TVA tributary and mainstem reservoirs show generalized differences in morphometry, hydraulics, nutrient loads, and response to nutrient conditions. Neither type of reservoir is comparable to the natural lakes on which classical eutrophication studies have been based. The majority of published trophic state indices and standards (e.g., hypolimnetc dissolved oxygen depletion, Secchi depth, areal nutrient loading rates, in-reservoir phosphorus concentrations) are inappropriate for evaluation of the trophic status of some or all TVA reservoirs. Relative trophic state indices were developed for mainstem and tributary reservoirs using relevant potentiating and response variables. Ranking of the mainstem reservoirs is based on planktonic chlorophyll, macrophyte coverage, hydraulic retention time, reservoir area less than 5 feet deep, annual pool elevation drawdown, and Secchi depth. Ranking of the tributary reservoirs is based on planktonic chlorophyll, total phosphorus and total nitrogen weighted by the N:P ratio, and bioavailable inorganic carbon levels.