Background Thirteen percent of Europe’s coastal bathing waters do not meet the standards set by 76/160/EEC Bathing Water Directive. In France, 20% of bathing waters are expected to be non-compliant unless action is taken. Pollution mostly comes from point sources and domestic wastewater. Tourism and demographic pressures in coastal areas are making it more difficult to reduce pollution, while at the same time increasing expectations of clean waters. Conventional solutions for the management of faecal pollution in domestic effluents work well in dry weather conditions, but fail to manage efficiently the flow rates generated by heavy rainfall. In rural areas, the size of sewage systems present additional difficulties. The project site includes 38 registered bathing locations and 15 production areas for mussels and oysters, including the largest site in France. On some days, more than 10 000 people harvest shellfish recreationally on the tideland. Objectives The MARECLEAN project covered the management and treatment of wastewater discharged to the sea and aims to prevent infectious diseases. The microbial seawater quality plays a key role in the sustainable development of costal areas. For the 40 km of coast covered, the project should immediately result in a 20% reduction of point source pollution rising to 70% with the application of a long-term management plan. Specific objectives included: Reducing the number of bathing sites rated “sufficient” according to the Bathing Water Directive from five to two and the number rated “insufficient” from three to none; Upgrading the rating of the most polluted mussels/oysters production area from “D” to “C”, and improving an area rated "B" to an "A" rating. At the end of the project there will be five zones rated “A”, six zones rated “B” and one rated “C”. The project aimed to further integrate pollution management into development plans. This would yield long-term economic benefits and avoid conflicts surrounding responsibility for pollution. At an EU level, the MARECLEAN method would be available for conducting risk assessments of faecal pollution in coastal areas (particularly those that border the Atlantic and North Sea), creating a local consensus on solutions and optimising environmental and economical benefits. The project would also add to knowledge of faecal pollution. Results The MARECLEAN project assessed the pollution load in rivers and the sea, taking more than 1 500 samples to measure continuous flow in nine rivers and sea water quality and velocity. From these measurements, the importance of short-term rainfall forecasts to pollution load became apparent. Point and diffuse sources of pollution were identified, with the most significant being identified as inland pasturing, followed by sewer overflow and salt marsh grazing. Data gathered were used to model pollution risks as a function of weather and sea conditions. The MARECLEAN team developed both a watershed load model (MAREFLUX) and a sea dispersion model (MARS). The project developed four transferrable decision-support tools: A tool for management of pumping stations overflow (this included a map of the potential impact of overflows at different pumping stations and the critical duration of overflows at different points, so that repairs can be prioritised). A tool for management of beach closures (the SAERS decision support system includes 32 scenarios for wet weather and 72 scenarios for infrastructure failures in dry weather). A tool for prioritising investment in pumping stations (based on technical status and critical overflow duration). A tool for prioritising the protection of river banks (based on the state of the riverbank and the critical load).In addition, MARECLEAN created a transferable pollution reduction tool for real-time sewer management to prevent beach pollution. The tool is based on the principles of making full use of storage capacities and engaging in preferential discharge to less sensitive areas. The method used to achieve this is to command pumping according to storage status and the immediate rainfall forecast. The project has also demonstrated to administrators the benefit of risk management for reducing water protection costs and has shown the importance of agricultural sources of pollution. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).