Sediments and sediment management play a fundamental role in the management of rivers and their quality. The Upper (Austria) and Middle Danube (Hungary) are facing sediment related problems (e.g. river bed erosion) impacting the ecological condition, flood risk management, navigation and hydropower. Since water and sediments don’t regard borders, a cross border cooperation is needed in the area of field monitoring, numerical and physical modelling and practical river engineering measures. SEDDON II continues the basic achievements reached in SEDDON and focuses on the implementation of the suggested improvements. SEDDON II aims to improve knowledge and knowledge transfer from science to river management. Studies based on longer-term programs will lead to targeted and efficient measures in order to improve the ecological status and flood risk management. The key outputs of the project are i) a modern hydraulic engineering laboratory (HEL), being a unique research infrastructure with a discharge of up to 10 m³/s, allowing the study of basic processes and interrelations with river engineering measures; ii) a joint monitoring and modelling system, including the set up of new sediment monitoring stations and an expeditionary river survey system (ERiSS) in the HU section of the Danube, similarly to the station already existing in AT, and a comprehensive modelling throughout the project implementation, covering low, mean and high flow situations; iii) a guideline for joint river engineering measures based on the combination of large scale physical modelling with new numerical modelling using data from field monitoring. By using the new HEL an innovative infrastructure is available for exchanging knowledge between AT and HU, including experts, students and the public (also in the framework of the EUSDR flagship project DREAM). From the outcomes of SEDDON II the entire population along the Danube River will benefit.