WSP12639

• File Number: 8220.101.10.A
• Description: Colorado River - Water Projects - Glen Canyon Dam-Lake Powell - Glen Canyon AMWG
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/2004
• Author: Schmidt - Topping - Grams - Hazel
• Title: System-Wide Changes in the Distribution of Fine Sediment in the Colorado River Corridor Between Glen Canyon Dam and Bright Angel Creek - Arizona - Final Report - 10-01-04
• Water Supply Pro - Doc Type: Report/Study

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Tables

Table 1. Segment characteristics of the Colorado River in Marble and upper Grand Canyons. . . . . . . 8

Table 2. Depth to bedrock in the valley of the Colorado River. . . . . . . . . . . . . . . . . . . . . . 8

Table 3. Characteristics of the 5 reaches in Marble and upper Grand Canyons where fine-grain alluvium
was mapped and analyzed in a GIS. The sixth reach was Glen Canyon.. . . . . . . . . . . . . 15

Table 4. Estimates of the potential fine-sediment storage volume in 9 EDZs.. . . . . . . . . . . . . . . 17

Table 5. Estimates of the average change in fine sediment thickness in Marble and upper Grand Canyons
under various scenarios of seasonal sediment accumulation, relative proportion of accumulation
stored in eddies and the main channel, and proportion of the main channel where storage occurs. . 28

Table 6. Locations of cross-sections in Glen Canyon indicating which cross-sections were surveyed each
year and the dates of those measurements if known.. . . . . . . . . . . . . . . . . . . . . . .. 29

Table 7. Summary of channel cross-section data at Marble Canyon Dam sites.. . . . . . . . . . . . . . 33

Table 8. Comparison of the area of sand depicted in photographs taken during the Second Powell Expedi-
tion and matched by Stephens and Shoemaker (1987).. . . . . . . . . . . . . . . . . . . 62

Table 9. Summary of changes in sand bars depicted in historical photo matches taken by Turner and
Karpiscak (1980).. . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 10. Aerial photographs analyzed in this study.. . . . . . . . . . . . . . . . . . . . . . . . 69

Table 11. Description of units in pre- and post-controlled flood geomorphic maps. . . . . . . 71

Table 12. Areas above 708 m3/s stage and between 227 and 708 m3/s stages, as surveyed by NAU and
estimated from aerial photographs.. . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Table 13. Error matrix of the agreement between areas surveyed by NAU and estimated by USU.. . . 73

Table 14. Reach-average change in eddy sand bars between pre-dam photographs and the 1990s.. . .. 78

Table 15. Eddy deposition zones (EDZs) that increased or decreased in area between average pre-dam
conditions and the 1990s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Table 16. Summary of temporal trends in area and volume of sand in two elevation zones at sites mea-
sured by NAU.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 17. Mean and median area of post-dam flood sands above the elevation of the stage of 708 m3/s at
study sites in Marble Canyon.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 18. Mean and median area of sand in the fluctuating flow zone, below the elevation of the stage of
708 m3/s and above the stage of 227 m3/s, at study sites in Marble Canyon.. . . . . . . . . . . 90

Table 19. Estimates of loss of fine sediment from eddies between the pre-dam era and the 1990s. . . . . ., 91

Contents VII