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Ecosystem service concepts can offer a valuable approach for linking human and nature, and arguments for the conservation and restoration of natural ecosystems. Despite an increasing interest in the topic, the application of these concepts for water resource management has been hampered by the lack of practical definitions and methodologies. In this study we review and analyse the current literature and propose an approach for assessing and valuing ecosystem services in the context of water management. In particular, to study the link between multiple pressures, ecological status and delivery of ecosystem services in aquatic ecosystems under different scenarios of measures or future changes. This is of interest for the development of River Basin Management Plans under the EU Water Framework Directive. We provide a list of proxies/indicators of natural capacity, actual flow and social benefit for the biophysical assessment of the ecosystem services. We advocate the use of indicators of sustainability, combining information on capacity and flow of services. We also suggest methods for economic valuation of aquatic ecosystem for each service and spatial scale of application. We argue that biophysical assessment and economic valuation should be conducted jointly to account for the different values of ecosystem services (ecologic, social and economic) and to strengthen the recognition of human dependency on nature. The proposed approach can be used for assessing the benefits of conservation and restoration of aquatic ecosystems in the implementation of the EU water policy. [ABSTRACT FROM AUTHOR]

The European environmental legislation on water, in particular the 2000 Water Framework Directive, requires the evaluation of nutrient pressures and the assessment of mitigation measures at the river basin scale. Models have been identified as tools that can contribute to fulfill these requirements. The objective of this research was the implementation of a modeling approach (Geospatial Regression Equation for European Nutrient losses (GREEN)) to assess the actual nitrogen pressures on surface water quality at medium and large basin scale (European scale) using readily available data. In particular the aim was to estimate diffuse nitrogen emissions into surface waters, contributions by different sources (point and diffuse) to the nitrate load in rivers, and nitrogen retention in river systems. A comprehensive database including nutrient sources and physical watershed characteristics was built at the European scale. The modeling partially or entirely covered some of the larger and more populated European river basins, including the Danube, Rhine, Elbe, Weser, and Ems in Germany, the Seine and Rhone in France, and the Meuse basin shared by France and Belgium. The model calibration was satisfactory for all basins. The source contribution to the in-stream nitrogen load, together with the diffuse nitrogen emissions and river nitrogen retention were estimated and were found to be in the range of values reported in the literature. Finally, the model results were extrapolated to estimate the diffuse nitrogen emission and source apportionment at the European scale. [ABSTRACT FROM AUTHOR]

Abstract: The characterisation of pollution sources impact on water quality and the implementation of river basin management plans require an analysis of the basin status including the dynamic of nutrient transfer and the relative significance of the different sources of pollution. Models can contribute in understanding the sources and the processes responsible for pollution, and identifying the areas of concern. A variety of methods have been used to model the nitrogen pressure in river basins. In this study we describe a comparison between two methodologies: a statistical model and the physically-based SWAT model. The two models were calibrated on the Wash catchment (UK), 8900km2. The nitrogen losses from land to surface waters and the source apportionment of riverine nitrogen load were estimated by the two approaches, and the results were compared. Moreover their potentiality for evaluating management strategies was analysed. [Copyright &y& Elsevier]

Abstract: This study describes a source apportionment methodology for riverine nitrogen transport. A statistical model was developed relating stream nitrogen load to spatially referenced nitrogen sources and basin characteristics. It is able to estimate the nitrogen load on the basis of only three parameters. It considers applied fertiliser, atmospheric deposition and point discharges as sources and rainfall, topography and water flow as basin characteristics. The model was calibrated on three European watersheds, the Wash (UK), the Zelivka (Czech Republic) and the Vilaine (France) river basins in order to represent a range of different climatic characteristics and nitrogen input pressures. Based on model predictions, the spatial and temporal variations of diffuse nitrogen emission were described, identifying critical areas more prone to nitrogen loss. The model makes it possible to estimate the contribution of each nitrogen sources (point and diffuse) to the total river load. Finally, scenarios of different nitrogen input pressure were analysed. The model was shown to be a suitable tool for understanding the fate of the actual nitrogen input pressure and evaluating the impact of alternative management strategies with a limited data requirement. [Copyright &y& Elsevier]

Good hygienic quality of surface waters is essential for drinking water production, irrigation of crops and recreation. Predictions of how and when microbes are transported by rivers are needed to protect downstream water users. In this study we tested the new process-based INCA-Pathogens model in the agricultural Loimijoki River basin (3138 km 2 ) in Finland, and we quantified ecosystem services of water purification and water provisioning for drinking and recreation purposes under different scenarios. INCA is a catchment scale process based model to calculate pollutant transfer from terrestrial environment and point sources to the catchment outlet. A clear gradient was observed in the numbers of faecal coliforms along the River Loimijoki. The highest bacterial counts were detected in the middle part of the main stream immediately after small industries and municipal sewage treatment plants. In terms of model performance, the INCA-Pathogen model was able to produce faecal coliform counts and seasonality both in the low pollution level sampling points and in the high pollution level sampling points. The model was sensitive to the parameters defining light decay in river water and in soil compartment, as well as to the amount of faecal coliforms in the manure spread on the fields. The modeling results showed that the number of faecal coliforms repeatedly exceeded 1000 bacteria 100 ml − 1 . Moreover, results lead to the following conclusions: 1) Climate change does not cause a major threat to hygienic water quality as higher precipitation increases runoff and causes diluting effect in the river, 2) Intensification of agriculture is not a threat as long as animal density remains relatively low and environmental legislation is followed, 3) More intensive agriculture without environmental legislation causes a threat especially in tributaries with high field percentage and animal density, and 4) Hygienic water quality in the River Loimijoki can best be improved by improving sewage treatment. We conclude that this catchment scale model is a useful tool for addressing catchment management and water treatment planning issues. [ABSTRACT FROM AUTHOR]