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<br />~, <br /> <br />"~,~, <br /> <br />... . 7' ... <br /> <br />. <br />.. <br /> <br /> <br />TOPPING ET AL. 95 <br /> <br />Figure 8. (A) Three common depositional facies in the Little- <br />Colorado-River-driven unsleady 1993 "000. Vertical sequence <br />showing basal conglomerate (sand clasls. some wilh vertical <br />bedding), beach swash (flat beds), and climbing ripples, Daily <br />flow fluctuations from the dam caused dally transgressions and <br />regressions of these faci~s. (8) Pholograph showing the processes <br />that produce the 3 facies in (A). <br /> <br />subaqueous channel bed, to sandy eddy and channel-margin <br />bars, and then to silty and muddy marsh or floodplain-like <br />deposits that occur along channel margins or atop some <br />eddy bars [Rabin et ai"~ 1990J, <br /> <br />7, CONCLUSIONS <br /> <br />During the 1996 Grand Canyon controlled flood, we <br />documented the coupled evolution of the concentration of <br />suspended sediment, the grain-size distribution of <br />suspended sediment, the grain-size distribution of the <br />sediment on the channel bed, and the grain-size distribution <br />of the flood deposits on eddy bars, At all sites where <br />suspended-sediment measurements were made in Marble <br />and Grand Canyons during the 7 high-discharge days of the <br />1996 controlled flood (i,e" the above LCR gage, the Grand <br />Canyon gage, the 122-Mile eddy site, and the National <br />Canyon gage). the concentrations of sediment in suspension <br />decreased as the suspended sediment coarsened. Thus. <br />decreasing suspended-sediment concentrations associated <br />with coarsening of the suspended sediment were observed <br />at sites along 170 km of the river. Al the Grand Canyon <br /> <br /> <br />a <br /> <br />b <br />