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2) Bed Bank Sediment Sampling- The procedures for measuring bed sediment are taken from <br />Edwards and Glysson, 1999. The type of bed material sediment sampler selected for use is a <br />function of the size of the bed sediment measured and the depth and velocity of the river <br />considered. The Platte River can be safely waded during most months of a typical water year. <br />Previous experience has shown it is practical to do wading bed material sampling in the Platte <br />River. The sampler used consists of a steel cylinder 7 centimeters in diameter and 20 <br />centimeters in length welded to a steel pipe 155 centimeters long. <br />The general procedure for sampling with this sampler involves dividing the cross section into a <br />series of equally spaced increments or verticals. A sufficient number of verticals should be <br />sampled as to provide a representative statistical population. Previous sampling in this reach of <br />the Platte River indicates that there is a great deal of variability in the sizes of bed material <br />sampled along a section. We have calculated the number of samples (n) needed to characterize <br />the mean grain size given the standard deviation of a sample from this population. Based on this <br />data set we have computed that between 10 and 15 samples should provide a compromise <br />between sampling practicality and statistical confidence. Given the bank material is generally <br />more homogeneous than the bed material fewer of these samples are needed. Two samples taken <br />from each bank, above bankfull stage, along the section should provide a representative <br />population. <br />The cross-section will be divided into equally spaced increments to encompass the 15 samples. <br />At each increment the sampler is plunged into the bed of the river until the can portion of the <br />sampler is filled with sediment. Sample depths are 2 inches in order to provide similar data to <br />the BM54 sampler used at bridge sections and to sample bed material that is most readily <br />available for transport. The sample is then transferred to a sample bag that is labeled with the <br />sampled section, sample number, as well as the date and time the sample was taken. Care must <br />be taken to transfer the entire sample to the sample bag with special attention not to lose any of <br />the fine material. The procedure is identical for bank sampling. <br />The samples are analyzed by dry sieving to determine their mechanical composition. Each <br />sample is dried and weighed to determine total weight. The sample is placed in a sieve stack <br />with 1/2 phi gradations and agitated for 25 minutes using a Rotap. The weight of material <br />retained on each sieve is recarded after transferring the material to a tared dish. The process is <br />repeated for every sieve in the stacks to ultimately yield the grain-size distribution for that <br />sample (Guy, 1969). <br />3) Ground photography - Photo stations are identified as metal USGS bench marks set in 18 <br />inches of concrete. Photo stations are located on each bank of cross sections. Photographs are <br />taken upstream, downstream, and cross-stream to document the cross section and the condition <br />of the banks upstream and downstream of the cross section. Photographs are taken with 4x5 or <br />35mm film cameras or digital cameras with a minimum resolution of 1712 X 1368 pixels. Each <br />photo requires the following information: bench mark identification, date, time, film type, lens, <br />azimuth, and any remarks needed. <br />6