Material Flow Modeling
Modeling of emissions is based on catchment hydrological modeling. It is done with the software STORM. For the calculation of annual nutrient loads, a balance approach is used. It uses concentrations depending on different land uses. A distinction is made between sealed and unsealed surfaces (see Figure 1). For unsealed surfaces concentration values for the different runoff components; surface runoff, interflow and base flow are determined. For sealed areas only the surface runoff will be applied. For determining concentrations values from; data bases, literature, analysis and surveys are used.
The used balance approach is a simplification of material flow processes when compared to reality. The validity of the results is therefore limited. However, the method is very well suited for an estimate of annual loads and average concentrations.
The results can be displayed either in tabular form or summarized upon export to excel.