Background Eutrophication tends to occur in ponds and reservoirs with excessive nutrient content. This can lead to the formation of blue-green algae blooms that can generate bio-toxins, which are a danger to the environment and wildlife and also to human health via bathing and drinking water. Blue-green algae blooms can develop in short timescales (days) and at different localities in the reservoir, which entails difficulties for monitoring. A means of providing efficient and effective management of surface water eutrophication is therefore of great urgency. According to the ‘WISE’ database of the European Environmental Agency, approximately half of all Spanish reservoirs are at risk of eutrophication. One Spanish reservoir defined as eutrophic is Cuerda del Pozo in Soria (Castilla y Leon, Spain). This represents an excellent case study because it has many uses, including as a water supply to the city of Soria (100 000 inhabitants), for recreation, and as a water supply for cattle. Objectives The main objective of the ROEM-plus project was to demonstrate the efficiency and viability of an innovative approach for the integrated management of hydrographic basins to prevent eutrophication and algal blooms. The project aimed to deploy remote sensor networks (e.g. meteorological, phytoplankton) within the whole geographic area connected to the Cuerda del Pozo reservoir, to quantify and localise the origin of pollutant and nutrient discharges, and assess the impact of territory use, forest, agricultural and livestock management. The remote, continuous and autonomous monitoring data system was designed to feed into an integrated decision-supporting ‘e-platform’ tool, to generate dynamic and spatially-distributed simulation models based on in-depth analysis of all key processes and elements. Results ROEM-plus delivered an integrated and cost-effective technological solution for the environmental monitoring of water systems in rural areas with high replicability potential all over the EU. The project pioneered the development of a real-time monitoring system for the comprehensive management of river basin pressures. In particular, the project developed an information and management ‘e-platform’, based on cutting-edge remote sensor networks (high time and spatial resolution) connected to predictive simulation systems. This innovative tool enables priorities for action to be assigned in relation to area and water use, so these can realistically absorb and buffer impacts and pressures. This approach makes it possible to avoid past management errors caused by excessive uncertainty, such as inappropriate investments in sewage treatment plants. Monitoring the effects of different natural processes and pressures throughout the Duero River Basin and waterways has enabled the project to achieve a set of specific results, including alarm systems for algae blooms, an (almost) real-time environmental information system, and a model (case study) that can be exported to other river basins. As an immediate consequence of the project, an optimised management of eutrophication and pollution stressors was obtained for the project area, due to the forecasting of the performance of the different combinations of corrective actions (e.g. in controlled wetland, agroforestry and livestock management) and the minimisation of uncertainties and costs. Indeed, the project’s outcomes have enabled a highly improved management of fish stock populations in the reservoir, provided an information platform usable by other environmental actors and territory managers, and facilitated local benefits through new potential economic activities in rural areas. The ROEM-plus monitoring system has detected cyanobacteria blooms near the demonstration reservoir dam since 2010 that would probably not otherwise have been detected. The project has gone beyond the strict enforcement of the Water Framework Directive, by not only analysing the physical conditions of the water masses (according to the criteria established in the Annex V of the Directive) but also modelling the relevant processes. This provided a greater understanding of the quantitative and qualitative situation of the status of the water masses in the project area, which resulted in a proposed plan of corrective actions to achieve “good ecological status” in the target reservoir. The assessment of the different pressures includes the analysis of the anthropogenic influences that have led to the current conditions of the Cuerda del Pozo dam. The project also helps implement other European directives concerning water quality (e.g. 2008/105/EC; 2006/44/EC; 2006/7/EC), wastewater treatment (91/271/EEC) and nitrate pollution (91/676/EEC). The project brings environmental and socioeconomic benefits, especially through reduced risk of toxicity from proliferating cyanobacteria. Benefits also include reduced fish death by suffocation or poisoning, less ecological damage due to invasive species and downstream algae growth, reduced clogging and pollution loads, and avoidance of imbalances in gases (e.g. hypoxia, anoxia and oxygen saturation), water chemistry or pH. The implementation of corrective measures (e.g. wetland management) could also create jobs and benefit local communities via improved nature recreation and fishing opportunities. Public managing bodies of various river basins in Spain have showed interest in the implementation of the system validated by the project, but the current budgetary limitations of the public entities in Spain are a barrier. In this regard, the beneficiaries see more possibilities for the replication of the project in reservoirs/dams managed by private entities (mainly dams for hydropower generation). Other entities are already assessing the implementation of actions inspired by the ROEM-plus project, in particular: In the dam of Cogotas (Ávila), which has serious problems of euthophication, the Confederación Hidrográfica del Duero is fostering the implementation of a similar system; The Spanish Ministry of Environment and the Regional Government of Castilla-León are weighing up the implementation of a strategy inspired by the project in Sanabria Lake Natural Park (the largest glacial lake in Spain); The Provincial Council of Pontevedra is drafting an Action Plan for the Umia river basin; and EMALCASA (municipal water company of the city of A Coruña), a company that manages some of the reservoirs for the water supply of A Coruña, is planning to incorporate the technology for water monitoring.Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).