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Physical Modeling Experiments to Guide River Restoration Projects

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Physical Modeling Experiments to Guide River Restoration Projects FINAL REPORT Physical Modeling Experiments to Guide River Restoration Projects: Restoration Manuals Prepared for CALFED Ecosystem Restoration Program (Contract No. ERP-02D-P55) Prepared by Stillwater Sciences Berkeley, California Department of Earth and Planetary Science University of California, Berkeley, California and Department of Geosciences San Francisco State University, San Francisco, California March 2008 Suggested citation: Stillwater Sciences, UC Berkeley, and SFSU. 2008. Physical Modeling Experiments to Guide River Restoration Projects: Final Report (Restoration Manuals). Contract No. ERP-02D-P55. Prepared for CALFED Ecosystem Restoration Program, Sacramento. FINAL REPORT Physical Modeling Experiments to Guide River Restoration Projects Restoration Manuals Table of Contents 1 INTRODUCTION ......................................................................................................................... 1 2 GRAVEL AUGMENTATION: LESSONS FROM THE LABORATORY............................. 3 2.1 Introduction............................................................................................................ 3 2.2 Options for Reversing the Effects of Dams on Bed Mobility and Texture............ 6 2.3 Experiments ........................................................................................................... 7 2.3.1 Prototype................................................................................................... 7 2.3.2 1D Experiments......................................................................................... 8 2.3.3 2D Fixed Bar Experiments ....................................................................... 9 2.3.4 Free-bar experiments.............................................................................. 10 2.4 Summary and Discussion..................................................................................... 11 2.4.1 What happens to the injected sediment?................................................. 11 2.4.2 How do sediment pulses interact with resident bed material? ............... 12 2.4.3 Can gravel augmentations be used to fine gravel bed surfaces?............ 13 2.4.4 Can gravel augmentations be used to flush fine sediment from bed material?................................................................................................. 14 2.4.5 Can augmentations rebuild channel topography?.................................. 14 2.5 Optimizing Pulse Size and Frequency for Stream Restoration............................ 15 2.6 Scaling-Up from the Laboratory to the Field....................................................... 17 2.6.1 Scaling-up the 1D laboratory experiments to the field........................... 17 2.6.2 Using 2D experiments as process analogues for the field...................... 18 2.6.3 Spatial scaling considerations................................................................ 18 2.6.4 Temporal scaling considerations............................................................ 19 2.7 Conclusions.......................................................................................................... 20 2.8 Acknowledgements.............................................................................................. 21 2.9 References............................................................................................................ 21 2.10 Figures ................................................................................................................. 25 3 MANAGING THE RELEASE OF SEDIMENT RESULTING FROM DAM REMOVAL: AN APPROACH INFORMED BY PHYSICAL AND NUMERICAL MODELING............ 39 3.1 Introduction.......................................................................................................... 39 3.2 Sediment Management Issues Related to Dam Removal .................................... 42 3.3 An Approach to Dam Removal Sediment Management...................................... 44 3.4 Understanding Characteristics of the Reservoir Deposit and Downstream Reach45 3.4.1 Grain-size distribution, volume and quality ........................................... 45 3.4.2 Channel morphology downstream of the dam ........................................ 46 3.4.3 Reach sediment budget ........................................................................... 46 3.5 Estimating Flood Risk ......................................................................................... 47 3.6 Evaluating Constraints 1: Reach-Scale Transport and Deposition Characteristics of Sediment Pulses............................................................................................... 47 3.6.1 Numerical modeling................................................................................ 47 3.6.2 Suspended sediment and turbidity .......................................................... 49 7 March 2008 i FINAL REPORT Physical Modeling Experiments to Guide River Restoration Projects Restoration Manuals 3.7 Evaluating Constraints 2: Sediment Pulse Movement Through a Pool-Bar Morphology ......................................................................................................... 50 3.7.1 Physical modeling................................................................................... 50 3.7.2 Representing complex pulse movement using numerical models ........... 51 3.8 Predicting Impacts 3: Fine Sediment Infiltration into Coarse Bed Sediment ...... 51 3.8.1 Theoretical analysis................................................................................ 52 3.8.2 Flume experiments.................................................................................. 52 3.9 Selecting the Dam Removal Alternative.............................................................. 52 3.10 Monitoring and Evaluation .................................................................................. 53 3.11 Lessons for Dam Removal Projects..................................................................... 54 3.12 Conclusions.......................................................................................................... 56 3.13 Acknowledgements.............................................................................................. 57 3.14 References............................................................................................................ 57 3.15 Figures ................................................................................................................. 64 4 CONDITIONS NECESSARY TO CREATE MEANDERING CHANNELS: INFERENCES FROM FLUME EXPERIMENTS.............................................................................................. 73 4.1 Introduction.......................................................................................................... 73 4.2 Meandering River Data Set.................................................................................. 75 4.3 Background.......................................................................................................... 75 4.4 Flume Experiments.............................................................................................. 77 4.4.1 Scaling the flume experiments ................................................................ 78 4.4.2 Experimental measurements................................................................... 79 4.5 Results.................................................................................................................. 79 4.6 Discussion............................................................................................................ 81 4.7 Applications to Stream Restoration ..................................................................... 82 4.8 Conclusions.......................................................................................................... 83 4.9 Acknowledgements.............................................................................................. 83 4.10 References............................................................................................................ 84 4.11 Figures ................................................................................................................. 88 Figures Figure 2-1. Shifting surface grain-sizes using gravel augmentation...........................................................................25 Figure 2-2. Schematic diagram of the RFS flume and its associated facilities (From Cui et al., in review A)...........26 Figure 2-3. Sediment size distribution of the bed material, bed surface, and the sediment pulses during the 1D RFS, 2D RFS, and 2D SAFL experiments. Surface from the SAFL experiment is an area by weight.......................27 Figure 2-4. Facies map of the bed of the RFS experiments at the end of the 40 kg/hr run feed (top) and the end of the no feed experiment (bottom). Terms in the legend refer to the transport condition of the bed. Congested refers to a coarse patch and smooth refers to a patch of fine gravel. See Nelson et al. (in prep.) for further details..................................................................................................................................................................28 Figure 2-5. RFS 2D Fixed bar configuration during equilibrium conditions with a constant 0.02 m3/s water discharge and 40 kg/hr sediment feed (From Cui et al., in review B).................................................................28 Figure 2-6. Topographic adjustment of the bed following elimination of the upstream sediment
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