The estimated nutrient load has been decreasing due to the closure of several sources, resulting in improvement in the status of the lake, indicated, for example, by a slight decrease in chlorophyll. During the recent very rainy years, surface water run-off from the adjacent areas slightly increased nutrient and chlorophyll concentrations, and decreased water transparency (Secchi depth). On the Finnish side, the Juustilanjoki Basin includes the Mustajoki River, the catchment of the KSrkjarvi River, and part of the Saimaa Canal,19 including the Soskuanjoki River.