Preface xi

List of contributors xiii

1 Introduction: river confluences, tributaries and the fluvial network 1
Stephen P. Rice, Bruce L. Rhoads and André G. Roy

Introduction 1

Key aims of the book 4

Sections of the book 4

I RIVER CHANNEL CONFLUENCES 11

2 Introduction to Part I: river channel confluences 13
André G. Roy

Introduction 13

Individual chapters 15

3 Modelling hydraulics and sediment transport at river confluences 17
Pascale M. Biron and Stuart N. Lane

Introduction 17

Hydraulics 18

Bedload, suspended and solute transport 29

Conclusion 37

4 Sediment transport, bed morphology and the sedimentology of river channel confluences 45
James L. Best and Bruce L. Rhoads

Context 45

Bed morphology 46

Sediment transport 56

Sedimentology 60

Conclusions 66

5 Large river channel confluences 73
Daniel R. Parsons, James L. Best, Stuart N. Lane, Ray A. Kostachuk, Richard J. Hardy, Oscar Orfeo, Mario L. Amsler and Ricardo N. Szupiany

Introduction 73

Bed morphology 75

Flow structure at large river channel confluences 80

Flow mixing at large river confluences 85

Conclusions 87

6 Management of confluences 93
Robert Ettema

Introduction 93

Unruly confluences 95

Management approaches 103

Managing confluences for sediment transport 104

Managing confluences for ice passage 111

Summary 116

7 Unconfined confluences in braided rivers 119
Peter Ashmore and J. Tobi Gardner

Introduction 119

General characteristics and significance of confluences in braided channels 121

Confluence scour depth 125

Confluence kinetics and bar formation 128

Confluence spacing and the length-scale of braided morphology 130

Sediment transport and sediment budgets 132

Sediment sorting and alluvial deposits 135

Prospect 139

II TRIBUTARY--MAIN-STEM INTERACTIONS 149

8 Introduction to Part II: tributary--main-stem interactions 151
Stephen P. Rice

Introduction 151

Individual chapters 153

9 Spatial identification of tributary impacts in river networks 159
Christian E. Torgersen, Robert E. Gresswell, Douglas S. Bateman and Kelly M. Burnett

Introduction 159

Data and measurement 160

Analytical tools 167

Future developments and challenges 175

10 Effects of tributaries on main-channel geomorphology 183
Rob Ferguson and Trevor Hoey

Introduction 183

Conceptual considerations 185

Empirical evidence 187

Theoretical models: (1) Regime analysis of confluences 191

Theoretical models: (2) Numerical experiments with adjustable grain-size

distributions 198

Discussion 201

11 The ecological importance of tributaries and confluences 209
Stephen P. Rice, Peter Kiffney, Correigh Greene and George R. Pess

Introduction 209

Tributaries, confluences and river ecology 210

Tributaries, ecosystem functions and river management 215

Constraints on understanding and progress 217

A case study 218

Conclusion 235

12 Tributaries and the management of main-stem geomorphology 243
Frédéric Liébault, Hervé Píegay, Philippe Frey and Norbert Landon

Introduction 243

Conceptual framework for assessing the geomorphological impact of tributaries 245

Managing the geomorphological impact of tributaries 251

Conclusion 266

13 Confluence environments at the scale of river networks 271
Lee Benda

Introduction 271

River network structure and confluence environments 272

Symmetry ratios and confluence environments 273

Basin shape, network patterns and confluence environments 280

Local network geometry 284

Drainage and confluence density 284

River network scaling properties of confluence environments 285

The law of stream sizes and the spatial scale of morphological diversity related to confluences 289

Longitudinal extent and size of confluence environments 290

Stochastic watershed processes 291

The role of hierarchical branching networks 292

Discussion 295

River networks, resource management and river restoration 296

III CHANNEL NETWORKS 301

14 Introduction to Part III: channel networks 303
Bruce L. Rhoads

Introduction 303

Individual chapters 304

15 Hydrologic dispersion in fluvial networks 307
Patricia M. Saco and Praveen Kumar

Hydrologic dispersion effects on runoff response 307

Runoff response as travel-time distributions: the GIUH 309

Geomorphologic dispersion in stream networks 314

Non-linear effects and the use of hydraulic geometry relations 316

Kinematic dispersion in stream networks 318

The effect of scale and rainfall intensity on the dispersive mechanisms 320

Hillslope Dispersive effects 324

Kinematic dispersion effects using the meta-channel approach 329

Summary and future research directions 331

16 Sediment delivery: new approaches to modelling an old problem 337
Hua Lu and Keith Richards

Introduction 337

The concept of sediment delivery 340

Difficulties in measuring and estimating sediment yield and SDR 341

Links between hydrology and sediment production and yield 347

Physical inferences of sediment delivery based on a simple lumped model 352

Practical large-scale application using a distributed model 358

Conclusions 361

17 Numerical predictions of the sensitivity of grain size and channel slope to an increase in precipitation 367
Nicole M. Gasparini, Rafael L. Bras and Gregory E. Tucker

Introduction 367

Landscape-evolution models 370

Example simulation of network evolution 376

Discussion 386

Conclusions 388

18 Solute transport along stream and river networks 395
Michael N. Gooseff, Kenneth E. Bencala and Steven M. Wondzell

Introduction 395

Review of current knowledge 396

Linking transport processes with the fluvial geomorphic template 404

Forward-looking perspective 410

19 Fluvial valley networks on Mars 419
Rossman P. Irwin III, Alan D. Howard and Robert A. Craddock

Introduction 419

Early observations 421

Distribution, age, origin and morphology of valley networks 422

Morphometry 432

Alluvial deposits 436

Hydrology 438

Summary 442

Acknowledgements 442

References 442

Subject Index 453

Place Index 457

River Confluences, Tributaries and the Fluvial Network is a comprehensive overview of the subject, bringing together, for the first time, state-of-the-art thinking on confluence dynamics, tributary impacts and river network functions. The book is unique in its focus, content and scope and in considering geomorphological, engineering and ecological approaches to this important aspect of river system science.

The text is written by an international team of experts who have set the research agenda in this field and who continue to make significant, ground-breaking contributions. Each chapter includes a comprehensive review of work to date, defines the current state of understanding, and introduces new, cutting-edge research and numerous global case studies. The collection provides a benchmark reference and a forward-looking assessment of the state of the science that maps out the key challenges and research questions that lie ahead.

An invaluable reference for postgraduates and researchers in the fields of fluvial geomorphology, sedimentology, ecology, hydrology, river management and engineering. The book will also be of interest to professional geoscientists, engineers and ecological consultants, looking for an up-to-date overview of the subject.

• Multi-authored work, written by leading international experts in the field
• Includes previously unpublished research and case studies
• Global examples to illustrate the various approaches to the study of confluences, tributaries and networks