Sediment Transport During Three Controlled-Flood Experiments on the Colorado River Downstream from Glen Canyon Dam, with Implications for Eddy- Sandbar Deposition in Grand Canyon National Park Open-File Report 2010–1128 U.S. Department of the Interior U.S. Geological Survey Cover: Nick Voichick (left), Greg Shellenbarger (center), and Steve Jones (right) in the sampling boat at the river-mile 61 study site on March 7, 2008, during high, steady discharge during the 2008 controlled-flood experiment (USGS photo by David J. Topping). Sediment Transport During Three Controlled-Flood Experiments on the Colorado River Downstream from Glen Canyon Dam, with Implications for Eddy- Sandbar Deposition in Grand Canyon National Park By David J. Topping, David M. Rubin, Paul E. Grams, Ronald E. Griffiths, Thomas A. Sabol, Nicholas Voichick, Robert B. Tusso, Karen M. Vanaman, and Richard R. McDonald Open-File Report 2010–1128 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia 2010 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Suggested citation: Topping, D.J., Rubin, D.M., Grams, P.E., Griffiths, R.E., Sabol, T.A., Voichick, N., Tusso, R.B., Vanaman, K.M., and McDonald, R.R., 2010, Sediment transport during three controlled-flood experiments on the Colorado River downstream from Glen Canyon Dam, with implications for eddy-sandbar deposition in Grand Canyon National Park: U.S. Geological Survey Open-File Report 2010-1128, 111 p. 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Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. ii Contents Notation..............................................................................................................................................................................vii Abstract................................................................................................................................................................................1 Introduction .........................................................................................................................................................................1 Purpose and Scope........................................................................................................................................................5 Theoretical Background................................................................................................................................................5 Acknowledgments........................................................................................................................................................11 Study Sites.........................................................................................................................................................................11 Data.....................................................................................................................................................................................13 Removal of Bias in Data Collected by D-77-Bag-Type Samplers ........................................................................26 Errors ..............................................................................................................................................................................27 Antecedent Conditions for Each Controlled-Flood Experiment (CFE).....................................................................28 Brief Description of Sand-Budgeting Approach.....................................................................................................28 Sand Enrichment in Each Reach Before the 2004 and 2008 CFEs .......................................................................32 Estimation of the Relative Levels of Sand Enrichment Antecedent to the 1996, 2004, and 2008 CFEs..........34 Analysis..............................................................................................................................................................................35 Data Collected at Each Study Site During Each CFE..............................................................................................35 Data Collected at Each Study Site During All CFEs................................................................................................53 Data Collected During Each CFE at All Study Sites................................................................................................65 Sediment Export Past the Study Sites During the 1996, 2004, and 2008 CFEs....................................................70 Sand Budgeting During the 2004 and 2008 CFEs.....................................................................................................70 Lagrangian Sampling-Program data.........................................................................................................................71 β Analysis...........................................................................................................................................................................79 Values of β at Each Study Site During All CFEs ......................................................................................................84 Estimation of Differences in Reach-Averaged Bed-Sand Area in the Reaches Upstream from Each Study Site During Each CFE and Between CFEs.....................................................................................................86 Values of β at All Study Sites During Each CFE ......................................................................................................89 β Analysis of Data Collected During the Lagrangian Sampling Programs, with Estimation of Relative Differences in Reach-Averaged Bed-Sand Area Between the 2004 and 2008 CFEs........................92 Size, Known Levels of Sand Enrichment, and Mean Suspended-Sand Concentration in Each Reach During the 1996, 2004, and 2008 CFEs ...........................................................................................................97 Conclusions .....................................................................................................................................................................101 References Cited ............................................................................................................................................................103 iii Figures 1. Comparison of the flood hydrographs of the 1996, 2004, and 2008 CFEs at the USGS Colorado River at Lees Ferry, Arizona gaging station................................................................................................................3 2. Pre-dam annual and partial-duration flood-frequency analysis for the Colorado River at Lees Ferry, Arizona gaging station..............................................................................................................................4 3. Map showing locations of study sites and reaches between the study sites..................................................12 4. Hydrographs, suspended-sediment data, and bed-sand data collected at each study site during each CFE...............................................................................................................................................................37 5. Hydrographs, suspended-sediment data, and bed-sand data collected at each study site during all three CFEs.......................................................................................................................................................54 6. Bed-silt and clay data collected at each study site during all three CFEs. .......................................................61 7. Suspended-sand data collected during each CFE at all study sites...................................................................66 8. Suspended-sediment data collected in the Lagrangian sampling programs during the 2004 and 2008 CFEs..............................................................................................................................................................72 9. Comparison of suspended-sand concentration and grain-size data collected in the Lagrangian sampling programs during the 2004 and 2008 CFEs......................................................................................78 10. Influence of changes in reach-averaged bed-sand area on β..........................................................................82 11. Values of β at each study site during all CFEs ......................................................................................................84 12. β-based computation of reach-averaged bed-sand area in the reaches upstream from each study site during each CFE................................................................................................................................88 13. Results from β and βA analyses of reach-averaged bed-sand median grain size