The impact of the groundwater outflow on the runoff of the Nida River at Pinczow

Abstract

Values of mean annual baseflow rates for Nida River at Pińczów have been estimated and analysed for water years 1951-1998. The analysis has shown that the base runoff from groundwater contributes significantly to the river discharge. The long-term average of annual baseflow rate for the period 1951-1998 is estimated to be 11.3 m³/s which is about 62 % of the total annual runoff. Additionally it was proved that the zone of groundwater contributing to the river runoff does not coincide with the watershed boundaries. The boundaries of the zone within which contacts of groundwater and river take place is difficult to be strictly estimated due to heterogeneity of existing aquifers. However the analysis has shown that the river runoff depends highly on the groundwater resources that are in direct contacts with surface waters