Monitoring is an important part of large regulations and guide lines, like the European Water Framework Directive, the Nitrates Directive, the Marine Strategy Framework Directive and the Groundwater Directive. Nevertheless, these directives are not very explicit how efficient and effective monitoring programs should be designed and how trends should be deduced from the monitoring programs. In addition, in the past years observation devices and sensor technology has developed rapidly. Amongst others, interesting developments are
- The increased use of high frequent, semi-continuous observation methods, using water pressure sensors, ion selective sensors, field auto-analyzers and lab-on-a-chip approaches,
- New opportunities which arise from the use of passive samplers, which results in time-averaged data where high frequencies are filtered out,
- New opportunities for combining spatial average sampling by remote sensing and ground truth from regular observation networks.
These new data acquisition approaches ask for new strategies for monitoring, both in the design, data analysis and optimization phases of both scientific experiments and long term monitoring set-ups. In the 2012 session it appeared to be useful to discuss issues from the monitoring perspective, rather than from hydrological compartments. In the 2013 session the issues that will be addressed are:
- efficient monitoring strategies for detecting permanent changes of a system in time (trends)
- efficient monitoring strategies for assessing the chemical or biological status of a system at a specific moment in time (status)
- Statistical methods for trend analysis
- possibilities of new measurement equipment for efficient monitoring,
- effective use of high frequent measurement equipment for nutrients and isotopes (222Rn, 18O, 2H)
- effective use of time averaged sampling methods, both chemical and biological
- simultaneous monitoring of different parameters and different hydrological compartments,
- use of models in the design of monitoring strategies
Contributions are encouraged from a wide range of disciplines, including water quality, water quantity and ecological aspects of marine waters, surface water and groundwater. The aim of the session is to bring together scientists from multiple disciples, in order to interchange experiences in monitoring design, data-analysis and optimization methods.

Invited: Andrew Wade et al. New insights into hydrochemical processes in lowland river systems gained from in situ, high-resolution monitoring