During the last five years Harmoni-CA has been working among other things to promote the use of modelling tools in Integrated River Basin Management, especially in the implementation process of the Water Framework Directive. Within Harmoni-CA WP4 has worked to promote the interaction of monitoring and modelling activities. This has been done through 4 workshops where water managers, consultants, policy makers etc. have been brought together with researchers to elaborate state of the art on monitoring programmes; on present practice in use of models and to be presented for the possibilities, potentials and benefits of joining modelling and monitoring. Constraints and bottlenecks have been discussed and input and output from the workshops has been used to produce a guideline in best practice in joint use of monitoring and modelling as well as a synthesis report on data availability and accessibility. At this last workshops the guideline and the synthesis report will be tested and evaluated by inviting practitioners etc. to let these elaborate real life case studies by using the recommendations, ideas and principles sketched in the documents. By the term "practitioners" we aim at persons working with implementation of the water framework directive in terms of water management issues as well as consultants and researchers/advisors from other institutes as universities etc. As the previous workshops this also aims at promoting the communication and exchange of ideas and experiences between participants.