Use of models to support the monitoring requirements in the water framework directive

Implementation of the EU Water Framework Directive (WFD) poses many new challenges to European water managers. Monitoring programmes play a key role to assess the status and identify possible trends in the environmental conditions of river basins; to gain new knowledge on water processes and to assess to which extent implemented measures actually have the expected effects in terms of improving the environmental status. Despite a general acknowledgement in the scientific community on the benefits of using monitoring and modelling jointly, it has not been the common practise in the European monitoring programmes so far. Several obstacles may be identified which limits the joint use of monitoring and modelling, such as lack of the required skill, lack of time, lack of confidence in models but also a lack of awareness on how models can be used in practise. In this paper we provide examples on how modelling can support the monitoring programmes to meet the objectives of the monitoring programmes in the WFD more efficiently. The extent to which the monitoring requirements in the WFD can be expected to supply sufficient data for modelling purposes is further addressed. This question is, however, not well posed, as the data requirement for modelling is highly dependent on the required accuracy of the model results.