Laserfiche WebLink
<br />table 13 in the Supplemental Data section at the end of this report). The sum <br />of the annual sand-gravel- and silt-clay-size loads, which should equal the <br />annual total sediment load, was 1.80 million tons--12.percent less than the <br />computed annual total sediment load. This discrepancy probably exists because <br />of the relatively poor definition of sand-gravel- and silt-clay-size material <br />discharges by the linear-regression equations in table 3. Sediment loads were <br />not computed for any other particle-size categories presented in table 3 <br />because of low R2 values and high standard errors of estimates associated with <br />those transport equations. <br /> <br /> <br />Table 5.--Annual sediment loads, station 09260050 Yampa River <br />at Deerlodge Park <br /> <br />Type of sediment <br />load <br /> <br />Measured <br />(tons per year) <br /> <br />Estimated with <br />Modified Einstein <br />(tons per year) <br /> <br />Total------------------------------ <br />Suspended-------------------------- <br />Bedload---------------------------- <br />Sand and gravel-------------------- <br />Silt and clay---------------------- <br /> <br />2,040,000 <br />1,940,000 <br />100,000 <br />790,000 <br />1,010,000 <br /> <br />2,420,000 <br />1,880,000 <br /> <br />1,040,000 <br />1,050,000 <br /> <br />Annual sediment loads for the Vampa River at Deerlodge Park also were <br />computed wi th sediment transport equati ons deri ved from sediment di scharges <br />estimated by the Modified Einstein procedure (table 4). Annual sediment loads <br />computed from estimated sediment discharge data were compared to annual <br />sediment loads computed from measured sediment discharge data (table 5). <br />Annual total sediment load computed with the sediment transport equation <br />derived from estimated sediment discharges was 2.42 million ton/yr, a value <br />16 percent greater than that computed with the sediment transport equation <br />derived from measured sediment discharges. The Modified Einstein procedure <br />does not provide a bedload estimate; therefore, no annual bedload discharge <br />was computed. <br /> <br />Closer inspection of the annual sediment loads in table 5 reveals that <br />the annual silt-clay-size load computed with the sediment transport equation <br />derived from estimated sediment discharges was only 4 percent greater than the <br />annual silt-clay-size load computed with the equation based on measured <br />sediment discharges. By contrast, the annual sand-gravel load computed with <br />the equati on based on estimated sediment di scharges was 32 percent greater <br />than the annual sand-gravel load computed with the equation based on measured <br />sediment discharges. The discrepancy in computed sand-gravel loads Is proba- <br />bly due to undersampling of bedload by the Heiley-Smith sampler, overestima- <br />tion of sand and gravel discharges by the Modified Einstein procedure, or <br />,:umulative error that resulted from using sediment transport equations that <br /> <br /> <br />20 <br />