Sensitivity analysis as a tool for the implementation of a water quality regulation based on the Maximum Permissible Loads policy

This paper shows how local sensitivity analysis, in respect of the parameters which specify the boundary conditions, can be used for relating the total load of non-conservative pollutants to their distributions within a water body. The method is applied to the estimation of the Maximum Permissible Load of inorganic nitrogen in the lagoon of Venice, that is of the maximum load of nitrogen which keeps its average yearly concentration below a prescribed threshold. The use of the spatial distributions of sensitivity coefficients in order to rank the sources of pollution and to forecast the effect of a reduction in the pollution is also discussed.