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resurveyed. While all of these sections are located downstream of the intensive research <br />reaches, 3 are located upstream of the Elm Creek Bridge and 2 below the bridge (Figure 2). <br />The sections located downstream of the Elm Creek Bridge were placed on NPPD property <br />and do not require special permissions for access. However, the three sections above the Elm <br />Creek Bridge are located on private property and permission to access that property was <br />granted by the landowners. The General Monitoring transects were surveyed and sampled in <br />approximately the same manner as the intensive sections described above. Survey lines for <br />the General sections were pre-selected in the office with GIS software and the endpoints of <br />these lines entered into the GPS data collector. The endpoints of these lines were navigated to <br />in the field and the section monumented and surveyed in the same manner as the intensive <br />sections. While the total number of bed material samples collected in the General Monitoring <br />transects is similar to the number collected in the intensive sections, 10- 15 verticals, the <br />sampling was not as intensive as a whole along the sections with multiple channels. A <br />minimum of three or four bed material samples were taken at equal intervals across each of <br />the North and South channels. It was decided that the center channel would be sampled with <br />greater intensity than the both the North and South channels because a larger proportion of <br />the flow is conveyed through this channel. We took ground photographs from the left bank of <br />the river to the right bank in a manner similax to that described above for the intensive <br />sections. <br />D. Stream Gage Installation and Operation <br />A streamflow gaging station, 06768035 Platte River Middle Channel, Cottonwood Ranch, <br />Near Elm Creek, NE, was installed along the middle channel of the Platte River at the <br />downstream end of the Output reach in May 2001. The real time stage and discharge data for <br />this gage can be accessed through the Internet (http://www-ne.cr.usgs.gov/rt- <br />cgi/gen_stn_pg?station=06768035). At the time of this writing over 20 discharge <br />measurements have been made. These discharge measurements define the rating curve for <br />this gage. All of the measurements up to this point have been made at low flow, less than <br />2000 cubic feet per second (cfs), so additional measurements at higher flows will be needed <br />to apply the rating over a larger range of flows. <br />E. Serial Still Photography <br />In May 2001 a conventiona135mm camera was installed to routinely (one photograph per day <br />at a set time) photograph the river within the Output reach. Interval photography is a useful <br />technique to monitor geomorphic features in river channels and identify flow patterns with <br />changes in discharge and time. Sequences of photographs can be built up over a period of <br />time to create time-lapse movies. These image sequences can assist in qualifying changes in <br />sandbar size, vegetation patterns and inundation extent as a function of time and water level. <br />Based on the level of interest generated from the one camera set up, additional cameras were <br />purchased by USGS and were installed by NPPD from different vantage points in the Output <br />and Managed reaches to document management activities and monitor potential geomorphic <br />responses. <br />4