Background Despite significant investments made over the past decade in the treatment of wastewater from industries and households, challenges remain in achieving a good water quality across the whole of Europe. While the most discernible polluting sources are now being tackled, there is still a need for a more detailed analysis to determine remaining problems and to find out which measures can minimise the pollution load in rivers and significantly improve water quality and ecological status. Point and diffuse sources of pollution still need addressing. Good operational tools are needed for assessing these sources ahead of the devising of effective mitigation measures, especially for treating priority substances. To this end, European, national and regional policy-makers require powerful analytical instruments, such as Water Emissions Inventory Planning Support System (WEISS). Objectives The aim of the project, ‘WEISS - The Water Emissions Inventory, a planning Support System aimed at reducing the pollution of water bodies’, was to create an innovative Water Emissions Inventory Planning Support System (WEISS) to support competent authorities across Europe with the implementation of the Water Framework Directive (WFD). The tool would be used to: Determine significant emission sources and their contribution to the pollution of water bodies in order to formulate mitigation measures; and Control and monitor compliance with the objectives to prevent and decrease pollution. The WEISS tool would be a tool to generate a transparent inventory of all significant emissions, discharges and losses of water bodies caused by human activities. Results The main result of the project is the WEISS platform (http://weiss.vmm.be/geoloket/) for reporting emissions discharge and losses under Article 5 of the Environmental Quality Standards Directive. The WEISS model generates maps, calculates pathways and provides information on pollutant loads in kg per ha per day. It can also calculate emission trends based on water quality measurements. Furthermore, WEISS can be linked to water quality models though it is not itself such a model. It is, however, a model for distribution and transmission of pollutant emissions in surface watercourses, which allows users to calculate the effect of political decisions or economic developments on emissions into water. The Flemish Environmental Agency is now well equipped with a system to determine its significant emission sources and their contribution to the pollution of water bodies in line with the requirements of the Environmental Quality Standards EQS Directive. Indeed, the WEISS platform is a supporting tool for the formulation of mitigation measures and for controlling and monitoring in compliance with the WFD Directive. While the WEISS model is not innovative as such – emission models for water already exist – it does provide a high level of detail (resolution, point, diffuse and linear sources, pathways and number of pollutants) that feed into the model. The model performs better thanother water emission models currently used in Europe. Furthermore, it holds a high transferability potential as it is completely based on open source software. The socio-economic effects of this model, however, are not directly measurable. With a better knowledge of emissions, their pathways and final impact on water, it represents a new tool for decision making on infrastructure investments, protection status of specific areas, urban planning and permitting. It is expected that this will lead to more efficient planning, less environmental costs and potentially an improvement of life quality through better water quality. Finally, the project required an additional nine months to complete WEISS and to carry out dissemination activities in Belgium and further afield. To guarantee a continuation of the project results, the VITO-VMM partnership has been consolidated in the framework of the Flemish Government Reference tasks 2013-2018. Defined activities include the updating of the WEISS platform, adding functionalities depending on new needs, and improving the emission calculations. In the third newsletter of the partnership (24 November 201), it is reported that the WEISS model is now being used for the Brussels Capital Region and work on the model has also started in the Wallonia. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).