how competitive advantages, especially with respect to developing and evaluating the objectives of optimal location selection, are related in order to devise a standardized operational procedure. Besides a literature review and interviews with experts, this study also adopts the modified Delphi method, the AHP and the sensitivity analysis to develop an evaluation method for selecting the optimal location of a regional hospital in Taiwan to determine its effectiveness. The proposed evaluation criterion provides a valuable reference for hospital administrators and academics in establishing a standardized means of selecting the optimal location for new medical care facilities.     

Assessing the improvement of the Bilbao estuary water quality in response to pollution abatement measures

To evaluate the success of almost 20 years of pollution abatement in the Bilbao estuary watershed in northern Spain, we analyzed temporal trends in pollution discharges and water quality from 1993 to 2003. Over that period a great portion of the raw wastewater discharge was intercepted and treated, leading to a significant reduction in the pollution load to the estuary (51.8% in biochemical oxygen demand, 70.9% in ammonia nitrogen and 81.9% in faecal coliforms). Temporal trends of mean annual levels of water quality variables showed statistically significant increases in dissolved oxygen saturation (between 2.04 and 4.11%/year) and decreases in ammonia nitrogen (between -4.15 and -175.75 microM NH3/year) and faecal coliforms concentrations (from 2.55 x 10(5) to 2.13 x 10(4) CFU/100ml). The improvement of the Bilbao estuary water quality reported in this paper is primarily attributed to the pollution abatement measures accomplished by the local water authority. Finally, as a result of these pollution control efforts, European bathing water quality standards were met at local beaches.     

Multivariate statistical techniques for the evaluation of spatial and temporal variations in water quality of Gomti River (India)--a case study

This case study reports different multivariate statistical techniques applied for evaluation of temporal/spatial variations and interpretation of a large complex water-quality data set obtained during monitoring of Gomti River in Northern part of India. Water quality of the Gomti River, a major tributary of the Ganga River was monitored at eight different sites selected in relatively low, moderate and high pollution regions, regularly over a period of 5 years (1994-1998) for 24 parameters. The complex data matrix (17,790 observations) was treated with different multivariate techniques such as cluster analysis, factor analysis/principal component analysis (FA/PCA) and discriminant analysis (DA). Cluster analysis (CA) showed good results rendering three different groups of similarity between the sampling sites reflecting the different water-quality parameters of the river system. FA/PCA identified six factors, which are responsible for the data structure explaining 71% of the total variance of the data set and allowed to group the selected parameters according to common features as well as to evaluate the incidence of each group on the overall variation in water quality. However, significant data reduction was not achieved, as it needed 14 parameters to explain 71% of both the temporal and spatial changes in water quality. Discriminant analysis showed the best results for data reduction and pattern recognition during both temporal and spatial analysis. Discriminant analysis showed five parameters (pH, temperature, conductivity, total alkalinity and magnesium) affording more than 88% right assignations in temporal analysis, while nine parameters (pH, temperature, alkalinity, Ca-hardness, DO, BOD, chloride, sulfate and TKN) to afford 91% right assignations in spatial analysis of three different regions in the basin. Thus, DA allowed reduction in dimensionality of the large data set, delineating a few indicator parameters responsible for large variations in water quality. This study presents necessity and usefulness of multivariate statistical techniques for evaluation and interpretation of large complex data sets with a view to get better information about the water quality and design of monitoring network for effective management of water resources.