The use of catchment models in examining the relationships between management issues in catchments has improved in recent years with the development of new modelling tools, improvements in modelling science and greater understanding of the interrelationships in catchment management. The papers in this session should focus on how these new tools and/or science is improving the ability to model catchments in an integrated fashion and also outline how existing modelling tools may be enhanced through the adoption of revised methods. Further to the above, papers examining revised calibration and parameterisation methods in catchment modelling, in addition to resolving model uncertainties would be very welcome. The results of such modelling, where new techniques and/or tools have been applied are also encouraged.