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to other uses. <br />Decline of sediment load from reductions in magnitude, frequency, and duration of normal <br />high flows adversely affect sediment transport from the watershed and through the river <br />system. The transport of sediment is a principle benefit of spring pulse flows in alluvial <br />rivers such as the Platte. Reservoirs, diversion dams, and irrigation canals trap sediment, <br />reducing sediment load in the river. The supply and transport of sediment through the <br />riverine system are essential to sustain the alluvial channel habitats used by federally listed <br />species, and necessary for maintenance of a diverse channel morphology. <br />Assessment of Program Impacts <br />The above sections describe the influences of water development on the habitat of the target species, <br />and efforts being made to offset those impacts. The following section identifies, by species, the <br />questions needing resolution (i.e., the basis for the Service's evaluation of Program impacts). The <br />questions are consistent with and supported by elements of the recovery plans for the target species, <br />elements of the species listing determinations, elements of the critical habitat designation, the <br />general factors of species listing /delisting expressed by Service policies, Platte River biological <br />opinions, and laws and Department of the Interior and Service regulations and policy guidance <br />pertaining to environmental planning. Species - specific tables are also attached, which identify data <br />needs correlated to the questions, and include potential sources of that data, potential methods of <br />analysis, and the time frame of data collection during the first increment. <br />I. Whooping Crane <br />A. Channel Roost Habitat: Constituent Element of Designated Critical Habitat <br />1) How do Program changesin flow management affect the immediate (i.e., daily) <br />quantity and quality of aquatic roosting habitat during migration periods? <br />2) How do Program changes in land and river flow management affect the amount, <br />quality, and spatial distribution of open - channel roosting habitat? <br />3) What effect do Program changes in river flow management (e.g., elements of the <br />Program that protect existing flows, sources and methods of water replacement, EA <br />operation) and land management have on the sustainability of channel habitat? The <br />Service will consider related questions such as: <br />a) Is the river morphology sustainable based on the available sediment supply? <br />(1) What is the long -term effect of program water management on <br />availability and transport of sediment? <br />(2) Is sediment supply in dynamic equilibrium? <br />b) How does Program water management affect riparian vegetation <br />encroachment? <br />(1) What flow regime maximizes number and areas of unobstructive bare <br />I <br />