Hydrodynamic and water quality modelling: case studies

Three case studies of water quality modelling are presented: (1) 3D modelling of circulation and of nutrient transport and dispersion in an alpine lake; (2) 2D modelling of mercury cycling in the Trieste Bay (Northern Adriatic); here some of the main bio-chemical processes such as sedimentation, methylation, and demethylation are simulated; (3) a 3D, long term simulation of dispersion of radioactive pollutants in the Japan sea, where thermohaline forcing is the main forcing factor. In these simulations the hydrodynamic and mass-transport models LMT2D and LMT3D, described in a companion paper (Rajar, R. and Cetina M., 1997), are used. Different methodologies for coupling hydrodynamic sub-models with mass transport sub-models into integrated water quality models are described. The choice of the methodology depends on the space and time scales, on the prevalent forcing factors and on the nature of the contaminant.