Background The sustainable management of Europe’s water resources are a real challenge for water system managers in the context of climate change and demographic developments. The European Environment Agency 'State of Water' report highlights worrying trends, showing an increase in, and wider prevalence of, water scarcity and stress. By 2030, this is expected to affect about half of EU river basins. To respond to this, in addition to improving water allocation based on ecological flow, water efficiency measures should be taken to save water and, in many cases, to save energy too. These issues are addressed by the EU Water Framework Directive (WFD), which establishes a legal framework to protect and restore clean water in Europe, and to ensure its long-term, sustainable use. The directive's approach to water management is based on river basins, which are the natural geographical and hydrological units. The WFD sets deadlines for Member States to protect aquatic ecosystems, and covers inland surface waters, transitional waters, coastal waters and groundwater. However, measuring the ecological status of temporary rivers and how this affects their management remains an open question to be dealt with under the WFD, for the following reasons: 1. The WFD requires rivers to be classified on the basis of well defined typologies in order to apply appropriate river basin management plans. However, the typologies considered so far at European level do not explicitly refer to temporary streams. Spanish and Italian transpositions of the WFD recognised the need for defining diverse types of temporary streams, but did not develop guidelines for status assessments or temporary-river management; 2. In most cases, because of the lack of regulations and procedures, managers are forced to apply perennial river management principles when making decisions about the ecological status of temporary rivers, and when undertaking measures such as water allocation, river engineering, effluent discharge and restoration; and 3. The distinct hydrological variability of temporary streams clearly affects their pollution dynamics. Practical measures related to: (i) inputs from nutrients and organic matter from sewage effluent; (ii) erosion; (iii) remediation of stream sediments containing hazardous substances; and (iv) integrated flood management, should be included in management plans for temporary rivers. Objectives The project will contribute to solving the problems related to the assessment of the ecological status of temporary streams through the development of software (TRESH) which, using hydrological and climatic data, can evaluate the river typology and the hydrological situation of the water body concerned. Using two new concepts, Aquatic States and Hydrological Status, the TRESH software will provide managers with relevant data on the hydrological conditions in the river, and a calendar for taking samples at the right times to be comparable to those from permanent streams. The project's outcomes will serve as a basis for the sound implementation of WFD river basin management plans and the evaluation of the effectiveness of mitigation measures in much of Spain and, hopefully, the whole of Europe (with a particular focus on the rivers of southern Europe). Expected results: 1. An operational software tool designed for water managers for the sound diagnosis of the ecological status of temporary rivers; 2. Collection of data (hydrological, physiochemical and biological) to assess variability at natural and impacted sites in 25 test water bodies; 3. A database with about 500 records for each basin; 4. Characterisation of more than 100 temporary streams based on their lifecycle and the implications for aquatic life; 5. Evaluation of the relationships between the variability of hydrological and physiochemical conditions and their effect on aquatic life in 25 pilot basins; 6. State of the art guidelines and field protocols for the WFD implementation, including the measurement of ecological status and the definition of, and methods for, measuring hydrological status; 7. A review of approaches and methods in Spain for the preparation of river basin management plans, with a particular focus on temporary streams; and 8. An application designed for tablets and smartphones to be used by managers to detect and report on pressures and impacts in temporary rivers. This application will also serve as a method to establish their ecological status in a simplified manner.