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<br />Method of Computation <br /> <br /> <br />002618 <br /> <br />others, 1965). Other suspended-sediment measurements were made periodically <br />for the Yampa River near Maybell and Little Snake River near Lily as part of <br />the National Stream Quality Assessment Network (NASQAN) program (Ficke and <br />Hawkinson, 1975). The frequency of data collection at these stations was <br />changed during the 1976 water year to a daily frequency for the Yampa River <br />near Maybell and to a weekly frequency for the Little Snake River near Lily. <br />Also, daily or monthly sediment measurements are made at several gaging <br />stations in the Yampa River subbasin as part of ongoing cooperative programs <br />(U.S. Geological Survey, 1976). <br /> <br />Estimates of mean-annual sediment loads for the 17 selected gaging <br />stations in the Yampa River basin (fig. 1) were computed using the flow- <br />duration, sedlment-transport-curve method described by Mi.ller (1951).. This <br />method Is useful when the gaging-station record of streamflows is sufficient <br />to define the frequency of occurrence of various discharges, and when <br />sediment data are limited. A sediment-transport curve relating the daily <br />suspended-sediment load and dally water discharge was developed for each of <br />the 17 stations based upon the available measurements. Similarly, a relation <br />between the computed bedload-transport rates and discharges was developed as <br />described subsequently. A total-sediment-transport. curve was determined by <br />summing the suspended-load and bedload relations. Then, the total-sedlment- <br />load relation was combined with the average-annual frequency of occurrence of <br />various discharges recorded at each gaging station to obtain the mean-annual <br />total-sediment load at that location. <br /> <br />Total-Sedlment-Load versus Discharge Relations <br /> <br /> <br />An example of how the total-sedlment-dlscharge versus water-discharge <br />relations were constructed for each of the gaging stations is illustrated In <br />figure 2. As noted previously, the total-sediment discharge was composed of <br />two parts, the suspended load which was measured and the bedload which was <br />computed. Initially, sediment-transport curves relating the measured <br />suspended load and the computed bedload to the water discharge were developed <br />separately. The suspended-sediment-discharge versus water-discharge relation <br />was determined by plotting dai ly mean suspended loads against the dai ly mean <br />discharges. A mean relation, shown by a dashed line in figure 2, was calcu- <br />lated by a least-squares linear-regression function of the log-transformed <br />data. <br /> <br />The bedload-transport-rate versus water-discharge relations were com- <br />puted by the Meyer-Peter and Mueller (1948) equation. The total channel <br />bedload-transport rate (Ib), is given by: <br /> <br />Ib =(2.52Dto u1- s* - 0.86Dm)1- W, <br /> <br />7 <br /> <br />. <br />