The Brahmaputra River Flooding, Erosion, and Modeling for Sustainable Solutions

The Brahmaputra River, a large river system in Asia flowing 2,880 km from the Upper Himalayas to the Bay of Bengal through China, India, and Bangladesh, has been causing serious flooding and bank erosion damages in its nearly 800 km reach in the Indian state of Assam after its steep fall (~3 km) through approximately 250 km long narrow gorge crossing the China-India border. Unlike flooding, damages caused by erosion of the banks, including taking away residential properties, schools, cultural establishments, agricultural and industrial lands, and forests (state and national) serving homes for animals with endangered species, and even the flood control levees protecting the above, are permanent. Therefore, adequate erosion-control measures must be placed at active bank erosion sites to protect the above. There are many scientific challenges as the river is uniquely large and unstable. It has four constrictions playing major roles. A mathematical model of the river is needed to carefully study the river, account for effects of the constrictions and other features, and use it to design and align an adequate and stable channel of the river with sufficient capacity to convey the incoming flows of water and sediment. Next the stable and optimally aligned channel must be built and maintained using bank stabilization technologies and minimal dredging. In this paper and presentation, brief descriptions of the Brahmaputra River, its flooding and bank erosion problems, some of the challenges in solving those, and an approach as eluded above with the help of a mathematical model to overcome the challenges are presented and discussed.