WPŁYW NIŻÓWEK HYDROGEOLOGICZNYCH I ODWODNIEŃ GÓRNICZYCH NA SYSTEMY WODONOŚNE POJEZIERZA GNIEŹNIEŃSKIEGO

Abstract

IMPACT OF HYDROGEOLOGICAL LOW FLOWS AND GROUNDWATER DRAINAGE BY LIGNITE OPEN CAST MINE ON AQUIFER SYSTEMS OF GNIEZNO LAKELAND

Abstract. The paper presents the problem of water resources degradation in the eastern and central parts of Gniezno Lakeland, the region of lignite exploitation zone. Impact of natural and anthropogenic factors, particularly water drainage by lignite open cast mine, on water bearing systems was studied. The analysis was based on available meteorological, hydrological and hydrogeological data from the past five decades.
By correlating water gauge, piezometer data and meteorological parameters and by monitoring variability of depths of aquifers, it was discovered that the decrease of water levels within the entire area was caused primarily by climatic factors. The analysis showed that fluctuations of depths of aquifers in the eastern part of Gniezno Lakeland remain within standard parameters for this region with the exception of aquifers located in the system of the Ostrowo–Gopło Canal. The study of geological structure of this region and the response of the aquifers led to the conclusion that groundwater drainage by lignite open cast mine also contributed to the lowering of water table ordinate of lakes and groundwater reservoirs in this region. Water drainage by the lignite open cast mine created a depression cone located east of the lake system which had a considerable impact on limiting underground recharge potential of these reservoirs.