CHANGES GROUND WATER LEVELS AND WATER STORAGES CHOSEN FOREST HABITATS OCCURRENCE IN CATCHMENT OF THE NIESÓB RIVER

The paper presents the results of the researches carried out in three hydrological years 2002/2003, 2003/2004 and 2009/2010 of a different precipitation sums. The researches were carried out at catchment of water pond number one, located at Wielisławice Forestry of Siemianice Experimental Farm. The area of investigated catchment of pond number one is about 7.5 ha and its forestation totals 100%. It is situated in a part of Niesób catchment – left-side tributary of Prosna River. In the investigated catchment the predominant fresh habitats spreading through 98% area. Moist mixed broadleaved forest is located at the west part of pond. Proper podzols are predominant in soil cover analysed catchment and to a little extent there are muckous soils. Whereas predominant soil textural group there is loamy sand. The researches indicates that the decrease of water storages in all of the analysed habitats and was from 4 mm in fresh mixed coniferous forest to 18 mm in moist mixed broadleaved forest in a dry 2004/2005 hydrological year. Whereas an increase of water storages was observed in these forest habitats in the next two hydrological years. The highest fluctuations – from 63 mm in fresh mixed coniferous forest to 82 mm in moist mixed broadleaved forest were observed in wet 2009/2010 hydrological year. The researchers also showed that changes of water storages in analysed soil of forest habitat, in winter and summer hydrological half-year was connected to the groundwater levels in these habitats. The coefficient correlation was 0.95 and this relationship was significant at α = 0.01 level