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I I I Larval fishes in the Missouri River are dominated by freshwater drum, catostomids, cyprinids, and carp (Hergenrader, et al. 1982). Larval fish were found to be common in the drift from early May through July, Spawning areas used are along the shoreline, in backwaters, and behind channel control structures. Only limited suitable nursery areas exist in the channelized Missouri River because of high current velocity, turbulent flows, and silt and sand loads. Hergenrader, et al, (1982) found evidence that backwater areas function as nursery zones, II I I I I I I II The relative abundance of fish species in the Missouri River has changed dramatically since the channelization of the river (Hesse, et al. 1982). This is believed to be due to the changing availability of aquatic insects. Hesse, et al. (1982) contend that midchannel sandbar production has assumed a larger proportion of the total system production following a reduction in overhanging trees, snag production, and off-channel backwater production as a result of channelization, Species such as flathead chubs and plains minnows have been replaced by those species, such as emerald shiners, which rely more on zooplankton availabilities in swifter currents, According to Carter, et al, (1982), benthic densities and numbers of taxa were typically lowest in June and increased in late summer and autumn. This was attributed to a relatively stable river flow, higher water temperatures, and increased photoperiod, At other times the swift current, high turbidity, and substrate instability of the main channel of the Missouri River seriously limit the development of macroinvertebrate populations. Major colonizers are restricted to pile dikes, riprap, and a narrow zone near shore. Trichoptera, Ephemeroptera, and Diptera inhabit the dikes and Chironomidae and Oligochaeta are commonly found in depositional areas near shore (Carter, et al. 1982), I I I I ,I II I I The periphyton of the channelized Missouri River is dominated by a combination of diatoms, green algae, and blue-green algae, Bacillariophyta, Chlorophyta, and Cyanophyta are dominant forms of periphyton in the river (Farrell and Tesar 1982), Seasonal patterns of zooplankton abundance were measured by Repsys and Rogers (1982) in the vicinity of Fort Calhoun and Cooper Nuclear Stations. Fort Calhoun Nuclear Station is 90 river miles north of the project site and Cooper Nuclear Station is 24 river miles south of the site. Extensive studies of river biota have been conducted throughout this stretch of the Missouri River to evaluate the effects of the two nuclear stations. They found that the populations were characterized by relatively high microcrustacean densities from late fall to spring, with reduced populations occurring during summer and early autumn. Most of the zooplankton present in this lower portion of the river originate in the mainstem reservoirs located in the upper portions of the Missouri River. g. Terrestrial/Wetland Resources: The following information was obtained through interpretation of aerial photographs taken in March 1994, The information was verified and enhanced through a field investigation, 11