NITROGEN REMOVAL IN A FRESHWATER RIPARIAN WETLAND: AN EXAMPLE FROM ITALIAN LOWLAND SPRING

Groundwater flow and nitrogen dynamics were investigated in a riparian area richarged with groundwater having a high nitrate levels (3 - 35 mg/l N-NO3). The results collected during a two years period (2002-2003) indicated a drastic reduction of N-NO3 concentrations at only 5-10 m from the crop field within the riparian strip. The comparison of groundwater nitrate and chloride trends at different depths and distance from the crop field to the stream suggested the importance of biological processes in the nitrogen removal. The hydrological and morphological features of the studied area provide conditions conducive to denitrification.