Future projections of nutrient fluxes to Lake Mälaren / Framtida projektioner av närsaltflöden till Mälaren
Two climate projections are used as forcing data in a hydrological model for the Lake Mälaren catchment, in order to evaluate the expected impact on nutrient fluxes (nitrogen and phosphorus) into the lake. Lake Mälaren comprises a large lake system, discharging into the Baltic Sea through the city of Stockholm, Sweden. Being a major fresh-water source, the lake is a potentially vulnerable resource under climate change impacts on e.g. inflow of nutrients, which is a main factor for drinking water production. The two projections both point at a future increase of temperature and precipitation and a decrease of snow cover, although the level of change differs somewhat. According to the model results, these changes will increase both nutrient concentrations in the catchment and the inflow to Lake Mälaren, the latter sometimes by a significant fraction of today’s inflow.