Krenologia obszarów młodoglacjalnych na przykładzie Pojezierza Lubuskiego – przegląd badań

The Polish Lowland is an area with rare and relatively poorly studied springs. The present paper review results of recent studies on springs, their hydrology and environments on Lubuskie Lakeland (5.200 km2) in western part of the Polish Lowland. This area contains over 1,000 springs and seepages outflowing from porous sediments. Most of them are related to thick Pleistocene sediments containing several groundwater bearing layers, which are cut by deep subglacial channels (tunnel valleys). The spring density index is the highest in catchment of the Gryżynka River, with up to 4.8 individual springs and seepages per 1 km2. The most common in the Lubuskie Lakeland are seepages (65%), descending and hillslope outflows. Their water discharge varies from < 0.001 to 50 000 dm3/s. Hydrochemistry of spring waters is dominated by calcium and bicarbonate ions, as well as high concentrations of iron and manganese. Due to the lack of a surface insulation layer, contaminants (various forms of nitrogen) easily migrate to groundwater. Generally, the spring waters have good quality. Moreover continuous observations of the water surface levels in spring supplied water bodies revealed daily fluctuations, which are likely due to evapotranspiration and changes of the filtration coefficient in hyporheic zone.