Glebokie Lake in Szczecin after hydrotechnical regulations

Water quality of the Glebokie Lake in Szczecin (NW-Poland) was studied in years 2012-2014. Glebokie Lake is a reservoir with a negative water balance related to the location draining groundwater drinking water intake for Szczecin agglomeration. In 2004 hydrotechnical regulations were conducted aimed at maintaining a constant amount of water in the lake, which involved a temporary feeding Glebokie Lake with Gunica River waters. In order to determine the hydrochemical status of the Lake waters and the factors shaping water quality - 19 water quality indices within 25 months were measured: temperature, pH and water oxygen status, nutrients (N, P) and ionic macrocomponents and Fe_tot. Trophic status of the lake waters using the Carlson criteria was defined. On the basis of chemometric analysis of measurement data (CA, PCA/FA and DA) we established that statistically significant factors affecting water quality in the study period were: seasonal (the climatic seasons) changes in the biological processes activity, periodical (in April and November) waters inflows from the Gunica River, anthropopressure in during swimming season and the coagulant (FeSO₄) presence in the ecosystem. The possibility of applying the chemometric techniques to interpret measurement data in the lake type like Glebokie Lake with a small amount of data has been shown.