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<br />0502 <br /> <br />A study (Pemberton, 1977) of sandbar movement was made to evaluate <br /> <br />the effects that construction of Narrows Dam would have on the reach <br /> <br />of the Platte River between Overton and Grand Island, Nebraska. The <br />study purpose was to determine if ~here would be a detrimental effect <br />to or loss of the shallow, submerged unvegetated sandbars in this 70-mile <br />reach of the Platte River. <br /> <br />, <br />Use of July 1938 and August 1971 aerial photo~~phs, gage height data <br />&v: ~. <br />at Overton, historical and computer mOd~<;~t;~a)flOW data was <br />reflected in the study conclusions. ,,/ ,\":::\;~ .' <br />,; .,I>.."V <br />( , .,:>" <br />The decrease in mean annual dis~rar.ge ~t.averton with Narrows Dam of <br />(' ':V <br />121 ft3/s to 1,029 ft3/s is~xpect~.,..)(o have little effect on open <br />channel widths. The ope~hinnel;'~dths would be controlled by the <br />, 'Y <br />dominant discharge. Little ~nge in the dominant discharge of the <br />Platte River at Overton due to Narrows Dam and Reservois is anticipated <br />with the contributing drainage area of 45,155 square miles between <br />Narrows Dam and Overton gage (Pemberton, 1977). <br /> <br />Ice jams will continue to occur with the resultin scouring action or . <br />move~ent and continual shifting of the streambed that helps maintain <br />the open channel of unvegetated sandbars (Pemberton, 1977). <br /> <br />Impacts to the Wet Meadow Complex <br />There are two "schools of though" within the ~epartment of the Interior <br />regarding the impacts of additional flow depletions on wet meadow <br /> <br />, <br />