Objectives of this investigation were to determine the quantity and quality of influent in bays or breakwater areas of Bear Lake, Utah-Idaho, and to appraise biological responses to water quality of the bays. Three partially completed studies disclosed the importance of the median grain size of sediments, contents of silt and clay and organic matter, the velocity of currents, and concentration of oxygen near the bottom. The results were subjected to ordination analyses. The structure of communities was influenced by environmental conditions. The median grain size of 0.20 mm is of critical importance for the distribution of benthic invertebrates. The continuum of some chironomids was indicative of the community type and environment. Only three species of chironomids, Tanytarsus A, Polypedilum digitifer, and Tendipes, were present in numbers sufficient to be utilized in production studies. The density of Tanytarsus was indirectly related to silt and clay and organic matter content of the bottom. (WRSIC abstract)