Introducing Large Rivers

Preface xiii 1 Introduction 1 1.1 Large Rivers 1 1.2 A Book on Large Rivers 3 References 6 2 Geological Framework of Large Rivers 7 2.1 Introduction 7 2.2 The Geological Framework: Elevated Land and a Large Catchment 8 2.3 Smaller Tectonic Movements 9 2.4 The Subsurface Alluvial Fill of Large Rivers 10 2.5 Geological History of Large Rivers 12 2.6 Conclusion 14 Questions 14 References 14 3 Water and Sediment in Large Rivers 17 3.1 Introduction 17 3.2 Discharge of large Rivers 17 3.3 Global Pattern of Precipitation 18 3.4 Large River Discharge: Annual Pattern and Long-Term Variability 21 3.5 Sediment in Large Rivers 26 3.6 Conclusion 32 Questions 32 References 33 4 Morphology of Large Rivers 35 4.1 Introduction 35 4.2 Large Rivers from Source to Sink 35 4.3 The Amazon River 38 4.3.1 The Setting 39 4.3.2 Hydrology 39 4.3.3 Sediment Load 39 4.3.4 Morphology 42 4.4 The Ganga River 44 4.4.1 The Setting 44 4.4.2 Hydrology 46 4.4.3 Sediment Load 46 4.4.4 Morphology 47 4.5 Morphology of Large Rivers: Commonality and Variations 48 4.6 Conclusion 52 Questions 52 References 52 5 Large Rivers and their Floodplains: Structures, Functions, Evolutionary Traits and Management with Special Reference to the Brazilian Rivers 55 Wolfgang J. Junk, Florian Wittmann, Jochen Schöngart, Maria Teresa F. Piedade and Catia Nunes da Cunha 5.1 Introduction 55 5.2 Origin and Age of Rivers and Floodplains 57 5.3 Scientific Concepts and their Implications for Rivers and Floodplains 59 5.4 Water Chemistry and Hydrology of Major Brazilian Rivers and their Floodplains 60 5.5 Ecological Characterisation of Floodplains and their Macrohabitats 62 5.6 Ecological Responses of Organisms to Flood-Pulsing Conditions 64 5.6.1 Trees 65 5.6.2 Herbaceous Plants 66 5.6.3 Invertebrates 66 5.6.4 Fish 67 5.6.5 Other Vertebrates 68 5.7 Biodiversity 68 5.7.1 Higher Vegetation 69 5.7.2 Animal Biodiversity 71 5.8 The Role of Rivers and their Floodplains for Speciation and Species Distribution of Trees 71 5.9 Biogeochemical Cycles in Floodplains 73 5.9.1 Biomass and Net Primary Production 73 5.9.1.1 Algae 73 5.9.1.2 Herbaceous Plants 74 5.9.1.3 Trees of the Flooded Forest 75 5.9.2 Decomposition 76 5.9.3 The Nitrogen Cycle 77 5.9.4 Nutrient Transfer Between the Terrestrial and Aquatic Phases 78 5.9.5 Food Webs 79 5.10 Management of Amazonian River Floodplains 80 5.10.1 Amazonian River Floodplains 80 5.10.2 Savanna Floodplains 82 5.11 Policies in Brazilian Wetlands 82 5.12 Discussion and Conclusion 84 Acknowledgements 89 References 89 6 Large River Deltas 103 6.1 Introduction 103 6.2 Large River Deltas: The Distribution 104 6.3 Formation of Deltas 104 6.4 Delta Morphology and Sediment 110 6.5 The Ganga-Brahmaputra Delta: An Example of a Major Deltaic Accumulation 112 6.5.1 The Background 112 6.5.2 Morphology of the Delta 113 6.5.3 Late Glacial and Holocene Evolution of the Delta 114 6.6 Conclusion 115 Questions 115 References 116 7 Geological History of Large River Systems 119 7.1 The Age of Large Rivers 119 7.2 Rivers in the Quaternary 121 7.2.1 The Time Period 121 7.2.2 The Nature of Geomorphic Changes 123 7.2.3 The Pleistocene and Large Rivers 124 7.2.3.1 The Glacial Stage 124 7.2.3.2 The Transition 125 7.2.3.3 The Interglacial Stage 127 7.3 Changes During the Holocene 127 7.4 Evolution and Development of the Mississippi River 128 7.5 The Ganga-Brahmaputra System 133 7.6 Evolution of the Current Amazon 137 7.7 Evolutionary Adjustment of Large Rivers 141 Questions 142 References 142 8 Anthropogenic Alterations of Large Rivers and Drainage Basins 147 8.1 Introduction 147 8.2 Early History of Anthropogenic Alterations 148 8.3 The Mississippi River: Modifications before Big Dams 149 8.4 The Arrival of Large Dams 151 8.5 Evaluating the Impact of Anthropogenic Changes 156 8.5.1 Land Use and Land Cover Changes 157 8.5.2 Channel Impoundments 159 8.6 Effect of Impoundments on Alluvial Rivers 161 8.7 Effect of Impoundments on Rivers in Rock 163 8.8 Large-scale Transfer of River Water 166 8.9 Conclusion 167 Questions 168 References 169 9 Management of Large Rivers 173 9.1 Introduction 173 9.2 Biophysical Management 177 9.3 Social and Political Management 178 9.3.1 Values and Objectives in River Management 179 9.3.2 International Basin Arrangements 180 9.4 The Importance of the Channel, Floodplain, and Drainage Basin 180 9.5 Integrated Water Resources Management 182 9.6 Techniques for Managing Large River Basins 183 9.7 Administering the Nile 184 9.8 Conclusion 188 Questions 189 References 190 10 The Mekong: A Case Study on Morphology and Management 193 10.1 Introduction 193 10.2 Physical Characteristics of the Mekong Basin 194 10.2.1 Geology and Landforms 194 10.2.2 Hydrology 196 10.2.3 Land Use 197 10.3 The Mekong: Source to Sea 199 10.3.1 The Upper Mekong in China 199 10.3.2 The Lower Mekong South of China 199 10.4 Erosion, Sediment Storage and Sediment Transfer in the Mekong 202 10.5 Management of the Mekong and its Basin 204 10.5.1 Impoundments on the Mekong 204 10.5.2 Anthropogenic Modification of Erosion and Sedimentation on Slopes 206 10.5.3 Degradation of the Aquatic Life 207 10.6 Conclusion 208 Questions 208 References 209 11 Large Arctic Rivers 211 Olav Slaymaker 11.1 Introduction 211 11.1.1 The Five Largest Arctic River Basins 213 11.1.2 Climate Change in the Five Large Arctic Basins 213 11.1.3 River Basin Zones 214 11.2 Physiography and Quaternary Legacy 216 11.2.1 Physiographic Regions 216 11.2.1.1 Active Mountain Belts and Major Mountain Belts with Accreted Terranes (Zone 1) 216 11.2.1.2 Interior Plains, Lowlands, and Plateaux (Zone 2) 217 11.2.1.3 Arctic Lowlands (Zone 3) 218 11.2.2 Ice Sheets and Their Influence on Drainage Rearrangement 218 11.2.3 Intense Mass Movement on Glacially Over-steepened Slopes 218 11.3 Hydroclimate and Biomes 220 11.3.1 Climate Regions 220 11.3.2 Biomes 220 11.3.3 Wetlands 224 11.4 Permafrost 224 11.4.1 Permafrost Distribution 224 11.4.2 Permafrost and Surficial Materials 226 11.4.3 Contemporary Warming 226 11.5 Anthropogenic Effects 228 11.5.1 Development and Population 228 11.5.2 Agriculture and Extractive Industry 228 11.5.3 Urbanisation: The Case of Siberia 228 11.6 Discharge of Large Arctic Rivers 229 11.6.1 Problems in Discharge Measurement 229 11.6.2 Water Fluxes 229 11.6.3 Water Budget 231 11.6.4 Nival River Regime 232 11.6.5 Lakes and Glaciers 234 11.6.6 River Ice: Freeze and Break Up 236 11.6.7 Scale Effects 237 11.6.8 Effects of River Regulation 238 11.6.9 Historical Changes 238 11.7 Sediment Fluxes 239 11.7.1 Complications in Determining Sediment Fluxes Both Within Arctic Basins and to the Arctic Ocean 239 11.7.2 Flux of Suspended Sediment and Dissolved Solids 240 11.7.3 Historical Changes in Water and Sediment Discharge in the Siberian Rivers 240 11.7.4 Suspended Sediment Sources and Sinks in the Mackenzie Basin 242 11.7.4.1 Sediment Yield in the Mackenzie Basin 242 11.7.4.2 West Bank Tributary Sources 243 11.7.4.3 Bed and Bank Sources 245 11.8 Nutrients and Contaminants 249 11.8.1 Supply of Nutrients 249 11.8.2 Transport of Contaminants 250 11.9 Mackenzie, Yukon and Lena Deltas 253 11.9.1 Mackenzie Delta 253 11.9.2 Lena Delta 253 11.9.3 Yukon–Kuskokwim Delta 256 11.10 Significance of Large Arctic Rivers 256 Acknowledgment 258 Questions 259 References 259 12 Climate Change and Large Rivers 265 12.1 Introduction 265 12.2 Global Warming: Basic Concept 266 12.3 A Summary of Future Changes in Climate 270 12.4 Impact of Climate Change on Large Rivers 271 12.5 Climate Change and a Typical Large River of the Future 273 12.6 Conclusion 277 Questions 277 References 278 Index 281