The objective is to simulate catchment-scale effects of constructed wetlands in the target areas. The simulations with catchment-scale models SWAT and VIHMA will show many and how large areas of constructed wetlands would be needed to substantially reduce agricultural nutrient loading. Simulations are made by Finnish Environment Institute (SYKE).
Two of the target catchments (Jokioinen and Lieto) entail study sites. Thus, coupling of the results from studies and model simulations will give insight on how much of the agricultural phosphorous loading could be reduced if such chemically boosted, effective systems would be made more than just these experimental ones.
The economical assessments will also be made to assess the cost-efficiency of wetlands in at least one of the target catchments. This work will be started in a 30-km2 catchment near Lahden Vesijärvi, because plenty of useful background data (e.g. a general plan of wetland establishment) from that area is available. Moreover, the local lake protection foundation (Vesijärvisäätiö) is strongly promoting constructed wetlands in the area, which makes the actual implementation of the planned wetlands more realistic.The economical assessments are made by MTT Agrifood Research Finland.
Puustinen, M., Turtola, E., Kukkonen, M., Koskiaho, J., Linjama, J., Niinioja, R., Tattari, S. (2010). VIHMA—A tool for allocation of measures to control erosion and nutrient loading from Finnish agricultural catchments. Agriculture, Ecosystems and Environment 138(34): 306–317.