Filling a niche in the geomorphology teaching market, this introductory book is built around a 12 week course in fluvial geomorphology.
‘Reading the landscape’ entails making sense of what a riverscape looks like, how it works, how it has evolved over time, and how alterations to one part of a catchment may have secondary consequences elsewhere, over different timeframes. These place-based field analyses are framed within their topographic, climatic and environmental context. Issues and principles presented in the first part of this book provide foundational understandings that underpin the approach to reading the landscape that is presented in the second half of the book. In reading the landscape, detective-style investigations and interpretations are tied to theoretical and conceptual principles to generate catchment-specific analyses of river character, behaviour and evolution, including responses to human disturbance.
This book has been constructed as an introductory text on river landscapes, providing a bridge and/or companion to quantitatively-framed or modelled approaches to landscape analysis that are addressed elsewhere. Key principles outlined in the book emphasise the importance of complexity, contingency and emergence in interpreting the character, behaviour and evolution of any given system.
The target audience is second and third year undergraduate students in geomorphology, hydrology, earth science and environmental science, as well as river practitioners who use geomorphic understandings to guide scientific and/or management applications.
The primary focus of Kirstie and Gary’s research and teaching entails the use of geomorphic principles as a tool with which to develop coherent scientific understandings of river systems, and the application of these understandings in management practice. Kirstie and Gary are co-developers of the River Styles® Framework and Short Course that is widely used in river management, decision-making and training.
Table of Contents
Preface xi
Acknowledgements xiv
1 Geomorphic analysis of river systems: an approach to reading the landscape 1
Introduction 1
How is geomorphology useful? 2
Geomorphic analysis of river systems: our approach to reading the landscape 3
Key messages from this chapter 7
2 Key concepts in river geomorphology 9
Introduction 9
Spatial considerations in reading the landscape 9
Catchment linkages and (dis)connectivity 14
Conceptualisation of time 17
Differentiating behaviour from change 21
Disturbance events 22
Magnitude–frequency relationships in river systems 23
River sensitivity and resilience 25
Catchment-specific analysis of river systems: combining spatial and temporal concepts 26
Conclusion 27
Key messages from this chapter 27
3 Catchment-scale controls on river geomorphology 29
Introduction: what is a catchment? 29
Process zones in catchments: sediment source, transfer and accumulation zones 29
Longitudinal profiles of rivers 31
Geomorphic transitions along river longitudinal profi les 32
Catchment morphometrics as controls on river character and behaviour 34
Geologic controls on drainage network form, and river character and behaviour 37
The influence of catchment configuration upon flow and sediment flux 41
Conclusion 42
Key messages from this chapter 42
4 Catchment hydrology 44
Introduction: what is hydrology? 44
The hydrological cycle 44
Operation of the hydrological cycle 45
Runoff generation 47
Groundwater flows 49
Catchment-scale runoff and discharge generation models 50
Channel initiation 51
Gully and channel formation 51
Flow regimes of perennial, intermittent and ephemeral rivers 53
Discharge and the magnitude/frequency of flow in river systems 54
Flood stages and hydrographs 56
Analysis of hydrograph shape 58
Discharge measurement 59
Flow frequency 60
Flow variability 61
Conclusion 62
Key messages from this chapter 62
5 Impelling and resisting forces in river systems 65
Introduction 65
Impelling and resisting forces and Lane’s balance of erosion and deposition in channels 65
Mechanics of fluid flow 67
Impelling forces in river channels 68
Resisting forces in channels 70
Vegetation and wood as resistance elements in river systems 72
Manning’s n as a unifying roughness parameter 75
The balance of impelling and resisting forces along longitudinal profiles 77
Conclusion 79
Key messages from this chapter 79
6 Sediment movement and deposition in river systems 81
Introduction 81
Grain size (sediment calibre) and definitions of bedload, mixed load and suspended load in rivers 81
Phases of sediment movement along rivers: the Hjulström diagram 84
Entrainment of sediment in river channels 85
Transport of sediment in river channels 88
Material properties that affect sediment movement in river systems 93
Deposition in river systems 102
Interpreting sediment sequences as a tool to read the landscape 104
Conclusion 114
Key messages from this chapter 114
7 Channel geometry 116
Introduction 116
Bed and bank processes that influence channel shape 117
Channel shape: putting the bed and banks together 124
Hydraulic geometry and adjustments to channel morphology 127
Conclusion 131
Key messages from this chapter 131
8 Instream geomorphic units 132
Introduction 132
Categories of geomorphic units and measures used to identify them in the field 133
Process–form associations of instream geomorphic units 134
Unit and compound instream geomorphic units 151
Forced instream geomorphic units 151
The continuum of instream geomorphic units and transformations in type 152
Conclusion 153
Key messages from this chapter 154
9 Floodplain forms and processes 155
Introduction 155
Floodplain formation processes 156
Floodplain reworking processes 159
Floodplain geomorphic units 164
The energy spectrum of floodplain types 171
Conclusion 172
Key messages from this chapter 173
10 River diversity 174
Introduction 174
Framing rivers as assemblages of cross-scalar features 176
Defining reach boundaries 176
The continuum of river form 177
The spectrum of river diversity 178
Discriminating among river types 192
The River Styles framework 199
Tips for reading the landscape to interpret river diversity 201
Conclusion 203
Key messages from this chapter 203
11 River behaviour 205
Introduction 205
River behaviour versus river change 206
Dimensions of river adjustment 207
Natural capacity for adjustment of differing river types 209
Controls on the natural capacity for adjustment of different river types 210
Interpreting the behavioural regime of different river types by reading the landscape 212
Examples of behavioural regimes for differing types of rivers 214
Analysis of river behaviour using the river evolution diagram 222
Predicting river responses to altered flux boundary conditions 229
Tips for reading the landscape to interpret river behaviour 231
Conclusion 233
Key messages from this chapter 233
12 River evolution 235
Introduction 235
Timescales of river adjustment 236
Pathways and rates of river evolution 237
Geologic controls upon river evolution 239
Climatic influences on river evolution 241
Landscape memory: imprint of past geologic and climatic conditions upon contemporary river processes, forms and evolutionary trajectory 244
River responses to altered boundary conditions 246
Linking river evolution to the natural capacity for adjustment: adding river change to the river evolution diagram 255
Reading the landscape to interpret river evolution 261
Tips for reading the landscape to interpret river evolution 265
Conclusion 267
Key messages from this chapter 267
13 Human impacts on river systems 269
Introduction 269
Historical overview of human impacts upon river systems 270
Direct and indirect forms of human disturbance to rivers 272
Conceptualising river responses to human disturbance: adding human disturbance to the river evolution diagram 282
Assessing geomorphic river condition and recovery potential 290
Tips for reading the landscape to interpret human impacts on river systems 293
Conclusion 295
Key messages from this chapter 295
14 Sediment flux at the catchment scale: source-to-sink relationships 297
Introduction 297
Conceptualising sediment flux through catchments 297
Techniques used to construct a sediment budget 298
Controls upon sediment flux 302
Analysis of sediment flux across various scales 309
Tips for reading the landscape to interpret catchment-scale sediment flux 315
Conclusion 318
Key messages from this chapter 318
15 The usefulness of river geomorphology: reading the landscape in practice 320
Introduction 320
Respect diversity 321
Understand system dynamics and evolution 321
Know your catchment 322
Closing comment: how the book should be used 323
References 324
Selected readings 328
Index 335
The color plate section can be found between pages 194 and 195
