Final Environmental Impact Statement Volume I, Main Text and Appendices A-J

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plovers. The low flows also limit water - oriented recreation on the river. Continuing low flows on into autumn result in frequent poor roosting conditions for cranes. The FEIS is directed, principally, at evaluating how alternative modified operating regimes would change long -term average hydrologic conditions, specifically, instream flow levels in the Platte River and reservoir levels in Lake McConaughy. In summer, river flows between 650 and 1,500 cfs at Grand Island provide full protection for terns and plovers nesting on river sandbars, aquatic organisms living in the river, river water quality, and river reaction. Flows below 800 cfs result in deterioration of habitat quality for some species, while we consider flows below 200 cfs seriously detrimental to important resources. In winter, flows in excess of 1,100 cfs are desirable to limit ice formation and thereby protect bald eagle foraging habitat in the canal and river downstream of the projects' J -2 Return. During the spring and autumn, flows above 1,700 cfs at Grand Island optimize habitat area for roosting cranes. Lake McConaughy water surface elevations between 3,240 and 3,260 feet during the summer are best for lake- oriented recreational activities. High lake levels in the spring, particularly near 3,260 feet, improve survival and production of resident fish. Higher lake levels also mean greater hydropower capacity and greater insurance against potential irrigation supply shortages caused by prolonged droughts. Results of the computer Figure ES -1. Average monthly flow at Grand Island under the simulation modeling Baseline (source: the staff) demonstrate that there is insufficient water to satisfy all these objectives all of the time. Tradeoffs have to be made between increasing the frequency of desirable flow or lake levels in one season, and decreasing the frequency of desirable levels in another. In the FEIS, the staff concludes that the preferred alternative is a basin -wide resolution wherein the licensees participate in a regional (three- state) species recovery plan. This opportunity arises from a "Cooperative Agreement for Platte River Research and Other Efforts Relating to Endangered Species Habitats Along the Central Platte River, Nebraska" (Cooperative Agreement), which was signed on July 1, 1997 by the Governors of Nebraska, Wyoming, and Colorado and by the Secretary of the Interior. The signatories to the Cooperative Agreement agreed to participate in the development and implementation of a recovery plan directed at four target species (i.e., least tern, piping plover, whooping crane, and pallid sturgeon). In addition, the Districts and the U.S. Department of the Interior (Interior) agreed to specific actions that the Districts will undertake for protection of federally listed species and their habitats and other nonlisted species. These actions, which ES -3