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<br />sediment load data base is supplemented with sediment samples collected in the <br />early 1950s and again sporadically throughout the 1970s and into the 1980s. The <br />more recent sediment load measurements have been collected only once a month <br />or a few times a year. Incidental sediment load measurements were also made in <br />1983 by the USGS (Elliott, et al. 1984) and in 1989 by RCI (1991). <br /> <br />Several analyses of the Little Snake River sediment load have been <br />attempted including Andrews (1978 and 1986), O'Brien (1984 and 1987), Elliott, <br />et al. (1984a and 1984b), Koch and Smillie (1984) and RCI (1991). All these <br />analyses have included use of sediment rating curves (sediment discharge <br />expressed as function of water discharge). Only Andrews (1978) and O'Brien <br />(1987) analyzed the original Lily Gage sediment load data to derive sediment rating <br />curves. These two analyses were not consistent in the use of the data base nor <br />was the same functional relationship derived between sediment discharge and <br />water discharge. All the other studies applied the rating curves derived by <br />Andrews (1978) and O'Brien (1987) in some form. In addition, none of the <br />studies examined all the available data for sediment load at Lily which now covers <br />a 40 year period. Missing from these analyses is a consistent application of the <br />sediment rating curve, projection of trends in the stream flow data, an <br />investigation of sediment load variation by size fraction, and projection of trends in <br />the sediment rating curves. <br /> <br />The Lily Gage sediment load analyses are summarized in Table 4. Andrews <br />(1978) computed a mean annual suspended sediment load for the Lily Gage of 1.3 <br />million tons. A total sediment load of 1.4 million tons per year was based on the <br />sum of the suspended load and a computed bed load of 70,000 tons per year <br />based on the Meyer-Peter and Muller bedload equation. Andrews (1978) did not <br />provide the Lily Gage sediment rating curve in his publication. O'Brien (1984, <br />1987) computed the mean annual sediment load on the basis of the measured load <br /> <br />20 <br />