Download or read book Impact de l urbanisation sur la r ponse hydrologique des bassins versants urbains written by Bahar Salavati and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'urbanisation a de multiples impacts sur les processus hydrologiques. A l'échelle du bassin versant, ces impacts sont difficiles à quantifier et les résultats de la littérature sur ce sujet sont assez disparates. L'objectif de cette thèse est d'analyser conjointement l'évolution de l'urbanisation et l'évolution des écoulements des bassins versants. La détection et la quantification des changements d'écoulement potentiellement liés à l'urbanisation des bassins nécessitent de distinguer les changements de débits liés à l'urbanisation de ceux liés à d'autres facteurs de variabilité hydrologique, tels que le climat. Ceci soulève plusieurs questions liées notamment à la relation entre la variabilité du climat et celle de la réponse hydrologique des bassins, et aussi à la détermination d'une mesure de l'urbanisation utile pour l'hydrologie. Pour répondre à ces questions, plusieurs approches ont été testées : 1) Nous avons analysé la fiabilité d'un modèle hydrologique pour simuler l'impact de l'urbanisation. Pour cela, nous avons utilisé la technique des bassins versants appariés : un bassin versant urbanisé proche d'un autre bassin versant non-urbanisé servant de témoin permet d'évaluer l'impact de l'urbanisation sur la réponse hydrologique des bassins. 2) Nous nous sommes également intéressés à la caractérisation de l'urbanisation par des mesures de structure du paysage urbain, en complément de mesures plus classiques (imperméabilité et fraction de surface urbaine). 3) Nous avons ensuite étudié les variables qui expliquent le mieux chaque variable hydrologique de bassin (module et débits caractéristiques de crue et d'étiage. 4) Nous avons enfin utilisé un modèle hydrologique permettant de synthétiser le comportement du bassin versant au cours e son urbanisation.Les résultats ont montré que l'approche par modélisation hydrologique permettait de quantifier d'une façon satisfaisante l'impact du changement d'occupation du sol. Cette approche par modélisation donne des résultats proches de celle par bassins appariés. La thèse met également en évidence que l'impact de l'urbanisation sur la réponse hydrologique du bassin versant reste difficile à généraliser. En effet, une majorité de bassins versants urbains ne présente pas de tendance significative sur les caractéristiques hydrologiques analysées (débits caractéristiques de crue et d'étiage). Enfin, les caractéristiques de fragmentation du paysage urbain fournissent des éléments complémentaires aux mesures plus classiques de l'urbanisation.
Download or read book Repr sentation de l urbanisation dans la mod lisation hydrologique l chelle du bassin versant written by Mohamed Saadi and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Afin de déterminer l'impact hydrologique de l'étalement urbain à venir, la modélisation hydrologique est très utile car elle permet de traduire les scénarios d'urbanisation en scénarios hydrologiques en tenant compte de la variabilité climatique. Malgré la diversité actuelle des modèles hydrologiques applicables sur les bassins urbanisés, ces modèles sont en général développés sur un nombre limité de bassins versants, ce qui pose la question de leur robustesse. L'objectif de cette thèse est de chercher une structure de modèle hydrologique capable de reproduire la relation pluie-débit pour un large échantillon de bassins versants urbanisés, situés en France et aux États-Unis, et caractérisés par différents niveaux d'étalement urbain. Pour ce faire, nous sommes partis d'une structure de modèle conceptuel (GR4H), fonctionnant au pas de temps horaire mais non dédiée aux bassins versants urbanisés. Pour arriver à nos objectifs, nous avons considéré quatre étapes : (1) la collecte et la préparation d'un large échantillon de données pour plus de 2000 bassins versants situés en France et aux États-Unis. L'analyse de la variabilité des coefficients de ruissellement de 852 bassins nord-américains a montré une dépendance non seulement au taux moyen d'imperméabilité totale (TIA), mais aussi aux conditions d'humidité du sol quel que soit le niveau d'étalement urbain du bassin versant ; (2) le test de la structure de départ sur les bassins fortement urbanisés. Cette étape a montré l'aptitude des paramètres du modèle GR4H à traduire les spécificités du comportement hydrologique en contexte urbanisé ; (3) la régionalisation des paramètres de la structure de départ GR4H pour les lier à la fraction du couvert urbain. Les relations de régression obtenues ont été performantes mais peu sensibles à la caractérisation du couvert urbain ; (4) la modification pas-à-pas de la structure de GR4H en rajoutant le ruissellement sur les surfaces imperméables, et en variant le partage entre écoulement rapide et écoulement lent en fonction de chaque bassin. L'évaluation de ces modifications sur 273 bassins versants urbanisés a indiqué une amélioration de la simulation des écoulements surtout lors des périodes sèches et des périodes de crue. Les paramètres rajoutés ont montré une forte dépendance au taux moyen d'imperméabilité totale. Les travaux de cette thèse montrent un exemple de démarche constructive de développement de modèle hydrologique, par laquelle nous avons réussi à améliorer la représentation de l'urbanisation au sein du modèle tout en obtenant de meilleurs résultats en comparant avec des séries observées. Un effort de régionalisation de la nouvelle structure en exploitant des mesures de fragmentation du paysage urbain permettra une étude d'impact de différents schémas d'urbanisation future sur la réponse hydrologique.
Download or read book Effects of Urbanization and Industrialization on the Hydrological Regime and on Water Quality Symposium written by International Association of Hydrological Sciences and published by . This book was released on 1977 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pollution Hydrologique Urbaine Et Impacts written by Ndjama Josephine and published by Editions Universitaires Europeennes. This book was released on 2015-01-30 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: La demographie galopante et l'urbanisation croissante du Cameroun posent de nombreux problemes de pollution dans les ecosystemes urbains. Cette pollution est visiblement plus accentuee dans les grandes metropoles du Cameroun ainsi que ces impacts nefastes sur l'environnement. Pour repondre a ces preoccupations, la presente recherche a ete menee dans le bassin versant de la Mgoua a Douala par une etude socio-economique, ensuite l'analyse des parametres physico-chimiques et microbiologiques des eaux et des sediments. Il apparait que la plupart des populations s'approvisionnent dans les puits. Les resultats obtenus presentent des nombreux cas de maladies hydriques ainsi que celles de la peau. Les cours d'eau et les puits sont plus pollues que les effluents. Les pollutions fecales des cours d'eau et des puits sont principalement ou entierement d'origine humaine, alors que dans les effluents, ont une origine incertaine. Les parametres physico-chimiques ont pour la plupart des teneurs tres superieures aux normes indiquees par l'OMS. La normalisation a la croute continentale superieure revele des anomalies negatives sauf, dans le puits de Tergal ou le Ni presente une anomalie positive.
Download or read book Soil Conservation Service Curve Number SCS CN Methodology written by S.K. Mishra and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 535 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Soil Conservation Service (SCS) curve number (CN) method is one of the most popular methods for computing the runoff volume from a rainstorm. It is popular because it is simple, easy to understand and apply, and stable, and accounts for most of the runoff producing watershed characteristics, such as soil type, land use, hydrologic condition, and antecedent moisture condition. The SCS-CN method was originally developed for its use on small agricultural watersheds and has since been extended and applied to rural, forest and urban watersheds. Since the inception of the method, it has been applied to a wide range of environments. In recent years, the method has received much attention in the hydrologic literature. The SCS-CN method was first published in 1956 in Section-4 of the National Engineering Handbook of Soil Conservation Service (now called the Natural Resources Conservation Service), U. S. Department of Agriculture. The publication has since been revised several times. However, the contents of the methodology have been nonetheless more or less the same. Being an agency methodology, the method has not passed through the process of a peer review and is, in general, accepted in the form it exists. Despite several limitations of the method and even questionable credibility at times, it has been in continuous use for the simple reason that it works fairly well at the field level.
Download or read book MEGA CRISES written by Ira Helsloot and published by Charles C Thomas Publisher. This book was released on 2012-08-01 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: We live in turbulent times with continents and nations facing ever-heightening risks such as natural disasters, intense and protracted conflicts, terrorism, corporate crises, cyber threats to infrastructures and mega-events. We are witnessing the rise of mega-crises and a new class of adversity with many unknowns. The prospect of mega-crises presents professionals and students in the field of crisis management with four major tasks. First, they should engage in “deep thinking” about the causes of the increasing occurrence of mega-crises. Second, they should identify and work through the dominant trends which complicate contemporary crisis management. Third, they should upgrade institutional crisis management capacity. Fourth, they should improve societal resilience since no institutional complex can mitigate or manage these mega-crisis on its own. This book is divided into four primary parts, each of which looks at one facet of mega-crises. Part I focuses on the concept of a mega-crisis and mega-crisis management; Part II examines crisis management of mega-natural disasters; Part III evaluates crisis management of man-made mega-crises; and Part IV identifies mega-threats and vulnerabilities. Additional major topics include Hurricane Katrina; Hurricane Gustav; the London Bombings; the Mumbai Terrorist Attacks of July 7, 2005; corporate meltdowns; the subprime crisis; the Olympic Games; electricity grids; global climate change; the Dutch Delta; risks to food security; and mega-crises and the Internet. This comprehensive text will provide practitioners and academics with the results of an across-the-board research effort in the prospects, nature, characteristics, and the effects of mega-crises.
Download or read book Instructions and Tables for Computing Potential Evapotranspiration and the Water Balance written by Charles Warren Thornthwaite and published by . This book was released on 1957 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Instructions for evaluating the water balance; Tables for computing potential evapotranspiration and the water balance.
Download or read book Landscapes and Landforms of France written by Monique Fort and published by Springer Science & Business Media. This book was released on 2013-08-23 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Landforms and Landscapes of France provides an informative and attractive overview of the most scenic landscapes of France. The geodiversity of France is emphasized, for example the glacial landscapes of the Mont-Blanc Massif, the volcanoes of the French Massif Central, the chalk cliffs and sand dunes of the Atlantic coast, the granitic landscapes of Corsica or the lagoons and coral reefs of French Polynesia. The objectives are to provide the reader with an enjoyable and informative description of the selected sites within their regional geographical and geological settings; to offer an up-to-date survey of the evolution of France's landscape; and to give additional information on the cultural value of the selected sites wherever appropriate (prehistoric paintings, legends related to sites, famous vineyards, etc.). The book is a richly illustrated reference work that makes accessible for the first time a wealth of information currently scattered among many national and regional journals. It will be of benefit to earth scientists, environmental scientists, tourism geographers and conservationists
Download or read book Geosimulation written by Itzhak Benenson and published by John Wiley & Sons. This book was released on 2004-08-20 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geosimulation is hailed as ‘the next big thing’ in geographic modelling for urban studies. This book presents readers with an overview of this new and innovative field by introducing the spatial modelling environment and describing the latest research and development using cellular automata and multi-agent systems. Extensive case studies and working code is available from an associated website which demonstrate the technicalities of geosimulation, and provide readers with the tools to carry out their own modelling and testing. The first book to treat urban geosimulation explicitly, integrating socio-economic and environmental modelling approaches Provides the reader with a sound theoretical base in the science of geosimulation as well as applied material on the construction of geosimulation models Cross-references to an author-maintained associated website with downloadable working code for readers to apply the models presented in the book Visit the Author's Website for further information on Geosimulation, Geographic Automata Systems and Geographic Automata Software http://www.geosimulationbook.com
Download or read book Climate Change and Agriculture Worldwide written by Emmanuel Torquebiau and published by Springer. This book was released on 2015-10-26 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, especially with the approach of the 21st Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change in Paris in late 2015, the number of publications, conferences and meetings on climate change has been growing exponentially. Yet uncertainties remain concerning rural tropical areas where models are forecasting the onset of multiple disorders and trends are unclear. Meanwhile, the impact of climate change on the poorest communities is regularly documented, often prompting alarmist reactions. How can food security be achieved while adapting to and mitigating climate change? What are the main threats to agriculture in developing countries? How do farmers in these countries cope with the threats? What does agricultural research propose? What options have yet to be investigated? A broad scope of scientific research is underway to address these challenges. Diverse solutions are available, including new agricultural practices, water management, agricultural waste recycling, diagnosis of emerging diseases, payment for ecosystem services, etc. Gaining insight into the financial and political mechanisms that underlie international climate negotiations is also essential to design practical ways to deal with climate issues and meet sustainable development requirements in collaboration with farmers. This book pools the wealth of experience of dozens of researchers and development officers from a range of disciplines. We have focused on making it detailed, accurate and hopefully easy to read for researchers, students and all other informed readers.
Download or read book Groundwater Pollution in Africa written by Yongxin Xu and published by Taylor & Francis. This book was released on 2006-10-05 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2000, various UN organizations launched a collaborative effort to assess the vulnerability of groundwater in several African cities. The project addressed the issue of aquifer vulnerability and the protection of groundwater quality. This book is a collection of thirty peer-reviewed papers on the topic, and provides a glimpse of the situation acr
Download or read book Geomorphology and Global Environmental Change written by Olav Slaymaker and published by Cambridge University Press. This book was released on 2009-07-02 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: A statement from the world's leading geomorphologists on the state of, and potential changes to, the environment.
Download or read book MOUNTAIN GEOMORPHOLOGY written by Phil Owens and published by Routledge. This book was released on 2014-02-04 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mountains represent one of the most inspiring and attractive natural features on the surface of the earth. Visually, they dominate the landscape. However, the increasing realization of the fragility of mountain areas because of changes in land use, management and climate, combined with an understanding of their importance for water and other natural resources, has resulted in a growing interest in mountain environments in recent years. Hence, Mountain Geomorphology represents a timely and unique contribution to the literature. Written by a team of international experts, this book is divided into three sections, which consider historical, functional and applied mountain geomorphology from both global and local perspectives. Historical mountain geomorphology focuses on the evolution of landforms. Functional mountain geomorphology emphasises the interaction between processes and landforms, while applied mountain geomorphology concerns the interrelationships between geomorphological processes and society. Mountain Geomorphology is a valuable source of information for students studying mountain geomorphology, and also for academics and research scientists interested in mountain environments.
Download or read book Tropical Geomorphology written by Avijit Gupta and published by Cambridge University Press. This book was released on 2011-08-04 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although similar geomorphic processes take place in other regions, in the tropics these processes operate at different rates and with varying intensities. Tropical geomorphology therefore provides many new discoveries regarding geomorphic processes. This textbook describes both the humid and arid tropics. It provides thoroughly up-to-date concepts and relevant case studies, and emphasises the importance of geomorphology in the management and sustainable development of the tropical environment, including climate change scenarios. The text is supported by a large number of illustrations, including satellite images. Student exercises accompany each chapter. Tropical Geomorphology is an ideal textbook for any course on tropical geomorphology or the tropical environment, and is also invaluable as a reference text for researchers and environmental managers in the tropics.
Download or read book Water Saving in Agriculture written by and published by . This book was released on 2008 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mega geomorphology written by Rita Gardner and published by . This book was released on 1983 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geomorphic Hazards written by Olav Slaymaker and published by Chichester ; Toronto : Wiley. This book was released on 1996-06-12 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines geomorphic hazards, land form changes that adversely affect the geomorphic stability of a site or produces adverse socioeconomic impacts. These hazards include floods, landslides, seismicity, soil erosion and volcanic eruption.
