| Abstract: | AbstractFlushing time (Tf) is an important factor which determines the hydrological, ecological and chemical functioning of lakes. However, it has never been calculated on the basis of underground supply for Polish Lakes. Due to their high altitudes, the lakes in question constitute a distinctive group among the ??czna-W?odawa Lakes. They are located in the borderland of the Cretaceous Che?m Hills (part of the Polish Uplands) and Polish Lowland. The quantity of the underground water supply was one of the key factors which make these lakes so distinctive. During periods of low precipitation, water shortages occurred in the lakes, especially Pniówno and Syczyńskie. The ??czna-W?odawa Lakes are commonly distinguished, among other Polish water bodies, as super-passive due to their water flushing time (>10 years). However, the average flushing time of the water in lakes Tarnowskie, Chuteckie, Pniówno and Syczyńskie, based on the underground supply, amounted to 606, 211, 54 and 79 days, respectively. The territorial conditions (e.g. geologic structure of catchment areas or thickness of unsaturated and saturated zones) were the most important factors that determined seasonal fluctuations of the supply to the lakes. |
