Channel a natural passageway or perceptible depression containing continuously or periodically flowing water, or forming a connecting link between two bodies of water. Channels may be of three types: (i) a river bed; (ii) a relatively narrow stretch of sea between two landmasses and connecting two more extensive areas of sea; and (iii) the deep, navigable part of a bay, harbour, etc. In Bangladesh, the first form of channel is quite extensive.
The river channels of Bangladesh are classified on such basis as morphological features of the network, relationship to bed and bank characteristics, sedimentary or hydrological processes, morphology of the channel or its pattern, or stability of the channel. On the basis of channel planform, the rivers of Bangladesh may be divided into three patterns: (i) meandering, (ii) braided, and (iii) anabranching. The padma and the meghna are examples of meandering channel, the jamuna of the braided type, and the deltaic estuarine rivers are instances of anabranching channels. The anabranching channels are also seen in the coastal areas. Most of the channels are used extensively for navigation and fishing. Some important coastal channels are Maheshkhali, Kutubdia, Tentulia and Sandwip. [Mohd Shamsul Alam] [Alam, Mohd Shamsul Professor of Geography and Environment, Jahangirnagar University]