THE THERMAL AND OXYGEN RELATIONSHIP AND WATER DYNAMICS OF THE SURFACE WATER LAYER IN THE KONIN HEATED LAKES ECOSYSTEM

Analyses were performed on the impact of the discharge of post-cooling waters on the hydrological and thermal and oxygen conditions in the canals and two lakes that are part of the Konin (Poland) and Patnow (Poland) power plant cooling systems. Lake Lichenskie (Poland) received the greatest quantity of post-cooling water and was the most intensely heated lake in the system (up to 27C). Water exchange in the lake occurred in a period from three to five days. Lake Slesinskie (Poland) remained the coolest lake in the system (surface water temperature reached 25C), while the water retention period was shorter only in summer (up to seven days). The oxygen content in the surface waters of the ecosystem did not fall below 7.5 mg O sub(2)/l (80% saturation). The short water retention time in the Konin ecosystem meant that lakes exhibited characterize typical of lotic system, at least in the surface layers