Geomorphology of Upland Peat: Erosion, Form and Landscape Change (RGS-IBG Book Series)

The Geomorphology of Upland Peat offers a detailed synthesis of existing literature on peat erosion, incorporating new research ideas and data from two leading experts in the field. Presents the most detailed and current work to date Written in a style that is both intelligent and accessible Fully illustrated with original drawings and photographs Relevant and information for a broad audience working on organic sediments in various environments Contents 8 Series Editors’ Preface 12 Acknowledgements 13 Figure and Table Acknowledgements 15 Chapter One: Introduction 20 1.1 The Aims of this Volume 20 1.1.1 Thematic coverage 20 1.1.2 Geographical context 21 1.2 Terminology, Definitions and Peatland Geomorphology 22 1.2.1 Definitions of peat 22 1.2.2 The physical and geotechnical properties of peat 25 1.2.3 Peatland classification 25 1.3 The Geography of Blanket Mire Complexes 30 1.4 Patterns of Peat Erosion in Space and Time 34 1.4.1 The onset of peat erosion 37 1.4.2 Direct observation of the onset of erosion 39 1.5 Causes of Peat Erosion 40 1.6 A Brief History of the Evolution of Peatland Geomorphology 41 1.6.1 Accounts of erosion in the natural science tradition 42 1.6.2 Descriptive accounts of widespread peat erosion 42 1.6.3 Quantitative observations of blanket peatlands 43 1.7 Structure of this Volume and the Peat Landsystem Model 45 Chapter Two: The Hydrology of Upland Peatlands 47 2.1 Introduction 47 2.2 Controls on Water Movement in Peat Landsystems 47 2.2.1 Hydraulic conductivity of upland peat soils 47 2.2.2 The diplotelmic mire hypothesis 49 2.2.3 Groundwater flow in upland peatlands 53 2.2.4 Evaporation 56 2.2.5 Runoff generation 57 2.2.6 The water balance of ombrotrophic mires 66 2.3 Geomorphology and the Hydrology of Upland Peatlands 68 Chapter Three: Sediment Production 73 3.1 Introduction 73 3.1.1 Monitoring sediment production using erosion pins 73 3.1.2 Sediment trap data 75 3.2 Sediment Production as a Control on Catchment Sediment Flux 80 3.3 Evidence from Field Observation 84 3.3.1 Climate correlations with trap data 84 3.3.2 Direct observations of surface change 86 3.4 Evidence from Controlled Experiments 88 3.5 Timescales of Sediment Supply 92 3.6 Conclusion 93 Chapter Four: Fluvial Processes and Peat Erosion 95 4.1 Introduction 95 4.2 Gully Erosion of Blanket Peat 95 4.2.1 Gully morphology and topology 96 4.2.2 Fluvial erosion in ephemeral hillslope gullies 100 4.2.3 Sediment delivery from hillslope gullies 104 4.3 Erosion and Transport of Peat in Perennial Stream Channels 106 4.3.1 Production of peat blocks by fluvial erosion 106 4.3.2 Transport of peat blocks in stream channels 110 4.3.3 The fate of fine peat sediment in channels 112 4.4 Sediment Yield 114 4.4.1 Bedload yields 114 4.4.2 Suspended sediment yields 114 4.4.3 Dissolved load 116 4.4.4 A conceptual model of sediment dynamics in eroding blanket peatlands 118 4.4.5 Sediment yield, sediment supply and assessing catchment erosion status 120 4.5 Conclusions 122 Chapter Five: Slope Processes and Mass Movements 123 5.1 Introduction 123 5.2 Peat-Covered Hillslopes 127 5.2.1 Limits to the stability of peat on slopes 127 5.2.2 Creep on peat hillslopes 130 5.3 Morphology of Rapid Peat Mass Movements 131 5.3.1 Source zone 134 5.3.2 Rafted peat debris 135 5.3.3 Runout track 135 5.3.4 Secondary tension and compression features 137 5.3.5 Bog burst and peat slides – are they different? 139 5.4 Mechanism of Peat Failure 142 5.4.1 Speed of failure and movement 144 5.5 Significance of Surface Hydrology in Peat Failures 144 5.5.1 Water content, pore pressures and volume changes 146 5.5.2 Rainfall 147 5.5.3 Slope drainage 147 5.6 Stability Analysis and Modelling of Peat Mass Movements 148 5.7 The Changing Frequency of Peat Mass Movements Over Time 150 5.8 Summary and Overall Framework 152 Chapter Six: Wind Erosion Processes 155 6.1 Introduction 155 6.2 The General Significance of Wind Erosion in Upland Peatlands 156 6.3 Mechanisms and Processes of Wind Erosion 159 6.4 Direct Measurements of Wind Erosion of Peat 165 6.5 Significance of Dry Conditions and Drought for Wind Erosion 169 6.6 Conclusions 172 Chapter Seven: Peat Erosion Forms – From Landscape to Micro-Relief 174 7.1 Rationale and Introduction 174 7.2 Macroscale – Region/Catchment Scale 177 7.3 Mesoscale – Slope Catena Scale 181 7.4 Microscale – Material Structure Scale 184 7.5 Linking the Geomorphological and the Ecohydrological 186 7.6 Conclusions 188 Chapter Eight: Sediment Dynamics, Vegetation and Landscape Change 190 8.1 Introduction 190 8.2 The Effect of Peatland Dynamics on Long-Term Sediment Budgets 191 8.3 Re-Vegetation of Eroding Peatlands 193 8.3.1 Artificial re-vegetation of bare peat surfaces 193 8.3.2 Natural re-vegetation of eroded landscapes 194 8.4 Controls and Mechanisms of Natural Re-Vegetation 197 8.4.1 Extrinsic controls on re-vegetation 197 8.4.2 Intrinsic controls on re-vegetation 200 8.4.3 Eriophorum spp. as keystone species for re-vegetation of eroded peatlands 204 8.4.4 Re-vegetation dynamics and long-term patterns of erosion 206 8.5 Stratigraphic Evidence of Erosion and Re-Vegetation 207 8.6 The Future of Blanket Peat Sediment Systems 209 8.7 Changes in Pollution 209 8.8 Climate Change Impacts 210 8.8.1 Increased summer drought 211 8.8.2 Increased winter rainfall intensity 212 8.8.3 Changes in the growing season and re-vegetation 213 8.8.4 Reduced frost frequency 213 8.8.5 Overall response of the peatland system 213 8.9 Relative Importance of Peat Erosion in Wider Upland Sediment Budgets 214 8.10 Conclusions 216 Chapter Nine: Implications and Conclusions 218 9.1 Implications of Widespread Peat Erosion 218 9.2 Upland Peatland Erosion and Carbon Budgets 218 9.2.1 Case study example: the Rough Sike carbon budget 220 9.3 Release of Stored Contaminants from Eroding Peatlands 224 9.4 Restoration of Eroded Upland Peatlands 228 9.4.1 Frameworks for restoration 228 9.4.2 Approaches to restoration 229 9.4.3 Implications of the landsystems model and sediment budget work for restoration 230 9.5 Conclusions 233 9.5.1 The nature of upland peatlands 233 9.5.2 Geomorphological processes in upland peatlands 234 9.5.3 The future of upland peatlands 235 9.5.4 Representativeness of the peatland system model 236 References 238 Index 270 Contents......Page 8 Series Editors’ Preface......Page 12 Acknowledgements......Page 13 Figure and Table Acknowledgements......Page 15 1.1.1 Thematic coverage......Page 20 1.1.2 Geographical context......Page 21 1.2.1 Definitions of peat......Page 22 1.2.3 Peatland classification......Page 25 1.3 The Geography of Blanket Mire Complexes......Page 30 1.4 Patterns of Peat Erosion in Space and Time......Page 34 1.4.1 The onset of peat erosion......Page 37 1.4.2 Direct observation of the onset of erosion......Page 39 1.5 Causes of Peat Erosion......Page 40 1.6 A Brief History of the Evolution of Peatland Geomorphology......Page 41 1.6.2 Descriptive accounts of widespread peat erosion......Page 42 1.6.3 Quantitative observations of blanket peatlands......Page 43 1.7 Structure of this Volume and the Peat Landsystem Model......Page 45 2.2.1 Hydraulic conductivity of upland peat soils......Page 47 2.2.2 The diplotelmic mire hypothesis......Page 49 2.2.3 Groundwater flow in upland peatlands......Page 53 2.2.4 Evaporation......Page 56 2.2.5 Runoff generation......Page 57 2.2.6 The water balance of ombrotrophic mires......Page 66 2.3 Geomorphology and the Hydrology of Upland Peatlands......Page 68 3.1.1 Monitoring sediment production using erosion pins......Page 73 3.1.2 Sediment trap data......Page 75 3.2 Sediment Production as a Control on Catchment Sediment Flux......Page 80 3.3.1 Climate correlations with trap data......Page 84 3.3.2 Direct observations of surface change......Page 86 3.4 Evidence from Controlled Experiments......Page 88 3.5 Timescales of Sediment Supply......Page 92 3.6 Conclusion......Page 93 4.2 Gully Erosion of Blanket Peat......Page 95 4.2.1 Gully morphology and topology......Page 96 4.2.2 Fluvial erosion in ephemeral hillslope gullies......Page 100 4.2.3 Sediment delivery from hillslope gullies......Page 104 4.3.1 Production of peat blocks by fluvial erosion......Page 106 4.3.2 Transport of peat blocks in stream channels......Page 110 4.3.3 The fate of fine peat sediment in channels......Page 112 4.4.2 Suspended sediment yields......Page 114 4.4.3 Dissolved load......Page 116 4.4.4 A conceptual model of sediment dynamics in eroding blanket peatlands......Page 118 4.4.5 Sediment yield, sediment supply and assessing catchment erosion status......Page 120 4.5 Conclusions......Page 122 5.1 Introduction......Page 123 5.2.1 Limits to the stability of peat on slopes......Page 127 5.2.2 Creep on peat hillslopes......Page 130 5.3 Morphology of Rapid Peat Mass Movements......Page 131 5.3.1 Source zone......Page 134 5.3.3 Runout track......Page 135 5.3.4 Secondary tension and compression features......Page 137 5.3.5 Bog burst and peat slides – are they different?......Page 139 5.4 Mechanism of Peat Failure......Page 142 5.5 Significance of Surface Hydrology in Peat Failures......Page 144 5.5.1 Water content, pore pressures and volume changes......Page 146 5.5.3 Slope drainage......Page 147 5.6 Stability Analysis and Modelling of Peat Mass Movements......Page 148 5.7 The Changing Frequency of Peat Mass Movements Over Time......Page 150 5.8 Summary and Overall Framework......Page 152 6.1 Introduction......Page 155 6.2 The General Significance of Wind Erosion in Upland Peatlands......Page 156 6.3 Mechanisms and Processes of Wind Erosion......Page 159 6.4 Direct Measurements of Wind Erosion of Peat......Page 165 6.5 Significance of Dry Conditions and Drought for Wind Erosion......Page 169 6.6 Conclusions......Page 172 7.1 Rationale and Introduction......Page 174 7.2 Macroscale – Region/Catchment Scale......Page 177 7.3 Mesoscale – Slope Catena Scale......Page 181 7.4 Microscale – Material Structure Scale......Page 184 7.5 Linking the Geomorphological and the Ecohydrological......Page 186 7.6 Conclusions......Page 188 8.1 Introduction......Page 190 8.2 The Effect of Peatland Dynamics on Long-Term Sediment Budgets......Page 191 8.3.1 Artificial re-vegetation of bare peat surfaces......Page 193 8.3.2 Natural re-vegetation of eroded landscapes......Page 194 8.4.1 Extrinsic controls on re-vegetation......Page 197 8.4.2 Intrinsic controls on re-vegetation......Page 200 8.4.3 Eriophorum spp. as keystone species for re-vegetation of eroded peatlands......Page 204 8.4.4 Re-vegetation dynamics and long-term patterns of erosion......Page 206 8.5 Stratigraphic Evidence of Erosion and Re-Vegetation......Page 207 8.7 Changes in Pollution......Page 209 8.8 Climate Change Impacts......Page 210 8.8.1 Increased summer drought......Page 211 8.8.2 Increased winter rainfall intensity......Page 212 8.8.5 Overall response of the peatland system......Page 213 8.9 Relative Importance of Peat Erosion in Wider Upland Sediment Budgets......Page 214 8.10 Conclusions......Page 216 9.2 Upland Peatland Erosion and Carbon Budgets......Page 218 9.2.1 Case study example: the Rough Sike carbon budget......Page 220 9.3 Release of Stored Contaminants from Eroding Peatlands......Page 224 9.4.1 Frameworks for restoration......Page 228 9.4.2 Approaches to restoration......Page 229 9.4.3 Implications of the landsystems model and sediment budget work for restoration......Page 230 9.5.1 The nature of upland peatlands......Page 233 9.5.2 Geomorphological processes in upland peatlands......Page 234 9.5.3 The future of upland peatlands......Page 235 9.5.4 Representativeness of the peatland system model......Page 236 References......Page 238 Index......Page 270

beginning With A Comprehensive Introduction To The History And Global Significance Of Peatlands, geomorphology Of Upland Peat Offers A Detailed Synthesis Of The Existing Literature On Peat Erosion, While Incorporating New Research Ideas And Data From Two Of The Leading Experts In The Field. With Damaging Effects Ranging From The Exacerbation Of Water Colour Problems And Reservoir Sedimentation, To The Disruption Of The Major Role That Peatlands Play In The Global Carbon Cycle, The Erosion Of Upland Blanket Peat Is A Critical Environmental Problem.

presenting The Most Detailed Work On The Subject To Date, This Comprehensive Summary Is Authoritative And Accessible And Adorned With Rich Illustrations, Photographs And Original Drawings. While Much Of The Research Focuses On Upland Mires In The Uk, The Novel Approaches And Techniques Presented In This Volume Will Be Of Great Interest And Benefit To Those Working In A Broader Context Of Organic Sediments In Other Environments.

With damaging effects from the exacerbation of water colour problems and reservoir sedimentation, to the disruption of the role that peatlands play in the global carbon cycle, the erosion of upland blanket peat is a critical environmental problem. This book offers an introduction to the history and global significance of peatlands Introducing the history and global significance of peatlands, this book offers a detailed synthesis of the existing literature on peat erosion, while incorporating research ideas and data from two leading experts. It is of interest to those working in a context of organic sediments in other environments Geomorphology of Upland Peat offers a detailed synthesis of existing literature on peat erosion, incorporating new research ideas and data from two leading experts in the field. This text will be relevant and informative for a broad audience working on organic sediments in various environments.