Whether undesirable changes occur in bays, especially those formed by break-waters, was studied in Bear Lake, Utah-Idaho. The quantity of influent water was measured, the differences in quality in the bay from the lake determined, and a comparative study of any measurable biological responses possibly related to differences in water quality made. Measured water chemistry parameters did not differ from one location to another in Bear Lake. Sheltered areas, protected by bays or breakwaters, contained conditions more favorable for development of vegetation and populations of some chironomid species than areas exposed to full force of water currents. There is an apparent annual eutrophication cycle in sheltered bays.