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Key Ecosystem Service: Drinking Water Supply.

Main objectives of Ecotwin:  Short-term forecasts of water temperature and thermal dynamics in the Görväln sub-basin and Long-term water quality simulations to assess how climate change may alter water quality.

Main challenges: 

•    Climate change and water temperature: Increasing temperatures, changing stratification and altered seasonal patterns may affect water quality and drinking-water treatment.
•    Algal blooms and microbiological risks: Warmer temperatures and changed stratification may increase algal blooms, toxins and the occurrence of new microbiological risks.
•    Chemical contaminants: PFAS, pharmaceuticals, pesticides and other contaminants from wastewater, industry and diffuse sources pose risks to drinking-water quality.
•    NOM and water quality: Climate change may increase NOM concentrations and alter its composition, with potential impacts on drinking-water treatment.
•    Pollution sources and pathways: The large catchment contains many potential pollution sources. Better understanding of water origin, flow direction and contaminant transport is needed to identify risks to the drinking-water intakes.
•    Complex lake dynamics: The size and complexity of Mälaren make it difficult to predict water flow, stratification and the transport, degradation and retention of contaminants.
•    Extreme events: Heavy rainfall and wastewater overflows may increase short-term loads of microbiological and chemical contaminants.
•    Saltwater intrusion: Potential future saltwater intrusion from the Baltic Sea may pose an additional risk to freshwater quality.