Urban stream Osówka in Szczecin : how efficiently as possible should the variability of the stream water quality be studied along the road of runoff in time?

The water quality of the stream Osówka in the NW part of the Szczecin city was studied. Water samples were collected in four seasons of 2014 – January, April, July and October in 6 sampling stations, from station near the source of the stream – to inflow of Osówka stream water to the lake Rusalka. 20 selected water chemistry indices were measured. The aim of discernment variability of water quality along stream runoff path during studied period chemometric procedures were conducted: cluster analysis (CA), calculations of linear regression equation y_i=y_i+∑⁶_j=1α_jS_j+∑⁴_k=1ß_kT_k+SEE for selected water quality indices (y_i), where S_j and T_k – are sampling stations and sampling terms numbers – respectively, and factor analysis (FA). It has been shown significant variability of Osówka water quality along the runoff path and established what parameters characterizing the variability of stream water chemistry should be examined in the places of indicated sampling stations – the same as in the studies – the quantities of terms of sampling in 4 consecutive seasons.