Warning level (in swedish) 2, SwedenThe aquatic environment in lakes, watercourses and in the water around the Swedish coastline is to a large extent dependent on processes on land, not only in Sweden but also in neighboring countries.
An important environmental problem in Sweden and its surrounding seas is eutrophication, caused by excess emissions of nutrients, in particular nitrogen and phosphorus. Two important sources of these nutrients are waste water treatment plants and runoff water from agricultural land. The amount of water discharging through watercourses is also important as it is affecting currents and salinity in the sea.
We at the hydrological research unit at SMHI develop methods and tools to quantify and map sinks and sources of nutrients and the pathways of water and nutrient from land to the sea.
Modeling for better knowledge and decisions
Introducing measures to improve water quality is often costly why it is rational make well informed decisions based on high quality decision support. Such information may contain analyses of what effect various measures have on water quality both locally and downstream in the system.
Calculations of water flow and nutrient (nitrogen and phosphorus) transport and concentrations using the HYPE model are performed for the whole country of Sweden (450 000 km2) divided into more than 37 000 subbasins (S-HYPE).
The results are mainly used in the implementation of the EU Water Framework in Sweden. The results are also available for the general public at the SMHI Waterweb.
The hydrological research and development at SMHI is funded through from many different sources including national bodies and the EU. The water quality work at SMHI is also part of the HOME Water concept and the overall objective of our work is to develop tools to be used in the implementation of the EU Water Framework Directive.
The Baltic Sea in a future climate
Nutrients causing eutrophication are transported to the Baltic Sea via watercourses in all countries surrounding the sea. The contributions of the different sources of emissions vary between these countries.
To obtain a comprehensive view of source apportionment and to quantify water flow and transport of nutrients to the Baltic Sea, a model was set up for the entire Baltic Sea drainage basin. The model is also used to study how the transport of nutrients to the sea will change in a future climate.
References
Lindström, G., Pers, C.P., Rosberg, R., Strömqvist, J., Arheimer, B. 2010. Development and test of the HYPE (Hydrological Predictions for the Environment) model – A water quality model for different spatial scales. Hydrology Research 41.3-4:295-319.
