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<br />002452 <br /> <br /> <br />CONTENTS <br /> <br /> <br />CONTENTS......................................... .............. ...... ................ ...................................... ..... 2 <br /> <br />ABSTRACT....,....................................,...... ................ ....... ...... ...................................... ..... 4 <br /> <br />INTRODUCTION ...,.......,..................., ,..... ..... ....................... ........... ........,....... ................. 6 <br /> <br />STUDY AREA.... ...........,................,., ..... ....... ............. ........................... .....,..... ................. 7 <br /> <br />Physiographic Setting......................,................ ..... .................. ........ ................ .......... ..... 7 <br /> <br />Streamflow Regulation.............,...... ........,.....,....... ........................... .............................. 9 <br /> <br />Sediment Supply............................................. ................. ................................. .............. 9 <br /> <br />Previous Geomorphic Investigations in Glen Canyon.................................................. 11 <br /> <br />METHODS........ ................,....... ....... .............. ....... ........... .....,. .................. ........,......... ..... 14 <br /> <br />Measurements of the Bed.............. ............. ............... ................................................. ,.. 14 <br />Bureau of Reclamation Cross-sections ..................................................................... 14 <br />Lees Ferry Gaging Station .,..................,................................................................... 15 <br />Mapping of Alluvial Deposits............ ........................,........................................ .......... 17 <br />Mapping From Aerial Photographs .......................................................................... 17 <br />Characterization of Eddy Deposits ............,...... .......... ....... .............. ............. ............ 20 <br />Accuracy of the Surficial Geologic Maps................................................................. 21 <br /> <br />RESULTS. ............................. .................. ......... ..... ...... ......... ......,.. ............. ............... ....... 23 <br /> <br />Rate and Magnitude of Bed Degradation... ...... ................... ..... ............ ........... ...... ........ 23 <br />The onset of degradation and the channel cleaning flows ......................................., 23 <br />Continued degradation and the magnitude of sediment evacuation ......................... 24 <br />Spatial pattern of bed adjustment and development ofthe post-dam longitudinal <br /> <br />profile.......... ................................. ..... ........ .......,. ............................ ............... ............ 25 <br /> <br />Magnitude of bed degradation relative to pre-dam scour-and-fill............................ 27 <br />Upper Lees Ferry Cableway ................................................................................. 27 <br />Lower Lees Ferry Cableway...... ........ ....... ..... ..... ......... ,.. ..... ................................. 28 <br />Channel-width changes at the Lower Lees Ferry Gableway ........................................ 29 <br />Alluvial Deposits in Glen Canyon ................................................................................ 31 <br />Glen Canyon in 1952 ................................................................................................ 31 <br />Glen Canyon in 1984-2000 ....................................................................................... 32 <br />Erosion and Deposition of Alluvial Deposits ............................................................... 33 <br />Erosion and Deposition: 1950s to 1984.................................................................... 33 <br />Erosion and Deposition: 1984 to 1996...................................................................... 35 <br />Erosion and Deposition in Eddies ............................................................................. 36 <br /> <br />DISCUSSION ..........,.................... ............ ......... ................. ................. ............................. 37 <br /> <br />Adjustment of the Bed............ ............... ....... .................................. .............................. 37 <br />Adjustment of Alluvial Deposits.. ........ ....... ................. .......... ........ ............. ........... ...... 40 <br /> <br />CONCLUSIONS......................,............... ......... ........ ............................. ............... ............ 41 <br /> <br />REFERENCES ............................................ ....... ,.. .................................. ........,...... .......... 43 <br /> <br />TABLES................... ..........................,............... ....... ................................ ............... ........ 46 <br /> <br />FIGURE CAPTIONS.......... ................,........... ...................,........ ................,. .................... 53 <br /> <br />FIGURES .................................. ...............".. .... .......... ..... ........... ........, .............................. 56 <br /> <br />APPENDICES ............................. ............. ...... ...... .....................,........................ .....,........ 83 <br /> <br />Appendix A: Pre-dam Sediment Transport and Storage in Glen Canyon ................... 83 <br /> <br />2 <br />