Lifting of biogenic compounds by a riverbed from a municipal drainage basin on a day scale

Abstract

Urban river is the object of very dynamic hydrochemical changes. It was decided to trace the variability of physicochemical elements within 24-hour. One of the rivers in ŁÓdŹ – Olechówka – was selected for research, where, having knowledge from previous research, two measurement-control points were established: first located in the middle course of the river (on its quasi-natural fragment), second at its mouth to the recipient. Between these points, the Olechówka River catchment gains significantly on urbanization. A measurement series during 24-hour was carried out at each of the points, during which in situ measurements Q, T, pH, SEC and O2 were taken every 1 hour and water samples were taken for the analytical determinations NO3-, PO43-, NH4+, TN, TP and Susp. With relatively stable hydrological conditions, a twenty-four hour cycle of changes in nutrient concentrations was observed, whose maxima occur during the night hours.