Assessment of Causes and Impacts Of Flooding On Agricultural Production of Plains Surrounding Lake Tana, Ethiopia


Book Description

Master's Thesis from the year 2007 in the subject Agrarian Studies, grade: Very Good, , course: Irrigation Engineering, language: English, abstract: This study is an attempt to identify the main causes and effect of flooding on agricultural production and the peoples living in the Lake Tana surroundings. Although floods are relatively common during the June to September rainy season in Ethiopia, the magnitude of the current flooding in 2006 is unprecedented. In year 2006 the country has experienced some of the heaviest and most intense rains on record; resulting in flash floods and/or the overflow of rivers, lakes and dams, where local residents have been advised to leave. The impact of the disaster in terms of lives, infrastructure, livelihoods, and basic coping mechanisms has yet to be assessed The rainfall variability analysis of the Lake Tana (LT) basin in 2006 showed an on average 43% increase in wet season rainfall than the normal (mean). All rainfall gauging stations show an increase in rainfall in 2006. Similarly, the variability analysis of major rivers also showed that on average 35% increase in flood season streamflow of G/Abay, Gumara, Rib, Megech, and Koga. The trend of these rivers shows that maximum runoff for the year 2006 was higher than the mean of the long term maximum flood. Whereas Lake Tana maximum flood level of 2006 (1787.155masl) shows an increase of 16 cm only from the mean flood levels of previous records (1787 masl). The Pearson III method of the moment probability distribution is the best fit for Megech and Rib rivers. For Gumara river Pearson III probability weighted moment distribution better estimate flood quantiles with less standard error. It is also found that Gamma two probability weighted moment is the best fit for Lake Tana water surface level. In general, from rainfall and flood frequency analysis the 2006-year flooding may have a chance to occur once in six years in LTB. The 2006-year flood damage indicates that there is a high impact on agricultural production of Lake Tana surrounding plains. 107,647 peoples were actually affected by floods. At least 448, 910 quantal of food grain, 1230 domestic animals, 9634 chickens, and 1088 bee-hives were damaged by the 2006 flood. The impacts of flooding on socio-economic and environmental resource indicators were qualitatively assessed. Totally twenty-seven indicators were assessed.




Downstream Consequences of Ribb River Damming, Lake Tana Basin, Ethiopia


Book Description

This study assessed the downstream river system adaptation in response to upstream damming on the Ribb River, Ethiopia, to irrigate 15,000 ha. It combined primary and secondary data, and the application of remote sensing and mathematical modeling. The pre-dam morphodynamic trends of the Ribb River were analyzed for 59 years based on aerial photographs, satellite images, and newly collected field data. Three dam operation scenarios were developed to analyze the long-term hydro-morphological effects of the dam on the downstream river reaches. It also assessed the applicability of physics-based analytical equations (Equilibrium Theory) compared to a 1D numerical model (SOBEK-RE) to determine the least-morphologically impactful dam operation scenario on the river reaches downstream of the dam. Moreover, a HEC-RAS 2D hydrodynamic model was developed to assess the effect of the dam on the flooding extent of the Fogera Plain. This was used to study the potential implications of hydrological alteration on the ecology of the floodplain wetlands, as they are the habitats of important fish and bird species. The results contribute to knowledge on the hydro-morphological and environmental impacts of dams on downstream river systems. The developed methodologies and findings may be used to study future hydro-morphological and ecological changes that may arise due to other dam operations or climate change.




Extreme Hydrology and Climate Variability


Book Description

Extreme Hydrology and Climate Variability: Monitoring, Modelling, Adaptation and Mitigation is a compilation of contributions by experts from around the world who discuss extreme hydrology topics, from monitoring, to modeling and management. With extreme climatic and hydrologic events becoming so frequent, this book is a critical source, adding knowledge to the science of extreme hydrology. Topics covered include hydrometeorology monitoring, climate variability and trends, hydrological variability and trends, landscape dynamics, droughts, flood processes, and extreme events management, adaptation and mitigation. Each of the book's chapters provide background and theoretical foundations followed by approaches used and results of the applied studies. This book will be highly used by water resource managers and extreme event researchers who are interested in understanding the processes and teleconnectivity of large-scale climate dynamics and extreme events, predictability, simulation and intervention measures. - Presents datasets used and methods followed to support the findings included, allowing readers to follow these steps in their own research - Provides variable methodological approaches, thus giving the reader multiple hydrological modeling information to use in their work - Includes a variety of case studies, thus making the context of the book relatable to everyday working situations for those studying extreme hydrology - Discusses extreme event management, including adaption and mitigation




Spatial Modeling in GIS and R for Earth and Environmental Sciences


Book Description

Spatial Modeling in GIS and R for Earth and Environmental Sciences offers an integrated approach to spatial modelling using both GIS and R. Given the importance of Geographical Information Systems and geostatistics across a variety of applications in Earth and Environmental Science, a clear link between GIS and open source software is essential for the study of spatial objects or phenomena that occur in the real world and facilitate problem-solving. Organized into clear sections on applications and using case studies, the book helps researchers to more quickly understand GIS data and formulate more complex conclusions. The book is the first reference to provide methods and applications for combining the use of R and GIS in modeling spatial processes. It is an essential tool for students and researchers in earth and environmental science, especially those looking to better utilize GIS and spatial modeling. - Offers a clear, interdisciplinary guide to serve researchers in a variety of fields, including hazards, land surveying, remote sensing, cartography, geophysics, geology, natural resources, environment and geography - Provides an overview, methods and case studies for each application - Expresses concepts and methods at an appropriate level for both students and new users to learn by example




Social and Ecological System Dynamics


Book Description

This book is a social—ecological system description and feedback analysis of the Lake Tana Basin, the headwater catchment of the Upper Blue Nile River. This basin is an important local, national, and international resource, and concern about its sustainable development is growing at many levels. Lake Tana Basin outflows of water, sediments, nutrients, and contaminants affect water that flows downstream in the Blue Nile across international boundaries into the Nile River; the lake and surrounding land have recently been proposed as a UNESCO Biosphere Reserve; the basin has been designated as a key national economic growth corridor in the Ethiopian Growth and Transformation Plan. In spite of the Lake Tana Basin’s importance, there is no comprehensive, integrated, system-wide description of its characteristics and dynamics that can serve as a basis for its sustainable development. This book presents both the social and ecological characteristics of the region and an integrated, system-wide perspective of the feedback links that shape social and ecological change in the basin. Finally, it summarizes key research needs for sustainable development.




Wetlands of Ethiopia


Book Description




Evaluation of current and future water resources development in the Lake Tana Basin, Ethiopia


Book Description

Lake Tana, located in the headwaters of the Blue Nile, is valuable for many people including the communities who live around the lakeshore and those who live immediately downstream. The area has been identified as a region for hydropower and irrigation development, vital for economic growth in Ethiopia. A multidisciplinary study was conducted to assess the possible impacts of this development. This study found that current development has benefited some local people but adversely affected others. Future development will exacerbate pressure on the lake. Hard choices must be made about how the water is best utilized. It is important that all stakeholders, including local people, are involved in the decision-making process.




The Nile


Book Description

What have we learnt about the Nile since the mid-1970s, the moment when Julian Rzóska decided that the time had come to publish a comprehensive volume about the biology, and the geological and cultural history of that great river? And what changes have meanwhile occurred in the basin? The human popu- tion has more than doubled, especially in Egypt, but also in East Africa. Locally, industrial development has taken place, and the Aswan High Dam was clearly not the last major infrastructure work that was carried out. More dams have been built, and some water diversions, like the Toshka lakes, have created new expanses of water in the middle of the Sahara desert. What are the effects of all this on the ec- ogy and economy of the Basin? That is what the present book sets out to explore, 33 years after the publi- tion of “The Nile: Biology of an Ancient River”. Thirty-seven authors have taken up the challenge, and have written the “new” book. They come from 13 different countries, and 15 among them represent the largest Nilotic states (Egypt, Sudan, Ethiopia, Uganda, and Kenya). Julian Rzóska died in 1984, and most of the - authors of his book have now either disappeared or retired from research. Only Jack Talling and Samir Ghabbour were still available to participate again.




Cities and Flooding


Book Description

Urban flooding is an increasing challenge today to the expanding cities and towns of developing countries. This Handbook is a state-of-the art, user-friendly operational guide that shows decision makers and specialists how to effectively manage the risk of floods in rapidly urbanizing settings--and within the context of a changing climate.




River Basin Development and Human Rights in Eastern Africa — A Policy Crossroads


Book Description

This book is open access under a CC BY-NC 2.5 license. This book offers a devastating look at deeply flawed development processes driven by international finance, African governments and the global consulting industry. It examines major river basin development underway in the semi-arid borderlands of Ethiopia, Kenya and South Sudan and its disastrous human rights consequences for a half-million indigenous people. The volume traces the historical origins of Gibe III megadam construction along the Omo River in Ethiopia—in turn, enabling irrigation for commercial-scale agricultural development and causing radical reduction of downstream Omo and (Kenya's) Lake Turkana waters. Presenting case studies of indigenous Dasanech and northernmost Turkana livelihood systems and Gibe III linked impacts on them, the author predicts agropastoral and fishing economic collapse, region-wide hunger with exposure to disease epidemics, irreversible natural resource destruction and cross-border interethnic armed conflict spilling into South Sudan. The book identifies fundamental failings of government and development bank impact assessments, including their distortion or omission of mandated transboundary assessment, cumulative effects of the Gibe III dam and its linked Ethiopia-Kenya energy transmission 'highway' project, key hydrologic and human ecological characteristics, major earthquake threat in the dam region and widespread expropriation and political repression. Violations of internationally recognized human rights, especially by the Ethiopian government but also the Kenyan government, are extensive and on the increase—with collaboration by the development banks, in breach of their own internal operational procedures. A policy crossroads has now emerged. The author presents the alternative to the present looming catastrophe—consideration of development suspension in order to undertake genuinely independent transboundary assessment and a plan for continued development action within a human rights framework—forging a sustainable future for the indigenous peoples now directly threatened and for their respective eastern Africa states. Claudia Carr’s book is a treasure of detailed information gathered over many years concerning river basin development of the Omo River in Ethiopia and its impact on the peoples of the lower Omo Basin and the Lake Turkana region in Kenya. It contains numerous maps, charts, and photographs not previously available to the public. The book is highly critical of the environmental and human rights implications of the Omo River hydropower projects on both the local ethnic communities in Ethiopia and on the downstream Turkana in Kenya. David Shinn Former Ambassador to Ethiopia and to Burkina Faso Adjust Professor of International Affairs, The George Washington University, Washington D.C.