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

Master's Thesis , 2007 , 165 Pages , Grade: Very Good

Agrarian Studies

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.

Inhaltsverzeichnis (Table of Contents)

• CHAPTER ONE
  • 1 INTRODUCTION
    • 1.1 GENERAL
    • 1.2 STATEMENT OF THE PROBLEM
    • 1.3 OBJECTIVE AND SCOPE OF THE STUDY
• CHAPTER TWO
  • 2 LITERATURE REVIEW
    • 2.1 FLOOD DISASTER AND ITS IMPACTS
    • 2.2 PLANT RESPONSE TO FLOODING
    • 2.3 FLOODPLAIN MANAGEMENT
    • 2.4 IMPACTS OF FLOOD CONTROL AND PREVENTION MEASURES
    • 2.5 INTEGRATED FLOOD MANAGEMENT
      • 2.5.1 Elements of Integrated Flood Management
    • 2.6 WATERLOGGING AND DEVELOPMENT OF HIGH WATER TABLE
      • 2.6.1 Signs of Bad Drainage
      • 2.6.2 Harmful Effects of Excess Irrigation
      • 2.6.3 Benefits of drainage
      • 2.6.4 Biodrainage
• CHAPTER THREE
  • 3 DESCRIPTION AND METHDOLOGY
    • 3.1 DESCRIPTION OF THE STUDY AREA
      • 3.1.1 Administrative Location
      • 3.1.2 Geographical Location
    • 3.2 METHODOLOGY
      • 3.2.1 Data Collection
      • 3.2.2 Data Processing
    • 3.3 BASIC FEATURES OF THE STUDY AREAS
      • 3.3.1 Agro ecological Zones
      • 3.3.2 Geology of Lake Tana Plains
      • 3.3.3 Drainage
      • 3.3.4 Soils of Lake Tana Surrounding Plains
      • 3.3.5 Topography
      • 3.3.6 Land Use
      • 3.3.7 Socio-economy
• CHAPTER FOUR
  • 4 DATA ANALYSIS AND RESULTS
    • 4.1 FLOOD ASSESSMENT BASED ON VARIABILITY OF RAINFALL AND STREAM FLOW DATA
      • 4.1.1 Rainfall Variability
      • 4.1.2 Stream Flow Variability
      • 4.1.3 Lake Tana Water Level Variation and Flood Recession
    • 4.2 HYDROLOGIC FREQUENCY ANALYSIS
      • 4.2.1 Flood Frequency Analysis
      • 4.2.2 Frequency Analysis of Rainfall
    • 4.3 SOCIO ECONOMIC IMPACT OF FLOODING ON LTSPS
      • 4.3.1 Nature of Flooding on LTSPS
      • 4.3.2 Flood Affected Areas
      • 4.3.3 Causes of Flooding and Waterlogging in LTSPs
      • 4.3.4 The Impact Flooding on Agricultural Production of LTSPS
    • 4.4 POTENTIAL MITIGATION MEASURES
      • 4.4.1 Flood Management Options
      • 4.4.2 Agricultural Drainage options
• CHAPTER FIVE
  • 5 DISCUSSION OF RESULTS
    • 5.1 RESULTS OF THE VARIABILITY ANALYSIS OF RAINFALL AND RUNOFF
    • 5.2 RESULT OF HYDROLOGICAL FREQUENCY ANALYSIS
    • 5.3 RESULT OF SOCIO ECONOMIC IMPACT ASSESSMENT OF FLOODING ON AGRICULTURAL PRODUCTION OF LTSPS
    • 5.4 RESULTS OF THE POTENTIAL MITIGATION MEASURES FOR FLOODING AND DRAINAGE PROBLEMS
• CHAPTER SIX
  • 6 SUMMERY, CONCLUSION AND RECOMMENDATION
    • 6.1 SUMMERY AND CONCLUSION
    • 6.2 RECOMMENDATIONS
    • 6.3 LIMITATIONS

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This research aims to assess the causes and impacts of flooding on agricultural production in the Lake Tana surrounding plains. The study explores the patterns of rainfall, stream flow, and lake water level fluctuations to understand the dynamics of flooding in the region. Furthermore, it investigates the socio-economic impacts of flooding on the agricultural practices and livelihoods of the local communities.

• Assessment of the causes and impacts of flooding on agricultural production in the Lake Tana surrounding plains.
• Analysis of rainfall, stream flow, and lake water level variations to understand the dynamics of flooding.
• Evaluation of the socio-economic impacts of flooding on the agricultural practices and livelihoods of the local communities.
• Identification of potential mitigation measures for flood control and drainage problems.
• Development of recommendations for sustainable agricultural practices and flood management strategies.

Zusammenfassung der Kapitel (Chapter Summaries)

Chapter One provides an introduction to the research topic, outlining the problem statement and objectives. It establishes the context for the study and highlights the importance of understanding flooding impacts on agricultural production in the Lake Tana surrounding plains. Chapter Two presents a comprehensive literature review, exploring existing research on flood disasters, their impacts on agricultural production, and related mitigation strategies. It delves into various aspects of flood management, including integrated flood management, waterlogging, and drainage techniques. Chapter Three focuses on the methodology employed in the study, including the description of the study area, data collection techniques, and data processing methods. It provides details on the geographical and administrative context, as well as the key features of the study area such as agro-ecological zones, geology, drainage, soils, topography, land use, and socio-economic characteristics. Chapter Four presents the data analysis and results, examining the variability of rainfall, stream flow, and lake water levels. It also analyzes the socio-economic impacts of flooding on the local communities, including the nature of flooding, affected areas, causes, and impacts on agricultural production. This chapter further explores potential mitigation measures for flood control and drainage problems. Chapter Five discusses the findings and interprets the results presented in Chapter Four. It provides a deeper understanding of the complex interplay between flooding, agricultural practices, and socio-economic factors in the Lake Tana surrounding plains. Chapter Six summarizes the research findings, draws conclusions based on the data analysis, and presents recommendations for future actions. It emphasizes the need for sustainable flood management strategies and highlights the importance of community involvement in mitigating the impacts of flooding.

Schlüsselwörter (Keywords)

The key focus of this study lies in understanding the interplay of flooding, agricultural production, and socio-economic factors in the Lake Tana surrounding plains. It investigates rainfall and runoff variability, hydrological frequency analysis, the socio-economic impact assessment of flooding, and explores potential mitigation measures for flood control and drainage problems. Key terms and concepts include flooding, agricultural production, Lake Tana, rainfall variability, stream flow, water level fluctuations, socio-economic impacts, flood management, drainage, mitigation measures, and sustainable agricultural practices.

• Course: Irrigation Engineering
• Grade: Very Good
• Author: Yirga Alemu Azene (Author)
• Publication Year: 2007
• Pages: 165
• Catalog Number: V945382
• ISBN (eBook): 9783346304674
• ISBN (Book): 9783346304681
• Language: English
• Tags: Lake Tana, Flooding, Flood control, Disaster, Environmental Assessment