Here nine keynote speakers were invited to talk about present use of models, current data collection for modelling besides from tangible examples on how modelling can support monitoring and vice versa. Most importantly there was room for discussion on the presented methods and for giving the implementers of the WFD the opportunity to put forward request to the modelling community.

State-of-the-art for modelling were discussed addressing topics like the current data collection for modelling and how this data collection fits into the ongoing process of the implementing the WFD etc. Besides, modellers were asked to estimate how much models would improve, if data collec­tion/monitoring could be designed to fit the individual model. Issues on optimal experimental design where models are used to increase the efficiency of monitoring were also addressed.

It was agreed that joint use of monitoring and modelling are very beneficial in terms of e.g. quality assurance of data, interpolation and extrapolation in time and space, in setting up a conceptual model, in estimating effects of anthropogenic activities as well as of environmental programmes of measures and finally in designing or optimising monitoring programmes. One of the conclusive remarks from the managers was that is was still unclear to many what is actually required to fulfil the WFD - it seems to be implemented in different ways in different countries. Besides lacking data is often a seriously limiting factor for modelling - data necessary for modelling should be available in publicly available databases on the internet. In this context the modelling side pointed out that it is essential to consider modelling objectives when estimating data demands for modelling, e.g. what the required level of confidence should be. The management side also found uncertainty issues important and saw models as needed to answer "what if" questions. Additionally, a guidance on a step by step application was suggested developed. Finally it was stated that good and tangible examples (pilots) on the usefulness of modelling in connection to monitoring are the way to the water managers or policy makers understanding and goodwill.

The workshop was held in Vilnius, Lithuania, in September 2005.