Proposal for Monitoring and Research Demonstration (2)

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The general monitoring component focuses on collecting cross sections of the river and examining serial aerial photography (aerial photographs are expected to be obtained as a separate contract). Measurements at these cross sections include changes in channel topography, vegetation, and bed material grain size. These measurements will provide a baseline of information regarding the natural variability present in the system upstream of the treated area and in the untreated reach, and allow comparisons to be made to downstream sections and the treated reach. These cross sections are somewhat generalized but are defined from high bank to high bank and include all channels. Cross sections include the area upstream of the treated area, within the treated area of Cottonwood Ranch, and downstream of the treated area. The general monitoring component will include eight cross-sections: two upstream, the three gaging sites, and three sites downstream of the study section (Fig 1). 5ome of these cross-sections may be coincident with existing sections put in place by the Bureau of Reclamation and Nebraska Public Power District. It is anticipated that a systematic sample, of potential cross-sections will be identified for the system wide monitoring activities. We will attempt to include the above eight cross-sections in that sample. Thus, some or all of these cross sections will ultimately be part of the generalized monitoring scheme employed by PRESP's adaptive management of the Big Bend area of Nebraska. The intensive research component will focus on collecting data sets with fine spatial resolution on the two Platte River channels around island A, one of which will have vegetation removed and the other of which will not be modified. The intensive research component is located entirely within the two channels shown in Figure 2. Data collection will consist of detailed topographic surveying, bed and bank sampling of grain size, observations of in-channel and bank vegetation, and ground photography along the northern treated channel and the southern untreated channel (Fig. 2). These channels are similar in size, and should allow us to separate those channel effects, which are associated with normal variability, with those changes that are specifically produced by the cleazing. General Monitoriniz A series of eight cross-sections will be selected systematically (as a part of the system wide sample) within and bracketing the Cottonwood Ranch Property. These are the same cross section anticipated for use above in Section 1, Monitoring Proposal. Each section will be periodically resurveyed and re-photographed at pre-determined intervals (4-6 times per year under pre-determined flow conditions) to document changes in bed elevation and the condition of banks and vegetation on islands and adjacent to the channel. Across these sections bed material samples will be collected to document potential changes in grain-size distribution resulting from clearing activities. At all three gage sections and immediately downstream of the study area approximately 10 bed material samples will be taken at each section and dry sieved individually to document cross-channel variability in grain size using standard field and laboratory techniques (Edwards and Glysson, 1988 and Guy, 1969). At the remaining four cross- sections the 10 bed material samples taken at each section will be composited. Thus, 44 bed material samples will be obtained during each site visit giving a total of between 176 and 264 bed material samples in the first year for the general monitoring component. Page 9 of 15