The model system STOFFBILANZ is a complex tool for modelling water and substance fluxes in catchment areas, which we are continuously developing. Within the framework of the modelling, the origin and quantity of nutrient (N, P) and sediment inputs to rivers, lakes and groundwater are recorded.
The methodology for nutrient balancing must take into account inputs from point and diffuse sources via different transfer pathways as well as retention. Point sources are domestic, municipal, industrial and agricultural wastewater and precipitation water discharges that can be located at specific points. Diffuse sources include non-point source substance inputs that are realised via underground and surface runoff paths or atmospheric deposition. STOFFBILANZ is a model developed for the mesoscale and mediates between large-scale and small-scale methods. A detailed model description is available here.
The web application STOFFBILANZ-Viewer publishes the results of modelling work on soil erosion by water and sediment, nitrogen and phosphorus inputs in the Saxon river basins, which has been carried out continuously for many years using the STOFFBILANZ model.
The web-based user interface combines user-friendliness, technical aspects and requirements for river basin management. The web service consists of various modules (including maps, statistics, measuring points) for the visualisation of input data and modelling results as well as their analysis and export (shape-files). For a restricted group of users with login access, raster data can also be retrieved in geotiff format.
The model is used to calculate actual conditions, management scenarios, potential effects of measures and the derivation and testing of reduction options for achieving environmental quality objectives and meeting environmental quality standards for substance inputs into groundwater and surface waters. In Saxony, STOFFBILANZ is mainly used in connection with the implementation of the EU Water Framework Directive (WFD), the Fertiliser Ordinance and the obligations to achieve the marine protection goals. Here, the focus is on measures in the area of urban water management and agri-environmental measures in agriculture.