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 Fetot. 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.