This study compares the sensitivity of biological and chemical parameters for monitoring water quality, examines several methods of analyzing diversity of the aquatic organisms and attempts to assess water quality in the three streams investigated. The Cairns-Dickson DI_T diversity index was applied to two trophic levels of aquatic organisms and the results were compared to ascertain whether this diversity index is applicable to all levels of the trophic\structure or of greater use for a particular level. Two diversity indices, Cairns-Dickson DI_T and Wilhm-Dorris d̅, were used to analyze the same component of the biological community and the results of these two indices were compared. A correlation test was performed among chemical and biological data and among chemical parameters. / Master of Science