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Avulsion threshold and planform dynamics of the Kosi River in north Bihar (India) and Nepal: A GIS framework

DSpace at IIT Bombay

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Title Avulsion threshold and planform dynamics of the Kosi River in north Bihar (India) and Nepal: A GIS framework
 
Creator SINHA, R
SRIPRIYANKA, K
JAIN, V
MUKUL, M
 
Subject Alluvial rivers
Planform dynamics
Avulsion models
Threshold condition
Avulsion prediction
Kosi River
BAGHMATI RIVER
AUGUST 2008
SYSTEM
PLAINS
AGGRADATION
DEPOSITION
FREQUENCY
MODEL
BASIN
 
Description Models for river avulsions have identified the ratio between down-valley and cross-valley slopes of channels as the triggering factors for the sudden channel shift but have remained untested in the field. The August 2008 avulsion of the Kosi River at Kusaha, 12 km upstream of the Kosi barrage in Nepal, provided an opportunity to study a large-scale avulsion (similar to 120 km) for its causal factors and driving mechanisms. We used the SRTM-based digital elevation model and remotely sensed data coupled with field topographic mapping with a kinematic GPS and a Total Station to characterise a similar to 50-km-long stretch of the Kosi River. We have computed reach-scale avulsion threshold index (ATI) integrating SRTM-derived slopes and planform dynamics on a GIS platform. We show that several reaches along the Kosi River are avulsion-prone, including the Kusaha point that is consistent with the August 2008 avulsion. We suggest that apart from cross-valley and down-valley slopes, planform dynamics such as thalweg shift, sinuosity variation, and channel multiplicity significantly influence the avulsion threshold in alluvial reaches of the rivers such as the Kosi. (C) 2014 Elsevier B.V. All rights reserved.
 
Publisher ELSEVIER SCIENCE BV
 
Date 2014-12-28T15:17:56Z
2014-12-28T15:17:56Z
2014
 
Type Article
 
Identifier GEOMORPHOLOGY, 216157-170
0169-555X
1872-695X
http://dx.doi.org/10.1016/j.geomorph.2014.03.035
http://dspace.library.iitb.ac.in/jspui/handle/100/16852
 
Language English