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2. Platte River H alt,**"_ thmebt Characteristics <br />The objective of the proposed task for sediment transport is to describe <br />how the Platte River channel will respond under various flow scenarios <br />and sediment yields. The work will explain the relationship between <br />sediment transport and the chi *J,Vo metry n the Platte River bet en <br />N Witte` and Chapman, - Nebraska. Changes -I mont <br />result #ro +bperationai changed of <br />the, North ;Rlette graiecte, ior colorado -li4 'Aompscn projects. <br />Previously., researchers-have reported on the historical trends in the <br />channel morphology of the Platte. These reports were reviewed in the <br />Reclamation study entitled "Platte River Channel Characteristics in the <br />Big Bend Reach," April 1988. The results of this s: , ate Uhat <br />the -Platsts. exparisnced at decrease in sediment supply as mainsteni <br />resszvQa�e,we�s.ettuced. This reduction in historical sediment <br />loads was found to be a major cause of channel narrow;�ng. Prd**ntrly, <br />the -VI tt* Appgrbrs to be" in a state of quasi-equilibrfum in terms of <br />sediment transport between overtiw and Grand Island, Nebraska, as <br />sediment inflow to this reach is essentially equal to sediment outflow. <br />This quasi - equilibrium shtrt -ld i �atleee the sediment 'sAKpVly._toq�,:the <br />Platte liv ` -is changed or the flows between 1,000 cfs and 10,000 ifs <br />are­..*,J4m4,J4cantly changed to alter the effective transport of sediment <br />through the Patte River. <br />Threatened and endangered species needs are being defined by the habitat <br />that the species are currently using on the North Platte, South Platte, <br />and Platte Rivers. These habitats are quantified and qualified by the <br />physical characteristics that describe the habitat. The physical <br />habitat characteristics have been described in various workshops and <br />publications. <br />0 27 <br />The work effort to develop a sediment transport analysis for use in <br />project evaluation was begun during the Prairie Bend Unit study in <br />. <br />fiscal year 1989.. Collection of sediment data continued in 1990 under <br />this evaluation and is expected to continue in later fiscal years as <br />funding becomes available. A Plan of Study titled "Platte River <br />Hydraulic and Sediment Characteristics" was in 1989 as part of the <br />Prairie Bend Unit investigation. The 1989 plan is being followed in <br />this evaluation. <br />The details of this work effort can be found there along with the <br />original schedule for doing this work. To date, much of the field data <br />collection work has been accomplished, and the study will continue when <br />funding becomes available. <br />3. Species Habitat Needs <br />Threatened and endangered species needs are being defined by the habitat <br />that the species are currently using on the North Platte, South Platte, <br />and Platte Rivers. These habitats are quantified and qualified by the <br />physical characteristics that describe the habitat. The physical <br />habitat characteristics have been described in various workshops and <br />publications. <br />0 27 <br />