River bank protection measures in the Brahmaputra-Jamuna River: Bangladesh Experience Maminul Haque Sarker (msarker@cegisbd.com), Jakia Akter (jakia_cegis@yahoo.com), and Md. Ruknul Ferdaous Center for Environmental and Geographic Information Services (CEGIS), Dhaka, Bangladesh Presenting authors: Jakia Akter 1. Introduction The Jamuna River is the downstream reach of the Brahmaputra River in Bangladesh. It is braided in nature and its channels are very dynamic. During the last few decades, the Jamuna River has increased its braiding intensity and width. The rate and fluctuation of water flow as well as sediment transport, which are very high, result in erosion/deposition, channel shifting and bar (char) development. Bed materials and bank materials of the river have very little resistance against erosive forces generated by the flow. The planform changing process includes changes in width, braiding intensity and extent of annual bank erosion. At present the length-averaged width of the river is more than 12 km. The annual rate of riverbank erosion is very high–several thousand hectares per year, which causes millions of people to suffer every year. The cost of the riverbank protection along the Jamuna River is very high. The Bangladesh Water Development Board (BWDB) has been trying to protect the riverbank with its limited resources in order to reduce the suffering of the people and minimize national losses. Rapid channel development/abandonment and channel shifting make the protection work complicated. Since the early 1970s, bank protection works in the Jamuna River have been practised. The Sirajganj town protection works of the 1970s is probably the first major intervention for protecting the river Jamuna. Several bank protection works were constructed during the last one and half decades. Different types of bank protection works were tried with different construction materials to obtain an economic but sustained solution for the Jamuna River. This article attempts to evaluate the overall performance of different types of structures constructed with different materials along both banks of the Jamuna River in reducing the river bank erosion. Satellite images were mainly analyzed to understand the natural bank erosion processes along the right and left sides of the river. Attempt was made to separate the natural process/trend from the effects of the structures on the bank erosion process. Satellite images were also used to assess the performance of individual structures. Many of the bank protection works have been sitting idle for several years within a protecting shell of attached bar and some of those are only exposed to minor braided channels. The performance/stability of those structures could not be assessed using their age. Rather the number of years of exposure to the flow of the major braided channels has been considered as indicator of the stability of the structure. The results of this study will help to understand the natural process and guide the selection of appropriate interventions for further bank protection works.