SR-26 : Erosion, sedimentation and flooding in river Kosi

Abstract

River kosi which originates at an altitude of over 7000 meter in Himalayas and fin lly discharges in to river Ganga at Kursela (Bihar) is one of the major rivers of the region. it traverses a total distance of 468 km and passes through Tibet, Nepal and India. It is a river which is very notorious for shifting its course considerably. The river is also known as "Sorrow of Bihar" as it is known for creating flood havoc. The major hydrological problems of the river are erosion, sedimentation, meandering, flooding and under utilisation of its water resources potential. Number of excellent studies have been conducted on the river since 1883. These studies have been conducted by individuals, state department, Govt. of India, Universities etc. however, no attempt seems to be made to compile the information at one place.

Keeping in view the importance of river for the country in general and state of Bihar in particular the "Regional Centre" look up the challenge in task of systematically reviewing the various studies conducted on the river. During this study it was observed that there has been a lot of duplication because compilation of past studies conducted on the river is not available. The present study provides a clear picture of various features of river including geology, geomorphology, Hydrometeorology and Hydrology. The two major problems of the river i.e. erosion and sedimentation have been dealt with in details and the reasons for excessive erosion have been identified.’ The various measures which have been adopted for controlling these two hydrologic phenomenon have been described and effectiveness of such measures have been evaluated. The other major problem of the river- flooding has also been focused by providing history of floods, damages occurred, reason for floods and mitigation measures adopted.