Reservoir sedimentation handbook: design and management of dams, reservoirs, and watersheds for sustainable use

COVER PAGES......Page 1
Preface 1.04......Page 0
1.1 Need For Sediment Management......Page 11
1.2 ELEMENTS OF SEDIMENT MANAGEMENT......Page 14
1.3 HANDBOOK APPROACH......Page 15
2.1.1 Global Water Resources......Page 16
2.1.2 Water Scarcity......Page 17
2.2 IMPORTANCE OF RESERVOIRS......Page 20
2.3.1 Upstream Consequences......Page 23
2.3.2 Downstream Consequences......Page 25
2.4 CONCEPTS OF RESERVOIR LIFE......Page 28
2.5 GEOMORPHIC STAGES OF RESERVOIR LIFE......Page 29
2.6 RATE OF STORAGE LOSS......Page 31
2.7 CONCEPTS OF SUSTAINABLE DEVELOPMENT......Page 32
2.8 RESERVOIRS AS NONRENEWABLE RESOURCES......Page 35
2.9 ECONOMICS AND SUSTAINABILITY......Page 37
2.10 CRITERIA-BASED APPROACH TO SUSTAINABILITY......Page 38
2.11.1 Sedimentation Assessment......Page 39
2.11.4 Screening of Sediment Management Alternatives......Page 40
2.11.6 Design, Implementation, and Monitoring of ControlMeasures......Page 41
2.12 POPULATION AND FOOD SUSTAINABILITY......Page 42
3.1.1 Dams in Antiquity......Page 44
3.1.2. Modern Dam Construction......Page 46
3.2.2 Embankment Dams......Page 47
3.2.3 Concrete Dams......Page 48
3.3.1 Reservoir Size......Page 49
3.3.2 Pool Geometry......Page 50
3.3.4 Stage-Storage Relationships......Page 51
3.3.5 Types of Reservoir Operation......Page 52
3.4 OUTLETS AND GATES......Page 54
3.5.2 Types of Hydraulic Turbines......Page 55
3.5.4 Sediment Impact on Tailwater......Page 57
3.6.2 Abrasion of Concrete Structures......Page 59
3.6.3 Cavitation......Page 60
3.8 RESERVOIR YIELD......Page 62
3.8.2 Gould's Gamma Method for Estimating Yield......Page 63
3.8.4 Hydrologic Time Series......Page 65
3.8.5 Sedimentation Effect on Yield......Page 66
4.1.2 Hydrologic Size and Loading Rate......Page 68
4.1.4 Geometry and Longitudinal Gradients......Page 70
4.2.1 Stratification......Page 71
4.2.2 Seasonality of Stratification......Page 72
4.2.3 Density of Water......Page 73
4.3.1 Horizontal Focusing......Page 74
4.3.2 Vertical Focusing......Page 75
4.4 SELECTIVE WITHDRAWAL......Page 76
4.5 LIGHT AND TRANSPARENCY......Page 78
4.6.2 Diurnal Variations in Dissolved Oxygen......Page 79
4.6.3 Productivity......Page 80
4.6.5 Trophic Status......Page 81
4.7.1 The Concept of Limiting Nutrients......Page 83
4.7.2 Phosphorus......Page 84
4.7.3 Nitrogen......Page 86
4.8 GRADIENTS, SEDIMENTATION, AND                   BIOLOGICAL PROCESSES......Page 87
4.9 CLOSURE......Page 89
5.1.1. Size of Sediment Grains......Page 90
5.1.2. Particle Shape and Roundness......Page 91
5.1.3. Grain Size Distribution......Page 93
5.1.4. Classification by Mode of Transport......Page 94
5.2.3 Clay and Clay Flocculation......Page 96
5.3.1  Sediment Density and Weight......Page 98
5.3.3 Angle of Repose......Page 100
5.4.1 Void Space......Page 101
5.4.2 Sediment Concentration......Page 102
5.5.1 Fluid Viscosity......Page 103
5.5.2 Reynolds Number......Page 104
5.5.5 Simplified Equations for Fall Velocity......Page 105
5.5.7 Sweep Flocculation and Hindered Settling......Page 107
5.6.1 Filtration Method......Page 110
5.6.4 Sediment Volume......Page 111
5.7 LABORATORY ANALYSIS OF SEDIMENT SIZE......Page 112
5.7.1 Use of Deflocculants......Page 113
5.7.4 Dry Sieving......Page 114
5.7.6 Direct Measurement of Nominal Diameter......Page 115
5.7.10 Hydrometer......Page 116
6.1 CONCEPTS AND DEFINITIONS......Page 118
6.2.2 Off-Site Impacts......Page 123
6.3 EROSION RATE......Page 124
6.4.1 Interrill Erosion......Page 125
6.4.2 Rainfall......Page 126
6.4.3 Rill Erosion......Page 127
6.4.4 Size of Eroded Particles......Page 128
6.5.1 Gully Erosion Process......Page 129
6.5.2 Quantification of Gully Erosion......Page 131
6.6.1 Processes......Page 132
6.6.2 Quantifying Channel Erosion......Page 133
6.7 SLOPE FAILURE......Page 134
6.8 FIELD MEASUREMENT OF EROSION......Page 135
6.8.3 Experimental Watersheds......Page 136
6.8.4 Measurement Equipment......Page 137
6.8.5 Simulated Rainfall......Page 138
6.8.6 Other Methods......Page 139
6.9 EROSION MODELING WITH USLE AND RUSLE......Page 140
6.10 EROSION MODELING USING WEPP......Page 142
6.11.1 Basic Delivery Ratio Concepts......Page 143
6.11.2 Causes of Reduced Sediment Delivery......Page 144
6.11.4 Variation in Delivery Ratio......Page 146
6.11.5 Estimating Sediment Delivery Ratio......Page 148
6.11.6 Sediment Sorting and Enrichment......Page 150
6.12 CLOSURE......Page 153
7.1 SPATIAL VARIABILITY IN SEDIMENT YIELD......Page 154
7.2.2 Within-Storm Variation in Suspended Load......Page 158
7.2.5 Long-Term Changes in Sediment Yield Due to Disturbances......Page 163
7.2.6 Changes in Long-Term Yield Due to Geomorphic Factors......Page 168
7.3.1 Reservoir Resurvey......Page 171
7.3.2 Fluvial Monitoring......Page 173
7.3.3 Uncertainty in Sediment Yield......Page 174
7.3.4 Quantifying Interannual Variability in Sediment Load......Page 175
7.4 SEDIMENT RATING CURVES......Page 176
7.4.1 Fitting Sediment Rating Curves......Page 177
7.4.3 Mathematical Curve Fitting......Page 178
7.4.4 Rating Curve Example......Page 180
7.5.1 Time-Series Sediment Rating Curve Technique......Page 181
7.5.4 Estimating Bed Load......Page 182
7.6.1 Regional Rate of Storage Loss......Page 183
7.6.2 Regional Regression Relationship......Page 184
7.6.3 PSIAC Method......Page 185
7.6.4 Sediment Yield Maps......Page 188
7.6.5 Erosion Modeling......Page 189
7.7 GIS AND EROSION PREDICTION......Page 190
7.8.2 Direct Measurement......Page 192
7.8.4 Sediment Fingerprinting......Page 193
7.9 CLOSURE......Page 196
8.1.1 Stream Order......Page 198
8.1.3 Stream Patterns......Page 199
8.1.4 Meandering and Stream Migration......Page 200
8.1.5 Lane's Balance......Page 202
8.1.6 Differences between Sand and Gravel Bed Streams......Page 203
8.1.7 Armoring......Page 204
8.2 SUSPENDED-SEDIMENT SAMPLING......Page 205
8.2.2 Isokinetic Sampling......Page 206
8.2.3 Sampling Location......Page 207
8.2.5 Depth-Integrating Sampler......Page 208
8.2.6 Point-Integrating Sampler......Page 209
8.2.7 Sampling in Transverse Direction......Page 210
8.3.1 Equipment Description......Page 211
8.3.2 Sampler Intake Placement......Page 212
8.3.3 Sampling Depth......Page 213
8.3.4 Nozzle Orientation......Page 214
8.4.1 Application......Page 215
8.4.3 Relationship between Turbidity and Suspended Solids......Page 216
8.4.4 Limitations of Turbidity Data......Page 218
8.5.1 Statistically Based Strategies for Pumped Samplers......Page 219
8.5.2 Sampling Strategies for Turbidimeters......Page 220
8.7.1 Bed Load Transport......Page 221
8.7.2 Bed Load Sampling......Page 222
8.7.3 Continuous Bed Load Measurement......Page 223
8.8.2 The Sampling Problem in Gravel-Bed Streams......Page 224
8.8.3 Selection of Sampling Areas......Page 225
8.8.4 Selection of Sampled Stones......Page 226
8.8.6 Frequency by Size Class......Page 227
8.8.9 Truncated Samples......Page 228
8.9 BED MATERIAL GRAIN SIZE CONVERSION FACTORS......Page 229
8.9.1 Areal Count to Bulk Sieve Conversion......Page 231
8.10.1 Sampling Precision and Accuracy......Page 232
8.10.2 Sampling Equipment......Page 233
8.10.3 Number of Sampling Points......Page 234
8.10.5 Rating Curves......Page 236
8.11CLOSURE......Page 237
HYDRAULICS OF SEDIMENT TRANSPORT......Page 239
9.1 DEFINITIONS AND UNITS......Page 240
9.2.2 Manning Equation......Page 242
9.3.1 Grain Roughness......Page 243
9.3.2 Estimating Total Roughness......Page 244
9.3.3 Cowan's Method......Page 246
9.3.4 Effect of Vegetation on Flow Resistance......Page 251
9.5.1 Reynolds Number......Page 253
9.5.4 Vertical Velocity Distribution......Page 256
9.6  VERTICAL DISTRIBUTION OF SEDIMENT CONCENTRATION......Page 258
9.7 INITIATION OF MOTION......Page 259
9.7.1 Bed Shear or Tractive Force......Page 260
9.7.4 Shields Diagram......Page 261
9.7.5 Velocity Criteria......Page 264
9.7.6 Annandale's Erodibility Index Method......Page 265
9.7.7 Example 9.1......Page 268
9.7.8 Example 9.2......Page 269
9.8.1 Shear Stress Distribution......Page 270
9.8.2 Slope Stability......Page 271
9.9.1 Ackers and White......Page 272
9.9.3 Yang's Equation for Sand Transport......Page 274
9.9.5 Yang's Modification for Water-Sediment Mixtures......Page 276
9.10 HYPERCONCENTRATED FLOW......Page 277
9.11.1 Importance of Cohesive Sediments......Page 278
9.11.2 Settling and Compaction of Cohesive Sediment......Page 280
9.11.3 Rheology of Cohesive Sediment Mixtures......Page 282
9.11.4 Laboratory Testing of Cohesive Sediment......Page 283
9.11.5 Erosion Thresholds for Cohesive Sediment......Page 285
9.11.7 Deposition Rate of Cohesive Sediment......Page 287
9.11.8 Angle of Repose......Page 288
9.11.9 Settling of Individual Coarse Particles......Page 289
9.12 CLOSURE......Page 290
10.2 GENERALIZED DEPOSITION PATTERNS......Page 292
10.2.2 Longitudinal Deposit Geometry......Page 293
10.2.3 Lateral Deposition Patterns......Page 294
10.2.5 Influence of Regulation Regime......Page 296
10.3.1 Delta Deposition Patterns......Page 297
10.3.2 Slope of Delta Deposits......Page 302
10.4.2 Horizon Tracing Using 137Cesium......Page 304
10.4.4 Spud Surveys......Page 305
10.4.5 Sedimentation Plates......Page 306
10.5.2 Survey Intervals......Page 307
10.5.4 Survey Errors......Page 308
10.6.1 Contour Survey Methods......Page 309
10.7.1 Location of Ranges......Page 311
10.7.4 Average End Area......Page 313
5.1.1. Constant Factor Method......Page 314
EFFICIENCY......Page 315
10.8.1 Brune Curve......Page 317
10.8.2 Churchill Method......Page 318
10.9.1 Compaction Processes......Page 319
10.9.3 Lara-Pemberton Method for Initial Bulk Density......Page 320
10.9.4 Sediment Compaction......Page 322
10.10.2 Area-increment and Empirical Area Reduction Methods......Page 323
10.11 SAMPLING SEDIMENT DEPOSITS......Page 330
10.11.2 Sampling for Chemical Contaminants......Page 331
10.11.4 Gravity Corers......Page 332
10.12 CLOSURE......Page 333
11.2 MODELING PROTOCOL......Page 334
11.3 CONCEPTUAL MODELING......Page 337
11.4 NUMERICAL MODELING......Page 339
11.5.1 Hydrology......Page 340
11.5.3 Selection of Transport Equation......Page 341
11.5.4 Calibration......Page 344
11.6.1 HEC-6......Page 347
11.6.2 GSTARS......Page 349
11.6.3 FLUVIAL......Page 350
11.6.5 SSIIM......Page 351
11.7 PHYSICAL MODELING......Page 352
11.7.1 Applicability of Physical Models......Page 354
11.9 EXAMPLES OF PHYSICAL MODEL SCALING AND OPERATION......Page 355
11.9.1 Problem Identification......Page 357
11.9.2 Model Type and Scales......Page 358
11.9.5 Calibration......Page 359
11.9.8 Validation......Page 360
11.10 CLOSURE......Page 361
12.1.1 Applicability......Page 362
12.1.2 Limitations......Page 363
12.1.3 Additional Sources of Information......Page 364
12.2.1 Technical Strategies for Erosion Control......Page 365
12.2.3 Types of Sediment Trapping Structures......Page 368
12.2.5 Sediment Trapping versus Erosion Control......Page 369
12.3.1 What Causes Erosion?......Page 370
12.3.2 Identifying and Prioritizing Sediment Sources......Page 371
12.3.3 Identification of Partners......Page 372
12.3.4 Economic Costs, Benefits, and Erosion Control Strategies......Page 373
12.4 EROSION CONTROL MEASURES ON FARMS......Page 374
12.4.4 Conservation Tillage......Page 375
12.4.5 Grassed Waterways......Page 376
12.4.7 Contour-Grassed Hedges......Page 377
12.5.2 Criteria for Successful Erosion Control......Page 380
12.6 EROSION CONTROL ON MECHANIZED FARMS......Page 382
12.7 EROSION CONTROL ON SUBSISTENCE FARMS......Page 383
12.7.2 Terracing......Page 384
12.7.4 The World Neighbors Program in Honduras......Page 385
12.7.5 Implementation in Ecuador......Page 386
12.8.1 Definitions......Page 387
12.8.3 Yarding Methods......Page 388
12.8.5 Riparian Buffer Strips......Page 390
12.8.6 Logging Roads......Page 391
12.9 RESERVOIR SHORELINE EROSION......Page 392
12.10.2 Basic Strategy for Gully Control......Page 393
12.10.3 Check Dams......Page 394
12.10.4 Vegetative Control of Gullying......Page 396
12.11 EROSION CONTROL STRATEGIES FOR RANGELAND......Page 397
12.12 EROSION CONTROL STRATEGIES IN URBANIZING AREAS......Page 399
12.13.1 Design Philosophy......Page 400
12.13.2 Detention Basin Geometry......Page 402
12.13.3 Design Computations for Plug Flow......Page 404
12.13.5 Dewatering Orifice......Page 409
12.13.6 Weir Discharge......Page 410
12.14.1 Debris Basin Configurations......Page 411
12.14.2 Sediment Trapping by Debris Basins......Page 412
12.14.3 Debris Basin Cleanout......Page 414
12.15 CLOSURE......Page 415
8B13.1.2 Classification of Techniques......Page 417
9B13.1.3 Advantages and Disadvantages......Page 418
12B13.2.3 Partial Drawdown at Three Gorges Project......Page 419
13B13.2.4 Seasonal Emptying of Reservoir......Page 422
14B13.3.1 Technique......Page 423
15B13.3.2 Sediment Balance by Flood Routing......Page 424
16B13.3.3 Sediment Adjustments under Routing......Page 425
18B13.4.3 Operational Sequence......Page 426
20B13.4.5 Hydrograph Prediction......Page 428
22B13.5.2 Operational Example......Page 429
24B13.6.2 Application......Page 431
25B13.7.1 Technique......Page 432
26B13.7.2 Application......Page 433
27B13.7.3 Computation of Reservoir Yield and Sediment Exclusion......Page 434
4B13.8 SUBSURFACE RESERVOIR......Page 436
5B13.9 SEDIMENT EXCLUSION......Page 437
30B13.9.3 Gravel Sluice......Page 438
31B13.9.4 Intakes at Large Dams......Page 439
34B13.10.2 Reservoirs in Series......Page 440
7B13.11 CLOSURE......Page 441
14.1 INTRODUCTION......Page 442
14.2.1 Variation in Density......Page 444
14.2.3 Plunging Flow......Page 445
14.2.5 Turbidity Current Forward Motion......Page 447
14.2.6 Turbidity Current Behavior at a Bend......Page 448
14.2.7 Submerged Muddy Lake......Page 449
14.3.2 Muddy Lake Deposits......Page 450
14.5.1 Blockage of Low-Level Outlets......Page 454
14.5.2 Turbidity Currents at a Confluence......Page 455
14.6 VERTICAL STRUCTURE OF TURBIDITY  CURRENTS......Page 457
14.7.3 Timing and Duration of Releases......Page 459
14.7.4 Discharge......Page 460
14.7.5 Height of Aspiration......Page 462
14.8.1 Computational Strategy......Page 464
14.8.3 Grain Size That Can Be Transported......Page 465
14.9 MONITORING DENSITY CURRENT MOVEMENT......Page 466
14.10 CLOSURE......Page 467
15.1.2 Classification of Techniques......Page 469
15.1.3 Applications......Page 470
15.1.4 Limitations......Page 471
15.2.2 Accumulation of Coarse Sediment Deposits during Flushing......Page 472
15.2.3 Channel Formation and Maintenance......Page 474
15.2.4 Flushing Procedures......Page 476
15.3.1 Empty Flushing during Flood Season......Page 477
15.4.1 Pressure Flushing......Page 478
15.4.2 Flushing with High-Level Outlet......Page 481
15.5.1 Slumping at the Dam......Page 483
15.5.2 Slope Failure......Page 485
15.5.3 Retrogressive Erosion......Page 486
15.6 VARIATION IN EROSION RATE AND SEDIMENT RELEASE......Page 487
15.6.2 Between-Event Variability......Page 488
15.6.3 Effect of Discharge on Erosion Rate......Page 489
5.1.1. 15.7.1 Definition......Page 490
15.7.2 Flushing Efficiency with Partial Drawdown......Page 491
15.7.3 Flushing Efficiency with Emptying......Page 492
15.8.1 Lateral Erosion......Page 493
15.8.2 Longitudinal Erosion......Page 494
15.8.3 Flow Diversion......Page 495
15.9 STORAGE HISTORY CURVES......Page 496
15.10 SCOUR CONE GEOMETRY......Page 497
15.11 COMPARTMENTED AND MULTIPLE RESERVOIRS......Page 498
15.12 PLANNING AND IMPLEMENTATION......Page 499
15.12.2 Scheduling of Flushing......Page 500
15.12.4 Sediment Release and Concentration......Page 501
15.13 LONG-TERM STORAGE CAPACITY......Page 504
15.14 CLOSURE......Page 506
16.1  INTRODUCTION......Page 507
16.2  DRY EXCAVATION......Page 508
16.2.2  Cogswell Reservoir......Page 509
16.3.1  Hydraulic Suction Dredges......Page 511
16.3.2 Siphon Dredge......Page 514
16.3.4  Cable-Suspended Dredge Pumps......Page 515
16.3.6  Sediment Removal by Explosives......Page 516
16.4 CONSIDERATIONS FOR RESERVOIR DREDGING......Page 517
16.4.2  Dredging Equipment......Page 518
16.4.3  Pipeline System......Page 520
16.4.4  Disposal Site......Page 521
16.4.5  Long-Term Use and Sustainable Dredging......Page 523
16.4.6  Dredging Contracts......Page 524
16.4.7  Permit Requirements......Page 526
16.5.1  Lake Springfield, Illinois......Page 527
16.5.2  Valdesia Reservoir, Dominican Republic......Page 528
16.5.3  Bai-Ho Reservoir, Taiwan......Page 530
16.6.1  Volume for Initial Storage......Page 531
16.6.2  General Containment Area Considerations......Page 532
16.7  COLUMN SETTLING TESTS......Page 533
16.7.1  Column Test Procedure......Page 534
16.7.2  Zone Settling Test......Page 536
16.7.3  Compression Settling Test......Page 537
16.7.4 Achievement of Strict Effluent Standards......Page 538
16.7.5  Hydraulic Efficiency......Page 539
16.7.6  Weir Length......Page 540
16.8.1  Flow Regimes......Page 541
16.9  PIPELINE HEAD LOSS......Page 544
16.9.1  Friction Losses by Slurry Density Approach......Page 545
16.9.3  Turner's Friction Loss Graph......Page 546
16.10  CLOSURE......Page 548
17.1 INTRODUCTION......Page 549
17.2 DAM REMOVAL OPTIONS......Page 550
17.2.3 Complete Dam Removal......Page 551
17.2.4 Staged Breaching......Page 552
17.3 SEDIMENT MANAGEMENT OPTIONS......Page 553
17.3.1 Leave Sediment in Place......Page 554
17.3.2 Natural Erosion......Page 555
17.3.3 Channeling and Stabilization......Page 556
17.4.1 Water and Sediment Quality......Page 558
17.4.2 Fluvial Morphology......Page 560
17.4.4 Flood Management......Page 561
17.4.8 Cost......Page 562
17.5.2 Stronach Dam......Page 563
17.5.3 North Avenue Dam, Milwaukee, Wisconsin......Page 564
17.5.4 Glines Canyon and Elwha Hydroelectric Dams, Washington State......Page 567
17.6 CLOSURE......Page 573
18.1 INTRODUCTION......Page 574
18.2.1 Dams and Environmental Impacts......Page 575
18.2.2 Economic Quantification of Environmental Impacts......Page 576
18.2.3 Hydroperiod Modification......Page 578
18.2.4 Environmental Consequences of Sediment and Its Management......Page 580
18.2.5 Morphologic Impact Downstream of Dams......Page 582
18.3 ENVIRONMENTAL IMPACTS OF SEDIMENT ROUTING......Page 587
18.3.3 Seasonally Empty Reservoir......Page 589
18.3.4 Sediment Routing on Isar River......Page 590
18.4.1 Water Quality during Reservoir Emptying......Page 592
18.4.2 Fisheries Impacts......Page 593
18.4.3 Predicting Downstream Water Quality......Page 594
18.4.4 Reservoir Ecosystem......Page 595
18.4.6 Timing, Coordination, and Public Relations......Page 596
18.4.7 Water Quality Mitigation Measures for Flushing......Page 598
18.4.8 Monitoring......Page 599
18.4.9 Flushing at Spencer Dam, Nebraska......Page 600
18.5.2 Grain Feeding in the Rhine River......Page 602
18.6.1 Importance of Gravel Flushing......Page 604
18.6.3 Planning Flushing Flows......Page 606
18.6.4 Analytical Flushing Flow Computations for Gravel Cleansing......Page 607
18.6.5 Gravel Flushing in Trinity River, California......Page 608
18.7 CLOSURE......Page 609
19.1.1 Project Description......Page 610
19.2.1 Operational Procedures......Page 613
19.2.2 Sedimentation Studies at the Reservoir......Page 617
19.3.1 Rating Curve Analysis......Page 618
19.3.2 Analysis of Computational Increment......Page 620
19.3.5 Critical Discharge Classes......Page 621
19.3.6 Turbidity Measurement......Page 622
19.3.7 Interpretation of Turbidity Data......Page 625
19.4 SEDIMENT DEPOSITION AND EROSION......Page 628
19.4.3 Grain Size Analysis......Page 629
19.4.5 Side-Scan Sonar......Page 630
19.4.6 Subbottom Profiler......Page 631
19.5.1 Erosion Processes Observed during Flushing......Page 632
19.5.2 Sediment Release during Flushing......Page 633
19.6 SEDIMENT BUDGET......Page 636
19.7 CLOSURE......Page 637
20.1 PROJECT HISTORY......Page 638
20.2 HYDROLOGY......Page 641
20.3.1 Sediment Yield......Page 642
20.3.2 Sediment Deposits......Page 644
20.3.4 Rate of Storage Loss......Page 648
20.3.5 Trends in Sediment Yield......Page 652
20.4.4 Venting Turbid Density Currents......Page 653
20.5 MODELING OF SEDIMENT ROUTING......Page 654
20.5.3 Model Calibration......Page 655
20.5.4 Modeling Results......Page 656
20.6.1 Operational Constraints......Page 657
20.6.2 Model Development......Page 658
2.6.5 Model Operation......Page 659
20.7.1 Dredging Volume......Page 660
20.7.3 Sediment Sampling......Page 661
20.9 CLOSURE......Page 662
21.1 INTRODUCTION......Page 663
21.2 ALTERNATIVES CONSIDERED......Page 664
21.3 CONFIGURATION OF LOW-LEVEL OUTLET......Page 665
21.4 FLUSHING OPERATIONS......Page 666
21.5 DOWNSTREAM IMPACTS......Page 670
22.1 INTRODUCTION......Page 673
22.2.1 Site Description......Page 674
22.2.2 Geomorphology......Page 676
22.2.3 Sediment Management History......Page 677
22.3.2 Erosion History......Page 678
22.3.4 Coordinated Resources Management Group......Page 680
22.4.1 Red Clover Creek Demonstration Project......Page 682
22.4.2 Big Flat Meadow Restoration Project......Page 686
22.5  COST AND BENEFIT OF WATERSHED RESTORATION......Page 687
22.5.1 Overview of Project Costs......Page 688
22.5.2 PG&E Economic Justification for Watershed Protection Activities......Page 689
22.7 RESERVOIR DREDGING......Page 691
22.8 SEDIMENT ROUTING......Page 693
22.8.2 Physical Modeling......Page 694
22.8.3 Numerical Modeling......Page 695
22.8.4 Selected Project Configuration......Page 697
22.9 SEDIMENT PROBLEMS AT POE DAM......Page 698
23.2.1 Dam and Reservoir......Page 700
23.2.2 Water and Sediment Inflow......Page 701
23.2.3 Sediment Deposits......Page 704
23.2.4 Turbid Density Currents......Page 705
23.3.1 Hydraulic Dredging......Page 706
23.3.4 Venting Turbid Density Currents......Page 707
23.3.6 Emptying and Flushing......Page 708
23.4.1 Reservoir Operation......Page 709
23.4.2 Sheet Erosion......Page 712
23.4.5 Outflow Sediment Concentration......Page 713
23.5 LATERAL EROSION BY PIPING......Page 716
23.6 DIVERSION CHANNEL TECHNIQUE......Page 717
23.6.1 Components of the System......Page 718
23.6.4 Operational Results......Page 719
23.6.5 Prediction of Channel Width......Page 723
23.7 ECONOMIC ANALYSIS......Page 724
23.8 CLOSURE......Page 726
24.1 INTRODUCTION......Page 727
24.2 HYDROLOGIC SETTING......Page 728
24.3 SUMMARY OF SEDIMENT CONTROL MEASURES......Page 730
24.4.1 Deposition and Flushing......Page 736
24.5 DELTA DEPOSITION AND EROSION......Page 737
24.6 TURBIDITY CURRENTS......Page 739
24.7 DEPOSITION ALONG WEI RIVER......Page 740
24.7.1 Backwater Deposition......Page 741
24.7.2 Local Deposition from Luo River......Page 742
24.8 RETROGRESSIVE EROSION......Page 743
24.9 SEDIMENT DISCHARGE DOWNSTREAM......Page 744
24.10 CLOSURE......Page 747
25.2 SITE DESCRIPTION......Page 748
25.3 SEDIMENT MANAGEMENT STRATEGIES......Page 752
25.4 WARPING......Page 753
25.5 DEPOSITION PATTERNS......Page 754
25.6.2 Detention Flushing......Page 755
25.7 TURBIDITY CURRENT VENTING......Page 758
25.8 LATERAL EROSION......Page 759
25.9 VARIATION IN SEDIMENT RELEASE EFFICIENCY......Page 762
25.9.2 Flood Detention Flushing......Page 764
25.10 CLOSURE......Page 767
REFERENCES......Page 768
A. PROPERTIES OF WATER, INTERNATIONAL  UNITS......Page 799
D. UNIT PREFIXES......Page 800
F. INTERNATIONAL AND DERIVED UNITS OF MEASURE......Page 801
G.  UNITS OF MEASURE IN BRITISH OR U.S. CONVENTIONAL UNITS (FPS SYSTEM)......Page 802
H. TABLE OF UNIT CONVERSION FACTORS......Page 803
J. STREAM POWER......Page 804