The usefulness of various indices in the assessment of water quality of a lowland river

In the studies carried out at the upper stretch of the Liwiec River (the Bug River tributary) the following aspects were analyzed: chosen chemical parameters of water, the content of N, P and Corg in bottom sediments, the taxonomic composition of invertebrate macrofauna, the taxonomic composition of macrophytes and the coverage of the bottom with hydrophytes. Chemical and biological water quality assessment (BMWP-PL and MIR indices) was performed. Correlations between chosen chemical water parameters and bottom sediments parameters and the values of biological indices were established. Our results confirmed that the macrophyte index is an appropriate indicator for assessing the degree of river eutrophication. It seems that the values of MIR index used to asses water quality of a lowland river should be revised. Thus, the index based on macroinvertabrates is currently more suitable for the assessment of a lowland river water quality.