ABSTRACT
In this paper BEHI-NBS method along with Geographic Information System (GIS) based technique has been proposed to estimate the river bank erosion rate. BEHI-NBS model proposed by Rosgen is mainly based on the morphological characteristic of river, erodibility potential and erosivity of bank material.
River bank erosion has caused serious problem in rivers of Nepal, engulfing villages and towns, causing bridge and roads failure, loss of property and lives. The excessive scour of fine bed materials, meander development and shifting of channel or channel migration intensify river bank erosion.
In field thirty survey locations were selected on either bank (right and left bank) of river alternately based on Google image and Global Positioning System in preliminary survey. To predict the rate of bank erosion of channel, bank erosion hazard index and near-bank stress (BEHI-NBS) method was reviewed and used and for validation the rate of shifting was found out by overlaying Google images of 2005, 2012 and 2014 and Landsat image 1984 in ArcMap 10. Actual river bank erosion rate per year was then calculated overlaying the images of different year and using different tools in GIS (Arc Map 10). All the parameters used to quantify the bank erosion hazard index showed that, the study section has high river bank erosion potential. BEHI-NBS method was found to be good predictor of river bank erosion rate for the river.
