Field studies were conducted at the intakes of three Tennessee Valley Authority electric power plants to determine whether intake design is a feasible means of mitigating effects on zooplankton by minimizing the quantity entrained. Three intake designs were evaluated: one with a shallow skimmer wall, one with a deep skimmer wall, and one with no skimmer wall. Many sample sets from these studies were highly variable because of inadequate sample replication, thus precluding the use of statistical tests on some of the data. Where possible, an analysis of variance and a Student, Newman, Keuls multiple range test were computed and tested at the 0.05 level. Several studies indicated possible differences between day and night in the quantity of zooplankton entrained. The greater quantities entrained at night were related to a greater abundance in the source water body at night rather than to intake design. These results indicate that time-of-day differences might be used to mitigate effects on zooplankton at some intakes if the intake could be operated to require less cooling water when concentrations were greatest. None of these studies indicated that the intake designs studied minimized the quantity of zooplankton entrained because the quantities in the intake canals were similar to the quantities in the source water body. (ERA citation 08:045998)