River dynamics play the most vital role in the socio-economic of the country. These rivers are highly dynamic in nature which causes extensive riverbank erosion. Active river bank erosion and bed scouring, is apprehen...River dynamics play the most vital role in the socio-economic of the country. These rivers are highly dynamic in nature which causes extensive riverbank erosion. Active river bank erosion and bed scouring, is apprehended to change the scenario, leading to loss of limited valuable land of Bangladesh. River training is being practiced in Bangladesh since 1960s but the process is very expensive especially in the Ganges and the Jamuna Rivers. Five types of river training works were selected at different reaches. Hydro-morphological characteristics of the major rivers are being evaluated not only in engineering concepts but also in socio-economic and environmental aspects. PRA （participatory rural appraisal） tools were applied to evaluate protection safety, hydraulic and hydrological connectivity, ecological and environmental characteristics, causes of failure and social acceptability. This comparative study is being carried out for closing the gap between the modem river training works and in country experience through adaptation of research findings with a view to effectively arresting river bank erosion. Sirajganj Hardpoint, Chandpur Town Protection work and Nakalia Revetment are found to be suitable and effective. A technically suitable structure may not have good social acceptance without IWRM （integrated water resource management）.展开更多
The Payra is a tidal river with meandering planform in which around 6.5 km long landmass is formed naturally during the last 40 years that is selected for an establishment by the Government of Bangladesh. However, the...The Payra is a tidal river with meandering planform in which around 6.5 km long landmass is formed naturally during the last 40 years that is selected for an establishment by the Government of Bangladesh. However, the site experiences intermittent erosion at several locations and poses threat to the newly developed infrastructures. In the present study, a Rouse type simple model is used to estimate the equilibrium profiles of suspended sediment concentration below which the system is likely to be eroded and regarded as “Sediment Deficit System, SDS” and above which the system is likely to be sedimented and regarded as “Sediment Surplus System, SSS”. The model was then tested at the study reach using the measured flow-sediment data complemented by field observation and Landsat images-based planform analysis. The analysis revealed that the residual flow-sediment regime in the study site is representing the “sediment deficit system” that causes continuous threat for erosion throughout the tidal cycles. Therefore, the availability of new landmass should not be the only criterion for the quick selection of a project site, and residual flow-sediment regime needs to consider as an additional parameter for such decision-making process.展开更多
文摘River dynamics play the most vital role in the socio-economic of the country. These rivers are highly dynamic in nature which causes extensive riverbank erosion. Active river bank erosion and bed scouring, is apprehended to change the scenario, leading to loss of limited valuable land of Bangladesh. River training is being practiced in Bangladesh since 1960s but the process is very expensive especially in the Ganges and the Jamuna Rivers. Five types of river training works were selected at different reaches. Hydro-morphological characteristics of the major rivers are being evaluated not only in engineering concepts but also in socio-economic and environmental aspects. PRA （participatory rural appraisal） tools were applied to evaluate protection safety, hydraulic and hydrological connectivity, ecological and environmental characteristics, causes of failure and social acceptability. This comparative study is being carried out for closing the gap between the modem river training works and in country experience through adaptation of research findings with a view to effectively arresting river bank erosion. Sirajganj Hardpoint, Chandpur Town Protection work and Nakalia Revetment are found to be suitable and effective. A technically suitable structure may not have good social acceptance without IWRM （integrated water resource management）.
文摘The Payra is a tidal river with meandering planform in which around 6.5 km long landmass is formed naturally during the last 40 years that is selected for an establishment by the Government of Bangladesh. However, the site experiences intermittent erosion at several locations and poses threat to the newly developed infrastructures. In the present study, a Rouse type simple model is used to estimate the equilibrium profiles of suspended sediment concentration below which the system is likely to be eroded and regarded as “Sediment Deficit System, SDS” and above which the system is likely to be sedimented and regarded as “Sediment Surplus System, SSS”. The model was then tested at the study reach using the measured flow-sediment data complemented by field observation and Landsat images-based planform analysis. The analysis revealed that the residual flow-sediment regime in the study site is representing the “sediment deficit system” that causes continuous threat for erosion throughout the tidal cycles. Therefore, the availability of new landmass should not be the only criterion for the quick selection of a project site, and residual flow-sediment regime needs to consider as an additional parameter for such decision-making process.
