Ths study was carried out between March 2011 and February 2012 on Değirmendere Stream in order to determine the water
quality of the stream, and to investigate the environmental quality and the applicability of both the Biological Monitoring Working
Party (BMWP; Original, Spanish, Hungarian, Czech, and Polish versions) and Average Score Per Taxon (ASPT; Original, Hungarian,
and Czech versions) indices. Th biotic and diversity indices were applied using the ASTERICS softare program. As a result, a total of
59 taxa were detected: 4 taxa from Gastropoda, 1 taxon from Bivalvia, 1 taxon from Oligochaeta, 1 taxon from Hirudinea, 2 taxa from
Crustacea, and 50 taxa from Insecta. Th water quality of Değirmendere Stream was found to be unpolluted/slightly polluted according
to the physicochemical data and the diffrent versions of the BMWP and ASPT. However, the score values of the diffrent versions of the
BMWP were diffrent from each other because the versions of the BMWP were adapted based on the geological and ecological features
of their source countries. Th results of this study suggest that there is still a need for much intensive investigation and further testing of
the effctiveness of the BMWP and ASPT indices for use in the streams of Turkey. Th fidings also strongly indicate that these indices
should be adapted based on the geomorphological and environmental features of Turkey