Bangladesh has predominantly four major river systems and Ganges river system is one of the large... more Bangladesh has predominantly four major river systems and Ganges river system is one of the largest and most important river systems of Bangladesh. The drainage basin is located mainly in the Southwest Region and the South-Central Region with small parts of the Northwest and North central Regions of Bangladesh. It is the main source of supply of water for people, agricultural, industry, conservation and for the delta system downstream. So, the surface water quality of Ganges basin holds the utmost importance for this region. The objective of this study is to assess the relation of surface water quality to hydrologic and climatic parameters by regression analysis and also to identify the sensitive water quality parameters that are most vulnerable to climatic and hydrologic change. Secondary time series data of climatic, hydrologic and surface water quality of the important rivers in the basin are used for this analysis. Secondary data of climatic and hydrological parameters included precipitation, evaporation, air temperatures, mean water level and discharge flow. Surface water quality parameters consisted of water temperature, total suspended solid (TSS), dissolved oxygen (DO), pH, electrical conductivity (EC), total alkalinity, chloride (Cl), iron (Fe) and biochemical oxygen demand (BOD). Arial Khan, Ganges, Mohananda, Dhepa, Tangon, Kobadak, Kumar, Gorai-Madhumati, Pagla are the major rivers for this study. The results show that precipitation has fair positive correlations with mean water level, discharge flow and air temperature and has weak negative correlation with evaporation. In case of surface water quality TSS and BOD both have weak to fair positive correlations with precipitation, discharge flow and water level. However, DO, pH, and alkalinity have observed negative correlations with all hydrological parameters. And finally, TSS, alkalinity, DO are proposed as sensitive water quality parameters in Ganges basin which are most influenced by hydrologic and climatic change.
Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development ... more Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development of this area for accommodation purpose has some adverse effect to the environment as well as the water logging problem. The elevation of the area is increased above the high flood level of the Old Brahmaputra river to overcome the flooding problem. Besides some new cannel are constructed which has divided the area into small parts. In this study the catchment of Mymensingh District is delineated using ArcSWAT, which is an extension of ArcGIS and the Peak Runoff of the sub-catchment is determined using the model SWMM. First runoff coefficients have been chosen for different sub-catchment areas. The design rainfall values have been evaluated using Gumbel's distribution for return period of 5 years and 10 years. The value of rainfall for 5 years and 10 years return periods are 226.6mm/day and 286.91mm/day respectively. The ranges of peak runoff, slope and runoff coefficient for different sub-catchments are between 3.18m3 /s to 1038m3/s, 0.01 to 0.04 and 0.295 to 0.705 respectively. It is observed that the model simulated value is close enough to the manually calculated value. The peak runoff obtained from the model simulation for high intensity of rainfall is less enough the drainage discharge capacity of the channels. However, during monsoon the HFL of the surrounding rivers may be higher than the water level of the drainage channels. To overcome this problem pump station can be introduced in each outlet. INTRODUCTION Mymensingh is located on the bank of the Brahmaputra river, but the urban areas are not usually affected by regular flooding except the extreme events such as the floods of 1988. An extensive network of internal channels and water bodies is linked to the external river system to which the stormwater and urban wastewater drain. The planned area has two parts-the built up urban areas, and the presently rural areas which will be developed under the plan in future. The urban areas are regularly affected by internal stormwater flooding primarily due to inadequate drainage infrastructure, and deficiency in maintenance and management of the drainage system. Growth of urban areas in Bangladesh has profound influence on the performance of urban drainage systems. Experiences in other major urban areas show that several factors determine the effectiveness and efficiency of the system. The main objectives of this study with regard to the study area are-i) to estimate the maximum runoff for different sub catchments ii) to design of the drainage network and iii) to assess the drainage operation during flood period.
Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development ... more Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development of this area for accommodation purpose has some adverse effect to the environment as well as the water logging problem. The elevation of the area is increased above the high flood level of the Old Brahmaputra river to overcome the flooding problem. Besides some new cannel are constructed which has divided the area into small parts. In this study the catchment of Mymensingh District is delineated using ArcSWAT, which is an extension of ArcGIS and the Peak Runoff of the sub-catchment is determined using the model SWMM. First runoff coefficients have been chosen for different sub-catchment areas. The design rainfall values have been evaluated using Gumbel's distribution for return period of 5 years and 10 years. The value of rainfall for 5 years and 10 years return periods are 226.6mm/day and 286.91mm/day respectively. The ranges of peak runoff, slope and runoff coefficient for different sub-catchments are between 3.18m3 /s to 1038m3/s, 0.01 to 0.04 and 0.295 to 0.705 respectively. It is observed that the model simulated value is close enough to the manually calculated value. The peak runoff obtained from the model simulation for high intensity of rainfall is less enough the drainage discharge capacity of the channels. However, during monsoon the HFL of the surrounding rivers may be higher than the water level of the drainage channels. To overcome this problem pump station can be introduced in each outlet. INTRODUCTION Mymensingh is located on the bank of the Brahmaputra river, but the urban areas are not usually affected by regular flooding except the extreme events such as the floods of 1988. An extensive network of internal channels and water bodies is linked to the external river system to which the stormwater and urban wastewater drain. The planned area has two parts-the built up urban areas, and the presently rural areas which will be developed under the plan in future. The urban areas are regularly affected by internal stormwater flooding primarily due to inadequate drainage infrastructure, and deficiency in maintenance and management of the drainage system. Growth of urban areas in Bangladesh has profound influence on the performance of urban drainage systems. Experiences in other major urban areas show that several factors determine the effectiveness and efficiency of the system. The main objectives of this study with regard to the study area are-i) to estimate the maximum runoff for different sub catchments ii) to design of the drainage network and iii) to assess the drainage operation during flood period.
Bangladesh has about a 710 km long coastline with the Bay of Bengal at the southernmost part of t... more Bangladesh has about a 710 km long coastline with the Bay of Bengal at the southernmost part of the country. Due to the dynamic characteristics of the Meghna estuary, geographic location and climatic conditions, the coastal regions of Bangladesh are subjected to a number of challenges every year including coastal erosion, sedimentation, salinity intrusion, tropical cyclone, storm surge, tidal bores etc. This study focuses on formulating a combination of protection and adaptation strategies to mitigate and counteract the current as well as future aggravated coastal challenges due to climate change impacts. The protection strategies include structural interventions such as coastal embankments, hydraulic structures such as regulators, sluice gates, breakwaters, afforestation and bank protection works and soft adaptation measures such as rainwater harvesting, cyclone shelters, etc. The effectiveness of the existing natural protection such as hilly elevated terrain in the southeast coast, mangrove forest in the west, natural forests in the islands at the estuary as well as of the artificial measures such as coastal polders, hydraulic structures, bank protection works, etc. are assessed in this context. The results of this study will be helpful for the policy makers to adopt suitable strategies to counteract the coastal hazards and thus reduce risk to human life, livelihood, agriculture, ecosystem and biodiversity.
Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges... more Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges and the Brahmaputra. These main rivers, their tributaries and distributaries control its hydrological and morphological behavior. The morphology of a river channel is a function of a number of processes and environmental conditions, including the composition and erodibility of the bed and banks (e.g., sand, clay, bedrock). This study analyzes the changing trends of hydrological and morphological parameters of Surma and Kushiyara river system. The field of research is focused on rive hydrology and river morphology.
Bangladesh is a country that encompasses many rivers in its small but quite diverse tract of land... more Bangladesh is a country that encompasses many rivers in its small but quite diverse tract of land. With around 230 rivers of 11739 km of length flowing through it, each river being different in characteristic and in many other ways, it can easily be understood that properly countering the problems posed by the rivers is a necessity. One of Bangladesh principal resources is its water which forms the basis for its transportation system and holds the key to agricultural development. Because of the almost flat surface of the country as well as the easy access of water, much of its economy is dependent on agriculture which basically depends on the river water to thrive. The economic growth and development of Bangladesh has been all highly influenced by water and its regional and seasonal availability and the quality of water. Water is an essence of life, providing sustenance and basis for all life force on earth. In Bangladesh, for irrigation and drinking purposes ground water had been used traditionally. Due to the depletion of ground water, surface water needs to be properly utilized. However, those which bring such a blessing for the country also rot destruction and bring about sufferings. So, implementation of proper management and river training scheme has become a crying necessity. The problems plaguing our rivers currently are: too much erosion-deposition, island and bar forming in the middle of the river, bed sedimentation, water logging, salinity, etc. It is easily understandable that to be able to tackle all of these problems, it is necessary to provide a system of check and balances within the river to get as much use out of river water as is possible for the betterment of the economy. The objective of the study is to assess the physical characteristics, resources, challenges and management of rivers of Bangladesh.
The coastal zone is the interface where the land meets the ocean, encompassing shoreline environm... more The coastal zone is the interface where the land meets the ocean, encompassing shoreline environments as well as adjacent coastal waters. The high concentration of people in coastal regions has produced many economic benefits. The objective of the study is to assess the physical characteristics, resources, challenges and management of coastal zone of Bangladesh. Bangladesh is a low-lying country faced many coastal problems such as storm surge, flood, tsunami, sea level rise, erosion and proper managements are taken to solve this problem.
The coastal zone is the interface where the land meets the ocean, encompassing shoreline environm... more The coastal zone is the interface where the land meets the ocean, encompassing shoreline environments as well as adjacent coastal waters. The high concentration of people in coastal regions has produced many economic benefits. In view of the coastal areas, vulnerability to natural hazards particularly tsunami, storm surge, erosion, salinity intrusion, sea level rise are increasing now a days. Various protection and management measures are carried out against those natural hazards. It is important to explore all the various coastal threats so that coastal managers can take proper mitigation measures. This study is focused on the major challenges and vulnerabilities at some coasts of the world, such as Japan, Netherlands, Vietnam, Srilanka and Bangladesh which are greatly affected by the tsunami, storm surge, erosion, cyclone, salinity etc. Management activities to mitigate the challenges by the coastal authorities of those countries have also been investigated. Details of challenges and management of Bangladesh coastal zone have been assessed. Finally some recommendations have been made of the management of the Bangladesh coastal zone.
Bangladesh is a flood prone country situated on the Ganges Delta and the many distributaries flow... more Bangladesh is a flood prone country situated on the Ganges Delta and the many distributaries flowing into the Bay of Bengal and its lower elevation. Bangladesh is situated in the lowest area of the Hindu Kush-Himalayan Region (HKH) and is famous as one of the highest flood prone countries in the world. About 700 rivers including tributaries flow through the country constituting a waterway of total length around 24,140 kilometers. Flood causes tremendous losses in terms of property and life, particularly in the low land areas. At least 20 % areas are flooded every year and in case of severe flood, about three fourth part of the country is inundated. The Surma and Kushiyara river system is major river system in Bangladesh, part of the Surma-Meghna River System and situated in the Sylhet basin. So flooding of the sylhet basin is frequent because of the river system. It starts when the Barak River from NorthEast India divides at the Bangladesh border into the Surma and the Kushiyara rivers. The study is carried out to develop inundation maps of the Surma and the Kushiyara River. The study made here is based upon a combined one and two dimensional HEC-RAS model. This model needs cooperation of GIS and HEC-GeoRAS. The later twos help to produce appropriate river reaches for Surma and Kusiyara. In HEC-RAS 1D and 2D, boundary conditions for upstream and downstream are defined by discharge and water level for running the 1D and 2D river. After boundary condition setup, the channel calibration and validation are performed using known hydrological data collected from Bangladesh Water Development Board. However, calibration and validation showed result much closer to the actual scenario. After calibration and validation flood inundation map are generated using RAS Mapper. Changing the actual discharge different scenario are generated using RAS Mapper. Those scenarios are calculated in GIS by exporting data from HECRAS to GIS. Levee is constructed in HECRAS 2D. The average levee height was about 1.8 m which showed significant amount of resistance against flood. Later, the analysis of flood pattern helped to understand the seasonal growth of flood. Thus, ending of the study may help in planning and management of flood plain area of the Surma and Kusiyara Rivers to mitigate future probable disaster through technical approach. Findings of the study may also help to determine suitability of building flood control structure like embankment, detention ponds for prevention purposes.
Bangladesh, is house to myriad of rivers in its very compact space of only around 1, 47,570 sq. k... more Bangladesh, is house to myriad of rivers in its very compact space of only around 1, 47,570 sq. kms. From the Himalayan mountains flowing through India and entering Bangladesh through the Nilphamari district, the river Teesta is considered the very life giver for the people living in the Northern region of Bangladesh. Over the course of history this river has seen many changes in its flow path mainly due to flooding as well as tectonic plate shifting in the form of earthquake and geographical structural changes. Today the river is basically the accumulated flow of three rivers. At present this river however, is prone to changes in the form of constant erosion and deposition. The river bank sees more erosion than deposition in the present years; the river has experienced a high amount of erosion leading to the disruption of life of people along the river. In this paper, this erosion as well as deposition rate or in other words, the plan form analysis of the river has been shown. An analysis of 27 years has been presented in the study from 1990-2017. This analysis has been done with the help of images generated from USGS and later from these images after generating the necessary shape files with the help of ArcGIS software, the erosion and deposition along the river bank was quantified by using MS Excel software. From the analysis, it was seen that the rate of erosion is higher than the deposition. The river experiences high level of flow during the wet season leading to more erosion. INTRODUCTION The country Bangladesh is occupied with a network of about 405 rivers mostly alluvial in nature, spreading all over the country out of which 57 are transboundary (BWDB, 2011). Teesta River, is a trans boundary river shared by India and Bangladesh. Bangladesh being the lowermost riparian country, the water of the river is very vital for the sustenance of livelihood, planning of new water resources projects including evaluation of existing projects and optimum usage of natural resources. Riverbank erosion is one of the most unpredictable and critical disaster that takes into account the quantity of rainfall, soil structure, river morphology, topography of river and adjacent areas and effect of floods.
Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges... more Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges and the Brahmaputra. These main rivers, their tributaries and distributaries control its hydrological and morphological behavior. The morphology of a river channel is a function of a number of processes and environmental conditions, including the composition and erosion possibility of the bed and banks (e.g., sand, clay, bedrock).This study analyzes the changing trends of hydrological and morphological parameters of Surma and Kushiyara river system. The field of research is focused on rive hydrology and river morphology.
Bangladesh has predominantly four major river systems and Ganges river system is one of the large... more Bangladesh has predominantly four major river systems and Ganges river system is one of the largest and most important river systems of Bangladesh. The drainage basin is located mainly in the Southwest Region and the South-Central Region with small parts of the Northwest and North central Regions of Bangladesh. It is the main source of supply of water for people, agricultural, industry, conservation and for the delta system downstream. So, the surface water quality of Ganges basin holds the utmost importance for this region. The objective of this study is to assess the relation of surface water quality to hydrologic and climatic parameters by regression analysis and also to identify the sensitive water quality parameters that are most vulnerable to climatic and hydrologic change. Secondary time series data of climatic, hydrologic and surface water quality of the important rivers in the basin are used for this analysis. Secondary data of climatic and hydrological parameters included precipitation, evaporation, air temperatures, mean water level and discharge flow. Surface water quality parameters consisted of water temperature, total suspended solid (TSS), dissolved oxygen (DO), pH, electrical conductivity (EC), total alkalinity, chloride (Cl), iron (Fe) and biochemical oxygen demand (BOD). Arial Khan, Ganges, Mohananda, Dhepa, Tangon, Kobadak, Kumar, Gorai-Madhumati, Pagla are the major rivers for this study. The results show that precipitation has fair positive correlations with mean water level, discharge flow and air temperature and has weak negative correlation with evaporation. In case of surface water quality TSS and BOD both have weak to fair positive correlations with precipitation, discharge flow and water level. However, DO, pH, and alkalinity have observed negative correlations with all hydrological parameters. And finally, TSS, alkalinity, DO are proposed as sensitive water quality parameters in Ganges basin which are most influenced by hydrologic and climatic change.
Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development ... more Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development of this area for accommodation purpose has some adverse effect to the environment as well as the water logging problem. The elevation of the area is increased above the high flood level of the Old Brahmaputra river to overcome the flooding problem. Besides some new cannel are constructed which has divided the area into small parts. In this study the catchment of Mymensingh District is delineated using ArcSWAT, which is an extension of ArcGIS and the Peak Runoff of the sub-catchment is determined using the model SWMM. First runoff coefficients have been chosen for different sub-catchment areas. The design rainfall values have been evaluated using Gumbel's distribution for return period of 5 years and 10 years. The value of rainfall for 5 years and 10 years return periods are 226.6mm/day and 286.91mm/day respectively. The ranges of peak runoff, slope and runoff coefficient for different sub-catchments are between 3.18m3 /s to 1038m3/s, 0.01 to 0.04 and 0.295 to 0.705 respectively. It is observed that the model simulated value is close enough to the manually calculated value. The peak runoff obtained from the model simulation for high intensity of rainfall is less enough the drainage discharge capacity of the channels. However, during monsoon the HFL of the surrounding rivers may be higher than the water level of the drainage channels. To overcome this problem pump station can be introduced in each outlet. INTRODUCTION Mymensingh is located on the bank of the Brahmaputra river, but the urban areas are not usually affected by regular flooding except the extreme events such as the floods of 1988. An extensive network of internal channels and water bodies is linked to the external river system to which the stormwater and urban wastewater drain. The planned area has two parts-the built up urban areas, and the presently rural areas which will be developed under the plan in future. The urban areas are regularly affected by internal stormwater flooding primarily due to inadequate drainage infrastructure, and deficiency in maintenance and management of the drainage system. Growth of urban areas in Bangladesh has profound influence on the performance of urban drainage systems. Experiences in other major urban areas show that several factors determine the effectiveness and efficiency of the system. The main objectives of this study with regard to the study area are-i) to estimate the maximum runoff for different sub catchments ii) to design of the drainage network and iii) to assess the drainage operation during flood period.
Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development ... more Mymensingh District situated in flood plain between Old Brahmaputra and Banar river. Development of this area for accommodation purpose has some adverse effect to the environment as well as the water logging problem. The elevation of the area is increased above the high flood level of the Old Brahmaputra river to overcome the flooding problem. Besides some new cannel are constructed which has divided the area into small parts. In this study the catchment of Mymensingh District is delineated using ArcSWAT, which is an extension of ArcGIS and the Peak Runoff of the sub-catchment is determined using the model SWMM. First runoff coefficients have been chosen for different sub-catchment areas. The design rainfall values have been evaluated using Gumbel's distribution for return period of 5 years and 10 years. The value of rainfall for 5 years and 10 years return periods are 226.6mm/day and 286.91mm/day respectively. The ranges of peak runoff, slope and runoff coefficient for different sub-catchments are between 3.18m3 /s to 1038m3/s, 0.01 to 0.04 and 0.295 to 0.705 respectively. It is observed that the model simulated value is close enough to the manually calculated value. The peak runoff obtained from the model simulation for high intensity of rainfall is less enough the drainage discharge capacity of the channels. However, during monsoon the HFL of the surrounding rivers may be higher than the water level of the drainage channels. To overcome this problem pump station can be introduced in each outlet. INTRODUCTION Mymensingh is located on the bank of the Brahmaputra river, but the urban areas are not usually affected by regular flooding except the extreme events such as the floods of 1988. An extensive network of internal channels and water bodies is linked to the external river system to which the stormwater and urban wastewater drain. The planned area has two parts-the built up urban areas, and the presently rural areas which will be developed under the plan in future. The urban areas are regularly affected by internal stormwater flooding primarily due to inadequate drainage infrastructure, and deficiency in maintenance and management of the drainage system. Growth of urban areas in Bangladesh has profound influence on the performance of urban drainage systems. Experiences in other major urban areas show that several factors determine the effectiveness and efficiency of the system. The main objectives of this study with regard to the study area are-i) to estimate the maximum runoff for different sub catchments ii) to design of the drainage network and iii) to assess the drainage operation during flood period.
Bangladesh has about a 710 km long coastline with the Bay of Bengal at the southernmost part of t... more Bangladesh has about a 710 km long coastline with the Bay of Bengal at the southernmost part of the country. Due to the dynamic characteristics of the Meghna estuary, geographic location and climatic conditions, the coastal regions of Bangladesh are subjected to a number of challenges every year including coastal erosion, sedimentation, salinity intrusion, tropical cyclone, storm surge, tidal bores etc. This study focuses on formulating a combination of protection and adaptation strategies to mitigate and counteract the current as well as future aggravated coastal challenges due to climate change impacts. The protection strategies include structural interventions such as coastal embankments, hydraulic structures such as regulators, sluice gates, breakwaters, afforestation and bank protection works and soft adaptation measures such as rainwater harvesting, cyclone shelters, etc. The effectiveness of the existing natural protection such as hilly elevated terrain in the southeast coast, mangrove forest in the west, natural forests in the islands at the estuary as well as of the artificial measures such as coastal polders, hydraulic structures, bank protection works, etc. are assessed in this context. The results of this study will be helpful for the policy makers to adopt suitable strategies to counteract the coastal hazards and thus reduce risk to human life, livelihood, agriculture, ecosystem and biodiversity.
Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges... more Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges and the Brahmaputra. These main rivers, their tributaries and distributaries control its hydrological and morphological behavior. The morphology of a river channel is a function of a number of processes and environmental conditions, including the composition and erodibility of the bed and banks (e.g., sand, clay, bedrock). This study analyzes the changing trends of hydrological and morphological parameters of Surma and Kushiyara river system. The field of research is focused on rive hydrology and river morphology.
Bangladesh is a country that encompasses many rivers in its small but quite diverse tract of land... more Bangladesh is a country that encompasses many rivers in its small but quite diverse tract of land. With around 230 rivers of 11739 km of length flowing through it, each river being different in characteristic and in many other ways, it can easily be understood that properly countering the problems posed by the rivers is a necessity. One of Bangladesh principal resources is its water which forms the basis for its transportation system and holds the key to agricultural development. Because of the almost flat surface of the country as well as the easy access of water, much of its economy is dependent on agriculture which basically depends on the river water to thrive. The economic growth and development of Bangladesh has been all highly influenced by water and its regional and seasonal availability and the quality of water. Water is an essence of life, providing sustenance and basis for all life force on earth. In Bangladesh, for irrigation and drinking purposes ground water had been used traditionally. Due to the depletion of ground water, surface water needs to be properly utilized. However, those which bring such a blessing for the country also rot destruction and bring about sufferings. So, implementation of proper management and river training scheme has become a crying necessity. The problems plaguing our rivers currently are: too much erosion-deposition, island and bar forming in the middle of the river, bed sedimentation, water logging, salinity, etc. It is easily understandable that to be able to tackle all of these problems, it is necessary to provide a system of check and balances within the river to get as much use out of river water as is possible for the betterment of the economy. The objective of the study is to assess the physical characteristics, resources, challenges and management of rivers of Bangladesh.
The coastal zone is the interface where the land meets the ocean, encompassing shoreline environm... more The coastal zone is the interface where the land meets the ocean, encompassing shoreline environments as well as adjacent coastal waters. The high concentration of people in coastal regions has produced many economic benefits. The objective of the study is to assess the physical characteristics, resources, challenges and management of coastal zone of Bangladesh. Bangladesh is a low-lying country faced many coastal problems such as storm surge, flood, tsunami, sea level rise, erosion and proper managements are taken to solve this problem.
The coastal zone is the interface where the land meets the ocean, encompassing shoreline environm... more The coastal zone is the interface where the land meets the ocean, encompassing shoreline environments as well as adjacent coastal waters. The high concentration of people in coastal regions has produced many economic benefits. In view of the coastal areas, vulnerability to natural hazards particularly tsunami, storm surge, erosion, salinity intrusion, sea level rise are increasing now a days. Various protection and management measures are carried out against those natural hazards. It is important to explore all the various coastal threats so that coastal managers can take proper mitigation measures. This study is focused on the major challenges and vulnerabilities at some coasts of the world, such as Japan, Netherlands, Vietnam, Srilanka and Bangladesh which are greatly affected by the tsunami, storm surge, erosion, cyclone, salinity etc. Management activities to mitigate the challenges by the coastal authorities of those countries have also been investigated. Details of challenges and management of Bangladesh coastal zone have been assessed. Finally some recommendations have been made of the management of the Bangladesh coastal zone.
Bangladesh is a flood prone country situated on the Ganges Delta and the many distributaries flow... more Bangladesh is a flood prone country situated on the Ganges Delta and the many distributaries flowing into the Bay of Bengal and its lower elevation. Bangladesh is situated in the lowest area of the Hindu Kush-Himalayan Region (HKH) and is famous as one of the highest flood prone countries in the world. About 700 rivers including tributaries flow through the country constituting a waterway of total length around 24,140 kilometers. Flood causes tremendous losses in terms of property and life, particularly in the low land areas. At least 20 % areas are flooded every year and in case of severe flood, about three fourth part of the country is inundated. The Surma and Kushiyara river system is major river system in Bangladesh, part of the Surma-Meghna River System and situated in the Sylhet basin. So flooding of the sylhet basin is frequent because of the river system. It starts when the Barak River from NorthEast India divides at the Bangladesh border into the Surma and the Kushiyara rivers. The study is carried out to develop inundation maps of the Surma and the Kushiyara River. The study made here is based upon a combined one and two dimensional HEC-RAS model. This model needs cooperation of GIS and HEC-GeoRAS. The later twos help to produce appropriate river reaches for Surma and Kusiyara. In HEC-RAS 1D and 2D, boundary conditions for upstream and downstream are defined by discharge and water level for running the 1D and 2D river. After boundary condition setup, the channel calibration and validation are performed using known hydrological data collected from Bangladesh Water Development Board. However, calibration and validation showed result much closer to the actual scenario. After calibration and validation flood inundation map are generated using RAS Mapper. Changing the actual discharge different scenario are generated using RAS Mapper. Those scenarios are calculated in GIS by exporting data from HECRAS to GIS. Levee is constructed in HECRAS 2D. The average levee height was about 1.8 m which showed significant amount of resistance against flood. Later, the analysis of flood pattern helped to understand the seasonal growth of flood. Thus, ending of the study may help in planning and management of flood plain area of the Surma and Kusiyara Rivers to mitigate future probable disaster through technical approach. Findings of the study may also help to determine suitability of building flood control structure like embankment, detention ponds for prevention purposes.
Bangladesh, is house to myriad of rivers in its very compact space of only around 1, 47,570 sq. k... more Bangladesh, is house to myriad of rivers in its very compact space of only around 1, 47,570 sq. kms. From the Himalayan mountains flowing through India and entering Bangladesh through the Nilphamari district, the river Teesta is considered the very life giver for the people living in the Northern region of Bangladesh. Over the course of history this river has seen many changes in its flow path mainly due to flooding as well as tectonic plate shifting in the form of earthquake and geographical structural changes. Today the river is basically the accumulated flow of three rivers. At present this river however, is prone to changes in the form of constant erosion and deposition. The river bank sees more erosion than deposition in the present years; the river has experienced a high amount of erosion leading to the disruption of life of people along the river. In this paper, this erosion as well as deposition rate or in other words, the plan form analysis of the river has been shown. An analysis of 27 years has been presented in the study from 1990-2017. This analysis has been done with the help of images generated from USGS and later from these images after generating the necessary shape files with the help of ArcGIS software, the erosion and deposition along the river bank was quantified by using MS Excel software. From the analysis, it was seen that the rate of erosion is higher than the deposition. The river experiences high level of flow during the wet season leading to more erosion. INTRODUCTION The country Bangladesh is occupied with a network of about 405 rivers mostly alluvial in nature, spreading all over the country out of which 57 are transboundary (BWDB, 2011). Teesta River, is a trans boundary river shared by India and Bangladesh. Bangladesh being the lowermost riparian country, the water of the river is very vital for the sustenance of livelihood, planning of new water resources projects including evaluation of existing projects and optimum usage of natural resources. Riverbank erosion is one of the most unpredictable and critical disaster that takes into account the quantity of rainfall, soil structure, river morphology, topography of river and adjacent areas and effect of floods.
Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges... more Bangladesh stands on a thick alluvial deposit. It is the result of deltaic activity of the Ganges and the Brahmaputra. These main rivers, their tributaries and distributaries control its hydrological and morphological behavior. The morphology of a river channel is a function of a number of processes and environmental conditions, including the composition and erosion possibility of the bed and banks (e.g., sand, clay, bedrock).This study analyzes the changing trends of hydrological and morphological parameters of Surma and Kushiyara river system. The field of research is focused on rive hydrology and river morphology.
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