MORPHOLOGICAL EVOLUTION OF KOSI RIVER

Abstract

The river Kosi is well known for its shifting tendency. The river shifted a distance of more than 150 km in a period of last 200 years. The shifting of river occurs due to the heavy amount of sediment that it carries from the young mountains of Himalaya. The change in morphology of the river is to be studied regularly and to be compared with its pattern in previous years, which will give an idea about the change in pattern. This is because the sudden change in path of the river causes huge loss of life and property as in the case of 2007 flood in the Kosi river. In this study the braiding pattern of Kosi river in the area upstream of Barrage from Barahkshetra to Birpur is obtained by using several indices. The Landsat 5 images of two different year i.e. of 2005 and 2016 to know the parameters such as length of sandbar, length of center channel, length of mid channel etc. to find the intensity of braiding in two different years. Several researchers provided various equations to calculate the braiding intensity, three of the equations are selected to calculate braiding intensity in two different years. The intensity thus obtained from the three equations are compared and analyzed to show the change in the braiding of the river.