Title: Paleo-avulsion dynamics and morphological behaviour of the Kosi River in North Bihar, India

Authors: Nikhil Roy; Suraj Prasad; Ved Prakash; Jyotsna Verma; David Haflongbar

Addresses: Department of Geography, Mariani College, Dibrugarh University, Mariani, 785634, India ' Department of Geography, Central University of Jharkhand, Ranchi, 835222, India ' Department of Geography, Veer Kunwar Singh University, Ara, Bihar, 802301, India ' Ministry of Minority Affairs, Government of India, New Delhi, 110001, India ' Department of Geography, Mariani College, Dibrugarh University, Mariani, 785634, India

Abstract: The Himalayan rivers exhibit large seasonal variations in sediment properties and dynamic flow regimes triggered by multifaceted factors like discharge, slope and bed materials. Originating in the Nepal Himalayas, the Kosi is a transboundary river known for its unique geomorphological and hydrological characteristics. Often called the "Sorrow of Bihar", the Kosi brings high sediment loads, frequent channel changes, and widespread flooding during the monsoon, resulting in widespread devastation in the northern plains of Bihar, India. Thus, the present study examines the river's avulsion dynamics through historical records, revealing that the river migrated 115 km westward between 1736 and 1949, causing devastating floods. The present study adopts the Plan Form Index (PFI) to understand the braiding behaviour of the river. It has been observed from the study that the river has shown an increasing braiding tendency, indicating the escalating channel instability in the river.

Keywords: Kosi; morphology; avulsion; floods; PFI; plan form index.

DOI: 10.1504/IJW.2024.144665

International Journal of Water, 2024 Vol.16 No.3, pp.240 - 258

Received: 04 Jul 2024
Accepted: 17 Nov 2024
Published online: 26 Feb 2025 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article