Summary:

To determine the influence of suspension brought to the Nysa Łużycka River , an experiment was carried out involving a controlled discharge of mine waters to the Miedzianka River with the maintenance of the total concentration of suspension not exceeding the threshold value of 30 mg/l. The study concerned the qualitative and quantitative changeability of introduced load of suspension in the river section of approximately 110 km along 15 profiles of The Nysa Łużycka River. The study included the Nysa Łużycka sector from Sienawka to Łęknica. Developed no-mograms of discharge time worked out for data from the multiyear 1991-2008 comprised the basis for establishing the discharge time of the analysed sector of the Nysa Łużycka River which in turn determines the sampling of the river waters. The studies were conducted in the zones of low and high stream discharges. It was found that water discharged from mine to the Nysa Łużycka River after its treatment in highly efficient sewage treatment plants includes suspension of low sedimentation whose quantitative volume changes in the receiver are conditioned only by the process of dilution. The concentration of suspension which is maintained by the Nysa Łużycka River at low and mean discharges, above and below the impact area of the mine, remains at a very good level namely below 25 mg/l.