by Institute of Water and Flood Management
DECCMA PI Professor Munsur Rahman led a seminar on ‘Recent sediment flux and its implications for river and delta management in the Ganges-Brahmaputra-Meghna system’ on 3rd April at the Institute of Water and Flood Management (IWFM) at the Bangladesh University of Engineering and Technology.
Sediment flux is the mechanism that creates the nature of a delta, and thus is essential for river and delta management. The physical sustainability of the river and delta environment is very sensitive to the volume of water and sediment that arrives from rivers upstream. In most of the planning documents in Bangladesh, the total sediment flux is assumed to be a constant value of around 1 billion tones per year. Recent models shows that, under climate change, there is likely to be an increase in sediment flux. However, this contradicts historical time series data, that shows a decreasing trend of sedimentation.
Studies on the total sediment load in the Ganges and the Brahmaputra show that the quantity transferred along the bed of the river is decreasing more rapidly than the sediment that is suspended within the water. A reduction in sediment within the system reduces the scope for offsetting future sea level rise, and thus has implications for subsidence and loss of land.
Recognising the importance of sediment quantity and flows in thus essential to manage the delta. The seminar concluded by emphasising the need for discussion and negotiation on sediment flux and water sharing to reduce the effect of dams upstream within Bangladesh and neighbouring countries. Along with the faculty members of IWFM guests from relevant organisations were also present, including Bangladesh Water Development Board, the Directorate of Bangladesh Haor and Wetland Division, Local Government Engineering Department, Centre for Environmental and Geographic Information Systems and the Bangladesh Export Processing Zones Authority.