Floods in the Ganga–Brahmaputra–Meghna Delta

Foreword
Preface
Contents
Contributors
About the Editors
Chapter 1: Floods of Ganga-Brahmaputra-Meghna Delta in Context
1 Backdrop
2 The Ganga-Brahmaputra-Meghna Delta: A Geomorphic Unit
3 Living with Monsoon Floods
4 The Present Volume and Its Focus
5 Concluding Remarks
References
Chapter 2: Flood Inundation Modelling in Data-Sparse Flatlands: Challenges and Prospects
1 Flood as a Global Natural Hazard
2 The Issue of Limited Data in Flood-Prone Regions
2.1 Prevailing Mismatch in Scientific Advancement and Global Availability of Suitable Datasets
2.2 Applicability of SRTM DEMs for Flood Inundation Modelling
2.3 Applicability of Other Low-Cost Sources of DEMs in Inundation Modelling
2.4 Creating Accurate River Terrain Model from Sparse Data
3 Inundation Modelling at Regional and Reach Scales with Limited Data
4 Choice of the Model and the Required Level of Complexity
5 Treatment of Uncertainties
6 Conclusion
References
Chapter 3: Nature of Flood and Channel Sedimentation in the Torsa River: A Hydro-Geomorphic Study
1 Introduction
2 Study Area
3 Methodology
3.1 Data Used
3.2 Channel Hydrological Components
3.2.1 Flood Frequency
Gumbel´s Method
Log-Pearson Type III
Log Normal
3.2.2 Flash Flood Magnitude Index (FFMI)
3.3 Channel Morphology Parameters
3.3.1 Demarcation of Channel Reach
3.3.2 Measurements of Channel Bar Width and Channel Bar Area
3.3.3 Bed Elevation Change
4 Results and Discussion
4.1 Flood Discharge
4.2 Nature of Flood
4.3 Distribution of Peak Discharge
4.4 Simulation of the Flood Discharge
4.4.1 Goodness of Fit
4.5 Channel Morphology and Hydrological Control
4.6 Channel Bed Elevation and Discharge Characteristics
5 Conclusion
References
Chapter 4: Flood Risk Assessment of Himalayan Foothill Rivers: A Study of Jaldhaka River, India
1 Introduction
2 Study Area
3 Data Used and Methodology
3.1 Elevation
3.2 Slope
3.3 Rainfall
3.4 Distance from Rivers
3.5 Normalized Difference Vegetation Index (NDVI)
3.6 Bare Soil Index (BSI)
3.7 Topographic Wetness Index (TWI)
4 Results
4.1 Elevation
4.2 Slope
4.3 Rainfall (Cm)
5 Distance from Rivers (Meter)
6 Normalized Difference Vegetation Index (NDVI)
7 Bare Soil Index (BSI)
8 Topographic Wetness Index (TWI)
9 Flood Susceptibility Mapping
9.1 Validation
10 Discussion
11 Conclusion
References
Chapter 5: Flood Dynamics, River Erosion, and Vulnerability in the Catchment of Dharla and Dudhkumar Rivers in Bangladesh
1 Introduction
2 Materials and Methods
2.1 Study Area
2.2 Data Used and Methodology
3 Flood Dynamics: Nature and Magnitude
4 Causing of Floods
4.1 Natural Causes
4.2 Anthropogenic Causes
5 Impact of Floods
5.1 Impact on Hydro-Geomorphology
5.2 Impact on River Bank Erosion and Accretion
5.3 Impact on Resources, Live, and Livelihood
6 Flood Vulnerability
7 Management of Floods
7.1 Structural Approach
7.2 Nonstructural Approach
7.3 Coping Strategies, Policy Issues, and Local Level Implementation
8 Conclusions and Recommendations
References
Chapter 6: Assessing Human Control on Planform Modification over Floods: A Study of Lower Mahananda-Balason River System, India
1 Introduction
2 Database and Methodology
2.1 The Spatiotemporal Framework Selected for This Study
2.2 Dataset Procurement and Preprocessing
2.3 LULC Classification
2.4 Formulation and Measurement of the Indicators
2.5 Assessment of the Impact of Flood Discharge on Channel Planform
2.6 Estimating the Relationship Between the Anthropogenic Intervention and Planform Properties
3 Results
3.1 Spatiotemporal Dynamics of LULC
3.2 Measurement of the Indicators
3.3 Impact of Flood on Channel Modification
3.4 Relationship Between Human Interventions and Channel Planform
4 Discussions
4.1 Spatiotemporal Pattern of Anthropogenic Interventions and Planform Modification of MBS
4.2 Comparing the Role of Flood and Human Activities on Planform Modification
4.3 Possible Future Pattern of Channel Planform and Its Effects
5 Conclusion
Appendix
References
Chapter 7: Exploring the Flooding Under Damming Condition in Punarbhaba River of India and Bangladesh
1 Introduction
2 Study Area
3 Historical Perspective of Floods in the Punarbhaba River
4 Materials and Methods
4.1 Materials
4.2 Method for Flood Frequency and Magnitude Analysis
4.3 Instability of Flow
4.4 Methods for Regional Hydrologic Analysis
4.5 Method for Simulating Flooding
4.6 Method for Wetland Mapping
4.7 Method for Wetland Habitat Vulnerability Under Flooding Conditions Considering Damming Effect
4.8 Method for Flood Susceptibility Model
4.9 Method for Wetland Creation and Restoration Using Nature-Based Solution
5 Results and Discussion
5.1 Monitoring Flooding Conditions in the Punarbhaba River
5.2 Reconstruction of Flooding Under Damming Scenario
5.3 Impact of Flooding Under Dam Condition on Wetland Habitat Vulnerability
5.4 Drivers for Flooding
5.5 Recommendation for Flood and Floodplain Wetland Management
5.5.1 Flood Susceptibility Model
5.5.2 Wetland Conservation and Restoration Using Nature-Based Solution
6 Conclusion
References
Chapter 8: Morphometric Analysis and Prioritization of Watersheds for Flood Susceptibility Mapping in the Eastern Himalayan Fo...
1 Introduction
2 Study Area
2.1 Location of the Study Area
2.2 Flood Perspective of the Study Area
3 Data and Methods
4 Validation
5 Results and Discussion
5.1 Morphometric Parameters
5.1.1 Basic Parameters
5.1.2 Linear Parameters
5.1.3 Shape Parameters
5.1.4 Relief Parameters
5.2 Flood Prioritization of the Kaljani River Basin
6 Conclusions
References
Chapter 9: Application of Multi-Criteria Decision-Making Approach for Assessing Flood Susceptibility of the Tal-Diara and Bari...
1 Introduction
2 A Succinct Outline of the Research Area
3 Materials and Methods
3.1 Data Sources and Preparation of Thematic Layers
3.2 Factors that Affect Flood Conditions
3.2.1 Elevation (EL)
3.2.2 Distance from Major Rivers (DR)
3.2.3 Slope (SP)
3.2.4 Distance from River Confluence Point (DC)
3.2.5 Rainfall (RF)
3.2.6 Geomorphology (GM)
3.2.7 Soil (SL)
3.2.8 LULC
3.3 AHP Model for Flood Susceptibility Zones
3.4 Weighed Overlay Model (WOM)
3.5 Modeling Flood Susceptibility Zone
3.6 Validation of the Map of Flood Susceptibility
4 Results and Discussion
4.1 Location Factor
4.2 Breaching of Embankment
4.3 Inability of River Systems Vis-À-Vis Human Impact
5 Conclusion
References
Chapter 10: Agrarian and Socio-Infrastructural Vulnerability in the Wake of Flood: An Example from the Mayurakshi River Basin,...
1 Introduction
2 Study Area
3 Database and Methodology
3.1 Database
3.2 Methodology
3.2.1 Measuring Flood Hazard
3.2.2 Measuring Flood Vulnerability
3.2.3 Cropping Intensity and Diversification
3.2.4 Relative Importance Index
3.2.5 Student´s T-Test
4 Results and Discussion
4.1 Nature of Flood
4.2 Threat to the Agricultural Economy
4.3 Impact on House Condition
4.4 Impact on Road and Transport
4.5 Accessibility to Market
4.6 Health Problems
4.7 Education and Related Issues
4.8 Sociopsychological Problems
5 Conclusions
References
Chapter 11: Contemporary and Future Flood Characteristics and Associated Environmental Impact: A Study of Ajay River Basin, In...
1 Introduction
2 Geographical Set-up of the Study Area
3 Used Database and Methodology
4 Contemporary Flood Characteristics (1950s-2000s)
4.1 Trend in Flood Frequency During the Twentieth Century
4.2 Spatial Extension of Flood over the Lower ARB
4.3 Trend in Flood-Affected Area Since 1956
4.4 Dominant Impact on Agriculture
4.5 Effect on the Channel Geomorphology
5 Future Scenario of Flood Height and Affected Area (up to 2080)
6 Concluding Remarks
References
Chapter 12: Nature of Floods in the Khari River Basin, Eastern India
1 Introduction
2 Study Area
3 Database and Methodology
4 Result and Discussion
5 Conclusion
References
Chapter 13: Flood Risk Assessment and Numerical Modelling of Flood Simulation in the Damodar River Basin, Eastern India
1 Introduction
2 Geographical Settings of Study Area
3 Methodology
3.1 Data Collection
4 Methods
4.1 Basics of 1D-Hydrodyanmic Model
4.2 Steps in Flood Inundation Model of HEC-RAS
4.3 Risk and Flood Frequency Analysis
4.4 Other Hydrological Estimates
5 Results
5.1 Analysis of Flood Climate
5.2 Impact of Dam on Hydrological Variability
5.3 Flood Frequency and Hydrological Risk
5.4 1D Flood Simulation of Unsteady and Steady Flow
6 Discussion
7 Conclusion
References
Chapter 14: An Account of the Flood History in the Ghatal Region of West Bengal, India
1 Introduction
2 Locational Setting and Causes of Flood in the Ghatal Region
3 Disrupted Rivers and Embankments
4 Documenting the Near-Annual Flood Phenomenon in Ghatal
5 Conclusion
References
Chapter 15: A Baseline Study on Silaboti River Shifting, Flood, and Its Impact on Livelihood at Ghatal, Paschim Medinipur Dist...
1 Introduction
2 Materials and Methods
2.1 About Experiment Site
2.2 Database, Methodology, and Sampling
2.3 Cross Section
3 Results and Analysis
3.1 Shifting of River Course
3.2 Width-Depth Ratio
3.3 Meandering of a Stream
3.4 Catchment Size
3.5 Catchment Shape
3.6 Critical Drainage Pattern
4 Discussion
4.1 Effect on People
4.2 Effect on Agricultural Products
4.3 Road Damage
4.4 Effect on Household Damage
4.5 Effect on Health
4.6 Effect on Soil pH
5 Conclusion
References
Chapter 16: Future Floods in the Brahmaputra River Basin Based on Multi-model Ensemble of CMIP6 Projections
1 Introduction
2 Study Area
3 Data and Methods
4 Results and Discussion
4.1 Changes in Basin-Scale Precipitation
4.2 Tail Behavior of Extreme Precipitation Events
4.3 Future Peak Streamflow and River Stage
5 Conclusions
References
Chapter 17: Assessment of Flood Risk in the Brahmaputra-Jamuna Floodplain, Bangladesh
1 Introduction
2 Overview of the Study Area (Brahmaputra-Jamuna Floodplain)
3 Methods and Materials of the Study
3.1 Stages of Investigation
3.1.1 Collection and Analysis of Secondary Data
3.1.2 Questionnaire Survey and Field Observation
3.1.3 Preparation of Maps
3.1.4 Analysis of Findings Using Appropriate Statistical Techniques
4 Hazard Assessment (Hazard Index Identification)
4.1 General Hazard Index
5 Vulnerability Assessment
5.1 Analytical Model of Socioeconomic Vulnerability to Flood Risk
5.2 Coping Strategies: Adaptation and Mitigation
5.3 Local Knowledge System
5.4 Use of Indigenous Knowledge
6 Risk Assessment Through GIS-Based Model
6.1 Model Specification and Validation
6.2 Major Findings
6.3 Recommendations and Conclusions
References
Chapter 18: Characteristics of Flood in the Meghna River Basin Within Bangladesh
1 Introduction
2 Meghna River Course
3 Meghna River Catchment
4 Flood Characteristics of Meghna River
4.1 Meghna River Flood 2020
4.2 Meghna River Flood 2022
5 Floodplain Morphology
5.1 Sedimentation
5.2 Riverbank Erosion
6 Climate Change Impact
6.1 Hydrological Impact
6.2 Cyclonic Impact
7 Ecosystem Services of Meghna Floodplain
8 Floodplain Economy
9 Flood Management
10 Conclusions
References
Chapter 19: Flooding and Floodplain Management Around Dhaka City: A Case of Buriganga and Shitalakhya Rivers
1 Introduction
2 Study Area
3 Historical Perspective of Floods
4 Materials and Methods
5 Nature and Magnitude of Floods
6 Drivers and Causes of Floods
6.1 Natural Forces
6.2 Anthropogenic Factors
7 Impact of Floods on Physical Environment
8 Human Dimensions
8.1 Flood Vulnerabilities
8.2 Life and Livelihood
8.3 Coping Strategies
9 Management of Floods
9.1 Structural Measures
9.2 Nonstructural Measures
9.3 Policy Issues and Local-Level Implementation
10 Response to Floods
11 Conclusion and Way Forward
References
Chapter 20: Floods of Jalangi and Mathabhanga-Churni Rivers, Indo-Bangladesh
1 Introduction
2 Regional Settings
3 Historical Perspective
4 Materials and Methods
5 Nature and Magnitude of Floods
6 Drivers of Floods
6.1 Natural Forcing
6.1.1 Magnitude of Rainfall
6.1.2 Very Low Slope and Tortuous Course
6.1.3 Decayed Channel Retarding Hasty Pass of Floodwater
6.2 Anthropogenic Factors
6.2.1 Discharge from Reservoirs
6.2.2 Impact of Land Use and Land Cover (LULC)
6.3 Why Don´t Jalangi-Churni Flood as Before
6.3.1 Neotectonics and Deterioration of Distributaries
6.3.2 Delta-Forming Processes and River Shifting
6.3.3 Reduction in Rainfall
6.3.4 Reduced Flow of the Padma River
6.3.5 Farakka Barrage
7 Impact of Floods
7.1 Flood and Hydrogeomorphology
7.2 Flood and Floodplain Characteristics
7.3 Flood and Resource Appraisal
8 Management of Floods
8.1 Structural Approach (Hardware Solution)
8.2 Nonstructural Approach (Software Solution)
9 Response to Floods
9.1 Initiatives of the Communities, Government and NGOs
9.2 Way Forward
10 Conclusion
References
Chapter 21: Geospatial Assessment of Fluvial Dynamics and Associated Flood Vulnerability in the Bhagirathi-Hugli Sub-basin in ...
1 Introduction
2 Objectives
3 Materials and Methods
3.1 Study Area
3.2 Database
3.3 Delineation of Drainage Basins
3.4 DEM and Raster Analyses
3.5 Formulation of Composite Flood Vulnerability Index
3.6 Autocorrelation and Regression Analysis
4 Results and Discussions
4.1 Fluvial Dynamics and Characteristics of the Bhagirathi-Hugli River Basin
4.2 Factors of Flood Occurrences and Flood Vulnerability Index
4.3 Relationship Between NDFI and Its Predictors
4.4 Major Flood Incidence in 2015 and Outline of Flood Management
5 Conclusion
Appendices
Appendix A
Appendix B
References
Chapter 22: Floods of Gorai-Madhumati and Arial Khan Rivers, Bangladesh
1 Introduction
2 Study Area
3 Materials and Methods
4 The Changing Nature of the Delta over the Past Few Centuries
5 The Process of Delta Formation
6 Historical Perspective of Floods
7 Hydro-Morphological Characteristics of Gorai-Madhumati River
8 Hydro-Morphological Characteristics of Arial Khan River
9 Scenario of the Ganges Basin
9.1 The Gorai at Gorai Railway Bridge and Kamarkhali
9.2 The Arial Khan at Madaripur
10 Human Dimensions of Flooding in Bangladesh
11 Flood Vulnerabilities in Bangladesh
11.1 Economic Effects of Flooding
11.2 Effect on Personal Safety
11.3 Impacts of Flooding on Buildings and Infrastructures
11.4 Impacts of Flooding on Crops and Animals
12 Possible Solutions to the Issue of Flooding
12.1 Structural Solutions
12.2 Geologic Solutions
12.3 Dredging and Re-excavation
12.4 Prevention of Land Degradation
12.5 Flood Preparedness
12.6 Cooperation Within the Basin
13 Gorai River Restoration and Management
14 Arial Khan River Management
15 Conclusion
References
Index