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<br />l:\AnC't <br />J'JJv <br /> <br />Dominant Discharge <br />The long-time 1915 to 1975 dominant discharge was estimated to be <br />6,930 ft3/sec, which is equivalent to a 2-year flood peak as determined <br />from a flood flow frequency analysis for the Overton gage (Pemberton, <br />1977). The "dominant discharge" is usually considered to be the bank <br />full discharge or that peak discharge having a recurrence interval of <br /> <br />approximately 2 years (Bureau of Reclamation, 1973). <br /> <br /> <br />Channel Width ~~~, <br />~~ .~~, <br />Channel widths in the vicinity of Overtofi'ba'se~pon 1971 aerial- photo- <br />,... .....,. "> <br />r ,,~ <br />graphs ar~ about 1,000 to 1,200 fee1f' Us~, ~$ the Blench equation for <br /> <br />regime width analysis incorporat~~ 'the ~G~inate discharge of 6,930 ft3/sec <br />^. . ~ . <br />gave an estimated width of 91(' feet, ~'relatively close agreement with <br />r' / <br />the widths estimated fro~~e~~~uSt 1971 aerial photographs (Pemberton, <br /> <br />1977). ~ <br /> <br />~! <br />,'" 1 <br /> <br />Effects on Habitats <br /> <br />According to Fish and Wildlife Service aerial surveys, spring crane <br />utilization of the Platte correlates well to these points of flow <br /> <br />diversion and return. For example, on April 7, 1977, 8,184 cranes <br /> <br /> <br />were counted from Chapman west to CNPP&ID's Johnson Return while only <br /> <br />one crane was observed from upstream of the diversion return west to <br /> <br />Brady. (Note: This was an index count and was not designed to count <br /> <br />the majority of the cranes. At the time of the count, roughly 250,000 <br />'1 <br />cranes were in the area, but most had left the river at the time of <br /> <br />, <br />