Tomi Dufva: Illuminate lakes

The main problems in many Finnish lakes are eutrophication and excessive plant growth result- ing from nutrient loading. After the point source nutrient loading from industry and communities was significantly reduced in the 1970s and 80s by building waste water treatment plants, the focus shifted to diffuse loading from agriculture, forest- ry, peat production and scattered rural settlements. Despite actions to reduce diffuse loading, the wa- ter quality is still moderate, poor or even bad in many lakes. The goal of river basin action plans made according to EU water framework directive is to achieve good ecological state in all the lakes and rivers by 2015 or at the latest 2027. This re- quires actions from everybody, since there is no one source to blame.
Installation displays the phosphorus and nitro- gen concentration of four finnish lakes (Inari, Päijänne, Saarijärvi and Lahden Vesijärvi) since 1976. Based on measurements we have calculated the annual mean, the mean of growth period and the minimum and maximum values. The data is collected from the environmental administrations Oiva-service. The numerical values are tranformed to colors which represent the water quality in the lake.