ASSESSMENT OF TROPHIC STATE OF INLAND WATER (THE CASE OF THE SOLA CASCADE DAM RESERVOIRS)

The objective of the study was to assess the trophic state of water in the hydrographic system of the Sola cascade, situated in the Carpathian region in southern Poland. Analyses included inflowing and retained water in dam reservoirs: Tresna, Porabka and Czaniec. The level of eutrophication of water was estimated basing on its physicochemical parameters. Out of all methods used in determining the trophic state, the selected methods included the norms determined in the Polish regulations, the Neverova-Dziopak index (ITS - Index of Trophical State) and the Carlson index (TSI - Trophic State Index). Analyses of data from years 2007-2009 showed that water quality reflected characteristic parameters for mesotrophy and eutrophy. Unfavorable trophic state concerned almost all waters that were studied, including waters of the lowest reservoir of the cascade - Czaniec reservoir, which is part of the municipal water supply system. That emphasizes the need for protection of the catchment of the cascade with regards to reduction of contamination load discharged to surface waters.