Impact of thermal wastes of Ignalina NPP upon the hydrothermal behavior of lake Drukshiai

The summarised data on subdivision of lake Drukshiai to three different areas according to nature of hydrothermical processes are presented. Around the site of spread of heated water of NPP the dilution field amounting 10 percent of lake's area is formed. The dynamical behaviour of this field is determined by amount of wasted heat and shape of bottom. The shallow well mixed south part of lake is not effected by wasted heat. Due to the wasting of nutrients to this area transparency of water is lower. The main deep part of the lake is stratified with well expressed seasonal distribution of temperature. Sun radiation and wind stresses are the main factors having influence upon the hydrothermical structure in the latter two areas of the lake. The probable temperature distribution is also presented. (author). 2 refs., 3 figs