Sedimentary Crisis at the Global Scale 2: Deltas, A Major Environmental Crisis (Geosciences Series)

The great deltas of the globe have been threatened for several decades but their decline now appears to be inevitable; they are receding and losing the fertility that supports their tens of millions of inhabitants. Our deltas are victims of the dramatic deterioration in the volume of continental sediment brought by rivers to the oceans. By nature, deltas are fragile eco- and geological organisms. For centuries, they have been subject to human actions in the Mediterranean and European world, and today a deep crisis is affecting the great tropical deltas. A chapter is also devoted to concerns facing the Mississippi, an "aging delta of the new world". Sedimentary Crisis at the Global Scale 2 discusses possible strategies to protect the deltas of the world – or at least adapt them and their dependencies to the changes they face. Several models are possible, including comprehensive protection (such as in the Netherlands) and cautious and respectful opening to the forces of the oceans in an environment-first perspective. Cover......Page 1 Half-Title Page......Page 2 Dedication......Page 3 Title Page......Page 4 Copyright Page......Page 5 Contents......Page 6 Introduction......Page 10 1. Deltas: Young, Fragile and Threatened Environments......Page 14 1.1.2. Dynamics of construction and redistribution in progress......Page 15 1.1.3. Young and unstable areas......Page 18 1.2.1. The Lena Delta......Page 21 1.2.2. The Mackenzie Delta......Page 22 1.3.1. The rise in sea levels......Page 24 1.3.2. Sedimentary exhaustion of continents......Page 26 1.3.3. Extraction of resources and accelerated subsidence of deltas......Page 28 1.4.2. Urbanized deltas in Southeast Asia......Page 29 1.5. Conclusion......Page 38 2.1. Some vulnerable deltas in the Holocene during the long and medium terms......Page 39 2.1.1. The Nile Delta, a condensed version of the history of the African climate......Page 40 2.1.2. The lower Huang-He and its delta: a Holocene metamorphosis under anthropological control......Page 41 2.1.3. The Rhône Delta during the Holocene: fluvial branches and the coastline record the history of its climate and society......Page 47 2.2.1. The fight against fluvial floods......Page 48 2.2.2. Hydraulic works and environmental objectives in the dyked zone......Page 51 2.2.3. What kind of compatibility or synergy takes place between fluvial restoration and protection against flooding?......Page 53 2.2.4. Defense of the Netherlands against the sea......Page 54 2.3.1. A delta with a reprieve: the Nile Delta......Page 59 2.3.2. The Rhône Delta: changes in the basin and the delta......Page 64 2.3.3. The Ebro Delta: alone against the sea......Page 66 2.3.4. The delta of the Po plain: historical dispersion of weak points......Page 69 2.3.5. The Danube Delta: still room for hope......Page 71 2.4. Conclusion......Page 73 3.1. A delta that is both open and alive: the Ganges and Brahmaputra Delta......Page 75 3.1.1. Rivers and a delta......Page 76 3.1.2. The Ganges–Brahmaputra–Meghna plain, the most populated and the poorest on Earth......Page 77 3.2.1. A technical machine, constantly more complex......Page 90 3.2.2. Extremely worrying emerging factors......Page 99 3.2.3. What will be the management choices in the future? Giving preference to the scale of the basin......Page 107 3.3.1. The deltaic zone......Page 109 3.3.2. The effects of the extraction of hydrocarbons on the environment......Page 110 3.3.3. Serious social and political stakes at play......Page 113 3.4.2. The deleterious effects of dams on water and sediment fluxes......Page 115 3.4.3. A serious environmental, economic and social crisis......Page 116 3.5.1. Burma, a country on the cusp of development......Page 118 3.5.3. The delta: crisis or stability?......Page 119 3.6. Conclusion......Page 121 4.1.1. “Discovering” the river......Page 123 4.1.2. At the origins of New Orleans......Page 124 4.1.3. An area with serious issues at stake......Page 125 4.2.1. Initial protections......Page 128 4.2.2. The beginning of generalized protections......Page 129 4.2.3. The 1927 flood in the Mississippi valley......Page 130 4.2.4. The Jadwin plan (1928)......Page 131 4.3. The “deltas” in the lower Mississippi valley, from wilderness to the current crisis......Page 132 4.4.1. Flow and landscape dynamics......Page 136 4.4.2. The Atchafalaya and its deltaic lobes......Page 139 4.4.3. The conversion of delta marshes into free water and coastal regression......Page 141 4.5.1. Hurricane Katrina......Page 144 4.5.2. What does the future hold for New Orleans?......Page 146 4.6.1. Simply a reduction in inputs or a sediment deficit?......Page 149 4.6.3. Reconstruction of the marshes......Page 150 4.6.4. Sedimentary management of deltaic branches and the future of the marshes......Page 151 4.6.5. Coastal protection plan......Page 152 4.7. Conclusion......Page 153 5.1.1. The progress of analytical approaches adds complexity to the understanding of deltas on a global scale......Page 155 5.1.2. The unforeseen effects of scientific choices......Page 157 5.1.3. Open, vulnerable systems......Page 159 5.2.1. Situations involving crises and knowledge......Page 160 5.2.2. Contemporary hydraulic engineering pitted against the dynamics of economic domination......Page 161 5.2.3. Scientific knowledge at the service of policies on rivers and on their deltas: the case of the Mekong......Page 163 5.2.4. Avatars and tribulations of geopolitics......Page 165 5.2.5. Expert appraisal and conquest of engineering markets on deltaic land......Page 166 5.3.1. The typology of deltas as a function of the changes expected in the risk profile......Page 170 5.3.2. Typology of deltas as a function of their energy consumption......Page 171 5.3.3. The degree of vulnerability or the relative vulnerability of deltas to current changes......Page 172 5.3.4. The notion of the tipping point of a delta and of the socioeconomic system......Page 173 5.4.1. Implementation of actions of sedimentary management......Page 174 5.4.2. Establishment of current and future sediment budgets......Page 177 5.5.1. Structural solutions: dykes and fluvial levees......Page 178 5.5.2. Some solutions for correction of the sedimentary deficit of deltaic plains......Page 181 5.5.3. The sustainable solutions......Page 183 Conclusion......Page 188 Glossary......Page 190 References......Page 195 Index of Place Names......Page 215 Index of Common Words......Page 220 Other titles from iSTE......Page 223 Volume 1: "The Earth's oceans are currently undergoing unprecedented changes: rivers have suffered a severe reduction in their sediment transport, and as a result, sediment input to the oceans has dropped lower than ever before. These inputs have varied over millennia as a result of both natural occurrences and human actions, such as the building of dams and the extraction of materials from riverbeds. Sedimentary Crisis at the Global Scale 1 examines how river basins have been affected by the sedimentary crises of various historical epochs. By studying global balances, it provides insights into the profound disruption of the solid transport of fluvial bodies. The book also explores studies of various rivers, from the Amazon, which remains relatively unaffected, to dying rivers such as the Colorado and the Nile."-- Back cover 1.3.1. The rise in sea levels1.3.2. Sedimentary exhaustion of continents; 1.3.3. Extraction of resources and accelerated subsidence of deltas; 1.4. Subsiding deltas in Southeast Asia; 1.4.1. An example of a young, mainly rural delta, the Huang-He; 1.4.2. Urbanized deltas in Southeast Asia; 1.5. Conclusion; 2. Old Societies and Deltaic Crises; 2.1. Some vulnerable deltas in the Holocene during the long and medium terms; 2.1.1. The Nile Delta, a condensed version of the history of the African climate La page de présentation indique : "The great deltas of the globe have been threatened for several decades but their decline now appears to be inevitable; they are receding and losing the fertility that supports their tens of millions of inhabitants. Our deltas are victims of the dramatic deterioration in the volume of continental sediment brought by rivers to the oceans."