Environmental management and numerical models: examples from long-term ecological research on a real case study

Numerical models provide a framework for the integration and synthesis of existing knowledge about an ecosystem, and might offer important contributions for understanding the scale of human disturbance and the potential effectiveness of restoration action. In addition they provide the quantitative knowledge which is required for evaluation, at ecological and economic levels, of consequences of the implementation of possible alternative scenarios of policy options. Coastal areas and estuaries are particularly important sites, since they are very sensitive to anthropogenic impact and are very valuable.. We present applications of a long-term modeling study on the Lagoon of Venice, which is the largest Italian lagoon. A suite of models, including a 3D fully coupled transport-water quality model, has been developed, validated against a substantial amount of real world data, and used to investigate nutrient cycles, primary production and water quality status. The model has then been used to analyze the effects of different scenarios of loading from the drainage basin, and to solve the inverse problem of the identification of Maximum Permissible Load that is compatible with the predefined Water Quality Target. Other applications include the integration of the model with a model for the growth and population dynamic of clams, and the identification of economically efficient and ecologically sound policies for exploitation of this renewable resource, in agreement with paradigms from sustainable developments. Finally, the model has been modified, and applied to derive a contribution to the evaluation of effects of multiple temporary closures of lagoon inlets on the water quality of the lagoon.