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<br />. <br /> <br />. <br /> <br />. <br /> <br />001573 <br /> <br />Contents <br /> <br />Abstract <br />1.0 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 1 <br />1.1 The Importance of a Comprehensive History of Geomorphic Change. . . . . ., 3 <br />2.0 Water and Fine-Sediment Fluxes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 <br />3.0 The Valley of the Colorado River. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 7 <br />3.1 Longitudinal Profile and Bed-Material Distribution. . . . . . . . . . . . . . ., 10 <br />3.2 The Fan-Eddy Complex. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 13 <br />3.2.1 Longitudinal Distribution of Eddy Deposition Zones. ........ 15 <br />3.3 Sedimentology of Fine-Grain Alluvial Deposits. . . . . . . . . . . . . . . . ., 18 <br />4.0 Previous Studies in Fine-Sediment Flux and Storage. . . . . . . . . . . . . . . . . . . ., 20 <br />4.1 Previous Projections of Long-Term Changes in the Fine-Sediment Budget. . ., . 21 <br />5.0 Changes in the Topography of the Main-Channel Bed. . . . . . . . . . . . . . . . . . . . 23 <br />5.1 Pre-dam Changes in the Main-Channel Bed, as Measured at the Lees Ferry and <br />Grand Canyon Gages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 <br />5.2 Post-Dam Changes of the Bed in Glen Canyon. . . . . . . . . . . . . . . . . . 25 <br />5.2.1 Rate and Magnitude of Degradation . . . . . . . . . . . . . . . . . . . 31 <br />5.3 Post-dam Changes in the Bed in Marble and Upper Grand Canyons. . . . . . . 32 <br />5.3.1 Bed Changes in Marble and Grand Canyons That Are Probably Post-dam. 33 <br />5.3.2 Changes at the Grand Canyon Gage between 1963 and 2000 and at the <br />Lower Marble Canyon Gage between 1983 and 2000. . . . . . . . . .. 34 <br />5.3.3 Changes in Main Channel Pools Offshore from Eddies between 1992 and <br /> <br />2000. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 <br /> <br />6.0 The History of Fine Sediment Storage at Specific Sites. . . . . . . . . . . . . . . 37 <br />6.1 Badger Creek Rapids. . . . . . . . . . . . . . . . . . . . . . . . . . . 42 <br />6.2 Eminence Break Camp. . . . . . . . . . . . . . . . . . . . . . . . . . 49 <br />7.0 Long-Term Changes in Fine Sediment Storage Shown by Comparison of Oblique <br />Photographs. . . . . . . . . . . . . . . . . . . . . . . . . 61 <br />7.1 Previous Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 <br />7.2 Methods and Results. . . . . . . . . . . . . . . . . . . . . . . . . . . 61 <br />7.2.1 Description of change depicted in some of the photographs . . . . . . .. 63 <br />8.0 Changes in the Area of Fine-Grained Alluvial Deposits Determine by Aerial Photography <br />Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 <br />8.1 Methods............. . . . . . . . . . . . . . . . . . . . . . . . . . 67 <br />8.1.1 Accuracy of mapping. . . . . . . . . . . . . . . . . . . . . . . . . . 72 <br />8.1.2 Metrics used to describe changes in fine-grain deposits among years. ., 74 <br />8.2 Description of the Photograph Series That Were Analyzed. . . . . . . . . . . . .. 75 <br />8.2.1 Pre-dam conditions ofthemid-1930s, 1952, 1954, 1956, 1958. . . . . .. 75 <br />8.2.2 Pulsed high releases of May 1965. . . . . . . . . . . . . . . . . . . . . ., 75 <br />8.2.3 Fluctuating flows ofJune 1973. . . . . . . . . . . . . . . . . . . . . . ., 75 <br />8.2.4 Bypass and spillway floods of the mid-1980s: Octoberl984. . . . . . ., 76 <br />8.2.5 Resumption of wide-ranging hydroelectricity-generating flows: June <br /> <br />1990. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 76 <br /> <br />8.2.6 Interim operating criteria: October 1992, May 1993, and March 1996. ., 76 <br />8.2.7 Effects of the 1996 Controlled Flood: April 1996. . . . . . . . . . . ., 76 <br />8.2.8 Changes in bars after the 1996 Controlled Flood: September 1996 and <br />September 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 76 <br />8.3 Changes in the Area of Fine-Grained Alluvial Deposits Determined by Aerial <br />Photograph Analysis' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 <br />8.3.1 Changes in eddy bars. . . . . . . . . . . . . . . . . . . . . . . . . 77 <br /> <br />Contents III <br />