8267

• UCREFRP Catalog Number: 8267
• Author: Elliott, J. G. and L. A. Hammack.
• Title: Geomorphic and Sedimentologic Characteristics of Alluvial Reaches in the Black Canyon of the Gunnison National Monument, Colorado.
• USFW Year: 1999.
• USFW - Doc Type: Water-Resources Investigations Report 99-4082,
• Copyright Material: NO

CONTENTS
Abstract .................................................................................................................................................................................. 1
Introduction ............................................................................................................................................................................ 1
Purpose and Scope ....................................................................................................................................................... 2
Acknowledgments ....................................................................................................................................................... 2
Study Area ............................................................................................................................................................................. 2
Geologic Setting .......................................................................................................................................................... 2
Riparian Zone Characteristics ...................................................................................................................................... 2
Hydrology .................................................................................................................................................................... 4
Geomorphic and Sedimentologic Characteristics .................................................................................................................. 9
Aerial Photography ...................................:.................................................................................................................. 9
Monumented Oblique Photography ............................................................................................................................. 9
Geomorphic Surveys .................................................................................................................................................... 10
Sediment-Size Analysis ............................................................................................................................................... 13
One-Dimensional Streamflow Modeling ..................................................................................................................... 13
Shear Stress Distribution ............................................................................................................................................. 13
Sediment Entrainment ................................................................................................................................................. 24
Summary ................................................................................................................................................................................ 45
References Cited .................................................................................................................................................................... 46
Appendix ................................................................................................................................................................................ 49
FIGURES
1. Map of the Gunnison River and the Black Canyon of the Gunnison National Monument, Colorado ...................... 3
2. Photograph showing fluvially deposited bars in the upper part of the Warner Point study reach ............................. 5
3. Profile of the Gunnison River and graph showing the location and relative abundance of alluvial
deposits in Black Canyon of the Gunnison National Monument .............................................................................. 6
4-5. Maps of:
4. Warner Point study reach showing location of surveyed cross sections and oblique-photography monuments ...... 7
5. Red Rock Canyon study reach showing location of surveyed cross sections and oblique-photography
monuments ................................................................................................................................................................ 8
6-9. Plots showing:
6. Channel cross section, shear stress distribution, and critical shear stress for sediment median particle size
in the Warner Point study reach ................................................................................................................................ 25
7. Channel cross section, shear stress distribution, and critical shear stress for sediment median
particle size in the Red Rock Canyon study reach .................................................................................................... 33
8. Sediment-entrainment potential on similaz geomorphic surfaces in the Warner Point
study reach ................................................................................................................................................................ 40
9. Sediment-entrainment potential on distal debris-fan surfaces in the Red Rock Canyon
study reach ................................................................................................................................................................ 44
10-18. Replicate photographs showing:
10. Warner Point study reach from monument 0011-A, downstream view of Bar 8.2L neaz cross section VS ............. 50
11. Warner Point study reach from monument 0020-B, downstream view of Baz 8.5 near cross section H34 .............. 52
12. Warner Point study reach from monument 0021-A, upstream view of Baz 8.SR near cross section H3 .................. 54
13. Warner Point study reach from monument 0021-D, downstream view of Bar 8.SR near cross section H60 ........... 56
14. Red Rock Canyon study reach from monument 0003-B2, cross-channel view of bar near cross section Gl .......... 58
15. Red Rock Canyon study reach from monument 0005-D, downstream view of debris fan at Tributary 11.3R ........ 60
16. Red Rock Canyon study reach from monument 0006-B, downstream view of baz above cross section H2............ 62
17. Red Rock Canyon study reach from monument 0010-U, upstream view of debris-fan distal margin
near cross section H116 ............................................................................................................................................ 64
18. Red Rock Canyon study reach from monument 0011-U, upstream view debris-fan distal margin
near cross section F118 ............................................................................................................................................. 66
CONTENTS III