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efficiency, which is equivalent to the ratio of mean velocity of water dis- charge through the sampler to the mean velocity of water discharge which would have occurred through the area occupied by the sampler. Emmett (1980) recommended that the Helley-Smith sampler not be used for measuring bedload-transport rates for sediment of particle sizes that also are transported as suspended sediment. Although a large amount of sand size material (0.062 to 2.0 mm) was transported in suspension at Deerlodge Park (see table,8 in the Supplemental Data section at the end of this report), most of this sand was smaller than 0.25 mm and normally passed through the Helley-Smith sample collection bag. A negligible quantity of material less than 0.25 mm in diameter was collected in the Helley-Smith sampler (see table 10 in the Supplemental Data section). Therefore, redundant sampling of material finer than 0.25 mm moving in suspension and as bedload seems to have been avoided at Deerlodge Park. The Modified Einstein procedure may overestimate some sediment discharges at Deerlodge Park because it is based on the condition of a mobile, continu- ous, bank-to-bank sand bed. During many measurements made in 1982 and 1983, the Yampa River at Deerlodge Park had a continuous, bank-to-bank sand bed. However, for most measurements made at discharges greater than about 8,000 ft3/s, the river bed near the left bank was scoured to bedrock for 15 to 30 percent of the channel perimeter (fig. 4). Field crews observed very low bedload discharges in this section of the river when the channel was scoured to bedrock. The Modified Einstein procedure, which extrapolates transported sediment from the zone of suspended movement to the zone of bedload movement, probably overestimates the total-sediment discharge of the Yampa River at Deerlodge Park for most high discharges because the condition of a mobile, continuous sand bed is unfulfilled at intermediate and high water discharges. Sediment transport equations derived using sediment discharges estimated with the Modified Einstein procedure (table 4) may be compared with equations in table 3. In general, regression equation exponents are comparable in tables 3 and 4 for most sediment size categories. However, exponents of the equations for discharge of sediment in the 0.25 to 1.0 mm, and coarser than 1.0-mm size ranges are greater in table 4 than in table 3. This implies that Modified Einstein estimates of coarse sand and gravel discharges increase more with water discharge than do comparable sediment discharges based on observed data. ANNUAL SEDIMENT LOADS The Yampa River channel is adjusted to long-term streamflow and sediment- load regimes. The prevailing hydrologic and sedimentologic conditions must be determined before the potential effects of water resource development in the watershed can be assessed. The average frequency distribution of discharges has been computed from the records of two long-term streamflow-gaging sta- tions. Annual sediment loads were computed by the streamflow-duraticn, sediment-transport-equation method described by Miller (1951). This method is applicable when the gaging-station record of streamflows is sufficient to 18