ABSTRACT
A recently developed distributed watershed model VMod was applied to the Nummenjoki catchment, a part of the Karjaanjoki catchment area in southern Finland. The waters from the catchment flow to Lake Lohjanjärvi that has an eutrophication problem, at least partly caused by non-point source loading. The targets of the model application were to provide daily values for the nutrient loads that discharge to Lake Lohjanjarvi from the modeled catchment, and to provide a tool for estimating the possibilities to reduce the non-point source loads by land use management actions, such as establishment of buffer and riparian zones, establishment of wetland areas, and modification of agricultural practices. Computed results were compared to the measurements and results of a conceptual hydrological model (WSFS), regression leaching models, and field scale nutrient leaching model (VIHTA). Results show good agreement between measured and computed values of river flows and nutrient loads.
