Quality assurance support tool for catchment-based modelling: a test on the HBV-NP model for eutrophication assessment

HarmoniQuA is an EU-project aiming at developing a methodological component of an infrastructure for modelling in water management according to the Water Framework Directive. The two major outputs are (1) a harmonised, generic methodology with guidelines for good modelling practice and (2) a web-based toolbox (MoST) for quality assurance support. To test the guidelines and the toolbox, they were applied during scenario analyses of nutrient transport in a pilot catchment in southern Sweden, using the recently developed HBV-NP model. HBV-NP is based on the hydrological HBV model, equipped with routines for N and P transport and transformation. Scenarios included business as usual, sector-specific measures and costeffective solutions. Results indicated that national goal of P reduction may be reached with widespread single measures, but N reduction requires combination of measures. Overall, the MoST tool performed well in providing guidance for the modelling and enabling detailed monitoring of the process. Some deficiencies were however identified which will be considered in the upgrade of MoST to its final version