Estuarine Ecohydrology (eBook)

Cover 1
About the Author 6
Table of Contents 8
Chapter 1 Introduction 12
1.1. What is an estuary? 12
1.2. Humanity and estuaries 13
1.2.1. Sedimentation from sediment eroded from cleared land in the hinterland 13
1.2.2. Overfishing and trawling 15
1.2.3. Destruction of wetlands 16
1.2.4. Eutrophication 16
1.2.5. Pollution 19
1.2.6. Dams 20
1.2.7. Dykes for flood protection 21
1.2.8. Human health risks 21
1.3. The future of estuaries and the quality of life of the human population living on its shores 22
1.4. The solution 23
1.5. Ecohydrology science: the structure of this book 25
Chapter 2 Estuarine water circulation 28
2.1. The average residence time 28
2.2. The age of water 29
2.3. Exposure time vs. residence time 32
2.4. Vertical mixing and stratification 34
2.5. Lateral stratification, trapping, and shear 39
2.6. The importance of the bathymetry on flushing 42
2.7. The importance of flows near the river mouth on flushing 47
2.8. The special case of lagoons 50
Chapter 3 Estuarine sediment dynamics 52
3.1. Geomorphological time scales 52
3.2. Sediment dynamics 56
3.2.1. The distinction between mud, silt and sand 56
3.2.2. Sand dynamics 58
3.2.3. Mud dynamics 60
3.2.4. Engineering implications 68
3.2.5. Biological implications 68
3.3. Net sediment budgets 70
3.3.1. The age of estuaries 70
3.3.2. Net erosion or progradation 71
3.3.3. Formation of mudflats 74
3.3.4. Formation of tidal wetlands by the vegetation colonizing bare intertidal areas 76
3.4. The size of the mouth 79
Chapter 4 Tidal wetlands 82
4.1. Description 82
4.2. Hydrodynamics 85
4.3. Wave attenuation by wetland vegetation 87
4.4. Ecological processes within a tidal wetland 89
4.4.1. Mangroves 90
4.4.2. Saltmarshes 92
4.4.3. Supratidal mudflats 93
4.5. Enhancement of estuarine fisheries productivity by outwelling from tidal wetlands 94
4.6. Groundwater flow 96
4.6.1. Mangroves 96
4.6.2. Saltmarshes 98
4.7. Physics-biology links 98
Chapter 5 Estuarine food webs 102
5.1. Simple food webs 102
5.1.1. Definitions 102
5.1.2. Clear waters 104
5.2. The key role of detritus 104
5.3. The role of groundwater 108
5.4. Link to pelagic food web (fisheries) 108
5.5. Estuarine ecology 109
5.6. Over-stressed ecosystems 111
5.7. Seagrass and coral reefs 115
Chapter 6 Ecohydrology models 118
6.1. Engineering models 119
6.2. Ecosystem models 122
6.2.1. Predator-prey relationship 122
6.2.2. Estuarine ecosystem models 124
6.2.3. An estuarine ecohydrology model 125
6.3. Coral reef ecohydrology model 131
Chapter 7 Ecohydrology solutions 136
7.1. Freshwater 136
7.2. Estuaries 137
7.3. Coastal waters 138
7.4. Managing human health threats 139
7.5. Habitat creation 140
7.5.1. Saltmarshes 140
7.5.2. Mangroves 142
7.5.3. Seagrass 143
7.5.4. Coral reefs 143
7.5.5. Sediment capping 144
7.6. Protection against natural hazards 144
7.7. A future for estuaries and coastal waters? 146
References 150
Index 166